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1

Evaluation of dilated cardiomyopathy by 201Tl myocardial single photon emission computed tomography  

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To estimate dilated cardiomyopathy (DCM)morphologically and quantitatively, 201Tl myocardial single photon emission computed tomography (SPECT) was performed in 14 DCM and 5 normal cases. Using a rotating dual-gamma camera system, resting SPECT data were collected for 6 minutes. Quantitative analysis of clinical cases was based on phantom studies. (I) Morphological features Marked spherical left ventricular (LV) dilatation (14/14), localized-diffuse low uptake or defect (12/14), and right ventricular visualization (6/14) were characteristic features in DCM. Differentiation of DCM from ischemic heart disease by SPECT was possible through the feature indicating disproportionately large LV cavity to defect size or degree. (II) Quantitative analysis When DCM was compared with normal control (n-5), following 3 features were impressive; 1) DCM was significantly higher in LV myocardial 201Tl uptake ratio and LV volume than normal control. (4.8+-1.3%: 3.3+-0.2%, p201Tl uptake ratio of unit volume (1 ml) than normal control. 3) DCM was significantly lower in mean myocardial count/mean lung count.ratio than normal control. Thus we concluded that 201Tl myocardial SPECT was useful non-invasive technique for diagnosis of DCM and was with fairly well correlation between morphology and quantitative estimations. Furthermore, this qutitative estimations. Furthermore, this quantitative method appears to be applicable for estimation of other cardiac disease. (author)

2

Assessment of left ventricular function using 201Tl electrocardiogram-gated myocardial single photon emission computed tomography  

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Advances in computed tomography (CT) technology make it possible to obtain left ventricular wall motion using 3D reconstruction. In this study, we compared the images obtained from CT and 201Tl electrocardiogram (ECG) gated single photon emission computed tomography (SPECT). In 20 patients with ischemic heart disease, we performed 201Tl ECG gated SPECT (GE Healthcare Millennium VG) and ECG gated CT (Philips Medical Systems Brilliance iCT) to evaluate of left ventricular wall motion during the resting phase. In SPECT, left ventricular images were reconstructed using quantitative gated SPECT (QGS) software. In CT, the images were reconstructed using Virtual Place (AZE Software). The left ventricle was classified into five regions (anterior, lateral, inferior, septal, and apical). The amplitude of the wall motion was classified into five grades according to AHA classification. The values of the wall motion were separately checked by two radiographers. Assessment of left ventricular function myocardial wall movement using the three-dimensional movie display with ECG gated myocardial SPECT data was in agreement with the evaluation by cardiac CT inspection, and corresponded with wall motion in 88 of all 100 segments. SPECT analysis has the same quantity as that of obtained from CT for evaluation of left ventricular wall motion. (author)

3

Effects of smoking on myocardial injury in patients with conservatively treated acute myocardial infarction. A study with resting {sup 123}I-15-iodophenyl 3-methyl pentadecanoic acid/{sup 201}Tl myocardial single photon emission computed tomography  

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Many reports have demonstrated that smokers who have suffered an acute myocardial infarction (AMI) have a better prognosis than nonsmokers. The present study investigated the effects of current smoking on myocardial injury with resting {sup 123}I-15-iodophenyl 3-methyl pentadecanoic acid (BMIPP)/{sup 201}Tl myocardial single photon emission computed tomography in 103 patients with conservatively treated AMI. The left ventricular myocardium was divided into 9 segments and BMIPP and {sup 201}Tl defects were scored using a 5-point grading system (0=normal and 4=no uptake). The sum of the defect scores was defined as the total defect score. There was no significant difference in either the baseline severity of the coronary artery discase or the total defect scores for BMIPP and {sup 201}Tl between the current smoker and nonsmoker groups. The difference between the total defect scores for BMIPP and {sup 201}Tl tended to be larger in the current smoker group than in the nonsmoker group (2.0{+-}1.9 vs 1.3{+-}1.6, p=0.056). Forty-one (53%) of 77 patients in the current smoker group exhibited a BMIPP/{sup 201}Tl mismatch, whereas only 8 (31%) of 26 patients in the nonsmoker group did (p=0.047). In conclusion, current smokers had more likelihood of salvageable myocardium in areas at risk, as demonstrated by BMIPP/{sup 201}Tl mismatch, in AMI than nonsmokers. (author)

Yamagishi, Hiroyuki; Akioka, Kaname; Shirai, Naoya; Yoshiyama, Minoru; Teragaki, Masakazu; Takeuchi, Kazuhide; Yoshikawa, Junichi; Ochi, Hironobu [Osaka City Univ. (Japan). Graduate School of Medicine

2001-09-01

4

Usefulness and limitation of stress 201Tl myocardial single photon emission computed tomography (SPECT) for diagnosis of ischemic heart disease  

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Stress 201-T1-myocardial single photon emission computed tomography (SPECT) proved to have significantly higher sensitivity than planar scintigraphy for the detection of ischemic heart disease (IHD), each affected artery, multi-vessel disease and three-vessel disease. It also permitted the detection of ventricular aneurysm. Diagnostic accuracy was influenced by the presence and severity of infarction, the number of affected vessels, and infarct site. Transient ischemia in the infarct site and ventricular aneurysm seemed to make it difficult to detect multi-vessel disease in cases of infarction. These resu lts indicated that SPECT is a noninvasive useful technique for detecting IHD, each affected artery, multi-vessel disease (especially, postero-inferior myocardial infarction), three-vessel disease, and ventricular aneurysm. However, SPECT seemed to have the limitation for detecting multi-vessel disease accompanied by anterior myocardial infarction and angina pectoris. (Namekawa, K.)

5

Evaluation of left ventricular function in patients with myocardial infarction by noninvasive techniques using two-dimensional echocardiography and 201Tl single photon emission computed tomography  

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Two dimensional echocardiography (2-DE) and 201Tl single photon emission computed tomography (SPECT) were performed in 51 patients with acute myocardial infarction (AMI), and the results were compared with those obtained by left ventriculography (LVG). After Loh et al.,the image of the left ventricular (LV) wall was divided into 9 segments. LV wall motion and Tl uptake in each segment were evaluated according to their severity and assigned scores from 1 to 5. The degree of global abnormality in each patient as determined by each method was obtained by the sum of the scores assigned to the 9 segments, and expressed as ?LVG, ?2-DE or ?SPECT, ?'LVG, ?'2-DE and ?'SPECT were also measured for 5 LV segments which were equivalent to the right anterior oblique view in LVG. Ejection fraction (EF) was measured by LVG using Kennedy's method. The mean value of ?2-DE was almost the same as that of ?LVG, but that of ?SPECT was significantly higher than that of ?LVG (p<0.05). The correlation coefficient of ?LVG with ?2-DE was 0.85 (p<0.001) and with ?SPECT, 0.72 (p<0.001). ?'LVG, ?'2-DE and ?'SPECT correlated significantly with EF (LVG: r=0.82; 2-DE: r=0.74; SPECT: r=0.63). Using multiple regession analysis, ?LVG and EF were estimated from the sum of the 2-DE and SPECT scores in each segment. In conclution, LV wall motion and ejection fraction can be estimated precisely by noninvasive diagnostic methods such as 2-DE and SPECT. (author)thor)

6

Practical assessment of myocardial viability with a positron coincidence gamma camera using 18F-fluorodeoxyglucose in acute myocardial infarction. Comparison with dedicated positron emission tomography and 201Tl single photon emission computed tomography  

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2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) began to be supplied commercially to our hospital, which does not have a cyclotron, in autumn of 2005. The purpose of this study was to compare the utility of a dual-head positron coincidence detection (PCD) gamma camera in the detection of myocardial viability using 18F-FDG with that of dedicated positron emission tomography (PET) and with that of thallium-201 (201Tl) single photon emission computed tomography (SPECT). A total of 15 patients (14 men and 1 woman, mean age: 60±7 years, range: 46-73) with a large acute myocardial infarction (AMI) underwent 18F-FDG PET, 18F-FDG PCD imaging after oral glucose loading (75 g) and 201Tl SPECT imaging. We divided the SPECT and PET images into a total of 20 segments, and semiquantitative visual analysis was performed by assessing regional tracer activities on a 4-point scoring system (DS): 0=normal uptake, 1=mildly reduced uptake, 2=severely reduced uptake, and 3=no uptake. We summed the DS in each patient as the total DS (TDS). The TDS of the 18F-FDG PET image was 14.4±7.7. The TDS of the 18F-FDG PCD image was 18.7±7.7. The TDS of the 201Tl SPECT image was 24.1±11.5. The TDS of the 18F-FDG PET image was significantly smaller than that of the 18F-FDG PCD image. The TDS of the 18F-FDG PET image was significantly smaller than that of the icantly smaller than that of the 201Tl SPECT image. The TDS of the 18F-FDG PCD image was significantly smaller than that of the 201Tl SPECT image. The findings of the project suggest that 18F-FDG PCD is a good modality based on its accuracy, convenience, and cost-performance for detecting myocardial viability in hospitals that do not have a PET system. (author)

7

Myocardial scintigraphy with 201Tl in angiosarcoma of the heart  

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The appearance of angiosarcoma of the heart in the myocardial image with 201Tl is described on hand of an casuistic example. This diagnostic procedure may be important for follow-up of therapeutic effects. (orig.)

8

Spontaneous changes in 201Tl myocardial perfusion imaging after myocardial infarction  

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To examine regional myocardial perfusion after myocardial infarction, 26 patients underwent exercise electrocardiographic testing with 201Tl myocardial perfusion imaging 3 weeks and 3 months after infarction. At 3 weeks, 9 of 26 patients (35%) had myocardial ischemia by exercise electrocardiographic testing, whereas 18 of 26 (69%) had ischemia by 201Tl imaging. The 201Tl scintigrams were scored by dividing each image, in 3 views, into 5 segments, using a 5-point scoring scheme. The exercise 201Tl score was 44.3 +/- 1.2 and increased to 47.3 +/- 1.2 in the redistribution study (p less than 0.001). Three months after infarction, although there was a significantly greater rate-pressure product which would predict a larger ischemic defect and a decrease in the stress 201Tl score, the stress score was improved (48.3 +/- 1.1, p less than 0.001). The redistribution score was similar, that is, 48.9 +/- 1.0. The improvement in 201Tl myocardial perfusion was associated with a loss of stress-induced ischemia in 8 patients (30%). These results indicate that spontaneous improvements in 201Tl myocardial perfusion imaging may occur after myocardial infarction

9

When is 201Tl myocardial scintigraphy indicated?  

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Myocardial scintigraphy with thallium-201 has met with good acceptance in cardiology and has proven its value. The method implies only low risk and yields diagnostic results that allow verification or disqualification of suspected myocardial ischemia in those cases where there is only reduced accuracy of the exercise electrocardiogram. (TRV)

10

Reverse 201Tl myocardial redistribution induced by coronary artery spasm  

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Objective: To investigate the mechanism of reverse redistribution (RR) on dipyridamole 201Tl myocardial perfusion studies in the patients with coronary artery spasm. Methods: Twenty-six patients with coronary artery spasm and presented as RR on dipyridamole 201Tl myocardial perfusion studies were enlisted as RR group, while other 16 patients with no coronary artery stenosis nor RR were enlisted as control group. Dipyridamole test was repeated during coronary angiography. Corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and TIMI myocardial perfusion grade (TMPG) were measured at RR related and non-RR related coronary arteries before and after dipyridamole infusion respectively. All of the data were analyzed by Student's t-test or ?2-test and correlation analysis. Results: Coronary artery angiography showed slower blood flow and lower myocardial perfusion in RR related vessels when compared with non-RR related vessels in RR group, but there was no significant difference among the main coronary arteries in control group. The perfusion defects of RR area at rest were positively related to slower blood velocity at corresponding coronary arteries (r = 0.79, t =10.18, P0.05). Conclusion: RR is related to the decreased blood flow and myocardial perfusion induced by coronary artery spasm at rest, which may be improved by stress test such as intravenous dipyridamole infusion. (authors)

11

123I-labelled BMIPP fatty acid myocardial scintigraphy in patients with hypertrophic cardiomyopathy: SPECT comparison with stress 201Tl  

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123I-labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) was performed in 17 patients with hypertrophic cardiomyopathy, and was compared with 201Tl exercise stress myocardial perfusion (SPECT) images. Fourteen patients showed asymmetrical hypertrophy, and three demonstrated apical hypertrophy. SPECT was performed 20 min and 3 h after injection of 111 MBq 123I-BMIPP at rest. Exercise stress 201Tl SPECT was performed at 10 min and 3 h after injection and was compared with BMIPP imaging. In 13 patients BMIPP accumulation in the hypertrophied area in the 20 min image was lower that that of 3 h 201Tl uptake. Interestingly, six patients demonstrated 201Tl redistribution in the region where the uncoupling of BMIPP uptake at 20 min and 201Tl accumulation at 3 h after exercise was observed. These findings suggest that impaired fatty acid metabolism or utilization in hypertrophic myocardium and ischaemia or impaired coronary flow reserve may be one of the causes of the abnormality of fatty acid accumulation. (Author)

12

201Tl in myocardial diagnosis: studies on the influence of dipyridamole, dobutamine ergometer exercise and background subtraction on the 201Tl myocadial scintiscam  

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Changes in 201Tl myocardial scintiscans upon administration of dipyridamole or dobutamine and upon ergometer exercise relative to scintiscans at rest were investigated as well as the influence of myocardial background subtraction on scintiscan quality and information. A total of 90 201Tl examinations were carried out in 59 patients. 18 patients had no myocardial disease, 30 patients had a coronary disease, 5 patients suffered from cardiomyopathy and 6 from left ventricular hypertrophy. The findings are discussed in detail. (orig.)

13

Sector analysis of myocardial 201Tl-redistribution  

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A method for quantitative 201Tl scintigraphy of myocardium is described. Myocardium is divided into 9 segments and examinated in terms of vitality and redistribution. Tl-washout is determined sectorally not globally as in previous programs. (orig.)

14

Myocardial 201Tl washout after combined dipyridamole submaximal exercise stress: Reference values from different patient groups  

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Dipyridamole stress is favorable in patients unable to exercise maximally for 201Tl myocardial scintigraphy. Aside from an analysis of uptake defects, proper washout analysis can be limited by heart rate variations when isolated dipyridamole stress is used. Heart rate standardized 201Tl washout kinetics after a combined dipyridamole and submaximal exercise stress protocol (CDSE), feasible in elderly patients as well as in patients with peripheral artery disease, were therefore studied to investigate the 201Tl washout after CDSE in differently defined patient groups: Group I comprised 19 patients with documented heart disease and angiographically excluded coronary artery disease (CAD); group II contained 17 patients with a very low likelihood of CAD determined by both normal exercise radionuclide ventriculography and normal 201Tl uptake. Group III comprised 56 patients with a 50% pretest likelihood of CAD but normal 201Tl uptake. Mean washout values were nearly identical in all groups. Despite similar uptake patterns, however, washout standardized by CDSE was significantly lower than the normal washout values after maximal treadmill exercise. Thus an obviously lower 201Tl washout after CDSE than after maximal treadmill exercise must be considered if washout analysis criteria after dipyridamole are applied to evaluate ischemic heart disease. Nevertheless, heart rate elevation achieved by additional submaxte elevation achieved by additional submaximal exercise stress seems necessary, adequate and clinically safe for standardisation of washout analysis in dipyridamole 201Tl scintigraphy. (orig.)

15

Dipyridamole 201Tl myocardial SPECT imaging in patients with dilated cardiomyopathy  

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Objective: To explore the characteristics of dipyridamole 201Tl myocardial perfusion imaging (MPI) SPECT in patients with dilated cardiomyopathy. Methods: Thirty patients with dilated cardiomyopathy underwent pharmacological stress 201Tl MPI SPECT after intravenous infusion of dipyridamole (0.56 mg/kg) for 4 min. The early and delayed SPECT images were acquired respectively at 10 and 240 min after 201Tl injection. The images were analyzed and reported by two or three experienced nuclear medicine physicians. Results: All patients were found to have abnormal perfusion patterns at delay imaging, however 90.00% (27/30) were also abnormal at early images. Six patients had reverse redistribution. Conclusion: Dipyridamole 201Tl MPI SPECT imaging may be of some value for the assessment of patients with dilated cardiomyopathy. (authors)

16

Considerations of 201Tl as a myocardial radionuclide imaging agent in man  

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Recent reports have suggested the use of intravenous 201Tl (thallium-201) for myocardial imaging with the gamma scintillation camera. In order to better appreciate the possible utility of this agent in humans we examined its distribution and kinetics in 13 patients and in six mongrel dogs, three with experimental coronary artery occlusion. In addition, 201Tl was compared to 86Rb (rubidium-86) in 84 rats. In the rat heart, the concentration of 201Tl was 30 percent higher than that of 86Rb ten minutes after injection. Moreover, myocardium-to-blood ratios for 201Tl averaged 51:1, but only 32:1 for 86Rb ten minutes after administration. In the dog heart, the distribution of 201Tl paralleled that of radioiodinated (131I) albumin particles injected into the left atrium and, thus, appears to be related to regional blood flow. Its concentration in ischemic regions decreased to 32.3 percent of the normally perfused myocardium. In the patients with a recent or old myocardial infarction, areas of decreased 201Tl uptake were easily identified and corresponded in location to that by ECG. Repeat scans 24 hours after the initial injection showed a significant retention of 201Tl by the myocardium. 201Tl blood levels in humans 15 minutes after injection were low (averaging 1.06 percent +- 0.41 percent SD of the total dose per liter) and these levels decretal dose per liter) and these levels decreased with a biological half-life of 3.1 +- 0.7 days. Twenty-four hour urinary excretion rates ranged from 0.6 to 6.5 percent of the total dose and appeared related to urinary flow and the concentration of 201Tl in blood. Because of the higher target to background ratios, 201Tl compares favorably with radioactive rubidium. 201Tl in diagnostic doses remained without detectable adverse effects and appears promising as an agent for visualizing abnormal regional myocardial perfusion in patients with coronary artery disease

17

Assessment of hibernating myocardium following coronary artery bypass grafting using resting 201Tl myocardial SPECT  

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In this study, the effect of coronary artery bypass grafting (CABG) in 35 patients (pts) (male 29, female 6) with fixed defects were evaluated before and one month after surgery using resting 201Tl SPECT. Nine pts (7 old myocardial infarction; OMI) had 2 vessel disease (VD) and 26 pts (19 OMI) had 3 VD. Pts ages ranged from 41 to 75 (mean 61.4±8.4) years. All 35 pts were divided into 4 groups according to the results of 201Tl SPECT and left ventriculogram pre- and post-CABG. Thirteen pts who improved of both 201Tl SPECT and wall motion scores post-CABG were considered as hibernating myocardium (group I). Nine patients who improved of 201Tl SPECT score but no change of wall motion were group II. Seven pts who improved of wall motion but no change of 201Tl SPECT score were group III. Six pts who had no improvement of both 201Tl SPECT and wall motion scores were group IV and considered as myocardial infarction. (author)

18

Impact of diabetes mellitus on worsening of the left ventricular ejection fraction in exercise-gated 201Tl myocardial single photon emission computed tomography in patients with coronary artery disease  

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It remains uncertain whether factors other than the severity of coronary artery disease (CAD) are associated with the worsening of the left ventricular ejection fraction (LVEF) by exercise. In the present study the impact of coronary risk factors on the worsening of LVEF by exercise was investigated in 391 patients with known or suspected CAD using exercise-gated 201Tl scanning to calculate the LVEF. Significant worsening of the LVEF by exercise was defined as >4.7% (mean plus 1 SD of the value in 116 patients without CAD). Multivariate analysis revealed that diabetes mellitus (DM) was an independent risk factor for the worsening of LVEF by exercise in patients with multivessel (2- or 3-vessel) CAD with an odds ratio (95% confidence interval) of 2.2 (1.1-4.5, p=0.037). In 157 patients with 2- or 3-vessel CAD, 20 (23.5%) of 85 nondiabetic patients and 31 (43.1%, p=0.009 vs nondiabetic patients) of 72 diabetic patients showed significant worsening of LVEF by exercise. In patients with 2- or 3-vessel CAD, there was no significant difference in Gensini score or reversibility of perfusion defects between nondiabetic and diabetic patients. Thus, DM is a risk factor for worsening LVEF by exercise in addition to the severity of CAD. (author)

19

Effects of ischemic-like insult on myocardial 201Tl accumulation  

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Despite extensive clinical use of thallium-201 (201Tl) for myocardial imaging, the effect of ischemia on myocardial accumulation and release of 201Tl independent of flow has not been fully defined. Therefore, myocardial accumulation of 201Tl in response to ischemic-like myocardial injury was assessed in vitro using the cultured fetal mouse heart preparation. Cultured fetal mouse hearts (n . 311) were subjected to injury simulating ischemia by deprivation of oxygen and oxidizable substrates for periods ranging from 15 minutes to 10 hours. The extent of irreversible injury was determined by the percentage of lactic dehydrogenase (LDH) lost from the hearts to the culture medium during recovery from injury. Injury was essentially reversible at 1 hour of insult. The fraction of 201Tl content in injured compared with control hearts was not significantly lower after 1 hour of insult. By 3 hours of insult, irreversible injury as assessed by loss of LDH was detectable and the extent of injury increased progressively through 10 hours. During the 3-10-hour period of irreversible injury, 201Tl accumulation within injured hearts compared with controls was related in a monotonically decreasing fashion to the loss of LDH as described by a mathematical kinetic model that fit the observations closely (R2 greater than 0.99). These results indicate that in this organ culture preparation, in which there is effectively an unlimited rewhich there is effectively an unlimited reservoir of 201Tl and no confounding effects of perfusion, the time-dependent 201Tl accumulation is determined by the extent of irreversible injury

20

Single photon tomography imaging of a standard heart phantom with 201Tl: A gamma camera based system  

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A standard heart phantom (University of lowa design), inlcuding discrete myocardial walls, a central blood pool, and a 24-cc transmural cold defect, was studied with both planar and transverse tomographic imaging. The heart phantom was filled with 201Tl and placed within a cylindrical tank containing water and 201Tl to simulae nonmyocardial background activity from the thorax. The tomographic imaging system used was a commercially available, rotating, large field-of-view gamma camera. Image reconstruction from 64 sampling angles was performed in a nuclear medicine minicomputer system. The percentage activity in the region of the defect (actual activity of 0) contrasted to the normal wall was compared between planar and 1.25-cm transaxial tomographic slices. Defect activity fell to between 65% and 85% of that of the opposing normal wall in planar images, whereas it fell to between 26% and 49% of that of the normal wall in the tomographic images. In most cases, tomographic defect activity was half or less than that in the planar image. The geographic extent of the defect was seen in an appropriate number of tomographic slices: i.e., the geographic 3.2-cm defect length was predominantly seen in three 1.25-cm transverse slices. We conclude that camera-based tomographic systems show promise for improved 201Tl myocardial defect detection and quantitation over conventional planar images. (orig.)

 
 
 
 
21

Inability of seven-pinhole myocardial tomography to obtain accurate 201Tl kinetic data  

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Seven-pinhole myocardial tomography has been reported to enhance the accuracy of thallium-201 (201Tl) studies in detecting patients with coronary artery disease. To determine if this approach can accuratley assess regional 201Tl kinetics, 12 dogs with temporary occlusion (mean 15 min) of either the left anterior descending (LAD) (n=6) or left circumflex (LCX) (n=6) coronary artery were studied. Thallium-201 was injected and serial 7-pinhole images were acquired during occlusion and following reflow (mean duration 175 min). Time-activity analysis was obtained from normal and ischemic regions of interest in the central pinhole image and the reconstructed tomographic images (TOMO-ROI). Time-activity data from corresponding normal and ischemic regions were also obtained using a circumferential graph program (TOMO-MAX). In addition, regional myocardial 201Tl activity was recorded continuously with a cadmium telluride radition probe sutured directly to the posterior myocardial wall. (orig./AJ)

22

Diagnosis of myocardial ischaemia using exercise ST mapping and afterload 201Tl scintigraphy  

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Two non-invasive methods are compared used in the diagnosis of myocardial ischaemia, i.e. precordial exercise mapping of the ST segment and after load 201Tl scintigraphy of the myocardium.High sensitivity of mapping (89.3%) and of 201Tl scan (92.9%) was found compared to the findings on the coronary arteries. The specificity of both methods was lower (57.1%). Both methods give similar results in diagnosis of myocardial ischaemia; for localization the affection site thallium scintigraphy of the myocardium is preferably used. (author). 2 figs., 2 tabs., 23 refs

23

Correlation between intracoronary 201Tl myocardial scanning, coronary angiography and left ventriculography  

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One hundred and six patients with angina pectoris who underwent routine coronary angiography and left ventriculography were given intracoronary injection of thallium-201. The myocardial images had excellent resolution because of lack of interference from the background activity. The myocardial images and the left ventriculograms showed 94 percent correlation. Correlation between scans and EKG was lower. There was no correlation between the degree of coronary artery stenosis and 201Tl scan. Currently, the intracoronary injection of 201Tl at rest does not yield additional information to coronary angiography and left ventriculography

24

Cold pressor 201Tl myocardial scintigraphy in the diagnosis of coronary artery disease  

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201Tl myocardial scintigraphy was performed during cold pressor stimulation in 36 patients aged 36 to 69 years. Thirty-one patients had coronary artery disease and 5 patients did not, as confirmed by coronary cineangiography. 201Tl (1.5 to 2 mCi) was injected at 30 seconds of the cold pressor stimulation. The product of systolic pressure X heart rate increased from a baseline of 77.4 +/- 16 (standard deviation [SD]) to 103.6 +/- 17 at 30 seconds of the cold pressor test (p less than 0.0005). Transient perfusion deficits developed in 24 of 31 patients with coronary artery disease (sensitivity 77%), and all 5 patients without coronary artery disease had normal scintigrams. The sensitivity in detecting coronary artery disease was 40% in patients with 1 vessel disease, 91% in patients with 2 vessel disease, and 100% in patients with 3 vessel disease. Exercise electrocardiograms (available in 29 of 36 patients) were positive for ischemia in 18 of 24 patients with coronary artery disease and in 1 of 5 patients without coronary artery disease (sensitivity 75% and specificity less than 80%). Exercise 201Tl scintigrams, obtained in 16 patients, were positive in 11 patients with coronary artery disease and positive cold pressor 201Tl scintigrams. Five patients without coronary artery disease and with normal cold pressor 201Tl scintigrams had normal exercise 201Tl scintigrams. Coronary cineangiography performed duams. Coronary cineangiography performed during cold pressor stimulation in 6 patients who had positive cold pressor and exercise 201Tl scintigrams did not show coronary spasm. Our data indicate that cold pressor thallium-201 scintigraphy offers promise as a noninvasive test in the diagnosis of coronary artery disease and may be used in patients in whom exercise testing is not feasible

25

Myocardial imaging in dogs treated with grisorixin: relationship between 201Tl uptake and coronary blood flow  

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201Tl myocardial imaging was performed in dogs after pretreatment with grisorixin, which appeared to increase the myocardial uptake of 201Tl. This effect of grisorixin was found to be dose dependent, with an optimal dose of 60 microgram/kg. The myocardial-to-background ratio, which was 1.92 in the control dogs, rose to 4.45. The increase in the absolute myocardial uptake was demonstrated in guinea pigs that received 201Tl after similar pretreatment with grisorixin. In the animals treated with 500 microgram/kg, the uptake of 201Tl by the heart was 35% over the control value. With 60 microgram/kg grisorixin, the coronary blood flow increased from 40 to 176 ml/min 5 min after the injection. This dose, optimal for imaging, induced the maximum vasodilator effect with only a very slight concomitant increase in the left-ventricular pressure and myocardial contractility. Above 60 microgram/kg, grisorixin appeared to be a potent inotropic agent, whereas below this dose it showed only coronary vasodilator properties. Some evidence for an ionophore effect of this compound was found in dogs pretreated with 60 microgram/kg. In these the radionuclide was injected when the coronary vasodilatation had become insignificant, but a significant improvement of the M/B ratio was still evident

26

Quantification of myocardial ischemia and infarction with single photon emission computed tomography  

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To evaluate the feasibility of 201Tl single photon emission computed tomography (SPECT) for quantitative detection of myocardial infarction and ischemia, scintigraphic studies were related to angiographic findings. In study A infarct sizes with SPECT were compared with the angiographic infarct sizes of 30 patients. A linear correlation was found for the % infarct of the left ventricular circumference between both methods (r=0.73; p 201Tl SPECT was used for quantification of myocardial ischemia. Forty-three patients underwent both stress 201Tl SPECT and biplane exercise left ventriculography. Ischemia was expressed as % defect size of the left ventricular circumference. Sensitivity and specificity for detection of ischemia were 96% and 100% respectively with stress SPECT. Extent of myocardial ischemia correlated significantly with both methods (r=0.63; SPECT defect=1.0 angiographic ischemia +2%; P 201Tl SPECT for diagnosis of coronary heart disease. (orig.)

27

Quantitative evaluation of coronary artery disease by 201Tl myocardial emission computed tomography  

International Nuclear Information System (INIS)

The purpose of this study is to investigate the value of quantitative evaluation by circumferential profile analysis of stress-redistribution myocardial 201Tl distribution and myocardial 201Tl washout to diagnose coronary artery disease in comparison with qualitative evaluation by visual segmental analysis, using emission computed tomography (ECT). In 14 normal cases and 57 cases with angiographically defined coronary artery disease, stress and redistribution ECT were performed. ECT data were acquired in a 64 x 64 matrix format from 90 projections over 360 degrees using an ECT system with dual opposed large-field gamma cameras. A total acquisition time was 6 minutes. Tomographic sections oriented perpendicular and parallel to the long axis of left ventricule were reconstructed. For qualitative evaluation, ECT myocardial images were divided into 8 segments and segmental analysis was made by visual interpretation. For quantitative evaluation, circumferential profile curves for stress-redistribution myocardial 201Tl distribution and myocardial 201Tl washout were generated and evaluated by comparing with normal limits, which were obtained from 14 normal cases. Quantitative evaluation showed superior diagnostic accuracies to qualitative evaluation in left anterior descending artery (from 82 % to 89 %), right coronary artery (from 79 % to 86 %) and left circumflex artery (from 79 % to 87 %) lesions. Moreover, the number of disease) lesions. Moreover, the number of diseased coronary arteries was more accurately predicted by quantitative evaluation. Especially in patients with three-vessel disease, 80 % of the patients was detected accurately by the quantitative evaluation, while only 30 % by the qualitative evaluation. We conclude that this quantitative evaluation for 201Tl myocardial ECT produces a remarkable improvement for predicting individual coronary artery disease and number of diseased coronary arteries. (author)

28

Reverse redistribution of thallium-201 myocardial single photon emission tomography and contractile reserve  

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The present study investigated the contractile reserve of myocardium exhibiting reverse redistribution (RRD) of thallium-201 (201Tl) after acute myocardial infarction. Forty patients experiencing their first acute myocardial infarction underwent resting 201Tl single-photon emission computed tomography (SPECT) and low-dose (5-10 ?g·kg-1·min-1) dobutamine stress echocardiography (DSE) within 4 weeks after the onset of infarction. The left ventricle was divided into 13 segments for analysis. The severity of defects in 201Tl SPECT and the extent of wall motion abnormality in DSE were visually assessed and scored. The sum of each defect score and wall motion score of infarct-related segments were defined as total defect score (TDS) and total wall motion score (TWM), respectively. Quantitative analysis of 201Tl uptake was also performed. Resting 201Tl SPECT revealed RRD in 16 patients (group RRD), fixed defect (FIX) in 23 patients (group FIX), and redistribution in one. There was a significant difference in improvement of TWM between rest and stress in TWM in both the RRD and FIX groups (p201Tl SPECT inting RRD on 201Tl SPECT in patients with acute myocardial infarction has greater contractile reserve than that exhibiting a fixed defect. (author)

29

99mTc-Isonitrile ('MIBI'): Chances to improve myocardial scintigraphy or substitute for 201Tl?  

International Nuclear Information System (INIS)

99mTc-MIBI has used to examine 22 patients for a qualitative and quantitative comparison to 201Tl myocardial scintigraphy and 99mTc-Erythrocytes- radionuclide ventriculography (=RNV) in patients with previous anterior (AWMI) and posterior wall myocardial infarction (PWMI). 1) Planar gated amplitude scintigrams (GAMS, MIBI) and planar amplitudes (RNV, Ery) correlated in AWMI (r=0.87), to minor degree in PWMI (r=0.76) pointing to a superiority of GAMS in PWMI. 2) Correlation of global EF (99mTc-MIBI vs. 99mTc-Ery) was good (r=0.75). 3) Perfusion and function are derivable by 99mTc-MIBI in a one-step procedure ('radionuclide myocardial ventriculography = RMV'). Thus MIBI may be suited to replace 201Tl and 99mTc-erythrocytes. However extensive clinical studies have to be carried out - similar to those available now for 201Tl - before the recommendation to replace 201Tl by MIBI would be justified. (orig.)

30

Multi-center study for the evaluation of clinical usefulness of attenuation and scatter correction on {sup 201}Tl myocardial SPECT  

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The aim of this study was to evaluate the clinical usefulness of attenuation and scatter correction (AC, SC) on a {sup 201}Tl myocardial single-photon emission computed tomography ({sup 201}Tl SPECT) as a multi-center trial. With a dual-detecter and a triple-detector SPECT systems with a {sup 99m}Tc transmission source, simultaneous transmission/emission tomography (TCT/ECT) was performed on 38 patients with angiographically coronary heart disease (CHD) and 26 patients without evidence of CHD. Stress and delayed attenuation and scatter corrected images (SAC) and uncorrected images (NC) were reconstructed. On NC images of normal cases, influence of attenuation was greater in male than female. In comparison of {sup 201}Tl distribution between male and female, significant decrease in {sup 201}Tl activity was observed in the inferoposterior wall in male and that was observed in the anterobasal wall of the left myocardium in female. Such a difference in {sup 201}Tl distribution between male and female disappeared on SAC images. On the diagnostic performance for the identification of CHD, SAC images demonstrated improved specificity and accuracy values in the right coronary arterial territory (RCA) with visual analysis statistically. Sensitivity value in the RCA was also improved, but it was not statistically significant. Sensitivity value in the left circumflex arterial territory (LCX) increased without decrease in specificity value on SAC images. In the left anterior descending arterial territory (LAD), sensitivity value increased on SAC images. Although specificity value decreased on SAC images in LAD territory, it was not statistically significant. The difference in {sup 201}Tl distribution between male and female is improved in normal cases by attenuation and scatter correction on {sup 201}Tl myocardial SPECT. Diagnostic performance of CHD is also improved by attenuation and scatter correction, especially in territories of which specificity in assessing the absence of disease have been suboptimal. In conclusion, attenuation and scatter correction on {sup 201}Tl myocardial SPECT is considered to be clinically useful. (author)

Tomiguchi, Seiji [Kumamoto Univ. (Japan). Hospital; Kumita, Shin-ichiro [Nippon Medical School, Tokyo (Japan); Hashimoto, Jun [Keio Univ., Tokyo (Japan). School of Medicine; Inoue, Tomio [Gunma Univ., Maebashi (Japan). School of Medicine; Nomura, Yoshiyuki [Mie Univ., Tsu (Japan). School of Medicine; Emoto, Junichi [Handa Municipal Hospital, Aichi (Japan); Nakajima, Kenichi [Kanazawa Univ. (Japan). School of Medicine; Nishimura, Tunehiko [Kyoto Prefectural Univ. of Medicine (Japan)

2002-02-01

31

ATP-loading 201Tl myocardial SPECT for the detection of ischemic heart disease  

International Nuclear Information System (INIS)

To evaluate the usefulness for the detection of ischemic heart disease, ATP myocrdial SPECT was performed in 35 patients (mean; 59±9.4 years) with angina pectoris or old myocardial infarction. Coronary angiography (CAG) was performed in all patients. The ultra-short half-life of ATP required a continuous infusion for its use. ATP was infused intravenously at a rate of 0.16 mg/kg/min for 5 min, with 201Tl injection taking place at 3 min. Myocardial SPECT imaging was begun 5 min and 4 hr later after the end of ATP infusion. ATP caused a significant decrease in arterial blood pressure (p201Tl myocardial SPECT for the detection of coronary artery disease (CAD) was evaluated using CAG as a golden standard. The sensitivity and specificity for CAD detection were 82% and 90%, respectively. ATP myocardial SPECT is a promising new test for the detection of ischemic heart disease. (author)

32

Parameters for discriminating multiple-vessel coronary artery lesion in exercise 201Tl myocardial SPECT  

International Nuclear Information System (INIS)

This study was performed to select parameters most suitable for discriminating multiple-vessel lesion in exercise 201Tl SPECT. Exercise 201Tl SPECT and coronary contrasting were carried out in 110 patients. At 1 min before the end (appearance of heart pain, severe arrhythmia, hypotension or fatigue) of exercise with a bicycle ergometer, 4 mCi of 201Tl was intravenously injected and myocardial SPECT was done with gamma camera from 32 directions for 20 sec at 5 min and 4 hr after the exercise. Images were analyzed by scaring the uptake of 201Tl for left ventricle. Parameters were Initial score of Tl uptake, Score difference of Tl uptake, Lung/heart, Initial width, Width difference, Diffuse slow washout, Cavity/myocardium, Lung/myocardium and Lung/cavity. Parameters versus Number of diseased vessels were analyzed by chi square method or ANOVA and the parameters for the present purpose were selected by stepwise discriminant analysis. Lung/heart and Initial score were found most suitable. (K.H.)

33

Parameters for discriminating multiple-vessel coronary artery lesion in exercise {sup 201}Tl myocardial SPECT  

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This study was performed to select parameters most suitable for discriminating multiple-vessel lesion in exercise {sup 201}Tl SPECT. Exercise {sup 201}Tl SPECT and coronary contrasting were carried out in 110 patients. At 1 min before the end (appearance of heart pain, severe arrhythmia, hypotension or fatigue) of exercise with a bicycle ergometer, 4 mCi of {sup 201}Tl was intravenously injected and myocardial SPECT was done with gamma camera from 32 directions for 20 sec at 5 min and 4 hr after the exercise. Images were analyzed by scaring the uptake of {sup 201}Tl for left ventricle. Parameters were Initial score of Tl uptake, Score difference of Tl uptake, Lung/heart, Initial width, Width difference, Diffuse slow washout, Cavity/myocardium, Lung/myocardium and Lung/cavity. Parameters versus Number of diseased vessels were analyzed by chi square method or ANOVA and the parameters for the present purpose were selected by stepwise discriminant analysis. Lung/heart and Initial score were found most suitable. (K.H.)

Kurata, Chihiro; Wakabayashi, Yasushi; Okayama, Kenichi; Shoda, Sakae; Yamazaki, Noboru [Hamamatsu Univ., Shizuoka (Japan). School of Medicine; Tawarahara, Kei

1996-10-01

34

Prognostic investigations after myocardial infarction: A comparison of radionuclide angiography and 201Tl scintigraphy  

International Nuclear Information System (INIS)

The ability of pre-discharge thallium Tl201 scintigraphy and radionuclide angiography (RNA) to predict subsequent cardiac events was investigated in 46 apparently low-risk survivors of a first acute myocardial infarction. All patients underwent selective coronary arteriography at 3 months post-discharge. At the time of the initial investigation, half were beta-blocked, and thereafter, all patients were given prophylactic beta-blockade. During a mean follow-up period of 12+-4 months, 14 patients (30%) experienced cardiac events, i.e. recurrent myocardial infarction (3 patients), angina pectoris (13 patients) and coronary surgery (8 patients). No patient died during the follow-up period. Of the 14 with subsequent cardiac events, 11 were identified by the presence of a reversible perfusion defect at 201Tl scintigraphy, while 7 exhibited abnormal left ventricular exercise reserve on RNA. The predictive accuracy of 201Tl (85%) for subsequent cardiac events exceeded that of RNA (56%; P201Tl scintigraphy appears to be the more accurate technique for the assessment of the prognosis of apparently low-risk patients following myocardial infarction. The accuracy of the technique was not reduced by beta-adrenergic blockade. (orig.)rig.)

35

Thrombolysis in acute myocardial infarction using intracoronary streptokinase: assessment by 201Tl scintigraphy  

International Nuclear Information System (INIS)

Twenty-one patients with acute myocardial infarction, admitted to the hospital within 4 hours after the onset of symptoms, were studied by seven-pinhole 201Tl scintigraphy before and 1 hour and 24 hours after intracoronary fibrinolysis using streptokinase. The size of the 201Tl perfusion defect was assessed from myocardial cross sections reconstructed from the original seven-pinhole data and expressed as a fraction of left ventricular circumference. Recanalization was achieved in 16 patients within 3.9 +/- 1.6 hours after onset of symptoms (group A). In these patients, the size of the perfusion defect had decreased from 36 +/- 17% to 19% +/- 15% (p less than 0.001) at 24 hours. No significant change was detected by redistribution at 1 hour after the intervention. In five patients, intracoronary fibrinolysis was unsuccessful, and the vessel remained occluded (group B). The 201Tl perfusion defect affected 40 +/- 15% of the left ventricular circumference before the intervention; it remained virtually unchanged at 1 hour (37 +/- 16%) and at 24 hours (41 +/- 15%) after fibrinolysis. The perfusion defect was most reduced in patients with extensive collaterals supplying the ischemic area or with subtotal occlusion of the affected coronary artery. We conclude that successful intracoronary fibrinolysis may reduce the size of the 201Tl perfusion defect in many patients with acute myocardial infarction. One important factor in the finafarction. One important factor in the final result may be the presence of residual coronary flow supplied by extensive collaterals or by subtotal occlusion of the affected coronary artery when reperfusion is achieved around 4 hours after the onset of symptoms

36

Graft patency and myocardial viability after aorto-coronary bypass surgery evaluated by exercise /sup 201/Tl myocardial SPECT  

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To evaluate graft patency and myocardial viability after aorto-coronary (AC) bypass surgery, 58 patients (29 with old myocardial infarction and 29 with effort angina) underwent symptom-limited exercise /sup 201/Tl myocardial SPECT using a bicycle ergometer before and after surgery. The results were as follows: 1. The overall angiographic graft patency was 87% (97 of 112 grafts). 2. According to the stress SPECT images, graft patencies were 98% for areas with postoperative improvement by /sup 201/Tl uptakes, 79% for areas with unchanged patterns, and 53% for areas with worsened patterns. In spite of patent grafts, among cases with worsened /sup 201/Tl uptakes the etiologies included perioperative infarction, anastomotic strictures, and poor run-off distal to the anastomoses. 3. Following patency of grafts, postoperative normalized perfusion patterns were observed in 69% (27 of 39 segments) of segments with persistent preoperative low uptakes and 25% (4 of 16 segments) of segments with persistent preoperative defects. Thus, exercise /sup 201/Tl myocardial SPECT proved a useful diagnostic means of assessing graft patency and effectiveness. However, after AC bypass surgery, 25% of the regions which had persistent defects before surgery exhibited normal perfusion patterns. These findings suggest that persistent defects may represent hypoperfusion of viable myocardium, and that we should carefully diagnose myocardial scars.

Yada, Takashi; Futagami, Yasuo; Koyama, Takao and others

1988-06-01

37

Evaluation of myocardial viability following acute myocardial infarction using 201Tl SPECT after thallium-glucose-insulin infusion. Comparison with 18F-FDG positron emission tomography  

International Nuclear Information System (INIS)

The aim of this study was to evaluate myocardial viability in patients after acute myocardial infarction (AMI). We compared 201Tl SPECT after 201Tl with GIK (10% glucose 250 ml, insulin 5 U and KCI 10 mEq) infusion (GIK-201Tl) with resting 201Tl and 99mTc-pyrophosphate (PYP) dual SPECT, positron emission computed tomography (PET) using 18F-fluorodeoxyglucose (18F-FDG) in 21 patients with their first AMI, who all underwent successful reperfusion. GIK-201Tl SPECT, 201Tl and 99mTc-PYP dual SPECT were done within 10 days after admission and 18F-FDG-PET was performed at 3 weeks. GIK-201Tl SPECT was obtained after 30 min of GIK-201Tl infusion. 18F-FDG (370 MBq) was injected intravenously after oral glucose (1 g/kg) loading, and then PET was obtained. PET and SPECT images were divided into 20 segments. Regional tracer uptake was scored using a 4-point scoring system (3=normal to 0=defect), and summed to a regional uptake score (RUS). Regional area means the infarcted area in which 99mTc-PYP accumulated. The number of decreased uptake segments (ES) was then determined. The infarcted area was defined as the area of 99mTc-PYP uptake. The ESs for the GIK-201Tl and 18F-FDG-PET images were significantly lower than the number of 99mTc-PYP uptake segments. The RUS for GIK-PYP uptake segments. The RUS for GIK-201Tl was higher than that for resting-201Tl imaging and similar to those for 18F-FDG-PET. In the detection of myocardial viability following AMI, GIK-201Tl imaging is useful with findings similar to those of 18F-FDG-PET. (author)

38

Normal 201Tl SPECT myocardial scintigram - a basis for quantification of tomographic data using 1800 rotation  

International Nuclear Information System (INIS)

Using 1800 rotation for 201Tl myocardial perfusion SPECT the influence of different myocardial wall thickness, depth-dependent resolution, attenuation and other facts is the reason for about 30% inhomogenity from anterolateral to posteroseptal myocardium in polar coordinate Bull's eye. It is very difficult for a visual observer to assess patients without knowledge of the corresponding normal distribution. We studied 25 normal males and calculated pixelwice vitality, washout rate between stress, 2-hr and 3.5-hr delay to obtain a normal Bull's eye reference databank. Before the patient's data can be analysed it is necessary to multiplicate them with the inverse normal Bull's eye. (author)

39

Evaluation of viability of infarcted myocardium by low dose dobutamine stress echocardiography. Comparison with exercise stress 201Tl myocardial scintigraphy  

International Nuclear Information System (INIS)

Exercise stress 201Tl myocardial single-photon emission computed tomography (SPECT) is recognized to be a excellent method for identifying viability after myocardial infarction, but it is expensive and needs a longer time for data acquisition than echocardiography. We therefore performed this study to evaluate the effectiveness of low dose (5-10 ?g/kg/min) dobutamine stress echocardiography (DSE) in 30 patients (61±8 years old: 24 men and 6 women) within 4 weeks after myocardial infarction in identifying viable myocardium, compared to results obtained by SPECT. Defining an akinetic or dyskinetic segment obtained by rest echocardiography as a definite infarct area, altogether 96 segments out of 716 segments were shown to be infarct areas. Of these, 75 (78%) segments were identified as viable by DSE, and 77 (80%) by SPECT. Only 2 segments were shown to be discrepant on DSE and SPECT. Subsequently, the sensitivity, specificity and accuracy rates for DSE were 96%, 100% and 96%, respectively. In conclusion, DSE is as effective and useful as SPECT in the evaluation of viability after myocardial infarction. (author)

40

201Tl myocardial imaging in patients with pulmonary hypertension  

International Nuclear Information System (INIS)

The appearance of the right ventricular myocardium on thallium 201 myocardial perfusion images was evaluated in patients with chronic pulmonary hypertension and compared to patients without pulmonary hypertension. Four groups of patients were studied: (1) eight normals, (2) five patients with angiographically documented coronary artery disease and normal pulmonary artery pressures, (3) ten patients with moderate to severe pulmonary parenchymal or vascular disease and documented pulmonary hypertension and (4) eight patients with chronic left ventricular dysfunction and pulmonary hypertension discovered during cardiac catheterization. The right ventricular free wall was visualized on the thallium 201 myocardial perfusion image in only one of eight normals (group 1) and in only one of the five patients with coronary artery disease (group 2) and measured 0.5 cm and 0.9 cm in thickness, respectively. In patients with documented pulmonary hypertension the right ventricle was visualized on low contrast thallium 201 myocardial perfusion image in all patients. The apparent right ventricular free wall thickness measured from the ungated thallium 201 myocardial perfusion images was 1.7 +- 0.3 cm in group 3 and 1.5 +- 0.2 cm in group 4. Right ventricular hypertrophy was detected by electrocardiography in only five of ten patients in group 3 and only one of eight patients in group 4. Thallium 201 myocardial perfusion imaging appears to be a useful technique for assessing the effeca useful technique for assessing the effects of chronic pulmonary hypertension on the right ventricular myocardium

 
 
 
 
41

Experimental regional myocardial ischaemia and myocardial uptake of potassium analogues; intercomparison of 42K, 86Rb and 201Tl  

International Nuclear Information System (INIS)

The uptake of 42K, 86Rb and 201Tl by non-ischaemic and ischaemic myocardium was determined in rats with coronary artery ligature lasting 10, 30, 60 and 120 min, and in control rats without ischaemia. Whereas the myocardial concentration of 201Tl and 42K in control rats was similar and higher than that of 86Rb, 201Tl was superior to the other two radionuclides due to its significantly higher accumulation in non-ischaemic myocardium and the higher ratio of non-ischaemic to ischaemic radioactivity. The 86Rb accumulation in non-ischaemic myocardium and non-ischaemic/ischaemic ratio began to decrease from its maximum at 10 min. 201Tl, 42K and 86Rb blood levels in intact animals decreased rapidly after intravenous injection to low and nearly stabilized values at 5 min. Na+K+-ATPase activity in the ischaemic myocardium was high in the acutely ischaemic myocardium and decreased to below control levels after 4 h of ischaemia; changes in activity could not influence the low uptake of potassium analogues in fresh ischaemic myocardium. (orig.)

42

Myocardial scintigraphic studies with 123I-MIBG, 201Tl and 99mTc-PYP in patients with cardiac amyloidosis  

International Nuclear Information System (INIS)

Myocardial scintigraphic studies, using 123I-metaiodobenzylguanidine (MIBG), 99mTc-pyrophosphate (PYP) and 201Tl were performed in 4 patients with cardiac amyloidosis. In MIBG myocardial images, 2 patients with familial amyloid polyneuropathy (FAP) showed complete or partial defect and the other 2 with primary amyloidosis had normal myocardial uptake of MIBG. In PYP myocardial images, diffuse myocardial uptake of PYP was mild in 2 patients with FAP and moderate in the other 2. 201Tl myocardial images revealed normal myocardial uptake of 201Tl in 2 patients with FAP and 1 with primary amyloidosis, and intense myocardial uptake in the other one with primary amyloidosis. These results suggest that myocardial scintigraphies with PYP and 201Tl may be useful for the detection of cardiac amyloidosis and estimation of its pathophysiology. And MIBG myocardial scintigraphy may provide useful information about sympathetic nerve abnormalities which vary with type of the fibril protein, clinical syndromes and disease process of cardiac amyloidosis. (author)

43

Influence of increased [sup 201]Tl lung uptake on the myocardial viability of the patients with dilated cardiomyopathy under congestive heart failure  

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Influence of increased [sup 201]Tl lung uptake on the myocardial viability was studied in 15 patients with dilated cardiomyopathy under congestive heart failure. Rest and 4 hours delayed [sup 201]Tl SPECT were obtained. At the same time anterior planar images were collected. In 10 patients of 15 patients [sup 201]Tl lung heart ratio in SPECT (LHR) was larger than that in planar images. Maximal [sup 201]Tl lung uptake was noted at the lower left lung adjacent to the heart. In the delayed images [sup 201]Tl lung uptake diminished. In 10 patients the value of LHR in the delayed images was less than 0.5. By comparing initial images with delayed images it was proved to be difficult to determine the myocardial margin adjacent to the increased [sup 201]Tl lung uptake. In 2 patients lateral defects were concealed by the increased [sup 201]Tl lung uptake. In the remaining patients lateral wall was similar to the hypertrophic myocardium. The effect of scatter due to the increased [sup 201]Tl lung uptake was noted in the neighboring myocardium. In most cases %[sup 201]Tl uptake in the septum was relatively depressed by increased %[sup 201]Tl uptake in the lateral wall. In the delayed images pseudo-redistribution was noted in the septum. Mean value of differences in %[sup 201]Tl uptake between initial and delayed images was 8(2-15)%. It was concluded that in case of increased [sup 201]Tl lung uptake SPECT could not accurately estimate myocardial viability by initial images and delayed images were necessary for precise estimation. (author).

Tanaka, Takeshi; Nakano, Hajime; Katoh, Kazuzo (Cardiovascular Inst., Tokyo (Japan))

1992-11-01

44

Evaluation of 3 dimensional space and time filtering on ECG gated 201Tl myocardial images  

International Nuclear Information System (INIS)

Stress 201Tl myocardial images were obtained using a standard ECG gated acquisition protocol for 10 min per view. These images were filtered using a three dimensional space time filter. The effects of filtering were evaluated by sectoral analysis. Comparing raw and filterd dynamic images, quantification demonstrated that filtering did not produce artefacts. A conventional static image was also obtained as the sum of the series of unfiltered dynamic images. Comparison of raw static and filtered diastolic images indicated that the latter demonstrated myocardial abnormalities more clearly (P<0.01) in 33 patients. Improvement in the signal to noise ratio produced by filtering made cinematic display and visual analysis possible which was not feasible with raw gated images. Clinical evaluation is in progress. (orig.)

45

Simultaneous 201Tl/99mTc seven-pinhole tomography in acute myocardial infarction  

International Nuclear Information System (INIS)

Combined infarction scintigraphy with 201Tl-chloride and 99mTc-pyrophosphate (PPi) by simultaneous seven-pinhole tomography was investigated with a phantom as well as in patients. No artificial defects occurred when the collimator was centered correctly in axial position, but a very high standard of image uniformity and linearity of the gamma camera was required. Artefacts by overlying activity from the skeleton or cardiac blood pool were not observed. All 11 controls showed normal results. Despite a poor depth resolution due to limitations of the system even small areas of partially damaged myocardium could be recognized and correlated three-dimensionally. Of 24 patients with proven myocardial infarction, in 16 both a positive (99mTc-PPi) and a negative (201Tl) image was obtained in congruence with the necrosis. 8 patients (33%) showed discordant results providing however additional information on the nature and extent of the necrosis. 4 out of 6 non-transmural infarctions seen by tomography had been suspected clinically. (orig.)

46

Myocardial imaging with 201Tl: an analysis of clinical usefulness based on Bayes' theorem  

International Nuclear Information System (INIS)

Rest-exercise thallium-201 (201Tl) myocardial imaging and rest-exercise electrocardiography were performed in 137 patients with suspected coronary artery disease (CAD). The final diagnosis of coronary disease was made by arteriography. Sensitivity and specificity for the ECG and thallium studies alone or combined were then determined. Based on these data, the posttest probability of CAD with a normal or abnormal test was calculated using Bayes' theorem for disease prevalences ranging from 1% to 99%. The difference between the probability of disease with a normal test and the probability of disease with an abnormal test was also calculated for each prevalence range. The results demonstrate that 201Tl imaging discriminates between disease absence or presence better than does the ECG. However, both the ECG and thallium studies provide rather poor discrimination between disease and no disease when the disease prevalence is low (less than 0.20) or high (greater than 0.70). Because of this characteristic, it is unlikely that screening tests for CAD will prove useful unless the disease prevalence in the group under study is in the moderate (0.20 to 0.70) range

47

Usefulness of 201TlCl/123I-BMIPP dual-myocardial SPECT for patients with non-ST segment elevation myocardial infarction  

International Nuclear Information System (INIS)

Earlier studies suggested that elevated cardiac troponin T (cTnT) might be useful for detecting less severe types of myocardial injury (i.e., non-ST segment elevation myocardial infarction). The objective of this study is to elucidate the usefulness of 201thallous chloride (201TlCl) and 123I-betamethyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) dual-single-photon emission computed tomography (SPECT) imaging for patients with myocardial infarction (MI) without ST segment elevation. Consecutive 86 patients (56 men and 30 women; mean age 66±12 years) clinically diagnosed with acute myocardial infarction (AMI) were divided into two groups according to serum creatine kinase MB (CK-MB) and cTnT levels. Group A consisted of 53 patients with increased serum CK-MB and cTnT levels, and Group B, 33 patients with increased serum cTnT without increased serum CK-MB. All patients underwent 201TlCl and 123I-BMIPP dual-SPECT about 8 days following the onset. The left ventricular myocardium was divided into 20 segments on each SPECT image, and tracer accumulation in those segments was scored on a five-point scoring system. The total defect scores (TDS) were calculated by summing the scores for all 20 segments, and compared between groups A and B. Group B patients were subdivided into two groups according to the TDS on 123I-BMIPP images as groups Bs (severe; TDS?8) and BM (ub> (severe; TDS?8) and BM (mild; TDS?7), and we compared the prognosis over a period of 2 years from the onset between the three groups. The TDS of group A derived from 201TlCl and 123I-BMIPP images was significantly higher than those of group B (14.5±10.8 vs. 1.5±2.4 and 20.8±13.3 vs. 9.1±6.2, respectively; P201TlCl and 123I-BMIPP images were 94.3% (50/53) and 96.2% (51/53) to detect the culprit coronary lesions in group A (no significant difference). In contrast, the sensitivity of 123I-BMIPP images (72.7%, 24/33) was higher than that of 201TlCl images (27.3%, 9/33) in group B (PS, and BM was 24.5%, 27.8%, and 6.7%, respectively. The rate of group BS, as well as that of group A, was significantly higher than that of group BM (P123I-BMIPP imaging is useful not only for the detection of the culprit lesions but also for the prediction of the prognosis. (author)

48

Reverse redistribution of thallium-201 myocardial single photon emission tomography and contractile reserve  

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The present study investigated the contractile reserve of myocardium exhibiting reverse redistribution (RRD) of thallium-201 ({sup 201}Tl) after acute myocardial infarction. Forty patients experiencing their first acute myocardial infarction underwent resting {sup 201}Tl single-photon emission computed tomography (SPECT) and low-dose (5-10 {mu}g{center_dot}kg{sup -1}{center_dot}min{sup -1}) dobutamine stress echocardiography (DSE) within 4 weeks after the onset of infarction. The left ventricle was divided into 13 segments for analysis. The severity of defects in {sup 201}Tl SPECT and the extent of wall motion abnormality in DSE were visually assessed and scored. The sum of each defect score and wall motion score of infarct-related segments were defined as total defect score (TDS) and total wall motion score (TWM), respectively. Quantitative analysis of {sup 201}Tl uptake was also performed. Resting {sup 201}Tl SPECT revealed RRD in 16 patients (group RRD), fixed defect (FIX) in 23 patients (group FIX), and redistribution in one. There was a significant difference in improvement of TWM between rest and stress in TWM in both the RRD and FIX groups (p<0.0001, each case). The improvement of TWM with dobutamine was significantly greater in RRD than in FIX (1.6{+-}1.0 vs 0.6{+-}0.7, p=0.001). There was a positive correlation between the magnitude of RRD and improvement of TWM with dobutamine (r=0.48, p=0.002). Myocardium exhibiting RRD on {sup 201}Tl SPECT in patients with acute myocardial infarction has greater contractile reserve than that exhibiting a fixed defect. (author)

Hirata, Kumiko; Yamagishi, Hiroyuki; Tani, Tomoko; Sakanoue, Yuji; Akioka, Kaname; Takeuchi, Kazuhide; Yoshikawa, Junichi; Ochi, Hironobu [Osaka City Univ. (Japan). Medical School

2000-05-01

49

Intravenous streptokinase therapy in acute myocardial infarction: Assessment of therapy effects by quantitative 201Tl myocardial imaging (including SPECT) and radionuclide ventriculography  

International Nuclear Information System (INIS)

To evaluate a potential beneficial effect of systemic streptokinase therapy in acute myocardial infarction, 36 patients treated with streptokinase intravenously were assessed by radionuclide ventriculography and quantitative 201Tl myocardial imaging (including SPECT) in comparison with 18 conventionally treated patients. Patients after thrombolysis had significantly higher EF, PFR, and PER as well as fewer wall motion abnormalities compared with controls. These differences were also observed in the subset of patients with anterior wall infarction (AMI), but not in patients with inferior wall infarction (IMI). Quantitative 201Tl imaging demonstrated significantly smaller percent myocardial defects and fewer pathological stress segments in patients with thrombolysis compared with controls. The same differences were also found in both AMI and IMI patients. Our data suggest a favorable effect of intravenous streptokinase on recovery of left ventricular function and myocardial salvage. Radionuclide ventriculography and quantitative 201Tl myocardial imaging seem to be reliable tools for objective assessment of therapy effects. (orig.)

