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PubMed1980

[Results of quantitative myocardial scintigraphy with thallium-201 at rest and after maximum exercise--critical analysis of predictive value and clinical application (author's transl)].

In 20 normal individuals and 60 patients with CAD, myocardial scintigraphy with thallium-201 was performed after maximum exercise and two hours later at rest. The evaluation of digitized scintigrams was performed quantitatively by means of a 14-halfsegment model. Using ROC analysis, sensitivity and specificity were estimated. Furthermore the predictive value of a thallium scintigram was evaluated by means of the bayesian theorem, comparing the data with coronary angiography and partly also with exercise ventriculography. At a specificity of 90%, sensitivity of scintigraphy for CAD was 97% in 34 patients with previous myocardial infarction and 85% in 26 patients without infarction. Sensitivity for the extent of CAD was 93% for 44 vessels, perfusing infarcted myocardium and 67% for 96 vessels, perfusing non-infarcted myocardium. Sensitivity decreased with increasing extent of CAD and was higher for Cx than for LAD. The predictive value of a positive or negative scintigram was analyzed for different prevalences of CAD. At a low prevalence, e.g. 5%, the predictive value of a pathological scintigram is only 32%, consequently thallium scintigraphy is not applicable as a general screening procedure. At a high prevalence, e.g. 90%, the predictive value of a normal scintigram is only 40%. Therefore thallium scintigraphy seems not to be able to differentiate whether a coronary artery stenosis is hemodynamically significant or not. This was in agreement with the data from exercise cineventriculography. A high predictive value of thallium scintigraphy of about 85% is obtained only in the case of a medium prevalence of CAD, e.g. in asymptomatic patients with pathological Ecg or in patients with atypical angina pectoris. An improvement of the predictive value of myocardial scintigraphy would require other radionuclides than thallium-201, to use higher activities and to allow Ecg-gated myocardial scintigraphy.

Adult↗
PubMed1980

[Myocardial scintigraphy (thallium-201) and electrocardiography at rest and during exercise in angina pectoris. A comparison with coronary angiography (author's transl)].

Ecg (at rest and during exercise) was compared to Thallium-201 myocardial perfusion imaging (at rest and after exercise) in 65 patients with coronary heart disease (myocardial infarction in 53 patients) and angina pectoris. These results were compared to coronary angiography and left ventricular angiography. Group I: (48 patients, comparison of Ecg at rest and Thallium-201 imaging at rest): 33 patients showed agreement of results. In comparison to angiography the 201-Thallium imaging showed less false-negative results than the Ecg as rest. Group II: (23 patients, comparison of Ecg during exercise with Thallium-201 imaging after exercise): 8 patients showed agreement, 15 patients did not. In comparison to angiography the imaging showed better agreement in 20 of 23 patients, the exercise Ecg in 14 of 23 patients. Exercise-Ecg showed false-negative results in 7 patients, Thallium-201 imaging in none. Especially in 1-vessel-disease imaging was superior. Group III: (24 patients, comparison of Ecg at rest and during exercise to 201-Thallium at rest and after exercise): In 19 patients results agreed almost. Because of background-correction imaging is inferior to the Ecg in the apical region. Imaging is superior to the Ecg in the septal and inferior-myocardial regions. Combination of both methods gives best correlations. Sensitivity of Ecg-results is 77% and in imaging 93%.

Adult↗
PubMedDate not supplied

Diagnosis of coronary artery disease using dipyridamole thallium-201 imaging.

Dipyridamole thallium-201 imaging, using single-photon emission computed tomography, was evaluated for its safety and diagnostic efficacy in 109 patients with angiographically documented coronary artery disease and 35 normal subjects. The most common side effects after the intravenous administration of dipyridamole thallium-201 (0.56 mg/kg) included chest pain in 41 patients, dizziness in 20 patients, headache in 16 patients, and ST segment depression > or = 1 mm in 15 patients. Aminophylline was required to reverse the side-effects in 46 patients, and 45 of the 46 patients experienced complete relief of symptoms. Of the 109 patients with coronary artery disease, 104 had abnormal dipyridamole thallium images. The per patient sensitivity was 95%. Of the 35 normal subjects, 27 had normal thallium images. The per patient specificity was 77%. The sensitivity and specificity for the individual vessels were 84% and 87% for the left anterior descending artery, 67% and 97% for the left circumflex artery, and 89% and 85% for the right coronary artery, respectively. Dipyridamole thallium-201 imaging is a relatively safe noninvasive method and is an effective alternative to exercise thallium-201 scintigraphy for the diagnosis of coronary artery disease.

