The Future Is Wireless: Advances in Wireless Diagnostic and Therapeutic Technologies in Gastroenterology
2009; Elsevier BV; Volume: 137; Issue: 2 Linguagem: Inglês
10.1053/j.gastro.2009.06.029
ISSN1528-0012
Autores Tópico(s)Gastrointestinal motility and disorders
ResumoArthur C. Clarke in his essay “Hazards of Prophecy: The Failure of Imagination,” proposed 3 laws of prediction. The first law is that, “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.” Others are not so forward thinking when it comes to embracing innovation. “The wireless music box has no imaginable commercial value. Who would pay for a message sent to nobody in particular?” were the comments of David Sarnoff's associates in response to his urgings for investment in the radio in the 1920s. Although the associate was probably neither elderly nor a scientist, he was almost certainly in good company at the time. Skepticism about new technologies has existed in all walks of life and at all stages of history. Yet, every day new technologies come online and affect every sphere of our lives, including medicine.Advances in wireless technologies have tremendously enhanced diagnostic and therapeutic capabilities in gastroenterology and have improved our ability to take care of our patients. Furthermore, they have allowed patients the freedom to not be physically tied to their physician or the testing facility, and have testing performed in the comfort of their home. As gastroenterologists, advances in wireless technologies are allowing us to perform gastrointestinal (GI) diagnostic procedures with increased patient comfort, and to look and treat deeper in the GI tract, beyond the reach of traditional wired devices and endoscopes. There are great advances being made in wireless diagnostic and therapeutic technologies in gastroenterology. This article gives an overview of the advances that will significantly impact the specialty of gastroenterology in the near future.Wireless Diagnostic TechnologiesBravo pH TestingEsophageal pH testing have been the gold standard for diagnosing gastroesophageal reflux disease (GERD); however, the test has been underutilized because of patient discomfort associated with the traditional nasopharyngeal wired pH monitoring system. The Bravo pH capsule (GIVEN Imaging, Atlanta, GA) is a wireless, radio-telemetry–based, intra-esophageal pH monitoring system that eliminates the discomfort of an indwelling nasopharyngeal catheter. The Bravo pH capsule measures 25 × 6 × 5.5 mm and is placed either transorally or transnasally with or without sedation after either endoscopic or manometric localization of the lower esophageal sphincter (LES). The pH capsule consists of a battery, radio transmitter, and an antimony pH electrode at its distal tip to measure esophageal pH. The pH electrode samples esophageal pH every 6 seconds and data are transmitted every 12 seconds for 48 hours to an external receiver unit worn by the patient.1Pandolfino J.E. Schreiner M.A. Lee T.J. et al.Comparison of the Bravo wireless and Digitrapper catheter-based pH monitoring systems for measuring esophageal acid exposure.Am J Gastroenterol. 2005; 100: 1466-1476Crossref PubMed Scopus (81) Google Scholar A composite pH score of >14 on any of the two 24-hour recordings has a high sensitivity, specificity, and positive and negative predictive values, and an accuracy of 95%.2Ayazi S. Lipham J.C. Portale G. et al.Bravo catheter-free pH monitoring: normal values, concordance, optimal diagnostic thresholds, and accuracy.Clin Gastroenterol Hepatol. 2009; 7: 60-67Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar The bravo pH capsule is significantly better tolerated by the patients and allows pH monitoring under more physiologic conditions, improving the accuracy of the test in detecting GERD. The Bravo pH capsule is primarily used to establish the diagnosis of GERD in patients with atypical symptom, symptoms not responding to medication, or conclusively establish the diagnosis before anti-reflux surgery. The Bravo pH testing should ideally be performed while the patient is off antisecretory medications.Wireless pH/Impedance TestingMultichannel intraluminal impedance testing has gained significant interest and clinical acceptance for the diagnosis of weakly acidic or non-acid reflux. Current impedance pH testing systems use nasopharyngeal catheters to measure changes in esophageal impedance (conductivity across 2 closely spaced electrodes) owing to intraesophageal refluxate or food bolus. The system uses directionality (anterograde indicating a swallow and retrograde indicating a reflux event) of the impedance change to diagnose a swallow or a reflux event. Additional pH sensors on the impedance catheter are used to assess the pH of the refluxate. Recently, a wireless, impedance-based pH monitoring system has been developed. The battery-less system