Magnetic resonance imaging in pancreatitis.

Pancreatitis can occur in acute and chronic forms. Magnetic resonance imaging (MRI) plays an important role in the early diagnosis of both conditions and complications that may arise from acute or chronic inflammation of the gland. Standard MRI techniques including T1-weighted and T2-weighted fat-suppressed imaging sequences together with contrast-enhanced imaging can both aid in the diagnosis of acute pancreatitis and demonstrate complications as pseudocysts, hemorrhage, and necrosis. Combined use of MRI and MR cholangiopancreatography can show both parenchymal findings that are associated with chronic pancreatitis including pancreatic size and signal and arterial enhancements, all of which are diminished in chronic pancreatitis. The degree of main pancreatic duct dilatation and/or the number of side branch ectasia determines the diagnosis of chronic pancreatitis and its severity. In this paper, we report the spectrum of imaging findings of acute and chronic pancreatitis on MRI and MR cholangiopancreatography.

Magnetic resonance imaging in pancreas transplantation.

Magnetic resonance imaging (MRI) plays an important role in the evaluation of pancreas transplantation. Standard MRI, magnetic resonance angiography, and MR cholangiopancreatography can demonstrate the changes of the anatomy after transplantation. Vascular complications are assessed by MR angiography. Magnetic resonance cholangiopancreatography reveals ductal changes resulting from acute and/or chronic rejection and determines leaks with the use of a secretin-stimulated MR cholangiopancreatography. Serial contrast-enhanced MRI may detect the diminished perfusion that is related to the graft rejection or vascular complications. In this paper, we reviewed types of pancreas transplantation procedures, complications that arise in a short and/or a long term after the transplantation, and their assessment by MRI.

Fat containing HCC: findings on CT and MRI including serial contrast-enhanced imaging.

RATIONALE AND OBJECTIVES: The purpose of this article is to review the spectrum of computed tomography (CT) and magnetic resonance imaging (MRI) findings of fat containing hepatocellular carcinoma (HCC), including serial contrast-enhanced imaging. MATERIALS AND METHODS: Imaging findings of 10 fat-containing HCCs on CT (n = 2) or MRI (n = 3) or on both CT and MRI (n = 5) were retrospectively reviewed in 9 patients. Both techniques included serial contrast enhanced imaging in arterial, portal venous, and late venous phases. RESULTS: On non-contrast CT, fat containing HCC was either homogeneously hypodense (n = 6) or of mixed density (n = 1). The density values ranged between -11 and 9 HU. On MRI, homogenous (n = 4) or heterogeneous (n = 4) signal loss was observed on T1-weighted out-of-phase images as compared to in-phase images. Enhancement patterns on serial contrast-enhanced CT and MRI included: arterial enhancement indistinguishable from the liver with venous wash out (n = 2), arterial capillary blush with venous phase fading (n = 2), and heterogeneous arterial enhancement with unenhanced foci and venous phase wash out of enhancements. Larger lesions had late capsular enhancement. CONCLUSIONS: Fat containing HCC has spectrum of imaging findings on CT and MRI. MRI with chemical shift technique depicts the fat content. Arterial contrast enhancement with venous washout or fading may help for the diagnosis of HCC in inconclusive cases.

Comparison of liver biopsy and noninvasive methods for diagnosis of hepatocellular carcinoma.

BACKGROUND & AIMS: Current management guidelines for hepatocellular carcinoma (HCC) do not require biopsy to prove the diagnosis. We evaluated our experience of patients with liver disease and hepatic lesions suspicious for HCC who underwent both fine-needle aspiration and core biopsy and correlated the results with those from commonly used noninvasive approaches. METHODS: We retrospectively reviewed the outcomes of a series of patients undergoing biopsy because of a suspicion of HCC and compared sensitivity, specificity, and predictive value of biopsy with existing noninvasive methods for diagnosing HCC. RESULTS: HCC was diagnosed by biopsy in 74 (63%) of 118 cases, and an additional 10 were found to have HCC on follow-up. Patients with positive biopsy results had significantly higher serum alpha-fetoprotein levels (median, 57 vs 12; P = .014) than those with negative biopsies, although these 2 groups were otherwise similar with regard to tests of liver function, lesion size on imaging, and Child-Pugh class. No patient developed evidence of tumor spread along the needle track after biopsy. We compared the diagnosis of HCC by biopsy with noninvasive diagnostic criteria advocated by the European Association for the Study of the Liver and those used by the United Network for Organ Sharing. Compared with criteria of the European Association for the Study of the Liver and the United Network for Organ Sharing, biopsy had greater sensitivity, specificity, and predictive value. CONCLUSIONS: We recommend a greater role for image-guided biopsy of lesions greater than 1 cm clinically suspicious for HCC to allow adequate treatment planning because the risks of biopsy appear small and the potential benefits significant. Obtaining material for both cytologic and histologic examination at biopsy maximizes the diagnostic yield.