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PubMed1999

BMIPP compared with thallium redistribution.

I-123 labeled methyl-branched fatty acid, BMIPP, has been used mainly in Europe and Japan for the evaluation of various cardiac diseases. BMIPP uptake abnormality is usually more prominent tan perfusion, representing discordant BMIPP uptake less than thallium. This finding is observed in various cardiac disease conditions such as acute myocardial infarction, stable and unstable angina, hypertrophic and dilated cardiomyopathies. Many BMIPP studies combined stress thallium imaging in patients with coronary artery disease and hypertrophic cardiomyopathy demonstrated that such discordant BMIPP uptake less than thallium is related to stress-induced ischemia as evidenced by reversible thallium defect after exercise. BMIPP imaging is able to detect metabolic alteration in the heart which is not available by perfusion imaging alone.

Angina, Unstable↗
PubMed1997

A case of localized retinal damage in thallium poisoning.

PURPOSE: To determine the cause of visual impairment and to document the late eye disturbances in a case of thallium poisoning. PATIENT: A 44-year-old woman presented with a history of repeated attacks of complete alopecia over a period of several months, diffuse pain in both legs, transient gastrointestinal disturbances, abasia with a progressive paraparesis, paresthesia in the fingertips, and polyneuropathy. She complained of slowly progressive visual deterioration in both eyes which began about six months after the first attack of alopecia. The optic discs showed distinct signs of temporal atrophy together with a deep temporal excavation. The Goldmann perimetry revealed an absolute central scotoma. Traces of thallium were found in the urine and in the serum. The district attorney later discovered that her husband had been trying to poison her with thallium. METHODS: The clinical and electrophysiological examinations included visual evoked potentials (VEP) and electroretinography (flash ERG, multifocal ERG and pattern ERG). RESULTS: The VEP showed a reduction in amplitude and a prolonged latency indicating a conduction block. The pattern ERG was initially normal. At a follow-up examination 6 years later, a slight amplitude reduction in the pattern ERG was found. The multifocal ERG showed a diminished amplitude in the center of the retina (up to +/- 10 degrees visual angle). CONCLUSIONS: The electrophysiological investigations in our patient--who had an optic atrophy--indicated a conduction block of the retinal nerve fibers (VEP) and an additional lesion at or before the retinal bipolar cells (multifocal ERG), localized in the central +/- 10 degrees. These findings suggest that thallium poisoning can lead to a combined lesion of the retinal nerve fibers and the neural retina.

Adult↗
PubMed1998

Predicting chemotherapeutic response to small-cell lung cancer of platinum compounds by thallium-201 single-photon emission computerized tomography.

Thallium-201 single-photon emission computerized tomography (SPECT) was used to clarify the relationship between 201Tl uptake and the response in chemotherapy to platinum compounds in 21 patients with small-cell lung cancer. 201Tl-SPECT scans were obtained twice: at 15 min (early scan) and 120 min (delayed scan) after an intravenous injection of 111 MBq (3 mCi) of thallium-201 chloride. We obtained the uptake ratio from each scan and calculated the retention index:uptake ratio = region of interest uptake/contralateral normal lung uptake; retention index = (delayed ratio - early ratio)/early ratio. After 201Tl scintigraphy, 12 patients received chemotherapy consisting of platinum compounds and nine were treated with chemoradiation. Among patients receiving only chemotherapy, the retention index correlated with the responses to chemotherapy. In an in vitro study, ouabain, an inhibitor of the Na,K-ATPase pump, reduced sensitivity to cisplatin and inhibited intracellular thallium uptake in the small-cell lung cancer cell line. These studies suggest that 201Tl-SPECT is a useful indicator of response to chemotherapy with platinum compounds in small-cell lung cancer, and that Na,K-ATPase is commonly involved in transporting both thallium and platinum compounds into cancer cells.

Aged↗
PubMed2003

Validation of R wave voltage endomyocardial mapping to assess myocardial fibrosis: comparison with thallium and dobutamine echocardiography in a swine model.

