Superconducting quantum interference device magnetometer for diagnosis of ischemia caused by mesenteric venous thrombosis

Although mesenteric venous thrombosis carries a better prognosis than arterial thrombosis, mortality and morbidity are still high, Previous studies have shown that the basic electrical rhythm (BER) of the bowel decreases early after induction of arterial ischemia. Furthermore, our studies have shown that these changes occur prior to pathologic changes and that they can be recorded noninvasively using a superconducting quantum interference device (SQUID). SQUIDs measure magnetic fields that are created by the electrical activity of the gastrointestinal smooth muscle and have been used to measure the BER of the small intestine in human volunteers. This study was conducted to determine if a SQUID could be used for early noninvasive detection of mesenteric venous ischemia in an animal model. Simultaneous recordings from serosal electrodes and a SQUID outside the abdomen were taken from anesthetized New Zealand rabbits. Recordings were made for 15 minutes before and 90 minutes after injection of thrombin into the superior mesenteric vein, The basic electrical rhythm of the small bowel dropped from 16.42 +/- 0.69 to 8.80 +/- 0.74 cycles per minute at 30 minutes and to 6.82 +/- 0.722 after 90 minutes (p < 0.0001, paired t-test). The correlation coefficient between the SQUID and electrical recordings was 0.954 (p < 0.0001). These data suggest that the ischemia caused by mesenteric venous thrombosis results in changes in the bioelectrical activity, which can be noninvasively detected using a SQUID.