Correlation of false negative myocardial infarct scintigraphy with postmortem studies

Abstract

Summary:Negative myocardial infarct scintigrams with """'technetium stannous pyrophosphate (99mTc-PY P) were obtained in two patients with acute massive transmural infarct. Both patients died soon after scintigraphy. Because necropsy was performed within hours after death, we were able to correlate the distribution of the tracer within the acutely infarcted tissue with the myocardial scintigram. The clinical implication is that a single myocardial scintigram may be grossly inaccurate in detecting and quantifying infarct size. The scintigraphic findings should always be correlated with the electrocardiographic and enzymatic findings in evaluating patients with possible myocardial infarct. The sensitivity of 9')"'technetium stannous pyrophosphate (O')tllTc-PY P) cardiac imaging in the detection of acute myocardial infarct (AMI) varies from 86 to 100% in patients An 83-year-old male was admitted with the classical clinical findings of an A M I . The patient had a history of myocardial infarct 19 years prior to admission and exertional angina. An admission ECG and subsequent tracings revealed the characteristic evolution of an acute anterior infarct. The admission blood pressure was 130/70 mmHg; heart rate was 72 beats/min. Creatinine kinase was 180 IU/I and rose to 670 IU/I by 12 h (normal range, 25-145).On the second hospital day, 15 mCi of 99mTc-PYP were injected intravenously. A Searle Radiographics mobile scintillation camera equipped with a medium resolution collimator (LEAP-parallel hole) was used. The pulse height analyzer was centered on an energy corresponding to a 140-keV photopeak of 99mtechnetium with a 20% window.