Combined hepatocellular carcinoma-cholangiocarcinoma: report of MR appearance in eleven patients.

PURPOSE: To describe the magnetic resonance imaging (MRI) appearance of hepatic combined hepatocellular-cholangiocarcinoma (cHCC-CC) in 11 patients. MATERIALS AND METHODS: The database of the Department of Pathology was cross-referenced with the MRI database to identify patients with confirmed cHCC-CC who had undergone MRI. Eleven consecutive patients were included (seven female, mean age 57.6 years). All patients were Caucasian. Five of 11 had a clinical history of chronic liver disease. Two radiologists retrospectively analyzed the images in consensus. RESULTS: cHCC-CC was a single mass in 10/11 patients. Margins were well-defined in 6/11. All tumors showed heterogeneous hyperintensity on T2. On postcontrast imaging, 6/11 showed early ring-enhancement (four noncirrhotic), with progressive enhancement in central portions, and 5/11 patients showed a diffuse heterogeneous early enhancement. Three of these five were cirrhotic and displayed partial washout with portions of contrast retention on later phases. Other findings included: late capsule enhancement (two patients), biliary dilatation (one), venous invasion (three), lymphadenopathy (six), and findings of cirrhosis (five). CONCLUSION: cHCC-CC presents most commonly as a single mass. Five of 11 had MR findings of cirrhosis. Clues to the diagnosis were moderately high signal on T2, portions of tumor that show progressive enhancement/contrast retention, and frequent lack of capsule. Early enhancement patterns included early ring-enhancement and diffuse heterogeneous enhancement.

Comparison of the incidence of pancreatic abnormalities between high risk and control patients: prospective pilot study with 3 Tesla MR imaging.

PURPOSE: To compare the incidence of pancreatic abnormalities detected by MR imaging between high-risk patients and control patients. MATERIALS AND METHODS: Forty-one consecutive patients who had two or more first-degree relatives with pancreatic cancer and who were asymptomatic with no clinical evidence of pancreatic cancer were prospectively included in this study. A control group was obtained by reviewing consecutive patients undergoing 3 Tesla (T) MRI examinations for nonpancreatic indications. On MR imaging, the presence of pancreatic abnormalities were evaluated in consensus by two radiologists who were blinded to clinical history. Pancreatic abnormalities were categorized as developmental abnormalities, mass-type lesions, inflammatory disease, and others. RESULTS: Overall, the incidence of pancreatic abnormalities was greater in the high-risk group than in the control group, but not statistically significant (P = 0.244). In the high-risk group, a total of 16 patients (39%) were diagnosed with pancreatic abnormalities, whereas in the control group, 11 patients (25%) were diagnosed with pancreatic abnormalities. Regarding mass-type lesions, there was a significant difference in incidence between the high-risk group, with a total of seven patients (17%), and the control group, with one patient (2%) (P = 0.028). There were no cases of imaging diagnosis of pancreatic cancer or tissue evaluation by surgical pathology in either group. CONCLUSION: Our prospective pilot study demonstrated a higher incidence of mass-type lesions in patients at increased risk for pancreatic cancer.

Management of branch-duct intraductal papillary mucinous neoplasms of the pancreas: observation with MR imaging.

PURPOSE: To evaluate the clinical outcomes of conservative management by observation with MRI of patients with branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs). MATERIALS AND METHODS: Twenty-three consecutive patients, who were followed up by MRI with magnetic resonance cholangiopancreatography (MRCP) over a period of more than 9 months after initial MRI examinations, were enrolled in this study. On MRI, number of lesions, the maximum diameter of BD-IPMNs, lesion location, the presence of associated dilatation of main pancreatic duct (MPD), the presence of enhancing mural nodules within the lesion and the presence of interval change were retrospectively reviewed on initial and follow-up MR images in consensus by two radiologists. All patients were evaluated to search for evidence of malignant progression of disease. RESULTS: The follow-up period ranged from 10 to 96 months (mean, 37 months). On initial MRI with MRCP, a total of 39 lesions were found in 23 patients. The maximum diameter of BD-IPMNs ranged between 6 and 32 mm, with a mean of 12 mm. Thirty-four lesions (87%) of 19 patients remained unchanged in the maximum diameter. Five lesions (13%) of four patients showed an increase in the maximum diameter. Enhancing mural nodules were not found in any individual, neither on the initial MRI study nor on the follow-up studies. There was no patient who had evidence of local aggressive growth of tumor or evidence of metastases to distant sites. CONCLUSION: Our study suggests that branch-duct IPMNs without enhancing mural nodules are essentially benign and should be managed nonoperatively through observation by MRI.

MRI findings in nonalcoholic steatohepatitis: correlation with histopathology and clinical staging.

PURPOSE: To evaluate magnetic resonance imaging (MRI) findings of nonalcoholic steatohepatitis (NASH) and to determine the correlation of MRI findings with histopathology and Mayo End-Stage Liver Disease (MELD) score. MATERIALS AND METHODS: Thirty patients (18 males, 12 females; mean age: 57+/-8.9 years; age range: 35-71 years) with histopathologically proven NASH who underwent MRI examinations between January 2001 and October 2005 were included in the study. Two radiologists retrospectively reviewed all magnetic resonance (MR) examinations in consensus to evaluate the presence and extent of predetermined findings of NASH including liver steatosis, early patchy liver enhancement indicating inflammation and liver fibrosis. The findings detected on MRI were correlated and compared to histopathological findings and MELD score by using nonparametric Spearman correlation coefficient and Kruskal-Wallis analysis of variance. RESULTS: Liver steatosis was observed in 10 of 30 patients; early patchy liver enhancement, in 8 of 30 patients and liver fibrosis in 19 of 30 patients on MR images. Liver fibrosis was reticular in all these patients. There were statistically significant moderate correlations between MRI findings of liver steatosis and histopathologic grades of steatosis (r=0.43; P<.05), and between MRI findings of fibrosis and histopathologic stages of fibrosis (r=0.61; P<.001). Early patchy enhancement did not demonstrate statistically significant correlation with inflammation (P=.28). There was no statistically significant overall correlation between MRI findings of NASH and MELD score. CONCLUSION: MRI findings of liver steatosis and fibrosis in NASH showed moderate correlations with histopathologic grades of steatosis and stages of fibrosis, but MRI findings of NASH did not demonstrate any significant correlations with MELD score.

