MATERIALS AND METHODS. One hundred one cirrhotic patients (male:female = 69:32) with hypoattenuating nodules observed on initial portal or equilibrium phase CT images were retrospectively evaluated by follow-up CT performed 6–66 months after the initial CT examination. Depending on the background nodularity, patients were separated into macronodular (n = 33, 288 nodules) and micronodular (n = 68, 346 nodules) cirrhotic groups. Each nodule was categorized as category I (enlarged) or category II (stable). Nodule categories were correlated with the initial lesion size and the pattern of background cirrhosis.

RESULTS. The frequency of category I nodules was higher in patients with micronodular cirrhosis (40%) than in those with macronodular cirrhosis (27%) (p = 0.001). Category I nodules were significantly larger than category II nodules in patients with micronodular cirrhosis (p < 0.001). The doubling times of category I nodules had no statistical difference between patients with micronodular or macronodular cirrhosis (p = 0.954). Of the category I nodules in patients with micronodular cirrhosis, 8.6% showed malignant changes.

CONCLUSION. More careful attention should be paid to large nodules in patients with micronodular cirrhosis because of the potentially greater risk of malignancy, and small hypoattenuating nodules should be more often followed up in shorter intervals than large nodules.

MATERIALS AND METHODS. Sixty-two new HCCs appearing after percutaneous radiofrequency ablation in 59 patients who underwent follow-up multiphase CT were retrospectively identified. The volume of the new HCCs at follow-up CT was measured on a PACS monitor with an area measuring tool and summation-of-areas technique. We calculated tumor volume doubling time and tumor diameter doubling time. The growth rate was represented by tumor volume doubling time. We also used stepwise multiple linear regression analysis to evaluate the relation between clinical variables and tumor volume doubling time.

RESULTS. Mean baseline and follow-up tumor volumes were 580 mm³ (range, 85–13,861 mm³) and 2,072 mm³ (range, 535–35,937 mm³). Mean baseline and follow-up tumor diameters were 9.9 mm (range, 5.5–29.8 mm) and 15.0 mm (range, 10.1–40.9 mm). Mean tumor volume and tumor diameter doubling times were 75 days (range, 21–209 days) and 219 days (range, 57–897 days). Volume doubling times of baseline tumors with a diameter of 1 cm or less were significantly shorter than those of the larger baseline tumors (mean, 55 vs 88 days; p = 0.024).

CONCLUSION. The growth rate of new HCCs after percutaneous radiofrequency ablation was higher than that reported in natural outcome studies of untreated HCCs. The results of our study suggest that a shorter follow-up interval for imaging, 2.5 months (75 days), is appropriate.

CONCLUSION. MR cholangiopancreatography is the best noninvasive tool for the diagnosis and assessment of biliary complications.

CONCLUSION. The spectrum of MRI and MRCP findings in HIV-infected patients includes acute or chronic hepatitis (or both), pancreatitis, cholangitis, acalculous cholecystitis, and biliary strictures that may resemble primary sclerosing cholangitis. The presence of segmental extrahepatic biliary strictures is characteristic of AIDS cholangiopathy.

MATERIALS AND METHODS. Ninety-nine patients underwent liver CT before; immediately after (< 2 weeks); and 2, 6, and 12 months after liver transplantation. Two radiologists retrospectively reviewed the CT images to determine the grade of the portosystemic collaterals and the volume of the spleen. Portosystemic collaterals were categorized as esophageal, paraesophageal, gastric submucosal, gastric adventitial, splenic, mesenteric, or retroperitoneal varices. First, the largest diameter of each varix was determined. Each varix was graded using a 5-point scale according to the number of dilated vessels and the largest diameter. Splenic volume was calculated using a previously reported formula. To determine how varices and splenomegaly develop over time, the grade of varices on each postoperative CT scan was compared with those on the preoperative and immediately prior CT scans. The degree of change of the portosystemic collaterals and change in the splenic volume on CT were correlated with the type of transplantation (deceased-donor-related liver transplantation [DDLT] vs living-donor-related liver transplantation [LDLT]), the transplanted liver weight, and the presence of postoperative adverse events such as rejection and portal or hepatic vein stenosis.

