Index of convexity:A novel liver function index using Tc-GSA scintigraphy

AIM:To investigate the clinical usefulness of a newly developed index,the "index of convexity(IOC)",for evaluating liver functional reserve using technetium99m-diethylenetriaminepentaacetic acid-galactosylhuman serum albumin(Tc-GSA scintigraphy).METHODS:In total,349 patients underwent Tc-GSA scintigraphy.Dynamic planner images were obtained,and time activity curves of the liver and heart were generated and analyzed.Our focus was on the convex shape of the liver accumulation curve.We developed a method for evaluating the extent of convexity and calculated an index that we named the IOC.Clearance index and receptor index were also calculated.The correlations between each GSA index with other liver function tests and liver histopathology were evaluated.RESULTS:Among the 3 indices generated by TcGSA,the IOC had the highest correlation with all other liver function tests(indocyanine green R15,albumin,prothrombin time,cholinesterase level,platelet count,and total bilirubin level).IOC can also differentiate between normal liver,chronic hepatitis,and liver cirrhosis with highest F ratio among GSA indices as determined by one-way analysis of variance.Receiver operating characteristic analysis demonstrated high diagnostic performance of IOC in the diagnosis of cirrhosis.CONCLUSION:IOC is a very simple and reliable index for assessing liver functional reserve,which may prove to be useful in combination with the indocyanine green test for preoperative assessment of hepatic resection.

Preoperative liver functional volumetry performed by 3D-99mTc-GSA scintigraphy/vascular fusion imaging using SYNAPSE VINCENT: a preliminary study

Aim:The present study was designed to evaluate the feasibility of preoperative liver functional volumetry performed by 3D-technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin(99mTc-GSA)scintigraphy/vascular fusion imaging using SYNAPSE VINCENT and to examine the discrepancy between conventional and functional volumetry.Methods:The study group comprised 15 patients who underwent preoperative 3-dimensional(3D)-99mTc-GSA scintigraphy/vascular fusion imaging using SYNAPSE VINCENT software before hepatectomy between July 2014 and August 2015.The diagnosis was hepatocellular carcinoma(n=4),metastatic liver tumor(n=10),or intrahepatic cholangiocarcinoma(n=1).Right hepatectomy was performed in 2 patients,left hepatectomy in 3 patients,right posterior sectionectomy in 3 patients,segmentectomy in 2 patients,and partial hepatectomy in 4 patients.99mTc-GSA scintigraphy and computed tomography(CT)were performed to construct 3D-99mTc-GSA scintigraphy/vascular fused images.The conventional volume ratio of the planned resection region without tumor(%CT),and the functional volume ratio of the planned resection region without tumor(%GSA)were calculated.The discrepancy ratio was calculated as follows:discrepancy ratio=100-%GSA/%CT×100(%).Results:The%GSA(17.9±16.7%)was significantly lower than the%CT(21.5±17.6%)(P<0.036).In all except 2 patients,the%GSA was lower than the%CT.The discrepancy ratio ranged from-4%to 75%(median,20.7%).Conclusion:3D-99mTc-GSA scintigraphy/vascular fused images constructed using SYNAPSE VINCENT were useful for noninvasively performing functional liver volumetry in patients scheduled to undergo various patterns of hepatectomy.In planned resection regions without tumor,the functional volume ratio was about 20%lower than the conventional volume ratio.