The intravertebral cleft in benign vertebral compression fracture: the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI

We compared the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI (CEMRI) in diagnosing intravertebral clefts in benign vertebral compression fractures (VCFs). We retrospectively reviewed 99 consecutive patients who had undergone percutaneous vertebroplasty for VCFs. A cleft was defined as a signal void or hyperintense area on non-enhanced MRI (T₁ and T₂ weighted imaging) or as a hypointense area within a diffusely enhanced vertebra on CEMRI. A cleft was confirmed as a solid opacification on post-procedural radiographs. The interobserver reliability and MRI diagnostic performance were evaluated. The interobserver reliability of non-enhanced MRI was substantial (k _ 0.698) and the interobserver reliability of CEMRI was almost perfect (k _ 0.836). Post-procedural radiographs showed solid cleft opacification in 32 out of the 99 cases. The sensitivity and specificity of non-enhanced MRI were 0.72 and 0.82 (observer 1) and 0.63 and 0.87 (observer 2), respectively. The sensitivity and specificity of CEMRI were 0.94 and 0.63 (observer 1) and 0.85 and 0.60 (observer 2), respectively. The sensitivity of CEMRI was significantly higher than that of non-enhanced MRI, and the specificity of non-enhanced MRI was higher than that of CEMRI. CEMRI was highly reliable and sensitive, and non-enhanced MRI was specific for intravertebral clefts. Therefore, spine MRIs, including CEMRI, could provide useful information about intravertebral clefts before percutaneous vertebroplasty.Intravertebral clefts associated with vertebral compression fractures (VCFs) are radiographic signs representing cavities within fractured vertebrae and have long been considered pathognomonic for avascular necrosis of the spine (Kümmell’s sign) [1–3]. However, several investigators have observed that intravertebral clefts are common in patients with osteoporotic compression fractures [4–6]. Currently, clefts are thought to represent corticocancellous disruption in mobile osteoporotic fractures, rather than avascular necrotic disease [4, 6].Percutaneous vertebroplasty (PV) is an effective and minimally invasive procedure for the treatment of osteoporotic compression fractures [7, 8]. The advent of PV as the major treatment option for VCFs has prompted interest in intravertebral clefts occurring in benign VCFs. Recent studies have suggested that the clinical outcomes and complications associated with PV are influenced by the presence of clefts [4, 9–13]. Thus, radiological detection of clefts is indispensable for managing patients with VCFs.Spine MRI is commonly used for the evaluation of acute VCFs. MRI is useful in distinguishing malignancy from acute osteoporotic VCFs [14, 15] and is effective in demonstrating bone marrow oedema associated with acute compression fractures, which is one of the indications for performing PV [14, 16]. The MRI findings associated with intravertebral clefts have been well described [3–5]. However, there is controversy concerning the efficacy of MRI in diagnosing clefts. Specifically, the reliability and effectiveness of contrast-enhanced MRI (CEMRI), first assessed by Oka et al in 2005 [11], has not been properly evaluated. Such evaluation is important, given that CEMRI entails additional expense.To evaluate the efficacy of the CEMRI for the prediction of intravertebral clefts, we assessed the interobserver reliability and diagnostic performance of non-enhanced T₁ weighted and T₂ weighted MRI (T1WI and T2WI) and CEMRI in the identification of intravertebral clefts in VCFs. We then compared the diagnostic performance of CEMRI with that of non-enhanced MRI.     

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.     

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     

Diffusion-weighted MRI in the follow-up of chronic periaortitis

Objective:

To evaluate the usefulness of diffusion-weighted MRI (DWI) for the assessment of the intraindividual follow-up in patients with chronic periaortitis (CP) under medication.

Methods:

MRI data of 21 consecutive patients with newly diagnosed untreated disease were retrospectively examined before and after medical therapy, with a median follow-up of 16 weeks. DWI parameters [b800 signal, apparent diffusion coefficient (ADC) values] of the CP and psoas muscle were analysed together with the extent and contrast enhancement. Pre- and post-treatment laboratory inflammation markers were acquired parallel to each MR examination.

Results:

Statistically significant lower b800 signal intensities (p ≤ 0.0001) and higher ADC values (p ≤ 0.0001) were observed after medical treatment within the fibrous periaortic tissue. Extent and contrast enhancement of the CP showed also a statistically significant decrease (p ≤ 0.0001) in the follow-up examinations, while the control parameters within the psoas muscle showed no differences.

Conclusion:

DWI seems to be a useful method for the evaluation of response to treatment without contrast agents. The technique may be helpful in the assessment of disease activity to guide further therapeutic strategies.

