Myocardial emission tomography with thallium-201. Value of multiple and orthogonal sections in the study of the myocardial infarction.

The usefulness of transverse, sagittal, and frontal tomographic images was assessed in the study of the myocardium labelled with thallium-201. In a series of 20 patients with myocardial infarcts in various locations documented by clinical, electrocardiographical, and biochemical data in 15 cases and uncertain diagnosis in 5 cases, the sections reconstructed from 32 views obtained with a rotating scintillation camera were compared to the conventional views. Quantitatively, the mean myocardium-to-background activity ratio improved significantly from 1.60 to 2.57 (p less than 0.001); qualitatively, the presence, site, and size of the defect were more easily determined on the sections and generally showed a sharp contrast to the normal tissue; transverse sections enabled us to explore the anterior infarcts, but sagittal or frontal views were required for inferior locations. The tomographic exploration was normal in only patient whose diagnosis was uncertain. These results suggest that three-dimensional emission tomography can improve both detection and quantification of the myocardial infarct.