[Correlation analysis of dynamic enhanced energy spectrum CT parameters with Ki-67 high expression in hepatocellular...

Objective: To investigate the correlation between dynamic enhanced energy spectral CT parameters and Ki-67 high expression in hepatocellular carcinoma (HCC). Methods: A cross-sectional study. This retrospective case-control study analyzed the clinical data of 101 patients with pathologically confirmed HCC in Xiamen Hospital of Traditional Chinese Medicine and Zhongshan Hospital of Xiamen University from December 2017 to March 2023. These 101 patients included 84 males and 17 females, and the age[M(Q₁, Q₃)] was 59.0(49.0,66.0)years. These patients were divided into two groups according to the immunohistochemical Ki-67 expression levels in tumor tissues: the high expression group (Ki-67%>20%, n=59) and the low expression group (Ki-67%≤20%, n=42).CT values on 70 keV and 140 keV monochromatic energy images (HU_{70 keV-a}, HU_{140 keV-a}, HU_{70 keV-p}, HU_{140 keV-p}) and water density (D_water-a, D_water-p) were measured in arterial phase and portal vein phase, and the difference of HU_{70 keV}, HU_{140 keV}, D_water values between portal vein and arterial phase (ΔHU_{70 keV}, ΔHU_{140 keV}, ΔD_water), as well as ratio of HU_{70 keV}, HU_{140 keV}, D_watervalues between portal vein and arterial phase (HU_{70 keV}ratio, HU_{140 keV}ratio, D_waterratio) were calculated. Spearman correlation analysis was used to analyze the correlation between the CT spectral parameters and Ki-67%. Multivariate logistic regression model was used to determine the factors associated with high expression of Ki-67. The receiver operating characteristics (ROC) curves were used to indicate the efficacy of dynamic enhanced spectral CT in evaluating Ki-67 high expression in HCC. Results: The high Ki-67 expression group revealed higher alpha fetal protein levels, larger tumor diameter and more irregular tumor shape compared with the low Ki-67 expression group,and the differences were statistically significant (all P<0.05). Spearman correlation analysis showed that the HU_{140 keV-p}, D_water-p, HU_{70 keV} ratio, HU_{140 keV} ratio, D_water ratio, ΔHU_{70 keV}, ΔHU_{140 keV}, ΔD_water were positively correlated with Ki-67 positivity rate (r:0.31-0.50, all P<0.05). The spectral CT parameters (HU_{70 keV-p}, HU_{140 keV-p}, D_water-p, HU_{70 keV} ratio, HU_{140 keV} ratio, D_water ratio, ΔHU_{70 keV}, ΔHU_{140 keV}, ΔD_water) in high Ki-67 expression group were significantly higher than those in low Ki-67 expression group (all P<0.05). Multivariate logistic regression model shows that D_water-p(OR=1.16, 95%CI: 1.05-1.29, P=0.005), ΔHU_{140 keV}(OR=1.39, 95%CI: 1.20-1.62, P<0.001) and irregular tumor morphology (OR=5.25, 95%CI: 1.61-17.12, P=0.006) were correlative factors for high Ki-67 expression. The HU_{140 keV} ratio and ΔHU_{140 keV} alone evaluated the highest AUC of high Ki-67 high expression in HCC, which were 0.82 (95%CI: 0.74-0.90), the sensitivity were 61.0%, and the specificity were 88.1% and 85.7%. The combined analysis of D_water-p, ΔHU_{140 keV} and irregular tumor morphology had an increased AUC of 0.88 (95%CI: 0.81-0.95) in assessment high Ki-67 expression, with the sensitivity of 84.7% and the specificity of 78.6%. Conclusions: Dynamic enhanced spectral CT parameters were positively correlated with the Ki-67 expression in HCC. Spectral CT provides a non-invasive method to evaluate the proliferation status of HCC cells, and the efficiency could be improved by multi-parameter analysis combining spectral CT parameters and morphologic features.