Debris-filled biliary system: a difficult diagnosis on MRI and MRCP.

We describe a debris-filled biliary system as a difficult diagnosis using magnetic resonance imaging and magnetic resonance cholangiopancreatography (MRCP). A male patient aged 60 years showed a nonvisualized biliary system due to complete filling with debris. The following imaging features were observed: mild heterogeneity of intermediate signal on T2-weighted, MRCP and T1-weighted images and mild heterogeneous enhancement of periportal tissue on early and late postcontrast images. The absence of simple-appearing bile on T2 or MRCP images made the diagnosis of dilated, debris-filled biliary system challenging.

MRI findings of rapidly progressive hepatocellular carcinoma.

PURPOSE: The purpose of this study is to determine the magnetic resonance imaging (MRI) and patient characteristics in subjects with hepatocellular carcinoma (HCC) that exhibit rapid progression. MATERIALS AND METHODS: In this unblinded retrospective study, initial and follow up MR images were reviewed, before and after rapid progression of HCC, respectively. Rapid progression was defined as a lesion <3 cm which exhibited >3 cm increase in one year or 2 cm increase in 6 months. Patient characteristics and MRI findings were determined using clinical information from the institution clinical information system and records from the Radiology and Pathology Departments, Hepatology Division and Liver Transplant Service of the Department of Medicine. RESULTS: Seven individuals were identified with HCC that showed rapid progression. Five of the patients had underlying hepatitis C, one had alcoholic hepatitis, and one had immunosuppression due to liver transplantation. On initial MRI, six patients had early intense ring enhancing lesions, which rapidly progressed in size. Five patients died within 6 months, one within 1 year after progression despite treatment. Six of the seven patients also had multiple other liver nodules on initial MRI; those that showed ring enhancement rapidly progressed but those without, did not show rapid progression. CONCLUSION: Patients with rapidly progressive HCC had underlying hepatitis C and intense ring enhancement on initial MRI. This group of patients should be evaluated further to determine if they might benefit from early intervention.

Thermoablative treatments for malignant liver lesions: 10-year experience of MRI appearances of treatment response.

OBJECTIVE: The objective of our study was to describe our 10-year experience using MRI to evaluate response to local thermoablative interventions in the treatment of malignant liver lesions. MATERIALS AND METHODS: This retrospective study was conducted from 1998 to 2008. MRI studies were performed at 1.5 and 3 T and were acquired < 4, 4-9, and > 9 months after radiofrequency ablation (RFA), cryoablation, and microwave ablation. MR features were evaluated on the basis of signal intensity on unenhanced T1-weighted images and the presence of ill-defined perilesional enhancement, well-defined lesional enhancement, or washout on contrast-enhanced images. Imaging features were evaluated with all interventional modalities together and separately. RESULTS: The study population was composed of 135 men and 36 women (203 ablated lesions) with a mean age of 65 years (range, 39-78 years). When the data for all treatment methods were combined, well-defined lesional enhancement and washout were significant findings among the resolved and unresolved outcome groups regardless of follow-up time category. After RFA, ablated areas had a tendency to show high signal intensity on T1 images, whereas low signal was seen after cryoablation and a hyperintense rim was seen after microwave ablation. Washout was only depicted 9 months after cryoablation but was seen in 12% of lesions < 4 months after RFA. No difference was appreciated on ill-defined perilesional enhancement with all methods combined or separately. CONCLUSION: MRI findings after ablation are dependent on the treatment modality and the length of time between the procedure and follow-up examination.

Enhancement of abdominal organs on hepatic arterial phase: quantitative comparison between 1.5- and 3.0-T magnetic resonance imaging.