Aged↗
PubMedDate not supplied

Myocardial perfusion scintigraphy in heart transplant recipients with and without allograft atherosclerosis: a comparison of thallium-201 and technetium 99m sestamibi.

Our objectives were to assess the comparative value of thallium-201 and technetium 99m sestamibi for the detection of cardiac allograft atherosclerosis and the left ventricular ejection fraction response to exercise in heart transplant recipients with and without allograft atherosclerosis. Allograft atherosclerosis is the critical factor limiting long-term survival in heart transplant recipients. Annual coronary angiography is invasive and expensive. A noninvasive test to detect allograft atherosclerosis would be clinically useful. Treadmill exercise testing followed by myocardial perfusion single-photon computed tomographic imaging was performed in 25 heart transplant recipients. All patients underwent coronary angiography. Group 1 (13 patients) had angiographic coronary artery disease; group 2 (12 patients) did not. Eighteen patients underwent two exercise tests to equivalent work loads with thallium-201 and technetium 99m sestamibi; seven patients underwent only thallium-201 imaging. First-pass left ventricular ejection fraction was measured during injection of technetium 99m sestamibi. In group 1, 10 of 13 patients had abnormal thallium-201 scans. There was no significant difference in the number of patients who had abnormal thallium-201 (7/10) and technetium 99m sestamibi scans (6/10). Fifty-two percent (12/23) of discordantly scored segments were reversible on thallium-201 and fixed on technetium 99m sestamibi imaging compared with the opposite (0%; 0/23) (p < 0.01). All patients in group 2 had normal perfusion scans. There were no false-positive scans.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Superiority of the reinjection method compared with the redistribution of thallium-201 in the evaluation of reversibility after myocardial infarction].

OBJECTIVE: To assess the relative capacity of thallium-201 reinjection (RI) and redistribution (RD) for detection of reversibility in patients after myocardial infarction. DESIGN: We prospectively studied patients referred to myocardial scintigraphy for viability evaluation with stress, redistribution and reinjection images. METHODS: Patients were studied with thallium-201 SPECT using three imaging acquisitions--stress, redistribution three to four hours later and reinjection 30-60 minutes after a second injection of thallium under nitroglycerin effect. Thallium uptake was classified in a 0 to 4 intensity scale in each of 13 myocardial segments and a score obtained. Reversibility was classified as "definite" if the increase in thallium uptake was > or = 2 in a myocardial segment and as "possible" if the increase was one. PATIENTS: We studied 44 patients with previous myocardial infarction. RESULTS: The perfusion score after stress was 37.3 +/- 6.0, improving to 39.8 +/- 6.7 after redistribution and to 43.6 +/- 7.6 after reinjection (p < 0.02 between RD and RI). RD identified reversibility in 38% and RI in 63% (p < 0.001) of the 232 segments with perfusion defects. RI showed reversibility in 39% (definite in 25% and possible in 14%) of the 137 fixed perfusion defects in RD. For the detection of reversibility RI was superior to RD in all sub-groups analyzed. We found a relationship the degree of collateral circulation in the infarct related artery and the amount of reversibility in the infarcted area. CONCLUSIONS: These data suggest a clear superiority of reinjection over redistribution in thallium-201 scintigraphy for the detection of reversibility of perfusion defects after myocardial infarction, and must probably be considered as a routine procedure for myocardial viability assessment.

Adult↗
PubMed1994

Biokinetics of thallium-201 in normal subjects: comparison between adenosine, dipyridamole, dobutamine and exercise.

