Measurement of the Tumor-to-Normal Ratio for Radioembolization of Hepatocellular Carcinoma: A Prospective Study Comparing 2-Dimensional Perfusion Angiography, Technetium-99m Macroaggregated Albumin, and Yttrium-90 SPECT/CT.

PURPOSE: To calculate the preradioembolic tumor-to-normal (T:N) ratio in hepatocellular carcinoma (HCC) using 2-dimensional (2D) perfusion angiography and compare it with that calculated using technetium-99m macroaggregated albumin (99mTc MAA) single-photon emission computed tomography (SPECT)/computed tomography (CT). MATERIALS AND METHODS: This prospective single-arm study enrolled 15 participants with HCC who underwent 2D perfusion angiography immediately before the enrollment and with the microcatheter located at the same location as 99mTc MAA injection, after which SPECT/CT was performed. Quantitative digital subtraction angiography was used to calculate the area under the curve for the tumor and normal hepatic parenchyma and subsequently calculate the T:N ratio. The T:N ratio was calculated from the 99mTc MAA SPECT/CT and post-yttrium-90 bremsstrahlung SPECT/CT using dosimetry software. RESULTS: The mean participant age was 64.1 years ± 9.8, and the study included 14 (93%) men and 1 (7%) woman. The mean tumor size was 4.1 cm (SD ± 2.4), and all participants received segmental treatments with glass microspheres. The mean T:N ratio calculated by 99mTc MAA SPECT/CT was 2.28 (SD ± 0.89) vs 2.25 (SD ± 0.99) calculated by 2D perfusion angiography (P = .45). For the 13 participants who underwent selective internal radiation therapy (transarterial radioembolization), there was no significant difference between the T:N ratios calculated by 2D perfusion angiography and post-90Y SPECT/CT (2.25 [SD ± 1.05] vs 1.91 [SD ± 0.39]; P = .12). CONCLUSIONS: The T:N ratio calculated by 2D perfusion angiography correlated well with that calculated by 99mTc MAA SPECT/CT.