Transjugular intrahepatic portosystemic shunt: Accuracy of helical CT angiography in the detection of shunt abnormalities

PURPOSE: To determine the sensitivity, specificity, and accuracy of helical computed tomographic (CT) angiography in the detection of transjugular intrahepatic portosystemic shunt (TIPS) stenoses or occlusions. MATERIALS AND METHODS: Thirty-seven patients underwent 50 helical CT angiographic examinations and, within 2 weeks of each examination, portography with measurement of the portosystemic pressure gradient. Helical CT angiograms were independently interpreted by three radiologists who were blinded to the results of portography. Results of helical CT angiography and portography were compared. Sensitivity and specificity of helical CT angiography were separately calculated for the demonstration of morphologic abnormalities and the determination of their hemodynamic significance. RESULTS: Of the 50 portograms, 31 (62%) demonstrated morphologic TIPS abnormalities, 24 (77%) with and seven (23%) without elevated portosystemic pressure gradients. Helical CT angiograms correctly demonstrated 30 (97%) of the 31 morphologic abnormalities and allowed correct diagnosis of 22 (92%) of the 24 hemodynamically significant abnormalities. Nineteen (38%) portograms were normal, helical CT angiograms correctly demonstrated the absence of abnormality in 17 (90%) of these cases. Sensitivity and specificity of helical CT angiography for all morphologic abnormalities were 97% and 89%, respectively, and, for hemodynamically significant abnormalities, 92% and 77%. CONCLUSION: Helical CT angiography holds promise as a screening modality for the detection of TIPS stenoses or occlusions.