UNLABELLED: There are currently four common types of stress used with thallium-201 imaging in the diagnosis of coronary artery disease and risk assessment. The objective of this study was to examine the thallium biokinetics during exercise, adenosine, dipyridamole and dobutamine stress testing in 15 healthy volunteers. METHODS: Each subject underwent planar 201Tl imaging during maximal treadmill exercise testing, adenosine infusion (140 micrograms/kg/min for 6 min), dipyridamole infusion (142 micrograms/kg/min for 4 min) and dobutamine infusion (40 micrograms/kg/min). RESULTS: Absolute myocardial thallium activity was greater after pharmacologic testing than exercise, (p < 0.001 each). Thus, the activity was 505 counts/pixel with adenosine, 491 counts/pixel with dipyridamole, 517 counts/pixel with dobutamine and 409 counts/pixel with exercise. The myocardial thallium clearance was lower with pharmacologic testing than exercise; 9.7%/hr with adenosine, 9.9%/hr with dipyridamole, 11.3%/hr with dobutamine and 13%/hr with exercise (p < 0.01 each). The thallium uptake and clearance in the lung and liver were also greater with pharmacologic stress testing than exercise (p < 0.05). CONCLUSIONS: Thus, thallium biokinetics are different during pharmacologic stress testing with adenosine, dipyridamole and dobutamine than during exercise. Diagnostic criteria for quantitative analysis of myocardial perfusion imaging must therefore be specific for the type of stress used.

Adenosine↗
PubMed1993

Dipyridamole thallium imaging: use in preoperative cardiac risk assessment in vascular surgical patients.

BACKGROUND: The objective of this study was to determine whether routine performance of dipyridamole thallium imaging adds to the power of a careful clinical evaluation in the risk stratification of patients undergoing major vascular surgery. METHODS: In this retrospective study, 115 cases evaluated by dipyridamole thallium imaging before major vascular surgery were reviewed. Patients were assigned to a high-risk cohort if they had a history of congestive heart failure or evidence of previous myocardial infarction. RESULTS: Six (8%) patients from the high-risk cohort developed major cardiovascular complications. Reversible perfusion defects, present in 67% of the high-risk patients, did not predict complications. None of the patients in the low-risk cohort developed complications despite the presence of reversible perfusion defects in 33%. Patients in the high-risk cohort who underwent cardiac catheterization and selective coronary bypass grafting were uniformly free of perioperative complications. The extent and severity of fixed or reversible thallium perfusion did not predict the occurrence of cardiovascular complications. However, three patients were denied surgery following an unacceptable cardiovascular risk assessment based on clinical findings and multiple reversible thallium perfusion defects. CONCLUSION: In low-risk patients, screening with dipyridamole thallium can identify patients with redistribution defects whose risk of perioperative ischemic events can be reduced by intensifying perioperative anti-ischemic management. If the patient is in the high-clinical-risk subgroup, screening with dipyridamole thallium does not identify a cohort with negligible perioperative risk; thus, further evaluation of these patients by cardiac catheterization should be considered.

Aged↗
PubMed1993

[Correlation of regional wall motion and fatty acid metabolism in coronary artery disease, hypertension, and hypertrophic cardiomyopathy: assessment by dual-isotope SPECT with thallium-201 and iodine-123 beta-methyl fatty acid analogue].

In order to investigate the correlation between cardiac fatty acid metabolism and regional wall motion, dual-isotope tomography using thallium-201 and iodine-123 labeled 15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (BMIPP), was performed in 15 patients with coronary artery disease (CAD), hypertension, or hypertrophic cardiomyopathy (HCM). The uptake of thallium and BMIPP was scored and compared with left ventricular regional wall motion assessed by 2-dimensional echocardiography and radionuclide ventriculography. The incidence of a complete agreement of thallium and BMIPP scores was significantly higher in hypertension (64%) and CAD (63%) groups compared to HCM patients (24%), while a lower BMIPP uptake compared to that of thallium (mismatching) was observed more frequently in HCM (65%) than in hypertension (31%) or CAD (33%). Only 3 infarct patients had regional wall motion abnormality which was detected in 20 (95%) of 21 segments with a low BMIPP uptake. Furthermore, compared to thallium perfusion, decreased BMIPP uptake much more corresponded to reduced wall motion in 8 of 11 segments with mismatching. Thus, metabolic abnormality assessed by BMIPP is well associated with asynergy in CAD patients, whereas the discrepancy of fatty acid metabolism and contraction is more dominant in HCM, suggesting that the combined assessment of thallium perfusion, BMIPP uptake, and regional wall motion might contribute to better understanding the pathogenesis of various cardiac disorders.