50

Quantitative evaluation of serial 201Tl myocardial scintigrams after stress testing in ischemic heart disease  

International Nuclear Information System (INIS)

Five normal adults and 31 patients with ischemic heart disease were studied by stress test, and 201Tl was injected one min. before the end of the test. Myocardial scintigrams in three views were recorded at 10 min, 1 and 2 hours (phase 0, 1 and 2) after the injection. The myocardial wall was geometrically divided into 5 segments. At the area where the count rate (Cts) was highest in phase 0 scintigrams, the washout rate from phase i to j was defined as WRij = (maxCtsi - maxCtsj)/maxCtsi where Ctsi denoted Cts at phase i in the relevant area. The redistribution index (Rdsij) in each segment was defined as Rdsij = (Ctsi x WRij + (Ctsi - Ctsj))/Ctsi, where Ctsi denoted Cts at phase i in the segment. The ischemic segment was identified as 70% or less of maxCts 0, while the infarcted segment by VCG in phase 0 scintigram. Mean values of Rds 02 in the normal, ischemic and infarcted segments were -6.1 +- 5.6, 9.7 +- 7.0 and 3.5 +- 7.2%, respectively, and the differences were statistically significant (p WR01 after the stress was reliable in suggesting myocardial ischemia. (author)

51

Correlation between angiogenesis and reduction ratio measured using 201Tl chloride single photon emission computed tomography in patients with oral cavity squamous cell carcinoma  

International Nuclear Information System (INIS)

The aim of this study is to examine the correlation between tumor angiogenesis and response to preoperative radiotherapy evaluated using 201Tl single photon emission computed tomography (Tl SPECT) in oral cavity squamous cell carcinoma (SCC). Tl SPECTs before and after preoperative radiotherapy were obtained from 11 patients diagnosed with SCC in oral cavity. Regions of interest were set around the tumor and scalp respectively, and the ratio of mean counts in the tumor to those in the scalp was calculated (T/N). Immunohistochemical staining for investigating microvessel density of pre-treatment biopsy specimen was performed using CD31 monoclonal antibody. We compared microvessel density with semi-quantitative parameters obtained using Tl SPECT (T/N at pre- an post-treatment, reduction ratio) and prognosis. The subgroup with higher microvessel density showed a significantly higher reduction ratio than the one with lower microvessel density. Regarding prognosis, the subgroup with locoregional recurrent disease exhibited a significantly higher microvessel density than the one without recurrence. In SCC of the oral cavity, there was a significant correlation between microvessel density and response to preoperative radiotherapy. Namely, it was revealed that change of 201Tl uptake after preoperative radiotherapy correlated with tumor angiogenesis of oral cavity SCC. (author)

52

A clinical study of gated simultaneous rest 201Tl/stress 99Tcm-sestamibi dual isotope myocardial perfusion imaging  

International Nuclear Information System (INIS)

Objective: To investigate a modified gated radionuclide myocardial tomography in methodology for raising the sensitivity and efficiency of detecting myocardial ischemia. Methods: One hundred and three patients were involved and divided into two groups: coronary artery disease (CAD) patient 37, non-CAD patient 66. 201Tl 111 MBq was injected intravenously 5 min before stress, the patient exercised with ergometer following the modified Bruce protocol, and was injected 99Tcm-sestamibi at the peak of stress. 45 min later, the simultaneous dual energy peak gated acquisition was then performed. Stress (99Tcm-sestamibi) and rest (201Tl) images were reconstructed. Results: Positive findings were seen in 35/37 (94.6%) in CAD group and 7/66 (10.6%) in non-CAD, respectively; LVEF, EDV and ESV of two groups were (52.33+-16.26)%, (70.45+-28.12) mL, (33.35 +- 18.86) mL and (61.76 +- 9.38)%, (60.45 +- 18.18) mL, (23.30 +- 11.09) mL, respectively. Conclusion: The simultaneous stress (99Tcm-sestamibi) and rest (201Tl) gated myocardial imaging is an efficient and practical protocol for the study of myocardial perfusion and the diagnosis of ischemia

53

Measurement of myocardial uptake rate and method of dual energy data acquisition in myocardial scintigraphy with 123I-metaiodobenzylguanidine and 201Tl-chloride, 1  

International Nuclear Information System (INIS)

I proposed a simple method to compute the myocardial uptake rate (MUR) of tracers in myocardial scintigraphy using the myocardial and pulmonary attenuation coefficients with the planar images, assuming that the myocardial and pulmonary tissues had uniform attenuation. The MUR was attained by calculating the lateral length of the myocardium and the lung and two of three other parameters: the anterior or the posterior mean counts of the myocardium or the anterior mean counts of the lung. In the heart phantom study, the radioactivity of left ventricular wall calculated through this method agreed well with that of the RI calibrator. The method proved useful for evaluating myocardial uptake of tracers in myocardial scintigraphy. In the dual energy data acquisition of 123I or 201Tl, the crosstalk correction of each radioisotope provided the total myocardial uptake rate attained by calculating the total counts of myocardium of the planar images although the effects of the 123I scatter on the 201Tl energy images were greater than those of 201Tl on the 123I energy images. I concluded that the simultaneous data acquisition of 201Tl and 123I-metaiodobenzylguanidine provided the myocardial uptake rate of both tracers under the same pathological condition. (author)

54

Lung activity in 201Tl-myocardial scintigraphy: Distribution and correlation with hemodynamic parameters  

International Nuclear Information System (INIS)

The aim of this study was 1. to investigate whether the pulmonary activity in 201Tl myocardial scintigraphy can be accurately quantitied from the anterior SPECT projection, 2. to determine the pattern of the intrapulmonary Tl distribution, and 3. to assess the influence of parameters of left ventricular function on the lung/heart ratio (LHR). Scintigraphic images of 85 patients were analysed. In 24 patients planar anterior imaging of the thorax was performed in addition to myocardial SPECT, in 41 patients radionuclide ventriculography was performed with 4 weeks after Tl scintigraphy. In conclusion: 1. Pulmonary Tl-content can be quantitated from the anterior SPECT projection with sufficient accuracy, 2. a lower thallium activity was registered over the apical part of the lung as compared to the basal part, and 3. in the multiple regression analysis the left ventricular ejection fraction (LVEF) during exercise and heart rate during exercise (HRex) exhibit the strongest relation to LHR. After correction with regard to HRex the elevated LHR points to a pathological LVEF during exercise. (orig.)

55

Localization of post-infarction myocardial ischemia by 201Tl emission computed tomography  

International Nuclear Information System (INIS)

In 41 patients with a history of a single myocardial infarction, the location of myocardial ischemia was studied by 201Tl emission computed tomography immediately and 3 h after intravenous dipyridamole. Peri-infarctional ischemia without distant ischemia was observed in 15 patients. The occurrence of distant ischemia was found to be dependent on the severity of stenosis in non-infarct coronary vessels. Twelve (86%) of 14 patients with non-infarct stenosis of 75% or greater had distant ischemia, but only 1 (4%) of 27 patients with non-infarct stenosis of less than 75%. In the presence of distant ischemia, peri-infarctional ischemia was in 11 patients (85%) associated with collaterals supplying the infarct zone, whereas in 13 (87%) of the patients with peri-infarctional ischemia only, incomplete obstruction of the infarct vessel was observed. It is concluded that, by the distinction between peri-infarctional and distant ischemia, the presence of significant stenosis in non-infarct vessels can be non-invasively predicted from tomographic thallium scintigraphy with dipyridamole. (orig./MG)

56

Improvement of myocardial perfusion detected by 201Tl scintigraphy on cardiac rehabilitation for patients with coronary artery disease  

International Nuclear Information System (INIS)

The effect of cardiac rehabilitation (mean 70±48 months) on myocardial perfusion was assessed using thallium-201 (201Tl) exercise study in 63 patients with coronary artery disease (CAD). Subjects were those in a rehabilitation group (Rh=42) participating in supervised sports training two to three times per week and the control group (Ct=21) not taking active daily exercise. The interval between two 201Tl SPECT studies was 19±16 months. After physical training, total duration of the exercise test increased from 443±112 to 536±121 seconds (+19%) in the Rh group, and from 484±129 to 432±115 seconds in the Ct group (-10.7%) (p2 to 269.8±58 x 102 in the Rh group and decreased from 218.7±40 x 102 to 216.6±76 x 102 (p201Tl myocardial perfusion defect on exercise improved more in 54.8% (stress 59.5%, rest 35.7%) in the Rh group than in the Ct group (9.5%, p201Tl perfusion defect decreased from 68 (23.1%) to 49 regions (16.7%) of 294 total myocardial regions in the Rh group on exercise. However. it increased from 39 (26.5%) to 44 (29.9%) regions of 147 regions in the Ct group (p<0.01). Thus, cardiac rehabilitation increases exercise tolerance with improvement of myocardial perfusion. suggesting that cardiac rehabilitation is an advisable and effective treatment for patients with ischemic heartfor patients with ischemic heart disease. (author)

57

Noninvasive estimation of site of lesion of left anterior descending artery with stress 201Tl myocardial SPECT images  

International Nuclear Information System (INIS)

Noninvasive estimation of site of lesion of left anterior descending artery (LAD) is important because of high morbidity of LAD lesion. Utility of stress 201Tl myocardial SPECT images for predicting site of LAD lesion characteristics of ischemic region induced by LAD lesion in the basal coronal image were studied in 53 patients with localized significant LAD lesion. Right margin of ischemic region at basal plane of SPECT images was determined by circumferential maximum count profile analysis of stress 201Tl myocardial images. Right margin of ischemic region induced by the just proximal lesion was 21±11deg, that by proximal lesion was -6±10deg and that by mid portion was -36±17deg. Sensitivity of right margin of ischemic region 0 for just proximal lesion was 100% (20/20) and that of right margin of ischemic region 0 for mid portion lesion was 100% (18/18). These results showed the possibility of detecting site of LAD lesion by stress 201Tl myocardial SPECT images. (author)

58

Evaluation of the graft flow reserve after coronary artery bypass grafting by stress 201Tl myocardial SPECT. Comparison between arterial grafts and venous grafts  

International Nuclear Information System (INIS)

We performed stress 201Tl myocardial SPECT to evaluate ischemia and perfusion reserve after coronary artery bypass grafting (CABG). A total of 103 patients was performed stress 201Tl myocardial SPECT one month after CABG. Each patient's myocardium was divided into 9 segments and visually evaluated using five grade scoring system (0=defect, 1=severe decrease, 2=moderate decrease, 3=mild decrease, 4=normal uptake). Eleven of 133 (8.27%) segments covered by patent venous grafts showed reversible 201Tl defect, however, 36 of 117 (30.8%) segments which covered by patent arterial grafts showed reversible 201Tl defect. This finding was observed more significantly in arterial grafts than in venous grafts (p<0.001). These finding suggests that arterial grafts have lower flow capacity than venous grafts at peak exercise. (author)

59

Clinical assessment of myocardial viability by stress-reinjection 201Tl/rest 99mTc-MIBI dual-isotope imaging strategy  

International Nuclear Information System (INIS)

Objectives: To assess area and severity of myocardial ischemia and myocardial viability by dobutamine stress-reinjection 201Tl/ rest 99mTc-MIBI dual-isotope myocardial perfusion tomography. Methods: The study included 35 patients who underwent tress-reinjection 201Tl/ rest 99mTc-MIBI dual-isotope SPECT and coronary angiography (CAG). Dobutamine stress was carried out 20 min after 99mTc-MIBI was injected intravenously at rest, then 201Tl was administrated intravenously, and dual-isotope SPECT was performed instantly. Because both of stress 201Tl and rest 99mTc-MIBI imaging showed area of defect radioactivity, 1mCi 201Tl was reinjected at rest, dual-isotope SPECT was performed again 4 hours later. Results: (1) of 86 segments showing defected activity, 54 segments were fill with radioactivity and the other 32 segments were not improved after 201Tl was reinjected. (2) All of 35 patients, 9 patients were normal and 26 patients were abnormal by coronary angiography (one cronory artery stenosis in 2 patients, 2 coronary arteries stenosis in 7 patients, 3 coronary arteries stenosis in 17 patients.). There were 17 patients with 50-75% coronary stenosis, 3 patients with 75-85% coronary stenosis and 15 patients with more than 85% coronary stenosis. The stenosis coronary arteries detected by coronary angiography were consistent with those detected by tress-reinjection 201Tl/ rest 99mTc-MIBI dual-isotope SPECT. (3) Assessed byc-MIBI dual-isotope SPECT. (3) Assessed by stress-reinjection 201Tl/ rest 99mTc-MIBI dual-isotope SPECT, all ischemic cardiac muscles in 26 patients with CAD were viable. Of 26 CAD patients, 2 patients underwent PTCA, 2 patients underwent PCI, 6 patients underwent CABG in two or more vessels, 1 patient was treated with thrombolysis, the other 15 patients received medical treatment. (4) 14 segments with defect activity were detected by myocardial imaging in 9 normal patients by CAG. Of them, 5 segments were in lateral wall, 3 segments in anterior wall, 7 segments in septal wall near basement. 11 segments were fill with radioactivity after 201Tl were reinjected. Conclusion: Tress-reinjection 201Tl/ rest 99mTc-MIBI dual-isotope myocardial perfusion SPECT is an effective method for investigating area and severity of myocardial ischemia and myocardial viability and, have a dicision-making effect on CAD patient's treatment planning. (authors)

60

Evaluation of viability of infarcted myocardium by low dose dobutamine stress echocardiography. Comparison with exercise stress {sup 201}Tl myocardial scintigraphy  

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Exercise stress {sup 201}Tl myocardial single-photon emission computed tomography (SPECT) is recognized to be a excellent method for identifying viability after myocardial infarction, but it is expensive and needs a longer time for data acquisition than echocardiography. We therefore performed this study to evaluate the effectiveness of low dose (5-10 {mu}g/kg/min) dobutamine stress echocardiography (DSE) in 30 patients (61{+-}8 years old: 24 men and 6 women) within 4 weeks after myocardial infarction in identifying viable myocardium, compared to results obtained by SPECT. Defining an akinetic or dyskinetic segment obtained by rest echocardiography as a definite infarct area, altogether 96 segments out of 716 segments were shown to be infarct areas. Of these, 75 (78%) segments were identified as viable by DSE, and 77 (80%) by SPECT. Only 2 segments were shown to be discrepant on DSE and SPECT. Subsequently, the sensitivity, specificity and accuracy rates for DSE were 96%, 100% and 96%, respectively. In conclusion, DSE is as effective and useful as SPECT in the evaluation of viability after myocardial infarction. (author)

Nagahara, Toshihiro; Sakamoto, Kazunori; Sofue, Akira; Horiuchi, Toshimitsu; Yamazaki, Shigeki; Kuwako, Kenji [Teikyo Univ., Tokyo (Japan). Faculty of Medicine

1999-03-01

 
 
 
 
61

Scintigraphic appearance in stress 201Tl myocardial SPECT of midportion lesion in left anterior descending artery  

International Nuclear Information System (INIS)

Scintigraphic appearance of left anterior descending artery (LAD) lesion in stress 201Tl myocardial SPECT was studied in 43 patients with midportion lesion in LAD confirmed by coronary angiography. Right margin of ischemic region in the basal short axial image was -36±17deg and left margin was -128±75deg. In 28 of 43 patients left margin lied beyond -120deg. From the results it was concluded that in most cases basal inferior wall was perfused by septal branches from LAD. In 6 patients with midportion lesion situated proximal to the first diagonal branch and in 12 patients with midportion lesion situated proximal to the second diagonal branch ischemic region in the apical portion was noted at both septum and anterolateral wall. Critical short axial image, in which right margin of ischemic region shifted from plus to minus area, was the 3.2th short axial image in the former group and the 5.2th in the latter group (p<0.01). In 10 patients with midportion lesion situated distal to the large first diagonal branch, ischemic region was noted in septal wall and not in anterolateral wall. It was concluded that right margin of ischemic region in the basal coronal image was the most useful sign for predicting midportion lesion and left margin for dominancy between LAD and right coronary artery and that apical anterolateral ischemia was sign for LAD lesion involving diagonal branch. Critical short axial image was useful for determining whether the lesion was situatedermining whether the lesion was situated proximal or distal to the first diagonal branch and whether the lesion was situated proximal to the second diagonal branch. (author)

62

Evaluation of myocardial perfusion and left ventricular function by 201Tl scintigraphy after dipyridamole  

International Nuclear Information System (INIS)

201Tl myocardial imaging was performed at rest and after dipyridamole (0.44 mg/kg) on 50 patients with known or suspected ischemic heart disease. The dipyridamole had no effect in 14 patients (group Dip.0). In 17 patients (group Dip +-) it significantly modified the contrast of the rest image (by increasing or decreasing a rest perfusion defect). In 19 patients (group Dip - Steal) the drug induced a paradoxical response interpreted as a coronary steal effect (an active region at rest becomes hypoactive after dipyridamole while an underperfused region at rest improves). All patients underwent coronary arteriography and left monoplane ventriculography; results were interpreted in relation to these angiographic data. The mean percentage of stenoses (per patient) was about the same in the three groups but it was found that, despite these stenoses, the patients of the group Dip - Steal had a good left ventricular function (EF = 0.62 +- 0.12). On the other hand, the ejection fraction was very poor in the two other groups (0.50 +- 0.17 and 0.48 +- 0.17). Moreover it was found that: (1) the frequency of high grade or even complete obstruction was notably less in group Dip - Steal (P < 0.05); (2) the frequency of angiographically visible collaterals was higher in group Dip - Steal (P < 0.05); (3) the left anterior descending artery was less diseased than the right coronary artery in group Dip - Steal (P < 0.05). These results have a real prognostic value for the asss have a real prognostic value for the assessment of the preserved cardiac performance in Dip - Steal patients despite severe stenoses, and are discussed in terms of compensatory collateral circulation and preservation of the coronary-flow reserve in the myocardium distal to a critical stenosis. (orig.)

63

Effects of metabolically ischemic, but viable, myocardium on QT dispersion in patients with acute myocardial infarction. A study with resting I-123-BMIPP/thallium-201 myocardial single-photon emission computed tomography  

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In chronic Q-wave myocardial infarction, QT dispersion is closely correlated with infarct size, but this correlation has not been evaluated for acute myocardial infarction (AMI). The effects of abnormal fatty acid metabolism on QT dispersion were examined in 123 patients with AMI who underwent resting iodine-123-15-iodophenyl 3-methyl pentadecanoic acid (BMIPP)/thallium-201 ({sup 201}Tl) myocardial single photon emission computed tomography (SPECT) and electrocardiographic analysis in the subacute phase. The relationship between BMIPP and {sup 201}Tl was defined as match when the total defect score for BMIPP was equal to or smaller than that for {sup 201}Tl, and as mismatch when the total defect score for BMIPP was larger than that for {sup 201}Tl. Twenty-six patients (21%) demonstrated BMIPP-{sup 201}Tl match and 97 (79%) demonstrated mismatch. Infarct size was closely correlated with QT dispersion (r=0.67, p<0.001) in patients with BMIPP-{sup 201}Tl match, but weakly correlated (r=0.30, p<0.005) in patients with BMIPP-{sup 201}Tl mismatch. For small infarctions, QT dispersion was significantly larger in patients with BMIPP-{sup 201}Tl mismatch than in those with BMIPP-{sup 201}Tl match (62{+-}24 ms vs 41{+-}18 ms, p=0.03), but did not differ between the 2 groups for large infarctions. This study shows that QT dispersion is influenced by infarct size and by the presence of metabolically ischemic but viable myocardium in patients with AMI. (author)

Yamagishi, Hiroyuki; Toda, Iku; Akioka, Kaname; Hirata, Kumiko; Yoshiyama, Minoru; Teragaki, Masakazu; Takeuchi, Kazuhide; Yoshikawa, Junichi; Ochi, Hironobu [Osaka City Univ. (Japan). Medical School

2000-08-01

64

Characteristics of treadmill electrocardiography and dipyridamole 201Tl myocardial perfusion imaging in patients with coronary artery spasm  

International Nuclear Information System (INIS)

Objective: To investigate the characteristics of treadmill electrocardiography and dipyridamole 201Tl myocardial perfusion imaging in patients with coronary artery spasm, and to explore a non-invasive procedure for diagnosing coronary artery spasm. Methods: The patients who had chest pain but no significant coronary artery stenosis and were willing to undergo acetylcholine test were included. Treadmill electrocardiography, dipyridamole and rest 201Tl myocardial perfusion computed tomography were performed before or after coronary angiography. The relationship between the results of above mentioned stress tests and coronary spasm was investigated. Results: Acetylcholine test was performed on all the 52 patients and provoked coronary artery spasm in 42 patients of them. Rest chest pain with oppression was clinically remarkable in those patients with coronary artery spasm, which was different from effort chest pain in patients with significant coronary stenosis, but twinge without stable relation to effort or rest was the main clinical manifestation in non-spasm and non-stenosis patients. Ischemic change on electrocardiogram was induced during treadmill electrocardiography in only 3 patients of the study group and no ischemic changes in the remaining 49 patients. Reverse redistribution on 201Tl myocardial perfusion imaging was noticed in 48 patients. The sensitivity and specificity of predicting coronary artery spasm by reverse redistribuoronary artery spasm by reverse redistribution were 100% and 40%, respectively. To predict coronary artery spasm by combination of reserve redistribution, rest chest pain with oppression and negative treadmill electrocardiogram, the sensitivity remained at 98% but the specificity increased to 90%. Conclusions: Reserve redistribution might be one of the characteristics of coronary artery spasm. The combination of reserve redistribution, rest chest pain with oppression and negative treadmill electrocardiogram might be a rational non-invasive method to predict coronary artery spasm. (authors)

65

Accuracy of serial myocardial perfusion scintigraphy with 201Tl for prediction of graft patency early and late after coronary artery bypass surgery. A controlled prospective study  

International Nuclear Information System (INIS)

To assess the accuracy of serial myocardial perfusion scintigraphy with 201Tl to predict graft patency early and late coronary artery bypass surgery, rest and exercise 201Tl and coronary arteriography were performed preoperatively and 2 weeks and 1 year after operation. The scintigraphic results were compared with graft patency, symptoms, left ventricular function and physical work capacity in a consecutive series of 55 patients with a total of 154 grafts. Serial 201Tl had an 80% sensitivity, 88% specificity and 86% overall accuracy in detecting or excluding graft occlusion, which was predicted by reversible ischemia as well as persistent new scar segments. Occluded grafts were correctly localized by 201Tl scintigraphy in 61%. Postoperative apical 201Tl defects were frequent (two-thirds of cases), and were the result of intraoperative transapical venting of the left ventricle. After coronary bypass graft surgery, ejection fraction at rest was unchanged. Left ventricular end-diastolic pressure and physical work capacity improved significantly. In the presence of new perfusion defects detected postoperatively, physical work capacity was reduced significantly. New 201Tl defects in addition to typical or atypical angina provided a high probability of graft occlusion, while in the absence of new 201Tl defects all grafts were patent in more than 90% of patients, all of whom had no or only atypical ents, all of whom had no or only atypical chest pain. We conclude that serial 201Tl imaging after coronary artery bypass surgery is an accurate noninvasive method that can be used routinely to assess graft function, to localize spatially occluded grafts and to identify patients with a high likelihood of graft occlusion who may need invasive studies

66

Comparison of adenosine stress and exercise stress 201Tl myocardial perfusion imaging for diagnosis of coronary heart disease  

International Nuclear Information System (INIS)

Objective: The aim of this study was to compare the diagnostic values of adenosine and exercise stress 201Tl myocardial perfusion imaging for detecting coronary heart disease (CHD). Methods: 41 patients with suspected CHD were randomly divided into two groups. In one group adenosine stress was submitted, the exercise stress myocardial SPECT was performed in another. Coronary angiography (CAG) was performed in each patient within 2 weeks before or after SPECT. The result of CAG was taken as 'gold standard of CHD. They compared the diagnostic value of two methods. Results: In adenosine group, the sensitivity, specificity, positive predictive value, negative predictive value, accuracy are 92.86%, 57.14%, 81.25%, 80.00%, 80.95% respectively. In exercise stress group, are 100%, 60.0%, 71.43%, 100%, 80.00% respectively. Detection rates of coronary artery lesions were 66.67% and 72.22% in two groups respectively. Conclusion Adenosine stress testing and exercise stress testing 201Tl myocardial perfusion imaging may provide similar value for detection of CHD. (authors)

67

Comparison of correction techniques for simultaneous {sup 201}Tl/{sup 99m}Tc myocardial perfusion SPECT imaging: a dog study  

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We compared two correction methods for simultaneous {sup 201}Tl/{sup 99m}Tc dual-isotope single-photon emission computed tomography (SPECT). Both approaches use the information from the third energy window placed between the photopeak windows of the {sup 201}Tl and {sup 99m}Tc. The first approach, described by Moore et al, corrects only for the contribution of the {sup 99m}Tc to the {sup 201}Tl primary 70 keV window. We developed the three-window transformation dual-isotope correction method, which is a simultaneous cross-talk correction. The two correction methods were compared in a simultaneous {sup 201}Tl/{sup 99m}Tc sestamibi cardiac dog study. Three separate acquisitions were performed in this dog study: two single-isotope and one dual-isotope acquisition. The {sup 201}Tl single-isotope images were used as references. The total number of counts, and the contrast between the left ventricular cavity (LVC) and the myocardium, were used in 70 keV short-axis slices as parameters for evaluating the results of the dual-isotope correction methods. Three consecutive short-axis slices were used to calculate averaged contrast and the averaged total number of counts. The total number of the counts was 667 000 {+-} 500 and 414 500 {+-} 400 counts for the dual-isotope ({sup 201}Tl + {sup 99m}Tc) and single-isotope ({sup 201}Tl-only) 70 keV images, respectively. The corrected dual-isotope images had 514 700 {+-} 700 and 368 000 {+-} 600 counts for Moore's correction and our approach, respectively. Moore's method improved contrast in the dual-isotope 70 keV image to 0.14 {+-} 0.03 from 0.11 {+-} 0.02, which was the value in the 70 keV non-corrected dual-isotope image. Our method improved the same contrast to 0.22 {+-} 0.03. The contrast in the {sup 201}Tl single-isotope 70 keV image was 0.28 {+-} 0.02. Both methods improved the 70 keV dual-isotope images. However, our approach provided slightly better images than Moore's correction when compared with {sup 201}Tl-only 70 keV images. (author)

Knesaurek, Karin; Machac, Josef [Division of Nuclear Medicine, The Mount Sinai Medical Center, New York (United States)

2000-11-01

68

Coronary flow reserve evaluated by 201Tl myocardial perfusion SPECT after coronary artery bypass grafting (CABG) for angina pectoris  

International Nuclear Information System (INIS)

We compared the flow reserves of the coronary bypass vessels between arterial and venous grafts by 201Tl myocardial perfusion SPECT on the patients with angina pectoris who had no past history of myocardial infarction or intervention therapy such as PTCA. Thirty two patients had undergone a total of 70 bypass grafts and 66 of them were proved to be patent at postoperative CAG. Reversible defects were observed in 6 of 40 segments (15.0%) covered by patent venous grafts, and in 11 of 26 segments (42.3%) by patent arterial grafts. The rate of postoperative reversible defects was higher in the areas grafted by artery but this had no relation with the severity of coronary artery stenosis before CABG. This reversible defect is most likely to be caused by the character of artery graft itself and this should not be considered to highly suggest the restenosis or occlusion of the graft vessel. (author)

69

Coronary flow reserve evaluated by {sup 201}Tl myocardial perfusion SPECT after coronary artery bypass grafting (CABG) for angina pectoris  

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We compared the flow reserves of the coronary bypass vessels between arterial and venous grafts by {sup 201}Tl myocardial perfusion SPECT on the patients with angina pectoris who had no past history of myocardial infarction or intervention therapy such as PTCA. Thirty two patients had undergone a total of 70 bypass grafts and 66 of them were proved to be patent at postoperative CAG. Reversible defects were observed in 6 of 40 segments (15.0%) covered by patent venous grafts, and in 11 of 26 segments (42.3%) by patent arterial grafts. The rate of postoperative reversible defects was higher in the areas grafted by artery but this had no relation with the severity of coronary artery stenosis before CABG. This reversible defect is most likely to be caused by the character of artery graft itself and this should not be considered to highly suggest the restenosis or occlusion of the graft vessel. (author)

Ishino, Yoichi; Nakata, Hajime [Univ. of Occupational and Environmental Health, Kitakyusyu, Fukuoka (Japan)

2000-11-01

70

Serial 201Tl myocardial imaging after dipyridamole infusion: diagnostic utility in detecting coronary stenoses and relationship to regional wall motion  

International Nuclear Information System (INIS)

After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial 201Tl scans were obtained in 60 patients undergoing cardiac catheterization. Forty patients had significant (greater than or equal to 50% stenosis) coronary artery disease (CAD), and 20 patients had normal coronary arteries or trivial lesions. The images were graded qualitatively for thallium activity by three observers. Sensitivity was 93% (37 of 40) and specificity was 80% (16 of 20). The sensitivity and specificity of the 201Tl study were not affected by the extent of CAD, the presence of Q waves, or propranolol therapy. Twenty-seven of 37 patients who had initial defects (73%) had complete thallium redistribution of one or more defects. Patient-by-patient analysis using a regression model of all patients showed that the fate of a segmental thallium defect predicted abnormal wall motion by angiography better than ECG Q waves. The presence of propranolol therapy or collaterals did not significantly affect the thallium redistribution results. We conclude that qualitative interpretation by multiple observers of thallium images after dipyridamole infusion is a highly sensitive and specific test for CAD. After dipyridamole, as with exercise stress, the extent of thallium redistribution is related to the degree of myocardial wall motion abnormality

71

Myocardial gammagraphy with 201Tl chloride in diagnosis of ischaemic heart disease  

International Nuclear Information System (INIS)

In a group of 60 patients, the diagnostic reliability was compared of perfusion gammagraphy of the heart muscle with 201Tl chloride at exercise and of the ECG exercise test, with that of X-ray coronarography as the standard diagnostic method for ischaemic heart disease. The method of thallium perfusion gammagraphy of the heart muscle was as to its effectiveness very close to the method of standard diagnosis and its results in the diagnosis of ischaemic heart disease were significantly better than the results of the ECG exercise test. (author)

72

Double myocardial scintigraphy with thallium 201 (Tl) and technetium containing pyrophosphate (PYP) in acute thrombosis  

International Nuclear Information System (INIS)

Tests were carried out with thallium 201 (Tl) and technetium containing pyrophosphate (PYP) to compare their diagnostic sensitivity and estimate their possibilities for thrombosis size determinations. The study shows that double scintigraphy (Tl+PYP) supplies information on the size of the necrosis and promises more precise quantification, an important point considering the relationship which exists between the size of a thrombosis and the clinical prospects. PYP appears more sensitive than Tl, especially for non-transmural necroses and small thromboses. The diagnostic value of PYP is greater than that of Tl during the subacute phase

73

123I-MIBG myocardial scintigraphy in diabetic patients. Relationship with 201Tl uptake and cardiac autonomic function  

International Nuclear Information System (INIS)

The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by 201Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after 123I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of 123I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the 201Tl image and the 123I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score (?TUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of tcant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding ?TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for ?TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. (K.H.)

74

{sup 123}I-MIBG myocardial scintigraphy in diabetic patients. Relationship with {sup 201}Tl uptake and cardiac autonomic function  

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The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by {sup 201}Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after {sup 123}I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of {sup 123}I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the {sup 201}Tl image and the {sup 123}I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score ({Delta}TUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding {Delta}TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for {Delta}TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. (K.H.)

Nagamachi, Shigeki; Jinnouchi, Seishi; Kurose, Takeshi; Ohnishi, Takashi; Flores, L.G. II; Nakahara, Hiroshi; Futami, Shigemi; Tamura, Shozo; Matsukura, Shigeru [Miyazaki Medical Coll., Kiyotake (Japan)

1998-12-01

75

[sup 123]I-MIBG myocardial scintigraphy in diabetic patients. Relationship with [sup 201]Tl uptake and cardiac autonomic function  

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The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by [sup 201]Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after [sup 123]I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of [sup 123]I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the [sup 201]Tl image and the [sup 123]I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score ([Delta]TUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding [Delta]TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for [Delta]TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. (K.H.)

Nagamachi, Shigeki; Jinnouchi, Seishi; Kurose, Takeshi; Ohnishi, Takashi; Flores, L.G. II; Nakahara, Hiroshi; Futami, Shigemi; Tamura, Shozo; Matsukura, Shigeru (Miyazaki Medical Coll., Kiyotake (Japan))

1998-12-01

76

Estimation of infarct size by myocardial emission computed tomography with 201Tl and its relation to creatine kinase-MB release after myocardial infarction in man  

International Nuclear Information System (INIS)

We evaluated emission computed tomography (ECT) 201Tl myocardial imaging in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar 201Tl perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of 201Tl perfusion defects, the infarct area in planar images and the infarct volume in reconstructed ECT images were measured by computerized planimetry. When scintigraphic IS was compared with the accumulated creatine kinase-MB isoenzyme release (CK-MBr), infarct volume determined from ECT correlated closely with CK-MBr (r . 0.89), whereas infarct area measured from planar images correlated less satisfactorily with the enzymatic IS (for an average infarct area from three views, r . 0.69; for the largest infarct area, r . 0.73). Although conventional scintigraphic evaluation is useful for detecting and localizing infarction, quantification of ischemic injury with this two-dimensional technique has a significant inherent limitation. The ECT approach can provide a more accurate three-dimensional quantitative estimate of infarction, and can corroborate the enzymatic estimate of IS

77

assessment of the clinical role of simultaneous 99mTc-MIBI and 201Tl dual-isotopic myocardial perfusion SPECT imaging in the patients wit hypertension  

International Nuclear Information System (INIS)

Objective: To study the clinical role of Simultaneous rest technetium-99m sestamibi (99mTc-MIBI) and stress thallium-201 (201Tl) Dual-isotopic myocardial perfusion SPECT imaging in the patients with hypertension. Methods: 116 patients with high blood pressure underwent simultaneous dual-isotopic myocardial perfusion SPECT imaging with 99mTc-MIBI and 201Tl. 99mTc-MIBI was injected at rest, 15 min later dobutamine was instilled into vein begin with 5 mg/kg/min, before and after instilling the base ECG, blood pressure, heart rate was recorded. when the maximal dose of Dobutamine was achieved, thallium-201 was injected, the dual-isotopic simultaneously SPECT imagine was performed. The stress and rest imagine was obtained. After tomographic reconstruction, the images were interpreted by two experienced observers without previous knowledge of results of other studies. Coronary angiography was performed in two weeks. All of 116 patients were found normal. Results: (1) All of 116 patients with high blood pressure were divided as three group by the course of disease: A group (20 year), 15. The heart/lung ratios of A, B, C group were 2.651±0.246, 2.546±0.231, 2.490±0.36 (mean±SD)respectively, no significant difference was noted among three group. Normal heart/lung ratios is 2.50±0.28 among of control group of 20. (2) The overall sensitivity for the dual-isotopic simultaneously myocardial SPECT opic simultaneously myocardial SPECT imagine of high blood pressure was 46.55%(54/116). (3) Anterior, lateral, inferior, apex, interventricular septal segment were regarded as a whole segment, 111 segments display abnormal 201Tl uptake. 63, 30, 18 segments were in A, B, C group respectively, and no significant difference was noted among three group. 4 85 segments reveal reduced stressing 201Tl uptake and no typical redistribution was observed in the delay 201Tl imagines. 20, 24, 14, 12, 15 segments were in anterior, lateral, inferior, apex, interventricular septal segment respectively. 26 segments display inverse 201Tl redistribution, 2, 14, 3, 3, 4 segments were m anterior, lateral, inferior, apex, interventricular septal segment respectively. 5 all rest 99mTc-MIBI imagines display normal uptake. Conclusion: Simultaneous rest 99mTc-MIBI and stress 201Tl dual-isotopic myocardial perfusion SPECT imaging is an effective auxiliary method in the detection of hypertension and identification of Coronary Artery Disease. (authors)

78

Absolute quantitation of myocardial blood flow with {sup 201}Tl and dynamic SPECT in canine: optimisation and validation of kinetic modelling  

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{sup 201}Tl has been extensively used for myocardial perfusion and viability assessment. Unlike {sup 99m}Tc-labelled agents, such as {sup 99m}Tc-sestamibi and {sup 99m}Tc-tetrofosmine, the regional concentration of {sup 201}Tl varies with time. This study is intended to validate a kinetic modelling approach for in vivo quantitative estimation of regional myocardial blood flow (MBF) and volume of distribution of {sup 201}Tl using dynamic SPECT. Dynamic SPECT was carried out on 20 normal canines after the intravenous administration of {sup 201}Tl using a commercial SPECT system. Seven animals were studied at rest, nine during adenosine infusion, and four after beta-blocker administration. Quantitative images were reconstructed with a previously validated technique, employing OS-EM with attenuation-correction, and transmission-dependent convolution subtraction scatter correction. Measured regional time-activity curves in myocardial segments were fitted to two- and three-compartment models. Regional MBF was defined as the influx rate constant (K{sub 1}) with corrections for the partial volume effect, haematocrit and limited first-pass extraction fraction, and was compared with that determined from radio-labelled microspheres experiments. Regional time-activity curves responded well to pharmacological stress. Quantitative MBF values were higher with adenosine and decreased after beta-blocker compared to a resting condition. MBFs obtained with SPECT (MBF{sub SPECT}) correlated well with the MBF values obtained by the radio-labelled microspheres (MBF{sub MS}) (MBF{sub SPECT} = -0.067 + 1.042 x MBF{sub MS}, p < 0.001). The three-compartment model provided better fit than the two-compartment model, but the difference in MBF values between the two methods was small and could be accounted for with a simple linear regression. Absolute quantitation of regional MBF, for a wide physiological flow range, appears to be feasible using {sup 201}Tl and dynamic SPECT. (orig.)

Iida, Hidehiro; Kim, Kyeong-Min; Nakazawa, Mayumi; Sohlberg, Antti; Zeniya, Tsutomu; Hayashi, Takuya; Watabe, Hiroshi [National Cardiovascular Center Research Institute, Department of Investigative Radiology, Suita City, Osaka (Japan); Eberl, Stefan [National Cardiovascular Center Research Institute, Department of Investigative Radiology, Suita City, Osaka (Japan); Royal Prince Alfred Hospital, PET and Nuclear Medicine Department, Camperdown, NSW (Australia); Tamura, Yoshikazu [Akita Kumiai General Hospital, Department of Cardiology, Akita City (Japan); Ono, Yukihiko [Akita Research Institute of Brain, Akita City (Japan)

2008-05-15

79

Double-nuclide study of the myocardium using 201Tl and 123I-labeled fatty acids in non-ischemic myocardial diseases  

International Nuclear Information System (INIS)

Metabolic impairment and perfusion abnormalities are known to occur in hypertensive heart disease (HHD) and in cardiomyopathies. Free fatty acid (FFA) extraction is severely inhibited in a number of pathobiochemical reactions. This parameter was assessed using the radiolabeled FFA analogue 123I-(p-iodo-phenyl-)-pentadecanoic acid (IPPA) and 201Tl as perfusion marker, both of them injected at maximal physical workload. The regional extraction fraction of IPPA (IPPA-EF) was estimated by relating the regional IPPA and 201Tl uptake to each other. In HHD (normal coronary arteries) with posterior wall thickness ?12 mm IPPA-EF was 77 ± 18% (SD) in septum and 92 ± 17% in the posterolateral wall (N = 13), with thickness of >12 mm 60 ± 23% in septum and 61 ± 20% in the posterolateral wall (N = 8) when compared with IPPA-EF in normal subjects (= 100%, N = 9). In hypertrophic cardiomyopathy (HCM) IPPA-EF averaged 51 ± 20% in septum and 87 ± 10% in the posterolateral wall (N = 11). In these patient groups no systematic regional changes in 201Tl uptake were observed. In dilated cardiomyopathy (DCM) both IPPA-EF and 201Tl uptake showed distinct regional variations and a great interindividual variability with a mean IPPA-EF reduction of 12% (N = 9). Thus, IPPA uptake in primarily non-ischemic myocardial disease may already be compromised when 201Tl uptake is unchanged. The double-nuclide method for IPPA-EF detele-nuclide method for IPPA-EF determination allows to eliminate the influence of flow in FFA imaging and enhances the potential of scintigraphy in the differential diagnosis of HHD versus coronary artery disease. (orig.)

80

sup(99m)Tc-pyrophosphate and 201Tl myocardial scintigrams in a patient with myocarditis  

International Nuclear Information System (INIS)

Myocardial necrosis in acute myocarditis was investigated by scintigraphy. sup(99m)Tc-pyrophosphate (PYP) and 201TI myocardial scintigrams were obtained on a patient with acute myocarditis due to mycoplasma infection. sup(99m)Tc-PYP myocardial scintigrams in the acute stage demonstrated grade 2+ findings, which remained until the chronic stage. 201TI myocardial scintigrams in the acute stage revealed impaired perfusion restricted to the posterolateral wall, and this decrease continued through the chronic stage. It was concluded that both of sup(99m)Tc-PYP and 201TI myocardial scintigrams can reveal abnormality of acute myocarditis. (Ueda, J.)

 
 
 
 
81

Dual-isotope SPET201Tl rest/99Tc-MIBI stress: One-day protocol for pre-operative myocardial imaging?  

International Nuclear Information System (INIS)

We compared the results of a rest 201Tl/stress 99mTc-MIBI protocol, both by means of separate single isotope and simultaneous dual isotope acquisition, with a standard stress/rest 99mTc-MIBI 2-day protocol in 11 patients with low probability of CAD and 14 patients with chronic CAD. In patients with CAD 406 segments (sgs) were analysed. In the standard protocol 119 sgs were classified as pathological of which 50.4% were fixed and 49.6% reversible defects. With the MIBI-stress/Tl-rest single 33% of 119 pathological sgs were fixed and 67% reversible defects. With the MIBI-stress/Tl-rest dual only 20% were fixed and 80% reversible defects. The reversibility of 59 MIBI-stress/MIBI-rest reversible defects was quantified: MIBI-stress/MIBI-rest 35 ± 16% MIBI-stress/Tl-rest single 50 ± 26% and MIBI-stress/Tl-rest dual 48 ± 22%. The results of 99mTc-MIBI rest and 201Tl rest studies in patients with chronic CAD are not the same. Dual-isotope 1-day 201Tl-rest/99mTc-MIBI-stress SPET data, acquired separately, may give fast and complete information on myocardial perfusion at stress and rest, respectively, and on myocardial viability. (orig.)

82

Estimation of perioperative myocardial infarction in patients under aorto-coronary bypass grafts with plasma level of myosin light chain I and 201Tl SPECT  

International Nuclear Information System (INIS)

After aorto-coronary bypass grafts surgery plasma level of myosin light chain I, determined with monoclonal antibodies to myosin light chain I (LC-I), were studied in 12 patients (pts) without electrocardiographical perioperative myocardial infarction. Rest 201Tl myocardial images were collected before and after surgery. LC-I increased and reached peak levels (15±7 ng/ml) at 91±29 minutes after the aortic declamp. From peak levels LC-I rapidly decreased with fast half-time disappearance (1.4±0.9 hours). In 5 pts of 12 pts LC-I recovered to normal range and MB reached maximum levels (34±23 IU/L) at 18±9 hours after declamp. In 4 pts 201Tl images showed no changes. In 7 pts of 12 pts LC-I decreased to minimum levels (2.7±0.6 ng/ml) at 12±6 hours and then gradually increased to peak levels (5.6±0.9 ng/ml) on day 3±0.9. MB reached maximum level (61±20 IU/L) at 3.2±1 hours. In 201Tl images 3 pts showed suspected new lesion, 2 pts showed no changes and 2 pts showed improvement. No correlation was noted between peak LC-I level and duration of aortic declamp. No significant relation was suspected between early LC-I peak and irreversible myocardial cell injury. From close relationship between aortic declamp and appearance of LC-I peak, it was concluded that LC-I, accumulated during aortic clamp, was washed out by aortic declamp. Relation was suspected between ealy LC-I peak and myocardial injury during myocardial protection. Late LC-myocardial protection. Late LC-I peak may be useful for estimation of perioperative irreversible myocardial injury. (author)

83

Estimation of systemic lysis of acute myocardial infarct by radionuclide ventriculography and by 201Tl myocardial scintigraphy using also emission computed tomography  

International Nuclear Information System (INIS)

First experiences with fibrinolysis treatment by continuous streptokinase infusion for reopening of coronary arteries closed by thrombus in 28 patients with acute myocardial infarct are reported. The success of treatment is proved by means of the 201Tl myocardial scintigraphy as well as by ventriculoscintigraphy with /sup 99m/Tc-erythrocytes after homogeneous distribution of activity. In ventriculoscintigraphy both quantitative parameters (ejection fraction, maximum filling and evacuation rate) and wall motility disturbances of the left ventricle are proved. Similar results are gained with both the noninvasive methods completing each other. The therapeutic effect of the systemic lysis was statistically significant in the infarction of the anterior wall but not in that of the posterior wall. (author)

84

Measurement of myocardial uptake rate and method of dual energy data acquisition in myocardial scintigraphy with 123I-metaiodobenzylguanidine and 201Tl-chloride, 2  

International Nuclear Information System (INIS)

Myocardial scintigraphy was performed on 24 patients with hypertrophic cardiomyopathy (HCM), 5 with essential hypertension (EHT) and 7 normal controls at rest by means of simultaneous dual energy data acquisition following an intravenous injection of 123I-metaiodobenzylguanidine (MIGB) and 201Tl-chloride (Tl). The myocardial uptake rates of both tracers were measured in the planar images by taking into account the myocardial and pulmonary attenuation. The regional myocardial distributions of the tracers were also studied in the SPECT images. In planar images, the rate of loss of 123I-MIBG from the myocardium of HCM subjects was significantly higher than of control subjects 15 min to 3 hr after injection. No significant difference was observed from 3 hr to 5 hr and from the 5 hr to 21 hr periods. In the SPECT images, the rate of loss of 123I-MIBG from the myocardium of HCM subjects was significantly higher than of control subjects in all segments of myocardium through a 15 min to 5 hr observation period. The results suggested that the uptake-release mechanism of 123I-MIBG in the neuronal vesicles was impaired in HCM subjects in two different ways: (1) normal release in delayed phase associated with low uptake in early phase or (2) accelerated release in early phase. Moreover, the sympathetic dysfunction may spread through the all segments of myocardium of HCM subjects. The apical lesion showed an extremely high ratapical lesion showed an extremely high rate of loss up to 5 hr after injection in SPECT images. This was quite different from that of the septal lesion. This indicated that the apical lesion of HCM subjects may have a different sympathetic abnormality. In EHT subjects, no abnormal regional distribution of 123I-MIBG was observed. This suggested that the sympathetic innervation was maintained although an abnormal distribution of blood flow was frequently observed in 201Tl scintigraphy. (author)

85

Defect of {sup 18}F-FDG Uptake Observed in Infarcted Myocardium Showing Reverse Redistribution on Rest / 24-Hour Delayed {sup 201}Tl Myocardial SPECT after Acute Myocardial Infarction  

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Reverse redistribution is frequently observed after revascularization in acute myocardial infarction, and usually regarded as a predictor of viable myocardium on stress/rest and 2- to 4-hour redistribution {sup 201}Tl SPECT. However, there is not enough report of reverse redistribution in case of 24-hour delayed SPECT, which is commonly used for viability assessment. In this report, a case of reverse redistribution on rest and 24-hour delayed {sup 201}Tl SPECT is reported with use of automatic segmental quantitative analysis. The myocardium of reverse redistribution was dysfunctional on gated SPECT, and diagnosed as non-viable on {sup 18}F-FDG PET.

Lee, Ho Young; Paeng, Jin Chul; Oh, So Won; Kim, Ji Yeong; Chung, Woo Young [Seoul national University College of Medicine, Seoul (Korea, Republic of)

2008-12-15

86

Quantitative evaluation of serial 201-Tl myocardial scintigrams after stress testing in ischemic heart disease  

International Nuclear Information System (INIS)

Eight normal adults and forty-two patients with ischemic heart disease were studied by stress testing. Myocardial scintigrams in three views (anterior, left anterior oblique and left lateral projectons) were obtained at ten minutes, one and two hours (phase 0,1 and 2) after the 201-T1 bolus injection. The myocardial wall was geometrically divided into five segments each view. The washout rate from phase i to j(WRij) was defined as WRij = (maxCtsi - maxCtsj) /maxCtsi where maxCtsi denoted maximal Cts at phase i in the relevant view. The washout rate 02 (WR02) showed the decreasing rate of the net rate of 201-T1 for two hours after the injection. The redistribution index (cRdsij) in each segment was defined as cRdsij = [Ctsi x WRij + (Ctsj - Ctsi)]/maxCtsi, where Ctsi denoted mean Cts at phase i in the segment. cRds02 showed the redistributed counts which were estimated by adding WR02 for two hours. ?cRdsij denoted the sum of 15 cRdsij. MaxcRdsij indicated as the maximum of 15 cRdsij. RI angiography was also performed in the twenty-eight cases who had myocardial scintigram under stress testing. In conclusion, the redistribution index (cRds02) was helpful in quantitative assessment of the ischemic segments. And ?cRds02 was also helpful in the evaluation of ischemic heart disease. The finding that WR12 was greater than WR01 after the stress was reliable in suggesting transient myocardial ischemia. The evaluation of ischemic heart disease using ?cRds02 and EF was usefuldisease using ?cRds02 and EF was useful, in particular the evaluation of LV function in old myocardial infarction with angina and without angina. (J.P.N.)

87

Evaluation of left ventricular eccentric hypertrophy by /sup 201/Tl-myocardial scintigraphy  

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In order to elucidate the mechanism of left ventricular eccentric hypertrophy in conditions of volume overload, Tl-201 myocardial scintigraphy was performed in patients with aortic valve regurgitation and mitral valve regurgitation. There was a good relationship between the severity of Tl-defects, as determined by Tl-201 myocardial scintigraphy, and the changes in the T wave on the ECG on the one hand and the NYHA functional classification of heart diseases. In 17 of 18 patients where LVDd increased with increasing severity of Tl-defects and the defects were moderate to severe, LVDd was 65 mm or larger. There was a significant negative correlation between the washout rate for the whole circumference of the left ventricle, as determined by exercise Tl-201 SPECT, and LVDd (r=-0.603, p<0.01). The phenomenon of redistribution as determined by exercise Tl-201 myocardial scintigraphy was observed relatively early. Our results suggest that mechanical volume overload and ischemic changes are involved in left ventricular wall damage in left ventricular eccentric hypertrophy. For patients with moderate to severe Tl-defects valve replacement is indicated, no matter whether they may have heart failure or arrhythmia.

Yamazaki, Junichi; Kawamura, Yasuaki; Okuzumi, Ichio; Morishita, Takeshi; Koyama, Nobuya; Komatsu, Hisashi; Ohsawa, Hidefumi; Yabe, Yoshimasa

1989-03-01

88

Dobutamine stress thallium-201 single-photon emission tomography versus echocardiography for evaluation of the extent and location of coronary artery disease late after myocardial infarction  

International Nuclear Information System (INIS)

Dobutamine stress echocardiography and thallium-201 myocardial perfusion scintigraphy are clinically useful methods for the evaluation of coronary artery disease (CAD). However, the relative merits of these imaging modalities in the evaluation of the extent of CAD after myocardial infarction have not been well studied. The aim of this study was to compare the accuracy of dobutamine stress echocardiography and simultaneous 201Tl single-photon emission tomography (SPET) imaging for the diagnosis and localization of CAD late after acute myocardial infarction. Dobutamine (up to 40 ?g kg-1 min-1)-atropine (up to 1 mg) stress echocardiography in conjunction with stress-reinjection 201Tl SPET was performed for the evaluation of myocardial ischaemia in 90 patients with previous myocardial infarction who underwent coronary angiography. Significant CAD was predicted on bases of myocardial ischemia (new or worsening wall motion abnormalities on echocardiography and reversible perfusion defects on 201Tl SPET). Significant CAD (? 50% luminal diameter stenosis) was detected in 73 (81%) patients. The sensitivity, specificity and accuracy of echocardiography in detecting remote ischaemia for the diagnosis of remote CAD (present in 53 patients) were, respectively, 79% (CI 70%-88%), 85% (CI 77%-93%) and 81% (CI 73%-90%), while the corresponding figures for 201Tl SPET were 75% (CI 66%-85%), 78% (CI 69%-87%) and 76% (CI 66%-85%), 78% (CI 69%-87%) and 76% (CI 67%-86%) respectively (P = NS vs echocardiography). The sensitivity, specificity and accuracy of echocardiography in detecting peri-infarction ischaemia for the diagnosis of infarct-related artery stenosis (present in 70 patients) were, rspectively, 77% (CI 68%-86%), 85% (CI 78%-92%) and 79% (CI 70%-87%) while the corresponding figures for 201Tl SPET were 73% (CI 64%-82%), 85% (CI 78%-92%) and 76% (CI 67%-84%) respectively (P = NS vs echocardiography). The agreement between the two methods for the diagnosis of peri-infarction and remote ischaemia was 70% (kappa = 0.37) and 80% (kappa = 0.59) respectively. It is concluded that dobutamine stress echocardiography and 201Tl SPET have comparable accuracy for the diagnosis of infarct related and remote CAD in patients with previous myocardial infarction. The agreement between the methods is higher for the diagnosis of remote CAD than for that of peri-infarction ischaemia. (orig.)

89

Clinical studies on thallium-201 myocardial single-photon emission computed tomography in patients with ischemic heart disease  

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In order to evaluate briefly the relative 3-dimensional distribution of 201Tl in the myocardium, a 2-dimensional polar map was developed from short axis tomograms of single-photon emission computed tomography (SPECT) using circumferential profile analysis. The data collected from 180 deg rotational scan around a body were used in clinical study to acquire the projection data in a short time, although, with a heart phantom study, there was more uniformity with the 360 deg collection than with 180 deg collection. So, the polar map of relative distribution and % washout rate (% WR) were created from 180 deg data collection. To detect ischemic area, the lower limit (M-SD) of the profile curve in 10 normal subjects was processed and compared with that of patients. Then, abnormal 201Tl distribution and % WR were identified comparing each patient's profile with the corresponding normal lower limits. In 24 patients with myocardial infarction, defect score (DS), estimated as infarcted size from the relative polar map, was compared with the size of abnormal wall motion in left ventriculography. There was a good correlation (r = 0.834) between them. Also, there were close correlations between DS and regional contraction (r = -0.869), and between DS and left ventricular ejection fraction (r = -0.775) respectively. In 24 patients with non-MI angina pectoris, the diagnostic sensitivity of exercise induced ischemia was 65 % and accuracy was 76 % by relative dis65 % and accuracy was 76 % by relative distribution map. However, the sensitivity of % WR map was superior (84 %) to that of relative map, especially in the patients with mild ischemia and multi-vessel disease. In conclusion, this comprehensive polar map method represented well a 3-dimensional myocardial distribution of 201Tl. The clinical usefulness in determination of infarct size and in diagnosis of myocardial ischemia were evaluated. (author)

90

Aspects of recovery from regional wall motion abnormalities after exercise in patients with ischemic heart disease using 201Tl myocardial dynamic SPECT  

International Nuclear Information System (INIS)

Using 201Tl myocardial dynamic SPECT (dynamic SPECT), we studied various aspects of the recovery from exercise-induced ischemia, particularly the mechanism of delayed recovery from wall motion abnormality. The subjects were 23 patients with ischemic heart disease who underwent coronary angiography, exercise stress two-dimensional echocardiography (ESE), and dynamic SPECT. Using a 3-head SPECT system, dynamic SPECT was performed for 33 min consecutively from 5 min after the intravenous injection of 201TlCl (Tl). The regional early washout rate (early WR) was determined at 20, 29, and 38 min after Tl injection, and the delayed washout rate (delayed WR) was determined at 240 min. From the duration of regional wall motion abnormalities on ESE, the patients were divided into Group A (wall motion abnormalities persisting for ?20 min, n=8) and Group B (<20 min, n=15). At each point of assessment, early WR was significantly lower in Group A than in the control group (5 healthy subjects) and Group B (p<0.01). In addition, the early WR at 20 min was negative in all Group A patients. The present study suggests that a persistent relative and reduction in myocardial blood flow is one factor responsible for prolonged abnormal regional wall motion. (author)

91

Diagnostic accuracy of supine and prone thallium-201 stress myocardial perfusion single-photon emission computed tomography to detect coronary artery disease in inferior wall of left ventricle  

International Nuclear Information System (INIS)

Prone thallium-201 (201Tl) myocardial perfusion single-photon emission computed tomography (SPECT) reduces false-positive rates when evaluating inferior wall abnormalities by minimizing diaphragmatic attenuation. The present study investigates the diagnostic validity of prone 201Tl stress myocardial perfusion SPECT for detecting coronary artery disease in the inferior wall of the left ventricle in Japanese patients. Of the 104 consecutive patients who underwent 201Tl stress myocardial perfusion SPECT to diagnose coronary artery disease, we evaluated 46 who underwent image acquisition in both the supine and prone positions, and coronary angiography within 3 months thereafter. Images were acquired in the routine supine position immediately following 201Tl (111 MBq) injection and 4 h following early acquisition. Images were acquired in the prone position only during the early phase following supine acquisition. We evaluated the SPECT images of the inferior half segments of the left ventricle using a five-point defect scoring system. According to the coronary angiographic findings, we investigated the diagnostic accuracy of stress-rest supine, stress supine, stress prone, and combined supine-prone images. Reduced uptake in the stress supine image of the combined images was considered as attenuation when uptake was normal in the prone image. The sensitivity of the stress-rest supine, stress supine, stress prone, and stress-combinss supine, stress prone, and stress-combined supine-prone images was 77%, 86%, 55%, and 55%, and the specificity was 71%, 54%, 79%, and 83%, respectively. Diagnostic accuracy was the highest in stress-rest supine images. Prone images tended to improve the specificity of detecting coronary artery disease in the inferior wall, but not diagnostic accuracy compared with stress-rest supine images because of decreased sensitivity. (author)

92

Diagnosis of ischemic lesion by {sup 201}Tl myocardial three-dimensional polar map. Comparison between before and after administration of Amlodipine  

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In order to apply the three-dimensional polar map using the Application Visualization System-Medical viewer (AVS-MV) in clinical cases, we have conducted the {sup 201}Tl myocardial SPECT studies before and after the pharmacotherapy of Amlodipine to thirteen cases with old myocardial infarction. We have visually evaluated the three-dimensional polar maps, and the improvement of the myocardial perfusion of infarct area was observed after administration of Amlodipine in nine out of thirteen cases (69%). Significant improvements of severity score in the entire area of left ventricle were indicated on stress images and delayed images (p<0.05). Significant improvements were also demonstrated in the %Tl uptake and washout rate of infarct areas (p<0.05). With the administration of Amlodipine, improvement of myocardial perfusion was indicated on the exercise stress test. With the use of AVS-MV, the three-dimensional polar map was easy to operate and improved form of myocardial perfusion was observed in the infarct area before and after the administration of Amlodipine on three-dimensional image, although we used the myocardial phantom as the basic image. (author)

Yamazaki, Junichi; Muto, Hiroshi; Ishida, Shuichi; Uno, Nariaki; Saisho, Kenichiro; Morishita, Takeshi [Toho Univ., Tokyo (Japan). School of Medicine

1996-11-01

93

Diagnosis of ischemic lesion by 201Tl myocardial three-dimensional polar map. Comparison between before and after administration of Amlodipine  

International Nuclear Information System (INIS)

In order to apply the three-dimensional polar map using the Application Visualization System-Medical viewer (AVS-MV) in clinical cases, we have conducted the 201Tl myocardial SPECT studies before and after the pharmacotherapy of Amlodipine to thirteen cases with old myocardial infarction. We have visually evaluated the three-dimensional polar maps, and the improvement of the myocardial perfusion of infarct area was observed after administration of Amlodipine in nine out of thirteen cases (69%). Significant improvements of severity score in the entire area of left ventricle were indicated on stress images and delayed images (p<0.05). Significant improvements were also demonstrated in the %Tl uptake and washout rate of infarct areas (p<0.05). With the administration of Amlodipine, improvement of myocardial perfusion was indicated on the exercise stress test. With the use of AVS-MV, the three-dimensional polar map was easy to operate and improved form of myocardial perfusion was observed in the infarct area before and after the administration of Amlodipine on three-dimensional image, although we used the myocardial phantom as the basic image. (author)

94

Evaluation of mandibular invasion by head and neck cancers using 99mTc-methylene diphosphonate or 99mTc-hydroxymethylene diphosphonate and 201Tl chloride dual isotope single photon emission computed tomography  

International Nuclear Information System (INIS)

Whether a patient with head and neck cancer has mandibular invasion or not is important in determining the method of resection surgery. But, no modality is adequately reliable when used alone in the evaluation of mandibular invasion. Therefore, to more accurately diagnose mandibular invasion in head and neck cancer, we used a new modality, namely, 99mTc methylene diphosphonate (MDP) or 99mTc hydroxymethylene diphosphonate (HMDP) and 201Tl chloride dual isotope single photon emission computed tomography (Tc/Tl SPECT). The aim of this study is to disclose the usefulness of Tc/Tl SPECT in the assessment of mandibular invasion by head and neck cancers. 99mTc-MDP or -HMDP SPECT (Tc SPECT)s and 201Tl chloride SPECT (Tl SPECT)s were performed in 34 patients with suspected mandibular involvement of head and neck cancer. Thirty of 34 cases underwent both Tc/Tl SPECT and CT examination. Tc/Tl SPECT fusion images were obtained using the Automatic Registration Tool (ART, TOSHIBA, Japan) system. In the diagnosis of mandibular invasion on Tc/Tl SPECT fusion images, a problem was that the range of Tc and Tl uptake was changed by the condition of display used in the reconstruction and expression of the images. Then, prior to clinical evaluation, to reveal the most appropriate upper window level for display, a phantom study was performed. In a clinical study, the upper window level was set at 40 or 50%, which were verified to be t at 40 or 50%, which were verified to be the proper values in the preliminary study. The diagnostic accuracy obtained using Tc SPECT, Tc/Tl SPECT and CT was compared with the histopathological findings. Tc/Tl SPECT at 40 and 50% upper window level had higher specificity, accuracy, and positive predictive value (73.3%, 85.3%, 81.8%) than Tc SPECT alone (21.4%, 67.6%, 64.5%) and higher sensitivity and negative predictive value (94.7%, 91.7%) than CT (70.6%, 72.2%) for detecting mandibular invasion. Tc/Tl SPECT was a useful diagnostic procedure for the assessment of mandibular invasion by head and neck cancers. (author)

95

201Tl myocardial scintigraphy and 13N-NH3 positron computed tomography in evaluating myocardial blood flow  

International Nuclear Information System (INIS)

We examined the ratio of myocardial uptake of Tl-201 to the total dose administered at rest and during exercise, in order to assess myocardial blood flow. The usual dose of Tl-201 (2 - 3 mCi) was diluted to 20 ml of normal saline and 15 ml were injected intravenously as a bolus. Subsequently the remaining 5 ml were injected in the same manner. Myocardial Tl-201 uptakes after the first dose were comparable to those of the second dose at rest when myocardial uptake immediately before the second injection was subtracted and multiplied by 3 (r = 0.98). This technique was applied during exercise to evaluate coronary reserve. Symptom-limited exercise was performed using a sitting ergometer and the first dose of Tl-201 was administered. After the routine scintigraphy with multiple views was completed, a second dose was given at rest. Myocardial uptake was greater during exercise than at rest by 32.6 ± 15.1 % (mean ± SD) in 18 normal subjects. This was significantly greater than that of 20 patients with coronary artery disease (5.8 ± 15.3 %; p 13N-NH3 has some advantages for calculations. Percent myocardial uptake of 13N during exercise was practically equal to that at rest in six normal subjects (97.1 ± 25.0 %), but it was slightly reduced in patients with coronary artery disease (90.1 ± 18.2 %). This reduction in cases of cor.2 %). This reduction in cases of coronary artery disease was significant only when evaluated for ischemic segments (65.4 ± 11.7 %; p 13N activity in the ischemic areas. The assessment of Tl-201 myocardial uptake using a new two-sequential administration technique is easy and valuable for the evaluation of myocardial ischemia. Positron scintigraphy with 13N-NH3 is potentially more accurate in evaluating myocardial perfusion. (J.P.N.)

