Bone age assessment by dual-energy X-ray absorptiometry in children: an alternative for X-ray?

Objective

The aim of the study was to validate dual-energy X-ray absorptiometry (DXA) as a method to assess bone age in children.

Methods

Paired dual-energy X-ray absorptiometry (DXA) scans and X-rays of the left hand were performed in 95 children who attended the paediatric endocrinology outpatient clinic of University Hospital Rotterdam, the Netherlands. We compared bone age assessments by DXA scan with those performed by X-ray. Bone age assessment was performed by two blinded observers according to the reference method of Greulich and Pyle. Intra-observer and interobserver reproducibility were investigated using the intraclass correlation coefficient (ICC), and agreement was tested using Bland and Altman plots.

Results

The intra-observer ICCs for both observers were 0.997 and 0.991 for X-ray and 0.993 and 0.987 for DXA assessments. The interobserver ICC was 0.993 and 0.991 for X-ray and DXA assessments, respectively. The mean difference between bone age assessed by X-ray and DXA was 0.11 years. The limits of agreement ranged from −0.82 to 1.05 years, which means that 95% of all differences between the methods were covered by this range.

Conclusions

Results of bone age assessment by DXA scan are similar to those obtained by X-ray. The DXA method seems to be an alternative for assessing bone age in a paediatric hospital-based population.Children with the same chronological age often have a different bone maturation as a consequence of various genetic and social factors [1-3]. Bone age is a useful indicator of children’s growth and biological maturation and is frequently assessed in paediatric endocrinology to determine delayed or advanced growth [4-7]. In children with growth disorders, regular hand X-rays are needed to follow skeletal development at an interval of once or twice per year [8-10]. The classical method to assess bone age is based on the recognition of changes in the maturity indicators in hand–wrist X-rays by comparison with a reference atlas (Greulich and Pyle method) [11].The main problem with this method is the exposure to a certain amount of irradiation involved in X-ray procedures [12-14]. Although the precise risk estimate of paediatric cancers due to diagnostic X-ray exposure is not known [15-17], we know that the lifetime attributable risk of cancer due to one single X-ray exposure in childhood approximates 15% per sievert [18]. To avoid detrimental effects in later life as a result of cumulative radiation exposure, dose reduction is therefore particularly important in childhood [18,19]. Consequently, methods involving less radiation would be preferable to assess bone age in children. Dual-energy X-ray absorptiometry (DXA) has been suggested as a safer method to assess bone age [20]. In both children and adults, DXA is currently widely used to measure bone mineral density for the assessment of osteoporosis [21]. When applied to assess bone age, a hand–wrist scan by DXA (0.0001 mSv) produces a 10-fold lower effective dose than a hand–wrist X-ray (0.001 mSv) [22].One previous study in a paediatric population of 60 Polish subjects (5–20 years old) suggested that results for bone age assessment by DXA are similar to those produced by X-ray [20]. However, their results were presented as correlation coefficients and t-test analysis. For methods of comparison, Bland and Altman analysis is a more appropriate analysis, since it investigates agreement [23,24]. Also, they used a reference method that applied to the Polish population [25], whereas the Greulich and Pyle method would be more generalisable [3].Thus far, the accuracy of the assessment of bone age in children using DXA scans has not been properly validated. Therefore, the aim of this study was to investigate whether hand–wrist bone age assessment by DXA produces similar results to the classical X-ray method.     

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].     

Sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach in the lumbar region

Objectives

The use of ultrasound to guide peripheral nerve blocks is now a well-established technique in regional anaesthesia. However, despite reports of ultrasound guided epidural access via the paramedian approach, there are limited data on the use of ultrasound for central neuraxial blocks, which may be due to a poor understanding of spinal sonoanatomy. The aim of this study was to define the sonoanatomy of the lumbar spine relevant for central neuraxial blocks via the paramedian approach.

Methods

The sonoanatomy of the lumbar spine relevant for central neuraxial blocks via the paramedian approach was defined using a “water-based spine phantom”, young volunteers and anatomical slices rendered from the Visible Human Project data set.

Results

The water-based spine phantom was a simple model to study the sonoanatomy of the osseous elements of the lumbar spine. Each osseous element of the lumbar spine, in the spine phantom, produced a “signature pattern” on the paramedian sagittal scans, which was comparable to its sonographic appearance in vivo. In the volunteers, despite the narrow acoustic window, the ultrasound visibility of the neuraxial structures at the L3/L4 and L4/L5 lumbar intervertebral spaces was good, and we were able to delineate the sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach.

Conclusion

Using a simple water-based spine phantom, volunteer scans and anatomical slices from the Visible Human Project (cadaver) we have described the sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach in the lumbar region.Ultrasound is frequently used to guide central venous cannulation [1] and peripheral nerve blocks [2,3]. However, published data suggest that it is rarely used for imaging the spine or for central neuraxial blocks (CNBs; epidural and spinal injections) [4], which is surprising considering that there are data suggesting that an ultrasound examination prior to epidural access (pre-puncture scan, preview scan or scout scan) improves technical [5-7] and clinical [7,8] outcomes and also the learning curve of obstetric epidural anaesthesia [9]. Despite these encouraging results, we believe that there are very few anaesthetists who currently perform a preview scan prior to epidural catheterisation [5,7] or real-time ultrasound-guided (USG) CNBs [6,10]. This is quite interesting considering that emergency physicians are able to interpret ultrasound images of the spine [11] and are performing lumbar puncture using ultrasound in the accident and emergency department [11,12]. Reasons for this paucity of data or a lack of interest in USG CNBs in regional anaesthesia are not clear, but the authors believe it may be due to a lack of understanding of spinal sonoanatomy. The aim of this study was to describe the sonoanatomy relevant for USG CNBs via the paramedian approach in the lumbar region.     