Adult↗
PubMed1998

Outcome significance of thallium-201 and iodine-123-BMIPP perfusion-metabolism mismatch in preinfarction angina.

UNLABELLED: The relevance of brief antecedent ischemia to preservation of myocyte viability and cardiac function is still controversial in humans. Dysfunctioning but viable myocardium shows impaired fatty acid metabolism despite restored coronary perfusion. We asked whether preinfarction angina might be related to preservation of cell viability and better functional recovery in comparison with impaired fatty acid metabolism. METHODS: Tomographic imagings with thallium and beta-methyl-p-iodophenyl penta-decanoic acid (BMIPP) were performed in 32 patients with first acute myocardial infarction who received primary coronary angioplasty: 20 patients with preexisting angina before infarction (Group A) and 12 without (Group B). Thallium and BMIPP abnormalities were quantified as a severity index by a polar map. Regional function was quantified by ventriculography and followed up. RESULTS: Despite no significant difference in coronary risk factors, cardiac function and angiographic findings, the thallium severity index was significantly lower than that of BMIPP (62+/-45 versus 96+/-59) in Group A but not in Group B (104+/-65 versus 115+/-68); the thallium severity index in Group A was significantly lower than that in Group B, but there was no significant difference in BMIPP abnormality between them. The BMIPP severity index correlated significantly with that of thallium in both groups. However, the regression line in Group A shifted downward and was statistically different compared with that in Group B. Regional function at an acute stage was significantly improved from 107+/-31 to 70+/-31 s.d./chord during follow-up in Group A but not in Group B (109+/-62 versus 106+/-52). The ratio of the thallium severity index to that of BMIPP at an acute stage was significantly related to improved regional wall motion during follow-up in the reperfused patients (y=-53x + 65, r=0.667). CONCLUSION: Preinfarction angina preserves myocyte viability relative to fatty acid metabolism, resulting in augmented perfusion-metabolism mismatch and functional improvement in patients undergoing successful reperfusion, indicating cardioprotective effects of preinfarction angina.

Aged↗
PubMed1998

[Pulmonary uptake of thallium-201 at rest and diastolic function in patients with ischemic cardiopathy and left ventricular dysfunction].

An elevated thallium-201 lung uptake after stress is currently considered a marker of severe coronary artery involvement and related to adverse prognosis. The meaning of this scintigraphic finding on rest thallium-201 images is yet poorly investigated. We compared the thallium-201 lung uptake and the left ventricular diastolic function from mitral Doppler in 24 patients (64 +/- 10 years) with ischemic heart disease and severe left ventricular dysfunction (ejection fraction 28 +/- 10%). All patients underwent a 3-view planar rest-redistribution thallium-201 and 2D-echo studies within 6 days, while clinically stable. The amount of thallium-201 lung uptake was quantified as the ratio (L/H) between the activity in a left lung region of interest (L) and that observed in the left ventricle (H). From mitral Doppler, early (E) and late (A) filling velocities, the E/A ratio and the deceleration time of early filling (DecT) were calculated. An elevated L/H (> or = 0.54) was observed in 9 patients (37%). They showed a lower ejection fraction (20 +/- 4% vs 33 +/- 10% in patients with normal L/H; p < 0.01) and a higher wall motion score index (2.5 +/- 0.4 vs 2.1 +/- 0.4, p < 0.05). A significant inverse linear relation was observed between L/H and the left ventricular ejection fraction (r = -0.70); no significant relation was observed between L/H and left ventricular end-diastolic volumes or wall motion score index. A significant linear relation was also observed between L/H and E/A (r = 0.74; p < 0.001) as well as L/H and DecT (r = -0.61; p < 0.001); an even stronger, inverse, relation was found between L/H and A (r = -0.81; p < 0.001). An abnormal L/H identified 80% of patients with a restrictive filling pattern (specificity 93% and accuracy 88%, respectively). In conclusion, in stable patients with ischemic heart disease and ventricular dysfunction, L/H on rest thallium-201 images is closely correlated with Doppler indexes of left ventricular diastolic filling dynamic; an abnormal L/H is highly predictive of a restrictive filling pattern.

