Radionuclide imaging of experimental myocarditis

The ability of ⁶⁷Ga citrate and ^99mTc pyrophosphate cardiac imaging to detect myocarditis was assessed in an experimental rabbit model. Twenty-three rabbits were imaged approximately 72 hours after infusion of i.v. norepinephrine. Diffuse cardiac uptake was found in 13 of 15 rabbits scanned with ⁶⁷Ga. Tissue distribution studies documented significant myocardial uptake of ⁶⁷Ga in those with positive scans. Precordial imaging and tissue distribution studies revealed no cardiac uptake in the eight rabbits scanned with ^99mTc. Histologic examination of all 23 hearts revealed qualitatively similar, typical lesions of myocarditis. This study suggests that cardiac imaging with ⁶⁷Ga may be useful in the detection of myocarditis.