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.     

Subcutaneous panniculitis-like T-cell lymphoma with breast involvement: functional and morphological imaging findings

Panniculitis-like T-cell lymphoma is a very uncommon subtype of cutaneous T-cell lymphomas. In this case report, we describe the morphological (CT and MRI) and functional (¹⁸F-FDG-PET and bone scan) imaging findings in a 35-year-old patient who suffered from slowly progressing multiple subcutaneous lesions caused by this rare disease.According to the World Health Organization–European Organization for Research and Treatment of Cancer (WHO–EORTC) classification, subcutaneous panniculitis-like T-cell lymphomas (SPTCLs) belong to the group of cutaneous T-cell and natural killer (NK)-cell lymphomas [1]. Less than 1% of all non-Hodgkin lymphomas (NHLs) are SPTCLs. Recent studies differentiate distinct subtypes of SPTCL each with a different prognosis [2]. Only a few reports describe the imaging of primary cutaneous T-cell lymphomas [3–8], even fewer with the imaging of subcutaneous involvement in SPTCLs [4, 9–11]. In this case report, we describe panniculitis-like T-cell lymphoma as a very rare cause of unclear subcutaneous soft-tissue indurations. We detail the morphological and functional CT, MRI, ¹⁸F-FDG-PET and bone scan findings relating to multiple panniculitic lesions in a 35-year-old female patient suffering from this uncommon subgroup of lymphoma.     

Prostatic cancer surveillance following whole-gland high-intensity focused ultrasound: comparison of MRI and prostate-specific antigen for detection of residual or recurrent disease

Objective

This retrospective study compares dynamic contrast-enhanced (DCE) MRI with the serial prostate-specific antigen (PSA) measurement for detection of residual disease following whole-gland high-intensity focused ultrasound (HIFU) therapy of prostate cancer.

Methods

Patients in whom post-HIFU DCE-MRI was followed within 3 months by ultrasound-guided transrectal biopsy were selected from a local database. 26 patients met the study inclusion criteria. Serial PSA levels following HIFU and post-HIFU follow-up MRI were retrieved for each patient. Three radiologists unaware of other investigative results independently assessed post-HIFU MRI studies for the presence of cancer, scoring on a four-point scale (1, no disease; 2, probably no disease; 3, probably residual disease; and 4, residual disease). Sensitivity, specificity and receiver operating characteristic (ROC) analysis were performed for each reader, post-HIFU PSA nadir and pre-biopsy PSA level thresholds of >0.2 and >0.5 ng ml⁻¹.

Results

The sensitivity of DCE-MRI for detection of residual disease for the three readers ranged between 73% and 87%, and the specificity between 73% and 82%. There was good agreement between readers (κ=0.69–0.77). The sensitivity and specificity of PSA thresholds was 60–87% and 73–100%, respectively. The area under the ROC curve was greatest for pre-biopsy PSA (0.95).

Conclusion

DCE-MRI performed following whole-gland HIFU has similar sensitivity and specificity and ROC performance to serial PSA measurements for detection of residual or recurrent disease.High-intensity focused ultrasound (HIFU) is a promising alternative management paradigm for prostate cancer available to patients with organ-confined disease. Whole-gland treatment is achievable while sparing the neurovascular bundles and external urethral sphincter [1,2]. As a result, reported rates of urinary and sexual morbidity are lower and quality of life higher following HIFU therapy than following radical prostatectomy [3].However, recurrence rates as high as between 30% and 40% at 5 years have been reported [4]. Identification of potential residual or recurrent disease is therefore paramount, guiding administration of salvage therapy [5]. Accepted surveillance for residual or recurrent tumour following whole-gland HIFU is reliant on serial prostate-specific antigen (PSA) measurements followed by biopsy for patients with a high or rising PSA [6].There are several potential advantages of assessing post-HIFU residual disease with MRI. First, MRI may provide a more sensitive test than PSA, as it is able to detect disease not elevating PSA but causing a change in the MRI features of residual prostatic tissue. Second, when disease is detected on MRI, it is clear that imaging also provides the location of disease and therefore has the added advantage of being able to guide biopsy and salvage therapy. Finally, as primary focal treatment (e.g. hemi-ablation) of prostate cancer becomes established [7], it is highly likely that identification of residual disease by PSA alone will become more difficult, as PSA from untreated prostate may mask residual disease. Development of an imaging-based alternative for detection of residual or recurrent disease in the post-HIFU prostate is therefore necessary.Dynamic contrast-enhanced (DCE) MRI has been used for detection of cancer in the untreated prostate, and has performance characteristics similar to gland biopsy [8]. DCE-MRI has also been reported to detect residual disease after radiotherapy [9]. Moreover, early studies investigating DCE-MRI in patients treated with whole-gland HIFU have shown promising results for detection of residual tumour [6,10].Our study assesses the performance of DCE-MRI to detect residual or recurrent disease in the post-HIFU (whole-gland) prostate, and compares this with serial PSA measurement.     