Advances in knowledge:

DWI detects significant differences in the intraindividual follow-up of CP under medical therapy.Chronic periaortitis (CP) is a proliferating fibroinflammatory disease of the perivascular retroperitoneal space and aortic wall.^1–4 Owing to adventitial inflammation, some recent theories consider CP as a large vessel vasculitis.⁵ Clinical manifestations of CP include idiopathic retroperitoneal fibrosis, inflammatory aortic aneurysm and perianeurysmal retroperitoneal fibrosis.^2,6,7 The three manifestations with very similar histopathological characteristics are distinguished by the diameter of the abdominal aorta and concomitant ureteral affection.^1,3,7Specific clinical symptoms are caused by extrinsic compression of the ureters or retroperitoneal veins, resulting in hydronephrosis, oliguria, lower extremity oedema and deep vein thrombosis.^1,8Under medical treatment with steroids, CP has a good prognosis.⁷ Today tamoxifen is suggested as a safe and effective therapeutic alternative, and immunosuppressive drugs can be considered in patients with suboptimal responses to these drugs or multiple relapses.^9–11CT and MRI are the modalities of first choice for diagnosis and follow-up of CP.^1,7,12 The fibrotic para-aortic tissue shows significant contrast uptake in gadolinium-enhanced MRI.^12–14 Dynamic contrast-enhanced MRI was suggested for the assessment of the disease activity.^15,16 However, in cases with impaired renal function (e.g. by ureteral compression), gadolinium-independent imaging methods should be preferred owing to the potential development of a nephrogenic systemic fibrosis.¹⁷Diffusion-weighted MRI (DWI) is a non-contrast MR modality that has been successfully applied for the assessment of retroperitoneal masses, inflammatory abdominal aortic aneurysms and for the differentiation between retroperitoneal fibrosis and malignant retroperitoneal neoplasms.^18–21DWI indicates restricted diffusion of water, for example caused by a high cellularity in malignant disease or active inflammation. The apparent diffusion coefficient (ADC) is a quantitative parameter for the level of restricted diffusion, which is calculated from the signals of different diffusion gradients (b-values).²²In the context of untreated CP diffusion-weighted MRI may detect restricted inflammation as a sign of high cellularity caused by active inflammation.There are no data for the evaluation of intraindividual follow-up and the response to treatment by DWI of CP so far. Therefore, the aim of the present study was to analyse differences in DWI signals during follow-up in patients with CP before and after treatment. In addition, we sought to elucidate the potential of DWI in the therapy monitoring of CP.     

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.     

Gd-EOB-DTPA-enhanced MRI for the assessment of liver function and volume in liver cirrhosis

Objective:

The aims of this study were to use dynamic hepatocyte-specific contrast-enhanced MRI to evaluate liver volume and function in liver cirrhosis, correlate the results with standard scoring models and explore the inhomogeneous distribution of liver function in cirrhotic livers.

Methods:

10 patients with liver cirrhosis and 20 healthy volunteers, serving as controls, were included. Hepatic extraction fraction (HEF), input relative blood flow and mean transit time were calculated on a voxel-by-voxel basis using deconvolutional analysis. Segmental and total liver volumes as well as segmental and total hepatic extraction capacity, expressed in HEFml, were calculated. An incongruence score (IS) was constructed to reflect the uneven distribution of liver function. The Mann–Whitney U-test was used for group comparison of the quantitative liver function parameters, liver volumes and ISs. Correlations between liver function parameters and clinical scores were assessed using Spearman rank correlation.

Results:

Patients had larger parenchymal liver volume, lower hepatocyte function and more inhomogeneous distribution of function compared with healthy controls.

Conclusion:

The study demonstrates the non-homogeneous nature of liver cirrhosis and underlines the necessity of a liver function test able to compensate for the heterogeneous distribution of liver function in patients with diseased liver parenchyma.

Advances in knowledge:

