Michael D. Rice

Characterizing intestinal inflammation and fibrosis in Crohn's disease by photoacoustic imaging: feasibility study.

The pathology of Crohns disease (CD) is characterized by obstructing intestinal strictures because of inflammation (with high levels of hemoglobin), fibrosis (high levels of collagen), or a combination of both. The accurate characterization of the strictures is critical for the management of CD. This study examines the feasibility of characterizing intestinal strictures by Photoacoustic imaging (PAI) without extrapolation from superficial biopsies. Ex vivo normal rat colon tissue, inflammatory and fibrotic intestinal strictures in rat trinitrobenzene sulfonic acid (TNBS) model were first differentiated by a PA-US parallel imaging system. Surgically removed human intestinal stricture specimens were afterwards imaged by a multiwavelength acoustic resolution PA microscope (ARPAM). The experiment results suggest that PAI is a potential tool for the diagnosis of the diseased conditions in intestinal strictures.

A Deeper Look at the Small Bowel: Training Pathways in Video Capsule Endoscopy and Device-Assisted Enteroscopy

AbstractBackgroundAlthough there are guidelines for video capsule endoscopy (VCE) and device-assisted enteroscopy (DAE), little is known about fellowship training in these technologies.AimsThe aims were to better characterize current small bowel endoscopy training in 3-year GI fellowship programs and 4th-year advanced endoscopy programs in the U.S.MethodsWe developed an online multiple-choice survey to assess current GI fellowship program training in small bowel endoscopy. The survey was distributed via email to GI fellowship program directors in the U.S.ResultsOf the 168 program directors contacted, 59 responded (response rate = 35.1%). There was no statistically significant difference in the availability of VCE or DAE between respondents and non-respondents. VCE training was universally available in 3-year training programs, with 84.8% (50/59) requiring it for fellows. The majority of 3-year GI fellows graduated with independence in VCE: 83.1% (49/59) of programs reported “most” or “all” graduates were able to read independently. DAE techniques were available in 86.4% of training programs (51/59). Training in DAE was more limited and shared between 3-year and 4th-year programs: 12.1% (7/58) of 3-year programs required training in DAE and 22.9% (8/35) of 4th-year programs required training in DAE .ConclusionsTraining in VCE is widely available in U.S. GI fellowship programs, although programs have different ways of incorporating this training into the curriculum and of measuring competency. While DAE technology was available in the majority of programs, training was less frequently available, and training is shared between 3-year fellowship programs and 4th-year advanced endoscopy programs .

Photoacoustic imaging of intestinal strictures: microscopic and macroscopic assessment in vivo (Conference Presentation)

The pathology of Crohn’s disease (CD) is characterized by obstructing intestinal strictures because of inflammation (with high levels of hemoglobin), fibrosis (high levels of collagen), or a combination of both. Inflammatory strictures are medically treated. Fibrotic strictures have to be removed surgically. The accurate characterization of the strictures is therefore critical for the management of CD. Currently the comprehensive assessment of a stricture is difficult, as the standard diagnostic procedure, endoscopic biopsy, is superficial and with limited locations as well as depth. In our previous studies, photoacoustic imaging (PAI) has recovered the layered architectures and the relative content of the molecular components in human and animal tissues ex vivo. This study will investigate the capability of multispectral PAI in resolving the architecture and the molecular components of intestinal strictures in rats in vivo. PA images at 532, 1210 and 1310 nm targeting the strong optical absorption of hemoglobin, lipid and collagen were acquired using two approaches. A compact linear array, CL15-7, was used to transcutaneously acquire PA signals generated by the a fiber optics diffuser positioned within the inner lumen of the strictures. Another approach was to use an endoscopic capsule probe for acoustic resolution PA microscopy. The capsule probe is designed for human and therefore cannot fit into rat colon. The inner surface of the intestinal stricture was exposed and the probe was attached to the diseased location for imaging. The findings in PA images were confirmed by histology results.

Characterizing intestinal strictures with acoustic resolution photoacoustic microscopy

Crohn’s disease (CD) is an autoimmune disease, which may cause obstructing intestinal strictures due to inflammation, fibrosis (deposition of collagen), or a combination of both. Identifying the different stages of the disease progression is still challenging. In this work, we indicated the feasibility of non-invasively characterizing intestinal strictures using photoacoustic imaging (PAI), utilizing the uniquely optical absorption of hemoglobin and collagen. Surgically removed human intestinal stricture specimens were investigated with a prototype PAI system. 2D PA images with acoustic resolution at wavelength 532, 1210 and 1310 nm were formulated, and furthermore, the PA histochemical components images which show the microscopic distributions of histochemical components were solved. Imaging experiments on surgically removed human intestinal specimens has demonstrated the solved PA images were significantly different associated with the presence of fibrosis, which could be applied to characterize the intestinal strictures for given specimens.