Gallium-67 imaging in human heart transplantation: correlation with endomyocardial biopsy

Endomyocardial biopsy seems to be the most accurate method to use for diagnosis and follow-up of acute rejection of the transplanted heart. This investigation compared a noninvasive procedure, gallium-67 imaging, with endomyocardial biopsy in the detection of acute rejection in heart transplantation. Seven male patients (aged 41 to 54 years) sequentially had 46 gallium-67 scintigrams and 46 endomyocardial biopsies between 1 week and 8 months after transplantation. Both studies were obtained in the same day, 48 hours after the administration of an intravenous injection of gallium-67 citrate. Cardiac uptake was graded as negative, mild, moderate, and marked according to an increasing count ratio with rib and sternal uptakes. Histologic findings were graded as negative, mild acute rejection, moderate acute rejection, severe acute rejection, resolving rejection, and nonspecific reaction. Negative biopsies were not found with moderate uptake, and neither moderate nor severe acute rejection were found with negative scintigrams. Imaging sensitivity was 83% with 17% false negatives and 9% false positives. Of seven studies with moderate uptake, five showed moderate acute rejection, and the patients had specific therapy with a decline in uptake, which correlated with resolving rejection. It is conceivable that in the future this technique may be used as a screening procedure for sequential endomyocardial biopsies in the follow-up of heart transplant patients.