Comparison of Blind Transrectal Ultrasonography with Endoscopic Transrectal Ultrasonography in Assessing Rectal and Perirectal Diseases

Abstract

Blind transrectal ultrasonography (BUS) and endoscopic transrectal ultrasonography (EUS) were performed in 10 patients with rectal cancer, in 5 with rectal adenomas, and in 5 with benign perirectal disease. BUS and EUS were equally accurate in staging advanced rectal cancer. EUS was more accurate than BUS in assessing small tumors localized in the mucosa and/or submucosa. Adjacent lymph node abnormality was more clearly visualized with EUS because of the high resolution of this instrument, using a 7.5-MHz ultrasonic beam. In contrast, distant lymph node involvement was more readily seen with BUS because of the penetration depth of this 5-MHz beam. Differentiating rectal adenoma from rectal adenoma with malignancy was easier with EUS than with BUS. Perirectal disease was more accurately visualized with BUS than with EUS. Further studies in a larger number of patients are necessary to document fully the accuracy and limitations of both new diagnostic modalities.

Key Words:

• Blind transrectal ultrasonography (BUS)
• endoscopic transrectal ultrasonography (EUS)
• rectal and perirectal diseases