The correlation between time-intensity curve parameters of transrectal contrast-enhanced ultrasound and pathological prognostic factors in rectal adenocarcinoma

Aims: To investigate the correlation between time-intensity curve (TIC) parameters obtained from transrectal contrast-enhanced ultrasound (TR-CEUS) and important pathological prognostic factors in rectal adenocarcinoma.Material and methods: We retrospectively included 477 patients with pathologically confirmed rectal adenocarcinoma. TIC parameters were derived from preoperative dynamic TR-CEUS images. These parameters included peak intensity (PI), time to peak (TTP),mean transit time (MTT), slope (S), and area under the curve (AREA). Pathological prognostic factors included TN stage, tumor diameter, lymphovascular invasion (LVI), perineural invasion, and tumor differentiation. Spearman’s correlation analysis and binary logistic regression were used to analyze the association between TIC parameters and pathological prognostic factors.Results: pT1-2 stages rectal carcinomas exhibited higher PI-max, PI-min, S-max, S-min, AREA-max, and AREA-min than pT3-4 stages (all p<0.05). pN0 stage rectal adenocarcinomas displayed higher PI-max, S-max, AREA-max, PI-ratio, Sratio, and AREA-ratio than pN1-2 stage (all p<0.05). PI-ratio and S-ratio were higher in the LVI-negative and tumor diameter ≥4cm group compared to the LVI-positive and tumor diameter <4cm group, respectively (p<0.05). Well-differentiated rectal adenocarcinomas displayed higher PI-max, AREA-max, PI-ratio, S-ratio, and AREA-ratio than the moderate-poor differentiated group (all p<0.05). PI-max, S-max, AREA-max, PI-ratio, S-ratio, and AREA-ratio were negatively correlated with pN stage (all p<0.05). PI-ratio and S-ratio were independent predictive factors for the pN stage (OR=0.774, OR=1.048). S-ratio and AREA-ratio were independent predictive factors for tumor differentiation (OR=1.071, OR=0.911).Conclusions: TIC parameters derived from TR-CEUS exhibit correlations with specific pathological prognostic factors in rectal adenocarcinomas. This non-invasive method may hold promise for preoperatively assessing the prognosis of rectal adenocarcinoma patients.