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At least 1,063 records · Page 59Linked to original sources
PubMed1994

Differentiation of malignant glioma and metastatic brain tumor by thallium-201 single photon emission computed tomography.

The use of superdelayed thallium-201 single photon emission computed tomography (201Tl SPECT) for differentiating malignant gliomas from cerebral metastases was investigated in 23 patients (7 with meningioma, 6 with glioma, 7 with cerebral metastasis, 1 with each of neurinoma, abscess, and necrosis). 4 mCi of 201Tl was injected intravenously, and gamma camera scans were performed after 10 minutes and 4, 24, 72, and 96 hours (superdelayed scan). The mean thallium index of meningiomas was significantly higher than those of gliomas and cerebral metastases after 10 minutes, while the mean thallium indices of meningiomas and gliomas were significantly higher than those of cerebral metastases after 96 hours. The combination of early and superdelayed 201Tl SPECT may be useful in differentiating malignant gliomas from cerebral metastases.

Aged↗
PubMed1996

Usefulness of thallium-201 single photon emission computed tomography to quantify the malignancy grade of brain tumors.

Preoperative thallium-201 (201Tl) single photon emission computed tomography (SPECT) was used to evaluate the histological malignancy in 24 patients with brain tumors. A corrected L/E ratio was calculated based on the ratio of thallium uptake in the tumor on early images versus the tumor in the delayed images (L/E ratio) corrected for thallium uptake in the contralateral cerebral hemisphere. The corrected L/E ratio in benign brain tumors was 0.79 +/- 0.23, significantly different to 1.32 +/- 0.25 in high grade astrocytomas (p < 0.01) and 1.19 +/- 0.05 in metastatic brain tumors (p < 0.01), respectively. The corrected L/E ratio in low grade astrocytomas was 0.64 +/- 0.32, significantly lower than that in high grade astrocytomas (p < 0.01) and metastatic brain tumors (p < 0.05). There was one false positive result among 24 patients using a threshold of 1.0 to separate malignant and benign tumors. 201Tl SPECT using the corrected L/E ratio is effective for determining the malignant viability of tumors.

Adult↗
PubMed2001

Lower-limb vascularization in diabetic patients. Assessment by thallium-201 scanning coupled with exercise myocardial scintigraphy.

OBJECTIVE: To investigate, by thallium-201 scanning, circulation in the muscles of the lower limb (LL) in diabetic patients without clinical peripheral vascular disease but with a high cardiovascular risk profile. RESEARCH DESIGN AND METHODS: A total of 80 diabetic patients (76 patients with type 2 diabetes, mean age 57.3 years, duration of diabetes 13.0 +/- 7.5 years) with more than one additional cardiovascular risk factor but no claudication were investigated. After stress testing, 1.5 MBq/kg thallium-201 was administered to perform myocardial single-photon emission computed tomography followed by LL scanning. Muscle blood flow was considered abnormal if the asymmetry in thallium-201 uptake between the two buttocks and/or thighs and/or calves was > 10%. RESULTS: Muscle perfusion defects were found in 42% of the patients, mainly in the calves. These defects correlated with retinopathy (P = 0.042) and the HbA1c level (P = 0.044). In patients with defects in the buttock and/or thigh, the prevalence of nephropathy and retinopathy was higher than in those with isolated defects in the calf (P = 0.032 and 0.023, respectively). CONCLUSIONS: This study suggests that LL scanning coupled with myocardial scintigraphy is a convenient method of investigating peripheral muscle circulation. Proximal perfusion defects in patients without clinical arterial disease are associated with increased prevalence of retinopathy and nephropathy and, therefore, may be due to microvascular disease of LL muscle. Distal defects may indicate silent macrovascular disease of the LL.

Adult↗
PubMed1981

Thallium ingestion with survival: ineffectiveness of peritoneal dialysis and potassium chloride diuresis.

A 52-year-old man who ingested 20 g of thallium iodide and survived is reported. Therapy included gastrointestinal decontamination, peritoneal dialysis, and potassium chloride diuresis. Peritoneal dialysis removed 4% of the calculated ingested dose in a 24-h period and potassium chloride diuresis 2%, an insignificant amount in light of the ingested dose of thallium. The primary method of treatment of thallium poisoning remains prompt gastrointestinal decontamination.

