CT appearance of the normal appendix in adults

The aims of this study were to identify (1) the normal range of the appendix on computed tomography (CT), (2) the correlation of patient age and sex with the visibility and appearance of the appendix on CT, and (3) the normal variations in wall thickness, intraluminal content, and location of the appendix. Three hundred seventy-two outpatients underwent abdominopelvic CT. The scans were reviewed on the picture archiving and communication system and appendiceal outer-to-outer wall diameter, wall thickness, location, content and its correlation with appendix diameter were analyzed. The appendix was visualized in 305/372 patients. Its location relative to the cecum was highly variable. The diameter range was 3-10 mm; in 42% of cases the diameter was greater than 6 mm. When the intraluminal content (185/305) was visualized, the diameter was slightly superior to the mean (p=0.0156). In 329 CT scans in which oral contrast material was given, the appendix was filled by contrast material in 74/329 patients. The appendix wall thickness was measurable in 22/305 patients (average 0.15 cm). There is significant overlap between the normal and abnormal CT appearance of the appendix. Consequently the diagnosis of acute appendicitis should be based not only on the appearance of the appendix but also on the presence of secondary sign

Diagnostic per-lesion performance of a simulated gadoxetate disodium-enhanced abbreviated MRI protocol for hepatocellular carcinoma screening.

AimTo evaluate the diagnostic per-lesion performance of a simulated gadoxetate disodium-enhanced abbreviated MRI (AMRI) in cirrhotic and chronic hepatitis B (CHB) patients for hepatocellular carcinoma (HCC) screening.Materials and methodsSeventy-nine consecutive patients at risk for HCC due to cirrhosis and/or CHB were included in this retrospective study. For each patient, the first gadoxetate disodium-enhanced MRI between 2008 through 2014 was analysed. Two independent readers read an anonymised abbreviated image set comprising axial T1-weighted (W) images with fat saturation in the hepatobiliary phase, 20 minutes or more after gadoxetate injection, and axial T2W single-shot fast spin echo images. Each observation >10 mm was scored as negative or suspicious for HCC. Inter-reader agreement was assessed. A composite reference standard was used to determine the per-lesion diagnostic performance for each reader.ResultsInter-reader agreement was substantial (κ = 0.75). The final reference standard showed 27 HCCs in 13 patients (median 21 mm, range 11-100 mm). The two readers each correctly scored 23 as suspicious for HCC (sensitivity = 85.2%), scored a total of 27 and 32 observations as suspicious for HCC (positive predictive value [PPV] = 85.2% and 71.9%), and scored 83 and 78 observations or complete examinations as negative for HCC (negative predictive value [NPV] = 95.2% and 94.9%).ConclusionsThe AMRI protocol provides higher per-lesion sensitivity and NPV than reported values for ultrasound, the current recommended technique for screening, and similar per-lesion sensitivity and PPV to reported values for complete dynamic contrast-enhanced MRI

Diagnostic per-lesion performance of a simulated gadoxetate disodium-enhanced abbreviated MRI protocol for hepatocellular carcinoma screening.

AimTo evaluate the diagnostic per-lesion performance of a simulated gadoxetate disodium-enhanced abbreviated MRI (AMRI) in cirrhotic and chronic hepatitis B (CHB) patients for hepatocellular carcinoma (HCC) screening.Materials and methodsSeventy-nine consecutive patients at risk for HCC due to cirrhosis and/or CHB were included in this retrospective study. For each patient, the first gadoxetate disodium-enhanced MRI between 2008 through 2014 was analysed. Two independent readers read an anonymised abbreviated image set comprising axial T1-weighted (W) images with fat saturation in the hepatobiliary phase, 20 minutes or more after gadoxetate injection, and axial T2W single-shot fast spin echo images. Each observation >10 mm was scored as negative or suspicious for HCC. Inter-reader agreement was assessed. A composite reference standard was used to determine the per-lesion diagnostic performance for each reader.ResultsInter-reader agreement was substantial (κ = 0.75). The final reference standard showed 27 HCCs in 13 patients (median 21 mm, range 11-100 mm). The two readers each correctly scored 23 as suspicious for HCC (sensitivity = 85.2%), scored a total of 27 and 32 observations as suspicious for HCC (positive predictive value [PPV] = 85.2% and 71.9%), and scored 83 and 78 observations or complete examinations as negative for HCC (negative predictive value [NPV] = 95.2% and 94.9%).ConclusionsThe AMRI protocol provides higher per-lesion sensitivity and NPV than reported values for ultrasound, the current recommended technique for screening, and similar per-lesion sensitivity and PPV to reported values for complete dynamic contrast-enhanced MRI

Bone marrow fat content is correlated with hepatic fat content in paediatric non-alcoholic fatty liver disease.

AimTo investigate the relationship between bone marrow fat content and hepatic fat content in children with known or suspected non-alcoholic fatty liver disease (NAFLD).Materials and methodsThis was an institutional review board-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant, cross-sectional, prospective analysis of data collected between October 2010 to March 2013 in 125 children with known or suspected NAFLD. Written informed consent was obtained for same-day research magnetic resonance imaging (MRI) of the lumbar spine, liver, and abdominal adiposity. Lumbar spine bone marrow proton density fat fraction (PDFF) and hepatic PDFF were estimated using complex-based MRI (C-MRI) techniques and magnitude-based MRI (M-MRI), respectively. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SCAT) were quantified using high-resolution MRI. All images were acquired by two MRI technologists. Hepatic M-MRI images were analysed by an image analyst; all other images were analysed by a single investigator. The relationship between lumbar spine bone marrow PDFF and hepatic PDFF was assessed with and without adjusting for the presence of covariates using correlation and regression analysis.ResultsLumbar spine bone marrow PDFF was positively associated with hepatic PDFF in children with known or suspected NAFLD prior to adjusting for covariates (r=0.33, p=0.0002). Lumbar spine bone marrow PDFF was positively associated with hepatic PDFF in children with known or suspected NAFLD (r=0.24, p=0.0079) after adjusting for age, sex, body mass index z-score, VAT, and SCAT in a multivariable regression analysis.ConclusionBone marrow fat content is positively associated with hepatic fat content in children with known or suspected NAFLD. Further research is needed to confirm these results and understand their clinical and biological implications