Sparseness of the trabecular pattern on dental radiographs: visual assessment compared with semi-automated measurements

Objective

In diagnostic imaging; human perception is the most prominent, yet least studied, source of error. A better understanding of image perception will help to improve diagnostic performance. This study focuses on the perception of coarseness of trabecular patterns on dental radiographs. Comparison of human vision with machine vision should yield knowledge on human perception.

Method

In a study on identifying osteoporotic patients, dental radiographs were made from 505 post-menopausal women aged 45–70 years. Intra-oral radiographs of the lower and upper jaws were made. Five observers graded the trabecular pattern as dense, sparse or mixed. The five gradings were combined into a single averaged observer score per jaw. The radiographs were scanned and a region of interest (ROI) was indicated on each. The ROIs were processed with image analysis software measuring 25 image features. Pearson correlation and multiple linear regression were used to compare the averaged observer score with the image features.

Results

14 image features correlated significantly with the observer judgement for both jaws. The strongest correlation was found for the average grey value in the ROI. Other features, describing that osteoporotic patients have fewer but bigger marrow spaces than controls, correlated less with the sparseness of the trabecular pattern than a rather crude measure for structure such as the average grey value.

Conclusion

Human perception of the sparseness of trabecular patterns is based more on average grey values of the ROI than on geometric details within the ROI.Image perception is an important aspect of diagnostic imaging [1,2]. According to the UNSCEAR 2000 report (Volume 1: Annex D), the average number of diagnostic radiological examinations in countries with Level I healthcare is about 1000 per year per 1000 population. Therefore, it can be estimated that each European has about one radiological examination per year.The interpretation of radiographs is complicated by the variations in human anatomy and the spatial information that is lost while projecting the patient body on a two-dimensional plane [3]. Visual clues are overlooked or misinterpreted [4-6]. The diagnostic process of radiologists can be improved by the use of computers [7-11]. Pattern-recognition techniques have been designed to draw the attention of the radiologist to regions in mammograms that need careful scrutiny and interpretation [12]. Fully automated methods can screen chest radiographs for features of tuberculosis [13]. Although the results compete with human performance, the automated methods do not outperform the radiologists. It is expected that computers may eventually replace human observers in the analysis of data. However, complete replacement of the human observer is still a remote possibility [11]. For the foreseeable future, human interpretation will continue to be an inseparable element of medical imaging [14]. We need to understand the images and the technologies used to acquire and display them, but as patient treatment and care depend to a large extent on radiologists interpreting images, we also need to understand human perception and cognition. Many parameters are involved in the process of image acquisition, image processing and image display, and it is largely unknown how they should be optimised for human interpretation. Understanding the perceptual and cognitive processes involved in reading medical images will help to enhance the most useful properties of the images to improve diagnostic performance and reduce error rates [2,3,6,14-17].In dental radiography, many radiographs show bone with a radiographic trabecular pattern, an irregular meshwork of vague bright lines with fuzzy dark meshes (Figure 1). Visual assessment of the trabecular pattern in intra-oral radiographs is a method to identify women at risk of having osteoporosis. Dense trabeculation is a strong indicator of healthy bone, whereas sparse trabeculation is a sign of osteoporosis [18-20].Open in a separate windowFigure 1Radiograph of the right side of the lower jaw with region of interest 3.7×5.8 mm between the first and second premolar. This is used to measure mean and standard deviation of the grey value.At the oral radiology department of the Academic Centre for Dentistry Amsterdam, methods were developed for semi-automatic analysis of the trabecular pattern of radiographs. Measurements on the trabecular pattern of intra-oral radiographs were found to predict bone mineral density and osteoporosis [21,22].When both the visual assessment and the semi-automatic analysis had been applied to the same set of radiographs, there arose an opportunity to compare the two and to gain more insight into the human perception of the coarseness of the radiographic trabecular pattern.     

False-positive radio-iodinated metaiodobenzylguanidine (123I-MIBG) accumulation in a mast cell-infiltrated infantile haemangioma

Radio-iodinated metaiodobenzylguanidine (¹²³I-MIBG) is used for the detection and staging of neuroblastoma, pheochromcytoma and other neuroendocrine tumours in diagnostic nuclear medicine. A specific uptake and storage mechanism provides the basis for imaging with ¹²³I-MIBG. Nevertheless, cases of false-positive ¹²³I-MIBG scintigraphy with accumulation in non-chromaffin tumours have been described. Here, we present a case of a false-positive ¹²³I-MIBG scan in a case of a mast-cell infiltrated infantile haemangioma and discuss the possible uptake mechanism.Radio-iodinated metaiodobenzylguanidine (¹²³I-MIBG) has been used for several years for the detection and staging of neuroblastoma, pheochromcytoma and other neuroendocrine tumours. ¹²³I-MIBG is transported across the plasma membrane by the human norepinephrine transporter (NET); a smaller amount enters the cell by passive diffusion. Intracellularly, the vesicular monoamine transporters (VMATs) accumulate ¹²³I-MIBG in catecholamine storing granules [1, 2]. This specific uptake and storage mechanism provides the basis for the imaging of neuroendocrine tumours such as pheochromocytomas and neuroblastomas. Nevertheless, cases of false-positive ¹²³I-MIBG scintigraphy with accumulation in non-chromaffin tumours such as angiomyolipoma [3], adrenocortical carcinoma [4], adrenocortical adenoma [5], juvenile capillary angioma [6] or cavernous haemangioma [7] have been described. Here, we present another case of a false-positive ¹²³I-MIBG scan of a tumour within the adrenal gland area and discuss the possible mechanism. A 3-month-old girl presented with constipation. Abdominal ultrasound showed a round, strictly delineated, inhomogeneously hypoechogenic structure with a diameter of 18 × 30 mm at the upper renal pole. On the basis of these findings, adrenal haemorrhage was suspected. A follow-up ultrasound examination 6 weeks later confirmed the structure. The inhomogeneous appearance of the structure was increasing; the diameter was unchanged. An MRI examination of the abdomen was performed on a 1.5 T system (Avanto; Siemens, Erlangen, Germany). The following imaging sequences were applied: coronal T₂ weighted (_w) STIR-BLADE [8], repetition time/echo time (TR/TE) 4500/47 ms; transversal T_2w BLADE (TR/TE, 5640/118 ms); coronal T_1w BLADE (TR/TE, 1280/55 ms); transversal T_1w BLADE (TR/TE, 1400/55 ms) and transversal T_1w TSE (TR/TE, 510/9.5 ms). On T_2w images, the tumour mass proved to be only of moderate hyperintensity. The size was 34 × 22 × 28 mm, located in the area of the right adrenal gland. After application of 1 ml gadoteridol (Prohance; Bracco Diagnostics, Princeton, USA), the tumour showed an intensive contrast media enhancement (Figure 1). A ¹²³I-MIBG scan was obtained, which showed focal tracer uptake in the area of the right adrenal gland (Figure 2), corresponding to the tumour mass in the MRI examination (Figure 3) and suggestive of neuroblastoma. On the basis of the imaging data, neuroblastoma with negative urine vanillylmandelic acid and positive ¹²³I-MIBG scintigraphy was assumed and an open biopsy was performed. During surgery, a highly vascularised tissue was found in the adrenal gland. The histological examination revealed a compact vascular lesion with morphological and immunohistochemical criteria (Figure 4a,b) consistent with infantile haemangioma. Within the tumour, mast cell infiltration, which was positive upon VMAT2 staining, was seen (Figure 4c,d)Open in a separate windowFigure 1Transversal T₁ weighted BLADE MRI image (repetition time/echo time 1400/55 ms, after injection of 1 ml gadoteridol), showing a tumour mass (red arrow) in the area of the right adrenal gland. See the intensive contrast enhancement of the tumour.Open in a separate windowFigure 2¹²³I-MIBG scintigraphy (SPECT) in transversal, sagittal and coronal projections. See the intensive accumulation of the radiotracer in the area of the right adrenal gland (blue crosshairs).Open in a separate windowFigure 3Coronal and transversal fusion images obtained after automatic coregistration using the mutual information method of the ¹²³I-MIBG SPECT and the T₁ weighted BLADE MRI data (Esoft; Siemens, Erlangen, Germany). The fused images confirm the almost identical localisation of the radiotracer uptake in the SPECT and the tumour in the MRI examination (red arrows).Open in a separate windowFigure 4Staining. (a) Hemotoxylin (HE) for tumour histology. (b) GLUT1 (brown) for glucose transporters, confirming the diagnosis of infantile haemangioma. (c) VMAT2 (brown) for amine transporters. (d) Giemsa (blue) for mast cells. Magnification throughout ×20.     

