Detecting coronary artery disease by electron beam CT.

Electron beam computed tomography is a sensitive method for detection and quantitation of coronary artery calcification. The absence or presence and the amount of coronary artery calcification has prognostic significance for the existence of occlusive coronary artery disease and the risk of developing angina pectoris, myocardial infarction, and sudden death.

Transesophageal echocardiographic diagnosis of pulmonary arteriovenous malformation. Role of contrast and pulsed Doppler echocardiography.

Contrast echocardiography produced by peripheral injection of agitated saline solution is widely used for detecting intracardiac and intrathoracic extracardiac shunts, like pulmonary arteriovenous malformation (PAVM). Currently, localization of PAVM requires pulmonary angiography even after detection by computed tomography of the chest. Pulsed Doppler along with contrast echocardiography of the pulmonary veins performed during transesophageal echocardiography may aid in the localization of PAVM and in its diagnosis.

Cardiac magnetic resonance imaging.

All four cardiac valves can be imaged using MRI. Gradient-echo imaging is the preferred mode of imaging. Valvular regurgitation seen as an area of signal loss in the more proximal chamber can be diagnosed with a high degree of accuracy when compared with 2-D Doppler echocardiography and catheterization angiography. Aortic and mitral stenosis can be semiquantitatively diagnosed, but no method for determining valve areas is currently available. Cardiac prosthetic valves can be imaged but appear only as localized signal loss. Prosthetic valve regurgitation can be diagnosed in the same way as native valve regurgitation. At present, MRI, though not a widely used modality, can contribute significantly to the diagnosis of cardiac valve disorders. With the addition of fast magnetic resonance scanning, which can eliminate the need for electrocardiographic gating, it will be possible for patients with cardiac rhythm irregularities to be scanned, thus broadening the base of patients with valve disease who can be diagnosed.

Clinical application of magnetic resonance imaging of the heart and great vessels.

This report reviews the clinical applications of magnetic resonance imaging, (MRI) for the heart and great vessels based on the first 120 patients studied with 1.5 Tesla scanner. Cine scans were obtained in 85% of patients studied with the remainder having T1 spin-echo imaging. MRI provides high-resolution multiplanar images for defining abnormalities in cardiac structure and is especially useful for congenital heart disease. Cine MR evaluates cardiac dynamic functions such as left ventricular volumes and ejection fraction, left ventricular segmental wall motion, and valvular function. It is also useful for detection of aortic and pulmonary arterial disease and diseases of the pericardium. It is concluded that MR has broad applications for diagnosis of cardiac and great-vessel disorders.

Applications of MRI for diagnosis of cardiovascular diseases.

Magnetic resonance imaging (MRI) acquires high spatial resolution images of the heart from any part of the cardiac cycle and in any planar configuration without use of contrast. Sequential images through the cardiac cycle can be viewed as a cine.

Magnetic resonance imaging vs. ultrafast computed tomography for cardiac diagnosis.

Ultrafast computed tomography (CT) and magnetic resonance imaging (MRI) generate high resolution tomographic cardiac images. Ultrafast CT requires intravenous injection of x-ray contrast combined with an image acquisition time of 50 msec. MRI requires no contrast injection, but has relatively long acquisition times due to gating. Both technologies can be used to evaluate cardiac chamber and great vessel dimensions, intracardiac and extracardiac masses, ventricular hypertrophy, left ventricular mass, congenital heart disease, regional and global left ventricular function, right ventricular function and pericardium. MRI is highly useful for detection and semi-quantitation of valvular regurgitation while ultrafast CT is not. Aortic and mitral valve stenosis can be detected by both, but MRI is the preferred study. Though both techniques can be used to assess coronary artery bypass graft status, ultrafast CT is the preferred method. It is concluded that ultrafast CT and MRI have broad applications for cardiac diagnosis.

Coronary artery dissection--a case report.

Coronary artery dissection, both spontaneous and catheter-induced, is associated with a significant morbidity and mortality. The authors present a case of a middle-aged woman with spontaneous right coronary artery dissection causing inferior wall myocardial infarction and left coronary artery dissection at the time of coronary arteriography. It is suggested that emergency aortocoronary bypass surgery be performed preceded by insertion of an intra-aortic balloon in acute evolving cases where coronary anatomy is favorable to limit infarction and avert loss of life.

Preliminary experience in the use of ultrafast computed tomography to diagnose aortic valve stenosis.

Eight patients, mean age 72 years, with aortic valve stenosis were studied by ultrafast CT 1 day after cardiac catheterization. After injection of radiographic contrast material through a peripheral vein, two contiguous eight-level R wave-triggered cine mode scans in the short axis were acquired, starting above the aortic valve and continuing through the apex of the left ventricle. Seven of eight patients, all with calcified aortic valves, had a detectable central orifice. Catheterization-derived aortic valve areas were within 0.25 cm2 of the CT valve areas in six of seven. LV mass was measured by ultrafast CT in the eight patients with aortic valve stenosis (121.6 +/- 18.2 gm/m2) and was found to be significantly higher (p less than 0.0001) than that in a group of eight subjects with normal LV function, no history of hypertension, and normal ECGs (73.0 +/- 13.1 gm/m2). It is concluded that in selected cases ultrafast CT can contribute to the assessment of severity of calcific aortic stenosis by measurement of LV mass and valve area.

Determinants of left ventricular ejection fraction by ultrafast computed tomography.

Twenty-seven patients had left ventricular ejection fraction (LVEF) measured by catheterization, single-plane angiography, and ultrafast computed tomography (cine CT). Twelve patients (mean age sixty-two years) had LVEF measured by use of the cine CT long-axis view LAV), and 15 patients (mean age fifty-eight years) had LVEF measured by use of the cine CT transaxial view (TAV). Cine CT LVEF was measured by means of two methods of edge detection (M1 and M2). A significant correlation was found between single-plane angiography and cine CT LAV LVEF (M1, r = .96; M2, r = .93). A lesser correlation was found for catheterization vs TAV cine CT LVEF (M1, r = .77; M2, r = .81). There was no significant difference between the two methods of edge detection for determining LVEF (M1 vs M2: LAV, r = .98; TAV, r = .94); however, there was significant variability in cavity volumes. Therefore, the LAV is superior to the TAV for measurement of LVEF by cine CT; however, different methods of edge detection, though affecting volumes, may not affect LVEF.