Use of virtual endoscopy with computerized tomography in the identification of colorectal neoplasms. Prospective study with symptomatic patients

INTRODUCTION: Aim of this study was to evaluate the sensitivity of virtual colonoscopy (CT colonography) in the identification of colorectal cancer and to define the limitations and the advantages of this imaging modality, as well as indications to the examination. MATERIAL AND METHODS: We examined prospectively 62 symptomatic patients aged 36 to 82 years (28 women and 34 men). All patients underwent both conventional and virtual colonoscopy on the same day; the conventional examination allowed exploration of the entire colon. RESULTS: Conventional colonoscopy identified 89 lesions 3-50 mm in diameter, namely 84 benign and 5 malignant lesions. No lesions were identified in 12 patients. CT colonography identified 52 of the 89 lesions, with 57.1% diagnostic accuracy. There were 11 false positives (82.5% positive predictive value and 52.2% specificity) and 37 false negatives (24.5% negative predictive value and 58.4% sensitivity). Sensitivity was significantly higher (85.7%) for polyps > or = 1 cm. CONCLUSIONS: Virtual colonoscopy is an imaging modality with good diagnostic yield, well tolerated by patients and with great potentials for further development. We suggest that the examination be performed in symptomatic patients who cannot undergo total colonoscopy or refuse the other imaging modalities. Further studies are warranted in larger series of patients, possibly introducing it in screening programs.