The study describes a new way to quantitatively assess the hepatic uptake of gadoxetate or gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid in the liver as a whole as well as on a segmental level.In patients undergoing liver resection, post-operative liver failure is a major concern and has in current practice become the biggest cause for mortality after liver resection [1–3]. Residual liver should be of adequate volume and quality to sustain immediate post-operative function and to allow regeneration for complete restoration of hepatic function. Currently, surgical decision-making is predominantly based on volume calculation from cross-sectional imaging, sometimes in combination with liver function evaluation [4,5]. A variety of different methods for quantitative assessment of global liver function are available, including clearance–retention tests, redox chemistry and scintigraphy [6,7]. All currently available metabolic tests give a global assessment of liver function and do not account or correct for the possible heterogeneous distribution of function within the liver parenchyma. Scoring models, of which the Child–Pugh score (CPS) [8,9] and the model for end-stage liver disease (MELD) [10] are the most frequently used, are hampered by the same limitations.A number of published studies, using different scintigraphic methods, have verified the presence of heterogeneous distribution of function in the liver parenchyma. In a group of patients with diverse underlying liver pathologies investigated with ^99mTc-mebrofenin, it was found that liver function was unevenly distributed within the liver [11]. Regional variations in uptake were also demonstrated using ^99mTc-labelled galactosyl human serum albumin [12,13]. This phenomenon was also observed in patients with primary sclerosing cholangitis using ^99mTc-HIDA [14].Gadoxetate or gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA; Primovist®, Bayer Healthcare, Berlin) is a contrast agent developed for MRI. It is a gadolinium chelate that is actively taken up into the hepatocytes through the organic anion-transporting polypeptides [15]. This is a property Gd-EOB-DTPA shares with the iminodiacetic acid compounds used in hepatobiliary scintigraphy (HBS) and with indocyanine green (ICG) [16–20]. Pharmacokinetic studies show that about 50% of the administered dose of Gd-EOB-DTPA is extracted by the liver and eliminated through the hepatobiliary pathway. The remaining 50% is eliminated by renal excretion [21]. As the hepatic elimination of Gd-EOB-DTPA is dependent on the integrity of the hepatocyte mass, quantification of the uptake should represent the same aspects of liver function as assessed by ICG clearance or HBS.Dynamic hepatocyte-specific contrast-enhanced MRI (DHCE-MRI) has previously been used in animal models for the evaluation of hepatic function in various experimental settings, either using semi-quantitative parameters or using deconvolutional analysis (DA) [22–25]. In human studies, liver parenchymal enhancement after administration of Gd-EOB-DTPA has been shown to correlate with ICG clearance and with liver cirrhosis as assessed by the CPS [26,27], and subsequent biliary excretion has been shown to be delayed in patients with impaired liver function [28]. In a study of patients with primary biliary cirrhosis, quantitative parameters indicative of liver function derived from DA were shown to correlate with disease severity [29]. Also, compartmental modelling has been used to assess the hepatic uptake of Gd-EOB-DTPA, and the parameters derived were shown to be dependent on the CPS [30]. These findings support the hypothesis that results from DHCE-MRI have the potential to assess liver function.The present study should be regarded as a feasibility study aiming to investigate DHCE-MRI as a method to explore the inhomogeneous distribution of liver function in patients with liver cirrhosis compared with a control group and to explore the correlation between DHCE-MRI-derived liver function parameters with commonly used clinical scoring models. The primary outcome was the overall hepatic extraction capacity of Gd-EOB-DTPA, and secondary outcomes were measures of liver function heterogeneity, liver function indices and correlation analysis.     

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.     

Focal nodular hyperplasia: characterisation at gadoxetic acid-enhanced MRI and diffusion-weighted MRI

Purpose:

The aim of this study was to assess the enhancement patterns of hepatic focal nodular hyperplasia (FNH) on gadoxetic acid-enhanced MRI and diffusion-weighted (DW) MRI.

Methods:

This retrospective study had institutional review board approval. Gadoxetic acid-enhanced and DW MR images were evaluated in 23 patients with 30 FNHs (26 histologically proven and 4 radiologically diagnosed). The lesion enhancement patterns of the hepatobiliary phase images were classified as heterogeneous or homogeneous signal intensity (SI), and as dominantly high/iso or low SI compared with those of adjacent liver parenchyma. Heterogeneous (any) SI lesions and homogeneous low SI lesions were categorised into the fibrosis group, whereas homogeneous high/iso SI lesions were categorised into the non-fibrosis group. Additionally, lesion SI on T₂ weighted images, DW images and apparent diffusion coefficient (ADC) values were compared between the two groups.

Results:

The lesions showed heterogeneous high/iso SI (n=16), heterogeneous low SI (n=5), homogeneous high/iso SI (n=7) or homogeneous low SI (n=2) at the hepatobiliary phase MR images. The fibrosis group lesions were more likely to show high SI on DW images and T₂ weighted images compared with those in the non-fibrosis group (p<0.05). ADC values tended to be lower in the fibrosis group than those in the non-fibrosis group without significance.

Conclusion:

FNH showed variable enhancement patterns on hepatobiliary phase images during gadoxetic acid-enhanced MRI. SI on DW and T₂ weighted images differed according to the fibrosis component contained in the lesion.

Advances in knowledge:

