Ultrasonography in diagnosing colorectal cancers in patients presenting with abdominal distension.

Abstract

OBJECTIVE: To determine the usefulness of abdominal ultrasonography for diagnosing colorectal cancer in patients presenting with abdominal distension. DESIGN, SETTING AND PARTICIPANTS: A prospective case series of consecutive adult patients with abdominal distension admitted to the National Taiwan University Hospital between January 2001 and July 2004. All participants were examined by abdominal ultrasonography. Those with suspected colorectal tumours on ultrasonography had follow-up colonoscopy, while all other patients had computed tomography scans. MAIN OUTCOME MEASURES: Accuracy of abdominal ultrasonography for diagnosing colorectal cancer in patients with abdominal distension; incidence of colorectal cancer. RESULTS: Of 511 patients eligible for inclusion in our study, 97 (19.0%) were confirmed to have colorectal cancer. For diagnosis of colorectal cancer, ultrasonography had a sensitivity of 92.8% (95% CI, 85.2%-96.8%); a specificity of 98.8% (95% CI, 97.0%-99.6%); a positive predictive value of 94.7% (95% CI, 87.6%-98.0%); a negative predictive value of 98.3% (95% CI 96.4%-99.3%); and an accuracy of 97.7%. CONCLUSION: Ultrasonography is a sensitive tool for diagnosing colorectal cancer in patients presenting with abdominal distension.