Faculty Bibliography

Quantitation of myocardial blood flow has been sought by the clinician using a variety of imaging modalities and blood indicator dilution techniques. Ultrafast computed tomography has real potential for clinically useful estimations of regional myocardial blood flow. At the present time, there are limitations with this technique and early washout of indicator (iodine) appears to be the most likely explanation for the inaccuracies observed. Several methods have been tried to correct for early washout without success. Preliminary data based on a new algorithm look promising. Currently available techniques for detecting and quantifying myocardial ischemia have significant limitations. A noninvasive method able to determine wide ranges of flow with accuracy will be essential to understand the pathophysiology of ischemia and for directing better methods of managing ischemic heart disease.

Ultrafast computed tomography (CT) is a new imaging technique that relies on electron beam technology. Its short scanning acquisition times eliminate the motion artifacts seen with conventional CT. High temporal and spatial resolution make it ideal for evaluating the heart using only modest amounts of intravenous contrast. Ultrafast CT is extremely valuable for diagnosis and assessment of intracardiac thrombus and cardiac tumors. Although echocardiography is widely used to identify intracardiac thrombus, it sometimes cannot visualize the most common sites, the atria (especially the left atrial appendage) and the cardiac apex. These areas are clearly defined by ultrafast CT. Likewise, the location, size, extent, and tissue density of primary or metastatic cardiac tumors can be characterized using ultrafast CT, which may obviate the need for angiography before operative treatment.