Application of CT attenuation correction in ^99mTc-GSA SPECT liver imaging

Objective To investigate the effect of CT attenuation correction on the ^99mTc-GSA SPECT imaging in patients with hepatocellular carcinoma. Methods We selected 24 patients who underwent ^99mTc-GSA SPECT/CT scans in the department of nuclear medicine in the first medical center of Chinese PLA General Hospital from March 2017 to August 2018,and calculated the K and FV values with or without CT attenuation correction.The K and FV values were recorded as GSA-K_NAC and GSA-FV_NAC without CT attenuation correction,and GSA-K_AC and GSA-FV_AC after CT attenuation correction.The difference was compared between these two groups and their correlations with ICG,and liver serum biochemical indicators were explored. Results The values of GSA-K_NAC and GSA-K_AC were 0.21±0.06 and 0.20±0.06 respectively,without significant difference （P=0.750）.GSA-FV_NAC was significantly higher than GSA-FV_AC （10.00±2.8 vs 12.64±3.31,P<0.001）.GSA-K_AC was correlated with INR （r=-0.49）,PLT （r=0.49）,PTA （r=0.62）,PT （r=-0.51）,ICG-R15 （r=-0.66）,ICG-K （r=0.81） （all P<0.05）,and it had the highest correlation with ICG-K.There was no association between GSA-FV_NAC and serum biochemical indicators or ICG （P>0.05）.GSA-FV_AC was correlated with T-BIL and ICG-R15 （r=-0.58 and-0.53,P<0.05,respectively）. Conclusion The values of GSA-K and GSA-FV obtained by CT attenuation correction are accurate and can indicate the liver function via ^99mTc-SPECT and CT fusion imaging.^99mTc-GSA SPECT/CT imaging can facilitate the evaluation of liver function,and it has close correlation with other clinical liver function indicators.