Correlation between computerised findings and Newman's scaling on vascularity using power Doppler ultrasonography imaging and its predictive value in patients with plantar fasciitis

Objectives

The purpose of this study was to correlate findings on small vessel vascularity between computerised findings and Newman''s scaling using power Doppler ultrasonography (PDU) imaging and its predictive value in patients with plantar fasciitis.

Methods

PDU was performed on 44 patients (age range 30–66 years; mean age 48 years) with plantar fasciitis and 46 healthy subjects (age range 18–61 years; mean age 36 years). The vascularity was quantified using ultrasound images by a customised software program and graded by Newman''s grading scale. Vascular index (VI) was calculated from the software program as the ratio of the number of colour pixels to the total number of pixels within a standardised selected area of proximal plantar fascia. The 46 healthy subjects were examined on 2 occasions 7–10 days apart, and 18 of them were assessed by 2 examiners. Statistical analyses were performed using intraclass correlation coefficient and linear regression analysis.

Results

Good correlation was found between the averaged VI ratios and Newman''s qualitative scale (ρ = 0.70; p<0.001). Intratester and intertester reliability were 0.89 and 0.61, respectively. Furthermore, higher VI was correlated with less reduction in pain after physiotherapeutic intervention.

Conclusions

The computerised VI not only has a high level of concordance with the Newman grading scale but is also reliable in reflecting the vascularity of proximal plantar fascia, and can predict pain reduction after intervention. This index can be used to characterise the changes in vascularity of patients with plantar fasciitis, and it may also be helpful for evaluating treatment and monitoring the progress after intervention in future studies.Plantar fasciitis is the most common cause of heel pain, and about 2 000 000 patients in the USA receive treatment every year because of this condition [1]. Besides mechanical loading, vascular disturbance with consequent metabolic impairment and hypoxia is thought to play an important role [2]. Indeed, fibrovascular hyperplasia and vascular proliferation were observed from microscopic specimens obtained from operative resection [3-5]. Walther et al [6] were the first group to evaluate plantar fascia vascularity non-invasively using power Doppler ultrasonography (PDU).PDU is one of the colour flow imaging techniques that encodes the amplitude of the power spectral density of the Doppler signals [7]. This method has been used to assess soft-tissue vascularity and treatment efficacy with a variety of musculoskeletal and related problems. Changes in vascularity in synovial tissues in patients with rheumatoid arthritis [8-11], osteoarthritis [12,13], tendinopathy [6,14-21] and plantar fasciitis [6] have been reported. Modulation in vascularity was observed in patients with tendinopathy after a course of intervention [14-21]. Most of these studies used the Newman''s grading scale to grade the tissue vascularity [19-21]. This qualitative grading for the PDU images had high correlation with the histopathological grading of vascularity of the synovial membrane in patients with arthritis [11]. Nevertheless, Newman''s grading system may not be objective and sensitive enough to differentiate subtle vascularity changes.Recently, computerised methods were used to quantify tissue vascularity with ultrasonography. Tissue vascularity was quantified by computing a vascular index (VI), which is calculated as the ratio of the number of colour pixels to the total number of pixels within the region of interest in patients with soft-tissue problems [8,9,11,17]. Note that most of these studies were conducted using colour Doppler ultrasonography. In this connection, PDU is superior to frequency-based colour Doppler ultrasonography, especially in tissues with low blood flow, such as the plantar fascia [6,22,23]. Ying et al [24] reported the feasibility of computerised quantification of vascularity in thyroid tissues with PDU. We were interested in evaluating whether the computerised quantification of vascularity could be applied on musculoskeletal tissue, such as the plantar fascia. Therefore, the purpose of the present study was to correlate the computerised VI and Newman''s qualitative grading scale in quantifying plantar fascia vascularity using PDU, to evaluate the intra- and intertester reliability of the computerised quantitative method and its predictive ability of recovery in patients with plantar fasciitis. Proximal plantar fascia, which is the most commonly affected area in individuals with plantar fasciitis, according to clinical examination [25,26] and previous B-mode ultrasonography [26-28], was chosen as the target testing area.     

Pulmonary tuberculosis associated with the reversed halo sign on high-resolution CT

We describe the case of a 32-year-old woman with pulmonary tuberculosis in whom a high-resolution CT scan demonstrated the reversed halo sign. The diagnosis of tuberculosis was made by lung biopsy and the detection of acid-fast bacilli in the sputum smear and culture. Follow-up assessment revealed a significant improvement in the lesions.The reversed halo sign is observed on high-resolution CT (HRCT) as a focal round area of ground-glass attenuation surrounded by a crescent or ring of consolidation [1, 2]. It was first described as being relatively specific for cryptogenic organising pneumonia [1], but was later observed in several other infectious [3–5] and non-infectious [6, 7] diseases.We report a case of a 32-year-old patient with tuberculosis who exhibited the reversed halo sign on chest CT. To our knowledge, this sign has not been previously described in an adult with pulmonary tuberculosis.     

Pattern and predictors of volumetric change of parotid glands during intensity modulated radiotherapy

Objective:

To describe the pattern and predictors of volumetric change of parotid glands during intensity modulated radiotherapy (IMRT) for oropharyngeal cancer.

