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PET molecular imaging technique combined with CT colonography may help diagnose polyps and cancer in the colon. The imaging method does not include sedation or bowel preparation.

CT colonography (CTC) is an imaging technique that presents a promising, less invasive alternative to colonoscopy. The CTC scan provides images of the lining of the bowel, which has been gently distended with gas, without the need for sedatives. One potentially major advantage of CTC over colonoscopy is its ability to visualize the large bowel—without the patient having to take strong laxatives. PET scanning produces images of the uptake of blood sugar (glucose) by body tissues. Because cancerous cells tend to take up more blood sugar than normal tissue, these concentrations provide clear evidence of any abnormalities.

 

This study researched the effectiveness of using a combination of CTC and PET scans without any bowel preparation to detect significant abnormalities in the colon. Although other work has demonstrated that combined PET CTC is technically feasible, most have required patients to undergo complete bowel preparation and only a small number of patients have been studied. The current study is the largest to date investigating combined PET CTC in patients without any bowel preparation.

56 patients agreed to undergo a one-hour CTC and PET scan about two weeks before their scheduled colonoscopy. This was done without the use of laxatives. Patients were also asked to complete a questionnaire to see how they tolerated the tests and which ones they preferred.The colonoscopy results were then compared with the CTC scan on its own and with the CTC and PET scans combined. The study found that the combined PET CTC scans detected all the important larger polyps found by the invasive colonoscopy technique. In addition, most patients found the combined scan technique more comfortable and preferred it to colonoscopy.

"The work has shown that combined PET CTC is technically feasible, well tolerated by patients and capable of achieving high diagnostic accuracy," said Stuart A. Taylor, M.D., University College London,and lead researcher of the study."This test would be mainly used in patients less able to tolerate invasive investigations or the preparation required if physicians want to exclude any major pathology in the colon and abdomen."

Source:The Journal of Nuclear Medicine