96

Clinical significance of diffuse slow washout pattern (DSWO) on the exercise stress 201Tl SPECT myocardial imaging: Correlative study with influencing factors  

International Nuclear Information System (INIS)

DSWO shown on the Bull's eye images was found in 98 of 1234 patients suspected of having coronary artery disease and examined with 201Tl myocardial SPECT imaging. 48 of these 98 patients underwent coronary arteriography. Comparison studies were performed between Bull's eye SPECT image, coronary arteriography and laboratory data. DSWO was found in 11 cases with single vessel disease (1VD), 18 cases with double vessel disease (2VD) and 21 cases with triple vessel disease (3VD). Three of 58 cases with stenosis of a cardiomyopathy. In the CAD group, DSWO appeared frequently accompanying hypertension, hyperlipemia and diabetes mellitus. These complications tended to increase in patients with 1VD and the stenosis less than 75%

97

Comparative study of dobutamine stress echocardiography and dual single-photon emission computed tomography (Thallium-201 and I-123 BMIPP) for assessing myocardial viability after acute myocardial infarction  

Energy Technology Data Exchange (ETDEWEB)

Discordance between the {sup 123}I-labelled 15-iodophenyl-3-R, S-methyl pentadecanoic acid (BMIPP) and {sup 201}Tl findings may indicate myocardial viability (MV). This study compared dobutamine stress echocardiography (DSE) and single-photon emission computed tomography (SPECT) using the dual tracers for assessment of MV and prediction of functional recovery after acute myocardial infarction (AMI). DSE and dual SPECT were studied in 35 patients after AMI, of whom 28 underwent percutaneous coronary intervention in the acute stage. Dual SPECT was performed to compare the defect score of BMIPP and {sup 201}Tl. The left ventricular wall motion score (WMS) was estimated during DSE and 6 months later to assess functional recovery of the infarct area. The rate of agreement of MV between dual SPECT and DSE was 89% (p<0.01), and the sensitivity and specificity of DSE for dual SPECT in MV assessment was 86% and 93%, respectively. The positive and negative predictive values for functional recovery by dual SPECT were 76% and 67%, respectively, and by DSE were 90% and 79%, respectively. Four of 5 patients with positive MV by dual SPECT, but without functional recovery, had residual stenosis of the infarct-related artery. The WMS and defect scores of BMIPP and {sup 201}Tl were significantly smaller in patients with functional recovery than in those without. Assessment of MV using DSE concords with the results of dual SPECT in the early stage of AMI. DSE may have a higher predictive value for long-term functional recovery at the infarct area. However, a finding of positive MV by dual SPECT, without functional recovery, may indicate residual stenosis of the infarct-related artery, although the number of cases was small. Combined assessment by dual SPECT and DSE may be useful for detecting MV and jeopardized myocardium. Furthermore, the results suggest that functional recovery of dysfunctional myocardium may depend on the size of the infarct and risk area. (author)

Yasugi, Naoko; Hiroki, Tadayuki [Fukuoka Univ., Chikushino (Japan). Chikushi Hospital; Koyanagi, Samon [National Fukuoka-Higashi Hospital, Koga (Japan). Clinical Research Inst.; Ohzono, Keizaburo; Sakai, Kikuo; Matsumoto, Takahiro; Sako, Shigeki; Homma, Tomoki; Azakami, Shirou [National Kyushu Medical Center, Fukuoka (Japan)

2002-12-01

98

Comparative study of dobutamine stress echocardiography and dual single-photon emission computed tomography (Thallium-201 and I-123 BMIPP) for assessing myocardial viability after acute myocardial infarction  

International Nuclear Information System (INIS)

Discordance between the 123I-labelled 15-iodophenyl-3-R, S-methyl pentadecanoic acid (BMIPP) and 201Tl findings may indicate myocardial viability (MV). This study compared dobutamine stress echocardiography (DSE) and single-photon emission computed tomography (SPECT) using the dual tracers for assessment of MV and prediction of functional recovery after acute myocardial infarction (AMI). DSE and dual SPECT were studied in 35 patients after AMI, of whom 28 underwent percutaneous coronary intervention in the acute stage. Dual SPECT was performed to compare the defect score of BMIPP and 201Tl. The left ventricular wall motion score (WMS) was estimated during DSE and 6 months later to assess functional recovery of the infarct area. The rate of agreement of MV between dual SPECT and DSE was 89% (p201Tl were significantly smaller in patients with functional recovery than in those without. Assessment of MV using DSE concords with the results of dual SPECT in the early stage of AMI. DSE may havECT in the early stage of AMI. DSE may have a higher predictive value for long-term functional recovery at the infarct area. However, a finding of positive MV by dual SPECT, without functional recovery, may indicate residual stenosis of the infarct-related artery, although the number of cases was small. Combined assessment by dual SPECT and DSE may be useful for detecting MV and jeopardized myocardium. Furthermore, the results suggest that functional recovery of dysfunctional myocardium may depend on the size of the infarct and risk area. (author)

99

Assessment of diastolic function using 16-frame 201Tl gated myocardial perfusion SPECT. A comparative study of QGS2 and pFAST2  

International Nuclear Information System (INIS)

The objective of the present study is to investigate the correlations across various types of interface software for 201Tl gated myocardial perfusion SPECT (MPS) in calculating two common diastolic function parameters (DFx), peak-filling rates (PFR), and time-to-peak filling (TTPF). A total of 109 patients (66 men and 43 women; age 35-78 years) were studied. All patients were classified into three groups (i.e., ND, no-defect group; SD, small-defect group; LD, large-defect group) to clarify the influence of perfusion defects possibly affecting the analysis. Two kinds of available software, namely, quantitative gated SPECT (QGS2) and perfusion and functional analysis for gated SPECT (pFAST2) with cardioGRAF were used to obtain PFR and TTPF. Finally, we analyzed the correlation between DFx obtained with the two different kinds of software. The values of left ventricular diastolic function (LVEF), PFR, and TTPF were assessed in all patients. In both the ND (correlation coefficients were 0.92, 0.79, and 0.99, respectively) and SD groups (correlation coefficients were 0.74, 0.88, and 0.98, respectively), a strong correlation was observed. In contrast, PFR did not show a significant correlation in the LD group. With the two different kinds of software, QGS2 and pFAST2, the calculated PER was almost equal and showed good correlations in both ND and SD groups. In contrast, the numerical value varied between the two methods, and its correlation was poor in the LD groand its correlation was poor in the LD group. However, TTPF showed a good correlation regardless of the presence of perfusion defects, and the values were equal. TTPF was confirmed to be a stable diastolic index across the two kinds of software, QGS2 and pFAST2, in 201Tl gated MPS. (author)

100

Acute and reperfused myocardial infarction: relations between 'reverse redistribution' of 201Tl at rest, micro-perfusion and myocardial viability  

International Nuclear Information System (INIS)

The mechanism of 'reverse redistribution' (RR) of thallium after myocardial infarction remains obscure. In fact, the fixation of thallium depends on the coronary flow rate, microcirculation and cellular viability. We have studied the RR in 18 patients with normal coronary flow rate after reperfusion of artery of acute phase infarction but with a large range of micro-circulation alteration (evaluated by intracoronary contrast echography (ICCE)) and necrosis size. A thallium rest-redistribution achieved at the eighth day (8D) and 42D was compared with a perfusion score established by ICCE and analyses of the echographic regional kinetics achieved at 0D, 8D and 42D. At 8D a RR was observed in 16/18 patients with a 15 minute average defect of 25 ± 15% of myocardium extended up to 34 ± 13% at 4 hours. At 42D only 6/18 patients retained a RR while the average changes in the size of defect were not significant. The defect measured at 8D on the 15 min. image alone showed to be significantly correlated with the perfusion score while the patients with bad micro-perfusion had defects significantly larger than the others. On the other side the size of the same defect at 15 min. showed to be correlated to that of redistribution at 42D as well as the number of the akinetic segments at 42D. In conclusion, a large a RR is present at 8D after acute reperfusion of a myocardial infarction and tends to vanish at 42D. The 15 minute images reflect essentially the micro-perfusion. The lasessentially the micro-perfusion. The last one being a necessary condition of myocardial salvation, the size of the 15 minute defect is also correlated to the viability indices evaluated at 42D

 
 
 
 
101

Clinical significance of 201Tl lung uptake in heart disease  

International Nuclear Information System (INIS)

In order to evaluate the clinical significance of 201Tl lung uptake, 201Tl myocardial scintigraphy was performed in 675 cases with various cardiac diseases. The lung uptake ratio of 201Tl (L/T) was calculated by ratio of the total radioactivity of the unilateral lung to the injected dose of 201Tl in 69 cases. Using both 201Tl scintigraphy and cardiac pool scintigraphy with 99mTc-human serum albumin, images of 201Tl of the intravascular space and extravascular space were obtained in 14 cases. The image of 201Tl of the extravascular space was almost the same as the original 201Tl image as regards the pattern of 201Tl-distribution, and the lung uptake ratio of the former was 95.7 ± 2.8% of that of the latter. The mean values of L/T of the right and left lungs were 1.5 ± 0.9%, 1.2 ± 0.6% in the healthy lungs, 2.8 ± 1.4% and 1.4 ± 0.7% in heart diseases without left heart failure, and 4.4 ± 1.8% and 2.6 ± 1.2% in those with left heart failure, respectively. Increased lung uptake ratio of 201Tl, which was related to post-capillary pulmonary hypertension, prolonged pulmonary circulation time and findings of left heart failure, was observed more frequently in mitral valvular diseases (72.2%) and dilated cardiomyopathies (60.0%). Increased lung uptake of 201Tl was associated with normal or increased pulmonary perfusion in many cases or areaary perfusion in many cases or areas, but with pulmonary hypoperfusion in some cases with post-capillary pulmonary hypertension, in whom both increased lung uptake of 201Tl and pulmonary hypoperfusion were shown in the lower lung fields. In conclusion, increased lung uptake of 201Tl suggests increased pulmonary extravascular space and calculation of the lung uptake ratio of 201Tl seems to be useful for the evaluation of left ventricular dysfunction. (author)

102

Quality control 201TlCl solution obtained at IPEN-CNEN/SP through the direct method of 201Tl preparation  

International Nuclear Information System (INIS)

The radiopharmaceutical 201TlCl is used in Nuclear medicine for myocardial visualization. The solution of 201TlCl was prepared using 201Tl obtained by irradiating a natural mercury target with protons. This radionuclide was subjected to different quality control processes to verify the purity required for its use in Medicine. Some of these controls concerned the determination of 200Tl, 201Tl and 202Tl; the chemical identification of 201Tl+1; the hydrazine concentration, mercury contamination and the presence of phosphate. Furthermore, the biologic distribution in Wistar rats and tests for sterility, pyrogens and for toxicity were carried out. It was verified that the solution obtained was in the form of thallous chloride. This radiopharmaceutical can give a good heart image in animals but due to the contamination of 201Tl with 200Tl and 202Tl its use in human beings is not possible unless enriched 202Hg is used as target of irradiation. (author)

103

201Tl-myocardial scintigraphy: Current status in coronary artery disease, results of sensitivity/specificity in 3092 patients and clinical recommendations  

International Nuclear Information System (INIS)

This review is concerned with qualitative and quantitative sectorial 201Tl-redistribution analysis of exercise myocardial scintigraphy (EMS). In 3092 cases the sensitivity (specificity) was on average 83(90)%, the average CAD prevalence scintigraphy (EMS). In 3092 cases the sensitivity (specificity) was in average 83(90)%, the average CAD prevalence being 71%. Sensitivity (Se) for EMS (ExECG) increased from 73(43)% in single vessel disease through 83(69)% in double vessel to 90(77)% in triple disease (n = 879); average Se was 77% for LAD-, 79% for RCA- and 65% for LCX-stenosis. Se for detection of the real extension of CAD conversely decreased from 59% in SVD through 41% in DVD down to 33% in TVD. Clinical recommendations for EMS and rest scans are outlined in CAD (atypical angina, follow-up after bypass-surgery, percutaneous transluminal angioplasty), in non-coronary artery diseae (non-ischemic cardiomyopathies, right ventricular hypertrophy) and in pediatric cardiology. (orig.)

104

ECG-gated dual-isotope myocardial SPECT with {sup 201}Tl and {sup 99m}Tc-tetrofosmin. Simultaneous assessment of stress/rest myocardial perfusion and left ventricular function  

Energy Technology Data Exchange (ETDEWEB)

ECG-gated dual-isotope acquisition protocol involving rest imaging with {sup 201}Tl and stress {sup 99m}Tc-tetrofosmin (TF) SPECT was designed for the simultaneous assessment of rest/stress myocardial perfusion and rest ventricular systolic function. This study assessed the feasibility and diagnostic accuracy of this protocol. Forty-five patients underwent the dual-isotope SPECT protocol. Twenty minutes after resting injection of 111 MBq {sup 201}Tl, 370 MBq of {sup 99m}Tc-TF was administered at a peak exercise. The dual-isotope gated SPECT acquisition was performed 1 hour later. Then, the regional count increase rate (%WT) of {sup 99m}Tc-TF from end-diastole to end-systole was calculated using an automated method which was developed for quantification of regional wall thickening based on circumferential profile analysis in our laboratory. Myocardial perfusion and contractility analysis was carried out using 8 segments of left ventricle with comparison of coronary angiographical findings. The sensitivity and specificity for the detection of diseased coronary vessels ({>=}75% stenosis) were 76% and 94%, respectively. Infarcted regions showing reversible defect had significantly greater %WT as compared with those with fixed defects (63 seg; 12.7{+-}6.1% vs. 36 seg; 8.9{+-}7.2%, p<0.01). In conclusion, this dual-isotope protocol has some advantages; i.e., shortening an examination time, having the exact registration of stress/rest perfusion, and simultaneous evaluation of resting regional wall thickening. (author)

Kumita, Shin-ichiro; Cho, Keiichi; Mizumura, Sunao [Nippon Medical School, Tokyo (Japan)] [and others

1996-11-01

105

Coronary spasm: 201Tl scintiscanning following pharmacological provocation  

International Nuclear Information System (INIS)

According to the authors' experience so far, 201Tl myocardial scintiscanning is a sufficiently sensitive non-invasive method for detection of coronary vasospasm provoked by ergotamine administration. Mild incomplete and asymptotic forms of coronary vasospasm were detected by scintiscanning. Indications for myocardial scintiscanning of ergotamine-provoked vasospasm are: Cases of angina pectoris at rest in which electrocardiograms during spasm are not available; elleviated symptoms after nitroglycerine administration; exercise electrocardiograms without any sign of ischaemia; negative results of exercise 201Tl myocardial scintiscanning. (orig.)

106

Measurement of myocardial perfusion and metabolic viability with 18 F-FDG, 201 TL and 99m Tc MIBI using a normal gamma camera: results of routine examination of 60 patients  

International Nuclear Information System (INIS)

18F-Fluoro-Deoxy-Glucose (18F-FDG) is known to be taken up in ischemic myocardium (MC), even in persistent perfusion defects with 201 Thallium (201 Tl), as in hibernating or stunned MC. It is shown how experiences with Positron Emission Tomography (PET) imaging can be reproduced with a modified Anger-type Camera, the most common Nuclear Medicine tool shielded with a lead reinforced table and fitted with special lead protected Seven PinHole (SPH) Collimator. Routinely static SPH images with 99m Tc-Cardiolite were compared with 18F-FDG images which have been obtained during the same session and in identical position in pts up to 12 weeks after acute Myocardial Infarction (MI). 201 Tl stress/redistribution studies had shown scars in all, confirmed by X-ray coronaro/angiography, and 99mTc-first-pass-angiography. More than half of these scars showed FDG uptake in the lesions. It is concluded that SPH-Tomoscintigraphy with 201 Tl, 99m Tc-Cardiolite and 18F-FDG is a widely available method for the detection of ischemic but viable myocardium after MI. This technique can be used much easier than PET in daily practice. 18F-FDG exams could be made available within 1 hour transportation distance from a cyclotron. 7 refs., 2 figs

107

Clinical evaluation of 123I-BMIPP myocardial SPECT in patients with hypertensive heart disease and hypertrophic cardiomyopathy. Comparison with the findings of 201Tl SPECT and Gd enhanced magnetic resonance imaging  

International Nuclear Information System (INIS)

123I-BMIPP SPECT (123I-BMIPP), 201Tl SPECT (201Tl), and Gd-DTPA enhanced magnetic resonance myocardial imaging (MR) were performed in patient groups with hypertensive heart disease (HHD), apical hypertrophic cardiomyopathy (APH), and hypertrophic cardiomyopathy without APH (HCM). SPECT was divided into 20 segments and each segment was scored as one of 4 grades (0=normal; 1=mildly decreased; 2=severely decreased; and 3=defect) according to the RI uptake. Gd enhancement in MR was interpreted visually. A decreased in the uptake of 123I-BMIPP showed in 54 of 141 hypertrophic (>13 mm, measured by ultrasonic cardiography) segments in HHD, in 32 of 66 in APH and in 103 of 207 in HCM respectively. Whereas 201Tl SPECT showed decreased uptake in 18 of 141 hypertrophic segments, in 18 of 66 in APH, and in 27 of 207 in HCM, respectively 123I-BMIPP showed a higher incidence of these scintigraphic abnormalities than did 201Tl in the hypertrophic segments. And also in the hypertrophic segments, decreased in the uptake of 123I-BMIPP occurred more frequently in HCM than in HHD. In HCM, decreased 123I-BMIPP uptake appeared more frequently in segments 1, 2, 9, and 10 (antero-septal junction) than in other segments, but in APH, such decreases occurred more often in segments 17, 18, 19, and 20 (apex). Enhanced signal intensity with Gd-DTPA appeared in more segments in the HCM grou appeared in more segments in the HCM group than in the APH or HHD groups. We concluded that HCM had the most extensive and severe structural changes-including metabolic and ischemic changes-among three groups, and that the combination of these three examinations was useful for evaluating the characteristics of hypertrophic myocardium. (author)

108

Prediction of late recovery of left ventricular function with quantitative mismatch between 123I-BMIPP and 201TlCl myocardial SPECT imaging in acute phase of myocardial infarction  

International Nuclear Information System (INIS)

To quantitative calculation of myocardium fatty acid metabolism/myocardium blood flow, 123I-BMIPP and 201TlCl myocardium SPECT images were made from Bull's eye image. Mismatch area was sought from this image, and it's reference with amelioration of cardiac function 1 month after the examination. Thirty-two cases (male: 26, female: 6) of the first acute myocardial infarction, which received successfully reperfusion therapy within 12 hours after stroke, were enrolled. The average age was 64.2±7.9-year-old. Dual SPECT was performed for less than 2 weeks after stroke. SPECT was performed on 30 minutes after administration of 111 MBq of 123I-BMIPP. Just after, 74 MBq of 201TlCl was injected intravenously and SPECT was performed 10 minutes later. Each image of fatty acid metabolism/blood flow (mismatch ratio: MR) was obtained by subtraction of standardized from Bull's eye respectively. Mismatch volume (MV) was also calculated. Echocardiogram was enforced at admission and 1 month after, and difference of left ventricle ejection fraction (? LVEF) was calculated. Relation between MV and ? LVEF was recognized in case of slight mismatch of 0.85-0.95 at the intermediate degradation area (60-70%) of Tl accumulation (r=0.736, p<0.001). It became clear that cardiac function improved in chronic stage in cases of slight mismatch at the intermediate degradation area of Tl accumulation. (K.H.)

109

Ability of 201Tl and 123I-BMIPP mismatch to diagnose myocardial ischemia in patients with suspected coronary artery disease  

International Nuclear Information System (INIS)

A mismatch defect between 201TL and 123I-beta-methyliodophenylpentadecanoic acid (BMIPP) dual isotope SPECT (d-SPECT) is useful to detect myocardial ischemia in patients with acute coronary syndrome. However, whether mismatched d-SPECT findings reflect actual myocardial ischemia in stable patients with suspected, but unknown ischemic heart disease is unclear. The present study assesses the significance of a d-SPECT mismatch among such patients. Forty-nine patients with suspected stable coronary heart disease who had been referred for chest pain, electrocardiogram (ECG) abnormalities or multiple risk factors (66±11 years old, 34 males) with a d-SPECT mismatch participated in this study. All of them underwent coronary angiography (CAG) to assess coronary artery disease. The entire myocardial area on d-SPECT images was divided into 17 segments, each of which was scored from 0 (normal) to 4 (defect). The d-SPECT mismatch score (MS) was defined as the summed BMIPP defect score (BM-TDS) minus the summed defect score (TL-TDS). The inclusion criterion was MS?1, and the mismatch was defined as true positive if the mismatched area was concordant with the territories supplied by significant coronary stenotic arteries by CAG. Ischemic heart disease was judged by coronary angiography in 31 (63%) patients (IHD group), of which 24 (49.0%) were true positives. Of the remaining 18 (37%) patients without no significant coronary stenosis (non-IHD group), 12 (24%onary stenosis (non-IHD group), 12 (24%) had some types of organic heart disease. If MS?4 was defined as the threshold for an ischemic positive mismatch, then the sensitivity and specificity were 80% and 63%, respectively. However, mismatch scores did not significantly differ between the groups with true positive-IHD and organic heart disease in non-IHD group (6.6±4.4 vs. 6.4±3.7). A d-SPECT mismatch score of ?4 was an appropriate cutoff at which diagnosis of myocardial ischemia in patients who were screened for ischemic heart disease. However, since patients with non-ischemic but organic heart disease can also present with abnormal mismatch findings, coronary angiography or CT might be warranted to differentiate IHD from non-IHD. (author)

110

Incremental value of 24-hour delayed imaging in 201Tl stress myocardial perfusion studies (MPS) with an 'early rest reinjection' protocol  

International Nuclear Information System (INIS)

Full text: One hundred patients (pts) undergoing stress MPS had 24 h imaging for fixed defects at 4 h delayed imaging. 53 had prior myocardial infarction (MI) and 71 were males. Stress employed isotonic exercise with dipyridamole (0.56 mg kg-1) infusion in 57 pts, exercise alone in 33 and dipyridamole alone in 10. All pts with stress defects had rest-reinjection of 40 MBq of 201Tl after stress imaging had been completed, and most had sublingual nitrate therapy 10 min before reinjection. MPS from the 100 pts (15% of total) were read without clinical data, using a 20 segment scoring system. 51 pts showed -2 segments improvement between 4 and 24 h scores, but 22 pts had shown reversibility between stress and 4 h imaging and the further change did not alter interpretation. The other 29 pts (group A) showed clinically important change in 24 h scores, leaving 71 pts without clinical change (group B). Segmental improvement between 4 and 24 h in group A was 4.62 ± 2.18 and 1.18 ± 1.48 in group B (P = 0.02). Group A stress defect scores were not greater (10.90 ± 3.60) or more severe (3.72 ± 3.06) than in group B (8.92 ± 4.34 and 2.79 ± 3.11); 18 group A pts had MI compared with 38 group B pts. No significant correlation was found between improved 4-24 h scores and parameters of stress-LV dysfunction. There is benefit from 24 h, 201TI MPS in patients with persisting 4 h defects, despite early rest-reinjection and acute nitrate therapyction and acute nitrate therapy

111

Feasibility of assessing regional myocardial uptake of 18F-fluorodeoxyglucose using single photon emission computed tomography.  

Science.gov (United States)

Differentiation between viable myocardium and scar tissue in segments with abnormal contraction has important consequences in the clinical management of patients with coronary artery disease. Positron emission tomography (PET) can identify viable tissue using 18F-fluorodeoxyglucose (FDG). However, application of PET for daily routine is limited. In this study, FDG uptake was visualized with single photon emission computed tomography (SPECT) and compared with regional perfusion assessed with thallium-201 (201Tl) SPECT. The scintigraphic findings were related to regional wall motion determined with two-dimensional echocardiography. Patients (n = 9) with wall motion abnormalities underwent FDG SPECT and resting 201Tl SPECT. To control the metabolic status patients were studied with a hyperinsulinaemic euglycemic clamp during FDG SPECT. Analysis of reconstructed data was performed visually and semiquantitatively using circumferential profiles. High-quality images were obtained. Eight 201Tl defects showed concordantly decreased FDG uptake (metabolism-perfusion matches) indicating scarred tissue, whereas six regions of hypoperfusion demonstrated a relatively increased FDG uptake (mismatches), suggesting viable myocardium. Semiquantitative analysis confirmed visual findings. Mean 201Tl and FDG activities were not significantly different in matching defects. In mismatches the mean FDG activity was 81 +/- 11% vs 64 +/- 9% mean 201Tl activity (P echo revealed hypokinesia. Seven of eight regions with a matching defect in contrast were akinetic. Thus, in the areas with a mismatch contractility was preserved. We conclude that FDG uptake can be visualized with SPECT. Furthermore, our preliminary observations suggest that this approach can identify viable tissue. PMID:8131767

Bax, J J; Visser, F C; van Lingen, A; Huitink, J M; Kamp, O; van Leeuwen, G R; Visser, G W; Teule, G J; Visser, C A

1993-12-01

112

Synthesis and in vivo evaluation of 201Tl(III)-DOTA complexes for applications in SPECT imaging  

International Nuclear Information System (INIS)

Introduction: The aim of this study was to assess the use of 201thallium3+ (201Tl3+) as a radiolabel for nuclear imaging tracers. Methods for labeling of 1,4,7,10-tetraazacyclododecane-N,N',N'',N''' tetraacetic acid (DOTA) and diethylenetriaminepentaacetic acid (DTPA) chelators with 201Tl3+ were investigated, and the levels of stability of these chelates were tested in vitro and in vivo. Methods: 201Tl(I)Cl was treated with hydrochloric acid and ozone to form 201Tl(III)Cl3. The procedure for labeling of DOTA and DTPA was optimized, testing different buffer solutions and pH values. The stability levels of 201Tl(III)-DOTA and 201Tl(III)-DTPA were assessed in buffer, mouse serum and human serum (1:1, v/v) at a temperature of 310 K for 48 h. Subsequently, in vivo stability studies with 201Tl(III)-DOTA were performed, comparing the biodistribution of 201Tl(III)-DOTA with that of 201Tl(I)Cl in a single-isotope study and with that of 177Lu(III)-DOTA in a dual-isotope single photon emission computed tomography study. Results: 201Tl(III)-DTPA, 201Tl(III)-DOTA and 177Lu(III)-DOTA were prepared with >95% radiochemical purity. While 201Tl(III)-DOTA showed a prolonged level of stability in buffer and serum, 201Tl was quickly released from DTPA in serum. Apart from y released from DTPA in serum. Apart from some urinary excretion, the biodistribution of DOTA-chelated 201Tl3+ was similar to that of free (ionic) 201Tl+ and did not match the biodistribution of 177Lu(III)-DOTA. This indicated a limited stability of 201Tl(III)-DOTA complexes in vivo. Conclusion: Despite promising results on the labeling and in vitro stability of 201Tl(III)-DOTA, our in vivo results indicate that the integrity of 201Tl(III)-DOTA decreases to 201Tl3+ as a radiolabel for tracer imaging.

113

Thallous chloride-201Tl  

International Nuclear Information System (INIS)

Biological behavior of Tl-201 in rat and man was studied for evaluation of its myocardial imaging properties, and the MIRD method was used to calculate dose. Metabolites in urine of rats and patient and water soluble component of rat feces were chromatographically examined. Scintiphotographic images obtained from 30 patients were evaluated from the diagnostic point of view in comparison with the diagnosis obtained from ECG. In rat, organ uptakes were observed in gut, kidney and liver, with the highest radioactivity concentration being observed in the heart (myocardium). Blood clearance and clearance from the heart changed with time showing a similar pattern to each other, the concentration in the heart, however, was always higher than that of the blood. Within 72 hrs, 15% and 32% of administered dose were excreted in urine and feces, respectively. From the clinical data, a slower activity clearance was observed in the heart when compared to the right lung region. Half-life for blood clearance at the initial stage was calculated to be 1 to 2 min. A possibility of clear myocardial imaging for a considerably long time after injection was suggested from the results obtained by body surface counting and blood clearance. Fecal excretion was predominant and in 72 hrs, 14% of administered dose were excreted. Chromatographic examinations on excretions of rat and patient revealed that Tl-201 administered was excreted without any metabolic changes, such as oxidation to thallic iic changes, such as oxidation to thallic ion. Estimated exposure doses were different from that of reported values. This may be due to using longer biological half-life values based on the excretion data obtained from patients in our calculations. All the myocardial images were clear and useful for myocardial disease and the diagnostic results agreed well with those obtained from ECG. (auth.)

114

Spectroscopy of 201Tl isotope  

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Variation of the nuclear deformation as a function of angular momentum for chain of Tl isotopes makes them interesting candidates to test the predictions of different theoretical models involving the coupling of core and single particle degrees of freedom. Tl isotopes with one proton hole in Z = 82 shell and a few neutron hole in N = 126 shell are expected to have spherical structure at lower excitation while the deformation sets in for higher spin states. For odd A Tl isotopes ground state spin is ½, and the ?h9/2 orbital above the Z = 82 shell closure is accessible by the odd proton for oblate deformation. A rotational band build on 9/2- isomeric level have been reported for 195-199Tl isotopes. In case of 201Tl, a few members of the 9/2- rotational band have been observed from deuteron induced fusion reaction. Rotational band based on the intruder ?i13/2 orbital have been observed in some of the lighter odd-mass Tl nuclei and recently in 197Tl. The aim of the present work is to extend the band structures of 201Tl to higher spin states

115

A comparison between terminally radioiodinated hexadecenoic acid (sup(*)I-HA) and 201Tl-thallium chloride in the dog heart  

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The regional myocardial distribution of 131I-16-iodo-9-hexadecenoic acid (131I-HA) and 201Tl-thallium chloride (201TlCl) was determined in normal dogs and after occlusion of a coronary artery. The uptake of 131I-HA was about 20% lower than that of 201TlCl but the ratio 201Tl/131I was the same for the whole myocardium within narrow limit for normal as well as infarcted tissue. The potential of 123I-HA as a radiopharmaceutical for diagnosis of myocardial defects is discussed. (orig.)

116

Diagnosis of coronary artery disease with 201Tl  

International Nuclear Information System (INIS)

The diagnostic sensitivity of visually interpreted and computer-analyzed 201Tl myocardial perfusion images was compared to that of exercise electrocardiograms in 8 angiographically normal subjects and 24 patients with significant coronary artery disease. Visual interpretation was not significantly better than exercise ECGs. An index of perfusion homogeneity, derived from computer analysis of the 201Tl images, was more sensitive than visual interpretation (79 percent vs. 58 percent) and much more sensitive (p less than 0.05) than the exercise ECG (79 percent vs. 46 percent). The best overall sensitivity (88 percent) and specificity (75 percent) were achieved by combining computer analysis with exercise electrocardiography. The computer also permits enhanced detection of subtle perfusion changes which may not seem significant to the eye

117

Thallium-201 single photon emission computed tomography in patients with symptoms of heart disease and non-significant coronary artery lesions  

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Polar presentations of coronary angiograms and myocardial 201Tl SPECT were compared in 44 patients without significant coronary artery disease (201Tl SPECT overlap but are not congruent. Coronary angiography describes morphology of large coronary vessels, whereas 201Tl SPECT contains information of large and small vessel perfusion as well as membrane transport of 201Tl ions. (orig.)

118

Phantom evaluation of scatter and attenuation correction in thallium-201/technetium-99m acquisition in myocardial perfusion single-photon emission computed tomography  

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This phantom study was carried out to evaluate the usefulness of scatter correction combined with transmission-based attenuation correction in separate and simultaneous {sup 201}Tl/{sup 99m}Tc myocardial SPECT. An anthropomorphic torso phantom was used in this study. We used the triple-energy-window (TEW) method for scatter correction and transmission computed tomography (TCT) images for attenuation correction. Images without corrections (UC) and images with corrections (SAC) for scatter and attenuation were reconstructed for the evaluation. The differences in defect size between {sup 99m}Tc and {sup 201}Tl UC images led to interpretation errors in separate (separate protocol) and simultaneous dual-isotope studies (simultaneous protocol). These errors were more prominent in the infero-posterior wall in the simultaneous protocol. Improvement for overestimation in object size and underestimation in defect contrast was visually obtained, and increased contrast was also shown by the myocardium-to-defect count (MD) ratios on SAC images in the separate and simultaneous protocols. However, {sup 201}Tl SAC images in the simultaneous protocol still had less defect contrast than the corresponding {sup 201}Tl SAC images in the separate protocol. From the results of our phantom experiment, separate rest {sup 201}Tl/ stress {sup 99m}Tc-sestamibi acquisitions may be recommended in clinical practice. Further clinical and phantom studies will be needed to validate the method using scatter correction combined with transmission-based attenuation correction. (author)

Ohyama, Yoichi; Tomiguchi, Seiji; Kira, Tomohiro; Kojima, Akihiro; Matsumoto, Masanori; Nishi, Jyunko; Katsuda, Noboru; Takahashi, Mutsumasa [Kumamoto Univ. (Japan). School of Medicine; Motomura, Nobutoku

2001-04-01

119

Efficacy of iodine-123-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid single photon emission computed tomography imaging in detecting myocardial ischemia in children with Kawasaki disease  

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To evaluate its efficacy in detecting myocardial ischemia in children, iodine-123-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) imaging was performed in 16 pediatric patients with Kawasaki disease (KD, 11 male, 5 female; mean age and range: 13 years 8 months and 8 years 11 months to 17 years 7 months). Five children with chest pain and no cardiac disease were studied as controls (2 male, 3 female; mean age and range: 13 years 4 months and 9 years 4 months to 17 years 11 months). Selective coronary angiography was also performed in the 16 patients to evaluate the location of coronary stenosis and coronary aneurysms. The SPECT images were expressed as polar maps (Bull's eye maps) and the 'defect' area was defined as where the uptake of BMIPP was less than the standardized BMIPP images of the 5 control children. In the 16 patients, 33 segments had coronary aneurysms and 10 (10/33: 30.3%) had significant coronary stenosis on selective coronary angiography. Nine of the 10 (90%) segments with significant coronary stenosis showed a defect on the BMIPP image whereas only 6 of the 23 (26.1%) segments without coronary stenosis showed a defect on BMIPP imaging. The sensitivity of BMIPP SPECT imaging for detection of coronary stenosis was 90% (9/10) and its specificity was 73.9% (17/23), whereas the sensitivity of 201Tl SPECT imaging was 80% (8/10) and its specificity was 60% (14/23). Ther and its specificity was 60% (14/23). There was no significant difference between the BMIPP and 201Tl SPECT images in either the sensitivity or specificity for the detection of coronary stenosis. In the present series, only one case had discordant BMIPP uptake (BMIPP uptake201Tl uptake) in which there was a large coronary aneurysm and re-canalization after complete obstruction at segment 1 of the right coronary artery. This discordant BMIPP uptake reflects the possibility of ischemic but viable myocardium after re-canalization of a large aneurysm in KD. In conclusion, BMIPP SPECT imaging is useful for detecting the areas of ischemic myocardium caused by coronary artery stenosis in children with KD. (author)

120

Thyroid scanning with 201Tl-chloride  

International Nuclear Information System (INIS)

Thyroid scanning with 201Tl-chloride was performed on 32 cases of thyroid pathology, comparing with that with sup(99m)Tc, 3 cases of follicular adenocarcinoma, 10 cases of papillary adenocarcinoma, 2 cases of mixed type of follicular and papillary adenocarcinoma, a case of poorly differentiated squamous carcinoma, a case of Huerthle cell carcinoma, 8 cases of follicular adenoma, 5 cases of chronic thyroiditis, a case of subacute thyroiditis and a case of Basedow's disease. The most important evidence of thyroid scanning with 201Tl-chloride is the hot nodule in primary malignant tumor and also metastasis in the mediastinal area. (auth.)

 
 
 
 
121

Quantitative analysis of myocardial tracer distribution in patients with ischemic heart disease. Comparison of 201Tl and 123I-15-(p-iodophenyl)-3-methylpentadecanoic acid (BMIPP)  

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Quantitative assessment of myocardial tracer uptake in stress-delayed thallium and resting BMIPP imaging was performed in 24 patients with coronary artery disease. Each distribution was displayed on the bull's eye polar map and % uptake of each distribution was calculated as a mean value in 9 myocardial segments on the polar map. Redistribution index (% delayed uptake minus % stress uptake on thallium images) and discordance index (% delayed thallium uptake minus % BMIPP uptake) were also calculated. Each parameter was compared to the visual uptake score and wall motion score on contrast left ventriculography. Excellent correlations were obtained between % uptake and the uptake score in each tracer. The % thallium and BMIPP uptake also correlated with regional wall motion score. Furthermore, a significant correlation was observed between redistribution and discordance indexes in the mildly hypoperfused segments. These data indicate that the quantitative analysis of thallium and BMIPP distributions seems to be valuable to understand relationship between perfusion and regional wall motion. The discordant BMIPP uptake may represent asynergic but viable segments. However, several important factors, such as attenuation factor should be also taken into consideration for such quantitative analysis. (author)

122

Detection of the viable myocardium. A perfusion scintigraphic study, before and after coronary bypass surgery in myocardial infarction patients  

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Full Text Available OBJECTIVE: To compare single-photon-emission computed tomography (SPECT imaging scans using 201Tl and 99mTc-MIBI in detection of viable myocardium, in regions compromised by infarction. METHODS: Thirty-two (59.3±9.8 years old and 87% male myocardial infarction patients were studied. All had Q waves on the ECG and left ventricle ejection fraction of <50%. They underwent coronary and left ventricle angiographies and SPECT before (including 201Tl reinjection and after coronary artery bypass surgery (CABG. Improvement in perfusion observed after surgery was considered the gold standard for myocardial viability. RESULTS: Among 102 studied regions of the heart, there were 40 (39.2% areas of transient perfusion defects in the conventional protocol with 201Tl and 52 (51.0% after reinjection. Therefore, 12/62 (19.4% more viable regions were identified by reinjection. Using 99mTc-MIBI, only 14 (13.7% regions with transient defects were identified, all of which were seen also in 201Tl protocols. After surgery, 49 of a total of 93 regions analyzed (52.7% were viable. Sensitivity, specificity, accuracy, positive and negative prediction values were, respectively, 201Tl SPECT scans - 65.3%, 90.9%, 77.4%, 88.9% and 70.2%, reinjection protocol with 201Tl scans - 81.6%, 81.8%, 81.7%, 83.3% and 80.0%; 99mTc-MIBI SPECT scans - 20.4%, 90.9%, 53.8%, 71.4% and 50.6%. Logistic regression demonstrated that the reinjection protocol with 201Tl was the best predictor of viability (P<0.001. CONCLUSION: Our data suggest the election of 201Tl for viability studies, especially when using the reinjection protocol.

Chalela Willliam A.

1999-01-01

123

Computer-aided diagnosis in two-phase 201Tl-SPECT of thoracic lesions  

International Nuclear Information System (INIS)

Aim: the retention index, a traditionally quantitative analysis of two-phase 201Tl single photon emission computed tomography (SPECT) of the chest, is manually calculated by experienced physicians from comparable 2-D ROI. However, a 3-D ROI would provide more information than a 2-D ROI extracted from a single frame of SPECT. We propose a new diagnostic system, computer-aided diagnosis (CAD), to automatically detect suspicious lesions as 3-D objects on chest 201Tl-SPECT, and assist the physician in interpreting these images. Patients, methods: seventy patients with thoracic lesions and confirmed diagnoses were enrolled to test this automatic CAD system. The reliability of the CAD system in detecting lesions as 3-D objects was compared to the 2-D ROI of 201Tl-SPECT found by the manually visualized method. Furthermore, we also proposed a novel index, the retention index using the heart (RIH), to differentiate high retention (slow clearance, increasing target to heart ratio) as a criterion for a malignant lesion, from low retention (faster clearance, small or no increase of the target to heart ratio) for benign lesions. Results: the CAD system can achieve a detection rate of 100% in automatically searching for thoracic lesions in 201Tl-SPECT. In diagnostic performance, the CAD system with the RIH of comparable 3-D objects has an area under the ROC curve of 0.86, higher than the 0.78 of the traditional RI method (p = 0.198). Conche traditional RI method (p = 0.198). Conclusion: the CAD system of two-phase 201Tl-SPECT is a promising tool for detecting and diagnosing thoracic lesions with a diagnostic accuracy of 0.81. (orig.)

124

Background subtraction in 201Tl myocardscintigraphy  

International Nuclear Information System (INIS)

Myocardscintigraphy with 201Tl produces images with rather high tissue activity (myocard/tissue = 2:1 at rest). To improve interpretation of the scintigrams, background corrections are applied. A method is described which calculates a background matrix, in which the anatomy of the patient is taken into consideration. For instance, there are no tissues in the area of the heart which contain background activity and the corrections here are therefore smaller than elsewhere. (C.F.)

125

Clinical evaluation of single-photon emission computed tomography for Tl-201 myocardial imaging  

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Single-photon emission computed tomography (SPECT) for Tl-201 myocardial imaging using a rotating gamma camera was evaluated for clinical diagnostic efficacy of myocardial infarction. Thirty-three cases with prior myocardial infarction and 28 cases without myocardial infarction were injected with 2 - 4 mCi of Tl-201 at rest. Planar imaging was performed for 5 views (ANT, LAO-30, 45, 60, L-LAT) and followed by SPECT. Overall time of the studies was within one hour. Results were as follows: (1) Sensitivity, specificity and overall accuracy for myocardial infarction diagnosis of SPECT system showed 96.9%, 78.6% and 88.5% respectively. In comparison with planar imaging, SPECT significantly improved sensitivity, however decreased specificity and slightly improved accuracy. (2) Overall interpretation of transaxial, coronal and sagittal images were required for the detection of myocardial infarction. (3) SPECT images showed more clearly findings of infarction than planar imaging and extension of myocardial infarction on SPECT images showed relatively well correlation with ECG diagnosis. (author)

126

Indications for single-photon emission computerized tomography in cardiology  

International Nuclear Information System (INIS)

The tomographic distribution of 201Tl in the myocardium was studied with a gamma camera with 2 detectors (29 cms in diameter) with 37 photo multipliers each. 201Tl-citrate in a dose of about 74 MBq was used in normal subjects, patients with coronary artery disease and with cardiac hypertrophy. Tomograp hic sections were obtained every 1.2 cms in the sagittal and frontal projections. The distribution of 201Tl was uniform in normal and hypertrophic hearts. Single-photon emission computerized tomography was instrumental in determining the extension of the damage of the myocardium to areas which appeared normal in the regular scintigrams

127

Visualization of myocardial perfusion defects in single photon emission computerized (SPECT) studies  

Science.gov (United States)

In this paper, we present a semi-automatic technique to quantize and to visualize myocardial perfusion defects volumetrically. This involves: (1) differentiating the myocardium from encroaching viscera, (2) determining the mass of myocardium, (3) locating and measuring the perfusion defects, and (4) graphically rendering them. First, to differentiate between myocardium and other thoracic structures, we introduce the concept of Maximum Intensity Surface Segmentation (MISS). By locating local maximums in our cardiac Single Photon Emission Computerized Tomography (SPECT) image and connecting ones sufficiently close together, we generate the basic shape of the myocardium and the encroaching ones sufficiently close together, we generate the basic shape of the myocardium and the encroaching structures. Second, with the shape of the myocardium determined, we then measure the thickness at each point of the heart wall. Fitting bicubic splines to the measured myocardial thicknesses, we create smooth epicardial and endocardial boundaries for both normal and abnormal regions. Third, using a thresholding technique based on the maximal myocardial activity, we determine the abnormal regions. Finally, with the abnormal regions and the myocardial mass determined, we can calculate the abnormality's size as a percentage of the total myocardial mass. By providing quantitative measurements, our technique meets the physician's long standing need for a volumetric quantitation of the size of myocardial perfusion abnormalities.

Malone, L. J.; Zeidler, James R.; Ku, Walter H.; Yeung, David W.

1994-09-01

128

Abnormal 201Tl limb scan due to unilateral tremor  

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A abnormal intra- and interextremity distribution pattern on 201Tl was observed on the limb scan of a patient with a unilateral tremor. This is ascribed to the increased blood flow in the muscles responsible for the tremor. The suggestion is made that the existence of tremor should be considered as a possible explanation for unexpected abnormalities on 201Tl limb scintigrams

129

Prediction of left ventricular dilatation with thallium-201 SPET imaging after primary angioplasty in patients with acute myocardial infarction  

International Nuclear Information System (INIS)

Progressive ventricular dilatation is an important prognostic factor in patients with acute myocardial infarction. We evaluated clinical, angiographic, echocardiographic and thallium-201 single-photon emission tomography (SPET) imaging variables predictive of the change in left ventricular volume during a 7-month follow-up period after primary angioplasty in patients with acute myocardial infarction. Thirty-six patients with first acute myocardial infarction treated with primary angioplasty within 12 h of onset underwent 201Tl SPET imaging (5.8±2.1 days after angioplasty). Changes in left ventricular volume were assessed over the 7-month period. The left ventricle dilated significantly after angioplasty (P201Tl uptake 2=0.41, P201Tl uptake 2 with positive and negative predictive values of 85% (17/20) and 75% (12/16), respectively. It is concluded that, following primary angioplasty in patients with acute myocardial infarction, the extent of myocardial infarction assessed by 201Tl SPET can identify those who will develop ventricular dilatation during the subsequent 7 months. (orig.)ng the subsequent 7 months. (orig.)

130

Gated single photon emission computer tomography for the detection of silent myocardial ischemia  

International Nuclear Information System (INIS)

Background: Asymptomatic patients with severe coronary atherosclerosis may have a normal resting electrocardiogram and stress test. Aim: To assess the yield of Gated Single Photon Emission Computer Tomography (SPECT) for the screening of silent myocardial ischemia in type 2 diabetic patients. Material and methods: Electrocardiogram, stress test and gated-SPECT were performed on 102 type 2 diabetic patients aged 60 ± 8 years without cardiovascular symptoms. All subjects were also subjected to a coronary angiography, whose results were used as gold standard. Results: Gated-SPECT showed myocardial ischemia on 26.5% of studied patients. The sensibility, specificity, accuracy, positive predictive value and negative predictive value were 92.3%, 96%, 95%, 88.8%, 97.3%, respectively. In four and six patients ischemia was detected on resting electrocardiogram and stress test, respectively. Eighty percent of patients with doubtful resting electrocardiogram results and 70% with a doubtful stress test had a silent myocardial ischemia detected by gated-SPECT. There was a good agreement between the results of gated-SPECT and coronary angiography (k =0.873). Conclusions: Gated-SPECT was an useful tool for the screening of silent myocardial ischemia

131

Evaluation of [201Tl](III) Vancomycin in normal rats  

International Nuclear Information System (INIS)

Tl-201 has potential in the preparation of radiolabelled compounds similar to its homologues, like In-111 and radiogallium. In this paper, recently prepared [20'1Tl](III) vancomycin complex ([201Tl](III)VAN) has been evaluated for its biological properties. [20'1Tl](III)VAN was prepared according to the optimized conditions followed by biodistribution studies in normal rats for up to 52 h. The Staphylococcus aurous specific binding was checked in vitro. The complex was finally injected to normal rats. Tracer SPECT images were obtained in normal animals and compared to those of 67 Ga-citrate. Freshly-prepared [201Tl](III)VAN batches (radiochemical yield ? 99%, radiochemical purity ? 98%, specific activity = 1.2 Ci/mmol) showed a similar biodistribution to that of unlabeled vancomycin. The microorganism binding ratios were 3 and 9 for tracer 201Tl3+ and tracer 201Tl(III)DTPA, respectively, suggesting the preservation of the tracer bioactivity. As a nonspecific cell penetrating tracer, [201Tl](III)DTPA was used. (authors)

132

Development of [201Tl](III-DTPA-human polyclonal antibody complex for inflammation detection  

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Full Text Available Objectives: There are a couple of radiotracers used in the detection of inflammation and infection in human, but just a few of them have been widely used in routine clinical trials. 111In-labeled HIG has been extensively tested in a large number of clinical studies. Due to interesting physical properties and wide availability of thallium-201 as a SPECT radionuclide, the idea of incorporation of this nuclide into human polyclonal immunoglubin (HIgG was targeted. Methods:Thallium-201 (T1/2=3.04 d in Tl+ form was converted to Tl3+ cation in presence of O3 in 6M HCl controlled by RTLC/gel electrophoresis methods. Human polyclonal antibody (HIgG was successively labeled with 201Tl-thallium chloride after residulation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of 1 ml of a HIgG pharmaceutical solution (5 mg/ml, in phosphate buffer, pH=8 to a glass tube pre-coated with DTPA-dianhydride (0.01 mg at 25?C with continuous mild stirring for 30 min. Preliminary in vivo studies in turpentine-oil induced inflammation in rat model was performed to determine complex distribution of the radioimmunoconjugate. Results: Total labeling and formulation of [201Tl](III-DTPA-HIgG took about 60 minutes, with a yield of 99%. A suitable specific activity product was formed via insertion of 201Tl cation. No unlabelled and/or labeled conjugates were observed upon RTLC analysis of the final preparations. The radio-labeled complex was stable in mice serum for at least 24 hours and no significant amount of free 201Tl as well as 201Tl-DTPA was observed. Trace amounts of 201Tl-thallium chloride (?1% were detected by TLC (radiochemical yield of >99%, specific activity =38 TBq/mM, radiochemical purity?98%. The preliminary SPECT at the 33.8 degree shows the absorbtion of the immunoconjugate in the dorsal inflammed lesion. The target/skin and target/blood ratio was 3 after 28h, showing the high selectivity of the radiopharmaceutical for the inflammatory lesions. The final preparation was administered to normal rats and biodistribution of the radiopharmaceutical was checked 1 and 6 hours later by scarification. Conclusion: there are lots of upportunities for radiopharmacist and interested nuclear medicine students to look at Tl-201 not only as a myocardial tracer but as a new radionulclide for kit formulations.

A.R. Jalilian

2006-06-01

133

Preparation and biodistribution of [201Tl](III vancomycin complex in normal rats  

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Full Text Available Objectives: Thallium-201 (T1/2=3.04d has been used in clinical nuclear cardiology and oncology for 3 decades. The development of [201Tl](IIIradiopharmaceuticals could provide many advantages: the chemistry of [201Tl](IIIcomplexation molecule is simple and the complexation constant for most of Tl(III complexes are among the highest. A wide variety of radiopharmaceuticals have been proposed for the scintigraphic detection of inflammatory and infectious disease. [67Ga]Citrate, being the most primitive radiotracer for this purpose, has a high sensitivity for both acute and chronic infections and noninfectious inflammation. Based on our previous experiences on the production and biological evaluation of radiolabelled glycopeptide antibiotics and vast clinical application of vancomycin for therapeutic purposes, we were interested in preparation of radiolabelled vancomycin as a possible infection imaging agent. Methods: Thallium-201 (T1/2=3.04 d in Tl+ form was converted to Tl3+ cation in presence of O3 in 6M HCl controlled by RTLC/gel electrophoresis methods. The final evaporated activity was reacted with vancomycin (VAN in water to yield [201Tl](IIIVAN after mixing the reactants followed by SPE purification using Si Sep-Pak. Radiochemical purity and stability of 201Tl-VAN in the preparation and in presence of human serum was determined up to 5.5 d. Biodistribution study of 201Tl(III-vancomycin in normal rats was performed up to 52 h. Results: The best results were obtained at room temperature in water after 30min with a radiochemical yield>99%, The studies showed that thallic ion is mostly incorporated into vancomycin with a radiochemical purity of more than 98?1% by RTLC. A specific activity of about 1.2 Ci/mmol was obtained. This pattern was also observed after IV injection to the normal rats at the same time intervals. Conclusion: [201Tl](IIIvancomycin, can be SPECT radiotracer with a rather long half life, meeting radiopharmaceutical standards for use in remote nuclear medicine centers. There are lots of opportunities for radiopharmacists and interested nuclear medicine students to look at Tl-201 not only as a myocardial tracer but as a new radionulclide for kit formulations.

A.R. Jalilian

2006-06-01

134

Functional images of the 4 h-washout: A quantitative assessment of 201Tl heart kinetics under stress - and an interpretation of ''reverse redistribution''  

International Nuclear Information System (INIS)

Between March and August 1983, 62 patients with suspected coronary artery disease were investigated by both 201Tl myocardial scintigraphy and coronary angiography. Functional images of the 4 h-201Tl-washout were compared with conventional scintigrams of the stress and rest phases and with results of coronary angiography. Myocardial scintigraphy with 4 views was performed immediately after exercise and 3-4 h later. After interpolative background subtraction, 4 h-washout functional images were computed from each of the initial scintigrams and the corresponding delayed scintigrams. Using a special-coded colour table, the 4 h-washout could be read quantitatively from the functional image. The additional analysis of washout images increased the accuracy of myocardial 201Tl scintigraphy for the detection and localization of coronary stenoses from 42% to 69%. Sensitivity increased from 42% to 73%, definitivity from 50% to 79%. Ischemic regions appeared more obvious in the washout images, even to less experienced observers. In comparison with circumferential washout profiles the interpretation of washout images was easier because of more obvious anatomical localization. The phenomenon of ''reverse redistribution'' was found to be associated with a decreased 201Tl-washout in apparently ''normal'' regions, whereas in those regions with ''reverse redistribution'' the washout was normal or at least relatively high. In addition diffuse mast relatively high. In addition diffuse myocardial ischemia occurring in 3-vessel disease could be recognized in the 4 h-201Tl-washout functional images. (orig.)

135

Detection of the viable myocardium. A perfusion scintigraphic study, before and after coronary bypass surgery in myocardial infarction patients  

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Full Text Available SciELO Brazil | Language: English Abstract in english OBJECTIVE: To compare single-photon-emission computed tomography (SPECT) imaging scans using 201Tl and 99mTc-MIBI in detection of viable myocardium, in regions compromised by infarction. METHODS: Thirty-two (59.3±9.8 years old and 87% male) myocardial infarction patients were studied. All had Q wave [...] s on the ECG and left ventricle ejection fraction of

Willliam A., Chalela; Paulo J., Moffa; José A. F., Ramires; Aguinaldo P., Moraes; José, Soares Jr; José C., Meneghetti.

1999-05-01

136

[Myocardial viability assessment and perioperative cardiovascular evaluation using single photon emission tomography and positron emission tomography].  

