Comparison of the Uptake of Hepatocellular Carcinoma on Pre-Therapeutic MDCT, CACT, and SPECT/CT, and the Correlation with Post-Therapeutic PET/CT in Patients Undergoing Selective Internal Radiation Therapy

Abstract

(1) Background: To comparatively analyze the uptake of hepatocellular carcinoma (HCC) on pre-therapeutic imaging modalities, the arterial phase multi-detector computed tomography (MDCT), the parenchymal phase C-arm computed tomography (CACT), the Technetium⁹⁹m-macroaggregates of human serum albumin single-photon emission computed tomography/computed tomography (SPECT/CT), and the correlation to the post-therapeutic Yttrium⁹⁰ positron emission tomography/computed tomography (PET/CT) in patients with selective internal radiation therapy (SIRT). (2) Methods: Between September 2013 and December 2016, 104 SIRT procedures were performed at our institution in 74 patients with HCC not suitable for curative surgery or ablation. Twenty-two patients underwent an identical sequence of pre-therapeutic MDCT, CACT, SPECT/CT, and post-therapeutic PET/CT with a standardized diagnostic and therapeutic protocol. In these 22 patients, 25 SIRT procedures were evaluated. The uptake of the HCC was assessed using tumor-background ratio (TBR). Therefore, regions of interest were placed on the tumor and the adjacent liver tissue on MDCT (TBR^MDCT), CACT (TBR^CACT), SPECT/CT (TBR^SPECT/CT), and PET/CT (TBR^PET/CT). Comparisons were made with the Friedman test and the Nemenyi post-hoc test. Correlations were analyzed using Spearman's Rho and the Benjamini-Hochberg method. The level of significance was p < 0.05. (3) Results: TBR on MDCT (1.4 ± 0.3) was significantly smaller than on CACT (1.9 ± 0.6) and both were significantly smaller compared to SPECT/CT (4.6 ± 2.0) (pFriedman-Test < 0.001; pTBR^MDCT/TBR^CACT = 0.012, pTBR^MDCT/TBR^SPECT/CT < 0.001, pTBR^CACT/TBR^SPECT/CT < 0.001). There was no significant correlation of TBR on MDCT with PET/CT (rTBR^MDCT/TBR^PET/CT = 0.116; p = 0.534). In contrast, TBR on CACT correlated to TBR on SPECT/CT (rTBR^CACT/TBR^SPECT/CT = 0.489; p = 0.004) and tended to correlate to TBR on PET/CT (rTBR^CACT/TBR^PET/CT =0.365; p = 0.043). TBR on SPECT/CT correlated to TBR on PET/CT (rTBR^SPECT/CT/TBR^PET/CT = 0.706; p < 0.001) (4) Conclusion: The uptake assessment on CACT was in agreement with SPECT/CT and might be consistent with PET/CT. In contrast, MDCT was not comparable to CACT and SPECT/CT, and had no correlation with PET/CT due to the different application techniques. This emphasizes the value of the CACT, which has the potential to improve the dosimetric assessment of the tumor and liver uptake for SIRT.

Keywords: C-arm computed tomography (CACT); Yttrium90 (Y90); hepatocellular carcinoma (HCC); liver; multi-detector computed tomography (MDCT); positron emission tomography/computed tomography (PET/CT); selective internal radiation therapy (SIRT); single-photon emission computed tomography/computed tomography (SPECT/CT).

Figure 1

Image analysis. A region of interest was drawn on the tumor and three regions of interest were placed on the adjacent liver tissue in equal positions on arterial phase multi-detector tomography (A), parenchymal phase C-arm computed tomography (B), Technetium⁹⁹m-macroaggregates of human serum albumin single-photon emission computed tomography and computed tomography (C), Yttrium⁹⁰ positron emission tomography and computed tomography (D), mean hounsfield units, counts, and becquerel/milliliter were recorded.