Capsule endoscopy (CE) enables evaluation of the entire mucosal surface of the small bowel (SB), which is one of the most important steps for evaluating obscure gastrointestinal bleeding. Although the diagnostic yield of SB CE depends on many clinical factors, there are no reports on quality indicators. Thus, the Korean Gut Image Study Group (KGISG) publishes an article titled, “Quality Indicators for Small Bowel Capsule Endoscopy” under approval from the Korean Society of Gastrointestinal Endoscopy (KSGE). Herein, we initially identified process quality indicators, while the structural and outcome indicators are reserved until sufficient clinical data are accumulated. We believe that outcomes of SB CE can be improved by trying to meet our proposed quality indicators.
Capsule endoscopy (CE) was introduced in 2000 [
CE is the best method to evaluate the entire mucosal surface of the SB and it plays a key role in evaluation of obscure gastrointestinal bleeding (OGIB). However, the diagnostic yield of SB CE can be affected by many factors, such as indications, bowel preparation, technical errors, view mode and frame rate during interpretation, reviewers’ experience, and so on.
Diagnostic procedures with inadequate quality may be related with decreased diagnostic accuracy, procedure-related complications, and unnecessary medical burden. However, there are no publications on quality indicators for SB CE. Thus, the members of Korean Gut Image Study Group (KGISG) decided to establish “Quality Indicators for Small Bowel Capsule Endoscopy” under approval from the Korean Society of Gastrointestinal Endoscopy (KSGE).
Generally, quality indicators refer to specific issues identified for comparison and potential improvement [
We believe the following quality indicators will be helpful to establish competence of CE and to improve quality of CE.
Three taskforce teams (preprocedure, intraprocedure, and postprocedure) from KGISG were formed and each team performed systematic literature search and prepared a comprehensive review to identify articles relevant to CE since the year 2000, using PubMed, MEDLINE, KoreaMed, and Google Scholar. Each team generated indicator candidates. Finally, 16 quality indicators were selected after repetitive discussions. Each candidate indicator, proposed by a team, was reviewed and discussed by other teams in a crossover manner. The grades of recommendation were classified in
Capsule endoscopy is recommended as the first-line investigation for patients with obscure gastrointestinal bleeding (grade of recommendation: 1A).
The overall diagnostic yield of CE for OGIB ranges between 30% and 70%, which is higher than that of other diagnostic modalities (push enteroscopy, double-balloon enteroscopy [DBE], and SB series with sensitivities of 31%, 23%, and 5%, respectively) [
Capsule endoscopy is the most sensitive diagnostic modality for detecting mucosal lesions of the small bowel in patients with suspected or established Crohn’s disease (grade of recommendation: 1B).
CE plays a role in diagnosing suspected Crohn’s disease (CD) when the clinical history is compatible, but not as much as diagnostic ileocolonoscopy. SB endoscopy helps to make differential diagnosis of CD in suspected CD patients by identifying SB involvement proximal to the terminal ileum. It also plays a role in the mucosal severity of the SB and disease extension in patients with established CD [
Capsule endoscopy is useful for detection of small bowel tumors and polyps (grade of recommendation: 2C).
CE is recommended for patients with OGIB to find SB tumor. However, DAE is preferred rather than CE in patients with SB tumor-suspected images [
The use of CE for suspected celiac disease is not routinely recommended. However, it is suggested to use CE in patients unwilling or unable to undergo conventional endoscopy [
CE has a low diagnostic yield in patients with abdominal pain (13%); however, the diagnostic yield of CE can be improved in patients with chronic abdominal pain accompanied with elevated serum inflammatory markers (C-reactive protein, erythrocyte sedimentation rate), weight loss, diarrhea, and so on [
In patients with Crohn’s disease, previous abdominal surgery, intestinal ischemia, volvulus, and history of abdominal radiotherapy, the risk of capsule retention is increased. For risk stratification and prevention of capsule retention, taking careful clinical history and performing careful physical examination is essential (grade of recommendation: 3).
The capsule is usually excreted with feces within 24–48 hours of ingestion. Capsule retention (CR) is defined as having a capsule remain in the GI tract for more than 2 weeks or requiring directed surgical or endoscopic intervention [
In cases of CD, up to 66% of patients have SB involvement at diagnosis. Twenty-five percent of patients with CD have had at least one SB stricture [
In subjects with Crohn’s disease, obstructive symptoms, and suspicious stenosis, small bowel imaging, such as computed tomography enterography or magnetic resonance enterography, should be methods of choice for patency of small bowel prior to subsequent capsule endoscopy. Additionally, the use of patency capsule to confirm the functional patency of small bowel is recommended (grade of recommendation: 2C).