Science.gov (United States)

Nuclear cardiology including single photon emission computed tomography (SPECT) and positron emission tomography (PET) can play important roles as myocardial viability assessment and perioperative cardiovascular evaluation for noncardiac surgery. Increasing prevalance of coronary artery disease (CAD) is associated with an increasing number of patients with heart failure secondary to CAD. Three main therapies, medical, revascularizations, and heart transplantation, are currently available. Appropriate revascularization can improve left ventricular function, and hence could also improve an outcome. However, patients with reduced left ventricle (LV) function have higher perioperative cardiac risks. Therefore, it is important to evaluate the extent of myocardial viability to assist in deciding patient managements. In nuclear imaging, thallium-201 (201T1) SPECT, technetium-99m (99mTc) sestamibi SPECT, and 18F fluorodeoxyglucose (FDG) are applied for viability assessment. FDG is a glucose analogue and is used to measure myocardial glucose utilization. Among noninvasive imaging, FDG-PET is considered to be a standard measurement. Perioperative cardiovascular complications significantly deteriorate the outcome not only of the postoperative period but also over the subsequent 1 to 2 years. Intrathoracic noncardiac surgeries themselves are at intermediate or high perioperative risk. Thus, careful preoperative cardiac risk assessment is necessary for predicting cardiac complications. In the present review, we overview the present status of viability assessment and perioperative cardiovascular evaluation, and discuss some new approaches. PMID:17763661

Yoshinaga, Keiichiro

2007-07-01

137

Diagnosis of intracranial meningiomas by 201Tl-chlorine  

International Nuclear Information System (INIS)

Results are presented of a study of the use of 201Tl-chloride in the diagnosis of intracranial meningiomas. The meningiomas uniformly presented an intense 201Tl-chloride uptake. Factors such as vascularization increased and abnormal capillaries might play an important role in the tumoral fixation mechanisms. It was concluded that 201Tl-chloride imaging could be of particular interest in the diagnosis of intracranial meningiomas, especially in those cases that present a basal or infratentorial localization. It may also be useful as a post-surgery control method in the early detection of meningioma recurrence. The disadvantages of 201Tl-chloride are that it is an expensive radiopharmaceutical and its half-life limits the dose to be administered, thus not allowing the IBAS to be obtained. (U.K.)

138

Evaluating microvascular obstruction after acute myocardial infarction using cardiac magnetic resonance imaging and 201-thallium and 99m-technetium pyrophosphate scintigraphy  

International Nuclear Information System (INIS)

Few studies have compared the ability of cardiac magnetic resonance (CMR) with that of scintigraphy using 201-thallium (201-Tl) and 99m-technetium pyrophosphate (99m-Tc PYP) to evaluate microvascular obstructions (MOs). In the present study the relationship between the scintigraphic and CMR characteristics of MOs after acute myocardial infarction (MI) was examined. The 14 patients (age 69±8 years, 11 males) underwent 201-Tl/99m-Tc PYP single photon emission computed tomography (SPECT) 7±3 days, initial CMR 16±12 days, and follow-up CMR 193±20 days after a reperfused first acute MI. Each image was analyzed using a 17-segment model. Segmental extent of delayed enhancement (DE), wall motion (WM) and degree of 201-Tl uptake were scored in 238 segments. Of 91 MI segments, MO was recognized in 22 (25%) segments on CMR. WM was significantly better in proportion to 201-Tl uptake (P=0.01) in MO segments. All 8 MO segments with WM improvement at follow-up had 99m-Tc PYP uptake, although only 3 (21%) of 14 MO segments that did not show WM improvement at follow-up had 99m-Tc PYP uptake (P=0.001). 99m-Tc PYP and 201-Tl scintigraphy have the potential to predict WM status and improvement of the MO region after reperfused acute MI. (author)

139

Recovery of impaired left ventriculary function in patients with acute myocardial infarction is predicted by the discordance in defect sise on 123I-BMIPP and 201TI SPET images  

International Nuclear Information System (INIS)

A discrepancy between myocardial perfusion defect and wall motion abnormalities is frequently found early after coronary reperfusion in patients with acute myocardial infarction. The purpose of this study was to assess recovery of impaired left ventricular function by reference to the discordance in defect size between myocardial fatty acid uptake and myocardial perfusion using combined single-photon emission tomographic (SPET) imaging early after coronary perfusion therapy. In 37 patients with acute myocardial infarction, iodine-123 15-(p-iodophenyl)-3(R, S)-methylpentadecanoic acid (BMIPP) and thallium-201 SPET scans were performed early after coronary reperfusion. A severity score was determined from the extent of the imaging defect with each tracer. Left ventricular wall motion score (WMS) and injection fraction (EF) were obtained at admission and at 4 weeks after the onset of infarction. In 32 of the 37 patients, discordance in defect sizes delineated with the two SPET studies was found during the acute stage. The severity score for BMIPP was larger than that for 201Tl during the acute stage (7.7±2.4 vs 4.4±2.5, P201Tl and WMS. The extent of discordance in severity scores between BMIPP and 201Tl during the acute stage correlated well with the extent of the improvement in WMS (r=0.86, P201Tl SPET images during the acute stage of infarction is an early predictor of the viability of the myocardium at risk of infarction. (orig.)

140

Leg 201Tl-SPECT in chronic exertional compartment syndrome  

International Nuclear Information System (INIS)

Leg 201Tl-SPECT in chronic exertional compartment syndrome Background: The chronic exertional compartment syndrome is one of the most frequent origins regarding leg pain due to sport training. The diagnosis can be established by invasive compartment pressure measurement. The aim of this study is to evaluate the role that could have 201Tl-SPECT for patients with suspicion of compartment syndrome. Patients and methods: 51 leg 201Tl-SPECT exams were performed (exercise - and rest without reinjection) in 49 patients; 28 had compartment syndrome confirmed by pressure measurement. About 100 MBq of 201Tl were injected during exercise, when pain appeared or at least after 25 minutes exercise. We studied mean percentages of level uptake for each compartment, referred to the maximal uptake of both legs. Results: 47 compartments were concerned by compartment syndrome and 361 compartments were not. Scintigraphic patterns in compartments are reversible ischaemia (45%), uptake stability (36%) or reverse redistribution (19%); these patterns are not linked to compartment syndrome. However, there is a significant difference of rest 201Tl level uptake between compartments with and without compartment syndrome and a significant correlation between muscular pressure measurement and rest level uptake. Conclusion: 201Tl-SPECT shows that only ischaemia does not explain compartment syndrome. Moreover, it allows to predict presdrome. Moreover, it allows to predict pressure variation during exercise but it does not offer any interest in order to select patients for muscular invasive pressure measurement. (author)

 
 
 
 
141

The characteristics of syndrome X based on 201Tl-SPECT, 18 FDG-PET and histopathologic findings  

International Nuclear Information System (INIS)

Syndrome X is a microvascular disease. However, the relationship between microvascular ischemia and histopathological findings remains unknown. The present study was performed to evaluate the myocardial perfusion and metabolism of patients with Syndrome X using 201Tl-SPECT and 18FDG-PET, and to clarify the morphological characteristics with a ventricular myocardial biopsy. We examined 24 patients with Syndrome X and 5 patients with myocarditis as a control group. In the study using 201Tl-SPECT and 18FDG-PET, we evaluated the presence or absence of myocardial ischemia. We calculated the Standardized Uptake Value (SUV) (%dose/ml) of 18FDG, and analyzed quantitatively the degree of ischemia. For histopathologic study on coronary microcirculation, we performed a right ventricular myocardial biopsy. The biopsies were examined light and electron microscopically. The semithin sections, stained with toluidine blue, were projected onto a screen. Microvessels were counted and the ratio of microvascular luminal narrowing and the number of microvessels per unit area were determined. The study using 201Tl-SPECT and 18FDG-PET showed that hypoperfusion of 201Tl was found in 17 of 24 (71%) patients during 201Tl-loaded myocardial scanning together with redistribution of 201Tl at the same regions; 18FDG-uptake were found in all 24 patients during 18FDG-PETll 24 patients during 18FDG-PET performed under resting and fasting conditions; the SUV of 18FDG in the Syndrome X group (0.025±0.039 %dose/ml) was significantly different from that of the control group (0.003±0.002 %dose/ml) (p<0.01). Histopathological observations under the both light and electron microscope showed that an increment in number of the endothelial cells with swelling, a marked luminal narrowing due to the hypertrophy of the arteriolar media and the capillary walls, and a compression of the capillaries were shown in all the patients; the ratio of luminal narrowing of microvessels in the Syndrome X group was significantly higher than the control group (56.2±16.2% VS 12.2±2.9%, p<0.001); the number of microvessels in the Syndrome X group was more decreased than the control group (14.6±7.8 VS 21.5±10.0, p=0.124). Our results suggest that the characteristics of Syndrome X may be myocardial ischemia due to narrowness of microvessels with morphological abnormalities. (author)

142

Value of 123I-BMIPP scintigraphy in patients with ischemic heart disease. Comparison with exercise 201Tl SPECT  

International Nuclear Information System (INIS)

To evaluate 123I labeled beta-methyl-branched fatty acid (BMIPP) myocardial uptake at rest in the segment with and without stress induced ischemia in patients with coronary artery disease, 123I-beta-methyl-branched fatty acid myocardial scintigraphy was performed at rest and was compared with the findings of stress-reinjection 201Tl myocardial scintigraphy in 31 patients with coronary artery disease. In 159 ischemic myocardial segments, equally decreased uptake on both reinjection 201Tl and fatty acid images was observed in 64 segments, more severely decreased uptake of fatty acid in 76 segments, and more severely decreased uptake of reinjection thallium in 19 segments. On the other hand, in 53 non-reversible defects, each patterns was observed in 41, 3, and 9 segments respectively. When comparing the ischemic segments with more reduced uptake of fatty acid than reinjection thallium (Group 1) and the ischemic segments with equally or less reduced fatty acid uptake than reinjection thallium (Group 2), wall motion was more severely impaired in Group 1 than in Group 2 (severe hypo- to dyskinesis was present in 32 of 54 segments in group 1 and in 21 of 75 segments in group 2, p201Tl in the segments with stress induced ischemia and wall motion was more impaired in these segments. BMIP was more impaired in these segments. BMIPP myocardial imaging may provide information on metabolic alterations at rest independent of perfusion abnormalities in patients with coronary artery disease. (author)

143

Quality of myocardial perfusion single-photon emission tomography imaging: multicentre evaluation with a cardiac phantom  

International Nuclear Information System (INIS)

The aim of the study was to evaluate quality of myocardial perfusion single-photon emission tomography (SPET) imaging in Finnish hospitals. Nineteen nuclear medicine departments participated in the study. A myocardial phantom simulating clinical stress and rest conditions was filled with routinely used isotope solution (technetium-99m or thallium-201). The cardiac insert included three reversible defects (simulating ischaemia): 30 x 30 x 14 mm3 septal (90% recovery at rest), 30 x 20 x 14 mm3 posterobasal (full recovery) and 20 x 20 x 14 mm3 lateral (full recovery). There were two fixed defects (simulating infarct): 30 x 20 x 14 mm3 postero-apical and 10 x 10 x 6 mm3 apical. The phantom was imaged and interpreted as a myocardial perfusion patient. Reconstruction, printout and reporting were performed according to the clinical routine of each centre. Three nuclear medicine specialists anonymously evaluated the quality of the image sets. The visual scores of the experts were ranked from 1 to 5. Additionally, points from 0 to 8 were given to research reports according to how well perfusion defects were detected. Quantitative points were calculated by comparing background-subtracted and -normalized counts from 12 regions of interest between stress and rest images. Results for technetium studies (12 departments) were better than those for thallium (7 departments). The average visual scores of the experts were 3.7±0.9 fsual scores of the experts were 3.7±0.9 for all image sets, 3.2±0.5 for thallium users and 3.9±0.6 for technetium users (P=0.003). Five laboratories received a low score which, according to the specialists, is barely sufficient for limited clinical use. Average points for the reports were 5.6±2.1, 4.9±1.5 and 6.5±1.7 (P=0.051), and for the quantitation 8.2±1.0, 7.9±0.4 and 8.4±1.1 (P=0.185), respectively. Seven out of 22 interpreters did not detect the lateral 20 x 20 x 14 mm3 defect; five of them used thallium. This study demonstrated the heterogeneity of myocardial perfusion SPET in Finland. The participating laboratories used a wide scale of methods and, sometimes, inappropriate imaging protocols. The need for quality assurance in nuclear cardiology, correct use of SPET instrumentation and objective comparison of clinical studies is evident. The method described is suitable for external quality assurance and quality improvement of myocardial SPET imaging, and is recommended for regular use in nuclear medicine. (orig.)

144

Usefulness of isoproterenol stress thallium-201 myocardial single photon emission computed tomography (SPECT)  

International Nuclear Information System (INIS)

Twenty patients complaining of chest pain were referred for isoproterenol stress thallium-201 myocardial single photon emission computed tomography (ISO-SPECT). The findings were compared with those obtained from isoproterenol stress ECG testing (ISO-ECG) and exercise SPECT (EX-SPECT). Isoproterenol was iv injected in a dose of 0.02 ?g/kg/min. The amount was continuously increased until limited by chest pain, ST depression, and/or determined heart rate criteria. The patients were scanned immediately and three hours after giving isoproterenol. Transient hypoperfusion was regarded as myocardial ischemia. Washout rate, obtained from circumferential profile analysis on the short axis SPECT images, was expressed by Bull's eye display. Fifteen patients with angiographically significant stenosis of 75% or greater were diagnosed as having coronary artery disease (CAD). The other five patients had normal coronary artery (NC). In diagnosing CAD, ISO-ECG and ISO-SPECT had a sensitivity of 80% and 92%, respectively. Because the NC group had negative findings for redistribution on ISO-SPECT, the specificy of ISO-SPECT seemed to be high. For multi-vessel disease, redistribution on ISO-SPECT tended to underestimate coronary lesions. The underestimation was, however, corrected by calculating washout rate. For evaluable 11 patients undergoing concurrent EX-SPECT, ISP-SPECT was equivalent or superior to EX-SPECT in diagnostic sensitivity. None of the patients had severe side effects oof the patients had severe side effects of isoproterenol, except for some having arrhythmia. The results indicated that ISO-SPECT is a safe, high sensitive diagnostic approach that is comparable to Ex-SPECT. (N.K.)

145

Detection of myocardial infarction with dual energy CT myocardial iodine maps and perfusion myocardial single photon emission computed tomography scintigraphy: an experimental study in canine  

International Nuclear Information System (INIS)

Objective: To investigate the feasibility and accuracy of dual energy CT myocardial iodine maps in detecting acute myocardial infarction in canine model. Methods: Myocardial ischemia model was made by ligaturing left anterior descending coronary arteries (LAD) after thoracotomy in six dogs, while another 3 dogs undergoing thoracotomy not ligaturing LAD as control group. Before and three hours after operation, dual-source CT (DSCT) was performed, followed by resting 99Tcm-MIBI single photon emission computed tomography myocardial perfusion imaging. Then, dogs were sacrificed, and the hearts were removed, triphenyketrazolium chloride staining and conventional HE staining were performed. CT number of non-ischemic and ischemic regions were measured and analyzed. The wall of the left ventricle in the short axis was divided into 17 segments, the segments of myocardial perfusion defect in DSCT myocardial iodine maps, SPECT, and pathology were determined. Student t test was used to analyze the difference of CT number between infarcted and non-infarcted myocardium. Kappa test was used for the accuracy of DSCT myocardial iodine maps and SPECT in detecting myocardial ischemia according to the pathological results. Results: No abnormal regions were detected using DSCT myocardial iodine maps in preoperative control and infarction group. After thoracotomy, partial sparse or defective perfusion was consistently noted in six dogs' apical anterior and partition wall in both DSCT myocardial iodine maps and SPECT. In the infarcted group, the attenuation of infarction region (34.75±16.66) HU was significantly decreased compared with preoperative measurements (123.18±15.38 ) HU (t=10.526, P<0.01); decreased perfusion in the infarcted region was also noted in the DSCT myocardial iodine maps and SPECT. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT myocardial iodine maps and SPECT were 85.0% (34/40), 84.1% (95/113), 65.4% (34/52), 94.0% (95/101), and 82.5% (33/40), 90.3% (102/113), 75.0% (33/44), 93.6% (102/109), respectively. Kappa values were 0.63 and 0.71 for the agreement of DSCT myocardial iodine maps and SPECT. Conclusion: DSCT myocardial iodine maps is comparable diagnostic accuracy with rest SPECT myocardial perfusion imaging in detection of acute myocardial infarction in a canine model. (authors)

146

Cardiac phase-synchronized myocardial thallium-201 single-photon emission tomography using list mode data acquisition and iterative tomographic reconstruction  

International Nuclear Information System (INIS)

The purpose of this study was to determine whether data acquisition in the list mode and iterative tomographic reconstruction would render feasible cardiac phase-synchronized thallium-201 single-photon emission tomography (SPET) of the myocardium under routine conditions without modifications in tracer dose, acquisition time, or number of steps of the a gamma camera. Seventy non-selected patients underwent 201Tl SPET imaging according to a routine protocol (74 MBq/2 mCi 201Tl, 180 rotation of the gamma camera, 32 steps, 30 min). Gamma camera data, ECG, and a time signal were recorded in list mode. The cardiac cycle was divided into eight phases, the end-diastolic phase encompassing the QRS complex, and the end-systolic phase the T wave. Both phase- and non-phase-synchronized tomograms based on the same list mode data were reconstructed iteratively. Phase-synchronized and non-synchronized images were compared. Patients were divided into two groups depending on whether or not coronary artery disease had been definitely diagnosed prior to SPET imaging. The numbers of patients in both groups demonstrating defects visible on the phase-synchronized but not on the non-synchronized images were compared. It was found that both postexercise and redistribution phase tomograms were suited for interpretation. The changes from end-diastolic to end-systolic images allowed a comparative assessment of regional wall motility and tracer uptake. End-diastolic tomogrty and tracer uptake. End-diastolic tomograms provided the best definition of defects. Additional defects not apparent on non-synchronized images were visible in 40 patients, six of whom did not show any defect on the non-synchronized images. (orig./VHE)

147

Study of 201Tl uptake by bone and bone marrow on 201Tl scintigraphy  

International Nuclear Information System (INIS)

Thallium-201 (Tl-201) uptake in the bone and bone marrow was examined in a total of 93 patients with various diseases. Sternal uptake of Tl-201 was observed when patients had bone marrow abnormality especially associated with hematopoietic disease. It was associated with proliferation of immature cells and of various types of bone marrow cells, especially erythroblastic and plasma cells. Whole-body Tl-201 scanning showed a high uptake (82%) in the sternum, chest, lumbar vertebrae, and pelvis. Thallium-201 was definitively taken up by the sternum in polycythemia (5/41), hemolytic anemia (2/2), iron deficiency anemia (2/2), and multiple myeloma (2/5). For leukemia, Tl-201 uptake was slight or negative. Thallium-201 scanning proved useful in visualizing bone marrow abnormality, although careful interpretation of bone and bone marrow uptake is required. (Namekawa, K)

148

Attenuation correction in pulmonary and myocardial single photon emission computed tomography  

Energy Technology Data Exchange (ETDEWEB)

The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiologic and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. A protocol based upon geometrically well defined phantoms was developed. In a mosaic pattern phantom count rates were corrected from 39-43% to 101-110% of reference. In healthy subjects non-gravitational pulmonary perfusion gradients observed without attenuation correctionwere artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 {+-} 0.03 g/ml in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer {sup 133}Xe. Because of the low energy of {sup 133}Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one of the systems provided correct emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study.

Almquist, H

2000-01-01

149

Attenuation correction in pulmonary and myocardial single photon emission computed tomography  

International Nuclear Information System (INIS)

The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiologic and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. A protocol based upon geometrically well defined phantoms was developed. In a mosaic pattern phantom count rates were corrected from 39-43% to 101-110% of reference. In healthy subjects non-gravitational pulmonary perfusion gradients observed without attenuation correction were artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 ± 0.03 g/ml in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer 133Xe. Because of the low energy of 133Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one of the systems provided correct emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study

150

Transmission-based scatter correction of 180 C myocardial single-photon emission tomography studies  

International Nuclear Information System (INIS)

Meaningful comparison of single-photon emission tomographic (SPET) reconstructions for data acquired over 180 or 360 can only be performed if both attenuation and scatter correction are applied. Convolution subtraction has appeal as a practical method for scatter correction; however, it is limited to data acquired over 360 . A new algorithm is proposed which can be applied equally well to data acquired over 180 or 360 . The method involves estimating scatter based on knowledge of reconstructed transmission data in combination with a reconstructed estimate of the activity distribution, obtained using attenuation correction with broad beam attenuation coefficients. Processing is implemented for planes of activity parallel to the projection images for which a simplified model for the scatter distribution may be applied, based on the measured attenuation. The appropriate broad beam (effective) attenuation coefficients were determined by considering the scatter buildup equation. It was demonstrated that narrow beam attenuation coefficients should be scaled by 0.75 and 0.65 to provide broad beam attenuation coefficients for technetium-99m and thallium-201 respectively. Using a thorax phantom, quantitative accuracy of the new algorithm was compared with conventional transmission-based convolution subtraction (TDCS) for 360 data. Similar heart to lung contrasts were achieved and correction of 180 data yielded a 10.4% error for cardiac activity compared to 5.2% for TDCS. Contr activity compared to 5.2% for TDCS. Contrast for myocardium to ventricular cavity was similarly good for scatter-corrected 180 and 360 data, in contrast to attenuation-corrected data, where contrast was significantly reduced. The new algorithm provides a practical method for correction of scatter applicable to 180 myocardial SPET. (orig.)

151

Serial right ventricle 201Tl imaging after exercise: relation to anatomy of the right coronary artery  

International Nuclear Information System (INIS)

The relation of the appearance of the right ventricle on serium 201Tl myocardial imaging to coronary artery anatomy was examined in 88 consecutive patients undergoing exercise 201Tl testing and coronary angiography for the evaluation of chest pain. Transient defects in the right ventricle were found in 8 patients. All had high grade (greater than or equal to 90%) stenosis of the proximal right coronary artery. Nonvisualization of right ventricular (RV) activity occurred in 10 patients. Nine of the 10 (90%) had significant (greater than or equal to 50% stenosis) disease of the proximal right coronary artery and 7 (70%) had high grade stenosis. The right ventricle appeared normal in 70 patients. Twenty-nine (41%) of these patients had significant proximal right coronary artery disease. Right ventricular appearance was not affected by the presence or absence of disease of the left anterior descending or left circumflex artery or by the appearance of the left ventricle. Thus, with serial RV thallium-201 myocardial imaging after exercise, we found that (1) RV transient defects suggest the presence of high grade proximal right coronary artery stenosis, (2) non-visualization of RV activity also predicts significant proximal right coronary disease, and (3) the right ventricle frequently appears normal despite proximal right coronary artery disease and therefore this finding does not exclude such disease

152

Evaluating image denoising methods in myocardial perfusion single photon emission computed tomography (SPECT) imaging  

International Nuclear Information System (INIS)

The statistical nature of single photon emission computed tomography (SPECT) imaging, due to the Poisson noise effect, results in the degradation of image quality, especially in the case of lesions of low signal-to-noise ratio (SNR). A variety of well-established single-scale denoising methods applied on projection raw images have been incorporated in SPECT imaging applications, while multi-scale denoising methods with promising performance have been proposed. In this paper, a comparative evaluation study is performed between a multi-scale platelet denoising method and the well-established Butterworth filter applied as a pre- and post-processing step on images reconstructed without and/or with attenuation correction. Quantitative evaluation was carried out employing (i) a cardiac phantom containing two different size cold defects, utilized in two experiments conducted to simulate conditions without and with photon attenuation from myocardial surrounding tissue and (ii) a pilot-verified clinical dataset of 15 patients with ischemic defects. Image noise, defect contrast, SNR and defect contrast-to-noise ratio (CNR) metrics were computed for both phantom and patient defects. In addition, an observer preference study was carried out for the clinical dataset, based on rankings from two nuclear medicine clinicians. Without photon attenuation conditions, denoising by platelet and Butterworth post-processing methods outperformed Butterworth pre-processing for large size defects, while for small size defects, as well as with photon attenuation conditions, all methods have demonstrated similar denoising performance. Under both attenuation conditions, the platelet method showed improved performance with respect to defect contrast, SNR and defect CNR in the case of images reconstructed without attenuation correction, however not statistically significant (p > 0.05). Quantitative as well as preference results obtained from clinical data showed similar performance of the denoising methods studied. In conclusion, the multi-scale platelet denoising method applied on raw projection images provides more efficient noise reduction while preserving image quality in a myocardial phantom SPECT imaging as compared to the Butterworth filter applied either on projection or reconstructed images. However, this trend in favour of the platelet denoising method was not observed on clinical data reconstructed either without or with attenuation correction

153

Serial evaluation of 123I-BMIPP/201Tl myocardial single-proton emission computed tomography after coronary stent implantation in ischemic heart disease. Association with recovery of left ventricular function  

International Nuclear Information System (INIS)

Coronary stent implantation is often used to treat ischemic heart disease. However, few studies have evaluated myocardial viability with single-proton emission computed tomography (SPECT) and both thallium and ?-methyl-iodophenyl-pentadecanoic acid (BMIPP) after coronary stent implantation. Forty patients (30 men and 10 women, 64.8±9.3 years old) who had undergone successful stent implantation were enrolled. Twenty-two patients had angina pectoris (AP) and 18 patients had acute myocardial infarction (AMI). We performed BMIPP and thallium SPECT immediately after coronary stent implantation and at 3 months follow-up and compared the results with left ventriculograms. Myocardial SPECT images were divided into 17 segments, after which defect scores (1 to 5) were assigned to each segment and summed to obtain a total defect score (TDS). Left ventriculograms were divided into 9 segments, each of which was given a wall motion score (WMS; 1 to 5). In patients with either AP or AMI, the TDS of BMIPP and thallium SPECT images were significantly better at 3 months follow-up than immediately after stent implantation. In patients with AP, improvements in TDS on BMIPP and thallium SPECT were not associated with improvements in WMS. In patients with AMI, improvements in TDS on BMIPP SPECT were correlated with improvements in WMS (r=0.69, p<0.01) and in left ventricular ejection fraction (r=0.70, p<0.01), and improvements in TDS on thallium SPECT were correlated with improvements inECT were correlated with improvements in WMS (r=0.64, p<0.01) but were not associated with improvements in left ventricular ejection fraction. In conclusion, a decrease in BMIPP myocardial uptake in patients with AP suggests previous episodes of severe myocardial ischemia. Improvements in BMIPP uptake in patients with AMI may indicate recovery of left ventricular function. Coronary stent implantation for severe myocardial ischemia contributes to improvements in myocardial viability. (author)

154

Comparison of positron tomography and scintigraphy with 201Tl for delineation of the myocardium  

International Nuclear Information System (INIS)

Recent advances in nuclear medicine instrumentation have led to the development of improved positron-imaging systems which exceed in performance the earlier systems which were limited mainly by low count rate capability. This has led to renewed interest in positron imaging in general, primarily because such devices offer better resolution and higher sensitivity than conventional, mechanically collimated gamma cameras, as well as tomographic capability which may provide additional and more accurate information for the clinician. Furthermore, the unique capabilities of positrons for use in reconstructive imaging are beginning to be exploited. In the present report, results are presented from a preliminary study in which longitudinal tomographic myocardial images, produced with 81Rb as the positron-emitting label using the double camera coincidence system are compared with conventional myocardial images obtained with 201Tl and a gamma camera

155

Perfusion and thallium single photon emission computed tomography in herpes simplex encephalitis.  

Science.gov (United States)

This is the first report on 201thallium-single photon emission computed tomography (201Tl-SPECT) brain scan of a patient with herpes simplex encephalitis (HSE). The presented 201Tl-SPECT observations are correlated with 99mtechnetium hexamethylpropylene amine oxime (99mTc-HMPAO) perfusion SPECT and magnetic resonance imaging (MRI) findings. Brain 99mTc-HMPAO perfusion SPECT reveals a hyperperfusion in the right temporal lobe with extension to the parietal lobe and a hypoperfusion in the ipsilateral occipital lobe. 201Tl-SPECT shows a fixation in the right temporal lobe coinciding with the gadolinium enhancement on MRI. The right occipital lesion shown by gadolinium captation on MRI and hypoperfusion on 99mTc-HMPAO perfusion SPECT was not evident on the 201Tl SPECT. These findings could illustrate that the lesions might be different pathophysiologically. PMID:9600683

De Deyn, P P; Van den Broucke, P W; Pickut, B A; Appel, B; Crols, R; Cras, P; Martin, J J

1998-04-15

156

Safety of and tolerance to adenosine infusion for myocardial perfusion single-photon emission computed tomography in a Japanese population  

International Nuclear Information System (INIS)

Adenosine has been available for use in myocardial perfusion single-photon emission computed tomography (SPECT) in Japan since 2005. The purpose of this study was to evaluate the safety of and tolerance to thallium-201 myocardial perfusion SPECT with intravenous adenosine infusion in Japanese patients with suspected coronary artery disease. Two hundred and six consecutive patients who underwent an adenosine infusion (120 ?g·kg-1·min-1) SPECT at Sumitomo Besshi Hospital (Niihama, Japan) were investigated. The effects of adenosine infusion were monitored for each patient. A coronary angiography was performed in 81 patients. Adenosine infusion significantly decreased blood pressure and increased heart rate. Adverse reactions were observed in 161 patients (78.2%). Most reactions were transient, disappearing soon after the termination of adenosine infusion. No serious adverse reactions, such as acute myocardial infarction or death, occurred. Adenosine infusion was terminated in 3 patients (1.5%) because of near syncope or sustained 2:1 atrioventricular block. Electrocardiographic changes occurred in 15 patients (7.3%). Self-assessed scoring after SPECT showed that the patients were very tolerant (74.6% of 177 patients) of adenosine infusion myocardial SPECT. The sensitivity and specificity were 75.0% and 69.7%, respectively. Adenosine infusion myocardial SPECT is safe and well tolerated in the Japanese population, despite the frequent occurrence ofion, despite the frequent occurrence of minor adverse reactions. (author)

157

Dose redistribution in exercise thallium-201 single photon emission computerized tomography represent residual ischemia in old myocardial infarction?  

International Nuclear Information System (INIS)

To explore whether redistribution in infarct-related area in exercise thallium-201 single photon emission computerized tomography (Ex-Tl SPECT) represents residual ischemia, 100 patients with antero-septal old myocardial infarction (OMI) were studied. ?% Tl-uptake, the index of the degree of redistribution was calculated as a difference of % Tl-uptake in infarct-related area between initial and delayed images. Lactate extraction ratio (LER), the index of the degree of regional myocardial ischemia was obtained from a difference of lactate concentration between aorta and great cardiac vein during atrial pacing stress test (from 90 to 150 bpm) undergone within a week after Ex-Tl SPECT. Each ?% Tl-uptake of 41 patients with LER0 (non-ischemic group) was 12.7±7.2 and 3.5±4.6 (mean±SD, p10) represents evident residual ischemia in OMI (maximal value of ?% Tl-uptake in non-ischemic group was 10). (author)

158

Utility of QGS for {sup 201}Tl electrocardiogram-gated SPECT in cardiac function evaluations  

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QGS (quantitative gated SPECT) was applied to {sup 201}Tl SPECT, whose images are inferior to those of Tc SPECT, and its utility was evaluated. More specifically, the cardiac function index was calculated by QGS, and local wall motion was evaluated visually. Accuracy was assessed by comparison with left ventriculography. The subjects were 29 patients (21 males, 8 females; 6 with myocardial infarction, 18 with stenocardia, 2 with pericardial disease, 3 with other heart diseases) who had undergone myocardial scintigraphy and left ventriculography between February and May, 2000. {sup 201}Tl (74 or 111 MBq) was administered to all patients. The resting image was obtained 10 minutes later, and the delayed image during loading was obtained 4 hours later. The conditions for acquiring the images were as follows. Two detectors were arranged at a 90-degree angle in the form of an L. The 180 degrees from 45 degrees right anterior oblique (RAO) to 45 degrees left posterior oblique (LPO) were divided into 30 sections at 6-degree intervals, and the image in each section was acquired for 60 seconds. The matrix was 64 x 64. As a cardiac function index, the left ventricular ejection function (LVEF) obtained by electrocardiogram-gated SPECT (QGS-EF) at the rest (14 cases) and the QGS-EF on the delayed images (15 cases) were compared with the LVEF determined by left ventriculography (LVG-EF). There was an excellent positive correlation between the data obtained by two methods, with a correlation coefficient of r=0.93 (y=1.04x-0.04). Most of the difference between the values fell within two standard deviations, and the error was in the clinically allowable range. There was no significant difference between the correlation coefficient at rest and during loading or between the cases that showed an obvious defect on the image and those that did not. The local wall motion of the left ventricle was visually evaluated in five stages in two directions (RAO, 30 degrees, and LAO, 60 degrees). The motion scores in the QGS image and the LVG image agreed in 124 (67.4%) of 184 areas. A difference of one level in the score was shown in 42 areas (22.8%) and a difference of 2 or more levels in the score in 18 areas (9.8%). The results demonstrated that evaluation of myocardial blood-flow functions by {sup 201}Tl electrocardiogram gated SPECT is possible. (K.H.)

Shimazaki, Hiroshi; Oono, Ryuichi [Sapporo Kosei Hospital (Japan)

2001-07-01

159

The importance of mild inferolateral wall ischemia on myocardial single photon emission computed tomography (SPECT) with 99mTc-MIBI using 20 left ventricular segments model  

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Introduction: The mild ischemia in the inferolateral wall on myocardial perfusion imaging was seen frequently in practice .The aim of this study is to assess the importance of the above issue on myocardial perfusion SPECT with coronary angiography. Methods: All patients with mild ischemia of the inferolateral wall on the myocardial single photon emission computed tomography with 99mTc-MIBI using 20 left ventricular segments model were enrolled to this study. For all cases, a questionnaire inc...

Majid Assadi; Alireza Abdi-Ardekani; Mohammad Reza Pourbehi; Lati Amini; Hamid Javadi; Moloud Abbaszadeh; Mahsan Assadi

2010-01-01

160

Role of myocardial perfusion single photon emission computed tomography in pediatric cardiology practice  

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Full Text Available Diagnostic and prognostic power of myocardial perfusion imaging in patients with coronary artery disease has been demonstrated with planar imaging which was further improvised with addition of gated SPECT and newer Technetium labeled myocardial perfusion tracers like SestaMIBI, Tetrofosmin. Myocardial perfusion abnormalities at rest and after stress are considered to be the best predictors of cardiac event-free survival in adults with ischemic heart disease. This article highlights various myocardial perfusion imaging (MPIradiopharmaceuticals, exercise procedures, pharmacological stress protocols, indications for MPI and myocardial perfusion patterns in children with some of the common congenital and acquired heart diseases.

Sundaram P

2009-01-01

 
 
 
 
161

Use of ECG-gated single-photon emission tomography to assess the evolution of perfusion after acute myocardial infarction  

International Nuclear Information System (INIS)

Serial improvement in myocardial perfusion images from the acute or subacute to the chronic stage of acute myocardial infarction (AMI) has been attributed to improved coronary microcirculation or cell function after acute ischaemia and reperfusion. However, conventionally used non-gated imaging cannot eliminate the effect of improved regional contraction. We studied the possibility that such scintigraphic improvement reflects the functional recovery by using ECG-gated myocardial perfusion imaging with technetium-99m sestamibi. Nineteen AMI patients who received acute reperfusion therapy underwent ECG-gated myocardial single-photon emission tomography (SPET) in the subacute and chronic stages. Serial changes in regional image count distributions were analysed on the non-gated, end-diastolic (ED) and end-systolic (ES) images by using segmental mean percent peak activity (MPA) and ?MPA (MPA in chronic stage - MPA in subacute stage) on bull's-eye polar maps. These changes were compared with those in regional wall motion on biplane left ventriculography (LVG) from the acute (just after reperfusion) to the chronic stage. During the follow-up, regional wall motion remained the same in 42 (group A) but improved in 17 (group B) of the 59 ischaemically compromised segments. MPA showed no improvement in group A but significant improvement in group B on the non-gated and ES images (P<0.0001 and P<0.001, respectively). However, MPA on the ED images showed no improvement in eitherED images showed no improvement in either group. In the follow-up study of AMI, the scintigraphic improvement documented on the non-gated myocardial images appears to be mainly related to the recovery of wall thickening and not to a real improvement in myocardial perfusion. Therefore, ECG-gated myocardial imaging, which enables simultaneous assessment of changes in perfusion and contraction, is preferable to conventional non-gated imaging for follow-up of AMI. (orig.)

162

Single photon radionuclide computed tomography with Tomogscanner II, (1)  

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The single photon radionuclide computed tomography (RCT) was examined in 214 patients with the Tomogscanner-II. The RCT of brain was superior to the conventional brain scan, especially in the detection of lesions at the base of brain or the postoperated condition. The blood pool RCT of brain depicted an arterio-venous malformation and a giant aneurysma at the base of brain. The RCT of cisternography was useful to understand the anatomical relationship of the activity. The RCT of cerebral blood perfusion was possible with a method of continuous infusion of sup(81m)Kr into an internal carotid artery. In the body study, the reconstructed image of the Tomogscanner was excellent. The area of myocardial infarction showed clear defect in the horse-shaped myocardial section image after injection of 4 mCi of 201TlCl. The RCT of liver was available to detect defects and evaluated the activity and size of spleen. The RCT of kidney, lung or bone also showed good image, respectively. The Tomogscanner-II gave very good images in clinical examination of body as well as brain. (author)

163

123I-HDA and 201Tl-chloride: A comparative study in coronary artery disease  

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By means of the 7-pinhole collimator technique 21 patients with CAD and 7 patients with acute myocardial infarction were examined scintigraphically both with 201-Tl and 123-I-Heptadecanoic acid. The results obtained with both tomographic techniques were concordant. MI's and scars are displayed in the same fashion as regions of diminished or absent accumulation of radioactivity. Some of the patients with acute MI present the defect in the fatty acid scintigram as cold-warm-lesion, i.e. diminished tracer accumulation in the early image and fill-in in the late image (so-called d-type-lesion). These lesions were not observed in cases of stress induced ischemia. Therefore it is not possible to sustain hypothesis that these lesions correlate with borderline perfused myocardium. (Author)

164

Nucleomedical classification of lung cancer using quantitative 201Tl and 67Ga scans  

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The possibility of nucleomedical classification of lung cancer was studied by estimating 201Tl and 67Ga uptake by the tumors. Many adenocarcinomas took up much more 201Tl than 67Ga, whereas epidermoid carcinomas took up much more 67Ga than 201Tl. Adenosquamous carcinomas showed an intermediate uptake between adenocarcinomas and epidermoid carcinomas. The measurement of 201Tl and 67Ga uptake by the tumors was found to enable not only a nucleomedical classification but a presumption of various histogeneses in lung cancer. (orig.)

165

201Tl scintigraphy in postoperative detection of thyroid cancer: a comparative study with 131I  

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201Tl scintigraphy was performed to visualize malignant lesions postoperatively in 28 patients with thyroid cancer. The results were compared with those of 131I and/or /sup 99m/Tc pertechnetate scintigraphy. Of eight patients who had malignant lesions and no normal thyroid tissue, 201Tl concentration was observed in seven, while 131I concentration was observed in only three. All of four patients who had malignant lesions and did have remaining normal thyroid tissue showed concentrations of 201Tl. 201Tl scintigraphy can be performed without any preparation and may be useful in depicting residual and recurrent lesions regardless of the presence of normal thyroid tissue

166

Technetium-99m sestamibi and tetrofosmin myocardial single-photon emission tomography: can we use the same reference data base?  

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The aim of this study was to compare technetium-99m labelled tetrofosmin and sestamibi myocardial perfusion single-photon emission tomography (SPET) with one common sestamibi reference file for bull's eye imaging, with quantitation of the extent and severity of perfusion defects. Twenty patients suspected or known to have coronary artery disease participated in the study. Patients first underwent routine sestamibi myocardial SPET over 2 days, receiving doses of 400-600 MBq at stress and 600-800 MBq at rest. Then within the same week a 1-day tetrofosmin myocardial SPET study was performed, with a dose of 300 MBq at stress, followed 2.5 h later by a dose of 750 MBq at rest. Bull's eye images were generated for visual evaluation. Black-out defects according to the Cequal software analysis were only recorded if they comprised more than 10 pixels in men and 20 in women. According to the Cequal program, extent score and severity scores were expressed as number of pixels and deviations below reference limits. Five patients had normal myocardial SPET imaging with both radiotracers, while 15 had reversible, irreversible or partially reversible defects. The concordance of the results was high. The only two significant differences were that one patient had a reversible defect which appeared to be located in different myocardial regions (LAD vs RCA), and another patient had a defect that was partially reversible with sestamibi but irreversible with tetrofosmin. The results showedsible with tetrofosmin. The results showed very high correlation coefficients for the extent and severity scores (linear correlation coefficient values of 0.99 and 0.94, respectively). In conclusion, it appears that changing between sestamibi and tetrofosmin has little influence on the interpretation of bull's eye images from the data file of a common reference population using one of the tracers. (orig.). With 3 figs., 3 tabs

167

Quantitative myocardial thallium single-photon emission computed tomography in normal women: demonstration of age-related differences  

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The aim of this study is the development of a database of normal women for quantitative analysis of exercise and reinjection myocardial single-photon emission computed tomography (SPET). We studied 101 subjects (40 males and 61 females) with less than 5% likelihood of coronary artery disease. All patients underwent stress and rest thallium-201 myocardial SPET. Myocardial stress was induced by bicycle exercise test (n=51), dipyridamole infusion (n=27) or a combined test (n=23). Multivariate ANOVA showed that the type of stress did not influence the percentage of thallium uptake for each region. Significant differences between men and women were found for the percentage of uptake in the inferior and the anterior wall. The most original finding of this study is the correlation between age and thallium uptake in the three regions of the anterior wall, showing an increase in measured thallium uptake with age for women. Consequently, two groups of women, those under and those over 55 years old, were separated, with a significantly lower tracer uptake in the anterior wall in the younger age group. (orig./MG)

168

Single-photon emission computerized tomography for the determination of a site and extent of acute myocardial infarction  

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Results of plane santigraphy of myocardium (PSM) and single-photon emission computerized tomography (SPECT) of heart with 99mTc-pyrophosphate are compared to study diagnostic value of the latter in the determination of focal changes in myocardium, ascertaining localization and propagation of the disease focus in patients with myocardial infarction (MI). 40 patients have been examined. Localization and propagation of the process were determined by the inclusion of RP in necrosis focus at a certain number of sections. It is ascertained that SPECT permits to determine IM localization and its propagation more precisely than PSM. For IM of front localization (according to SPECT data) sections in all orthogonal planes proved to be informative, for IM of lower localization-saggital and frontal ones, and for the lateral IM - axial and frontal sections

169

Assessment of regional myocardial uptake and metabolism of #betta#-(p-123I-phenyl) pentadecanoic acid with serial single-photon emission tomography  

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The utility of myocardial imaging and assessment of regional myocardial metabolism of #betta#-(123I-paraphenyl-)pentadecanoic acid (I-PPA) by means of serial single-photon tomography is demonstrated in animal experiments. High quality cross sectional images of dog hearts with clear delineation of left ventricular walls are obtained. Myocardial infarcts are visualized as areas of deficient radioactivity uptake. I-PPA elimination from non-infarcted myocardial regions is significantly (p < 0.001) prolonged when compared with unaffected controls. Hence, not only localized absence of uptake of free fatty acid by infarcted myocardium can be demonstrated with serial single-photon tomography but also general impairment of cardiac FFA-metabolism. (orig.)

170

Retention index of thallium-201 single photon emission computerised tomography (SPECT) as an indicator of metastasis in adenocarcinoma of the lung.  

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We examined the relationship between the retention of thallium-201 (201Tl) on a delayed scan and the metastatic potential of adenocarcinomas of the lung. We studied 43 patients with adenocarcinoma of the lung and divided them into two groups according to the presence or absence of lymph node metastasis. 201Tl single photon emission computerised tomography (SPECT) was conducted twice: 15 min (early scan) and 120 min (delayed scan) after intravenous injection of 3 mCi of 201Tl chloride. We calc...

Takekawa, H.; Itoh, K.; Abe, S.; Ogura, S.; Isobe, H.; Sukou, N.; Furudate, M.; Kawakami, Y.

1994-01-01

171

Semi-quantitative assessment of oral cavity squamous cell carcinoma using 201Tl SPECT for evaluating effectiveness of preoperative radiotherapy  

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The aim of this study is to reveal the usefulness of semi-quantitative assessment using 201Tl chloride (Tl) single photon emission computed tomography (SPECT) (Tl SPECT) to evaluate the effectiveness of radiotherapy in 15 patients with oral cavity squamous cell carcinoma (SCC). Fifteen patients were diagnosed with SCC by biopsy. All 15 patients enrolled in this study were planned to undergo preoperative radiotherapy with or without chemotherapy using carboplatin (CBDCA) and received reduction operation. Tl SPECTs were performed 15 minutes after intravenous administration of 111 MBq 201Tl chloride. Regions of interest (ROI) were set up around tumor (T), and non-lesion (N) at the part of contralateral scalp at the height of the cerebellum. The ratios of mean counts in ROI of the tumor to those in non-lesion were measured as pre- and post-treatment T/N ratios (pre T/N, post T/N). Furthermore, reduction rate (RR) was obtained by calculating [(pre T/N - post T/N)/(pre T/N)] x 100%. Each parameter (pre T/N, post T/N, and RR) was compared to histopathological grade of surgical specimen based on the Oboshi and Shimosato classification (grade I-IV). RR showed significantly higher values in grade III and IV than in grade I and II (p=0.0008). In conclusion, semiquantitative assessment using Tl SPECT, especially calculating RR, is useful to evaluate the effectiveness of preoperative radiotherapy. (author)

172

Prognostic value of technetium-99m-labeled single-photon emission computerized tomography in the follow-up of patients after their first myocardial revascularization surgery  

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OBJECTIVE: To assess the prognostic value of Technetium-99m-labeled single-photon emission computerized tomography (SPECT) in the follow-up of patients who had undergone their first myocardial revascularization. METHODS: We carried out a retrospective study of 280 revascularized patients undergoing myocardial scintigraphy under stress (exercise or pharmacological stress with dipyridamole) and at rest according to a 2-day protocol. A set of clinical, stress electrocardiographic and scintigraph...

Santos Márcia Maria Sales dos; Cwajg Eduardo; Pantoja Mauricio da Rocha

2003-01-01

173

Early effects of gamma knife radiosurgery on brain metastases. Assessment by 201TlCl SPECT and 99mTc-DTPA-human serum albumin SPECT  

International Nuclear Information System (INIS)

Thallium-201 chloride (201TlCl) single photon emission computed tomography (SPECT) was used to determine tumor viability, and the early and delayed images of technetium-99m-diethylenetriaminepentaacetic acid-human serum albumin (99mTc-HSA-D) SPECT were used to assess tumor vascularity and permeability, respectively, in 17 patients with 18 brain metastases. SPECT was performed before, 1 week after, and 1 month after radiosurgery. The ratios of 201Tl and 99mTc-HSA-D uptake in a tumor were expressed as a ratio to uptake in the corresponding normal contralateral areas (uptake index). Magnetic resonance imaging with gadolinium was used to determine tumor volume. 201Tl index decreased significantly 1 week (p99mTc-HSA-D indices of early and delayed images obtained at 1 week after radiosurgery were not significantly different from the pretreatment values. However, both were significantly low (p<0.05) 1 month after radiosurgery. No change in tumor volume was detected 1 week following radiosurgery, but there wag a significant decrease (p<0.005) after 1 month. The reduction in tumor viability that occurs before the appearance of evidence of tumor shrinkage represents the early effect of radiosurgery on brain metastases. Reduction in tumor size, vascularity, and permeability occur subsequently. (author)

174

Myocardial metabolic imaging by means of fluorine-18 deoxyglucose/technetium-99m sestamibi dual-isotope single-photon emission tomography  

International Nuclear Information System (INIS)

It was the aim of the present work to develop and test FDG single-photon emission tomography (SPET) with the means of conventional nuclear medicine. The perfusion marker sestamibi (MIBI) was used together with the metabolic tracer FDG in dual-isotope acquisition. A conventional SPET camera was equipped with a 511-keV collimator and designed to operate with simultaneous four-channel acquisition. In this way, the scatter of 18F into the technetium-99m energy window could be taken into account by a novel method of scatter correction. Thirty patients with regional wall motion abnormalities at rest were investigated. The results of visual wall motion analysis by contrast cine-ventriculography in nine segments/heart were compared with the results of quantitative scintigraphy. The scintigraphic patterns of MIBI and FDG tracer accumulation were defined as normal, matched defects and perfusion-metabolism mismatches. Spatial resolution of the system was satisfactory, with a full width at half maximum (FWHM) of 15.2 mm for 18F and 14.0 mm for 99mTc, as measured by planar imaging in air at 5 cm distance from the collimator. Image quality allowed interpretation in all 30 patients. 88% of segments without relevant wall motion abnormalities presented normal scintigraphic results. Seventy-five akinetic segments showed mismatches in 27%, matched defects in 44% and normal perfusion in 29%. We conclude that FDG-MIBI dual-isotope SPET is technically feasiIBI dual-isotope SPET is technically feasible with the means of conventional nuclear medicine. Thus, the method is potentially available for widespread application in patient care and may represent an alternative to the 201Tl reinjection technique. (orig.)

175

A mechanism for myocardial uptake of /sup 201/Tl  

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Although the kinetics of Tl have been studied extensively the mechanisms governing its intracellular distribution in myocardium are not fully understood. One possibility is that Tl distributes within the interstitial and intracellular spaces according to the electrochemical gradients established by the cell membrane potential (?PSI). If so, the equilibrium concentrations C/sub I/ (intracellular) and C/sub O/ (interstitial) will obey the second law of thermodynamics as expressed by the Nernst Equations. To test this hypothesis the authors used a preparation of beating fetal mouse hearts in an organ culture medium. The measured concentration ratio (mouse heat to medium), R, was measured as a function of time and was fit to the model R=0.323[1+(K/sub I//K/sub O/)(1-EXP(-K/sub O/t)], where K/sub I/ and K/sub O/ are the inward and outward rate constants for transport across the cell membrane. At equilibrium, conservation of tracer mass ensures that C/sub I//C/sub O/=0.323 K/sub I//K/sub O/, where 0.323 is the ratio of interstitial to intracellular volume. In the control state the model estimate of the equilibrium membrane potential was -87 mV; whereas, for graded tissue injury the magnitude of the membrane potential decreased in proportion to the severity of injury. These data, obtained without the confounding effect of blood flow, show that intracellular Tl uptake in the fetal mouse heart can be interpreted in terms of membrane potential. The results of this work can in tential. The results of this work can in principle be extended to the use of radiolabeled molecules and ECT for in vivo measurement of regional membrane potential

176

Dose redistribution in exercise thallium-201 single photon emission computerized tomography represent residual ischemia in old myocardial infarction  

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To explore whether redistribution in infarct-related area in exercise thallium-201 single photon emission computerized tomography (Ex-Tl SPECT) represents residual ischemia, 100 patients with antero-septal old myocardial infarction (OMI) were studied. {Delta}% Tl-uptake, the index of the degree of redistribution was calculated as a difference of % Tl-uptake in infarct-related area between initial and delayed images. Lactate extraction ratio (LER), the index of the degree of regional myocardial ischemia was obtained from a difference of lactate concentration between aorta and great cardiac vein during atrial pacing stress test (from 90 to 150 bpm) undergone within a week after Ex-Tl SPECT. Each {Delta}% Tl-uptake of 41 patients with LER<0 (ischemic group) and 59 patients with LER>0 (non-ischemic group) was 12.7+-7.2 and 3.5+-4.6 (mean+-SD, p<0.01). Mild redistribution ({Delta}% Tl-uptake {le}10) in Ex-Tl SPECT does not necessarily represent residual ischemia, but high redistribution ({Delta}% Tl-uptake >10) represents evident residual ischemia in OMI (maximal value of {Delta}% Tl-uptake in non-ischemic group was 10). (author).

Naito, Johji; Yamamoto, Kazuhiro; Asada, Shinji (Osaka Police Hospital (Japan)) (and others)

1990-09-01

177

Clinical significance of reverse redistribution on thallium-201 single-photon emission computed tomography in patients with acute myocardial infarction  

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To determine the clinical significance of reverse redistribution (RR), resting thallium-201 myocardial single-photon emission computed tomography was performed once or twice in 80 patients in subacute phase (1 week to 2 months) of myocardial infarction. Thirty eight patients demonstrated RR on at least one study (group RR) and 32 a fixed defect only (group FD). Group RR had significantly smaller defects than group FD. Standardizing the relation of the severity of wall motion abnormality of left ventricle on echocardiogram with that of perfusion defect, in group RR wall motion abnormality in the acute and subacute phase reflected the defect of delayed image, while that in chronic phase, which was thought to reflect the viability of myocardium in the infarct region, reflected the defect of initial image. In serial thallium-201 studies, only the defect of delayed image of group RR improved on the second study, while the defect of initial image of group RR and defect of group FD did not improve. Wall motion of group RR improved with the disappearance of RR, and when RR remained, wall motion did not improve so much. We concluded that RR was thought to be demonstrated in viable myocardium with severe wall motion abnormality. (author)

178

Clinical evaluation of 201Tl-chloride scintigraphy for bone lesions  

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Clinical evaluation of 201Tl-chloride scintigraphy for bone lesions was examined in 66 patients by comparing with sup(99m)Tc-MDP scintigraphy. The abnormal accumulation of 201Tl was found in 43.9% of 57 patients with bone lesions, and that on sup(99m)Tc-MDP was 98.2%. The abnormal findings of 201Tl scintigraphy in cases with primary bone tumors were found in all cases with osteosarcomas and giant cell tumors. A case with recurrent giant cell tumor also had positive findings of 201Tl scanning. The sensitivity and specificity of 201Tl scanning for detecting bone metastases were 50% and 100%, and those of sup(99m)Tc-MDP scintigraphy were 100% and 54.2%, respectively. Positive images with 201Tl scintigraphy were obtained in several cases with metastatic bone tumors. In the cases with inflammatory bone diseases, no positive findings of 201Tl scanning were obtained, though in all of these cases sup(99m)Tc-MDP scintigraphic findings were positive. From these results, 201Tl scintigraphy for bone lesions is considered to be useful for the diagnosis of primary bone tumors and metastatic bone tumors. (author)

179

Recovery of 201Tl by ion exchange chromatography from proton bombarded thallium cyclotron targets  

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A method based on ion exchange chromatography is presented for the recovery of 201Tl and its precursor 201Pb from proton bombarded natural thallium cyclotron targets. After bombardment the target is dissolved in diluted nitric acid. Water, hydrazine and ammonium acetate are added to the solution and the lead radioisotopes separated from the thallium by cation exchange chromatography on a Bio-Rex 70 column. The sorbed lead radioisotopes are eluted with dilute nitric acid and the separation repeated on a second Bio-Rex 70 column. After elution of the remaining thallium the column is left for 32 hours and the 201Tl formed by decay of 201Pb is eluted with an ammonium acetate solution. The 201Tl eluate is acidified with a HNO3-HBr-Br2 mixture and the resulting solution is passed through an AG MP-1 anion exchanger column to remove any remaining lead isotopes. The 201Tl is eluted with a hydrazine solution, the eluate evaporated to dryness and the 201Tl finally dissolved in an appropriate solution to produce a 201TlCl solution suitable for medical use. A high quality 201Tl product is obtained containing ? 0.1 ?g of Tl/mCi (37 MBq) 201Tl. The radionuclidic impurities are less than the maximum values specified by the US Pharmacopoeia and the British Pharmacopoeia. (orig.)

180

Quantitative assessment of myocardial viability following coronary artery bypass grafting using exercise thallium-201 myocardial single photon emission computed tomography and left ventricular regional wall motion  

International Nuclear Information System (INIS)

Using exercise thallium-201 myocardial single photon emission computed tomography (SPECT) and % radial shortening (%RS), 58 patients were evaluated before and after coronary artery bypass grafting (CABG) to quantitatively assess myocardial viability and the effect of CABG. The patient was classified, according to redistribution pattern, as group I with only complete redistribution (20 cases) and group II with including incomplete redistribution (22 cases) and group III with no redistribution (16 cases). Group I was expected complete improvement of ischemic myocardium after CABG but regional left ventricular wall motion was unchanged (?i%RS: 142.5±54.7?138.4±39.6, ?a%RS: 201.2±51.1?238.2±68.2). Group II was expected to diminish ischemic size after CABG and left ventricular regional wall motion was significantly improved (?i%RS: 68.8±25.9?154.9±42.6 p<0.01, ?a%RS: 108.4±62.3?178.9±77.6, p<0.05). Group III was no significant change of ischemic size and left ventricular wall motion after CABG (?i%RS: 67.8±24.1?83.9±19.2, ?a%RS: 86.0±29.0?94.0±33.9). The present study suggests that quantitative assessment of myocardial viability using exercise thallium-201 myocardial SPECT and %radial shortening was useful method to determine the indication and to assess the effect of CABG. (author)

 
 
 
 
181

Quantification of myocardial infarct size by thallium-201 single-photon emission computed tomography: experimental validation in the dog  

International Nuclear Information System (INIS)

To evaluate the potential advantages of thallium-201 (201T1) single-photon emission computerized tomography (SPECT) to assess myocardial infarct size in the experimental animal, six normal dogs and 14 dogs with 6 to 8 hr closed-chest coronary occlusion (eight left anterior descending and six left circumflex) were studied. Ten minutes after intravenous administration of 2 mCi of 201T1, 30 projections were obtained over 1800. The dogs were killed and their hearts sliced and stained by triphenyl tetrazolium chloride (TTC). Pathologic infarct size was calculated for each slice and for the entire left ventricular myocardium as percent weight. Tomograms were quantified by automatically generating maximum-count circumferential profiles, which were compared with normal limit profiles derived from the six normal dogs. Tomographic infarct size was defined as the percentage of circumferential points falling below normal for each tomogram. SPECT and TTC infarct size on 71 slices correlated highly (mean +/- SD 27.9 +/- 23.4% and 26.7 +/- 25.3%, respectively; r = .93, p less than .001, SEE = 9.4%). To determine SPECT infarct size as percent total left ventricular myocardial weight, infarct sizes from each slice were added to one another after each was multiplied by a coefficient that reflected the contribution of that slice to the total left ventricular weight. SPECT and TTC infarct size for the entire left ventricle correlated closely (mean +/- SD 20.5 +/- 7.6% and 19.3 +/- 8.3%, respectively; r = .86, p less than .001, SEE = 4.5%). It is concluded that 201T1 SPECT is a valid method for the noninvasive assessment of experimental myocardial infarct size

182

Iodine-123-labelled fatty acids for myocardial single-photon emission tomography: current status and future perspectives  

International Nuclear Information System (INIS)

Renewed interest in the clinical use of iodine-123-labelled fatty acids is currently primarily focused on the use of iodine-123-labelled 15-(p-iodophenyl)pentadecanoic acid (IPPA) and ''modified'' fatty acid analogues such as 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) which show delayed myocardial clearance, thus permitting single-photon emission tomographic imaging. Interest in the use of BMIPP and similar agents results from the differences which have often been observed in various types of heart disease between regional myocardial uptake patterns of [123I]BMIPP and flow tracer distribution. Although the physiological basis is not completely understood, differences between regional fatty acid and flow tracer distribution may reflect alterations in important parameters of metabolism which can be useful for patient management or therapy planning. These tracers may also represent unique metabolic probes for correlation of energy substrate metabolism with regional myocardial viability. The two agents currently most widely used clinically are 123I-labelled IPPA and BMIPP. While [123I]IPPA is commercially available as a radiopharmaceutical in Europe (Cygne) and Canada (Nordion), multicenter trials are in progress in the United States as a prelude to approval for broad use. [123I]BMIPP was recently introduced as Cardiodine for commercial distribution in Japan (Nihon Medi-Physics, Inc.). [123I]BMIPP is alssics, Inc.). [123I]BMIPP is also being used in clinical studies on an institutional approval basis at several institutions in Europe and the United States. In this review, the development of a variety of radioiodinated fatty acids is discussed. The results of clinical trials with [123I]IPPA and [123I]BMIPP are discussed in detail, as are the future prospects for fatty acid imaging. (orig.)

