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1

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)

2

Effects of smoking on myocardial injury in patients with conservatively treated acute myocardial infarction. A study with resting 123I-15-iodophenyl 3-methyl pentadecanoic acid/201Tl 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 123I-15-iodophenyl 3-methyl pentadecanoic acid (BMIPP)/201Tl 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 201Tl 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 201Tl between the current smoker and nonsmoker groups. The difference between the total defect scores for BMIPP and 201Tl 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/201Tl 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/201Tl mismatch, in AMI than nonsmokers. (author)

3

Usefulness of dual energy single photon emission computed tomography with 99mTc-pyrophosphate and 201TlCl in diagnosis of acute myocardial infarction  

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The dual energy single photon emission computed tomography (D-SPECT) with 99mTc-Pyrophosphate and 201TlCl was evaluated, using Bull's Eye Map representation in 30 patients with acute myocardial infarction. D-SPECT imaging for infarct detection was 100% sensitive. The patients were divided into two groups. One group had an overlap of accumulation of 99mTc and 201TlCl in the infarct zone and the other had no overlap. Fifteen of 19 patients (78.9%) in whom reperfusion was successful showed an overlap. Ten of 11 patients in whom reperfusion was unsuccessful showed no overlap. In the patients with successful reperfusion, the group that showed an overlap had a shorter interval between the onset of acute myocardial infarction and the reperfusion of coronary artery than the group that showed no overlap. But one case showed that collateral circulation had an influence on the overlap. In conclusion, using Bull's Eye Map representation, D-SPECT was useful to detect infarct and the overlap of accumulation of 99mTc and 201TlCl might be used as an index of early recanalization. (author)

4

Myocardial scintiscanning with 201Tl  

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In 130 patients a biphasic (rest and stress) scintigraphy of the myocard was accomplished with 201Tl. The reproducibility of the scintigraphic findings was fairly good. They were compared to one another as to the non-defect regions of interest (ROI), as to the reversible, and as to the irreversible defect ROI and with the adequate electrocardiograms. The method presented is suitable for diagnosis and localization of reversible, stress-dependent myocardial ischemia

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Evaluation of Agreement between 64-slice Computed Tomography Angiography and 201-Tl Single Photon Emission Computed Tomography-myocardial Perfusion Imaging in the Diagnosis of Significant Coronary Artery Disease  

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To compare coronary computed tomography angiography (CTA) with single photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) for the detection of physiologically significant coronary artery disease (CAD). We evaluated 202 patients undergoing 64-slice coronary CTA and 201-Tl SPECT-MPI within a 3-month time interval. In addition, 68 patients underwent invasive coronary angiography (ICA). Coronary artery stenoses with luminal narrowing {>=} 50% were defined as 'significant' on CTA and ICA. All myocardial segments were classified as reversible or fixed perfusion defects and normal segments on 201-Tl SPECT-MPI, and were allocated to the corresponding coronary vessels. Agreement and diagnostic performance between each imaging modality for physiologically significant CAD was calculated using the kappa ({kappa}) statistic and receiver operating characteristic analysis, respectively. The sensitivity and specificity of CTA for the detection of physiologically significant CAD were 88% and 86% by patient-based analysis, and 84% and 91% by vessel-based analysis as compared to 201-Tl SPECT-MPI, respectively. The agreement between CTA and SPECTMPI was good ({kappa} = 0.647) and moderate ({kappa} = 0.558) by patientand vessel-based analyses, respectively. The accuracy of CTA for predicting perfusion defects on SPECT-MPI was comparable (area under the curve; 0.814 vs. 0.819, p=0.902 on patient-based analysis, and 0.808 vs. 0.749, p=0.197 on vessel-based analysis) to ICA. Coronary stenosis {>=} 50% on coronary CTA shows good agreement with perfusion defects in SPECT-MPI.

Ma, Jee Hyun; Kang, Doo Kyoung [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Lee, Su Jin; An, Young Sil [Dept. of Nuclear Medicine, Ajou University School of Medicine, Suwon (Korea, Republic of); Lim, Hong Seok [Dept. of Cardiology, Ajou University School of Medicine, Suwon (Korea, Republic of)

2011-06-15

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Evaluation of Agreement between 64-slice Computed Tomography Angiography and 201-Tl Single Photon Emission Computed Tomography-myocardial Perfusion Imaging in the Diagnosis of Significant Coronary Artery Disease  

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To compare coronary computed tomography angiography (CTA) with single photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) for the detection of physiologically significant coronary artery disease (CAD). We evaluated 202 patients undergoing 64-slice coronary CTA and 201-Tl SPECT-MPI within a 3-month time interval. In addition, 68 patients underwent invasive coronary angiography (ICA). Coronary artery stenoses with luminal narrowing ? 50% were defined as 'significant' on CTA and ICA. All myocardial segments were classified as reversible or fixed perfusion defects and normal segments on 201-Tl SPECT-MPI, and were allocated to the corresponding coronary vessels. Agreement and diagnostic performance between each imaging modality for physiologically significant CAD was calculated using the kappa (?) statistic and receiver operating characteristic analysis, respectively. The sensitivity and specificity of CTA for the detection of physiologically significant CAD were 88% and 86% by patient-based analysis, and 84% and 91% by vessel-based analysis as compared to 201-Tl SPECT-MPI, respectively. The agreement between CTA and SPECTMPI was good (? = 0.647) and moderate (? = 0.558) by patientand vessel-based analyses, respectively. The accuracy of CTA for predicting perfusion defects on SPECT-MPI was comparable (area under the curve; 0.814 vs. 0.819, p=0.902 on patient-based analysis, and 0.808 vs. 0.749, p=0.197 on vessel-based analysis) to ICA. Coronaressel-based analysis) to ICA. Coronary stenosis ? 50% on coronary CTA shows good agreement with perfusion defects in SPECT-MPI.

7

Evaluation of visualized left atrium by 201Tl myocardial scintigraphy  

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201Tl myocardial scintigraphy was evaluated in patients with 18 mitral stenosis cases. Left atrium was to be seen in ANT (16.7 %), LAO (16.7 %), MLAO (16.7 %) and L-LAT (11.1 %), respectively. Furthermore, 201Tl uptake ratio of left atrium, right ventricle, pulmonary area tended significantly to increase in visible group compared with invisible group. PCW pressure was correlated with left atrial Tl uptake (r = 0.51, p 201Tl uptake. (author)

8

Assessment of transmyocardial laser revascularization by using {sup 201}Tl myocardial single photon emission computed tomography. A phase III multicenter trial  

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Tl myocardial SPECT was performed before TMLR and six months after in 40 cases. The improvement of myocardial perfusion was examined using semi-quantitative assessment method. The significant improvement of myocardial perfusion was recognized as the whole myocardium in both TMLR alone group (10 cases) and TMLR plus CABG group (30 cases). Improvement of myocardial perfusion was recognized in the regions which had TMLR, but the rate of improvement at the fixed defect before TMLR was lower than that at reversible defect. TMLR was useful for cases with diffuse coronary artery lesion which percutaneous transluminal coronary angioplasty and CABG can't be applied. (K.H.)

Nishimura, Tsunehiko [Osaka Univ., Suita (Japan). Graduate School of Medicine; Nohara, Ryuji; Nishida, Hiroshi; Koyanagi, Hitoshi

1999-06-01

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Evaluation of infantile ventricular tachycardia by 201Tl myocardial SPECT  

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201Tl myocardial SPECT findings in infantile ventricular tachycardia (VT) were examined. The subjects were 4 cases of infantile VT subjected exercise-loading 201Tl scintigraphy in 1990. These cases (3 males and 1 female) were aged 11-14 years, being persistent and non-persistent type VT (2 cases each). Echocardiography revealed no abnormal findings in these 4 cases. Exercise-loading was performed by means of sitting ergometer. ECG revealed sinus arrhythmia except for one case which throughout its course of treatment, had already been presenting ventricular extrasystole from before the excercise-loading. Myocardial SPECT revealed persistent defects (antero-septal wall defects in three cases). The above suggests that 201Tl myocardial SPECT enables us to search for etiology of VT, prognosis and the like. (author)

10

201Tl myocardial scintigraphy at rest and during exercise  

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64 patients (38 after myocardial infarction, 23 with angina pectoris, 3 controls) were examined by different methods of 201Tl myocardial scintigraphy: scintigraphy during exercise and redistribution scintigraphy, seaprate scintigraphy at rest and during exercise, and scintigraphy at rest followed by scintigraphy during exercise, resp. The scintigraphy during exercise and redistribution scintigraphy proved to be most effective in ischemic and dicatricial myocardium. The scintigraphy during exercise should be performed rapidly since the redistribution begins immediately after ischemia

11

Multi-center study for the evaluation of clinical usefulness of attenuation and scatter correction on 201Tl 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 201Tl myocardial single-photon emission computed tomography (201Tl SPECT) as a multi-center trial. With a dual-detector and a triple-detector SPECT systems with a 99mTc 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 201Tl distribution between male and female, significant decrease in 201Tl 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 201Tl 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 imat 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 201Tl distribution between male and female is improved in normal cases by attenuation and scatter correction on 201Tl 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 201Tl myocardial SPECT is considered to be clinically useful. (author)

12

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)

13

Quantitative evaluation of 201Tl myocardial SPECT  

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For a relative, quantitative evaluation of 201TI myocardial SPECT studies after stress and redistribution a program was developed which works on selected tomographic slices. A viability index (VI) and redistribution factor (RDF) were defined for quantitation, which were calculated for 8 myocardial sectors. Currently the method is employed to monitor the success of PTCA. In 18 patients studied a significant increase in VI and decrease of RDF was found. Compared to the visual evaluation an agreement in the findings was established in 5 patients and an improvement with remaining redistribution in 13 patients. (orig.)

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Scintigraphic detection of ischemic and other myocardial lesions using 201Tl  

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Current knowledge of the myocardium scintiscanning using 201Tl is briefly outlined. The principle is shown of 201Tl cumulation in a healthy myocardium and the use of the radionuclide is justified. Heart scintiscanning after exercise or after administration of drugs increasing the blood flow through the coronaries allows detecting latent ischaemic heart disease. 201Tl scintigraphy can also be used for diagnosing the myocardial infarction, angina pectoris and other heart diseases. (J.P.)

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Effects of smoking on lung uptake of 201Tl during exercise myocardial perfusion imaging  

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Objective: To investigate the influence of smoking on lung uptake of 201Tl during myocardial perfusion imaging. Methods: Ninety-two healthy subjects, with normal 201Tl myocardial perfusion imaging findings but no evidence of left ventricular hypertrophy and pulmonary disease, were divided into three groups, smoker, nonsmoker and quitted smoker groups. Exercise/delay 201Tl myocardial perfusion imaging was performed on all subjects included. Lung/heart ratio was defined on the anterior planar image obtained during exercise tomography. Results: Both the lung/heart ratios during exercise in smoker (0.40 ± 0.07, F=10.635, P201Tl lung/heart ratios in smokers are higher than in nonsmokers and this must be kept in mind when 201Tl lung/heart ratios are used clinically, even in quitted smokers

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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.)

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Correlation of myocardial uptake of 201Tl with local perfusion in the dog heart  

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34 anesthetized and thoracotomized dogs are studied. The local myocardial blood flow is measured with sup(99m)Tc human albumin microsphere. The intramyocardial distribution of 201Tl in relation to local blood flow is studied in basal conditions (24 dogs), after experimental infarction (4 dogs) and postischemic reactive hyperhemia (6 dogs). We conclude that during basal conditions, after infarction and hyperhemia the 201Tl myocardial distribution reflect with damping the variations of blood flow

18

Myocardial uptake of iodinated free fatty acids and 201Tl in experimental ischemia  

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In an experimental study, we evaluated the uptake of (131I)-17-iodo heptadecanoic acid (131I-HDA), (125I)-15-4 (4-iodophenyl) pentadecanoic acid (125I-PPA) and thallium-201 (201Tl) in the dog heart. Twenty dogs were studied and divided into 3 groups: in group A, 10 dogs (4 normal, 6 with coronary artery occlusion) were studied with 131I-HDA and 201Tl; in group B, 5 dogs (with occlusion) received 125I-PPA and 201Tl; and in group C, 5 dogs (with occlusion) were studied with 125I-PPA and 131I-HDA. Two min after administration of the compounds the hearts were excised and stored in formaldehyde. After sectioning of the left ventricle, total uptake was counted and expressed in percentage of injected dose. Uptake in the normal myocardium (group A) was 4.2+-0.6% for 131I-HDA and 4.6+-0.7% for 201Tl; in the occluded dog hearts (group A) we measured values of 2.6+-0.4% for 131I-HDA (p201Tl (p131I-HDA, 125I-PPA and 201Tl in groups B and C was not significantly different: group B, 125I-PPA 2.8+-0.8% and 201Tl 2.5+-0.5%; group C, 125I-PPA 1.9+-0.7% and 131I-HDA 1.6+-0.6%. Moreover, regional distribution of both iodinated fatty acids was quite comparable with the distribution of 201Tl. We cthe distribution of 201Tl. We conclude that 131I-HDA and 125I-PPA show similar uptake as 201Tl and are distributed according to coronary artery perfusion, which underscores their value as myocardial imaging agents. (orig.)

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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.)

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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.)

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Quantitative assessment of 201TlCl myocardial SPECT  

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Clinical evaluation of the quantitative analysis of Tl-201 myocardial tomography by SPECT (Single Photon Emission Computed Tomography) was performed in comparison with visual evaluation. The method of quantitative analysis has been already reported in our previous paper. In this study, the program of re-standardization in the case of lateral myocardial infarction was added. This program was useful mainly for the evaluation of lesions in the left circumflex coronary artery. Regarding the degree of diagnostic accuracy of myocardial infarction in general, quantitative evaluation of myocardial SPECT images was highest followed by visual evaluation of myocardial SPECT images, and visual evaluation of myocardial planar images. However, in the case of anterior myocardial infarction, visual evaluation of myocardial SPECT images has almost the same detectability as quantitative evaluation of myocardial SPECT images. In the case of infero-posterior myocardial infarction, quantitative evaluation was superior to visual evaluation. As for specificity, quantitative evaluation of SPECT images was slightly inferior to visual evaluation of SPECT images. An infarction map was made by quantitative analysis and this enabled us to determine the infarction site, extent and degree according to easily recognizable patterns. As a result, the responsible coronary artery lesion could be inferred correctly and the calculated infarction score could be correlated with the residual left ventricularrelated with the residual left ventricular function after myocardial infarction. (author)

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Diagnostic use of T2-weighted inversion-recovery magnetic resonance imaging in acute coronary syndromes compared with 99mTc-pyrophosphate, 123I-BMIPP and 201TlCl single photon emission computed tomography  

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The incidence of missed diagnoses of acute cardiac ischemia in the emergency department could be reduced by a new imaging modality. In the present study, the clinical significance of 99mTc-pyrophosphate (PYP), 123I-?-methyl-p-iodophenyl-pentadecanoic acid (BMIPP), 201TlCl scintigraphy (imaging) and T2-weighted inversion-recovery magnetic resonance imaging (MRI) for the detection of culprit lesion in patients with acute coronary syndromes (ACS) was compared. The study group comprised 18 patients with ACS: 12 patients with acute myocardial infarction (AMI) (11 males; mean age, 63±11 years) and 6 patients with unstable angina (UA) (3 males, mean age, 67±5 years). Of the 12 patients with AMI, 10 underwent 201TlCl and PYP single photon emission computed tomography (SPECT) studies as a dual-energy acquisition (201TlCl/PYP) and 8 underwent 201TlCl SPECT within 1 week of the BMIPP study. All 18 patients underwent BMIPP SPECT and MRI. The MRI pulse sequence was black blood turbo short-inversion-time inversion recovery (STIR) (breath-hold T2-weighted studies). The T2-weighted inversion-recovery MRI showed higher sensitivity and negative predictive value than PYP and 201TlCl, and higher specificity and positive predictive value than BMIPP and 201TlCl. The area under the receiver-operating characteristic curve for PYP, BMIPP, 201TlCl and MRI was 0.787, 0.725, 0.731 and 0.878, res was 0.787, 0.725, 0.731 and 0.878, respectively. The difference between the areas of MRI and BMIPP was significant (p<0.05). Accurate detection of culprit lesion is improved by using MRI rather than BMIPP, particularly for patients with ACS. (author)

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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)

24

Sequential change of cardiomyopathy of Duchenne muscular dystrophy by 201Tl myocardial SPECT  

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201Tl myocardial SPECT were performed to evaluate of cardiomyopathy in Duchenne type of progressive muscular dystrophy (DMD). Follow up SPECT images of the same patients were also obtained about 1 year after the first scan. Cases subjected to study were 10 DMD. At the first study the hypoperfusion area of the left ventricular muscle were observed in 6 cases (60%) out of 10. At the second study the hypoperfusion areas became wider and lower in 4 out of 6 cases (66.7%). The new hypoperfusion area which was not demonstrated at the first study was observed at the second study in one case of these cases. These results suggested that the positive rate of cardiomyopathy in DMD by 201Tl myocardial SPECT was high, and 201Tl myocardial SPECT is a useful examination to detect the change of myocardial damage in DMD. (author)

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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)

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Prognostic value of gated 201Tl myocardial perfusion SPECT imaging in patients with coronary artery disease  

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Objective: To study the prognostic value of gated 201Tl myocardial perfusion SPECT imaging in patients with coronary artery disease and assessment of therapy strategy for the individual patient. Methods: Eighty-four patients underwent rest and exercise stress 201Tl gated myocardial perfusion SPECT imaging and were followed up for (32.92 ± 16.77) months. Images were studied using 17 segments and 1 to 4 scoring. Global summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS=SSS-SRS) were also calculated. Post-stress and rest ejection fraction (EF) were automatically measured. Results: Nine cardiac events occurred (3.90% per year). SSS, SDS, SRS and EF were the independent predictors of cardiac events (P201Tl myocardial perfusion SPECT imaging can provide prognostic assessment for the patients with coronary artery disease and guide in selection of therapeutic strategy. Among all of the indices SSS is the best predictors of cardiac events. (authors)

27

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)

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Evaluation of coronary hemodynamics and exercise 201Tl-myocardial scintigraphy in patients with vasospastic angina  

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To clarify the coronary hemodynamics and myocardial perfusion in patients with vasospastic angina, we performed exercise 201Tl-myocardial scintigraphy (planar and SPECT) in 72 patients and left coronary digital subtraction angiography (DSA) in 37 patients without significant organic coronary artery stenosis. Coronary artery spasm was documented by coronary angiography in all patients. Fifty-four patients (75%) developed exercise-induced 201Tl-myocardial perfusion defect on SPECT. 201Tl pulmonary uptake (L/H) was significantly increased in patients with vasospastic angina. Especially, L/H was higher in patients with multiple small perfusion defect on 201Tl-SPECT, so that exercise-induced left ventricular dysfunction existed in patients with vasospastic angina and especially in cases of multiple small perfusion defect on 201Tl-SPECT. The left coronary circulation time (CCT) was prolonged in patients with vasospastic angina. The mechanism of prolonged CCT is still unknown, but we suspected that prolonged CCT was induced by increased peripheral coronary vascular resistance in patients with vasospastic angina. It was concluded that the peripheral coronary circulation was disturbed in patients with vasospastic angina, but its abnormal coronary circulation had no relation to location of spasm-induced vessels. We concluded that impaired coronary microcirculation was taken a part of pathophysiology in vasospastic angina. (f pathophysiology in vasospastic angina. (author)

29

Long term retention and excretion of 201Tl in a patient after myocardial perfusion imaging  

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201Tl is widely used in nuclear medicine to carry out myocardial perfusion imaging (MPI). However, very limited data is available on long-term distribution in the body, excretion and corresponding dose. In this study we performed a 2 month follow-up of a patient who underwent MPI, by urine analysis and in vivo measurements. The biological half-life of thallium was consequently estimated to be 11.6-27 d, which is in partial agreement with previous studies. We also estimated excretion and retention of 200Tl, 201Tl and 202Tl isotopes using the biokinetic parameters from ICRP publication 53 and compared the forecast result with actual measurements. The latter demonstrated a higher urinary excretion and a higher body retention than what was expected. Our results therefore suggest that the long-term retention and consequently the effective dose coefficient for 201Tl considered in ICRP publications 53 and 80 may be slightly underestimated. (authors)

30

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)

31

Potentialities of using 201Tl-chloride in the differential diagnosis of coronarogenic and extraconarogenic myocardial lesions in menopausal females  

International Nuclear Information System (INIS)

76 menopausal females were subjected to general clinical examination: biochemical investigation of carbohydrate, protein and lipid metabolism; radioimmunoassay of hormones; myocardial scintigraphy with 201Tl-chloride to diagnose coronarogenic and extracoronarogenic myocardial lesions. It is shown that the application of myocardial scintigraphy with 201Tl-chloride in menopausal females has followed to clarify the degree of distrophic changes in the myocardium of the left ventricle and to differentiate dyshormonal dystrophy and myocardial ischemia

32

Detection of coronary artery stenosis in children with Kawasaki disease. Usefulness of pharmacologic stress 201Tl myocardial tomography  

International Nuclear Information System (INIS)

This study determined the feasibility and accuracy of quantitative 201Tl myocardial single-photon emission computed tomography (SPECT) after dipyridamole infusion to detect coronary obstructive lesions in children with Kawasaki disease. 201Tl distribution after dipyridamole infusion was measured in 23 normal children, and with these normal values, quantitative analysis of SPECT was performed in 49 patients. Thirty-four patients had coronary stenosis 90% or greater on angiograms. Side effects resulting from systemic vasodilation were observed in about 70%. Angina pectoris and ischemic ST changes were observed only in patients with coronary stenosis. These symptoms disappeared after aminophylline infusion. Results of visual and quantitative analysis of SPECT were compared. SPECT data were shown on two-dimensional polar maps, and the extent and severity scores were calculated. The sensitivity of SPECT for detection of overall coronary stenosis was 91% (visual analysis) and 88% (quantitative analysis). The specificity of SPECT was 60% visually and 93% quantitatively. The sensitivity of quantitative analysis to detect individual coronary stenosis was similar to that of visual analysis. However, the specificity of visual analysis to detect individual coronary artery stenosis was significantly less than that of quantitative analysis. From these data, we conclude that quantitative analysis of myocardial SPECT after dipyridamole infusion is a safe and accurate diagnostic methoon is a safe and accurate diagnostic method for identifying coronary stenosis in children with Kawasaki disease

33

Studies on image diagnosis in multiple view and sequential myocardial scans with 201Tl  

International Nuclear Information System (INIS)

This study was carried out in order to evaluate (1) the accuracy and reproducibility of visual evaluation of 201 Tl scan image using three-dimensional myocardial phantoms, and (2) localization, sensitivity, specificity and accuracy of multiple view and sequential (delayed) 201Tl myocardial scans for detection of myocardial infarction in 168 cardiac and non-cardiac patients. From this study, the following results and conclusions were obtained. Detectability of defects in the static myocardial phantoms was best by the use of high-resolution collimator and poor by the use of magnifying amplifier or conversing collimator due to decrease in observed count density on scan images. Detectability of defects became poorer when moving phantoms were imaged. Visual evaluation of defects and its sequential changes correlated well with counting ratio derived from densitometry, and was shown to be accurate and reliable. On five view myocardial scans, score of the defect correlated well (p201Tl, the following criteria were concluded to be suitable for myocardial infarction; score of greater than or equal to 1.5 except apical defect and/or positive delayed scan. With this criteria, sensitivity, specificity, and accuracy for myocardial infarction were 88.3%, 95.4% and 92.9%, respfarction were 88.3%, 95.4% and 92.9%, respectively. (author)

34

Effect of wall thickness of left ventricle on 201Tl myocardial SPECT images. Myocardial phantom study  

International Nuclear Information System (INIS)

201Tl myocardial SPECT is known for better sensitivity, specificity, and accuracy than planar images in detecting coronary artery disease and diagnosing myocardial viability. SPECT images arc also superior to planar images in diagnostic sensitivity and anatomical orientation. However, as limitation of the spatial resolution of the machine, we often encounter poor SPECT plower image quality in patients with decreased wall thickness. To test the accuracy of SPECT images in patients with marked thinning of the left ventricular wall, as occurs in dilated cardiomyopathy, we performed a experimental study using myocardial phantom with 7 mm wall thickness. Tomographic image of the phantom images were rather heterogeneous, though no artificial defect was located Dilated cardiomyopathy is thought to be characterized by patchy defects in the left ventricle. Careful attention should be given to elucidating myocardial perfusion in patients with a thin left ventricle wall, as there are technical limitations in addition to clinical features. (author)

35

Contamination of clothing and other items by sweat during exercise 201Tl myocardial perfusion scintigraphy  

International Nuclear Information System (INIS)

We measured the radioactivity on patient's upper and lower garments, towels, broad sashes for the bust, and electrodes contaminated by sweat due to exercise 201Tl myocardial perfusion scintigraphy. In measuring activity, a scintillation survey meter adjusted to the energy of 201Tl was used. In measuring the radioactivity of clothing, more than 4 Bq/cm2 was considered to be a significant level of contamination. We detected contamination in 30% of upper garments and towels, 19% of broad sashes, 8% of lower garments and 4% of electrodes. Among these materials, several items of clothing and other items showed contamination exceeding 40 Bq/cm2. Towels were remarkably contaminated, with one towel showing a maximum contamination level of 420 Bq/cm2. Examinations done by exercise 201Tl myocardial perfusion scintigraphy often result in the contamination of clothing and other items through sweating. This contamination is especially common in summer, particularly in upper garments and towels. The contamination ratio for towels was over 50%. The contamination ratio increased as the level of exercise became more difficult. When the exercise load was more than 100 W, the contamination ratio was 50%. In cases of extreme contamination, images of contaminated upper garments could be obtained by the scintigraphy camera. The areas of high activity on the images seemed to correspond to areas of the body where sweating was d to areas of the body where sweating was profuse. Based on these results, we should pay close attention to the handling of clothing and other items used in exercise testing by 201Tl myocardial perfusion scintigraphy and the points used in measuring contaminated clothing and other items after testing. (author)

36

Contamination of clothing and other items by sweat during exercise {sup 201}Tl myocardial perfusion scintigraphy  

Energy Technology Data Exchange (ETDEWEB)

We measured the radioactivity on patient`s upper and lower garments, towels, broad sashes for the bust, and electrodes contaminated by sweat due to exercise {sup 201}Tl myocardial perfusion scintigraphy. In measuring activity, a scintillation survey meter adjusted to the energy of {sup 201}Tl was used. In measuring the radioactivity of clothing, more than 4 Bq/cm{sup 2} was considered to be a significant level of contamination. We detected contamination in 30% of upper garments and towels, 19% of broad sashes, 8% of lower garments and 4% of electrodes. Among these materials, several items of clothing and other items showed contamination exceeding 40 Bq/cm{sup 2}. Towels were remarkably contaminated, with one towel showing a maximum contamination level of 420 Bq/cm{sup 2}. Examinations done by exercise {sup 201}Tl myocardial perfusion scintigraphy often result in the contamination of clothing and other items through sweating. This contamination is especially common in summer, particularly in upper garments and towels. The contamination ratio for towels was over 50%. The contamination ratio increased as the level of exercise became more difficult. When the exercise load was more than 100 W, the contamination ratio was 50%. In cases of extreme contamination, images of contaminated upper garments could be obtained by the scintigraphy camera. The areas of high activity on the images seemed to correspond to areas of the body where sweating was profuse. Based on these results, we should pay close attention to the handling of clothing and other items used in exercise testing by {sup 201}Tl myocardial perfusion scintigraphy and the points used in measuring contaminated clothing and other items after testing. (author)

Yokoo, Shigeki; Niio, Yasuo; Yamamoto, Tomoaki; Miyashita, Makoto [Showa Univ., Yokohama (Japan). Fujigaoka Hospital

1999-05-01

37

Relation between regional distribution of 201Tl and myocardial blood flow in normal, acutely ischemic, and infarcted myocardium  

International Nuclear Information System (INIS)

Myocardial localization of 201Tl was compared with direct measurements of myocardial perfusion in normal, acutely ischemic, and recently infarcted myocardium. Studies were performed in 6 chronically instrumented dogs that were subjected to myocardial infarction by occlusion of the proximal left circumflex coronary artery. Four days after myocardial infarction, 201Tl and 9 +/- 1 micrometer 95Nb-labelled microspheres were injected simultaneously after acute left anterior descending coronary arterial occlusion; the animals were killed 5 minutes later and the entire left ventricle was sectioned into 1 to 2 g samples. Regression analyses between 201Tl activity and regional myocardial blood flow using all myocardial samples demonstrated a very close linear relation in each dog; r values were 0.98 or greater, indicating that the initial localization of 201Tl in acutely ischemic and recently infarcted myocardium as a function of regional blood flow was essentially identical. Consequently, in each dog the regional distribution of 201Tl closely approximated myocardial perfusion over a wide range of blood flow and potentially different local metabolic conditions that may be encountered in the clinical use of the isotope

38

Gamma radiation measurements and Monte Carlo computations following myocardial perfusion imaging with 201Tl  

International Nuclear Information System (INIS)

In the current study, the time-dependent retention of 201Tl-thallous chloride (111 MBq) was measured in a 56-y-old man undergoing myocardial perfusion imaging. For 23 d following the 201Tl injection, total-body retained activity was measured by (i) in situ gamma spectrometry using a portable high-purity germanium (HPGe) detector and (ii) ex vivo urine radioassay using a shielded HPGe detector. The time-dependent decrease in total-body activity followed a monoexponential function, exp(-0.011 t), with an excellent correlation (R2=0.9988) between the experimental data and the fitted values. The effective half-life, Teff, of 201Tl (physical half-life, Tph: 72.9 h) was therefore 63 h and the biological half-life, Tb, 463 h=19.3 d, identical to those measured in the same patient in 1997 (i.e. 14 y ago). The time-dependent decrease in the urine activity concentration, which followed a monoexponential function, exp(-0.0115 t), corroborated the foregoing results. The correlation (R2=0.9939) between the experimental data and the fitted values was again excellent. The effective half-life, Teff, was 60.26 h and the biological half-life, Tb, 348 h = 14.5 d. Monte Carlo simulation using a simple model of the patient as a unit-density cylinder filled with water and containing a uniform distribution of 201Tl yielded photon flux results in reasonable agreement with the measured data. (authors)data. (authors)

39

Gamma radiation measurements and Monte Carlo computations following myocardial perfusion imaging with 201Tl.  

Science.gov (United States)

In the current study, the time-dependent retention of (201)Tl-thallous chloride (111 MBq) was measured in a 56-y-old man undergoing myocardial perfusion imaging. For 23 d following the (201)Tl injection, total-body retained activity was measured by (i) in situ gamma spectrometry using a portable high-purity germanium (HPGe) detector and (ii) ex vivo urine radioassay using a shielded HPGe detector. The time-dependent decrease in total-body activity followed a monoexponential function, exp(-0.011 t), with an excellent correlation (R(2)=0.9988) between the experimental data and the fitted values. The effective half-life, Teff, of (201)Tl (physical half-life, Tph: 72.9 h) was therefore 63 h and the biological half-life, Tb, 463 h=19.3 d, identical to those measured in the same patient in 1997 (i.e. 14 y ago). The time-dependent decrease in the urine activity concentration, which followed a monoexponential function, exp(-0.0115 t), corroborated the foregoing results. The correlation (R(2)=0.9939) between the experimental data and the fitted values was again excellent. The effective half-life, Teff, was 60.26 h and the biological half-life, Tb, 348 h=14.5 d. Monte Carlo simulation using a simple model of the patient as a unit-density cylinder filled with water and containing a uniform distribution of (201)Tl yielded photon flux results in reasonable agreement with the measured data. PMID:22611205

Clouvas, A; Xanthos, S

2012-12-01

40

The clinical study of the myocardial scintigraphy used by 201Tl  

International Nuclear Information System (INIS)

Myocardial scintigraphy was performed with 201Tl. The results were analyzed according to followings: (1) analyses of myocardial scintigrams from controls, (2) relationship between this scintigram and ECG in the patient with myocardial infarction, (3) comparison of myocardial scintigrams from the patients with congestive cardiopathy with those from hypertrophic cardiopathy. (1) In controls, the images showed homogenous accumulation of the radioisotopes and shape either of horseshoe in anterior or left lateral view, or of circle or oval in left anterior 450 oblique view. (2) In many patients with myocardial infarction, the infarcted area suggested by ECG was coincided with that by scintigram and the scintigram was suggested to be useful as one of the diagnostic techniques. However, it is difficult to identify the infarcted area in some patients with widespread infarction. (3) The scintigram was more effective to diagnose hypertrophic cardiopathy. (Nishio, M.)

41

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  

International Nuclear Information System (INIS)

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 (201Tl) myocardial single photon emission computed tomography (SPECT) and electrocardiographic analysis in the subacute phase. The relationship between BMIPP and 201Tl was defined as match when the total defect score for BMIPP was equal to or smaller than that for 201Tl, and as mismatch when the total defect score for BMIPP was larger than that for 201Tl. Twenty-six patients (21%) demonstrated BMIPP-201Tl match and 97 (79%) demonstrated mismatch. Infarct size was closely correlated with QT dispersion (r=0.67, p201Tl match, but weakly correlated (r=0.30, p201Tl mismatch. For small infarctions, QT dispersion was significantly larger in patients with BMIPP-201Tl mismatch than in those with BMIPP-201Tl 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 patienischemic but viable myocardium in patients with AMI. (author)

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

Comparison of correction techniques for simultaneous 201Tl/99mTc myocardial perfusion SPECT imaging: a dog study  

International Nuclear Information System (INIS)

We compared two correction methods for simultaneous 201Tl/99mTc 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 201Tl and 99mTc. The first approach, described by Moore et al, corrects only for the contribution of the 99mTc to the 201Tl 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 201Tl/99mTc sestamibi cardiac dog study. Three separate acquisitions were performed in this dog study: two single-isotope and one dual-isotope acquisition. The 201Tl 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 (201Tl + 99mTc) and single-isotope (201Tl-only) 70 keV images, respectively. The corrected dual-isotope images had 514 700 ± 700 and 368 otope 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 201Tl 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 201Tl-only 70 keV images. (author)

44

Clinical evaluation of {sup 201}Tl single photon emission computed tomography in patients with large opacities due to silicosis and in those with bronchogenic carcinoma  

Energy Technology Data Exchange (ETDEWEB)

{sup 201}Tl single photon emission computed tomography ({sup 201}Tl SPECT) was used to evaluate 18 patients with large opacities due to silicosis and 22 others with bronchogenic carcinoma. An early scan and a delayed scan were obtained and the retention index was calculated from the early ratio and the delayed ratio. In patients with silicosis, the retention index and the two ratios were significantly lower than in the patients with bronchogenic carcinoma (p<0.01). In patients with stable shadows on chest X-ray films due to large opacities of silicosis, the delayed ratio was the same as or lower than the early ratio. However, in patients with silicosis who had high activity in large opacities, the delayed ratio was higher than the early ratio. These results suggest that {sup 201}Tl SPECT is useful for evaluating the activity of large opacities in patients with silicosis and for differentiating large opacities caused by silicosis from those caused by bronchogenic carcinoma. (author)

Sunami, Koji; Kishimoto, Takumi; Yonei, Toshiro; Ozaki, Shinji; Kimura, Kazuhi; Fujioka, Hideki; Ohke, Masashi; Ohnoshi, Taisuke [Okayama Rousai Hospital (Japan)

1996-06-01

45

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

Energy Technology Data Exchange (ETDEWEB)

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

46

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

International Nuclear Information System (INIS)

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

47

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.)

