No abstract

Maximal elastance (E max : maximal ratio of pressure over volume) of left ventricular myocardium obtained from time-varing elastance curves represents myocardial contractility, which is independent of preload and afterload. A non-invasive method of quantifying myocardial global contractility using a single systolic PV loop was developed by Senzaki et al., and extended by Lee et al. by measuring time-volume curve using gated myocardial SPECT. Since these previous methods provide only the overall contractile function of left ventricle, we developed a method to quantify the regional contractility of myocardium. For total 55-72 regions, regional volume curve was estimated. Regional volume curves were obtained by extracting endocardial surface of left ventricle from each gated frame. Assuming the isopressure in left ventricular cavity, time-pressure curve obtained using tonometry was used for every region. We implemented software to estimate regional contractility with graphic user interface in Windows environment using VC++, in which gated myocardial SPECT is processed to acquire regional volume curve. The regional contractility developed in this study will be useful for the quantitative assessment of abnormality in regional mechanical function of myocardium in heart disease.

No abstract

Cardiologists assume that analysis of the motion of the heart (especially the left ventricle) can give some information about the health of the myocardium. We applied the myocardium model in a gated myocardium SPECT image that showed a cardiac biochemical reaction, and analyzed the motility between the gated myocardium SPECT image and the myocardium model. We constructed a left ventricle myocardium model and mathematically evaluated the motion of the myocardium. The myocardium model was created based on four-dimensional transformation.A four-dimensional transformation is defined to describe the left ventricle (LV) motion and a method is presented to estimate it from sequences of three dimensional super-ellipsoidal models that were using the sinusoidal function. To express a similar form and motion of the left ventricle myocardium, we calculated parameter functions that gave the changing of motion and form. It is continuous and regular in time and space, and periodicity in time can be imposed. The LSF (Least Square Fitting) algorithm was applied to the myocardium gated SPECT image data and the myocardium model, which finally created a fitting model.We then analyzed a regional motility direction and size of the gated myocardium SPECT constructed on a fitting model. Furthermore, we implemented the Bull`s Eye map that had evaluated the heart function for the presentation of regional motility. Using myocardium's motion, the evaluation of cardiac function of SPECT was estimated by a contraction ability, perfusion etc.