RESULTS. All varices except splenic and retroperitoneal varices and splenic volume were significantly decreased on CT performed within 2 weeks after liver transplantation (p < 0.05). Approximately 2 months after liver transplantation, all varices except the esophageal varices and splenic volume became stable. The type of transplantation and the presence of postoperative adverse events did not affect the degree of change of varices or change in splenic volume. However, the rate of volume reduction of the spleen in LDLT was weakly but significantly correlated with the weight of the transplanted liver (Pearson's correlation coefficient, r = 0.401; p < 0.0001).

CONCLUSION. Most varices and splenomegaly significantly decrease during the early postoperative period (< 2 months) after liver transplantation. Patients with large liver transplants undergo a greater decrease in spleen volume than patients with small liver transplants.

SUBJECTS AND METHODS. Forty potential LDLT donors who ranged in age from 19 to 54 years were prospectively evaluated with preoperative MRCP. MRCP was performed with a 1.5-T magnetic field using T2-weighted PACE TSE sequence. MRCP source data sets were processed with maximum-intensity-projection (MIP) and shaded surface display (SSD) algorithms. Findings were compared with intraoperative cholangiography. Biliary anatomy was classified according to the classification proposed by Huang and colleagues. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRCP for the detection of aberrant biliary anatomy were calculated.

RESULTS. Intraoperative cholangiography and biliary exploration revealed that 27 donor candidates (67.5%) had conventional and 13 (32.5%) had aberrant biliary anatomy. Two donors (5%) had type B biliary anatomy; eight donors (20%), type C; two donors (5%), type D; and one donor (2.5%), unclassified. The sensitivity of MRCP source data sets in differentiating aberrant biliary anatomies from nonaberrant ones was 100%, the specificity was 88.9%, and the accuracy was 92.5%. PPV and NPV were 81.3% and 100%, respectively. The sensitivity of MIP images in differentiating aberrant biliary anatomies was 100%, the specificity was 88.9%, and the accuracy was 92.5%. PPV and NPV were 81.3% and 100%, respectively. The sensitivity, specificity, accuracy, PPV, and NPV of the SSD images in detecting aberrant biliary anatomies were 100%, 77.8%, 85%, 68.4%, and 100%, respectively.

CONCLUSION. Preoperative MRCP using a respiratory navigator-triggered T2-weighted TSE sequence with a PACE technique accurately depicts the biliary anatomy in LDLT donors and may guide intraoperative management of the biliary tract.

MATERIALS AND METHODS. Forty-four liver tumors (14 metastatic lesions, 12 hepatocellular carcinomas, nine hemangiomas, five cholangiocarcinomas, three cases of focal nodular hyperplasia, and one hepatic adenoma) were evaluated with MRE. MRE was performed with a 1.5-T system with a modified phase-contrast gradient-echo sequence to collect axial wave images sensitized along the through-plane motion direction. The tumors were identified on T2- and T1-weighted and gadolinium-enhanced T1-weighted images, and the MRE images were obtained through the tumor. A stiffness map (elastogram) was generated in an automated process consisting of an inversion algorithm. The mean shear stiffness of the tumor was calculated with a manually specified region of interest over the tumor in the stiffness map. The stiffness value of tumor-free hepatic parenchyma was calculated. Statistical analysis was performed on the stiffness values for differentiation of normal liver, fibrotic liver, benign tumors, and malignant tumors.

RESULTS. Malignant liver tumors had significantly greater mean shear stiffness than benign tumors (10.1 kPa vs 2.7 kPa, p < 0.001), fibrotic liver (10.1 kPa vs 5.9 kPa, p < 0.001), and normal liver (10.1 kPa vs 2.3 kPa, p < 0.001). Fibrotic livers had stiffness values overlapping both the benign and the malignant tumors. A cutoff value of 5 kPa accurately differentiated malignant tumors from benign tumors and normal liver parenchyma in this preliminary investigation.