The first aim of this study was to validate R wave voltage values measured with a catheter-based three-dimensional mapping system (NOGA, Biosense) against myocardial fibrosis in a swine model of ameroid placement. The second aim was to correlate the UPV maps with thallium uptake and low-dose dobutamine echocardiography. The electromechanical catheter mapping system can be used to guide endomyocardial laser therapy and direct gene delivery to the myocardium. The accuracy of R wave voltage in identifying myocardial fibrosis and its comparison with other imaging technologies against histopathology has not been fully investigated in an animal model. Ameroid constrictors were placed on 24 vessels in 14 swine. Wall motion abnormalities by echocardiography were detected in distribution of the constrictors at 22 +/- 10 days. Animals underwent rest and delayed thallium imaging, low-dose dobutamine echocardiography, and R wave voltage mapping. Animals were sacrificed, hearts were removed, 4-micron slices were stained, and fibrosis was quantified. Five control animals were studied to obtain segment normalization. There was significant agreement between each imaging modality and fibrosis by chi-square analysis. The correlation for segment normalized thallium uptake and segment normalized UPV score versus fibrosis were both significant (P < 0.001) with an r2 value of 0.362 vs. thallium, and r2 = 0.445 vs. UPV. The correlation was improved using log of UPV vs. fibrosis (r = 0.532). These results help validate R wave voltage mapping as an imaging technique to identify myocardial fibrosis.

Animals↗
PubMed2000

Dobutamine stress echocardiography and thallium-201 SPECT for detecting ischaemic dilated cardiomyopathy in patients with heart failure.

AIMS: A diagnosis of ischaemic aetiology of a dilated cardiomyopathy has important therapeutic and prognostic implications. In such patients, abnormal ECG and atypical symptoms limit the usefulness of standard ECG-ergometry in detecting myocardial ischaemia. To assess the values of high-dose dobutamine stress echocardiography and of Thallium-201 SPECT (exercise-reinjection-rest protocol) in differentiating between ischaemic and non-ischaemic dilated cardiomyopathy, 37 patients with suspected myocardial ischemia, low ventricular ejection fraction (23 +/- 5%) and heart failure were studied. METHODS AND RESULTS: Coronary artery disease was defined as >50% coronary stenosis in at least one coronary artery. By dobutamine stress echocardiography, ischaemic dilated cardiomyopathy was considered present when either an ischaemic response (biphasic response or direct deterioration) or a scar (fixed dyssynergy) was documented in at least two segments. By Thallium-201 SPECT, severe perfusion defects, either reversible (ischaemia) or fixed (scar), in at least two segments were considered markers of ischaemic dilated cardiomyopathy. Twenty-three patients had ischaemic dilated cardiomyopathy, while 14 had normal coronary arteries. The presence of myocardial ischaemia and/or scar by dobutamine stress echocardiography identified patients with ischaemic dilated cardiomyopathy with a sensitivity of 100% and a specificity of 86%. The sensitivity of Thallium-201 SPECT was 92%, its specificity was 69%. Three of the four false positive results occurred in patients with left bundle branch block. Thirty-two patients were concordantly classified by the two techniques (agreement=86%, k=0.73). CONCLUSION: Both dobutamine stress echocardiography and Thallium-201 SPECT are sensitive techniques for detecting the ischaemic aetiology of dilated cardiomyopathy. The specificity is lower, particularly by SPECT, when left ventricular branch block is present.

Cardiomyopathy, Dilated↗
PubMed1975

Idiopathic hypertrophic subaortic stenosis: detection by thallium 201 myocardial perfusion imaging.

To determine whether thallium 201 myocardial imaging could be used to detect hypertrophic cardiomyopathy, 10 patients with idiopathic hypertrophic subaortic stenosis were studied. Asymmetric septal hypertrophy, an anatomic marker for this disease, was evident on thallium scans in the patients with idiopathic hypertrophic subaortic stenosis, with a ratio of septum to left ventricular free wall of 1.7 cm compared to 1.0 cm in eight normal volunteers, and 1.0 cm in eight patients with concentric left ventricular hypertrophy. Patients with hypertrophic cardiomyopathy also demonstrated apical ventricular wall thickening, and a thicker posterior ventricular free wall in the obstructive in contrast to the nonobstructive form of this disease. Thallium scans of three patients with pulmonary hypertension and secondary asymmetric septal hypertrophy were distinguished from idiopathic hypertrophic subaortic stenosis by marked right ventricular wall thickening. Thus, thallium 201 myocardial perfusion imaging provides a noninvasive method for detection and evaluation of idiopathic hypertrophic subaortic stenosis.

