Integrated optical tools for minimally invasive diagnosis and treatment at gastrointestinal endoscopy

Article · April 2011with15 Reads
DOI: 10.1016/j.rcim.2010.06.006
Over the past two decades, the bulk of gastrointestinal (GI) endoscopic procedures has shifted away from diagnostic and therapeutic interventions for symptomatic disease toward cancer prevention in asymptomatic patients. This shift has resulted largely from a decrease in the incidence of peptic ulcer disease in the era of antisecretory medications coupled with emerging evidence for the efficacy of endoscopic detection and eradication of dysplasia, a histopathological biomarker widely accepted as a precursor to cancer. This shift has been accompanied by a drive toward minimally invasive, in situ optical diagnostic technologies that help to assess the mucosa for cellular changes that relate to dysplasia. Two competing but complementary approaches have been pursued. The first approach is based on broad-view targeting of “areas of interest” or “red flags”. These broad-view technologies include standard white light endoscopy (WLE), high-definition endoscopy (HD), and “electronic” chromoendoscopy (narrow-band-type imaging). The second approach is based on multiple small area or point-source (meso/micro) measurements, which can be either machine (spectroscopy) or human-interpreted (endomicroscopy, magnification endoscopy), much as histopatholgy slides are. In this paper we present our experience with the development and testing of a set of familiar but “smarter” standard tissue-sampling tools that can be routinely employed during screening/surveillance endoscopy. These tools have been designed to incorporate fiberoptic probes that can mediate spectroscopy or endomicroscopy. We demonstrate the value of such tools by assessing their preliminary performance from several ongoing clinical studies. Our results have shown promise for a new generation of integrated optical tools for a variety of screening/surveillance applications during GI endoscopy. Integrated devices should prove invaluable for dysplasia surveillance strategies that currently result in large numbers of benign biopsies, which are of little clinical consequence, including screening for colorectal polyps and surveillance of “flat” dysplasia such as Barrett’s esophagus and chronic colitis due to inflammatory bowel diseases.
    • "Elastic scatter spectroscopy (ESS) is related to optical scattering efficiency caused by optical index gradients of cellular and subcellular structures, allowing for detailed evaluation of microstructural features such as nuclear size, crowding and chromaticity, chromatin granularity, and mitochondrial and organellar size and density [97] . This technique has shown promise in preliminary studies, notably decreasing the number of biopsies required to diagnose dysplasia compared to the Seattle protocol [98] , but more prospective data is needed. "
    [Show abstract] [Hide abstract] ABSTRACT: Due to its rapidly rising incidence and high mortality, esophageal adenocarcinoma is a major public health concern, particularly in Western countries. The steps involved in the progression from its predisposing condition, gastroesophageal reflux disease, to its premalignant disorder, Barrett's esophagus, and to cancer, are incompletely understood. Current screening and surveillance methods are limited by the lack of population-wide utility, incomplete sampling of standard biopsies, and subjectivity of evaluation. Advances in endoscopic ablation have raised the hope of effective therapy for eradication of high-risk Barrett's lesions, but improvements are needed in determining when to apply this treatment and how to follow patients clinically. Researchers have evaluated numerous potential molecular biomarkers with the goal of detecting dysplasia, with varying degrees of success. The combination of biomarker panels with epidemiologic risk factors to yield clinical risk scoring systems is promising. New approaches to sample tissue may also be combined with these biomarkers for less invasive screening and surveillance. The development of novel endoscopic imaging tools in recent years has the potential to markedly improve detection of small foci of dysplasia in vivo. Current and future efforts will aim to determine the combination of markers and imaging modalities that will most effectively improve the rate of early detection of high-risk lesions in Barrett's esophagus.
    Full-text · Article · Nov 2014
    • "previously mentioned, the competing requirements for a strong optical signal versus a small FNA needle presented the largest design challenge for the prototype probe. Standard ESS probes, used in other clinical studies, incorporated two 200 lm core fibers (240 lm total diameter) within a plastic housing with an outer diameter of up to 2.5 mm [8,28,30,39,40]. A standard 25 gauge FNAB needle has a specified inner diameter (ID) of 240 lm, so the previously used ESS probes would not fit. "
    [Show abstract] [Hide abstract] ABSTRACT: Thyroid nodules are a frequent clinical finding and the most common endocrine malignancy is thyroid cancer. The standard of care in the management of a patient with a thyroid nodule is to perform a preoperative fine needle aspiration (FNA) biopsy of the suspect nodule under ultrasound imaging guidance. In a significant percentage of the cases, cytological assessment of the biopsy material yields indeterminate results, the consequence of which is diagnostic thyroidectomy. Unfortunately, 75-80% of diagnostic thyroidectomies following indeterminate cytology result in benign designation by post-surgery histopathology, indicating potentially unnecessary surgeries. Clearly, the potential exists for the improvement in patient care and the reduction of overall procedure costs if an improved preoperative diagnostic technique was developed. Elastic scattering spectroscopy (ESS) is an optical biopsy technique that is mediated by optical fiber probes and has been shown to be effective in differentiating benign from malignant thyroid tissue in ex vivo surgical tissue samples. The goal of the current research was to integrate the ESS fiber optic probes into a device that can also collect cells for cytological assessment and, thus, enable concurrent spectroscopic interrogation and biopsy of a suspect nodule with a single needle penetration. The primary challenges to designing the device included miniaturizing the standard ESS fiber optic probe to fit within an FNA needle and maintaining the needle's aspiration functionality. We demonstrate the value of the fabricated prototype devices by assessing their preliminary performance in an on-going clinical study with >120 patients. The devices have proven to be clinically friendly, collecting both aspirated cells and optical data from the same location in thyroid nodules and with minimal disruption of clinical procedure. In the future, such integrated devices could be used to complement FNA-based cytological results and have the potential to both reduce the number of diagnostic thyroidectomies on benign nodules and improve the surgical approach for patients with thyroid malignancies, thereby, decreasing healthcare costs and improving patient outcomes.
    Full-text · Article · Jun 2014
  • [Show abstract] [Hide abstract] ABSTRACT: AIM: To study the impact of Helicobacter pylori (H.pylori) infection and other risk factors on the development of gastric ulcer (GU) and duodenal ulcer (DU). METHODS: A total of 204 patients who were treated at our hospital from 2003 to 2008 were included. The association of H.pylori infection status ( 14C-UBT), endoscopic findings, personal habits (smoking, alcohol intake), and medication (non-steroidal anti-inflammatory drugs (NSAIDs), aspirin intake) with the development of GU and DU was investigated using multiway frequency analysis. RESULTS: GU in the presence of H.pylori had significant association with aspirin (P = 0.0010), alcohol (P = 0.0091) and NSAIDs (P = 0.0321). DU in the presence of H.pylori had significant association with aspirin/smoking/NSAIDs (P = 0.0256), aspirin/alcohol (P = 0.0020) and aspirin/ smoking (P = 0.0221). In the absence of H.pylori, GU had significant association with alcohol/NSAIDs (P = 0.0435) and NSAIDs (P = 0.0431), while DU had significant association with smoking/alcohol/NSAIDs (P = 0.0014), aspirin/ NSAIDs (P = 0.0331), and aspirin/alcohol (P = 0.0032). CONCLUSION: In the presence of H.pylori, intake of aspirin, alcohol or NSAIDs acts as independent risk factors for the occurrence of GU but affects the occurrence of DU only when combined together.
    Article · Jan 2011
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