Partial breast irradiation: a review of techniques and indications

The addition of whole-breast external beam radiotherapy (EBRT) to breast-conserving surgery results in a significant reduction in the risk of death due to breast cancer, but this may be offset by an increase in deaths from other causes and toxicity to surrounding organs. Because of this, and with a view to patterns of local recurrence, irradiation of the tumour bed has been explored in selected patients with early breast cancer using a variety of radiotherapeutic modalities. This review article explores the treatment options for partial breast irradiation and examines their role within the field of breast cancer treatment.Breast-conserving surgery is a proven alternative to mastectomy in patients with early-stage breast cancer, offering equivalent disease-free and overall survival [1–3]. The addition of whole-breast external beam radiotherapy (EBRT) to breast-conserving surgery results in a significant reduction in the risk of death due to breast cancer, but this is offset by an increase in deaths due to other causes [3]. However, this increase in mortality was seen with a follow-up of over 20 years and as such reflects the use of radiotherapy techniques that have since been replaced with more sophisticated methods that allow more sparing of normal tissue. Therefore, we might not observe similar late toxicities when current EBRT techniques are analysed 20 years from now. When systemic therapy such as tamoxifen is combined with breast-conserving treatment, the risk of ipsilateral breast recurrence and distant metastases is further reduced [4]. Breast-conserving surgery is often preferred by patients, as it provides improved cosmesis and decreased psychological trauma. In some areas, however, eligible patients may not receive breast-conserving therapy for a variety of physician- and patient-based reasons [5]. Whole-breast radiotherapy (WBRT) takes 3–7 weeks with treatment once daily. This can be difficult to achieve, especially in communities where the cancer centre serves a large geographical area.Conventional WBRT has changed very little over the years; it is generally delivered using two tangential beams (Figure 1), typically of 6 MV photons. Traditionally, the dose was defined using one axial contour in the centre of the field; however, more centres are now using CT planning to ensure greater homogeneity across the breast volume, while optimising avoidance of normal tissue. Late toxicities of WBRT can include radiation pneumonitis, osteonecrosis of the ribs and cardiovascular complications. These cardiovascular incidents could contribute to the increased all-cause mortality in radiotherapy patients seen in studies, although, again, these may be decreased with modern radiotherapy techniques [2, 3, 6].Open in a separate windowFigure 1(a) Axial and (b) sagittal CT images demonstrating the isodose curves generated for a parallel opposed pair of 6 MV photon beams with wedges for whole breast radiotherapy of the right breast.In disease sites elsewhere in the body, technological developments have allowed a move towards image-based target definition with sculpting of fields around anatomically defined target volumes. Therefore, the possibility of irradiating the tumour bed rather than the whole breast in patients with early breast cancer has been explored. Some investigators would choose not to treat these patients, but radiation has been shown to decrease local recurrence in this situation [4]. In trials of lumpectomy with or without WBRT, most local recurrences in the non-irradiated arm occurred in the tumour bed with a recurrence rate elsewhere of 1.5–3.5% [1, 2, 7, 8]. Pathological examination of mastectomy specimens from patients with small unifocal invasive carcinomas has shown that invasive tumour foci are generally confined to a narrow margin around the invasive tumour component [9, 10].Therefore, partial breast irradiation (PBI) is being investigated as an alternative treatment for selected patients with early-stage breast cancer. The use of PBI may improve the underutilisation of breast-conserving treatment by decreasing the time, cost and inconvenience of WBRT and improving the quality of life of patients. Case selection is the paramount factor in ensuring the suitability of a patient for PBI, combining pre-operative and surgical tumour staging to exclude patients at a higher risk of locoregional recurrence.A number of methods of PBI exist. Using photons or electrons, a single treatment can be given at the time of surgery [11–13]. EBRT can be used to deliver a partial breast treatment with electrons, conventional beam approaches or intensity-modulated radiotherapy (IMRT) techniques. Brachytherapy can be delivered using low dose rate (LDR), pulsed dose rate (PDR) and high dose rate (HDR) isotopes delivered by way of a single catheter or multiple catheter implants. Many of the data surrounding these different modalities are from Phase I or II trials, but increasing numbers of patients are being enrolled into Phase III randomised trials.     

Air encircling the intussusceptum on air enema for intussusception reduction: an indication for surgery?

Objectives

The prompt identification of children in whom enema reduction of intussusception might fail and surgery is necessary is crucial in order to avoid futile repeat attempts and untoward complications. The purpose of this retrospective review was to determine whether air encircling the intussusceptum in the small bowel during air enema for intussusception reduction could serve as an indication for operation rather than repeat attempts at radiological reduction.

Methods

Imaging studies of 83 children aged 4 to 40 months with idiopathic intussusception who had air enema for intussusception reduction were reviewed for the presence of air encircling the intussusceptum in the distal small bowel. Findings were correlated with clinical course and surgical findings.

Results

In 12 of 83 patients, air was seen encircling the intussusceptum in the small bowel, and in 11 of these (88%) air enema failed to reduce the intussusception. In 8 of the 11, delayed repeated attempts using air enema failed to reduce intussusception. Clinical signs and their duration did not differ between those children without and those with air encircling the intussusceptum.

Conclusion

In the presence of air encircling the intussusceptum in the distal small bowel on air enema, delayed repeated attempts for intussusception reduction are unlikely to succeed, and surgery is indicated.Since the advent of enemas for the treatment of idiopathic ileocolic intussusceptions, the rate of surgical reduction has fallen drastically and radiographically controlled reduction has become the mainstay of treatment [1,2]. Mass use of ultrasound as a diagnostic modality has led to earlier detection, with a higher success rate for enema reduction of intussusceptions [2]. While most cases of ileocolic intussusception are successfully reduced without surgery, there remains a subgroup of paediatric patients who require operative intervention [3,4]. The presence of shock, peritonitis or perforation with free air obviates the enema trial [5,6]. Most patients with ileoileal intussusception or intussusception with a pathological lead point on sonography can also be reduced by air enema in an acute situation [7]; surgical treatment may be indicated at a later date.When complete reduction at the level of the caecum fails, repeat attempts using enema may be appropriate if the child''s clinical status permits [2,8-12]. If repeat attempts fail, reduction is performed surgically. There is an ongoing quest for clinical and imaging criteria that can differentiate between patients who can benefit from repeat air enema after initial failure and those who require surgery [11-13]. This differentiation is important, since a delay in reduction may lead to a severe compromise of bowel viability [14].There are currently very few clinical or imaging findings considered specific to predict irreducibility for the minority of patients in whom radiological reduction fails [2]. The “dissection sign” on barium enema has been reported as an indication of ileocolic or colocolic intussusception that requires surgery [15]; however, barium enema is currently not used as frequently as air enema for intussusception reduction [4]. In one report, an “appendix sign” on air enema has been reported as an indication for surgical intervention [16].Over a 3 month period, 4 children aged 5–18 months presented to our emergency department with intermittent abdominal pain and vomiting of 1–2 days’ duration. The children were otherwise healthy, and on presentation had no clinical signs indicating bowel necrosis or peritonitis. Abdominal sonography showed ileocolic intussusception with vascular flow in the bowel wall in colour Doppler in all patients. Air enema reduction was attempted and the intussusception was reduced to the level of the caecum in all four patients, but failed to reduce into the small bowel. Instead, upon reaching the caecum, a mobile intussusception encircled by air, protruding into the caecum on a stalk, was noted (Figures 1 and ​and2).2). Reflux of air around the intussusceptum into the terminal ileum was observed in all cases. Despite the prolonged presence of air around the intussusceptum in the caecum and the terminal ileum, the intussusception could not be reduced. Repeat sonography was performed in two of these patients and confirmed the persistence of an ileocolic intussusception (Figures 2 and ​and3).3). Delayed repeated attempts to reduce the intussusception were unsuccessful, and each patient was ultimately transferred to the operating room for laparotomy.Open in a separate windowFigure 1Intussusception in a 12-month-old girl who presented with fever and restlessness for 48 h. Fluoroscopy image in the prone position demonstrates the intussusception (I), surrounded by air (arrows), protruding through the ileocaecal valve on a narrow stalk (arrowheads).Open in a separate windowFigure 2Intussusception in a 14-month-old boy who presented with abdominal pain and bloody diarrhoea for 72 h. Fluoroscopy image in the prone position (a) demonstrates the intussusception (I), surrounded by air (arrows), protruding through the ileocaecal valve on a short stalk (arrowheads). A small amount of air is seen in the distal small bowel (white arrows). On sonography (b), the intussusceptum head (I) is surrounded by tiny echogenic dots (arrows), representing air between the intussusceptum and the intussuscipiens.Open in a separate windowFigure 3Intussusception in a 4-month-old boy who presented with diarrhoea for 24 h. Fluoroscopy image in the prone position (a) demonstrates the intussusception (I), surrounded by air (arrows), protruding through the ileocaecal valve. A small amount of air can be seen in the distal small bowel (white arrow). Repeat sonography (b) confirmed the persistence of the intussusception and demonstrated tiny echogenic dots representing air (arrows) between the intussusceptum head (I) and the intussuscipiens mucosa. ff, free fluid. Fluoroscopy during a delayed reduction attempt (c) demonstrates the persisting intussusception (I) and free air, delineating the transverse colon (arrowheads), as confirmed in an oblique view (d), anterior and posterior to the liver (L) and under the diaphragm (arrows).Operative findings in all four patients were similar: ileoileal intussusception starting proximal to the ileocaecal valve and protruding into the colon, leaving the caecum intact (ileo-ileocolic intussusception). No pathological lead point was found. Manual reduction was uneventful; there was no need for bowel resection in any of the patients.In view of these findings, we reviewed imaging studies and patients’ records of all children treated for intussusception in our hospital over a 3.5 year period. The purpose of our study was to determine whether air encircling the intussusceptum in the distal small bowel during air enema for intussusception reduction could serve as a sign predicting necessity for operation rather than repeat attempts at radiological reduction.     

Enhancement of the radiation response of EMT-6 tumours by a copper octabromotetracarboranylphenylporphyrin

Objective

The carborane-containing porphyrin, copper (II) 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(3-[1,2-dicarba-closo-dodecaboranyl]methoxyphenyl)-porphyrin (CuTCPBr), was investigated as a potential radiation enhancing agent for X-ray radiotherapy (XRT) in a subcutaneously implanted EMT-6 murine carcinoma.

Method

The biodistribution and toxicological profile of this porphyrin has been shown to be favourable for another bimodal radiotherapy technique, boron neutron-capture therapy. For the XRT studies, CuTCPBr was formulated in either 9% Cremophor® (BASF Corporation, Ludwigschafen, Germany) EL and 18% propylene glycol (9% CRM) or a revised formulation comprising 1% Cremophor ELP, 2% Tween 80® (JT Baker, Mansfield, MA), 5% ethanol and 2.2% PEG 400 (CTEP formulation), which would be more clinically acceptable than the original 9% CRM formulation. Using the 9% CRM formulation of CuTCPBr, doses of 100, 210 or 400 mg kg⁻¹ of body weight were used in combination with single doses of 25–35 Gy 100 kVp X-rays.

