Endoluminal Probe Research Articles

Optical spectroscopy combined with high-resolution magnetic resonance imaging for digestive wall assessment: endoluminal bimodal probe conception and characterization in vitro, on organic sample and in vivo on a rabbit

Colorectal cancer is a major health issue worldwide. Conventional white light endoscopy (WLE) coupled to histology is considered as the gold standard today and is the most widespread technique used for colorectal cancer diagnosis. However, during the early stages, colorectal cancer is very often characterized by flat adenomas which develop just underneath the mucosal surface. The use of WLE, which is heavily based on the detection of morphological changes, becomes quite delicate due to subtle or quasi-invisible morphological changes of the colonic lining. Several techniques are currently being investigated in the scope of providing new tools that would allow such a diagnostic or assist actual techniques in so doing. We hereby present a novel technique where high spatial resolution MRI is combined with autofluorescence and reflectance spectroscopy in a bimodal endoluminal probe to extract morphological data and biochemical information, respectively. The design and conception of the endoluminal probe are detailed and the promising preliminary results obtained in vitro (home-built phantom containing eosin and rhodamine B), on an organic sample (the kiwi fruit) and in vivo on a rabbit are presented and discussed.

A novel endoesophageal magnetic device to prevent gastroesophageal reflux

Endoscopic methods to prevent gastroesophageal reflux (GER) show scarce effectiveness and may narrow the esophageal lumen more or less stiffly, sometimes impairing bolus transit and leading to dysphagia. The aim of this study was to demonstrate the possibility of reinforcing lower esophageal sphincter (LES) tone by implanting endoluminally a magnetic device. The device consists of two small magnetic plaques to be implanted in the submucosa close to LES with opposite polarities facing so that they attract one other, closing the esophageal lumen. The magnets were implanted by means of a special endoluminal device in five esophageal-gastric ex vivo specimens taken from swine. Variation in endoluminal pressure at the LES level was measured by means of slow pull-through of a thin side-hole manometric catheter in each specimen, before and after insertion of the magnets. The new high-pressure zone exhibited a length of about 2 cm and a pressure of 14.2+/-1.27 mmHg [mean +/- standard deviation (SD)], significantly (p<0.001) higher than that measured before insertion of the magnetic valve (1.5+/-0.26 mmHg). The present research demonstrates that it is possible to create at the LES level a dynamic closure of a value considered sufficient to prevent GER, by implanting in the esophageal submucosa of anatomical specimens a magnetic device by means of a special endoluminal probe. Once effectiveness and tolerability of magnets covered by a biocompatible sheath have been demonstrated in vivo, this device could become a simple and effective nonsurgical solution to GER.

Transvaginal interventional procedures: aspiration, biopsy, and catheter drainage.

Transvaginal ultrasonographically (US) guided procedures are simple and safe and often represent the only means of access to pelvic disease. Aspiration of cystic pelvic masses and core biopsy of solid pelvic masses can be easily performed by using the transvaginal route, an endoluminal US transducer, and a needle guide. Because of concerns about false-negative diagnosis and potential tumor seeding with biopsy of primary ovarian cystic lesions, the indications for transvaginal aspiration and biopsy of ovarian and adnexal lesions are predominantly therapeutic. Similarly, using an endoluminal probe with modification of the guide, one can also perform safe and effective trocar catheter drainage of pelvic abscesses via the transvaginal route. The transvaginal route is ideally suited to pelvic abscess drainage because of the proximity of the vaginal fornices to most pelvic fluid collections. The transvaginal route has the disadvantage of being semisterile; because of the risk of superinfecting previously noninfected pelvic pathologic conditions, the transvaginal approach should be used only for solid lesions or cystic lesions that can be completely aspirated. Familiarity with the transvaginal route of access is crucial for adequate treatment of many gynecologic and nongynecologic pelvic pathologic conditions.