Methods:

A cohort of patients undergoing weekly CT scans during dose-painted IMRT was considered. The parotid glands were contoured at the time of treatment planning (baseline) and on all subsequent scans. For a given patient, the parotid glands were labelled as higher (H) and lower (L), based on the mean dose at planning. The volume of each gland was determined for each scan and the percent change from baseline computed. Data were fit to both linear and quadratic functions. The role of selected covariates was assessed with both logistic regression and pair-wise comparison between the sides. The analyses were performed considering the whole treatment duration or each separate half.

Results:

85 patients, 170 glands and 565 scans were analysed. For all parotids except one, the quadratic function provided a better fit than the linear one. Moreover, according to both the logistic regression and pair-wise comparison, the cumulative mean dose of radiation is independently correlated with the parotid shrinkage during the first but not the second half of the treatment. Conversely, age and weight loss are predictors of relative parotid shrinkage during the entire course of the treatment.

Conclusion:

Parotid gland shrinkage during IMRT is not linear. Age, weight loss and radiation dose independently predict parotid shrinkage during a course of IMRT.

Advances in knowledge:

The present study adds to the pathophysiology of parotid shrinkage during radiotherapy.Fractionated radiotherapy is based on the assumption that the dose distribution obtained at planning is delivered during each treatment session. However, both set-up errors and tissue deformation can modify the dose that is administered. Shifts in the location of isodose levels compared with planning become critical for techniques that are highly conformal to the target(s), such as IMRT, justifying the interest in image guidance and adaptive radiotherapy [1]. Because of the sharp dose gradient around the target(s), subtle changes in the relative position or in the volume of organs at risk may alter the planned dose that the volume of an organ receives, as has been shown for the parotid glands [2–6].In a study by Ricchetti et al [7], we found that the parotid glands are the regions of interest that undergo the largest absolute and relative changes in volume during treatments. Although at least 16 articles have documented a significant percent reduction in the volume of the parotid gland during the course of fractionated radiotherapy [2,3,7–20], there are still several unanswered questions. It is unclear why some parotid glands shrink to about 50–60% during treatment, while others show only minimal changes. Studies that have investigated predictors of shrinkage have suggested weight loss during treatment, patient age and dose of radiation to the parotid as potential factors [2,9,16–19]. However, results are inconsistent [3,8,10,14]. Some studies have suggested that dosimetrically spared parotid glands undergo only minimal volume changes during treatment [16,18], whereas others describe a similar behaviour regardless of the radiation dose [7,8,10]. Furthermore, it is unclear whether the daily percent volume change is constant [8,10,16,19] or variable [7,10,13] during the course of treatment. A variable daily percent change in the volume may indicate that there are predictive factors specific to certain portions of the fractionated radiation schedule. In the present article, we attempt to clarify these points.     

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.     

Compromised perfusion in femoral head in normal rats: distinctive perfusion MRI evidence of contrast washout delay

Objectives

The femoral head is prone to osteonecrosis. This study investigated dynamic contrast-enhanced (DCE) MRI contrast washout features of the femoral head and compared the data with data from other bony compartments in normal rats.

Methods

7-month-old Wistar rats were used. DCE MRI of the right hip (n=18), right knee (n=12) and lumbar spine (n=10) was performed after an intravenous bolus injection of Gd-DOTA (0.3 mmol kg^–1). Temporal resolution was 0.6 s for hip and spine, and 0.3 s for knee. The total scan duration was 8 min for hip and spine, and 4.5 min for knee. The regions of interest for enhancement measurement included femoral head, proximal femoral diaphysis, distal femoral diaphysis and epiphysis, proximal tibial epiphysis and diaphysis, and lumbar vertebrae L1–5.

Results

Femoral head showed no enhancement signal decay during the DCE MRI period, while all other bony compartments showed a contrast washin phase followed by a contrast washout phase. In the knee joint, the contrast washout of the proximal tibia diaphysis was slower that of other bony compartments of the knee.

Conclusion

Based on the evidence of delayed contrast washout, this study showed that blood perfusion in the femoral head could be compromised in normal rats.Clinical studies have shown that the femoral head has a poorer blood supply compared with the femoral neck and femoral shaft [1,2]. MRI-derived perfusion indices of maximum enhancement and enhancement slope for the femoral head were only about one-fifth to one-quarter of those for the femoral shaft in healthy elderly male and female subjects [1]. Because of the absence of an effective collateral circulation, the femoral head is at an especially high risk of ischaemic injury [3]. Osteonecrosis of the femoral head may be idiopathic or secondary to numerous diseases. Bone perfusion can affect bone metabolism and microdamage repair. Osteonecrosis can have early vascular components that change underlying bone perfusion in the affected bone and joint, and contribute to the clinical cascade of disease [4]. Relatively mild haemodynamic impairment, which may not necessarily compromise other sites, has the potential to cause osteonecrosis of the femoral head [1,5,6]. In animals, osteonecrosis of the femoral head is sporadically encountered in dogs [7]. Perthes disease-like necrosis of the femoral head and neck occurs in some breeds of small dogs [7]. Osteonecrosis of the femoral head is also seen in spontaneously hypertensive rats [8-10]. Recently it was reported that delayed washout in dynamic contrast-enhanced (DCE) MRI suggests compromised blood perfusion in the tissue, including blood stasis or outflow obstruction [11]. It was also reported that delayed contrast washout could be seen in sites of bone marrow oedema, osteoarthritis and avascular osteonecrosis [11]. This study investigated DCE MRI contrast washout features of the femoral head in normal mature rats. The results from the femoral head were compared with the data from proximal and distal femoral diaphysis, distal femoral epiphysis, proximal tibial epiphysis and diaphysis, and lumbar vertebral bodies.     

