American journal of cardiac imaging最新文献

To determine the influence of tobacco abuse on thallium 201 lung uptake during exercise, we examined 185 consecutive subjects with normal myocardial perfusion scans and without electrocardiographic evidence of left ventricular hypertrophy. The subjects were divided into two groups: group 1 subjects (n = 60) had histories of smoking and group 2 subjects (n = 125) were nonsmokers. Eighty-eight percent of group 1 subjects and 92% of group 2 subjects were examined using single-photon emission computed tomography and the remaining patients underwent planar imaging. 201Tl lung and heart activities were quantified from the immediate anterior planar images that were obtained in all subjects and reported as lung to heart ratio (L/H). 201Tl L/H in smokers (0.39 +/- 0.11) was significantly higher (P < 0.05) than in nonsmokers (0.34 +/- 0.06) when subjects who achieved 85% of the target heart rate were compared. In conclusion, 201Tl L/H was higher in smokers than in nonsmokers when subjects who achieved 85% of the target heart rate and had no myocardial perfusion defects were compared.

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.

The last 16 years have seen the development of a variety of coronary interventional procedures based on pathoanatomy. New terms have been introduced, such as atherectomy for excision of atheroma. Coronary calcification occurs in the intima and is an important marker of significant coronary artery disease. Echocardiography of the coronary arteries can detect atheroma and calcification. Ultrafast computed tomography can quantify extent of coronary calcium. New devices, such as the rotablator, can specifically treat calcified lesions, and a lesion-specific approach is now possible. The removal of atheroma is called atherectomy. The removal of calcium is called calcifectomy. New procedures spawn new terms. Atherectomy and calcifectomy complement each other, and enable us to be specific about the pathoanatomy and the matched interventional device used. This article is an overview of the evolution of lesion-specific devices and the terminologies pertaining to their use.

Quantitative myocardial tissue characterization is being developed as an adjunct to conventional echocardiography to delineate the physical state of myocardium under diverse pathophysiological states. Real-time quantitative integrated backscatter imaging has made possible clinical investigations carried out in the United States, Europe, and Japan in patients with ischemic heart disease, hypertrophic cardiomyopathy, and cardiac allograft rejection, among others. A modification of the imaging processing used for characterization of tissue facilitates automatic detection of endocardial blood interfaces and on-line quantification of ventricular size and function, which has been recently introduced in clinical practice. Further progress and developments in quantitative ultrasonic imaging will place in perspective the clinical use of tissue characterization based on myocardial backscatter.