Results

While doses of 100 mg kg⁻¹ and 210 mg kg⁻¹ did not result in any significant enhancement of tumour response, the 400 mg kg⁻¹ dose did. A dose modification factor of 1.20±0.10 was obtained based on the comparison of doses that produced a 50% local tumour control probability. With the CTEP formulation of CuTCPBr, doses of 83 and 170 mg kg⁻¹ produced significant radiation enhancement, with dose modification factors based on the TCP₅₀ of 1.29±0.15 and 1.84±0.24, respectively.

Conclusion

CuTCPBr significantly enhanced the efficacy of XRT in the treatment of EMT-6 carcinomas in mice. The CTEP formulation showed a marked improvement, with over 9% CRM being associated with higher dose modification factors. Moreover, the radiation response in the skin was not enhanced.Porphyrins are used in the treatment of cancer, as photosensitisers in clinical photodynamic therapy (PDT) and as boron carriers in preclinical studies of boron neutron-capture therapy (BNCT) [1-4]. Both approaches use the porphyrin as part of bimodal therapy, in which the cell-killing chemical species are only formed when both the porphyrin and radiation are present in the form of light or thermal neutrons, respectively. Selectivity is attained because the porphryins predominantly localise in tumour tissue within the irradiated volume. Such a strategy can also be used with conventional X-ray therapy (XRT), by using a porphyrin with a different set of physicochemical requirements, while maintaining similar biological requirements, such as tumour selectivity and low toxicity. For example, haematoporphyrin, used for PDT, has been reported to have some activity in enhancing the effect of X-rays [5,6]. The porphyrin, verteporfin, has also been used in combination therapy involving both PDT and XRT [7]. Results from animal studies, based on the endpoint of tumour growth delay, suggested a synergistic rather than just an additive effect [7]. The manganese tetrapyridylporphyrins (known as mimetics of superoxide dismutase) have also been shown to increase tumour response to XRT [8,9]. They are believed to act by inhibiting tumour angiogenesis, which is activated by oxidative stress, a well-recognised occurrence after exposure to ionising radiation.The only porphyrin-like compound currently being clinically investigated as a radiation enhancement agent is an expanded porphyrin with gadolinium at the centre, known as gadolinium texaphyrin (Gd-Tex) or motexafin [10-12]. It has a high electron affinity with a relatively positive reduction potential, which is believed to be at least partially responsible for its effectiveness. It has been shown that electron-affinic aromatic compounds can act as oxygen mimetic sensitisers in hypoxic radioresistant cells, which are frequently found in malignant tissue [13,14]. Reactive oxygen species (ROS), comprising free radicals, peroxides and superoxides, are believed to be the active species created primarily from the radiolysis of water during exposure to ionising radiation. Although many potential XRT sensitisers that maximise the concentration of ROS have been studied in pre-clinical and clinical trials, none are used routinely in the clinic. Temozolomide and cetuximab have been used with radiation, but their function is primarily chemotherapeutic [15,16]. However, there is evidence that temozolomide will inhibit the repair of radiation-induced damage to DNA in the presence of the methylated version of the MGMT (O⁶-methylguanine–DNA methyltransferase) DNA-repair gene, which explains the greater efficacy of this drug/radiation combination in the treatment of glioblastoma multiforme [17].Copper (II) 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(3-[1,2dicarba-closo-dodecarboranyl]methoxyphenyl)-porphyrin (CuTCPBr) (Figure 1) was initially synthesised as a boron carrier for use in BNCT. It has been shown to possess the biological properties needed for this treatment modality, i.e. high tumour boron localisation and low toxicity [18]. Moreover, besides having the necessary high boron content, it should also have a significantly higher electron affinity owing to the electron-withdrawing bromo groups on the macrocycle. To determine its electron affinity, redox potentials were measured and compared with similar copper brominated porphyrins.Open in a separate windowFigure 1Porphyrin structures of CuTCPBr, CuTPP and CuTPPBr₈. Closed circles represent C or CH and open circles represent BH in CuTCPBr.The purpose of this article is to study the biodistribution of CuTCPBr and to evaluate its therapeutic efficacy in combination with single doses of X-rays using the murine EMT-6 tumour model. Data for this porphyrin were acquired using direct-current plasma atomic emission spectroscopy (DCP-AES) to assay boron concentrations, since the boron and porphyrin are covalently linked. CuTCPBr is not water soluble and, therefore, requires formulation for in vivo studies. The first approach was to use the standard preclinical formulation used for lipophilic porphyrins, which has been adopted in the Medical Department, Brookhaven National Laboratory, and comprises 9% Cremophor® (BASF Corp., Ludwigschafen, Germany) EL and 18% propylene glycol (9% CRM formulation) with a CuTCPBr concentration of approximately 3.5 mg ml⁻¹ [4,19]. However, for clinical use, more concentrated solutions with significantly lower amounts of Cremophor are required. To this end, a formulation comprising 2% Cremophor ELP, 1% Tween 80® (JT Baker, Mansfield, MA), 5% ethanol and 2.2% PEG 400 (CTEP formulation), developed by Applied Analysis Ltd (Beverley, East Yorkshire, UK) was also used.     

Hysterosalpingogram: an essential examination following Essure hysteroscopic sterilisation

Objectives

The aim of this study was to describe our experience of imaging following hysteroscopic sterilisation with the Essure (Conceptus Inc., Mountain View, San Carlos, CA) microinsert, and to underline the importance of a carefully performed follow-up hysterosalpingogram (HSG) in the management of these patients.

Methods

18 women underwent the procedure and all returned for follow-up HSG. A standard HSG technique was used and views were acquired to establish microinsert position and tubal occlusion.

Results

In 16 of the 18 women, adequate microinsert positioning and bilateral tubal occlusion was present. In one woman, a unilateral microinsert occluded the fallopian tube, whereas the other fallopian tube was ligated with a clip. The final patient underwent two studies; both showed well-positioned microinserts but unilateral free spill from the right fallopian tube. There are no reported pregnancies thus far.

Conclusion

Essure sterilisation coils have a unique appearance when radiographed and are an effective means of permanently occluding the fallopian tubes. HSG is a rapid and safe method of confirming satisfactory placement and tubal occlusion. Non-HSG imaging techniques are suboptimal at detecting patent fallopian tubes and expose patients to the risk of an unwanted and potentially complicated pregnancy.Although there have been numerous advances in the methods available for contraception, female tubal sterilisation represents one of the most popular. It is the method of choice for birth control for approximately 180 million couples worldwide [1]. 700 000 procedures are performed annually in the USA [2] and 49 000 procedures annually in the UK [3]. Traditionally, tubal “interruption” has been performed laparoscopically, at laparotomy or minilaparotomy, vaginally via the posterior fornix or transcervically via the hysteroscope. The procedure may be performed under local anaesthetic with sedation or under general anaesthetic and employs any combination of cautery, electrocoagulation, ligation, clipping, division of the fallopian tubes, intratubal devices or chemicals. All of these methods have an associated morbidity and failure rate, with the subsequent risk of an unwanted pregnancy. The United States Collaborative Review of Sterilization (CREST) reported a cumulative probability of pregnancy 5 years after tubal surgery of 13.1 per 1000 procedures and 18.5 per 1000 procedures after 10 years, with 33% of these pregnancies being ectopic [4]. Some methods offer the chance of reversal at a later date if desired.To date, the main methods of transcervical sterilisation have involved introduction of chemicals such as quinacrine, electrodiathermy or mechanical obstruction, all with varying rates of success [2]. The most recent and promising advance in sterilisation techniques involves the concept of transcervical tubal cannulation and placement of an intrafallopian implant. Tubal sterilisation using the Essure microinsert (Conceptus Inc., Mountain View, San Carlos, CA) offers a permanent, irreversible alternative which is performed hysteroscopically under mild sedation in an outpatient setting [5-8]. The device was approved by the United States Food and Drugs Administration (US FDA) in November 2002 and by the UK National Institute for Health and Clinical Excellence (NICE) in February 2004. To date, over 200 000 women have undergone sterilisation with Essure microinserts worldwide.The Essure microinsert consists of a stainless steel inner coil, a radially expanding nickel–titanium alloy (nitinol) outer coil and polyethylene terephthalate (PET) fibres wound in and around the inner coil (Figure 1) [8]. The ends of the inner and outer coils are delineated by radio-opaque markers. There is no hormonal element to the system. The insert is 4 cm long and the outer coil expands to 1.5–2 mm to anchor it in the fallopian tube. The manufacturers recommend that between three and eight coils of the outer coil are left trailing into the endometrial cavity. The microinsert is delivered via the hysteroscope using a single-handed ergonomic handle containing a delivery wire, and delivery and release catheters. After placement, the presence of the PET fibres induces an inflammatory reaction that leads to intraluminal fibrosis over a 3 month period; this achieves the dual effect of fallopian tube anchorage of the microinsert as well as tubal occlusion [8]. Although far more commonly performed hysteroscopically, placement under fluoroscopic guidance has been described [9]. The microinserts have been shown to be MRI-compatible up to a field strength of 1.5 T [10].Open in a separate windowFigure 1Essure hysteroscopic sterilisation device. From Essure [8], courtesy of Conceptus, Inc (Mountain View, San Carlos, CA).The device is usually inserted in an outpatient day-care setting, with most patients requiring mild sedation and/or local anaesthesia, ideally during the early proliferative phase of the menstrual cycle. When performed by an experienced operator, the procedure usually takes less than 10 min to complete [11,12]. Patients are advised to use non-steroidal anti-inflammatory drugs (NSAIDs) for analgesia, are discharged within hours of the procedure and most return to normal daily activities within 24 h [13]. They are advised to use additional contraception for 3 months prior to imaging to demonstrate satisfactory tubal occlusion.     

Long-term results of radiofrequency ablation for unresectable colorectal liver metastases: a potentially curative intervention

Objective

The long-term results and prognostic factors of radiofrequency ablation (RFA) for unresectable colorectal liver metastases (CRLM) in a single centre with >10 years of experience were retrospectively analysed.

