Effect of investigator experience in CT colonography

Abstract

The aim of this study was to determine the impact of the learning curve on the diagnostic performances of CT colonography. Two blinded teams, each having a radiologist and gastroenterologist, prospectively examined 50 patients using helical CT scan followed by colonoscopy. Intermediate data evaluation was performed after 24 data sets (group 1) and compared with data from 26 subsequent patients (group 2). Parameters evaluated included sensitivity, specificity, false-positive and false-negative findings, time of data acquisition and interpretation. Using colonoscopy as the gold standard, sensitivity for CT colonography was for lesions >5 mm 63% for both teams for group 1 patients; for group 2 patients sensitivity was 45% for team 1 and 64% for team 2. Specificity per patients was for patient group 1 42% for team 1 and 58% for team 2; for patient group 2 it was 79% for both teams ( p=0.04 for team 1; p=0.2 for team 2). Comparing group 1 with group 2, the number of false-positive findings decreased significantly ( p=0.02). Furthermore, the mean time of data evaluation decreased from 45 to 17 min ( p=0.002) and the mean time of data acquisition from 19 to 17 min. With increasing experience, specificity and the time required for data interpretation improved and false positives decreased. There was no significant change of sensitivity, false-negative findings and time of data acquisition. A minimum experience of the readers is required for data interpretation of CT colonography.

CT colonography: effect of experience and training on reader performance

“…This constant "drip feeding" of CT colonographic- endoscopic correlation is likely to be a more effective educational process than a one-off review of 50 consecutive cases. In a study by Gluecker and colleagues [9], two sets of readers analysed 50 cases but had access to endoscopic findings after first 24; there was no improvement in polyp sensitivity for the second 26 cases compared to the first 24. Alternatively, Pescatore and colleagues [10] found increased detection rates after 25 blinded CT colonographic studies for one individual radiologist, with diagnostic performance continuing to improve as experience approached 100 cases.…”

“…McFarland and colleagues demonstrated that detection of large polyps ranged from 60 to 78%, even amongst experienced abdominal radiologists with equivalent colonographic training [11]. Furthermore, reader performance has been shown to continue to improve after just 25 cases [9,10]. At the present time, there is no consensus regarding what represents adequate reader training for CT colonography, probably because there is little evidence on which to base assumptions.…”

“…To date, there has been relatively little work on the effect of technique-specific training or overall radiologist experience on the diagnostic performance of CT colonography [9,10]. McFarland and colleagues demonstrated that detection of large polyps ranged from 60 to 78%, even amongst experienced abdominal radiologists with equivalent colonographic training [11].…”

Colonic surveillance by CT colonography using axial images only

“…The use of 3D and MPR images in CT colonography requires dedicated software and familiarity with these image-manipulation techniques. It has been recommended that radiologists be trained in such techniques prior to interpreting CT colonography studies in a clinical setting [22]. In a busy department staffed by general radiologists, it may not be practical to devote the effort to including CT colonography in the routine work list.…”

Computed Tomographic and Magnetic Resonance Colonography: Challenge for Colonoscopy

“…Additionally, there appears to be a ‘learning curve’ associated with learning how to read CT colonography. Some investigators have found that accuracy increased after reading 25 cases [68], while in another study, sensitivity improved after reading 50 cases and appeared ideal after interpreting 75 cases [69]. In a study with novice readers, specifically medical students and radiology technologists, after training using a teaching file of 50 cases followed by blind interpretation of 50 cases, these readers performed similarly to radiologists and improved in proportion to case volume up to 100 cases [64].…”