Since CTE/CT enteroclysis or MR enterography (MRE)/MR enteroclysis could identify strictures and assess the transmural or extraluminal nature of the disease, if subjects have obstructive symptoms or suspicious stenosis, dedicated SB cross-sectional imaging with CTE or MRE generally takes precedence over CE for evaluation of the SB [
Patency capsule is used before CE to evaluate the patency of the GI tract in patients with stricture or suspected stricture [
Intraprocedural and postprocedural patient instructions should be provided in written form before performing small bowel capsule endoscopy (grade of recommendation: 3).
Little is known about whether the diagnostic yield or quality of CE can be influenced by the intraprocedural and postprocedural patient instructions. In general, the manufacturer’s guidelines include the acceptable physical activity and dietary intake after swallowing the capsule to ensure successful tests [
Excellent or good preparation (>75% small bowel visualization) is considered to enhance diagnostic yield of small bowel examination (grade of recommendation: 1C).
During CE, several factors, such as bubbles, food material in the SB, and gastric and SB transit time, influence the SB visualization quality (SBVQ), diagnostic yield, and cecal completion rate were analyzed. Therefore, bowel preparation prior to CE is as important as bowel preparation prior to colonoscopy. Diagnostic yield is defined as a meaningful diagnostic finding of CE. Purgative bowel preparations enhance diagnostic yield of SB examination using CE [
SBVQ was defined as follows: “excellent,” if an ideal visualization of the SB mucosa was achieved (>90%); “good,” if >75% of the mucosa was in perfect condition; “fair,” if only 50%–75% of the mucosa was under perfect conditions; and “poor,” if <50% of the mucosa could be observed. However, there was no consensus of optimal bowel preparation for CE, as each study with polyethylene glycol (PEG) suggested various definitions for bowel preparation quality. A recent study considered excellent or good preparation (>75% SB visualization) as an adequate bowel preparation [
Bowel preparation with purgatives enhances the small bowel visual quality compared with fasting alone or a clear liquid diet (grade of recommendation: 1B).
To date, there have been many comparative studies, consensus, and guidelines regarding different types of bowel cleansing agents in bowel preparation for CE [
According to the guidelines for bowel preparation, which were published by the KGISG in 2013 [
Currently, there has been no consensus regarding optimal timing of bowel preparation before CE. A 2-L PEG-based purge, administered one day prior, is the most commonly used preparation method. In clinical practice, CE exam is followed by colonoscopy in patients with obscure GI bleeding or CD. Therefore, the timing of bowel preparation is frequently dependent on the time of colonoscopic examination. According to a single center study by Black et al., [
Photodocumentation of capsule passing through the ileocecal valve or into the colon is necessary for verification of entire small bowel exploration (grade of recommendation: 2C).
Although CE is a useful tool for evaluating SB disease, it is impossible to visualize the entire SB in all patients because capsules have not always passed through the ileocecal valve before battery exhaustion due to various reasons [
Complete examination was defined as capsule passing through the ileocecal valve or into the colon on images during its working time [
The incomplete examination rate of the CE based on the 10-year data from the Korean CE registry was 33% (969/2,914) [
Hospitalization, history of SB surgery, and delayed gastric emptying had been shown to be risk factors for incomplete examination [
When capsule endoscopy is performed in patients with high risk of delayed gastric emptying, identifying capsule’s position using plain radiography or real-time viewer after ingestion, or endoscopic employment of capsule endoscopy is recommended (grade of recommendation: 1B).
Gastric retention resulting in capsule failing to enter the duodenum and delayed gastric transit, remaining in the stomach for more than 1–1.5 hours had been known as the major causes for incomplete examination [
The effects of routine use of prokinetics, such as metoclopramide and erythromycin, to enhance gastric transit were inconsistent [
Identifying capsule’s position using plain radiography or real-time viewer two hours after ingestion is recommended as the effective method to reduce gastric transit time, especially in patients who are more likely to have delayed gastric transit. Particularly, use of external real-time viewer to check the progress of the capsule and prespecified actions, such as additional water swallowing, administration of prokinetics, and endoscopic delivery, significantly improved the completion rate [
Although it is invasive, endoscopic delivery of capsule to the duodenum has been used as an optimal method to reduce gastric transit time. Additionally, it can be useful in patients with high risk of delayed gastric emptying, particularly in patients with diabetes, vagotomy, scleroderma, or ongoing hospitalization [
Technical errors during capsule endoscopy procedure can decrease quality of capsule endoscopy images, although, it seldom occurs (grade of recommendation: 3).