MRI manifestations of soft-tissue haemangiomas and accompanying reactive bone changes

Objectives

Soft tissue haemangiomas are common benign vascular lesions that can be accompanied by reactive changes in the adjacent bone structure. This study aimed to discuss the MRI features of soft-tissue haemangiomas with an emphasis on changes in bone.

Methods

The radiographic and MRI findings of 23 patients (9 males, 14 females; mean age 25 years; age range 2–46 years) with soft-tissue haemangiomas were analysed retrospectively. MR images were evaluated for location of the lesion, size, configuration, signal features, contrast patterns, proximity to adjacent bone and changes in the accompanying bone. Excisional biopsy was performed in 15 patients.

Results

Radiographs demonstrated phleboliths in 8 patients (34%) and reactive bone changes in 4 (19%). On MRI, T₁ weighted images showed that most of the lesions were isointense or isohyperintense, as compared with muscle tissue; however, on T₂ weighted images all lesions appeared as hyperintense. Following intravenous gadolinium-diethylene triamine pentaacetic acid (DTPA) administration, homogeneous enhancement was observed in 3 lesions and heterogeneous enhancement was seen in 19. No enhancement was observed in one patient. Bone atrophy adjacent to the lesion was observed in four patients.

Conclusion

MRI is the most valuable means of diagnosing deep soft-tissue haemangiomas. Bone changes can accompany deeply situated haemangiomas; in four of our patients, we found atrophy of the bone adjacent to the lesion. To our knowledge, this is the first report in the literature regarding atrophy of the bone adjacent to a lesion.Soft-tissue haemangioma, a frequently encountered benign vascular lesion, accounts for 7% of all benign soft-tissue tumours [1-5]. Such lesions can be cutaneous, subcutaneous, intramuscular or synovial [1]. Intramuscular haemangioma is rare and responsible for 0.8–1.8% of all haemangiomas [3,5,6]. Superficial haemangiomas are diagnosed easily because they cause discolorations of the skin; imaging techniques are rarely needed [1]. However, deep lesions are difficult to diagnose clinically, because they do not cause discolorations and grow slowly; imaging techniques are required to discriminate these deep haemangiomas from malignant lesions [1,2,7]. Bone changes accompanying haemangioma have been reported previously in the literature and include cortical thickening, erosion, medullary sclerosis, trabecular coarsening and hypertrophy [1,8]. Here, we present the MRI manifestations of soft-tissue haemangiomas and reactive changes to the neighbouring bones. To the best of our knowledge, this is the first report of its kind in the English literature.     

Diagnostic quality of 50 and 100 μm computed radiography compared with screen-film mammography in operative breast specimens

Objective

To compare reader ratings of the clinical diagnostic quality of 50 and 100 μm computed radiography (CR) systems with screen–film mammography (SFM) in operative specimens.

Methods

Mammograms of 57 fresh operative breast specimens were analysed by 10 readers. Exposures were made with identical position and compression with three mammographic systems (Fuji 100CR, 50CR and SFM). Images were anonymised and readers blinded to the CR system used. A five-point comparative scoring system (−2 to +2) was used to assess seven quality criteria and overall diagnostic value. Statistical analysis was subsequently performed of reader ratings (n=16 925).

Results

For most quality criteria, both CR systems were rated as equivalent to or better than SFM. The CR systems were significantly better at demonstrating skin edge and background tissue (p<1×10⁻⁵). Microcalcification was best demonstrated on the CR50 system (p<1×10⁻⁵). The overall diagnostic value of both CR systems was rated as being as good as or better than SFM (p<1×10⁻⁵).

Conclusion

In this clinical setting, the overall diagnostic performance of both CR systems was as good as or better than SFM, with the CR50 system performing better than the CR100.There are currently three technologies widely available for diagnostic mammography: screen–film mammography (SFM) and two forms of large-field digital mammography [1]. The use of the term full-field digital mammography (FFDM) varies in the published literature and has been applied to both computed radiography (CR) and direct digital radiography (DR). Small-field digital mammography (SFDM) is mainly used for imaging during stereotactic biopsy [2].The advantages of digital mammography over SFM include: improved sensitivity in dense breast tissue, reduced radiation dose, the ability to manipulate images for review, and digital storage and retrieval methods [3]. CR was the earliest digital system in use. Imaging cassettes contain a re-useable photostimulable phosphor, replacing the traditional screen–film cassettes, and are then transferred to a laser reader. DR has an in-built detector and reader. Digital mammography has a lower spatial resolution than SFM, but has a very high contrast resolution. This allows the overall resolution of digital mammography to be at least equivalent to SFM [4-8], even when viewing calcification smaller than the pixel size [9]. Some CR systems have not met the quality standards of a number of governing bodies for mammography, including the European Network of Reference Assessment Centres (EUREF) and the NHS Breast Screening Programme (NHSBSP) [10,11]. This is related to the resolution achievable with 100 µm cassettes [12]. It is now known that CR systems using 50 µm cassettes can provide improved resolution, at an acceptable mean glandular dose, and have been approved for screening by the NHSBSP [13-15].Phantom studies indicate that the resolution and performance of DR are greater than those of CR [16,17], but have limitations. Although there are many clinical studies comparing the performance of DR and SFM [4-7,9,18-26], there are fewer that compare CR with SFM or DR [8,25,27-32]. We sought a method to compare the clinical diagnostic quality of two types of CR technology with that of SFM. We chose to study surgical specimens of breast tissue, which, although not absolutely comparable to in vivo mammography, allows realistic testing of image quality. In addition, multiple exposures can be obtained in reproducible conditions without irradiating the patient.     

