Usefulness of balanced steady-state free precession for portosystemic shunts prior to balloon-occluded retrograde transvenous obliteration.

AIM: This study visualised portosystemic shunts (PSSs), referring to gastrorenal or splenorenal shunts, on balanced steady-state free precession (bSSFP) imaging and assessed its accuracy compared with contrast-enhanced computed tomography (CECT).

MATERIALS AND

METHODS

Patients with bSSFP and CECT imaging of a PSS prior to balloon-occluded retrograde transvenous obliteration from March 2017 to September 2021 were included. The quality of both images was graded based on whether the entire PSS pathway from the afferent vein to the efferent vein was traceable as "well-visualised," "poorly visualised," or "not visualised." Factors contributing to well-visualised on bSSFP images were investigated, including sex, age, height, weight, diagnosis (gastric varices or hepatic encephalopathy), type of PSS, maximum short-axis diameter of the PSS, signal intensity of the surrounding tissue around the PSS, and motion artifacts. Visualisation of collateral drainage veins of the PSS was also evaluated.

RESULTS

Ten of 22 cases were graded well-visualised, 9 poorly visualised, and 3 not visualised on bSSFP images, whereas all cases were graded well-visualised on CECT. There was a significant difference between the two imaging modalities for well-visualised images (P<.001). Univariate analyses identified signal intensity of the surrounding tissue around the PSS and motion artifacts as factors contributing to well-visualised on bSSFP images (both P<.05). Multivariate analysis also showed that the former factor contributed to well-visualised images (P<.001). Of 30 collateral veins visualised on balloon-occluded retrograde transvenous venography , 13 were seen on bSSFP and 20 on CECT.

CONCLUSION

Though bSSFP imaging is a potential alternative for visualising PSS, it is less effective than contrast-enhanced computed tomography.