Capsule Endoscopists Research Articles

The impact of experience on polyp detection and sizing accuracy at capsule endoscopy: implications for training from an animal model study

Indications for capsule endoscopy include polyp surveillance in Peutz-Jeghers syndrome and potentially colorectal examination and bowel cancer screening. The ability to detect and accurately size polyps associated with these conditions is critical when deciding which patients require further investigation or therapy. Inexperience may affect the ability of capsule endoscopists to perform these skills resulting in sub-optimal patient care. We assessed the performance of volunteers with different levels of endoscopy and capsule endoscopy experience using an animal-based polyp model. Thirty-six artificial polyps were sewn onto the luminal surface of porcine small bowel through which a capsule was propelled. Video images generated by the capsule were then shown to five expert capsule endoscopists, seven consultant gastroenterologists, seven trainee gastroenterologists, six endoscopy nurses, six gastrointestinal radiologists, and six nonmedical participants. Polyp detection rates and sizing accuracy were calculated according to each group and compared. Expert capsule endoscopists had the highest polyp detection rate (91%) but only noncapsule endoscopy experience was independently correlated with improved polyp detection and sizing accuracy (OR missing polyp--endoscopy experience 1.0, no experience 1.96 [95% CI 1.29 - 2.97], P = 0.002; ratio of estimated to actual size--endoscopy experience 1.0, no experience 1.43 [95% CI 1.22 - 1.66], P < 0.001). Both expert capsule endoscopists and experienced endoscopists tended to underestimate polyp size more than novices, particularly for large polyps (OR capsule expert to non-expert: 2.39 vs. 1.0 [95% CI 1.73 - 3.29], P < 0.001). Polyp detection rates and sizing accuracy during capsule endoscopy improve with endoscopic experience. However large polyps, which are the most clinically relevant, are least-accurately sized, and capsule endoscopy experts and experienced endoscopists are the most likely to underestimate the size of these polyps. Training to improve performance in these measures for capsule endoscopy novices as well as experts is required.

Diagnostic yield of capsule endoscopy in ulcerative colitis and inflammatory bowel disease of unclassified type (IBDU)

Capsule endoscopy is increasingly reported as an important diagnostic procedure in patients with known or suspected Crohn's disease, but its clinical utility in patients with ulcerative colitis or unclassified type inflammatory bowel disease (IBDU) is unclear. The aim of our study was to determine the diagnostic yield of capsule endoscopy for small-bowel disease in patients with ulcerative colitis and IBDU. All data from patients with a history of ulcerative colitis or IBDU who underwent capsule endoscopy between October 2001 and August 2005 were analyzed for procedure indications and findings. Images were reviewed by an experienced capsule endoscopist. The finding of multiple ulcerations (three or more) on capsule endoscopy was classified as diagnostic of small-bowel Crohn's disease. 120 patients had undergone 122 capsule endoscopy procedures. Overall, 19 of 120 patients (15.8 %) had capsule endoscopy findings consistent with the diagnosis of Crohn's disease. The proportion of patients with small-bowel disease was significantly higher among patients with a history of colectomy (7 of 21 patients, 33 %) compared with those without colectomy (12/99, 12 %) ( P = 0.04). Among patients with positive findings on capsule endoscopy, 18 had also previously undergone a small-bowel follow-through study and only one showed findings consistent with Crohn's disease. Many patients with a diagnosis of ulcerative colitis and atypical features or IBDU may have small-bowel findings on capsule endoscopy that are consistent with Crohn's disease. Capsule endoscopy should be considered in ulcerative colitis patients with atypical clinical features particularly after colectomy.

Given® Capsule Endoscopy in Celiac Disease: Evaluation of Diagnostic Accuracy and Interobserver Agreement

Capsule endoscopy (CE) has been increasingly used for diagnosing diseases of the small bowel. It is an attractive technique for assessing celiac disease (CD) because it is noninvasive and provides a close and magnified view of the mucosa of the entire small bowel. In this study, we evaluated the accuracy of CE and interobserver agreement in recognizing villous atrophy (VA) using histopathology as the reference. We also explored the extent of small bowel involvement with CD and the relationship between the length of the affected bowel and the clinical presentation. Ten CD patients with histologically proven VA and the same number of controls were subjected to CE. Four, blinded to histology findings, investigators (two with and two without prestudy CE experience) were asked to diagnose VA on CE images. Based on assessment of all four investigators, the overall sensitivity, specificity, PPV, and NPV of CE in diagnosing VA were 70%, 100%, 100%, and 77%, respectively. The sensitivity and the specificity of the test was 100% when the reports of experienced capsule endoscopists only were analyzed. The interobserver agreement was perfect (kappa= 1.0) between investigators with prestudy CE experience and poor (kappa= 0.2) between the investigators who had limited prestudy exposure to CE. Celiac patients with extensive small bowel involvement had typical symptoms of malabsorption (diarrhea, weight loss) as opposed to mild and nonspecific symptoms in patients whose disease was limited to the proximal small bowel. CE was tolerated well by all study participants with 95% reporting absence of any discomfort. Although based on a small sample size, the study suggests that CE may be useful in assessing patients with CD. Familiarity with CE technology appears to be a critical factor affecting the accuracy of the test. Larger studies are warranted to more precisely define the advantages and limitations of CE in CD.