183

Evaluation of dilated cardiomyopathy by stress Tl-201 myocardial single photon emission computed tomography (SPECT)  

International Nuclear Information System (INIS)

Stress Tl-201 myocardial SPECT was performed in 20 dilated cardiomyopathy (DCM) and 23 old myocardial infarction (OMI: ED volume ? 200 ml by left ventriculography = LVG) for non-invasive diagnosis of DCM. We assessed the perfusion abnormality of 5 segments (anterior-anterolateral, septal, apical, posterolateral, postero-inferior) in SPECT images in grades as follows; 0: normal, 1: mild low uptake, 2: severe low uptake, 3: complete defect. Thus, we defined the abnormal perfusion score (APS) as the summation of the grades in 5 segments. 1) Perfusion abnormality was found 85 % in DCM and 100 % in OMI by stress SPECT images. 2) Rare complete defect, abnormal perfusion segments under 3 and APS under 7 were characteristic findings in DCM, and could finally distinguish DCM from OMI with the finding of APS under 7 (18/20: 90 %) in stress images. 3) The perfusion abnormality in delayed images had a good relation with wall motion abnormality in OMI, but not DCM. 4) Redistribution was found only 3 cases with DCM (15 %) and 9 cases with OMI (39 %), but mild without 2 cases with OMI. 5) Inspite of exercise induced severe symptom and arrhythmia in some DCM cases, stress SPECT was efficient especially to rule out ischemic heart disease. Thus, we conclude that stress Tl-201 myocardial SPECT is useful method for the non-invasive differential diagnosis of DCM from ischemic heart disease, but wall motion abnormality has no good relation with perfusion abnormality. (author)

184

Gold-195m first-pass radionuclide ventriculography, thallium-201 single-photon emission CT, and 12-lead ECG stress testing as a combined procedure  

International Nuclear Information System (INIS)

Graded, sequential, rest/exercise, gold-195m, first-pass ventriculography and thallium-201 (Tl-201) single-photon emission computed tomography (SPECT) were performed simultaneously during a single, electrocardiograph-monitored, bicycle stress test in 24 individuals. The technical aspects and logistics involved in performing this combined radionuclide study are stressed in this preliminary report. Fourteen healthy volunteers each had a normal left ventricular ejection fraction and wall-motion response, along with normal T1-201 perfusion and washout, as determined by both visual and quantitative analysis of the tomographic sections. Each of ten patients with coronary artery disease had at least one abnormality of these parameters. The authors suggest that it is technically feasible to evaluate both cardiac function and myocardial perfusion simultaneously by combing Au-195m ventriculography and Tl-201 SPECT imaging into a single, noninvasive, diagnostic package

185

201Tl perfusion study of ''ischemic'' ulcers of the leg: prognostic ability compared with Doppler ultrasound  

International Nuclear Information System (INIS)

Thallium 201 perfusion analysis was compared with Doppler ultrasound as a means of determining the healing potential of an ischemic ulcer of the leg in 27 patients. The degree of hyperemia was determined by comparative point counting of the 201Tl distribution in and about the ulcer. Using established Doppler criteria and a hyperemia ratio greater than 1.5:1, ultrasound alone correctly predicted healing in 15 out of 23 cases and 201Tl in 20 out of 23. Ultrasound correctly predicted non-healing in 3 out of 6 cases, compared with 5 out of 6 for 201Tl. The positive predictive value of the 201Tl study was 63%, versus 27% for ultrasound, and the negative predictive value was 95% for 201Tl and 83% for ultrasound. The accuracy of 201Tl and ultrasound was 86% and 62%, respectively. This limited study suggests that 201Tl perfusion scanning is a useful noninvasive test of ulcer healing potential and may be more sensitive than Doppler ultrasound

186

The dobutamine stress Tl-201 myocardial single photon emission computed tomography for coronary artery stenosis caused by Kawasaki disease  

International Nuclear Information System (INIS)

Noninvasive cardiac imaging with pharmacologic stress Tl-201 single photon emission computed tomography (SPECT) as an alternative to exercise test is now getting popular for patients with Kawasaki disease. Dobutamine infusion produces hemodynamic change which is quite similar to exercise induced hemodynamic change. Material consisted of 17 patients (13 males, 4 females) with coronary occlusion or significant coronary stenosis (?75% diameter stenosis) caused by Kawasaki disease. After step-wise infusion of dobutamine up to 40 ?g/kg/min., quantitative analysis of Tl-201 SPECT was obtained. No patient had a symptomatic arrhythmia or severely stress-induced ischemia. The sensitivity and specificity of dobutamine induced perfusion defects were 65% (11 to 17) and 92% (1 of 13) respectively. The sensitivity was 87% (7 of 8) in patients with the left coronary artery lesions and 46% (6 of 13) in patients with the right coronary artery lesions. We conclude that a quantitative analysis of Tl-201 SPECT after step-wise infusion of dobutamine is a safe and clinically useful method for detection of stress-induced myocardial ischemia in coronary artery stenosis caused by Kawasaki disease. (author)

187

Myocardial sestamibi single-photon emission tomography: variations in reference values with gender, age and rest versus stress?  

International Nuclear Information System (INIS)

Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise 99mTc-sestamibi SPET with a 2-day protocol and 180 elliptical rotation. The normalized activity values of 99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in 99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary. (orig.). With 3 figs., 3 tabs

188

Dual radionuclide single-photon emission computed tomography in the prediction of further ischemic risk after acute myocardial infarction  

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To evaluate whether the findings of dual single-photon emission computed tomography (SPECT) with technetium-99m pyrophosphate (Tc-99m PPi) and thallium-201 were predictive of further cardiac events in their hospital course, we studied 130 patients recovering from acute myocardial infarction (AMI). Fifty-four patients showed overlapping of Tc-99m PPi and thallium-201 in the same location (overlap positive group), and 76 patients had no overlap (overlap negative group). Of the 130 patients, 36 (28%) had a cardiac event. In patients in the overlap positive group, the incidence of subsequent events was significantly higher than in patients in the overlap negative group (44% versus 16%; p<0.001). In the overlap positive group, the Tc-99m PPi uptake score and the number of overlap segments in patients with further events was significantly higher than those in patients without further events (10.2±5.1 versus 6.4±4.1, p<0.005 and 5.2±2.0 versus 3.3±1.3, p<0.001, respectively). These results suggest that patients who have a Tc-99m PPi and thallium-201 overlap negative scan can be candidates for early hospital discharge. In contrast, patients who have a greater number of overlap segments may require early catheterization and revascularization, so that simultaneous SPECT imaging Tc-99m PPi and thallium-201 might be useful for identifying patients with further ischemic risk after AMI in their hospital course. (author)

189

Leg arteritis exploration by quantitative muscle scintigraphy with 201Tl  

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Detection and localization of peripheral arterial disease was evaluated by an intravenous injection of 201Tl at peak exercise in 18 subjects and at rest in 6 patients. Images of the skull (S), thighs (T), knees (K), calves (C) and feet (F) were obtained at rest or after exercise and stored in a computer. Intraleg (T/K, T/C, T/F), and left to right interleg (TL/TR,...) count ratios were calculated. In addition, all patients were submitted to routine functional tests (walk perimeter, serial local arterial blood pressure measurement, Strandness test, venous occlusion plethysmography). Correlations between functional tests and the intra and interleg ratios were calculated. After exercise, there is a medium correlation between the tissular blood flow under hyperemia at the calf level and the T/C and C/K ratios. At the calf level a good correlation is obtained for CL/CR and the flux under hyperemia (r = 0.81, P 0.001). A ratio between the counting rates of limb segments after exercise and those of skull was established. The ratios T/S and C/S compared with the systolic pressure index of the most affected limb after a Strandness test give a correlation of 0.72 (P 0.02) for the thigh and of 0.86 (P 0.001) for the calf. For hyperemic flux, the correlation are 0.58 (P 0.005) with T/S and 0.75 (P 0.001) with C/S. In order to find the best quantitative scintigraphic index of the arterial illness, we compared the different ratio values with the distance walked. For T/S we found a relationship very close to a linear one and for C/S a less significant exponential one. Thus, quantitative scintigraphy using 201Tl appears as an accurate method to measure local muscular perfusion deficit in the cases of lower limb arterial disease.

Robert, J.; Thouvenot, P.; Schmidt, C.; Escanye, J.M.; Schmitt, J.

1984-10-01

190

Clinical usefulness of 201Tl-chloride scintigraphy for the diagnosis of bone metastases  

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Fifty-five patients with bone lesions underwent 201Tl-chloride (201Tl) scintigraphy to evaluate its findings and usefulness for the diagnosis of bone metastases. 201Tl scintigraphy was performed 15 minutes (early scan) and 2 hour (delayed scan) after iv injection of 5.55 MBq/kg of 201Tl-chloride. To evaluate the degree of tracer retention at the lesions, we calculated retention index after setting regions of interest in each lesion demonstrated tracer uptake in both early and delayed scans. Among 118 pathologically and/or clinically comfirmed bone metastases, 201Tl planar images disclosed 90 (76.3%) and 88 (74.6%) lesions on early and delayed scans, respectively. SPECT images were preferable for the evaluation of the lesions in the spine, thoracic cage and pelvis. Correlation of tumor size with findings on 201Tl images demonstrated 90.5% sensitivity for the metastases more than 7 cm3. No correlational difference was seen in the sensitivity depending on primary cancers. The overall retention index of bone metastases was -21.4±47.1. Bone metastases of pulmonary adenocarcinomas and small cell carcinomas demonstrated higher retention index than pulmonary squamous cell carcinomas and breast cancers. On 201Tl images, no abnormal tracer uptake was seen in benign lesions detected by 99mTc-hydroxymethylene diphosphonate (99mTc-HMDP) images except 5 lesions. The retentHMDP) images except 5 lesions. The retention index of the benign lesions demonstrated abnormal uptakes of -48.3±15.9 on 201Tl images, showing no significant difference between that of metastases. For vertebral compression fractures, abnormal tracer uptakes were demonstrated in 9 of the 12 pathologic fractures against 2 of the 10 benign ones. Those 2 benign fractures proved to be vertebral tuberculosis. The results suggest 201Tl scintigraphy can find out false positive lesions of 99mTc-HMDP scintigraphy and contribute to diagnosis of bone metastases with combination of other images. (author)

191

Myocardial imaging with thallium-201 for assessment of regional myocardial perfusion and viability after intracoronary thrombolytic therapy  

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Whereas coronary arteriography demonstrates success of reflow or recanalization after intracoronary thrombolysis, myocardial perfusion imaging with thallium-201 (201Tl) permits assessment of viability of reperfused myocytes. The initial distribution of 201Tl in the myocardium immediately after intravenous injection is the result of both blood flow delivery of the radionuclide to the heart and the extraction fraction for 201Tl. If 201Tl is administered during a period of coronary occlusion, a scintigraphic defect will be observed in the territory of the occluded vessel. If, subsequently, blood flow is restored, as with reperfusion, and cellular kinetics transport of 201Tl returns to normal, myocardial regions initially deprived of 201Tl will demonstrate delayed redistribution and the defect will tend to normalize within several hours. In a sustained coronary occlusion, the defect will persist after 201Tl injection. Specific imaging protocols that have been or can be used to assess thrombolytic therapy are reviewed. If intracoronary streptokinase infusion is associated with a substantial enhancement of perfusion and preservation of cellular integrity in the ischemic zone, delayed 201Tl images obtained several hours after intravenous injection of the radionuclide will demonstrate significantly more 201Tl activity than the images before reflow. Direct intracoronary injectionore reflow. Direct intracoronary injections of 201Tl down the infarct vessel have also been used to evaluate the benefit of thrombolytic therapy by the demonstration of increased 201Tl uptake after reperfusion in the ischemic zone. Finally, computer methods for subtracting serial images obtained after two separate intravenous 201Tl injections administered before and after streptokinase infusion might be used to derive a ''functional image'' of the ischemic region that would quantitatively be proportional to the amount of myocardial salvage achieved

192

201Tl to 67Ga crude uptake ratio as a prognostic indicator in primary lung cancer  

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Quantitative 201Tl and 67Ga scans were performed on 53 patients with primary lung cancer to measure 201Tl to 67Ga crude uptake ratio (CUR) by tumors. Based on the comparison of survival and actual survival time (AST) with CUR, we further evaluated whether or not CUR could predict the prognosis in lung cancer. A significant linear correlation was shown between CUR and AST (r = 0.704, p 201Tl to 67Ga crude uptake ratio (CUR) was a possible prognostic factor in primary lung cancer. (author)

193

Stress Tl-201 myocardial single photon emission computed tomography in diagnosing ischemic heart disease  

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Using a dual-head rotating gamma camera system, stress SPECT and conventional planar imaging were performed for 138 patients while they were examined by symptom-limited graded bicycle ergometer exercise. All patients underwent selective coronary arteriography and left ventriculography, and 93 had myocardial infarction (MI), 30 had effort angina (EA) and 15 were normal (control). Sensitivities for detecting IHD (SPECT: planar = 96 %: 89 %, p < 0.01), individual coronary arterial lesions (left anterior descending artery = LAD, 84 %: 68 %, p < 0.005; left circumflex artery = LCX, 60 %: 47 % NS; right coronary artery = RCA, 88 %: 69 %, p < 0.01), multivessel disease (= LAD + LCX and/or RCA, 53 %: 31 %, p < 0.025), and three vessel disease (60 %: 13 %, p < 0.005) were significantly higher by SPECT than by planar imaging. In addition, detection of ventricular aneurysms by SPECT was possible with a reasonably high sensitivity (94 %) and specificity (84 %). Signs of aneurysm included 1) an extensive anterior permanent defect, 2) a large left ventricular cavity, and 3) widening of the angle composed by the septal and lateral walls toward the apex in transaxial images. Sensitivity for detecting IHD was significantly lower in patients without MI (i.e., EA) than in patients with MI (MI: EA = 100 %: 83 %, p < 0.005). Sensitivity for detecting individual coronary arterial lesions was lower in the absence than in the presence of MI (LAD; 77 %: 87 %, LCX; 38 %: 68 %, RCA; 71 %: 90 %,%: 87 %, LCX; 38 %: 68 %, RCA; 71 %: 90 %, respectively), with multivessel disease than with single vessel disease, and with mild than with severe grade of stenosis. Sensitivity for detecting multivessel disease was lower in patients without MI than in those with MI (31 %: 61 %, respectively), and in anterior MI than in posteroinferior MI, or both MIs (36 %: 69 %: 100%, respectively). (J.P.N.)

194

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

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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. (author)

195

Clinical evaluation of 99mTc-CPI myocardial perfusion single photon emission computerized tomography in the diagnosis of coronary heart disease  

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Two normal subjects, 5 patients with old myocardial infarction (OMI) and 4 patients with angina pectoris were examined by rest single photon emission computerized tomography revealed that the right ventricular was not imaged, the left ventricular was well exposed in the normal subjects. All the 9 patients had defects in the left ventricle. comparison of SPECT with 99mTc-CPI with selective coronary arteriography (SCA), echocardiography (UCG), dynamic electrocardiography (DCG) and electrocardiographic (ECG)-exercise test in the diagnosis of myocardial ischemia or necrosis has demonstrated the former to be more significantly sensitive than the latter four. Good agreement between SPECT and SCA has been confirmed

196

Effect of post-myocardial infarction streptokinase (sk) therapy, on myocardial viability - evaluation with thallium-201 single photon emission computed tomography (TL-201 SPECT)  

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To evaluate the effect of post-myocardial infarction Streptokinase therapy on myocardial viability, employing Thallium-201 single photon emission computed tomography (TL-201 SPECT). Design: Retrospective, experimental study. Place and duration of study: The Nuclear Cardiology Department, Armed Forces Institute of Cardiology / National Institute of Heart Diseases, Rawalpindi, from 1 April, 2009 to 31 October, 2009. Patients and Methods: Male patients, who had suffered from acute myocardial infarction (AMI), in an area supplied by the left anterior descending (LAD) artery, had infarct-related electrocardiogram (ECG) changes and received or did not receive Streptokinase therapy, were included. Those with a normal ECG, or history of revascularisation, or non-ST elevation MI, or more than one MIs, were excluded. The patients were divided into groups 1 (who received Streptokinase) and 2 (who did not receive Streptokinase). Each group contained 42 patients and all underwent scintigraphic viability study through intravenous injection of 3.0 mCi (123 MBq) of TL-201, followed by rest-redistribution SPECT imaging on a dual head, dedicated cardiac gamma camera system (Philips Cardio MD). Emory's cardiac toolbox and AutoQUANT were used for data processing and quantitative estimation of viable myocardium. Empirical scores from 0 to 2 were assigned to each of the scans, in the order of increasing viability, and these were compared across the two groups. Result: Group 1 contained 42 two groups. Result: Group 1 contained 42 patients (age range = 38 to 80 years, mean = 53.98 +- 11.26 years), in whom empirical viability scoring was done. Score 0 was seen in 2 patients, score 1 was seen in 15 patients and score 2 was seen in 25 patients form this group. Group 2 also contained 42 patients (age range = 38 to 80 years, mean = 56.71 +- 9.05 years), in whom viability score of 0 was seen in 3 patients, score 1 was seen in 11 patients and score 2 was seen in 28 patients form this group. Age difference between the two groups was statistically insignificant (p = 0.223). The myocardial viability results analysed by 3 x 2 contingency table applying chi-square (X/sup 2/) test also showed no significant difference between groups 1 and 2 (p = 0.611). Conclusion: This study did not find any significant difference in myocardial viability - post-myocardial infarction - in patients who received or did not receive Streptokinase therapy. (author)

197

Relationship between availability of the collateral circulation and ischemic time for myocardial viability in patients with acute myocardial infarction. Assessment by technetium-99m tetrofosmin single photon emission computed tomography  

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Myocardial accumulation before reperfusion therapy of a radioactive tracer in the completely occluded region, conceivably reflects the viability of myocytes and degree of collateral circulation. To confirm this, the present study examined the relationship in the title. Subjects were 33 patients (F 7, M 26; average age 65 y) of the first 1-branch acute myocardial infarction and of TIMI (thrombolysis in myocardial infarction trial) grade 0 who recovered to TIMI 3 within 12 hr after attack: 99mTc-tetrofosmin, 740 MBq, was intravenously injected before reperfusion and just after which, SPECT imaging (TF-SPECT) was conducted with Toshiba E. CAM, and regional severity score index (RSSI) (0-3) was calculated. About 1 week later, to see the myocardial viability in the chronic phase, GITl (Glucose-Insulin-201Tl) (111 MBq) SPECT was performed 30 min after its injection to calculate RSSI as above, and the echocardiography with ALOKA Pro Sound SSD-4000 or SIEMENS Acuson SEQUOIA C256 was done to calculate the regional wall motion score index (RWMSI) (0-4). RWMSI was found significantly correlated with TF-RSSI, the group with the better collateral circulation (TF-RSSI, 1.9 or less) exhibited significantly lower GITl-RSSI and RWMSI, and correlation between the ischemic time and neither TF-RSSI, GITl-RSSI nor RWMSI was found. Thus under these conditions, the development of collateral vessels was found to have potential protective effects on myocardium independenrotective effects on myocardium independently on the ischemic time. (T.I.)

198

Myocardial metabolic, hemodynamic, and electrocardiographic significance of reversible thallium-201 abnormalities in hypertrophic cardiomyopathy  

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Exercise-induced abnormalities during thallium-201 scintigraphy that normalize at rest frequently occur in patients with hypertrophic cardiomyopathy. However, it is not known whether these abnormalities are indicative of myocardial ischemia. Fifty patients with hypertrophic cardiomyopathy underwent exercise 201Tl scintigraphy and, during the same week, measurement of myocardial lactate metabolism and hemodynamics during pacing stress. Thirty-seven patients (74%) had one or more 201Tl abnormalities that completely normalized after 3 hours of rest; 26 had regional myocardial 201Tl defects, and 26 had apparent left ventricular cavity dilatation with exercise, with 15 having coexistence of these abnormal findings. Of the 37 patients with reversible 201Tl abnormalities, 27 (73%) had metabolic evidence of myocardial ischemia during rapid atrial pacing compared with four of 13 patients (31%) with normal 201Tl scans (p less than 0.01). Eleven patients had apparent cavity dilatation as their only 201Tl abnormality; their mean postpacing left ventricular end-diastolic pressure was significantly higher than that of the 13 patients with normal 201Tl studies (33 +/- 5 versus 21 +/- 10 mm Hg, p less than 0.001). There was no correlation between the angiographic presence of systolic septal or epicardial coronary arterial compression and the presence or distribution of 201Tl abnormalities. Patientof 201Tl abnormalities. Patients with ischemic ST segment responses to exercise had an 80% prevalence rate of reversible 201Tl abnormalities and a 70% prevalence rate of pacing-induced ischemia. However, 69% of patients with nonischemic ST segment responses had reversible 201Tl abnormalities, and 55% had pacing-induced ischemia. Reversible 201Tl abnormalities during exercise stress are markers of myocardial ischemia in hypertrophic cardiomyopathy and most likely identify relatively underperfused myocardium

199

Detection of impaired fatty acid metabolism in right ventricular hypertrophy. Assessment by I-123 ?-methyl iodophenyl pentadecanoic acid (BMIPP) myocardial single-photon emission computed tomography  

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The subjects consisted of 6 patients with chronic obstructive pulmonary disease, 4 with primary pulmonary hypertension, 2 each with refractory pulmonary tuberculosis, tricuspid insufficiency, pulmonary embolism, 1 each with atrial septal defect, ventricular septal defect (Eisenmenger complex), Ebstein anomaly, and endocardial defect, and 7 healthy controls. SPECT imaging with Tl-201 (Tl) and I-123 BMIPP, and Tc-99m RBC first pass and gated blood pool scintigraphy were performed. Based on Tl planar images, the subjects were classified into 3 groups: 7 patients with no RV visualization (Group A), 11 with moderate RV visualization (Group B) and 9 with marked RV visualization (Group C). As a semi-quantitative evaluation by a myocardial SPECT, 3 regions in 3 representative short axial images were divided into 9 segments, each of which was graded from 0 to +3, and their sum was calculated as the RV score. The right ventricular ejection fraction (RVEF and the left ventricular ejection fraction were obtained by Tc-99m RBC cardiac scintigraphy. The groups with marked visualization of the right ventricle had lower RVEF, and there was a good correlation between the RVEF and the RV score with both a and BMIPP. Although a good correlation was demonstrated between the RV score with Tl and BMIPP in Groups A and B, in Group C, in which there was marked RV Tl visualization, the RV score with BMIPP was significantly smaller than with Tl. These findings suggest that impaired fatty acid findings suggest that impaired fatty acid metabolism may exist in severely hypertrophic right ventricle due to RV overload. (K.H.)

200

Non-invasive evaluation of myocardial reperfusion by transthoracic Doppler echocardiography and single-photon emission computed tomography in patients with anterior acute myocardial infarction  

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Full Text Available Abstract Background The study was designed to evaluate whether the preserved coronary flow reserve (CFR 72 hours after reperfused acute myocardial infarction (AMI is associated with less microvascular dysfunction and is predictive of left ventricular (LV functional recovery and the final infarct size at follow-up. Methods In our study, CFR was assessed by transthoracic Doppler echocardiography (TDE in 44 patients after the successful percutaneous coronary intervention during the acute AMI phase. CFR was correlated with contractile reserve assessed by low-dose dobutamine echocardiography and with the total perfusion defect measured by single-photon emission computed tomography 72 hours after reperfusion and at 5 months follow-up. The ROC analysis was performed to determine test sensitivity and specificity based on CFR. Categorical data were compared by an ?2 analysis, continuous variables were analysed with the independent Student's t test. In order to analyse correlation between CFR and the parameters of LV function and perfusion, the Pearson correlation analysis was conducted. The linear regression analysis was used to assess the relationship between CFR and myocardial contractility as well as the final infarct size. Results We estimated the CFR cut-off value of 1.75 as providing the maximal accuracy to distinguish between patients with preserved and impaired CFR during the acute AMI phase (sensitivity 91.7%, specificity 75%. Wall motion score index was better in the subgroup with preserved CFR as compared to the subgroup with reduced CFR: 1.74 (0.29 vs. 1.89 (0.17 (p Conclusion The early measurement of CFR by TDE can be of high value for the assessment of successful reperfusion in AMI and can be used to predict LV functional recovery, myocardial viability and the final infarct size.

Celutkiene Jelena

2011-05-01

 
 
 
 
201

Postoperative myocardial infarction documented by technetium pyrophosphate scan using single-photon emission computed tomography: Significance of intraoperative myocardial ischemia and hemodynamic control  

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The aim of this prospective study was to document postoperative myocardial infarction (PMI) by technetium pyrophosphate scan using single-photon emission computed tomography (TcPPi-SPECT) in 28 patients undergoing elective coronary bypass grafting (CABG). The relationships of intraoperative electrocardiographic myocardial ischemia, hemodynamic responses, and pharmacological requirements to this incidence of PMI were correlated. Radionuclide cardioangiography and TcPPi-SPECT were performed 24 h preoperatively and 48 h postoperatively. A standard high-dose fentanyl anesthetic protocol was used. Twenty-five percent of elective CABG patients were complicated with PMI, as documented by TcPPi-SPECT with an infarcted mass of 38.0 +/- 5.5 g. No significant difference in demographic, preoperative right and left ventricular function, number of coronary vessels grafted, or aortic cross-clamp time was observed between the PMI and non-PMI groups. The distribution of patients using preoperative beta-adrenergic blocking drugs or calcium channel blocking drugs was found to have no correlation with the outcome of PMI. As well, no significant differences in hemodynamic changes or pharmacological requirements were observed in the PMI and non-PMI groups during prebypass or postbypass periods, indicating careful intraoperative control of hemodynamic indices did not prevent the outcome of PMI in these patients. However, the incidence of prebypass ischemia was 39.3% and significantly correlated with the outcome of positive TcPPi-SPECT, denoting a 3.9-fold increased risk of developing PMI. Prebypass ischemic changes in leads II and V5 were shown to correlate with increased CPK-MB release (P less than 0.05) and tends to occur more frequently with lateral myocardial infarction.

Cheng, D.C.; Chung, F.; Burns, R.J.; Houston, P.L.; Feindel, C.M. (Toronto Hospital, Ontario (Canada))

1989-12-01

202

Postoperative myocardial infarction documented by technetium pyrophosphate scan using single-photon emission computed tomography: Significance of intraoperative myocardial ischemia and hemodynamic control  

International Nuclear Information System (INIS)

The aim of this prospective study was to document postoperative myocardial infarction (PMI) by technetium pyrophosphate scan using single-photon emission computed tomography (TcPPi-SPECT) in 28 patients undergoing elective coronary bypass grafting (CABG). The relationships of intraoperative electrocardiographic myocardial ischemia, hemodynamic responses, and pharmacological requirements to this incidence of PMI were correlated. Radionuclide cardioangiography and TcPPi-SPECT were performed 24 h preoperatively and 48 h postoperatively. A standard high-dose fentanyl anesthetic protocol was used. Twenty-five percent of elective CABG patients were complicated with PMI, as documented by TcPPi-SPECT with an infarcted mass of 38.0 +/- 5.5 g. No significant difference in demographic, preoperative right and left ventricular function, number of coronary vessels grafted, or aortic cross-clamp time was observed between the PMI and non-PMI groups. The distribution of patients using preoperative beta-adrenergic blocking drugs or calcium channel blocking drugs was found to have no correlation with the outcome of PMI. As well, no significant differences in hemodynamic changes or pharmacological requirements were observed in the PMI and non-PMI groups during prebypass or postbypass periods, indicating careful intraoperative control of hemodynamic indices did not prevent the outcome of PMI in these patients. However, the incidence of prebypass ischemia was 39.3% and significantly correlschemia was 39.3% and significantly correlated with the outcome of positive TcPPi-SPECT, denoting a 3.9-fold increased risk of developing PMI. Prebypass ischemic changes in leads II and V5 were shown to correlate with increased CPK-MB release (P less than 0.05) and tends to occur more frequently with lateral myocardial infarction

203

Comparative evaluation of some analyses of stress-redistribution thallium-201 myocardial SPECT for myocardial ischemia  

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Stress-redistribution thallium-201 (201Tl) myocardial single photon emission CT was performed in 55 patients with effort angina and 10 normal subjects. Visual interpretation and some quantitative expressions, which were maximum-count circumferential profile for myocardial distribution of 201Tl, segmental washout rate and each Bull's eye display, were analyzed to evaluate detectability for the territories of stenotic coronary arteries. The sensitivity of the visual method for detection of disease in LAD and RCA was fairly good and the specificity in each of the coronary artery was the highest in every analyses. However, the sensitivity for LCX and detectability in patient with multiple vessel disease were low. Accuracies of circumferential profile analysis and two Bull's eye display were equal or low as compared with visual method. Sensitivity of segmental washout rate was the highest value in every analyses and showed good results even in the patient with LCX lesion or multiple vessel disease. Washout rate score, which was calculated as the area between the washout rate profile curve and normal lower limits in the abnormal region, correlated well with severity of % coronary artery lumen diameter reduction. So we conclude that the visual method in combination with washout rate analysis is useful diagnostic method for detecting and evaluating patient with effort angina. (author)

204

Clinical evaluation of 201Tl-chloride scintigraphy for breast tumors  

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Fifty-two patients with breast tumors were scintigraphed with 201Tl-chloride. Each one was given a histological diagnosis after surgery or excisional biopsy. In 39 cases of primary breast cancer, 27 cases (69.2 %) showed a positive figure by 201Tl-chloride scintigraphy. In five cases of local recurrent breast cancer, four cases (80 %) showed a positive figure. In examining each histological type of primary breast cancer, in 10 cases of papillotubular carcinoma, seven (70 %) were positive with 201Tl-chloride. In 20 patients with medullary tubular carcinoma, 17 cases (85 %) revealed a positive figure. In nine cases of scirrhous carcinoma, only three cases (33.3 %) were positive. Some cases showed an accumulation in the metastatic lymph nodes of the axilla with 201Tl-chloride. In three cases of phyllodes tumor, two cases (66.7 %) were positive. On the other hand, all cases of benign breast tumors showed a negative figure by 201Tl-chloride scintigraphy. As to the uptake ratio of 201Tl-chloride into the breast carcinoma tissue, it was observed that papillotubular carcinoma absorbed 5.8 times as much as normal mammary gland tissue, medullary tubular carcinoma absorbed 4.7 times as much, scirrhous carcinoma absorbed 3.3 times as much as normal mammary gland tissue. In recurrent breast cancer, 201Tl-chloride scintigraphy is a useful procedure in determining the malignant area and in judging the effeche malignant area and in judging the effect of treatment. From the above mentioned results, it was concluded that 201Tl-chloride has specific affinity for malignant breast tumors and it is also very useful tumor-seeking agent to detect the early recurrent breast cancer. (author)

205

201Tl scintigraphic evaluation of tumor mass and viability of bone and soft-tissue tumors  

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To characterize 201Tl uptake in patients with bone and soft-tissue tumor, we studied 49 patients with surgically proven tumors and one patient with a tumor diagnosed arteriographically. In 37 of our 50 patients, the tumor was evaluated with 201Tl and arteriography. Moreover, in 14 of patients with pre-operative chemotherapy, pathologic changes were graded on the basis of percent tumor necrosis as defined histologically. The percent tumor necrosis histologically was compared with changes in the scintigraphic and conventional angiographic studies. Radiologic comparisons demonstrated a high degree of correlation with images of 201Tl and both arterial and blood pool phase of 99mTc-HMDP. Ninety-six percent of 28 malignant tumors had positive 201Tl uptake. None of the patients showed any thallium accumulation in the soft tissues or skeleton adjacent to the lesion. Activity of 201Tl was mainly dependent upon a tumor blood flow and a vascular density. In of 14 cases with the preoperative chemotherapeutic treatment, 201Tl scintigraphic changes showed concordance with % tumor necrosis. Thallium-201 was superior to 99mTc-HMDP in predicting tumor response to chemotherapy. Interestingly, delayed images of 99mTc-HMDP of 5 responders with >90% tumor necrosis showed decreased uptake in the adjacent bone to the tumor mass lesions. It seems to be quite all right to consider that a major dquite all right to consider that a major determinant of 201Tl uptake is intratumoral angiogenecity, which is closely connected with tumor viability. Therefore, 201Tl is a sensitive radiopharmaceutical for detection of vascular rich bone and soft-tissue tumors, and appears to be a simple and an accurate test for evaluating the response to specific therapeutic regimens of malignant bone and soft-tissue tumors. (author)

206

The evaluation of 201TlCl for thyroid imaging agent  

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The usefulness of 201TlCl for thyroid imaging agent was evaluated experimentally and clinically. 1. In Wistar rat, 201TlCl accumulation was greatest in the kidney, followed by thyroid, lung, myocardium, duodenum, skeletal muscle, liver and blood in order mentioned. 2. In the rat follicular cells, accumulation was increased with mercazole or TSH administration and decreased with T3 3. Linear correlation was constant between the accumulation of 42KCl and 201TlCl in the tissues of normal and TSH, mercazole or T3 administered rats as well as in implanted cancer tissues. 4. 201TlCl showed a higher affinity in the rapid growing adenocarcinoma 755 of the mouse than in the slow growing C5760. 5. Clinically 132 patients with nodular goiter were studied by imaging with sup(99m)TcO4- of Na131I followed with 201TlCl. Accumulation was observed in the corresponding nodular area in 85% of cancer, 60% of adenoma, 42% of adenomatous goiter and 0% of cyst. In general the hyperplastic solid lesion presented a positive image, while the degenerative or cystic lesion, a negative image. 6. 201TlCl was also accumulated in the regional lymphnode metastases. 7. Tumor to normal ratio was studied with the surgical specimens. Tumor to normal ratio of cancer was demonstrated to be higher than that of adenoma. (author)

207

Technetium-99m pyrophosphate/thallium-201 dual-isotope SPECT imaging predicts reperfusion injury in patients with acute myocardial infarction after reperfusion  

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Microcirculatory failure after reperfusion is clinically indicated to cause reperfusion injury whereas excessive intracellular calcium ion overload is experimentally proved as a key mechanism of reperfusion injury. We hypothesized that technetium-99m ({sup 99m}Tc) pyrophosphate (Tc-PYP) uptake in injured but viable infarct-related myocardium with preserved myocardial perfusion after reperfusion estimated by thallium-201 ({sup 201}Tl) uptake would be associated with final functional recovery. Dual-isotope Tc-PYP/{sup 201}Tl single-photon emission computed tomography (SPECT) was performed 2 days after successful reperfusion therapy in patients with first acute myocardial infarction, and 50 patients (63 {+-} 13 years old, female 22%) with preserved {sup 201}Tl uptakes of {>=}50% in reperfused myocardium was followed for 1 month. Tc-PYP uptake was assessed as the heart-to-sternum (H/S) ratio. Two-dimensional echocardiography was also performed 2 days and 1 month after reperfusion to evaluate functional recovery. High Tc-PYP uptake, defined as the H/S ratio {>=}0.81, was predictive of chronic phase no functional recovery (73.7% in 14 of 19 patients with high uptake vs 16.1% in five of 31 patients without those, p < 0.0001). After adjustment for potential confounding variables, including electrocardiographic persistent ST segment elevation at 1 h after reperfusion, high Tc-PYP uptake remained independently predictive of no functional recovery with odds ratio of 8.7 (95% confidential interval = 2 to 38.7; p = 0.005). High Tc-PYP uptake in reperfused but viable infarct-related myocardium was a powerful predictor of no functional recovery, which may reflect excessive intracellular calcium ion overload caused by reperfusion injury. Tc-PYP/{sup 201}Tl dual-isotope SPECT imaging can provide prognostic information after reperfusion. (orig.)

Akutsu, Yasushi; Kaneko, Kyouichi; Kodama, Yusuke; Li, Hui-Ling; Nishimura, Hideki; Hamazaki, Yuji; Kobayashi, Youichi [Showa University School of Medicine, Division of Cardiology, Department of Medicine, Tokyo (Japan); Suyama, Jumpei; Shinozuka, Akira; Gokan, Takehiko [Showa University School of Medicine, Department of Radiology, Tokyo (Japan)

2009-02-15

208

Sodium bicarbonate-augmented stress thallium myocardial scintigraphy  

International Nuclear Information System (INIS)

It is well known that sodium bicarbonate in pharmacological doses induces transient alkalosis, causing intracellular transport of serum potassium. The aims of this study were (a) to investigate whether, in humans, myocardial thallium-201 uptake can be augmented by pretreatment with a single bolus of sodium bicarbonate at a pharmacological dose, (b) to verify general safety aspects of the intervention and (c) to evaluate the clinical implications of augmentation of 201Tl uptake, if any. Routine exercise myocardial scintigraphy was performed twice in eight adult volunteers (five normal and three abnormal), once without intervention and the second time (within a week) following intravenous administration of sodium bicarbonate (88 mEq in 50 ml) as a slow bolus 1 h prior to the injection of 201Tl. Conventional myocardial thallium study was compared with sodium bicarbonate interventional myocardial scintigraphy with respect to myocardial uptake (counts per minute per mCi injected dose), washout patterns in normal and abnormal myocardial segments, and overall clinical interpretation based on planar and single-photon emission tomographic (SPET) images. All patients remained asymptomatic after the intervention. A mean increase of 53% in myocardial uptake of thallium was noted in post-exercise acquisitions after the intervention, confirming uptake of the tracer via the potassium-hydrogen pump and its augmentation by transient alkalosis. The washout patterny transient alkalosis. The washout pattern remained unchanged. The visual quality of planar and SPET images improved significantly after the intervention. Out of the five abnormal myocardial segments identified in three cases, four showed significant filling-in after the intervention, causing the diagnosis to be upgraded from ''partial scar'' to ''ischaemia'', or from ''ischaemia'' to ''normal''. The overall scan impression changed in two out of three such cases. Sodium bicarbonate augmentation may have significant implications for stress-thallium scintigraphy and may be a new parameter for defining myocardial viability. (orig.)

209

Development of [201Tl](IIIOxinate complex for cell labeling  

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Full Text Available Introduction: Due to interesting physical properties and wide availability of thallium-201 as a SPECT radionuclide, the incorporation of this nuclide into 8-hydroxyquinoline for cell labeling was targeted. Methods: Thallium-201 (T1/2=3.04 d in Tl+ form was converted to Tl3+ cation in presence of O3/6M HCl and di-isopropyl ether, controlled by RTLC/gel electrophoresis The final evaporated activity reacted with ethanolic 8-hydroxy-quinoline (oxine solution in normal saline to yield [201Tl](IIIoxinate at room temperature after 0.5 h, followed by solid phase extraction/purification using C18 Sep-Pak column Results: A radiochemical yield of more than 95% was obtained. Radiochemical purity of 92% was obtained using RTLC (>90% using HPLC with specific activity of about 820 GBq/mmol. The tracer was stable in the final product and in presence of human serum at 37°C up to 6h. The partition coefficient of lopP=5.5 was obtained. The labeled compound was used in red blood cell (RBC labeling. The cell uptake ratio was determined at 37°C up to 3 hours. Conclusion: The radiolabeled compound used in this study is a very inexpensive agent for use in cell labeling studies in biology, medicine and various research areas.  

Amir Hakimi

2010-10-01

210

The progress of assessment of myocardial viability by delayed-enhanced magnetic resonance imaging and positron emission tomography and single-photon emission computed tomography  

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Coronary artery disease (CAD)is one of the most common diseases that results in the different degree of myocardial damage. Thus, only viable myocardium in patients can get benefit from the myocardial revascularization. The accurate differentiation of viable and nonviable myocardium is crucial for therapy planning in patients with coronary artery disease and left ventricular dysfunction. Clinically, traditional techniques such as echocardiography, positron emission tomography, and single photon emission computed tomography have established roles. With the recent MRI technical developments allowing for a combined assessment of perfusion and irreversible damage with late enhancement imaging, MRI will now play a major role in the assessment of myocardial viability. Through the technique of delayed-enhancement MRI (DE-MRI), viable and infarcted myocardium can be simultaneously identified in a manner that closely correlates with histopathology findings. (authors)

211

Detection of impaired fatty acid metabolism in right ventricular hypertrophy: assessment by I-123 beta-methyl iodophenyl pentadecanoic acid (BMIPP) myocardial single-photon emission computed tomography.  

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Fatty acid metabolism has been reported to be impaired earlier than myocardial blood flow in left ventricular hypertrophic myocardium, e.g., in hypertrophic cardiomyopathy or hypertensive heart disease. The purpose of this study was to determine whether impaired fatty acid metabolism also occurs in right ventricular (RV) hypertrophy. The subjects consisted of 6 patients with chronic obstructive pulmonary disease, 4 with primary pulmonary hypertension, 2 each with refractory pulmonary tuberculosis, tricuspid insufficiency, pulmonary embolism, 1 each with atrial septal defect, ventricular septal defect (Eisenmenger complex), Ebstein anomaly, and endocardial defect, and 7 healthy controls. SPECT imaging with Tl-201 (Tl) and I-123 beta-methyliodophenyl pentadecanoic acid (BMIPP), and Tc-99m RBC first pass and gated blood pool scintigraphy were performed. Based on Tl planar images, the subjects were classified into 3 groups: 7 patients with no RV visualization (Group A), 11 with moderate RV visualization (Group B) and 9 with marked RV visualization (Group C). As a semi-quantitative evaluation by Tl myocardial SPECT, 3 regions in 3 representative short axial images were divided into 9 segments, each of which was graded from 0 to +3, and their sum was calculated as the RV score. The right ventricular ejection fraction (RVEF) and the left ventricular ejection fraction were obtained by Tc-99m RBC cardiac scintigraphy. The groups with marked visualization of the right ventricle had lower RVEF (p correlation between the RVEF and the RV score with both Tl and BMIPP (Tl: r = -0.79, BMIPP: r = -0.70). Although a good correlation was demonstrated between the RV score with Tl and BMIPP in Groups A and B (r = 0.86, p < 0.001), in Group C, in which there was marked RV T1 visualization, the RV score with BMIPP was significantly smaller than with Tl (BMIPP vs. Tl: 11.5 +/- 3.7 vs. 16.4 +/- 3.8, p < 0.01). These findings suggest that impaired fatty acid metabolism may exist in severely hypertrophic right ventricle due to RV overload. PMID:9310169

Kim, Y; Goto, H; Kobayashi, K; Sawada, Y; Miyake, Y; Fujiwara, G; Chiba, H; Okada, T; Nishimura, T

1997-08-01

212

Transient QT interval prolongation with inverted T waves indicates myocardial salvage on dual radionuclide single-photon emission computed tomography in acute anterior myocardial infarction  

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In patients with acute myocardial infarction (AMI), transient QT interval prolongation with a prominent negative T wave is frequently observed in cases of early spontaneous reperfusion and often indicates a good prognosis. Additionally, in nuclear cardiac imaging, technetium-99m/thallium-201 overlap on dual single-photon emission computed tomography (dual SPECT) in AMI patients indicates the presence of viable myocardium and early recanalization. To elucidate the clinical significance of this transient QT interval prolongation, 34 patients (64{+-}8 years) admitted within 24 h of the onset of anterior AMI were enrolled and classified into 2 groups according to the presence (group A, n=24) or absence (group B, n=10) of scintigraphic overlap on simultaneous dual SPECT imaging. The maximal QTc interval was 0.59{+-}0.06 s in group A and 0.52{+-}0.06 s in group B (p<0.01). The peak creatine kinase was lower in group A (2650{+-}2160 IU/L) than in group B (3490{+-}2060 IU/L). The left ventricular ejection fraction (LVEF) at discharge was 62{+-}11% in group A and 49{+-}14% in group B (p<0.01). The scintigraphic overlap group had a smaller infarct and better LVEF, which suggests that the QT interval prolongation that appears transiently in the acute phase of AMI indicates scintigraphically the presence of salvaged myocardium. (author)

Obayashi, Tohru; Tokunaga, Takeshi; Iiizumi, Tomohiro; Shiigai, Tatsuo [Toride Kyodo General Hospital, Ibaraki (Japan); Hiroe, Michiaki; Marumo, Fumiaki

2001-01-01

213

Transient QT interval prolongation with inverted T waves indicates myocardial salvage on dual radionuclide single-photon emission computed tomography in acute anterior myocardial infarction  

International Nuclear Information System (INIS)

In patients with acute myocardial infarction (AMI), transient QT interval prolongation with a prominent negative T wave is frequently observed in cases of early spontaneous reperfusion and often indicates a good prognosis. Additionally, in nuclear cardiac imaging, technetium-99m/thallium-201 overlap on dual single-photon emission computed tomography (dual SPECT) in AMI patients indicates the presence of viable myocardium and early recanalization. To elucidate the clinical significance of this transient QT interval prolongation, 34 patients (64±8 years) admitted within 24 h of the onset of anterior AMI were enrolled and classified into 2 groups according to the presence (group A, n=24) or absence (group B, n=10) of scintigraphic overlap on simultaneous dual SPECT imaging. The maximal QTc interval was 0.59±0.06 s in group A and 0.52±0.06 s in group B (p<0.01). The peak creatine kinase was lower in group A (2650±2160 IU/L) than in group B (3490±2060 IU/L). The left ventricular ejection fraction (LVEF) at discharge was 62±11% in group A and 49±14% in group B (p<0.01). The scintigraphic overlap group had a smaller infarct and better LVEF, which suggests that the QT interval prolongation that appears transiently in the acute phase of AMI indicates scintigraphically the presence of salvaged myocardium. (author)

214

Stress 201Tl-scintigraphy of the myocardium - comparison with veloergometry and selective coronary arteriography in patients with chronic ischeemic heart disease  

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The study has been carried out on 53 patients with complaints of pain with anterior thoracal localization, clinically diagnosed as stable angina pectoris at mild physical efforts; 31 of the patients had a case history of passed myocardial infarction. All patients have been subjected to right-and left-side cardiac catheterization, left ventricular ventriculography and standard selective coronary arteriography 3 to 20 days before or after stress scintigraphy (SS) with 201Tl-chloride. SS is carried out on a static veloergometer by stepwise loading; every 6 min a registration of the 6 thorax ECG-deviations is made and the arterial pressure is mesured. 201Tl-chloride (74 MBk) is injected at the pick of the physical burden. The myocardial perfusion is visualized on 'Nuclear Ohio' gamma camera with a parallel collimator in 3 projections in the course of 6 min for each projection, which allows to evaluate the perfusion of 9 segments of the myocardium. Two hours after the physical loading the myocardial perfusion at rest is studied by the same method. The comparative study shows a considerable advantage of the Tl-SS compared to veloergometry of patients with insignificant haemodynamic coronary stenosis: it allows a precise evaluation of the myocardial perfusion in cases when the appraisal of ECG-changes after a physical loading is difficult. 3 tabs., 5 refs

215

Clinical value of 201Tl lung/heart ratio during exercise in hypertensive patients with coronary artery disease  

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Objective: The purpose of the study was to evaluate the relationship between 201Tl lung/heart ratio during exercise and left ventricular diastolic function and its diagnostic value on severity of coronary artery disease. Methods: One hundred and two patients with documented coronary artery disease were divided into three groups, including no hypertension, hypertension without or with left ventricular hypertrophy groups. Exercise/delay 201Tl myocardial perfusion tomography was performed on all patients included. Lung/heart ratio was defined on the anterior planar image obtained during exercise tomography. Results: The lung/heart ratios during exercise in no hypertension (0.43 +- 0.09, P0.05). The lung/heart ratios of multi-vessel disease subgroup in no hypertension (0.46 +- 0.10 vs 0.40 +- 0.09, P0.05). When lung/heart ratio was?0.45, the sensitivities for predicting t0.45, the sensitivities for predicting the presence of multi-vessel disease were 82%, 90%, 40% and specificities were 75%, 75%, 45%, respectively, in no hypertension, hypertension without and with hypertrophy groups. In no hypertension (r=0.402, P0.05). In no hypertension (r=-0.413, P<0.01), hypertension without (r=-0.662, P<0.01) and with hypertrophy groups (r=-0.408, P<0.05), lung/heart ratios all showed a significant reverse correlation with correspondent E/A ratios. Conclusions: The exercise lung/heart ratios has a better diagnostic value for multi-vessel disease and left ventricular diastolic function abnormalities of coronary artery disease with or without hypertension, but not for multi-vessel disease in hypertension patients complicated with myocardial hypertrophy

216

Prognostic value of technetium-99m-labeled single-photon emission computerized tomography in the follow-up of patients after their first myocardial revascularization surgery  

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Full Text Available OBJECTIVE: To assess the prognostic value of Technetium-99m-labeled single-photon emission computerized tomography (SPECT in the follow-up of patients who had undergone their first myocardial revascularization. METHODS: We carried out a retrospective study of 280 revascularized patients undergoing myocardial scintigraphy under stress (exercise or pharmacological stress with dipyridamole and at rest according to a 2-day protocol. A set of clinical, stress electrocardiographic and scintigraphic variables was assessed. Cardiac events were classified as "major" (death, infarction, unstable angina and "any" (major event or coronary angioplasty or new myocardial revascularization surgery. RESULTS: Thirty-six major events occurred as follows: 3 deaths, 11 infarctions, and 22 unstable anginas. In regard to any event, 22 angioplasties and 7 new surgeries occurred in addition to major events, resulting a total of 65 events. The sensitivity of scintigraphy in prognosticating a major event or any event was, respectively, 55% and 58%, showing a negative predictive value of 90% and 83%, respectively. Diabetes mellitus, inconclusive stress electrocardiography, and a scintigraphic visualization of left ventricular enlargement were significant variables for the occurrence of a major event. On multivariate analysis, abnormal myocardial scintigraphy was a predictor of any event. CONCLUSION: Myocardial perfusion tomography with Technetium-99m may be used to identify high-risk patients after their first myocardial revascularization surgery.

Santos Márcia Maria Sales dos

2003-01-01

217

Quantification of myocardial infarction: a comparison of single photon-emission computed tomography with pyrophosphate to serial plasma MB-creatine kinase measurements  

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Single photon-emission computed tomography (SPECT) with /sup 99m/Tc-pyrophosphate (PPi) has been shown to estimate size of myocardial infarction accurately in animals. The authors tested the hypothesis that SPECT with /sup /sup 99m//Tc-PPi and blood pool subtraction can provide prompt and accurate estimates of size of myocardial infarction in patients. SPECT estimates are potentially available early after the onset of infarction and should correlate with estimates of infarct size calculated from serial measurements of plasma MB-creatine kinase (CK) activity. Thirty-three patients with acute myocardial infarction and 16 control patients without acute myocardial infarction were studied. Eleven of the patients had transmural anterior myocardial infarction, 16 had transmural inferior myocardial infarction, and six had nontransmural myocardial infarction. SPECT was performed with a commercially available rotating gamma camera. Identical projection images of the distribution of 99mTc-PPi and the ungated cardiac blood pool were acquired sequentially over 180 degrees. Reconstructed sections were color coded and superimposed for purposes of localization of infarct. Areas of increased PPi uptake within myocardial infarcts were thresholded at 65% of peak activity. The blood pool was thresholded at 50% and subtracted to determine the endocardial border for the left ventricle. Myocardial infarcts ranged in size from 1 to 126 gram equivalents (geq) MB-CK. The correlation of MB-CK ets (geq) MB-CK. The correlation of MB-CK estimates of size of infarct with size determined by SPECT (both in geq) was good (r = .89 with a regression line of y = 13.1 + 1.5x)

218

Evaluation of thallium-201 washout in patients with ischemic heart disease using ring-type single photon emission CT  

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With the emergence of single photon emission computed tomography (SPECT), thallium-201 (Tl) myocardial scanning has become the important diagnostic procedure of choice for ischemic heart disease; however, clinical and diagnostic aspects still remain unclear. The present study explored kinetics of Tl within the myocardium using ring-type SPECT that allows rapid sequential scanning. Three groups containing five patients with effort angina pectoris (EAP), old myocardial infarction (OMI), or chest pain syndrome (CPS), were scanned during exercise five times at five min intervals after injection of 2.5 - 4.0 mCi of Tl, and subsequently scanned at one, two, and three hr later. Time-activity curves and washout rates in five regions of interest were examined. At 30 min, washout rate was 10 % in the EAP and OMI groups and 0.2 % in the CPS group, showing significant difference between the former two groups and the latter group. This implies that ring-type SPECT may play an important role in elucidating the mechanism of Tl washout and myocardial blood flow, although it has still disadvantages of limited transaxial three scans and inability to correct scattered rays. (Namekawa, K.)

219

Does myocardial thallium-201 SPECT combined with electron beam computed tomography improve the detectability of coronary artery disease? Comparative study of diagnostic accuracy  

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The aim of this study is to evaluate the diagnostic accuracy of myocardial 201Tl SPECT combined with EBT for detecting CAD. The study was based on 34 patients with suspected CAD, who had EBT and myocardial 201Tl SPECT. The CAD was diagnosed by the findings of coronary arteriography. Sensitivity, specificity and accuracy of EBT, myocardial 201Tl SPECT and the combined diagnosis on a per vessel basis and a per-patient basis were studied. The sensitivity for detecting CAD of myocardial 201Tl SPECT, EBT and the combined diagnosis was 85%, 77%, and 62%, respectively. No significant difference in the accuracy of myocardial 201Tl SPECT, EBT and the combined diagnosis was observed on a patient basis and per vessel basis. In the over 70 yr age subgroup, the sensitivity and accuracy of EBT for detecting LAD lesion were significantly superior to those of myocardial 201Tl SPECT. Regardless of age-based subgroups and gender, the combined diagnosis did not contribute to an improvement in diagnostic accuracy. Although the sensitivity of EBT for detecting LAD lesion in patients over 70 yr of age was significantly higher than that of myocardial 201Tl SPECT, in the detectability of CAD, combined use of myocardial 201Tl SPECT and EBT offers no improvement. (author)

220

Preoperative diagnosis of nodular thyroid tumor by delayed scintigraphy using 201TlCl  

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Thallous chloride-201Tl [201TlCl] tends to readily concentrate in thyroid nodules. Since 1984, we have performed xerography, ultrasonography and scintigraphy for nodular thyroid tumors to establish the preoperative diagnosis. Scintigraphy was carried out in patients who exhibited cold nodules by 99mTc or 131I and high uptake in an early scan by 202Tl. Both procedures were performed in 54 patients within 10 minutes and 2 hours later after intravenous administration of 201TlCl. The scintigrams of 17 cases of the thyroid carcinomas [papillary adenocarcinoma in 14 cases, follicular adenocarcinoma in 2 cases, anaplastic carcinoma in 1 case] exhibited abnormally high activities in the early image corresponding to the cold nodules by 99mTc or 131I, and the activities remained clearly detectable in the delayed scintigram. In 6 benign cases [4 of follicular adenoma, and one each of adenomatous goiter and adenomatous goiter + follicular adenoma] abnormal activity still remained in the delayed image. These cases require careful follow-up, because they have high probability of developing carcinoma. It was found that the abnormal activity in the delayed scintigram almost always reflected malignant thyroid tumors while the activity that vanished in the delayed scintigram did not always reflect benign lesion. Thus the combination of early and delayed scintigraphy using 201TlCl appears tigraphy using 201TlCl appears to be useful in differentiating malignant thyroid tumors from benign ones. (author)

 
 
 
 
221

Diagnosis of intracranial malignant lymphoma by 67Ga and 201Tl SPECT  

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Six patients with malignant lymphoma of the brain underwent 67Ga and 201Tl brain SPECT. For the quantitative analysis, count ratios of a lesion to the normal brain (L/N) were calculated. In 201Tl SPECT studies, an L/N ratios ranged from 2.3 to 3.2, with a mean of 2.9±0.4. In 67Ga SPECT studies, an L/N ratios ranged from 4.4 to 6.6 with a mean of 5.7±0.8. 67Ga SPECT showed much more intense tracer uptake than 201Tl SPECT and the degree of 67Ga accumulation seems to be in proportion to the viability of malignant lymphoma. We came to the conclusion that quantitative 67Ga SPECT appears to be useful in detecting and managing malignant lymphoma in the brain. (author)

222

Removal of 99mTc and 201Tl by means of Lemna Gibba  

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In this work the capacity of the water macrophyte Lemna gibba coming from San Pedro Tultepec in the Mexico State was studied to remove the radioisotopes 99mTc and 201Tl, in order to show the capacity of this macrophyte for to treat some radioactive waste flowing that could contain this radioisotopes type. The removal capacity of 99mTc and 201Tl of the macrophyte Lemna gibba was determined using the batch method. In accordance with the values of the obtained Kd, the Lemna gibba with a size of particle diameter among 1mm - 300 ?m presents a better adsorption of 99mTc. The 201Tl is adsorbed better in the bioadsorbent when it has a size of particle diameter <150?m. (Author)

223

Functional significance of myocardial perfusion defects induced by dipyridamole using thallium-201 single-photon emission computed tomography and two-dimensional echocardiography  

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The mechanisms responsible for inhomogeneous myocardial blood flow after oral administration of a large dose (300 mg) of dipyridamole were assessed in 27 patients with serial thallium-201 single-photon emission computed tomography (SPECT) and simultaneous 2-dimensional echocardiograms. Myocardial tomographic images were obtained 50 minutes and 3 to 4 hours after administration of dipyridamole. Two-dimensional echocardiograms were recorded at baseline and then every 15 minutes for 60 minutes. Dipyridamole caused only a mild reduction in blood pressure (from 129 +/- 18 to 126 +/- 16 mm Hg) and a mild increase in heart rate (from 69 +/- 15 to 73 +/- 4 beats/min). Sixteen patients had perfusion defects after dipyridamole by SPECT, which underwent partial or total filling-in. Fourteen of these patients (87.5%) had either a new abnormality or further deterioration of a preexisting wall motion abnormality by 2-dimensional echocardiography, and thus were considered to have developed transient ischemia during dipyridamole administration. Ten of 11 patients (91%) with normal perfusion or fixed defects by SPECT had no further deterioration in wall motion after oral dipyridamole, and were thus considered to have no evidence of myocardial ischemia. In conclusion, most patients with transient thallium-201 defects after dipyridamole develop transient worsening of resting wall motion by 2-dimensional echocardiography, suggestive of true myocardial ischemia. Because myocardial oxygen rdial ischemia. Because myocardial oxygen demand, as indicated by the heart rate-blood pressure product, did not change significantly, the mechanism of myocardial ischemia in these patients is likely to be diminished regional blood flow related to a subendocardial steal induced by dipyridamole

224

Comparison of Myocardial perfusion by ECG-gated myocardial perfusion single photon emission computed tomography method with coronary angiography in all of the coronary vessels and individual coronary vessels in patients with suspected or known coronary artery disease  

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In order to compare myocardial perfusion using 99mTc Tetrofosmin ECG gated myocardial perfusion single photon emission computed tomography (ECG gated MP-SPECT) with coronary angiography, this descriptive study was performed in 47 patients. Sensitivity and specificity of myocardial perfusion scan with coronary angiography were calculated in all of the coronary vessels and individual coronary vessel. The sensitivity of perfusion scan of myocardium in case of LAD was 94.28% and the specificity was 91.66%. For LCX these figures were 82.35% and 90% and for RCA, 95.83% and 78.26% Respectively The overall sensitivity and specificity of myocardial perfusion scan in all of the coronary vessels was 91.66% and 81.81 % respectively. Our findings are consistent with other published studies. (author)

225

Dipyridamole-loading scintigraphy in patients with subendocardial infarction using single photon emission computed tomography  

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To detect myocardial lesions in patients with subendocardial (nontransmural) infarction, myocardial perfusion images of thallium-201 (Tl-201), using single photon emission computed tomography, were obtained in 17 patients during and three hours after coronary vasodilatation induced by the administration of dipyridamole. Controls consisted of 28 patients with transmural infarction and 11 with angina pectoris. Dipyridamole was infused intravenously at a rate of 0.142 mg/kg per min for four min, and the washout rate of Tl-201 was calculated by the segmental ROI method. Many patients with nontransmural infarction exhibited various Tl-201 myocardial perfusion images. The prevalence of redistribution among patients with nontransmural infarction was 88.2% (15 of 17), and its reverse redistribution was 64.7% (11 of 17). Every subject exhibited a number of abnormal Tl-201 myocardial perfusion images. In patients with nontransmural infarction the occurence of reverse redistribution images was significantly higher (64.7%) compared to those with transmural infarction (10.7%), and the occurrence of redistribution images was significantly higher (88.2%) compared to those with angina pectoris (45.5%). The abnormal perfusion images most frequently present in the areas corresponding to the sites of ST-T changes on ECG were reverse redistribution (26.7%), redistribution (17.3%), and fixed defect (6.7%) in order. The phenomenon of reverse redistribution images was found irrespective of ribution images was found irrespective of stenotic coronary artery lesions on selective coronary angiography. Most areas corresponding to the sites of reverse redistribution showed ST-T changes on ECG and high washout rates of Tl-201. (J.P.N.)