Methods

A total of 100 patients with unresectable colorectal liver metastases (CRLM) (size 0.2–8.3 cm; mean 2.4 cm) underwent a total of 126 RFA sessions (237 lesions). The mean follow-up time was 29 months (range 6–93 months). Lesion characteristics (size, number and location), procedure characteristics (percutaneous or intra-operative approach) and major and minor complications were carefully noted. Local control, mean survival time and recurrence-free and overall survival were statistically analysed.

Results

No direct procedure-related deaths were observed. Major complications were present in eight patients. Local RFA site recurrence was 12.7% (n = 30/237); for tumour diameters of <3 cm, 3–5 cm and >5 cm, recurrence was 5.6% (n = 8/143), 19.5% (n = 15/77) and 41.2% (n = 7/17), respectively. Centrally located lesions recurred more often than peripheral ones, at 21.4% (n = 21/98) vs 6.5% (n = 9/139), respectively, p = 0.009. Including additional treatments for recurring lesions when feasible, lesion-based local control reached 93%. The mean survival time from RFA was 56 (95% confidence interval (CI) 45–67) months. Overall 1-, 3-, 5- and 8-year survival from RFA was 93%, 77%, 36% and 24%, respectively.

Conclusions

RFA for unresectable CRLM is a safe, effective and potentially curative treatment option; the long-term results are comparable with those of previous investigations employing surgical resection. Factors determining success are lesion size, the number of lesions and location.Colorectal carcinoma is one of the most common malignancies in Western countries. In 20–25% of patients with colorectal carcinoma (synchronous) liver metastases are present at the time of diagnosis of the primary tumour [1-3]. Another 20–30% of patients develop (metachronous) liver metastases, which usually arise within 3 years of initial treatment of the primary tumour [1,3]. In Europe and the USA, colorectal liver metastases (CRLM) are the most frequent cause of malignant hepatic tumours [4]. The prognosis of patients with untreated CRLM (receiving only symptomatic therapy) is poor, with a median survival rate of 4.5–12 months, depending on the extent of metastatic disease at the time of diagnosis [5]. Chemotherapeutics, using oxaliplatin and fluorouracil (5FU), can prolong survival in a palliative setting with a median survival of approximately 18 months [6-8]. More recent results show a median survival of 21.7 months for patients treated with capecitabine, irinotecan and oxaliplatin [9]. Surgical resection is still considered the only method for definite treatment of malignant liver tumours by many [10-17]. Resection of liver metastases with curative intent results in a 5 year overall survival rate of 24–58% and a 10 year survival rate of 28% [11-19]. It is not uncommon, particularly in patients with primary colorectal carcinoma, for the liver to be the only site of metastatic disease [19]. Unfortunately, approximately 70–80% of patients with metastases confined to the liver are not suitable candidates for resection, owing to tumour anatomy (number, size and/or locations), extended extrahepatic disease and/or impaired general health status [20-22]. Therefore, several other local treatment methods such as tumour ablation, originally considered palliative procedures, have been investigated. Radiofrequency ablation (RFA) has shown promising results in the recent literature. It is a procedure with a relatively low complication rate (<10%, mostly minor complications that are often unnecessary to treat) and a very small risk of death (<1%), notably when compared with resection [20,23]. The aim of this study was to retrospectively describe the long-term results and predictive factors of RFA for unresectable CRLM.     

Prognostic factors associated with a subchondral insufficiency fracture of the femoral head

Objective

The aim of this study was to identify the risk factors associated with the prognosis of a subchondral insufficiency fracture of the femoral head (SIF).

Methods

Between June 2002 and July 2009, 25 patients diagnosed with SIF were included in this study. Sequential radiographs were evaluated for the progression of collapse. Clinical profiles, including age, body mass index, follow-up period and Singh’s index, were documented. The morphological characteristics of the low-intensity band on T₁ weighted MRI were also examined with regards to four factors: band length, band thickness, the length of the weight-bearing portion and the band length ratio (defined as the proportion of the band length to the weight-bearing portion of the femoral head in the slice through the femoral head centre).

Results

Radiographically, a progression of collapse was observed in 15 of 25 (60.0%) patients. The band length in patients with progression of collapse [22.5 mm; 95% confidence interval (CI) 17.7, 27.3] was significantly larger than in patients without a progression of collapse (13.4 mm; 95% CI 7.6, 19.3; p<0.05). The band length ratio in patients with progression of collapse (59.8%; 95% CI 50.8, 68.9) was also significantly higher than in patients without a progression of collapse (40.9%; 95% CI 29.8, 52.0; p<0.05). No significant differences were present in the other values.

Conclusion

These results indicate that the band length and the band length ratio might be predictive for the progression of collapse in SIF.Subchondral insufficiency fractures of the femoral head (SIF) often occur in osteoporotic elderly patients [1-9]. Patients usually suffer from acute hip pain without any obvious antecedent trauma. Radiologically, a subchondral fracture is seen primarily in the superolateral portion of the femoral head [4,5,10]. T₁ weighted MRI reveal a very low-intensity band in the subchondral area of the femoral head, which tends to be irregular, disconnected and convex to the articular surface [2,4,5,7,9,11]. This low-intensity band in SIF was histologically proven to correspond with the fracture line and associated repair tissue [5,9]. Some cases of SIF resolve after conservative treatment [5,11-14]; other cases progress until collapse, thereby requiring surgical treatment [4-10,15]. The prognosis of SIF patients remains unclear.The current study investigated the risk factors that influence the prognosis of SIF based on the progression to collapse.     

MRI features of serous oligocystic adenoma of the pancreas: differentiation from mucinous cystic neoplasm of the pancreas

Objectives

The purpose of this study was to describe the MRI features of the benign pancreatic neoplasm serous oligocystic adenoma (SOA) that differ from those of mucinous cystic neoplasm (MCN), a neoplasm with the potential for malignant degeneration.

Methods

Seven patients with SOA (seven women; mean age 36.6 years) and eight patients with MCN (eight women: mean age 39.9 years) were included. Several imaging features were reviewed: mass size, location, shape, wall thickness, cyst configuration (Type I, unilocular; Type II, multiple clustered cyst; Type III, cyst with internal septation) and signal intensity of the lesion with heterogeneity.

Results

SOA lesions were smaller (3.4 cm) than those of MCN (9.3 cm) (p=0.023). The commonest lesion shape was lobulated (85.7%) for SOA, but oval (50.0%) or lobulated (37.5%) for MCN (p=0.015). The most common cyst configuration was Type II (85.7%) for SOA and Type III (75.0%) for MCN (p=0.008). Heterogeneity of each locule in T₁ weighted images was visible in all cases of MCN, but in no case for SOA (p=0.004).

Conclusion

SOA could be differentiated from MCN by identifying the imaging features of lobulated contour with multiple clustered cyst configurations and homogeneity of each locule in T₁ weighted MR images.Serous oligocystic adenoma (SOA) is a recently described rare, benign pancreatic neoplasm and a morphological variant of serous microcystic adenoma, because it contains six or fewer cysts and the cysts are large (>2 cm) [1,2]. Pathologically, SOA is a benign pancreatic neoplasm composed of a few relatively large cysts uniformly lined with glycogen-rich cuboidal epithelial cells [3]. According to the World Health Organization classification, SOA is a subgroup of pancreatic serous cystic tumours and the term SOA is a synonym for macrocystic serous cystadenoma [3,4].The CT and MRI features of SOA of the pancreas are documented [2]. On CT and MRI, SOA typically appears as a small unilocular or bilocular cyst (<5 cm) with a thin wall (<2 mm) that lacks mural nodules or calcifications [2]. Because the cystic spaces are >2 cm, SOA images can be mistaken for mucinous cystic neoplasm (MCN), pseudocyst or intraductal papillary mucinous tumour [2,5-7]. It is very difficult to differentiate SOA from MCN by clinical and radiological features [2,6,8,9]. SOA does not require resection unless it causes symptoms, but MCN should be resected because of a potential for malignant degeneration [5,7,8]. Endoscopic ultrasound and cyst fluid aspiration have a role in distinguishing mucinous and serous lesions, but it is an invasive procedure with a risk of complications such as pancreatitis [10]. Therefore, it is clinically valuable to determine characteristic imaging findings that can distinguish SOA from MCN.Recently, Kim et al [6] and Cohen-Scali et al [5] described characteristic CT findings that can be used to differentiate SOA from MCN. MRI can demonstrate septa within a lesion with greater sensitivity than CT; therefore, MRI provides a better evaluation of tissue characteristics than CT [1,11]. However, few studies have described the MRI features of SOA [1,2]. The purpose of this study was to describe the differences in the MRI features of SOA and MCN in the pancreas.     

