Endorectal color Doppler imaging of primary and recurrent rectal wall tumors: preliminary experience

The purpose of our study was to assess whether color Doppler imaging is a useful adjunct to endorectal sonography in evaluating rectal wall neoplasms and in distinguishing recurrent or residual tumor from postoperative changes.

Thirty-two patients underwent endorectal sonography with color Doppler imaging for one of two indications: evaluation and staging of a suspected primary rectal wall cancer, or distinguishing tumor recurrence from postoperative scarring in patients with previously resected lesions. Rectal wall lesions were evaluated for hypervascularity, and their corresponding flow patterns were graded from 0 to 4. Local tumor staging with endorectal sonography and color Doppler imaging was performed before the results of pathological staging were available.

Ninety-five percent of patients with malignant rectal wall tumors demonstrated hypervascularity during color Doppler imaging. In 61% of patients with rectal cancers, prominent perirectal vessels were identified supplying the tumor and were never identified in patients with benign lesions. Endorectal sonography alone correctly identified perirectal fat invasion with a 100% sensitivity and an 83% specificity. Color Doppler imaging during endorectal sonography correctly identified perirectal fat invasion with a sensitivity of 91% and a specificity of 83%. Of the 8 patients with previously resected lesions (five adenomas and three cancers), two patients had recurrent tumor, and both of these demonstrated grade 3 abnormality. Six patients with biopsy-proven fibrosis only had grades of 0 or 1.

Both benign and malignant rectal wall tumors demonstrate abnormal intratumoral hypervascularity when seen with color Doppler imaging. Advanced rectal cancers (T3 or greater) are also associated with abnormal perirectal vascularity. Color Doppler imaging during endorectal sonography does not appear to improve discrimination of benign from T2 (or less) rectal wall cancers, nor does it appear to improve the ability to locally stage rectal wall cancers during endorectal sonography. However, endorectal sonography with color Doppler imaging may add significant information in distinguishing recurrent tumor from postsurgical scarring.