Cardiomyopathy, Hypertrophic↗
PubMed1984

Dipyridamole-thallium-201 scintigraphy in the prediction of future cardiac events after acute myocardial infarction.

To evaluate the safety and usefulness of serial thallium scanning immediately after intravenous dipyridamole, we studied 51 patients recovering from acute myocardial infarction. Eight patients experienced angina during the procedure, but there were no serious complications. Patients were followed for a mean period of 19 months after hospital discharge. Eleven of 12 patients who died during follow-up or had another infarction had shown transient defects (redistribution) on their predischarge scan, as had 22 of the 24 patients who needed readmission for management of angina. Among all the other clinical or scintigraphic criteria tested, the presence of redistribution on the dipyridamole-thallium scan was the only significant predictor of these serious cardiac events. Twenty-six patients were also given a submaximal exercise test before discharge, of whom 13 subsequently had serious cardiac events. The exercise test had been positive in only 6 of these 13 patients, whereas the dipyridamole-thallium scan had shown a redistribution pattern in 12 (P less than 0.001). We conclude from this preliminary study that dipyridamole-thallium scintigraphy after myocardial infraction is relatively safe. It appears to be a more sensitive predictor of subsequent cardiac events than a submaximal exercise test and may therefore prove useful in evaluating patients after recovery from a myocardial infarction.

Aged↗
PubMed1999

Cytogenetic investigation of thallium-poisoned people: pilot study.

Thirteen blood samples of thallium-poisoned people were cytogenetically investigated. The thallium concentration in blood varied from 25 to 2700 microg/L. The mean frequency of chromosomal aberrations in the poisoned group significantly exceeded our control level (7.08+/--2.19% and 2.03+/--0.25, p<.001). The rate of single fragments was significantly higher in poisoned group (7.77+/-2.68% and 1.59+/-0.23%, p<.001) while the frequencies of other types of chromosomal aberrations were similar in both groups. It is possible that thallium is an S-dependent clastogenic agent because the majority of the structural aberrations are of the chromatid type. Irrespective of mechanisms, damage to genetic material was revealed in thallium-poisoned people.

Analysis of Variance↗
PubMedDate not supplied

Thallium in foods and the diet.

Sources of thallium in food and normal levels of thallium in food are discussed. Information on dietary intakes of thallium in the UK is presented, current intakes are estimated to be about 0.005 mg/day. The dietary intake and published data on urinary excretion are consistent. It is considered that brassicae are likely to be the main source of dietary exposure to thallium in food produced on contaminated land.

Brassica↗
PubMed2005

Quantitative thallium-201 scintigraphy in childhood osteosarcoma: Comparison with technetuim-99m MDP and magnetic resonance imaging in the evaluation of chemotherapeutic response.

The aim of this study was to assess early (15 min) and late 2 h) thallium-201 (201Tl) uptake in children with osteosarcoma and to compare these findings with magnetic resonance imaging (MRI) and technetium-99m methylenediphosphonate (99mTc MDP), with emphasis on evaluating tumor viability before and after chemotherapy. Fifteen patients with biopsy-proven osteosarcoma received standard preoperative chemotherapy with a combination of cisplatin, Adriamycin, and high-dose methotrexate. Their ages ranged between 7 and 18 years (median 14.5 years). All patients had 201Tl, 99mTc MDP, and MRI studies. Thallium scintigraphy was performed at 15 min and 2 h after IV injection of 92 MBq of thallium. Thallium uptake ratio was calculated by dividing the count density of the lesion (L) by that of the controlateral normal (N) area. The percent reduction of 201Tl uptake ratio (alteration ratio) was calculated by [100x(prechemotherapy L/N-postchemotherapy L/N)/prechemotherapy L/N]. Pathologic changes were graded on the basis of % tumor necrosis as defined histologically. Scintigraphic comparisons demonstrated a high-degree of correlation with late 201Tl alteration ration and poor correlation with both early 201Tl and 99mTc MDP alteration ratios. Late 201Tl images were superior to early 201Tl, 99mTc MDP, and MRI in predicting tumor response to chemotherapy as determined by % tumor necrosis (p<.01). The authors found that late 201Tl was an accurate test for evaluating the response to specific therapeutic regimens and it can be useful planning surgery or choosing alternative chemotherapeutic regimens.

