Magnetic Resonance Elastography and Diffusion Weighted Imaging in the Evaluation of Hepatic Fibrosis in Chronic Hepatitis B

BACKGROUND/AIMS: Comparison of the accuracy of magnetic resonance elastography (MRE) and diffusion weighted imaging (DWI) for the diagnosis of liver fibrosis in patients with chronic hepatitis B (CHB). METHODS: In this retrospective analysis, we investigated 63 patients with CHB and liver fibrosis. DWI was performed with both breath-hold (DWI-BH) and free-breathing (DWI-FB) sequences (b=0, 500). The mean liver stiffness and apparent diffusion coefficient (ADC) were calculated by drawing regions of interest maps. Fibrosis staging according to the METAVIR system was independently performed by an experienced pathologist. A receiver operating curve (ROC) analysis was conducted to determine the accuracy of MRE, DWI-BH and DWI-FB in the detection and stratification of liver fibrosis. The performance of the detection of significant fibrosis (≥F2), advanced fibrosis (≥F3), and cirrhosis (F4) was also evaluated by comparing areas under the ROC. RESULTS: There was a moderate and significantly negative correlation between the ADC values and liver stiffness. The accuracies for the detection of ≥F2/≥F3/F4 stage fibrosis with DWI-FB, DWI-BH and MRE were 0.84/0.76/0.72, 0.72/0.83/0.79 and 0.99/0.99/0.98, respectively. The performance of MRE was significantly better than DWI-FB and DWI-BH. There were no significant differences between the performance of DWI-FB and DWI-BH. CONCLUSIONS: MRE is more accurate than DWI for the detection and stratification of liver fibrosis in CHB.

Melioidosis: spectrum of radiological manifestations

Melioidosis, a bacterial infection caused by Burkholderia pseudomallei is expanding in its endemicity around the world. Melioidosis most commonly infects adults with an underlying predisposing condition, mainly diabetes mellitus. Primary skin and soft tissue involvement is more common in younger patients. Almost every organ can be affected, but the most commonly affected organ is the lung followed by the spleen. Melioidosis has a wide range of radiological manifestations making it a mimicker. Diagnosis requires a high index of clinical suspicion in patients with septicemia or a fever of unknown origin living in or with a travel history to endemic areas. We present a pictorial review of the radiological manifestations of melioidosis, which is a useful knowledge for radiologists to help arrive at an early diagnosis. In this pictorial review, we present the radiological manifestations chosen from 139 patients with culture proven melioidosis. Illustrated examples are chosen from our clinical experience of the past 15 years at the National University Hospital in Singapore

CT-guided thoracic biopsy: evaluating diagnostic yield and complications

<p><b>INTRODUCTION</b>This study retrospectively evaluated CT-guided thoracic biopsies for diagnostic yield, accuracy and complications.</p><p><b>MATERIALS AND METHODS</b>A retrospective analysis of 384 patients (mean age 62.7 years; male/female = 251/133) who underwent 399 CT-guided thoracic biopsies were performed for evaluating diagnostic yield, accuracy and complications. Correlations between patients age, procedure factors (biopsy-needle size, number of passes, lesion-size, lesion-depth and traversed lung-length) and complications such as pneumothorax, haemothorax and haemoptysis were evaluated. A comparison between fine needle aspiration (FNA) group and core ± FNA group for diagnostic yield and complications was also performed.</p><p><b>RESULTS</b>FNA was performed in 349 patients and core ± FNA in 50 patients. The biopsy samples were adequate in 91.9% and the diagnostic accuracy for malignant lesions was 96.8% with 95.7% sensitivity and 100% specificity. Pneumothorax (detected on CT) occurred in 139 cases (34.8%) and only 12 (3.0%) required insertion of an intercostals drain. Mild haemoptysis occurred in 13 patients (3.2%) and small haemothoraces in 2 patients. Pneumothorax occurrence was significantly associated with the traversed lung-length (>3mm), lesion-size (≤33 mm) and lesion-depth (≥60mm) (P <0.05). Haemoptysis occurrence was also significantly associated with traversed lunglength (>3mm) and lesion-size (≤33 mm) (P <0.05). There was no significant difference between diagnostic yield and complication rate between FNA and core ± FNA groups.</p><p><b>CONCLUSION</b>CT-guided thoracic biopsy is a safe procedure with high diagnostic yield and low risk of significant complications. Traversed lung-length and smaller lesion size are associated with occurrence of pneumothorax and haemoptysis.</p>

Computed tomography features in enteric fever

<p><b>INTRODUCTION</b>Enteric fever is a common infection in endemic areas; however, there are few reports describing the computed tomography (CT) manifestations of enteric fever. We aim to describe and illustrate CT findings in enteric fever in this study.</p><p><b>MATERIALS AND METHODS</b>A retrospective search of medical records in our institute for patients with positive blood cultures for Salmonella typhi, and Salmonella paratyphi organisms yielded 39 cases. Among these patients, 12 had undergone a CT study of the abdomen. The CT images, laboratory and clinical findings of these 12 patients were reviewed.</p><p><b>RESULTS</b>The most common clinical presentation was fever (100%). Typical features of gastroenteritis were present in only over half of the patients. Liver function tests were abnormal in all patients. The most common abdominal manifestations on CT were the presence of mesenteric lymphadenopathy and splenomegaly (75%). Other features were circumferential small bowel wall thickening (58.3%) and free intraperitoneal fluid (50%). Three patients were found to have complications; one with bleeding from terminal ileal ulceration, another with an ileal perforation and the third with renal abscess formation.</p><p><b>CONCLUSION</b>CT is useful in evaluating enteric fever in patients with severe forms of presentation, a longer clinical course or less specific symptoms. Although the imaging features overlap with other abdominal infections, when combined with clinical features, travel history to endemic areas and presence of transaminitis, the diagnosis of enteric fever should be considered. CT in particular, is useful for the detection of complications such as perforation, bleeding and abscess formation.</p>

A survey of local preclinical and clinical medical students' attitudes towards radiology

<p><b>INTRODUCTION</b>This study compares the attitudes between preclinical and clinical medical students towards radiology, following the introduction of a new radiology curriculum for 1st year students.</p><p><b>MATERIALS AND METHODS</b>Revision of the 1st year medical school curriculum for the academic year of 2008/9 with the inclusion of 13 one-hour formal radiology lectures integrated with each body system was done in an undergraduate Southeast Asian medical school. In the old curriculum, 1st and 2nd year medical students are not exposed to radiology. They received limited radiology teaching in their 3rd and 5th years with 2 one-hour lectures as part of their medicine and surgery rotations. In the 4th year, they have a one week non-examinable posting in radiology. A survey was administered to preclinical (new curriculum) and clinical (old curriculum) students. Survey responses were tabulated and attitudes between preclinical and clinical students were compared.</p><p><b>RESULTS</b>More than half of the preclinical students (155 out of 270 students, 59%) and 90 out of 720 clinical students (12.5%) responded. Students exposed to the new curriculum had attended one or two dedicated radiology lectures and were considering radiology as a clinical elective. Both groups of students did not feel familiar with radiology as with other specialties, were not considering radiology as a career, but felt that radiology was interesting and important to the overall practice of medicine.</p><p><b>CONCLUSIONS</b>Exposure of 1st year students to radiology increases their interest in the subject. Further intervention, fi ne-tuning of the curriculum and follow-up surveys will be carried out to see if this interest persists throughout their clinical years.</p>