[Evaluation of myocarditis using T1-201 myocardial scintigraphy with bull's eye functional map]

In order to evaluate myocardial damage in a patient with myocarditis, rest thallium-201 myocardial single photon emission computed tomography (SPECT) was performed in 15 patients with myocarditis. For qualitative and semiquantitative analysis, Bull's eye functional maps were made up with SPECT images. In the functional map, the abnormal area, where T1 uptake is less than mean-2SD of the T1 uptake of normal subjects, is generally distributed in the myocarditis group. But focal and sequential abnormal areas were recognized more often in the clinically severe cases. Abnormal area tended to be observed commonly at the antero-septal wall, but it was uncommon at the lateral wall. Extent score, i.e. degree of extension of abnormal area, and severity score, i.e. degree of abnormality, were in good negative correlation with left ventricular ejection fraction (r = 0.6, r = 0.7). Furthermore, existence of abnormal area was in good correlation with the left ventricular regional wall motion. Abnormal area existed 100% in the akinetic region, 71% in the region of severe hypokinesis, and 27% in the region of hypokinesis. Abnormal area occupied 30% of the normokinetic region in the myocarditis group, which was a higher rate than in the normal control group (p less than 0.05). It was suggested that latent myocardial damage existed in the normokinetic myocardium with myocarditis. Thus, rest T1-201 SPECT with Bull's eye map is useful for clinical diagnosis in patients with myocarditis.