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Objectives: The objective of this study was to determine the optimal scan delay quantitatively and qualitatively in cerebral CT angiography (CTA) with a test injection method at the circle of Willis (cW). Methods: 66 consecutive patients suspected of having unruptured intracranial aneurysms underwent CTA using 40 ml of 370 mg iodine ml−1 contrast material (CM). After the time until CM arrival at the cW (TcW) was calculated, scan delay was divided into three groups according to TcW and scan duration (SD) between the second cervical vertebra and cW as follows: [(TcW+6)–SD] in 21 patients (Group A); [(TcW+8)–SD] in 23 patients (Group B); and [(TcW+10)–SD] in 22 patients (Group C). Arterial and venous attenuation in the intracranial vessels was measured. Mean attenuation values were compared quantitatively. The arterial enhancement and venous overlap at the cW and above the cW were qualitatively compared among the three groups. Results: Mean arterial attenuation in Groups B and C was significantly higher than that in Group A. Mean venous attenuation in Group C was significantly higher than those in Groups A and B. Arterial enhancement above the cW showed a significant difference between Groups A and C, and at the cW between Groups A and B, and Groups A and C. There was a significant difference in venous overlap among the three groups, except for that at the cW between Groups B and C. Conclusions: Setting scan delay as [(TcW+8)–SD] s can produce the best performance both quantitatively and qualitatively. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to examine attenuation values in the central vein and perivenous artefacts at the subclavian vein in cervical CT angiography (CTA) when using 40ml contrast material (CM) followed by different volumes (25ml vs 40 ml) of saline flush (SF). Methods: 61 patients underwent CTA between the aortic arch (AA) and distal to the circle of Willis (cW). After calculating test-bolus time to peak enhancement at the cW (Tc), scanning delay was represented as [(Tc + 4) - scan duration between AA and cW] s. 28 patients (Group A) received 40 ml of 370mg iodine (I) ml-1 CM followed by 25 ml of SF, and 33 patients (Group B) received the same CM followed by 40 ml of SF, both administered through the right antecubital vein. Arterial attenuation was measured at seven points in the aorto-carotid artery and at three points in the vertebrobasilar artery. Venous attenuation in the central vein was measured at four points. Mean attenuation values were analysed quantitatively. Axial and post-processing threedimensional images were assessed qualitatively. Results: When Groups A and B were compared, there were no differences in the mean attenuation values in either the aorto-carotid artery (p=0.78) or the vertebrobasilar artery (p=0.82). Mean venous attenuation values were lower (p=0.002) in Group B than in Group A. Although the qualitative assessment of arterial images showed no differences between the two groups overall, perivenous artefacts at the subclavian vein were assessed as less prominent (p<0.01) in Group B. Conclusions: When compared with CTA followed by 25 ml of SF, CTA followed by 40 ml of SF can reduce venous attenuation values and perivenous artefacts at the subclavian vein. [ABSTRACT FROM AUTHOR]

We successfully created a percutaneous transhepatic portacaval shunt under ultrasonography (US) guidance in a 46-year-old man with refractory ascites. The shunt was created to salvage an attempt to create a transjugular intrahepatic portosystemic shunt (TIPS) that failed because of the elevated level of portal vein bifurcation due to alcoholic liver cirrhosis. Under US guidance, we simultaneously punctured the right branch of the portal vein and the inferior vena cava (IVC) using a two-step biliary drainage set. An Amplatz gooseneck snare was introduced transjugularly to retrieve the percutaneously inserted guidewire. The intrahepatic tract between the portal vein and the IVC was dilated using a balloon catheter, and a stent was placed in the tract. The patient showed complete resolution of ascites at discharge. We assume that our method is an alternative method for TIPS creation in patients with inadequate anatomical relations between the portal vein branches and the hepatic veins. This approach is thought to be feasible for patients with occluded or small hepatic veins. [ABSTRACT FROM AUTHOR]

Papillary renal cell carcinoma (PRCC) is the second most common class of renal cell carcinoma. PRCCs have typically been reported to demonstrate homogeneous, low-intensity signals in T2-weighted magnetic resonance imaging (MRI) scans and rarely high-intensity signals. We reported two cases of PRCC with high signal intensity on T2-weighted images. These two cases were accompanied by a small amount of hemosiderin deposition and intense edema in the tumor. [ABSTRACT FROM AUTHOR]

Background: Although fast acquisition of multidetector-row computed tomography (MDCT) can make it possible to acquire sufficient early vascular enhancement using small volumes and high concentrations of contrast material (CM), there are still some problems with nephrotoxicity and costs related to CM. Purpose: To compare the qualitative and quantitative performance in cervicocranial CT angiography (CTA) using two different iodine volumes and concentrations of CM. Material and Methods: CTA ranging from the aortic arch (AA) to distal to the circle of Willis (cW) was performed on a 32-MDCT system. Fifty-eight patients were randomly divided into two groups: group A (29 patients) received 60 ml of 300 mg I/ml CM, and group B (the other 29 patients) received 40 ml of 370 mg I/ml CM. Time to peak arterial enhancement at cW (Tc) was calculated. As scan speed was 96.9 mm/s and injection rate was 4.0 ml/s, scanning delay was individually decided according to Tc and scan duration between AA and cW. Arterial attenuation along the z-axis at eight points in the carotid-cerebral artery and venous attenuation of the internal jugular vein (IJV) at carotid bifurcation were measured. Mean attenuation values were then quantitatively analyzed. Postprocessing images were qualitatively assessed. Results: Arterial attenuation profiles revealed maximum attenuation at the distal common carotid artery in both groups. Although there were no significant differences in mean arterial attenuation in group A versus group B (402±70 HU vs. 407±67 HU; P=0.78), venous attenuation of the IJV was lower in group B than in group A (114±57 HU vs. 224±81 HU; P<0.001). Although arterial images demonstrated no difference qualitatively between the two groups, the venous contamination of IVC was less prominent in group B. Conclusion: Although a different amount of CM was administered in both groups, quantitative and qualitative arterial images did not show significant differences between the two groups. [ABSTRACT FROM AUTHOR]