48

Crosstalk analysis of simultaneously acquired dual-isotope 201tl myocardial perfusion SPECT and 99Tcm-RBC equilibrium ventricle imaging  

International Nuclear Information System (INIS)

Objective: To analysis the crosstalk between the 20'1Tl and 99Tcm while the myocardial SPECT imaging with 201Tl and the equilibrium ventricle imaging with 99Tcm-RBC are simultaneously acquired, and to search after a method to reduce the down scatter of 99Tcm in the 201Tl window. Methods: Myocardial perfusion images were acquired using a cardiac phantom, which can present various levels of ischemia. The pulse height analysis was performed before the SPECT acquisition. The down scatter ratio of different 201Tl doses was calculated on each project with variable acquisition energy window. After the raw data were reconstructed with Butterworth filter, the defect-to-myocardium count ratios from different 201Tl acquisition window and variable defect levels were compared. Results: During the dual-isotope acquisition with 201Tl and 99Tcm the main crosstalk was the down scatter of 99Tcm in 201Tl window, which was considerably reduced while using higher dosage of 201Tl. The down scatter was also inhibited by applying more specific energy window of 201Tl. The defect-to-myocardium ratio analysis showed that only the data acquired under 15% energy window were affected on the contrast of the defects in short axis slice. The window of 201Tl and the extent of the ischeup>201Tl and the extent of the ischemia influenced the defect-to-myocardium ratios of mimic ischemia segments differently. The completely defect group appeared insensible to the change of acquisition window. Between the defect-to-myocardium ratio of 33% filled group and the 66% filled group considerable difference was demonstrated while the acquisition window of 20% was used. Conclusions: The down scatter of 99Tcm is the major factor which influences the simultaneous dual-isotope acquisition. The stain can be reduced either using more specific 201Tl energy acquisition window or applying higher dosage of 201Tl. But due to the long half-life of 201Tl, the authors can not increase the dosage discretionarily. As the more specific window of 201Tl can avoid the influence of the judgement of defect, and provide higher resolution of images, the authors recommend +-10% 201Tl energy window for 201Tl/99Tcm simultaneous acquisition

49

Study of washout rate in patients with chronic renal failure by dipyridamole 201Tl myocardial scintigraphy  

International Nuclear Information System (INIS)

Fourteen patients with chronic renal failure (CRF) were studied by dipyridamole 201Tl myocardial scintigraphy. In this study, patients with coronary heart disease were excluded by clinical findings. 201Tl SPECT was performed at 8 min after injection of dipyridamole (0.56 mg/kg) and at a 3-hr delayed interval, and washout rates (WR) were calculated. Because UCG showed left ventricular hypertrophy (thickness; 13±2 mm) in CRF, the WR values were compared with those of hypertrophic cardiomyopathy (HCM)(n=9). In CRF, an average WR was 54.2±6.8% and was significantly higher than that in normal (46.2±9.1%, p<0.05, n=9), though WR in HCM was significantly low (26.9±11.4%, p<0.01). Hematocrit value was 24.5±3.2% in CRF and was significantly lower than that in normal (37.8±3.6%, p<0.001). On the other hand, hemoconcentration was observed in HCM (hematocrit; 44.6±3.6%, p<0.001). WR in CRF, HCM and normal had significant correlation with hematocrit values (r=-0.796, p<0.001). These results suggest that anemia or hemoconcentration may affect coronary blood flow and WR, and this should be considered when diagnosing coronary heart disease in CRF or HCM. (author)

50

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.)

51

Myocardial imaging with 201Tl at rest and during exercise. Comparison with coronary arteriography and resting and stress electrocardiography  

International Nuclear Information System (INIS)

Myocardial imaging with intravenous thallium-201 (201Tl) was performed at rest and following maximal treadmill exercise in 101 patients with suspected coronary artery disease. Results were interpreted from Polaroid scintiphotos by three independent observers with complete interobserver agreement in 79%. Of 25 patients with no or insignificant coronary artery disease (201Tl image defect, one (4%) had an exercise 201Tl defect, none had an ECG Q wave, and four (16%) had exercise ST-segment depression. Among 76 patients with coronary artery disease (greater than or equal to 50% diameter stenosis), 58 (76%) had a defect on either the rest or exercise 201Tl image. The proportion of patients with an exercise image defect (50/76, 66%) was greater than the proportion with exercise ST depression alone (34/76, 45%; P 201Tl is easily accomplished with readily available imaging equipment. The image data enhanced the diagnostic sensitivity of stress electrocardiography, and provided spatial identificrdiography, and provided spatial identification of the abnormal segment(s) of myocardium

52

Noninvasive detection and localization of coronary stenoses in patients: comparison of resting dipyridamole and exercise 201Tl myocardial perfusion imaging  

International Nuclear Information System (INIS)

Two noninvasive tests to detect and localize coronary stenoses were compared in a fully blinded protocol. 201Tl myocardial perfusion imaging (MPI) following maximal treadmill exercise and pharmacologic coronary vasodilation with intravenous dipyridamole (DP) was performed in 33 patients. 201Tl imaging defects in six myocardial perfusion regions were correlated with stenoses in their respective vascular distributions. Disease severity was determined with coronary arteriograms using a computer-assisted method. 198 myocardial regions were evaluated; 101 were supplied by at least one major artery with a greater than or equal to 50% stenosis (luminal diameter narrowing). The sensitivity and specificity for detecting a greater than or equal to 50% stenosis were 85% and 64% (p less than 0.005), respectively, for DP and 84% and 68% (p less than 0.005) for exercise-201Tl imaging. A particular combination of anterior and septal imaging defects was useful in detecting left anterior descending artery stenoses proximal to its first septal branch. DP administration was safe in this group of patients; however, 42% experienced transient chest pain. Although the overall sensitivity and specificity of the two methods were not significantly different, DP-MPI appeared more sensitive than exercise-MPI (70% vs 52%, p less than 0.01) in detecting coronary stenoses in the 40% to 60% range. DP-201Tl MPI provides a useful alternative test for potentiides a useful alternative test for potential coronary disease patients unable to perform maximal exercise

53

Specific perfusion pattern in stress 201Tl myocardial scintigraphy of left main coronary artery disease  

International Nuclear Information System (INIS)

The usefulness of stress 201Tl myocardial scintigraphy for identifying left main coronary artery disease was evaluated with data from 23 patients with 50% or more narrowing of the left main coronary artery and 56 patients with 75% or more narrowing of the major coronary arteries but without left main coronary artery involvement (no left main coronary artery disease). Quantitative evaluation of stress perfusion scintigrams in all five patients with narrowing of the left main coronary artery of 90% or more showed a characteristic perfusion pattern (left main pattern) of extensive homogeneous defect over the whole anterolateral segment and simultaneous defects in all radii of the high anteroseptal and high posterolateral segments. On the other hand, such a perfusion pattern was noted in only 1 of 18 patients with less than 90% stenosis of the left main coronary artery and in only 1 of 56 patients with no left coronary artery disease. (orig.)

54

Observer performance with computer-generated images of 201Tl-Cl myocardial perfusion  

International Nuclear Information System (INIS)

The effect of simple image processing on the interpretation of 201Tl-Cl myocardial perfusion images was evaluated by ROC analysis. Polaroid images of the cathode ray tube of an Anger camera and computer-processed transparent images recorded in color and shades of gray were examined by multiple observers. A total of 198 observer responses was accumulated for each of five image formats. The observer responses were compared with results established by coronary angiography. Better observer performance was obtained for all computer-generated images except in the region of low false positive values. The response for color-scale formats were, in general, superior to those from the gray-scale formats. No significant improvement in observer performance resulted from the use of background subtraction with a rescaling of the 16-level gray scale to the residual information. When nine-point smoothing was applied to the color-scale display format, there was a poorer observer response

55

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

International Nuclear Information System (INIS)

201Tl has been extensively used for myocardial perfusion and viability assessment. Unlike 99mTc-labelled agents, such as 99mTc-sestamibi and 99mTc-tetrofosmine, the regional concentration of 201Tl 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 201Tl using dynamic SPECT. Dynamic SPECT was carried out on 20 normal canines after the intravenous administration of 201Tl 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 (K1) 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 obtacompared to a resting condition. MBFs obtained with SPECT (MBFSPECT) correlated well with the MBF values obtained by the radio-labelled microspheres (MBFMS) (MBFSPECT = -0.067 + 1.042 x MBFMS, p 201Tl and dynamic SPECT. (orig.)

56

Effects of diltiazem in patients with ischemic heart disease evaluation by exercise stress test and 201Tl myocardial scintigraphy  

International Nuclear Information System (INIS)

In 15 ischemic heart disease patients including 6 with myocardial infarction, the effect of Diltiazem, a Ca-antagonist, was evaluated by exercise stress tests using an ergometer and by exercise stress 201Tl myocardial scintigraphy. Administration of Diltiazem significantly increased the exercise tolerance time from 6.6 +- 3.3 min. to 8.5 +- 3.2 min. (p 0.01). During exercise stress, heart rate was significantly decreased below the level of the controls and rate-pressure product, which is considered to be oxygen consumption index, was also decreased, while no significant change occurred in systolic pressure. Exercise stress 201Tl myocardial scintigraphy revealed some improvement of the defect in 5 of 8 cases. (Ueda, J.)

57

Effect of wall thickness of left ventricle on {sup 201}Tl myocardial SPECT images. Myocardial phantom study  

Energy Technology Data Exchange (ETDEWEB)

{sup 201}Tl myocardial SPECT is known for better sensitivity, specificity, and accuracy than planar images in detecting coronary artery disease and diagnosing myocardial viability. SPECT images arc also superior to planar images in diagnostic sensitivity and anatomical orientation. However, as limitation of the spatial resolution of the machine, we often encounter poor SPECT plower image quality in patients with decreased wall thickness. To test the accuracy of SPECT images in patients with marked thinning of the left ventricular wall, as occurs in dilated cardiomyopathy, we performed a experimental study using myocardial phantom with 7 mm wall thickness. Tomographic image of the phantom images were rather heterogeneous, though no artificial defect was located Dilated cardiomyopathy is thought to be characterized by patchy defects in the left ventricle. Careful attention should be given to elucidating myocardial perfusion in patients with a thin left ventricle wall, as there are technical limitations in addition to clinical features. (author)

Koto, Masanobu; Kawase, Osami [Kobe Univ. (Japan). Hospital; Namura, Hiroyuki; Yamasaki, Katsuhito; Kono, Michio

1996-07-01

58

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)

59

Development of normal limits for left ventricular ejection fraction measured from gated myocardial perfusion SPECT with 99Tcm-MIBI and 201Tl  

International Nuclear Information System (INIS)

Objective: To develop normal limits for left ventricular ejection fraction (LVEF) measured from gated myocardial perfusion SPECT with 99Tcm-methoxyisobutylisonitrile (MIBI) and 201Tl. Methods: Gated myocardial perfusion SPECT with 99Tcm-MIBI and 20'1Tl was performed on 277 patients with a low Bayesian likelihood (99Tcm-MIBI [normotensive subgroup: n=85; hypertension without left ventricular hypertrophy (LVH) subgroup: n=25] and 201Tl(n=167, normotensive subgroup: n=128; hypertension without LVH subgroup: n=39). The resting LVEF was calculated using an automatic gated myocardial perfusion SPECT processing software. Results: The hypertension without LVH subgroup had significantly higher resting LVEF values compared with normotensive subgroup (P99Tcm-MIBI group and 20'1Tl group. Sex differences were marked: men had significantly lower mean resting LVEF values than women (P0.05). The distributions for resting LVEF values in 99Tcm-MIBI group and 201Tl group were Gaussian (P>0.05). The normal limits were LVEF?45% in 99Tcm-MIBI (?45% in men, ?48% in women) and ?43% in 201Tl (?42% in men, ?47>201Tl (?42% in men, ?47% in women) Conclusion: These normal limits can be evaluated prospectively for their potential clinical value

60

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.)

61

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)

62

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)

63

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)

64

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

Energy Technology Data Exchange (ETDEWEB)

We performed stress {sup 201}Tl myocardial SPECT to evaluate ischemia and perfusion reserve after coronary artery bypass grafting (CABG). A total of 103 patients was performed stress {sup 201}Tl 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 {sup 201}Tl defect, however, 36 of 117 (30.8%) segments which covered by patent arterial grafts showed reversible {sup 201}Tl 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)

Ichikawa, Akihiro; Taki, Junichi; Nakajima, Kenichi; Kawasuji, Michio; Tonami, Norihisa [Kanazawa Univ. (Japan). School of Medicine

1997-01-01

65

Processing of 201Tl serial images for the assessment of myocardial clearance and redistribution  

International Nuclear Information System (INIS)

Regional activity changes over the myocardium after IV injection of 201Tl were assessed in 90 patients by applying a superposition algorithm for paired images. The kinetics were expressed as quotients C1/C2 of the initial divided by the delayed count rate within an myocardial segment. Regarding the total left ventricular myocardium, normal subjects showed count rate ratios (Csub(30 min)/C4sub(h)) of 1.75 +- 0.075 (SD, n = 19) when the nuclide was injected under submaximal (80% of maximum) exercise. In patients with triple-vessel disease (n = 21) the corresponding values were 1.46 +- 0.05, in single-vessel (n = 14) disease the quotients averaged 1.62 +- 0.12. Average quotients in poststenotic myocardial segments increased from 1.46 before to 1.73 following bypass surgery in cases of graft patency (n = 8), while a decrease was observed in a patient with occlusion of the bypass graft. In small-vessel disease and in congestive cardiomyopathy, global values of 1.50 +- 0.07 (n = 7) and 1.53 +- 0.12 (n = 19) were obtained. The display of C1/C2 matrices provided typical patterns in uptake defects caused by ischemic heart disease and by congestive cardiomyopathy. The procedure described may provide diagnostic information in addition to conventional myocardial scintigrphy in triple-vessel disease, in patients with angina who fail to demonstrate hemodynamically significant coronary artery stenoses, and in patients coronary artery stenoses, and in patients with inhomogeneous Tl-scintigrams. (orig.)

66

Cost-effectiveness of exercise 201Tl myocardial SPECT in patients with chest pain assessed by decision-tree analysis  

International Nuclear Information System (INIS)

To evaluate the potential cost-effectiveness of exercise 201Tl myocardial SPECT in outpatients with angina-like chest pain, we developed a decision-tree model which comprises three 1000-patients groups, i.e., a coronary arteriography (CAG) group, a follow-up group, and a SPECT group, and total cost and cardiac events, including cardiac deaths, were calculated. Variables used for the decision-tree analysis were obtained from references and the data available at out hospital. The sensitivity and specificity of 201Tl SPECT for diagnosing angina pectoris, and its prevalence were assumed to be 95%, 85%, and 33%, respectively. The mean costs were 84.9 x 104 yen/patient in the CAG group, 30.2 x 104 yen/patient in the follow-up group, and 71.0 x 104 yen/patient in the SPECT group. The numbers of cardiac events and cardiac deaths were 56 and 15, respectively in the CAG group, 264 and 81 in the follow-up group, and 65 and 17 in the SPECT group. SPECT increases cardiac events and cardiac deaths by 0.9% and 0.2%, but it reduces the number of CAG studies by 50.3%, and saves 13.8 x 104 yen/patient, as compared to the CAG group. In conclusion, the exercise 201Tl myocardial SPECT strategy for patients with chest pain has the potential to reduce health care costs in Japan. (author)

67

Clinical implications of increased lung uptake of 201Tl during exercise scintigraphy 2 weeks after myocardial infarction  

International Nuclear Information System (INIS)

To determine the prevalence and clinical significance of increased lung 201Tl uptake during submaximal exercise myocardial scintigraphy performed 2 weeks after acute myocardial infarction, 61 patients underwent submaximal exercise testing (target heart rate, 120 beats/min), multigated blood pool imaging at rest and coronary angiography before hospital discharge. Thallium lung uptake on the initial anterior projection image was graded qualitatively by comparing the intensity of 201Tl activity in the lungs with that in the mediastinum. In 39 patients (64 percent), it was normal (equal to mediastinal activity) and in 22 (36 percent), it was increased (greater than mediastinal activity). Compared with patients with normal lung uptake, those with increased uptake had a greater prevalence of prior infarction (13 versus 36 percent, probability [p] less than 0.05), less global cardiac reserve as assessed by the four level New York Heart Association classification (p less than 0.05), more advanced Killip class in the coronary care unit (p less than 0.05), a higher Norris coronary prognostic index (2.6 +/- 1.9 versus 4.6 +/- 2.3 [mean +/- standard deviation], p less than 0.01), failure to achieve the target heart rate because of dyspnea, fatigue or angina (36 versus 86 percent, p less than 0.01), a greater prevalence of exercise-induced S-T segment depression (18 versus 45 percent, p less than 0.05), a greater number of anterior 201Tl myocardialer of anterior 201Tl myocardial defects (p less than 0.05); a lower radionuclide ejection fraction at rest (50.4 +/- 6.1 versus 39.6 +/- 9.3 percent, p less than 0.01) and a greater number of asynergic left ventricular segments (p less than 0.05). Thus, the occurrence of increased lung 201Tl uptake during submaximal exercise scintigraphy in the early postinfarction period is frequent and appears to be a marker of severe and functionally more important coronary artery disease associated with left ventricular dysfunction

68

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)

69

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

70

Low-dose single acquisition rest {sup 99m}Tc/stress {sup 201}Tl myocardial perfusion SPECT protocol: phantom studies and clinical validation  

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We developed and tested a single acquisition rest {sup 99m}Tc-sestamibi/stress {sup 201}Tl dual isotope protocol (SDI) with the intention of improving the clinical workflow and patient comfort of myocardial perfusion single photon emission computed tomography (SPECT). The technical feasibility of SDI was evaluated by a series of anthropomorphic phantom studies on a standard SPECT camera. The attenuation map was created by a moving transmission line source. Iterative reconstruction including attenuation correction, resolution recovery and Monte Carlo simulation of scatter was used for simultaneous reconstruction of dual tracer distribution. For clinical evaluation, patient studies were compared to stress {sup 99m}Tc and rest {sup 99m}Tc reference images acquired in a 2-day protocol. Clinical follow-up examinations like coronary angiography (CAG) and fractional flow reserve (FFR) were included in the assessment if available. Phantom studies demonstrated the technical feasibility of SDI. Artificial lesions inserted in the phantom mimicking ischaemia could be clearly identified. In 51/53 patients, the image quality was adequate for clinical evaluation. For the remaining two obese patients with body mass index > 32 the injected {sup 201}Tl dose of 74 MBq was insufficient for clinical assessment. In answer to this the {sup 201}Tl dose was adapted for obese patients in the rest of the study. In 31 patients, SDI and {sup 99m}Tc reference images resulted in equivalent clinical assessment. Significant differences were found in 20 patients. In 18 of these 20 patients additional examinations were available. In 15 patients the diagnosis based on the SDI images was confirmed by the results of CAG or FFR. In these patients the SDI images were more accurate than the {sup 99m}Tc reference study. In three patients minor ischaemic lesions were detected by SDI but were not confirmed by CAG. In one of these cases this was probably caused by pronounced apical thinning. For two patients no relevant clinical follow-up information was available for evaluation. The proposed SDI protocol has the potential to improve clinical workflow and patient comfort and suggests improved accuracy as demonstrated in the clinical feasibility study. (orig.)

Dey, Thomas [RWTH Aachen University, Institute of Imaging and Computer Vision, Aachen (Germany); Backus, Barbra E.; Romijn, R.Leo [St. Antonius Hospital, Department of Nuclear Medicine, Nieuwegein (Netherlands); Wieczorek, Herfried [Philips Research, Eindhoven (Netherlands); Verzijlbergen, J.F. [St. Antonius Hospital, Department of Nuclear Medicine, Nieuwegein (Netherlands); Erasmus Medical Center, Department of Nuclear Medicine, Rotterdam (Netherlands)

2014-03-15

71

Retrospective analysis of 201-Tl stress perfusion myocardial scintigraphy on the basis of coronarographically proved cases  

International Nuclear Information System (INIS)

The clinical effectiveness of 201-Tl stress scintigraphy for the detection of transitory ischaemic perfusion defects was examined on the basis of data from 136 patients checked by coronary angiography. The sensitivity of scintigraphy was found to be 80 per cent and specificity 66 per cent. The relatively low specificity may be partially due to the low number of true negative patients. However, non-coronary heart disease, anomalous coronary anatomy or acute coronary spasmus may also lower the specificity. Based on the results 201-Tl stress scintigraphy is recommended for the identification of coronary heart diseases of mean probability, for check up the efficiency of aorto-coronary bypass operations and for the assessment of haemodynamic consequencies of known coronary narrowings. (author)

72

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

Energy Technology Data Exchange (ETDEWEB)

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

73

Serial change of 123I-BMIPP SPECT imaging during recovery from stunned myocardium after acute myocardial infarction. Correlation with 201Tl and two-dimensional echocardiography  

International Nuclear Information System (INIS)

Using 123I-?-methyl iodophenyl pentadecanoic acid (123I-BMIPP), we investigated changes in myocardial fatty acid metabolism at recovery from stunned myocardium after acute myocardial infarction (AMI), correlation with recovery of regional wall motion and thallium-201 (201Tl) distribution in particular. The subjects were 15 patients who underwent successful reperfusion therapy after the first onset of AMI. None of the patients had multi-vessel disease or ischemic episode during their clinical course. Patients underwent 123I-BMIPP scintigraphy, 201Tl scintigraphy and two-dimensional echocardiography during the acute and chronic phases. Then, we compared regional wall motion with distribution of 123I-BMIPP and 201Tl. Regional wall motion and SPECT were evaluated by the established 16 segment model. In patients, showing serial improvement in regional wall motion, there was 80.0% (8/10) showed normal 201Tl distribution during the acute phase or normalized during the chronic phase. However, distribution of 123I-BMIPP normalized only in 10.0% (1/10) of this group. In examination of each segment that showed serial improvement in regional wall motion, 92.3% (24/26) of these segments showed normal distribution of 201Tl during the acute phase or normalized distribution during chronic phase, despite distribution of 123I-BMIPP improved in only 3.8% (1/26) of th-BMIPP improved in only 3.8% (1/26) of these segments. These indicate that, in the process of recovery from myocardial stunning after AMI, abnormal distribution of 123I-BMIPP continued longer than abnormal distribution of 201Tl. (author)

74

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

75

Assessment of myocardial viability by exercise stress myocardial tomography with 201Tl  

International Nuclear Information System (INIS)

Exercise stress (Ex) and redistribution (RD) myocardial tomography with Tl-201 has been widely used for evaluating myocardial viability. But recent studies have demonstrated that reinjection (ReI) study following RD study is necessary for detecting reversible ischemic myocardium. On the other hand, decreased myocardial washout of Tl-201 after Ex is an indicator of myocardial ischemia. So we have studied the usefulness of myocardial Tl-201 washout rate (WOR) for the evaluation of myocardial viability by comparing it with ReI images. Ex and RD myocardial tomographies were obtained immediately after Ex and 3 hours later. After RD study a small amount of Tl-201 was injected and ReI imaging was repeated. We studied 64 myocardial segments (in 58 patients with coronary artery disease) in which Ex-induced perfusion defects persisted in RD images. According to the changes of perfusion defects between Ex, RD and ReI images, they were classified into 3 types: Type I; perfusion defect on the RD image was identical to ReI image (75%). Type I was divided into 2 subgroups whether perfusion defect at Ex was unchanged (Ia, 42%) or improved (Ib, 33%) on the RD image. Type II; perfusion defect at Ex was reduced on the RD image and it improved furthermore at ReI image (17%). Type III; perfusion defect was the same at Ex and RD but it was reduced on the ReI image (8%). WOR less than 30% was defined as abnormal when Ex heart rate exceeded 120 bpm and lung-myocardial Tl-201 uptake ratio wasnd lung-myocardial Tl-201 uptake ratio was less than 0.45. The differentiation between Type Ia and Type III is of great importance. History of myocardial infarction, effort angina and Ex induced ST depression could not differentiate these 2 groups. WOR abnormality was observed in all of Type III, but WOR was normal in Type Ia. In conclusion, WOR abnormality in Ex-RD myocardial imaging is useful for evaluating myocardial viability. ReI imaging is necessary for the precise evaluation of viable muscle mass and for inadequate Ex. (author)

76

[The 4 hr-washout-functional picture: a quantitative visualization of 201Tl myocardial stress kinetics and the significance of paradoxical redistribution].  

Science.gov (United States)

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 myocardial ischemia occurring in 3-vessel disease could be recognized in the 4 h-washout functional images. PMID:4094899

Heinemann, H; Stritzke, P; Spielmann, R P; Schofer, J; Montz, R

1985-12-01

77

{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

78

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.)

79

[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

80

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)

81

Stress-induced myocardial ischemia is associated with early post-stress left ventricular mechanical dyssynchrony as assessed by phase analysis of 201Tl gated SPECT myocardial perfusion imaging  

International Nuclear Information System (INIS)

In 201Tl SPECT myocardial perfusion imaging (MPI) data are acquired shortly after the stress injection to assess early post-stress left ventricle (LV) function. The purpose of this study was to use 201Tl SPECT MPI to investigate whether stress-induced myocardial ischemia is associated with LV mechanical dyssynchrony. Enrolled in the study were 75 patients who were referred for dipyridamole stress and rest 201Tl gated SPECT MPI. The early post-stress scan was started 5 min after injection, and followed by the rest scan 4 h later. The patients were divided into three groups: ischemia group (N = 25, summed stress score, SSS, ?5, summed rest score, SRS, 201Tl gated SPECT MPI. (orig.)

82

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

83

Septal Q wave disappearance in V6 lead and myocardial damage comparison of 12-lead electrocardiography and 201Tl myocardial SPECT  

International Nuclear Information System (INIS)

Septal Q wave disappearance in V6 has been thought to signify myocardial septal damage. In this study, to verify significance of septal Q wave disappearance in V6 in cases with anteroseptal myocardial damage, we compared ECG and 201Tl SPECT findings. The subject were 107 patients (80 males, 27 females, mean age 58.2±10.1 years) who took exercise 201Tl SPECT because of suspicious of ischemic heart disease. The patients were divided into two groups. One was the patients with septal Q (septal Q (+) group) and the other was the patients without septal Q (septal Q (-) group). The definition of septal Q wave disappearance was that it was smaller than 0.025 mV. The patients with abnormal Q in V6 were excluded. A SPECT image was divided into 13 segments. Tl uptake scores were classified into 4 levels by visual evaluation at the each segments. Septal Q (-) group had a significantly higher rate of anteroseptal infarction than septal Q (+) group (p=0.01), and showed a significantly higher defect in anteroseptal area (p6 may be one of parameters which assume anteroseptal myocardial damage. (author)

84

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.)

85

Development and clinical application of an expert system for supporting diagnosis of 201Tl stress myocardial SPECT  

International Nuclear Information System (INIS)

A consultation expert system which supports our computer aided reporting system was developed. The system was used for the evaluation of the two dimensional polar (bull's eye) display of 201Tl myocardial SPECT. The system consists of patients management (PM) and consultation expert systems (ES). The former is connected to image processors coupled with scinticameras. The bull's eye display of myocardial SPECT is transfered from image processor to the data base of PM. When inference request is made, the feature extraction program extracts information on localization, extent and severity of focal defects comparing count-rates pixel by pixel with the reference obtained from seven normal controls. The inference engine is activated to determine presence of focal defects utilizing diagnostic rules in the knowledge base. The results are sent back to PM and reported with the probability of assurance. Fifty eight patients with old myocardial infarction (OMI), angina pectoris (AP) and other diseases as well as normal controls were included in the study. The decision for presence or absence of focal defects by ES agreed with that by nuclear physicians (NP) in 301 segments among 330 (91%) in stress images. The presence of redistribution in delayed images agreed in 43 segments among 67 (64%). Image interpretation by ES agreed well with that of NP in patients with OMI (19/20) and AP (9/11). Seven were interpreted as normal by both ES and NP. The system is useful, as it pr ES and NP. The system is useful, as it provides NP with complementary and supportive information applicable to decision making and reporting. Further clinical experiences can improve knowledge base for better ES function. (author)

86

Fatty acid metabolism in symptomatic patients with mitral valve prolapse but without coronary artery disease - comparison with 201Tl myocardial perfusion scintigraphy  

International Nuclear Information System (INIS)

Using 123I-?-heptadecanoic acid (HDA) and 201Tl, respectively, myocardial fatty acid metabolism and perfusion were studied in 51 symptomatic patients with mitral valve prolapse (MVP) as diagnosed by ventriculography, and no evidence of coronary artery disease. Twelve subjects with normal coronary arteries and normal ventriculogram served as a control group for the evaluation of elimination kinetics of HDA. In the control group, the mean elimination half-life was 26.1±3.6 min, whereas the patients with MVP had a mean value of 25.0±6.4 min. In patients with MVP, a high incidence concerning abnormalities of accumulation and/or elimination of HDA occurred, namely accumulation defects in 31% and both prolonged and shortened elimination half-lives in 16% and 29%, respectively. Myocardial perfusion scintigraphy using 201Tl showed abnormalities in 76%. Correlations were found between decreased uptake of HDA and prolonged elimination half-life as well as defects by 201Tl, presumably due to ischemia based on small-vessel disease or abnormalities of cellular metabolism. (orig.)

87

Assessment of myocardial perfusion and cardiac sympathetic nerve dysfunction in patients with sick sinus syndrome. Evaluation of coronary hemodynamics and 201TlCl/123I-MIBG myocardial SPECT  

International Nuclear Information System (INIS)

To clarify the coronary hemodynamics, myocardial perfusion and cardiac sympathetic nerve function in patients with sick sinus syndrome (SSS), we performed left coronary digital subtraction angiography (DSA) in 41 patients, exercise 201TlCl-myocardial scintigraphy (planar and SPECT) in 69 patients, and 201TlCl/123I-MIBG myocardial dual SPECT in 13 patients without significant organic coronary stenosis. Coronary artery spasm was documented on coronary angiography in 25/43 (58%) patients with SSS by ergonovine provocation test. Compared with normals, patients with SSS demonstrated prolongation of left coronary circulation time (CCT) on own heart beats and right atrial pacing. We suspected that prolonged CCT may be induced by increased peripheral coronary vascular resistance and impaired coronary micro-circulation in patients with SSS. Forty-two patients (60.9%) developed exercise-induced 201Tl-myocardial perfusion defect on SPECT images. On myocardial dual SPECT images, 11/13 (85%) patients showed localized myocardial low uptake in 123I-MIBG-SPECT images. In eight patients with normal findings on 201Tl-SPECT, six patients showed abnormality on 123I-MIBG-SPECT. We suspected that coronary vasospasm, impaired coronary micro-circulation and cardiac sympathetic nerve dysfunction are taken a part of pathophysiology in SSS (decreased ?-adrenergic receptor of peripheral coronary arteries?). (author)ripheral coronary arteries?). (author)

88

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

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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 /sup 201/Tl 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.

Mostbeck, A.; Steinbach, K.; Koehn, H.; Frohner, K.; Bialonczyk, C.; Unger, G.; Meisl, F. (Wilhelminenspital, Vienna (Austria). Nuklearmedizinisches Inst.; Ludwig Boltzmann-Institut fuer Nuklearmedizin, Vienna (Austria))

1983-01-01

89

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)

90

201Tl myocardial imaging in a cardiac rejection episode. Case report  

International Nuclear Information System (INIS)

Serial myocardial imaging using thallium Tl 207 was performed in the early follow-up of two patients with orthotopic cardiac transplantation. In one patient, non-homogeneous uptake, small defects and an irregular myocardial edge were observed during a moderately acute rejection crisis revealed by endomyocardial biopsy. The abnormal gammagraphic findings and histological changes were coincident and exhibited a parallel reversal. We emphasize the connection between these two events. The mechanisms which could explain these phenomena are discussed. (orig.)

91

A study on crosstalk correction in dual energy acquisition of 123I-MIBG and 201TlCl in myocardial SPECT  

International Nuclear Information System (INIS)

In the simultaneous dual energy acquisition, energy spectrums of two radionuclides crosstalk each other and this phenomenon is a cause of the poor quality of images. In order to obtain the image of high quality in dual energy acquisition of 123I-MIBG and 201TlCl, a crosstalk correction method was originated. The crosstalk from 201Tl to 123I window (RI) and the crosstalk from 123I to 201Tl window (R2) were determined by the cardiac phantom studies. R1 and R2 showed almost constant value throughout the myocardial wall. The crosstalk correction was performed using R1 and R2. After the crosstalk correction, the defect region placed in the cardiac phantom was detected more clearly both in visual interpretation and in quantitative analysis. The crosstalk correction method with R1 and R2 was applied to some clinical cases. By the crosstalk correction, the quality of image was improved and a false defect caused by crosstalk disappeared in a clinical case. The crosstalk correction was considered to be useful for improving the quality of image on dual energy acquisition. (author)

92

Clinical investigation of large perfusion defect cases with 201Tl exercise myocardial scintigraphy  

International Nuclear Information System (INIS)

We investigated retrospectively the clinical significance of large perfusion defect on 201Thallium myocardial scintigraphy from the records of 833 patients during the past 3 years from 1991 to 1994. The patients were divided into 3 groups according to the extent of perfusion defect; cases with normal perfusion (n=561), with small perfusion defect (n=211) and with large perfusion defect (n=61). We found that the proportions of cases with large perfusion defect was significantly larger than that of cases with small perfusion defect in myocardial disease (MD; hypertrophic cardiomyopathy, dilated cardiomyopathy, and post myocarditis combined) (P201Thallium myocardial scintigraphy and that complication of diabetes mellitus and clinical symptoms may be useful in differentiating IHD from MD. (author)

93

Quantitative analysis of exercise 201Tl myocardial emission CT in patients with coronary artery disease  

International Nuclear Information System (INIS)

The clinical usefulness of quantitative analysis of exercise thallium-201 myocardial emission computed tomography (ECT) was evaluated in coronary artery disease (CAD). The subjects consisted of 20 CAD patients and five normal controls. All CAD patients underwent coronary angiography. Tomographic thallium-201 myocardial imaging was performed with a rotating gamma camera, and long-axial and short-axial myocardial images of the left ventricle were reconstructed. The tomographic images were interpreted quantitatively using circumferential profile analysis. Based on features of regional myocardial thallium-201 kinetics, two types of abnormalities were studied: (1) diminished initial distribution (stress defect) and (2) slow washout of thallium-201, as evidenced by patients' initial thallium-201 uptake and 3-hour washout rate profiles which fell below the normal limits, respectively. Two diagnostic criteria including the stress defect and a combination of the stress defect and slow washout were used to detect coronary artery lesions of significance (>=75 % luminal narrowing). The ischemic volumes were also evaluated by quantitative analysis using thallium-201 ECT. The diagnostic accuracy of the stress defect criterion was 95 % for left anterior descending, 90 % for right, and 70 % for left circumflex coronary artery lesions. The combined criteria of the stress defect and slow washout increased detection sensitivity with a moderate loss of specificity for identifying individoss of specificity for identifying individual coronary artery lesion. A relatively high diagnostic accuracy was obtained using the stress defect criterion for multiple vessel disease (75 %). Ischemic myocardial volume was significantly larger in triple vessel than in single vessel disease (p < 0.05) using the combined criteria. It was concluded that quantitative analysis of exercise thallium-201 myocardial ECT images proves useful for evaluating coronary artery lesions. (author)

94

The evaluation of left ventricular eccentric hypertrophy by 201Tl-myocardial scintigraphy  

International Nuclear Information System (INIS)

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. (author)

95

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  

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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 {sup 201}Tl single-photon emission tomography (SPET) imaging for the diagnosis and localization of CAD late after acute myocardial infarction. Dobutamine (up to 40 {mu}g kg{sup -1} min{sup -1})-atropine (up to 1 mg) stress echocardiography in conjunction with stress-reinjection {sup 201}Tl 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 {sup 201}Tl 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 {sup 201}Tl SPET were 75% (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 {sup 201}Tl 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 {sup 201}Tl 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.) With 3 figs., 32 refs.