Imaging strategies to reduce the risk of radiation in CT studies, including selective substitution with MRI.

"When one admits that nothing is certain one must, I think, also admit that some things are much more nearly certain than others." Bertrand Russell (1872-1970) Computed tomography (CT) is one of the largest contributors to man-made radiation doses in medical populations. CT currently accounts for over 60 million examinations in the United States, and its use continues to grow rapidly. The principal concern regarding radiation exposure is that the subject may develop malignancies. For this systematic review we searched journal publications in MEDLINE (1966-2006) using the terms "CT," "ionizing radiation," "cancer risks," "MRI," and "patient safety." We also searched major reports issued from governmental U.S. and world health-related agencies. Many studies have shown that organ doses associated with routine diagnostic CT scans are similar to the low-dose range of radiation received by atomic-bomb survivors. The FDA estimates that a CT examination with an effective dose of 10 mSv may be associated with an increased chance of developing fatal cancer for approximately one patient in 2000, whereas the BEIR VII lifetime risk model predicts that with the same low-dose radiation, approximately one individual in 1000 will develop cancer. There are uncertainties in the current radiation risk estimates, especially at the lower dose levels encountered in CT. To address what should be done to ensure patient safety, in this review we discuss the "as low as reasonably achievable" (ALARA) principle, and the use of MRI as an alternative to CT.

Pancreatic cancer: correlation of MR findings, clinical features, and tumor grade.

PURPOSE: To assess the frequency of occurrence of poorly-marginated and focally-defined pancreatic ductal adenocarcinoma by MRI and to determine whether these appearances correlate with clinical features and histopathological grade. MATERIALS AND METHODS: Institutional review board with waiver of informed consent was obtained for this HIPAA compliant study. A total of 33 patients (16 female, 17 male, mean age = 63.5 +/- 12.8, ranging from 41 to 80 years) with histopathologically-proven pancreatic ductal adenocarcinoma who underwent MR examination between August 2000 and February 2005 were retrospectively evaluated. Clinical data and histopathological tumoral grade were obtained from clinical charts; nine of 33 patients were excluded of the histopathological evaluation since their diagnosis was performed by fine needle aspiration biopsy and it was not possible to obtain the histopathological grade. Two radiologists reviewed all cases independently to identify whether cancers were poorly-marginated or focally-defined. Agreement between radiologists was assessed using the kappa coefficient. The overall correlation between imaging findings, clinical features, and histopathological grade was assessed with contingency tables using the Fisher's exact test. RESULTS: Of the 33 patients, nine (27.2%) were classified as poorly-marginated and 24 (72.8%) as focally-defined. Agreement between the two reviewers was excellent (k = 0.92, 95% confidence interval (CI) = 0.78-1.0). Poorly-marginated cancers exhibited well- to moderately-differentiated histopathology in 71.4% of cases, while focally-defined cancers had well- to moderately-differentiated histopathology in 17.6% of cases, P = 0.02. CONCLUSION: A poorly-marginated appearance of pancreatic ductal carcinoma on MRI is not uncommon. These cancers exhibited statistically significant moderate- to well-differentiated histopathology compared to focally-defined cancers.

Magnetic resonance imaging of pulmonary parenchymal disease using a modified breath-hold 3D gradient-echo technique: initial observations.

PURPOSE: To determine the potential of a modified breath-hold 3D gradient-echo technique for visualizing pulmonary parenchymal diseases. MATERIALS AND METHODS: Twenty-one magnetic resonance imaging (MRI) studies of the lungs were performed in 20 patients (15 male and 5 female; age range, 7.7-86.1 years) with pulmonary diseases comprising non-small-cell, small-cell, and bronchioalveolar carcinomas, endobronchial mucoepidermoid carcinoma, metastases, pneumonia, Wegener's granulomatosis, chronic obstructive pulmonary disease, arterio-venous malformation, and bronchogenic cyst. Confirmation of diagnoses was obtained via histopathology (14 patients) and follow-up (6 patients). MRI studies were performed at 1.5 T before and after administration of gadolinium using a modified volumetric interpolated breath-hold examination (VIBE) sequence. All images were evaluated prospectively regarding lesion detection and characterization. MR findings were correlated with final diagnoses. Retrospective grading (scores, 1-4) was performed for general image quality (rated "poor" to "excellent"); presence of artifacts ("negligible" to "severe"); and imaging quality of pulmonary lesions (conspicuity and contrast on pre- and postgadolinium images). RESULTS: Twenty-three solid pulmonary lesions, 25 infiltrates and segmental atelectases, and 1 cyst were detected and prospectively correctly diagnosed. Sizes ranged from 0.3-10 cm. The mean scores for image quality and presence of artifacts were 3.3 (SD, 0.7) and 1.8 (SD, 0.7), respectively. Conspicuity and contrast of pulmonary lesions received mean scores between 3.0 and 3.8 (SD, 0.4-0.7). CONCLUSION: This MRI technique allows imaging of a wide spectrum of solid and nonsolid pulmonary parenchymal diseases with reproducible high image quality, effective suppression of artifacts, high resolution, and visualization of gadolinium enhancement.