Preoperative assessment of Ki-67 expression in hepatocellular carcinoma using a multi-parametric spectral CT approach

Ki-67 is a pivotal biomarker for evaluating the prognosis of hepatocellular carcinoma (HCC). This study aimed to investigate the utility of qualitative and quantitative parameters derived from spectral computed tomography (CT) in assessing Ki-67 expression in HCC.

This prospective, single-center study included 89 patients (94 lesions) with pathologically confirmed HCC from February 2023 to February 2024. Participants underwent enhanced abdominal spectral CT scans within one week prior to surgery. The patients were divided into the following two groups based on the positive rate of Ki-67 (Ki-67%): a high-expression group (Ki-67 >20%, n=42); and a low-expression group (Ki-67 ≤20%, n=52). The spectral parameters assessed included CT values at 40 and 70 keV, iodine concentration (IC), the slope of the spectral Hounsfield unit (HU) curve (λHU), normalized iodine concentration (NIC) during the arterial phase (AP) and portal venous phase (PVP), and extracellular volume (ECV) fraction. Statistical significance of spectral CT parameters related to Ki-67 expression status was compared across different groups, and correlations between spectral CT parameters and Ki-67 expression levels were analyzed.

Significant differences were observed between the low and high Ki-67 expression groups concerning age, alpha-fetoprotein (AFP) levels, and capsule integrity (P=0.002, P=0.013, and P=0.005, respectively). Notable differences were also found in intratumoral NIC-AP, NIC-PVP, AP slope, PVP slope, and ECV fraction (P=0.017, P=0.005, P=0.001, P<0.001, and P=0.001, respectively). Meanwhile, in the comparative analysis between the low and high expression group of Ki-67, there were no statistically significant differences in the peritumoral <1 cm NIC-AP and NIC-PVP, as well as transtumoral NIC-AP and NIC-PVP levels (P>0.05). Ki-67 expression in HCC exhibited negative correlations with intratumoral NIC-AP (r=-0.248; P=0.016), NIC-PVP (r=-0.291; P=0.004), AP slope (r=-0.330; P=0.001), PVP slope (r=-0.367; P<0.001), and ECV fraction (r=-0.339; P=0.001).

Qualitative and quantitative parameters from spectral CT provide valuable information for distinguishing between low and high Ki-67 expression in HCC.