Adolescent↗
PubMed1987

Gated thallium scintigraphy in patients with coronary artery disease: an improved planar imaging technique.

The use of thallium scanning in the assessment of myocardial perfusion is well established. However, myocardial contraction leads to significant blurring of standard static images. By using electrocardiographic gating and a high sensitivity collimator, multiple view gated scans can be acquired prior to thallium redistribution. Reporting of these images on cine loop display in 100 consecutive patients undergoing coronary arteriography and 14 volunteers results in improved visual assessment of regional myocardial perfusion (with reduced interobserver variability) and, in addition, yields useful and accurate information on left ventricular function. The combination of better assessment of perfusion and information on wall motion results in improved detection of patients with significant coronary disease with no loss of specificity when compared with static images. Predictive accuracy improves from 85% to 94% with gated imaging. Gated thallium scanning could be readily applied in most centres using thallium at no extra cost and with improved predictive accuracy in the non-invasive detection of significant coronary disease.

Coronary Disease↗
PubMed1992

A negative thallium (+/- dipyridamole) stress test excludes significant obstructive epicardial coronary artery disease in hypertensive patients.

The operating characteristics of thallium stress testing for detection of significant epicardial coronary artery disease (CAD) in hypertensive subjects with chest pain or electrocardiographic (ECG) ischemia have not been previously defined. This becomes important because of the high prevalence of both hypertensive heart disease and CAD. Ninety-two hypertensives with a history of typical or atypical chest pain or ECG myocardial ischemia underwent coronary arteriography, 2D-guided echocardiography, and thallium-201 stress testing, combined with intravenous dipyridamole if the rate-pressure product was less than 20,000. Patients with myocardial infarction, prior revascularization procedure, valvular heart disease, and chronic ethanol abuse were excluded. The mean age was 54.8 +/- 9.9 years with 55% blacks and 46% women. Eighteen patients (19.6%) had significant (greater than or equal to 50% luminal diameter narrowing) epicardial CAD at catheterization, of whom 17 had positive thallium scans. Overall, there were 17 true positives, 47 true negatives, 27 false positives, and one false negative resulting in 94.4 +/- 5.4% sensitivity (95% confidence limits [95% CL] 71 to 100%), 63.5 +/- 5.6% specificity (95% CL 51 to 74%), 38.6 +/- 7.3% positive predictive value (95% CL 25 to 54%), 97.9 +/- 2.1% negative predictive value (95% CL 88 to 100%), and 69.6 +/- 4.8% overall accuracy (95% CL 59 to 79%). For hypertensive patients with chest pain or ECG myocardial ischemia, the high sensitivity and negative predictive value and low false negative rate support the role of thallium stress testing +/- dipyridamole as an exclusion test for significant CAD.

Adult↗
PubMed1993

Increased expression of the lactate dehydrogenase M subunit in myocardial regions with decreased thallium uptake.

