Histological correlates to pig gastrointestinal wall layers imaged in vitro with the magnetic resonance endoscope

Background & Aims: The magnetic resonance endoscope consists of a nonferromagnetic endoscope with a receiver coil incorporated into its tip. The aim of this study was to define the anatomic correlates of the gastrointestinal wall layers imaged in vitro with the magnetic resonance endoscope. Methods: Twenty-two tissue specimens from various segments of the porcine gastrointestinal tract were imaged with the magnetic resonance endoscope using up to four different scanning sequences. Cyanoacrylate, serving as a marker, was randomly injected into the tissue strips before imaging. Histological sections were then compared with the magnetic resonance images. Results: T1-weighted spin echo sequences yielded the highest image quality and typically showed three wall layers that corresponded to distinct histological layers. The mucosa showed high signal intensity, the submucosa low signal intensity, and the muscularis propria an intermediate signal intensity. In the esophagus and rectum, the muscularis propria could be visualized as separate circular and longitudinal layers, Conclusions: In vitro imaging with the magnetic resonance endoscope shows three to five wall layers of the porcine gastrointestinal tract depending on the segment scanned. This degree of gut wall resolution suggests that endoscopic magnetic resonance imaging may have potential for local staging of gastrointestinal tumors.