Ga-67 myocardial scintigraphy in patients with acute myocarditis.

Four patients with acute myocarditis were examined by Ga-67 myocardial scintigraphy. Two cases showed positive scintigram. In one of these cases, the first scintigram showed positive one month after onset of acute myocarditis, and three and four months after its onset, Ga accumulation slightly decreased intermittently. However, six months after its onset, the scintigram showed strongly positive again. Endomyocardial biopsy of this case six months from its onset showed some mononuclear cell infiltration in the myocardial interstitium. From these changes of scintigram during the course of the disease and biopsy findings, this case appeared to be one of "smoldering" or "chronic recurrent" myocarditis. Another case showed weakly positive one month after onset of disease, in spite of a negative CRP. In the remaining two cases, Ga-67 scintigram showed negative, although CRP was + and 5+, respectively. The sensitivity of the Ga-67 myocardial scintigram may not be very high. But when it continues to show positive, acute myocarditis seems to be "smoldering" and transferring to DCM. Ga scintigram is a noninvasive examination for myocarditis and is a useful screening test for identifying myocarditis, and serial scans may eliminate the need for frequent biopsies in suspected myocarditis cases.