Abstract and Introduction
Abstract
Objective: Our purpose was to assess the performance of CT colonography (CTC) in patients older than 60 years who were referred because colonoscopy was contraindicated or incomplete.
Materials and Methods: Over a 2-year period, 61 patients underwent CTC at our institution, 42 of whom (26 women, 16 men) were 60 years old or older (range, 60-87 years; mean age, 71 years). After 24-48 hours of ingesting only clear liquids and after colonic cleansing, fecal tagging, and automated CO2 insufflation, patients were scanned using a 16-MDCT scanner. Images were obtained with the patient in the supine and prone positions and as needed in the right or left decubitus position. Axial 2D and 3D endoluminal views were evaluated on a dedicated workstation.
Results: Contraindications to colonoscopy in 12 (29%) of the 42 patients were as follows: anticoagulation (n = 8), increased anesthesia risk (n = 3), and poor tolerance for colonoscopy preparation (n = 1). Incomplete colonoscopy in the other 30 patients (71%) was due to diverticular disease (n = 10), colonic redundancy (n = 10), adhesions (n = 3), residual colonic content (n = 3), sigmoid stricture (n = 1), ventral hernia (n = 1), and unknown cause (n =2). No complications were observed. Optimal distention of the entire colon was achieved in 38 patients (90%). Thirty-nine (93%) of the 42 patients had abnormal findings: diverticular disease (n = 25), one or more polyps (n = 22), a mass lesion (n = 1), a lipoma (n = 1), and inflammatory stricture (n = 1). Extracolonic findings potentially requiring further evaluation or treatment were observed in 26 patients (62%).
Conclusion: CTC using CO2 insufflation was well tolerated and successful in imaging the entire colon in most of the 42 patients, despite the presence of sigmoid diverticular disease or colonic redundancy.
Introduction
Colorectal cancer is the third most common malignancy worldwide. It is the second most common cause of all cancer deaths in the United States. Currently, large numbers of patients for whom screening is recommended do not undergo colonic evaluations. Given these facts, the need for improved screening and diagnostic techniques with greater patient acceptability is evident.
Optical colonoscopy is the standard method for evaluating the colon. This technique allows evaluation of the entire colon in most patients. Also, biopsy of suspicious lesions and polypectomy may be performed during colonoscopy. However, colonoscopy is invasive, requires patient sedation, and is not accepted by all patients. Even when performed by experienced endoscopists, approximately 6-26% of colonoscopic examinations are incomplete and fail to reach the level of the cecum. The reasons for incomplete colonoscopy are redundant or tortuous colon, marked diverticular disease, obstructing masses and strictures, angulation or fixation of colonic loops, adhesions due to prior surgery, spasm, or poor colonic preparation. Colonoscopy requires intensive bowel preparation that many patients find to be the most difficult part of the test and that some cannot tolerate. In patients with medical conditions that result in increased sedation risk (e.g., cardiovascular or pulmonary disease) or in those being treated with anticoagulants, a less invasive technique for evaluation of the colon might be preferred to minimize the risk for possible complications.
The number of incomplete colonoscopies and contraindications tends to increase in elderly patients. In elderly patients, the rate of incomplete colonoscopies has been reported to be as high as 22-33%. When colonoscopy cannot be performed or the examination is incomplete, alternative techniques, such as colonoscopy with thinner colonoscopes or gastroscopes, barium enema, CT colonography (CTC), and MR colonography, may be preferred.
CTC is a noninvasive imaging technique that has the advantages of rapid data acquisition, minimal patient discomfort, no need for sedation, and virtually no recovery time. Although the subject of controversy, there is evidence that the sensitivity of CTC compares favorably with that of optical colonoscopy in the detection of colorectal neoplasia. During a routine study, in addition to imaging the entire colon, unenhanced CT of the abdomen and pelvis is also performed. In some patients, this may help to reveal additional significant extracolonic findings.
The purpose of our study was to assess the performance of CTC in older patients who were referred because colonoscopy either could not be performed due to contraindications or had been performed but was incomplete.