OBJECTIVE: In ischaemic heart disease, the heart muscle is subjected to repeated episodes of regional ischaemia or to a constant underperfusion. The purpose of the present investigation was to study the myocardial metabolic adaptation to this stress. METHODS: Eighteen male patients with ischaemic heart disease were studied by biopsies taken from the left ventricular septum during bypass surgery. Citrate synthase, total lactate dehydrogenase and its H and M subunits, coenzyme Q10, and myoglobin were determined in all biopsies. Concentrations of ATP, ADP, and AMP were determined and energy charge calculated in the biopsies from the patients with ischaemic heart disease. Biopsies from the septal region of hearts obtained from brain dead kidney and liver donors were used as reference and preoperative myocardial thallium scintigraphy was performed in the patients with ischaemic heart disease to relate the myocardial biochemical markers to thallium uptake at the biopsy site. RESULTS: Myocardial activities of citrate synthase as well as contents of coenzyme Q10 and myoglobin in patients with ischaemic heart disease were not different from those of the reference group, and no linear relation was found between these three markers on the one hand and thallium uptake on the other. The energy charge was directly related and the M subunit of lactate dehydrogenase inversely related to the thallium uptake. CONCLUSION: The results suggest an absence of adaptation to ischaemia in terms of increased myocardial oxidative capacity and O2 transport and storage capacity. Furthermore, it is indicated that a stressed energy metabolism with increasing severity of ischaemic heart disease enhances anaerobic metabolism and induces a shift in myocardial lactate dehydrogenase subunit fractions.

Adolescent↗
PubMed1993

Coronary artery disease after heart transplantation: non-invasive evaluation with exercise thallium scintigraphy.

In order to assess the value of exercise thallium scintigraphy for the detection and prognosis of graft coronary artery disease, 50 heart transplant patients (mean age 46.7 +/- 11.5 years) were studied within 48 h of their scheduled yearly coronary angiography and subsequently followed up for a mean of 13 +/- 3 months. Angiography revealed normal coronary arteries in 35 patients, and coronary artery disease in 15 (two with type A lesions, seven with type B lesions and six with both). Seven patients had one or more stenoses > or = 50%. Exercise thallium scintigraphy was negative in all patients with normal coronary arteries (100% specificity), and abnormal in 10 of 15 patients with coronary artery disease (67% sensitivity). Fixed defects were seen in six cases, transient defects in two and both in two; the results of the test were abnormal in all seven patients with > or = 50% lesions. During follow-up, none of the patients with a normal exercise thallium scintigraphy experienced any cardiac event; in the group with abnormal results, four cardiac events occurred. Although further studies are needed to confirm these results, exercise thallium scintigraphy seems to be useful in evaluating post-transplant coronary artery disease: it is accurate in detecting the most severe stenoses and provides some prognostic information.

Adult↗
PubMedDate not supplied

Thallium elimination kinetics in acute thallotoxicosis.

This is a presentation of an acute fatal case of thallotoxicosis. The symptomatology of this ingestion and the absorption, distribution, and excretion of thallium will be discussed. Reliable pharmacokinetic information, monitoring the disappearance of thallium, will be correlated to the clinical events. This paper makes a contribution to the toxicology of thallotoxicosis in terms of kinetics of thallium and pharmacokinetics in acute ingestion. Values obtained on multiple, sequential, whole blood concentration, urine, fecal and bile contents, and eventually coronary sinus blood and organ analysis obtained at necropsy of brain, kidney, liver, and lungs and residual material obtained from the ileum and colon, are reported. The kinetics of elimination were determined from the values previously mentioned. Prussian Blue was found to be ineffective in preserving life in this case, although increased urine and fecal excretion of thallium occurred with its use. Kayexalate did not appear to contribute to the therapy in this case. Earlier and more aggressive treatment is recommended. Kinetic events in relation to neurological effects, as well as other signs and symptoms, are discussed. The histological necropsy findings from this fatal ingestion will also be presented. Recommendations in clinical, toxicological, and therapeutic areas are made.

Adult↗
PubMed1996

Tomographic myocardial imaging with technetium-99m tetrofosmin. Comparison with tetrofosmin and thallium planar imaging and with angiography.

