Myocardial imaging: The promise and challenge of digital image processing

Abstract

Digital image processing has led to the rapid development and application of myocardial imaging techniques for the diagnosis and evaluation of patients with cardiovascular disease. One of the first major applications of digital imaging processing techniques to myocardial imaging was the development of multiple gated acquisition radionuclide ventriculography. Radionuclide ventriculography had been shown to be of value in determining ventricular ejection fraction and regional myocardial wall motion [1,2]. Although clinically useful the widespread application of this technique did not occur until computer processing allowed the acquisition and analysis of multiple images for determination of the ventricular time activity curve [3,4]. Subsequent studies have shown that digital processing of radionuclide ventriculographic images is useful in determining: ejection fraction; ventricular volumes; rates of ventricular emptying and filling, both at rest and during exercise; as well as in determining the extent of valvular regurgitation and cardiac shunting [5]. Radionuclide ventriculography with computer acquisition and processing has found wide application for the diagnosis of myocardial disease and in the evaluation of therapeutic interventions to improve cardiac function. The resting left ventricular ejection fraction as determined by radionuclide ventriculography in the post-infarction period has been found to be an important prognostic indicator. These studies and those showing that the change in ejection fraction from rest to exercise in patients with significant anatomic coronary artery disease is a better predictor of subsequent cardiovascular events and success of coronary artery bypass graft surgery than the extent of anatomic coronary artery narrowing as determined at angiography [6] promises to further increase the utility and application of this technique over the comming years.