Magnetic resonance imaging compatibility of endoclips

Safety Issues in Magnetic Resonance Imaging Scan with Retention of Olympus Long Clips in the Gastrointestinal Tract

OBJECTIVE

Not all endoscopic clips are compatible with magnetic resonance imaging (MRI). The aim of this study is to investigate the safety of MRI-incompatible endoscopic clips in patients undergoing MRI scans.

METHODS

We retrospectively reviewed the medical records of patients who had received endoscopic clip placement of Olympus Long Clip MRI-incompatible clips and then had undergone MRI scans within two weeks in our hospital between 2014 and 2019.

RESULTS

A total of 44,292 patients had undergone an MRI examination at our hospital. Only 15 patients had MRI scans within two weeks after the endoscopic clip placement. Their median age was 65.5 years, and 12 of the 15 patients were men. At the time of the clip placement and MRI scan, four patients were taking anti-coagulation or anti-platelet agents. The indication for endoscopic clip placement of the 15 patients was mucosal/submucosal defect or hemorrhage and colonic perforation. Endoscopic clips were placed in the colon of 14 patients and in the stomach of only one patient for gastric hemorrhage. One patient experienced clip migration and three displayed artifacts in abdominal images. No patient complications of mortality, hemorrhage, or organ perforation occurred.

CONCLUSION

No serious adverse event occurred during MRI scans of patients with MRI-incompatible clips in this study, suggesting that MRI-incompatible clips may be safe to use in MRI scans. However, this does not guarantee the safety of the Long Clip for MRI scans, as further tests are needed to verify that this clip is safe for use during MRI.

Compatibility of endoclips in the gastrointestinal tract with magnetic resonance imaging

There are no clear guidelines on the compatibility between endoclips that remain in the gastrointestinal (GI) tract and magnetic resonance imaging (MRI). The purpose of this study was to investigate the effect of 3T (T) MRI on endoclips placed in excised pig tissues. Two types of endoclips were assessed: Olympus EZ (HX-610-135L) and QuickClip Pro (HZ-202LR). We assessed tissue damage or perforation and detachment of endoclips under 3T MRI magnetic field. We also evaluated the magnitude of force required to detach the endoclips from the porcine tissue. We measured the magnetic force acting on the Olympus EZ clips. QuickClip Pro clips were used as a control in this study. There was no tissue damage and no detachment of the endoclips (Olympus EZ and QuickClip Pro) during 3T MRI. The force required to detach the Olympus EZ clips ranged from 0.9 to 3.0 N. The translational magnetic force acting on the endoclips was 3.18 × 10^-3 N. Ex vivo experiments showed that the magnetic field generated by 3 MRI did not cause tissue damage or perforation and did not detach the endoclips. Olympus EZ clips and QuickClip Pro clips in the GI tract appear to be safe during 3T MRI.

Endoclip Magnetic Resonance Imaging Screening: A Local Practice Review

PURPOSE

Not all endoscopically placed clips (endoclips) are magnetic resonance imaging (MRI) compatible. At many institutions, endoclip screening is part of the pre-MRI screening process. Our objective is to determine the contribution of each step of this endoclip screening protocol in determining a patient's endoclip status at our institution.

METHODS

A retrospective review of patients' endoscopic histories on general MRI screening forms for patients scanned during a 40-day period was performed to assess the percentage of patients that require endoclip screening at our institution. Following this, a prospective evaluation of 614 patients' endoclip screening determined the percentage of these patients ultimately exposed to each step in the protocol (exposure), and the percentage of patients whose endoclip status was determined with reasonable certainty by each step (determination).

RESULTS

Exposure and determination values for each step were calculated as follows (exposure, determination): verbal interview (100%, 86%), review of past available imaging (14%, 36%), review of endoscopy report (9%, 57%), and new abdominal radiograph (4%, 96%), or CT (0.2%, 100%) for evaluation of potential endoclips. Only 1 patient did not receive MRI because of screening (in situ gastrointestinal endoclip identified).

CONCLUSIONS

Verbal interview is invaluable to endoclip screening, clearing 86% of patients with minimal monetary and time investment. Conversely, the limited availability of endoscopy reports and relevant past imaging somewhat restricts the determination rates of these. New imaging (radiograph or computed tomography) is required <5% of the time, and although costly and associated with patient irradiation, has excellent determination rates (above 96%) when needed.

New and emerging endoscopic haemostasis techniques

Endoscopic treatment has been accepted as first-line treatment of upper gastrointestinal bleeding, both for variceal as well as for non-variceal haemorrhage. Dual modality treatment including injection therapy with mechanical or thermal haemostatic techniques has shown superior outcome compared with injection monotherapy in non-variceal bleeding. During recent years, new endoscopic devices have been developed and existing endoscopic techniques have been adapted to facilitate primary control of bleeding or achieve haemostasis in refractory haemorrhage. For mechanical haemostasis, larger, rotatable and repositionable clips have been developed; multiple-preloaded clips are also available now. Over the scope clips allow to ligate larger vessels and can close ulcer defects up to 20 mm. Topical, easily applied substances withdraw fluid from the blood and thereby initiate blood clotting. This can be helpful in diffuse oozing bleeding, for example, from tumour or hypertensive gastropathy and has also shown promising results in variceal and arterial bleeding as bridging before definitive treatment is available. Radiofrequency ablation and multiband ligation have emerged as new tools in the endoscopic management of gastric antral vascular ectasia. In acute refractory variceal bleeding, a covered and removable oesophagus stent can provide tamponade and gain time for transport to an interventional endoscopic centre or for radiological intervention such as TIPS.