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.     

Hepatocellular carcinoma in cirrhotic patients at multidetector CT: hepatic venous phase versus delayed phase for the detection of tumour washout

Objectives

Our aim was to compare retrospectively hepatic venous and delayed phase images for the detection of tumour washout during multiphasic multidetector row CT (MDCT) of the liver in patients with hepatocellular carcinoma (HCC).

Methods

30 cirrhotic patients underwent multiphasic MDCT in the 90 days before liver transplantation. MDCT was performed before contrast medium administration and during hepatic arterial hepatic venous and delayed phases, images were obtained at 12, 55 and 120 s after trigger threshold. Two radiologists qualitatively evaluated images for lesion attenuation. Tumour washout was evaluated subjectively and objectively. Tumour-to-liver contrast (TLC) was measured for all pathologically proven HCCs.

Results

48 HCCs were detected at MDCT. 46 of the 48 tumours (96%) appeared as either hyper- or isoattenuating during the hepatic arterial phase subjective washout was present in 15 HCCs (33%) during the hepatic venous phase and in 35 (76%) during the delayed phase (p<0.001, McNemar’s test). Objective washout was present in 30 of the 46 HCCs (65%) during the hepatic venous phase and in 42 of the HCCs (91%) during the delayed phase (p=0.001). The delayed phase yielded significantly higher mean TLC absolute values compared with the hepatic venous phase (−16.1±10.8 HU vs −10.5±10.2 HU; p<0.001).

Conclusions

The delayed phase is superior to the hepatic venous phase for detection of tumour washout of pathologically proven HCC in cirrhotic patients.Multiphasic contrast-enhanced multidetector row CT (MDCT) plays a pivotal role in the diagnostic work-up of cirrhotic patients, who are at increased risk of developing hepatocellular carcinoma (HCC) [1]. Increased enhancement of the tumour compared with the surrounding liver parenchyma during the hepatic arterial phase is the cornerstone for the diagnosis of HCC at multiphasic MDCT [1,2]. However, a variety of entities—dysplastic nodules [3], confluent hepatic fibrosis [4], non-tumourous arterioportal shunts [5] and haemangioma [6]—can also manifest with increased arterial enhancement and thus mimic HCC, particularly if they are smaller than 2 cm in diameter.Tumour washout, i.e. hypoattenuation relative to the adjacent hepatic parenchyma during the hepatic venous or delayed phase, has been recognised as a strong predictor of HCC [7,8]. This sign has been included, along with the presence of hypervascularity, in the latest American Association for the Study of Liver Diseases (AASLD) guidelines for the diagnosis of HCC at multiphasic MDCT, MRI or contrast-enhanced ultrasonography [1]. Although it is well known that tumour enhancement is best visualised during the late hepatic arterial phase [9,10], there is no consensus regarding the correct timing for the detection of tumour washout at multiphasic MDCT of the liver. Most commonly, the hepatic arterial phase is followed by the hepatic venous phase, acquired 60–70 s after injection of contrast material [9-12]. In addition, a delayed phase, acquired from 2–10 min after contrast material injection, can follow the hepatic venous phase [13-20] or can occur alone after the hepatic arterial phase [21-23]. Regardless of the phase sequence chosen, to the best of our knowledge, no study has yet compared the hepatic venous and delayed phases for the detection of tumour washout in patients with HCC. The purpose of our study was to compare retrospectively the hepatic venous and delayed phases for the detection of tumour washout during multiphasic MDCT of the liver in patients with HCC who underwent liver transplantation.     

Contrast-enhanced ultrasonography of hepatocellular carcinoma: correlation between quantitative parameters and histological grading

Objective

The quantitative parameters in the contrast-enhanced ultrasonography time–intensity curve of hepatocellular carcinoma (HCC) were studied to explore their possible implication for histological grading of HCC.

Methods

A total of 130 HCC patients (115 males and 15 females; age: 48.13±11.00 years) were studied using contrast-enhanced ultrasonography time–intensity curve and histological pathology. The quantification software Sonoliver® (TomTec Imaging Systems, Unterschleissheim, Germany) was applied to derive time–intensity curves of regions of interest in the interior of HCCs and in reference. Quantitative parameters of 115 patients were successfully obtained, including maximum of intensity (IMAX), rise time (RT), time to peak (TTP), rise slope (RS) and washout time (WT). Histological grading of HCC was performed using haematoxylin–eosin staining, and monoclonal antibodies specific for smooth muscle actin were used to observe unpaired arteries (UAs).

Results

There were significant differences among WTs in the three differentiated HCC groups (p<0.05). However, there were no significant differences among RT, TTP, RS and IMAX in the differentiated HCC groups. Moreover, the number of UAs in the differentiated HCC groups showed no statistical significance.