Elhendy, A.; Bax, J.J.; Domburg, R.T. van; Cornel, J.H.; Roelandt, J.R.T.C. [Thoraxcenter, Univ. Hospital Rotterdam-Dijkzigt, Rotterdam (Netherlands); Valkema, R.; Reijs, A.E.M.; Krenning, E.P. [Dept. of Nuclear Medicine, University Hospital Rotterdam-Dijkzigt, Rotterdam (Netherlands)

1999-05-01

96

Usefulness of 201Tl myocardial scintigraphy after dipyridamole infusion in patients with atherosclerotic vascular disease  

International Nuclear Information System (INIS)

To determine the utility for detecting ischemic heart disease (IHD), dipyridamole thallium myocardial images (DIP-Tl) have been performed in 103 patients with atherosclerotic vascular disease who can't exercise fully. Of the 103 patients, there were 36 patients with arteriosclerosis obliterans (ASO), 31 patients with aneurysm of the abdominal aorta (AAA), 24 patients with aneurysm of the thoracic aorta (TAA) and 12 patients with dissecting aortic aneurysm (DAA). Clinical evidence of IHD was found in 20 patients with ASO, 10 with AAA, 7 with TAA and 4 with DAA. Positive evidence of DIP-Tl was identified in 66% of 41 patients who had clinical evidence of IHD, and particularly in the patients with AAA (80%) and ASO (65%). On the other hand, in the patients without clinical evidence of IHD, positive evidence of DIP-Tl was identified in 19% of 62 patients and particularly in the patients with AAA (39%). In all patients, the percentage of the positive DIP-Tl ratio was 38%. And, when the 38% patients of the positive DIP-Tl were added to the patients of the negative DIP-Tl who had clinical evidence of IHD, almost half patients (51%) were considered to be complicated with IHD. This study suggests that the atherosclerotic vascular disease is highly complicated with IHD and DIP-Tl is useful to detect IHD. (author)

97

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)

98

Impaired coronary flow reserve is the most important marker of viable myocardium in the myocardial segment-based analysis of dual-isotope gated myocardial perfusion single-photon emission computed tomography  

International Nuclear Information System (INIS)

The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), 201Tl perfusion status at rest, 201Tl 24 hours redistribution and systolic wall thickening of 99mTc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery. A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 ± 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG. The left ventricular ejection fraction (LVEF) significantly increased from 37.8 ± 9.0% to 45.5 ± 12.3% (p 201Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001). Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG.

99

Dual myocardial scintigraphic imaging using 123I-BMIPP and 201Tl in patients with Duchenne's progressive muscular dystrophy  

International Nuclear Information System (INIS)

Dual single photon emission computed tomography (SPECT) was performed in 30 patients with Duchenne's muscular dystrophy (DMD) using 201 thallium (Tl) for myocardial perfusion 123I-?-methyl-p-iodophenylpentadecanoic acid (BMIPP) for myocardial fatty acid metabolism scintigraphy. The left ventricle was divided into 9 regions, and accumulation of the radiotracers was assessed visually for each region to calculate defect score for each tracer. There was some degree of decrease in the myocardial accumulation of both tracers in all DMD patients. Reduced accumulation was most common at the apex (BMIPP, 70%; Tl, 63%), followed by the posterior wall, lateral wall, and anterior wall. It was less common on the apical side of the ventricular septum for both tracers (BMIPP, 3%; Tl, 17%). Accumulation of Tl was lower than BMIPP in 18/30 patients (60%) and higher in 9 (30%), while both tracers showed equal accumulation in 3 (10%). BMIPP showed higher accumulation than Tl in all regions but the septum. A significant negative correlation was found between the defect scores for both tracers and the left ventricular ejection fraction (LVEF) (r=-0.629 for Tl; r=-0.567 for BMIPP). The strongest negative correlation was that between the sum of the Tl and BMIPP defect scores and the LVEF (r=-0.681). Dual SPECT myocardial scintigraphy with Tl and BMIPP provided an accurate evaluation of the progression of cardiac lesions in DMD by detecting abnormalities of the myocardby detecting abnormalities of the myocardial metabolism of each substance thereby enabling the assessment of left ventricular function. (author)

100

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)

101

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

Energy Technology Data Exchange (ETDEWEB)

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

102

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.)

103

Stress-induced myocardial ischemia is associated with early post-stress left ventricular mechanical dyssynchrony as assessed by phase analysis of {sup 201}Tl gated SPECT myocardial perfusion imaging  

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In {sup 201}Tl SPECT myocardial perfusion imaging (MPI) data are acquired shortly after the stress injection to assess early post-stress left ventricle (LV) function. The purpose of this study was to use {sup 201}Tl SPECT MPI to investigate whether stress-induced myocardial ischemia is associated with LV mechanical dyssynchrony. Enrolled in the study were 75 patients who were referred for dipyridamole stress and rest {sup 201}Tl gated SPECT MPI. The early post-stress scan was started 5 min after injection, and followed by the rest scan 4 h later. The patients were divided into three groups: ischemia group (N = 25, summed stress score, SSS, {>=}5, summed rest score, SRS, <5), infarct group (N = 16, SSS {>=}5, SRS {>=}5) and normal group (N = 34, SSS <5, SRS <5). LV dyssynchrony parameters were calculated by phase analysis, and compared between the stress and rest images. In the ischemia group, LV dyssynchrony was significantly larger during stress than during rest. On the contrary, LV dyssynchrony during stress was significantly smaller than during rest in the normal and infarct groups. LV dyssynchrony during rest was significantly larger in the infarct group than in the normal and ischemia groups. There were no significant differences in LV dyssynchrony during rest between the normal and ischemia groups. Stress-induced myocardial ischemia caused dyssynchronous contraction in the ischemic region, leading to a deterioration in LV synchrony. Normal myocardium had more synchronous contraction during stress. The different dyssynchrony pattern between ischemic and normal myocardium early post-stress may aid the diagnosis of coronary artery disease using {sup 201}Tl gated SPECT MPI. (orig.)

Chen, Chien-Cheng; Shen, Thau-Yun [Show Chwan Memorial Hospital, Department of Cardiology, Changhua (China); Chang, Ming-Che [Changhua Christian Hospital, Department of Nuclear Medicine, Changhua (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China); Chen, Wan-Chen [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); Kao, Chia-Hung [China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China); Chen, Ji [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States)

2012-12-15

104

Comparison between 123I-BMIPP and 201TlCl myocardial imaging by circumferential profile analysis in patients with myocardial infarction. Evaluation of effects of vascular reconstruction in patients with myocardial infarction  

International Nuclear Information System (INIS)

We quantitatively evaluated the effects of vascular reconstruction according to the stage by 123I-BMIPP and 201TlCl using circumferential profile (CP) curve method in patients with myocardial infarction. Comparison of the CP curves for the two nuclides in normal volunteers (n=9) showed no difference in distribution. In patients with myocardial infarction (n=32) the severity score was evaluated using the CP curves obtained in the normal volunteers. Type B (marked decrease in 123I-BMIPP accumulation) accounted for 83% in the group in whom vascular reconstruction was performed in the acute stage (Group I) and 91% in the group in whom vascular reconstruction was performed in the chronic stage (Group II). On the other hand, type E (similar accumulation between the two nuclides) accounted for 79% in the group in whom vascular reconstruction was unsuccessful or was not performed (Group III). The severity score for each nuclide did not significantly differ among Groups I, II and III. The 123I-BMIPP/201TlCl ratio was the highest in Group II, followed in order by Group I and Group III (p<0.05). The assessment of the ratio of 'severity scores' for both nuclides is considered to be useful for evaluation of the surviving myocardium, rather than the assessment of a single nuclide. (author)

105

Effects of ischemia-reperfusion injury on myocardial single pass extraction and retention of Cu-PTSM in perfused rat hearts: comparison with 201Tl and 14C-iodoantipyrine  

International Nuclear Information System (INIS)

The effects of ischemia-reperfusion-induced myocardial damage on the single pass extraction and retention of 64Cu-pyruvaldehyde-di-(N4-methylthiosemicarbazone) (64Cu-PTSM) in perfused rat hearts were compared to these effects on that of 201Tl and 14C-iodoantipyrine. 201Tl and 14C-iodoantipyrine did not show significant changes, but in the case of 64Cu-PTSM, the single pass extraction and retention was reduced with reperfusion. These findings indicate that ischemia-reperfusion-induced myocardial damage decrease the generator-produced 62Cu-labeled 62Cu-PTSM extraction and retention, and that 62Cu-PTSM might have potential not only as a blood flow tracer but also as a functional tracer. (author)

106

Effects of ischemia-reperfusion injury on myocardial single pass extraction and retention of Cu-PTSM in perfused rat hearts: comparison with [sup 201]Tl and [sup 14]C-iodoantipyrine  

Energy Technology Data Exchange (ETDEWEB)

The effects of ischemia-reperfusion-induced myocardial damage on the single pass extraction and retention of [sup 64]Cu-pyruvaldehyde-di-(N[sup 4]-methylthiosemicarbazone) ([sup 64]Cu-PTSM) in perfused rat hearts were compared to these effects on that of [sup 201]Tl and [sup 14]C-iodoantipyrine. [sup 201]Tl and [sup 14]C-iodoantipyrine did not show significant changes, but in the case of [sup 64]Cu-PTSM, the single pass extraction and retention was reduced with reperfusion. These findings indicate that ischemia-reperfusion-induced myocardial damage decrease the generator-produced [sup 62]Cu-labeled [sup 62]Cu-PTSM extraction and retention, and that [sup 62]Cu-PTSM might have potential not only as a blood flow tracer but also as a functional tracer. (author).

Wada, Kouichi; Fujibayashi, Yasuhisa; Taniuchi, Hideyuki; Tajima, Naoyuki; Yokoyama, Akira (Kyoto Univ. (Japan). Faculty of Pharmaceutical Sciences); Tamaki, Nagara; Konishi, Junji (Kyoto Univ. (Japan). School of Medicine)

1994-05-01

107

The significance of [sup 201]Tl/[sup 123]I MIBG (metaiodobenzylguanidine) mismatched myocardial regions for predicting ventricular tachycardia in patients with idiopathic dilated cardiomyopathy  

Energy Technology Data Exchange (ETDEWEB)

[sup 123]I-MIBG (MIBG) regional defects in myocardial regions with preserved [sup 201]Tl (Tl) uptake have been observed in patients with idiopathic dilated cardiomyopathy (DCM). To evaluate whether the presence of Tl/MIBG mismatched regions is related to the occurrence of ventricular tachycardia (VT), we performed myocardial dual SPECT imaging with Tl (111 MBq) and MIBG (111 MBq) in 17 patients with DCM, 11 (Gp A) with and 6 (Gp B) without VT. Myocardial dual SPECT imaging was performed at 15 minutes after and 4 hours after the tracer injection. The regional tracer uptake was scored visually in 6 segments of the basal, middle, and apical short-axial images and in 2 apical segments of the midventricular vertical long-axial image by a four-point scoring system (0=normal, 1=moderate, 2=severe and 3=complete defect). Then, the severity of tracer maldistributions was assessed by the difference between total defect scores (TDSs) of Tl and MIBG ([Delta]TDS). TDS was not different between Gps A and B in both Tl and MIBG images. However, [Delta]TDS was larger in Gp A than in Gp B (13.5[+-]6.5 vs. 5.8[+-]3.0, p<0.05). Also, the number of segments with the mismatched tracer uptake was larger in Gp A than in Gp B (12.5[+-]3.0 vs. 8.3[+-]1.5, p<0.01). In the electrophysiologic study, we found that the fractionated area corresponded to the mismatched region in 3 of 5 patients in Gp A. These results suggest that regional sympathetic denervation is a possible factor which provocates VT, and myocardial dual SPECT imaging with Tl and MIBG is a useful method for predicting VT in patients with DCM. (author).

Maeno, Masakazu; Ishida, Yoshio; Shimonagata, Tsuyoshi (National Cardiovascular Center, Suita, Osaka (Japan)) (and others)

1993-10-01

108

Impaired coronary flow reserve is the most important marker of viable myocardium in the myocardial segment-based analysis of dual-isotope gated myocardial perfusion single-photon emission computed tomography  

Energy Technology Data Exchange (ETDEWEB)

The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), {sup 201}Tl perfusion status at rest, {sup 201}Tl 24 hours redistribution and systolic wall thickening of {sup 99m}Tc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery. A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 ± 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG. The left ventricular ejection fraction (LVEF) significantly increased from 37.8 ± 9.0% to 45.5 ± 12.3% (p < 0.001) in 22 patients who had a pre-CABG LVEF lower than 50%. Among 590 myocardial segments in the re-vascularized area, 115 showed abnormal wall motion before CABG and 73.9% (85 of 115) had wall motion improvement after CABG. In the univariate analysis (n = 115 segments), stress/rest reversibility (p < 0.001) and {sup 201}Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001). Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG.

Lee, Won Woo [Dept. of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); So, Young [Dept. of Nuclear Medicine, Konkuk University School of Medicine, Seoul (Korea, Republic of); Kim, Ki Bong; Lee, Dong Soo [Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2014-04-15

109

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)

110

Quantitative analysis of acute myocardial infarction using single photon emission computed tomography using technetium-99m pyrophosphate  

International Nuclear Information System (INIS)

The usefulness of single photon emission computed tomography (SPECT) using technetium-99m pyrophosphate (99mTc-PPi) was evaluated in 15 patients with acute myocardial infarction. SPECT was performed with a rotating gamma camera after conventional planar images were made. Infarct size was measured from transaxial images of myocardial pyrophosphate uptakes. In each slice, the boundary was defined by subtracting 70 percent of the maximal counts and the number of voxels automatically counted. This subtraction rate was determined by phantom study and by compraing SPECT using 99mTc-PPi with thallium-201-gated myocardial scintigraphy (201Tl gated SPECT). The planar images showed diffuse uptakes in two of the 15 patients, and in these cases it was difficult to detect the infarct site. In contrast, SPECT images clearly imaged the infarct site consistent with the electrocardiographic findings, and they were definitely separated from the uptakes in the bones in all cases. Infarct size, ranging from 3.4 ml to 78.3 ml, correlated well with cumulative creatine kinase release (r = 0.84, p 99mTc-PPi is a useful means of investigating the spatial distribution of pyrophosphate uptake and of evaluating the size of myocardial infarction. (author)nfarction. (author)

111

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

112

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.)

113

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)

114

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

115

Incremental prognostic value of myocardial SPET with dual-isotope rest 201Tl/stress 99mTc-tetrofosmin  

International Nuclear Information System (INIS)

The incremental prognostic value of dual-isotope myocardial perfusion scintigraphy using technetium-99m tetrofosmin for the stress images was evaluated in 597 consecutive patients with known or suspected coronary artery disease. We used semi-quantitative visual analysis with a five-point scoring system and calculated the summed stress score, the summed rest score and the summed difference score. During the 2-year follow-up period, 46 ''hard'' cardiac events occurred: 16 cardiac deaths and 30 non-fatal myocardial infarctions. Kaplan-Meier analysis demonstrated a favourable prognosis for patients with normal scans as compared with patients with mildly to moderately or severely abnormal scans (P<0.001). Multivariate analysis demonstrated incremental prognostic information for nuclear variables. A very low rate of hard cardiac events was observed in patients with a low summed stress score. Thus, nuclear variables provide incremental prognostic information and could be used to guide the management process with respect to whether or not to proceed with further invasive procedures. (orig.)

116

The white-hole phenomenon - a potential parameter of function in non-gated 201Tl myocardial scintigraphy  

International Nuclear Information System (INIS)

In 50 patients with a ''white hole'' in their scintigram - among them 44 patients with a history of myocardial infarction - the relation between its relative volume and the ventriculographically determined ejection fraction was studied retrospectively. A relative volume of the ''white hole'' larger than 13.7% showed a specificity of 93% and a sensitivity of 45% for a decreased ejection fraction and had a significant correlation of r=-0.54 (alpha=0.01) with the ejection fraction. Thus the relative volume of the ''white hole'' derived automatically from 221TI-SPECT is an easy-to-determine additional parameter which allows an at least semiquantitative statement about the function of the left ventricle. (orig.)

117

The quantification of Tl and Cu concentrations in 201Tl solutions using anodic stripping voltammetry  

International Nuclear Information System (INIS)

Thallium-201 is a cyclotron produced isotope which is used in nuclear medicine for myocardial function studies. Thallium-201 is prepared by the (p, 3n) reaction on 203Tl to form 201PB which decays by positron emission to 201Tl. Prior to irradiation the thallium target is electro-deposited onto a copper cathode. After irradiation the target is processed by leaching the cathode with dilute acid and passing the leachate through ion exchange resins. Pharmocopoeia monographs on pharmaceutical grade 201Tl define limits on the concentrations of Tl and Cu which may be present in solutions of 201Tl. It is therefore important from a quality control viewpoint to have a rapid, accurate means of analysis to quantify levels of these metals in radioactive solutions of 201Tl. We have developed a procedure utilizing anodic stripping voltammetry to quantify concentrations of Tl and Cu in solutions of 201Tl. (author)

118

Thymic scintigraphy using 201Tl-chloride  

International Nuclear Information System (INIS)

Thymic scintigraphy using Thallium-201 Chloride (201TlCl) was performed on 3 cases of thymoma (2 malignant mediastinal thymomas and 1 benign cervical thymoma). All of the 3 cases exhibited high abnormal activities corresponding to the tumor on the scintigram. Thus it is useful to perform the scintigraphy using 201TlCl for the detection of thymoma. (author)

119

Spectroscopy of 201Tl isotope  

International Nuclear Information System (INIS)

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

120

Distribution of 201Tl in the blood  

International Nuclear Information System (INIS)

Thallium-201 distribution in the blood was investigated both in vivo and in vitro. Thallium-201 was distributed into the erythrocytes and plasma with the ratio of 1.4 +- 0.3 to 1.0, immediately after its administration. The uptake of 201Tl into the erythrocytes in vitro were affected by the incubation temperature and the presence of ouabain and KCl; indicating that the 201Tl was uptaken into cells partly through their membranes Na, K-ATPase. Erythrocytes could retain 201Tl in it, whereas 201Tl was present as free ion in the plasma. Thallium-201 was flew out of erythrocytes into the plasma, keeping the ratio of 201Tl in erythrocytes/plasma to be 1.9 +- 0.2/1.0. (author)

121

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

International Nuclear Information System (INIS)

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.)

122

Clinical value of iodine-123 beta-methyliodophenyl pentadecanoic acid (BMIPP) myocardial single photon emission computed tomography for predicting cardiac death among patients with chronic heart failure  

International Nuclear Information System (INIS)

In the present study, the effectiveness of 123I-?-methyliodophenyl pentadecanoic acid (BMIPP) single photon emission computed tomography (SPECT) for predicting cardiac death of patients with chronic heart failure was evaluated. Abnormalities of fatty acid metabolism are found in patients with chronic heart failure and BMIPP was developed as a tracer for scintigraphic assessment of myocardial fatty acid utilization. The study group comprised 74 patients with chronic heart failure with a left ventricular ejection fraction (LVEF) 201Tl SPECT and BMIPP SPECT. The uptake of tracer was scored semiquantitatively from 0 (normal) to 4 (defect) in 20 segments and a total defect score (TDS) for all 20 segments was calculated. On planar images the mediastinum to heart count ratio (H/M) was calculated for the BMIPP and Tl studies, and the H/MBMIPP:H/MTl (H/MBMIPP divided by H/MTl) was also calculated. The mean follow-up period was 660 days and there were 17 cases of cardiac death. Multivariate analysis identified H/MBMIPP:H/MTl (pBMIPP:H/MTl was situated to the left relative to LVEF. Analysis of the myocardial metabolism by BMIPP SPECT can predict the high-risk patients wPECT can predict the high-risk patients with chronic heart failure. (author)

123

Myocardial perfusion imaging with sup 99m Tc-methoxy isobutyl isonitrile and SPECT for patients with clinically suspected ischemic heart disease; Comparison with sup 201 Tl-SPECT  

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The usefulness of a new myocardial perfusion agent, {sup 99m}Tc-MIBI, was investigated in 10 patients with clinically suspected ischemic heart disease by comparison with {sup 201}Tl-SPECT. The MIBI images were clearer than those of Tl in 8 cases and both images were almost the same quality in 2 cases. Liver uptake overlapped on the inferior and posterior walls in only one case at the early (30 min) rest image but it was disappeared at the late (4 h) image. Newly appeared perfusion defect in 4 examinations at the late (4 h) image in spite of no defect at the early (30 min) image indicated that washing out of MIBI also could not be ignored in some cases. All MIBI exercise images were coincident with Tl exercise early images. All MIBI rest images expect for 2 examinations were coincident with Tl delayed images. Although more investigations are necessary for washing out from the myocardium and the difference with Tl findings, we concluded that {sup 99m}Tc-MIBI was a promising radiopharmaceutical for myocardial perfusion imaging. (author).

Otsuka, Makoto; Ichiya, Yuichi; Kuwabara, Yasuo; Sasaki, Masayuki; Fukumura, Toshimitsu; Masuda, Kouji; Makizumi, Kazuhiro; Tsuda, Yasuo (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

1991-09-01

124

/sup 201/Tl heart studies  

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At the annual meeting of the Society of Nuclear Medicine there was a preponderance of papers dealing with the heart. The most impressive papers detailed the use of monovalent cation /sup 201/Tl in the evaluation of coronary artery disease. Thallium-201 behaves like potassium in that it enters heart muscle quickly and persists in that organ for several hours. It is unlike most radioactive potassium analogues used for heart studies in that: (1) its gamma energy peaks (69 keV and 80 keV) are more easily collimated with resultant image improvement, (2) its physical half life of 72 hours is sufficiently short to attain high counting rates without too much radiation and is sufficiently long so that storage is not prohibitive, (3) its short half life and lack of Beta radiation results in lower radiation to the patient, and (4) its uptake in heart is greater and uptake in liver and stomach less than other potassium analogues.

Bell, R.L.

1976-09-01

125

Thallium-201 single photon emission computed tomography (SPECT) in patients with Duchenne's progressive muscular dystrophy. A histopathologic correlation study  

International Nuclear Information System (INIS)

The pathomorphologic mechanism responsible for abnormal perfusion imaging during thallium-201 myocardial single photon emission computed tomography (201Tl-SPECT) in patients with Duchenne's progressive muscular dystrophy (DMD) was investigated. Hearts from 7 patients with DMD were evaluated histopathologically at autopsy and the results correlated with findings on initial and delayed resting 201Tl-SPECT images. The location of segments with perfusion defects correlated with the histopathologically abnormal segments in the hearts. Both the extent and degree of myocardial fibrosis were severe, especially in the posterolateral segment of the left ventricle. Severe transmural fibrosis and severe fatty infiltration were common in segments with perfusion defects. In areas of redistribution, the degree of fibrosis appeared to be greater than in areas of normal perfusion; and intermuscular edema was prominent. Thus, the degree and extent of perfusion defects detected by 201Tl-SPECT were compatible with the histopathology. The presence of the redistribution phenomenon may indicate ongoing fibrosis. Initial and delayed resting 201Tl-SPECT images can predict the site and progress of myocardial degeneration in patients with DMD. (author)

126

Identification of myocardial viability by exercise/reinjection myocardial single photon emission computed tomography  

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The present study explored the value and limitation of exercise/reinjection myocardial single photon emission computed tomography (SPECT) for assessing myocardial viability in 6 patients with angina pectoris (AP), 19 with acute myocardial infarction (AMI), and 6 with old myocardial infarction (OMI) associated with AP. Exercise (E) early and delayed images were acquired after iv injection of Tl-201 (111 MBq), and the subsequent reinjection (REINJ) images were acquired 15 min after iv reinjection of Tl-201 (37 MBq). Within one week after REINJ scanning, rest (R) early and delayed myocardial SPECT scannings were performed for comparison. E-early, E-delayed, REINJ, R-early, and R-delayed images were quantitatively evaluated by using visual interpretation and Bull's eye display. Visual interpretation of perfusion defects in 20 segments of the myocardium was scored on a 0-4 scale. In Bull's eye display, extent score (ES) and severity score (SS) were calculated from mean±2 SD obtained from normal volunteers; and the degree of improvement for ischemia was expressed as %ES and %SS by dividing each score on E-delayed, REINJ, R-early, and R-delayed images by each of them on E-early images. The group of AMI patients had significantly increased redistribution on REINJ, R-early, and R-delayed images, as compared with the other two groups. Similarly, in this group, both %ES and %SS were significantly improved on these images, as compared with the E-delayed image. The other groups oh the E-delayed image. The other groups of AP and OMI patients had, however, no significant changes in either %ES or %SS on the E-early, E-delayed, REINJ, R-early, and R-delayed images. Since the solitary use of exercise scanning underestimated myocardial viability in the case of AMI, an additional REINJ scanning may be used in place of rest scanning in terms of its simplicity. (N.K.)

127

Exercise myocardial perfusion scintigraphy is useful for evaluating myocardial ischemia even in the elderly  

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Pharmacologic stress testing is recommended to elderly patients as a valuable alternative to exercise testing. We examined whether exercise testing is as useful for evaluating myocardial ischemia in the elderly as in the young. The consecutive 1,508 patients who underwent exercise 201Tl single-photon emission computed tomography (SPECT) were divided into six age groups: 6-29 years (n=56), 30-44 (n=143), 45-54 (n=311), 55-64 (n=498), 65-74 (n=402), and 75-88 (n=98). Both heart rate and rate-pressure product at peak exercise were significantly lower in patients aged 75-88 than in the other five groups. The frequency of ischemic ST depression was higher in patients aged 75-88 than in those aged 6-74, although the difference was not significant. Moreover, the frequency of 201Tl transient defect was significantly higher in patients aged 75-88 than in those aged 6-74. On the other hand, the sensitivity of ischemic ST depression for 201Tl transient defect was similar among the six groups, but the specificity was significantly lower in patients aged 75-88 than in those aged 6-74. In conclusion, exercise 201Tl SPECT is useful for evaluating myocardial ischemia even in the elderly, but exercise electrocardiography has limitations such as lower specificity in the elderly than 201Tl SPECT. (author)

128

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)

129

Quantification of the extent and severity of myocardial ischemia in single-vessel disease using stress-redistribution thallium-201 single-photon emission computerized tomography  

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Single-vessel coronary artery (CA) disease (SVD) is not uniformly benign: long-term prognosis is likely to be related to the extent (E) and severity (S) of myocardial ischemia (isch). To assess the ability of stress thalium-201 (Tl) single photon emission computerized tomography (SPECT) to quantify E and S of isch, the authors studied 15 patients (pts) without myocardial infarction who had SVD (8 LAD, 4 RCA, and 3 LCX). SPECT cuts were analyzed using maximum count circumferential profiles (CPs) which were compared with previously established normal (nl) limits derived from 20 nl pts. E of isch was defined as the % of the CP points falling below nl, S and depth (D) of ischemia respectively expressed the total and the mean % by which the abnormal points fell below normal limits. Although all pts had SVD, the range of E, S and D of isch was wide (0 to 48% and 0 to 38% and 0 to 20% respectively). CA scores (CS) were derived using a 15-point system accounting for the distribution of the diseased CA, location, and degree of stenosis, and collateral supply. CS varied from 1.2 to 8. E and S significantly correlated with CS (r=.74,p=.001, and r=.78, p=.000, respectively). The 6 pts with a D ? .1 had 75% CA stenosis whereas 5 of the 9 pts with D <.1 had only 50-75% stenosis. Thus, the authors conclude that: 1) pts with SVD have highly differing degrees of isch; 2) E, S and D scores from Tl SPECT correlate favorably with the angiographic extent and severity of disease; and 3) SPECT offers potential for quantification of the magnitude of isch and may become a useful, noninvasive prognostic indicator

130

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

131

Evaluation of the ischemic myocardium in acute coronary syndromes using 123I-MIBG and 201TlCl SPECT imaging  

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Images from myocardial I-123-meta-iodobenzylguanidine (MIBG) single photon emission computed tomography (SPECT) and Tl-201 SPECT were reviewed in 20 patients with acute coronary syndromes, including 6 with unstable angina and 7 with non-transmural myocardial infarction. Myocardial SPECT imaging was undertaken 90 min after iv injection of I-123 MIBG, followed by myocardial perfusion SPECT imaging 15 min after iv injection of 201TlCl. One week later, coronary arteriography was performed. Of 7 patients with non-transmural myocardial infarction, 3 were not recognized as having hypoperfusion or defect on Tl-201 images, but were found to have defects in culprit vessels on I-123 MIBG images. In 3 of 6 patients with unstable angina, I-123 MIBG imaging clearly visualized defects in culprit vessels, although there were no abnormal findings in serum creatinine kinase or Tl-201 myocardial imaging. Thus I-123 MIBG myocardial imaging was found to visualize ischemic zones, not detected by the other imaging methods, especially in non-transmural myocardial infarction and unstable angina. (N.K.)

132

201Tl-redistribution analysis in early and delayed myocordial scintigrams of patients with coronary heart disease (CHD)  

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Scans were performed on 8 healthy subjects and 25 with coronary heart disease proven by angiography and ventriculography including 6 with previous myocardial infarction at rest, exercise, and 1 and 2 h after exercise. Data were collected by a gamma camera interfaced to a data collection system. In healthy subjects 201Tl distribution was homogeneous at rest and after exercise, the count rate ranging between 100% - as set in the region of maximum - and 80% over other regions of myocardium. In 19 patients with coronary heart disease it was uniform only at rest; 6 patients with previous myocardial infarction had locally diminished 201Tl uptake even at rest. In patients with coronary heart disease without previous myocardial infarction, scans made immediately after exercise showed significant 201Tl hypofixation in region of minimum, the count rate of which was less than 80% of the count rate as determined over region of maximum, 201Tl uptake. Scans made 1 and 2 h after exercise had filling-in of 201Tl within the region of minimum the count rate of which returned to the normal range of at least 80% of the count rate measured over region of maximum uptake. This return to resting distribution was called 201Tl redistribution. Six patients with coronary heart disease and previous myocardial infarction had 201Tl defects larger after exercise than at rest, without redistribution being observed. Redistribt redistribution being observed. Redistribution in late postexercise scans is a sign of reversible ischemia in coronary heart disease. Scans at rest may be omitted in coronary heart disease, because transient ischemia is undetectable, unless spontaneous angina occurs during scan procedure. (orig.)

133

A comparison of prone SPET and left lateral (decubitus) planar imaging for inferior wall attenuation artefact in 201Tl myocardial imaging  

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Full text: Inferior wall attenuation artefacts are a major problem in supine SPET (S-S) myocardial perfusion imaging. SPET imaging with the patient lying in the prone position (P-S) and left lateral planar imaging with the patient lying in the right lateral decubitus position (LL) ameliorate this artefact. This study attempts to define the clinical role of P-S and LL imaging in characterizing S-S inferior wall defects. 21 patients with an inferior wall defect on S-S then had LL and rapid P-S imaging. All images were performed with a GE Optima NX gamma camera using GENIE acquisition and processing. All SPETs used 16 stops (32 frames) through 90 deg, with 40 s per stop for SS and 14 s per stop for P-S. LL images were acquired for 150 s. All images were assessed for adequacy and inferior wall scored for 0 = no, 1 mild, 2 moderate and 3 = severe defects. Statistical analysis was performed using the Wilcoxon rank sum test for matched pairs. All images were adequate for analysis. Significantly fewer defects were seen in P-S vs S-S, LL vs S-S (P 0.88); however; there was a difference (P < 0.05) in the subgroup (n = 7) with moderate defects on S-S imaging but no LL defect. In conclusion, most inferior wall defects seen on S-S imaging can be attributed to either attenuation or true perfusion defects with the use of LL imagingrfusion defects with the use of LL imaging. Prone imaging may only be helpful where the inferior defect is of moderate severity but no LL defect is seen

134

Comparison in regard to myocardial sympathetic denervation between {sup 123}I-MIBG and {sup 201}Tl in patients with vasospastic angina pectoris  

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Of the patients who were diagnosed as having vasospastic angina (VSA) with coronary spasm proven by acetylcholine (Ach) on coronary angiograms were used as the subjects. There were 39 males and 15 females. MIBG and Tl were administered to all of the 54 cases before coronary angiography. MIBG in a dose of 111 Mbq was injected intravenously at rest. A photograph was taken after 3 hours for a delayed image. Tl myocardial blood flow image was taken immediately after exercise loading and a redistribution image 3 hours later. Results of administration of MIBG and Tl were restudied 3 to 6 months after inception of the treatment in 14 out of 54 cases. The proportion of positive cases was significantly high with MIBG, with 52 (97%) out of 54 cases found positive with MIBG and 10 (19%) out of 54 cases with Tl (p<0.05). The number of cases which were positive with both MIBG and Tl was 10 (19%) but there was no positive case with Tl alone. 42 (78%) out of 54 cases were found positive with MIBG alone, which was significantly high compared with the Tl positive cases (P<0.01). The sensitivity of MIBG tended to be higher than that of Tl, with the sensitivity 19.6% and specificity 42.8% with Tl against the sensitivity 74.4% and specificity 36.8% with MIBG (P<0.1). A significant improvement (P<0.01) was noted with MIBG, with the defect score after treatment being -8.9{+-}6.0 against -13.5{+-}7.7 before treatment. With Tl no significant difference was found, with -5.2{+-}2.3 after treatment against -8.2{+-}4.3 before administration. In VSA, the frequency of the decline in accumulation was higher with MIBG than with Tl. MIBG is thought to sharply reflect past ischemia. With MIBG, a significant improvement in the defect score was seen before and after treatment. So MIBG considered useful for judging the therapeutic effect as well. (K.H.)

Ohta, Katsuhisa [Kanazawa Medical Univ., Uchinada (Japan)

1996-06-01

135

Background subtraction in 201Tl myocardscintigraphy  

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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.)

136

Thallium-201 myocardial single photon emission computed tomography after isoproterenol infusion in diagnosing ischemia heart disease  

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Patients with obstructive atherosclerotic disease of the peripheral arteries are often unable to undergo a standard Treadmill test for evaluation of concomitant coronary artery diseases. To establish an alternative method of testing, 27 patients had intravenous infusion of isoproterenol, up to 1.0 ..mu..g/kg, in conjugation with myocardial thallium-201 single photon emission computed tomography (SPECT). All underwent coronary angiography. Thallium-201 myocardial SPECT after isoproterenol infusion was found to have 100 % sensitivity and 100 % specificity for detecting coronary artery diseases (stenotic or occluded coronary arteries with or without myocardial infarction) and 87 % sensitivity and 100 % specificity for detecting stenotic coronary arteries with viable regional myocardium. No major complication was experienced during and after this study. It is concluded that serial thallium-201 myocardial SPECT after isoproterenol infusion is safe, reliable and useful for detecting coronary artery disease when standard exercise test is not feasible.

