technetium-tc-99m-tetrofosmin and Dilatation--Pathologic

In myocardial perfusion imaging, multiple-vessel involvement of coronary artery disease (CAD) sometimes makes diagnosis difficult. Transient left ventricular (LV) dilatation on Tl-201 myocardial SPECT is a useful finding that enables the clinician to identify patients with multiple-vessel disease. The aim of this study was to confirm the utility of measuring transient LV dilatation for the detection of multiple-vessel CAD in exercise Tc-99m tetrofosmin myocardial SPECT. The participants were 55 CAD patients and 20 controls who underwent Tc-99m tetrofosmin myocardial SPECT exercise and resting imaging. During exercise, 370 MBq (10 mCi) Tc-99m tetrofosmin was injected. Exercise images were obtained 30 minutes after injection. At 210 minutes after injection, 740 MBq (20 mCi) Tc-99m tetrofosmin was administered intravenously. The rest SPECT images were acquired 30 minutes later. Thirty-six radii at every 10 degrees were generated from the center of short-axis images. An area surrounded by 36 maximal points of the myocardial Tc-99m tetrofosmin counts on each radius was calculated for exercise and rest images. The area surrounded by the 36 maximal points in the same slice of the exercise and rest images was assigned the variables A (Ex) and A(R), respectively. The transient dilatation index (TDI) of the left ventricle was calculated using the formula mean A (Ex)/A(R) in the apical, middle, and basal myocardial short-axis images. In the controls, the TDI was 0.970 +/- 0.021. In patients with CAD, the TDIs of one-vessel disease, two-vessel disease, and three-vessel disease were 1.034 +/- 0.032, 1.093 +/- 0.046, and 1.131 +/- 0.076, respectively. The TDIs were significantly greater in patients who had more occluded coronary arteries (P < 0.01). If the mean + 2SD of the TDI (1.012) in controls were assumed to be the normal upper limit, the sensitivity, specificity, and accuracy of this method in detecting two-vessel or three-vessel disease would be 91.4%, 76.9%, and 84%, respectively. The TDI is a useful index for evaluating subendocardial ischemia non-invasively and detecting multiple-vessel disease clinically.

Topics: Coronary Angiography; Coronary Artery Disease; Dilatation, Pathologic; Exercise; Female; Hemodynamics; Humans; Hypertrophy, Left Ventricular; Image Interpretation, Computer-Assisted; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Rest; Sensitivity and Specificity; Signal Processing, Computer-Assisted; Tomography, Emission-Computed, Single-Photon; Ventricular Dysfunction, Left; Ventricular Remodeling

Patients with coronary ectasia often develop chest pain and reveal ischemic changes on electrocardiograms and reduced left ventricular wall motion on left ventriculography, in the absence of epicardial coronary artery stenotic regions. We examined the disturbances in the coronary microcirculation in patients with coronary ectasia using left ventriculography and ATP loading 99mTc-tetrofosmin myocardial single photon emission computed tomography (SPECT) before and after administration of a coronary vasodilator and antiplatelet agents.. Twenty patients in whom coronary angiography revealed diffuse coronary artery ectasia but no stenotic regions were enrolled in this study. Left ventriculography and ATP loading 99mTc-tetrofosmin myocardial SPECT were performed before and after administration of the coronary vasodilator, nicorandil, as well as that of the antiplatelet agents, aspirin and ticlopidine.. (1) The ejection fraction in left ventriculography was 48.3 +/- 17.4% before, and 56.6 +/- 18.3% after the drug administration, the ejection fraction was improved after the drug administration (p < 0.05). (2) Before the drug administration, the total defect scores on 99mTc-tetrofosmin myocardial SPECT were 5.9 +/- 3.1 and 8.8 +/- 2.7 in the ATP-loading and rest images, respectively (p < 0.05), and the corresponding scores after the drug administration were 4.1 +/- 3.0 and 5.4 +/- 3.1, respectively (N.S.). Thus, the total defect scores in the ATP-loading and rest images improved after the drug administration (p < 0.05).. Myocardial damage in patients with coronary ectasia might be induced by microthrombotic embolism and microcirculation disturbance.

Topics: Adenosine Triphosphate; Aged; Coronary Vessels; Dilatation, Pathologic; Female; Humans; Male; Microcirculation; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

A 69-year-old woman presented with dyspnea on exertion. Echocardiography showed dilatation and diffuse hypokinesis of the left ventricle. 99mTc-tetrofosmin myocardial SPECT showed moderately reduced uptake in the anteroseptal wall and the inferior wall on the rest images, but was improved on the ATP loading images. 123I-BMIPP myocardial SPECT showed severely reduced uptake in the anterior wall and the inferior wall. These SPECT findings suggested ischemic heart disease rather than dilated cardiomyopathy. Coronary angiography showed no organic stenosis, but diffuse coronary ectasia was noted in three vessels. Intravascular ultrasound revealed remarkable coronary ectasia, with a maximal diameter of 8.2 mm. Coronary flow velocity as measured by Doppler blood flow guide wire was remarkably reduced. Coronary spasms were not provocated by ergonovine loading test. These findings suggested that microvascular thrombi and disturbance of dilatation caused myocardial ischemia in this patient. We treated the patient with ticlopidine and nicorandil. Following treatment left ventricle wall motion, 99mTc-tetrofosmin and 123I-BMIPP myocardial SPECT findings were improved.

Topics: Aged; Coronary Disease; Coronary Vessels; Dilatation, Pathologic; Fatty Acids; Female; Heart; Humans; Iodine Radioisotopes; Iodobenzenes; Microcirculation; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon