Reversible Thallium Defects Research Articles

Noninvasive diagnostic test choices for the evaluation of coronary artery disease in women: A multivariate comparison of cardiac fluoroscopy, exercise electrocardiography and exercise thallium myocardial perfusion scintigraphy

Several diagnostic noninvasive tests to detect coronary and multivessel coronary disease are available for women. However, all are imperfect and it is not yet clear whether one particular test provides substantially more information than others. The aim of this study was to evaluate clinical findings, exercise electrocardiography, exercise thallium myocardial scintigraphy and cardiac fluoroscopy in 92 symptomatic women without previous infarction and determine which tests were most useful in determining the presence of coronary disease and its severity. Univariate analysis revealed two clinical, eight exercise electrocardiographic, seven myocardial scintigraphic and seven fluoroscopic variables predictive of coronary or multivessel disease with 70% or greater stenosis. The multivariate discriminant function analysis selected a reversible thallium defect, coronary calcification and character of chest pain syndrome (p less than 0.05) as the variables most predictive of presence or absence of coronary disease. The ranked order of variables most predictive of multivessel disease were cardiac fluoroscopy score, thallium score and extent of ST segment depression in 14 electrocardiographic leads. Each provided statistically significant information to the model. The estimate of predictive accuracy was 89% for coronary disease and 97% for multivessel coronary disease. The results suggest that cardiac fluoroscopy or thallium scintigraphy provide significantly more diagnostic information than exercise electrocardiography in women over a wide range of clinical patient subsets.

Myocardial thallium 201 imaging in hypertrophic obstructive cardiomyopathy.

Thallium 201 Myocardial perfusion imaging was performed at rest and during exercise in 14 patients with hypertrophic obstructive cardiomyopathy without coronary artery disease. The regional myocardial Thallium201-uptake and distribution ratio of these patients were analysed by a semiquantitalive computerized method and compared with those of six normal subjects. Four of the 14 patients had no Thallium201 imaging defect. Out of a total of260 analysed regions of interest in the remaining patients, five regions with reversible and 25 with irreversible Thallium201 defects could be demonstrated. Most of these defects were localized in the interventricular septum. The Thallium201 defects were not related to the age of the patients and there was no relationship between the occurrence of reversible Thallium201 defects and a pathological myocardial lactate extraction rate during maximal atrial pacing. In patients with left ventricular outflow obstruction at rest (n= 10) the percentage of irreversible defect regions in the Thallium201-scintigram (8.5%) was more than twice as high as in those patients with a provocable pressure gradient (3.9%). These data suggest that hypertrophic obstructive cardiomyopathy is often associated with regional ischemia or fibrosis despite normal coronary arteries. Therefore, in these patients, Thallium201 scintigraphy can not be used as a non-invasive screening method to exclude or prove coronary artery disease