uses inductive links between 2 coils. An external coil forms a resonance circuit with a radiofrequency source worn externally by the patient and a small coil with inter-digitated electrodes implanted in the esophagus to detect changes in esophageal impedance. The impedance changes in the esophagus, caused by fluid passing, can be detected by either amplitude or frequency modulation. The system in vitro and in vivo has been shown to measure pH accurately using impedance changes and may be better tolerated than the current catheter-based impedance system.3Hsu L. Tang S. Huang W. et al.An implantable, batteryless and wireless capsule with integrated impedance and pH sensors for detecting the reflux of acidic and non-acidic materials.Gastroenterology. 2009; 136: W1080Google Scholar Impedance testing is primarily used to establish the etiology of symptoms not responding to antisecretory medication or to detect reflux of non-acidic content as a source of patient's symptoms. The impedance/pH testing is ideally performed on maximal antisecretory therapy.Wireless Whole Gut Pressure and pH Monitoring SystemThis Smart Pill system (SmartPill Corporation, MotiliGI, Buffalo, NY) consists of a wireless motility capsule, data receiver, docking station, computer, and data analysis software. The shape and dimensions of the Smart Pill capsule (cylindrical, 26.8 mm long × 11.7 mm in diameter) are similar to the video capsule endoscopes. The capsule houses sensors for pH, temperature, and pressure and wirelessly transmits this information at 434 MHz using RF-technology. The capsule measures pH (range, 0.05–9.0 pH units) with an accuracy of ±0.5 pH units, pressure (range, 0–350 mmHg) with an accuracy of ±5 mmHg and temperature (range, 25–49°C) with an accuracy of ±1°C. The data receiver is powered by rechargeable batteries. After completion of study, the data are downloaded to a Windows PC-compatible laptop and data are analyzed. The initial studies reveal promising results in determining the gastric and whole gut transit using the Smart Pill. However, the clinical utility of various physiologic parameters throughout the GI tract and their alteration in various disease states need to be further elucidated. SmartPill is approved by the US Food and Drug Administration (FDA) for the measurement of gastric emptying in patients with suspected gastroparesis.4Rao S.S. Kuo B. McCallum R.W. et al.Investigation of colonic and whole-gut transit with wireless motility capsule and radiopaque markers in constipation.Clin Gastroenterol Hepatol. 2009; 7: 537-544Abstract Full Text Full Text PDF PubMed Scopus (248) Google Scholar Another novel ingestible event marker system (Proteus, CA) has been recently reported to measure physiologic transit times with high detection accuracy. The ingestible event marker system offers promise of a new physiologic monitoring system; however, its clinical utility in gastroenterology remains to be established.5Epstein M. Ingestible event marker system- a novel physiologically-sized device platform for frequent, repeated use.Gastrointest Endosc. 2009; 69 (AB 106)Abstract Full Text Full Text PDF Google ScholarWireless GI ImagingGI endoscopy has been the mainstay of GI diagnostics and therapeutics. A major paradigm shift in GI endoscopy happened with the advent of wireless GI imaging using capsule endoscopes. The capsule endoscopy system consists of an ingestible capsule, a data recorder, and a computer work station to download and analyze the capsule images. The small bowel capsule endoscope measures 11 × 24–26 mm in dimension, weigh around 3.4 g, and obtain 2–3 images per second. There are 5 capsule endoscopy systems available: PillCam (GIVEN Imaging), EndoCapsule (Olympus, Center Valley, PA), MiroCam (Intromedic, Seoul, Korea), OmOm capsule (Jinshan Science and Technology, Chongqing, China), and Sayaka (RF System Labs, Nagano, Japan); however, only the PillCam and EndoCapsule are currently FDA approved for use in the United States. PillCam uses a complimentary oxide silicone chip and EndoCapsule uses a charge couple device chip for imaging. Both these capsule endoscopes use RF-based communication technology. MiroCam is currently undergoing FDA approval trials in the United States and uses a complimentary oxide silicone chip for imaging and the Human Body Communication technology for transmission of images. Human Body Communication technology uses 2 external capsule electrodes to transmit and a single skin electrode to receive the data using the human body as an electrical conductor. This methodology uses less energy, allowing the capsule to obtain images at higher frame rate (3 images per second) and for a longer duration (11 hours) compared with other capsule endoscopy systems. Preliminary data from OmOm capsule suggests that the OmOm capsule has comparable test characteristics to the other 3 capsule endoscopes. In addition, GIVEN imaging has an FDA-approved esophageal capsule endoscope PillCam ESO for the evaluation of esophageal disease such as Barrett's esophagus and esophageal varices and a colon capsule endoscope PillCam Colon that is undergoing FDA trials in the United States for the evaluation of various colonic diseases. Both the esophageal and colon capsule endoscopes have cameras at both ends. The esophageal capsule endoscope acquires images at 7–9 fps/camera per second and the colon capsule endoscope acquires images 2 fps/camera per second.6Swain P. The future of wireless capsule endoscopy.World J Gastroenterol. 