Intraportal venous flow distribution: evaluation with single breath-hold ECG-triggered three-dimensional half-Fourier fast spin-echo MR imaging and a selective inversion-recovery tagging pulse.

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the intraportal blood flow distribution from splenic and superior mesenteric veins with an unenhanced MR angiographic technique using single breath-hold ECG-triggered three-dimensional (3D) half-Fourier fast spin-echo sequence and selective inversion-recovery tagging pulse. SUBJECTS AND METHODS: Seventeen healthy volunteers were included in this prospective study. After obtaining regular single breath-hold ECG-triggered 3D half-Fourier fast spin-echo images without applying a tagging pulse, we placed the selective inversion-recovery tagging pulse on the superior mesenteric vein (TAG-A), the splenic vein (TAG-B), or on both (TAG-C) to study the inflow correlation of tagged or marked blood into the portal vein. MR images were evaluated subjectively by three reviewers. RESULTS: On MR images obtained using the TAG-A pulse to suppress the signal flow from the superior mesenteric vein into the portal vein, the most common pattern of signal loss was observed on the right half of the main portal vein (8/17 subjects). Conversely, on the MR images obtained using the TAG-B pulse, signal loss of the left half of the main portal vein was the most common pattern (11/17 subjects). Signal reduction from the splenic venous flow in the left portal vein was significantly greater than that from the superior mesenteric venous flow (p<0.05). CONCLUSION: The unenhanced MR angiographic technique using single breath-hold ECG-triggered 3D half-Fourier fast spin echo with selective inversion-recovery tagging pulse has the potential to assess the intraportal blood flow distribution from the splenic and superior mesenteric veins.