Evaluation of Portal Hypertension: A Comparison of the Use of Liver Perfusion CT with Wedge Hepatic venous Pressure and Hepatic venous Pressure Gradient

PURPOSE: We compared the hepatic perfusion indices obtained using hepatic perfusion CT with the wedge hepatic venous pressure (WHVP) and hepatic venous pressure gradient (HVPG) to determine the efficacy of the use of liver perfusion CT for the evaluation of portal hypertension. MATERIALS AND METHODS: Thirty-five patients with liver cirrhosis underwent hepatic vein catheterization to measure WHVP and HVPG and underwent a liver perfusion CT examination. Arterial perfusion, portal perfusion, total perfusion and the hepatic perfusion index (HPI) were calculated by the methods described by Miles and Blomley. The overall correlation coefficients (r) between the perfusion indices and WHVP and HVPG were calculated. An additional correlation coefficient of 23 alcoholic cirrhosis patients was calculated. RESULTS: Using Blomley's equation, HPI had a positive correlation with WHVP (r = .471; p < .05) and HVPG (r = .482; p < .05). For the alcoholic liver cirrhosis patients, HPI had a higher positive correlation with WHVP (r = .500; p < .05) and HVPG (r= .539; p < .05) than for the non-alcoholic cirrhosis patients. There was no statistical difference between the use of Miles' equation and Blomley's equation for the evaluation of portal hypertension. CONCLUSION: This preliminary study showed that HPI positively correlated with WHVP and HVPG, especially in alcoholic cirrhosis patients. Liver perfusion CT may be useful in the evaluation of portal hypertension.

The Usefulness of Perfusion CT in Acute Cerebral Ischemic Infarction

PURPOSE: To determine the usefulness of cerebral perfusion computed tomography (CT) in patients with acute cerebral ischemic infarction. MATERIALS AND METHODS: Twelve patients with acute middle cerebral artery infarction underwent conventional CT and cerebral perfusion CT within 25 hours of the onset of symptoms. For each patient, perfusion CT scans were obtained at the levels of the basal ganglia and 1 cm caudal to them. Using special imaging software, perfusion imaging maps for cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to peak (TTP) were created, and the infarcted lesion was evaluated on each map. MTT and TTP delay times were measured in the perfusion defect lesion and symmetric contralateral normal cerebral hemisphere. Lesion size on each perfusion map was determined and compared with the value obtained by diffusionweighted MR imaging (DWMRI). RESULTS: In all patients, perfusion CT maps depicted the perfusion defect lesion, for which the MTT and TTP delay was remarkable. A comparison of lesion size between each perfusion map and DWMR images showed that the closest correlation involved CBF maps (8/12, 67%). On MTT maps, the lesion was larger than at DWMRI, suggesting that MTT mapping can be used to evaluate ischemic penumbra. CONCLUSION: Perfusion mapping facilitates the evaluation not only of the ischemic core and ischemic penumbra, but also of hemodynamic status in the area of the perfusion defect. This finding demonstrates that perfusion CT can be useful for the diagnosis and treatment of patients with acute cerebral ischemic infarction.