PURPOSE: To compare the extent of enhancement of abdominal organs as shown on subphases of hepatic arterial phase quantitatively between 1.5- and 3.0-T MRI among patients with various abdominal conditions. MATERIALS AND METHODS: A total of 126 patients, of whom 68 were women (age range, 3-82 years; mean age, 48 years) and 58 were men (age range, 6-73 years; mean age, 50 years), were included in the study. Of 126 patients, 98 were scanned at 1.5 T and 28 were scanned at 3.0 T. The presence of one of three predefined subphases of hepatic arterial phase was determined on early post-gadolinium sequence in each patient by two reviewers in consensus. Extent of enhancement of the kidney, pancreas, spleen and liver on these subphases was determined quantitatively by measuring the signal intensities. Mann Whitney-Wilcoxon test was used to compare the contrast enhancement of organs on each subphase between 1.5- and 3.0-T MRI. RESULTS: The kidney, spleen, pancreas and liver demonstrated 1.79- to 2.45-, 1.65- to 1.97-, 1.66- to 1.8- and 1.1- to 2.02-fold higher enhancement on the subphases of hepatic arterial phase at 3.0 T compared to 1.5 T, respectively. The differences in contrast enhancement were significant for the kidney, pancreas and spleen on all subphases between 1.5 and 3.0 T. CONCLUSION: The relative enhancement of the kidney, spleen and pancreas is consistently and significantly higher at 3.0 T than at 1.5 T in matched subphases of hepatic arterial enhancement.

MRI findings of posttraumatic intrahepatic vascular shunts.

PURPOSE: To describe the features of posttraumatic intrahepatic vascular shunts (PIVS) as seen on MRI. MATERIALS AND METHODS: A search was performed for patients with MRI features compatible with PIVS in the Abdominal MRI databases between January 2002 and March 2008. This study was approved by our institutional review board. All patients were imaged using a protocol that included noncontrast T1-weighted and T2-weighted images, and postgadolinium gradient-echo images. RESULTS: Eleven patients (eight men, three women; mean age 55.36 years; range 43-77 years) were identified with PIVS. The following imaging features were observed: dilation of afferent and efferent vessels (five patients), transient hepatic parenchymal blush in a watershed distribution (11 patients), and early opacification of efferent vessels (11 patients). CONCLUSION: Patients with PIVS exhibit features that are distinctive for this entity and include: dilatation of efferent and afferent vessels, transient parenchymal blush, and early opacification of efferent vessels.

Early contrast enhancement of the liver: exact description of subphases using MRI.

PURPOSE: The purpose of this study was to describe the subphases of early post-contrast enhancement of the liver, using vessel enhancement patterns, and correlate these findings with enhancement patterns of abdominal organs. MATERIALS AND METHODS: A total of 114 patients who underwent gadolinium-enhanced abdominal magnetic resonance imaging examinations constituted the final study group, of which 56 were women (age range, 3-94 years; mean, 50 years) and 58 were men (age range, 6-85 years; mean, 54 years). Early post-contrast sequences in all patients were evaluated retrospectively by two reviewers for the determination of the presence of contrast enhancement in predetermined major vessels of the abdomen and qualitative and quantitative extent of enhancement of the renal cortex, spleen, pancreas and liver. Based on the overall findings, subphases of early contrast enhancement of the liver were described and quantitative extent of enhancement of organs was correlated with subphases of early contrast enhancement of the liver. Mann-Whitney U test and one-way unbalanced analysis of variance tests were used for the comparisons. RESULTS: Early hepatic arterial phase was observed in 14/114 patients, mid-hepatic arterial phase in 23/114 patients, late hepatic arterial phase in 33/114 patients, splenic vein only hepatic arterial dominant phase in 20/114 patients and hepatic arterial dominant phase in 24/114 patients. There was an overall association between the subphases of enhancement and the quantitative extent of enhancement for all studied organs (P<.0001). CONCLUSION: The evaluation of vessel and organ enhancement patterns has allowed the characterization of five different subphases in early post-contrast enhancement of the liver. The quantitative extent of enhancement of abdominal organs also demonstrated significant correlation with these five subphases.