Diuresis↗
PubMed1982

Thallium intoxication treated with combined hemoperfusion-hemodialysis.

A 32-year-old woman who ingested thallium sulfate was treated with combined hemoperfusion-hemodialysis. Classical therapy, including Prussian Blue, was also administered. The clearance rate of the hemoperfusion and hemodialysis were 139 and 47 mL/min, respectively. The efficiencies of these different methods were compared with each other and with the classical methods. It was concluded that hemoperfusion was the most efficient technique in extracting thallium sulfate. The combined hemoperfusion-hemodialysis procedure is proposed for the treatment of severe intoxications with thallium sulfate.

Adult↗
PubMed1997

[Usefulness of dipyridamole thallium scintigraphy in the diagnosis of coronary artery disease in elderly patients].

Patients suspected of having coronary artery disease (CAD) underwent dipyridamole thallium scintigraphy, exercise electrocardiography, and coronary angiography. Of the 500 patients studied, 163 were at least 65 years old, and 337 were less than 65 years old. Both CAD and multivessel CAD were more common in elderly than in younger patients (81% vs 69%, p < 0.01 for CAD; and 43% vs 26% p < 0.01 for multivessel CAD). In patients without myocardial infarction, the specificity of exercise electrocardiography was lower among elderly patients than among younger patients (52% vs 61%), but the sensitivity was higher (87% vs 75%). In contrast, both the sensitivity and the specificity of dipyridamole thallium scintigraphy were similar in the two age groups (86% vs 87% and 79% vs 74%). Among patients with myocardial infarction and a positive exercise test, reversible defects were equally common in the two age groups (60% vs 58%). The reversible defects were in areas remote from the area of infarction in half of the patients in both groups. Among patients with negative exercise-test results, reversible defects were more common in elderly patients than in younger patients (57% vs 38%). The reversible defects were in the infarcted area in 71% and 79% of these patients, respectively. These results indicate that dipyridamole thallium scintigraphy is a sensitive and specific method for detecting CAD, independent of age. It is particularly useful in identifying myocardial viability in the infarcted area.

Adult↗
PubMed1998

[Assessment of exercise-induced silent myocardial ischemia by dipyridamole thallium imaging. (2). Its significance in Q wave myocardial infarction].

The clinical significance of silent myocardial ischemia (SMI) in the elderly was assessed in 91 patients with Q wave infarction who showed ischemic ST depression during treadmill stress testing, as well as reversible defect (RD) during dipyridamole thallium imaging. They were divided into two groups (47 patients with silent ST depression and 44 patients with painful ST depression) and compared for scintigraphic and coronary arteriographic features, and prognosis. There was no significant difference in age, gender and site of infarction between the two groups. The prevalence of single and double vessel coronary stenosis was higher in patients with SMI (66%) than in those with painful ischemia (p < 0.05). The results of treadmill stress testing showed a longer exercise duration (4.7 +/- 1.7 vs. 4.1 +/- 1.8 min) and higher maximal heart rate (138 +/- 15/vs. 126 +/- 20/min) in patients with SMI than in those with painful ischemia (p < 0.01). Dipyridamole thallium imaging revealed a larger infact (18.8 +/- 9.1 vs. 14.6 +/- 10.2 segments) in patients with SMI than in those with painful ischemia (p < 0.05). The prevalence of RD in the area of infarction was also higher in patients with SMI (74%) than in those with painful ischemia (45%) (p < 0.05). Although a higher proportion of the patients with painful ischemia (42%) underwent CABG or PTCA as their initial therapy, compared with those with SMI (25%) (ns), there was no difference in the cardiac event rate between the two groups who were initially treated medically. Dipyridamole thallium imaging is useful in the assessment of SMI in elderly patients with Q wave myocardial infarction. Those with SMI may have a larger infarct and a higher prevalence of ischemia localized within the infarction than those with painful ischemia.

Aged↗
PubMed1989

Failure of dipyridamole-thallium myocardial imaging to detect severe coronary disease.

