Patients' preferences about follow-up of medium size polyps detected at screening CT colonography.

PURPOSE: To evaluate patients' preferences regarding follow-up of medium size polyps detected at screening CT colonography (CTC). METHODS AND MATERIALS: 193 C-RADS2 asymptomatic patients were asked to fill in a form explaining the indications, technique and potential complications of CTC, and were invited to choose their preferred examination technique (CTC or optical colonoscopy: OC) and their follow-up interval by repeated consultations at 3-month intervals. The follow-up interval for CTC and OC was recorded. RESULTS: 87/193 C-RADS2 patients (45.1%) accepted follow-up. Average time interval for follow-up was comparable between CTC and OC (9.00 ± 4.24 vs. 9.00 ± 4.39 months, respectively; P = 0.7188). No patients chose to undergo a 3-year follow-up with either CTC or OC. Most patients elected to have follow-up with either CTC or OC before 18 months rather than later (P = 0.0004). CONCLUSIONS: A substantial fraction of C-RADS2 patients prefer to undergo immediate OC and polyp removal rather than follow-up, and the majority of those accepting follow-up are willing to wait for less than 18 months. Such findings may suggest a revision of the proposed C-RADS2 category.

Colonic polyps: inheritance, susceptibility, risk evaluation, and diagnostic management.

Colorectal cancer (CRC) is the third-ranked neoplasm in order of incidence and mortality, worldwide, and the second cause of cancer death in industrialized countries. One of the most important environmental risk factors for CRC is a Western-type diet, which is characterized by a low-fiber and high-fat content. Up to 25% of patients with CRC have a family history for CRC, and a fraction of these patients are affected by hereditary syndromes, such as familial adenomatous polyposis, Gardner or Turcot syndromes, or hereditary nonpolyposis colorectal cancer. The onset of CRC is triggered by a well-defined combination of genetic alterations, which form the bases of the adenoma-carcinoma sequence hypothesis and justify the set-up of CRC screening techniques. Several screening and diagnostic tests for CRC are illustrated, including rectosigmoidoscopy, optical colonoscopy (OC), double contrast barium enema (DCBE), and computed tomography colonography (CTC). The strengths and weaknesses of each technique are discussed. Particular attention is paid to CTC, which has evolved from an experimental technique to an accurate and mature diagnostic approach, and gained wide acceptance and clinical validation for CRC screening. This success of CTC is due mainly to its ability to provide cross-sectional analytical images of the entire colon and secondarily detect extracolonic findings, with minimal invasiveness and lower cost than OC, and with greater detail and diagnostic accuracy than DCBE. Moreover, especially with the advent and widespread availability of modern multidetector CT scanners, excellent quality 2D and 3D reconstructions of the large bowel can be obtained routinely with a relatively low radiation dose. Computer-aided detection systems have also been developed to assist radiologists in reading CTC examinations, improving overall diagnostic accuracy and potentially speeding up the clinical workflow of CTC image interpretation.

Post-surgical follow-up of colorectal cancer: role of contrast-enhanced CT colonography.

AIM: To evaluate the role of CT colonography (CTC) in the follow-up of patients having received partial colectomy for colorectal cancer. METHODS AND MATERIALS: CTC was performed in 72 subjects with history of partial colectomy for colorectal cancer. Colectomy had been performed in the right colon (n = 18), descending colon (n = 15), sigmoid colon (n = 21), and rectum (n = 18). Patients underwent CTC following incomplete conventional colonoscopy due to intolerance to endoscope insertion or luminal stenosis. In 70 cases pneumocolon was obtained through a rectal tube, and in 2 cases through a cutaneous anastomosis. CTC datasets were analyzed in combined 2D and 3D mode. All patients in whom CTC was suggestive for or raised the suspicion of disease recurrence underwent colonoscopy in sedation for confirmation of CTC findings. RESULTS: CTC detected 7 cases of anastomotic stenosis. In 6/7 patients the stenosis was located in the sigmoid colon and in 1/7 patients at the level of the ileo-colic junction in the transverse colon. Out of these cases, four were fibrotic and three were neoplastic stenoses. In none of these cases was the CT appearance of the stenoses specific for disease recurrence, and conventional colonoscopy together with biopsy was necessary in order to characterize such findings. However, sensitivity of CTC in detecting anastomotic stenosis was 100% (7/7). One colonic mass (5 cm largest diameter) was detected in one case at the level of the proximal transverse colon in a patient with left colectomy performed 2 years before. The study of the residual colon showed 3 polyps in three patients (8, 6, and 5 mm, respectively). All CT findings were confirmed and characterized by conventional colonoscopy. In all cases the residual colon was entirely visualized by CTC with a completion rate of 100%. CONCLUSIONS: CTC is a feasible and minimally invasive method for full exploration of the colon after surgical resection allowing detection of cancer recurrence, metachronous disease, and distant metastases in one single study, and represents a valid alternative to conventional colonoscopy in this patient population.

CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden.

Our aim is to compare the radiation dose associated with a low-dose CT colonography (CTC) protocol for colorectal cancer screening with that delivered by double-contrast barium enema (DCBE). CTC of twenty asymptomatic individuals (M:F = 10:10) participating to a colorectal cancer screening program and DCBE of fifteen patients (M:F = 6:9) were evaluated. For CTC, absorbed dose was determined by calculating the dose-length product for each CTC examination from measurements on a CT dose phantom equipped with a CT ion chamber. For DCBE, the free-in-air Kerma at the patient's X-ray entry surface and the Kerma-area product during fluoroscopy and fluorography were measured with a Barracuda system, with fluoroscopy times being recorded blinded to the performing operator. Effective dose at CTC was 2.17 ± 0.12 mSv, with good and excellent image quality in 14/20 (70%) and 6/20 cases (30%), respectively. With DCBE, effective patient dose was 4.12 ± 0.17 mSv, 1.9 times greater than CTC (P < 0.0001). Our results show that effective dose from screening CTC is substantially lower than that from DCBE, suggesting that CTC is the radiological imaging technique of the large bowel with the lowest risk of stochastic radiation effects.