[Clinical applicability of myocardial scintigraphy with gallium-67 in the study of dilated cardiomyopathy].

Gallium-67-citrate imaging has been recently proposed, in addition to endocardial biopsy, to detect myocardial inflammation in idiopathic dilated cardiomyopathy (IDCM). In order to evaluate the clinical usefulness of this method, 33 patients (pts) suffering from IDCM, 24 pts with various other cardiac diseases (inflammatory etiology in 7), and 11 controls underwent Gallium-67 scintigraphy (anterior and 30 degrees left anterior oblique projections; acquisition at 48 and 72 hrs). In 31 pts repeated scintigraphic examinations (at least two) were obtained. Scans were interpreted by two independent observers. Positivity of scintigrams was based on three different criteria: 1) myocardial activity greater than that of the sternum; 2) presence of focal myocardial activity; 3) semiquantitative index (index = activity of sternum/myocardial activity). Significant differences, either in the percentage of positive scans or in the values of the semiquantitative index, were found between controls and all pts with cardiac diseases. However, no difference was observed when comparing pts with IDCM to pts with other cardiac diseases. Finally, among the pts with cardiac disorders other than IDCM, the qualitative and semiquantitative results of the 7 pts with inflammatory etiology of the disease were similar to those obtained in the remaining 17. Of those pts who underwent longitudinal study, about a third showed modified scintigraphic results later on. No significant difference in behaviour was observed between IDCM and other cardiac disorders. Therefore, we conclude that Gallium 67-citrate imaging does not appear to be a suitable method for the identification of pts. with IDCM. The usefulness of this technique should be tested in samples of pts should previously selected with other more specific methods.