Liver fibrosis, cirrhosis, and cirrhosis-related nodules: Imaging diagnosis and surveillance.

Although biological scores and elastography continue to yield the best results, imaging retains a crucial role in the diagnosis of liver fibrosis and cirrhosis. First, digestive symptoms or biological liver test abnormalities often lead the referring physician to request an abdominal ultrasound, and with an experienced operator, accuracy of ultrasound can reach 85% for the diagnosis of severe fibrosis or cirrhosis. Second, imaging could lead to discovery of nonsymptomatic fibrosis or cirrhosis, with an estimated prevalence of 0.5-2.8% in the population. After diagnosis, imaging is central in the follow-up of cirrhosis. It is used to detect worsening of portal hypertension and hepatocellular carcinoma (HCC). Because many nodules are present in a cirrhotic liver, familiarity with the features of HCC can facilitate noninvasive diagnosis and early and accurate treatment.

Imaging features of rare pancreatic tumors.

The increasing use of abdominal imaging has led to a growing incidence of traditionally uncommon pancreatic tumors. These rare tumors have specific imaging features whose knowledge may heighten confidence in characterization and may avoid unnecessary surgical procedures when imaging findings suggest a benign condition. Computed tomography (CT) is the modality with which rare pancreatic tumors are incidentally detected in the majority of cases. Magnetic resonance imaging (MRI) is often performed as a second line examination for further characterization. This review provides an update on CT and MRI findings of rare tumors of the pancreas.

Diffusion-weighted magnetic resonance imaging in colorectal cancer.

Magnetic resonance imaging (MRI) plays now a major role in patients with colorectal cancer regarding tumor staging, surgical planning, therapeutic decision, assessment of tumor response to chemoradiotherapy and surveillance of rectal cancer, and detection and characterization of liver or peritoneal metastasis of colorectal cancers. Diffusion-weighted MRI (DW-MRI) is a functional imaging tool that is now part of the standard MRI protocol for the investigation of patients with colorectal cancer. DW-MRI reflects micro-displacements of water molecules in tissues and conveys high degrees of accuracy to discriminate between benign and malignant colorectal conditions. Thus, in addition to morphological imaging, DW-MRI has an important role to accurately detect colorectal neoplasms and peritoneal implants, to differentiate benign focal liver lesions from metastases and to detect tumor relapse within fibrotic changes. This review provides a comprehensive overview of basic principles, clinical applications and future trends of DW-MRI in colorectal cancers.

MRI versus histological methods for time course monitoring of steatosis amount in a murine model of NAFLD.

PURPOSE: Hepatic steatosis is an increasingly frequent disease with potentially severe complications. A simple quantification method is required for pretherapeutic studies to allow steatosis monitoring. This study aimed at evaluating steatosis quantification via a standard 1.5T MRI machine in a murine model. MATERIALS AND METHODS: Eleven groups of two rats received a choline methionine deficient diet. MRI was performed at days 0, 2, 4, 5, 6, 7 and 8, and weeks 2, 3, 4 and 5. A phased array surface coil system was used to acquire a GE T1 in- and out-of-phase multi-echo sequence, with neither cardiac nor respiratory synchronization. Steatosis was calculated with the 3-echoes method. Histological quantifications were performed both by optical analysis (percentage of fatty hepatocytes) and by automated measurement of the area of steatosis (AOS). The reference was total intrahepatic triglycerides (TIT). Protocol was approved by the ethic committee. RESULTS: Steatosis without inflammation, increasing with diet duration, was obtained. MRI provided better agreement (intraclass correlation coefficient) with TIT (0.889, p<0.001) than did AOS (0.629, p=0.001) or optical analysis (0.280, p=0.098). MRI permitted closer monitoring of TIT over time than did AOS or optical analysis. By multivariate analysis, MRI was an independent predictor of TIT on first step and ALT on second step. A model combining these 2 variables provided excellent agreement with TIT (0.953, p<0.001) and permitted excellent monitoring of steatosis over time. CONCLUSION: MRI is reliable, easy, fast and superior to histological techniques for the assessment of hepatic steatosis in a murine model.