FNH shows a wide spectrum of imaging findings on gadoxetic acid-enhanced MRI and DW MRI.Focal nodular hyperplasia (FNH) is the second most common benign hepatic tumour after haemangioma, and most frequently occurs in females of childbearing and middle age [1]. It is considered to result from a congenital vascular disorder leading to a hyperplastic response of the surrounding liver parenchyma and is histologically characterised by normal hepatocytes with malformed bile ducts [2,3]. It is generally accepted that FNH can be managed conservatively and most cases do not require surgery because of the lack of malignancy potential and low risk of complications such as rupture or haemorrhage [4,5]. Therefore, the goal of imaging is to make a confident diagnosis and to avoid a biopsy or even surgical resection.MRI is a well-established and widely used diagnostic modality for detecting and characterising focal hepatic lesions and generally allows a confident diagnosis of typical FNH [6–8]. Findings of typical FNH on conventional gadolinium-enhanced MRI are brisk arterial enhancement, iso or slightly low signal intensity (SI) on the portal and equilibrium phase, iso or slightly low SI on T₁ weighted images, iso or slightly high SI on T₂ weighted images, a central scar showing high SI on T₂ weighted images and delayed dynamic enhancement [6–9]. However, when atypical imaging features are present, such as atypical findings of a central scar, high SI on T₁ weighted images or washout during the portal or equilibrium phase, it is not easy to distinguish FNH from other hypervascular tumours, such as hepatocellular adenomas, hypervascular metastasis or fibrolamellar hepatocellular carcinomas [6,9]. Indeed, according to a study by Bieze et al [6], characterisation of FNH and hepatocellular adenoma on standard MRI is inconclusive in 40% of lesions.Gadoxetic acid (Primovist®; Bayer-Schering Pharma, Berlin, Germany) is a new recently approved hepatobiliary gadolinium-based contrast agent. It has dual pharmacokinetic actions that combine extracellular properties for dynamic phase imaging with high hepatocyte-specific uptake and biliary excretion for delayed hepatobiliary phase imaging [10,11]. Many reports have concluded that FNHs show liver-specific enhancement and appear as iso or high SI on hepatobiliary phase imaging, and this enhancement pattern is a new additional criterion for diagnosing FNH, particularly in comparison with hepatocellular adenoma [6,10–15]. However, even though the major enhancement features of FNH are iso or high SI on hepatobiliary phase imaging, the portion of the central stellate scar or radiating fibrous septa of FNH demonstrates low SI owing to a lack of functioning hepatocytes. We postulate that the overall SI of FNH lesions during hepatobiliary phase imaging is dependent on their proportions of cellular and fibrous components.Diffusion-weighted (DW) imaging is useful for the detection and characterisation of hepatic focal lesions [16–18]. In theory, DW imaging measures the random motion of water molecules in biological tissues and reflects tissue properties, such as the size of the extracellular space, viscosity and cellularity [18–20]. According to prior hepatic fibrosis evaluations using DW imaging, lower apparent diffusion coefficient (ADC) values are observed in cirrhotic liver compared with normal liver tissue, which may be owing to restricted diffusion from extracellular fibrosis [21–25]. Despite the fact that FNH is benign, some lesions show diffusion restrictions, probably owing to their high cellularity [26–28], and fibrosis components contained in FNH lesions should influence the degree of diffusion restriction.The purpose of this study was to classify FNH lesions according to their enhancement pattern on hepatobiliary phase imaging and to assess the findings on DW and T₂ weighted imaging of the lesions with regard to those on hepatobiliary phase imaging.     

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.     

Combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI improves the detection of colorectal liver metastases

Objectives

To compare the diagnostic accuracy of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, diffusion-weighted MRI (DW-MRI) and a combination of both techniques for the detection of colorectal hepatic metastases.

Methods

72 patients with suspected colorectal liver metastases underwent Gd-EOB-DTPA MRI and DW-MRI. Images were retrospectively reviewed with unenhanced T₁ and T₂ weighted images as Gd-EOB-DTPA image set, DW-MRI image set and combined image set by two independent radiologists. Each lesion detected was scored for size, location and likelihood of metastasis, and compared with surgery and follow-up imaging. Diagnostic accuracy was compared using receiver operating characteristics and interobserver agreement by kappa statistics.

Results

417 lesions (310 metastases, 107 benign) were found in 72 patients. For both readers, diagnostic accuracy using the combined image set was higher [area under the curve (Az) = 0.96, 0.97] than Gd-EOB-DTPA image set (Az = 0.86, 0.89) or DW-MRI image set (Az = 0.93, 0.92). Using combined image set improved identification of liver metastases compared with Gd-EOB-DTPA image set (p<0.001) or DW-MRI image set (p<0.001). There was very good interobserver agreement for lesion classification (κ = 0.81–0.88).