Assessment of early treatment response after CT-guided radiofrequency ablation of unresectable lung tumours by diffusion-weighted MRI: a pilot study

The aim of this study was to evaluate prospectively the early treatment response after CT-guided radiofrequency ablation (RFA) of unresectable lung tumours by MRI including diffusion-weighted imaging (DWI). The study protocol was approved by the ethics committee of our hospital and signed consent was obtained from each patient. We studied 17 patients with 20 lung lesions (13 men and 4 women; mean age, 69±9.8 years; mean tumour size, 20.8±9.0 mm) who underwent RFA using a LeVeen electrode between November 2006 and January 2008. MRI was performed on a 1.5T unit before and 3 days after ablation. We compared changes in the apparent diffusion coefficient (ADC) on DWI and response evaluation based on subsequent follow-up CT. 14 of the 20 treatment sessions showed no local progression on follow-up CT, whereas 6 treatment sessions showed local progression (range, 3–17 months; mean, 6 months). For the no-progression group, the ADC pre- and post-RFA were 1.15±0.31 × 10⁻³ mm² s⁻¹ and 1.49±0.24 × 10⁻³ mm² s⁻¹, respectively, while the respective ADC values for those that showed local progression were 1.05±0.27 × 10⁻³ mm² s⁻¹ and 1.24±0.20 × 10⁻³ mm² s⁻¹. The ADC of the ablated lesion was significantly higher than before the procedure (p<0.05). There was a significant difference in the ADC post-RFA between no-progression and local progression groups (p<0.05). Our prospective pilot study showed that the ADC without local progression was significantly higher than with local progression after RFA, suggesting that the ADC can predict the response to RFA for lung tumours.After the first report in 2000 [1], lung radiofrequency ablation (RFA) is now considered effective in the treatment of lung cancer, which is traditionally considered unresectable owing to compromised pulmonary function or advanced age. In general, complications associated with lung RFA are minimal, and favourable local control has been reported in a number of studies of tumours with a diameter of 30 mm or less [1–5]. However, only a limited number of studies have been published regarding the treatment outcome after lung RFA [6–10]. In this process, a layer of normal lung tissue surrounding the tumour is also ablated as a safety margin. Inevitably, the ablated lesion depicted on a CT scan immediately after the procedure is larger than the original tumour mass. However, this region of increased density shrinks with time, but follow-up CT may still show the ablated lesion being as big as, or larger than, the tumour size before the procedure [6, 7]. Thus, radiologists sometimes encounter difficulty in distinguishing scarred tissue from a tumour residue/local progression when the size of the lesion remains the same. Accurate assessment of RFA outcome would have important consequences, as recurrent tumours can be treated again if detected at an early stage. Different modalities of early-stage follow-up examination, such as contrast-enhanced CT [8] and fluorodeoxyglucose positron emission tomography (FDG–PET), have been of great interest and their usefulness has been reported by several groups [9, 10]. Another approach — MR diffusion-weighted imaging (DWI) — which is based on the measurement of motion of water molecules, has also been reported as a non-invasive evaluation modality [11–19]. In this method, the apparent diffusion coefficient (ADC) represents the water content and distribution, the cellular density and the cell membrane integrity, suggesting the potential usefulness of an ADC map for estimating tumour viability. Indeed, DWI has been successfully used to assess the efficacy of radiotherapy [11, 12], chemotherapy [13–15] and transcatheter arterial embolisation [16, 17]. To our knowledge, only two studies have reported the use of DWI to evaluate the therapeutic outcome of RFA [18, 19]. A previous study reported that the ADC value of an ablated rabbit tumour model (VX2 tumour) was significantly higher than that of untreated tumours, and that FDG uptake on micro-PET for small animals with ablated tumours was significantly lower than for untreated tumours. These results indicate that DWI at 2 days and FDG–PET at 3 days after RFA are both potentially feasible modalities for monitoring the early effects of the procedure [19]. In this study, we calculated the ADC in tumour lesions before and after clinical lung RFA and examined the usefulness of DWI in the early detection of tumour response to RFA.     

Radiofrequency ablation combined with transcatheter arterial embolisation in rabbit liver: investigation of the ablation zone according to the time interval between the two therapies

Objectives

This study was designed to evaluate the extent of the radiofrequency ablation zone in relation to the time interval between transcatheter arterial embolisation (TAE) and radiofrequency ablation (RFA) and, ultimately, to determine the optimal strategy of combining these two therapies for hepatocellular carcinoma.

Methods

15 rabbits were evenly divided into three groups: Group A was treated with RFA alone; Group B was treated with TAE immediately followed by RFA; and Group C was treated with TAE followed by RFA 5 days later. All animals underwent perfusion CT (PCT) scans immediately after RFA. Serum liver transaminases were measured to evaluate acute liver damage. Animals were euthanised for pathological analysis of ablated tissues 10 days after RFA. Non-parametric analyses were conducted to compare PCT indices, the RFA zone and liver transaminase levels among the three experimental groups.

Results

Group B showed a significantly larger ablation zone than the other two groups. Arterial liver perfusion and hepatic perfusion index represented well the perfusion decrease after TAE on PCT. Although Group B showed the most elevated liver transaminase levels at 1 day post RFA, the enzymes decreased to levels that were not different from the other groups at 10 days post-RFA.

Conclusions

When combined TAE and RFA therapy is considered, TAE should be followed by RFA as quickly as possible, as it can be performed safely without serious hepatic deterioration, despite the short interval between the two procedures.Surgical resection is still considered standard curative therapy for hepatocellular carcinomas (HCCs), but only a small proportion of patients can undergo curative resection at initial presentation owing to the advanced stage of HCCs or liver dysfunction caused by an underlying liver disease [1,2]. Therefore, local ablation therapy, such as radiofrequency ablation (RFA), has been widely utilised as an alternative treatment. RFA shows promising results for managing HCCs less than 3 cm in diameter [3,4]. However, managing medium-sized and large HCCs with RFA seems to be less robust owing to the limited ablation zone. One of the main reasons is that intratumoral energy by RFA is insufficient to produce complete coagulation necrosis of liver tumours probably because of the heat dispersion by blood flow. To overcome these problems, transcatheter arterial embolisation (TAE) can reduce the heat sink effect for subsequent RFA when TAE is followed by RFA, which can lead to a larger ablation zone to treat larger HCCs [5-7]. Therefore, the combined therapy is beneficial compared with TAE or RFA alone due to a synergistic effect of those two therapies, particularly when treating larger HCCs (i.e. >3 cm diameter) that do not respond adequately to either procedure alone [6,8-13].No consensus exists on the time interval between combined TAE and RFA. Kang et al [13] reported on a single-session combined therapy in which RFA was performed immediately following chemoemobolisation. Takaki et al [12] reported on a dual-session combined therapy in which RFA was performed 1–2 weeks after TAE. The extent of the ablation zone and the safety of combined therapy in relation to the time interval between the two treatments have not been investigated. During the single-session combined therapy, the ablation zone is assumed to be larger than the dual-session combined therapy owing to the maximised perfusion reduction by TAE just prior to RFA. However, acute liver damage may be more severe with the single-session combined therapy than with the dual-session combined therapy.The aim of this study was to evaluate the differences in liver perfusion, the extent of the ablation zone and the degree of acute liver damage according to the time interval between TAE and RFA, and to determine the optimal strategy for combining these two therapies for treating HCCs.     

Impact of biplane versus single-plane imaging on radiation dose,contrast load and procedural time in coronary angioplasty

Coronary angioplasties can be performed with either single-plane or biplane imaging techniques. The aim of this study was to determine whether biplane imaging, in comparison to single-plane imaging, reduces radiation dose and contrast load and shortens procedural time during (i) primary and elective coronary angioplasty procedures, (ii) angioplasty to the main vascular territories and (iii) procedures performed by operators with various levels of experience. This prospective observational study included a total of 504 primary and elective single-vessel coronary angioplasty procedures utilising either biplane or single-plane imaging. Radiographic and clinical parameters were collected from clinical reports and examination protocols. Radiation dose was measured by a dose–area–product (DAP) meter intrinsic to the angiography system. Our results showed that biplane imaging delivered a significantly greater radiation dose (181.4±121.0 Gycm²) than single-plane imaging (133.6±92.8 Gycm², p<0.0001). The difference was independent of case type (primary or elective) (p = 0.862), vascular territory (p = 0.519) and operator experience (p = 0.903). No significant difference was found in contrast load between biplane (166.8±62.9 ml) and single-plane imaging (176.8±66.0 ml) (p = 0.302). This non-significant difference was independent of case type (p = 0.551), vascular territory (p = 0.308) and operator experience (p = 0.304). Procedures performed with biplane imaging were significantly longer (55.3±27.8 min) than those with single-plane (48.9±24.2 min, p = 0.010) and, similarly, were not dependent on case type (p = 0.226), vascular territory (p = 0.642) or operator experience (p = 0.094). Biplane imaging resulted in a greater radiation dose and a longer procedural time and delivered a non-significant reduction in contrast load than single-plane imaging. These findings did not support the commonly perceived advantages of using biplane imaging in single-vessel coronary interventional procedures.The use of biplane imaging during diagnostic coronary angiography and coronary interventions has been reported to reduce the total contrast load to the patient compared with single-plane imaging [1–8]. Additionally, acquiring two simultaneous images from two orthogonal planes has been reported to be more efficient than single-plane imaging [2, 8–11]. However, there are conflicting reports as to whether the radiation dose to the patient differs between biplane and single-plane imaging during coronary studies [3, 10, 11].Biplane imaging allows two cineangiography runs to be recorded simultaneously with a single injection of contrast. With single-plane imaging, however, the same information can be acquired only by carrying out the two cineangiography runs serially with two separate injections of contrast [1, 2, 8, 10]. Biplane imaging enables the operator to visualise the target lesion in orthogonal planes simultaneously and was presumed to be more efficient than single-plane imaging, particularly in difficult procedures [1, 4, 9, 12]. Accordingly, examinations would become faster, use of fluoroscopy would be reduced, fewer cineangiography runs would be required and the average radiation dose to the patient would be comparatively lower than in the case of procedures performed with single-plane imaging. The contrast load with biplane imaging was also expected to be significantly reduced [3, 4, 11].These perceived advantages of biplane imaging have led to recommendations for its use in paediatric and adult cardiac catheter laboratories [1, 4, 5, 10, 12, 13]. A previous study comparing biplane and single-plane imaging in 1156 diagnostic coronary angiography procedures found a small, but notable, reduction in contrast load accompanied by significantly longer table times and screening times with biplane imaging, although radiation dose was not examined [14].Contrast-induced nephropathy (CIN) is a complication associated with prolonged hospitalisation and development of end-stage renal failure [15]. Patients with pre-existing renal disease, diabetes, congestive heart failure or older age are at the greatest risk in developing CIN [16–18]. These high-risk patients have a calculated incidence of CIN ranging from 10% to 30% [4, 18–20]. Pre-hydration is the primary intervention for preventing contrast nephropathy [18], but is not possible in the setting of emergency (primary) angioplasty procedures. The total contrast load during interventional procedures has been established as an independent predictor of CIN and could be effectively controlled by the operator during primary angioplasty cases [18, 21, 22]. Biplane imaging is commonly employed to minimise the contrast load, especially in patients with renal impairment and those who require primary coronary angioplasty procedures [1, 6, 7, 18, 23].Numerous studies have found that the radiation dose varies significantly according to tube angulations, particularly in the combination of steep left anterior oblique (LAO) with cranial or caudal angulations [24–27]. However, there are no published data on whether the radiation dose with biplane or single-plane imaging during coronary angioplasty differs between the three vascular territories: right coronary artery (RCA), left anterior descending (LAD) and left circumflex/intermediate (LCX). Furthermore, interventional cardiac procedures are operator dependent [28–30]. Hence, it was postulated that senior cardiologists would be more familiar with biplane equipment and thereby more able to reduce radiation dose, contrast load and procedural time than less experienced operators. To our knowledge, no studies have been published that compare the impact of biplane and single-plane imaging in coronary angioplasty procedures.The aims of this study were to determine whether biplane imaging reduces both contrast load and radiation dosage and shortens procedural time in patients undergoing primary or elective coronary angioplasty compared with single-plane imaging. We also investigated if there was a significant difference in radiation dose, contrast load and procedural time between biplane and single-plane imaging during coronary angioplasty in the three main vascular territories (RCA, LAD and LCX) and in procedures performed by operators with various levels of experience.     

