99m Tc-GSA SPECT/CT fusion imaging for hepatectomy candidates with extremely deteriorated ICG value

Purpose The value of indocyanine green (ICG) test is negatively affected in patients with intrahepatic shunt, ICG excretory defect, or jaundice. This study evaluated 99m Tc-GSA SPECT/CT fusion imaging for assessing liver function in patients with severely deteriorated ICG values. Materials and methods Thirteen hepatectomy candidates with ICG retention rates over 40% were retrospectively analyzed. The ICG clearance rate (KICG) and estimated KICG obtained by 99m Tc-GSA scintigraphy (KGSA) were used to evaluate preoperative whole liver function. Remnant liver function was assessed using the remnant (rem) KICG (= KICG × volumetric rate) and remKGSA (= KGSA × functional rate) indices; hepatectomy was considered unsafe for values < 0.05. The correlations of remKICG and remKGSA with postoperative mortality and morbidity were also investigated. Results KGSA values were significantly greater than KICG values (median: 0.12 vs. 0.059; p < 0.01); remKGSA values were greater than remKICG values in all patients (median: 0.107 vs. 0.0413; p < 0.01). Hepatectomy was considered unsafe in 70% patients using remKICG, and in none of those using remKGSA; liver failure or postoperative mortality did not occur. Conclusions 99m Tc-GSA SPECT/CT fusion imaging enables more accurate liver function assessment than the ICG test in patients with severely deteriorated ICG values.