Diagnostic and prognostic value of 99mTc-MAA SPECT/CT for treatment planning of 90Y-resin microsphere radioembolization for hepatocellular carcinoma: comparison with planar image.

99mTc-macroaggregated albumin (MAA) imaging is performed before transarterial radioembolization (TARE), in which SPECT/CT is presumed more precise than planar image. However, additive role of SPECT/CT has not been well established. Thirty-four consecutive hepatocellular carcinoma patients of intermediate and advanced stages who underwent 90Y-microsphere TARE were recruited. On pre-treatment planning scan using 99mTc-MAA, image characteristics and absorbed dose for target tumors calculated by partition model methods were estimated on planar image and SPECT/CT, respectively. The measurements were repeated on post-treatment 90Y PET/CT, as the reference standard. Treatment response was assessed and predictive values of image parameters were analyzed. The image characteristics including heterogeneity, necrosis and thrombosis uptake were better delineated on SPECT/CT than planar scan. The agreement and correlation of TNr between SPECT/CT and PET/CT were stronger than those between planar scan and PET/CT. Tumor dose estimated on 99mTc-MAA SPECT/CT was more effective than planar image for prediction of treatment response, with cutoff value 125 Gy (sensitivity of 86% and specificity of 75%). In conclusion, 99mTc-MAA SPECT/CT is more closely correlated with post-treatment 90Y PET/CT, and is more effective for predicting treatment response than planar scan. SPECT/CT is superior to planar image in simulation before 90Y TARE.