Conclusions

Combining DW-MRI with Gd-EOB-DTPA-enhanced T₁ weighted MRI significantly improved the detection of colorectal liver metastases.In patients with colorectal cancer, accurate assessment of the size, location and segmental distribution of liver metastases on a per-lesion basis is critical for treatment planning [1]. Accurate depiction of the size and distribution of liver metastases helps the selection of patients to undergo radical surgery [2,3] or minimally invasive therapy, such as radiofrequency ablation (RFA) [4], chemo-embolisation or radio-embolisation [5].The image contrast in diffusion-weighted MRI (DW-MRI) is based on differences in the mobility of water between tissues [6]. In tumour tissues, such as liver metastases, water mobility is often more impeded compared with normal parenchyma. Hence, metastases appear to have high signal intensity on DW-MRI, facilitating their detection.Compared with conventional T₂ weighted imaging, DW-MRI has been found to be superior for lesion detection in the liver [7-9]. When compared with contrast-enhanced MRI, DW-MRI had a higher diagnostic accuracy compared with superparamagnetic iron oxide (SPIO)-enhanced MRI [10] and similar diagnostic accuracy compared with gadolinium contrast-enhanced imaging [11] for detecting colorectal liver metastases. DW-MRI has also been found to be more sensitive than fluorodeoxyglucose (¹⁸FDG) positron emission tomography (PET) CT [12] for the same clinical indication. In another study, combining DW-MRI with T₁ weighted imaging after liver-specific contrast medium mangafodipir trisodium (MnDPDP) administration improved the diagnostic accuracy of colorectal liver metastases detection compared with either technique alone [13].Gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA; Eovist or Primovist; Bayer Schering Pharma, Berlin, Germany) is a relatively new hepatocyte-selective MR contrast medium that has been shown to be useful detecting liver metastases measuring <1 cm in diameter [14,15]. Delayed T₁ weighted imaging in the hepatocellular phase of contrast enhancement at 20 min to several hours after contrast administration demonstrates metastases as T₁ hypointense lesions against the avidly enhancing liver parenchyma.Both DW-MRI and Gd-EOB-DTPA-enhanced MRI are useful for the detection of liver metastases [7,8,14-16]. One study performed at 3 T compared the diagnostic performance of the two techniques for the identification of small (<2 cm) liver metastases [17]. Another study at 1.5 T independently compared the diagnostic performance of DW-MRI, dynamic phase MRI and hepatobiliary phase Gd-EOB-DTPA-enhanced MRI [18]. However, the possible incremental value of combining DW-MRI with Gd-EOB-DTPA-enhanced MRI for detecting colorectal metastases has not been reported. Hence, the aim of this study was to compare the diagnostic accuracy of Gd-EOB-DTPA-enhanced MRI, DW-MRI and a combination of both techniques for the detection of colorectal hepatic metastases.     

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].     

Simplified rules for everyday delineation of lymph node areas for breast cancer radiotherapy

The aim of this study was to present the simplified rules of delineation of lymph node (LN) volumes in breast irradiation. Practical rules of delineation of LN areas were developed in the Department of Radiation Oncology of the Institut Curie. These practical guidelines of delineation were based on different specific publications in the field of breast and LN anatomy. The principal characteristic of these rules is their clearly established relationship with anatomical structure, which is easy to find on CT slices. The simplified rules of delineation have been published in pocket format as the illustrated atlas “Help of delineation for breast cancer treatment”. In this small pocket guide, delineation using the practical rules is illustrated, with examples from anatomical CT slices. It is shown that there is an improvement in delineation after the use of these simplified rules and the guide. In conclusion, this small guide is useful for improving everyday practice and decreasing the differences in target delineation for breast irradiation between institutions and observers.The value of lymph node irradiation has already been demonstrated by various studies and meta-analyses [1–3]. In the age of new conformal techniques, there is a real need for a clear definition of treated volumes, such as breast, tumour bed, lymph node areas and organs at risk (OAR) [4–10]. Many teams have been working for several years on the definition of treated volumes. Some delineation studies are exclusively theoretical and some provide a good anatomical atlas, but this information is difficult to use in everyday practice [4–15]. The treatment position has also been shown to be an important factor of variability in the depth and situation of lymph node volumes [5, 6]. Conformal and intensity-modulated radiotherapy (IMRT) require an exact definition of target volumes in terms of their anatomical limits for delineation on CT scans. Some authors have proposed anatomically based landmarks specific for breast cancer radiotherapy in order to delineate all regional lymph nodes and the breast [5, 6, 8, 10, 15, 16]. Despite this work, two recent papers have demonstrated the individual interobserver variability and differences in target and OAR delineation for breast irradiation, especially in lymph node areas [7, 8].This study was designed to propose a practical method to improve and facilitate the everyday delineation process for the clinicians of our department.     

Comparison of mammography, sonography, MRI and clinical examination in patients with locally advanced or inflammatory breast cancer who underwent neoadjuvant chemotherapy

Objectives

The purpose of this study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced or inflammatory breast cancer. Each prediction method was compared with the gold standard of surgical pathology.

Methods

43 patients (age range, 25–62 years; mean age, 42.7 years) with locally advanced or inflammatory breast cancer who had been treated by neoadjuvant chemotherapy were enrolled prospectively. We compared the predicted residual tumour size and the predicted response on imaging and clinical examination with residual tumour size and response on pathology. Statistical analysis was performed using weighted kappa statistics and intraclass correlation coefficients (ICC).