Aged↗
PubMed1996

Synthesis, Properties, and Crystal Structures of Benzene-1,2-dithiolato Complexes of Thallium(I) and -(III).

The syntheses, molecular structures and properties of homoleptic 1,2-S(2)C(6)H(4) complexes of thallium(I) and thallium(III) with four-coordinated metal centers are described. Anaerobic treatment of TlCl, TlNO(3), or Tl(2)CO(3) with solutions of sodium methanolate and 1,2-(HS)(2)C(6)H(4) in methanol gave after metathesis with [NEt(4)]Br yellow solutions of [NEt(4)](2)[{Tl(1,2-(&mgr;-S)(2)C(6)H(4))}(2)] ([NEt(4)](2)1). Yellow single crystals were obtained from saturated acetone solutions at -10 degrees C and the crystal data for [NEt(4)](2)1 are monoclinic, P2(1)/c, with Z = 2, a = 7.440(1) Å, b = 16.373(3) Å, c = 13.201(2) Å, and beta = 97.08(1) degrees. Complex 1(2)(-)(), the first structurally characterized homoleptic ionic thiolate complex of thallium(I), contains rectangular bipyramidal [TlS(4)Tl] cages with the four sulfur atoms defining the equatorial plane and the two thallium atoms in axial positions. The S(2)C(6)H(4) fragments are almost coplanar with the S(4) plane. In the crystal lattice, nearly linear Tl.Tl chains align along the a-axis (offset ca. 3.0 degrees ) with the ligand planes parallel to the bc-plane. Within and between dimers short Tl.Tl distances are observed (Tl.Tl' within a dimeric unit, 3.5116(4) Å; Tl.Tl between dimeric units, 3.9371(3) Å) with the distance between dimeric units being the shortest contact between anions-Tl.S distances between dimeric units are longer than 5.8 Å. Aerobic treatment of TlCl, TlNO(3), or Tl(2)CO(3) with solutions of sodium methanolate and 1,2-(HS)(2)C(6)H(4) in methanol and metathesis with [NEt(4)]Br led to [NEt(4)][Tl(1,2-S(2)C(6)H(4))(2)] ([NEt(4)]2). Yellow single crystals were obtained from saturated acetone solutions at 0 degrees C and the crystal data for [NEt(4)]2 are orthorhombic, Pnn2, with Z = 2, a = 11.449(2) Å, b = 10.060(2) Å, c = 9.950(2) Å. Complex 2(-) is the first homoleptic four-coordinate thiolate of thallium(III) and contains the unusually short Tl-S distance of 2.469(4) Å. In solution, ion pairing results in chemical and magnetic inequivalence of the S(2)C(6)H(4) ligands. Although both preparations employ the reaction of thallium(I) salts with 1,2-(NaS)(2)C(6)H(4) in a 1:2 stoichiometry, complex 1(2)(-) is probably not an intermediate to the formation of 2(-). Exposing anaerobically prepared solutions of 1(2)(-) to air results in a series of color changes in the solution over a 20 min period; however, 2(-) could not be observed by NMR spectroscopy.

Journal Article↗
PubMed2002

Determination of trace amounts of thallium by adsorptive cathodic stripping voltammetry with xylenol orange.

Trace amounts of thallium(I) can be determined using adsorptive cathodic stripping voltammetry in the presence of Xylenol Orange (XO). The reduction current of the thallium(I)-XO complex ion was measured by square-wave cathodic stripping voltammetry. The peak potential was at -0.44 V vs. Ag/AgCl. The effect of various parameters (pH, ligand concentration, accumulation potential and collection time) on the response are discussed. The response was linearly related to the thallium concentration in the range 0.5-110 ng ml(-1) and 110-2000 ng ml(-1). The limit of detection was 0.2 ng ml(-1). The relative standard deviation for the determination of 80 ng ml(-1) thallium was 2.8%. Many common anions and cations did not interfere with the determination of thallium. The interference of lead was reduced by the addition of 0.003 M sodium carbonate. The voltammetric procedure was then successfully applied to the determination of thallium in various complex samples.