Aizawa, Nobuyuki; Kim, Kunikane; Hara, Yoshikuni; Shimizu, Toshio; Mitsui, Tamito; Yamazaki, Yuki; Suzuki, Yutaka.

1988-05-01

137

Quality control of 201TlCl solution obtained at IPEN-CNEN/SP  

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The radiopharmaceutical 201TlCl (thallium-201 chloride) 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 from the CV-28 cyclotron installed at IPEN-CNEN/SP. This solution was subjected to different quality control processes required for its use in medicine. Some of these controls concerned the determination of the radionuclidic impurities: 200Tl, 202Tl and 203Hg; the chemical identification of 201Tl+; the hydrazine concentration, mercury contamination and the presence of phosphate. Furthermore, the biological distribution 'in Wistar' rats and tests for sterility, pyrogenecity and toxicity were carried out. It was verified that the solution obtained was in the form of thallous chloride. This radiopharmaceutical gave good heart images in animals but due to the high levels of 200Tl and 202Tl its use in humans is not possible unless enriched 202Hg is used as target in the irradiation. (author) 6 refs.; 3 figs.; 2 tabs

138

Clinical study of sarcoidosis with special reference to significance and diagnostic value of 201Tl scintigraphy and 99mTc perfusion lung scintigraphy  

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Both 201Tl scintigraphy and 99mTc-MAA perfusion lung scintigraphy were performed in 31 patients with sarcoidosis and the perfusion lung scintigraphy only was performed in additional 11 patients. In order to evaluate the diagnostic usefullness and the significance of these methods, the scintigraphic findings were compared with other clinical findings such as chest roentgenographic findings, pathological changes on the biopsy specimen, levels of serum angiotensin converting enzyme (ACE), pulmonary function data and so on. From the present study, the results were summarized as follow : 1) Diffuse 201Tl lung uptake was observed in 23 cases (74.2 %), but its intensity was mild or moderate in most cases. 2) The intensity of 201Tl lung uptake had a tendency to be related to the quantity of abnormal lung shadows on the chest x-ray film, the frequency of epithelioid granuloma on the biopsy specimen, levels of serum ACE and serum lysozyme. However, no good relationship was obtained between the intensity of 201Tl lung uptake and pulmonary function data or the intensity of alveolitis on the biopsy specimen. 3) There was close relationship between 201Tl uptake of hilar or mediastinal lymphnodes and chest roentgenographic findings of lymphadenopathy. In mediastinal lymphnodes, however, about half of roentgenographically negative cases showed 201Tl uptake. 4) In the 201Tl myocardial image, visual 201Tl myocardial image, visualization of the right ventricle and the myocardial perfusion defect were revealed in 17 and 9 cases, respectively. 5) In the perfusion lung scintigraphy, perfusion abnormalities were observed in 41 of 42 cases. They were more frequently observed in the upper and/or middle fields and peripheral areas of the lung. (author)

139

Significance of single photon emission computed tomography with Tc-99m pyrophosphate in acute myocardial infarction  

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To examine the value of single photon emission computed tomography with Tc-99m pyrophosphate (PYP-SPECT) in delineating myocardial infarts, 38 patients with documented acute myocardial infarction were studied. Planar imaging (PI) had sufficient ability to detect transmural infarcts; and SPECT requiring much more time for examination is unlikely necessary. In contrast, PYP-SPECT significantly improved sensitivity for delineating subendocardial infarcts (SEI) compared with PI (84 % versus 46 %). Patients with diffuse accumulation of PYP on PI tended to show SEI or inferoposterior infarcts (IPI) on ECG, or merely had blood pool images. Right ventricular accumulation of PYP was visualized in 11 patients on PYP-SPECT, in 2 patients on PI, and in 3 patients on ECG and blood circulation examination; this suggests the usefulness of PYP-SPECT in detecting subclinical right ventricular infarcts (RVI). The results indicate that PYP-SPECT is of value in delineating SEI, IPI, and RVI. (Namekawa, K.)

140

201Tl scintigraphy after surgical repair of hemodynamically significant primary coronary artery anomalies  

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Nine patients with hemodynamically significant congenital coronary artery anomalies underwent surgical repair at our institution during the period 1960 to 1979. Four received diagnoses of anomalous left coronary artery arising from the pulmonary artery, while five patients had coronary artery fistulae. Stress 201Tl scintigraphy was performed on these patients 0.5 to 18 years after surgical correction as a means of assessing the adequacy of myocardial perfusion. No perfusion defects were visualized on any of the thallium studies. The surgical procedure used did not appear to influence the results of 201Tl stress imaging. Thus, these nine patients with surgically corrected primary coronary artery anomalies had no evidence of ischemia as assessed by stress thallium scintigraphy. Serial preoperative and postoperative thallium studies are now indicated to determine the role of this procedure in the management of hemodynamically significant congenital coronary artery anomalies

141

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

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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

142

The interpolated projection data estimation method improves the image quality of myocardial perfusion SPECT with a short acquisition time  

International Nuclear Information System (INIS)

The interpolated projection data estimation processing (IPDE) method increases the amount of projection data by interpolation of the projection data. We examined the usefulness of the IPDE method for 201Tl myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) with a short acquisition time. Forty patients with suspected ischemic heart disease underwent stress 201Tl-MPI SPECT. Both stress and delayed images were acquired with 4 cycles of 360 deg continuous rotation with a 90-direction setting for 14 min. The projection data used for reconstruction were all cycle data (Tl-90-14 min), 2 cycles of data (Tl-90-7 min), and 2 cycles of data processed using the IPDE method (Tl-180IPDE-7 min). This study compared the detection of the perfusion defect by the uptake score and the image quality of 201Tl-MPI SPECT using the normalized mean square error (NMSE). The uptake score of Tl-180IPDE-7 min was significantly more concordant with Tl-90-14 min in comparison to the Tl-90-7 min (p201Tl-MPI SPECT than for the stress 201Tl-MPI SPECT (p201Tl-MPI SPECT for a short acquisition time. Fur SPECT for a short acquisition time. Furthermore, the IPDE method is a simple software program that does not require any expensive equipment or use advanced algorithms. These results suggest that the IPDE method may be useful as an adjunctive method for shortening the acquisition time of 201Tl-MPI SPECT. (author)

143

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

144

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

145

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.)

146

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

Scientific Electronic Library Online (English)

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

147

Gated single-photon emission tomography imaging protocol to evaluate myocardial stunning after exercise  

International Nuclear Information System (INIS)

This study was designed to apply ECG-gating to stress myocardial perfusion single-photon emission tomography (SPET) for the evaluation of myocardial stunning after exercise. Technetium-99m sestamibi was selected as the perfusion agent and a rest/exercise 1-day protocol was employed. Fourteen patients without coronary stenosis and 33 patients with coronary stenosis were enrolled in the study. We carried out three data acquisitions with ECG-gating: a 15-min data acquisition starting 30 min after the rest injection (AC1), a 5-min acquisition starting 5 min after the stress injection (AC2) and a 15-min acquisition starting 20 min after the stress injection (AC3). Calculation of left ventricular ejection fraction (LVEF) values was performed by means of automatic determination of the endocardial surface for all gating intervals in the cardiac cycle. Measured global EF values in 14 patients without coronary stenosis were 52.3%±7.6% (AC1), 60.6%±8.9% (AC2) and 55.6%±5.6% (AC3), and those in 11 patients with severe ischaemia were 53.6%±8.0% (AC1), 45.6%±12.1% (AC2) and 49.7%±10.7%. The magnitude of the depression of post-stress LVEF relative to the rest LVEF correlated with the severity of ischaemia (r=0.594, P=0.002), and segments manifesting post-stress functional depression were associated with ischaemic segments showing reversible perfusion defects. Stress myocardial perfusion SPET with ECG-gating is a feasible method for the evaluation of myocardial stunning as wellation of myocardial stunning as well as exercise-induced ischaemia. (orig.)

148

Usefulness of dynamic 201TlCl SPECT for differential diagnosis of ring-enhancing brain lesions  

International Nuclear Information System (INIS)

Glioblastoma (GB), metastatic brain tumor (ME), and brain abscess (AB) show ring enhancement on imaging, and their differentiation is difficult. We performed dynamic 201TlCl SPECT in patients with these 3 diseases, and investigated the diagnostic usefulness of differences in their accumulation dynamics. The subjects were 41, 37, and 11 patients with GB, ME, and AB, respectively, who underwent single photon emission tomography (SPECT). Dynamic scan every minute for 15 minutes was initiated immediately after the administration of 201TlCl. All data for the 15 minutes were added up and designated as static data, and the thallium index (TL index) was calculated from the ratio of uptake in the tumorous region to that in the contralateral normal brain region. Data per minute were summed every 3 minutes and designated as dynamic data, and the time-activity ratio curve (TARC) was drawn using the tumor/contralateral normal brain uptake ratio. The TARC was approximated to a linear function, and its slope was compared between the 3 disease groups. The TL index was 5.16±1.95 (mean±standard deviation (SD)) in GB, 3.63±1.71 in ME, and 2.60±1.52 in AB, showing a greater uptake in GB than in ME and AB (p201TlCl uptake in GB (p201Tvel and dynamics of 201TlCl uptake in tumors by dynamic 201TlCl SPECT may be a simple, useful evaluation method for the differential diagnosis of ring-enhancing brain lesions. (author)

149

Evaluation of exercise thallium-201 myocardial single photon emission computed tomography in silent myocardial ischemia  

International Nuclear Information System (INIS)

To evaluate the diagnostic significance of exercise Tl-201 myocardial SPECT in silent myocardial ischemia, 41 patients with angiographically-proven coronary artery disease (27 effort angina, 14 postinfarction angina) were tested using this method. Double product (blood pressure x heart rate) during exercise was used as a hemodynamic parameter. Thirty-two projections were obtained throughout 180 degrees by a rotating gamma camera, immediately, and four hours after exercise. Myocardial Tl-201 washout rate of the entire left ventricle was presented in two-dimensional polar function maps. Normal lower limit of myocardial Tl-201 washout rate was defined as mean-2SD of normals, and the region with a washout rate lower than normal was defined as an ischemic region. The location of myocardial ischemia was visually determined using a Bull's eye polar map. The ischemic size was quantified by the defect volume ratio (ratio of the ischemic myocardium to total myocardium). Coronary lesions were quantitatively assessed by the Pujadas score using coronary angiography. Results were as follows: There was no significant difference between painful myocardial ischemia and silent myocardial ischemia according to double product and the Pujadas scores. In most silent ischemia, the region of the reduced washout rate was in the inferior or lateral area of the Bull's eye polar map, whereas it was in the anterior area in painful ischemia . The defect volume ratio indicating the extent of ischemlume ratio indicating the extent of ischemia was smaller in silent ischemia than in painful ischemia. In conclusion, the ischemic location and size may be contributing factors in silent myocardial ischemia. (author)

150

Gated single-photon emission tomography imaging protocol to evaluate myocardial stunning after exercise.  

Science.gov (United States)

This study was designed to apply ECG-gating to stress myocardial perfusion single-photon emission tomography (SPET) for the evaluation of myocardial stunning after exercise. Technetium-99m sestamibi was selected as the perfusion agent and a rest/exercise 1-day protocol was employed. Fourteen patients without coronary stenosis and 33 patients with coronary stenosis were enrolled in the study. We carried out three data acquisitions with ECG-gating: a 15-min data acquisition starting 30 min after the rest injection (AC1), a 5-min acquisition starting 5 min after the stress injection (AC2) and a 15-min acquisition starting 20 min after the stress injection (AC3). Calculation of left ventricular ejection fraction (LVEF) values was performed by means of automatic determination of the endocardial surface for all gating intervals in the cardiac cycle. Measured global EF values in 14 patients without coronary stenosis were 52.3% +/- 7.6% (AC1), 60.6% +/- 8.9% (AC2) and 55.6% +/- 5.6% (AC3), and those in 11 patients with severe ischaemia were 53.6% +/- 8.0% (AC1), 45.6% +/- 12.1% (AC2) and 49.7% +/- 10.7%. The magnitude of the depression of post-stress LVEF relative to the rest LVEF correlated with the severity of ischaemia (r = 0.594, P = 0.002), and segments manifesting post-stress functional depression were associated with ischaemic segments showing reversible perfusion defects. Stress myocardial perfusion SPET with ECG-gating is a feasible method for the evaluation of myocardial stunning as well as exercise-induced ischaemia. PMID:10638404

Hashimoto, J; Kubo, A; Iwasaki, R; Iwanaga, S; Mitamura, H; Ogawa, S; Kosuda, S

1999-12-01

151

Experimental considerations of myocardial single photon emission CT image with a cardiac phantom  

International Nuclear Information System (INIS)

We studied the quantity of thallium-201 myocardial single photon emission CT (SPECT) image with a cardiac phantom. The myocardial SPECT image is influenced by several causes, i.e., the absorption of gamma rays, collimator aperture, statistical noise and limited angle of rotation in data acquisition. The attenuation correction under the assumption of uniform distribution is not sufficient, so we have to consider the actual distribution of absorption. The effects of the nonuniform attenuation are most prominently appeared when we evaluate the quantity by the integral method. The aperture characteristics of a collimator are decided by the distance between the rotational center of the gamma camera and the collimator surface. Simultaneously scattered gamma rays affect the reconstructed image in the low frequency component, so the effective attenuation coefficient varies gradually. The statistical noise intermixed in the projection data generate artifacts like as lumpshaped pattern. The noise are clearly appeared in the spatial frequency upper than 0.25 cycle, so the low-pass filter are required with that of cut-off frequency. Moreover to enhance the details of the radionuclide distribution of cardiac muscle, the Wiener filter should be applied. The scan area also affects the appearance of the artifact in the myocardial SPECT image. The 180-degree scan usually generates false defects just nearby the center of reconstructed cross section. And the positions are changed with ttion. And the positions are changed with the conditions of gamma ray absorber and its relative position to the myocardial area. The 360-degree scan should be used from the standpoint of reconstructing more quantitative image. (author)

152

Gated single-photon emission tomography imaging protocol to evaluate myocardial stunning after exercise  

Energy Technology Data Exchange (ETDEWEB)

This study was designed to apply ECG-gating to stress myocardial perfusion single-photon emission tomography (SPET) for the evaluation of myocardial stunning after exercise. Technetium-99m sestamibi was selected as the perfusion agent and a rest/exercise 1-day protocol was employed. Fourteen patients without coronary stenosis and 33 patients with coronary stenosis were enrolled in the study. We carried out three data acquisitions with ECG-gating: a 15-min data acquisition starting 30 min after the rest injection (AC1), a 5-min acquisition starting 5 min after the stress injection (AC2) and a 15-min acquisition starting 20 min after the stress injection (AC3). Calculation of left ventricular ejection fraction (LVEF) values was performed by means of automatic determination of the endocardial surface for all gating intervals in the cardiac cycle. Measured global EF values in 14 patients without coronary stenosis were 52.3%{+-}7.6% (AC1), 60.6%{+-}8.9% (AC2) and 55.6%{+-}5.6% (AC3), and those in 11 patients with severe ischaemia were 53.6%{+-}8.0% (AC1), 45.6%{+-}12.1% (AC2) and 49.7%{+-}10.7%. The magnitude of the depression of post-stress LVEF relative to the rest LVEF correlated with the severity of ischaemia (r=0.594, P=0.002), and segments manifesting post-stress functional depression were associated with ischaemic segments showing reversible perfusion defects. Stress myocardial perfusion SPET with ECG-gating is a feasible method for the evaluation of myocardial stunning as well as exercise-induced ischaemia. (orig.)

Hashimoto, Jun; Kubo, Atsushi; Iwasaki, Ryuichiro [Keio Univ., Tokyo (Japan). Dept. of Radiology; Iwanaga, Shiro; Mitamura, Hideo [Keio Univ., Tokyo (Japan). Dept. of Internal Medicine; Ogawa, Satoshi; Kosuda, Shigeru [National Defense Medical Coll., Saitama (Japan). Dept. of Radiology

1999-12-01

153

Analysis of coronary hemodynamics in exercise by 201Tl scintigraphy  

International Nuclear Information System (INIS)

From our observation that initial distribution of 201Tl in tissue is mainly dependent on blood flow distribution, we designed the method to obtain the rates of change of coronary blood flow and coronary vascular resistance and applied it to the analysis of coronary hemodynamics in patients with ischemic heart disease during submaximal exercise. We measured the rates of change of cardiac output (? CO) and myocardial blood flow distribution (? Fract) in two occasions by the sequential two injections of Tl, and obtained the rate of change of coronary blood flow (? Flow) from ? CO and ? Fract. Using the rate of change of mean blood pressure, we calculated also the rate of change of coronary vascular resistance (? CVR). The initial components of histograms of the right ventricle by the first and second injections of Tl were fitted into gamma function curve. S1 and S2 were the areas bounded by the curve and baseline of the first and second injections, and then the cardiac output ratio was estimated by R x S1/S2, where R was the dose ratio measured by another camera system. The five min count rates on the myocardium by the first (H1) and second (H2) injections of Tl were calculated five min after the injection. H2 was approximately H1 x R in the same condition of Tl injection but H2 was not equal to H1 x R, when the Tl injection was done in the diffee Tl injection was done in the different loading condition. Therefore the rate of change of myocardial blood flow distribution was calculated as ? Fract = (H1 x R - H2)/H2. With submaximal exercise the increases in ? CO, ? Fract and ? Flow were smaller in patients with ischemic heart disease (IHD) than those in control subjects. In the patients with IHD, there was response of lesser degree in ? Flow under increased myocardial oxygen demand, suggesting low coronary reserve in this condition. (author)

154

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

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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 {sup 201}Tl-SPECT and {sup 18}FDG-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 {sup 201}Tl-SPECT and {sup 18}FDG-PET, we evaluated the presence or absence of myocardial ischemia. We calculated the Standardized Uptake Value (SUV) (%dose/ml) of {sup 18}FDG, 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 {sup 201}Tl-SPECT and {sup 18}FDG-PET showed that hypoperfusion of {sup 201}Tl was found in 17 of 24 (71%) patients during {sup 201}Tl-loaded myocardial scanning together with redistribution of {sup 201}Tl at the same regions; {sup 18}FDG-uptake were found in all 24 patients during {sup 18}FDG-PET performed under resting and fasting conditions; the SUV of {sup 18}FDG 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)

Satake, Osamichi [Kanazawa Medical Univ. (Japan)

1999-03-01

155

A technique of quantifying lung uptake of 201Tl on the scintigram with 201TlCl  

International Nuclear Information System (INIS)

On intravenous administration of 201TlCl (74 MBq (2 mCi)), initial transit of it through the heart as well as subsequent uptake by the chest were recorded in the supine position using a scintillation camera coupling to a small digital computer, and remaining the patient in the same position perfusion scintigram with sup(99m)Tc-macroaggregated albumin (MAA) or transmi ssion scintigram with a point source of sup(99m)TcO4- too. The radioactivity of total injected dose of 201Tl (T) was calculated from the entire region on the initial transit of the tracer bolus through the heart, and that of unilateral lung (L) was done from the anterior image of 201Tl on which isocount map of the perfusion image or transmission one was superimposed. By these procedures, the lung uptake ratio of 201Tl was calculated by ratio of L/T, and expressed as percentage per entire unilateral lung and mean value (%) per pixel. The average values of the lung uptake ratio in circulatory diseases were 4.0 +- 1.2% in the right lung, 2.7 +- 1.2% in the left lung, and in respiratory diseases 4.5 +- 2.1% and 2.3 +- 1.0%, respectively. This technique is useful to quantify the lung uptake of 201Tl on the lung scintigram with 201TlCl. (author)

156

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.)

157

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.)

158

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)

159

Clinical evaluation of thyroid scintigraphy with 201Tl chloride  

International Nuclear Information System (INIS)

Cold nodule demonstrated on the thyroid scan with sup(99m)TcO4- or 131I were imaged with 201Tl chloride. Fourty-eight patients were confirmed histologically and studied whether 201Tl accumulated or not. Thyroid cancers, adenomas and chronic thyroiditis were visualized as positive in 100%, 75.0% and 100% respectively. It was valuable for the diagnosis that all of cystic degeneration of thyroid adenomas were visualized as negative. Further-more, we classified 4 types based on the correlation between conventional thyroid scan and 201Tl thyroid scan. This classification suggested probable diagnosis of nodular goiter. Five of 6 cases of metastasis of thyroid cancer showed as positive nevertheless these lesions were not detected with 131I. (author)

160

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

161

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.)

162

Attenuation correction in pulmonary and myocardial single photon emission computed tomography  

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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

163

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

Science.gov (United States)

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.

Skiadopoulos, S.; Karatrantou, A.; Korfiatis, P.; Costaridou, L.; Vassilakos, P.; Apostolopoulos, D.; Panayiotakis, G.

2009-10-01

164

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

165

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

166

Production of 201TlCl injection with diethylammonium diethyldithiocarbamatebutylacetate extraction method  

International Nuclear Information System (INIS)

The extraction of Pb and Tl(I) with butylacetate solution of diethylammonium diethyldithiocarbamate (DDDC) is studied. The DDDC-butylacetate extraction method for 201TlCl injection production from natural Tl target irradiated by 29-22 MeV proton beam is developed. 201Pb is separated from 0.3-0.4 mol/l HNO3 solution of Tl target with 0.2% DDDC-butylacetate and stripped into 4.5 mol/l HCl. The accumulated 201Tl is then oxidated to Tl(III) with KBrO3 and separated from Pb-activity with butylacetate extraction and finally, is stripped back into diluted H2SO3. The results of 18 production runs of total amount 3.18 x 1010 Bq show that the quality of all injections meets the requirements of the United States Pharmacopoeia. The chemical yield is 84% +- 2%, while the chemical separation time is 2.5-3h. The method can also be used for production of 203Pb with the chemical yield of 84% +- 3% and nuclear purity of >99.9%. The results of safety test, biodistribution in mice and rabbit imaging of the injections are good. The clinical experiments of 124 cases are performed. The quality of myocardial images and the efficiency of diagnoses are satisfactory

167

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

168

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

International Nuclear Information System (INIS)

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)

169

201Tl production from lead exposed to 65 MeV protons  

International Nuclear Information System (INIS)

The 201Tl, 200Tl and 202Tl yields from target of natural lead and enriched 206Pb and 2H07Pb exposed to 65 MeV proton beam have been studied. A thick 206Pb target (2.6 g/cm2) is shown to yield 4.1+-0.5 mCi/?A-hr of 201Tl with the radionuclide purity of 95-96%. Possible application of this 201Tl in nuclear medicine is discussed

170

Automatic detection of the left ventricular myocardium long axis and center in thallium-201 single photon emission computed tomography  

International Nuclear Information System (INIS)

A new method for centering and reorienting automatically the left ventricle in thallium-201 myocardial single photon emission tomography (SPECT) is proposed. The processing involves the following steps: (a) The transverse sections of the left ventricle are segmented, (b) the three-dimensional skeleton of the left ventricle is extracted using tools of mathematical morphology, (c) the skeleton is fitted to a quadratic surface by the least-squares method, (d) the left ventricle is reoriented and centered using the long axis and the coordinates of the centre of the quadratic surface. A series of 30 consecutive exercise and redistribution 201Tl SPECT studies were centered and reoriented by two operators twice with this method, and twice manually. There was no significant difference in the mean realignment performed by the automatic and the manual methods while centering differed moderately in some instances. In all cases and for all parameters, the reproducibility of the automatic method was 1.00, while it ranged between 0.74 and 0.98 with the manual centering and reorientation. This automatic approach provides a fast and highly reproducible method for the reconstruction of short- and long-axis sections of the left ventricle in 201Tl SPECT. (orig.)

171

Automatic detection of the left ventricular myocardium long axis and center in thallium-201 single photon emission computed tomography  

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A new method for centering and reorienting automatically the left ventricle in thallium-201 myocardial single photon emission tomography (SPECT) is proposed. The processing involves the following steps: (a) The transverse sections of the left ventricle are segmented, (b) the three-dimensional skeleton of the left ventricle is extracted using tools of mathematical morphology, (c) the skeleton is fitted to a quadratic surface by the least-squares method, (d) the left ventricle is reoriented and centered using the long axis and the coordinates of the centre of the quadratic surface. A series of 30 consecutive exercise and redistribution [sup 201]Tl SPECT studies were centered and reoriented by two operators twice with this method, and twice manually. There was no significant difference in the mean realignment performed by the automatic and the manual methods while centering differed moderately in some instances. In all cases and for all parameters, the reproducibility of the automatic method was 1.00, while it ranged between 0.74 and 0.98 with the manual centering and reorientation. This automatic approach provides a fast and highly reproducible method for the reconstruction of short- and long-axis sections of the left ventricle in [sup 201]Tl SPECT. (orig.).

Cauvin, J.C.; Boire, J.Y.; Maubliant, J.C.; Bonny, J.M.; Zanca, M.; Veyre, A. (Centre Jean Perrin, 63 - Clermont-Ferrand (France). Div. of Nuclear Medicine ERIM-INSERM U-71, 63 - Clermont-Ferrand (France))

1992-12-01

172

Myocardial uptake of thallium-201 diethyldithiocarbamate (Tl-201-DDC) in cultured heart cells and in humans  

International Nuclear Information System (INIS)

We assessed the feasibility of SPECT imaging with 201Tl-diethyldithiocarbamate (201Tl-DDC), a new cerebral blood flow tracer with little redistribution, expecting to observe less extensive redistribution than with 201Tl-chloride. Myocardial sections were obtained in three patients presenting with documented coronary artery disease and injected at peak exercise with 100 MBq 201Tl-DDC. In two patients there was a clear redistribution phenomenon at four h after injection. In cultured myocardial cells of newborn rats, the uptake and washout of 201Tl-chloride and 201Tl-DDC were compared. The 201Tl-DDC uptake was lower than 201Tl-chloride (transmembrane gradients were respectively 89±10 and 4.1±0.2, mean±sem, n=14, P201Tl-chloride in the cells was 4% vs 19% for 201Tl-DDC. It is concluded that although myocardial imaging is feasible with 201Tl-DDC, this agent redistributes significantly with time. (orig.)

173

Imaging of parathyroid adenoma with 201Tl-99mTc subtraction scintigraphy  

International Nuclear Information System (INIS)

Difficulties of preoperative localization of parathyroid adenomas may lead to incomplete surgical removal. To avoid it a nuclear technique is proposed. It is performed via 201Tl-99mTc dual isotope subtraction scintigraphy. A case of parathyroid adenoma diagnosed by this method and confirmed histologically is presented. 74 MBq 201Tl-Cl was administered, followed by the administration of 40 MBq Na99mTcO4. Gamma camera images were taken and computer analyzed by subtracting the 99mTc image from the 201Tl image. The excess 201Tl activity obtained is characteristic of the parathyroid adenoma. (author) 19 refs.; 8 figs

174

Technetium-99m sestamibi single-photon emission tomography detects subclinical myocardial perfusion abnormalities in patients with systemic lupus erythematosus  

International Nuclear Information System (INIS)

In patients with systemic lupus erythematosus, involvement of the cardiovascular system is the third leading cause of death. However, although autopsy studies have demonstrated a high incidence of abnormalities in both the myocardium and coronary vessels, clinical manifestations have been reported in only a small percentage of cases. The aim of this study was to evaluate myocardial perfusion in asymptomatic lupus patients using technetium-99m sestamibi single-photon emission tomography (SPET). Twenty-eight patients without overt cardiac involvement and risk factors were studied with 99mTc-sestamibi SPET at rest and after dipyridamole infusion. Perfusion abnormalities were detected in 18 cases: six had persistent defects, three had reversible defects, seven had both persistent and reversible defects, and two showed rest defects which normalized on dipyridamole images (''reverse redistribution pattern''). Coronary angiography was performed in eight patients with positive 99mTc-sestamibi SPET, and showed normal epicardial vessels in all the cases. These results indicate that 99mTc-sestamibi SPET reveals a high prevalence (18 out of 28 patients in this study, i.e. 64%) of myocardial perfusion abnormalities in asymptomatic lupus patients, probably due to the primary immunological damage of this autoimmune disease. In conclusion, rest/dipyridamole 99mTc-sestamibi SPET can be a useful non-invasive method to identify subclinical myonvasive method to identify subclinical myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events. (orig.)

175

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

International Nuclear Information System (INIS)

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)

176

Comparison with normal database (NDB) is important to objectively assess myocardial perfusion  

International Nuclear Information System (INIS)

We understand comparison with Normal-data-base (NDB) objectively assess for myocardial perfusion imaging (MPI) is important. Generally, we use default NDB, however might be seen false-positive to depend on kind, collimator, and conditions. Therefore we made our NDB and compared with default and another NDB. We identified 105 consecutive patients who underwent stress 201Tl single photon emission computed tomography (SPECT) between October, 2008 to January, 2010, whose SPECT had normal image. Our NDB presented big differences to default NDB. We think making NDB in each hospital is necessary to evaluate more accuratel. (author)

177

Quantitative evaluation of intermittent claudication by 201Tl perfusion scintigraphy  

International Nuclear Information System (INIS)

Present attempt was to define intermittent claudication objectively by quantitative assessment of 201Tl perfusion scintigraphy of leg both at rest and exercise loading. After intravenous injection of 201Tl with or without exercise loading by treadmil the distribution of this tracer throughout body was obtained using a whole body scanner. According to the indicator fractionation principle, regional blood flow of cardiac output (rBF/co) for each segment of the legs was expressed as a fractional deposited radioactivity (rFU) at these segments of that of whole body. Validity of the principle was confirmed by comparing the deposited activity of 201Tl with that of sup(99m)Tc-MMA and a good correlation was found (r = 0.979). rFU in normals was 5.49 x 0.69% (total leg) 3.57 x 0.49% (thigh) and 1.59 x 0.34% (calf) at rest and 19.40 x 2.04% (total leg) 12.26 x 1.91% (thigh) and 6.58 x 0.99% (calf) during exercise. The change ration from the rest to the exercise (?rFU) was 3.41 x 0.45 (total leg) 3.44 x 0.61 (thigh) and 4.30 x 1.30 (calf). In patient with known ASO and TAO rFU was within normal range at rest but duing exercise ?rFU was significantly less than that of normal (1.95 x 0.40 in the total leg of ASO p < 0.001; 1.82 x 0.47 in the total leg of TAO p < 0.001). A defect or decreased activity on the stress scintigraphy of the legs was wall correlated with the angiographic findings. (author)

178

Transverse CAT of the myocardium with 201 Tl  

International Nuclear Information System (INIS)

A new computerized axial tomographic (CAT) scanner (J and P Tomoscanner) which enables the transverse section viewing of any organ labelled by one of the monophotonic gamma-ray emitting tracers commonly used in Nuclear Medicine, has been recently commercialized. Its abilities in visualing the 201 Tl labelled myocardium are evaluated with normal hearts and patients with documented infarctions. Positive results have been obtained, allowing an interesting approach to the estimation of the anatomical extent of necrosis. (orig.) 891 MG/orig. 892 MBE

179

Giant dipole resonance in $^{201}$Tl at low temperature  

CERN Document Server

The thermal pairing gap obtained by embedding the exact solutions of the pairing problem into the canonical ensemble is employed to calculate the width and strength function of the giant dipole resonance (GDR) within the phonon damping model. The results of calculations describe reasonably well the data for the GDR width as well as the GDR linearized strength function, recently obtained for $^{201}$Tl in the temperature region between 0.8 and 1.2 MeV, which other approaches that neglect the effect of non-vanishing thermal pairing fail to describe.

Dang, Nguyen Dinh

2012-01-01

180

Thallium-201 myocardial imaging with single photon emission CT in Kawasaki disease  

International Nuclear Information System (INIS)

Seventy-five patients with Kawasaki disease underwent single photon emission computed tomography (SPECT) and planar imaging with thallium-201 after dipyridamole in order to evaluate the usefulness of detecting the complication of coronary artery disease (CAD). The results of SPECT with a three reconstruction imaging study (short axis, vertical long axis, horizontal long axis) and of planar imaging study with thallium-201 were compared with coronary angiography. The overall sensitivity of detecting CAD was 86.7% with SPECT and 66.7% with planar imaging. The sensitivity in identifying individual vessels was 76.0% with SPECT and 44.0% with planar imaging. SPECT was especially superior to planar imaging in detecting localized stenosis. (53.8% vs 15.4%) The specificity of SPECT did not differ from the planar imaging study. Dipyridamole thallium-201 SPECT is a useful non-invasive method to detect CAD due to Kawasaki disease. (author)

181

Correlation of MIB-1 staining index and 201Tl-SPECT retention index in preoperative evaluation of malignancy of brain tumors  

International Nuclear Information System (INIS)

MIB-1 staining provides a useful index of the malignancy of brain tumors. However, because of the difficulty of evaluating malignancy based on the preoperative imaging findings, we investigated the correlation between the 201Tl-single photon emission computed tomography (SPECT) retention index (RI) and MIB-1 staining index (MIB-1 SI) to determine the usefulness of RI for preoperative evaluation of the malignancy of brain tumors. The subjects of this study were 47 patients who underwent tumor removal surgery at our hospital in 2006 and 2007. The tumors consisted of 16 intraaxial tumors (all gliomas: 9 glioblastomas, 2 anaplastic astrocytomas, 2 anaplastic oligoastrocytomas, 1 oligodendroglioma, and 2 ependymomas), 8 other malignant brain tumors, and 23 extraaxial tumors (10 meningiomas, 7 pituitary adenomas, and 6 schwannomas). The mean RI and mean MIB-1 SI of the intraaxial tumors were 0.628% and 32.0%, respectively, and after MIB-1 SI was converted to the natural logarithm (log MIB-1 SI), Pearson's coefficient for the correlation between them was significant (r=0.752, P201Tl-SPECT RI values wand the 201Tl-SPECT RI values were useful as an index of malignancy. RI values may also be useful for evaluating apparently benign extraaxial tumors for possible malignancy. (author)

182

A mechanism for myocardial uptake of /sup 201/Tl  

International Nuclear Information System (INIS)

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

183

A paper chromatographic technique for quantitative evaluation of hydrolysed and ionic components in 201Tl radiopharmaceuticals  

International Nuclear Information System (INIS)

A reported paper chromatographic technique has been extended to delineate the hydrolysed components in 201Tl radiopharmaceuticals for the determination of radiochemical purity. Detailed radiochemical purity analysis of 201TlCl has been demonstrated using mini paper chromatographic systems. The technique is also useful in evaluation of the radiochemical purity of 67Ga and 111In radiopharmaceuticals

184

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

International Nuclear Information System (INIS)

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.)