3466 Performance of a miniature magnetic sensor for multidimensional imaging using 3d-eus and freehand scanning.

Background: A continuous pullback system is frequently used for acquisition of 3D-EUS images. However, free-hand systems have been used to obtain arbitrary volumes of data enabling flexible use of external ultrasound ( US ) probes. Aim: To test the performance in vitro and in vivo of a miniature magnetic sensor for endoluminal 3D-EUS. Methods: A miniature magnetic 6D position and orientation measurement system ( POM )( Mini-Bird TM ) was used to track different types of radial scanning endoluminal US probes. A precise six-degree of freedom digital position measurement table allowed a quantitative comparison of different probes and noisy influences from operating room environment.We used a non-ferric/non-magnetic endoscope ( MRI ), ( prototype MRI-endoscope, GF-MR30C, Olympus Co., Tokyo Japan ), with or without 12- ( UM2R ) and 20MHz ( UM3R ) miniature radial scanning US probes or an echoendoscope ( GFUM ). The performance is presented as mean difference between test values and control ( mm ± 2SD ), expressed as relative values, and/or correlation coefficients ( r ). 3D-EUS image reconstruction was evaluated on phantoms in vitro and finally in esophagus or stomach in anestesized pigs using frame-grabbed video images. Results: The receiver could be mounted on the endoscope tip or US scanheads. The 6D position an orientation measurement system allowed very good correlation (r=0,99), and was able to locate points with high accuracy (0,75 ± 2,60 mm), compared to absolute positions, over its specified operating range of 50 cm. The POM system was rather insensitive to errors resulting from eddy currents in conducting materials and interference from medical equipment near the receiver, typical 0,09 ± 0,20 mm, r=1,0. The relative performance when the POM was combined with different endoluminal probes was, UM2R (0,20 ± 0,42 mm, r=0,99), UM3R (0,20 ± 0,50 mm, r=0,99), MRI (0,85 ± 1,10 mm, r=0,99), GFUM (1.80 ± 1,88 mm, r=99. Software reconstruction based on free hand EUS scanning and POM registration resulted in accurate 3D-EUS images of the phantoms, gastrointestinal wall and adjacent structures that could be evaluated in a multiplane fashion. Conclusions: The performance of the POM system was similar if ferric or non-ferric probes were used for radial scanning EUS. 3D-EUS image reconstruction could be performed using free hand scanning in vitro and in animal organs. Combination of 3DEUS/POM registration may enable better description of true topographic relations and accurate volume measurements using 3D-EUS.

The phlebectomy probe: a new and useful instrument for ambulatory phlebectomy.

Tethering of varicose veins by periadventitial connective tissue can limit the length of vein segment that can be avulsed during ambulatory phlebectomy. A thin, malleable blunt probe is described which can dissect connective tissue adhesions surrounding varicose veins. This probe can be used as an endoluminal probe to localize elusive veins. We describe the use of a new type of phlebectomy probe for periadventitial dissection and endoluminal probing during ambulatory phlebectomy. The techniques of periadventitial dissection and endoluminal probing are reviewed. The phlebectomy probe seems to permit extraction of longer segments of varicose veins after releasing periadventitial adhesions. Endoluminal probing can assist in difficult localization of venous segments. The phlebectomy probe can be helpful for releasing periadventitial adhesions that tether varicose veins. Its application is simple and can result in increased length of avulsed varicose vein segments, thereby reducing the number of incisions needed.

Sigmoidal ischaemia after aortic grafting, detected by endoluminal pulse oximetry

Colonic ischaemia after abdominal aortic grafting is a severe complication. Late detection of transmural ischaemia will result in a high mortality rate. No simple specific methods are available to detect the early stage. The aim of this pilot study was to detect and monitor sigmoidal ischaemia after aortic surgery with a new endoluminal slgmoidal probe, based on pulse oximetry. Twelve patients with sigmoidal ischaemia were included, the endoluminal probe being introduced into the sigmoid at least 25 cm proximal to the anal verge. It is shown that with this method, mucosal and transmural ischaemia can be graded and differentiated. Patients who showed no wave-form had transmural ischaemia; those with mucosal ischaemia showed reliable wave-forms with oxygen saturation from 40–85%. Colonic ischaemia after aortic grafting can be detected by endoluminal pulse oximetry but the clinical outcome will only improve by early detection in the preclinical stage.

Sigmoidal Ischaemia after Aortic Grafting, Detected by Endoluminal Pulse Oximetry

Colonic ischaemia after abdominal aortic grafting is a severe complication. Late detection of transmural ischaemia will result in a high mortality rate. No simple specific methods are available to detect the early stage. The aim of this pilot study was to detect and monitor sigmoidal ischaemia after aortic surgery with a new endoluminal sigmoidal probe, based on pulse oximetry. Twelve patients with sigmoidal ischaemia were included, the endoluminal probe being introduced into the sigmoid at least 25 cm proximal to the anal verge. It is shown that with this method mucosal and transmural ischaemia can be graded and differentiated. Patients who showed no wave-form had transmural ischaemia; those with mucosal ischaemia showed reliable wave-forms with oxygen saturation from 40–85%. Colonic ischaemia after aortic grafting can be detected bv endoluminal pulse oximetry but the clinical outcome will only improve by early detection in the preclinical stage. Copyright © 1996 The International Society for Cardiovasular Surgery.

Sennosides and human colonic motility.

The effects of stimulant laxatives on colonic motility in man still remain controversial. Stimulation of peristalsis or a decrease of intraluminal pressure has been described manometrically after intraluminal administration of laxatives including senna. In contrast to manometry, electromyographic methods using an endoluminal probe enable continuous colonic motor recordings over a long colonic segment for at least 24 h, and consequently studies following the course of laxative effects after oral administration, the classical therapeutic route, are possible. Preliminary results using sennosides obtained with few subjects provide evidence for an increase in propulsive activity expressed as an increased number of migrating long-spike bursts in the left and sigmoid human colon. This motor colonic pattern seems to be a common feature in nonspecific or induced diarrhoea.