CONCLUSION. MR elastography is a promising noninvasive technique for assessing solid liver tumors. Use of MRE may lead to new quantitative tissue characterization parameters for differentiating benign and malignant liver tumors.

MATERIALS AND METHODS. Thirty-two patients underwent multiphase MDCT because they were suspected of having a hepatic tumor. Patients were assigned to one of the following two groups: group A, 100 mL of 370 mg I/mL of contrast medium injected into a unilateral cubital vein (one-route) via a 20-gauge cannula at a rate of 4 mL/s; or group B, 50 mL of contrast medium injected into the cubital veins bilaterally (two-route) via 24-gauge cannulas at 2 mL/s. Peak contrast enhancement of the liver and abdominal aorta for groups A and B was measured using regions of interest and compared; arrival time of the contrast media was also compared using a bolus-tracking system. Analysis was performed using Wilcoxon's signed rank test.

RESULTS. Peak aortic enhancement of groups A and B was 367 ± 67 H and 361 ± 113 H (p = 0.61, not significant), respectively, and peak hepatic enhancement of groups A and B was 56 ± 11 H and 56 ± 16 H (p = 0.88, not significant), respectively. Mean arrival time to the aorta of group B (19.4 ± 3.4 seconds) was significantly later compared with that of group A (15.5 ± 3.5 seconds) (p = 0.005).

CONCLUSION. The slower two-route injection produced the same aortic and hepatic enhancement as the faster one-route method with faster injection, but the arrival time of the contrast medium was later using the two-route method.

MATERIALS AND METHODS. Thirty-nine patients (18 men and 21 women; mean age, 51.8 years) were referred for MRCP. Multiangled thick-slab breath-hold SSFSE imaging was performed without and with integrated parallel imaging with sensitivity encoding (SENSE). Images were retrospectively reviewed. A 4-point rating scale was used to grade overall image quality and visibility of 10 ductal segments. A Wilcoxon's signed rank test compared the two techniques. Analysis of signal intensities and relative contrast of fluid-filled structures to background tissue on the basis of region of interest was calculated. Differences between the techniques were compared using a Student's t test.

RESULTS. Two-dimensional thick-slab SSFSE with integrated parallel imaging showed a mild but statistically significant increase in the relative contrast (p = 0.01) of ductal segments. Image quality deteriorated slightly with parallel imaging, but the results were not statistically significant (p = 0.06). Parallel imaging improved duct conspicuity of the medial and lateral segments of the left lobe and the posterior segment of the right lobe. However, statistical improvement was achieved only for the medial segment of the left lobe (p = 0.03). The mean scores of the remaining ducts were either unchanged or worse with parallel imaging, but the differences were not significant.

CONCLUSION. Although there was improvement in the relative contrast of bile to background tissue, improvement in overall image quality was not observed with parallel imaging. However, application of parallel imaging to thick-slab SSFSE may improve depiction of the smallest-caliber ducts.

MATERIALS AND METHODS. One hundred one patients enrolled in the study were separated into two groups. Fifty-one patients with 65 hepatocellular carcinomas underwent prospective virtual CT sonography as guidance for radiofrequency ablation. Fifty patients with 63 hepatocellular carcinomas managed with B-mode sonographic guidance were retrospectively selected under the same conditions as the virtual CT sonography group to act as a historical control group.

RESULTS. In the virtual CT sonography group, technically successful ablation was achieved in a single session in 92% (47/51) of the patients and in two sessions in 8% (4/51). In the B-mode sonography group, technical success was achieved in a single session in 72% (36/50) of the patients, in two sessions in 24% (12/50), and in three sessions in 4% (2/50). Treatment analysis showed that the technical success rate after a single treatment session was significantly (p = 0.017) higher for the virtual CT sonography group. The number of treatment sessions was significantly (p = 0.021) lower for the virtual CT sonography group (mean, 1.1 ± 0.1 vs 1.3 ± 0.3 sessions).

CONCLUSION. Virtual CT sonographically assisted radiofrequency ablation is an efficient treatment of patients with hepatocellular carcinoma that is poorly defined on B-mode sonography.