Significance of ultrafast computed tomography in cardiac imaging: usefulness in assessment of myocardial characteristics and cardiac function.

The usefulness of cardiac ultrafast computed tomography (CT) is discussed in this article. Thirty-three patients with ischemic heart disease and 15 patients with hypertrophic cardiomyopathy were assessed for myocardial characteristics, while 30 patients with various heart diseases were assessed for cardiac function. Volume mode (100 msec scan) and cine mode (50 msec scan) studies were applied. As the findings of abnormal myocardial characteristics, early defect (ED) and late enhancement (LE) of the left ventricular (LV) wall were observed after injection of contrast medium. In ischemic heart disease, all 27 patients with myocardial infarction (MI) and all 16 MI sites showed LE, while 25 ED sites were well correlated with MI or significant coronary stenosis. LE was quite sensitive for MI and ED was highly predictive for ischemia. Seven of 15 HCM patients (47%) also showed LE, indicating that LE occurs in tissues with a different capillary architecture from that observed in normal myocardium. For evaluation of cardiac function, ventricular volumetry was performed by summation of a sliced area of the ventricles. End-diastolic volume and LV ejection fraction calculated by this means correlated excellently with the values obtained using left ventriculography (R = 0.97 and 0.96). The stroke volumes for both ventricles were nearly equal when calculated using ultrafast CT. Consequently, the study of cardiac volumetry using ultrafast CT was thought to be reliable and utilizable in clinical practice.