Predicting Intestinal Viability After Acute Mesenteric Ischemia by Photoacoustic Imaging: An Experimental Study in Rats

Our purpose was to assess the ability of photoacoustic imaging (PAI) to objectively predict ischemic intestinal pathological damage during surgery for acute mesenteric ischemia (AMI). PAI uses laser light to detect relative amounts of oxygenated and deoxygenated hemoglobin in intestinal tissue. In 18 rats, AMI was induced by clamping the mesenteric and marginal vessels of the ileum for 0 minutes in the sham group (n = 6), 30 minutes in the mild group (n = 6), and 180 minutes in the severe group (n = 6). After 60 minutes of reperfusion, the damage of the intestine was evaluated pathologically. Oxygenation of the intestine was monitored throughout the procedure in real time by the PAI system and compared between the mild and severe groups. All rats showed irreversible (i.e. transmucosal or transmural infarction) damage in the severe group. After reperfusion, the oxygenation in the mild group recovered immediately and was significantly higher than in the severe group at 1, 5, 10, 30, and 60 minutes (P = .007, 014, 016, 008, and 003, respectively). Oxygenation showed a significant strong negative correlation with the pathological severity. In conclusion, PAI could objectively predict irreversible ischemic damage immediately after reperfusion, which potentially prevents inadequate surgery.