185

The quantitative evaluation of 201Tl-uptake in the pulmonary extravascular space  

International Nuclear Information System (INIS)

201TlCl chest scintigraphy was performed in 10 patients with various heart and lung diseases, and 201Tl clearances of blood and lung were studied too. Soon after the injection of 201Tl, serial images of the whole chest were recorded in the supine position using a scintillation camera with a small digital computer. Total injected dose (T) was obtained from the maximum radioactivity in the serial images, and that in both lungs (L) was calculated from the anterior image on which the iso-count map of the perfusion lung scintigram was superimposed. Then the lung uptake ratio (%) was calculated by ratio of L/T. Using both scintigrams with 201Tl and sup(99m)Tc-human serum albumin, the image of 201Tl in the extravascular space was obtained, and subtracting this image from the original image of 201Tl, the one in the pulmonary extravascular space was obtained. Following results were obtained; 1) The disappearance of 201Tl from the blood was rapid, and 15 minutes after the injection only 10-15% of the radioactivity after 1 minute was present. 2) The lung activity of 201Tl on the time activity curve decreased rapidly to reach near plateau within 100-150 seconds after the injection, but slight and gradual decrease of it continued for 30 minutes. 3) The image of 201Tl in the extravascular space was almost the same as the original image of 201Tl as regard to the pattern of 201Tl as regard to the pattern of 201Tl-distribution. 4) The lung uptake ratio of 201Tl in the pulmonary extravascular space and original image were 9.8+-5.2% and 10.1+-5.3% as mean +-SD, respectively. So the former was 96.8+-2.4% of the latter. 5) The grade of lung uptake of 201Tl was seemed to be a useful index showing the disease process in the pulmonary extravascular space of cardiorespiratory diseases. (author)

186

Clinical application of 201Tl scintigraphy in patients with cold thyroid nodules  

International Nuclear Information System (INIS)

201Tl-chloride scintigraphy was performed in 45 patients with cold thyroid nodules. The 201Tl scintigram was positive in 17 of 18 thyroid patients with cancer (94.4%), 8 of 20 patients with an adenoma (40.0%), 1 of 2 adenomatous goiter patients (50.5%), and all of 5 cases of chronic thyroiditis (100.0%). When the cold nodule was demonstrated to be positive with 201Tl, the statistical chance of the lesion being a cellular one was 100.0% and a risk of its malignancy was 54.8%. On the other hand, the nodule with negative 201Tl concentration had a 14.3% chance of cellularity and a 7.1% risk of malignancy. Thus, 201Tl scintigraphy is of use in the differential diagnosis of the cold thyroid nodule

187

Single photon emission computed tomography of technetium-99m tetrofosmin myocardial perfusion imaging in patients with systemic lupus erythematosus-A preliminary report  

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the utility of single-photon emission computed tomography (SPECT) of technetium-99m tetrofosmin (Tc-99m TF) myocardial perfusion imaging to detect myocardial involvement in patients with systemic lupus erythematosus (SLE). Three groups of subjects-group 1: 25 SLE female patients with non-specific cardiac symptoms and signs, group 2: 25 female SLE patients without any cardiac symptoms and signs, and group 3: 25 female healthy controls-were evaluated by comparing rest and dipyridamole-stress Tc-99m TF myocardial perfusion SPECT. Tc-99m TF myocardial perfusion SPECT revealed perfusion defects in 88% and 40% of the cases in groups 1 and 2, respectively. However, no cases in group 3 demonstrated myocardial perfusion defects. Tc-99m TF myocardial perfusion SPECT is a useful noninvasive imaging modality to detect cardiac involvement in SLE patients with or without cardiac symptoms and signs. (author)

188

Cardiofocal collimators for gated single-photon emission tomographic myocardial perfusion imaging  

International Nuclear Information System (INIS)

In this article the feasibility and accuracy of gated SPET myocardial perfusion imaging using a triple-head camera equipped with CFC, is evaluated. Twenty patients with a history of myocardial infarction were studied. SPET myocardial perfusion images, gated in eight time bins, were acquired in a random sequence with a PHC and a CFC for each patient. Imaging was started 60 min after the injection of 925 MBq of technetium-99m tetrofosmin at rest. The extent (EXT) and severity (SEV) of perfusion defects were quantified on polar maps using the non-gated data. Left ventricular volumes [end-diastolic volume (EDV), end-systolic volume (ESV)] and ejection fraction (LVEF) were calculated from gated data using the Cedars-Sinai program. In 17 of 20 patients the complete left ventricle was positioned within the useful field of view of the CFC. The results in respect of perfusion, volumes and ejection fraction were almost identical to those obtained with the PHC. The mean difference±SD between the CFC and the PHC was -2.30±7.16 (% of LV area) for EXT, -0.48±2.90 for SEV (arbitrary units), -1,50±5.25 (ml) for EDV and 0.53±4.10 (%) for LVEF. The largest differences in EXT and LV volumes were observed in patients in whom a part of the LV was not positioned within the useful field of view. We conclude that, for the mfjority of patients, identical information with regard to both perfusion and function can be derived from gated SPET myocardial perfusion studies obtained with PHCs oerfusion studies obtained with PHCs or with CFCs. Because of the greater sensitivity, however, a much shorter acquisition time is required with CFCs. (orig.)

189

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.)

190

Quantitative evaluation of thallium-201 myocardial single photon emission CT (SPECT)  

International Nuclear Information System (INIS)

We developed a new method for the quantitative evaluation of Tl-201 myocardial SPECT. Circumferential profile analysis was performed on the short axial slices from the apex to the base. Derived profile curves were changed into 9 curves by interpolation. The data were displayed on 9 concentric circles, providing Concentric Circular Display (CCD). From twenty subjects with normal coronary arteriogrephy mean and standard deviation (SD) were calculated at each points of the 9 curves. Defect score (DS) was the number of points below mean - 2 SD of the normal values. CCD analysis by the criterion of DS (? 9) was compared with visual analysis (VA) in detectability of coronary artery disease (CAD). In AP (n = 65) sensitivity was 83 % and 77 % in CCD and VA, respectively, while 100 % and 98 % in MI (n = 47). Specificity was 69 % and 83 % in normal subjects (n = 35). Detectability of individual coronary artery lesions was 76 % vs. 71 % for LAD and 84 % vs. 75 % for RCA and LCX. Specificity was 64 % vs. 92 % (p < 0.05) for LAD and 60 % vs. 73 % for RCA and LCX. Specificity of CCD was slightly inferior to that of visual analysis. In conclusion three dimensional information of myocardial SPECT was displayed in a two dimensional image by CCD and this makes it possible to evaluate myocardial perfusion easily and objectively. (author)

191

Genotoxicity of thallium-201 in patients with angina pectoris undergoing myocardial perfusion study  

International Nuclear Information System (INIS)

Thallium-201 (201Tl) has been widely used as a nuclear reagent for myocardial blood flow imaging. The purpose of this study was to investigate genotoxic effects of 201Tl in patients with angina pectoris (n=21), who had undergone myocardial perfusion imaging. Lymphocytes were isolated from each patient before, and 3, 30 and 90 days after 201Tl administration (111 MBq, 3 mCi) and were analyzed for chromosomal aberrations, sister chromatid exchanges, mitotic index and replicative index. There were significant increases in chromosomal aberrations and sister chromatid exchanges 3 days after 201Tl administration (p0.05). Moreover, decreased mitotic index and replicative index were noted after 3 days of 201Tl administration (p201Tl for myocardial blood flow imaging may induce genetic damage. (author)

192

Cyclotron production of Thallium-201 via the 205Tl(p,5n)201Pb ? 201Tl reaction  

International Nuclear Information System (INIS)

The production of the clinically useful 201Tl radioisotope was investigated based upon the utilization of the 205Tl(p,5n)201Pb ? 201Tl reaction. Thin-stacked metallic foils of 99.5% enriched 205Tl were used as targets. Thick-target yields for the daughters 201Tl, 200Tl, and 202Tl were calculated as a function of target thickness, bombarding time, target chemistry time, and incident proton energies. The results demonstrated the feasibility of utilizing the (p,5n) reaction to produce 201Tl of similar radionuclidic composition and in yields comparable to the 203Tl(p,3n)201Pb ? 201Tl method

193

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

194

Comparative study of myocardial perfusion imaging by TL-201 single-photon ECT and N-13 ammonia positron CT  

International Nuclear Information System (INIS)

Thallium (Tl) single-photon emission CT (SPECT) has been available for three-dimensional evaluation of myocardial perfusion. To assess the value and limitation of Tl SPECT, the images were compared with N-13 ammonia positron CT(PCT) in phantom and clinical studies. SPECT was performed by gamma camera rotation over 1800 after Tl 2 mCi injection. PCT was performed using 4 detector ring whole-body PCT device after N-13 ammonia 20 mCi injection. Acquisition time was 16 min for SPECT and 20 min (transmission) plus 10 min (emission) for PCT. No attenuation correction was done in SPECT, while in PCT it was accurately performed from the transmission data. Collected counts in a single slice were 100-180K by SPECT and 5-12M by PCT. The spatial resolution was about 16 mm for SPECT and 8 mm for PCT in FWHM. Because of better resolution and higher count statistics, PCT delineated fine cardiac structures, such as papillary muscles and apical thinning, while the myocardium looked thicker in SPECT due to poorer resolution. Regional distribution was comparatively evaluated by circumferential profile methods in the same plane in 5 normal cases. As compared to PCT, Tl distribution was less in the septal and posterior regions, and more in the lateral region due to photon attenuation. The authors conclude that Tl SPECT provides poorer images due to inadequate count density with poor resolution, as compared to PCT. It has severe limitation for quantitative evaluation of myocardion for quantitative evaluation of myocardial perfusion. However, one of the advantages of SPECT is that cardiac short-axis and long-axis sections can easily be reorganized

195

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

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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

196

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

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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 [mu]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).

Karasawa, Kensuke; Ayusawa, Mamoru; Noto, Nobutaka; Yamaguchi, Hideo; Okada, Tomoo; Harada, Kensuke (Nihon Univ., Tokyo (Japan). School of Medicine)

1994-05-01

197

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

198

Leg arteritis exploration by quantitative muscle scintigraphy with 201Tl  

International Nuclear Information System (INIS)

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

199

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

International Nuclear Information System (INIS)

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)

200

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

International Nuclear Information System (INIS)

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)

201

Preparing 201Tl from lead bombarded by protons of energy about 65 MeV  

International Nuclear Information System (INIS)

Measurements have been made on the yields of 201Tl, 200Tl, and 202Tl from targets made of natural lead and ones enriched in 206Pb and 207Pb, which have been bombarded by protons of energy about 65 MeV. A thick 206Pb target (2.6 g/cm2) gave 201Tl with a yield of 15 +/- 2 x 107 Bq/?A x h and of radionuclide purity 95-96%. There is a discussion of using 201Tl made from 206Pb for nuclear-medicine purposes

202

The evaluation of 201TlCl and delayed scan for thyroid imaging agent  

International Nuclear Information System (INIS)

The results of 189 patients with nodular goiter by imaging with 201TlCl following with sup(99m)TcO4- was presented. Accumulation of 201TlCl to the corresponding area was observed in 85.5% of cancer, 62.2% of adenoma, 42.5% of adenomatous goiter, and the usefulness of 201TlCl (early scan) for thyroid imaging agent was recognized. On the other hand, delayed scan for purpose of differentiation from benign to malignant was also performed. However, no significant differences were obtained. (author)

203

Evaluation of myocardial function with the 201 Thallium scintimetry in various diseases of the heart. A correlative study based on 100 patients  

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To assess the validity of the quantitative /sup 201/Tl scintimetry in various diseases of the heart (coronary heart disease with and without myocardial infarction, non-coronary cardiomyopathy, scleroderma heart disease and asymmetric septal hypertrophy with IHSS), the /sup 201/Tl myocardial uptake values for five standardized projections (a) were correlated with the grade of LAD stenosis, (b) the pattern of myocardial wall motion and (c) were compared with the /sup 201/Tl uptake values derived from normal patients. Significant reduction (c) of /sup 201/Tl myocardial uptake could in individual cases be evaluated in acute myocardial infarction (95%), in dys- and akinesia (90%), in hypokinesia (71%), in scleroderma heart disease (50%), in non-coronary cardiomyopathy (50%) as well as in normokinesia (28%) when associated with LAD stenosis. The mean values (b) of /sup 201/Tl uptake in normo- and hypokinesia significantly differed between these two groups and from those evaluated in dys- and akinesia. The latter group showed the lowest /sup 201/Tl uptake values computed which in some cases were very close to the mean mediastinal /sup 201/Tl uptake. The correlation (a) of individual /sup 201/Tl values demonstrated that /sup 201/Tl distribution in the myocardium is not only equivalent to myocardial ''perfusion'' but is corresponding with the myocardial function. In non-coronary cardiomyopathy reduced /sup 201/Tl values sometimes could not be separated from values in coronary heart disease (and myocardial infarction). A regional increase of myocardial mass as in septal hypertrophy correlated well with an augmented /sup 201/Tl uptake when referred to the /sup 201/Tl storage in the mediastinum.

Buell, U.; Niendorf, H.P.; Strauer, B.E.; Hast, B.

1976-08-12

204

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

International Nuclear Information System (INIS)

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

205

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

206

Time course of thallium-201 redistribution after transient myocardial ischemia  

International Nuclear Information System (INIS)

The mechanism and time course of thallium-201 (201Tl) redistribution after transient myocardial ischemia was investigated in 27 anesthetized dogs given 1.5 mCi of 201Tl intravenously 10 minutes after occlusion of the left anterior descending coronary artery. Coronary reperfusion (RP) was accomplished 10 minutes after 201Tl administration. Transmural myocardial biopsies were obtained in situ from normal (N) and ischemic (IS) regions during occlusion and 5 minutes (four dogs), 20 minutes (eight dogs), 90 minutes (six dogs), 4 hours (five dogs) and 6 hours (four dogs) after RP. There was a twofold rise in 201Tl activity (counts/10 min/mg) in the IS region after only 5 minutes of reflow with as yet no detectable change in 201Tl concentration in the N zone. In dogs undergoing 90 minutes of RP, 201Tl activity was 700 +- 150 (SEM) in the IS zone during occlusion and markedly increased (p 201T1 activity in the N region decreased only slightly, from 7000 +- 800 to 6000 +- 450 (NS). In dogs that underwent 6 hours of RP, 201Tl activity in the IS zone increased from 1700 +- 500 during occlusion to 3300 +- 200 (p 201Tl his near-equalization of 201Tl activity between N and IS zones was already apparent by 4 hours of RP. These data indicate that 201Tl redistribution after transient myocardial ischemia is related to both delayed accumulation of 201Tl into ischemic myocardial segments and to a more rapid washout of the radionuclide from normal segments

207

Clinical evaluation of 201Tl-chloride scintigraphy for breast tumors  

International Nuclear Information System (INIS)

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)

208

Evaluation of diffuse lung uptake of 201Tl in bronchopulmonary diseases  

International Nuclear Information System (INIS)

201Tl scintigraphy was performed in various bronchopulmonary diseases. Applying semiquantitative and visual assessments of grade of 201Tl lung uptake, clinical aspects of diffuse lung uptake of 201Tl was studied. Diffuse lung uptake of 201Tl was observed in various broncho-pulmonary diseases with multiple or numerous abnormal shadows in the lung fields, and obvious lung uptake was also shown even in some cases with few or no abnormal shadows. Positive results of moderate (++) and marked (+++) lung uptake of 201Tl more than 60.0% were obtained in diffuse interstitial pneumonia, hypersensitivity pneumonitis, silicosis, the disseminated type of pulmonary tuberculosis and primary lung cancer. The ratio of radioactivity of the lung (maximum) to the upper mediastinum was 1.04 ± 0.24 in healthy controls, and more than 2.0 in diffuse interstitial pneumonia, hypersensitivity pneumonitis and silicosis. The ratio of radioactivity of the right lung to the administered dose of 201Tl was 1.5 ± 0.9% in healthy controls, and more than 3.0% in diffuse interstitial pneumonia, silicosis, the disseminated type of pulmonary tuberculosis and primary lung cancer. Lung uptake of 201Tl was diffuse, homogenous and marked in diffuse interstitial pneumonia and hypersensitivity pneumonitis, while it was scattered and slight in chronic obstructive lung diseases. 201Tl scintigraphy seems to be useful for deteccintigraphy seems to be useful for detecting interstitial disorders of the lung including edema, inflammatory and granulomatous changes, especially in cases with slightly abnormal or normal chest X-ray films. (author)

209

Fundamental studies of myocardial defect size quantification using positron emission tomography and single photon emission computed tomography  

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In Flurine-18 fluorodeoxyglucose ({sup 18}F-FDG) positron emission tomography (PET) acquisition, a transmission scan is usually performed before the PET tracer injection (cold transmission method), followed by a subsequent emission scan. However, this procedure is time consuming. An alternative approach, in which the transmission scan is performed after the emission scan (hot transmission method), would significantly reduce the time required for data acquisition. Recently, three-dimensional PET acquisition (3D PET) has become available. The counting sensitivity is much higher in 3D PET than in conventional two-dimensional PET (2D PET), resulting in a shorter acquisition time and reduced radiation exposure for the patient. On the other hand, {sup 18}F-FDG imaging using single photon emission computed tomography (SPECT), a more widely available method than PET, has emerged as an alternative to PET. The purpose of this study was to investigate the accuracy of measurement of myocardial defect sizes by these new techniques, using a chest phantom. Acquisitions were performed using an elliptical cylinder chest phantom. Plastic inserts, ranging in size from 2-60% of the myocardium (n=12), were used as simulated models of transmural myocardial infarction. Fluorine-18 was given into each part of the phantom. PET imaging with cold and hot transmission methods, 3D PET, and SPECT imaging were performed with different acquisition times and different radioisotope concentrations. All PET and SPECT data were analyzed using a semiquantitative polar map approach. Defect sizes were quantified using various cutoff thresholds, and were expressed as a percentage of the left ventricular myocardium. The PET and SPECT measurements were compared with the true defect sizes. Among the various cutoff levels tested, the mean absolute difference between the measured and true defect sizes was minimal at 50% of peak activity for both PET and SPECT. The PET measurements with the hot transmission method showed an excellent correlation with true defect sizes, and the mean absolute error of measurements were similar between the hot and cold transmission methods. In particular, the mean absolute error of 3D PET measurements was smaller than 2D PET for a short acquisition time (10 seconds) and low radioisotope concentrations (25 kBq/ml and 50 kBq/ml). Finally, the SPECT measurements were similar to the PET measurements and closely correlated with the true defect sizes. In conclusion, cardiac PET imaging with these new acquisition techniques is feasible, and 3D PET is more useful than 2D PET in respect of the short acquisition times and low radioisotope concentrations. Furthermore, {sup 18}F-FDG SPECT imaging may also be useful to delineate viable myocardium from scarred myocardium in a manner similar to PET. (author)

Yoneyama, Tatsuya [Kanazawa Univ. (Japan). School of Medicine

2001-04-01

210

The evaluation of 201TlCl for thyroid imaging agent  

International Nuclear Information System (INIS)

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)

211

Effect of ribose on thallium-201 myocardial redistribution.  

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Myocardial 201Tl redistribution after transient ischemia may be too slow to allow identification of a reversible myocardial defect within the routine 201Tl imaging period. To determine whether 201Tl redistribution could be affected by a metabolic intervention, intravenous ribose was administered postischemia. Seventeen domestic swine were subjected to a 10-min ischemic period followed by either a 30-min i.v. ribose (n = 8) or saline (n = 9) infusion. Thallium-201 was injected during ischemia and myocardial 201Tl activity was continuously monitored in ischemic and nonischemic regions with miniature CdTe radiation detection probes. Coronary flow in the ischemic region was reduced to 25% of that in the nonischemic regions in both saline and ribose groups. The 201Tl time-activity curves demonstrated a significant enhancement of % 201Tl redistribution in the ribose-treated animals at the end of ribose infusion: Ribose (48 +/- 11%), Saline (20 +/- 4%), p less than 0.05. Alteration of 201Tl kinetics by ribose may permit earlier recognition of 201Tl myocardial redistribution after transient ischemia. PMID:3142974

Angello, D A; Wilson, R A; Gee, D

1988-12-01

212

Effect of ribose on thallium-201 myocardial redistribution  

International Nuclear Information System (INIS)

Myocardial 201Tl redistribution after transient ischemia may be too slow to allow identification of a reversible myocardial defect within the routine 201Tl imaging period. To determine whether 201Tl redistribution could be affected by a metabolic intervention, intravenous ribose was administered postischemia. Seventeen domestic swine were subjected to a 10-min ischemic period followed by either a 30-min i.v. ribose (n = 8) or saline (n = 9) infusion. Thallium-201 was injected during ischemia and myocardial 201Tl activity was continuously monitored in ischemic and nonischemic regions with miniature CdTe radiation detection probes. Coronary flow in the ischemic region was reduced to 25% of that in the nonischemic regions in both saline and ribose groups. The 201Tl time-activity curves demonstrated a significant enhancement of % 201Tl redistribution in the ribose-treated animals at the end of ribose infusion: Ribose (48 +/- 11%), Saline (20 +/- 4%), p less than 0.05. Alteration of 201Tl kinetics by ribose may permit earlier recognition of 201Tl myocardial redistribution after transient ischemia

213

Sodium bicarbonate-augmented stress thallium myocardial scintigraphy  

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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 {sup 201}Tl 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 {sup 201}Tl. 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 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.)

Sarin, Badal; Chugh, Pradeep Kumar; Kaushal, Dinesh; Soni, Nakse Lal; Sawroop, Kishan; Mondal, Anupam; Bhatnagar, Aseem [Department of Nuclear Medicine, Institute of Nuclear Medicine and Allied Sciences, Brig. S. K. Mazumdar Road, 110054, Delhi (India)

2004-04-01

214

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.)

215

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

216

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)

217

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

218

Separation of Tl(I)-Pb(II) by liquid-liquid extraction with diethyldithiocarbamic acid. Isolation of 201Tl  

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The production of 201Tl is described. Natural thallium is irradiated with protons and the induced 201Pb is separated from the target by liquid-liquid extraction with diethyldithiocarbamic acid in chloroform. 201Tl is separated from the mother activity (201Pb) by liquid-liquid extraction with the same reagent. The decontamination of the final product (carrier free 201TlCl) is >=5x106 from the thallium of the target and >5x104 from lead isotopes. (author)

219

The assessment of left ventricular function measured by 99mTc-MIBI gated myocardial perfusion single photon emission computed tomography with gs quant software  

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Recent computer software developments having improved the assessment of coronary artery disease (CAD) in Cardiovascular Nuclear Medicine, gated myocardial perfusion single photon emission computed tomography offers the possibility of combining completements of myocardial perfusion and ventricular ejection fraction (LVEF) within the same acquisition. The aim of this study was to investigate the clinical value of LVEF measured by 99mTc-MIBI G-SPECT with the soft ware GS Quant: The values of LVEF of three methods including G-SPECT, RNA and UCG were calculated and compared about twenty-four patients who had undergone 99mTc-MIBI gated myocardial SPECT, gated radionuclide angiocardiography and echocardiography within two weeks. The result shows that the value of LVEF drawn from 99mTc-MIBI gated myocardial perfusion SPECT has an excellent correlation with that from gated radionuclide angiocardiography or echocardiography(r=0.81, P>0.05; r=0.76, P99mTc-MIBI gated myocardial SPECT with a good reproducibility. These results support the further clinical application of gated myocardial perfusion SPECT. (authors)

220

Value and limitation of stress thallium-201 single photon emission computed tomography: comparison with nitrogen-13 ammonia positron tomography  

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The diagnostic value of exercise 201Tl single photon emission computed tomography (SPECT) for assessing coronary artery disease (CAD) was comparatively evaluated with exercise [13N] ammonia positron emission tomography (PET). Fifty-one patients underwent both stress-delayed SPECT imaging using a rotational gamma camera and stress-rest PET imaging using a high resolution PET camera. Of 48 CAD patients, SPECT showed abnormal perfusion in 46 patients (96%), while PET detected perfusion abnormalities in 47 (98%). The sensitivity for detecting disease in individual coronary arteries (greater than 50% stenosis) was also similar for SPECT (81%) and PET (88%). When their interpretations were classified as normal, transient defect, and fixed defect in 765 myocardial segments, SPECT and PET findings were concordant in 606 segments (79%). However, 66 segments showed a fixed defect by SPECT but a transient defect by PET, whereas there were only nine segments showing a transient defect by SPECT and a fixed defect by PET. PET identified transient defects in 34% of the myocardial segments showing a fixed defect by SPECT. We conclude that both stress SPECT and PET showed high and similar sensitivities for detecting CAD and individual stenosed vessels. Since stress-delayed SPECT with single tracer injection detected fewer transient defects, it may underestimate the presence of myocardial ischemia, compared with high resolution PET imaging with two tracer injectionsmaging with two tracer injections

221

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.)

222

Dual myocardial single photon emission computed tomography (SPECT) using thallium-201 and I-123-?-methyl-i-pentadecanoic acid in patients with Duchenne's progressive muscular dystrophy  

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Dual single photon emission computed tomography (SPECT) was performed in 31 patients with Duchenne's progressive muscular dystrophy (DMD) using 123I-?-methyl pentadecanoic acid (BMIPP) for myocardial fatty acid metabolism and 201thallium (Tl)-chloride for myocardial perfusion. The left ventricle was divided into 9 segments, and accumulation of the radiotracers was assessed visually for each segment to calculate defect score for each tracer. There was some degree of decrease in myocardial accumulation of both tracers in all DMD patients. Reduced accumulation was most common at the apex (BMIPP: 67%, Tl: 63%), followed by the posterior wall, lateral wall, and anterior wall. On the other hand, reduced accumulation was less common at the septum. BMIPP showed a higher accumulation than Tl in all segments but the septum. When BMIPP defect score was larger than Tl defect score, BMIPP defect score tended to increase during 4 years follow-up (p Tl defect score revealed a slightscore > Tl defect score revealed a slight fibrosis or normal myocardium. It can be concluded that the dual SPECT myocardial scintigraphy using BMIPP and Tl provides accurate information about disease progression of the heart in patients with DMD by detecting abnormalities of the myocardial metabolism of each substance, thereby enabling the assessment of left ventricular function. (author)

223

Evaluation of non-uniform attenuation correction using simultaneous transmission and emission computed tomography. Basic analysis with myocardial phantom  

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Simultaneous transmission emission protocol (STEP), developed for the non-uniform attenuation correction of single photon emission computed tomography (SPECT) was evaluated using the cardiac phantom prepared with and without a myocardial wall defect. Emission computed tomography (ECT) of the cardiac phantom using 201Tl was acquired. Transmission data (TCT) were taken using a line source of 99mTc. Myocardial images with STEP method were superior in the homogeneity of intramyocardial radioactivity and spatial resolution to the conventional SPECT images. This is an excellent method because of the accurate matching position between TCT and ECT images and shortening the examination time by simultaneous data acquisition. It would be clinically useful for diagnosing various myocardial diseases. (author)

224

Diagnostic merits of current and potential applications of single photon and positron imaging: a perspective  

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A brief review of the limitations of medical radionuclide imaging techniques in competition with x-ray CAT scanning and ultrasound suggest that the emphasis in this are should be on measurement of the physiologic uptake of tracer materials. Tomography greatly improves the possibilities of quantitation of this uptake - examples using positron and single photon techniques are presented for 13NH3 and 201Tl in the heart

225

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

226

Evaluating the sensitivity and specificity of 201Tl SPECT in intracranial tumoral pathology  

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The aim of this study was to evaluate the sensitivity of SPECT with 201Tl in detecting the cerebral tumors. A hundred and forty nine explorations were carried out (107 SPECT in patients clinically suspected and/or cerebral tumor radiography, 42 SPECT in patients treated for cerebral tumor to evaluate the persistence of the tumoral tissue immediately post-operation, or the presence of a tumoral recurrence). The SPECTs were achieved 15 minutes after the IV injection of 185 MBq of 201Tl with a double head Elscint Helix HR camera with fan collimators. The reconstructions were obtained by retro-projection with a Metz 3.13 filter. As the brain normally do not capture 201Tl, any fixation of 201Tl was considered an positive examination. The final diagnosis was based either on the histology (n = 41) or on clinical evolution (n = 149). The pathologies recorded were: 33 glial tumors, 32 metastases (51 lesions), 14 meningiomas, 1 hypophyseal adenoma, 1 cranio-pharyngogioma, 1 malign lymphoma, 1 gr.4 neurinomas, 1 arachnoid cyst, 34 AVCs, 24 normal, 2 complete surgical extirpations, and 5 necroses after treatment. In our population the sensitivity of SPECT with 201Tl for the diagnosis of intracranial tumors was calculated to be 91.5% and the specificity, 98.5%. We have met a false positive (recent hemorrhagic AVC) and 7 false negatives (4 metastases of which 3 were under 1 cm and another largely necrotic, 3 patients presentinger largely necrotic, 3 patients presenting residual tumoral tissue immediately post-operation, presently in recurrence). These excellent results prove the utility of SPECT with 201Tl both for positive diagnosis of cerebral tumors and for evaluation of these tumors after treatment

227

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)

228

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

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To estimate the dose equivalent (H{sub 1cm}) of a person who may come into close contact with patients (pts) exposed to {sup 201}Tl 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 {sup 201}TlCl. 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 H{sub 1cm} rate of 18.37 {mu}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 calculated effective half-life was 63.0 h. H{sub 1cm}{sup s} were 891, 196, 77 and 42 {mu}Sv/w per 74 MBq at distances of 0.05, 0.5, 1.0 and 1.5 m, respectively. These H{sub 1cm}{sup s} correspond to 84% of the total H{sub 1cm}{sup s} ({mu}Sv/{infinity}h). The family of a patient given {sup 201}Tl was one-third of the total H{sub 1cm}{sup s} at 0.05 m, the dose did not exceed the dose limit described in recommendations-1990 of ICRP. 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 H{sub 1cm}{sup s} at 0.5 m, these doses were the result of contact with 17 {sup 201}Tl pts and 257 {sup 201}Tl pts for one year. The dose of pt in the same room as pts given {sup 201}Tl were 42 {mu}Sv/w at 1.5 m; this dose did not exceed his dose limit of 100 {mu}Sv/w. These results do not suggest that radiation protection is necessary when exposed to a pt given {sup 201}Tl, but in the case of close contact with many {sup 201}Tl pts, it would be necessary when the radiation dose exceeds the limit. (author).

Ejiri, Kazutaka; Orito, Takeo [Fujita Health Univ., Toyoake, Aichi (Japan). School of Health Science; Koga, Sukehiko

1995-06-01

229

Scintigraphy of the myocardium with the use of 201Tl chloride  

International Nuclear Information System (INIS)

On the base of 337 examinations, conducted in 201 patients with cardiovascular diseases and in 16 healthy people, methodic aspects of myocardium scintigraphy with 201Tl chloride are specified, criteria of scintigram processing and interpretation being developed. It is shown that scintigraphy after intravenous injection of 201Tl is a highly informative method of the evaluation of myocardium perfusion state, permitting to find myocardium hypertrophy, left cardial ventricle dilatation and to determine the presence and localization of injured myocardium perfusion zones. It is established that adequate interpretation of the examination results is possible when conducting myocardium scintigraphy in 3 projections with subsequent computer processing

230

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)

231

201Tl /99mTc Subtraction Scan in the Diagnosis of Hyperparathyroidism  

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201Tl /99mTc pertechnetate subtraction scintigraphy of the parathyroid gland performed in a study of 8 patients with clinical and biochemical evidence of hyperparathyroidism for diagnosis and localization of the lesion prior to surgery. 6 cases of parathyroid adenomas were accurately localized and 2 cases of diffuse hyperplasia associated with chronic renal failure(CRF) and multiple endocrine neoplasia(MEN) type I. 201Tl /99mTc pertechnetate scan was useful for patients with hyperparathyroidism, especially in definite localization preoperatively.

232

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

233

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

International Nuclear Information System (INIS)

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)

234

Studies on portal systemic circulation by oral administration of 201Tl enclosed enteric coated capsule  

International Nuclear Information System (INIS)

Thallium-201 enclosed enteric coated capsule was prepared and administered orally to evaluate portal systemic circulation in 11 control subjects and 31 patients with various liver diseases by investigating scintigraphic appearance and the heart-to-liver uptake ratio (H/L ratio). In 10 patients with liver cirrhosis and one with chronic hepatitis, the results of H/L ratio were compared to those obtained by 201Tl per-rectal administration. 1. It was fundamentally confirmed that 201Tl enclosed enteric coated capsule was not broken down in the artificial gastric juice, but nearly completely melted 15 minutes after soaking in the artificial intestinal juice. 2. Clinical study was successfully completed in 36 out of 42 cases (86 %). Unsuccessful cases were found in 2 with capsule collapse in the stomach and 4 with its poor moving to the duodenum. 3. In control subjects the liver was clearly visualized and the mean value of H/L ratio was 0.32 which is lower than that of 201Tl per-rectal administration previously reported. H/L ratio in patients with chronic and acute hepatitis was nearly equal to that in control subjects. H/L ratio in patients with liver cirrhosis was slightly higher than that in control subjects, but there was no significant difference between them. In cases with esophageal varices, H/L ratio was not so high compared to that in control subjects. Out of 7 patients showing high H/L ratio more than 0.8 in 201Tl per-rectal administration, only one showed similar high ratio (1.07) in oral administration of 201Tl enclosed enteric coated capsule. In this case the shunting from superior mesenteric vein to inferior vena cava connection was confirmed. From these results, it was considered that the shunting volume of superior mesenteric vein through esophageal varices is small. 4. A possibility of a new administration of radioisotope with enteric coated capsule was emphasized. (author)

235

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  

International Nuclear Information System (INIS)

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 (P201Tl 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.)

236

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.)

