Experimental Early Detection of Acute Mesenteric Ischemia with Functional MRI (DWI) and Parallel Imaging

Purpose: To evaluate the feasibility of diagnosing in statu nascendi mesenteric ischemia using diffusion-weighted imaging (DWI) in a porcine model. All experiments were approved by the animal care committee at the district administration. Materials and Methods: Mesenteric blood supply was studied in ten healthy female pigs (weight similar to 50 kg) with artificially induced mesenteric ischemia. In the DSA technique a branch of the superior mesenteric artery was embolized with tissue glue or small particles. DWI was performed using a 1.5 T MR scanner before embolization and 30 and 60 minutes after embolization using a 32-channel receiver coil. ADC maps were calculated for all animals. The findings were correlated to angio-graphic and autoptic findings. The image quality of DWI was assessed by means of SNR measurements and diagnostic impact by CNR measurements. Results: Embolization of the mesenteric branches was technically successful in all cases. DWI of the bowel was feasible with the applied sequences. In all animals, DWI displayed distinct cytotoxic edema as the earliest sign of ischemia thirty minutes after induction of ischemia. Furthermore, DWI yielded a distinct reduction in the water diffusion coefficient in all animals. Variance analysis showed good correlation between CNR measurements and infarction areas. Autoptic findings could confirm the detected infarction areas by DWI. Conclusion: DWI using parallel imaging techniques is feasible for the early detection of acute mesenteric ischemia. The presented DWI results offer encouraging prospects regarding more rapid disease diagnosis.