Capsule Endoscopy of the Small Intestine in Graft Versus Host Disease

INTRODUCTION: Graft Versus Host Disease (GVHD)is a well known complication of bone marrow transplant. The small bowel is known to be affected by this disorder. The exact extent and nature of the pathological changes in the small bowel is not well appreciated as this is a difficult area to delineate, specifically in this clinically ill population. We have used capsule endoscopy (CE)in 10 patients thus far with this disorder and report the spectrum of findings. METHODS: 7 Patients with acute and 3 with chronic GVHD were referred for evaluation because of abdominal pain and diarrhea. All patients underwent Capsule Endoscopy with the M2A Capsule Endoscope. All studies were reviewed by two experienced capsule endoscopists. In two patients biopsies of the small bowel were obtained at the time of gastroscopy. One patient underwent repeat Capsule Endoscopy after therapy. RESULTS: In five patients with Grade IV acute GVHD there was extensive and severe small bowel pathology involving the majority of the small bowel. Findings included total loss of villi, severe ulcerations, stricturing and spontaneous bleeding. One patient had a entero-enteric fistula visulized by CE. In one patient with Grade IV acute GVHD capsule endoscopy established the diagnosis. In addition, gastric emptying was markedly delayed in two patients. In three of the cases in this group the cecum was not visualized due to either stricturing or disruption of motility. Histological findings when obtained corroborated the CE findings of severe GVHD without evidence of infection. In two patients with Grade III acute GVHD the CE findings were less severe. In 3 patients with moderate chronic GVHD no mucosal disease was identified. The capsule eventually passed in all cases. CONCLUSION:1. CE is safe in GVHD including Grade IV disease. 2. Severe GVHD affects the entire small bowel causing extensive damage with a large spectrum of findings. 3. Gastric motility may be severly impaired and should be considered when undertaking CE. 4. In chronic GVHD the small bowel mucosa is normal even in the presence of GI symptoms. 5. These findings have direct therapeutic implication in the diagnosis and therapy of Bone Marrow Transplant patients.

Sensitivity and Inter-Observer Variability for Capsule Endoscopy Image Analysis in a Cohort of Novice Readers

Capsule endoscopy image analysis is a time consuming and tedious process. The process for selecting, training, and validating an individual's (reader) ability to accurately detect abnormalities has not been well studied. Aim: To determine the sensitivity, specificity, and concordance rate of novice readers (4th year medical students with minimal endoscopic background) for detecting pre-specified capsule endoscopic findings. Hypotheses: 1) Medical students can reliably detect small bowel lesions deemed as definitive lesions for obscure bleeding with a high degree of sensitivity but low specificity, and 2) the concordance rates between the readers and gold standard will be high. Methods: Ten encoded test cases with definitive sites for bleeding were administered to the readers (n=9) in a pre-set order (bleeding: AVM-3, Meckel's-1, ulcers/aphthous lesions-3, foreign body with ulceration-2). The gold standard findings were pre-defined by 2 expert capsule endoscopists (over 75 capsule cases each). Twelve gold standard targets were identified among the 10 test cases. The readers were given a 30 minute overview of the Rapid Reader (GIVEN Imaging) software and instructions for thumbnailing anatomic landmarks and any potential abnormality. A proprietary software program was developed to compile and analyze thumbnailed finding with respect to sensitivity and specificity as compared to a gold standard and overall concordance rates. Results: The average sensitivity among the 9 medical students was 67% with gradual improvement in sensitivity and specificity over time. All findings were detected by at least 2 to 9 of the students. An average of 19 false positive incidental finding's per case were made by each student. The concordance (Kappa statistic) between readers was 22% for these 12 gold standard findings (intra-class correlation=0.22). Conclusions: A panel of medical students with minimal endoscopic experience can reliably detect high risk bleeding lesions on capsule endoscopy with moderate sensitivity, and can pre-screen recordings to thumbnail potential abnormalities. Due to low specificity, expert capsule endoscopists must review these thumbnails to determine the clinical relevance of each finding. Additional studies are ongoing to assess other reader cohorts (nurses, GI fellows, non-medical) abilities to detect various bleeding as well as non-bleeding abnormalities on capsule endoscopy.