RESUMO
OBJECTIVE: The objective of this study was to analyze the relationship between quantitative parameters of spectral CT and the Ki67 expression index of tumor cells in hepatocellular carcinoma (HCC). METHODS: A total of 19 patients who underwent preoperative spectral CT dual-phase enhancement and who were diagnosed with HCC by postoperative pathology were prospectively selected. Patients with ≥10% Ki67-positive tumor cells formed a high-Ki67 group, and those with <10% Ki67- positive cells formed a low-Ki67 group. The iodine concentrations (ICs) of the lesion and the descending aorta were measured during the arterial and venous phases. Relative iodine concentration (RIC) was calculated thus: RIC=IClesion/ICdescending aorta. CT values of the lesions at 40 and 70 keV were measured during the enhanced arterial and venous phases. The slope of the spectral curve (λ) was calculated thus: λ = (40 keV-70 keV) /(70-30). To compare the differences in quantitative parameters between the high- and low-Ki67 groups, either an independent samples t-test (normal distribution) or a Mann-Whitney U test (non-normal distribution) was used. Receiver operating characteristic curves were used to evaluate the effectiveness of spectral CT parameters in distinguishing between high-Ki67 and low-Ki67 groups. Pearson correlation analysis was used to evaluate the correlation between spectral CT quantitative parameters and Ki67 expression. RESULTS: IC, RIC and λ values for the high-Ki67 group in arterial and venous phases were higher than those for the low-Ki67 group, P < 0.05. IC, RIC, and λ values in the arterial phase were 0.83, 0.89, and 0.75, respectively; in the venous phase, the values of these three parameters were 0.76, 0.77, and 0.69, respectively. IC, RIC, and λ were positively correlated with Ki67 expression in both arterial and venous phases, with a highest correlation of 0.82 for arterial-phase RIC. CONCLUSION: The quantitative parameters of spectral CT in HCC were correlated with Ki67 expression. This finding may make it easier for clinicians to determine whether a tumor is high or low in Ki67 before surgery.