Computerised analysis of osteoporotic bone patterns using texture parameters characterising bone architecture

Objective

To evaluate the geometric change of osteoporotic bone trabecular patterns using root mean square (RMS) values, first moment power spectrum (FMP) values and fractal dimension values. With the use of these methods, we attempted computerised analysis of osteoporotic bone patterns using texture parameters characterising bone architecture and computer-aided diagnosis of osteoporosis.

Methods

32 patient cases from Korea University Guro Hospital were analysed. Patient ages ranged from 51 to 89 years, with a mean age of 65 years. Receiver operating characteristic curve analysis was performed with determination of the area under the curve (AUC).

Results

The bone mineral density (BMD) measurement (AUC=0.78) was a better indicator of bone quantity than the RMS, FMP and fractal dimension values (AUC=0.72) for diagnosis; therefore the combination of RMS, FMP and fractal dimension values was a better indicator of bone quality.

Conclusion

Measurements that combined BMD measurement and RMS values and combined FMP and fractal dimension values (AUC=0.85) together produced better results than the use of the two parameter sets separately for a diagnosis of osteoporosis.

Advances in knowledge

For more effective application, additional study on more cases and data will be required.Osteoporosis is a condition in which the decreases in bone strength and density ultimately lead to fragile bones and subsequent fractures. Osteoporosis has been recognised as an established and well-defined disease that affects >75 million people in USA, Europe and Japan, and causes >4.5 million fractures annually in the USA and Europe [1].Osteoporosis does not only cause fractures, it also results in elderly subjects becoming bedridden with potentially life-threatening secondary complications. Since osteoporosis also causes back pain and loss of height, prevention of the disease and its associated fractures is essential in order to maintain health, quality of life and independence among the elderly [2].There are commonly used methods in diagnosing osteoporosis. The most widely utilised method to assess the bone mass is the determination of bone mineral density (BMD). This method is readily available and popular for its non-invasive means to identify osteoporosis in a patient. BMD is only one contributor towards determining bone strength and fracture risk reduction. In fact, BMD by dual-energy X-ray absorptiometry (DXA) is widely used for diagnosing osteoporosis. The World Health Organization (WHO) defines osteoporosis as a BMD that is 2.5 standard deviations (SD) or more below the mean of a young adult of the same sex (T-score) [3,4].Although the use of BMD is becoming much more frequent, there are several key concerns that need to be addressed before this method of diagnosis is undertaken. Routine DXA scanning sporadically identifies individuals with extremely high BMDs, which are not always explained by artefactual causes such as osteoarthritis (OA), the syndesmophytes of ankylosing spondylitis or surgically implanted metalwork. Paget''s disease, certain malignancies and rare conditions such as myelofibrosis and hepatitis C osteosclerosis can also raise BMD [5-8].Heterogeneity of density due to osteoarthritis or a previous fracture can often be detected on a scan, and can sometimes be excluded from the analysis [3]. Because of osteoarthritis, features such as soft-tissue calcification, the presence of overlying metal objects, or the presence of compression fractures and previous fractures, it can be difficult to diagnose osteoporosis using only DXA.The other diagnostic method for both osteoporosis and the assessment of bone mass is through the use of radiography. In this procedure, the Jikei University classification or Itami index is used [9], which radiographically classifies the stage of bone loss in a vertebral body (Figure 1). Approximately 25% of the vertebral bodies classified as first stage based on the Itami index, 60% of the vertebral bodies classified as second stage and 90% of the vertebral bodies classified as third stage have been reported to have suffered traumatic fractures.Open in a separate windowFigure 1(a) Normal: there are dense trabecular patterns in both the horizontal and vertical direction. (b) Early stage: bone images become lower in clarity and trabeculae become thinner. (c) First stage: trabeculae decrease in the horizontal direction and become more isolated in the vertical direction. (d) Second stage: in the horizontal direction, trabeculae continue to decrease. Also, in the vertical direction, they become thinner. (e) Third stage: trabeculae become distinguishable in both the horizontal and vertical direction. Bone images appear blurred. Scheme and details of the Jikei University classification or Itami index, which classifies radiographically the stage of bone loss in a vertebral body. Source: Itami and Ohata [9].Caligiuri et al [10] previously reported that using computerised radiographic methods to evaluate bone structure, such as fractal analysis, might be more helpful to determine fracture risk in osteoporosis. Takigawa et al [11] quantitatively evaluated trabecular patterns by spectral analysis of the patterns on lateral views of the lumbar vertebrae. Ishida et al [12,13] evaluated the patterns of power spectra with a two-dimensional fast Fourier transform (2DFFT) and a one-dimensional maximum entropy method (1DMEM). Nishihara et al [14] developed an algorithm that distinguished the central part of the vertebral body using abdominal X-ray CT images in order to determine whether it was possible to aid in the diagnosis of osteoporosis. Dougherty and Henebry [15] reported that the maximum deviation of the lacunarity from a neutral (fractal) model used with bone mineral density may have diagnostic value in characterising osteoporosis and predicting fracture risk. Ito et al [16] reported that vertebral microarchitecture can be visualised through multidetector CT (MDCT), and that microstructure parameters obtained by MDCT, together with volumetric BMD, provide better diagnostic performance for assessing fracture risk than DXA measurement. Recent studies have demonstrated that microarchitectural measurements acquired using high-resolution MDCT imaging available in vivo correlate strongly with those assessed using high-resolution peripheral quantitative CT [17,18].In this paper, we have attempted to evaluate the geometric change of trabecular patterns using root mean square (RMS), first moment power spectrum (FMP) and fractal dimension.     

Primary vaginal cancer: role of MRI in diagnosis,staging and treatment

Primary carcinoma of the vagina is rare, accounting for 1–3% of all gynaecological malignancies. MRI has an increasing role in diagnosis, staging, treatment and assessment of complications in gynaecologic malignancy. In this review, we illustrate the utility of MRI in patients with primary vaginal cancer and highlight key aspects of staging, treatment, recurrence and complications.The incidence of primary vaginal cancer increases with age, with approximately 50% of patients presenting at age greater than 70 years and 20% greater than 80 years.¹ Around 2890 patients are currently diagnosed with vaginal carcinoma in the USA each year, and almost 30% die of the disease.² The precursor for vaginal cancer, vaginal intraepithelial neoplasia (VAIN) and invasive vaginal cancer is strongly associated with human papillomavirus (HPV) infection (93%).^3,4 In situ and invasive vaginal cancer share many of the same risk factors as cervical cancer, such as tobacco use, younger age at coitarche, HPV and multiple sexual partners.^5–7 In fact, higher rates of vaginal cancer are observed in patients with a previous diagnosis of cervical cancer or cervical intraepithelial neoplasia.^7,8As is true for other gynaecologic malignancies, vaginal cancer diagnosis and staging rely primarily on clinical evaluation by the International Federation of Gynecology and Obstetrics (FIGO).⁹ Pelvic examination continues to be the most important tool for evaluating local extent of disease, but this method alone is limited in its ability to detect lymphadenopathy and the extent of tumour infiltration. Hence, FIGO encourages the use of imaging. Fluorine-18 fludeoxyglucose-positron emission tomography (¹⁸F-FDG-PET), a standard imaging tool for staging and follow-up in cervical cancer, can also be used for vaginal tumours, with improved sensitivity for nodal involvement compared to CT alone.¹⁰ In addition to staging for nodal and distant disease, CT [simulation with three dimensional (3D) conformations] is particularly useful for treatment planning and delivery of external beam radiation. MRI, with its excellent soft tissue resolution, is commonly used in gynaecologic malignancies and has been shown to be accurate in diagnosis, local staging and spread of disease in vaginal cancer.^11,12 While no formal studies are available for vaginal cancer, in cervical cancer MRI actually alters the stage in almost 30% of patients.^13–15Treatment planning in primary vaginal cancer is complex and requires a detailed understanding of the extent of disease. Because vaginal cancer is rare, treatment plans remain less well defined, often individualized and extrapolated from institutional experience and outcomes in cervical cancer.^1,16–19 There is an increasing trend towards organ preservation and treatment strategies based on combined external beam radiation and brachytherapy, often with concurrent chemotherapy,^14,20,21 surgery being reserved for those with in situ or very early-stage disease.²² Increasing utilization of MR may provide superior delineation of tumour volume, both for initial staging and follow-up, to allow for better treatment planning.²³     

Accessory or additional renal arteries show no relevant effects on the width of the upper urinary tract: a 64-slice multidetector CT study in 1072 patients with 2132 kidneys

Objective

The aim of this study was to find out on an unselected patient group whether crossing vessels have an influence on the width of the renal pelvis and what independent predictors of these target variables exist.

Methods

In this cross-sectional study, 1072 patients with arterially contrasted CT scans were included. The 2132 kidneys were supplied by 2736 arteries.