2008; 14: 4142-4145Crossref PubMed Scopus (133) Google ScholarThe future advances in capsule endoscopy system will improve the efficiency and diagnostic capabilities of these endoscopes, and offer opportunities for therapy. Externally rechargeable batteries using RF, microwave, ultrasound, or electric induction technology will eliminate battery life constraints and make prolonged capsule endoscopy, including tethered capsule endoscopy, possible. Sayaka (RF System Labs) is a new, “battery-free” capsule endoscope that uses induction charging to draw power. The camera is mounted on the side as opposed to the end of the capsule. The camera rotates along the long access of the capsule taking 30 en face images per second over the entire inner surface of the entire GI tract. The captured images are transmitted to the receiver and then processed into an extensive series of overlapped “mosaicing” images. These “mosaic” images are created to replicate a 6- to 8-meter-long digestive canal. The result is a pipe shaped tract that can be stored in a long and continuous form and can be “dissected” to view in long form. Any area of interest can also be magnified up to 75 times on the screen for detailed viewing.7RF System Lab. Sayakahttp://www.rfamerica.com/sayaka/index.htmlGoogle Scholar Check cap is developing an imaging capsule aiming to provide a 3-dimensional (3D) reconstruction of the colon without the need to clean the bowel. This imaging capsule contains a tiny, sonar-like device that transmits x-rays with minimal radiation (the equivalent of a chest x-ray, or 1/300 of a computed tomographic colography), to the intestinal wall, which are reflected back and captured by the imaging capsule. The analysis of distances creates 3D images of the colon's internal surface, enabling the detection of clinically significant polyps (Figure 1). Because x-rays, unlike optic alternatives, can “see through” colon content and are transmitted a full 360°radius around the capsule, bowel cleansing is unnecessary and colonic folds do not obstruct the view. The imaging capsule travels painlessly through the colon, and is excreted naturally. A gastroenterologist analyzes the data that's been transmitted to a waist- or wrist-worn receiver; a colonoscopy is needed if polyps are detected.In addition, improvement in the chip technology and emergence of hybrid imaging chips will further improve image resolution and will capture more image information for digital image analysis of normal and pathology. Blue light imaging including recent integration of the Fuji Intelligent Chromo Endoscopy (FICE) with PillCam capsule endoscopy system, optical biopsies, and chemical or immunologic tagging and imaging of pathology will further improve disease recognition. The Nano-based capsule-Endoscopy with Molecular Imaging and Optical biopsy (NEMO) project is a consortium of industry and academic institutions that plan to develop a new capsule endoscopy system that will combine optical and nano technologies, biosensing, and maneuvering technologies to create a unique capsule endoscope capable of secretion analysis and detection of marked and deep tissue diseases. The consortium predicts that the fusion of optical images with data from molecular analysis may provide a novel and effective device for mass screening for GI cancer. In addition, advanced wireless imaging with capsule technology will improve wireless laparoscopy and NOTES applications.Future improvements in the battery technology using carbon nanotubes and Bucky tubes will reduce the size and improve the efficiency of batteries that occupy the most space in a capsule endoscope, thus freeing up space for additional diagnostic and therapeutic component.Pilot data from centers developing diagnostic and therapeutic capsules have demonstrated the feasibility studies of performing mucosal biopsies using a spring loaded Crosby capsule type device guided by real-time imaging capability and RF-controlled remote manipulation. Other biopsy devices that have been successfully demonstrated in animal modes include a capsule with a single-crystal silicon planar microspikes with protruding barbs for microscale biopsy that utilizes Micro-Electro-Mechanical Systems (MEMS) technology. Other