Rectilinear scanning in the detection of acute myocardial infarction

Myocardial scintigraphy with phosphate bone scanning agents is a new and very useful development in the detection of acute myocardial infarction. Initial experience using a rectilinear scanner is described in 50 consecutive patients admitted to hospital because of suspected myocardial infarction. The routine dose was 15 mCi/5 mg, 99Tcm stannous pyrophosphate intravenously with anterior, left anterior oblique, and lateral scans obtained 45-90 minutes after injection. There was only one false negative scan in 17 patients with proven acute myocardial infarction and that was 16 days after onset. There was no proven false positive investigation in seven patients in which fresh myocardial infarction could be definitely excluded, or in a further 11 cases in which it could be excluded with reasonable confidence. Myocardial scintigraphy was considered helpful in resolving the diagnostic problem in 27 out of 29 equivocal cases. It is concluded that myocardial scintigraphy with a rectilinear scanner is a highly accurate and safe procedure in the detection of acute myocardial infarction. The optimum scanning time is two to six days after onset of suspected infarction, when a diagnostic accuracy approaching 100 per cent can be expected.