The Feasibility of Using Volumetric Phase-Contrast MR Imaging (4D Flow) to Assess for Transjugular Intrahepatic Portosystemic Shunt Dysfunction

Purpose To demonstrate the feasibility of detecting patency, stenosis, or occlusion of transjugular intrahepatic portosystemic shunt (TIPS) with four-dimensional (4D) flow MR imaging. Materials and Methods Sequential adult patients with TIPS were eligible for enrollment. Volumetric phase-contrast sequence was used to image TIPS. Particle tracing cine images were used for qualitative assessment of stenosis. TIPS was segmented to generate quantitative data sets of peak velocity. Segmentation and quantitative measurement of flow throughout an entire TIPS defined technical success. Doppler US was used for comparison. Venography, when available, and 6-month clinical follow-up were used as reference standards. Results 4D flow MR imaging was performed in 23 patient encounters and was technically successful in 16/23 (69.6%) encounters. Three cases demonstrated both focal turbulence and abnormal velocities (> 190 cm/s or < 90 cm/s) on 4D flow and had venography-confirmed stenosis (true-positive cases). Seven cases had normal velocities and no turbulence on 4D flow, and all were confirmed negative with clinical follow-up or venography (true-negative cases). Six cases had discordant 4D flow results, with abnormal velocities but no turbulence or focal turbulence but normal velocities. All 6 discordant cases had no evidence of dysfunction during 6-month follow-up. Conclusion 4D flow MR imaging can detect TIPS patency and stenosis, but further investigation is required before it can be used to assess for TIPS dysfunction.