A rapid and accurate method to detect active small bowel gastrointestinal bleeding on video capsule endoscopy

Artificial intelligence within the small bowel: are we lagging behind?

PURPOSE OF REVIEW

The use of artificial intelligence in small bowel capsule endoscopy is expanding. This review focusses on the use of artificial intelligence for small bowel pathology compared with human data and developments to date.

RECENT FINDINGS

The diagnosis and management of small bowel disease has been revolutionized with the advent of capsule endoscopy. Reading of capsule endoscopy videos however is time consuming with an average reading time of 40 min. Furthermore, the fatigued human eye may miss subtle lesions including indiscreet mucosal bulges. In recent years, artificial intelligence has made significant progress in the field of medicine including gastroenterology. Machine learning has enabled feature extraction and in combination with deep neural networks, image classification has now materialized for routine endoscopy for the clinician.

SUMMARY

Artificial intelligence is in built within the Navicam-Ankon capsule endoscopy reading system. This development will no doubt expand to other capsule endoscopy platforms and capsule endoscopies that are used to visualize other parts of the gastrointestinal tract as a standard. This wireless and patient friendly technique combined with rapid reading platforms with the help of artificial intelligence will become an attractive and viable choice to alter how patients are investigated in the future.

Association between hypokalemia and small bowel capsule endoscopy completion rates in patients in South China: A prospective single-center study

BACKGROUND/AIMS

Approximately 20-30% of small bowel capsule endoscopies (SBCEs) do not reach the cecum at the completion of the examination. We aimed to determine whether hypokalemia influences the completion rate and small bowel transit time (SBTT) of SBCE.

PATIENTS AND METHODS

From January to December 2017, 112 patients (18-75 years old) who underwent SBCE were assessed consecutively for enrolment in our study. On the day of the procedure, a blood test was performed prior to capsule ingestion. The completion rate, gastric transit time (GTT), SBTT, and diagnostic yield were recorded for each SBCE.

RESULTS

The SBCE completion rate was lower in the hypokalemia group than that in the normal potassium group (55.6% (15/27) vs. 76.5% (65/85), P = 0.036). The median GTT was 55.5 ± 47.1 min in the hypokalemia group and 46.7 ± 44.5 min in the normal potassium group (P > 0.05). The median SBTT was 412.8 ± 123.3 min in the hypokalemia group and 367.3 ± 172.5 min in the normal potassium group (P > 0.05). The diagnostic yields of the hypokalemia and normal potassium groups were 74.1% and 78.8%, respectively (P = 1.00).

CONCLUSION

Hypokalemia may decrease the SBCE completion rate. Physicians should consider the possibility of hypokalemia after bowel preparation because this condition is not rare. Potassium deficiencies should be rectified prior to performing SBCE procedures to increase the SBCE completion rate.

Suspected Blood Indicator to Identify Active Gastrointestinal Bleeding: A Prospective Validation

Background

The suspected blood indicator (SBI) function in the RAPID Reader v8.3 program was designed to quickly identify the presence of blood in video capsule endoscopy. While previous retrospective studies have shown that the SBI function was accurate in detecting the presence of active bleeding in the small bowel, its specificity and sensitivity were poor.

Methods

An initial retrospective review (phase 1) compared 115 patients with active gastrointestinal bleeding seen on video capsule endoscopy (VCE) to 115 patients with no active bleeding seen on VCE to produce a highly accurate algorithm. A prospective study (phase 2) was then performed by applying the algorithm to 100 consecutive patients who received VCE for the following indications: obscure bleeding, iron deficiency anemia, melena, and hematochezia.

Results

The initial retrospective review found that eight contiguous SBI markers had a specificity of 100% in identifying active gastrointestinal bleeding regardless of the total number of SBI markers, while two or more contiguous SBI markers had a sensitivity of 96.5%. Using a cutoff of eight contiguous SBI markers, the prospective arm found that there was a 100% sensitivity and specificity in detecting active gastrointestinal bleeding (P < 0.001).

Conclusions

The SBI function can greatly facilitate the identification of active gastrointestinal bleeding on VCE by using eight contiguous SBI markers as a cutoff for active bleeding.

The validity of suspected blood indicator software in capsule endoscopy: a systematic review and meta-analysis

Software tools have been developed as capsule endoscopy (CE) reading aids. The suspected blood indicator (SBI) tags possible areas of haemorrhage in the gastrointestinal (GI) tract. This meta-analysis aims to investigate the diagnostic accuracy of SBI in CE. Areas covered: A systematic literature search was conducted for studies on the use of SBI in CE. Sensitivity, specificity and diagnostic odds ratio (DOR) of SBI in diagnosing GI bleeding was evaluated. 2040 patients from 16 studies underwent 2049 CE examinations. The overall sensitivity of SBI for bleeding or potentially bleeding lesions was 0.553, specificity 0.578, DOR 12.354. The sensitivity of SBI for active bleeding was 0.988, specificity 0.646, DOR 229.89. Expert commentary: Currently, SBI has limited validity in CE reading. However, in active GI bleeding, it has good sensitivity, supporting its use in the acute setting.

Evaluation of performance of the Omni mode for detecting video capsule endoscopy images: A multicenter randomized controlled trial

BACKGROUND AND STUDY AIMS

Olympus recently developed a new algorithm called Omni mode that discards redundant video capsule endoscopy (VCE) images. The current study aimed to demonstrate the non-inferiority of the Omni mode in terms of true positives (TPs) and the superiority of the Omni mode with regard to reading time against a control (ordinary ES-10 system).

PATIENTS AND METHODS

This multicenter prospective study included 40 patients with various small bowel diseases. VCE images were evaluated by 7 readers and 3 judging committee members. Two randomly allocated readers assessed the VCE images obtained using the 2 modalities for each patient. The order of the modalities was switched between the 2 readers and the interval between readings by the same reader was 2 weeks. The judging committee predefined clinically relevant lesions as major lesions and irrelevant lesions as minor lesions. The number of TPs for major and minor lesions and the reading times were compared between the modalities. The predefined non-inferiority margin for the TP ratio of the Omni mode compared with the control was 0.9.

RESULTS

The estimated TP ratios and 95 % confidence intervals for total, major, and minor lesions were 0.87 (0.80 - 0.95), 0.93 (0.83 - 1.04), and 0.83 (0.74 - 0.94), respectively. Although non-inferiority was not demonstrated, the rate of detection of major lesions was not significantly different between the modalities. The reading time was significantly lower when using the Omni mode than when using the control.

CONCLUSIONS

The Omni mode may be only appropriate for the assessment of major lesions.

Small Bowel Endoscopy

OPINION STATEMENT

The small bowel is a challenging area for endoscopic evaluation and therapy due to its length and angulated configuration. A small lumen diameter and segmental peristalsis made it a perfect fit for examination by a novel ingestible wireless camera in a capsule. The development of capsule endoscopy changed the diagnosis and management of bleeding lesions, ulcers, and tumors deep in the small bowel, allowing earlier diagnosis with excellent patient acceptance. Device-assisted enteroscopy revolutionized small bowel therapy, particularly management of bleeding, Peutz-Jeghers polyposis, and tumor marking for minimally invasive surgery. Small bowel stricture dilation in select patients is safe and effective. Tools for a spectrum of small bowel therapies are available but remain suboptimal to tackle lesions on angulated folds deep in the small bowel. Universal terminology to describe the endoscopic appearance of vascular lesions will facilitate studies of endoscopic and medical therapy. The future holds improvements in imaging, easier advancement through the small bowel, and therapeutic capacity. This review focuses on methods of small bowel endoscopy, therapy, and outcomes.