Teresa Gallo

Diagnostic accuracy of computed tomographic colonography for the detection of advanced neoplasia in individuals at increased risk of colorectal cancer

CONTEXT Computed tomographic (CT) colonography has been recognized as an alternative for colorectal cancer (CRC) screening in average-risk individuals, but less information is available on its performance in individuals at increased risk of CRC. OBJECTIVE To assess the accuracy of CT colonography in detecting advanced colorectal neoplasia in asymptomatic individuals at increased risk of CRC using unblinded colonoscopy as the reference standard. DESIGN, SETTING, AND PARTICIPANTS This was a multicenter, cross-sectional study. Individuals at increased risk of CRC due to either family history of advanced neoplasia in first-degree relatives, personal history of colorectal adenomas, or positive results from fecal occult blood tests (FOBTs) were recruited in 11 Italian centers and 1 Belgian center between December 2004 and May 2007. Each participant underwent CT colonography followed by colonoscopy on the same day. MAIN OUTCOME MEASURES Sensitivity and specificity of CT colonography in detecting individuals with advanced neoplasia (ie, advanced adenoma or CRC) 6 mm or larger. RESULTS Of 1103 participants, 937 were included in the final analysis: 373 cases in the family-history group, 343 in the group with personal history of adenomas, and 221 in the FOBT-positive group. Overall, CT colonography identified 151 of 177 participants with advanced neoplasia 6 mm or larger (sensitivity, 85.3%; 95% confidence interval [CI], 79.0%-90.0%) and correctly classified results as negative for 667 of 760 participants without such lesions (specificity, 87.8%; 95% CI, 85.2%-90.0%). The positive and negative predictive values were 61.9% (95% CI, 55.4%-68.0%) and 96.3% (95% CI, 94.6%-97.5%), respectively; after group stratification, a significantly lower negative predictive value was found for the FOBT-positive group (84.9%; 95% CI, 76.2%-91.3%; P < .001). CONCLUSIONS In a group of persons at increased risk for CRC, CT colonography compared with colonoscopy resulted in a negative predictive value of 96.3% overall. When limited to FOBT-positive persons, the negative predictive value was 84.9%.

An automatic method for colon segmentation in CT colonography

An automatic method for the segmentation of the colonic wall is proposed for abdominal computed tomography (CT) of the cleansed and air-inflated colon. This multistage approach uses an adaptive 3D region-growing algorithm, with a self-adjusting growing condition depending on local variations of the intensity at the air-tissue boundary. The method was evaluated using retrospectively collected CT scans based on visual segmentation of the colon by expert radiologists. This evaluation showed that the procedure identifies 97% of the colon segments, representing 99.8% of the colon surface, and accurately replicates the anatomical profile of the colonic wall. The parameter settings and performance of the method are relatively independent of the scanner and acquisition conditions. The method is intended for application to the computer-aided detection of polyps in CT colonography.

Comparing CT colonography and flexible sigmoidoscopy: a randomised trial within a population-based screening programme

Importance and aims The role of CT colonography (CTC) as a colorectal cancer (CRC) screening test is uncertain. The aim of our trial was to compare participation and detection rate (DR) with sigmoidoscopy (flexible sigmoidoscopy (FS)) and CTC in a screening setting. Design setting and participants We conducted two randomised clinical trials (RCTs). (1) Participation RCT: individuals, aged 58 years, living in Turin (Italy), were randomly assigned to be invited to FS or CTC screening; (2) detection RCT: residents in northern Italy, aged 58–60, giving their consent to recruitment, were randomly allocated to CTC or FS. Polyps ≥6 mm at CTC, or ‘high-risk’ distal lesions at FS, were referred for colonoscopy (TC). Main outcome measures Participation rate (proportion of invitees examined); DR of advanced adenomas or CRC (advanced neoplasia (AN)). Results Participation was 30.4% (298/980) for CTC and 27.4% (267/976) for FS (relative risk (RR) 1.1; 95% CI 0.98 to 1.29). Among men, participation was higher with CTC than with FS (34.1% vs 26.5%, p=0.011). In the detection RCT, 2673 subjects had FS and 2595 had CTC: the AN DR was 4.8% (127/2673, including 9 CRCs) with FS and 5.1% (133/2595, including 10 CRCs) with CTC (RR 1.08; 95% CI 0.85 to 1.37). Distal AN DR was 3.9% (109/2673) with FS and 2.9% (76/2595) with CTC (RR 0.72; 95% CI 0.54 to 0.96); proximal AN DR was 1.2% (34/2595) for FS vs 2.7% (69/2595) for CTC (RR 2.06; 95% CI 1.37 to 3.10). Conclusions and relevance Participation and DR for FS and CTC were comparable. AN DR was twice as high in the proximal colon and lower in the distal colon with CTC than with FS. Men were more likely to participate in CTC screening. Trial registration number NCT01739608; Pre-results.

Computed tomography colonography in routine clinical practice

Objective To describe the experience of a radiology unit in using open access computed tomography (CT) colonography instead of double-contrast barium enema in patients who refused or had an incomplete first-attempt colonoscopy. Methods All consecutive patients who underwent CT colonography from December 1998 to August 2001 were recalled and evaluated. Patients in whom CT colonography showed intraluminal growths were sent for colonoscopy, performed using deep sedation if the first attempt failed. Results A total of 463 consecutive CT colonography examinations were performed: 304 patients were re-traceable and were evaluated. In 85 cases CT colonography reported the presence of intraluminal growth. Colonoscopy confirmed the presence of 74 of the 94 polyps, and of 43 of the 48 cancers found at CT colonography. Colonoscopy also diagnosed an additional two cancers in two patients with CT colonography findings of inflammatory changes, and an additional 26 polyps in 16 patients. On a per-lesion basis, the positive predictive value of CT colonography was 73%, 80% and 87% for polyps ⩽ 5 mm, 6–9 mm and ⩾ 10 mm, respectively, and was 90% for cancer. On a per-patient basis, the positive predictive value was 60%, 72% and 89% for lesions ⩽ 5 mm, 6–9 mm and ⩾ 10 mm, respectively, and was 93% for cancer. Conclusion CT colonography on an open access basis can be confidently used as a routine test instead of double-contrast barium enema when total colonoscopy cannot be performed.

Bile Duct and Gallbladder Tumors

Bile duct carcinoma is a rare condition, accounting for less than 2% of all tumors, but its prognosis, despite multimodal treatments, remains dismal. Radical resection with a microscopically negative margin is the only curative therapy. Thus, identifying precisely the anatomical tumor site and extension is mandatory for a correct surgical planning. Surgical strategy is largely conditioned by the ways of tumor spread. The extension of the bile duct carcinoma is classified into two types: vertical spread to adjacent tissues, such as liver parenchyma, portal venous system, the hepatic artery, and lymph nodes and horizontal spread along the axis of the bile ducts.

CT and MR Colonography

CT or MR colonography, first described as virtual colonoscopy by Vining in 1994, is a non-invasive imaging method that uses CT or MR data sets combined with specialised imaging software to examine the colon. Various names have been given to virtual colonoscopy, including CT pneumocolon and CT or MR colonography. Since 2002, CT colonography (CTC) and MR colonography (MRC) have been definitively included as standard reference terms in medical databases.