Diagnostic Ability of Arm Exercise Thallium-201 SPECT in Detecting Coronary Artery Disease

BACKGROUND: Exercise testing is a standard noninvasive method used in the evaluation and management of patients with suspected coronary artery disease. However, patients with lower limb impairment are unable to undergo a standard bicycle or treadmill test. Alternative methods of exercise testing are needed for patients with vascular, orthopedic or neurologic conditions who cannot perform leg exercise. This study was aimed to determine the diagnostic accuracy of arm exercise thallium-201 SPECT for evaluating chest pain in patients unable to perform leg exercise. METHOD: Twenty-five anginal patients performed arm ergometry testing in conjunction with thallium-201 SPECT. Thereafter all underwent coronary angiography. RESULT: Significant coronary artery disease (> or =50% stenosis) in at least one vessel was present in 22 (88%) of the 25 patients. The sensitivity of thallium-201 SPECT for detecting coronary artery disease was 91%, which was significantly higher than the 32% sensitivity found with the electrocardiographic response alone (p <0.001). Thallium-201 SPECT yielded a sensitivity of 88, 86 and 100% for one, two, and three vessel diseases, respectively, and an 84% sensitivity and 81% specificity for detecting individual vessel stenosis. CONCLUSION: Arm exercise thallium-201 SPECT is useful for detecting coronary artery disease in patients unable to perform leg exercise. In addition, it provides an information regarding exercise tolerance. Therefore, this test appears to be reliable and useful and should be considered in the detection of coronary artery disease in nonambulatory patients.

The Significance of Thallium-201 SPECT in the Diagnosis of Brain Tumors: Clinical Analysis

Thallium-201 SPECT has shown varing uptakes in tumors, depending on their viability, the type, and degree of malignancy. The authors analyzed Thallium-201 SPECT in brain lesions quantitatively, to predict the degree of malignancy, to differentiate between high and low grade astrocytic tumor by thallium uptake, and to differentiate radiation necrosis from tumor recurrence. The thallium indices were 1.56+/-0.75 in the benign brain tumors and 2.5+/-1.13 in the malignant brain tumors(p<0.05). There was differences in thallium index between high(2.19+/-0.61) and low(1.87+/-0.81) grade astrocytic tumor, however it was not statistically significant(p=0.55). The diagnostic accuracy of thallium index in differentiating benign from malignant was 82.5% by a threshold of 1.5. The mean thallium index of radiation necrosis was lower than that of recurrence(1.33/2.22). In conclusion, Thallium-201 SPECT may be useful for the diagnosis and evaluation of brain tumors to predict the degree of malignancy.

Thallium-201 SPECT in Differential Diagnosis of Malignancy from Benign Pathology in Patients with a Solitary Pulmonary Lesion / 대한핵의학회잡지

PURPOSE: T1-201 SPECT has been used in differentiating benign and malignant pulmonary lesions. While its sensitivity may be high, the specificity and predictive values are reported to be variable depending on the type of benign lung lesion. The purpose of this study was to prospectively assess the efficacy of T1-201 SPECT for differentiating benign and malignant single pulmonary lesions in a population with a high prevalence of begin pulmonary lesions, especially, tuberculosis. MATERIALS AND METHODS: One-hundred thirty-three patients, having 89 malignant and 44 benign lesions(23 active tuberculosis, 5 inactive tuberculosis, 3 aspergilloma, 3 focal pneumonia, 2 thymoma, and 8 others), were imaged using a dual-headed system at 15 minute(early) and 3 hour (delayed) following administration of 111MBq T1-201. The images were read visually and lesion-to-background ratios(L/B) were obtained from transverse tomographic slices. Retention index was expressed as [(delayed L/B-early L/B) / early L/B]. RESULTS: 82/89(92%) and 83/89(93%) of the malignant lesions were visually positive on the early and delayed images, and 27/44(61%) and 26/44(59%) of the benign lesions wefe also between the mean L/B's of the malignant and benign lesions, L/B was not useful for differentiating the two due to a large overlap. There was no difference in retention indices. CONCLUSION: Despite of its high sensitivity, the specificity of T1-201 SPECT was unacceptably low in patients with active benign lesions. The positive and negative predictive values for lung cancer in a population with a high prevalence of the benign single pulmonary lesion was only marginal.

Correlation of Infarct Size and Late Troponin T Peak Concentration in Acute Myocardial Infarction / 대한내과학회지

OBJECTIVES:The estimation of infarct size has been important in evaluation of prognosis of the patients who had acute myocardial infarction. The infarct size estimated by the thallium-201 SPECT has been known to correlate with the prognosis of patient. The enzymatic estimation by the total release of creatine kinase isoenzyme MB(CK-MB) has been widely used in estimating infarct size clinically, but inconvienent and not cardiospecific. Recently, serum troponin T, cardiospecific myofibrillar protein, has been used in the diagnosis of acute myocardial infarction, and used in the estimation of reperfusion following myocardial infarction. To assess the role of the late troponin T peak concentration on the estimation of infarct size, this prospective study was carried out. METHODS: The patients with acute myocardial infarction who were admitted, within 48hours after the onset of chest pain, to Ajou University Hospital between April 1995 and August 1995 were evaluated. All patients were divided into anterior and inferior infarct and checked serum troponin T and CK-MB serially, and underwent stress Thallium-201 SPECT 1 week after infarction, In each group, we assessed the correlation of the late toponin T peak concentration, the total release of CK-MB, and the infarct size estimated by thallium-201 single photon emission computed tomography(SPECT). RESULTS: 1) The eligible subjects consisted of 22 patients (17 men and 5 women), and age ranged from 29 to 77 years(mean 57.8 +/- 12.5 years). 2) The mean arrival time to the hospital after the onset of chest pain was 15.5 +/- 13.2 hours. The 19 patients had at least one risk factor for coronaryartery disease. 3) The late troponin T peak concentration and the total release of CK-MB in patients with anterior infarction were not different from those with inferior infarction. The infarct size estimated by the thallium-201 SPECT in patients with anterior infarction was larger than patients with inferior infarction The left ventricular ejection fraction in anterio infarction was lower than inferior infarction. 4) The late troponin T peak concentration ha: positive correlation with the infarct size estimated by the thallium-201 SPECT in the total patients, and both patients with anterior infarction and inferio infarction. 5) The total release of CK-MB correlated with the infarct size estimated by the thallium-20 SPECT in the total patients, and the patients of inferior infarction. CONCLUSION: The late troponin T peak concentration was more accurate than the total release o CK-MB in the estimation of infarct size. Therefore, when the patient arrived to the hospital less than 48hr after the onset of chest pain, the late troponin T peak concentration is useful in the decision and evaluation of therapeutic intervention and in the prediction of prognosis.

Thallium-201 SPECT Imaging of Brain Tumors

Thallium-201 SPECT studies were done on 32 patients with brain tumors : 20 patients with glioma, 3 patients with meningiomas, 2 patients with metarastasis, 2 patients with pineal tumors, 1 patient each with germinoma, neurinoma, neurocytoma, and 2 postradiation patients. A 201T1 index was based on the ratio of thallium uptake tumor versus the homologous contralateral brain. It was calculated and compared with tumor histology. There was a substantial uptake of 201T1 in high grade gliomas with no uptake in low grade glioma. Meningiomas and metastatic tumors show hot uptake, revealing that 201T1 uptake is not exclusive to high grade gliomas. In conclusion, 201TI SPECT could distinguish the benign and malignancy, and seems to be useful in the follow-up after treatment, to period low-or high-grade lesions.