Three patients referred for peripheral vascular surgery who died of coronary artery disease complications despite normal dipyridamole-thallium scans are discussed. Although recent literature has shown enthusiasm for this test in this clinical setting, the dipyridamole-thallium scans are not absolute and patients remain at risk for major coronary artery events. Careful clinical screening and awareness of the signs of left main coronary disease on thallium images are important in the evaluation of these patients.

Adult↗
PubMed1978

Myocardial perfusion scanning with thallium--201 for the non-invasive diagnosis of coronary artery disease.

Thallium--201 myocardial perfusion scanning has been evaluated in Australia in patients with coronary artery disease. Myocardial scans reliably detect both acute myocardial infarction and the transient myocardial ischaemia of angina pectoris. The non-invasive nature, ease of study, and the ability to scan patients with conventional cameras makes thallium--201 an attractive additional diagnostic agent for patients with suspected coronary artery disease. Although thallium--201 reliably indicates perfusion defects in the myocardium, its diagnostic use at the moment should be reserved to clarify such diagnostic problems in patients with coronary artery disease which cannot be satisfactorily explained by conventional investigation.

Angina Pectoris↗
PubMed1990

Prognosis in medically stabilized unstable angina: early Holter ST-segment monitoring compared with predischarge exercise thallium tomography.

OBJECTIVE: To assess the relative value of invasive and noninvasive predictors of outcome in patients after unstable angina. DESIGN: Cohort of 54 patients with unstable angina who had 6-month follow-up after stabilization on medical therapy. SETTING: University-based hospital, tertiary referral center. PATIENTS: Consecutive patients with unstable angina whose symptoms resolved while receiving medical therapy. MEASUREMENTS AND MAIN RESULTS: We prospectively compared 24-hour Holter ST-segment monitoring at admission, quantitative exercise thallium tomography, and cardiac catheterization 5 +/- 2 days after admission and analyzed their value for predicting a cardiac event in patients with unstable angina within 6 months. When patients with a favorable outcome (n = 40) were compared with patients with an unfavorable outcome (n = 11) no statistical difference was found in duration of ST shift of 1 mm or more on Holter monitoring (51 +/- 119 min compared with 37 +/- 43 min), exercise duration by the standard Bruce protocol (8.0 +/- 3.6 min compared with 7.9 +/- 3.1 min), exercise-induced ST depression (0.6 +/- 0.9 mm compared with 1.0 +/- 1.0 mm), and contrast left ventricular ejection fraction (70% +/- 10% compared with 69% +/- 15%). Patients with a favorable outcome were distinguished from those with an unfavorable outcome by a higher maximum rate-pressure product (24 x 10(3) +/- 6 x 10(3) compared with 18 x 10(3) +/- 7 x 10(3), P = 0.0025), smaller size of the reversible scintigraphic perfusion defect expressed as a percentage of total myocardium imaged (6% +/- 11% compared with 17% +/- 18%, P = 0.05) and a smaller number of vessels with stenosis of 50% or more (1.1 +/- 1.2 compared with 2.1 +/- 1.0, P = 0.01). On multiple logistic regression analysis, a history of previous myocardial infarction was the most powerful predictor of outcome. In patients without myocardial infarction, reversible exercise thallium perfusion defect size was the only predictor. CONCLUSION: After stabilization of an episode of unstable angina, quantitative tomographic exercise thallium scintigraphy has greater value for risk stratification than Holter ST-segment monitoring, particularly in patients who have not had a previous infarction.

Adult↗
PubMed1999

[Diagnosis of coronary disease: thallium-201 dipyridamole tomoscintigraphy of the myocardium].