capsules have used a rotational microbiopsy device consisting of a trigger with a paraffin block, rotational tissue-cutting razor with a torsion controller designed to operate sequentially so that the tissue sampling, sealing, and fixing are achieved in single operation8Kong K. Cha J. Jeon D. et al.A rotational micro biopsy device for the capsule endoscope Intelligent Robots and Systems, 2005. (IROS 2005).in: 2005: 1839-1843http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1545441&isnumber=32977Google Scholar (Figure 2). Prototype coagulation capsules are being tested. In addition, the feasibility of manipulating the capsule endoscope or creating a locomotion or propulsion mechanism using external magnets, electrostimulation, hydrojets, shape memory alloy coils, and MEMS-based modular actuators have already been demonstrated.9Menciassi A. Stefanini C. Gorini S. et al.Legged locomotion in the gastrointestinal tract.in: 2004: 937-942Google Scholar The Versatile Endoscopic Capsule for gastrointestinal TumOr Recognition and therapy (VECTOR) project, funded by European Commission, is developing a minirobot endowed with actuation modules, mechanisms, sensors, embedded controls, and human–machine interface with the task to navigate and intervene in the GI tract for early detection of GI cancer (Figure 3).Figure 2Prototype Rotational Micro Biopsy Capsule Device. (Courtesy Prof. Doyoung Jeon, Department of Mechanical Engineering, Sogang University, Seoul, Korea.)View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 3Vision of VECTOR Capsule with different diagnostic and therapeutic capabilities.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Researchers at the City University and City College of New York have developed a video capsule endoscope called Compact Photonic Explorer (CPE), with the capability to externally manipulate the capsule by remote controlled radio signal and computer software. The CPE measures 5 mm, and includes a transport capsule that contains imaging, data transmission, and collection capabilities. The CPE can detect disease and monitor bodily functions by combining imaging, polarization, spectroscopy, fluorescence, and biosensor technologies. The investigators claim that in the future CPE will be able to perform therapies like laser tissue removal and tissue welding at precise locations within the intestinal tract. Olympus has announced that they have developed wireless power supply, fluid sampling capabilities, remote manipulation, drug delivery capabilities, and ultrasound capabilities in their capsule endoscopes.Engineering-Based Capsule for Targeted Drug DeliveryMultiple wireless capsules have been developed for targeted drug delivery for better understanding the pharmacokinetics of various new drugs. However, the same technology can be used to deliver the drug or therapeutic agent to a specific area of the GI tract, thereby reducing the dose of the drug administered and associated side effects. The high-frequency capsule (Battelle-Institute V, Frankfurt am-Maine, Germany) uses an external RF trigger to melt a thread, thus releasing a needle that pierces a balloon and delivers a therapeutic agent at a specific site. The location of the capsule is monitored using fluoroscopy, which tends to be inaccurate and may expose the patient to excessive radiation. The Gastrotarget telemetric capsule (Gastrotarget, Tonawanda, NY) and Telemetric capsule (INSERM U61, Strasbourg Cedex, France) use RF signal and complex localization algorithms to deliver the drug in a specific area of the GI tract. Recently, IntelliSite Capsule (Innovative Devices, Raleigh, NC) and Enterion Capsule (Pheaton Research, Nottingham, UK) have become popular tools for collecting absorption data in GI tract and can also be used for targeted drug delivery.10Wilding I. Hirst P. Connor A. Development of a new engineering-based capsule for human drug absorption studies.Pharmaceutical Science & Technology Today. 2000; 11: 385-392Crossref Scopus (121) Google Scholar iPill (Philips Research, Eindhoven, The Netherlands) is a prototype capsule that measures 11 × 26 mm and incorporates a microprocessor, battery, pH sensor, temperature sensor, RF wireless transceiver, fluid pump, and drug reservoir (Figure 4). The RF wireless transceiver is used to communicate with a control unit outside the body. Using the information on pH change measured by the iPill, and data about gut transit times, the iPill's location in the gut can be determined with fair accuracy. Targeted drug delivery is performed by the iPill's internal pump under the control of the microprocessor, allowing accurate control of the drug delivery profiles such as a burst, progressive release, or a multi-location dosing. The iPill drug delivery system is currently being evaluated in patients with Crohn's disease and colon cancer.11Philips TechnologyPhilips intelligent pill technology.http://www.research.philips.com/newscenter/backgrounders/081111-ipill.htmlGoogle ScholarFigure 4Philips Research's intelligent pill (iPill) for electronically controlled drug delivery. The iPill is an 11- × 26-mm capsule that incorporates a microprocessor, battery, pH sensor, temperature sensor, RF wireless transceiver, fluid pump, and drug reservoir.