226

201Tl brain SPECT in differentiating central nervous system lymphoma from toxoplasmosis in AIDS patients  

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In AIDS patients, toxoplasmosis and lymphoma are the leading causes of CNS mass lesions. It is important to make the correct diagnosis expeditiously, since the two diseases require markedly different treatments and have different prognoses. In general, CT and MR imaging have failed to provide specific distinguishing characteristics to differentiate CNS lymphoma from toxoplasmosis, and it is difficult to differentiate these entities clinically. We performed 201Tl brain SPECT in order to differentiate two diseases. Counts ratio of a lesion to the normal brain (L/N ratio) was elevated in patients of lymphoma compared in patients of toxoplasmosis. 201Tl brain SPECT is useful to differentiate CNS lymphoma from toxoplasmosis. (author)

227

Measurement of effective dose equivalents around patients administered the radiopharmaceutical, 201TlCl  

International Nuclear Information System (INIS)

To estimate the dose equivalent (H1cm) of a person who may come into close contact with patients (pts) exposed to 201Tl dose rates around 15 adult pts (rest group: 8, exercise group: 7) have been measured with ionization survey meters. Measurements were carried out at 30 min, 24 h, 72 h, 144 h (or 120 h) and 216 h after the administration of 201TlCl. Survey meters were set up at the height of the first cervical vertebrae (I), xiphoid process (II) and anterior superior iliac spines (III) with the pt in a standing posture, and at distances of 0.05, 0.5, 1.0 and 1.5 m from the pt. The maximum H1cm rate of 18.37 ?Sv/h per 74 MBq was recorded at level II in the anterior projection. Doses in the posterior projection were similar to those at the anterior projection, however, in the right- and left-lateral projections the doses were lower than the anterior dose. The difference in doses between the rest and exercise groups was slight. The calculated effective half-life was 63.0 h. H1cms were 891, 196, 77 and 42 ?Sv/w per 74 MBq at distances of 0.05, 0.5, 1.0 and 1.5 m, respectively. These H1cms correspond to 84% of the total H1cms (?Sv/?h). The family of a patient given 201Tl was one-third of the total H1cms at 0.05 m, the dose did not exceed the dose limit described in recommendations-1990 of ICRP. However, it was a substantial doCRP. However, it was a substantial dose for them. Staff doses in general wards and in special wards (ICU or CCU) were one-fourth of a total H1cms at 0.5 m, these doses were the result of contact with 17 201Tl pts and 257 201Tl pts for one year. The dose of pt in the same room as pts given 201Tl were 42 ?Sv/w at 1.5 m; this dose did not exceed his dose limit of 100 ?Sv/w. These results do not suggest that radiation protection is necessary when exposed to a pt given 201Tl, but in the case of close contact with many 201Tl pts, it would be necessary when the radiation dose exceeds the limit. (author)

228

Comparison of flow capacities of arterial and venous grafts for coronary artery bypass grafting: evaluation with exercise thallium-201 single-photon emission tomography  

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Stress thallium-201 tomography was performed to compare the flow capacities of arterial and saphenous vein grafts in patients with coronary artery bypass grafting (CABG). One hundred and seven consecutive patients (95 male and 12 female; mean age 58{+-}9.1 years) underwent exercise-redistribution {sup 201}Tl myocardial single-photon emission tomography 4-5 weeks after CABG. When a reversible perfusion defect was present in the area covered by a patent bypass graft, the flow capacity of the graft was defined as insufficient. Of all 285 grafts, 211 were considered as complete bypass. Reversible perfusion defects were present in 29 (27%) of 108 myocardial areas supplied by patent arterial grafts but in only 5 (5%) of 103 myocardial areas supplied by patent saphenous vein grafts (P<0.0001). In the LAD area reversible defects were observed in 22 of 82 areas covered by arterial grafts, in contrast to only 1 of 29 areas covered by venous grafts (P<0.01); in the RCA area reversible defects were observed in 7 of 17 and 4 of 41 areas respectively (P<0.01). There was no difference between the native coronary artery stenosis bypassed by patent arterial and venous grafts (88%{+-}12% vs 86%{+-}14% respectively, P=0.27). In conclusion, flow capacities during peak myocardial demand were more frequently insufficient in arterial bypass grafts than in saphenous vein grafts. (orig.) With 2 figs., 4 tabs., 32 refs.

Taki, Junichi; Ichikawa, Akihiro; Nakajima, Kenichi; Tonami, Norihisa [Department of Nuclear Medicine, Kanazawa University School of Medicine, Kanazawa (Japan); Kawasuji, Michio [Department of Surgery (I), Kanazawa University School of Medicine, Kanazawa (Japan)

1997-12-01

229

Comparison of flow capacities of arterial and venous grafts for coronary artery bypass grafting: evaluation with exercise thallium-201 single-photon emission tomography  

International Nuclear Information System (INIS)

Stress thallium-201 tomography was performed to compare the flow capacities of arterial and saphenous vein grafts in patients with coronary artery bypass grafting (CABG). One hundred and seven consecutive patients (95 male and 12 female; mean age 58±9.1 years) underwent exercise-redistribution 201Tl myocardial single-photon emission tomography 4-5 weeks after CABG. When a reversible perfusion defect was present in the area covered by a patent bypass graft, the flow capacity of the graft was defined as insufficient. Of all 285 grafts, 211 were considered as complete bypass. Reversible perfusion defects were present in 29 (27%) of 108 myocardial areas supplied by patent arterial grafts but in only 5 (5%) of 103 myocardial areas supplied by patent saphenous vein grafts (P<0.0001). In the LAD area reversible defects were observed in 22 of 82 areas covered by arterial grafts, in contrast to only 1 of 29 areas covered by venous grafts (P<0.01); in the RCA area reversible defects were observed in 7 of 17 and 4 of 41 areas respectively (P<0.01). There was no difference between the native coronary artery stenosis bypassed by patent arterial and venous grafts (88%±12% vs 86%±14% respectively, P=0.27). In conclusion, flow capacities during peak myocardial demand were more frequently insufficient in arterial bypass grafts than in saphenous vein grafts. (orig.)

230

The comparative study of PET, SPECT imaging and pathology on experimental animal model of myocardial ischemia  

International Nuclear Information System (INIS)

Objective: To compare 201Tl SPECT and 18F-fluorodeoxyglucose (FDG) PET imaging for the assessment of myocardial viability of chronic myocardial ischemia in pigs. Methods: 201Tl SPECT imaging and 18F-FDG PET imaging were performed on 10 pig models of chronic myocardial ischemia induced by ameroid constrictors. The viable myocardial segments were also determined by pathologic hemotoxylin and eosin (HE) staining to identify myocardial changes. Results: In 81 myocardial segments, viable myocardial segments assessed by 18F-FDG PET and 201Tl SPECT imaging were 73(90.1%) and 62(76.5%) respectively, and were statistically different (?2=0.073, P>0.05). Conclusion: The accuracy of 18F-FDG PET imaging was much more higher than 201Tl SPECT imaging for the assessment of viable myocardium. (authors)

231

The usefulness of preoperative exercise stress myocardial single photon emission CT with thallium-201 to predict the responses to coronary revascularization  

International Nuclear Information System (INIS)

To evaluate the usefulness of preoperative exercise stress (Ex) myocardial single photon emission CT (SPECT) with thallium-201 to predict the responses to coronary revascularization (CRV), Ex-SPECT's were obtained in 42 patients with coronary artery disease (CAD). In 34 patients angioplasty was performed and in 18 patients coronary bypass surgery was undergone. Before and after CVR, Ex-SPECT's were obtained both at immediately after Ex (Initial) and 3 hours later (RD) by the rotating gamma camera. Initial images before CRV showed definite perfusion defects (+3) in 76 myocardial segments. Perfusion abnormalities at RD images were graded into (+3 to 0) by visual interpretation. '+3' indicated fixed defect and '0' indicated no perfusion abnormality. At RD images 17 segments showed fixed defect and 59 segments showed improved perfusion more than one grade. After CRV, all 59 segments with improved perfusion at RD images showed improvement of perfusion in comparison with initial images before CRV. Out of 17 segments with fixed defect before CRV, 14 segments showed perfusion defect with +3, while 3 segments showed improved perfusion after CRV. These 3 segments had ECG evidence of myocardial infarction. In these 3 segments, Ex-SPECT's before CRV showed abnormally low myocardial Tl washout rate (WOR) despite they indicated fixed defect visually. On the contrary, other 14 segments with fixed defect showed normal WOR before CRV. In conclusion, visually interpreted Ex-SPECT's befusion, visually interpreted Ex-SPECT's before CRV predict the myocardial perfusion after CRV in most of cases. In a small number (especially infarction segments) Ex-SPECT's before CRV cannot predict the improvement of myocardial perfusion after CRV by visual inspection, but WOR abnormality before CRV is useful to prospect their results. (author)

232

/sup 99m/Tc-pyrophosphate imaging in patients with acute myocardial infarction: Comparison of planar imaging with single-photon tomography with and without blood pool overlay  

International Nuclear Information System (INIS)

To test the hypothesis that single-photon emission computed tomography (SPECT) of /sup 99m/Tc-pyrophosphate (/sup 99m/Tc-PPi) with and without the overlay of tomographic blood pool scintigrams might detect small infarcts not identified by planar imaging, 52 patients were studied 3.2 +/- 2.0(SD) days after hospital admission for suspected acute myocardial infarction. Patients were chosen prospectively for tomographic study primarily, but not exclusively, because planar four-view imaging with /sup 99m/Tc-PPi was either negative or equivocal. SPECT was performed with a commercial rotating detector system immediately after planar imaging on one occasion. Corresponding /sup 99m/Tc-PPi and blood pool sections were mapped into opposite halves of a bichromic color table and displayed as an overlay. Planar images, SPECT and SPECT with blood pool overlay were interpreted separately and in random order without knowledge of clinical data. Seventeen patients had transmural infarcts (four anterior, 13 inferior), 19 had nontransmural infarcts, and 16 patients did not have acute myocardial infarction. The sensitivity of SPECT with blood pool overlay was significantly better than planar imaging for the entire group with myocardial infarction (97% vs 78%; p less than .025); this was primarily due to increased sensitivity in the detection of nontransmural myocardial infarction (95% vs 67%; p less than .05), although in one additional patient inferior transmural myocardial infarction waserior transmural myocardial infarction was also detected by the SPECT overlay technique. The specificities of the SPECT overlay technique and planar imaging were not significantly different; however, receiver operating characteristic analysis showed enhanced observer confidence with the tomographic method. SPECT without overlay was intermediate in sensitivity and specificity

233

Segmental analysis of 201-Tl emission computerized tomography of the heart. Evaluation by coronarographic data  

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Segmental analysis of SPECT 201-Tl stress study of the heart is a very sensitive and specific method highly predictive for coronary arteriosclerotic disease in the studied population. Distinction between single and multivessel disease was possible in 75% of the cases. In comparison with planar scintigraphy anomalies of the infero-posterior wall are better visualized

234

Reversible myocardial ischaemia or irreversible myocardial fibrosis  

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The results of biphasis 201thallium (201Tl) scanning were compared with those of coronary arteriography, left ventricular angiography and stress ECG in 56 patients with coronary artery disease and six with no evidence of heart disease. There were 104 201Tl defects, 50 of them reversible. The defects were always located in the area supplied by a critically stenotic coronary artery. Correlation of regional wall motion with 201Tl activity demonstrated that in all forms of abnormal wall motion there was either ischaemia or fibrosis. The resting LV angiogram thus does not make it possible to distinguish between myocardial ischaemia and fibrosis. Taking the LV angiogram as a standard, the rate of false-positive 201Tl scintigrams was 5%, that of false-negative ones 23%. The biphasic 201Tl scintigram was more sensitive than the stress ECG in detecting myocardial ischaemia. It furthermore made it possible to localize the ischaemic (or fibrotic) region within the LV and to estimate its size. (orig.)

235

Evaluation of myocardial viability with technetium-99m hexakis-2-methoxyiso-butylisonitrile and iodine-123 phenylpentadecanoic acid and single photon emission tomography  

International Nuclear Information System (INIS)

We applied combined planar and single photon emission tomography (SPET) to the non-invasive estimation of the left ventricular ejection fraction (LVEF), myocardial blood flow and free fatty acid uptake in the heart. Of the 31 patients with coronary artery disease, 25 had a previous myocardial infarction. All patients had at least one persistent perfusion defect on the stress-rest technetium-99m-Sestamibi study, and the results revealed 46% persistent perfusion defects. As a part of the perfusion study, the LVEF was measured at rest using the first-pass 99mTc-Sestamibi injection. Iodine-123 pPPA imaging at rest was performed within 2 weeks of the perfusion study. The 6-mm transaxial, sagittal and coronal slices of the perfusion and 123I-pPPA studies were reconstructed. Moreover an index of metabolic reserve (MR) was calculated by dividing the bull's eye of the 123I-pPPA study by the bull's eye of resting 99mTc-Sestamibi. Fourteen segments (25%) had a normal 123I-pPPA uptake with a MR value of 96%. Twenty-two segments (39%) had a partial 123I-pPPA uptake with a MR of 74%, whereas 21 segments (36%) had no 123I-pPPA uptake and a very low MR of 36%. There was a highly significant correlation between LVEF and MR. These findings suggest that it is possible to identify viable myocardium by measuring contractile function and myocardial perfusion and by combining these parameters with myocardial fatty ng these parameters with myocardial fatty acid uptake studies. (orig.)

236

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

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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 int...

Tokuchi, Y.; Isobe, H.; Takekawa, H.; Hanada, T.; Ishida, T.; Ogura, S.; Itoh, K.; Furudate, M.; Saito, K.; Kawakami, Y.

1998-01-01

237

Study of the predictors and lesion characteristics of ischemic heart disease patients with false negative results in stress myocardial perfusion single-photon emission tomography  

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The predictors and lesion morphology of patients with ischemic heart disease testing false negative results in stress myocardial perfusion single-photon emission computed tomography (SPECT) was investigated. Subjects were 58 consecutive patients who underwent coronary angiography (CAG), even though they showed normal findings in stress myocardial perfusion SPECT. Age, gender, methods of stress, perfusion agent, coronary risk factors, angina symptoms, and electrocardiographic changes were investigated as predictors by multivariate analysis. For lesion morphology, significant stenotic lesions were studied for morphological characteristics and reference diameter (RD), percentage diameter stenosis (%DS), minimum lumen diameter (MLD), and lesion length (LL) were measured. CAG revealed 30 significant stenotic lesions in 18 patients. Logistic regression analysis revealed significant predictors to be age (odds ratio (OR) 1.118, p<0.05), typical anginal pain (OR 21.09, p<0.01), and hypertension (OR 8.336, p<0.05). For lesion morphology, there were only 2 diffuse lesions and the mean RD, %DS, MLD, and LL were 3.03±0.9 mm, 63.1±9.3%, 1.13±0.49 mm, and 13.2±7.0 mm, respectively. Sufficient caution is believed necessary in the interpretation of normal findings of stress myocardial perfusion SPECT when the patient is elderly, complains of typical anginal pain, or has hypertension. In regard to characteristics of lesion morphology, there were hardly any diffuse lesions. (author)e hardly any diffuse lesions. (author)

238

Diagnostic value of 201Tl-chloride scintigraphy for thyroid tumors  

International Nuclear Information System (INIS)

Among the 98 cases of thyroid disease on whom we performed 201Tl-chloride scintigraphy, we examined 82 cases which were given histological diagnosis. Of 19 cases of thyroid carcinoma, 15 cases were positive (78.9%). 3 cases among the 15 showed a strong accumulation in the metastatic lymph nodes of the neck and mediastinum. Of 40 cases of thyroid adenoma, 10 cases were positive (25%). In comparison, cases of hyperthyroidism and chronic thyroiditis were all positive and cases of subacute thyroiditis were all negative. The histological types of thyroid tumors were examined. Of 14 cases of papillary carcinoma, 12 cases were positive (85.7%). 2 cases of negative scanning showed almost complete cystic degeneration. 3 cases of follicular carcinoma were all positive, but 2 cases of anaplastic carcinoma were negative. With respect to adenomas, 7 cases of tubular adenoma and 3 cases of trabecular adenoma were all positive, but cases of colloid adenoma and thyroid cyst were all negative. As to the uptake ratio of 201Tl-chloride into the thyroid carcinoma and adenoma tissue, it was observed that papillary carcinoma absorbed 2.65 times as much as normal thyroid tissue, follicular carcinoma absorbed 5.82 times as much, tubular adenoma absorbed 5.45 times as much, trabecular adenoma absorbed 5.67 times as much, but colloid adenoma absorbed 1.65 times as much as normal thyroid tissue. From the above mentioned results, it was concluded that 201Tl-chlor was concluded that 201Tl-chloride has no specific affinity for malignant tumors and cannot be used to discriminate between carcinoma and adenoma, but the nodule which showed positive scanning by 201Tl-chloride must be indicated for surgery. (author)

239

Evaluation of cellular viability by quantitative autoradiographic study of myocardial uptake of a fatty acid analogue in isoproterenol-induced focal rat heart necrosis  

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Previous studies led us to hypothesize that a fatty acid analogue, 15-p-iodophenyl-?-methyl pentadecanoic acid (IMPPA or BMIPP), which is taken up but not quickly metabolized by heart cells, would be a more suitable tracer of cellular viability that 201Tl. Biodistribution studies of 1-14C-IMPPA in conscious, freely moving rats showed that the concentration ratio of radioactivity in the heart with respect to the blood was about 8 for at least 60 min after intravenous administration, permitting its use as a putative tracer in these conscious, freely moving rats. Thereafter, the myocardial uptake of 14C-IMPPA was studied in isoproterenol-treated rats (daily treatment for 10 days in order to induce cardiac hypertrophy and necrotic foci) with respect to control ones. Comparison of myocardial localizations by quantitative autoradiography of the uptake of 201Tl and 14C-IMPPA with that of triphenyltetrazolium chloride (TTC) staining enabled comparative evaluation of nutritional blood flow, localization and uptake of 14C-IMPPA and necrotic foci size. Distributions of 14C-IMPPA and 201Tl in control rats' hearts were homogenous, like TTC staining. In infarcted hearts, areas of decreased 14C-IMPPA uptake were nearly the same (100%±5%) as those unstained by TTC. These areas were larger than those showing a decrease in thallium uptake (about 70%±5% of the total scar size). Therefor0%±5% of the total scar size). Therefore, IMPPA seems to be a more accurate and sensitive indicator of necrosis localization compared with thallium. It may be a useful agent for assessment of myocardial viability by single photon emission tomography (SPET) imaging. (orig.)

240

Myocardial scintigraphy and radionuclide ventriculography in myocardial infarction  

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149 patients with acute (n = 75) myocardial infarction and 74 postinfarctions, angiographically confirmed, were investigated by 201Tl myocardial scintigraphy and subsequent radionuclide ventriculography. Quantitative evaluation of the scintigram showed 201Tl storage defects in 92% in the acute stage and in 79% in the later stage. The sensitivity of identification of the posterior wall infarction was consistently markedly less than for anterior wall infarctions and could not be increased by additional application of 99sup(m)Tc methylene disphosphonate. By the combined application of myocardial scintigraphy and radionuclide ventriculography the functional effects of the infarction can be described non-invasively. (orig.)

 
 
 
 
241

Additive value of thallium single-photon emission computed tomography myocardial imaging for prediction of perioperative events in clinically selected high cardiac risk patients having abdominal aortic surgery.  

Science.gov (United States)

The present study was designed to prospectively evaluate whether reinjection thallium-201 single-photon emission computed tomography (SPECT) has a significant additive predictive value for occurrence of perioperative cardiac events in clinically selected patients at high cardiac risk undergoing abdominal aortic surgery. Of a group of 517 consecutive patients referred, 134 had > or = 2 of the following clinical or electrocardiographic cardiac risk variables: age > 70 years; history of myocardial infarction, angina, or congestive heart failure; diabetes mellitus; hypertension with severe left ventricular hypertrophy; and Q waves or ischemic ST-segment abnormalities on electrocardiogram at rest. Operation was performed after thallium SPECT study. Twelve patients (9%) had major perioperative events (cardiac death or nonfatal myocardial infarction) and 18 patients had other cardiac events (unstable angina, congestive heart failure, or severe ventricular tachyarrhythmia). Variables correlated with the occurrence of major events were history of myocardial infarction (p < 0.05) and the presence (p < 0.001) and number of segments with thallium reversible defects (p < 0.001). In multivariate analysis, history of myocardial infarction (p < 0.05) and the number of segments with reversible thallium defects (p < 0.001) were independent predictors. When all the cardiac events were taken into consideration, all the previous variables, as well as Q waves and ischemic ST abnormalities on the electrocardiogram, showed significant predictive value in both univariate and multivariate analyses. Furthermore, thallium SPECT imaging has an additive predictive value for major cardiac events over clinical and electrocardiographic risk factors. When performed on clinically selected patients at high cardiac risk undergoing abdominal aortic surgery, thallium SPECT demonstrates significant prognostic value for cardiac events over that provided by clinical variables alone. PMID:8546081

Vanzetto, G; Machecourt, J; Blendea, D; Fagret, D; Borrel, E; Magne, J L; Gattaz, F; Guidicelli, H

1996-01-15

242

Evaluation of myocardial viability with technetium-99m hexakis-2-methoxyiso-butylisonitrile and iodine-123 phenylpentadecanoic acid and single photon emission tomography  

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We applied combined planar and single photon emission tomography (SPET) to the non-invasive estimation of the left ventricular ejection fraction (LVEF), myocardial blood flow and free fatty acid uptake in the heart. Of the 31 patients with coronary artery disease, 25 had a previous myocardial infarction. All patients had at least one persistent perfusion defect on the stress-rest technetium-99m-Sestamibi study, and the results revealed 46% persistent perfusion defects. As a part of the perfusion study, the LVEF was measured at rest using the first-pass {sup 99m}Tc-Sestamibi injection. Iodine-123 pPPA imaging at rest was performed within 2 weeks of the perfusion study. The 6-mm transaxial, sagittal and coronal slices of the perfusion and {sup 123}I-pPPA studies were reconstructed. Moreover an index of metabolic reserve (MR) was calculated by dividing the bull's eye of the {sup 123}I-pPPA study by the bull's eye of resting {sup 99m}Tc-Sestamibi. Fourteen segments (25%) had a normal {sup 123}I-pPPA uptake with a MR value of 96%. Twenty-two segments (39%) had a partial {sup 123}I-pPPA uptake with a MR of 74%, whereas 21 segments (36%) had no {sup 123}I-pPPA uptake and a very low MR of 36%. There was a highly significant correlation between LVEF and MR. These findings suggest that it is possible to identify viable myocardium by measuring contractile function and myocardial perfusion and by combining these parameters with myocardial fatty acid uptake studies. (orig.).

Kuikka, J.T.; Mussalo, H.; Hietakorpi, S.; Vanninen, E.; Laensimies, E. (Kuopio Univ. Hospital (Finland). Dept. of Clinical Physiology Kuopio Univ. Hospital (Finland). Dept. of Medicine)

1992-10-01

243

Global and regional left ventricular function and tomographic radionuclide perfusion: the Western Washington Intracoronary Streptokinase In Myocardial Infarction Trial  

International Nuclear Information System (INIS)

The Western Washington Intracoronary Streptokinase In Myocardial Infarction Trial enrolled 250 patients with acute myocardial infarction. After the coronary angiographic diagnosis of thrombosis, patients were randomly assigned to receive either conventional therapy with heparin or intracoronary streptokinase followed by heparin. Of the 232 patients who survived at least 60 days, 207 (89%) underwent radionuclide ventriculographic determination of global and regional ejection fraction at a single institution at 62 +/- 35 days after infarction. In the first 100 patients, infarct size was also determined by quantitative single-photon emission tomographic imaging with thallium-201 (201Tl) and expressed as a percentage of the left ventricle with a perfusion defect. Overall, global ejection fraction did not differ between patients treated with streptokinase (45.9 +/- 13.9%; n . 115) and control patients (46.1 +/- 14.4%; n . 92, p . NS). Similarly, the regional posterolateral, inferior, and anteroseptal ejection fraction did not differ between the two groups. Infarct size as measured by 201Tl tomography was 19.4 +/- 12.8% (n . 52) of the left ventricle for the streptokinase group and 19.6 +/- 11.8% (n . 48; p . NS) for the control group. When patients were compared within groups by electrocardiographic location of infarction, time to treatment, or the presence or absence of vessel opening, there were no significant differences between streptokinase and cnt differences between streptokinase and control patients. Statistical inclusion of the 18 patients who died early and were unavailable for study also failed to modify the results, except for a possible reduction in inferior infarct size as measured by 201Tl tomography

244

Study of myocardial viability using thallium-201 in patients with a history of infarctions: Is reinjection necessary?  

International Nuclear Information System (INIS)

An analysis was performed of 84 patients with a history of myocardial infarction using the thallium-single photon emission computed tomography (SPECT) test and employing the technique of reinjection of the radioisotope 201Tl at rest. A study was conducted during the period of maximum stress, four hours and one hour after reinjection of 37 MBq of 201Tl. The presence and extent of reperfusion was determined. In addition, the incidence of ischaemia was correlated with four clinical parameters which might influence its occurrence: development period of the infarction (greater or less than 30 days), Q wave in the electrocardiogram, prior use of streptokinase, and angina. Twenty-seven patients exhibited partial reperfusion at rest which increased significantly in 14 of the patients after thallium reinjection. Moreover, 22 patients only exhibited reperfusion with reinjection. There was no relation between the clinical parameters evaluated and the incidence of ischaemia. In conclusion, with thallium reinjection 43% more patients can be detected with viable areas of myocardium which are not evident at rest. The clinical parameters evaluated are no help in predicting ischaemia with thallium. The routine use of reinjection is recommended to evaluate myocardial viability in patients with a history of infarction. (author). 14 refs, 2 figs

245

Evaluation of malignancy and viability of brain tumors by 201Tl SPECT. The correlation between 201Tl SPECT and pathology, clinical progress and the intensity of enhancement on CT images  

International Nuclear Information System (INIS)

Thallium-201 (201Tl) SPECT was performed 48 times in 26 patients to clarify its usefulness in the evaluation of malignancy and viability of brain tumors. The early counts ratio (ER) and delayed counts ratio (DR) of a lesion compared with normal brain were obtained 10-15 minutes and 3 hours, respectively, after intravenous administration of 185 MBq of 201Tl chloride. Untreated high grade malignant tumors and recurrent tumors did not always show high ER and DR, and they were widely distributed. High grade malignant tumors that showed low ER and DR were not well enhanced on CT or MRI. In low grade malignant tumors, such as pituitary adenoma which was well enhanced on CT, ER and DR were as high as in high grade malignant tumor. Whether a tumor recurred within three months after radiotherapy or not was retrospectively predicted as accuracy rates of 93.8% and 87.5% with cut-off points of 4.0 for ER and 3.5 for DR. Cerebral radiation necrosis showed ring-like increased uptake of 201Tl in proportion to the progress of necrosis and intensity of enhancement on MRI. In conclusion 201Tl SPECT is considered to be less useful for lesions that are well enhanced on CT, because they show high uptake of 201Tl regardless of their malignancy and viability. On the other hand, in tumors that are not well enhanced on CT, 201Tl shows good accumulation in viable and high grade malignant lesions. 201Tl SPECT should be lesions. 201Tl SPECT should be performed on such cases. (author)

246

Clinical evaluation of myocardial SPECT using 99mTc-tetrofosmin (PPN 1011) in patients with ischemic heart disease  

International Nuclear Information System (INIS)

Myocardial SPECT was performed in seven patients with ischemic disease using 99mTc-tetrofosmin (PPN 1011) and 201Tl. A comparison of findings between 99mTc-tatrofosmin and 201Tl on each segment by segmental analysis showed concordance in 70% of total segments and showed discordance in 45% of posterior-inferior segments. Positive predictive value of 99mTc-tetrofosmin was superior to that of 201Tl in the infero-posterior segments. 99mTc-Tetrofosmin was considered to be a useful agent for evaluation of myocardial perfusion in the ischemic heart disease, especially in infero-posterior myocardial wall of the left ventricle. (author)

247

False-positive defects in technetium-99m sestamibi myocardial single-photon emission tomography in healthy athletes with left ventricular hypertrophy  

International Nuclear Information System (INIS)

Exercise ECG and myocardial single-photon emission tomography (SPET) are fundamental in the non-invasive evaluation of patients suspected of having coronary artery disease (CAD). The purpose of the present study was to investigate the influence of physiological left ventricular hypertrophy (LVH) on myocardial sestamibi SPET in healthy young and old athletes. Eighteen young male elite athletes (ten rowers, five power/weight lifters and three triathletes) and 14 well-trained elderly rowers were studied. All underwent a bicycle test as part of a 2-day sestamibi SPET protocol. Attenuation correction was not performed. The studies were evaluated visually and quantitatively analysed by the CEqual program with its reference files and with a file from a local non-athletic age-matched population. Echocardiographic LVH was an inclusion criterion in the young athletes. Exercise ECG was normal in all subjects. In at least three of the young athletes a reversible defect was observed by visual analysis. On quantitative analysis one-third of the young athletes had ''significant'' (>10 pixels) defects compared with both the local reference base and the CEqual reference population. Nearly all defects were found in the anterior or inferior wall. The remaining subjects, including all old rowers, had normal SPET findings. Anterior and inferior wall defects are so common in healthy athletes with physiological LVH that the specificity of myocardial SPET, in contrast to exercise ECG, seems SPET, in contrast to exercise ECG, seems to be too low for evaluation of chest pain in this group. The mechanism of anterior and inferior defects may be related to hot spots (papillary muscles?) in the lateral wall. The specificity of SPET is maintained in athletes without LVH. (orig.)

248

The importance of mild inferolateral wall ischemia on myocardial single photon emission computed tomography (SPECT with 99mTc-MIBI using 20 left ventricular segments model  

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Full Text Available Introduction: The mild ischemia in the inferolateral wall on myocardial perfusion imaging was seen frequently in practice .The aim of this study is to assess the importance of the above issue on myocardial perfusion SPECT with coronary angiography. Methods: All patients with mild ischemia of the inferolateral wall on the myocardial single photon emission computed tomography with 99mTc-MIBI using 20 left ventricular segments model were enrolled to this study. For all cases, a questionnaire including type of chest pain, risk factors and , previous examinations were filled out. Then, all case was follow up for one year. Luminal stenosis of >50% was classified as significant stenosis on coronary angiography. A p value < 0.05 was considered to be statistically significant. Results: During 2 year investigation, 105 cases had mild ischemia on MPI which 36 subjects (22 male and 14 female underwent coronary angiography. The mean age was 56 year old (age range ; 36-73 year. In total, 25 cases had stenosis in angiography. Ten cases had stenosis in one vessel, 3 in two vessels and 12 cases had stenosis in three vessels. The inferolateral wall was corresponded to left circumflex territory. Nineteen out of 36 (52.7% cases had stenosis in LCX. Twenty-three of them (63.9% underwent revascularization during one year follow up. In multiple logistic regressions with LCX stenosis on angiography as dependent variable, we observed that only the abnormal MPI was independently associated significantly. Conclusion: The findings of the study may indicate that even mild perfusion defect in the inferolateral wall especially in high risk subjects for coronary artery disease should be carefully managed.

Majid Assadi

2010-10-01

249

Thallium-201 single photon emission computed tomography imaging of meningioma cells in hyperostosis  

International Nuclear Information System (INIS)

Hyperostosis is a well-known bony reaction associated with meningioma. However, it is difficult to determine preoperatively whether meningioma cells have invaded the bone, and if so, the extent of tumor invasion. Preoperative thallium-201 chloride single photon emission computed tomography (201Tl SPECT) was performed in four patients with meningioma and hyperostosis. The presence of meningioma cells in bone biopsy specimens was also investigated using standard histological techniques. 201Tl SPECT revealed increased uptake in three of the four patients. Biopsy specimens from these three patients revealed invasion of the bony lesions by meningioma cells in accordance with the 20lTl SPECT findings. 20lTl SPECT found no abnormal uptake in the other patient, in which there was also no histological evidence of tumor invasion of bone. Preoperative 20lTl SPECT can provide information on bone invasion by meningioma, which will facilitate preoperative planning of the extent of bony resection required at meningioma surgery. (author)

250

Classification of 201TL and sup(99m)Tc-pertechnetate leg scan patterns and evaluation of their clinical significance  

International Nuclear Information System (INIS)

Classification of the 201Tl and sup(99m)Tc-pertechnetate (sup(99m)TcOsub(4-)) leg scan patterns and their clinical significance were evaluated in the patients with ischemic diseases of the lower extremities (IDL) Five patterns were distinguished in both 201Tl and sup(99m)TcOsub(4-) leg scans; A: decreased activity throughout the affected leg, B: localized decreased activity in the affected leg, C: localized decreased activity associated with increased activity in the affected leg, D: generalized of localized increased activity in the affected leg and E: no laterality of the activity. 201Tl and sup(99m)TcOsub(4-) leg scan patterns were agreed in 55% of the patients. 201Tl leg scan had tendency to correlate the level of the vascular lesion in pattern B and C,However, diagnosis of the level of the lesion was difficult from the leg scan. Pattern D of the 201Tl leg scan was associated with increased blood flow in the affected leg on radionuclide angiography in 42% of the patients. After surgery, sup(99m)TcOsub(4-) leg scan tended to show pattern D, especially in the patients with lumbar sympathectomy. Patterns A, B and C were thought to suggest the ischemia. Patterns C and D were thought to express reactive hyperemia induced by the ischemic lesion. In the 60 preoperative IDL, sensitivity of 201Tl leg scan alone was 76% and that of combined use of 201Tl and sup(99m)TcOsub(4-) leg scans was 85%. Add sup(99m)TcOsub(4-) leg scans was 85%. Addition of radionuclide angiography increased sensitivity of IDL upto 98% and accuracy was 98%. Combined use of 201Tl and sup(99m)TcOsub(4-) leg scans and radionuclide angiography was useful for detection of IDL, and was also useful for evaluation of the results of the surgical intervention. (J.P.N.)

251

Clinical evaluation of /sup 201/Tl-chloride scintigraphy in thyroid tumor  

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/sup 201/Tl-chloride scintigraphy was performed for the purpose of distinguishing cold thyroid nodules by /sup 123/I and/or sup(99m)Tc pertechnetate. Included in this study were 45 cases, consisting of 16 of thyroid cancer and 29 of benign lesions. Scans were performed 10 minutes (early scan) and 2 hours (delayed scan) after injection of /sup 201/Tl. Early scintigrams showed warm or hot nodules in all cases except benign cystic lesions. Delayed scintigrams showed increased accumulations of radioactivities in a large number of malignant cases and a few cases of adenoma. Delayed scitigraphy might be clinically useful in differentiating malignant thyroid nodules from benign nodules. Positive images of metastatic lesions were visualized in three cases of thyroid cancer.

Eguchi, Seiichi; Yokoyama, Takashi; Matsumoto, Tsuneo (Yamaguchi Univ., Ube (Japan). School of Medicine)

1983-10-01

252

201Tl+-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy  

Science.gov (United States)

Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive 201Tl+ to obtain new nanoprobes as radiotracers for 201-thallium-based imaging.Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive 201Tl+ to obtain new nanoprobes as radiotracers for 201-thallium-based imaging. Electronic supplementary information (ESI) available: Experimental details and procedures, toxicological data, PXRD, TEM images, kinetics and adsorption isotherms, SPECT/CT images, Tl+ captation profiles. See DOI: 10.1039/c4nr03044c

Perrier, M.; Busson, M.; Massasso, G.; Long, J.; Boudousq, V.; Pouget, J.-P.; Peyrottes, S.; Perigaud, Ch.; Porredon-Guarch, C.; de Lapuente, J.; Borras, M.; Larionova, J.; Guari, Y.

2014-10-01

253

Effect of eating on thallium myocardial imaging  

International Nuclear Information System (INIS)

To determine if eating between initial and delayed thallium images alters the appearance of the delayed thallium scan, a prospective study was performed; 184 subjects sent for routine thallium imaging were randomized into two groups, those who ate a meal high in carbohydrates between initial and delayed thallium myocardial images (n = 106), and those who fasted (n = 78). The 201Tl images were interpreted in blinded fashion for global myocardial and pulmonary clearance of 201Tl myocardial defects. The eating group had a significantly lower incidence of transient myocardial defects compared to the noneating group (7 percent vs 18 percent, respectively; p less than 0.05). The time between initial and delayed images and the incidence of exercise-induced ischemic ST-segment depression or pathologic Q waves on the electrocardiogram were not significantly different between the two groups. These data suggest that eating a high-carbohydrate meal between initial and delayed 201Tl images causes increased 201Tl myocardial clearance rates and may alter 201Tl myocardial redistribution over time

254

201Tl-chloride thyroid scintigraphy to evaluate benign and/or malignant nodules: usefulness of the delayed scan  

International Nuclear Information System (INIS)

The purpose of this study is to evaluate benign and/or malignant thyroid tumors with 201Tl thyroid scan. Researchers studied 76 cases of histologically verified thyroid tumors, all seen as cold nodules on the 123I thyroid scan. 201Tl thyroid scan was performed 5-15 minutes (early scan) and 3-5 hours (delayed scan) after intravenous administration of 1.5-2.0 mCi of 201Tl. In 35 (94.6%) of 36 malignant tumors (anaplastic carcinoma, six; papillary carcinoma 23; follicular carcinoma, five; epidermoid carcinoma, one; malignant lymphoma, 1) 201Tl accumulated in the cold nodule of the 123I thyroid scan on both early and delayed scans. On the other hand, the delayed 201Tl scan was negative in 35 out of 39 (89.7%) benign tumors. Employing early and delayed 201Tl scans, researchers were able to differentiate most malignant thyroid tumors from those which were benign. False-negative and -positive cases are discussed

255

Clinical application of 201Tl brain SPECT imaging of brain tumors  

International Nuclear Information System (INIS)

Objective: To investigate the clinical value of 201Tl SPECT brain imaging in histologic grading of brain tumors. Methods: Early and delayed SPECT brain imaging were performed at 15 min and 3 hours after an intravenous injection of 111 MBq of 201Tl was given in 7 normal subjects, 3 patients with brain hematoma and 50 patients with brain tumors. Semiquantitative data were obtained as early and delayed uptake index and retention index (RI) in 25 patients with brain tumors and in all patients with brain hematoma and normal subjects. Results: In 7 normal subjects, no radioactivity was observed in brain substance. In all patients with brain hematoma or tumors, a high tracer uptake was detected in lesions on the early imaging. But the radioactivity in lesions varied with the nature of the lesions on delayed imaging. The radioactivity reduced remarkably in brain hematoma (average RI 0.61). The radioactivity was stable or reduced slightly in benign or low-grade tumors (average RI = 0.96 +- 0.08). And the radioactivity was increased evidently in high-grade tumors (average RI = 1.19 +- 0.06). Conclusions: Results of the study indicate that 201Tl brain SPECT early and delayed imaging is very useful in brain tumor localization, distinguishing low-grade from high-grade brain tumors, and in prognosticating the patients with brain tumor. 201Tl brain SPECT may offer the most accurate assessment of the response of tumors to therapeutic measure response of tumors to therapeutic measures been used, too

256

Preparation and biodistribution of [201Tl](III)vancomycin complex in normal rats  

International Nuclear Information System (INIS)

Thallium-201 (T1/2 = 3.04 days) in Tl+ form was converted to Tl3+ cation in presence of O3 in 6 M HCl controlled by RTLC/gel electrophoresis methods. The final evaporated activity was reacted with vancomycin (VAN) in water to yield [201Tl](III)VAN. The best results were obtained at room temperature in water after 30 min with a radiochemical yield >99%, after mixing the reactants followed by SPE purification using Si Sep-Pak. The studies showed that thallic ion is mostly incorporated into vancomycin with a radiochemical purity of more than 98 ± 1% by RTLC. A specific activity of about 4.14·1010 Bq/mmol was obtained. Radiochemical purity and stability of 201Tl-VAN in the preparation and in presence of human serum was determined up to 5.5 days. Biodistribution study of 201Tl(III)-vancomycin in normal rats was performed up to 52 h. (authors)

257

The diagnostic significance of diffuse lung uptake of 201Tl chloride in diffuse interstitial pneumonia  

International Nuclear Information System (INIS)

Scintigraphy with 201TlCl and 197HgCl2 was performed in 323 patients with various respiratory diseases. Diffuse, marked bilateral lung uptake of 201Tl or 197Hg was demonstrated in 2 of 3 cases with hypersensitivity pneumonitis, 26 of 29 cases with silicosis and 28 of 29 cases with diffuse interstitial pneumonia, but in diffuse panbronchiolitis, chronic bronchitis and pulmonary emphysema, only slight lung uptake or negative results were obtained in most cases. In diffuse interstitial pneumonia, no close correlation was observed between the grade of the lung uptake and the various clinical findings such as fever, cough, rales, ESR, S-LDH, ?1-globulin, %VC, PaO2 and so on. With regard to roentgenological findings, marked lung uptake was observed in cases not only with reticulonodular shadows but also those with ring shadows and those without any shadows. Concerning the microscopic findings of lung biopsy specimens, marked uptake was observed in cases with slight interstitial fibrosis as well as infiltration of mononuclear cells. The right ventricle was visualized in 13 of 19 cases (68.4%) with diffuse interstitial pneumonia. Lung scintigraphy with 201Tl chloride is non-invasive and seems a more sensitive indicator of diffuse intersitial changes such as inflammatory disorders than the clinical findings, chest X-ray and so on. (author)

258

Sex-specific criteria for interpretation of thallium-201 myocardial uptake and washout studies  

International Nuclear Information System (INIS)

A study was undertaken to determine the effect of gender on criteria for the quantitative analysis of exercise-redistribution 201Tl myocardial scintigraphy. The studies of 26 normal females and 23 normal males were subjected to bilinear interpolative background subtraction and horizontal profile analysis. Significant sexual differences were found in both regional uptake ratios and washout rates. These differences primarily reflected a proportionately decreased anterior and upper septal uptake in females, and faster washout in females. Faster myocardial 201Tl washout rates in females could not be clearly ascribed to either a physiological or artifactual explanation. It is concluded that since important differences exist between males and females in the detected pattern of 201Tl myocardial uptake and washout, sex-specific criteria may enhance the predictive accuracy of exercise-redistribution 201Tl myocardial scintigraphy

259

The development of radioiodinated 3-methyl-branched fatty acids for evaluation of myocardial disease by single photon techniques  

International Nuclear Information System (INIS)

The authors briefly review their efforts over the last few years to develop a radioiodinated fatty acid which could be used to evaluate regional myocardial uptake, and discuss in detail their current studies with radioiodinated 3-methyl-branched fatty acids and their use as research tools to study regional fatty acid uptake in hypertensive rats by autoradiography. Also described are a series of patient studies with 15-(p-[123I]iodophenyl)-3-R, S-methylpentadecanoic acid and a comparison of the properties of this agent and the straight-chain analogue 15-(p-iodophenyl)pentadecanoic acid. (Auth.)

260

Significance of exercise-induced ST segment depression in patients with myocardial infarction involving the left circumflex artery. Evaluation by exercise thallium-201 myocardial single photon emission computed tomography  

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The significance of exercise-induced ST segment depression in patients with left circumflex artery involvement was investigated by comparing exercise electrocardiography with exercise thallium-201 single photon emission computed tomography (Tl-SPECT) and the wall motion estimated by left ventriculography. Tl-SPECT and exercise electrocardiography were simultaneously performed in 51 patients with left circumflex artery involvement (angina pectoris 30, myocardial infarction 21). In patients with myocardial infarction, exercise-induced ST depression was frequently found in the V{sub 2}, V{sub 3} and V{sub 4} leads. In patients with angina pectoris, ST depression was frequently found in the II, III, aV{sub F}, V{sub 5} and V{sub 6} leads. There was no obvious difference in the leads of ST depression in patients with myocardial infarction with ischemia and without ischemia on Tl-SPECT images. In patients with myocardial infarction, the lateral wall motion of the infarcted area evaluated by left ventriculography was more significantly impaired in the patients with ST depression than without ST depression (p<0.01). Exercise-induced ST depression in the precordial leads possibly reflects wall motion abnormality rather than ischemia in the lateral infarcted myocardium. (author)

Koitabashi, Norimichi; Toyama, Takuji; Hoshizaki, Hiroshi [Gunma Prefectural Cardiovascular Center, Maebashi (Japan)] [and others

2000-04-01

 
 
 
 
261

Significance of exercise-induced ST segment depression in patients with myocardial infarction involving the left circumflex artery. Evaluation by exercise thallium-201 myocardial single photon emission computed tomography  

International Nuclear Information System (INIS)

The significance of exercise-induced ST segment depression in patients with left circumflex artery involvement was investigated by comparing exercise electrocardiography with exercise thallium-201 single photon emission computed tomography (Tl-SPECT) and the wall motion estimated by left ventriculography. Tl-SPECT and exercise electrocardiography were simultaneously performed in 51 patients with left circumflex artery involvement (angina pectoris 30, myocardial infarction 21). In patients with myocardial infarction, exercise-induced ST depression was frequently found in the V2, V3 and V4 leads. In patients with angina pectoris, ST depression was frequently found in the II, III, aVF, V5 and V6 leads. There was no obvious difference in the leads of ST depression in patients with myocardial infarction with ischemia and without ischemia on Tl-SPECT images. In patients with myocardial infarction, the lateral wall motion of the infarcted area evaluated by left ventriculography was more significantly impaired in the patients with ST depression than without ST depression (p<0.01). Exercise-induced ST depression in the precordial leads possibly reflects wall motion abnormality rather than ischemia in the lateral infarcted myocardium. (author)

262

Effects of low-dose dobutamine on left ventricular function in normal subjects as assessed by gated single-photon emission tomography myocardial perfusion studies  

International Nuclear Information System (INIS)

Electrocardiography gated single-photon emission tomography (gated SPET) allows the assessment of regional perfusion and function simultaneously and in full spatial congruency. In this study changes in global and regional left ventricular function in response to dobutamine infusion were assessed in ten healthy volunteers using sequential gated SPET myocardial perfusion acquisitions. Four consecutive gated SPET images were recorded 60 min after injection of 925 MBq technetium-99m tetrofosmin on a three-head camera equipped with focussing collimators. Two acquisitions were made at rest (baseline 1 and 2), and the third and fourth acquisitions were started 5 min after the beginning of the infusion of 5 and 10 ?g kg-1 min-1 dobutamine, respectively. Systolic wall thickening (WT) was quantified using a method based on circumferential profile analysis. Left ventricular ejection fraction (LVEF) and volumes were calculated automatically using the Cedars-Sinai program. Nine of the ten subjects presented a definite increase in WT during dobutamine infusion. WT increased on average from 46%±14% at baseline to 71%±23% (range: 37%-106%; P-1 min-1 dobutamine infusion and to 85%±25% (range: 62%-123%; P-1 min-1) during 10 ?g kg-1 min-1 dobutamine infusion. Apical segments showed the largest WT at baseline. The average WT response to doline. The average WT response to dobutamine was similar for all parts of the myocardium. It is concluded that changes in WT induced by infusion of low-dose dobutamine can be assessed by sequential gated SPET myocardial perfusion studies. The ''stress gated SPET'' protocol proposed in this study might be helpful to distinguish viable from scar tissue in patients with coronary artery disease, by demonstrating a preserved inotropic response in hypoperfused myocardium. (orig.)

263

Iodine-123 N-methyl-4-iododexetimide: a new radioligand for single-photon emission tomographic imaging of myocardial muscarinic receptors  

International Nuclear Information System (INIS)

Cardiac muscarinic receptor ligands suitable for positron emission tomography have previously been characterised. Attempts to develop radioligands of these receptors suitable for single-photon emission tomographic (SPET) imaging have not been successful due to high lung retention and high non-specific binding of previously investigated potential tracers. The purpose of this study was to evaluate the biodistribution and in vivo imaging characteristics of a new radiopharmaceutical, [123I]N-methyl-4-iododexetimide. Biodistribution studies performed in rats showed high cardiac uptake (2.4% ID/g) 10 min after injection with a heart to lung activity ratio of 5:1. Specificity and stereoselectivity of cardiac binding were demonstrated using blocking experiments in rats. Dynamic imaging studies in anaesthetised greyhounds demonstrated rapid and high myocardial uptake and low lung binding with stable heart to lung activity ratios of >2.5:1 between 10 and 30 min, making SPET imaging feasible. Administration of an excess of an unlabelled muscarinic antagonist, methyl-quinuclidinyl benzylate rapidly displaced myocardial activity to background levels and the pharmacologically inactive enantiomer, [123I]N-methyl-4-iodolevetimide, had no detectable cardiac uptake, indicating specific and stereoselective muscarinic receptor binding. SPET revealed higher activity in the inferior than in the anterior wall, this being consistent with previously described regional vatent with previously described regional variation of cardiac parasympathetic innervation. [123I]N-methyl-4-iododexetimide shows promise as an imaging agent for muscarinic receptor distribution in the heart and may be helpful in evaluating diverse cardiac diseases associated with altered muscarinic receptor function, including heart failure and diabetic heart disease. (orig.)

264

[The examination of attenuation correction using one computed tomography scan in myocardial perfusion stress-rest single photon emission computed tomography].  

Science.gov (United States)

Attenuation correction (AC) of myocardial perfusion stress-rest single photon emission computed tomography (SPECT) with hybrid SPECT/computed tomography (CT) is effective. But because CT scan is done two times, the radiation exposure of patients increases. Therefore, we suggested a new method of AC that can correct attenuation of SPECT images acquired during a rest examination by using the CT scan during a stress examination. AC was done using one CT scan and we evaluated the clinical appropriateness of using this method. Matters of this study were (1) positional reproducibility of data analysis machine (Xeleris) (2) phantom study: accuracy of registration by manual and repetition reproducibility (3) clinical study using (99m)Tc-tetrofosmin. Comparison methods were analyzed by calculating the difference perfusion (Dp) with 17-segments model of American Heart Association and visual evaluation of three axis images in the myocardium. In the phantom study, because most of the score of 17-segments accord (Dp?1), it was considered that the shift on SPECT/CT's bed was reproduced by the shift on Xeleris. And it is shown that AC with CT scan on deference point was accuracy. In the clinical study, there were a few differences in Dp (Dp?4) and approximately equal evaluation on visual evaluation was provided, which compared with conventional methods. Because AC of myocardial perfusion stress-rest SPECT by one CT scan showed that it was approximately equal in evaluation compared with conventional methods, we expect to be able to use this method in clinical cases. PMID:22975698

Sasaki, Makoto; Kawase, Shigeto; Miyazaki, Yoshihiro; Fujimoto, Takahiro; Higashimura, Kyouji

2012-01-01

265

Myocardial infarction determined by technetium-99m pyrophosphate single-photon tomography complicating elective coronary artery bypass grafting for angina pectoris  

International Nuclear Information System (INIS)

The incidence of acute myocardial infarction (AMI) complicating coronary artery bypass grafting (CABG) has previously been based on concordance of electrocardiographic, enzymatic and scintigraphic criteria. Technetium-99m pyrophosphate (Tc-PPi) single-photon emission computed tomography now enables detection of AMI with high sensitivity and specificity. Using this technique, perioperative AMI was detected in 12 of 58 patients (21%) undergoing successful elective CABG for stable angina pectoris. Stepwise multivariate logistic regression analysis was performed to compare the predictive value of preoperative (New York Heart Association class, left ventricular ejection fraction and use of beta blockers) and intraoperative (number of grafts constructed, use of internal mammary anastomoses, use of sequential saphenous vein grafts, smallest grafted distal vessel lumen caliber and aortic cross-clamp time) variables. Preoperative New York Association class (p = 0.04) and smallest grafted distal vessel lumen caliber (p = 0.03) were significant multivariate predictors of perioperative AMI. Only 1 perioperative patient with AMI (and 1 pyrophosphate-negative patient) developed new Q waves. Serum creatine kinase-MB was higher in patients with AMI by repeated measures analysis of variance (p = 0.0003). Five AMIs occurred in myocardial segments revascularized using sequential saphenous vein grafts, and 7 in segments perfused by significantly stenosed epicardial vessels with distal lustenosed epicardial vessels with distal lumen diameter and perfusion territory considered too small to warrant CABG. At 6-month follow-up, the mean left ventricular ejection fraction increased from 0.61 to 0.65 in Tc-PPI-negative patients (p = 0.01), but not in perioperative patients with AMI

266

Evaluation of myocardial viability with technetium-99m hexakis-2-methoxyisobutyl isonitrile and iodine-123 phenylpentadecanoic acid and single photon emission tomography.  

Science.gov (United States)

The detection of viable myocardium in infarcted regions, i.e. hibernating myocardium, is a major goal in clinical cardiology today. We applied combined planar and single photon emission tomography (SPET) to the non-invasive estimation of the left ventricular ejection fraction (LVEF), myocardial blood flow and free fatty acid uptake in the heart. Of the 31 patients with coronary artery disease, 25 (81%) had had a previous myocardial infarction. All patients had at least one persistent perfusion defect on the stress-rest technetium-99m hexakis-2-methoxyisobutyl isonitrile (Sestamibi) study, and the results revealed 57/124 (46%) persistent perfusion defects. As a part of the perfusion study, the LVEF was measured at rest using the first-pass 99mTc-Sestamibi injection, and the mean LVEF was 47% +/- 9% (mean +/- 1 standard deviation). Iodine-123 phenylpentadecanoic acid (123I-pPPA) imaging at rest was performed within 2 weeks from the perfusion study. Then 6-mm transaxial, sagittal and coronal slices of the perfusion and 123I-pPPA studies were reconstructed. The bull's eye displays of the coronal slices were visually surveyed and divided into 4 quadrants: anterior, lateral, posterior and septal. The following image score was used: 0 = fixed defect, 1 = partial uptake and 2 = normal uptake. Moreover an index of metabolic reserve (MR) was calculated by dividing the bull's eye of the 123I-pPPA study by the bull's eye of resting 99mTc-Sestamibi, and its maximum value was normalized to 100%.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1451705

Kuikka, J T; Mussalo, H; Hietakorpi, S; Vanninen, E; Länsimies, E

1992-01-01

267

An experimental animal model of chronic myocardial hibernation: comparative study of cine-MR, myocardial single photon emission computed tomography and pathology  

International Nuclear Information System (INIS)

Objective: To establish the chronic low-flow myocardial hibernation animal model in pigs, and to assess the diagnostic value for myocardial hibernation by using various imaging methods. Methods: A total of 13 miniswine (30-40 kg) were used. All animals underwent general anesthesia and orotracheal intubation while the animals were mechanically ventilated. Under sterile conditions, left ventriculography and coronary angiography were performed by introduction of catheter into the right femoral artery. Further, a left anterolateral thoracotomy was performed in the third intercostal space. The proximal LCX was dissected free to allow placement of an ameroid constrictor. More than 1 month later, left ventriculography and coronary angiography were performed again, followed by cine-MRI at rest and during stress with low-dose of dobutamine (5?g·kg-1·min-1), respectively. Traditional and/or breath-hold cine-MRI were used to evaluate regional left ventricular wall motion, corresponding to basal, midventricular and apical short-axis tomograms. Regional wall motion score index (WMSI) was calculated. At the same time 99mTc-MIBI myocardial SPECT was performed at rest and during nitroglycerin administration, respectively. All animals were finally sacrificed for pathological examination. Triphenyl tetrazolium chloride (TTC) staining was used to assess the myocardial infarction. Electron microscopy was used to identify myocardial cellular changes chadentify myocardial cellular changes characteristic of hibernating myocardium. Results: Three pigs died during surgery or within two weeks after surgery. One pig died of anesthesia during SPECT examination, 1 pig suffered from aneurysm, and another one pig showed negative findings. The other 7 pigs were found with hypokinetic (n=4) or akinetic (n=3) myocardial regions related to stenosed LCX (70%-99%). Resting cine-MRI demonstrated decreased regional motion of the lateral and posteroinferior walls (ischemic regions) of the left ventricle (n=7), compared with the nonischemic anteroseptal regions; but the low dose dobutamine (5?g·kg-1·min-1) could recover those hypokinetic or akinetic myocardial regions, characteristic of hibernating myocardium. Resting 99mTc-MIBI myocardial SPECT (n=6) showed a fixed perfusion defect on the corresponding ischemic areas, which became reversible on the nitrate-augmented myocardial perfusion imaging. It also indicated myocardial viability presented at the ischemic areas. TTC staining revealed patchy infarction of the area-at-risk localized to the endocardial surface (n=3), and no myocardial infarction (n=4). Electron microscopy of sections from the hibernating regions revealed loss of contractile materials, increased numbers of small mitochondria, and glycogen accumulation within viable cardiomyocytes, which had been described as hallmarks of hibernating myocardium. Conclusion: Chronic low-flow myocardial hibernation can be reproduced in an animal model during progressive coronary stenosis caused by ameroid constrictor

268

201Tl to 67Ga crude uptake ratio in primary lung cancer with reference to histological type  

International Nuclear Information System (INIS)

201Tl to 67Ga Crude Uptake Ratio (CUR) was measured in 40 patients with primary lung cancer using quantitative 201Tl and 67Ga scans, and their CURs were compared with histological types. After regions of interest (ROIs) were set on the tumor and the normal lung, the mean counts (T: at the tumor, N: at the normal lung) for ROIs were measured on both scans, and the CUR of 201Tl to 67Ga (both crude uptakes: T-N/N) was calculated on the same patients. Seventeen adenocarcinomas had a high CUR of 1.82+-1.27, many of them taking up more 201Tl than 67Ga. Fourteen epidermoid carcinomas had a significantly lower CUR of 0.41+-0.25 than adenocarcinoma (p67Ga than 201Tl. Compared with adenocarcinomas, 3 oat cell carcinomas also had a significantly lower CUR of 0.40+-0.07 (p67Ga uptake greater than 201Tl uptake (CUR LT 0.80). Group II, no definite difference between two uptakes (0.80201Tl uptake greater than 67Ga uptake (CUR>=1.25). Many epidermoid carcinomas and small cell carcinomas belonged to Groupnd small cell carcinomas belonged to Group I, whereas many adenocarcinomas belonged to Group III. Furthermore, the 40 patients showed a continuous distribution from low-CUR epidermoid carcinoma to high-CUR adenocarcinoma. It was found that the measurement of 201Tl to 67Ga Crude Uptake Ratio by tumors enables not only a quantitative estimation of lung cancer but a presumption of various histogeneses in lung cancer. (author)

269

Initial multicentre experience of high-speed myocardial perfusion imaging: comparison between high-speed and conventional single-photon emission computed tomography with angiographic validation  

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High-speed (HS) single-photon emission computed tomography (SPECT) with a recently developed solid-state camera shows comparable myocardial perfusion abnormalities to those seen in conventional SPECT. We aimed to compare HS and conventional SPECT images from multiple centres with coronary angiographic findings. The study included 50 patients who had sequential conventional SPECT and HS SPECT myocardial perfusion studies and coronary angiography within 3 months. Stress and rest perfusion images were visually analysed and scored semiquantitatively using a 17-segment model by two experienced blinded readers. Global and coronary territorial summed stress scores (SSS) and summed rest scores (SRS) were calculated. Global SSS {>=}3 or coronary territorial SSS {>=}2 was considered abnormal. In addition the total perfusion deficit (TPD) was automatically derived. TPD >5 % and coronary territorial TPD {>=}3 % were defined as abnormal. Coronary angiograms were analysed for site and severity of coronary stenosis; {>=}50 % was considered significant. Of the 50 patients, 13 (26 %) had no stenosis, 22 (44 %) had single-vessel disease, 6 (12 %) had double-vessel disease and 9 (18 %) had triple-vessel disease. There was a good linear correlation between the visual global SSS and SRS (Spearman's {rho} 0.897 and 0.866, respectively; p < 0.001). In relation to coronary angiography, the sensitivities, specificities and accuracies of HS SPECT and conventional SPECT by visual assessment were 92 % (35/38), 83 % (10/12) and 90 % (45/50) vs. 84 % (32/38), 50 % (6/12) and 76 % (38/50), respectively (p < 0.001). The sensitivities, specificities and accuracies of HS SPECT and conventional SPECT in relation to automated TPD assessment were 89 % (31/35), 57 % (8/14) and 80 % (39/49) vs. 86 % (31/36), 77 % (10/13) and 84 % (41/49), respectively. HS SPECT allows fast acquisition of myocardial perfusion images that correlate well with angiographic findings with overall accuracy by visual assessment better than conventional SPECT. Further assessment in a larger patient population may be needed to confirm this observation. (orig.)

