Endorectal elastography in the evaluation of rectal tumours

Abstract

Real-time elastography visualizes tissue compliance using an ultrasound platform. Elastography has been used, particularly in the breast, to characterize indeterminate lesions on B-mode imaging as either benign or malignant. The primary aim of this study was to assess the feasibility of routine endorectal elastography to evaluate rectal neoplasia. The secondary aim was to correlate elastography data with histopathological end-points. Sixty-nine patients referred to the outpatient clinic of the Department of Colorectal Surgery at Haukeland University Hospital for the evaluation of rectal tumours were included in this prospective cohort study. All patients underwent digital rectal examination, rigid rectoscopy with biopsy, endorectal ultrasonography and endorectal elastography. In each case a strain ratio was calculated, comparing the tumour tissue with adjacent reference tissue that appeared normal on ultrasound scanning. Histopathologically there were 23 adenomas and 45 adenocarcinomas. One patient died before surgical treatment. Adequate elastography images were obtained in 66/69 (96%) patients. Optimal discrimination of malignant and benign lesions was obtained using a strain ratio cut-off value of 1.25 (sensitivity, 0.93; specificity, 0.96; and accuracy, 0.94). Endorectal elastography can be performed as an integral part of the clinical evaluation of rectal tumours and has good patient compliance. The method is a promising modality for the discrimination between adenocarcinoma and adenoma of the rectum.