Conclusion

WT plays an important role in predicting well, moderately and poorly differentiated HCC.The majority of hepatocellular carcinomas (HCCs) develop through multistep hepatocarcinogenesis [1]. Various types of hepatocellular nodules are seen in cirrhotic livers. The International Working Party of the World Congress of Gastroenterology classifies hepatocellular nodules into six types: regenerative nodules, low-grade dysplastic nodules, high-grade dysplastic nodules, well-differentiated HCC, moderately differentiated HCC and poorly differentiated HCC. The histopathological grades and types constitute well-established prognostic factors [2]. Thus, early diagnosis and confirmation of the type of hepatocellular nodules present and cellular differentiation before treatment are important.Although definite differentiation among HCC by imaging is usually impossible, the relationship between tumour cellular differentiation and image findings has been studied using contrast-enhanced (CE) CT, CEMRI and CE ultrasonography (CEUS). Tumour pathological differentiation correlates well with image findings [,3−8].Dynamic CEUS during the past decade has noticeably improved the detection and characterisation of focal liver lesions [9]. A previous study showed that CEUS and spiral CT provided a similar diagnostic accuracy in the characterisation of focal liver lesion [10]. The appearance of HCC on CEUS has also been described well. Current low-mechanical-index techniques for CEUS using second-generation microbubble agents have advantages in characterising HCC, including real-time demonstration of continuous haemodynamic changes in both the liver and hepatocellular nodules. Some studies postulated that variations of enhancement patterns may be related to the pathological function of HCC [,5−8]. Moderately differentiated HCCs generally show classic enhancement features, with presence of hypervascularity in the arterial phase and washout during the portal phase, whereas well and poorly differentiated tumours account for most atypical variations in the arterial phase and portal venous phase [7].Reports assessing hepatocellular nodules have been based on visual analysis, despite the disadvantages of interobserver variability and low reproducibility of results. Although quantitative analysis CEUS perfusion provides more objective, reliable and reproducible results [11], the time–intensity curve (TIC) of CEUS has been obtained by quantification software for offline analysis [,12−14], from which a series of semi-quantitative perfusion parameters is extracted and analysed. An analysis of the parameters of TIC in HCC has proven the correlation of CEUS with unpaired arteries (UAs) in HCC [14]. In the present study, we compare the quantitative parameters in CEUS and UAs in different pathological gradings of HCCs to explore their possible implication for histological grading of HCC.     

Quality assurance of dynamic parameters in volumetric modulated arc therapy

Objectives

The purpose of this study was to demonstrate quality assurance checks for accuracy of gantry speed and position, dose rate and multileaf collimator (MLC) speed and position for a volumetric modulated arc treatment (VMAT) modality (Synergy® S; Elekta, Stockholm, Sweden), and to check that all the necessary variables and parameters were synchronous.

Methods

Three tests (for gantry position–dose delivery synchronisation, gantry speed–dose delivery synchronisation and MLC leaf speed and positions) were performed.

Results

The average error in gantry position was 0.5° and the average difference was 3 MU for a linear and a parabolic relationship between gantry position and delivered dose. In the third part of this test (sawtooth variation), the maximum difference was 9.3 MU, with a gantry position difference of 1.2°. In the sweeping field method test, a linear relationship was observed between recorded doses and distance from the central axis, as expected. In the open field method, errors were encountered at the beginning and at the end of the delivery arc, termed the “beginning” and “end” errors. For MLC position verification, the maximum error was −2.46 mm and the mean error was 0.0153 ±0.4668 mm, and 3.4% of leaves analysed showed errors of >±1 mm.

Conclusion

This experiment demonstrates that the variables and parameters of the Synergy® S are synchronous and that the system is suitable for delivering VMAT using a dynamic MLC.The concept of volumetric modulated arc therapy (VMAT) has been described in many studies [1-5]. VMAT is a system for intensity-modulated radiotherapy treatment (IMRT) delivery that achieves high dose conformity by optimising the dose rate, gantry speed and leaf positions of the dynamic multileaf collimator (MLC) [6]. One study [5] demonstrated quality assurance (QA) checks using dynamic MLC controller log files (Dynalog) for VMAT systems such as RapidArc® (Varian Medical Systems Inc., Palo Alto, CA). It is assumed that the actual delivery process is truly represented in the log files [6]. The major disadvantage of this method is that Dynalog files need to be validated against an independent system. The electronic portal imaging device (EPID) is a dependable system when corrections are made for systematic tilts and shifts [7,8] and when image sagging due to gantry angle [9] has been taken into account. A significant number of researchers have investigated MLC QA by film or EPID [7-13] to measure the accuracy of the MLC controller independently and ensure that the MLC edge positions agree with the radiation field edges to within 0.3 mm [14]. EPID measurements are highly reproducible, with a standard deviation of <0.1 mm for individual leaf/collimator positions and <0.05 mm for a 10×10 cm² field [7]. Few studies [15-17] have demonstrated commissioning, QA and patient-specific QA for VMAT using both the RapidArc and the Synergy® S (Elekta, Stockholm, Sweden) systems. The purpose of this study was to demonstrate QA checks for accuracy of gantry speed and position, dose rate, MLC leaf speed and MLC position, and to ensure that all the necessary variables and parameters were synchronous. These simple tests were designed to fulfil the requirements and limits recommended by the American Association of Physicists in Medicine (AAPM) for the clinical implementation of IMRT [18] and a recent recommendation by AAPM task group 142 (TG-142) [19] for the QA of medical accelerators.     

Clinical utility of ¹⁸F FDG-PET/CT in the detection of bone marrow disease in Hodgkin's lymphoma

Objective

The aim of the study was to evaluate the potential role of fludeoxyglucose (FDG)-positron emission tomography (PET)/CT in the detection of bone/bone marrow disease in patients with Hodgkin''s lymphoma (HL).

