Accuracy of CT-Colonography Measurements: Implication Upon Synchronous Lesion Localization and Incomplete Colonoscopy Predictive Factors
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- Category: Vol. 81, September 2013
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Accuracy of CT-Colonography Measurements: Implication Upon Synchronous Lesion Localization and Incomplete Colonoscopy Predictive Factors, MOHAMED Sh. EL-SHARKAWY
Abstract
Background: CT-Colonography (CTC) is a valuable mo-dality for complete colonic assement particularly in detecting synchronous lesions in incomplete colonoscopy with stenotic colorectal cancer. A considerable percentage of incomplete colonoscopy is due to looping, elongation and tortuosity. Other reasons included stenotic colonic lesions and advanced diverticular disease. Colon anatomy particularly colon length, number of colonic folds and flexures have an impact on technical problems in conventional colonoscopy and also on outcome of operative management of colorectal cancer. Not much is known about colonic anatomy, tortuosity and length as well as the incidence of looping in such cases. Although barium enema has been used previously to estimate colonic length, CT-Colonography (CTC) represents a much more precise tool for assessing anatomy and length of this complex three-dimensional (3D) structure. Also Distance measurements on CTC has an important impact on lesion localization, planning of surgical treatment of colorectal cancer and also prospective distances documentation is essential for colonos-copist particularly for future procedures like polypectomy, in colonoscopy.
Aim of the Study: The first goal is to assess accuracy of CTC measurements compared to colonoscopy and post-surgical specimen's measurements. The second goal is to apply CTC measurements in assessment of total colonic length and number of folds as a known predictive anatomical factor for incomplete colonoscopy.
Patients and Methods: 97 consecutive patients were examined by CTC in our institution in the period of January 2010 till February 2013. Of these patients 36 consecutive patients were diagnosed as stenotic colorectal cancer referred for CTC after incomplete colonoscopy and later treated by partial or total colectomy. They are assessed by CTC using 3D colon maps and 2D images. All 36 patients are evaluated for distance of the stenotic lesion from the anus, lesions length and presence of synchronous lesions in CTC, colonoscopy and post-colectomy surgical specimen measurements. After that the overall colon length, number of colonic folds <900° are measured. Results: CTC measurements of distance of stenotic lesions from the anus and lesion length are well correlated to post-surgical pathology specimen and colonoscopy. It showed 100% sensitivity and 96.9% in detection of synchronous lesions. Mean colonic length (cm) in our patients was 151.39±19.75. Numbers of colonic folds were 6 folds in 11.1%, 7 folds in 36.1%, 8 in 36.1%, 9 in 13.9% and 10 in 2.8% with Mean±SD = 6.61±0.96.
Conclusion: CTC accurately assesses tumor location and size with high sensitivity and specificity in synchronous lesions detection. Predictive anatomical factors for potentially difficult endoscopic colonoscopy can be defined by CT Colonography namely Colon length measurements', extrafold-ing and lesion localization are accurately assessed and mea-sured by CTC.