High Resolution Microultrasound (µUS) Investigation of the Gastrointestinal (GI) Tract.

ABSTRACT

High resolution, microultrasound (µUS) scanning of the gastrointestinal (GI) tract has potential as an important transmural imaging modality to aid in diagnosis. Operating at higher frequencies than conventional clinical ultrasound instruments, µUS is capable of providing scanned images of the GI tract with higher resolution. To investigate the use of µUS for this application, a phantom which is cost effective, within ethical guidelines and, most importantly, similar in histology to the human GI tract is necessary. Therefore, a phantom utilizing porcine small bowel tissue has been developed for custom assembled µUS scanning systems. Two such systems, a stepping scanner and a continuous sweep scanner were utilized to repeatedly scan regions of prepared samples of porcine small bowel tissue. The porcine small bowel tissue phantom was perfused with degassed phosphate buffer saline (dPBS) solution through a cannula inserted in its mesenteric vessel to simulate in vivo conditions and achieve better µUS mucosal characterization. The µUS system scans a transducer across the tissue phantom to acquire RF echo data, which is then processed using MATLAB. A B-scan reconstruction produces 2D images with relative echo strength mapped to a color map of the user's choice. The phantom developed also allows for modifications such as the insertion of fiducial markers to detect tissue change over time and simultaneous perfusion and scanning, providing a platform for more detailed research and investigation into µUS scanning of the GI tract.