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Implantable MicrostimulatorThe GI tract is a complex neuromuscular organ and various devices are being developed for GI neurostimulation to treat a host of GI neuromuscular or motility disorders such as gastroparesis, obesity, and GERD. Investigators from The Johns Hopkins University School of Medicine have demonstrated the feasibility of the Bion (Advanced Bionics Corporation, Valencia, CA) a self-contained, battery-powered, remotely programmable, micro-stimulator (7 g; 3.3 × 27 mm; Figure 5) in raising the LES pressure in both porcine and canine models. In the canine study, the micro-stimulator was endoscopically implanted into the LES. The micro-stimulator was remotely turned on resulting in a dose-dependent increase in the LES pressure in all the dogs. The authors concluded that this minimally invasive procedure may be a novel approach to treatment of GERD and other GI motility disorders.12Clarke J.O. Jagannath S.B. Kalloo A.N. et al.An endoscopically implantable device stimulates the lower esophageal sphincter on demand by remote control: a study using a canine model.Endoscopy. 2007; 39: 72-76Crossref PubMed Scopus (29) Google ScholarFigure 5Bion MicroStimulator (27 mm long × 3.3 mm in diameter).View Large Image Figure ViewerDownload Hi-res image Download (PPT)ConclusionMultiple advances in wireless technology are on the horizon and will significantly affect diagnostic and therapeutic gastroenterology and endoscopy. These advances will allow us to look deeper, see better, and measure more physiologic parameters in the GI tract. In addition, wireless technologies will help us to target and treat GI disease with minimal invasiveness, and improved patient safety and comfort. In the words of Sir Arthur C. Clarke, in his second law of prediction, “the only way of discovering the limits of the possible is to venture a little way past them into the impossible”; we are headed in that direction, wirelessly. If Clarke's third law of prediction—that “any sufficiently advanced technology is indistinguishable from magic”—is any guide, achieving what was previously impossible ought to make patients and gastroenterologists alike feel excited about our wireless future. Arthur C. Clarke in his essay “Hazards of Prophecy: The Failure of Imagination,” proposed 3 laws of prediction. The first law is that, “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.” Others are not so forward thinking when it comes to embracing innovation. “The wireless music box has no imaginable commercial value. Who would pay for a message sent to nobody in particular?” were the comments of David Sarnoff's associates in response to his urgings for investment in the radio in the 1920s. Although the associate was probably neither elderly nor a scientist, he was almost certainly in good company at the time. Skepticism about new technologies has existed in all walks of life and at all stages of history. Yet, every day new technologies come online and affect every sphere of our lives, including medicine. Advances in wireless technologies have tremendously enhanced diagnostic and therapeutic capabilities in gastroenterology and have improved our ability to take care of our patients. Furthermore, they have allowed patients the freedom to not be physically tied to their physician or the testing facility, and have testing performed in the comfort of their home. As gastroenterologists, advances in wireless technologies are allowing us to perform gastrointestinal (GI) diagnostic procedures with increased patient comfort, and to look and treat deeper in the GI tract, beyond the reach of traditional wired devices and endoscopes. There are great advances being made in wireless diagnostic and therapeutic technologies in gastroenterology. This article gives an overview of the advances that will significantly impact the specialty of gastroenterology in the near future. Wireless Diagnostic TechnologiesBravo pH TestingEsophageal pH testing have been the gold standard for diagnosing gastroesophageal reflux disease (GERD); however, the test has been underutilized because of patient discomfort associated with the traditional nasopharyngeal wired pH monitoring system. The Bravo pH capsule (GIVEN Imaging, Atlanta, GA) is a wireless, radio-telemetry–based, intra-esophageal pH monitoring system that eliminates the discomfort of an indwelling nasopharyngeal catheter. The Bravo pH capsule measures 25 × 6 × 5.5 mm and is placed either transorally or transnasally with or without sedation after either endoscopic or manometric localization of the lower esophageal sphincter (LES). The pH capsule consists of a battery, radio transmitter, and an antimony pH electrode at its distal tip to measure esophageal pH. The pH electrode samples esophageal pH every 6 seconds and data are transmitted every 12 seconds for 48 hours to an external receiver unit worn by the patient.1Pandolfino J.E. Schreiner M.A. Lee T.J. et al.Comparison of the Bravo wireless and Digitrapper catheter-based pH monitoring systems for measuring esophageal acid exposure.Am J Gastroenterol. 