Journal Article↗
PubMed1998

[Comparative study of the global left ventricular ejection fraction obtained by ECG gated perfusion MIBI and thallium scintigraphy].

The isotopic LVEF was measured by a planar method with injection of a product visualising the ventricular cavity. Perfusion was assessed by Thallium and sesta MIBI. The investigation of ischaemia and assessment of wall motion in the coronary patient, therefore, requires two isotopic methods. The Cedars Sinai group have developed a programme allowing acquisition of a perfusion tomoscintigraphy in the cardiac cycle after injection of MIBI. This programme automatically detects the endocardial borders and calculates the LVEF. This provides a study of function and perfusion in a single investigation. However, MIBI is not considered by all as a good marker of viability, contrary to Thallium. And the acquisition of Thallium tomography with ECG gating may pose problems because of the low counting statistic. Several authors have therefore studied the possibility of using it for assessing left ventricular function. The authors have then compared LVEF with MIBI and with Thallium in 72 patients. The Thallium LVEF was 33.62% +/- 15.79%; that of MIBI was 32.51% +/- 14.73%. ThalEF = MIBI EF x 1.02 + 0.34 (r = 0.955). The mean of the standard deviation was 1.09. In conclusion, the EF measured by Thallium tomography with ECG gating was closely correlated to that obtained with MIBI. These results suggest that myocardial viability, ischaemia and function may be studied in routine daily practice with a single injection, so improving patient comfort and reducing the costs of the procedures.

Adult↗
PubMed2001

Echo-planar magnetic resonance myocardial perfusion imaging: parametric map analysis and comparison with thallium SPECT.

Magnetic resonance (MR) perfusion FLASH imaging has been used for assessing coronary artery disease (CAD). Echo-planar MR techniques have advantages in speed and in making MR perfusion imaging results more clinically accessible through parametric maps, but have not been previously assessed. We implemented a spin-echo, echo-planar MR technique and applied it at rest and during adenosine stress in 26 patients with CAD and abnormal thallium single-photon-emission computed tomography (SPECT), and analyzed the results by using a newly developed parametric map analysis of time to peak, peak intensity, and slope of contrast washin. The results were compared with the results of conventional visual analysis of the perfusion cine series. For detecting abnormal coronary territories, MR and SPECT were comparable for sensitivity, specificity, and accuracy (thallium, 70%, 78%, and 73%; MR, 79% 83%, and 80%; P = NS). There was good agreement between thallium and MR during stress (kappa = 0.49), but defects were larger by MR (2.4 vs. 3.1 segments for slope; P < 0.01). Additional segments were detected at rest by MR (58 for slope vs. 25 for thallium), which correlated with areas that became abnormal with stress in the thallium (sensitivity, 100%; specificity, 63%). The parametric maps were easier and faster to interpret than review of the original first-pass series of images (chi2 = 10.8; P < 0.04). The diagnostic performance of echo-planar perfusion MR and SPECT was similar, and combining the results with parametric mapping was useful for interpretation and considerably improved data display for clinical interpretation. MR, however, was faster and yielded images of higher resolution with no radiation burden. In multislice mode, these new MR techniques may have clinical value.

Aged↗
PubMed1996

Thallium perfusion defects predict subsequent cardiac dysfunction in patients with systemic sclerosis.

OBJECTIVE: To determine the significance of thallium perfusion defects in patients with systemic sclerosis (SSc). METHODS: This is a followup study of a series of 48 SSc patients who underwent thallium perfusion scans in the early 1980s. Their cardiac history and survival information over the last 10 years were obtained as part of the Pittsburgh Databank's yearly evaluation. We determined the frequency of subsequent development of arrhythmias requiring treatment or of congestive heart failure through patient and physician information. RESULTS: Patients with larger thallium perfusion defects had a significantly increased risk of developing subsequent cardiac events or death. The size of the initial thallium defect was the best predictor of later adverse events compared with other disease-related features, in a logistic regression analysis. CONCLUSION: We conclude that patients with SSc who have significant thallium perfusion defects are at a significantly increased risk of developing subsequent cardiac disease or death.

Female↗
PubMed1989

Sequential multivessel coronary angioplasty assessed by thallium-201 tomography.