CE image is of significant importance, because high-quality images provide more information for diagnosis. It is not satisfactory mainly because of factors that reduce CE quality. Images obtained during CE are exposed to different types of noise; for example, food and gas in the stomach, SB, or colon can reduce image quality. Captured images tend to have technical errors [
Together, results of previous studies allow technical errors to be divided into two types: CE system-related error (communication and transmission error) and patient-related error. CE system-related errors include low resolution, blurred images, and light-related distortions. One of the typical noise types in the capsule image was due to data communication errors [
Hence, CE image quality plays a critical role in diagnosis. Although there are no published reports of the technical error rate in practice, it is generally considered to be very low. However, because technical errors during the CE procedure are associated with quality of the CE image, these need to be reported more carefully. Based on these results, action should be taken to solve or reduce technical errors for better quality CE images.
DualView or QuadView may be recommended as the viewing mode to improve reading efficiency and detection rate of interpreters reading capsule endoscopy (grade of recommendation: 2C).
To date, there is no optimal view mode for the best interpretation of CE. However, the appropriate selection image number at the monitor improves reading efficiency and detection rate of interpreters reading CE [
A previous study evaluated the effect on the SB using 10 selected video clips. The playing time from the entry of the capsule into the duodenal bulb to the cecum, without the video being stopped once started, was determined by 11 different combinations of video mode and frame rates in order to evaluate the impact of view mode on reading time and detection rates of lesions. There was no difference in reading time according to view mode at the same frame rate [
During capsule endoscopy reading, 15 frames per second or less is appropriate for acceptable detection rate (grade of recommendation: 2C).
The frame rate means the number of f.p.s that is displayed in a video file by softwares for CE reading. Currently, these softwares provide a various range of frame rates allowing reduction of reading time of thousands of capsule’s images [
According to a panel consensus of 2002 International Conference of Capsule Endoscopy, the fastest acceptable frame rate of review was 15 f.p.s [
Experience with minimum of 10–20 capsule endoscopy cases is required for trainees to attain capsule endoscopy competency (grade of recommendation: 1C). Because the lesion miss rate during capsule endoscopy is relative high, interpretation of findings in capsule endoscopy should be done by experienced and competent endoscopists. Interpretation performed by a trainee should be reviewed and confirmed by an expert (grade of recommendation: 2C).
The utility of CE as a diagnostic tool depends on the accuracy of interpretation. However, lesion miss rate is high possibly because only a small fraction of images shows clinically significant lesions during the reading of capsule images [
However, the effect of interpreter’s experience on detection of lesions during CE reading has not been fully determined. A recent study including 17 endoscopists with experience from 23 to over 1,000 total CE procedures showed that experience of capsule reading did not significantly affect detection rate: 17% of the interpreters with the lowest detection rates had reading experience of more than 300 capsules [
Either conservative or endoscopic treatment can be considered for capsule retention, and the decision depends on patient’s symptoms or availability of enteroscopy. Surgical removal of retained capsule could be reserved for asymptomatic patients (grade of recommendation: 3).
CE has been proved to be an effective and safe device in the diagnosis of SB disease with few complications or adverse effects. Retention of capsule, perforation, aspiration, and SB obstruction are reported as complications of CE. Among these, CR is the most common complication. Retained capsules are usually asymptomatic but may cause partial or complete intestinal SB obstruction in some patients. Several cases where a CR leads to intestinal perforation have been reported [
Procedure reports are required for every capsule endoscopy and should be accurate, concise, and completed in a timely manner (grade of recommendation: 3).
Accurate and timely documentation of capsule endoscopic findings and recommendations improve patients care. The task force emphasizes that the CE report should be detailed. The patient’s medical history justifying the CE should be described. The indications are classified into signs and symptoms, and diseases. Standardization of the language and structure of endoscopic reports based on CE structured terminology (CEST) may improve communication between clinicians [
We expect that the outcome of SB CE can be improved by trying to meet the abovementioned 16 quality indicators. Improvement of the outcomes should be confirmed by following studies. Continuous process of quality improvement should be followed.