2005; 100: 1466-1476Crossref PubMed Scopus (81) Google Scholar A composite pH score of >14 on any of the two 24-hour recordings has a high sensitivity, specificity, and positive and negative predictive values, and an accuracy of 95%.2Ayazi S. Lipham J.C. Portale G. et al.Bravo catheter-free pH monitoring: normal values, concordance, optimal diagnostic thresholds, and accuracy.Clin Gastroenterol Hepatol. 2009; 7: 60-67Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar The bravo pH capsule is significantly better tolerated by the patients and allows pH monitoring under more physiologic conditions, improving the accuracy of the test in detecting GERD. The Bravo pH capsule is primarily used to establish the diagnosis of GERD in patients with atypical symptom, symptoms not responding to medication, or conclusively establish the diagnosis before anti-reflux surgery. The Bravo pH testing should ideally be performed while the patient is off antisecretory medications.Wireless pH/Impedance TestingMultichannel intraluminal impedance testing has gained significant interest and clinical acceptance for the diagnosis of weakly acidic or non-acid reflux. Current impedance pH testing systems use nasopharyngeal catheters to measure changes in esophageal impedance (conductivity across 2 closely spaced electrodes) owing to intraesophageal refluxate or food bolus. The system uses directionality (anterograde indicating a swallow and retrograde indicating a reflux event) of the impedance change to diagnose a swallow or a reflux event. Additional pH sensors on the impedance catheter are used to assess the pH of the refluxate. Recently, a wireless, impedance-based pH monitoring system has been developed. The battery-less system uses inductive links between 2 coils. An external coil forms a resonance circuit with a radiofrequency source worn externally by the patient and a small coil with inter-digitated electrodes implanted in the esophagus to detect changes in esophageal impedance. The impedance changes in the esophagus, caused by fluid passing, can be detected by either amplitude or frequency modulation. The system in vitro and in vivo has been shown to measure pH accurately using impedance changes and may be better tolerated than the current catheter-based impedance system.3Hsu L. Tang S. Huang W. et al.An implantable, batteryless and wireless capsule with integrated impedance and pH sensors for detecting the reflux of acidic and non-acidic materials.Gastroenterology. 2009; 136: W1080Google Scholar Impedance testing is primarily used to establish the etiology of symptoms not responding to antisecretory medication or to detect reflux of non-acidic content as a source of patient's symptoms. The impedance/pH testing is ideally performed on maximal antisecretory therapy.Wireless Whole Gut Pressure and pH Monitoring SystemThis Smart Pill system (SmartPill Corporation, MotiliGI, Buffalo, NY) consists of a wireless motility capsule, data receiver, docking station, computer, and data analysis software. The shape and dimensions of the Smart Pill capsule (cylindrical, 26.8 mm long × 11.7 mm in diameter) are similar to the video capsule endoscopes. The capsule houses sensors for pH, temperature, and pressure and wirelessly transmits this information at 434 MHz using RF-technology. The capsule measures pH (range, 0.05–9.0 pH units) with an accuracy of ±0.5 pH units, pressure (range, 0–350 mmHg) with an accuracy of ±5 mmHg and temperature (range, 25–49°C) with an accuracy of ±1°C. The data receiver is powered by rechargeable batteries. After completion of study, the data are downloaded to a Windows PC-compatible laptop and data are analyzed. The initial studies reveal promising results in determining the gastric and whole gut transit using the Smart Pill. However, the clinical utility of various physiologic parameters throughout the GI tract and their alteration in various disease states need to be further elucidated. SmartPill is approved by the US Food and Drug Administration (FDA) for the measurement of gastric emptying in patients with suspected gastroparesis.4Rao S.S. Kuo B. McCallum R.W. et al.Investigation of colonic and whole-gut transit with wireless mo
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