Lobar decrease in ^99mTc-GSA accumulation in hilar cholangiocarcinoma

Hilar cholangiocarcinoma can obstruct hepatic ducts and involve the portal veins. Both biliary stasis and decrease in portal venous flow are known to reduce ^99mTc-diethylenetriamine pentaacetic acid-galactosyl human serum albumin (GSA) accumulation. The specific relationship between these pathological conditions due to hilar cholangiocarcinomas and ^99mTc-GSA accumulation has never been clarified. Methods: Sixteen patients with hilar cholangiocarcinomas who underwent ^99mTc-GSA liver scintigraphy were reviewed. The relationship between significant decrease in ^99mTc-GSA accumulation and lobar biliary stasis, or decrease in the portal venous flow, was evaluated. Average counts of region of interest placed in both right and left lobes were compared in the same transaxial SPECT section. Count ratios of right and left lobes were calculated. Results: Significant lobar decrease in ^99mTc-GSA accumulation was observed in 6 of the 16 patients. Ipsilateral portal venous stenosis or obstruction was seen in all these 6 patients, whereas ipsilateral portal venous stenosis or obstruction was seen in only 1 of the other 10 patients. Symmetric bile duct dilatation was seen in 13 patients, and asymmetric bile duct dilatation was seen in 3. Lobar decrease in ^99mTc-GSA accumulation correlated well with decrease in ipsilateral portal venous flow (P< 0.0005). The count ratio was significantly reduced when unilateral portal venous flow decreased (P < 0.05). Conclusion: Using ^99mTc-GSA liver scintigraphy, we can predict lobar decrease in ipsilateral portal venous flow and monitor hepatic functional lateralities in patients with hilar cholangiocarcinomas.