Supplementary materials are available at
Grade of Recommendation
Grade of recommendation | Clarity of benefit | Methodologic strength supporting evidence | Implications |
---|---|---|---|
1A | Clear | Randomized trials without important limitations | Strong recommendation, can be applied to most clinical settings |
1B | Clear | Randomized trials with important limitations (inconsistent results, nonfatal methodologic flaws) | Strong recommendation, likely to apply to most practice settings |
1C+ | Clear | Overwhelming evidence from observational studies | Strong recommendation, can apply to most practice settings in most situations |
1C | Clear | Observational studies | Intermediate-strength recommendation, may change when stronger evidence is available |
2A | Unclear | Randomized trials without important limitations | Intermediate-strength recommendation, best action may differ depending on circumstances or patients ’ or societal values |
2B | Unclear | Randomized trials with important limitations (inconsistent results, nonfatal methodologic flaws) | Weak recommendation, alternative approaches may be better under some circumstances |
2C | Unclear | Observational studies | Very weak recommendation, alternative approaches likely to be better under some circumstances |
3 | Unclear | Expert opinion only | Weak recommendation, likely to change as data become available |
Adapted from Guyatt et al. [
Summary of Proposed Quality Indicators Common to Small Bowel Capsule Endoscopy
Quality indicator | Grade of recommendation | Measure type |
---|---|---|
Preprocedural | ||
Capsule endoscopy is recommended as the first-line investigation for patients with obscure gastro-intestinal bleeding. | 1A | Process |
Capsule endoscopy is the most sensitive diagnostic modality for detecting mucosal lesions of the small bowel in patients with suspected or established Crohn’s disease. | 1B | Process |
Capsule endoscopy is useful for detection of small bowel tumors and polyps. | 2C | Process |
In patients with Crohn’s disease, previous abdominal surgery, intestinal ischemia, volvulus, and history of abdominal radiotherapy, the risk of capsule retention is increased. For risk stratification and prevention of capsule retention, taking careful clinical history and performing careful physical examination is essential. | 3 | Process |
In subjects with Crohn’s disease, obstructive symptoms, and suspicious stenosis, small bowel imaging, such as computed tomography enterography or magnetic resonance enterography, should be methods of choice for patency of small bowel prior to subsequent capsule endoscopy. Additionally, the use of patency capsule to confirm functional patency of the small bowel is recommended. | 2C | Process |
Intraprocedural and postprocedural patient instructions should be provided in written form before performing small bowel capsule endoscopy. | 3 | Process |
Intraprocedural | ||
Excellent or good preparation (>75% small bowel visualization) is considered to enhance diagnostic yield of small bowel examination. | 1C | Process |
Bowel preparation with purgatives enhances the small bowel visual quality compared with fasting alone or a clear liquid diet. | 1B | Process |
Photodocumentation of capsule passing through the ileocecal valve or into the colon is necessary for verification of entire small bowel exploration. | 2C | Process |
When capsule endoscopy is performed in patients with high risk of delayed gastric emptying, identifying capsule’s position using plain radiography or real-time viewer after ingestion, or endoscopic employment of capsule endoscopy is recommended. | 1B | Process |
Technical errors during capsule endoscopy procedure can decrease quality of the capsule endoscopy image, although, it seldom occurs. | 3 | Process |
Postprocedural | ||
DualView or QuadView may be recommended as the viewing mode to improve reading efficiency and detection rate of interpreters reading capsule endoscopy. | 2C | Process |
During capsule endoscopy reading, 15 frames per second or less is appropriate for acceptable detection rate. | 2C | Process |
Experience with minimum of 10–20 capsule endoscopy cases is required for trainees to attain capsule endoscopy competency. Because the lesion miss rate during capsule endoscopy is relatively high, interpretation of findings in capsule endoscopy should be done by experienced and competent endoscopists. Interpretation performed by a trainee should be reviewed and confirmed by an expert. | 1C and 2C | Process |
