The assessment of the function and status of the left ventricle using radionuclides

The non-invasive nature or nuclear medicine techniques makes them particularly attractive for the investigation of cardiac patients. Since the early 1970's there has been a large research effort directed towards implementing nuclear cardiological techniques. Two broad types of LY functional tests have been proposed:- first pass of a bolus of radionuclide through the heart; and gated blood pool imaging of a radionuclide tracer that has equilibrated in the vasculature. The use of thallium to image the normal myocardium has also been proposed. This thesis is concerned with identifying sources of error in these radionuclide techniques. This is important both for the routine application, of the tests and for acing the tests as a research tool in cardiology. In particular, the use of rapid (about 2 minutes) LV functional testing would enable the tests to be used for serial measurement of LV function during stressing of the heart. The errors involved in measuring left ventricular ejection fraction (LVEF) and in assessing regional wall motion (RWM) are identified, and ways of correcting these errors are proposed. In order to evaluate RWM the concept of minimal detectable distance (mdd) is proposed. Following error analysis of LVEF and RWM measurement, it is proposed that rapid (about 2 minutes) acquisition is feasible for these techniques. The potential for using TAllium imaging for the detection of perfusion defects is considered, and the problems involved are identified. The use of seven pinhole tomographic imaging is proposed as a possible solution to some of the problems identified in nuclear cardiological techniques.