Neill, Johanne [University College London Hospital, Institute of Nuclear Medicine, London (United Kingdom); The Prince Charles Hospital, Brisbane (Australia); Prvulovich, Elizabeth M.; Bomanji, Jamshed B. [University College London Hospital, Institute of Nuclear Medicine, London (United Kingdom); Fish, Matthews B. [Sacred Heart Medical Center (SHMC), Springfield, OR (United States); Berman, Daniel S.; Slomka, Piotr J. [Cedars-Sinai Medical Center, Los Angeles, CA (United States); Sharir, Tali [Procardia Maccabi Healthcare Services (PMHS), Tel Aviv (Israel); Martin, William H. [Vanderbilt University Medical Center (VUMC), Nashville, TN (United States); DiCarli, Marcelo F. [Brigham and Women' s Hospital (BWH), Boston, MA (United States); Ziffer, Jack A. [Baptist Hospital of Miami (BHM), Miami, FL (United States); Shiti, Dalia [Spectrum-Dynamics, Caesarea (Israel); Ben-Haim, Simona [University College London Hospital, Institute of Nuclear Medicine, London (United Kingdom); Chaim Sheba Medical Center, Department of Nuclear Medicine, Tel-Hashomer (Israel)

2013-07-15

270

Correlation of myocardial perfusion single photon emission computed tomography with coronary artery calcium score in coronary artery disease- An Indian perspective  

International Nuclear Information System (INIS)

Full text: Objectives: The consequences of atherosclerosis can be detected by coronary artery calcium score (CACS) and stress induced myocardial ischemia on myocardial perfusion single photon emission computed tomography (MPS). We assessed the relationship between stress induced myocardial ischemia on (MPS) and magnitude of CACS by 64 slice computed tomography (CT) in patients undergoing both tests. Methods: Our study included 59 patients with no earlier history of coronary artery disease (CAD) of both sexes (males-47, females-12) in age group of 34-69 years. Our patients were referred by cardiologists after they underwent CACS. Of these 37 patients (63%) presented with symptoms which included chest pain (non-anginal, anginal, atypical) presence or absence of shortness of breath, and rest (37%) were asymptomatic. For each patient coronary risk factors were noted. All these patients underwent CACS and rest and stress MPS one-day protocol with Tc99m sestamibi within 7 days. According to CACS and symptoms, patients were divided into four groups, group A - asymptomatic 100 n=13, group D - symptomatic >100 (n=11). The incidence of inducible ischemia in MPS was compared to the magnitude of CACS abnormality. Results: There were 21 patients (36%) with ischemic MPS. According to groups, group A - 11%(n=1), groupB- 38%(n=10), groupC- 30%(n=4) and group D- 54%(n=6) had ischemic MPS. From the above we observed thathemic MPS. From the above we observed that incidence of ischemic MPS is more with increasing CACS. And also it is noted that it is more frequent in patients who presented with symptoms irrespective of CACS who are at short-term risk. In negative MPS, CACS may be useful in long term risk stratification in finding out subclinical atherosclerosis. Conclusion: The general perception is that the CACS is a good tool for long-term risk stratification but it may be applicable to those patients with no significant risk factors. When there are risk factors MPS is a better indicator for risk stratification for CAD irrespective of CACS. Further studies incorporating prognostic follow- up are required. (author)

271

Indications and evaluation of coronary artery bypass grafting with myocardial single photon emission tomography using 123I-BMIPP. A new tracer of myocardial metabolism of fatty acid  

International Nuclear Information System (INIS)

To evaluate viability and severity of ischemically damaged myocardium,myocardal single emission tomography (SPECT) using 123I-BMIPP (BMIPP), a new tracer of myocardial metabolism of fatty acid, was performed before and after coronary artery bypass grafting (CABG). 201TI myocardial SPECT (TI) and left ventriculography (LVG) were also used.Thirty-three revascularized areas in eight patients were investigated. Areas showing good redistribution on TI and normal uptake on BMIPP indicated good viability and simple ischemic myocardium. Postoperative uptake of both tracers returned to normal levels. Areas showing good redistribution on TI and severely decreased uptake on BMIPP indicated jeopardized myocardium with severe ischemia. All such areas were seen in patients with unstable angina.Postoperative uptake of both tracers returned to normal levels. Areas showing poor redistribution or severely decreased uptake on TI and slight uptake on BMIPP indicating hibernating areas. Postoperative uptake became normal or better than preoperative uptake on TI necrosis. However on BMIPP, the uptake was unchanged or recovered slightly. Areas showing complete defect in TI and BMIPP indicated necrosis and had no viabilty. Postoperatively the defect in both tracers were unchanged. Therefore, these areas required no revascularization. The ischemic state of myocardium could be assessed by evaluation of uptake patterns of BMIPP and TI using myocardial SPECT. Therefore, using this new tracer of PECT. Therefore, using this new tracer of myocardial fatty acid metabolism 'BMIPP' is useful for deciding culprit and viable lesions requiring coronary revascularization and evaluating therapeutical effects

272

Comparison of serum thyroglobulin, 131I and 201Tl scintigraphy in the postoperative follow-up of differentiated thyroid cancer  

International Nuclear Information System (INIS)

To evaluate the significance of 201Tl scintigraphy, 131I scintigraphy and serum thyroglobulin (Tg) levels in the postoperative follow-up of differentiated thyroid carcinoma, 86 patients were examined. Serum Tg was found to have the highest sensitivity (97%) as well as specificity (100%) for the detection of local tumour or metastases. Sensitivity and specificity of 131I scintigraphy after a therapeutic dose of 6100 MBq were 77 and 98%, respectively. For a diagnostic dose of 185 MBq 131I, sensitivity and specificity were 57 and 98%; for 74 MBq 201Tl these figures were 55 and 91%, respectively. The combination of serum Tg and 131I had a sensitivity of 100% and a specificity of 98% to detect the presence, although not always the localization, of persistent or recurrent tumour. 201Tl scintigraphy can provide useful additional information about the localization of local recurrences and metastases, especially in cases where serum Tg becomes positive and 131I uptake is absent. One has to bear in mind the possibility of discrepant results of 131I and 201Tl scintigraphy, in different tumour sites in one patient. There appeared to be no specific tendency for differential uptake of 131I versus 201Tl in relation to tumour type (papillary versus follicular) or localization with the possible exception of a higher preference for 131I uptake ier preference for 131I uptake in cases of micrometastases of papillary cancer in the lungs. (author)

273

Regional wall thickening in gated myocardial perfusion SPECT in a Japanese population: effect of sex, radiotracer, rotation angles and frame rates  

Energy Technology Data Exchange (ETDEWEB)

Gated single-photon emission computed tomography (SPECT) imaging of myocardium by {sup 99m}Tc and {sup 201}Tl is used extensively to measure quantitative cardiac functional parameters. However, factors affecting normal values for myocardial functional parameters and population-specific standards have not yet been established. The aim of the study was to determine the effect of sex, radiotracer, rotation angles and frame rates on resting myocardial wall thickening (WT) and to develop a Japanese standard of normal values for WT. Data from a total of 202 patients with low possibility of having cardiac problems were collected from nine hospitals throughout Japan. Patients were divided into five groups according to study protocol, and WT was evaluated according to the 17-segment and four-region (basal, mid and apical regions and the apex) polar map distribution. WT was generally higher in women than in men irrespective of the use of radiotracers, rotation angles or frame rates, and the difference was highly significant in the mid and apical regions. In any protocol used, resting myocardial thickening in the apex was higher than in the mid and apical regions, and thickening was lowest in the basal region, suggesting heterogeneous regional myocardial thickening (%) in normal subjects. Different rotation angles showed no significant change on WT, but different frame rates and tracers showed significant WT change in both sexes. Percent thickening of the myocardium was significantly higher in imaging by {sup 99m}Tc-labelled tracers than in {sup 201}Tl. Sex, radiotracers and frame rates had a significant effect on myocardial thickening, and the importance of population-specific standards should be emphasized. A normal database can serve as a standard for gated SPECT evaluation of myocardial thickening in a Japanese population and might be applicable to Asian populations having a similar physique. (orig.)

Akhter, Nasima; Nakajima, Kenichi; Okuda, Koichi; Matsuo, Shinro; Yoneyama, Tatsuya; Taki, Junichi; Kinuya, Seigo [Kanazawa University Hospital, Department of Nuclear Medicine, Kanazawa, Ishikawa (Japan)

2008-09-15

274

Removal of {sup 99m}Tc and {sup 201}Tl by means of Lemna Gibba; Remocion de {sup 99m}Tc y {sup 201}Tl mediante Lemna Gibba  

Energy Technology Data Exchange (ETDEWEB)

In this work the capacity of the water macrophyte Lemna gibba coming from San Pedro Tultepec in the Mexico State was studied to remove the radioisotopes {sup 99m}Tc and {sup 201}Tl, in order to show the capacity of this macrophyte for to treat some radioactive waste flowing that could contain this radioisotopes type. The removal capacity of {sup 99m}Tc and {sup 201}Tl of the macrophyte Lemna gibba was determined using the batch method. In accordance with the values of the obtained K{sub d}, the Lemna gibba with a size of particle diameter among 1mm - 300 {mu}m presents a better adsorption of {sup 99m}Tc. The {sup 201}Tl is adsorbed better in the bioadsorbent when it has a size of particle diameter <150{mu}m. (Author)

Fernandez R, E.; Carreno de L, M. C.; Cuevas S, J. C.; Hernadez T, U. O. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Fraccionamiento La Virgen, 52149 Metepec, Estado de Mexico (Mexico); Monroy G, F., E-mail: edelmiraf@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2012-10-15

275

Parathyroid localizlation by sup 201 Tl- sup 99m Tc subtraction scintigraphy; Results in secondary hyperparathyroidism  

Energy Technology Data Exchange (ETDEWEB)

Subtraction scintigraphy with {sup 201}Tl and {sup 99m}Tc for parathyroid localization was performed preoperatively in 13 patients with chronic renal failure and secondary hyperparathyroidism. Twenty of the 37 examined pathological glands were predicted correctly (sensitivity 54%). In 3 patients with recurrent hyperparathyroidism after surgery all pathological glands found at second operation had been detected correctly by subtraction scintigraphy. We conclude that this localization method has a limited value when used prior to first neck exploration in secondary hyperparathyroidism. In persistent hyperparathyroidism after surgery it may play a useful role in localizing missed and ectopic glands. (author).

Rademaker, P. (Department of Internal Medicine, University Hospital, Groningen (Netherlands)); Meijer, S. (Division of Nephrology, University Hospital, Groningen (Netherlands)); Piers, D.A. (Department of Nuclear Medicine, University Hospital, Groningen (Netherlands))

1990-01-01

276

Parathyroid localizlation by 201Tl-99mTc subtraction scintigraphy  

International Nuclear Information System (INIS)

Subtraction scintigraphy with 201Tl and 99mTc for parathyroid localization was performed preoperatively in 13 patients with chronic renal failure and secondary hyperparathyroidism. Twenty of the 37 examined pathological glands were predicted correctly (sensitivity 54%). In 3 patients with recurrent hyperparathyroidism after surgery all pathological glands found at second operation had been detected correctly by subtraction scintigraphy. We conclude that this localization method has a limited value when used prior to first neck exploration in secondary hyperparathyroidism. In persistent hyperparathyroidism after surgery it may play a useful role in localizing missed and ectopic glands. (author)

277

Metabolic myocardial viability assessment with iodine 123-16-iodo-3-methylhexadecanoic acid in recent myocardial infarction: comparison with thallium-201 and fluorine-18 fluorodeoxyglucose  

Energy Technology Data Exchange (ETDEWEB)

This study was performed to assess the value of 16-iodo-3-methylhexadecanoic acid (MIHA) as a marker of the residual cellular metabolism by comparison with FDG in patients with a recent myocardial infarction, and to evaluate its contribution compared with the {sup 201}Tl stress-redistribution-reinjection technique. Stress-redistribution-reinjection {sup 201}Tl imaging, rest MIHA imaging and glucose-loaded FDG imaging were performed in 22 patients with recent myocardial infarction. Out of the 628 myocardial segments obtained from the left ventricular analysis, 400 were hypoperfused, 177 of which were severely hypoperfused. Receiver operating characteristic (ROC) curves for predicting metabolic myocardial viability with FDG were derived from the results in respect of (a) {sup 201}Tl activity during exercise, redistribution and reinjection and (b) MIHA uptake, using the two FDG thresholds most commonly considered to define metabolic viability (0.50 and 0.60). Analysis of the 400 hypoperfused segments demonstrated that {sup 201}Tl reinjection was the most accurate test in predicting the presence of myocardial viability (area under the ROI curves=0.85 and 0.86 at the 0.50 and 0.60 FDG thresholds, respectively; P<0.05 vs other tests). The global predictive values of MIHA and {sup 201}Tl reinjection were, respectively, 0.87 and 0.89 at the 0.50 FDG threshold (NS), and 0.82 and 0.87 at the 0.60 FDG threshold (NS). When only the 177 severely hypoperfused segments were considered, {sup 201}Tl reinjection remained the most accurate test, while the accuracy of MIHA decreased significantly (0.78 at the 0.50 FDG threshold and 0.73 at the 0.60 FDG threshold, P<0.05 vs {sup 201}Tl reinjection). In all circumstances, MIHA was less specific than {sup 201}Tl reinjection for the detection of metabolic viability. (orig./MG). With 2 figs., 4 tabs.

Vanzetto, G. [Clinique Cardiologique, Centre Hospitalier Universitaire, Universite de Grenoble, Grenoble (France); Janier, M. [Centre d`Exploration et de Recherche Medicale par Emission de Positrons - CERMEP, Lyon (France); Fagret, D. [Service de Medecine Nucleaire, Centre Hospitalier Universitaire, Universite de Grenoble, Grenoble (France)]|[Laboratoire d`Etude des Radiopharmaceutiques URA CNRS 1287 - Universite de Grenoble, Grenoble (France); Cinotti, Luc [Centre d`Exploration et de Recherche Medicale par Emission de Positrons - CERMEP, Lyon (France); Andre-Fouet, X. [Centre d`Exploration et de Recherche Medicale par Emission de Positrons - CERMEP, Lyon (France); Comet, M. [Service de Medecine Nucleaire, Centre Hospitalier Universitaire, Universite de Grenoble, Grenoble (France)]|[Laboratoire d`Etude des Radiopharmaceutiques URA CNRS 1287 - Universite de Grenoble, Grenoble (France); Machecourt, J. [Clinique Cardiologique, Centre Hospitalier Universitaire, Universite de Grenoble, Grenoble (France)

1997-02-01

278

Value of myocardial defect size measured by thallium-201 SPECT: results of a multicenter trial comparing heparin and a new fibrinolytic agent  

International Nuclear Information System (INIS)

In a multicenter randomized double-blind trial comparing heparin and a new fibrinolytic agent, anisoylated plasminogen streptokinase activator complex (APSAC), 231 patients presenting with a less than 5 hr acute myocardial infarction underwent a contrast angiography (CA) before the end of the first week of admission, and radionuclide cardiac blood-pool imaging and a 201Tl single photon emission computed tomography (SPECT) study before the end of the third week. Left ventricular ejection fraction (LVEF) and a wall motion score (WM) were calculated from CA. LVEF was also obtained from cardiac blood-pool imaging, and defect size (DS) from 201Tl SPECT. Results demonstrated that all parameters were significantly improved in patients treated with APSAC versus heparin (contrast LVEF 53 +/- 13 vs. 47 +/- 14 p less than 0.01, WM 9.8 +/- 6.5 vs. 13.3 +/- 7.9 p less than 0.001, radionuclide LVEF 43 +/- 12 vs. 40 +/- 13 p less than 0.05, DS 14 +/- 12 vs. 18 +/- 14 p less than 0.05). When the patients were divided according to infarct site and infarct-related coronary artery patency, it was demonstrated with all four parameters that the beneficial effect of APSAC can be largely explained by the lower incidence of vessel obstruction in this group (37% vs. 77% in the heparin group, p less than 0.001). It is concluded that (a) when compared with heparin and in the conditions of the trial, APSAC significantly improves the cardiac function and decreases the DS and (b) DS measured by 20decreases the DS and (b) DS measured by 201Tl SPECT is as valuable a quantitative parameter of therapeutic evaluation as are LVEF and WM

279

Value of myocardial defect size measured by thallium-201 SPECT: results of a multicenter trial comparing heparin and a new fibrinolytic agent  

Energy Technology Data Exchange (ETDEWEB)

In a multicenter randomized double-blind trial comparing heparin and a new fibrinolytic agent, anisoylated plasminogen streptokinase activator complex (APSAC), 231 patients presenting with a less than 5 hr acute myocardial infarction underwent a contrast angiography (CA) before the end of the first week of admission, and radionuclide cardiac blood-pool imaging and a 201Tl single photon emission computed tomography (SPECT) study before the end of the third week. Left ventricular ejection fraction (LVEF) and a wall motion score (WM) were calculated from CA. LVEF was also obtained from cardiac blood-pool imaging, and defect size (DS) from 201Tl SPECT. Results demonstrated that all parameters were significantly improved in patients treated with APSAC versus heparin (contrast LVEF 53 +/- 13 vs. 47 +/- 14 p less than 0.01, WM 9.8 +/- 6.5 vs. 13.3 +/- 7.9 p less than 0.001, radionuclide LVEF 43 +/- 12 vs. 40 +/- 13 p less than 0.05, DS 14 +/- 12 vs. 18 +/- 14 p less than 0.05). When the patients were divided according to infarct site and infarct-related coronary artery patency, it was demonstrated with all four parameters that the beneficial effect of APSAC can be largely explained by the lower incidence of vessel obstruction in this group (37% vs. 77% in the heparin group, p less than 0.001). It is concluded that (a) when compared with heparin and in the conditions of the trial, APSAC significantly improves the cardiac function and decreases the DS and (b) DS measured by 201Tl SPECT is as valuable a quantitative parameter of therapeutic evaluation as are LVEF and WM.

Maublant, J.C.; Peycelon, P.; Cardot, J.C.; Verdenet, J.; Fagret, D.; Comet, M.

1988-09-01

280

Effects of low-dose dobutamine on left ventricular function in normal subjects as assessed by gated single-photon emission tomography myocardial perfusion studies  

Energy Technology Data Exchange (ETDEWEB)

Electrocardiography gated single-photon emission tomography (gated SPET) allows the assessment of regional perfusion and function simultaneously and in full spatial congruency. In this study changes in global and regional left ventricular function in response to dobutamine infusion were assessed in ten healthy volunteers using sequential gated SPET myocardial perfusion acquisitions. Four consecutive gated SPET images were recorded 60 min after injection of 925 MBq technetium-99m tetrofosmin on a three-head camera equipped with focussing collimators. Two acquisitions were made at rest (baseline 1 and 2), and the third and fourth acquisitions were started 5 min after the beginning of the infusion of 5 and 10 {mu}g kg{sup -1} min{sup -1} dobutamine, respectively. Systolic wall thickening (WT) was quantified using a method based on circumferential profile analysis. Left ventricular ejection fraction (LVEF) and volumes were calculated automatically using the Cedars-Sinai program. Nine of the ten subjects presented a definite increase in WT during dobutamine infusion. WT increased on average from 46%{+-}14% at baseline to 71%{+-}23% (range: 37%-106%; P<0.05) during 5 {mu}g kg{sup -1} min{sup -1} dobutamine infusion and to 85%{+-}25% (range: 62%-123%; P<0.05 with respect to WT at 5 {mu}g kg{sup -1} min{sup -1}) during 10 {mu}g kg{sup -1} min{sup -1} dobutamine infusion. Apical segments showed the largest WT at baseline. The average WT response to dobutamine was similar for all parts of the myocardium. It is concluded that changes in WT induced by infusion of low-dose dobutamine can be assessed by sequential gated SPET myocardial perfusion studies. The ''stress gated SPET'' protocol proposed in this study might be helpful to distinguish viable from scar tissue in patients with coronary artery disease, by demonstrating a preserved inotropic response in hypoperfused myocardium. (orig.)

Everaert, H.; Vanhove, C.; Franken, P.R. [Div. of Nuclear Medicine, University Hospital, Free University of Brussels (Belgium)

1999-10-01

 
 
 
 
281

Detection of myocardial viability by means of Single Proton Emission Computed Tomography (Perfused SPECT) dual 201 Tl (rest of 15 minutes, 24 late hours and 24 hours reinjection) and gated-SPECT 99m Tc-SESTAMIBI in effort or stimulation of the coronary reserves  

International Nuclear Information System (INIS)

The objective of this work was to determine if the images of SPECT 201 TI in rest of 15 minutes, 24 late hours and Gated-SPECT 99m Tc-SESTAMIBI in effort or stimulation of coronary reservation correlate with the study of 24 hours post reinjection of 201TI to determine the presence of having knitted viable myocardium. Material and methods: 29 patients were studied with coronary arterial illness (EAC) to who are carried out SPECT 201 TI in rest with images of 15 minutes, 24 late hours and 24 hours reinjection, by means of the administration of 201TI to dose of 130 MBq and reinjection with 37 MBq. and Gated-SPECT 99mTc-SESTAMIBI in effort or stimulation of coronary reservation, later to the administration of 1110 MBq. Results: 29 patients were included according to inclusion approaches and exclusion, of those which 22 (75.86%) they correspond at the masculine sex and 7 (24.13%) to the feminine one, with an average of 62.1 year-old age, 2320 segments myocardial were analysed so much it is phase post-effort as rest; they were diagnosed a total of 264 segments with heart attack, of which viability myocardium was observed in 174 segments. The statistical tests are analysis of frequencies. The non parametric test of Wilcoxon and Mann-Whitney. Conclusions: the viability myocardial at the 24 late hours and 24 hours reinjection was similar; significant difference exists between the study of 15 minutes and 24 hourstween the study of 15 minutes and 24 hours reinjection, ischemic illness was also demonstrated in territories different to the heart attack area in the studies of 15 minutes, late 24 hours and 24 hours reinjection. (Author)

282

Discrimination capabilities of fine- needle aspiration combined with serum thyroglobulin and 201Tl scintigraphy of thyroid nodules  

International Nuclear Information System (INIS)

The sensitivity and N.P.V. by 201Tl scintigraphy which nodular uptake was higher and equal to normal thyroid tissue on early scan without quantitative washout were higher than those of FNA combined with the serum thyroglobulin level (sensitivity; 96.9%, 53.1-75.0%, N.P.V. 96.3%, 72.2-80.5%, respectively p201Tl scintigraphy is more useful for discrimination of benign and malignant thyroid nodules than fine- needle aspiration combined with serum thyroglobulin. (author)

283

Preparation and evaluation of [201Tl](III)-DTPA complex for cell labeling  

International Nuclear Information System (INIS)

Due to interesting physical properties and wide availability of 201Tl as a SPECT radionuclide, the incorporation of this nuclide into DTPA for cell labeling was targeted. Thallium-201 (T1/2 = 3.04 d) in Tl+ form was converted to Tl3+ cation in the presence of O3/6M HCl and di-isopropyl ether, controlled by RTLC/gel electrophoresis methods. The final evaporated activity reacted with cDTPA in normal saline to yield [201Tl](III)DTPA at room temperature after 0.5 hour, followed by solid phase extraction purification using C18 Sep-Pak column (radiochemical yield >95%). Radiochemical purity of more than 99% was obtained using RTLC with specific activity of about 260 GBq/mmol. The stability of the tracer was checked in the final product in the presence of human serum at 37 deg C up to 3 days. The partition coefficient was also measured. The labeled compound was used in red blood cell (RBC) labeling. The cell uptake ratio was determined at 4, 25 and 37 deg C up to 3 hours. (author)

284

Estimation of internal radiation due to the administration of 201Tl  

International Nuclear Information System (INIS)

Today, radioactive pharmaceuticals are widely used for the purpose of diagnosis in the field of nuclear medicine, bringing many bits of useful information. On the other hand, radiation is known to be bionegative, having possibility of inducing stochastic effects such as cancers and genetic effects even in the relatively low dose region together with non-stochastic effects which could result from radiation exposure higher than threshold value. The authors have published a series of papers with regard to the estimation of radiation exposures for medical use based on three principles for radiation protection stated in the ICRP publication 26, i.e., the principles of justification, optimization and limitation. In this paper, radiation dose by a radiation worker due to 201Tl administration for the diagnosis of acardiac disease was evaluated based on the measurement of concentration of radioactive isotope excreted in urine over 1 month. Internal radiation dose due to the administration of 3 mCi (1.11x108 Bq) of 201Tl was estimated to be 610 mrem (6.1 mSv) which agreed well with the result reported by H.L. Atkins (1977) and far exceeded the occupational exposure (approximately 60 mrem over 12 years). The authors suggested the importance of reducing medical exposure. (author)

285

Usefulness of 99mTc-methoxy-iso-butyl-isonitrile myocardial single photon emission computed tomography during infusion of low-dose dobutamine and nitroglycerin. Evaluation of myocardial viability  

International Nuclear Information System (INIS)

This study evaluated myocardial viability with 99mTc-methoxy-iso-butyl-isonitrile (MIBI) single photon emission computed tomography (SPECT) during infusion of low-dose of dobutamine (DOB) and nitroglycerin (NTG). The subjects were 13 patients with coronary artery disease associated with wall motion abnormalities. Myocardial SPECT with MIBI was performed during infusion of NTG followed by infusion of DOB. Rest MIBI study was also performed on a separate day. The regional uptake of MIBI was visually evaluated by scoring (from 0=normal to 3=defect) in 9 regions of left ventricular wall in comparison with LVG or echocardiography data. The regional uptake of MIBI was quantitatively evaluated in 33 segments of left ventricular wall by a computer. The uptake of MIBI during infusion of both DOB and NTG was compared with that at rest study in the region of wall motion abnormalities. The mean uptake score of MIBI during infusion of both DOB and NTG and that of MIBI at rest was 1.8 and 2.1, respectively. The uptake of MIBI was significantly improved by infusion of both DOB and NTG (p<0.01). Percent of the peak activity of MIBI during infusion of both DOB and NTG and that of MIBI at rest in the region where the uptake score had been improved was 76.6±12.7% versus 74.0±13.1% (p<0.01). Percent of the peak activity of MIBI in the region where the uptake score had not been improved was 60.1±18.1% versus 60.7±18.7% (NS). Quantitative study also showed a significant impre study also showed a significant improvement of MIBI uptake on the study of DOB and NTG. These results suggest that MIBI SPECT during infusion of both DOB and NTG infusion might be useful for evaluating myocardial viability. (S.Y.)

286

Therapeutic effects of coenzyme Q10 on dilated cardiomyopathy. Assessment by {sup 123}I-BMIPP myocardial single photon emission computed tomography (SPECT). A multicenter trial in Osaka University Medical School Group  

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To evaluate therapeutic effects of Coenzyme Q10 (CoQ10), 15 patients with dilated cardiomyopathy were investigated by {sup 123}I-BMIPP myocardial single photon emission computed tomography (SPECT). The BMIPP defect score was determined semiquantitatively by using representative short and long axial SPECT images. Mean BMIPP defect score with CoQ10 treatment was significantly low, 7.7{+-}6.1 compared to 12.7{+-}7.4 without CoQ10 treatment. On the other hand, in 8 patients of dilated cardiomyopathy, % fractional shortening using echocardiography was not different before and after CoQ10 treatment. In conclusion, {sup 123}I-BMIPP myocardial SPECT was proved to be sensitive to evaluate the therapeutic effects of CoQ10, which improve myocardial mitochondrial function, in the cases of dilated cardiomyopathy. (author).

Nishimura, Tsunehiko; Hori, Masatsugu [Osaka Univ. (Japan). Faculty of Medicine

1996-01-01

287

Therapeutic effects of coenzyme Q10 on dilated cardiomyopathy. Assessment by 123I-BMIPP myocardial single photon emission computed tomography (SPECT). A multicenter trial in Osaka University Medical School Group  

International Nuclear Information System (INIS)

To evaluate therapeutic effects of Coenzyme Q10 (CoQ10), 15 patients with dilated cardiomyopathy were investigated by 123I-BMIPP myocardial single photon emission computed tomography (SPECT). The BMIPP defect score was determined semiquantitatively by using representative short and long axial SPECT images. Mean BMIPP defect score with CoQ10 treatment was significantly low, 7.7±6.1 compared to 12.7±7.4 without CoQ10 treatment. On the other hand, in 8 patients of dilated cardiomyopathy, % fractional shortening using echocardiography was not different before and after CoQ10 treatment. In conclusion, 123I-BMIPP myocardial SPECT was proved to be sensitive to evaluate the therapeutic effects of CoQ10, which improve myocardial mitochondrial function, in the cases of dilated cardiomyopathy. (author)

288

The value of gallium-67 and thallium-201 whole-body and single-photon emission tomography images in dialysis-related ?2-microglobulin amyloid  

International Nuclear Information System (INIS)

The aim of this study was to investigate the value of gallium-67 and thallium-201 whole-body and single-photon emission tomography (SPET) images in long-term dialysis patients in whom dialysis-related ?2-microglobulin amyloid (?2-MA) was clinically suspected. Twenty-three patients who had received dialysis for at least 10 years were included in the study. A technetium-99m methylene diphosphonate (MDP) whole-body scan was performed in all of the patients. If there was any MDP accumulation in the articular and/or peri-articular region, 67Ga and 201Tl whole-body and SPET images were then acquired. If any 67Ga and/or 201Tl uptake was observed, a CT-guided biopsy was done. In those patients who had articular and/or peri-articular uptake of 99mTc MDP, 67Ga and/or 201Tl and who were pathologically proven to have ?2-MA, 99mTc MDP, 67Ga and 201Tl whole-body scans and SPET were carried out again, both 3 months and 1 year after initiation of treatment. This served to evaluate the therapeutic effect and allowed comparison with the clinical findings. Of the 23 patients, eight had abnormal 99mTc MDP uptake. Among these eight, six had intense 99mTc MDP, 67Ga and 201Tl uptake in the articular and peri-articular regions before medication. Three months after the start of treatment, there were very me start of treatment, there were very marked decreases in uptake on both the 67Ga and 201Tl scans but less obvious changes in uptake of 99mTc-MDP. In comparison with the other clinical manifestations such as limitation in range of motion, the more the painful disability improved, the less was the uptake on both 67Ga and 201Tl scans. There were virtually no differences in uptake pattern between the three scans of each radiopharmaceutical obtained for each patient in both 3 months and 1 year after initial of treatment. It is concluded that 99mTc-MDP whole-body bone scan can both detect active and pre-existing inactive deposits of ?2-MA. 67Ga and 201Tl scans are helpful to differentiate active from inactive deposits of ?2-MA and to evaluate the therapeutic effect on these patients. SPET images are usually needed to distinguish articular and peri-articular lesions from bone lesions. (orig.)

289

201Tl SPECT for evaluation of brain tumors as compared with 123I-IMP SPECT and 18F-FDG PET  

International Nuclear Information System (INIS)

Clinical usefulness of 201Tl SPECT for evaluation of brain tumors was studied in comparison with 123I-IMP SPECT and 18F-FDG PET. 201Tl SPECT and 123IMP SPECT were performed in 73 patients with brain neoplasm (group 1) and 15 patients with non-tumor cerebral diseases (group 2). Among them, 31 patients in group 1 and 5 patients in group 2 received 18F-FDG PET. SPECT was done with a ring type machine (HEADTOME SET011) and PET with a neuro PET (PCT H1). Forty-eight of 73 (65.8%) patients in group 1 showed increased accumulation of 201Tl in tumor site, whereas only 9 (12.3%) patients showed increased radioactivity of 123I-IMP in the lesion. Eighteen of 31 (58.1%) patients with neoplasm demonstrated increased regional cerebral metabolic rate of glucose (rCMRgl) in the lesion. Only two out of 15 (13.3%) patients with non-tumor lesion demonstrated increased accumulation of 201Tl. None of them showed accumulation of 123I-IMP or increased rCMRgl. Patients with malignant neoplasm demonstrated higher uptake of 201Tl in the lesion than those with benign neoplasm or non-tumor lesions. Post-therapeutic patients with glioblastoma or metastatic tumors showed lower 201Tl uptake than before therapy. Superimposed images of both 201Tl and 123I-IMP resemble rCMRgl functional images, suggesting increased 201Tl radioactivity in vreased 201Tl radioactivity in viable tumor tissue with decreased radioactivity in surrounding areas. 201Tl SPECT is useful for diagnosis of brain tumors and evaluation of effectiveness of therapy or evidence of residual tumor tissue. It may differentiate malignant tumors from benign tumors or non-tumor intracranial diseases including radiation injury and detect tumor recurrence earlier. (author)

290

Accuracy of preoperative pinhole subtraction single photon emission computed tomography for patients with primary and recurrent hyperparathyroidism in an endemic goiter area  

International Nuclear Information System (INIS)

Bilateral parathyroid exploration is still the standard therapeutic procedure for primary and recurrent hyperparathyroidism (HPTH). Since a unilateral surgical strategy that reduces surgical complications should not increase the risk of missing enlarged parathyroid glands, reliable preoperative imaging is the first requirement for this approach. This study was conducted to assess the accuracy of preoperative 99mTcO4-201Tl pinhole subtraction single photon emission computed tomography (SPECT) compared with sonography. The study population consisted of 15 patients with primary (n=13) or recurrent (n=2) HPTH who underwent preoperative 99mTcO4-201Tl pinhole subtraction SPECT. Preoperative sonography was also done in 14 of these patients. 99mTcO4-201Tl pinhole subtraction SPECT was significantly more accurate than sonography. It had an overall accuracy of 80% in detection of enlarged parathyroid glands. The accuracy of localization increased to 92.3% in patients with solitary adenomas, and to 100% in those with solitary adenomas and no previous parathyroid exploration. The high accuracy of preoperative localization with 99mTcO4-201Tl pinhole subtraction SPECT in patients with primary and recurrent HPTH allows for an imaging-guided unilateral operative strategy in most patients, even those with concomitant nodular goiters. This may reduce the rant nodular goiters. This may reduce the risk of surgical complications and expand the use of minimally invasive techniques in parathyroid surgery. (author)

291

Energy spectral analysis in a photopeak region of 201Hg X-rays for 201Tl imaging  

International Nuclear Information System (INIS)

For thallium-201 (201Tl) imaging, a photopeak of X-ray region of mercury-201 (201Hg) around 70 keV is usually employed. In such a low energy region, scatter and attenuation in the body become serious problems for quantitative scintigraphic imaging. We measured energy spectra around 201Hg X-ray region by a 201Tl line source with scattering materials and a gamma camera, and analyzed them to investigate the amount of scattered photons in 201Tl imaging window. Furthermore, Monte Carlo calculations were performed to distinguish primary photons from scattered photons. The results of analysis of energy spectra showed that the 201Hg X-ray photopeak consists of four different X-rays and do not have a perfect Gaussian shape. It was also found that not only forward scatter but also much backward scatter are included in this region. These scattered photons were reduced by using an off-peak window moved toward the higher energy region. We conclude that the data obtained from the analysis of scattered photons in 201Tl imaging window are very useful to develop a new scatter correction method and evaluate the scatter rejection methods proposed. (author)

292

Absorbed radiation to the nuclear medicine nurses from patients administered 201Tl and 99mTc- MIBI  

International Nuclear Information System (INIS)

People who have administrated radiopharmaceuticals could be a source of radiation to their relatives, medical nurses, and people who have contact them. In this study, the dose rates at various distances of 5, 10,50 and 100cm from 70 patients, who were administered diagnostic amounts of 201Tl-Chloride and 99mTc-MIBI, was measured using an ionization chamber. For determination of external radiation dose to the nurses the radiations in three deferent interval times have measured. The maximum values of external dose rates of 201Tl and 99mTc- MIBI were 11.2?Sv/h ±2.3 and 43.1?Sv/h ±11.9 respectively at 5cm from the patients. Significant exposure from patients after injection of 99mTc-MIBI was limited on the day of administration. Departure doses rate of 201Tl fell gradually so by 3 days after administration was significant. Maximum and average absorbed dose of nuclear medicine staff for one 201Tl scan was 4.6 and 2.7?Sv/h, and for 99mTc-MIBI was 18.1 and 9.8?Sv/h in a working day. (author)

293

Evaluation of 99mTc-ECD SPECT for the detection of brain tumor. Comparison with 201Tl SPECT  

International Nuclear Information System (INIS)

For the evaluation of brain tumor (n=15), we performed both dynamic and static 99mTc-ECD (ECD) SPECT studies. 201Tl SPECT was also used for comparison with the results of ECD SPECT. Dynamic ECD SPECT was obtained following the injection of 600 MBq of ECD. Five min after the injection of ECD, static ECD SPECT was performed. 201Tl SPECT was obtained 10 min after the injection of 74 MBq. Abnormal uptake was recognized in 7 of 15 tumors with dynamic ECD; 5 of 7 meningiomas, 1 of 1 glioblastoma and 1 of 1 astrocytoma. However, no abnormal uptake was seen in 3 of 3 benign tumors (1 low grade astrocytoma, 1 hemangioma, 1 craniopharyngioma) and in 2 of 2 brain metastases. In contrast abnormal uptake was seen in 11 of 15 tumors with 201Tl; 7 of 7 meningiomas, 2 of 2 brain metastases, 1 of 1 glioblastoma and 1 of 1 craniopharyngioma. No abnormal uptake was seen in 3 of 3 benign tumors (1 hemangioma and 2 low grade astrocytomas). Equivocal uptake was seen in 1 low grade astrocytoma with dynamic ECD and 201Tl. The mechanism of the accumulation of dynamic ECD to brain tumor is unclear. However, it may reflect not only blood flow, but also metabolism. (author)

294

Reverse redistribution in dipyridamole-loading thallium-201 images using single photon emission computed tomography  

International Nuclear Information System (INIS)

Dipyridamole was infused intravenously at a rate of 0.142 mg/kg per min for four min, and a stress image was obtained 10 min after the injection of two mCi 201Tl. The myocardial image of Tl was analyzed by single photon emission computed tomography and its washout rate was calculated by the segmental ROI method. Myocardial function and the motion of the left ventricular wall were analyzed by 99mTc-RBC-gated cardiac pool imaging. Reverse redistribution was noted in 27 (21.6 %) of 125 consecutive Tl dipyridamole and redistribution myocardial imaging studies. The stress image demonstrated normal perfusion (group 1) and reduced perfusion (group 2) of Tl. Group 1 consisted of 17 patients with diabetes mellitus, supraventricular arrhythmias, hypertension, and others. Group 2 consisted of 10 patients with subendocardial infarction, diabetes mellitus, and hypertension, and others. The percentage prevalence of reverse redistribution among patients with supraventricular arrhythmia was 62.5 % (five of eight patients), with subendocardial infarction 60.0 % (three of five), with hypertension 42.8 % (six of 14), and with diabetes mellitus 40.0 % (eight of 20), while in those with transmyocardial infarction and angina pectoris no reverse redistribution percentage was found. The washout rate of Tl in normal perfusion areas was 44.0 ± 12.8 %, the reverse redistribution of group 1 was 47.4 ± 12.8 %, and of group 2 was 51.2 ± 8.2 %. The washout rate of the rever ± 8.2 %. The washout rate of the reverse redistribution of group 2 was significantly greater than that of the normal areas. In gated cardiac pool imaging, patients in group 2 had significantly larger areas showing abnormal contraction of the left ventricular wall and significantly lower ejection fraction than did group 1. In the electrocardiogram ST segment depression was noted more frequently in group 2 than group 1. No Q wave was present in the corresponding reverse redistribution area. (J.P.N.)

295

A new classification of lung cancer from a nucleomedical viewpoint using quantitative 201Tl and 67Ga scans in relation to histological type  

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The possibility of nucleomedically classifying lung cancer was studied with quantitative 201Tl and 67Ga scans. Fundamental experiments with phantoms were performed to correct 201Tl and 67Ga uptake by tumors, and a clinical study based on these experiments was carried out on 31 patients with lung cancer. The classification of lung cancer was impossible by measuring either 201Tl uptake or 67Ga uptake alone, but was possible by calculating the Crude Uptake Ratio (CUR), the ratio of 201Tl uptake to 67Ga uptake by tumors on the same patients. Fifteen adenocarcinomas had a high CUR of 1.45 +- 0.77, many of them taking up more 201Tl than 67Ga. Nine epidermoid carcinomas had a CUR of 0.34 +- 0.25, significantly lower than adenocarcinomas (p67Ga than 201Tl. Two adenosquamous carcinomas had a CUR of 0.95 +- 0.19, intermediate between adenocarcinomas and epidermoid carcinomas. CURs varied greatly ranging from 0.03 to 4.31 and the 31 patients showed a continuous arrangement from low-CUR epidermoid carcinoma to high-CUR adenocarcinoma. The measurement of 201Tl and 67Ga uptake by the tumors was found to enable not only the nucleomedical classification but the presumption of various histogeneses in lung cancer. (author)

296

Usefulness and limitations of ECG-gated myocardial single-photon emission computed tomography with 99mTc-methoxy-isobutyl-isonitrile (MIBI) in patients with prior myocardial infarction  

International Nuclear Information System (INIS)

To evaluate the relationship between regional wall motion and 99mTc-methoxy-isobutyl-isonitrile (MIBI) uptake, ECG-gated single-photon emission computed tomography (SPECT) with 99mTc-MIBI was performed in 20 patients with prior myocardial infarction. The left ventricular images at end-diastole (ED) and end-systole (ES) were divided into 39 segments, respectively. Based on circumferential profile analysis, relative uptake (%EDc, %ESc), percent count increase (%?C), and normalized percent count increase (%?Cn) were analyzed in each segment and compared with regional wall motion indices assessed by echocardiography and left ventriculography. ECG-gated SPECT with 99mTc-MIBI provided high contrast tomograms of the left ventricular myocardium. %EDc and %ESc showed good correlations with regional wall motion indices. %?C and %?Cn, however, showed lower correlations compared with %EDc and %ESc. In conclusion, high-quality left ventricular images were obtained with 99mTc-MIBI ECG-gated SPECT, but quantitative analysis based on only percent count increase (%?C) have limitations for evaluation of regional wall motion. (author)

297

Development of a new chemical procedure for the production of the radiopharmaceutical 201TlCl  

International Nuclear Information System (INIS)

This paper presents the experimental results of thallium (III) extraction from chloro/acid solution with butyl acetate in hollow-fiber membrane contactors. The experiments were performed using laboratory made modules consisting of hydrophobic polyvinylidene fluoride fibers of different effective membrane areas. The aqueous phase was either recirculated between the module and a mixed reservoir, or flowed in continuous contact mode of operation, while the organic phase was fed at the shell side in once-through mode. The experimental results are discussed in terms of the extent of Tl (III) extracted from the aqueous phase. The results were used to estimate the optimal effective fiber length, required for the design of a hollow-fiber contractor based extraction process that can be utilized for the production of the radiopharmaceutical 201TlCl. (author)

298

Improved detection of fill-in using sublingual nitroglycerin in technetium-99m tetrofosmin exercise/rest single photon emission computed tomography one day protocol for old myocardial infarction  

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Twenty-one patients with old myocardial infarction underwent repeated 99mTc-tetrofosmin (99mTc) exercise/rest same day protocols with and without the administration of sublingual nitroglycerin (NTG) 5 min before the second injection of 99mTc for rest SPECT. Twelve of these patients also underwent ordinary exercise/redistribution 201Tl SPECT. The control study protocol images showed decreased uptake of 99mTc on exercise in 157 of 420 segments and the presence of fill-in at rest in 58 segments. Images obtained with administration of NTG showed decreased uptake of 99mTc on exercise in 163 of 420 segments and fill-in in 74 segments at rest. The frequency of fill-in was greater in the NTG protocol than in the control protocol. The segments were scored as different grades according to 99mTc uptake between 2 protocols. Fill-in was only present or more remarkable in 31 segments in the NTG protocol than in the control protocol. Fill-in was only present or more remarkable in 10 segments in the control protocol than in the NTG protocol. In the NTG protocol, the mean defect score of the exercise images, calculated from the bull's eye image automatically, was higher than that of the rest images. The mean severity score of the exercise images, also calculated from the bull's eye image automatically, was likewise higher than that of the rest images, whereas the mean severity score of the stress images and r severity score of the stress images and rest images in the control protocol was not significantly different. Moreover, the mean defect score and severity score of the rest images from the NTG protocol were significantly lower than those obtained from the control protocol. Sublingual NTG administration before the injection of 99mTc-tetrofosmin at the rest study in the one day exercise/rest studies enhanced fill-in, so may enhance the detection of viable myocardium, allowing more informed decisions regarding cardiac revascularization in patients with chronic coronary artery disease. (K.H.)

299

Evaluation of breath-hold 201Tl SPECT in the differential diagnosis of solitary pulmonary nodules  

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The aim of this study was to evaluate the usefulness of deep inspiration breath-hold SPECT (BrST, a method for 201Tl SPECT) in the diagnosis of solitary pulmonary nodules (SPN). Ten patients with malignant lesions and five with benign lesions were enrolled in this study. Early SPECT acquisition was performed 15 min after injection of 201Tl, while delayed SPECT images were acquired 3 h after injection. The first 15-sec acquisition was done using the BrST technique, and the second with the conventional free breathing (FB) method. We performed this technique alternately, and therefore, the odd data were from BrST and the even data were from FB. We referred to the ratio of the tumor uptake to the contralateral normal lung uptake (T/N ratio) of the early images as the early uptake ratio (ER) and to the T/N ratio of the delayed images as the delayed uptake ratio (DR). To semi-quantitatively evaluate the degree of retention in the lesion, the retention index (RI) was calculated. The RI of BrST indicated greater accuracy than that of FB in the differential diagnosis of SPN. For the benign and malignant lesions, the RI of BrST was -3.07±31.51 and 29.86±25.01, respectively (p<0.05). The sensitivity, specificity, and accuracy of BrST (80%, 80%, and 80%, respectively) were significantly higher than those of FB (p<0.05). The BrST method is more accurate than that of the conventional FB method in the differential diagnosis of SPN. (author)osis of SPN. (author)

300

Transient ischemic stunning of the myocardium in stress thallium-201 gated SPET myocardial perfusion imaging: segmental analysis of myocardial perfusion, wall motion and wall thickening changes  

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Prolonged and persistent myocardial stunning has recently been demonstrated using technetium-99m sestamibi gated single-photon emission tomography (SPET) myocardial perfusion imaging post exercise or pharmacological stress test. In this study, we investigated the early postischemic transient myocardial stunning on early and delayed poststress thallium-201 gated SPET myocardial perfusion imaging using segmental wall motion (WM) and wall thickening (WT) analysis. A total of 1,680 segments from 84 patients' studies (53 men and 31 women, mean age 60 years) were evaluated on both early and delayed thallium-201 gated SPET treadmill exercise (59) or dobutamine stress (25) myocardial perfusion imaging. Semiquantitative analysis of perfusion, WM and WT in all segments was performed by two observers. Segments were classified according to changes in WM and WT between early and delayed images into normal, fixed abnormality, or improved abnormality (transient stunning), and were further classified according to changes in perfusion into normal, fixed defects, or ischemic. There were significant correlations between perfusion and WM, perfusion and WT, and WM and WT segmental scores on both early and delayed images. Transient stunning was seen significantly (P<0.001) more often in ischemic segments than were normal or fixed perfusion defects using WM (58%) and WT (50%) assessments. There was also a significant correlation between the severity of ischemia and transient stunning with either WM (P<0.05) or WT (P<0.005) evaluation. Segmental myocardial contractility assessment from gated SPET {sup 201}Tl myocardial perfusion imaging using WM and WT was comparable, and results correlated well with the myocardial perfusion assessment. Early transient myocardial stunning was frequently observed in ischemic segments and was related to the severity of myocardial ischemia. (orig.)

Santiago, Jonas Francisco Y.; Heiba, Sherif I.; Abdel-Dayem, Hussein M. [Nuclear Medicine Service, Department of Radiology, St. Vincent' s Catholic Medical Centers of New York, 153 West 11 Street, New York, NY 10011 (United States); Jana, Suman [Department of Endocrinology, St. Vincent' s Catholic Medical Centers of New York (United States); Mirzaitehrane, Majid [Department of Cardiology, St. Vincent' s Catholic Medical Centers of New York (United States); Dede, Fuat [Nuclear Medicine Fellow, Turkish Science Foundation, Marmara University, Ankara (Turkey)

2002-08-01

 
 
 
 
301

A higher prevalence of abnormal regional cerebral blood flow in patients with syndrome X and abnormal myocardial perfusion  

International Nuclear Information System (INIS)

To test the hypothesis that syndrome X is a systemic vascular disorder, technetium-99m ethyl cysteinate dimer (Tc-99m ECD) brain single photon emission computed tomography (SPECT) was used to detect abnormal regional cerebral blood flow (rCBF) in 30 patients with syndrome X. These patients were separated into group 1, 20 patients with definite myocardial perfusion defects diagnosed by thallium-201 (Tl-201) myocardial perfusion SPECT; and group 2, 10 patients without any myocardial perfusion defects. Tc-99m ECD brain SPECT demonstrated hypoperfusion brain lesions in 95% (19/20) and 20% (2/10) of patients in groups 1 and 2, respectively. This difference in the cidence between the two groups was significant. In group 1 and 2 patients, parietal lobes were the most common hypoperfusion areas, while the cerebellum was the least common hypoperfusion area of the brain. Syndrome X is a systemic vascular disorder with a high incidence of hypoperfusion lesions of the brain based on the findings of Tc-99m ECD brain SPECT, and is usually coincident with myocardial defects based on the Tl-201 myocardial perfusion SPECT findings. (author)

302

Utilidad de la tomografía computarizada de emisión de fotón único sincronizada con el electrocardiograma para la detección de isquemia miocárdica silente en diabéticos tipo 2 / Gated single photon emission computer tomography for the detection of silent myocardial ischemia  

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Full Text Available SciELO Chile | Language: Spanish Abstract in spanish [...] Abstract in english Background: Asymptomatic patients with severe coronary atherosclerosis may have a normal resting electrocardiogram and stress test. Aim: To assess the yield of Gated Single Photon Emission Computer Tomography (SPECT) for the screening of silent myocardial ischemia in type 2 diabetic patients. Materi [...] al and methods: Electrocardiogram, stress test and gated-SPECT were performed on 102 type 2 diabetic patients aged 60 ± 8 years without cardiovascular symptoms. AH subjects were also subjected to a coronary angiography whose results were used as gold standard. Results: Gated-SPECT showed myocardial ischemia on 26.5% of studied patients. The sensibility, specifity accuracy, positive predictive value and negative predictive value were 92.3%, 96%, 95%, 88.8%, 97.3%, respectively. In four and six patients ischemia was detected on resting electrocardiogram and stress test, respectively. Eighty percent of patients with doubtful resting electrocardiogram results and 70% with a doubtful stress test had a silent myocardial ischemia detected by gated-SPECT There was a good agreement between the results of gated-SPECT and coronary angiography (k =0.873). Conclusions: Gated-SPECT was an useful tool for the screening of silent myocardial ischemia.

Yamilé, Peña Q; Marco Antonio, Coca P; Juan Felipe, Batista C; José, Fernández-Britto R; Rodobaldo, Quesada P; Andria, Peña C.

1023-10-01

303

Utilidad de la tomografía computarizada de emisión de fotón único sincronizada con el electrocardiograma para la detección de isquemia miocárdica silente en diabéticos tipo 2 Gated single photon emission computer tomography for the detection of silent myocardial ischemia  

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Full Text Available Background: Asymptomatic patients with severe coronary atherosclerosis may have a normal resting electrocardiogram and stress test. Aim: To assess the yield of Gated Single Photon Emission Computer Tomography (SPECT for the screening of silent myocardial ischemia in type 2 diabetic patients. Material and methods: Electrocardiogram, stress test and gated-SPECT were performed on 102 type 2 diabetic patients aged 60 ± 8 years without cardiovascular symptoms. AH subjects were also subjected to a coronary angiography whose results were used as gold standard. Results: Gated-SPECT showed myocardial ischemia on 26.5% of studied patients. The sensibility, specifity accuracy, positive predictive value and negative predictive value were 92.3%, 96%, 95%, 88.8%, 97.3%, respectively. In four and six patients ischemia was detected on resting electrocardiogram and stress test, respectively. Eighty percent of patients with doubtful resting electrocardiogram results and 70% with a doubtful stress test had a silent myocardial ischemia detected by gated-SPECT There was a good agreement between the results of gated-SPECT and coronary angiography (k =0.873. Conclusions: Gated-SPECT was an useful tool for the screening of silent myocardial ischemia.

Yamilé Peña Q

2009-08-01

304

Single photon emission computed tomography (SPECT) in nuclear cardiology  

International Nuclear Information System (INIS)

This article reviews single photon emission computed tomography (SPECT) in nuclear cardiology. The described methods are multidetector scanning system, pinhole tomography and rotating gamma camera system. Myocardial SPECT with fatty acids is discussed. (Auth.)

305

Classification of /sup 201/TL and sup(99m)Tc-pertechnetate leg scan patterns and evaluation of their clinical significance  

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Classification of the /sup 201/Tl and sup(99m)Tc-pertechnetate (sup(99m)TcOsub(4-)) leg scan patterns and their clinical significance were evaluated in the patients with ischemic diseases of the lower extremities (IDL) Five patterns were distinguished in both /sup 201/Tl and sup(99m)TcOsub(4-) leg scans; A: decreased activity throughout the affected leg, B: localized decreased activity in the affected leg, C: localized decreased activity associated with increased activity in the affected leg, D: generalized of localized increased activity in the affected leg and E: no laterality of the activity. /sup 201/Tl and sup(99m)TcOsub(4-) leg scan patterns were agreed in 55% of the patients. /sup 201/Tl leg scan had tendency to correlate the level of the vascular lesion in pattern B and C,However, diagnosis of the level of the lesion was difficult from the leg scan. Pattern D of the /sup 201/Tl leg scan was associated with increased blood flow in the affected leg on radionuclide angiography in 42% of the patients. After surgery, sup(99m)TcOsub(4-) leg scan tended to show pattern D, especially in the patients with lumbar sympathectomy. Patterns A, B and C were thought to suggest the ischemia. Patterns C and D were thought to express reactive hyperemia induced by the ischemic lesion. In the 60 preoperative IDL, sensitivity of /sup 201/Tl leg scan alone was 76% and that of combined use of /sup 201/Tl and sup(99m)TcOsub(4-) leg scans was 85%. Addition of radionuclide angiography increased sensitivity of IDL upto 98% and accuracy was 98%. Combined use of /sup 201/Tl and sup(99m)TcOsub(4-) leg scans and radionuclide angiography was useful for detection of IDL, and was also useful for evaluation of the results of the surgical intervention.

Bunko, H.; Ichiyanagi, K.; Tonami, N.; Hisada, K.; Yoshida, C. (Kanazawa Univ. (Japan). School of Medicine)

1982-06-01

306

Myocardial ischemia with negative stress electrocardiography  

International Nuclear Information System (INIS)

Patients with negative stress electrocardiography (ECG) (no ST segment depression) were re-evaluated by means of stress RI studies including 201Tl single photon emission computed tomography (SPECT) and 99mTc-RBCs radionuclide ventriculography (RNV). Four hundred seven patients, including 303 with old myocardial infarction (OMI; SPECT: 188, RNV: 115) and 104 with effort angina (EA; SPECT: 58, RNV: 46), all of whom underwent left ventriculography and coronary arteriography, were re-evaluated by symptom-limited graded bicycle ergometer exercise RI testing. The results were as follows: 1. Among those with negative stress ECG (53 % of OMI and 31 % of EA), 54 % and 73 % of OMI and EA, respectively, had positive SPECT. 2. Among those with negative stress ECG (56 % of OMI and 39 % of EA), 70 % and 39 % of OMI and EA, respectively, had positive ?EF (poor increase in ejection fraction: ?EF < 5 %) and, 41 % and 28 % of OMI and EA had deteriorated regional wall motion. 3. Those with OMI and negative ECG showed no correlations with the numbers of diseased vessels, infarcted sites, or ischemic areas. In conclusion, RI testing appears to be a significantly more sensitive means of detecting stress-induced ischemia, compared to stress ECG. (author)

307

Determination of human absorbed dose of 201Tl(III)-DTPA-HIgG based on biodistribution data in rats  

International Nuclear Information System (INIS)

To estimate the absorbed dose in normal organs and inflamed tissue following i.v. administration of [201Tl](III)-DTPA-HIgG by using biodistribution data in inflammation-bearing rats was attempted. The percentages of injected dose per gram of each organ were calculated. The medical internal radiation dose formulation was applied to calculate the absorbed dose for various organs. The inflamed tissue to blood activity concentration ratios were about 19 and 23.3 at 24 and 28 h post-injection, respectively. A 185-MBq injection of 201Tl-DTPA-HIgG into the human body, might result in an estimated absorbed dose of 14.4 mGy for the total body and the highest absorbed dose was in the kidney with 1195 (mGy) and second to the Spleen were the liver, the lungs and the adrenals, which received 250.5 (mGy), 58.64 (mGy) and 56.44 (mGy), respectively. Biodistribution of [201Tl](III)-DTPA-HIgG demonstrated significant inflamed tissue uptake and low muscle and blood uptake, allowing for imaging of inflamed tissues. (authors)

308

Ischemic preconditioning effect of prodromal angina is attenuated in acute myocardial infarction patients with hypertensive left ventricular hypertrophy  

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Several animal experiments on acute myocardial infarction (AMI) have shown that the cardioprotective effects of ischemic preconditioning are more significant in hypertensive subjects. However, because there are no clinical data on the impact of hypertension on ischemic preconditioning in patients with AMI, whether clinical ischemic preconditioning of prodromal angina was beneficial in AMI patients with hypertension was investigated in the present study. 125 patients with a first anterior AMI who had undergone successful reperfusion therapy were divided into 2 groups, with or without hypertension, and into 2 further subgroups based on the presence or absence of prodromal angina. Dual-isotope (thallium-201(TL)/Tc-99m pyrophosphate) single-photon emission computed tomography (SPECT) was performed within 1 week of reperfusion therapy. Left ventricular (LV) function and LV mass index (LVMI) were measured by left ventriculography and echocardiography, respectively. In patients without hypertension, prodromal angina resulted in significantly less myocardial damage on TL-SPECT, better LV ejection fraction and a greater myocardial blush grade compared to patients without prodromal angina. However, these cardioprotective effects of prodromal angina were significantly diminished in hypertensive patients. Importantly, the myocardial salvage effects of prodromal angina showed a significant negative correlation with LVMI, which was significantly greater in hypertensive patients. Thantly greater in hypertensive patients. The cardioprotective effects of prodromal angina were attenuated in patients with hypertension. Hypertensive LV hypertrophy may crucially limit the effects of ischemic preconditioning in AMI. (author)

309

Development of [{sup 201}Tl](III)-DTPA-human polyclonal antibody complex for inflammation detection  

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Thallium-201 (T{sub 1/2}=3.04 d) in Tl{sup +} form was converted to Tl{sup 3+} cation in presence of O{sub 3} in 6 M HCl controlled by RTLC/gel electrophoresis methods and used in the labeling of human polyclonal antibody (HIgG) after conjugation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of 1 mL of a HIgG pharmaceutical solution (5 mg/ml, in phosphate buffer, pH=7) to a glass tube pre-coated with DTPA-dianhydride (0.01 mg) at 25 C with continuous mild stirring for 30 min. The final isotonic [{sup 201}Tl](III)-DTPA-HIgG complex was checked by radio-TLC using several solvent systems to ensure the formation of only one species followed by filtration through a 0.22 {mu} filter (specific activity= 33.7 TBq/mM, radiochemical purity >95%). Preliminary bio-distribution studies in normal and inflammation-bearing rats were performed. The target/skin and target/blood ratios were 4 and 6 after 28 h respectively, showing the selectivity of the radiopharmaceutical for the inflammatory lesions. (orig.)