Either conservative or endoscopic treatment can be considered for capsule retention, and the decision depends on patient’s symptoms or availability of enteroscopy. Surgical removal of retained capsule could be reserved for asymptomatic patients. | 3 | Process |
Procedure reports are required for every capsule endoscopy and should be accurate, concise, and completed in a timely manner. | 3 | Process |
Korean Standard of Capsule Endoscopy Report
Korean Standard of Capsule Endoscopy Report | |
---|---|
1. | Institute or Hospital: |
2. | Patient: |
Name: | |
Age/Sex: | |
Hospital registration No: | |
3. | Date of study: (d)/(m)/(yr) |
4. | CE company: Given |
IntroMedic (MiroCam) | |
Olympus | |
Others | |
5. | CE type: SB/esophagus/colon/stomach |
6. | Doctor: Ordered by Dr. |
Interpreted by Dr. |
|
7. | History |
i) Medical history: none/diabetes mellitus/thyroid disease/hypertension/tuberculosis/renal disease/liver disease/surgery/others: | |
ii) Recent drug history: none/NSAID/aspirin/steroid/anticoagulant/others: | |
8. | Clinical indications for CE |
i) Symptom: abdominal pain/chronic diarrhea/weight loss/melena | |
ii) Sign: anemia/obscure GI bleeding, overt/obscure GI bleeding, occult/protein-losing enteropathy | |
iii) Diseases: CD/ulcerative colitis/intestinal tuberculosis/polyposis/intestinal tumor or mass/intestinal ischemia/Celiac sprue/Behçet disease/lymphoma | |
iv) Others | |
9. | Contraindications for CE |
i) Known or suspected GI obstruction, stricture, or fistulas based on the clinical picture or pre-procedure testing (CT or MRE, patency capsule, SB series) | |
ii) Pediatrics (less than 9 years) | |
iii) Swallowing disorder | |
iv) Pregnancy | |
v) Others | |
10. | Onset of chief complaints: days/months/years ago |
11. | Studies done before CE |
i) None | |
ii) Choose multiple if performed: EGD/colonoscopy/US/CT/SB series/push enteroscopy/DBE/MRI/angiography/PET/others | |
iii) Result of pre-CE studies: | |
negative | |
suspiciously positive | |
positive, compatible with CE | |
positive, independently with CE | |
12. | Characteristics of CE examination |
i) Preparation technique: NPO only/PEG 4 L/PEG 2 L/Fleet/simethicone | |
ii) Use of prokinetics: none/metoclopramide/erythromycin/mosapride/domperidone/alaxyl/others | |
iii) Preparation quality: excellent/adequate/inadequate, but exam completed/inadequate, precluding exam | |
iv) Visualization quality: excellent/inadequate illumination/inadequate preparation | |
v) Type of equipment malfunction: none/capsule/recorder/others | |
vi) Endoscopic delivery into duodenum: yes/no | |
13. | Extent of examination |
i) Total battery time: | |
ii) Stomach transit time: | |
iii) SB transit time: | |
iv) The furthest identifiable anatomic site: esophagus/stomach/jejunum/ileum/ileocecal valve/right colon/left colon/rectum | |
14. | Complication: none/CE retention/aspiration |
i) If retention occurred, | |
Site: esophagus/stomach/jejunum/ileum | |
Cause: gastroparesis/gut stenosis/others/unknown | |
Outcome: spontaneous pass-out/medical/endoscopic removal/surgical removal/observation still now | |
Day of elimination: days | |
ii) If aspiration occurred, | |
Treatment: none/endoscopic removal/surgical removal | |
15. | Findings |
i) Major: | |
ii) Minor: | |
iii) Minor: | |
16. | Diagnostic impression |
i) |
|
ii) Level of certainty: established of/suspicious of/exclusion of/follow up of in addition, | |
17. | Studies done after CE |
None/EGD/colonoscopy/US/SB series/push enteroscopy/DBE or single balloon enteroscopy/CT/MRI/angiography/PET/others | |
Result of post-CE studies: negative/suspiciously positive/positive, compatible with CE/positive, independently with CE | |
18. | Process after CE diagnosis |
i) Observation with assumption of benign condition/due to patient’s refusal to treat | |
ii) Medication | |
iii) Endoscopic treatment, EGD/colonoscopy/push enteroscopy/DBE | |
iv) Surgery | |
v) Follow up lost | |
vi) Other |
Adapted from Gut Image Study Group [
CE, capsule endoscopy; SB, small bowel; NSAID, non-steroidal anti-inflammatory drug; GI, gastrointestinal; CD, Crohn’s disease; CT, computed tomography; MRE, magnetic resonance enterography; EGD, esophagogastroduodenoscopy; US, ultrasonography; DBE, double-balloon enteroscopy; MRI, magnetic resonance imaging; PET, positron emission tomography; NPO, nothing per oral; PEG, polyethylene glycol.