Results

On the right side, there were 293 additional and accessory arteries in 286 patients, and on the left side there were 304 in 271 patients. 154 renal pelves were more than 15 mm wide. The greatest independent factor for hydronephrosis on one side was hydronephrosis on the contralateral side (p<0.0001 each). Independent predictors for the width of the renal pelvis on the right side were the width of the renal pelvis on the left, female gender, increasing age and height; for the left side, predictors were the width of the renal pelvis on the right, concrements, parapelvic cysts and great rotation of the upper pole of the kidney to dorsal. Crossing vessels had no influence on the development of hydronephrosis. Only anterior crossing vessels on the right side are associated with widening of the renal pelvis by 1 mm, without making it possible to identify the vessel as an independent factor in multivariate regression models.

Conclusion

The width of the renal pelvis on the contralateral side is the strongest independent predictor for hydronephrosis and the width of the renal pelvis. There is no link between crossing vessels and the width of the renal pelvis.Obstructions of the ureteropelvic junction (UPJ) can be caused by intrinsic or extrinsic factors [1]. Although there are no studies of this to date, crossing the UPJ by an aberrant crossing vessel is considered the most important [2] of the extrinsic factors [3]. Crossing vessels, which are thought to cause from 40% to over 50% of the extrinsic UPJ obstructions in adults [4, 5], are located ventral more often than dorsal to the UPJ. These are usually normal vessels of the lower pole segment [4, 6–9], which can be divided into additional renal arteries arising from the aorta, and accessoric renal arteries arising from branches of the aorta [10, 11]. The primary surgical therapy of choice is endoscopic endopyelotomy [12]. The success rate of 89–90% [12, 13] is thought to be noticeably poorer in patients with crossing vessels [12, 13]; however, this is not undisputed [14, 15]. Be that as it may, to prevent bleeding complications it is necessary to be familiar with the vascular situation around the UPJ prior to the procedure [3, 16–18]. CT angiography is used for this purpose, as it is highly accurate, quick to perform and shows all relevant anatomical structures in relation to one another [3, 19, 20]. The objective of this study was to determine whether or not there are vascular morphological patterns or other factors that influence the width of the renal collecting system, regardless of the definitions of hydronephrosis.     

Iron overload: accuracy of in-phase and out-of-phase MRI as a quick method to evaluate liver iron load in haematological malignancies and chronic liver disease

Objectives

The purpose of this prospective study was to evaluate the accuracy of in-phase and out-of-phase imaging to assess hepatic iron concentration in patients with haematological malignancies and chronic liver disease.

Methods

MRI-based hepatic iron concentration (M-HIC, μmol g^–1) was used as a reference standard. 42 patients suspected of having iron overload and 12 control subjects underwent 1.5 T in- and out-of-phase and M-HIC liver imaging. Two methods, semi-quantitative visual grading made by two independent readers and quantitative relative signal intensity (rSI) grading from the signal intensity differences of in-phase and out-of-phase images, were used. Statistical analyses were performed using the Spearman and Kruskal–Wallis tests, receiver operator curves and κ coefficients.

Results

The correlations between M-HIC and visual gradings of Reader 1 (r=0.9534, p<0.0001) and Reader 2 (r=0.9456, p<0.0001) were higher than the correlations of the rSI method (r=0.7719, p<0.0001). There was excellent agreement between the readers (weighted κ=0.9619). Both visual grading and rSI were similar in detecting liver iron overload: rSI had 84.85% sensitivity and 100% specificity; visual grading had 85% sensitivity and 100% specificity. The differences between the grades of visual grading were significant (p<0.0001) and the method was able to distinguish different degrees of iron overload at the threshold of 151 μmol g^–1 with 100% positive predictive value and negative predictive value.

Conclusion

Detection and grading of liver iron can be performed reliably with in-phase and out-of-phase imaging. Liver fat is a potential pitfall, which limits the use of rSI.Iron overload is a clinically recognised condition with variety of aetiologies and clinical manifestations [1-4]. Liver iron concentration correlates closely with the total body iron stores [5]. The excess iron accumulates mainly in the liver and the progressive accumulation of toxic iron can lead to organ failure if untreated [2,4]. Several diseases causing iron overload, such as transfusion-dependent anaemia, haematological malignancies, thalassaemia, haemochromatosis and chronic liver disease, result in a large number of patients with a potentially treatable iron overload [1,2,4].Several quantitative MRI methods for iron overload measurement by multiple sequences have been established, such as proportional signal intensity (SI) methods and proton transverse relaxation rates (R₂, R₂*) [4,6,7]. A gradient echo liver-to-muscle SI-based algorithm [8] has been widely validated and used for quantitative liver iron measurement [8-11]. MRI-based hepatic iron concentration (M-HIC, μmol g^–1 liver dry weight) with corresponding R₂* [9] can be calculated with this method which is a directly proportional linear iron indicator, virtually independent of the fat fraction, as the echo times are taken in-phase [8,9]. This method showed a high accuracy in calibrations with the biochemical analysis of liver biopsies (3–375 μmol g^–1) of 174 patients. The mean difference of 0.8 μmol g^–1 (95% confidence interval of –6.3 to 7.9) between this method and the biochemical analysis is quite similar [8] to the intra-individual variability found in histological samples [12].The quantitative MRI methods are based on progressive SI decay, with the longer echo times due to relaxing properties of iron. Interestingly, this iron-induced effect is seen in MR images with multiple echoes [4,6-11], but also in dual-echo images, namely in-phase and out-of-phase imaging [13,14]. In-phase and out-of-phase imaging has become a routine part of liver MRI, performed initially for liver fat detection [6,13,15]. Quite recently some investigators have noticed an alternative approach of the sequence to detect liver iron overload due to the more pronounced SI decrease on in-phase images with the longer echo time [13,14]. Yet, to our knowledge, this is the first prospective study evaluating the accuracy of in-phase and out-of-phase imaging to assess hepatic iron concentration.The purpose of the study was to evaluate the capability and accuracy of dual-echo in-phase and out-of-phase imaging to assess hepatic iron concentration at 1.5 T in patients with haematological malignancies and chronic liver disease. MRI-based hepatic iron concentration (M-HIC, μmol g^–1) was used as a reference standard [8,9].     

Post-cholecystectomy syndrome: spectrum of biliary findings at magnetic resonance cholangiopancreatography

Post-cholecystectomy syndrome (PCS) is defined as a complex of heterogeneous symptoms, consisting of upper abdominal pain and dyspepsia, which recur and/or persist after cholecystectomy. Nevertheless, this term is inaccurate, as it encompasses biliary and non-biliary disorders, possibly unrelated to cholecystectomy. Biliary manifestations of PCS may occur early in the post-operative period, usually because of incomplete surgery (retained calculi in the cystic duct remnant or in the common bile duct) or operative complications, such as bile duct injury and/or bile leakage. A later onset is commonly caused by inflammatory scarring strictures involving the sphincter of Oddi or the common bile duct, recurrent calculi or biliary dyskinesia. The traditional imaging approach for PCS has involved ultrasound and/or CT followed by direct cholangiography, whereas manometry of the sphincter of Oddi and biliary scintigraphy have been reserved for cases of biliary dyskinesia. Because of its capability to provide non-invasive high-quality visualisation of the biliary tract, magnetic resonance cholangiopancreatography (MRCP) has been advocated as a reliable imaging tool for assessing patients with suspected PCS and for guiding management decisions. This paper illustrates the rationale for using MRCP, together with the main MRCP biliary findings and diagnostic pitfalls.Post-cholecystectomy syndrome (PCS) consists of a group of abdominal symptoms that recur and/or persist after cholecystectomy [1, 2]. It is defined as early if occurring in the post-operative period and late if it manifests after months or years.Although this term is used widely, it is not completely accurate, as it includes a large number of disorders, both biliary (1, 2]. It has been reported that ∼50% of these patients suffer from organic pancreaticobiliary and/or gastrointestinal disorders, whereas the remaining patients are affected by psychosomatic or extra-intestinal diseases. Moreover, in 5% of patients who undergo laparoscopic cholecystectomy, the reason for chronic abdominal pain remains unknown [1]. Probably because of the uncertainty in nosographic definition, the reported prevalence of PCS ranges from very low [2] to 47% [1]. Symptoms include biliary or non-biliary-like abdominal pain, dyspepsia, vomiting, gastrointestinal disorders and jaundice, with or without fever and cholangitis [1, 2]. Severe symptoms are more likely to represent a complication of cholecystectomy if they occur early or to express a definite treatable cause when compared with non-specific, dyspeptic or mild symptoms. A non-biliary aetiology of PCS should be suspected if no calculi or gallbladder abnormalities are found at cholecystectomy and symptoms are similar to those suffered pre-operatively [1]. Treatment for PCS is tailored to the specific cause and includes medication, sphincterotomy, biliary stenting, percutaneous drainage of bilomas and surgical revision for severe strictures [1–4].

Table 1

Main biliary causes of post-cholecystectomy syndrome (PCS) related to cholecystectomy. (Biliary malignancies are the most frequent causes of PCS unrelated to cholecystectomy [1])

Towards clinical assessment of velopharyngeal closure using MRI: evaluation of real-time MRI sequences at 1.5 and 3 T

Objective

The objective of this study was to demonstrate soft palate MRI at 1.5 and 3 T with high temporal resolution on clinical scanners.

Methods

Six volunteers were imaged while speaking, using both four real-time steady-state free-precession (SSFP) sequences at 3 T and four balanced SSFP (bSSFP) at 1.5 T. Temporal resolution was 9–20 frames s⁻¹ (fps), spatial resolution 1.6×1.6×10.0–2.7×2.7×10.0 mm³. Simultaneous audio was recorded. Signal-to-noise ratio (SNR), palate thickness and image quality score (1–4, non-diagnostic–excellent) were evaluated.

