When performing 201Tl myocardial SPECT using a dual-head gamma camera on patients after exercise stress, we have observed in some a sudden increase in the counting rate between the 16th and 17th images. This increase provoked motionlike artifacts, which increased the number of false-positive findings. The aim of our study was to determine possible causes for this leap in activity. Methods: We p...

To examine the effects of coronary collateral development on thallium-201 (201Tl) distribution the left circumflex coronary artery was ligated in eight dogs. Three days later these animals ran on a treadmill, and 201-thallous chloride was injected into the right atrium at peak exercise. Scintigraphic scanning was begun within 10 min and continued for 3 hr. Scanning was repeated weekly for 6 wee...

BACKGROUND Thallous chloride (201Tl) and hexakis(2-methoxyisobutyl isonitrile) technetium (I) (99mTc-SESTAMIBI) are myocardial perfusion imaging agents with biological properties that also reflect tissue viability. Initial myocellular uptake rates of 201Tl reflect activity of Na,K-ATPase, whereas those of 99mTc-SESTAMIBI reflect mean plasma membrane potential. METHODS AND RESULTS To better un...

BACKGROUND Myocardial perfusion imaging during adenosine-induced hyperemia with dipyridamole or adenosine is an accepted method to diagnose coronary artery disease (CAD) and risk assessment. The mechanism of perfusion abnormality may be caused by disparate flow responses or coronary steal. This study examined the relation between 201Tl perfusion pattern and hemodynamic/angiographic changes duri...

To evaluate the potential cost-effectiveness of exercise 201Tl myocardial SPECT in outpatients with angina-like chest pain, we developed a decision-tree model which comprises three 1000-patient groups, i.e., a coronary arteriography (CAG) group, a follow-up group, and a SPECT group, and total cost and cardiac events, including cardiac deaths, were calculated. Variables used for the decision-tre...

Iodine-123-iodophenyl-9-methyl-pentadecanoic acid [( 123I]MPDA) and thallium-201 (201Tl) were sequentially injected in 11 patients during exercise-induced myocardial ischemia. Simultaneous dual-energy planar images were obtained at 5 min, 3 and 5 hr. All studies were concordantly either positive (8/11) or negative (3/11) by both radionuclides. Exact agreement for segmental uptake was 93%, 94% a...

OBJECTIVE To investigate patients with cystic enhancing lesions on CT and to determine whether thallium-201 (201Tl) SPECT adds to further preoperative information in differential diagnosis between gliomas and abscesses. METHODS Twenty one patients with cystic ring enhancing CT findings were studied and uptake indices were compared with CT enhancement volumes, histopathology, and survival time...

The effects of exercise training on metabolic and functional recovery after myocardial transient ischemia were investigated in a rat model. Male Wistar Kyoto rats were subjected either to a 30-min left coronary artery occlusion followed by reperfusion or to a sham operation. At 4 weeks after operation, the rats were randomly assigned either to sedentary conditions or to exercise training for 6 ...

BACKGROUND Rest thallium-201 (201Tl) myocardial perfusion imaging has been widely used for evaluation of myocardial ischemia/viability after myocardial infarction, but the ideal timing for imaging after injection to maximally estimate viability is not well established. METHODS Thirty-six patients with myocardial infarction underwent the initial, 3 h, and 24 h redistribution imaging after intr...