The Utility of Hand-held Ultrasound Devices to Detect Bowel Wall Inflammatory Activity in Crohn's Disease

• Aim 1. Comparison of the accuracy of hand-held US machines for the detection and measurement of bowel wall inflammatory activity to that of advanced high-end and premium US machines by experienced IUS performers

• Rationale: IUS use has been incorporated into the processes of diagnosis, follow-up, monitoring, and treatment approaches in CD. One of the limiting factors of IUS dissemination relates to the high costs of the modern high-end and premium US machines used for intestinal ultrasound. Confirming the acceptable accuracy of affordable modern hand-held US machines for detection and measurement of inflammatory activity will enable dissemination of IUS use, as obtaining affordable and precise US machines will be possible.
• Overall Experimental Strategy and/or Methodology: 150 CD patients will undergo an IUS exam using a hand-held US machine (GE VSCAN air or Philips Lumify) followed by an exam using a high-end or premium US machine (GE S-8, BK 3000 and GE E-9). All exams will be performed by one of 3 experienced IUS performers (DC, AA, HB). The exams will be performed using the same consecutive method with a low-frequency curved array transducer enabling all abdominal quadrants to be examined for fill levels, potential pathological distension, motility, and para-intestinal structures such as abscesses, followed by examination using a high-resolution linear array for detailed examination of the bowel wall structure. All examinations will be performed without any preceding preparation, using a consistent technique and protocol, beginning the examination with the terminal ileum (TI), proximal to the distal colon, followed by an examination of the small bowel. The assessment will be performed for features of inflammation, especially bowel wall thickness of the TI and the colon. Bowel wall thickness will be measured at least in two different areas at a minimal distance of 1 cm from each other. Colonic bowel thickness will be measured at the right, transverse, left, and sigmoid colon. Small bowel wall thickness will be measured at the TI. The thickest measurement of each bowel segment will be chosen as a representative for measurement. Images and cine-loops of each segment of the colon and the TI will be saved on the tablet connected to the hand-held US machine.

Other signs of inflammation will also be examined: Doppler signs within the bowel wall using the modified Limberg scoring system, mesenteric fat hypertrophy, stratification of bowel wall layers and enlargement of lymph nodes.

Intramural and extramural complications including strictures with\without pre-stenotic dilatations, fistulas, and abscesses will be noted and the relative images will be saved.

The findings of different signs of inflammation described will be compared between the hand-held ultrasound and the high-end \ premium US machines. A dichotomic comparison for the presence of each sign (yes/no) will be followed by a comparison of numerical parameters (exact bowel thickness measurement for each segment and Limberg score).