Results

SNR was higher at 3 T than 1.5 T in the relaxed palate (nasal breathing position) and reduced in the elevated palate at 3 T, but not 1.5 T. Image quality was not significantly different between field strengths or sequences (p=NS). At 3 T, 40% acquisitions scored 2 and 56% scored 3. Most 1.5 T acquisitions scored 1 (19%) or 4 (46%). Image quality was more dependent on subject or field than sequence. SNR in static images was highest with 1.9×1.9×10.0 mm³ resolution (10 fps) and measured palate thickness was similar (p=NS) to that at the highest resolution (1.6×1.6×10.0 mm³). SNR in intensity–time plots through the soft palate was highest with 2.7×2.7×10.0 mm³ resolution (20 fps).

Conclusions

At 3 T, SSFP images are of a reliable quality, but 1.5 T bSSFP images are often better. For geometric measurements, temporal should be traded for spatial resolution (1.9×1.9×10.0 mm³, 10 fps). For assessment of motion, temporal should be prioritised over spatial resolution (2.7×2.7×10.0 mm³, 20 fps).

Advances in knowledge

Diagnostic quality real-time soft palate MRI is possible using clinical scanners and optimised protocols have been developed. 3 T SSFP imaging is reliable, but 1.5 T bSSFP often produces better images.Approximately 450 babies born in the UK every year have an orofacial cleft [1], the majority of which include the palate [2]. While a cleft palate is commonly repaired surgically at around 6 months [3], residual velopharyngeal insufficiencies require follow-up surgery in 15–50% of cases [4]. This residual defect results in an incomplete closure of the velopharyngeal port, which in turns leads to hypernasal speech. Assessment of velopharyngeal closure in speech therapy is commonly performed using X-ray videofluoroscopy or nasendoscopy [5,6]. While nasendoscopy is only minimally invasive, it may be uncomfortable and provides only an en face view of the velopharyngeal port. In contrast, X-ray videofluoroscopy is non-invasive and produces an image which is a projection of the target anatomy. Additional information may be obtained from projections at multiple angles [5,7], but anatomical structures may overlie each other. Furthermore, soft tissue contrast, such as that from the soft palate, is poor, although it may be improved using a barium contrast agent coating [8] at the expense of making the procedure more invasive and unpleasant. Arguably the greatest drawback of X-ray videofluoroscopy is the associated ionising radiation dose, which carries increased risk in paediatric patients [9].An increasing number of research studies have used MRI to image the soft palate [10-13] and upper vocal tract [14-17]. In contrast to X-ray videofluoroscopy and nasendoscopy, MRI provides tomographic images in any plane with flexible tissue contrast. As a result, MRI has been used to obtain images of the musculature of the palate at rest and during sustained phonation [10,18,19]. It has also been used to image the whole vocal tract at rest or during sustained phonation [20-27] and with a single mid-sagittal image dynamically during speech [13,15-17,28-35].For assessment of velopharyngeal closure, dynamic imaging with sufficient temporal resolution and simultaneous audio recording is required. Audio recording during imaging is complicated by the loud noise of the MRI scanner, and both the safety risk and image degradation caused by using an electronic microphone within the magnet. As a result, optical fibre-based equipment with noise cancellation algorithms must be used [36].In order to fully resolve soft palate motion, Narayanan et al [30] suggested that a minimum temporal resolution of 20 frames s⁻¹ (fps) is required. A similar conclusion was reached by Bae et al [13], based on measurements of soft palate motion extracted from X-ray videofluoroscopy. Using segmented MRI, Inoue et al [35] demonstrated that changes in the velar position that were evident at acquired frame rates of 33 fps were not observed at 8 fps. However, MRI is traditionally seen as a slow imaging modality and achieving sufficient temporal resolution at an acceptable spatial resolution is challenging. Furthermore, as the soft palate is bordered on both sides by air, the associated changes in magnetic susceptibility at the interfaces make images prone to related artefacts.Dynamic MRI of the vocal tract has been performed using both segmented [17,33,37] and real-time acquisitions [13,15,16,28,31,38]. Segmented acquisitions [39] acquire only a fraction of the k-space data required for each image during one repetition of the test phrase and, hence, require multiple identical repetitions. While these segmented techniques permit high temporal and spatial resolutions [35], they require reproducible production of the same phrase up to 256 times [34], leading to subject fatigue. Differences between repeats of up to 95 ms in the onset of speech following a trigger have also been demonstrated [36].In contrast to segmented techniques, real-time dynamic methods permit imaging of natural speech, but require extremely rapid acquisition and often advanced reconstruction methods. The turbo spin echo (TSE) zoom technique [40] has been used to perform real-time MRI of the vocal tract [29,31] and is available as a clinical tool. The zoom technique excites a reduced field of view in the phase encode direction, hence allowing a smaller acquisition matrix and shorter scan for a constant spatial resolution. While such spin echo-based techniques are less susceptible to magnetic field inhomogeneity related signal dropout artefacts than other sequences, the frame rates achieved with these sequences are limited to 6 fps [31]. Gradient echo-based techniques have also been used to achieve similar temporal resolution [12,41,42] in the upper vocal tract, but are often used at much higher frame rates in other MRI applications such as cardiac imaging [43,44]. A number of gradient echo sequence variants exist. Fast low-angle shot (FLASH) type sequences [45] spoil any remaining transverse magnetisation at the end of every sequence repetition (TR). In contrast, steady-state free-precession (SSFP) sequences are not spoiled [46] and the remaining transverse magnetisation is used in the next TR to improve the signal-to-noise ratio (SNR), but renders the images sensitive to signal loss in the presence of motion. Balanced SSFP (bSSFP) sequences include additional gradients to bring the transverse magnetisation completely back into phase at the end of every TR [47,48]. The result is that bSSFP sequences have high SNR and are less sensitive to motion than SSFP sequences, but are more sensitive to field inhomogeneities, which cause bands of signal dropout.Both TSE and the gradient echo techniques discussed here sample in a rectilinear or Cartesian fashion, where one line of k-space is sampled in each echo. However, for real-time speech imaging, the highest acquired frame rates have been achieved by sampling k-space along a spiral trajectory [15,16,30,49]. While spiral imaging is an efficient way to sample k-space and is motion-resilient, it is prone to artefacts, particularly blurring caused by magnetic field inhomogeneities and off-resonance protons (i.e. fat) [50]. Recently, one group successfully used spiral imaging with multiple saturation bands and an alternating echo time (TE) to achieve an acquired real-time frame rate of 22 fps [13,16]. The saturation bands were used to allow a small field of view to be imaged without aliasing artefacts. The alternating TE was used to generate dynamic field maps which were incorporated into the reconstruction to compensate for magnetic field inhomogeneities. However, such advanced acquisition and reconstruction techniques are only available in a small number of research centres.The aim of this work is to optimise and demonstrate high-temporal-resolution real-time sequences available on routine clinical MRI scanners for assessment of soft palate motion and velopharyngeal closure. Consequently, radial and spiral acquisitions were excluded and the work focuses on Cartesian gradient echo sequences with parallel imaging techniques. As more clinical MRI departments now have 3 T scanners, imaging was performed at both 1.5 and 3 T to enable comparisons. At each field strength, we optimised sequences and implemented four combinations of spatial and temporal resolution in six subjects with simultaneous audio recordings.     

Miliary tuberculosis: a comparison of CT findings in HIV-seropositive and HIV-seronegative patients

The aim of this study was to determine the differences in CT findings of miliary tuberculosis in patients with and without HIV infection. Two radiologists reviewed retrospectively the CT findings of 15 HIV-seropositive and 14 HIV-seronegative patients with miliary tuberculosis. The decisions on the findings were reached by consensus. Statistical analysis was performed using the χ² test, Mann–Whitney U-test and Fisher''s exact test. All of the HIV-seropositive and -seronegative patients had small nodules and micronodules distributed randomly throughout both lungs. HIV-seropositive patients had a higher prevalence of interlobular septal thickening (p = 0.017), necrotic lymph nodes (p = 0.005) and extrathoracic involvement (p = 0.040). The seropositive patients had a lower prevalence of large nodules (p = 0.031). In conclusion, recognition of the differences in the radiological findings between HIV-seropositive and -seronegative patients may help in the establishment of an earlier diagnosis of immune status in patients with miliary tuberculosis.Miliary tuberculosis (TB), which results from lympho-haematogenous dissemination of Mycobacterium tuberculosis, is a complication of both primary and post-primary TB [1, 2]. This disease results in the formation of small discrete foci of granulomatous tissue, which are uniformly distributed throughout the lung [3].An increase in TB incidence, including miliary TB, has been associated with infection by human immunodeficiency virus (HIV) [4]. In 2005, the World Health Organization estimated that 12% of HIV deaths globally were caused by TB, and that there were 630 000 new co-infections with TB and HIV [5]. Disseminated TB accounted for 5.4–8.1% of culture-confirmed TB cases, with 10–14% of patients coinfected with HIV having clinically recognisable dissemination [6, 7].Chest radiography may be helpful in the detection and final diagnosis of miliary TB. The characteristic radiographical findings consist of the presence of fine granular or numerous small nodular opacities measuring 1–3 mm in diameter scattered throughout both lungs [1, 3, 8, 9]. However, the radiograph may appear to be normal in the early stage of disease or in cases with nodules below the threshold of perceptibility; therefore, a diagnosis of miliary TB from chest radiographs can be difficult [10].Several studies have shown that CT imaging is more sensitive for the detection of parenchymal abnormalities in patients with AIDS who have active intrathoracic disease, and it has been suggested that CT may also be helpful in the differential diagnosis [11–14]. In addition, it has been reported that certain imaging techniques provided by multidetector-row CT are useful for the diagnosis of multiple micronodular infiltrative lung disease [15]. CT findings of miliary TB have been described in previous reports [16–18]; however, only a few studies on miliary TB in patients with HIV, particularly with reference to the CD4 count, have been reported [19, 20]. The radiographic manifestations of HIV-associated pulmonary TB are thought to be dependent upon the level of immunosuppression at the time of overt disease [21–23].The purpose of this study was to determine the differences in the CT findings of miliary TB for patients with and without HIV infection and to analyse any correlation between the CT features and the level of immunosuppression in patients.