Methods

We retrospectively reviewed (¹⁸F)-FDG-PET/CT scans of 122 newly diagnosed, biopsy-proven cases of HL performed between November 2009 and June 2010. All the patients were staged before treatment by both PET/CT and bone marrow biopsy (BMB). Patients were subdivided into three groups based on the findings of FDG-PET/CT. Group A consisted of patients showing diffuse FDG uptake, Group B consisted of patients showing unifocal FDG uptake and Group C patients showed multifocal FDG-avid foci on PET/CT scans. Bone marrow results were also reviewed and considered positive if lymphomatous involvement was detected on bone marrow trephine biopsy. BMB results were correlated with FDG-PET/CT findings.

Results

There were 122 patients in total—81 (66.4%) were male and 41 (33.6%) were female. The age range was from 6 years to 78 years (mean 35.70 years). PET/CT was reported as negative for bone/bone marrow involvement in 85 (69.7%) patients, while the remaining 37 showed abnormal FDG uptake. The sensitivity of FDG-PET/CT was calculated to be 100%, the specificity was 76.57%, the negative predictive value was 76.57%, the positive predictive value was 29.72% and the diagnostic accuracy was 78.62%.

Conclusion

¹⁸F-FDG-PET/CT and BMB are complementary in the evaluation of bone marrow disease.Fluorine-18 (¹⁸F)-fludeoxyglucose (FDG) has found widespread use in the diagnosis and staging work-up of lymphomas. One of the most promising applications is in the determination of clinical stage of disease at presentation or recurrence [1]. Accurate staging is essential for planning an effective treatment regimen and minimising side effects and toxicity [2]. Bone marrow infiltration is of prime importance not only in staging the disease but also in the tailoring of treatment protocols [3]. Bone involvement can result from haematogenous spread or by extension from adjacent soft tissues [4,5]. Bone marrow involvement in patients with lymphoma is considered as a sign of generalised disease and with less favourable prognosis. Bone marrow biopsy (BMB) is the established method for the detection of bone marrow infiltration. BMB is generally safe but should not be considered as a risk-free procedure; adverse events (haemorrhage, infection etc) have been reported in about 0.12% of cases [6]. It is an invasive and painful experience for the patients and it sometimes results in only a small sample which may turn out to be inconclusive. Bone marrow involvement is diagnosed in 50–80% of patients with low-grade non-Hodgkin''s lymphoma (NHL), 25–40% of those with high-grade NHL and 5–14% of those with Hodgkin''s lymphoma (HL) [6,7]. Lymphoma staging is based on Ann Arbor classification with Cotswolds modifications [8], which includes CT and BMB. Radiologically, CT may depict cortical bone changes but has low sensitivity for early bone marrow involvement [8,9]. Unilateral or bilateral BMB of the dorsal iliac crest is considered as the standard method for detecting bone marrow involvement complemented by MRI when needed [2,10-12]. The potential role of FDG-positron emission tomography (PET)/CT is yet to be determined for the assessment of bone marrow involvement, as very few systematic studies have been carried out in this regard. Since the advent of FDG-PET/CT, functional imaging has emerged as an important imaging tool in differentiating viable tumour tissue from necrotic and therapy-induced fibrosis [13,14]. The aim of the current study was to correlate BMB and PET/CT results as part of baseline staging work-up and to assess the clinical utility of FDG-PET/CT in the detection of bone/bone marrow disease.     

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.     

Characterisation of breast papillary neoplasm on automated breast ultrasound

Intraductal papillary neoplasms of the breast form a wide spectrum of pathological changes with benign intraductal papilloma and papillary carcinoma. They can occur anywhere within the breast ductal system. This review illustrates some characteristic appearances of breast papillary neoplasms on coronal planes reconstructed by automatic breast volume scan. Such manifestations are not uncommon in papillary neoplasms, and familiarity will enable confident diagnosis.Papillary lesions of the breast are a heterogeneous group of breast lesions, including intraductal papilloma, atypical papilloma and intraductal papillary carcinoma [1,2]. Although the management of intraductal papillomas is varied, surgical excision is generally recommended as a precaution against the risk of a subsequent carcinoma [3,4]. Recently, some studies have suggested that patients with a tumour measuring <1.5 cm and an ultrasound Breast Imaging—Reporting and Data System (BI-RADS) category of 3 or 4a can be potentially selected for vacuum-assisted biopsy, but only if the tumour does not extend into the branching ducts [5,6]. Ueng et al [2] recommended that localised papillary lesions should be excised completely with a small rim of uninvolved breast tissue without any prior needle instrumentation if and when the papillary nature can be determined by imaging. Therefore, a careful imaging evaluation is necessary because it could help to identify the papillary neoplasm nature and select the high-risk lesions for proper treatment.Ultrasound has a greater sensitivity for detecting all papillary lesions than mammography [7]. Recently, automated breast ultrasound scanners have been developed, and the ultrasound volume data set of the whole breast can be acquired in a standard manner [8]. They have already shown potential for characterisation of breast tumours [9,10]. However, these studies did not detail the ultrasound features of intraductal papillary neoplasms on automated breast ultrasound. The reconstructed coronal views are also expected to provide more information and thus help to differentiate these lesions from other focal breast abnormalities.