237

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

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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

238

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

239

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

240

Contamination and radiation exposure from 201Tl in patients undergoing dialysis after a nuclear medicine study  

International Nuclear Information System (INIS)

Our institution is a major kidney research and transplant center. Hemodialysis patients that are scheduled for renal transplant are given a 201Tl stress test. Possible radiation exposure and contamination are of concern to attending personnel. We investigated this situation and found measurable activity in the effluent of patients receiving dialysis but no significant contamination of equipment. We determined that dialysis personnel received minimal radiation exposure

241

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

242

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)

243

Canine myocardial images by 201Thallium-Cl scintigraphy after coronary occlusion with and without reperfusion  

International Nuclear Information System (INIS)

Ligation of the coronary artery was performed in 30 dogs. Twelve dogs underwent reperfusion, and in all dogs 201Tl scintigraphy was performed in addition to examination with sodium fluorescein and pathohistological studies. Uptake of 201Tl was seen to decrease with the period of ligation. In long term ligation, the range of the 201Tl defect in the canine heart was narrow and differentiation was difficult, but pathohistologically remarkable thinning of the ventricular wall was observed. In 3 dogs which received preligation administration of 201Tl and heart resection 15 minutes after ligation, fluorescent defects were observed in the occluded areas but there was no noticeable decrease in 201Tl. In all reperfused cases, regardless of the reperfusion time, the decrease of 201Tl uptake disappeared within 6 hours and no defects were observed on sodium fluorescein studies after reperfusion. In cases reperfused after 12 hours-6 days ligation, decrease in 201Tl uptake and irreversible pathohistological changes were observed. These results showed that 201Tl uptake accurately reflected circulatory and myocardial disturbance. (author)

244

Estimation of the lung uptake ratio of 201Tl in cardiopulmonary diseases  

International Nuclear Information System (INIS)

On intravenous administration of 201TlCl (2-3mCi), the initial transit of it through the heart and lungs as well as subsequent uptake by the lung were recorded in the supine position using a scintillation camera coupling to a small digital computer. Leaving the patient in the same position the anterior image of perfusion lung scintigram with sup(99m)Tc-macroaggregated albumin or transmission scintigram with a point source of sup(99m)TcO4- taken. The radioactivity of total injected dosage (T) was calculated from the counts of the entire region on the initial transit of the tracer bolus through the heart and lungs, and counts per each pixel (E), total counts (L) and number of pixels (A) in the unilateral lung were calculated from the anterior image of 201Tl on which the isocount map of the perfusion lung scintigram or transmission one was superimposed. By these procedures, the uptake ratio of 201Tl per unilateral lung, the mean and each uptake ratio per pixel in the unilateral lung were calculated by L/T, L/T.A and E/T. Following results were obtained; 1) The mean value of the uptake ratio of it per unilateral lung in the right and left lung, were 1.5+-0.9%, 1.2+-0.6% in healthy lung; 3.2+-1.7%, 1.8+-1.0% in diffuse pulmonary diseases and 4.0+-1.6%, 2.5+-1.3% in cardiac diseases with left heart failure, respectively. 2) In the two groups using the perfusion lung scintigram and transmission one, the mean uptake rationd transmission one, the mean uptake ratio per pixel and number of pixels in the unilateral lung showed significant difference, but the uptake ratio per the unilateral lung did no significant difference. 3) These techniques are seemed to be useful for quantifying the lung uptake ratio of 201Tl on the lung scintigram with 201TlCl. (author)

245

Clinical studies on washout rate of thallium-201 myocardial single-photon emission computed tomography in patients with coronary artery disease  

International Nuclear Information System (INIS)

In order to clarify the influence of serial images, obtained by myocardial single-photon emission computed tomography (SPECT), in 19 normal subjects and 60 patients with coronary artery disease were analyzed. Myocardial short-axis images obtained by thallium-201 SPECT were divided into three segments (LAD, LCX and RCA segments). They were classified into four groups by the degree of coronary artery stenosis on the basis of coronary angiography, namely normal group (95 segments without stenosis), slight grade group (55 segments with 25-55% coronary artery stenosis), middle grade group (21 segments with 75% coronary artery stenosis) and high grade group (28 segments with 90-100% coronary artery stenosis). In the normal group, washout rates ranged from 27.8% to 63.1% and correlated well with maximal heart rate at bolus injection of thallium-201 (r=+0.74, p<0.01). Compared with 95% range of the values in normal group, the slight grade group was not able to be clearly separated from the normal group, and few of washout rates in groups with stenosis were abnormal when the maximal heart rates on exercise loading were lower than 100 per minute. On the contrary, in many of the high grade group, washout rates were lower than the 95% range when maximal heart rate on exercise loading reached more than 100 per minute. When maximal heart rates reached more than 140 per minute, in the middle grade group washout rates were also lower than the 95% range. These results show that exerci 95% range. These results show that exercise induced myocardial ischemia may not occur even in the segments with 75% coronary artery stenosis in the cases with the lower maximal heart rate than 140 per minute, and that a severe stenosis more than 90% may exist in the case with abnormal washout rate by the less amount of exercise loading. It is concluded that the maximal heart rate is an useful factor to evaluate myocardial ischemia and is able to separate a severe stenosis from a moderate one. (J.P.N.)

246

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.)

247

Transient left ventricular dysfunction in ischaemic myocardium after stress: comparative study with exercise and pharmacological stress gated myocardial single photon emission computed tomography.  

Science.gov (United States)

In ischaemic heart disease patients, transient left ventricular dysfunction is observed due to post-exercise stunning. The aim of this study was to determine whether transient left ventricular dysfunction could also be seen after short-acting pharmacological stress (adenosine triphosphate). A 1 day rest/stress gated myocardial single photon emission computed tomography was performed on 362 patients suspected of having ischaemic heart disease by exercise (n=199) or short-acting pharmacological stress (n=163). Left ventricular ejection fraction were estimated both at rest and stress. Based on perfusion findings, patients were subdivided into ischaemia, fixed defect and normal group. For the ischaemia and fixed defect group, left ventricular ejection fraction after stress was significantly decreased compared with the resting value by exercise stress (ischaemia group, 57.5+/-11.0 vs 60.4+/-10.4; fixed defect group, 47.7+/-16.7 vs 49.6+/-16.8; Pexercise (65.7+/-10.4 vs 66.8+/-10.2; P=NS) or pharmacological stress (63.0+/-11.7 vs 64.0+/-12.1; P=NS). It is concluded that a transient decrease in left ventricular ejection fraction after stress was observed following post-exercise, not following a short-acting pharmacological stress in patients showing perfusion abnormalities. Transient left ventricular dysfunction may be the result of post-exercise stunning, not from subendocardial hypoperfusion induced by short-acting pharmacological stress. PMID:12717073

Iwado, Y; Furuyama, H; Yoshinaga, K; Mabuchi, M; Ito, Y; Noriyasu, K; Kohya, T; Kitabatake, A; Tsukamoto, E; Tamaki, N

2003-05-01

248

Medium- to long-term prognostic impact of dipyridamole thallium-201 myocardial single-photon emission computed tomography in elderly patients  

International Nuclear Information System (INIS)

Dipyridamole thallium-201 single-photon emission computed tomography (SPECT) has not been extensively evaluated for risk stratification and the medium- to long-term prognostic value in elderly cardiac patients who are unable to exercise. The present study group comprised 210 consecutive patients aged at least 70 years with known or suspected coronary artery disease (CAD). The SPECT findings were classified as a reversible, fixed, or combined (reversible and fixed) defect. Of the 210 patients, 201 (77±5 years, 85 male) were successfully followed for 49±26 months. Thirteen (7%) patients had cardiac events: cardiac death (n=10), non-fatal myocardial infarction (n=1), or coronary artery bypass grafting (n=2). Cardiac events occurred in 3 of 112 patients with normal SPECT and in 10 of 89 patients with an abnormal scan (0.7%/year vs 2.8%/year, p=0.01). Stepwise Cox regression analysis revealed that the significant predictors of cardiac events were combined defects (relative risk 7.3) and the number of defect areas (relative risk 4.4). The predictive value of dipyridamole thallium-201 SPECT is maintained over 4 years in mixed populations of elderly CAD patients who are unable to exercise. (author)

249

Effect of thallium-201 blood levels on reversible myocardial defects.  

Science.gov (United States)

To determine if 201Tl plasma blood levels correlate with the presence of reversible myocardial defects during exercise testing, 14 patients with stable coronary artery disease underwent two separate exercise 201Tl stress tests. Between initial and delayed imaging, on one test the patients drank an instant breakfast drink (eating) and on the other they drank an equivalent volume of water as a control (H2O). Thallium-201 imaging was performed immediately postexercise, immediately after eating/H2O and 210 min after eating/H2O. Between initial and immediate post eating/H2O images 201Tl reversible defects occurred in 27/38 regions in the H2O test versus 15/38 regions in the eating test (p = 0.02). Over this early time period, plasma 201Tl activity was significantly higher in the H2O test than eating test (p less than 0.05). In conclusion, early reversal of 201Tl defects may, in part, be the result of higher plasma 201Tl activity early after initial postexercise 201Tl imaging. PMID:2661757

Nelson, C W; Wilson, R A; Angello, D A; Palac, R T

1989-07-01

250

Effect of thallium-201 blood levels on reversible myocardial defects  

Energy Technology Data Exchange (ETDEWEB)

To determine if /sup 201/Tl plasma blood levels correlate with the presence of reversible myocardial defects during exercise testing, 14 patients with stable coronary artery disease underwent two separate exercise /sup 201/Tl stress tests. Between initial and delayed imaging, on one test the patients drank an instant breakfast drink (eating) and on the other they drank an equivalent volume of water as a control (H/sub 2/O). Thallium-201 imaging was performed immediately postexercise, immediately after eating/H/sub 2/O and 210 min after eating/H/sub 2/O. Between initial and immediate post eating/H/sub 2/O images 201Tl reversible defects occurred in 27/38 regions in the H/sub 2/O test versus 15/38 regions in the eating test (p = 0.02). Over this early time period, plasma /sup 201/Tl activity was significantly higher in the H/sub 2/O test than eating test (p less than 0.05). In conclusion, early reversal of /sup 201/Tl defects may, in part, be the result of higher plasma /sup 201/Tl activity early after initial postexercise /sup 201/Tl imaging.

Nelson, C.W.; Wilson, R.A.; Angello, D.A.; Palac, R.T.

1989-07-01

251

Effect of thallium-201 blood levels on reversible myocardial defects  

International Nuclear Information System (INIS)

To determine if 201Tl plasma blood levels correlate with the presence of reversible myocardial defects during exercise testing, 14 patients with stable coronary artery disease underwent two separate exercise 201Tl stress tests. Between initial and delayed imaging, on one test the patients drank an instant breakfast drink (eating) and on the other they drank an equivalent volume of water as a control (H2O). Thallium-201 imaging was performed immediately postexercise, immediately after eating/H2O and 210 min after eating/H2O. Between initial and immediate post eating/H2O images 201Tl reversible defects occurred in 27/38 regions in the H2O test versus 15/38 regions in the eating test (p = 0.02). Over this early time period, plasma 201Tl activity was significantly higher in the H2O test than eating test (p less than 0.05). In conclusion, early reversal of 201Tl defects may, in part, be the result of higher plasma 201Tl activity early after initial postexercise 201Tl imaging

252

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

Energy Technology Data Exchange (ETDEWEB)

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

253

Attenuation correction by simultaneous emission-transmission myocardial single-photon emission tomography using a technetium-99m-labelled radiotracer: impact on diagnostic accuracy.  

Science.gov (United States)

Irregular photon attenuation may limit the diagnostic accuracy of myocardial single-photon emission tomography (SPET). The aim of this study was to quantify the potential benefit of attenuation correction by simultaneous emission and transmission imaging for the detection of coronary artery disease (CAD) of vessels supplying the inferoposterior wall segments. In 25 male patients with >/=50% stenoses of the right coronary artery and/or circumflex artery but without significant narrowing of the left anterior descending artery, stress studies using technetium-99m tetrofosmin (400 MBq) were carried out with and without attenuation correction. A dual-head camera with L-shaped detector positioning was equipped with two scanning gadolinium-153 line sources. Tomograms were reconstructed and quantified using circumferential count rate profiles of myocardial activity (two in each patient). The profiles were compared with the respective normal ranges obtained from a database of 25 male patients with a <10% likelihood of CAD. In patients without CAD, the maximal differences in count density of different wall segments were reduced from 29.0% in non-corrected (NC) studies to 9.5% in attenuation-corrected (AC) studies. In particular, the inferoposterior and septal wall segments were represented by significantly increased relative count densities after attenuation correction. The effects of attenuation correction proved independent of body mass. In patients with CAD, segmental count densities were abnormal in 84% of the NC studies and 100% of the AC studies. In single-vessel disease the stenotic vessel was identified in 66% of cases by NC studies and in 100% by AC studies. In AC studies, the extent and depth of defects exceeded those in NC studies. For the detection of CAD of the right coronary artery, the receiver operating characteristic (ROC) curves relating to the AC studies demonstrated improved discrimination capacity (P<0.05). ROC analysis of CAD detection yielded normalcy rates of 82% (NC) and 94% (AC) for the circumflex artery and 65% (NC) and 97% (AC) for the right coronary artery area at a sensitivity level of 95%. It is concluded that attenuation correction using the above system may enhance the diagnostic accuracy of myocardial SPET when inferoposterior wall segments are to be evaluated. PMID:9283102

Kluge, R; Sattler, B; Seese, A; Knapp, W H

1997-09-01

254

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

International Nuclear Information System (INIS)

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 ? 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 % T 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.)

255

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  

Energy Technology Data Exchange (ETDEWEB)

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 myocardial fatty acid metabolism BMIPP is useful for deciding culprit and viable lesions requiring coronary revascularization and evaluating therapeutical effects.

Nemoto, Shintaro; Oshitomi, Takashi; Endo, Masahiro; Koyanagi, Hitoshi [Tokyo Women`s Medical Coll. (Japan). Heart Inst. and Hospital; Harada, Masanori

1996-03-01

256

Measurement of regional wash out rate in stress thallium-201 myocardial scintigraphy using single photon emission computed tomography  

International Nuclear Information System (INIS)

Wash out rate (WR) of thallium-201 was analysed in 40 cases, including 10 normal cases and 30 cases with angiographically proved coronary artery disease (CAD), by using emission computed tomography (ECT). WR of normal segment (N) was 45.5+-7.8% (n=40), WR of nonischemic segment of CAD (IN) was 38.3+-10.2% (n=71), WR of ischemic segment (AP) was 28.6+-10.5% (n=64), WR of all myocardial infarctional segment (MI (all)) was 32.3+-12.2% (n=38), and WR of ischemic segment by coronary spasm (SP) was -5.3+-12.5% (n=7). WR of SP was remarkably lower than other segments and it was interesting that its value was minus. WR of infarctional segment (IS) without transient ischemia(TI) of one-vessel disease (1VD) or two-vessel disease (2VD)(MI (st)) was 39.6+-8.8% (n=21), WR of IS without TI of three-vessel disease (3VD)(MI (3)) was 26.2+-5.9% (n=9), and WR of IS with TI (MI (P)) was 19.9+-11.3% (n=8). WR of N was significantly higher than IN, AP, SP, MI(all), MI(st), MI(3), and MI(P) (p<0.001, p<0.001, p<0.001, p<0.001, p<0.005, p<0.001, p<0.001). WR of IN was significantly higher than AP, SP, MI(all), MI(3), and MI(P) (p<0.001, p<0.001, p<0.005, p<0.001, p<0.001). WR of AP was significantly higher than MI(P) and SP (p<0.025, p<0.001). WR of IN and MI(st), AP and MI(all), MI(3) were not significantly different. WR of IN was sometimes low especially when exercise was not adequate, therefore false positive might be observed. Differentiation between least severely diseased vessel of 3Vtween least severely diseased vessel of 3VD and normal vessel of 1VD or 2VD was not easy even when we used WR. We considered about mechanism of thallium wash out. (author)

257

Quantitative evaluation of myocardial single-photon emission tomographic imaging: application to the measurement of perfusion defect size and severity.  

Science.gov (United States)

A new method is described for precise quantitative analysis of the relative three-dimensional distribution of myocardial tracers. The system uses a 360 degrees elliptical sampling of radial slices to create activity profiles. These are then positioned onto a common centre at the same angular coordinates as the corresponding radial slice reconstruction planes to generate a two-dimensional polar summary display. Abnormal distribution is then identified by automatic comparison of the patient polar map with the threshold of a normal database defined on a pixel by pixel basis as the normal mean -2.5 SD. Our stress and rest databases currently comprise 34 and 24 studies for sestamibi and tetrofosmin respectively. The present method differs from currently available software in two major respects. First, radial slices are used rather than short-axis slices to minimize operator intervention and to allow quantitative evaluation of the left ventricle volume independent of the heart size and without truncation, in particular near the apex and at the base. This sampling scheme also results in a more homogeneous and sampling-independent partial volume effect. Secondly, quantitative analysis is improved by calculating perfusion defect severity, extent and size in a precise manner. Severity is evaluated relative to a standardized background measurement and to the mean normal value rather than to the threshold value. This parameter was underestimated up to a defect extent of 32 cm2 in our phantom studies. Calculation of defect extent takes into account the surface distortion resulting from planar projection by using pixel by pixel weighted factors but it is otherwise overestimated as a result of the limited resolution of the imaging system. Integrating defect severity and extent, our hypoperfusion index appeared to accurately estimate the true defect size in our phantom model (r=0.993). The reproducibility of analysis was 6.24% in phantom studies and 3.10% in patient studies including repeated acquisitions. Applied to a well-documented population of 80 patients, this method resulted in an 86% sensitivity and a 78% specificity for overall coronary artery disease detection with reference to the angiographic data. PMID:8929314

Benoit, T; Vivegnis, D; Foulon, J; Rigo, P

1996-12-01

258

Detecting viable myocardium and predicting functional improvement. Comparisons of positron emission tomography, rest-redistribution thallium-201 single-photon emission computed tomography (SPECT), exercise thallium-201 reinjection SPECT, I-123 BMIPP SPECT and dobutamine stress echocardiography  

International Nuclear Information System (INIS)

Low-dose dobutamine stress echocardiography (LDDE) has become a useful and safe method for identifying hibernating or stunned myocardium and for predicting improvement in wall motion after coronary revascularization. In the present study, fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), rest-redistribution thallium-201 (201Tl) single-photon emission computed tomography (RR-Tl SPECT), 123I-15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid (BMIPP) and LDDE were performed in 30 patients with acute myocardial infarction (AMI) at 10±3 days after the onset of AMI. Also, exercise 201Tl reinjection SPECT (RI-Tl SPECT) was performed at 14±2 days. Follow-up echocardiography was performed 5±3 months later in all patients after interventional therapy for the assessment of functional recovery. Of the 390 segments analyzed by echocardiography, 110 (28%) had abnormal wall motion. There were no significant differences between RR-Tl SPECT and LDDE in sensitivity, specificity, positive predictive value and negative predictive value using the ?2-test; however, in akinetic segments, there was a significant difference in sensitivity. Among FDG-PET, RI-Tl SPECT, BMIPP and LDDE, there were significant differences in 3 variables. In akinetic segments, LDDE is superior to RR-Tl SPECT in sensitivity and to FDG-PET in specificity. In hypokinetic segments, LDDE is superior to RI-Tl SPECT and BMIPP in sensitivity, and to FDG- and BMIPP in sensitivity, and to FDG-PET and BMIPP in specificity. LDDE could detect functional recovery of viable myocardium in the early period of AMI and can be performed easily and safely. (author)

259

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

International Nuclear Information System (INIS)

Gated single-photon emission computed tomography (SPECT) imaging of myocardium by 99mTc and 201Tl 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. Percent thickening of the myocardium was significantly higher in imaging by 99mTc-labelled tracers than in 201Tl. 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.)

260

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

261

Simultaneous dual myocardial imaging with iodine-123-?-methyl iodophenyl-pentadecanoic acid (BMIPP) and thallium-201 in patients with coronary heart disease  

International Nuclear Information System (INIS)

To assess the clinical value of simultaneous dual myocardial imaging with iodine-123-?-methyl-iodophenyl-pentadecanoic acid (123I-BMIPP) and thallium-201 (201TL), myocardial imaging was performed at rest and during execise in seven patients with coronary heart disease. When 123I-BMIPP and 201Tl images were compared, the initial exercise and resting images agreed 87% and 64%, respectively. In the initial resting images, the regional uptake of 123I-BMIPP was frequently less than that of 201Tl. The incidence of exercise-induced reversible defects by 201Tl in the Tl>BMIPP regions was significantly higher than that in the Tl=BMIPP regions (57% vs 4%, pBMIPP regions was also significantly higher than that in the Tl=BMIPP regions (91% vs 38%, pBMIPP) was found more frequently in regions with abnormal wall motion than in regions with normal wall motion (hypokinetic regions; 68%, severe hypokinetic or akinetic regions; 50%, vs normokinetic regions; 4%, p123I-BMIPP correlated closely with that of 201Tl in normal myocardium and the uptake of both 123I-BMIPP and 201Tl was severely reduced in myocardium with severe ischemia during exercise and prior infarction. These results indicate that dual myocardial imaging wi indicate that dual myocardial imaging with 123I-BMIPP and 201Tl may provide a unique means of identifying patients with metabolically disturbed myocardium, such as hibernating and stunned myocardium. (author)

262

Thallium-201 scintigraphy after acute myocardial infarction  

International Nuclear Information System (INIS)

55 patients with acute myocardial infarction were examined with thallium-201 scintigraphy before discharge from hospital. It is concluded that 201-Tl scintigraphy demonstrates the myocardial defects after the infarction and offers a possibility for rough estimation of the left ventricular dilatation, which seems to be related to short-term survival. (L.E.)

263

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)

264

Computer simulation of temperature distribution on a solid target for 201Tl production  

International Nuclear Information System (INIS)

Thallium-201 is of great interest in nuclear medicine for diagnostic purposes. It is produced by the 203Tl(p,3n)201Pb nuclear reaction. Since the target for 201Tl production is a solid target and the maximum beam current for the irradiation has a direct relation with its temperature surface, therefore, the control of temperature during the irradiation is essential. Designing a proper cooling system is one of the important and determining parameters in radionuclide production efficiency. Non-controlled temperature would cause melting and consequently loss of target materials that could be very costly especially when an isotopically enriched material is used. In this study, the heat transfer and temperature distribution on the target has been simulated based on a computational fluid dynamics (CDF) code for the thermal behavior of the target during the irradiation and under the different beam currents, cooling flow rates and target designing. The results on the routinely used target for the production of 201Tl in AMIRS, showed that there was a good linearity between proton beam currents (in the range of 100-350 ?A) and maximum temperature on the thallium target (345-458 K). The results also showed that the flow rate of the cooling water can be brought down (from routinely used 45 L/min) to 15 L/min without any risk of melting of target material. (authors)

265

SPECT imaging of hypertrophic cardiomyopathy with 201Tl and 123I-MIBG  

International Nuclear Information System (INIS)

Objective: The aim of this study is to clarify whether there are differences in sympathetic nerve activities between hypertrophied and non-hypertrophied myocardium in patients with hypertrophic cardiomyopathy (HCM). Methods:18 patients with HCM diagnosed with symptomatology and echocardiography and six normal subjects underwent two-dimensional and M-mode echocardiography, and SPECT with 201Tl and 123I-MIBG. The HCM group included 5 of apical type (APM), 7 of asymmetrical septal hypertrophy (ASH) and 6 of defused type (DPM). The average age of HCM group was (56.8 +-8.8) years, and normal group, 49.0 +- 5.4. Results: In 201Tl study, there was no difference between HCM and normal group. In 123I-MIBG study, HCM group showed low radioactivities compared with normal group (P123I-MIBG scanning in HCM group, APM and DPM type showed low activities in anterior (P123I-MIBG activities, mild hypertrophy group showed low activities as well as marked hypertrophy group did (P<0.01, P<0.01). Conclusion: The patients with HCM still can maintain normal blood flow in per unit myocardium, even though they showed decreased sympathetic nerve activities in the hypertrophied as well as non-hypertrophied myocardiumrophied myocardium

266

A noninvasive method for evaluating portal circulation by administration of 201Tl per rectum  

International Nuclear Information System (INIS)

A new method for evaluating portal systemic circulation by administration of 201Tl per rectum was performed in 13 control subjects and in 65 patients with various liver diseases. In normal controls, the liver was visualized on the 0--5-min image whereas the images of other organs such as the heart, spleen, and lungs were very poor. In patients with liver cirrhosis associated with portal-systemic shunt, and in many other patients with hepatocellular damage, the liver was not so clearly visualized, whereas radioactivity in other organs, especially the heart, became evident. The heart-to-liver uptake ratio at 20 min after administration (H/L ratio) was significantly higher in liver cirrhosis than in normals and patients with chronic hepatitis (p less than 0.001). The patients with esophageal varices showed a significantly higher H/L ratio compared with that in cirrhotic patients without esophageal varices (p less than 0.001). The H/L ratio also showed a significant difference (p less than 0.01) between Stage 1 and Stage 3 esophageal varices. Since there were many other patients with hepatocellular damage who had high H/L ratios similar to those in liver cirrhosis, the effect that hepatocellular damage has on the liver uptake of 201Tl is also considered. Our present data suggest that this noninvasive method seems to be useful in evaluating portal-to-systemic shunting

267

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.)

268

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

Energy Technology Data Exchange (ETDEWEB)

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 {beta}{sub 2}-microglobulin amyloid ({beta}{sub 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, {sup 67}Ga and {sup 201}Tl whole-body and SPET images were then acquired. If any {sup 67}Ga and/or {sup 201}Tl uptake was observed, a CT-guided biopsy was done. In those patients who had articular and/or peri-articular uptake of {sup 99m}Tc MDP, {sup 67}Ga and/or {sup 201}Tl and who were pathologically proven to have {beta}{sub 2}-MA, {sup 99m}Tc MDP, {sup 67}Ga and {sup 201}Tl 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 {sup 99m}Tc MDP uptake. Among these eight, six had intense {sup 99m}Tc MDP, {sup 67}Ga and {sup 201}Tl uptake in the articular and peri-articular regions before medication. Three months after the start of treatment, there were very marked decreases in uptake on both the {sup 67}Ga and {sup 201}Tl scans but less obvious changes in uptake of {sup 99m}Tc-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 {sup 67}Ga and {sup 201}Tl 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 {sup 99m}Tc-MDP whole-body bone scan can both detect active and pre-existing inactive deposits of {beta}{sub 2}-MA. {sup 67}Ga and {sup 201}Tl scans are helpful to differentiate active from inactive deposits of {beta}{sub 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.)

Yen Tzuchen; Tzen Kaiyuan [Dept. of Nuclear Medicine, Chang Gung Memorial Hospital, Taipei Medical Center and School of Medicine, Chang Gung University (Taiwan); Chen Kuosu; Tsai Chijuen [Dept. of Nephrology, Chang Gung Memorial Hospital at Keelung (Taiwan)

2000-01-01

269

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

Science.gov (United States)

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 beta 2-microglobulin amyloid (beta 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 beta 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 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 beta 2-MA. 67Ga and 201Tl scans are helpful to differentiate active from inactive deposits of beta 2-MA and to evaluate the therapeutic effect on these patients. SPET images are usually needed to distinguish articular and periarticular lesions from bone lesions. PMID:10654148

Yen, T C; Tzen, K Y; Chen, K S; Tsai, C J

2000-01-01

270

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)

271

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 100 cm 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 5 cm 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)

272

Sympathetic reinnervation in cardiac transplants: 123I-MIBG and 201Tl/99mTc-MIBI scintigraphy  

International Nuclear Information System (INIS)

The purpose was to evaluate cardiac sympathetic reinnervation and hemodynamic changes after orthotopic heart transplantation (TPL). We performed 24 serial or followup cardiac 123I-MIBG imaging and rest 201Tl/99mTc-MIBI dipyridamole stress gated myocardial perfusion SPECT (g-MPS) in 15 patients (M:F=10:5;mean ages=34.5±13.0 yr; idiopathic:rheumatic=14:1; one heart lung TPL)(10.80 ±11.88 (1-48) mo) after TPL 123I-MIBG imagings were performed in anterior position 15 minutes, 4 and 24 hours after i.v. injection of 148 MBq 123I MIBG. Image quantitation was based on the ratio of heart to mediastinal MIBG uptake (HMR) Compared to HMR on 15 min images (1.48 ± 0.28), neither four nor 24 hour delayed images (1.26 ± 0.23 vs. 1.06 ± 0.26: p<0.05, respectively, ANOVA) showed definite delayed localization of MIBG. 12 subjects with <13 (4.9 ±3.7) months after TPL had no visible 123I-MIBG uptake on early 15 min imaging however, 12 subjects with 13 to 48(28.6±12.8) months had visible cardiac 123I-MIBG uptake (HMR: 1.65±0.21 vs. 1.32±0.26; p=0.002). One-year followup 123I-MIBG scintigraphy in nine pts showed significantly increased HMR(1.40±0.31 to 1.61±0.16, p<0.05) but a plateau was reached at HMR value of 2.0, which was still lower than 3.0 in normal controls. Plasma NE was increased according to I-123 MIBG myocardial uptake. Annual G-MPS detected an allograft atherosclerosis in one pt and showed progressive normalization of tachycardia and significant deterioration of LVsignificant deterioration of LVEF and cardiac indices according to severity of rejection. To dipyridamole stress, transplant heats showed significant subnormal hemodynamic responses. Partial sympathetic late reinnervation can occur <1 year after TPL, and reached a plateau of two-third of normal value. G-MPS seems to be a useful screening test for the detection of allograft atherosclerosis and rejection

273

Clinical significance and changes of myocardial perfusion and myocardial metabolism after PTCA in patients with acute myocardial infarction  

International Nuclear Information System (INIS)

Objective: To investigate the changes of myocardial perfusion, fatty acid metabolism and glucose metabolism after percutaneous transluminal coronary angioplasty (PTCA) in patients with acute myocardial infarction (AMI), and evaluate its clinical implication. Methods: In 22 patients who underwent delayed PTCA after 4 weeks onset of AMI, dual SPECT with 201Tl, 123I-bata-methyl-iodophenyl pentadecanoic acid (BMIPP) and PET with 18F-fluorodeoxyglucose (FDG) were performed in acute phase (2 and 3 weeks) and chronic phase (5 months). Uptakes of 201Tl and 123I-BMIPP were evaluated by four defect score (DS), and the scores of two tracers were compared with each other in every segment. 201Tl/BMIPP mismatch equal DS of BMIPP minus DS of 201Tl. 18F-FDG uptake were determined quantitatively in the segments with hypoperfusion. Results: 18F-FDG uptake of segments with myocardial perfusion-fatty acid metabolism mismatch was higher significantly than that of segments with perfusion-fatty acid metabolism match in the acute phase [(76.5 ± 10.6)% and (45.8 ± 8.6)%, P201Tl/BMIPP mismatch (0.25 ± 0.42) and 18F-FDG uptake [(52.1 ± 8.1)%] in chronic phase were obviously lower than that in the acute phase [0.36 ± 0.51 and (72.8 ± 9.8)%]; in patients with restenosis, no signif patients with restenosis, no significant difference between acute phase and chronic phase in 201Tl/BMIPP mismatch and 18F-FDG uptake. Conclusion: Observation of the changes of myocardial perfusion-fatty acid metabolism and glucose metabolism have important value for the prediction of restenosis after PTCA in patients with AMI

274

Combined assessment of myocardial perfusion and function by ECG-gated myocardial perfusion single-photon emission computed tomography for the prediction of future cardiac events in patients with type 2 diabetes mellitus  

International Nuclear Information System (INIS)

The mid-term prognostic significance of electrocardiogram (ECG)-gated single-photon emission computed tomography (SPECT) remains unclear in Japanese patients with type 2 diabetes mellitus (DM). In the present study rates of future cardiac events (nonfatal acute myocardial infarction (AMI), cardiac death (CD) and severe heart failure (HF) requiring hospitalization) were compared in patients with and without DM. 1,810 patients (563 DM and 1,247 non-DM) we followed for a mean of 26.3±15.5 months. Summed stress score (SSS), summed difference score (SDS), poststress ejection fraction (EF) and resting end-diastolic volume (EDV) were calculated. In total, 20 cases of AMI (9 in DM (1.59%) and 11 in non-DM (0.88%)), 20 of CD (7 in DM patients (1.24%) and 13 in non-DM (1.04%)) and 54 of severe HF (31 in DM (5.5%) and 23 in non-DM (1.84%)) occurred. Univariate Cox analysis showed that, in DM patients, predictors of total cardiac events were poststress EF (Wald 60.4; P1c value (Wald 4.30; P<0.05). Multivariate Cox analysis showed that poststress EF (Wald 9.85; P<0.01) and SDS (Wald 6.19; P<0.01) were independent predictors of total cardiac events. Combined assessment of perfusion and function by ECG-gated SPECT may predict future cardiac events in type 2 DM patients. (author)

275

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  

Energy Technology Data Exchange (ETDEWEB)

Twenty-one patients with old myocardial infarction underwent repeated {sup 99m}Tc-tetrofosmin ({sup 99m}Tc) exercise/rest same day protocols with and without the administration of sublingual nitroglycerin (NTG) 5 min before the second injection of {sup 99m}Tc for rest SPECT. Twelve of these patients also underwent ordinary exercise/redistribution {sup 201}Tl SPECT. The control study protocol images showed decreased uptake of {sup 99m}Tc 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 {sup 99m}Tc 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 {sup 99m}Tc 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 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 {sup 99m}Tc-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.)

Miyanaga, Hajime; Kunieda, Yasufumi; Oguni, Atsuhiko; Kamitani, Tadaaki; Kawasaki, Shingo; Takahashi, Toru [Matsushita Memorial Hospital, Moriguchi, Osaka (Japan)

1999-03-01

276

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  

Energy Technology Data Exchange (ETDEWEB)

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

277

Single-photon imaging  

CERN Document Server

The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncoooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist´s view from different domains to the forthcoming “single-photon imaging” revolution. The various aspects of single-photon imaging are treated by internati...

Seitz, Peter

2011-01-01

278

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)

279

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

280

Single photon quantum cryptography  

CERN Document Server

We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 9500 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

Beveratos, A; Gacoin, T; Villing, A; Poizat, J P; Grangier, P; Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Villing, Andre; Poizat, Jean-Philippe; Grangier, Philippe

2002-01-01

281

Examination of the findings on 201Tl, 123I-BMIPP dual cardiac SPECT in acute phase of Kawasaki disease  

International Nuclear Information System (INIS)

In 42 cases with acute phase of Kawasaki disease (3-27 days since pathopoiesis), 201Tl, 123I-BMIPP dual cardiac SPECT was performed and the reduction of the isotope-uptake was macroscopically assessed. On cardiac SPECT, 28 of 42 cases (67%), and 19 of 30 cases (63%) who were normal on electrocardiogram, echocardiogram and blood CK levels showed abnormal images. In a part of cases showing abnormal cardiac SPECT, coronary arteriography was performed, and constrictive lesions with more than 25% were not observed. In acute phase of Kawasaki disease, the risk of cardiac complication was thought to be low. But these results suggest that there are cardiac complications detectable by 201Tl, 123I-BMIPP dual cardiac SPECT. This cardiac lesions were thought to be intramyocardinal microangiitis or abnormal coronary micro circulation cased by myocarditis associating microangiitis. (K.H.)

282

Excitation functions of reactions of production of radioisotopes 201Tl, 201Pb, 201Bi (experimental and theoretical data)  

International Nuclear Information System (INIS)

The results of calculations of charged particle induced reactions for the production of neutron deficient radioisotopes 201Tl, 201Pb, 201Bi and concomitant ones are discussed. The excitation functions for reactions 202Hg(p,xn), 197Au(a,xn), 203,205Tl(p,xn), 203,205Tl(d,xn), 203,205Tl(p,pxn), 204Pb(p,xn), 204Pb(p,p3n), 206Pb(p,6n), 206Pb(p,p5n), 207Pb(p,7n), 207Pb(p,p6n), 208Pb(p,xn) and 208Pb(p,p7n) are calculated on the base of statistical model in energy range up to 80 MeV. For the most reactions producing 201Tl the data on the calculated and practical yields under optimum conditions are given and the main admixture levels are pointed out. 30 refs., 9 figs

283

Leg {sup 201}Tl-SPECT in chronic exertional compartment syndrome; Tomoscintigraphie des jambes au thallium 201 dans le diagnostic du syndrome de loge chronique  

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Leg {sup 201}Tl-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 {sup 201}Tl-SPECT for patients with suspicion of compartment syndrome. Patients and methods: 51 leg {sup 201}Tl-SPECT exams were performed (exercise - and rest without reinjection) in 49 patients; 28 had compartment syndrome confirmed by pressure measurement. About 100 MBq of {sup 201}Tl 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 {sup 201}Tl level uptake between compartments with and without compartment syndrome and a significant correlation between muscular pressure measurement and rest level uptake. Conclusion: {sup 201}Tl-SPECT shows that only ischaemia does not explain compartment syndrome. 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)

Elkadri, N.; Slim, I.; Blondet, C.; Choquet, Ph.; Constantinesco, A. [Hopital Hautepierre, Service de Biophysique et Medecine Nucleaire, 67 - Strasbourg (France); Lecocq, J. [Hopital Hautepierre, Service de Medecine Physique et Readaptation, 67 - Strasbourg (France)

2004-06-01

284

Myocardial imaging with thallium-201 in the patients with coronary involvement after Kawasaki disease  

International Nuclear Information System (INIS)

Coronary cine-angiography (CAG) was performed in 290 cases with the history of Kawasaki disease, in whom 57 cases (19.6%) were found to have coronary involvements. In 42 out of these 57 cases, myocardial imaging with thallium-201 (201Tl) was performed, and abnormal findings were seen in 6 cases. Five of these 6 cases showed not only coronary aneurysms, but also coronary obstructive lesions on CAG, while the remaining case showed only coronary aneurysms. The decrease of the uptake of 201Tl by the myocardium appeared to be mainly due to the decrease of regional myocardial blood flow, especially in those cases with obstructive lesions. Myocardial imaging with 201Tl seems to be more sensitive than stress electrocardiography by treadmill to detect myocardial ischemia in the patients with coronary obstructive lesions, although it seems less sensitive than stress electrocardiography to detect coronary arterial stenosis. (author)

285

Single-photon Optomechanics  

OpenAIRE

Optomechanics experiments are rapidly approaching the regime where the radiation pressure of a single photon displaces the mechanical oscillator by more than its zero-point uncertainty. We show that in this limit the power spectrum has multiple sidebands and that the cavity response has several resonances in the resolved-sideband limit. Using master-equation simulations, we also study the crossover from the weak-coupling many-photon to the single-photon strong-coupling regim...

