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Purpose To clarify the optimal iodine dose of contrast material for 3-dimensional multidetector-row CT angiography (3D-MDCTA) of the venous vasculature of the liver using volume rendering technique. Materials and methods This study included 103 patients who were randomly assigned to 5 contrast-enhanced MDCT protocol groups with different body-weight-tailored doses of contrast material: 500, 600, 630, 650, and 700 mgI/kg body weight. The arterial, portal, and hepatic parenchymal phases were obtained to evaluate enhancement values of the aorta, portal vein, and hepatic vein. Visualization of the portal and hepatic veins on the volume-rendering images of 3D-MDCTA was evaluated using a 5-point grade. Dunnett's test was used to compare the mean enhancement value and mean grades of image quality (700 mgI/kg dose group was control). Results The mean enhancement values of portal and hepatic vein in the group with 500 and 600 mgI/kg were significantly lower than those of the control group. During visual assessment, a significantly lower mean grades were observed in 500 mgI/kg groups for the portal vein, and 500 and 600 mgI/kg groups for hepatic vein. There were no significant intergroup differences in mean enhancement values and visual assessment among the groups using 630 mgI/kg or more. Conclusion Iodine doses of 630 mgI/kg was recommended for 3D-MDCTA.

Stereotactic body radiotherapy (SBRT) for oligometastases represents a recent trend in radiation oncology. While abundant data are available regarding the use of SBRT for the treatment of lung or liver oligometastases from various retrospective series and prospective trials, relatively little information has been accumulated for the treatment of oligometastases at sites other than the lungs and liver, particularly for sequential oligometastases in multiple organs. Oligometastases with primary lesions controlled is called “oligo-recurrence.” We describe herein the case of a lung cancer patient who developed repeated oligo-recurrence at multiple sites that were each controlled by radical radiotherapy and achieved long-term survival and discuss the merits of locally aggressive radiotherapy for this type of disease condition with reviewing the literature. Although further investigation should be undertaken to clarify the benefits, objectives, and methods of SBRT for the treatment of oligometastases, we believe utilization of SBRT may be worthwhile for patients with remote metastases who hope for treatment to acquire better local control and possible longer survival.

Purpose: To elucidate the natural history of hypovascular nodules that appear hypointense on hepatocyte-phase gadoxetic acid-enhanced MR images by focusing on hypervascularization over time. Materials and Methods: In this study, 135 hypovascular nodules revealing no gadoxetic acid uptake in 53 patients were examined. All nodules were retrospectively examined using serial follow-up computed tomography (CT) and MRI examinations until hypervascularity was observed on arterial-phase dynamic CT or gadoxetic acid-enhanced MR images, or on CT during hepatic arteriography. Logistic regression analysis was used to investigate the association between hypervascularization and MR findings including a presence of fat assessed by a signal drop on opposed-phase T1-weighted images. Results: Of the 135 nodules, 16 underwent hypervascularization. The size of the nodules and the presence of fat in the nodules were independent indicators of hypervascularization. The 1-year cumulative risk of hypervascularization was 15.6%. This risk was significantly increased in the case of nodules >10 mm (37.6%, P < 0.01) and fat-containing nodules (26.5%, P < 0.01). Conclusion: Hypovascular nodules that appear hypointense on hepatocyte-phase gadoxetic acid-enhanced MR images may progress to conventional hypervascular hepatocellular carcinoma. Nodules more than 10 mm in diameter and containing fat are at high risk for developing hypervascularization. J. Magn. Reson. Imaging 2011;. © 2011 Wiley-Liss, Inc.

