Noninvasive prediction of Ki-67 expression in pancreatic cancer via contrast-enhanced ultrasound quantitative parameters: A diagnostic model study

BACKGROUND The expression level of Ki-67 and the degree of differentiation in pancreatic cancer determine tumor aggressiveness and patient prognosis, which holds significant implications for clinical decision-making. A major challenge in preoperative pancreatic ductal adenocarcinoma management is predicting tumor malignancy. Contrast-enhanced ultrasound (CEUS), a dynamic imaging technique based on blood pool visualization, can reveal lesion vasculature and provide quantitative perfusion data reflecting angiogenesis. By tracking contrast agent kinetics, CEUS offers non-invasive insights into tumor vascularization, helping assess malignancy potential. AIM To investigate the correlation between Ki-67 and pancreatic cancer differentiation using CEUS quantitative parameters and evaluated their diagnostic accuracy. METHODS This retrospective study analyzed pancreatic cancer patients who underwent CEUS and pathological confirmation. Pathological differentiation, clinical data, and quantitative CEUS parameters [maximum intensity (IMAX), rise time (RT), rise slope 50% (Rs50), rise slope 10%-90% (Rs1090), etc.] were collected. Based on Ki-67 expression (< 50% vs >= 50%), patients were divided into low- and high-expression groups. The study evaluated correlations between Ki-67 expression, differentiation degree, and CEUS quantitative parameters to assess tumor aggressiveness. RESULTS Among 54 patients (25 high Ki-67, 29 low Ki-67), significant differences (P < 0.05) were observed in Rs50, IMAX, wash-out area under the curve (WoutAUC), wash-in and out area under curve, and Rs1090 between high and low Ki-67 groups. High-expression patients showed elevated Rs50, IMAX, WoutAUC, and area under the curve (AUC), while RT and falling slope 50% (Fs50) were lower. Rs1090 demonstrated the highest diagnostic accuracy (AUC = 0.863, sensitivity = 0.92, specificity = 0.759). Fs50 was effective in low Ki-67 detection (AUC = 0.838). No correlation was found between enhancement patterns and Ki-67 or differentiation. CONCLUSION CEUS parameters (Rs50, IMAX, WoutAUC, Rs1090) strongly correlate with Ki-67, aiding non-invasive pancreatic cancer assessment. Rs1090/IMAX predict high Ki-67; Fs50 identifies low Ki-67, supporting CEUS for tumor aggressiveness evaluation.