Results

The ICC values between predicted tumour size and pathologically determined tumour size were 0.65 for clinical examination, 0.69 for mammography, 0.78 for sonography and 0.97 for MRI. Agreement between the response predictions at mid-treatment and the responses measured by pathology had kappa values of 0.28 for clinical examination, 0.32 for mammography, 0.46 for sonography and 0.68 for MRI. Agreement between the final response predictions and the responses measured by pathology had kappa values of 0.43 for clinical examination, 0.44 for mammography, 0.50 for sonography and 0.82 for MRI.

Conclusion

Predictions of response and residual tumour size made on MRI were better correlated with the assessments of response and residual tumour size made upon pathology than were predictions made on the basis of clinical examination, mammography or sonography. Thus, the evaluation of predicted response using MRI could provide a relatively sensitive early assessment of chemotherapy efficacy.The advantages of neoadjuvant chemotherapy are multiple and it has been used widely during the past few years [1]. Its primary role is to induce tumour shrinkage and permit breast-conserving surgery, primarily in patients with advanced breast cancer [2-4]. Neoadjuvant chemotherapy allows earlier treatment of micrometastatic disease and the study of biological markers that might predict tumour response [5]. The effectiveness of chemotherapeutic agents in treating both primary breast cancer and potential metastatic disease may be enhanced by the presence of tumour neovascularity. If chemotherapy is given before surgery, while tumour vascularity remains intact, the chemotherapeutic agents may be better able to reach the tumour and thus be more effective.Neoadjuvant chemotherapy of locally advanced breast cancer (LABC) has also been shown to improve the resectability rate, offering disease-free and overall survival rates that are at least equivalent to those offered by surgery alone [6,7]. Pathological complete response (pCR) is clinically significant because it is associated with improved long-term prognosis and decreased risk of recurrence [6,8]. Decisions regarding the continuation of current regimens and the appropriate type and timing of surgery depend on the radiological and clinical assessment of residual tumour size during neoadjuvant chemotherapy [9,10]. Until now, many studies have shown that physical examinations, mammography and sonography provide suboptimal evaluations of lesion extent that do not allow accurate assessments of pathological response or residual tumour size [5^,11-13]. In the case of LABC, physical examination, mammography or sonography may be suitable for detecting the larger lesions of non-responders, but they have limited sensitivity for responders with smaller residual lesions [14,15]. For mammography, calcifications may persist or even increase in patients who respond to neoadjuvant chemotherapy [14,16,17].Many previous studies have shown that MRI is the most reliable technique for evaluating residual disease after neoadjuvant chemotherapy, although initial reports described frequent false-negatives with smaller-volume disease [18-27]. Recent studies have increased the sensitivity of MRI, with increased resolution, reduced slice thickness and lower enhancement thresholds being used to minimise the underestimation of residual disease [15^,22-27]. It is still difficult, however, to distinguish residual scarring, necrosis and fibrosis from viable residual malignancy and to predict accurate response after neoadjuvant chemotherapy, especially in responders. Few published studies have described work with patients with inflammatory breast cancer who underwent neoadjuvant chemotherapy because the incidence of this disease is very low [28,29]. The purpose of our study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced and inflammatory breast cancer. We compared each prediction method with the gold standard of surgical pathology.     

Embolisation of the right gastric artery in patients undergoing hepatic arterial infusion chemotherapy using two possible approach routes

We used a retrospective non-randomised study to investigate the clinical effect of selective embolisation of the right gastric artery before hepatic arterial infusion chemotherapy (HAIC) using a port-catheter system. We evaluated whether the hepatic artery or the left gastric artery is the better approach for selecting the right gastric artery. A total of 367 patients (244 men and 123 women; mean age, 64.1 years) with unresectable advanced liver cancer underwent percutaneous implantation of a port-catheter system. In 294 of these patients, right gastric arterial embolisation with microcoils was attempted before placement of the port-catheter system to prevent gastric mucosal lesions. Approach was either through the hepatic artery (175 patients) or through the left gastric artery (119 patients), with success rates in catheterising the right gastric artery of 78.3% and 77.3%, respectively. If the attempt was unsuccessful, the catheter was redirected to the alternative approach, which increased the final success rate to 96.3%. Only seven patients experienced gastroduodenal mucosal lesions acutely after HAIC, as revealed by endoscopy. Embolisation of the right gastric artery is a feasible procedure that can reduce the incidence of gastric mucosal lesions associated with HAIC. Approach through either the hepatic artery or the left gastric artery is equally acceptable.Long-term hepatic arterial infusion chemotherapy (HAIC) via an implanted port-catheter system is a treatment option for patients with unresectable advanced liver cancer [1, 2]. In the past, such catheter placement was done by surgical laparotomy under general anaesthesia [3–6], an invasive procedure. However, recent advances in interventional techniques allow the implantation of port-catheter systems percutaneously under local anaesthesia [7–14].A frequent complication is reactive gastric or duodenal mucosal lesions, which result from chemical irritation caused by infusion of chemotherapeutic agents into adjacent organs through arteries originating from the common hepatic artery [15–24]. One such complication is a gastric mucosal lesion caused by inflow of chemotherapeutic agents into the right gastric artery [15–24]. To prevent this complication, the efficacy of selectively embolising the right gastric artery with coils at the time of implantation of the port-catheter system has been noted [21, 25–27].In many cases, however, the right gastric artery is slender and angulated, with anatomical variations [26, 28–31]. Hence, it is occasionally difficult to insert a catheter selectively into the right gastric artery by antegrade catheterisation via the site of the hepatic artery. This is the approach most commonly used by interventional radiologists. Failure to embolise the right gastric artery can result [26]. As an alternative method, a retrograde approach to the right gastric artery via the left gastric artery has been introduced [32, 33].Because HAIC with an implanted port-catheter system is performed in a relatively large number of cases in our institution, we have many opportunities to embolise the right gastric artery using both approaches. The aim of the present retrospective non-randomised study, which included a large number of subjects, was to evaluate the usefulness of right gastric arterial embolisation and to determine whether the antegrade or retrograde approach is more useful.     