PURPOSE To retrospectively determine the findings of gadoxetic acid-enhanced magnetic resonance imaging (MRI) to distinguish hemangioma and metastasis of the liver. MATERIALS AND METHODS The University's ethics committee approved this retrospective study. We assessed 45 patients without chronic liver disease who underwent gadoxetic acid-enhanced MRI. Diagnosis of 58 metastases and 47 hemangiomas was confirmed using histopathology or multimodality evaluation. Two radiologists independently assessed the following MRI findings of metastasis and hemangioma: their appearance on T2-weighted images (T2WI) and dynamic contrast enhancement patterns after gadoxetic acid administration. The metastasis and hemangioma findings were compared using Fisher exact test. The lesion-to-liver signal intensity ratio on hepatocyte phase was compared using the Mann-Whitney U test. Multivariate analysis was performed to identify independent imaging findings distinguishing the 2 diseases. Receiver operating characteristic analysis was used to estimate the diagnostic ability of gadoxetic acid-enhanced MRI to distinguish metastasis from hemangioma. RESULTS The lesion-to-liver signal intensity ratio was comparable in both diseases. Peripheral-dot enhancement, ring-like, geographic, and moderate late-phase enhancement, rapid contrast filling, and bright signal on T2WI could differentiate between the 2 diseases. In multivariate analysis, bright signal on T2WI (94%-98% in hemangioma and 13%-25% in metastasis) and ring-like enhancement (4% in hemangioma and 58%-60% in metastasis) were the independent findings suggesting hemangioma and metastasis, respectively. The areas under the receiver operating characteristic curves to distinguish metastasis from hemangioma were 0.95 and 0.98 for Reader 1 and 2, respectively. CONCLUSION Reliable findings to distinguish hepatic metastasis from hemangioma on gadoxetic acid-enhanced MRI were ring-like enhancement on arterial-phase images and bright signal on T2WI.

determine the effect of double-dose gadoxetic-acid (Gd-EOB-DTPA) on lesion-liver contrast ratio in arterial- and hepatocyte-phase images and arterial-phase image quality in patients with chronic liver disease.the ethics committee at our institute approved this study. This study included 28 patients (13 with Child-Pugh class A and 15 with class B) with 54 hepatocellular carcinomas. All patients received the standard Gd-EOB-DTPA dose (0.025 mmol/kg bodyweight) and double dose (0.050 mmol/kg bodyweight). The lesion-liver contrast ratio was evaluated in arterial- and hepatocyte-phase images. The artifacts in arterial-phase images were evaluated with a 4-point scale. Wilcoxon signed-rank test were used for comparisons.the hepatocyte-phase lesion-liver contrast ratio after the double dose was significantly higher than that after the standard dose in patients with Child-Pugh class B disease(standard dose vs. double dose; 0.20 ± 0.16 vs. 0.25 ± 0.17; P0.0001); however, the ratio after both the standard and double doses was equivalent in patients with Child-Pugh class A disease (0.35 ± 0.18 vs. 0.35 ± 0.14; P = 0.3038). The double dose significantly increased the arterial-phase lesion-liver contrast ratio (0.34 ± 0.19 vs. 0.58 ± 0.33; P0.0001). The artifacts in the arterial-phase images were more prominent after the standard dose (2.7 vs. 2.4 for reader 1, 2.8 vs. 2.4 for reader 2; P = 0.0195 and 0.0010).administration of double dose of Gd-EOB-DTPA provided better arterial enhancement of hepatocellular carcinomas in patients with chronic liver disease, and also improved the lesion-liver contrast in hepatocyte-phase images in patients with Child-Pugh class B disease.

Background and purpose The aim of this study was to define the effects of voluntary anal contraction on prostate motion in an experimental setting. Materials and methods Thirty-eight patients (median age, 76years) with prostate cancer underwent thin-slice computed tomography (CT) in the vicinity of the prostate before and after active anal contraction. Three-dimensional displacement of the pelvis and prostate was measured. Results Mean (±standard deviation, SD) overall displacement of the prostate due to anal contraction was 0.3±1.4mm to the right, 9.3±7.8mm to the anterior, and 5±4mm to the cranial direction. Mean displacement of the pelvis was 0.5±1.8mm to the right, 4.1±7.1mm to the anterior, and 1±3mm to the cranial direction. Mean displacement of the prostate relative to the pelvis was 0.1±1.1mm to the left, 5.2±3.3mm to the anterior, and 4±4mm to the cranial direction. Conclusions Voluntary anal contraction within an experimental setting induces large prostate and bone motion, mainly in the anterior and cranial directions. The frequency and magnitude of actual anal contractions during radiotherapy for prostate cancer need to be determined.