Role of per-rectal portal scintigraphy in long-term follow-up of congenital portosystemic shunt

Abstract

Congenital portosystemic shunt (CPSS) has the potential to cause hepatic encephalopathy and thus needs long-term follow-up, but an effective follow-up method has not yet been established. We aimed to evaluate the importance of per-rectal portal scintigraphy (PRPS) for long-term follow-up of CPSS. We retrospectively examined shunt severity time course in patients (median: 9.6 y, range: 5.2-16.6 y) with intrahepatic (n = 3) or extrahepatic (n = 3) CPSS by using blood tests, ultrasonography or computed tomography, and PRPS. Per-rectal portal shunt index (cutoff: 10%) was calculated by PRPS. PRPS demonstrated that the initial shunt index was reduced in all intrahepatic cases (from 39.7 ± 9.8% (mean ± SD) to 14.6 ± 4.7%) and all extrahepatic cases (from 46.2 ± 10.9 to 27.5 ± 12.6%) during the follow-up period. However, ultrasonography and computed tomography disclosed different shunt diameter time courses between intrahepatic and extrahepatic CPSSs. Initial shunt diameter (5.8 ± 3.5 mm) reduced to 2.0 ± 0.3 mm in intrahepatic cases, but the initial diameter (6.3 ± 0.7 mm) increased to 10.6 ± 1.0 mm in extrahepatic cases. All patients had elevated serum total bile acid or ammonia levels at initial screening, but these blood parameters were insufficient to assess shunt severity because the values fluctuate. PRPS can track changes in the shunt severity of CPSS and is more reliable than ultrasonography and computed tomography in patients with extrahepatic CPSS.