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.     

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.     

3T diffusion-weighted MRI of the thyroid gland with reduced distortion: preliminary results

Objective:

Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging the thyroid, is characterised by severe blurring and distortion. The objectives of this work were: 1, to show that a reduced-field of view (r-FOV) DW EPI technique can improve image quality; and 2, to investigate the effect of different reconstruction strategies on the resulting apparent diffusion coefficients (ADCs).

Methods:

We implemented a single-shot, r-FOV DW EPI technique with a two-dimensional radiofrequency excitation pulse for DW imaging of the thyroid at 3T. Images were reconstructed using root sum of squares (SOS) and an optimal-B₁ reconstruction (OBR). Phantom and in vivo experiments were performed to compare r-FOV and conventional full-FOV DW EPI with root SOS and OBR.

Results:

r-FOV with OBR substantially improved image quality at 3T. In phantoms, r-FOV gave more accurate ADCs than full-FOV. In vivo r-FOV always gave lower ADC values with respect to the full-FOV technique irrespective of the reconstruction used and whether only two or multiple b-values were used to compute the ADCs.

Conclusion:

r-FOV DW EPI can reduce image blurring and distortion at the expense of a low signal-to-noise ratio. OBR is a promising reconstruction technique for accurate ADC measurements in lower signal-to-noise ratio regimes, although further studies are needed to characterise its performance.

Advances in knowledge:

DW imaging of the thyroid at 3T could potentially benefit from r-FOV acquisition strategies, such as the r-FOV DW EPI technique proposed in this paper.Diffusion-weighted (DW) imaging has been shown to provide useful information to differentiate between benign and malignant thyroid nodules [1–4]. Single-shot echo-planar imaging (EPI) is the most frequently used technique because of its relative immunity to motion-induced phase errors, high signal-to-noise ratio (SNR) and short acquisition times [5,6]. However, single-shot DW EPI images are characterised by blurring along the phase-encode direction due to T₂^* decay and are sensitive to off-resonance effects (B₀ inhomogeneities, susceptibility gradients, eddy currents, chemical shift) because of the narrow bandwidth in the phase-encode direction.The use of parallel imaging has been shown to provide considerable improvement in terms of image quality [7,8]. However, residual aliasing artefacts and noise amplification are often observed with clinically available phased-array coils combined with reduction factors >2, which limits the applicability of this technique. Another strategy to reduce the number of acquired k-space lines and, hence, off-resonance-induced phase errors and blurring, is to restrict the excitation phase field of view (FOV) to the anatomy of interest, so that the EPI echo-train length can be reduced without fold-over artefacts. This technique has been shown to be particularly effective for imaging the spine [9–12] and has also been reported in the carotid artery [13], the optic nerve [14] and the prostate [15]. Unlike parallel imaging, the phase FOV can be arbitrarily reduced to frame the anatomy of interest with an SNR penalty which is generally lower than that associated with parallel imaging combined with the same reduction factor. However, depending on the approach adopted in excitation to limit the FOV, contiguous multi-slice imaging may not be possible [11], or may require additional pulses for outer-volume suppression [12], or may be characterised by a variable SNR as a function of the number of slices [9]. Saritas et al used a two-dimensional (2D) spatially selective radiofrequency (RF) pulse in combination with a 180° refocusing pulse to limit the excitation FOV in the phase-encode direction and allow contiguous multi-slice imaging [10,16,17]. The same pulse sequence also provided fat suppression without the need for additional pulses by chemically shifting the fat profile outside of the imaging volume refocused by the 180° pulse.A well-known drawback of quantitative DW imaging in inherently low-SNR situations, as in the case of reduced-FOV (r-FOV) techniques, is the systematic underestimation of apparent diffusion coefficients (ADCs), which can result from rectified noise being included into the fitting procedure if magnitude averaging is used [18]. In the original work from Saritas et al, complex averaging was used after correcting the raw data for eventual shot-to-shot motion-induced phase errors at the expense of an increased complexity of the reconstruction [10,19]. Optimal-B₁ image reconstruction (OBR) using array coils [20], i.e. conventional non-accelerated parallel-imaging reconstruction, has been shown to improve the accuracy of T₂ and T₂^* quantification in low-SNR cases [21], suggesting a potentially useful application of this technique to reconstruct inherently low-SNR r-FOV images for subsequent ADC mapping.In this work, we used a 2D spatially selective RF pulse similar to the one designed by Saritas et al [10,16,17] to perform contiguous, multi-slice, fat-suppressed, r-FOV, single-shot DW EPI of the thyroid gland at 3T [22], together with an eddy-current-compensated diffusion-encoding scheme [23] and B1-optimal reconstruction, to reduce the noise floor resulting from magnitude averaging [20]. Phantom experiments were performed to validate the ADC measurements, and in vivo applications in healthy volunteers were evaluated and compared with the standard full-FOV single-shot DW EPI pulse sequence.     