In 11 patients with multivessel coronary artery disease, SPECT thallium-201 imaging was performed prior to and within 3 days after each of two sequential percutaneous transluminal coronary angioplasties on separate days designed to achieve total revascularization. Thallium-201 SPECT was analyzed quantitatively, and an ischemic score for the vascular bed(s) supplied by the dilated vessel(s) was derived. For the vessels dilated during the first procedure the mean diameter stenosis was 80 +/- 8%, reduced to 27 +/- 9%. For the second procedure mean stenosis was reduced from 67 +/- 10% to 26 +/- 6%. For the two procedures, the mean thallium scores decreased from 298 +/- 225 to 115 +/- 130 (P less than .001) and from 135 +/- 129 to 46 +/- 60 (P less than .001), respectively. Of 10 patients with abnormal thallium-201 SPECT prior to angioplasty, nine improved after the first procedure, and seven improved further following the second procedure. Thus, utilizing staged angioplasty with a strategy of dilating the most severe lesion first, thallium-201 SPECT documented progressive improvement in myocardial perfusion.

Angioplasty, Balloon, Coronary↗
PubMed1993

Minimal residual coronary obstructions in patients who suffered a first myocardial infarction. A prospective study comparing coronary angiography and exercise thallium scintigraphy.

The purpose of the present study was to correlate the presence of minimal coronary obstruction (< or = 50%) assessed by coronary angiography with the presence of myocardial scar and ischemia detected by thallium-201 myocardial perfusion imaging. The study included 83 consecutive patients (74 men and 9 women) with a mean age 55.4 +/- 8.5 years who suffered a first myocardial infarction and did not undergo thrombolytic therapy. In all patients, coronary angiography, left ventriculography, and exercise thallium-201 tomographic scintigraphy were performed within 3 to 5 months of the myocardial infarction. Coronary arteriograms showed minimal residual obstructions in 37 (45%) patients. Of a total of 54 patients with < or = 50% obstruction, 18 showed persistent defects and 22 reversible defects on thallium scintigrams. The present study showing estimated angiographic stenosis of < or = 50% as being responsible either for myocardial scar or myocardial ischemia on postexercise thallium scintigrams leads us to conclude that percent value of stenosis does not accurately predict the pathophysiologic significance of coronary atherosclerotic lesions in patients who suffer a myocardial infarction. After a first myocardial infarction, coronary angiographies and thallium-201 scintigrams are complementary for an optimal treatment strategy for selected subsets of patients.

Adult↗
PubMedDate not supplied

Thallium-201 per rectum for the diagnosis of cirrhosis in patients with asymptomatic chronic hepatitis.

In normal subjects, thallium-201, administered per rectum, is taken up mainly by the liver (heart/liver ratio in normal subjects: 0.04 to 0.12). It has been claimed that an increased heart/liver ratio is suggestive of portal-caval shunting and portal hypertension. To evaluate the possibility of using thallium-201 as a test to diagnose cirrhosis, we administered this substance per rectum to 33 patients with biochemical evidence, but no clinical symptoms, of liver disease. Laparoscopy and liver biopsy revealed chronic active hepatitis without cirrhosis in 18 patients, and chronic active hepatitis with cirrhosis in the others. The results of conventional liver function tests were similar in both groups. A significant difference, however, was found between the means of fasting serum bile acid concentrations (9.8 +/- 3.2 and 18.3 +/- 4.2 microM per liter) in chronic active hepatitis without cirrhosis and cirrhotic patients, and between the means of the heart/liver ratios 20 min after thallium-201 administration (heart/liver: 0.09 +/- 0.03 and 0.54 +/- 0.13, respectively). Unlike the serum bile acid concentration which gave some overlapping values, the thallium-201 test clearly distinguished the chronic active hepatitis without cirrhosis group from the cirrhotics. In the cirrhotic group, there was a significant correlation between the heart/liver ratio and signs of portal hypertension such as esophageal varices, increased diameter of the vena porta and hypersplenism. The thallium-201 test is therefore useful in discriminating between chronic active hepatitis with and without cirrhosis in clinically asymptomatic subjects with biochemical evidence of moderate liver function impairment. A heart/liver uptake ratio much higher than normal (above 0.30) strongly suggests the development of hepatic cirrhosis.

Administration, Rectal↗