Nunnenkamp, A.; Borkje, K.; Girvin, S. M.

2011-01-01

286

Clinical application of gamma camera scintigraphy with 201Tl chloride in patients with nodular formations of the thyroid gland  

International Nuclear Information System (INIS)

The 201Tl chloride scanning extends considerably the diagnostic possibilities in cases with nodular formations of the thyroid gland. The positive Thallium scan should draw attention to the malignant character of the lesion. If it is not taken up by cold nodules would suggest benignant formations of the thyroid gland. Thallium chloride shows a high degree of selectivity for the primary carcinoma of the thyroid (82%). It is taken up both by differentiated and undifferentiated metastases of the cancer of the thyroid

287

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)

288

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

International Nuclear Information System (INIS)

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)

289

Value of 201Tl imaging in predicting therapeutic 131I uptake in patients with thyroglobulin-positive but 131I scan-negative differentiated thyroid carcinoma  

International Nuclear Information System (INIS)

Background: Serum thyroglobulin assay and 131Iodine (1311) whole body scan are considered complementary in detecting malignant thyroid tissue or metastases. A large number of patients, however, are encountered presenting with scan-negative, thyroglobulin-positive differentiated thyroid carcinoma posing a dilemma in therapeutic management. One of the first alternative scanning agents to be employed is 201Thallium (201Tl). Recent studies have demonstrated its usefulness in identifying lesions that are not visualized with traditional 131I whole body scan. It is not clear, however, whether 201Tl scan helps in the decision-making for subsequent 131I therapy. This study was conducted to determine if 201Tl scan can predict therapeutic 131I uptake and to define the clinical role of 201Tl scanning in these patients. Methods and results: A total of 12 patients (20-63 y/o), 5 males and 7 females, underwent surgery for differentiated thyroid cancer and all had serum thyroglobulin values above 10 ng/ml and normal TPO autoantibodies. Pre-therapy 131I scan using 111 MBq (3mCi) of 131I were obtained. As required for inclusion, all patients had negative pre-therapy scan and negative TPO autoantibody results and underwent 20lTl scanning within 3 weeks. All patients were given 131I therapy (3.7-5.5 GBq or 100-150 mCi) between one to two months after 201Tl scanning. Within a week after therapy, all patients underwent whole body 1311 scanning. 201Tl imaging demonstrated thyroid remnants iTl imaging demonstrated thyroid remnants in 9 out of 12 patients having positive 201Tl scan but negative pre-therapy 1311 scan. However, only 2 of the positive 201Tl scans showed 131I uptake post-therapy (positive predictive value of 20%). None of the subjects presented with a negative 201Tl scan and a positive post-therapy 131I scan. Conclusion: Our study suggests that evidence of remnants or metastases on 201Tl scanning may be an inappropriate basis for the decision to proceed with 131I therapy. The role of 20lTl imaging in this subset of patients may be limited to localization of metastases for surgical excision or localized radiation therapy. (authors)

290

Clinical significance of stress-induced ST segment changes in patients with previous myocardial infarction  

International Nuclear Information System (INIS)

To explain the clinical significance of stress(st)-induced ST-segment (ST) changes postinfarction, 93 patients with previous myocardial infarction (MI) were performed st-201Tl myocardial single photon emission computed tomography (SPECT) and compared ST changes with SPECT, coronary arteriographic and left ventriculographic findings. 30 out of 93 cases (32%) had ST depression, 20 (21.5%) had ST elevation, 9 (10%) had both ST depression and elevation and remaining 34 (36.5 %) had no significant ST changes. In single vessel disease, ST depression were noted in 29% (12/42), while in multivessel disease, 53% (27/51). 35 out of 39 cases (90%) with ST depression had transient perfusion defect but no apparent relation was noted between location of ST depression on ECG and region of transient perfusion defect in SPECT. All of 28 cases with ST elevation were noted in anterior MI cases, and 26 out of these showed severe LV wall motion abnormality in contrast left ventriculography and broad anterior permanent defect in SPECT. Only 15 cases (54%) showed slight redistribution. Thus, we conclude that in patients with previous MI, st-induced ST depression seems to reflect myocardial ischemia and ST elevation possibly related abnormal LV wall motion. (author)

291

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)

292

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.)

293

Thallium-201 myocardial scintigraphy  

International Nuclear Information System (INIS)

Eighty patients with coronary artery disease and 32 non-coronary patients were studied with the following results: 1) Sensitivity of exercise electrocardiography was 66% with coronary stenosis > 50% and 70% with stenosis > 75%. Specificity of this test was 72%. 2) Sensitivity of the thallium-201 (Tl-201) myocardial perfusion imaging was 77% with coronary stenosis > 50% and 80% with stenosis > 75%, and specificity was 80% and 96% with and without inclusion of cardiomyopathy and myocarditis, respectively. 3) Evaluation of exercise increments of Tl-201 fractional myocardial uptake and tomographic imaging using a 7-pinhole collimator further improve the sensitivity of myocardial perfusion scintigraphy. (author)

294

The correlation between 99mTc-MIBI uptake and MIB-1 as a nuclear proliferation marker in glioma - a comparative study with 201Tl  

International Nuclear Information System (INIS)

Technetium-99m methoxy-isobutylisonitrile (MIBI), like thallium-201 (201Tl), is a highly efficient agent for the diagnosis and monitoring of glioma tumors. Although 201Tl uptake is known to be partly associated with proliferative activity, little is known about the correlation between MIBI uptake and proliferation activity in gliomas. The current study was performed to assess the correlation between MIBI uptake and proliferative activities in gliomas, estimated by the monoclonal antibody to Ki-67 antigen (MIB-1) staining method. By comparing the results with those of 201Tl, we determined which tracer would be suitable for estimating proliferative activities. Twenty-four presurgical glioma patients (six with low-grade gliomas, five with anaplastic astrocytomas, and 13 with glioblastomas) were given MIBI and 201Tl SPECT. Early (10 min after injection) and delayed images (3 h after injection) were obtained for both MIBI and 201Tl scintigraphy. SPECT parameters, early ratio (ER), delayed ratio (DR), and retention index (RI) were obtained in both radiopharmaceuticals. All patients underwent subsequent surgical excision, and the specimens were immunostained for MIB-1. The proliferative activity was measured as a percentage positive nuclear area for MIB-1 (MI; MIB-1 index). To evaluate the relationship between the proliferative activity and SPECT parameters, we performed a correlation analysis. MI correlated with the MIBation analysis. MI correlated with the MIBI uptake ratio (r=0.75 for ER, and r=0.7 for DR). Both DR and RI of 201Tl also correlated with MI, but weakly (r=0.6 for DR, and r=0.59 for RI). There was no significant correlation between the MIB-1 index and the other parameters. MIBI-uptake parameters demonstrated a stronger positive correlation with the MIB-1 index than that of 201Tl. With the use of MIBI SPECT, we can estimate the proliferative activity of glioma non-invasively. (orig.)

295

Assessment of myocardial perfusion and metabolism for assessment of myocardial viability  

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Identifying preserved myocardial viability in the presence of severe regional left ventricular dysfunction is becoming increasingly more important for clinical decision-making to better select those patients with coronary artery disease who will benefit most from revascularization. {sup 201}Tl remains the most commonly employed radionuclide for detecting both ischemia and viability. A post-exercise defect showing complete or partial residtribution on delayed images implies transient ischemia and preserved viability with a 90% chance of exhibiting improved 2{sup 01}Tl uptake with repeat testing after coronary revascularization. Mild persistent defects with <50% {sup 201}Tl uptake on 4-hour redistribution images also imply viability with a 60- showing improved {sup 201}Tl uptake after repeat imaging following revascularization with concomitant enhancement of regional systolic function. In contrast, a severe persistent defect with <50% {sup 201}Tl uptake compared to peak to improved perfusion and corresponding improved function after revascularisation. detection of defect reversibility on {sup 201}Tl imaging is enhanced by `reinjection` of a second {sup 201}Tl dose after acquisition of redistribution images. Initial and 4-hour rest/redistribution imaging has proven most usefull for detection of viability in the resting state in patients with ischemic cardiomyopathy. The greater the extent of preoperative viability, the greater is the improvement in regional and global function after revascularisation. {sup 99}Tc sestamibi has also been demonstrated to be extracted by myocardial cells in proportion to regional blood flow in the presence of viable myocities. Although this agrnt does not redistribute after intravenous injection, its >50% uptake of the tracer implies viablility and predicts improved regional function after revascularisation. (Abstract Truncated)

Beller, G. [Univ. of Virginia. Health Sciences Center Charlottesville, Virginia (United States). Cardiovascular Division

1996-03-01

296

Attenuation correction improves the detection of viable myocardium by thallium-201 cardiac tomography in patients with previous myocardial infarction and left ventricular dysfunction  

International Nuclear Information System (INIS)

The aim of this study was to determine the influence of attenuation-corrected thallium-201 stress/redistribution/reinjection single-photon emission tomography (SPET) on the number of viable segments in patients with previous myocardial infarction and dysfunctional myocardium. Fifty-one patients with previous myocardial infarction and left ventricular dysfunction were included in the study. In all patients, 201Tl non-corrected (NC) and attenuation-corrected (AC) SPET was performed using a stress/redistribution/reinjection protocol followed by coronary angiography. A semiquantitative analysis was performed using polar maps for NC and AC stress, redistribution and reinjection short-axis and vertical long-axis (apex) slices. Severe (perfusion defect below 50%/maximal count rate: PD), mild and moderate persistent defects for redistribution and reinjection were evaluated for both NC and AC studies. A total of 1581 segments were evaluated by semiquantitative segmental analysis for both NC and AC studies for each redistribution and reinjection map. In the redistribution maps, NC revealed a total of 352 segments and AC a total of 222 segments with impaired perfusion below 50% of the maximal count rate (PD). The mean number of affected segments was 6.9±5.5 in the case of NC and 4.4±4.8 in the case of AC (P) and AC a total of 169 non-viable ssub>) and AC a total of 169 non-viable segments. The mean number of affected segments was 5.2±5.3 in the case of NC and 3.3±4.2 in the case of AC (P201Tl imaging without attenuation correction may underestimate the extent of tissue viability, which may contribute to the lower sensitivity compared to fluorine-18-fluorodeoxyglucose positron emission tomography, where attenuation correction is a routinely performed procedure. (orig.)

297

Dual-isotope myocardial imaging: feasibility, advantages and limitations. Preliminary report on 231 consecutive patients  

International Nuclear Information System (INIS)

Two hundred and thirty-one patients underwent dual-isotope myocardial imaging (rest thallium-201 followed by stress technetium-99m sestamibi). The feasibility of the procedure was excellent: camera scheduling flexibility was improved and the duration of the procedure was less than that of a classical stress-redistribution procedure. Interpretation of defects due to image attenuation was facilitated by the different attenuation properties of 201Tl and 99mTc-sestamibi in 11 of 19 patients. 201Tl cross-over on 99mTc was found to be 15% ± 3% with doses of 201Tl and 99mTc-sestamibi of 3 and 10 mCi, respectively, and 7% ± 2% with doses of 3 and 20 mCi. This protocol should preferentially be reserved for patients with a history of myocardial infarction and/or a basal left ventricular dysfunction, in whom assessment of myocardial viability is of major interest. (orig./MG)

298

Slowing down single photons  

Science.gov (United States)

Single photons emitted from a quantum dot can be slowed down using a hybrid semiconductor-atomic interface. Nika Akopian from Delft University of Technology in The Netherlands explained to Nature Photonics how this non-classical light storage system works.

2011-04-01

299

Characteristics of the myocardial SPECT images of 99mTc-MIBI and 99mTc-Teboroxime  

International Nuclear Information System (INIS)

Characteristics of the myocardial distribution of 99mTc-Teboroxime was compared with the myocardial distibution of 201Tl. We made summed myocardial images, in which central three short-axis SPECT slices were added. Rectagular region of interest (ROI) was set on each myocardial segment, and mean counts of each myocardial region was obtained using summed short-axis images. The ratio of inferior-to-anterior mean counts (I/A) was 0.69±0.20 in 99mTc-MIBI and 0.62±0.16 in 201Tl. The ratio of inferior-to-lateral mean counts was 0.70±0.18 and 0.65±0.13, respectively. Both ratios in 99mTc-MIBI were significantly higher than those in 201Tl (p201Tl to 929mTc-MIBI ratios of these two values were 1.11±0.17 (I/A) and 1.08±0.16 (I/L). The ratios of I/A and I/L of 99mTc-MIBI were about 10 percent higher than those of 201Tl. 99mTc-Teboroxime dynamic short-axis SPECT images of every three-minute were obtained. The ratios of counts in each wall were calculated similarly. After about 8 minutes, gradual increase in hepatic activity can be a cause of quatitative error in the assessment of SPECT images. We obtained the data with a human cardiac phantom. The myocardial phantom filled with 99mTc or 201Tl was placed in the mediastinal portion that is surrounded by the lung (saw dust) and vertebra (plastic bar). The ratio of I/A bra (plastic bar). The ratio of I/A was 0.79 and I/L was 0.85 in 201Tl. The I/A ratio was 0.93 and I/L was 0.97 in 99mTc. Both ratios in 99mTc were about 15 percent higher than those in 201Tl. When we assess images quantitatively using these new 99mTc-labeled myocardial agents, it is necessary to interpret the images taking account of the characteristics, because the radiopharmaceutical distribution of these new agents are different from that of 201Tl. (author)

300

The effect of scattering in simultaneous acquisitions of 99mTc and 201Tl. A fundamental study through phantom experiments  

International Nuclear Information System (INIS)

The simultaneous acquisition method in SPECT has some advantages, such as potentially doubling throughput in an examination and halving the acquisition time. However, interradionuclide scattering limits diagnostic accuracy. We evaluated 99mTc and 201Tl scattering using three energy windows. These windows were set at 71 keV with 15% window width for 201Tl images, at 90 keV with 10% window width for scatter images, and at 140 keV with 15% window width for 99mTc images. From phantom studies, the scatter correction coefficient, ?, was measured to be 1.07, while the crosstalk correction coefficient, ?, was measured to be 0.14. The corrected counts, a, in the 71 keV window for 201Tl image and the corrected counts, b, in the 140 keV window for 99mTc image were given as follows: a=A-?C, b=B-?a where A is the raw counts in the 71 keV window, B the raw counts in the 140 keV window, and C the raw counts in the 90 keV window. Simultaneous dual-radionuclide 99mTc/201Tl scintigraphy is feasible using 99mTc scatter and 201Tl crosstalk correction coefficients. (author)

301

Prognostic value of Tl-201 stress scintigraphy in patients with inferior myocardial infarction  

International Nuclear Information System (INIS)

The results demonstrate that 201Tl imaging is superior to stress ECG in predicting additional reversible ischemia in patients with previous inferior myocardial infarction. The predictive accuracy for involvement of the LAD was significantly higher (71% vs 44%) than stress ECG. The predictive accuracy for involvement of the circumflex artery was very low (25%). An additional advantage is the high specificity of 201Tl imaging. In some patients abnormal ST-depressions in the anterior chest leads of the stress ECG can reflect collateral circulation to the occluded right coronary artery and not LAD diseases. These results emphasize the prognostic implications of Tl imaging in patients with previous inferior myocardial infarction

302

ST-vector orientation and location of myocardial perfusion defects during exercise  

International Nuclear Information System (INIS)

In 34 patients with chest pain the spatial orientation of the ST-vectors in the exercise electrocardiogramm 30 and 80 msec after the end of QRS were compared with the location of exercise induced local defects of myocardial uptake of 201Tl. The following results were obtained: 1. The sensitivity and specifity of myocardial perfusion imaging after exercise were the same as those of exercise electrocardiograms; 2. No relation could be observed beween the location of reduced 201Tl uptake during exercise and the spatial orientation of the ST-vectors. (orig.)

303

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

304

Single-photon optomechanics.  

Science.gov (United States)

Optomechanics experiments are rapidly approaching the regime where the radiation pressure of a single photon displaces the mechanical oscillator by more than its zero-point uncertainty. We show that in this limit the power spectrum has multiple sidebands and that the cavity response has several resonances in the resolved-sideband limit. Using master-equation simulations, we also study the crossover from the weak-coupling many-photon to the single-photon strong-coupling regime. Finally, we find non-Gaussian steady states of the mechanical oscillator when multiphoton transitions are resonant. Our study provides the tools to detect and take advantage of this novel regime of optomechanics. PMID:21902323

Nunnenkamp, A; Børkje, K; Girvin, S M

2011-08-01

305

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

Energy Technology Data Exchange (ETDEWEB)

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

306

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)

307

Identification of single photons  

International Nuclear Information System (INIS)

Several processes are expected to yield high energy single photons at the LHC. Basically they fall into two categories: a) Resonances decaying into one or more photons. b) Standard QCD processes yielding a photon or photon pair continuum. In both cases the background comes mainly from ?0's and eta's decaying into two photons. The problem then reduces to determining whether a shower observed in an electromagnetic calorimeter originates from one or two photons. There are two ways to go about this. (orig.)

308

Proprieties of quantitative evaluation of defect size by myocardial SPECT  

International Nuclear Information System (INIS)

The accuracy to quantify the size and the extent of Thallium-201 (Tl) uptake of defect zone by Tl single photon emission computed tomogram (SPECT) was evaluated, using myocardial phantom. Long-axis SPECT image was devided into 6 slices from apex to base, and radians were projected from the center to define 32 myocardial secters, 11.25 degrees each. Then the maximum count in each secter was plotted on each radian (maximum count circumferential profile analysis:mcCPA), and was normalized to the maximum count for the whole heart (%Tl-uptake). In this way, circumferential profile curve was obtained, and normal value in each secter of myocardial phantom with defects was analysed and the ratio of segments, %Tl-uptake of which was below the normal value, was defined as % defect volume (%DV). The difference between the value of %Tl-uptake of defect zone and the normal value was difined as defect severity, and the average of defect severity was defined as mean defect severity (mDS). We prepared myocardial phantoms with a variety of area of defect, and with a variety of thickness of defect, and acquired these SPECT images. %DV and mDS were calculated from those images and compared with real area and thickess of defect. In the phantom with given thickness of defect, %DV was closely correlated to area of defect (r > 0.976), but also correlated to thickness of defect. In the phantom with given area of defect, mDS was closely correlated to thickness of defect (r = 0.988), and also thickness of defect (r = 0.988), and also correlated to area of defect. In conclusion, %DV and mDS were good indices of the defect size and the extent of Tl-uptake respectively, but it is necessary to consider their influence on each other. (author)

309

Comparative value and limitations of thallium-201 and technetium-99m-pyrophosphate myocardial imaging in acute myocardial infarction  

International Nuclear Information System (INIS)

Comparing the results of 201Tl and sup(99m)Tc-pyrophosphate myocardial imaging in patients with acute myocardial infarction, it is evident that both imaging techniques provide different information and each has its own advantages and disadvantages. For the practical application in the coronary care unit, it is essential to realize that each method yields its best results at different time intervals after onset of myocardial infarction. (Auth.)

310

The usefulness of dipyridamole thallium-201 single photon emission computed tomography for predicting perioperative cardiac events in patients undergoing non-cardiac vascular surgery  

International Nuclear Information System (INIS)

The aim of this study was to evaluate the usefulness of dipyridamole Tl-201 myocardium single photon emission computed tomography (201Tl-SPECT) for predicting perioperative cardiac events in patients with arteriosclerosis obliterans (ASO) and abdominal aortic aneurysm (AAA) undergoing non-cardiac vascular surgery. Preoperative dipyridamole 201Tl-SPECT imaging in association with clinical risk assessment was performed in 224 consecutive patients (97 ASO and 127 AAA). The patients were classified into three groups, including low-risk (n=173, 77%), intermediate-risk (n=39, 18%), and high-risk (n=12, 5%) groups according to the clinical risk stratification. The prevalence of reversible Tl-201 defect was significantly higher in the high-risk group than that in the low-risk group (83% vs. 14%, p201Tl-SPECT was the only variable to predict perioperative cardiac events by a stepwise logistic regression analysis (odds ratio 7.0, 95% confidence interval 1.7-28.0, p=0.007). It was also a significant predictor of perioperative cardiac events in a subgroup of low riive cardiac events in a subgroup of low risk patients (odds ratio 11.6, 95% confidence interval 2.3-57.4, p=0.004). The sensitivity and specificity of the reversible defect for predicting perioperative cardiac events were 55.6% and 84.8% in all operated patients, and 57.1% and 89.7% in low risk patients, respectively. The preoperative dipyridamole 201Tl-SPECT was useful for predicting perioperative cardiac events in patients with vascular diseases, even in patients identified as having a low risk based on the clinical risk assessment. (author)

311

Clinical evaluation of left ventricular wall thickness by combined technique with gated planer 201Tl image and gated cardiac pool image  

International Nuclear Information System (INIS)

To evaluate the left ventricular (LV) wall thickness, combined technique with gated planer 201-Thallium image and gated cardiac pool image was applied to 6 patients with hypertrophic cardiomyopathy (HCM) and 4 patients with secondary hypertrophy due to hypertension (HHD) proven by electrocardiography and ultrasonic-echocardiography. Scintigraphic pattern of hypertrophy on reconstructed planer 201Tl image showed diffuse or asymmetrical apical hypertrophy in HHD, asymmetrical septal hypertrophy in HCM. It was very interesting that abnormal perfusion was shown in 201Tl image, despite symmetrical hypertrophy in echocardiography. This techniques provided useful information for evaluating the LV wall thickness and cardiac performance. (author)

312

Standardization of 201Tl and 55Fe radionuclides in a 4 (PC)-NaI(Tl) coincidence system  

International Nuclear Information System (INIS)

In the present work the procedure for the standardization of radionuclides using the 4?(PC)-NaI(Tl) coincidence system was developed. The radionuclides selected were 201Tl, used in nuclear medicine, and 55Fe primary standard source, used for x-ray spectrometers calibration. The 4?(PC)-NaI(Tl) is composed of a 4 proportional counter operated at 0.1MPa coupled to two NaI(Tl) crystals. The 201Tl decays by electron capture process followed by a prompt gamma-ray. The disintegration rate was determined by extrapolation technique using two methods: electronic discrimination and external absorbers. The radioactive sources were prepared in a 20 ?g cm-2 thick Collodion film. The conventional electronic system was used. The observed events were registered by the TAC method. The 55Fe decays by electron capture process to the ground state of 55Mn, emitting x rays with around 6 keV. The standardization was obtained by the tracing method. This technique was applied using two radionuclides, which decay by electron capture process followed by a prompt gamma-ray, namely 51Cr and 54Mn, as tracers. Measurements with 1 and 2 aluminum foils, each 150 g cm-2 thick were carried out. The activity was obtained by extrapolation for zero thickness Al foil. The uncertainties were treated by means of matrix covariance methodology and takes into account all correlations involved. (author)

313

Attenuation-corrected thallium-201 single-photon emission tomography using a gadolinium-153 moving line source: clinical value and the impact of attenuation correction on the extent and severity of perfusion abnormalities.  

Science.gov (United States)

The aim of the study was to test the clinical value of attenuation-corrected (AC) thallium-201 single-photon emission tomography using a moving gadolinium-153 line source in a group of patients in whom coronary angiography was planned because of clinically suspected coronary artery disease (CAD). Furthermore, we wanted to test the impact of AC on assessment of the extent and severity of perfusion abnormalities. A total of 107 patients planned to undergo coronary angiography were included in the study. In each patient, AC and NC (non-corrected) 201Tl SPET was performed. AC and NC images were evaluated visually as well as by a 31-segment semiquantitative analysis and the findings were correlated with angiographic results. Patients were assigned to two groups: group A with angina and no previous cardiac infarction or intervention and group B with known CAD because of previous myocardial infarction or intervention. With visual analysis, NC revealed a sensitivity of 88.9% in group A and 74.3% in group B, compared to 94.4% in group A and 94.3% in group B with AC. Specificity for NC was calculated to be 68.7% for group A and 91.3% for group B. AC demonstrated significantly higher specificity of 83.9% and 100% respectively. This effect was particularly demonstrated for males and bicycle workload. The extent and severity of perfusion abnormalities were significantly influenced by the use of AC, in that significantly fewer abnormal and less severely abnormal segments were demonstrated in the segmental analysis as compared to NC; this was especially true for the vascular territory of the left anterior descending artery and the right coronary artery. It is concluded that AC with a moving line source is feasible in patients with all degrees of probability of CAD. AC has a significant impact on the assessment of the severity and extent of myocardial ischaemia, especially in the posterior and septal wall. PMID:9580853

Gallowitsch, H J; Sykora, J; Mikosch, P; Kresnik, E; Unterweger, O; Molnar, M; Grimm, G; Lind, P

1998-03-01

314

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

Energy Technology Data Exchange (ETDEWEB)

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

315

Quantitative analysis of myocardial ischaemia on end-diastolic thallium 201 perfusion images  

International Nuclear Information System (INIS)

ECG gating of images with 201Tl may improve the representation of myocardial perfusion by allowing isolation of the end-diastolic (ED) portion of the cardiac cycle. To characterize this phenomenon, circumferential distribution profiles for ED and conventional total-cycle images (TC) with 201Tl were analysed after summing ECG-gated acquisitions; redistribution was defined as net washin of 201Tl for specific myocardial segments visualized on the left anterior oblique images. Scintigraphic data were compared with the presence of coronary stenoses in 150 patients. ED images had relatively less activity in the inferoseptal and inferoapical region than TC profiles. The ED mode of washout analysis provided more frequent confirmation of visually suggested redistribution than did the TC mode (84% incidence of net wash-in for ED, 69% for TC). ED analysis showed a higher incidence of net 201Tl washin in relation to critical circumflex and left anterior descending artery lesions but yielded a similar overall performance to TC analysis in distinguishing patients with diseased coronary arteries from normal subjects. This, in selected cases, analysis of ED images could assist in confirming 201Tl redistribution. (orig.)

316

Modified triple energy window method for scatter correction. Application to dual energy acquisition in myocardial SPECT  

Energy Technology Data Exchange (ETDEWEB)

To correct Compton scatter in three-head SPECT systems without any software for Triple Energy Window (TEW) correction, a modified-TEW (M-TEW) method was devised. The data of two subwindows located at both sides of the main window were acquired separately. In phantom studies using {sup 201}Tl and {sup 99m}Tc, the most adequate width of the subwindows was determined to be 5 keV by NEMA method. Applying the M-TEW method to dual-energy acquisition, both cross talks from {sup 201}Tl to {sup 99m}Tc window (2.8-19.7%) and {sup 99m}Tc to {sup 201}Tl window (4.7-31.8%) were deducted. The M-TEW method could estimate approximately (43.9-62.4%) of scatter in {sup 201}Tl main window and (20.9-32.4%) of scatter in {sup 99m}Tc window respectively. In a clinical case, the M-TEW method could improve the contrast of myocardium in exercise and rest myocardial SPECT with {sup 201}Tl/{sup 99m}Tc-tetrofosmin dual energy acquisition. Scatter correction by the M-TEW method in a three-head SPECT system was possibly performed without special software for the TEW correction. The method also improved the quality of imaging in dual isotope myocardial scintigraphy. (author)

Nagamachi, Shigeki; Jinnouchi, Seishi; Shimoshinbara, Shigeru; Maeno, Masakazu; Ohnishi, Takashi; Flores, L.G. II; Nakahara, Hiroshi; Futami, Shigemi; Tamura, Syozo [Miyazaki Medical Coll., Kiyotake (Japan)

1999-03-01

317

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  

Energy Technology Data Exchange (ETDEWEB)

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

318

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

Energy Technology Data Exchange (ETDEWEB)

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

319

Single photons on demand  

International Nuclear Information System (INIS)

Quantum cryptography and information processing are set to benefit from developments in novel light sources that can emit photons one by one. Quantum mechanics has gained a reputation for making counter-intuitive predictions. But we rarely get the chance to witness these effects directly because, being humans, we are simply too big. Take light, for example. The light sources that are familiar to us, such as those used in lighting and imaging or in CD and DVD players, are so huge that they emit billions and billions of photons. But what if there was a light source that emitted just one photon at a time? Over the past few years, new types of light source that are able to emit photons one by one have been emerging from laboratories around the world. Pulses of light composed of a single photon correspond to power flows in the femtowatt range - a million billion times less than that of a table lamp. The driving force behind the development of these single-photon sources is a range of novel applications that take advantage of the quantum nature of light. Quantum states of superposed and entangled photons could lead the way to guaranteed-secure communication, to information processing with unprecedented speed and efficiency, and to new schemes for quantum teleportation. (U.K.)

320

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)

321

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 the myocardial uptake divided by the activity of total injected dose. Its mean value were 3.49 +- 0.45% in normals, 2.84 +- 0.47% in myocardial infarction and 3.00 +- 0.37% in angina pectoris, respectively, which showed significant low values in the latter two groups. MBF (ml/min/m2) = MBF/CO (%) x Cardiac index (CI). The mean value of MBF was iac index (CI). The mean value of MBF was 100.4 +- 12.7 ml/min/m2 in normals, 80.5 +- 21.1 in myocardial infarction and 77.3 +- 15.4 in angina pectoris, respectively, showing also significant low values in the latter two groups. Especially, MBF was most significant low in the groups of myocardial infarction with high serum CPK values. (author)

322

Cumulative cross-sections of 200Tl, 201Tl, 202Tl production in 660 MeV proton-induced spallation of lead and bismuth  

International Nuclear Information System (INIS)

The cumulative cross-sections of 200Tl, 201Tl and 202Tl production from lead and bismuth targets irradiated with 660 MeV protons are defined and a procedure for radiochemical separation of thallium from these targets is suggested. (author)

323

Evaluation of portal circulation in rats by rectal administration of 201Tl followed by intrasplenic injection of 51Cr-labeled microspheres  

International Nuclear Information System (INIS)

The heart-to-liver (H/L) uptake ratio in rats was determined 8 min after the rectal administration of 201Tl. Apart from normal controls, three groups of rats were examined; these were composed of animals with induced (1)acute hepatic damage, (2) liver cirrhosis, and (3) partial portal-vein ligation. After the rectal administration of 201Tl, 51Cr-labeled microspheres were injected into the spleen. The radioactivity of the removed liver, lungs, and heart was determined in a gamma-well scintillation counter, and the radioactivity of 201Tl and the 51Cr-labeled microspheres was separately calculated using simultaneous equations derived from the results of a preliminary experiment. The H/L ratios (201Tl) in the normal controls and the animals with acute hepatic damage were not significantly different; however, there was a positive correlation (P51Cr microspheres) in three groups, i.e., normal controls, liver cirrhosis, and partial portal-vein ligation. (orig.)

324

Quantification of the right ventricular wall using stress myocardial emission computed tomography with thallium-201 in normal subjects  

International Nuclear Information System (INIS)

Although many studies of quantitative analysis of left ventricular myocardial wall (LVMW) have been reported using stress thallium-201 (Tl-201), few reports of right ventricular myocardial wall (RVMW) have been estimated. In this study we determined whether single photon emission computed tomography (SPECT) with Tl-201 could accurately define normal range of RVMW in normal subjects. Twelve persons who have no valvular disease, nor coronary artery disease were included in this study. Stress SPECT study was reconstructed to make a short axial images of ventricles. RVMW and LVMW were flagged by mamual. Each ventricle was divided into 36 parts at every 10 degree. Relative activity counts in each ventricle were calculated as a percent counts of maximum counts in left ventricle. The normal range of RVMW with stress SPECT was as follows: anterior wall (33.2 +- 11.4 %, mean +- 2 standard deviation, -62.7 +- 18.4 %), free wall (30.1 +- 12.4 % - 38.5 +- 8.8 %), inferior wall (40.4 +- 7.8 % - 60.0 +- 21.4 %), septal wall (65.2 +- 17.2 % - 71.1 +- 14.2 %). Above the results, SPECT with Tl-201 can accurately define the normal range of RVMW, and this method is usefull to quantify the degree of ischemia and hypertrophy in RVMW. (author)

325

Sympathetic reinnervation in cardiac transplants: {sup 123}I-MIBG and {sup 201}Tl/{sup 99m}Tc-MIBI scintigraphy  

Energy Technology Data Exchange (ETDEWEB)

The purpose was to evaluate cardiac sympathetic reinnervation and hemodynamic changes after orthotopic heart transplantation (TPL). We performed 24 serial or followup cardiac 123I-MIBG imaging and rest 201Tl/99mTc-MIBI dipyridamole stress gated myocardial perfusion SPECT (g-MPS) in 15 patients (M:F=10:5;mean ages=34.5{+-}13.0 yr; idiopathic:rheumatic=14:1; one heart lung TPL)(10.80 {+-}11.88 (1-48) mo) after TPL 123I-MIBG imagings were performed in anterior position 15 minutes, 4 and 24 hours after i.v. injection of 148 MBq 123I MIBG. Image quantitation was based on the ratio of heart to mediastinal MIBG uptake (HMR) Compared to HMR on 15 min images (1.48 {+-} 0.28), neither four nor 24 hour delayed images (1.26 {+-} 0.23 vs. 1.06 {+-} 0.26: p<0.05, respectively, ANOVA) showed definite delayed localization of MIBG. 12 subjects with <13 (4.9 {+-}3.7) months after TPL had no visible 123I-MIBG uptake on early 15 min imaging however, 12 subjects with 13 to 48(28.6{+-}12.8) months had visible cardiac 123I-MIBG uptake (HMR: 1.65{+-}0.21 vs. 1.32{+-}0.26; p=0.002). One-year followup 123I-MIBG scintigraphy in nine pts showed significantly increased HMR(1.40{+-}0.31 to 1.61{+-}0.16, p<0.05) but a plateau was reached at HMR value of 2.0, which was still lower than 3.0 in normal controls. Plasma NE was increased according to I-123 MIBG myocardial uptake. Annual G-MPS detected an allograft atherosclerosis in one pt and showed progressive normalization of tachycardia and significant deterioration of LVEF and cardiac indices according to severity of rejection. To dipyridamole stress, transplant heats showed significant subnormal hemodynamic responses. Partial sympathetic late reinnervation can occur <1 year after TPL, and reached a plateau of two-third of normal value. G-MPS seems to be a useful screening test for the detection of allograft atherosclerosis and rejection.

