111In-labelled granulocytes in inflammatory heart diseases

Thirty-three studies in 29 patients with suspected inflammatory heart diseases (natural endocarditis, N = 10; prosthetic valve endocarditis, N = 6; perimyocarditis, N = 17) were performed prospectively using 111In-oxin-labelled granulocytes with low red cell and platelet contamination after a Percoll/plasma or Metrizamide/plasma gradient centrifugation. In four out of 10 patients with suspected natural endocarditis, circumscribed activity could be seen over the heart. Once, an additional splenic infarction could be diagnosed. Three patients with surgically proven sterile valves had a true negative scan. In three out of six patients with prosthetic valve endocarditis a pathologic 111In activity could be seen in relation to the prosthesis. Three patients showed a negative scan after 3 weeks' antibiotic pretreatment. Six out of 17 patients with suspected perimyocarditis showed a significant positive leukocyte scan. In two of the six this was proven by biopsy; in four cases, only clinical diagnosis was made. 111In leukocyte imaging is able to diagnose highly acute inflammatory heart diseases non invasively. Because of the inadequacy of other diagnostic procedures, the scan may be of great clinical importance in prosthetic valve endocarditis. Natural endocarditis can be successfully diagnosed by other procedures, but in fever of unknown origin the scan also allows the diagnosis of acute inflammatory endocarditis.