Characterization of multiple acquired portosystemic shunts using transplenic portal scintigraphy

We describe the scintigraphic patterns observed in 14 patients with confirmed multiple portosystemic shunts imaged via transplenic portal scintigraphy. Parameters evaluated included presence of multiple anomalous vessels, presence of hepatofugal flow caudal to spleen, and/or to cranial margin of the kidneys, slow absorption resulting in longer spleen to heart transit time, and presence of biphasic or fragmented bolus. Twenty-eight additional patients, 14 with a confirmed single portocaval and 14 with a portoazygos shunt, were used for comparison. Nine of 14 (64.3%) patients with multiple shunts had multiple vessels, five (35.7%) had a biphasic bolus, 13 (92.9%) had hepatofugal flow caudal to the cranial margin of the kidneys. In all single portocaval shunts, a single anomalous vessel was identified. None had hepatofugal flow caudal to the border of the kidneys. Among portoazygos shunts, 4/14 (28.6%) had flow caudal to the injection site. Six portoazygos and one portocaval shunts had biphasic bolus. Median transit time from spleen to heart was significantly longer (1.9 s) in patients with multiple shunts than in patients with a portocaval shunt (1.0 s), but not in patients with a portoazygos shunt (1.3 s). Although a distinct plexus of anomalous vessels is not detected in all patients with multiple shunts imaged using transplenic portal scintigraphy, findings of hepatofugal flow caudal to the margin of the kidneys, and longer transit time compared with single portocaval shunts were characteristic. Flow caudal to the splenic injection site but cranial to the kidneys and biphasic bolus can also be seen with a single congenital shunt.