OBJECTIVES: Determine the diagnostic performance of thallium-201 myocardial scintigraphy using dipyridamole injection for the detection of coronary heart disease (myocardial ischemia and/or necrosis). Determine for each coronary artery the degree of angiographic stenosis for optimal diagnostic performance. PATIENTS AND METHODS: The study included 309 patients who underwent coronarography within 6 months of the scintigraphy examination. None of the patients experienced a coronary event during this interval. Diagnostic performance of the scintigraphic exploration was compared with angiographic findings (stenosis 70%) used as the gold standard. The degree of angiographic stenosis for optimal scintigraphic performance was determined from the receiver operating characteristic (ROC) curves. RESULTS: The sensitivity of scintigraphy to detect angiographically demonstrated coronary disease was 84% with a specificity of 72%. The positive and negative predictive values were 87% and 66% respectively. Test accuracy was 80%. Sensitivity was better for detecting lesions of the anterior interventricular coronary than for the right coronary or circumflex. In addition, sensitivity varied with the number of vessels involved: 76% for single-vessel disease versus 90% for two- or three-vessel disease. The data analysis also suggested that an angiographic stenosis threshold of 50% provided optimal predictive value for scintigraphy for each of the three vessel territories. An analysis based on maximal stenosis in each patient, notwithstanding the congruency between lesion localization and diseased vessel territories, was found to provide less diagnostic precision. CONCLUSION: Thallium-201 dipyridamole myocardial scintigraphy offers diagnostic performance comparable to that established with thallium-201 scintigraphy performed after exercise alone. Scintigraphic detection of a perfusion defect generally corresponds to an angiographic stenosis of 50%.

Coronary Disease↗
PubMed2000

Prognostic role of stress thallium test in patients with significant coronary artery disease.

OBJECTIVE: The benign outcome of patients with a normal exercise thallium-201 myocardial perfusion study has been well established. The aim of the study was to examine the prognostic implications of normal exercise tomographic thallium images in medically treated patients with angiographic evidence of coronary artery disease (CAD). METHODS: There were 68 patients in Group A with significant angiographic CAD (54 male and 14 female) aged 52 +/- 12 years, 42 had one, 18 had two and eight had three vessel CAD (50% diameter stenosis 1, Group B had 70 patients who had normal coronary arteries at cardiac catheterization. RESULTS: Exercise test was submaximal in 40 (50.82%) patients, ST segment depression during exercise occurred in 28 patients (41.1%) and angina during exercise in 24 patients (35.2%). Majority of patients (76.47%) were on anti-anginal therapy. During a mean follow up of 30 months only two patients had cardiac events in group A patient. One died of cardiac causes and one had non fatal myocardial infarction (event rate 0.96%/year). None of these 2 patients had positive ST response during exercise. In group B only one patient had non-fatal myocardial infarction. CONCLUSION: Medically treated CAD patients including those with multivessel CAD have a benign prognosis in the presence of normal exercise thallium images. These results have long term important implication in management of such patients and cost of health delivery.

Adult↗
PubMedDate not supplied

[Simultaneous assessment of myocardial perfusion and ventricular function using thallium-201 at rest/Tc-99m tetrofosmin at effort with single-photon emission computerized tomography, synchronized with electrocardiogram (synchronized SPECT). Initial experience in Latin America].

UNLABELLED: Gated SPECT is a useful technique to evaluate myocardial perfusion, wall motion abnormalities and wall thickening. There is not published experience in Latin-America using dual isotope rest Thallium-201/stress Tc-99m Tetrofosmin Gated SPECT. METHOD: We studied 27 patients with coronary artery disease. Coronary angiography was performed in all the patients. We used an injection at rest of 3 mCi of Thallium-201 followed by stress and the administration of 15 mCi of Tetrofosmin and Gated SPECT acquisition. Five days after, the patients were injected with 20 mCi of Sestamibi at stress, with a second Gated SPECT acquisition. Perfusion data were analyzed using 20 SPECT segment analysis. To study the wall motion, we divided the heart in 29 segments and every segment was scored using a 4 points scale (3 = normal, 2 = mild hipokinesia, 1 = severe hipokinesia, 0 = akinesia). RESULTS: The perfusion and wall motion segmental score agreement between stress Tc-99m tetrofosmin and stress Tc-99m sestamibi were 97% and 84% respectively. CONCLUSIONS: Rest Thailium-201/stress Tc-99m Tetrofosmin Dual isotope Gated SPECT technique is a good protocol to assess simultaneous myocardial perfusion and wall motion. There is a good agreement of the results with the use of rest Thallium-201/stress Tc-99m Sestamibi Dual isotope Gated SPECT study.

Adult↗
PubMedDate not supplied

Electrothermal atomization of arsenic, antimony and thallium using a graphite atomizer with refractory metal platforms.

