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 compute d tomography (CT) pneumocolon in the detection of colorectal neoplasms. Methods-A total of 201 consecutive patients with colorectal symptoms or req uiring surveillance for colorectal neoplasms underwent both conventional co lonoscopy 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 grea ter 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 positi ve cancers, but only 20 polyps (seven were greater than or equal to1 cm). T his resulted in a sensitivity of 100% (95% confidence interval (CI) 87-100% ) and specificity of 99% (95% CI 97-100%) for detection of invasive carcino ma, 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 t o1 cm polyps. CT pneumocolon also identified invasive carcinoma not seen at colonoscopy because of incomplete examination in three patients, and detec ted metastases in six colorectal carcinoma patients and extracolonic carcin oma in a further seven patients. Conclusions-CT pneumocolon had a high sensitivity and specificity for detec tion of invasive colorectal carcinoma but not colorectal polyps. CT pneumoc olon may be suitable for initial investigation of patients with symptoms of colorectal malignancy.