Optimizing the interpretation of capsule endoscopic images: shortsighted or taking the long view?

Capsule endoscopy for the diagnosis and follow up of Crohn's disease: a comprehensive review of current status

Capsule endoscopy (CE) has revolutionized the diagnosis and monitoring of small bowel Crohn’s disease (CD). The procedure is patient friendly and noninvasive, and compared to cross-sectional imaging, CE allows a direct and detailed evaluation of the entire small bowel mucosa with a high sensitivity for the earliest lesions of CD. Today, CE is the leading modality for visualizing the small bowel in suspected CD, and validated activity indices are available for the follow up of patients with established CD. CE of the entire gastrointestinal tract (panenteric CE) was recently introduced as a new diagnostic approach in patients examined for CD, and preliminary results are promising. There are important limitations, involving mainly capsule retention. Furthermore, a diagnostic criterion for CD has never been validated, and lesions detected by CE are not specific for CD. Hence, concern has been raised about a low specificity compared to other diagnostic modalities. Important questions about the optimal bowel preparation, selection of patients for CE and the optimal reading protocol remain to be clarified. The aim of this review is to evaluate the performance of CE for diagnosing CD and assess disease activity in known CD; to compare the diagnostic accuracy of CE to that of cross-sectional imaging; to discuss limitations; and to define the place of CE in the diagnostic algorithm in suspected or known CD.

Impact of the endoscopist's experience on the negative predictive value of capsule endoscopy

INTRODUCTION

The impact of the accumulated experience of the capsule endoscopy (CE) reader on the accuracy of this test is discussed.

AIM

To determine whether the negative predictive value of CE findings changes along the learning curve.

METHODS

We reviewed the first 900 CE read by 3 gastroenterologists experienced in endoscopy over 8 years. These 900 CE were divided into 3 groups (300 CE each): group 1 consisted of the sum of the first 100 CE read by each of the 3 endoscopists; group 2, the sum of the second 100 and groups 3, the sum of the third 100. Patients with normal CE were monitored for at least 28 months to estimate the negative predictive value.

RESULTS

A total of 54 (18%) CE in group 1, 58 (19.3%) in group 2 and 47 (15.6%) in group 3 were normal, although only 34 patients in group 1, 38 in group 2 and 36 in group 3 with normal CE completed follow up and were eventually studied. The negative predictive value was 88.2% in group 1, 89.5% in group 2 and 97% in group 3 (P>.05).

CONCLUSION

The negative predictive value tended to increase, but remained high and did not change significantly after the first 100 when readers are experienced in conventional endoscopy and have preliminary specific training.