The electrothermal atomization of the volatile elements arsenic, antimony and thallium from a refractory metal platform consisting of a tungsten coil and/or a refractory metal foil with the dimensions of a conventional graphite platform was studied. Several combinations of refractory metal platforms were investigated, as follows: W platform; Ta platform; W coil; W coil on a W platform and W coil on a Ta platform. The best combination for these elements as regards both thermal stabilization and sensitivity is the W coil on a Ta platform. Thermal stabilization is also achieved with a W coil on a W platform. The presence of Pd-containing chemical modifier favors the thermal stabilization of the analytes. The sufficient amount is 2 micrograms of Pd. The maximal temperatures of pyrolysis are higher (arsenic, antimony) or equal (thallium) to those when using different chemical modifiers, added as solutions. It may be concluded, that the refractory metal platforms act as "built-in modifiers". They are suitable for the determination of arsenic, antimony and thallium in samples of complex matrix composition where high thermal stability of the analytes during the pyrolysis step is required.

Air Pollutants↗
PubMed2002

[Spectrophotometric study of color reaction of chromogenic reagent 2-hydroxy-5-sulfo-benzenediazoaminoazobenzene(HSDAA) with thallium(III)].

The chromogenic reaction of the 2-hydroxy-5-sulfo-benzenediazoaminoazobenzene(HSDAA) with thallium was studied in this paper. In the presence of Triton X-100 and in ammonia medium of 0.72-0.99 mol.L-1, HSDAA reacts sensitively with thallium (III) to form a red complex with molar radio of 1:2. The apparent molar absorptivity is 1.04 x 10(5) L.mol-1.cm-1 at the maximum absorption wavelength of 516 nm. Beer's law is obeyed in the concentration range of 0-0.8 mg.L-1 Tl(III). Adding NaC4H4O6 and NaCN in the system can improve selectivity of the chromogenic agent greatly. The method has been applied to the direct determination of trace amounts of thallium in sample of synthetic water with satisfactory results.

Azo Compounds↗
PubMed2001

[Color reaction of chromogenic reagent O-hydroxybenzenediazoaminoazobenzene with thallium (III) and its application].

The chromogenic reaction of the O-hydroxybenzenediazoaminoazobenzene (O-HDAA) with thallium was studied in this paper. In the presence of Triton X-100 and SDBS and in ammonia medium of 0.54-1.1 mol.L-1, O-HDAA reacts with thallium (III) to form a stable red complex with molar radio of 1:5. The apparent molar absorptivity is 1.4 x 10(5) L.mol-1.cm-1 at the maximum absorption wavelength of 520 nm. Beer's law is obeyed in the concentration range of 0-600 micrograms.L-1 Tl(III). The method has been applied to the direct determination of trace amounts of thallium in waste water and in geological samples by using polyurethane foam to absorb and separate Tl(III) with satisfactory results.

Color↗
PubMed1992

Functional imaging of peripheral vascular disease: a comparison between exercise whole-body thallium perfusion imaging and contrast arteriography.

Whole-body thallium scintigraphy was used to study leg muscle perfusion in 12 healthy individuals and 31 patients with peripheral vascular disease. Subjects were scanned immediately after exercise and 4 hr later. Buttock, thigh and calf perfusion were measured in terms of fractional uptake relative to whole-body activity, percent change in fractional uptake over 4 hr and interextremity symmetry ratios. The results were compared to contrast arteriography on a region by region basis. The overall sensitivity and specificity of thallium scintigraphy were 80% and 73%, respectively. The results suggest that thallium scintigraphy may provide useful information about the hemodynamic significance of noncritical anatomic lesions.

Angiography↗
PubMed1992

Technetium 99m pentavalent dimercaptosuccinic acid and thallium 201 in detecting recurrent medullary carcinoma of the thyroid.

To compare the effectiveness of thallium chloride 201 and technetium 99m pentavalent dimercaptosuccinic acid in evaluating medullary carcinoma of the thyroid (MCT), eight patients with a history of MCT underwent imaging with both radiopharmaceuticals. Thallium 201 consistently gave superior images, as well as providing one less false-negative scan. Positive scans were obtained in patients with elevation of basal calcitonin levels to more than 1,000 ng/L. All of the patients with positive scans had clinical evidence of local recurrence. Improved imaging with thallium 201 was obtained by early scanning.

Calcitonin↗