CTC Interpretation by Gastroenterologists

Abstract

As shown by Young et al.(1) in this issue of the Americn Journal of Gastroenterology , adequate diagnostic performance in the interpretation of computed tomographic colonography (CTC) would appear to be achievable for a subset of gastroenterologists with a specifi c interest in colorectal screening. Although it is likely that some gastroenterologists will aspire to interpret CTC in clinical practice, there are a number of issues and circumstances that should fi rst be considered, as they may dampen this enthusiasm somewhat. In the end, quality assurance measures will help ensure adequate performance levels for CTC interpretation, whether read by radiologists or nonradiologists. This editorial commentary will review the relevant issues surrounding CTC interpretation by gastroenterologists. Am J Gastroenterol 2009; 104:2932 -2934 doi: 10.1038/ajg.2009 With proper technique and a robust 3D soft ware platform, some non-radiologists will demonstrate good performance results for computed tomographic colonography (CTC) interpretation in retrospective reader studies (1) . To be clear from the start, I have no fundamental objections to gastroenterologists reading CTC, and welcome any medical professional who is willing and able to provide reasonably accurate interpretations that are free of any secondary gain (e.g., from referral to colonoscopy). However, before gastroenterologists ponder the notion of abandoning their scopes to become, in eff ect, practicing radiologists, there are a number of confounding factors to consider that will likely dampen any initial enthusiasm.Th e National Naval Medical Center in Bethesda, MD, has been instrumental in developing CTC as an eff ective screening tool (2) . Although all clinical CTC studies at this center continue to be interpreted by radiologists, a group of seven gastroenterologists and fellows participated in a retrospective reader study using a subset of CTC cases from the original Department of Defense (DoD) screening trial, the results of which are published in this issue of the American Journal of Gastroenterology (1) . Using a robust CTC soft ware system highly capable of primary 3D evaluation (Viatronix V3D Colon), the reported results were mixed but generally showed good sensitivity for polyp detection, coupled with generally suboptimal specifi city for excluding polyps.I believe some caution is warranted before any comparisons with radiologist performance from the original trial are applied. For one, the current study appears to be considerably underpowered to exclude relevant diff erences (unfortunately, the actual data points are all missing -only the resulting percentages are reported). Furthermore, the polyp prevalence for lesions of relevant size was substantially enhanced for this retrospective study over the screening baseline, which will generally improve lesion detection even if the readers are unaware of the exact prevalence. In addition, formal CTC training was not available for the radiologists before commencing the prospective DoD screening tria...

The second ESGAR consensus statement on CT colonography

“…All panellists agreed that CTC should only be reported by a radiologist, and then only after adequate training [56–59]. Motivations behind this recommendation are mainly the medico-legal implications of non-radiologists reporting CTC in EU countries.…”

CT Colonography for Population Screening: Ready for Prime Time?

“…120 Some motivated gastroenterologists would also likely be able to adequately interpret CTC, although the training involved would be onerous and impractical. 121 …”