Jalilian, A.R.; Kamali-Dehghan, M.; Kamrani, Y.Y. [Nuclear Research Center for Agriculture and Medicine, Karaj (Iran). Cyclotron and Nuclear Medicine Dept.; Khorrami, A.; Tavakoli, M.B. [Medical Sciences Univ. of Isfahan (Iran). Medical Physics and Engineering Dept.

2007-07-01

310

Development of [201Tl](III)-DTPA-human polyclonal antibody complex for inflammation detection  

International Nuclear Information System (INIS)

Thallium-201 (T1/2=3.04 d) in Tl+ form was converted to Tl3+ cation in presence of O3 in 6 M HCl controlled by RTLC/gel electrophoresis methods and used in the labeling of human polyclonal antibody (HIgG) after conjugation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of 1 mL of a HIgG pharmaceutical solution (5 mg/ml, in phosphate buffer, pH=7) to a glass tube pre-coated with DTPA-dianhydride (0.01 mg) at 25 C with continuous mild stirring for 30 min. The final isotonic [201Tl](III)-DTPA-HIgG complex was checked by radio-TLC using several solvent systems to ensure the formation of only one species followed by filtration through a 0.22 ? filter (specific activity= 33.7 TBq/mM, radiochemical purity >95%). Preliminary bio-distribution studies in normal and inflammation-bearing rats were performed. The target/skin and target/blood ratios were 4 and 6 after 28 h respectively, showing the selectivity of the radiopharmaceutical for the inflammatory lesions. (orig.)

311

A procedure for the production of injection substance containing 201Tl thallium chloride  

International Nuclear Information System (INIS)

Injection substance containing 201TlCl can be prepared by the following procedure. To a solution of irradiated thallium target in dilute H2SO4 is added a solution of KBrO3 in an amount at least sufficient for transforming all the thallium to the trivalent state. A solution of NaBr or KBr is then added and the target amount of Tl is separated from 201Pb by repeated extraction into diisopropyl ether. In 24 to 40 hr, KBrO3 is again added in an amount at least such that thallium is transformed to the trivalent state, and the latter is separated from lead by a single extraction into diisopropyl ether. The organic phase is washed with a solution of NaBr or KBr in dilute H2SO4 and reextracted into injection-grade water containing dissolved SO2. The reextract is evaporated, dissolved in buffer-containing isotonic solution and autoclaved. The chemical yield is 97 to 98%, the first step of the procedure takes 30 to 35 min, and the technological yield of the process is 90%. The injection is high-quality. (P.A.)

312

Myocardial perfusion abnormality and chest pain in patients with hypertrophic cardiomyopathy  

International Nuclear Information System (INIS)

To investigate the role of myocardial ischemia in the development of chest pain in patients with hypertrophic cardiomyopathy (HCM), exercise stress (Ex) redistribution myocardial single photon emission CT's (SPECT's) with thallium-201 (Tl) were obtained in 27 patients with HCM. In all patients, coronary arteries were normal arteriographically. Patients were classified into NYHA Class I, II and III according to the frequency and severity of the chest pain during daily life. In these 3 groups, age, sex and intraventricular septal thickness measured by echocardiography were not different. Types of myocardial perfusion obtained by myocardial SPECT's were divided into 5: (1) normal perfusion, (2) no perfusion defect with abnormal myocardial Tl washout rate (WOR) during 3 hours (<30%) [Def(-)/WORabn], (3) reversible perfusion defect (RD), (4) fixed defect with abnormal WOR (FD/WORabn), and (5) fixed defect with normal WOR (FD/WORnl). In 14 patients of Class I, 9 patients (64%) showed normal perfusion but the rest showed perfusion abnormality (def(-)/WORabn in 3 and RD in 2). In Class II and III, all patients showed perfusion abnormalities of RD, FD/WORabn or FD/WORnl. As the functional class progressed from Class II to III, the ratio of fixed defect (both WORnl and WORabn) to RD increased, but it was not statistically significant. In 2 patients in whom Ex SPECT's were repeated because of the progression of the chest pain, the severity of the perfusion abnormality also progrty of the perfusion abnormality also progressed. Perfusion abnormalities were observed most frequently in anterior (35%), then inferior/posterior (20%) and septal wall (18%). The frequency of Ex induced ECG abnormalities (ST-depression or T wave changes) increased as the NYHA Class progressed (Class III vs I p<0.05). These findings suggested the following: chest pain in patients with HCM relates to the myocardial ischemia which may originate in the myocardial small arteries, and when the lesions progress myocardial necrosis may ensue. (author)

313

Prognostic value of technetium-99m-labeled single-photon emission computerized tomography in the follow-up of patients after their first myocardial revascularization surgery Valor prognóstico da tomografia miocárdica de perfusão com radiofármacos ligados ao tecnécio-99m no acompanhamento de pacientes submetidos à primeira cirurgia de revascularização miocárdica  

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OBJECTIVE: To assess the prognostic value of Technetium-99m-labeled single-photon emission computerized tomography (SPECT) in the follow-up of patients who had undergone their first myocardial revascularization. METHODS: We carried out a retrospective study of 280 revascularized patients undergoing myocardial scintigraphy under stress (exercise or pharmacological stress with dipyridamole) and at rest according to a 2-day protocol. A set of clinical, stress electrocardiographic and scintigraph...

Márcia Maria Sales dos Santos; Eduardo Cwajg; Mauricio da Rocha Pantoja

2003-01-01

314

Single photon emission computerized tomography  

International Nuclear Information System (INIS)

In this thesis two single-photon emission tomographic techniques are presented: (a) longitudinal tomography with a rotating slanting-hole collimator, and (b) transversal tomography with a rotating gamma camera. These methods overcome the disadvantages of conventional scintigraphy. Both detection systems and the image construction methods are explained and comparisons with conventional scintigraphy are drawn. One chapter is dedicated to the determination of system parameters like spatial resolution, contrast, detector uniformity, and size of the object, by phantom studies. In separate chapters the results are presented of detection of tumors and metastases in the liver and the liver hilus; skeletal diseases; various pathological aberrations of the brain; and myocardial perfusion. The possible use of these two ect's for other organs and body areas is discussed in the last chapter. (Auth.)

315

Evaluation of myocardial perfusion by scanner and by gamma camera with computer ES 1020  

International Nuclear Information System (INIS)

The regional myocardial perfusion was studied in 660 patients with myocardial infraction, stenocardia and myocardio-sclerosis. 408 patients were examined by scanner with 131Cs chloride, 95 patients with 201Tl chloride and 78 ones by gamma radiation camera and scanner with 201Tl chloride. Scanning with both radiocolloids reveals directly perfusion disturbances of a large and moderate size. The gamma radiation camera with computer reveals perfusion disturbances of a small and micro size which cannot be detected by the scanner. This technique is more precise and gives a more detailed information concerning the localization, degree and size of the perfusion disturbances. It is suggested that examination of myocardial perfusion by gamma radiation camera with computer using radiocolloid 201Tl chloride gives the best results and should be preferred

316

Adenosine technetium-99m sestamibi single-photon emission tomography for the assessment of jeopardized myocardium early after acute myocardial infarction. Paradoxical scintigraphic underestimation of jeopardized myocardium in patients with a severe infarct-related stenosis  

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In 51 patients with a recent (<1 month) myocardial infarction, adenosine {sup 99m}Tc-sestamibi single-photon emission tomography (SPET) and dobutamine stress echocardiography (DSE) were performed and correlated with the presence of significant coronary artery stenosis on quantitative coronary angiography. Regional perfusion activity was analysed semi-quantitatively (score 0-4) on a 13-segment left ventricular model. DSE was used for the estimation of the infarct size (low-dose DSE) and for concomitant evaluation of ischaemia (high-dose DSE). A reversible perfusion defect within the infarct region was observed in 20 of the 37 patients with a significant infarct-related lesion (sensitivity of 54%) and only in one patient without a significant infarct-related lesion (specificity of 93%). Further analysis revealed that the scintigraphic assessment of jeopardized myocardium was fairly good in patients with a moderate (DS 51%-64%) infarct-related stenosis but was inadequate in patients with a severe (DS{>=}65%) infarct-related stenosis, while the echocardiographic detection of ischaemia was not influenced by stenosis severity (sensitivity of 73% in both subgroups). This scintigraphic underestimation of jeopardized myocardium was mainly related to a severely impaired myocardial perfusion under baseline conditions, as was evidenced by a significantly more severe rest perfusion score in the infarct region in patients with a severe stenosis as compared to those with a moderate stenosis, while infarct size on echocardiography was similar for both subgroups. It may be concluded that early after an acute myocardial infarction, adenosine {sup 99m}Tc-sestamibi SPET may underestimate reperfused but still jeopardized myocardium, particularly in patients with a severe infarct-related stenosis. In these patients the evaluation of the ischaemic burden on rest-stress scintigraphy is hampered by the presence of a severely impaired myocardial perfusion in resting conditions. (orig./MG). With 2 figs., 1 tab.

Claeys, M.J.; Rademakers, F.E.; Vrints, C.J.; Snoeck, J.P. [Department of Cardiology, Antwerp University Hospital, Edegem (Belgium); Blockx, P.P. [Department of Nuclear Medicine, Antwerp University Hospital, Edegem (Belgium)

1997-09-01

317

Analysis of heavy metals in [201Tl]TlCl injection using polarography  

International Nuclear Information System (INIS)

Thallous-201 chloride produced at Korea Cancer Center Hospital(KCCH) is used in detecting cardiovascular disease and cancer. Thallium impurity can cause emesis, catharsis and nausea, so the presence of thallium and other metal impurities should be determined. According to USP and KP, their amounts must be less than 2 ppm in thallium and 5 ppm in total. In this study, the detection method of trace amounts of metal impurities in [201Tl]TlC1 injection with polarography was optimized without environmental contamination. For the detection of metal impurities, Osteryoung Square Wave Stripping Voltammetry method was used in Bio-Analytical System (BAS) 50W polarograph. The voltammetry was composed of Dropping Mercury Electrode (DME) as a working electrode, Ag/AgCl as a reference electrode and Pt wire as a counter electrode. Square wave stripping method, which makes use of formation and deformation of amalgam, was adopted to determine the metal impurities, and pH 7 phosphate buffer was used as supporting electrolyte. T1, Cu and Pb in thallous-201 chloride solution were detected by scanning from 300mV to -800mV. Calibration curves were made by using TINO3, CuSO4 and Pb(NO3)2 as standard solutions. T1 was confirmed at -450mV peak potential and Cu at -50mV. Less than 2 ppm of T1 and Cu was detected and Pb was not detected in KCCH-produced thallous-201 chloride injection. Detection limit of thallium and copper is approximatelyit of thallium and copper is approximately 50 ppb with this method. As a result of this experiment, thallium and other metal impurities in thallous-201 chloride injection, produced at Korea Cancer Center Hospital, are in the regulation of USP and KP. Polarograph could be applied for the determination of metal impurities in the quality control of radiopharmaceuticals conveniently without environmental contamination.=20

318

Analysis of heavy metals in [{sup 201}Tl]TlCl injection using polarography  

Energy Technology Data Exchange (ETDEWEB)

Thallous-201 chloride produced at Korea Cancer Center Hospital(KCCH) is used in detecting cardiovascular disease and cancer. Thallium impurity can cause emesis, catharsis and nausea, so the presence of thallium and other metal impurities should be determined. According to USP and KP, their amounts must be less than 2 ppm in thallium and 5 ppm in total. In this study, the detection method of trace amounts of metal impurities in [{sup 201}Tl]TlC1 injection with polarography was optimized without environmental contamination. For the detection of metal impurities, Osteryoung Square Wave Stripping Voltammetry method was used in Bio-Analytical System (BAS) 50W polarograph. The voltammetry was composed of Dropping Mercury Electrode (DME) as a working electrode, Ag/AgCl as a reference electrode and Pt wire as a counter electrode. Square wave stripping method, which makes use of formation and deformation of amalgam, was adopted to determine the metal impurities, and pH 7 phosphate buffer was used as supporting electrolyte. T1, Cu and Pb in thallous-201 chloride solution were detected by scanning from 300mV to -800mV. Calibration curves were made by using TINO{sub 3}, CuSO{sub 4} and Pb(NO{sub 3}){sub 2} as standard solutions. T1 was confirmed at -450mV peak potential and Cu at -50mV. Less than 2 ppm of T1 and Cu was detected and Pb was not detected in KCCH-produced thallous-201 chloride injection. Detection limit of thallium and copper is approximately 50 ppb with this method. As a result of this experiment, thallium and other metal impurities in thallous-201 chloride injection, produced at Korea Cancer Center Hospital, are in the regulation of USP and KP. Polarograph could be applied for the determination of metal impurities in the quality control of radiopharmaceuticals conveniently without environmental contamination.

Chun, Kwon Soo; Suh, Yong Sup; Yang, Seung Dae; Ahn, Soon Hyuk; Kim, Sang Wook; Choi, Kang Hyuk; Lee, Dong Hoon; Lim, Sang Moo [Korea Cancer Center Hospital, Seoul (Korea, Republic of); Yu, Kook Hyun [Dongguk Univ., Seoul (Korea, Republic of)

2000-08-01

319

Quantitative assessment of 201Tl-SPECT in tumors of bone and soft tissue  

International Nuclear Information System (INIS)

201Tl-SPECT was performed to diagnose the malignancy of bone and soft tissue tumors by visual and quantitative assessment in 48 patients. SPECT images were obtained in the early phase and the delayed phase. By visual assessment a tumor was considered malignant if high accumulation was found in the tumor in early phase and the accumulation was confirmed in the delayed phase. Tumors which did not meet these criteria were considered benign. For quantitative assessment, the ROI (region of interest) accumulation ratios of the tumor to the contralateral normal tissue in the early phase (ER) and in the delayed phase (DR), the ROI accumulation ratio of the delayed phase to the early phase of the tumor (Td/Te), and the ROI accumulation ratio of the delayed phase to the early phase of the contralateral normal tissue (Nd/Ne) were obtained. Sixteen patients with malignant tumors each had a high accumulation each but 12 of 31 benign lesions had no high accumulation on visual assessment. Furthermore, the accuracy was 85.4%, sensitivity 94.1%, and specificity 80.6%. Quantitative assessment was performed for 36 cases of high accumulation. The ER of malignant and benign lesions was 5.51±3.73 and 2.75±2.17, respectively, and the ER of malignant lesions was significantly higher than that of benign lesions. The DR did not demonstrate a significant difference. If the tumor having an ER greater than 3.9 was assumed to be malignant, the accuracy for differentiating malignant leccuracy for differentiating malignant lesions from benign lesions was 85.4%. The Td/Te of benign lesions was higher than that of malignant lesions. The Nd/Ne of normal tissue which contained muscles in both lesions were higher than 1.4. (K.H.)

320

Myocardial perfusion imaging with technetium-99m sestamibi SPECT in the evaluation of coronary artery disease  

International Nuclear Information System (INIS)

Technetium-99m (Tc-99m) sestamibi is a new myocardial perfusion imaging agent that offers significant advantages over thallium-201 (Tl-201) for myocardial perfusion imaging. The results of the current clinical trials using acquisition and processing parameters similar to those for Tl-201 and a separate (2-day) injection protocol suggest that Tc-99m sestamibi and Tl-201 single photon emission computed tomography (SPECT) provide similar information with respect to detection of myocardial perfusion defects, assessment of the pattern of defect reversibility, overall detection of coronary artery disease (CAD) and detection of disease in individual coronary arteries. Tc-99m sestamibi SPECT appears to be superior to Tc-99m sestamibi planar imaging because the former provides a higher defect contrast and is more accurate for detection of disease in individual coronary arteries. Research is currently under way addressing optimization of acquisition and processing of Tc-99m sestamibi studies and development of quantitative algorithms for detection and localization of CAD and sizing of transmural and nontransmural myocardial perfusion defects. It is expected that with the implementation of the final results of these new developments, further significant improvement in image quality will be attained, which in turn will further increase the confidence in image interpretation. Development of algorithms for analysis of end-diastolic myocardial images may allow better evaluation of sal images may allow better evaluation of small and nontransmural myocardial defects. Furthermore, gated studies may provide valuable information with respect to regional myocardial wall motion and wall thickening. With the implementation of algorithms for attenuation and scatter correction, the overall specificity of Tc-99m sestamibi SPECT should improve significantly. 32 references

 
 
 
 
321

Processing by factor analysis of dynamic dual isotope studies using 99Tcm and 201Tl within a middle energy band. Evaluation in thyroid nodule malignancy  

International Nuclear Information System (INIS)

Simultaneous investigations with two isotopes are currently restricted because of a spectral overlap. The factor analysis of spectral and dynamic structures (FASDS) method is shown to achieve accurate spectral separation. In addition, it estimates underlying dynamic mechanisms. Twenty-six patients were injected simultaneously with 99Tcm-pertechnetate and 201Tl-chloride to assess the malignancy of solitary thyroid nodules. List-mode acquisition of spectral, temporal and spatial coordinates of events allows the reconstruction of an image sequence indexed by time and energy. FASDS proceeds in two steps. First it yields both dynamic and spatial information related to each isotope (99Tcm and 201Tl) and partially removes the scatter component. Then it estimates the underlying kinetics and associated spatial distributions of each isotope. Using the 201Tl component, an index was derived from the uptake ratio between nodules and normal thyroid tissue. Concerning the detection of malignant nodules the method indicated no false negative in our limited group of 26 patients. One false positive result was found which could not be classified by the investigation of the 201Tl dynamic components contained in the reconstructed 201Tl factor sequence. (Author)

322

Differences between accumulation of 99mTc-MIBI and 201Tl-Thallous Chloride in tumour cells: Role of P-glycoprotein  

International Nuclear Information System (INIS)

Both 99mTc-MIBI and 201Tl have been used for tumour imaging. It has recently been reported that 99mTc-MIBI is a substrate for P-glycoprotein (Pgp), a membrane pump which mediates multidrug resistance. It has been evaluated the role of Pgp in the cellular accumulation of 201TI by using sensitive and resistant strains of Chinese hamster ovary (CHO) fibroblasts (AuxB1 and CHRC5, respectively) grown in suspension culture. 201Tl accumulation was the same in sensitive and resistant cells, whereas 99mTc-MIBI accumulation was much lower in resistant cells than in sensitive ones. Down-modulation of Pgp with 100 ?M verapamil did not alter cellular accumulation of 201Tl while it significantly increased 99mTc-MIBI accumulation in both types of cell. Similarly, 10 ?M verapamil did not affect the rate of washout of 201Tl from preloaded cells, while 99mTc-MIBI washout was greatly reduced in the presence of verapamil. These results suggest that 201Tl will accumulate in both sensitive and resistant tumour cells, whereas 99mTc-MIBI will be extruded from resistant cells and therefore may be less useful for tumour detection when the tumour cells express high Pgp levels

323

Abnormal regional glucose and fatty acid metabolism in patients with ischemic heart disease. Assessment by 18F-FDG-PET, 123I-BMIPP-SPECT, and 201Tl-SPECT  

International Nuclear Information System (INIS)

To evaluate myocardial metabolic dysfunction relative to changes in myocardial perfusion and function, 20 patients (73 myocardial segments) with ischemic heart disease underwent 18F-FDG-PET, 123I-BMIPP-SPECT, and 201Tl-SPECT. There were 46 segments with normal FDG accumulation, 32 with normal BMIPP accumulation, 19 with mildly reduced FDG accumulation, 16 with mildly reduced BMIPP accumulation, 8 with severely reduced FDG accumulation, and 25 with severely reduced BMIPP accumulation. Therefore, the percentage of segments with reduced fatty acid metabolism is greater than the percentage with reduced glucose metabolism. Reduced FDG accumulation and reduced BMIPP accumulation were present in 17% and 37% (P=0.01) of segments with normal wall motion respectively, 35% and 73% (P=0.045) of segments with mildly reduced wall motion, and 93% and 100% (P=NS) of segments with severely reduced wall motion. Similarly, perfusion defects were identified with Tl, in 30%, 54%, and 93% of segments with normal, mildly reduced, and severely reduced wall motion, respectively. In the setting of ischemic heart disease, there are greater abnormalities in fatty acid metabolism than in glucose metabolism. Myocardial metabolism switches from fatty acid to glucose utilization with mild ischemia, although glucose metabolism is impaired as ischemia becomes more severe. (author)

324

Duke treadmill score (DTS) and gated single photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) in chest pain patient initial experience  

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Background: Risk stratification of the patient with suspected or known coronary artery disease(CAD)by means of non-invasive testing are highly relevant in clinical cardiology for the selection of patient who require further diagnostic or therapeutic investigation. Aim: To predict severity of myocardial ischaemia by exercise tolerance test (ETT) determined duke treadmill score (DTS) and myocardial perfusion study. Material and methods: A total of 108 (92-men) patients presenting with Canadian cardiovascular society (CCS) class Mil severity of chest pain, mean age 49.88+8.44 yrs, were studied during October 2002-march 2003. All patient underwent ETT and SPECT-MPI scan using Tc-99m-tetrofosmin in one-day stress and rest protocol. Coronary angiogram (CAG) was done within six months of the perfusion study. After performing ETT, patients were categorized by DTS, myocardial perfusion studies were also stratified according to severity of perfusion defect. The angiographic findings (significant>50% stenosis) and perfusion defects in MPI were compared with the severity of DTS. Result: In high DTS group 91.66% patients had perfusion defect, whereas in intermediate and low risk group it was 60% and 40.90% respectively. In high DTS group 91.66% of patient had angiographically proven CAD, 58.33% of them had triple vessel disease (TVD) while in intermediate and low risk group angiographically proven CAD were 65% and 22.27% of whom TVD only in 15% and 0% respectively. Conclusion: Then 15% and 0% respectively. Conclusion: The results of ETT using DTS score satisfactorily correlate with SPECT-MPI scanning in high DTS subsets of patients .So it is suggested that patient of high risk DTS could undergo CAG for further evaluation without radio-nuclide perfusion study. Intermediate and low risk needs myocardial perfusion imaging study to guide for further evaluation. (authors)

325

Adenosine technetium-99m sestamibi single-photon emission tomography for the assessment of jeopardized myocardium early after acute myocardial infarction. Paradoxical scintigraphic underestimation of jeopardized myocardium in patients with a severe infarct-related stenosis  

International Nuclear Information System (INIS)

In 51 patients with a recent (99mTc-sestamibi single-photon emission tomography (SPET) and dobutamine stress echocardiography (DSE) were performed and correlated with the presence of significant coronary artery stenosis on quantitative coronary angiography. Regional perfusion activity was analysed semi-quantitatively (score 0-4) on a 13-segment left ventricular model. DSE was used for the estimation of the infarct size (low-dose DSE) and for concomitant evaluation of ischaemia (high-dose DSE). A reversible perfusion defect within the infarct region was observed in 20 of the 37 patients with a significant infarct-related lesion (sensitivity of 54%) and only in one patient without a significant infarct-related lesion (specificity of 93%). Further analysis revealed that the scintigraphic assessment of jeopardized myocardium was fairly good in patients with a moderate (DS 51%-64%) infarct-related stenosis but was inadequate in patients with a severe (DS?65%) infarct-related stenosis, while the echocardiographic detection of ischaemia was not influenced by stenosis severity (sensitivity of 73% in both subgroups). This scintigraphic underestimation of jeopardized myocardium was mainly related to a severely impaired myocardial perfusion under baseline conditions, as was evidenced by a significantly more severe rest perfusion score in the infarct region in patients with a severe stenosis as compared to those with a moderenosis as compared to those with a moderate stenosis, while infarct size on echocardiography was similar for both subgroups. It may be concluded that early after an acute myocardial infarction, adenosine 99mTc-sestamibi SPET may underestimate reperfused but still jeopardized myocardium, particularly in patients with a severe infarct-related stenosis. In these patients the evaluation of the ischaemic burden on rest-stress scintigraphy is hampered by the presence of a severely impaired myocardial perfusion in resting conditions. (orig./MG). With 2 figs., 1 tab

326

Prevalence and prognostic value of perfusion defects detected by stress technetium-99m sestamibi myocardial perfusion single-photon emission computed tomography in asymptomatic patients with diabetes mellitus and no known coronary artery disease.  

Science.gov (United States)

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in diabetics. Early diagnosis of CAD and identification of high-risk subgroups, followed by appropriate therapy, may therefore enhance survival. This study sought to determine the value of stress myocardial perfusion single-photon emission computed tomography (SPECT) with technetium-99m sestamibi to detect perfusion defects and predict cardiac events in asymptomatic diabetics. One hundred eighty asymptomatic diabetics without known CAD who underwent 2-day stress technetium-99m sestamibi SPECT were followed up for 36 +/- 18 months. End points were defined as hard (myocardial infarction or cardiac death) or total events (myocardial infarction, cardiac death, or late revascularization). Logistic regression analysis evaluated clinical variables, type of stress, exercise treadmill test (ETT), and SPECT as predictors of end points. Perfusion defects were found in 26% of patients (15% reversible, 6% mixed, and 5% fixed). Clinical or ETT variables were not associated with perfusion defect type or with hard events. However, male gender predicted total events (chi-square 3.3; p = 0.01). An abnormal SPECT significantly increased the risk of hard events (chi-square 5.4; p = 0.001) and total events (chi-square 7.4; p = 0.0001). Extensive defects determined the highest risk of total events (chi-square 18.8; p = 0.0001). Event rates increased according to SPECT: 2% of hard events per year and 5% of total events per year in patients with normal SPECT versus 9% per year and 38% per year, respectively, in those with abnormal SPECT. Importantly, a normal SPECT identified a relatively low-risk subgroup of patients. Thus, stress technetium-99m sestamibi SPECT was useful in evaluating asymptomatic diabetics for the presence of CAD, and effectively risk-stratified this population. PMID:12372568

De Lorenzo, Andrea; Lima, Ronaldo S L; Siqueira-Filho, Aristarco G; Pantoja, Mauricio R

2002-10-15

327

Impact of intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction on left ventricular perfusion and function: a 6-month follow-up gated 99mTc-MIBI single-photon emission computed tomography study  

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We investigated the impact of intracoronary injection of autologous mononuclear bone marrow cells (BMC) in patients with acute ST elevation myocardial infarction (STEMI) on left ventricular volumes, global and regional systolic function and myocardial perfusion. The study included 39 patients with first anterior STEMI treated successfully with primary percutaneous coronary intervention. They were randomly assigned to the treatment group or the control group in a 2:1 ratio. The patients underwent baseline gated single-photon emission computed tomography (G-SPECT) 3-10 days after STEMI with quantitative and qualitative analysis of left ventricular perfusion and systolic function. On the following day, patients from the BMC treatment group were subjected to bone marrow aspiration, mononuclear BMC isolation and intracoronary injection. No placebo procedure was performed in the control group. G-SPECT was repeated 6 months after STEMI. Baseline and follow-up G-SPECT studies were available for 36 patients. At 6 months in the BMC group we observed a significantly enhanced improvement in the mean extent of the perfusion defect, the left ventricular perfusion score index, the infarct area perfusion score and the infarct area wall motion score index compared to the control group (p=0.01-0.04). However, the changes in left ventricular volume, ejection fraction and the left ventricular wall motion score index as well as the relative changes in the infarct area wall motion score ins in the infarct area wall motion score index did not differ significantly between the groups. Intracoronary injection of autologous mononuclear BMC in patients with STEMI improves myocardial perfusion at 6 months. The benefit in infarct area systolic function is less pronounced and there is no apparent improvement of global left ventricular systolic function. (orig.)

328

Impact of intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction on left ventricular perfusion and function: a 6-month follow-up gated {sup 99m}Tc-MIBI single-photon emission computed tomography study  

Energy Technology Data Exchange (ETDEWEB)

We investigated the impact of intracoronary injection of autologous mononuclear bone marrow cells (BMC) in patients with acute ST elevation myocardial infarction (STEMI) on left ventricular volumes, global and regional systolic function and myocardial perfusion. The study included 39 patients with first anterior STEMI treated successfully with primary percutaneous coronary intervention. They were randomly assigned to the treatment group or the control group in a 2:1 ratio. The patients underwent baseline gated single-photon emission computed tomography (G-SPECT) 3-10 days after STEMI with quantitative and qualitative analysis of left ventricular perfusion and systolic function. On the following day, patients from the BMC treatment group were subjected to bone marrow aspiration, mononuclear BMC isolation and intracoronary injection. No placebo procedure was performed in the control group. G-SPECT was repeated 6 months after STEMI. Baseline and follow-up G-SPECT studies were available for 36 patients. At 6 months in the BMC group we observed a significantly enhanced improvement in the mean extent of the perfusion defect, the left ventricular perfusion score index, the infarct area perfusion score and the infarct area wall motion score index compared to the control group (p=0.01-0.04). However, the changes in left ventricular volume, ejection fraction and the left ventricular wall motion score index as well as the relative changes in the infarct area wall motion score index did not differ significantly between the groups. Intracoronary injection of autologous mononuclear BMC in patients with STEMI improves myocardial perfusion at 6 months. The benefit in infarct area systolic function is less pronounced and there is no apparent improvement of global left ventricular systolic function. (orig.)

Lipiec, Piotr [Medical University of Lodz, 2nd Department of Cardiology, Lodz (Poland); Medical University of Lodz, 2nd Department of Cardiology, Bieganski Hospital, Lodz (Poland); Krzeminska-Pakula, Maria; Plewka, Michal; Kasprzak, Jaroslaw D. [Medical University of Lodz, 2nd Department of Cardiology, Lodz (Poland); Kusmierek, Jacek; Plachcinska, Anna; Szuminski, Remigiusz [Medical University of Lodz, Department of Nuclear Medicine, Lodz (Poland); Robak, Tadeusz; Korycka, Anna [Medical University of Lodz, Department of Hematology, Lodz (Poland)

2009-04-15

329

Assessment of the effect of revascularization early after CABG using ECG-gated perfusion single-photon emission tomography  

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When an arterial graft is used, reversible perfusion defects on single-photon emission tomography (SPET) perfusion images are occasionally observed early after coronary artery bypass graft surgery (CABG), owing to the restricted flow capacity. The purpose of this study was to determine whether the functional information obtained with electrocardiography (ECG)-gated perfusion SPET could be helpful in evaluating the effect of revascularization early after CABG. Twenty-three patients (18 men and 5 women, mean age 65{+-}9 years) underwent stress/re-injection thallium-201 ECG-gated SPET before and 4 weeks after CABG (13 with exercise and 10 with dipyridamole). Patency of all grafts was confirmed by coronary angiography 1 month after CABG. Cardiac functional data including the left ventricular ejection fraction (LVEF) and the transient ischaemic dilatation (TID) ratio were analysed using a commercially available automated program. The conventional stress and re-injection tomograms were interpreted by means of a five-point scoring system in a nine-segment model. Stress-induced reversible {sup 201}Tl perfusion defects were present in 64% of the myocardial segments bypassed by patent arterial grafts, in contrast to 42% of the myocardial segments bypassed by patent venous grafts ({chi}{sup 2}=7.8, P=0.005). Of the 23 patients, 12 showed improvement in summed ischaemic scores (group 1), while 11 had no change or deterioration (group 2), although all grafts were patent on postoperative catheterization. The TID ratio improved in both group 1 and group 2 before and after CABG (1.14{+-}0.13 vs 0.99{+-}0.07, P=0.001 and 1.09{+-}0.07 vs 0.94{+-}0.05, P=0.002, respectively). However, LVEF did not significantly improve in group 1 or group 2 after CABG (42.5%{+-}9.9% vs 47.5%{+-}11.8%, and 52.1%{+-}7.5% vs 53.1%{+-}5.9%, respectively). Perfusion imaging or LVEF assessment is of limited value early after CABG. The TID ratio obtained with ECG-gated perfusion SPET may be a useful marker to evaluate the effect of revascularization early after surgery. (orig.)

Kubo, Shigeto; Tadamura, Eiji; Kudoh, Takashi; Inubushi, Masayuki; Konishi, Junji [Dept. of Nuclear Medicine and Diagnostic Imaging, Kyoto University Graduate (Japan); Ikeda, Tadashi; Koshiji, Takaaki; Nishimura, Kazunobu; Komeda, Masashi [Dept. of Cardiovascular Surgery, Kyoto University (Japan); Tamaki, Nagara [Dept. of Nuclear Medicine, Hokkaido University, Sapporo (Japan)

2001-02-01

330

The quantitative diagnosis of thallium-201 myocardial perfusion images and vectorcardiograms in myocardial infarction and hypertrophic cardiomyopathy  

International Nuclear Information System (INIS)

Correlation studies were carried out between thallium-201 myocardial perfusion images and vectorcardiograms in 77 patients with myocardial infarction (48 anterior and 29 inferior infarctions) and 30 patients with hypertrophic cardiomyopathy. A quantitative method was developed; myocardial 201Tl uptake index (a relative myocardial activity to background, MUI) and myocardial 201Tl uptake ratio (a ratio of regional myocardial counts to maximal myocardial counts, MUR) were utilized to differentiate myocardial infarction from hypertrophic cardiomyopathy, and evaluate them. A fairly good agreement between left ventriculograms and myocardial perfusion images was obtained in myocardial infarction (diagnostic accuracy 95.1% in anterior and 75.6% in inferior infarction). In anterior infarction the linear relationship of r = -0.58 (p 201Tl images (septal, apical and anterior, apical and septal, and anterior dominant types). Azimuth angles of instantaneous 10 msec vector were directed right-anteriorly (mean 114.5 degrees) in septal hypertrophy, and left-anteriorly (mean 84.9 degreeshy, and left-anteriorly (mean 84.9 degrees) in apical and anterior hypertrophy. Elevation angle of maximal T vector in apical hypertrophy was deviated superiorly (mean 102.6 degrees). There was a good correlation (r = 0.60, p < 0.001) between the magnitude of spatial maximal QRS vector and lateral wall MUR. (author)

331

Thallium-201 stress-redistribution myocardial rotational tomography: development of criteria for visual interpretation  

International Nuclear Information System (INIS)

Despite high sensitivity and specificity for overall detection of coronary artery disease (CAD), planar stress-redistribution thallium-201 (Tl-201) scintigraphy remains suboptimal in localizing disease, because of overlap of myocardial segments. Single photon emission computerized tomography (SPECT), by providing three-dimensional representation of myocardial Tl-201, offers promise for improved localization of CAD. In 50 consecutive patients (22 normal and 28 with CAD), who underwent SPECT stress-redistribution Tl-201 imaging, we systemically developed visual interpretive criteria for perfusion abnormality on SPECT. For overall detection of disease, the best criterion for abnormality was greater than or equal to 8 sectors of moderately decreased Tl-201 uptake. With this criterion, the true positive and true negative rates for overall detection of disease were 96% and 91%, respectively. The best criterion for significant defect in the anterior or posterior coronary circulation was greater than or equal to 3 sectors of moderately decreased Tl-201 uptake. With this criterion, the true positive and true negative rates for anterior circulation disease were 71% and 100%, respectively. With respect to posterior circulation disease, the true positive and true negative rates were 100% and 50%, respectively. Regarding identification of dual circulation disease, the true positive and true negative rates were 71% and 82%, respectively

332

Experimental study of hypoxic preconditioning on 99Tcm-MIBI and 201Tl kinetics in cultured neonatal rat cardio-myocytes  

International Nuclear Information System (INIS)

Objective: To study the effect of hypoxic preconditioning (HPC) on 99Tcm-MIBI and 201Tl kinetics in cultured neonatal rat cardio-myocytes. Methods: The protection of HPC was assayed on the model of hypoxia/reoxygenation (H/R) of cultured neonatal rat cardio-myocytes and the Trypan blue exclusion method was used to assess cell viability. Normal, hypoxic preconditioning and hypoxia/reoxygenation cardio-myocytes groups were studied. By measuring the diffused and released radioactivity of myocytes in different time intervals, the effect of HPC on 99Tcm-MIBI and 201Tl uptake and clearance kinetics in the myocytes was observed in various conditions. Results: Compared with H/R, the number of viable cells after HPC [(75.31 +- 3.45)% vs (55.50 +- 3.13)%, P 99Tcm-MIBI and 201Tl to a plateau level with a half-time of 12.8 min and 6.5 min, respectively. HPC caused a significant increase in uptake of 99Tcm-MIBI [normal control, (4852 +- 491) counts·min-1·mg-1 protein to HPC group, (6103 +- 170) counts·min-1·mg-1 protein; P 201Tl uptake [normal control, (3190 +- 183) counts·min-1·mg-1 protein to HPC group, (2120 +- 202) counts·min-1·mg-1 protein; P protein; P 99Tcm-MIBI and 201Tl were both retarded. Conclusions: These results suggested that the neonatal rat cardio-myocytes after HPC offered more capacity to tolerate the H/R damage and HPC could influence the 99Tcm-MIBI and 201Tl uptake and clearance

333

Radionuclide imaging in myocardial sarcoidosis. Demonstration of myocardial uptake of /sup 99m/Tc pyrophosphate and gallium  

International Nuclear Information System (INIS)

A patient had severe congestive cardiomyopathy secondary to myocardial sarcoidosis. The clinical diagnosis was confirmed by radionuclide ventriculography, 201Tl, 67Ga, and /sup 99m/Tc pyrophosphate (TcPYP) scintigraphy. Myocardial TcPYP uptake has not been reported previously in sarcoidosis. In this patient, TcPYP was as useful as gallium scanning and thallium imaging in documenting the myocardial process

334

Effectiveness of planar image and single photon emission tomography of thallium-201 compared with gallium-67 in patients with primary lung cancer  

International Nuclear Information System (INIS)

A comparative study of planar images and single photon emission tomography (SPET) of thallium-201 chloride and gallium-67 citrate was performed in 38 patients with proven primary lung cancer to detect the primary lung tumour and to establish the presence of metastasis in the lung hilum and mediastinum. The findings of planar images and SPET were compared with the pathological findings after thoracotomy. It was shown that 201Tl studies were superior to 67Ga studies for evaluation of the primary lesion and lymph node metastases. (orig.)

335

Evaluation of left ventricular function and volume in patients with dilated cardiomyopathy : gated myocardial single-photon emission tomography (SPECT versus echocardiography.  

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Full Text Available Background: Left ventricular function, volumes and regional wall motion provide valuable diagnostic information and are of long-term prognostic importance in patients with dilated cardiomyopathy (DCM. This study was designed to compare the effectiveness of 2D-echocardiography and gated single-photon emission tomography (SPECT for evaluation of these parameters in patients with DCM. Patients and Methods: Gated SPECT and 2D-echocardiography were performed in 33 patients having DCM. Gated SPECT data, including left ventricular volumes and left ventricular ejection fraction (LVEF, were processed using an automated algorithm. Standard technique was used for 2D-echocardiography. Regional wall motion was evaluated using both modalities and was scored by two independent observers using a 16-segment model with a 5-point scoring system. Results: The overall agreement between the two imaging modalities for the assessment of regional wall motion was 56% (298/528 segments. With gated SPECT, LVEF, end-diastolic volume (EDV, and end-systolic volume (ESV were 27±9%, 217±77 mL, and 163±73 mL, respectively, and 30±8%, 195±58 mL, and 137±48 mL with echocardiography. The correlation between gated SPECT and 2D-echocardiography was good (r=0.76, P< 0.01 for the assessment of LVEF. The correlation for EDV and ESV were also good, but with wider limits of agreement (r=0.72, P< 0.01 and r=0.73, P< 0.01, respectively and significantly higher values were obtained with gated SPECT (P< 0.01. Conclusions: Gated SPECT and 2D-echocardiography correlate well for the assessment of LV function and LV volumes. Like 2D-echocardiography, gated SPECT provides reliable information about LV function and dimension with the additional advantage of perfusion data.

Berk Fatma

2005-01-01

336

Iodine-123 phenylpentadecanoic acid: detection of acute myocardial infarction and injury in dogs using an iodinated fatty acid and single-photon emission tomography  

International Nuclear Information System (INIS)

The ability of an iodinated fatty acid, iodine-123 phenylpentadecanoic acid (1-123 PPA), and single-photon emission computed tomography (SPECT) to detect myocardium injured by temporary or permanent coronary arterial occlusion was evaluated. In 5 control dogs, 11 dogs that underwent 90 to 120 minutes of fixed left anterior descending coronary artery (LAD) occlusion, and 8 dogs that underwent 90 minutes of temporary LAD occlusion and up to 90 minutes of reflow, 2 to 6 mCi of I-123 PPA were injected and the dogs were imaged with SPECT. Control dogs showed relatively uniform uptake and clearance of I-123 PPA in similar left ventricular (LV) regions. Dogs with permanent LAD occlusion were identified by computer algorithm as having regions of decreased I-123 PPA uptake in the infarct-related area and a reduced rate of I-123 PPA clearance (-9.4% in infarct sectors [washin], +3.7% in sectors adjacent to the area of infarction, and +15.4% in control LV sectors [p less than 0.01]). Dogs with temporary LAD occlusion and reperfusion had decreased clearance of I-123 PPA from the regions with infarction; I-123 PPA clearance was -5.2 +/- 16.4% in infarct sectors, 12.7 +/- 7.4% in periinfarct zones, and 30.4 +/- 12% in control LV regions. These data demonstrate that tomographic analysis of I-123 PPA uptake and clearance permits the relatively noninvasive detection of LV myocardium injured by permanent or temporary LAD occlusion and reperfusionon

337

Evaluation of the perfusion and contractile function of the myocardium using Karhunen-Loeve analysis in myocardial gated single photon emission computerized tomography  

International Nuclear Information System (INIS)

Goal: we evaluated the diagnostic performance of the Karhunen-Loeve transform applied to myocardial gated SPECT. The previous studies showed that K.L.T. images characterize myocardial perfusion (K.L.0) and contractile function (K.L.1). Method and material: 99 mTc-g SPECT studies were performed in 101 patients (121 acquisitions) with suspected or known coronary artery disease. The images were evaluated using a five-point scoring system dividing the left ventricle into 11 segments. We compared the scores obtained by this semi-quantitative visual analysis of g SPECT and K.L.T. images. Results and discussion: the agreement for perfusion and thickening scores was 94 and 95% respectively. Quantitative evaluation of K.L.0 and K.L.1 images by univariate and multivariate analysis was performed in the left ventricular R.O.I.. Discriminant analysis characterized the acquisitions as normal or pathologic with a sensitivity of 95% and a specificity of 96% and positive and negative predictive values of 96 and 95%. These selection criteria were tested prospectively in 52 patients with similar results. K.L.T. generates a synthesis of left ventricular perfusion and kinetics. It facilitates discrimination between normal and pathological acquisitions with high predictive values. (authors)

338

Myocardial technetium-99m sestamibi single-photon emission tomography as a prognostic tool in coronary artery disease: multivariate analysis in a long-term prospective study  

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A prospective study was started in 1988 and at present 176 consecutive, and thus unselected, patients have been enrolled. All of them have been submitted to stress-rest MIBI SPET for the diagnosis or evaluation of CAD; 147 patients (121 males and 26 females, aged 53{+-}9 years) have completed a surveillance period of at least 36 months following the scintigraphic study (range 36-60 months, mean 43). Sixty-one patients had a documented previous myocardial infarction. The mean pre-test likelihood of CAD was 44% in the patients without prior infarction. The main anamnestic, clinical, EKG and scintigraphic findings were evaluated and statistically correlated with the incidence of ensuing cardiac events using both univariate (chi-square test) and multivariate analysis (logistic regression model). Twenty-nine patients suffered from a cardiac event during the follow-up period (i.e. three cardiac deaths, six myocardial infarctions and 20 cases of unstable angina). Statistical multivariate analysis identified MIBI scan as the only highly significant and independent prognostic predictor. In detail, the most important scintigraphic parameters were the presence of a reversible defect and the extension of the stress perfusion defect. The presence of typical angina proved to be a slightly significant predictor, while no other examined parameter showed a significant correlation with a bad prognosis. In conclusion, MIBI SPET can be considered a useful tool in the risk stratification of CAD patients. (orig.). With 3 tabs.

Zanco, P. [Department of Nuclear Medicine, Castelfranco Veneto (Italy); Zampiero, A. [Department of Cardiology, Ospedale di Camposampiero (Italy); Favero, A. [Department of Statistics, Castelfranco Veneto (Italy); Borsato, N. [Department of Nuclear Medicine, Castelfranco Veneto (Italy); Chierichetti, F. [Department of Nuclear Medicine, Castelfranco Veneto (Italy); Rubello, D. [Department of Nuclear Medicine, Castelfranco Veneto (Italy); Saitta, B. [Department of Nuclear Medicine, Castelfranco Veneto (Italy); Ferlin, G. [Department of Nuclear Medicine, Castelfranco Veneto (Italy)

1995-09-01

339

Myocardial technetium-99m sestamibi single-photon emission tomography as a prognostic tool in coronary artery disease: multivariate analysis in a long-term prospective study  

International Nuclear Information System (INIS)

A prospective study was started in 1988 and at present 176 consecutive, and thus unselected, patients have been enrolled. All of them have been submitted to stress-rest MIBI SPET for the diagnosis or evaluation of CAD; 147 patients (121 males and 26 females, aged 53±9 years) have completed a surveillance period of at least 36 months following the scintigraphic study (range 36-60 months, mean 43). Sixty-one patients had a documented previous myocardial infarction. The mean pre-test likelihood of CAD was 44% in the patients without prior infarction. The main anamnestic, clinical, EKG and scintigraphic findings were evaluated and statistically correlated with the incidence of ensuing cardiac events using both univariate (chi-square test) and multivariate analysis (logistic regression model). Twenty-nine patients suffered from a cardiac event during the follow-up period (i.e. three cardiac deaths, six myocardial infarctions and 20 cases of unstable angina). Statistical multivariate analysis identified MIBI scan as the only highly significant and independent prognostic predictor. In detail, the most important scintigraphic parameters were the presence of a reversible defect and the extension of the stress perfusion defect. The presence of typical angina proved to be a slightly significant predictor, while no other examined parameter showed a significant correlation with a bad prognosis. In conclusion, MIBI SPET can be considered a useful tool in the risk stratification ofuseful tool in the risk stratification of CAD patients. (orig.). With 3 tabs

340

Therapeutic effect of co-enzyme Q10 on idiopathic dilated cardiomyopathy: assessment by iodine-123 labelled 15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid myocardial single-photon emission tomography  

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It has been reported that myocardial mitochondrial function can be improved by the administration of co-enzyme Q10 (CoQ10). Recently, iodine-123 labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) was developed for metabolic imaging using single-photon emission tomography (SPET). This study was conducted to determine whether the therapeutic effects of CoQ10 on idiopathic dilated cardiomyopathy can be evaluated by BMIPP myocardial SPET. Fifteen patients, comprising 14 men and one woman (mean age: 64{+-}12 years), were examined. CoQ10 was administered at 30 mg/day for a period of 35.7{+-}12.4 days. BMIPP myocardial SPET was carried out before and after CoQ10 treatment. The count ratio of the heart (H) to the upper mediastinum (M) (H/M ratio) was calculated using a region of interest method with anterior planar imaging. Representative short-axis tomograms were divided into 27 segments (three slices x nine segments). Each segmental score was analysed semiquantitatively using a four-point scoring system (normal=0, mild low uptake=1, severe low uptake=2, defect=3). The H/M ratio showed a significant improvement, from 2.39{+-}0.39 to 2.54{+-}0.47, after treatment (P<0.05). The BMIPP total defect score after CoQ10 treatment was significantly decreased to 10.1{+-}4.3, compared to 13.9{+-}4.5 without CoQ10 treatment (P<0.001). However, the percent fractional shortening measured using echocardiography was not significantly different before and after CoQ treatment (19.2{+-}8.1 vs 19.7{+-}7.1). BMIPP myocardial SPET was confirmed to be sensitive in evaluating the therapeutic effects of CoQ10 in patients with idiopathic dilated cardiomyopathy. This method is unique, since the therapeutic effects can be estimated from the perspective of metabolic SPET imaging. (orig.). With 5 figs., 1 tab.

Kim, Yong-ih [Department of Internal Medicine, Nishiyodo Hospital, Nishiyodo (Japan); Sawada, Yoshihiro [Department of Internal Medicine, Nishiyodo Hospital, Nishiyodo (Japan); Fujiwara, Go [Department of Radiology, Nishiyodo Hospital, Nishiyodo (Japan); Chiba, Hiroshi [Department of Internal Medicine, Mimihara General Hospital, Mimihara (Japan); Nishimura, Tsunehiko [Division of Tracer Kinetics, Biomedical Research Center, Osaka University Medical School, Osaka (Japan)

1997-06-10

 
 
 
 
341

Therapeutic effect of co-enzyme Q10 on idiopathic dilated cardiomyopathy: assessment by iodine-123 labelled 15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid myocardial single-photon emission tomography  

International Nuclear Information System (INIS)

It has been reported that myocardial mitochondrial function can be improved by the administration of co-enzyme Q10 (CoQ10). Recently, iodine-123 labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) was developed for metabolic imaging using single-photon emission tomography (SPET). This study was conducted to determine whether the therapeutic effects of CoQ10 on idiopathic dilated cardiomyopathy can be evaluated by BMIPP myocardial SPET. Fifteen patients, comprising 14 men and one woman (mean age: 64±12 years), were examined. CoQ10 was administered at 30 mg/day for a period of 35.7±12.4 days. BMIPP myocardial SPET was carried out before and after CoQ10 treatment. The count ratio of the heart (H) to the upper mediastinum (M) (H/M ratio) was calculated using a region of interest method with anterior planar imaging. Representative short-axis tomograms were divided into 27 segments (three slices x nine segments). Each segmental score was analysed semiquantitatively using a four-point scoring system (normal=0, mild low uptake=1, severe low uptake=2, defect=3). The H/M ratio showed a significant improvement, from 2.39±0.39 to 2.54±0.47, after treatment (P<0.05). The BMIPP total defect score after CoQ10 treatment was significantly decreased to 10.1±4.3, compared to 13.9±4.5 without CoQ10 treatment (P<0.001). However, the percent fractional shortening measured using echocardiography was not significantly different before and after CoQ treatment (19.2±8.1 and after CoQ treatment (19.2±8.1 vs 19.7±7.1). BMIPP myocardial SPET was confirmed to be sensitive in evaluating the therapeutic effects of CoQ10 in patients with idiopathic dilated cardiomyopathy. This method is unique, since the therapeutic effects can be estimated from the perspective of metabolic SPET imaging. (orig.). With 5 figs., 1 tab

342

Regional myocardial wall thickening and global ejection fraction in patients with low angiographic left ventricular ejection fraction assessed by visual and quantitative resting ECG-gated 99mTc-tetrofosmin single-photon emission tomography and magnetic resonance imaging  

International Nuclear Information System (INIS)

We investigated the use of visual and quantitative technetium 99m tetrofosmin ECG-gated single-photon emission tomography (SPET) for the assessment of regional myocardial wall thickening (WT) and left ventricular (LV) ejection fraction (EF) in comparison with gated magnetic resonance imaging (MRI) in patients with a low angiographic LVEF. Gated SPET using 99mTc-labelled flow tracers offers potential for simultaneous assessment of myocardial perfusion and LV function. Few data are available on the use of visual and quantitative gated SPET in patients with low LVEF. In this study 21 patients with low angiographic LVEF (mean 37%±5%) were studied. Resting gated 99mTc-tetrofosmin SPET and gated MRI were performed within 48 h. WT was assessed by visual interpretation (five point score) and quantitative analysis based on count increase. There was good agreement for EF measurements by MRI and gated SPET (mean EF: 33%±12% vs 35%±11%, r = 0.86, P<0.001). Areas under receiver operator characteristic curves (AUC) for differentiation between MRI WT score points ranged from 0.60 to 0.66 for visual SPET WT analysis, from 0.59 to 0.71 for delta count increase values and from 0.46 to 0.60 for % WT, indicating substantial overlap between WT categories. Absolute agreement for visual WT between MRI and gated SPET ranged from 25% to 57% (kappa 0.03-0.25) depending on tracer uptake, and was limited in areas with moderate to severe perfusion defects (kappa 0.03-0.13vere perfusion defects (kappa 0.03-0.13). It is concluded that gated SPET provided reliable estimates of regional WT and global function in patients with low angiographic LVEF. (orig.)

343

Kinetic analysis of 18F-fluorodihydrorotenone as a deposited myocardial flow tracer: Comparison to thallium-201.  

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The goal of this investigation was to assess the accuracy of 18F-fluorodihydrorotenone (18F-FDHR) as a new deposited myocardial flow tracer and compare the results to those for 201Tl. Methods. The kinetics of these flow tracers were evaluated in 22 isolated, erythrocyte- and albumin-perfused rabbit hearts over a flow range encountered in patients. The two flow tracers plus a vascular reference tracer (131I-albumin) were introduced as a bolus through a port just above the aortic cannula. Myocardial extraction, retention, washout, and uptake parameters were computed from the venous outflow curves using the multiple indicator dilution technique and spectral analysis. Results. The mean initial extraction fractions of 18F-FDHR (0.85 +- 0.07) and 201Tl (0.87 +- 0.05) were not significantly different, although the initial extraction fraction for 18F-FDHR declined with flow (P < 0.0001), whereas the initial extraction fraction of 201Tl did not. Washout of 201Tl was faster (P < 0.001) and more affected by flow (P < 0.05) than 18F-FDHR washout. Except for initial extraction fraction, 18F-FDHR retention was greater (P < 0.001) and less affected by flow (P < 0.05) than 201Tl retention. Reflecting its superior retention, net uptake of 18F-FDHR was better correlated with flow than 201Tl uptake at both one and fifteen minutes after tracer introduction (P < 0.0001 for both comparisons). Conclusion. The superior correlation of 18F-FDHR uptake with flow indicates that it is a better flow tracer than 201Tl in the isolated rabbit heart. Compared to the other currently available positron-emitting flow tracers (82Rb, 13N-ammonia, and 15O-water), 18F-FDHR has the potential of providing excellent image resolution without the need for an on-site cyclotron.

Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; O' Neil, James P.; La Belle, Michael; Huesman, Ronald H.; VanBrocklin, Henry F.

2004-03-01

344

Comparison of low-dose dobutamine stress echocardiography and single photon emission computed tomography and delayed contrast MRI in the diagnosis of myocardial viability: Meta-analysis  

International Nuclear Information System (INIS)

Objective: To assess the diagnostic value of different imaging methods including low- dose dobutamine stress echocardiography, SPECT and contrast enhancement MRI with Meta-analysis in the diagnosis of myocardial viability. Methods: Articles published from 1998 to 2008 were searched in Cochrane library, Medline, Embase database, OVID database and CNKI for relevant English and Chinese articles. According to the criteria for diagnostic research published by Cochrane Method Group on screening and diagnostic tests, each article was critically screened and appraised, including the absolute numbers of true-positive, false-negative, tree-negative, and false-positive. Statistical analysis was performed employing Meta-test. Heterogeneity was tested, pooled weighted sensitivity and specificity and the corresponding 95% CI were calculated. Characteristic (SROC) curve was performed and the area under the curve was calculated. Finally, sensitivity analysis was performed. Results: Twenty-one of 438 retrieved articles were included, in which there were ten articles about Low-dose dobutamine stress echocardiography, and six articles about 99Tcm-MIBL/99Tcm-Tetrofosmin SPECT, and six articles about contrast enhancement MRI, and one of both 99Tcm-MIBL/99Tcm-tetrofosmin SPECT and contrast enhancement MRI. All groups had heterogeneity, and a random effects regression was developed. The pooled weighted sssion was developed. The pooled weighted sensitivity and specificity and area under SROC curve for low-dose dobutamine stress echocardiography to diagnose myocardial viability was 0.73(0.62-0.82)/0.82 (0.77-0.86) and 87.07% respectively. They were 0.82 (0.59-0.94)/ 0.77 (0.64-0.86) and 86.97% for 99Tcm-MIBI/99Tcm-Tetrofosmin SPECT respectively, while they were 0.94 (0.86-0.97)/0.75 (0.66-0.83) and 91.41% for contrast enhancement MRI respectively. Conclusion: As noninvasive testing technologies, low-dose dobutamine stress echocardiography and 99Tcm-MIBI/99Tcm-tetrofosmin SPECT and delayed contrast enhanced MRI allow the identification of viable myocardium, but delayed contrast enhanced MRI showed significant different pooled sensitivity in comparison to low-dose dobutamine stress echocardiography. (authors)

345

Clinical studies on the thallium-201 myocardial scintiphotography in the patients with ischemic heart diseases  

International Nuclear Information System (INIS)

Thallium-201 (201Tl) myocardial scintiphotography was performed in 34 patients with myocardial infarction and 13 with angina pectoris. Changing pattern of 201Tl activity in various organs observed. Myocardial blood flow was calculated from the relation of these activities. The body surface radioactivity of 201Tl decreased rapidly in initial phase, it gradually slowed down then reached to plateau on the heart and the lungs, while it increased gradually on the liver and kidneys. In patients with congestive heart failure, blood clearance of 201Tl was delayed and radioactivity on the lung area was increased compared with normal case. MBF/CO (%) ratio was calculated by the following way. Soon after the injection of 201Tl, serial images including whole chest were taken one frame in each one second during 30 seconds. Total injected dose was calculated from the maximum radioactivity in the frame. Myocardial uptake was calculated by the anterior view subtracting the mediastinal activity as the background at 5 minutes after the injection. MBF/CO (%) ratio was calculated as th