A prospective single centre study comparing computed tomography pneumocolon against colonoscopy in the detection of colorectal neoplasms

Background and aims-To determine the sensitivity and specificity of computed tomography (CT) pneumocolon in the detection of colorectal neoplasms. Methods-A total of 201 consecutive patients with colorectal symptoms or requiring surveillance for colorectal neoplasms underwent both conventional colonoscopy and CT pneumocolon. Results-On conventional colonoscopy 13 invasive colorectal carcinomas were detected in 13 patients, and 118 polyps in 63 patients (14 polyps were greater than or equal to1 cm in diameter, 25 were 6-9 mm, and 79 were less than or equal to5 mm). CT pneumocolon detected all 13 cancers, two false positive cancers, but only 20 polyps (seven were greater than or equal to1 cm). This resulted in a sensitivity of 100% (95% confidence interval (CI) 87-100%) and specificity of 99% (95% CI 97-100%) for detection of invasive carcinoma, and a sensitivity of 73% (95% CI 56-90%) and specificity of 94% (95% CI 91-98%) for detection of invasive carcinoma and/or greater than or equal to1 cm polyps. CT pneumocolon also identified invasive carcinoma not seen at colonoscopy because of incomplete examination in three patients, and detected metastases in six colorectal carcinoma patients and extracolonic carcinoma in a further seven patients. Conclusions-CT pneumocolon had a high sensitivity and specificity for detection of invasive colorectal carcinoma but not colorectal polyps. CT pneumocolon may be suitable for initial investigation of patients with symptoms of colorectal malignancy.