Potential application of new imaging modalities in the measurement of cardiac volumes and characteristics.

Developments of various imaging modalities in recent years have resulted in imaging systems with greater spatial resolution, faster data acquisition, and more powerful computer processing. It is the purpose of this report to examine three of these systems, positron emission tomography (PET), magnetic resonance imaging (MRI) and ultrafast computed tomography (cine-CT) with respect to their applicability for determination of cardiac volumes and other characteristics related to hypertension. While each of these modalities has widespread applications and specific advantages, this report will be primarily concerned with two objectives: functional ability to record indicator dilution curves suitable for quantification of flow and the anatomic or geometric ability to measure chamber dimensions with high accuracy. Time concentration curves have been outlined on all modalities and used for quantification of myocardial perfusion and myocardial reserve. Only one modality, cine-CT, determined cardiac output by dilution curves although in vivo arterial recording from PET has demonstrated suitable curves for this application. Both MRI and cine-CT have demonstrated accurate determination of chamber volumes by the geometric method, the latter giving somewhat higher spatial resolution. The advantages of these machines for such purposes have yet to be determined.