Mesenteric ischemia due to hemorrhagic shock: MR imaging diagnosis and monitoring in a canine model

PURPOSE: To test whether changes in the percentage of oxygenated hemoglobin (%HbO₂) and blood flow in the superior mesenteric vein (SMV) as measured with magnetic resonance (MR) imaging in vivo, can be used to diagnose and monitor mesenteric ischemia due to hemorrhagic shock in a canine model. MATERIALS AND METHODS: Eight mongrel dogs (weight range, 20-30 kg) underwent fasting for 24 hours before the experiments MR imaging measures of SMV %Hbo₂ and volume flow rate were obtained at the resting state and after 5%, 10%, and 15% of the blood volume of the dogs had been removed sequentially, which led to a total blood volume depletion of 30% in four dogs, resuscitation was performed with normal saline solution in a volume equal to the total volume of blood removed. RESULTS: SMV %Hbo₂ and SMV flow measurements at the different stages of blood removal were all significantly different (P < .05) from baseline measurements and from each other. After volume replacement with normal saline solution, SMV %Hbo₂ and flow were not significantly different (P > .05) from the baseline values. CONCLUSION: SMV %Hbo₂ and volume flow rate as measured with MR imaging in vivo, can be used to diagnose and monitor mesenteric ischemia due to hemorrhagic shock in a canine model.