American journal of cardiac imaging最新文献

The electron beam computed tomography (EBCT) provides a safe, rapid, and noninvasive means to detect the presence and quantitate the deposition of calcium in the coronary arteries. To examine the inter-rater reliability of a coronary calcification screen using the EBCT, films from 50 subjects were scored by two technicians. The number, volume, and calcification scores were determined for each artery as well as a total score of coronary calcification. When scan results were interpreted qualitatively (all scores > 10 classified as positive) there was complete agreement between raters in identifying the 22 cases with a positive total scan, and only one instance of discrepancy in identifying positive results for specific arteries. When scores for the 32 cases with non-zero calcium scores were analyzed quantitatively, inter-rater correlation coefficients of 0.98 or higher were observed for the total scan scores and for scores in three of four arteries. In only four cases did the total scan scores from the two raters differ by more than 10%. Therefore, evidence suggests that EBCT films can be reliably scored, enhancing their potential usefulness in the early detection of coronary atherosclerosis.

This article evaluates the pattern and effect of varying loading conditions on pulmonary venous flow and transmitral flow obtained by transthoracic and transesophageal echocardiography. We have conducted a two-stage study. A transthoracic echocardiographic study was performed in 15 patients with coronary artery disease and preserved left ventricular function. The transesophageal approach was used before open heart surgery where hemodynamic conditions were invasively monitored. Sublingual nitroglycerin (NTG) was administered to lower systolic blood pressure (mean 18 mm Hg) and resulted in a significant decrease in the peak passive left ventricular diastolic filling velocity (E wave) from 72 +/- 23 to 49 +/- 16 cm/s without marked changes in pulmonary venous flow pattern. In the transesophageal part of the study, Doppler-derived systolic (J), diastolic (K), and retrograde (R) phases of pulmonary venous flow, and passive (E) and active (A) phases of mitral flow were measured. Hemodynamic data were obtained invasively. Loading conditions were increased by infusion of saline and phenylephrine and reduced by NTG. Increased preload resulted in an augmented mitral E wave, an increased J wave, and an increased retrograde flow wave from the pulmonary veins. These changes were reversed by reduction of preload with NTG. Monitoring mitral and pulmonary venous flow may provide a relatively noninvasive means to assess directional changes in left ventricular preload.

Fluoroscopy is a reliable, easy, and readily available technique to follow-up prosthesis functioning after heart valve surgery. The different orientation given to the prosthesis may represent a limitation of the technique accounting for unsatisfactory results in 10% to 40% of the cases. The aim of the study was to evaluate whether and to what extent different intraoperative valve orientation influence feasibility and accuracy of postoperative fluoroscopic evaluation of bileaflet prostheses. We prospectively evaluated 90 patients who had aortic, mitral, and/or tricuspid valve replacement with Sorin Bicarbon or CarboMedics bileaflet prostheses. Fifty percent of the patients in each group were randomly assigned to receive prostheses oriented in a perpendicular or a parallel position with respect to the ventricular septum. Fluoroscopic evaluation was considered appropriate when the prosthesis' "tilting disk" projection was obtained. The valve's hemodynamic performance was investigated through Doppler study. A proper fluoroscopic evaluation was rapidly (15 +/- 5 seconds) achieved in all patients with the former orientation, whereas it was impossible to obtain it in 8 of 20 (40%), 19 of 20 (95%), and 4 of 5 (80%) of patients with the latter orientation. In the remaining patients extremely angulated, uneasy projection was often required to get a correct fluoroscopic image. The Doppler study showed a similarly favorable hemodynamic performance regardless of valve orientation. Prosthesis orientation crucially affects the rate of success of the fluoroscopic evaluation. The orientation perpendicular to the ventricular septum greatly facilitates the postoperative feasibility and accuracy of fluoroscopy, and it is not detrimental to the valve's hemodynamic performance. This valve orientation may provide a better fluoroscopic window whenever a valve dysfunction is suspected.

Coronary artery scanning using electron beam computed tomography is a diagnostic tool with application to high-risk and symptomatic subjects that can assist in diagnosing or excluding coronary artery disease. Although there is ample evidence for the utility of this and related technologies for diagnosis in symptomatic subjects, this remains an unproven technology for screening healthy asymptomatic subjects. Because of its potential in this regard, further research should be encouraged to determine its place in the armamentarium of diagnostic tools. In contrast to its unproven utility for screening asymptomatic populations, electron beam computed tomographic coronary calcium has shown fairly accurate association with coronary angiographic findings in symptomatic patients referred for angiography for chest pain syndromes.

Pharmacological stress testing with Tc-99m sestamibi is being used extensively for the diagnosis of coronary disease. Although there are no randomized and prospective studies using this technique for preoperative evaluation of patients undergoing noncardiac surgery, there are several studies that indicate that it is equivalent to exercise perfusion imaging and can be used for evaluating the prognosis of patients with coronary artery disease (CAD). This review will discuss these studies.

A 72-year old man was injected with Tc 99m tetrofosmin during acute chest pain, in the presence of a nondiagnostic electrocardiogram (ECG). Myocardial perfusion imaging revealed a large anteroseptal defect. Subsequent catheterization confirmed left anterior descending artery disease. Acute imaging may be useful in the identification of critical disease in patients with chest pain and nondiagnostic ECG.

Preoperative cardiac risk stratification has been traditionally performed using clinical variables indicative of increased cardiac risk, more recently dipyridamole-thalium imaging has been used with variable success. Several well-designed clinical studies have now shown that DSE is a feasible, safe, and useful modality for cardiac risk stratification before surgical procedures; its accuracy is comparable to nuclear perfusion testing. DSE has the additional advantages of having a relatively lower cost and providing additional information regarding ventricular and valvular function.