Kim, J. H.; Oh, S. J.; Son, M. S.; Son, J. W.; Choi, I. S.; Shin, E. K.; Park, C. H. [Gachon Medical School, Gil Heart Cener, Inchon (Korea, Republic of)

2000-07-01

326

Attenuation correction by simultaneous emission-transmission myocardial single-photon emission tomography using a technetium-99m-labelled radiotracer: impact on diagnostic accuracy  

Energy Technology Data Exchange (ETDEWEB)

The aim of this study was to quantify the potential benefit of attenuation correction by simultaneous emission and transmission imaging for the detection of CAD of vessels supplying the inferoposterior wall segments. In 25 male patients with {>=}50% stenoses of the right coronary artery and/or circumflex artery but without significant narrowing of the left anterior descending artery, stress studies using technetium-99m tetrofosmin (400 MBq) were carried out with and without attenuation correction. A dual-head camera with L-shaped detector positioning was equipped with two scanning gadolinium-153 line sources. Tomograms were reconstructed and quantified using circumferential count rate profiles of myocardial activity. The profiles were compared with the respective normal ranges obtained from 25 male patients. In patients without CAD, the maximal differences in count density of different wall segments were reduced from 29.0% in non-corrected (NC) studies to 9.5% in attenuation-corrected (AC) studies. In particular, the inferoposterior and septal wall segments were represented by significantly increased relative count densities after attenuation correction. The effects of attenuation correction proved independent of body mass. In patients with CAD, segmental count densities were abnormal in 84% of the NC studies and 100% of the AC studies. In single-vessel disease the stenotic vessel was identified in 66% of cases by NC studies and in 100% by AC studies. In AC studies, the extent and depth of defects exceeded those in NC studies. For the detection of CAD of the right coronary artery, the receiver operating characteristic (ROC) curves relating to the AC studies demonstrated improved discrimination capacity. ROC analysis of CAD detection yielded normalcy rates of 82% (NC) and 94% (AC) for the circumflex artery and 65% (NC) and 97% (AC) for the right coronary artery area at a sensitivity level of 95%. (orig./MG). With 3 figs., 5 tabs.

Kluge, R.; Sattler, B.; Seese, A.; Knapp, W.H. [Department of Nuclear Medicine, University of Leipzig (Germany)

1997-09-01

327

Single-photon quadratic optomechanics  

OpenAIRE

We present exact analytical solutions to study the coherent interaction between a single photon and the mechanical motion of a membrane in quadratic optomechanics. We consider single-photon emission and scattering when the photon is initially inside the cavity and in the fields outside the cavity, respectively. Using our solutions, we calculate the single-photon emission and scattering spectra, and find relations between the spectral features and the system's inherent parame...

Jie-Qiao Liao; Franco Nori

2014-01-01

328

Tomographic myocardial perfusion scintigraphy in children with Kawasaki disease  

International Nuclear Information System (INIS)

Myocardial infarction and stenotic coronary lesions are serious late complications in children with Kawasaki disease. For the noninvasive assessment of myocardial perfusion, dipyridamole-redistribution 201Tl emission computed tomography (ECT) was performed in seven children (age 2 8/12-8 7/12 yr) 3-20 mo after the acute stage of the disease. In all patients, coronary aneurysms had been demonstrated by cross-sectional echocardiography. The scintigrams of six children showed no significant regional reduction of myocardial thallium uptake. These children had remained asymptomatic since the acute stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with documented myocardial infarction. For this patient, obstruction of corresponding coronary vessels was confirmed by contrast angiography. It is suggested, that 201Tl ECT after dipyridamole-induced vasodilation may be used as a safe alternative to invasive coronary angiography for follow-up investigations in patients with Kawasaki disease

329

Single-photon emission computed tomography (SPECT): Applications and potential  

International Nuclear Information System (INIS)

Single-photon emission computed tomography has received increasing attention as radiopharmaceuticals that reflect perfusion, metabolism, and receptor and cellular function have become widely available. Perfusion single-photon emission computed tomography of the brain provides functional information useful for the diagnosis and management of stroke, dementia, and epilepsy. Single-photon emission computed tomography has been applied to myocardial, skeletal, hepatic, and tumor scintigraphy, resulting in increased diagnostic accuracy over planar imaging because background activity and overlapping tissues interfere far less with activity from the target structure when tomographic techniques are used. Single-photon emission computed tomography is substantially less expensive and far more accessible than positron emission tomography and will become an increasingly attractive alternative for transferring the positron emission tomography technology to routine clinical use

330

Precordial ST-segment depression during acute inferior myocardial infarction: clinical, scintigraphic and angiographic correlations  

International Nuclear Information System (INIS)

The cause and associated pathophysiology of precordial ST-segment depression during acute inferior myocardial infarction (IMI) are controversial. To investigate this problem, electrocardiographic findings in 48 consecutive patients with acute IMI were prospectively compared with results of coronary angiography, submaximal exercise thallium-201 (201Tl) scintigraphy and multigated blood pool imaging, all obtained 2 weeks after IMI, and with clinical follow-up at 3 months. Patients were classified according to the admission ECG obtained 3.3 +/- 3.1 hours after the onset of chest pain. Twenty-one patients (group A) had no or 201Tl perfusion abnormalities (p201Tl defects or wall motion abnormalities in anterior or septal segments

331

Attenuation-corrected thallium-201 single-photon emission tomography using a gadolinium-153 moving line source. Clinical value and the impact of attenuation correction on the extent and severity of perfusion abnormalities  

Energy Technology Data Exchange (ETDEWEB)

The aim of the study was to test the clinical value of attenuation-corrected (AC) thallium-201 single-photon emission tomography using a moving gadolinium-153 line source in a group of patients in whom coronary angiography was planned because of clinically suspected coronary artery disease (CAD). Furthermore, we wanted to test the impact of AC on assessment of the extent and severity of perfusion abnormalities. A total of 107 patients planned to undergo coronary angiography were included in the study. In each patient, AC and NC (non-corrected) {sup 201}Tl SPET was performed. AC and NC images were evaluated visually as well as by a 31-segment semiquantitative analysis and the findings were correlated with angiographic results. Patients were assigned to two groups: group A with angina and no previous cardiac infarction or intervention and group B with known CAD because of previous myocardial infarction or intervention. With visual analysis, NC revealed a sensitivity of 88.9% in group A and 74.3% in group B, compared to 94.4% in group A and 94.3% in group B with AC. Specificity for NC was calculated to be 68.7% for a group A and 91.3% for group B. AC demonstrated significantly higher specificity of 83.9% and 100%, respectively. This effect was particularly demonstrated for males and bicycle workload. The extent and severity of perfusion abnormalities were significantly influenced by the use of AC, in that significantly fewer abnormal and less severely abnormal segments were demonstrated in the segmental analysis as compared to NC; this was especially true for the vascular territory of the left anterior descending artery and the right coronary artery.(orig./MG)

Gallowitsch, H.J.; Mikosch, P.; Kresnik, E.; Unterweger, O.; Lind, P. [Landeskrankenhaus Klagenfurt (Austria). Dept. of Nuclear Medicine and Special Endocrinology; Sykora, J.; Grimm, G. [Landeskrankenhaus Klagenfurt (Austria). Dept. of Cardiology; Molnar, M.

1998-03-01

332

Attenuation-corrected thallium-201 single-photon emission tomography using a gadolinium-153 moving line source. Clinical value and the impact of attenuation correction on the extent and severity of perfusion abnormalities  

International Nuclear Information System (INIS)

The aim of the study was to test the clinical value of attenuation-corrected (AC) thallium-201 single-photon emission tomography using a moving gadolinium-153 line source in a group of patients in whom coronary angiography was planned because of clinically suspected coronary artery disease (CAD). Furthermore, we wanted to test the impact of AC on assessment of the extent and severity of perfusion abnormalities. A total of 107 patients planned to undergo coronary angiography were included in the study. In each patient, AC and NC (non-corrected) 201Tl SPET was performed. AC and NC images were evaluated visually as well as by a 31-segment semiquantitative analysis and the findings were correlated with angiographic results. Patients were assigned to two groups: group A with angina and no previous cardiac infarction or intervention and group B with known CAD because of previous myocardial infarction or intervention. With visual analysis, NC revealed a sensitivity of 88.9% in group A and 74.3% in group B, compared to 94.4% in group A and 94.3% in group B with AC. Specificity for NC was calculated to be 68.7% for a group A and 91.3% for group B. AC demonstrated significantly higher specificity of 83.9% and 100%, respectively. This effect was particularly demonstrated for males and bicycle workload. The extent and severity of perfusion abnormalities were significantly influenced by the use of AC, in that significantly fewer abnormal and less severely abnormal segme abnormal and less severely abnormal segments were demonstrated in the segmental analysis as compared to NC; this was especially true for the vascular territory of the left anterior descending artery and the right coronary artery.(orig./MG)

333

Application of pressure-derived myocardial fractional flow reserve in assessing the functional severity of coronary artery stenosis in patients with diabetes mellitus  

International Nuclear Information System (INIS)

Although the development of a coronary guidewire mounted with a pressure sensor has facilitated the measurement of pressure-derived fractional flow reserve (FFR) to assess the functional severity of coronary artery stenoses, the theoretical limitations include diabetes mellitus because of the associated microvascular abnormalities. In the present study 304 vessels and their coronary territories in 96 diabetic and 149 non-diabetic patients were evaluated by pressure-derived FFR and thallium-201 single photon emission computed tomography (SPECT) to determine the applicability of measuring FFR in diabetic subjects. The best cut-off value for FFR to detect myocardial ischemia, as demonstrated by 201Tl SPECT, was 0.725 in the diabetic and 0.745 in the nondiabetic patients. Sensitivity and specificity were similar for the 2 groups (83% and 75% (diabetic) vs 79% and 83%). However, diabetic patients with hemoglobin (Hb) A1c?7.0% showed lower specificity in comparison with those having HbA1c<7.0% (64 vs 88%; p=0.045); however, sensitivities were similar (83 vs 83%; p=NS). The cut-off value of 0.75 for FFR can detect myocardial ischemia in diabetic patients, although the adequacy of glycemic control should be taken into consideration when assessing the FFR measurements. (author)

334

Defect images in stress thallium-201 myocardial scintigraphy in patients with complete left bundle branch block. Comparison of exercise stress and pharmacological stress  

International Nuclear Information System (INIS)

Stress thallium-201 (201Tl) myocardial scintigraphy can demonstrate perfusion abnormalities, especially in the septum in patients with complete left bundle branch block (CLBBB) even with angiographically normal coronary arteries. Differences in the images between exercise and pharmacological stress 201Tl myocardial scintigraphy were evaluated in patients with CLBBB and normal coronary arteries. Forty-five patients with CLBBB underwent exercise stress using treadmill or pharmacological (adenosine triphosphate) stress 201Tl myocardial scintigraphy from October 1997 to February 2003. Patients with myocardial diseases were excluded, such as cardiomyopathy and coronary artery diseases detected by echocardiography and/or cardiac catheterization. The myocardial segment was classified according to the American Heart Association style for coronary artery disease. Peak blood pressure levels and heart rates were significantly higher in the exercise stress group than in the pharmacological stress group (p201Tl myocardial scintigraphy according to the stress method. Moreover, defects also occurred in areas other than the septum. Blood pressure and heart rate were involved in the mechanisms of defects in left bundle branch block. (author)

335

Single photon source characterization with a superconducting single photon detector  

CERN Document Server

Superconducting single photon detectors (SSPD) based on nanopatterned niobium nitride wires offer single photon counting at fast rates, low jitter, and low dark counts, from visible wavelengths well into the infrared. We demonstrate the first use of an SSPD, packaged in a commercial cryocooler, for single photon source characterization. The source is an optically pumped, microcavity-coupled InGaAs quantum dot, emitting single photons on demand at 902 nm. The SSPD replaces the second silicon Avalanche Photodiode (APD) in a Hanbury-Brown Twiss interferometer measurement of the source second-order correlation function, g (2) (tau). The detection efficiency of the superconducting detector system is >2 % (coupling losses included). The SSPD system electronics jitter is 170 ps, versus 550 ps for the APD unit, allowing the source spontaneous emission lifetime to be measured with improved resolution.

Hadfield, R H; Miller, A J; Mirin, R P; Nam, S W; Schwall, R E; Stevens, M J; Gruber, Steven S.; Hadfield, Robert H.; Miller, Aaron J.; Mirin, Richard P.; Nam, Sae Woo; Schwall, Robert E.; Stevens, Martin J.

2005-01-01

336

Single photon source characterization with a superconducting single photon detector.  

Science.gov (United States)

Superconducting single photon detectors (SSPD) based on nanopatterned niobium nitride wires offer single photon counting at fast rates, low jitter, and low dark counts, from visible wavelengths well into the infrared. We demonstrate the first use of an SSPD, packaged in a commercial cryocooler, for single photon source characterization. The source is an optically pumped, microcavity-coupled InGaAs quantum dot, emitting single photons at 902 nm. The SSPD replaces the second silicon Avalanche Photodiode (APD) in a Hanbury-Brown Twiss interferometer measurement of the source second-order correlation function, g(2)( ?). The detection efficiency of the superconducting detector system is >2 % (coupling losses included). The SSPD system electronics jitter is 170 ps, versus 550 ps for the APD unit, allowing the source spontaneous emission lifetime to be measured with improved resolution. PMID:19503303

Hadfield, Robert H; Stevens, Martin J; Gruber, Steven S; Miller, Aaron J; Schwall, Robert E; Mirin, Richard P; Nam, Sae Woo

2005-12-26

337

Evaluation of myocardial viability with cardiac PET before and after CABG and the study of hibernating myocardium  

Energy Technology Data Exchange (ETDEWEB)

This study included 28 patients in whom graft patency after coronary artery bypass graft (CABG) was confirmed by coronary angiography. Diagnosis included angina pectoris following myocardial infarction and severe angina pectoris accompanied by stenosis at the left main trunk region or lesion involving multiple branches. As a rule, cardiac PET ({sup 13}NH{sub 3}, {sup 18}FDG) was performed in fasted patients before and 1 to 2 months after surgery. Myocardial blood flow and glucose metabolism in the bypass site were mainly investigated. Furthermore, {sup 201}Tl-SPECT was concurrently performed. The effect of CABG was examined by the two procedures, and redistribution was compared between PET and {sup 201}Tl-SPECT. Preoperative PET with {sup 13}NH{sub 3} revealed reduced blood flow in the ischemic site in all patients. However, preoperative {sup 201}Tl-SPECT showed redistribution in 16 (57.1%) of 28 patients, while there was no redistribution in 12 patients (42.9%). In 10 (83.3%) of 12 patients evaluated as having no myocardial viability on {sup 201}Tl-SPECT, PET showed accumulation of {sup 18}FDG. However, in 21 (75%) of 28 patients, accumulation of {sup 18}FDG was reduced postoperatively, suggesting improvement of aerobic metabolism in cardiac muscle. These patients also showed improvement in regional wall motion. The energy source of cardiac muscle consists mainly of free fatty acid and glucose. Fasting healthy cardiac muscle depends on fatty acid for approximately 60% of its energy source. However, ischemic cardiac muscle depends on the glycolytic system, utilizing glucose. Progression of ischemia causes myocardial necrosis without metabolism. Therefore, ischemic cardiac muscle can be differentiated from infarcted cardiac muscle by cardiac PET. We evaluated myocardial viability before and after CABG for ischemic heart disease, and confirmed that cardiac PET is more useful than standard myocardial scan with {sup 201}Tl for evaluating myocardial viability. (K.H.)

Adachi, Masahiro; Sakamoto, Shigeru [Kanazawa Medical Univ., Uchinada, Ishikawa (Japan); Seki, Hiroyasu

1997-09-01

338

Measurement of regional myocardial blood flow by intracoronary arterial injection of 133Xe  

International Nuclear Information System (INIS)

201Tl myocardial perfusion imaging (MPI) has been established as a noninvasive method to evaluate myocardial blood flow distribution, which is a function of myocardial mass and blood flow. To measure the blood flow specifically, a washout process of 133Xe was analyzed to calculate the specific flow in each regional element, that is regional myocardial blood flow (RMBF). The RMBF was expressed in a form of spacial distribution, so-called functional image, and was compared with the 201Tl MPI. 30 cases including 5 with normal or mild coronary artery disease (CAD) (Group I), 10 with severe CAD (Group II) and 15 with hypertrophic or congestive cardiomyopathy (Group III) were studied. Following coronary angiography, 133Xe in saline solution was injected into the coronary artery and the washout process was imaged to be analyzed during initial 40 seconds in LAO 300 by a multicrystal gamma camera. RMBF in each regional element was calculated according to the initial slope method to be analyzed as the functional image' 201Tl MPI was also performed in RAO 300, anterior, LAO 300, LAO 450, LAO 600 and left lateral position. Regional distribution of these two methods concerning myocardial perfusion were compared each other. These observed to be reasonable correlation between RMBF and MPI of Group I and Group II. However, in several cases of Group III, abnormal perfusion of cases of Group III, abnormal perfusion of hypertrophied mass was suggested to be present in the RMBF image, which could not be resolved in 201Tl MPI but only hypertrophied mass was visualized. In conclusion, present type of imaging provided supplemental information to the conventional 201Tl MPI. (author)

339

Examination of the findings on [sup 201]Tl, [sup 123]I-BMIPP dual cardiac SPECT in acute phase of Kawasaki disease  

Energy Technology Data Exchange (ETDEWEB)

In 42 cases with acute phase of Kawasaki disease (3-27 days since pathopoiesis), [sup 201]Tl, [sup 123]I-BMIPP dual cardiac SPECT was performed and the reduction of the isotope-uptake was macroscopically assessed. On cardiac SPECT, 28 of 42 cases (67%), and 19 of 30 cases (63%) who were normal on electrocardiogram, echocardiogram and blood CK levels showed abnormal images. In a part of cases showing abnormal cardiac SPECT, coronary arteriography was performed, and constrictive lesions with more than 25% were not observed. In acute phase of Kawasaki disease, the risk of cardiac complication was thought to be low. But these results suggest that there are cardiac complications detectable by [sup 201]Tl, [sup 123]I-BMIPP dual cardiac SPECT. This cardiac lesions were thought to be intramyocardinal microangiitis or abnormal coronary micro circulation cased by myocarditis associating microangiitis. (K.H.)

Koga, Yutaka (Matsushita-Kotobuki Electronics Industries Ltd., Ohzu, Ehime (Japan)); Ishizuka, Takehiro; Otabe, Hiroyuki; Kori, Takeo; Ota, Toshiko; Suzuki, Kazushige

1999-02-01

340

Examination of the findings on {sup 201}Tl, {sup 123}I-BMIPP dual cardiac SPECT in acute phase of Kawasaki disease  

Energy Technology Data Exchange (ETDEWEB)

In 42 cases with acute phase of Kawasaki disease (3-27 days since pathopoiesis), {sup 201}Tl, {sup 123}I-BMIPP dual cardiac SPECT was performed and the reduction of the isotope-uptake was macroscopically assessed. On cardiac SPECT, 28 of 42 cases (67%), and 19 of 30 cases (63%) who were normal on electrocardiogram, echocardiogram and blood CK levels showed abnormal images. In a part of cases showing abnormal cardiac SPECT, coronary arteriography was performed, and constrictive lesions with more than 25% were not observed. In acute phase of Kawasaki disease, the risk of cardiac complication was thought to be low. But these results suggest that there are cardiac complications detectable by {sup 201}Tl, {sup 123}I-BMIPP dual cardiac SPECT. This cardiac lesions were thought to be intramyocardinal microangiitis or abnormal coronary micro circulation cased by myocarditis associating microangiitis. (K.H.)

Koga, Yutaka [Matsushita-Kotobuki Electronics Industries Ltd., Ohzu, Ehime (Japan); Ishizuka, Takehiro; Otabe, Hiroyuki; Kori, Takeo; Ota, Toshiko; Suzuki, Kazushige

1999-02-01

341

A study of states in 201Tl, 203Tl using the (d,3n?) reaction: a new 9/2- band  

International Nuclear Information System (INIS)

The nuclei 201Tl, 203Tl were formed in (d,3n) reactions. Studies of the de-excitation ?-rays are described and level schemes are deduced for both isotopes. Evidence is presented for the existence in 201Tl of a rotational band built on the 9/2- isomeric state at 920 keV. The band is compared to the 9/2- bands occurring in the odd isotopes 191Tl-199Tl and is shown to be well described by a symmetric rotor-plus-particle model. The model predictions for the low-lying positive parity states are also considered and satisfactory agreement with experimental data is obtained. No 9/2- band was observed in 203Tl and possible interpretations of this result are presented. (author)

342

Single-photon quadratic optomechanics  

Science.gov (United States)

We present exact analytical solutions to study the coherent interaction between a single photon and the mechanical motion of a membrane in quadratic optomechanics. We consider single-photon emission and scattering when the photon is initially inside the cavity and in the fields outside the cavity, respectively. Using our solutions, we calculate the single-photon emission and scattering spectra, and find relations between the spectral features and the system's inherent parameters, such as: the optomechanical coupling strength, the mechanical frequency, and the cavity-field decay rate. In particular, we clarify the conditions for the phonon sidebands to be visible. We also study the photon-phonon entanglement for the long-time emission and scattering states. The linear entropy is employed to characterize this entanglement by treating it as a bipartite one between a single mode of phonons and a single photon.

Liao, Jie-Qiao; Nori, Franco

2014-09-01

343

Use of 99mTc-MIBI scintigraphy in the evaluation of the response to chemotherapy for osteosarcoma. Comparison with 201Tl scintigraphy and angiography  

International Nuclear Information System (INIS)

In the treatment of osteosarcoma, the chemotherapeutic effect influences decisions regarding the surgical margin, continuation of chemotherapy, and choice of anticancer drugs for further chemotherapy. Therefore, it is necessary to evaluate the response to chemotherapy in the middle of the chemotherapy course. In this study, we investigated the use of 99mTc-hexakis-2-methoxyisobutyl-isonitrile (99mTc-MIBI) scintigraphy in evaluating the response to chemotherapy of patients with osteosarcoma in comparison with 201Tl scintigraphy and angiography. A total 45 patients with osteosarcoma were examined using 99mTc-MIBI scintigraphy, 201Tl scintigraphy, and angiography to evaluate their response to chemotherapy. The percentage reduction in the uptake ratios (?UR) calculated as 100 x [(prechemotherapy value - postchemotherapy value)/prechemotherapy value] were compared with histological assessments. Similarly, changes in tumor vascularity assessed by angiograms were compared with histological assessments. On the angiographic findings, the results were classified as complete response (CR), partial response (PR), no change (NC), or progressive disease (PD). On the images, ?UR in 99mTc-MIBI ?30% and ?UR in 201Tl ?30% were classified as responder, as were CR and PR in angiograms. The therapeutic effect was assessed by histopathological examination of the resected specimens. The tumors of poor responpecimens. The tumors of poor responders showed less than 90% necrosis, whereas the tumors of good responders showed 90% or more necrosis. Sensitivity, specificity, and accuracy were 73.9, 84.2, and 78.6%, respectively, for 99mTc-MIBI (?=0.57); 80.0, 61.1, and 72.1%, respectively, for 201Tl (?=0.42); and 91.7, 35.0, and 65.9%, respectively for angiography (?=0.28). 99mTc-MIBI could be effectively used to predict the final response to chemotherapy of osteosarcoma. (author)

344

An approach based on the SIR measurement model for determining the ionization chamber efficiency curves, and a study of 65Zn and 201Tl photon emission intensities.  

Science.gov (United States)

The measurement model used to determine ionization chamber efficiency curves accounts from the outset for impurity corrections and beta spectrum shapes. The curves are represented by exponentials of polynomials whose coefficients are adjusted using non-linear least-squares minimization. The curves are validated by comparing with SIR key comparison reference values (KCRVs) and other published curves. The associated covariance matrix is also evaluated. Deviations from model predictions for 65Zn and 201Tl using recommended nuclear data are studied. PMID:16574424

Michotte, C; Pearce, A K; Cox, M G; Gostely, J-J

2006-01-01

345

Evaluation of primary lung cancer and mediastinal lymph node metastasis using 99mTc-MIBI. Comparison with 201Tl and relation to chemotherapeutic effect  

International Nuclear Information System (INIS)

We compared the detectability of 99mTc-MIBI and 201Tl-chloride for primary lung cancer and mediastinal lymph node metastasis. We also analyzed the relationship between 99mTc-MIBI uptake and effectiveness of chemotherapy in patients with small cell lung cancer. The subjects were forty-six primary lesions and 8 mediastinal metastatic lymph nodes confirmed by operation, and dual-isotope SPECT technique was performed at both 20 min and 180 min after tracer injection. A tumor to normal lung ratio on both early (ER) and delayed image (DR) and retention index (RI) were calculated. The positive rates of 99mTc-MIBI(early; 82.6%, delayed; 54.3%) were comparable to 201Tl in most primary tumor (87.0% and 84.8%). Whereas tumor smaller than 3 cm diameter was poorly visualized on both 99mTc-MIBI (25% and 0%) and 201Tl and (37.5% and 37.5%). Detectabilities of metastatic mediastinal lymph nodes of 99mTc-MIBI (62.5% and 25.0%) was comparable to those of 201Tl (62.5% and 50.0%). Regarding effectiveness of chemotherapy, NC group showed lower uptake of 99mTc-MIBI and significant lower value of RI compared to PR group. We concluded that early image of 99mTc-MIBI SPECT can be helpful in detecting primary lung cancer and metastatic mediastinal lymph node. Additionally, it might be useful for predicting the effects of chemotherapy in small cell lung cancer. (author)in small cell lung cancer. (author)

346

Usefulness of 201Tl SPECT in the predication of mediastinal lymph nodes metastasis in patients with non small cell lung carcinoma (NSCLC)  

International Nuclear Information System (INIS)

Predictivity of mediastinal lymph nodes metastasis of 201Tl SPECT were examined before operation in 113 patients with non-small cell lung cancer (69 adenocarcinoma, 31 squamous cell carcinoma, 10 large cell carcinoma, 2 bronchiolo-alveolar carcinoma, 1 neuroendocrine cell carcinoma). Patients were classified into two groups, with or without lymph nodes metastasis according to the pathological diagnosis. We calculated parameters of 201Tl SPECT early ratio, delayed ratio, retention index (RI) and maximal diameters. In addition, we calculated optimal cut-off value of RI to estimate the mediastinal lymph nodes metastasis. Mediastinal lymph nodes metastasis was confirmed pathologically in 62 patients. Early ratio (ER) and delayed ratio (DR) did not show any statistical significance between two groups. Maximal diameters of primary tumor were also comparable between two groups. RI was significantly higher in mediastinal lymph node metastasis positive group compared to that in mediastinal lymph node metastasis negative group. The sensitivity (Sen), specificity (Spe), positive predictive value (PPV), negative predictive value (NPV) and accuracy (Acc) of 201Tl SPECT were 82.2%, 82.3%, 85.0%, 79.2% and 82.3%. These parameters were similar of higher than 72.6%, 82.4%, 83.3%, 71.2% and 77.0% of chest CT. The RI of 201Tl SPECT was useful tool for predicting lymph nodes metastasis in non-small cell lung cancer. The optimum cut-off value of lung cancer. The optimum cut-off value of RI in the prediction of mediastinal lymph nodes metastasis was 35%. We should take into account of upstaging in cases with higher RI (>35%). (author)

347

ROC analysis of tumor detectability using 201Tl (I) chloride and 99mTc (I) hexakis (2-methoxy-2-isobutylisonitrile)  

International Nuclear Information System (INIS)

We investigated tumor detectability of bronchial carcinoma using 201Tl and 99mTc-MIBI with planar scintigraphy and SPECT. We studied 30 tumor patients and 7 patients with coronary artery disease in a clinical phase III trial. The lung was partitioned into 6 areas, which were read independently, to provide a sufficiently large sample of tumor-free reference regions. We calculated the statistical power for the comparison of sensitivities at a given specificity of 95% (TPF-test) to demonstrate that the subdivision of the lung and the application of the bivariate binormal ROC model allows an objective assessment of diagnostic performance even for the small sample size of our study. There were no significant differences between 201Tl and 99mTc-MIBI for both observers; therefore, no advantage of 99mTc-MIBI over 201Tl for tumor scintigraphy could be demonstrated. SPECT was significantly superior to planar scintigraphy and sould be preferred for tumor detection in the thorax. (orig.)

348

Comparison of myocardial scintigraphy, myocardial lactate extraction and coronary sinus blood flow before after coronary artery bypass surgery  

International Nuclear Information System (INIS)

Studies were performed to validate exercise and delayed rest (5 hours) TL-201 myocardial perfusion scanning for the detection of myocardial ischemia before and after coronary artery bypass surgery. In 15 patients (13 male, 2 female), mean age 53 +- 8 years 201-TL-scintigraphy were performed in four different positions before (mean: 3 months) and after (mean: 5 months) coronary artery bypass surgery. 201-TL-scintigrams were processed by computer-assisted quantitation. Transmyocardial lactate extraction was calculated from lactate concentration in the arterial and coronary sinus blood. Lactate extraction and coronary sinus blood flow were measured at rest and during supraventricular pacing. 33 bypass grafts were implanted with 27 postoperatively patent. In clearly reversible defect regions, 201-TL uptake and washout were significantly reduced (0.58 +- 0.03 SD and 0.62 +- 0.45, resp. compared to normal < 0.85 resp. < 0.90). In constant defect regions, only 201-TL uptake was diminished (0.61 +- 0.30) in the presence of a normal washout (1.03 +- 0.45). After coronary artery bypass surgery, 201-TL uptake increased significantly to 0.65 +- 0.60 (p < 0.001) in reversible defect regions, but remained unchanged in constant defect regions. Diminished washout became normal in most reversible defect regions with no change in constant defect regions. Preoperatively lactate extraction at rest was 20 +- 27% and decreased during pacing to -2 +- 26% (p < 0.01). After coronary artery by- 26% (p < 0.01). After coronary artery bypass surgery, lactate extraction at rest was 38 +- 15%, during pacing it decreased to 12 +- 48% (n.s.). Preoperatively coronary sinus blood flow increased from 128 +- 22 ml/min to 208 +- 63 ml/min. (orig./APR)

349

Comparison of myocardial imaging with iodine-123-iodophenyl-9-methyl pentadecanoic acid and thallium-201-chloride for assessment of patients with exercise-induced myocardial ischemia  

Energy Technology Data Exchange (ETDEWEB)

Iodine-123-iodophenyl-9-methyl-pentadecanoic acid (({sup 123}I)MPDA) and thallium-201 ({sup 201}Tl) were sequentially injected in 11 patients during exercise-induced myocardial ischemia. Simultaneous dual-energy planar images were obtained at 5 min, 3 and 5 hr. All studies were concordantly either positive (8/11) or negative (3/11) by both radionuclides. Exact agreement for segmental uptake was 93%, 94% and 94% for 5-min, 3- and 5-hr images, respectively. Exact agreement for defect reversibility by 3 and 5 hr were 95% and 92%. The initial defect contrasts and myocardial-to-lung ratios were similar by both agents but myocardial-to-liver ratio was lower by ({sup 123}I)MPDA at 5 min, which became similar to {sup 201}Tl at 5 hr. Normal percent myocardial clearances of both agents were comparable and significantly higher than those in defect zones. Thus ({sup 123}I)MPDA is suitable for myocardial imaging and correlates closely with {sup 201}Tl for initial postexercise myocardial uptake and defect reversibility. Defect reversibility appears to result from differential myocardial clearance from normal and ischemic regions.

Chouraqui, P.; Maddahi, J.; Henkin, R.; Karesh, S.M.; Galie, E.; Berman, D.S. (Cedars-Sinai Medical Center, Los Angeles, CA (USA))

1991-03-01

350

Comparison of myocardial imaging with iodine-123-iodophenyl-9-methyl pentadecanoic acid and thallium-201-chloride for assessment of patients with exercise-induced myocardial ischemia  

International Nuclear Information System (INIS)

Iodine-123-iodophenyl-9-methyl-pentadecanoic acid [(123I]MPDA) and thallium-201 (201Tl) were sequentially injected in 11 patients during exercise-induced myocardial ischemia. Simultaneous dual-energy planar images were obtained at 5 min, 3 and 5 hr. All studies were concordantly either positive (8/11) or negative (3/11) by both radionuclides. Exact agreement for segmental uptake was 93%, 94% and 94% for 5-min, 3- and 5-hr images, respectively. Exact agreement for defect reversibility by 3 and 5 hr were 95% and 92%. The initial defect contrasts and myocardial-to-lung ratios were similar by both agents but myocardial-to-liver ratio was lower by [123I]MPDA at 5 min, which became similar to 201Tl at 5 hr. Normal percent myocardial clearances of both agents were comparable and significantly higher than those in defect zones. Thus [123I]MPDA is suitable for myocardial imaging and correlates closely with 201Tl for initial postexercise myocardial uptake and defect reversibility. Defect reversibility appears to result from differential myocardial clearance from normal and ischemic regions

351

Tcsup(99m)-DMPE, a potential substitute for 201Tl chloride  

International Nuclear Information System (INIS)

The systematic search for Tcsup(99m) labelled myocardium imaging agents resulted in a series of monocationic Tcsup(99m) complexes of known chemical structure. Of these agents Tcsup(99m)-DMPE appears to be the most promising one, because it is water soluble. The use of this agent in man however, is limited by two effects: a) DMPE is a toxic agent and care has to be taken that the toxic levels are not exceeded. b) The biodistribution of Tcsup(99m)-DMPE is less favorable in man than in the rat and dog, due to differences in plasma protein binding. The authors concluded that a Tcsup(99m) labelled myocardial imaging agent has to be especially designed for use in man. (Auth.)

352

Thallium-201 uptake ratio correlated with myocardial mass ratio in chronically hypertrophied rat hearts induced by preferential pressure or volume overload  

Energy Technology Data Exchange (ETDEWEB)

Hemodynamic measurements, left to right myocardial ventricular mass ratio and myocardial thallium-201 ({sup 201}Tl) uptake ratio were measured in 6 normal and the following 30 experimental rats (each group, n=6). Right ventricular (RV) pressure overload (PO) was induced by administration of monocrotaline. RV volume overload (VO) was induced by suturing a pulmonary valve to the pulmonary artery. Biventricular (BV) VO was induced by creation of an aortocaval fistula. Left ventricular (LV) PO was induced by constriction of the ascending aorta and LVVO was induced by destruction of the aortic valves. RV mass to body weight (BW) was significantly increased in RPVO, RVVO and BVVO models compared with the control. LV mass to BW was significantly increased in LVPO, LVVO models. RV peak systolic pressure (PSP) was significantly increased in RVPO, BVVO and LVVO models, and LVPSP was significantly increased in LVPO, BVVO and LVVO models. LV/RV mass ratio was significantly decreased in RVPO, RVVO and BVVO models, and was significantly increased in LVPO and LVVO models. LV/RV myocardial {sup 201}Tl uptake ratio was significantly decreased in RVPO and RVVO models, and was significantly increased in LVPO and LVVO models. Linear regression analysis showed an excellent correlation between LV/RV myocardial {sup 201}Tl uptake ratio and LV/RV mass ratio. Although the presence of significant correlation between LV/RV pressure ratio and LV/RV myocardial {sup 201}Tl uptake ratio was confirmed in PO models, rather poor correlation was observed in VO models. Our results suggest that LV/RV myocardial mass ratio as well as LV/RV pressure ratio can be evaluated by LV/RV myocardial {sup 201}Tl uptake ratio in chronic overload models. (S.Y.).

Taniguchi, Masashi [Kanazawa Univ. (Japan). School of Medicine

1995-10-01