Which clip? A prospective comparative study of retention rates of endoscopic clips on normal mucosa and ulcers in a porcine model

BACKGROUND/AIM

There are currently no data on the relative retention rates of the Instinct clip, Resolution clip, and QuickClip2Long. Also, it is unknown whether retention rate differs when clips are applied to ulcerated rather than normal mucosa. The aim of this study is to compare the retention rates of three commonly used endoscopic clips.

MATERIALS AND METHODS

Six pigs underwent upper endoscopy with placement of one of each of the three types of clips on normal mucosa in the gastric body. Three mucosal resections were also performed to create "ulcers." Each ulcer was closed with placement of one of the three different clips. Repeat endoscopy was performed weekly for up to 4 weeks.

RESULTS

Only the Instinct and Resolution clips remained attached for the duration of the study (4 weeks). At each time point, a greater proportion of Instinct clips were retained on normal mucosa, followed by Resolution clips. QuickClip2Long had the lowest retention rate on normal mucosa. Similar retention rates of Instinct clips and Resolution clips were seen on simulated ulcers, although both were superior to QuickClip2Long. However, the difference did not reach statistical significance. All QuickClip2Long clips were dislodged at 4 weeks in both the groups.

CONCLUSIONS

The Resolution and Instinct clips have comparable retention rates and both appeared to be better than the QuickClip2Long on normal mucosa-simulated ulcers; however this did not reach statistical significance. Both the Resolution clip and the Instinct clip may be preferred in clinical situations when long-term clip attachment is required, including marking of tumors for radiotherapy and anchoring feeding tubes or stents. Either of the currently available clips may be suitable for closure of iatrogenic mucosal defects without features of chronicity.

Endoscopic closure of acute esophageal perforations

Esophageal leak is a life-threatening problem that can result from spontaneous rupture of the esophagus, cancer, anastomotic dehiscence after surgery, or as a complication of endoscopy. During the last decade, developments in the minimally invasive endoluminal approach to the management of esophageal leaks include utilization of endoscopy not only for diagnosis but also for closure of leaks with clips or sutures, bypass of the leaks with stents, and/or endoluminal drainage of mediastinal infection. The aim of this review is to summarize recent advances and the principles of endoscopic management of acute esophageal perforations.

Benchtop testing and comparisons among three types of through-the-scope endoscopic clipping devices

BACKGROUND

Through-the-scope (TTS) endoscopic clipping devices are widely used. No benchtop testing or direct comparisons of these endoclips have been performed to show their rotational ability and inherent mechanical strengths during closure and after deployment. This study aimed to provide benchtop data that can be used to guide clinical applications and to promote future device research and development.

METHODS

Benchtop testing and comparisons were performed for three groups of TTS clips: QuickClip2 long, resolution, and instinct clips. The main outcome measurements were device-in-endoscope retroflection angles (DIERA), opening strength, "snapping" force of acute clip closure, and neoprene pulling strength.

RESULTS

The achievable gastroscope DIERA was 10° for QuickClip2, 3° for the resolution clip, and 10° for the instinct clip. The QuickClip and the Instinct clip rotated almost equally well under all endoscope configurations, including endoscopic retrograde cholangiopancreatography (ERCP). With or without a sheath, the resolution clip lacked the ability to rotate. During clip opening force testing (the amount of force required to force open the jaws of a deployed clip by 3.2 mm; 3.2 mm was chosen due to the standard dimension of the gauge used for the measurement), the Instinct clips were the strongest. For the Instinct clips, an opening force of 404 ± 124 g was needed to open the closed clip, and an additional 386 ± 133 g was required to open the clip jaws to 3.2 mm. In terms of snapping force during acute closure and neoprene pulling strength, the instinct and resolution clips performed almost equally. The limitations of the study were the benchtop testing and the finite sample size for closing and pulling strength comparisons.

CONCLUSIONS

The QuickClip2 and the Instinct clip rotate equally well under different endoscope configurations. The resolution clips lack rotational ability. The instinct clips are stronger mechanically than the other two TTS clips. Stronger clips are perhaps associated with higher therapeutic efficacy and retention rates.

Endoscopic therapy for severe ulcer bleeding

Upper gastrointestinal (UGI) bleeding secondary to ulcer disease occurs commonly and results in significant patient morbidity and medical expense. After initial resuscitation, carefully performed endoscopy provides an accurate diagnosis of the source of the UGI hemorrhage and can reliably identify those high-risk subgroups that may benefit most from endoscopic hemostasis. Effective endoscopic hemostasis of ulcer bleeding can significantly improve outcomes by reducing rebleeding, transfusion requirement, and need for surgery, as well as reduce the cost of medical care. This article discusses the important aspects of the diagnosis and treatment of bleeding from ulcers, with a focus on endoscopic therapy.

Therapeutic endoscopy for acute upper gastrointestinal bleeding

Endoscopy is the primary diagnostic and therapeutic tool for upper gastrointestinal bleeding (UGIB). The performance of endoscopic therapy depends on findings of stigmata of recent hemorrhage (SRH). For peptic ulcer disease-the most common etiology of UGIB-endoscopic therapy is indicated for findings of major SRH, such as active bleeding, oozing, or the presence of a nonbleeding visible vessel, but not indicated for minor SRH, such as a pigmented flat spot or a simple ulcer with a homogeneous clean base. Endoscopic therapies include injection, ablation, and mechanical therapy. Monotherapy reduces the risk of rebleeding in patients with peptic ulcer disease with major SRH to about 20%. Combination therapy, especially injection followed by either ablation or mechanical therapy, is generally recommended to further reduce the risk of rebleeding to about 10%. Endoscopic dual hemostasis by an experienced endoscopist reduces the risk of rebleeding, the need for surgery, the number of blood transfusions required, and the length of hospital stay. This Review article comprehensively analyzes the principles, indications, instrumentation, techniques, and efficacy of endoscopic hemostasis.