Cardiac allograft rejection monitored with ultrasound integrated backscatter

Cardiac transplant rejection was evaluated using ultrasound integrated backscatter (IB). Six adult goats received modified Mann cervical heterotopic cardiac transplants with no administration of immunosuppressive pharmacology. A-line ultrasonic backscatter from the left ventricle was collected daily for each animal until the graft ceased to yield electrical activity. Integrated backscatter with a 4-8-MHz bandwidth was calculated for each day. No biopsies were taken. Although no consistent day-to-day trend is noted, four of six goats show a decrease in backscatter over the rejection episode. In all cases, the IB increased the first two to three days after the transplant and subsequently decreased in varying magnitudes and at varying durations.