ABSTRACT
Objective To evaluate the value of real-time ultrasonic elastography in the differential diagnosis of rectal tumors.Methods One hundred patients (30 cases of adenoma and 70 cases of adenocarcinoma) with rectal tumors proved by pathology and 70 normal subjects referred to the First Affiliated Hospital of China Medical University from April 2012 to October 2013 were included in this prospective cohort. All patients underwent real-time ultrasonic elastography. The tumour tissue and reference tissue were chosen for strain ratio measurements. Only tumor tissue was selected for the tumor sample area. Tissue recognized as normal rectal wall and perirectal tissue was selected as the reference sample area. At the same time the elasticity score were calculated. Receiver operating characteristic (ROC) curves of the elasticity score and strain ratio method were used to find the cut-off point of adenoma and adenocarcinoma. The corresponding sensitivity, accuracy and specifi city were calculated. One-way ANOVA was used to comparestrain ratio value among healthy control group, retal adenoma group and rectal adenocarcinoma group and among patients with different preoperative stages of adenocarcinoma group. LSD-t test was used to compare strain ratio value between two groups.Results ROC curve showed that the best cut-off value of elasticity score in diagnosis of rectal tumor was 3, the sensitivity, specificity and accuracy were 85.1%, 73.1% and 82.0%, and the area under ROC curve was 0.780. The best cut-off value of strain ratio in diagnosis of rectal tumour was 2.34, the sensitivity, specifi city and accuracy in diagnosis were 91.4%, 83.3% and 89.0%, and the area under ROC curve was 0.945. Strain ratio of healthy control group, rectal adenoma group and rectal adenocarcinoma group was 0.74±0.44, 1.75±0.58 and 7.48±6.80. There was signifi cantly statistical difference among three groups in strain ratio. Compared with the strain ratio of healthy control group and rectal adenoma group, that of rectal adenocarcinoma group was higher (t=-8.26, P=0.000; t=-6.98,P=0.000). Compared with the strain ratio of healthy control group, that of rectal adenoma group was higher (t=-8.53,P=0.000). Strain ratio of patients with preoperative pathological stages T1, T2, T3 and T4 rectal carcinoma was 4.91±3.60, 7.07±7.23, 8.64±2.62 and 8.58±9.95 and there was no significantly statistical difference among patients with different preoperative stages of adenocarcinoma group (F=0.86,P=0.47).Conclusion The real-time ultrasonic elastography is a promising modalityfor the differential diagnosis of rectal tumors.