AZYGOS BLOOD-FLOW - PHASE-CONTRAST QUANTITATION IN VOLUNTEERS AND PATIENTS WITH PORTAL-HYPERTENSION PREINTRAHEPATIC AND POSTINTRAHEPATIC SHUNT PLACEMENT

Flow volume in the azygos venous system was quantitated with Cine-phas e contrast (PC) velocity mapping in volunteers and compared with patie nts with known portal hypertension, who were referred for transjugular intrahepatic portosystemic shunt (TIPS) placement, Subsequently, the TIPS-induced hemodynamic effects on portal and azygos flow were analyz ed. To assess intra- and intersubject variability, flow in the azygos veins was measured in each of 10 normal subjects at three different ti mes, Subsequently, portal and azygos now was quantitated in 20 patient s with portal hypertension, before and after TIPS placement, All imagi ng was performed on a 1.5-tesla magnetic resonance imaging (MRI) syste m, Azygos now was measured transaxially at the midthoracic level, Cine -PC flow measurements of the main portal vein followed morphological e valuation of the portal venous system with axial and coronal breath-he ld magnet resonance angiogram, Azygos flow in normal subjects was char acterized by high inter- and low intrasubject variability, Azygos flow in patients with portal hypertension was significantly higher (P <.00 1), Following successful TIPS placement in 18 patients, Cine-PC reveal ed a mean decrease in azygos flow of 46.3% (P < .001) and a 134% (P <. 001) increase of portal Bow Reflecting the complexity of portal hemody namics, there was no correlation between the changes in the portal and azygos systems, In 2 patients with early occlusion of TIPS, documente d invasively, portal and azygos flow values remained largely unchanged , Cine-PC enables the noninvasive, quantitative assessment of now with in the azygos venous system, Azygos now was found to be markedly eleva ted in patients with portal hypertension, Combined portal and azygos P C now measurements quantitate the therapeutic effect of TIPS placement .