Contrast-enhanced MRI of the subdeltoid,subacromial bursa in painful and painless rotator cuff tears

Objective

Although shoulder pain is often associated with rotator cuff tears, many tears are asymptomatic and are not the cause of the patient''s pain. This may explain the persistence of symptoms in some patients despite technically successful rotator cuff repair. It has been proposed that rotator cuff tears cause pain through subdeltoid/subacromial bursal inflammation. The aim of this study was to determine whether bursal inflammation seen on MRI is associated with pain in patients with rotator cuff tears of the shoulder.

Methods

The shoulders of 255 patients were screened with ultrasound. 33 full-thickness rotator cuff tears (18 with shoulder pain and 15 without pain) were identified and subsequently studied using contrast-enhanced MRI of the shoulder. Enhancement of the subacromial bursa was scored independently by two musculoskeletal radiologists. Logistic regression was used to determine whether bursal enhancement was independently associated with pain.

Results

There was a significant association between pain and age, with greater likelihood of pain in younger patients. Bursal enhancement was common in both painful and painless tears. No statistically significant link between pain and bursal enhancement was seen, even after accounting for age.

Conclusion

Although enhancement of the subdeltoid/subacromial bursa was common, no evidence was found to support the hypothesis that bursal enhancement is associated with pain in rotator cuff tears. It is therefore unlikely to determine reliably which patients would benefit from rotator cuff repair.

Advances in knowledge

Bursal enhancement and thickening does not reliably correlate with symptoms or presence of rotator cuff tear.Rotator cuff tears are a common cause of pain in the shoulder. Surgical repair is an effective treatment, but a significant proportion of patients (5–12.5%) fail to achieve a satisfactory outcome [1-4]. Long-term outcome of surgery correlates poorly with the integrity of the cuff repair [5-7] and persistence of pain is a major factor [1]. In some cases, this may be because the shoulder pain is not due to rotator cuff damage at all [8]. Other painful shoulder pathologies are common, particularly in the elderly, including glenohumeral and acromioclavicular arthritis [9], and bone marrow oedema [10]. Asymptomatic rotator cuff tears are common, with increasing incidence with age and a reported prevalence of up to 80% in subjects aged over 80 years [11]. A significant proportion of these are full-thickness tears with one study reporting full-thickness tears in 28% of people over the age of 60 [12]. Rotator cuff tears may remain asymptomatic despite their large size [13] and, although the size of tears often increases, symptoms may develop or resolve with conservative treatment [14-16]. As yet there is no clear consensus regarding the indications for rotator cuff surgery [17,18]. A technique to determine whether a known rotator cuff tear is responsible for an individual patient''s pain would therefore be of great clinical value in developing patient management plans. While MRI has been shown to be accurate for detecting rotator cuff tears [19,20], there is no convincing evidence to date that it can be used to determine whether a full-thickness tear is symptomatic [12,21].The mechanism by which rotator cuff tears cause pain is poorly understood. Tears are associated with histological inflammation of the subdeltoid/subacromial bursa and this has recently been proposed as a cause of pain [22]. Synovial inflammation in the bursa in symptomatic rotator cuff tears could potentially be detected by the associated enhancement in the inflamed bursa seen on MRI after the administration of intravenous contrast agent, in the same way that synovial volume in joints in inflammatory arthritis has been shown to correlate with histological measures of inflammation [23]. The aim of this study was to use contrast-enhanced MRI to assess subacromial bursitis in patients with painful and painless rotator cuff tears in order to test the hypothesis that synovial enhancement at the subacromial bursa is greater in patients with shoulder pain.