Technetium-99m tetrofosmin is a new myocardial imaging agent with improved handling and kinetic characteristics. The purpose of this study was to compare the ability of planar and SPECT Tc-99m tetrofosmin imaging with Thallium-201 planar data to detect coronary artery disease and individual vessel lesions ( > 50% diameter stenosis). Seventy-two patients with definite or suspected coronary artery disease were included. Sixty-three had angiographic evidence of coronary artery disease, among whom 42 had had a previous myocardial infarction, while 21 had not. The total number of diseased arteries was 111. Patients underwent symptom-limited treadmill or bicycle exercise to similar endpoints. Thallium and tetrofosmin images were analysed separately by consensus reading. Interpretation was made for five standard anatomical regions (anterior, septal, inferior, lateral and apex), classified into four categories (normal, reversible, fixed and mixed defects). Sensitivity and specificity to detect coronary artery disease were 71% and 78% for Thallium-201 vs 68% and 78% for tetrofosmin by planar imaging, and 87% and 89% for tetrofosmin by SPECT. The improved sensitivity of SPECT was confirmed both in patients with and without previous myocardial infarction. The sensitivity to detect individual vessel lesions was improved by SPECT (59% tetrofosmin SPECT vs 50% thallium planar and 51% tetrofosmin planar). Individual vessel lesion detection by SPECT was 50% for the left anterior descending coronary artery, 42% for the left circumflex and 86% for the right coronary artery. This study confirms the value of technetium-99m tetrofosmin as a myocardial imaging agent. Improvements in diagnosis and in evaluating extent of disease can be expected from using SPECT.

Adult↗
PubMed1994

Thallium perfusion and myocardial hypertrophy in transplanted heart recipients with normal or near-normal coronary arteriograms.

In patients with hypertrophic cardiomyopathy or systemic hypertension, exercise thallium perfusion defects have been observed but without significant angiographic stenoses. Hypertension and myocardial hypertrophy are common in transplanted heart recipients, and the aim of this study was to determine if exercise thallium scintigraphy false-positives are frequent in transplanted heart recipients. Thirty-four transplanted heart recipients were evaluated by exercise thallium single emission computed tomography and subsequently had a normal or near normal coronary arteriogram. At the time of the exercise, the patients (28 men and six women) had a mean age of 48.9 +/- 12 years and 29 had been previously treated for systemic hypertension. The mean duration between transplantation and the exercise test was 31.6 +/- 13 months. In all patients left ventricular mass was obtained by echocardiography within 3 months of thallium 201 SPECT and was > or = 130 g.m-2 in nine males and > or = 110 g.m-2 in four females. M-mode septal + posterior end-diastolic thickness was > 23 mm in 14 patients, all of whom had been previously treated for systemic hypertension. These patients were older and endured a longer period during which the heart was kept cold but ischaemic before being grafted ('cold ischaemia') but a shorter exercise duration than patients without left ventricular hypertrophy. During exercise testing, 26 of 34 patients achieved at least 80% of their maximal predicted heart rate and two developed significant ECG changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Recovery of left ventricular function after myocardial infarction can be predicted immediately after thrombolysis by semiquantitative intracoronary thallium and technetium pyrophosphate scintigraphy.

The accuracy with which intracoronary thallium and technetium pyrophosphate scintigraphy during intracoronary thrombolysis predicts myocardial salvage was studied in 58 patients with acute myocardial infarction by comparing the acute scintigraphic findings with subsequent left ventricular function. Scintigrams obtained before and immediately after thrombolysis were interpreted by three independent observers using a scoring system. Regional wall motion in the infarct area was determined from left ventricular (LV) cine angiograms using the center-line method. Patients with mild hypokinesis (hypokinesis less than or equal to -2 SD from normal) could be distinguished from those with severe hypokinesis (hypokinesis greater than -2 SD) using the prethrombolysis thallium score with an accuracy of 83%. Accuracy using the post-thrombolysis score was 76%. When the post-thrombolysis thallium and technetium pyrophosphate scores were combined, differentiation was possible in 91% of all patients studied, and in 100% of patients with anterior myocardial infarction. Thus, analysis of combined thallium and technetium pyrophosphate scintigraphy accurately predicts recovery of LV function after thrombolysis and may be helpful in deciding whether acute percutaneous transluminal coronary angioplasty or bypass surgery should be performed after thrombolysis.

Cardiac Output↗