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1

Quantitative evaluation of 201TlCl myocardial tomography using SPECT (single photon emission computed tomography)  

International Nuclear Information System (INIS)

201Tl myocardial tomography using SPECT (Single Photon Emission Computed Tomography) was evaluated experimentally. With regard to data acquisition, every five or ten degrees, 30 seconds per one direction were needed. Comparing the single head 1800 with dual-head 3600 data acquisition, there was a little difference in the imagings but there was no difference to detect the perfusion defect clinically. With regard to data analysis, myocardial long-axial and short-axial imagings were constracted. These imagings were not homogenious instead of proper absorption correction. The estimation of autopsy revealed the cause of that inhomogenicity, that the thickness of myocardial wall was not homogeneous and symmetric and the length of septal wall was shorter than that of lateral wall. So, the diagnosis of myocardial perfusion in the myocardial ECT imagings depends on the evaluation of the degree of the density. This is very delicate work for visual diagnosis, and on the other hand the quantitative analysis seems to be suitable. The tomographic precision of SPECT method was evaluated. As the result, the precision of SPECT was proved to be very excellent, as far as the adjustment of dualhead cameras was correct. (author)

2

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

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

3

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

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

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

2001-09-01

4

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  

International Nuclear Information System (INIS)

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)

5

Relationship between the mismatch of 123I-BMIPP and 201Tl myocardial single-photon emission computed tomography and autonomic nervous system activity in patients with acute myocardial infarction  

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The purpose of this study was to elucidate the relationship between the mismatch of thallium-201 (Tl) and iodine-123-beta-methyl-iodophenyl-pentadecanoic acid (BMIPP) myocardial single-photon emission computed tomography (SPECT) and autonomic nervous system activity in myocardial infarction (MI) patients. The subjects were 40 patients (34 males, 6 females) who underwent examinations by 123I-BMIPP and 201Tl myocardial SPECT imaging and 24-hour Holter monitoring within a 3-day period 3 weeks after the onset of their first MI. R-R intervals were analyzed every hour over a period of 24 hours by fast Fourier transformation (FFT). High frequency (HF) and low frequency (LF) were defined as markers of cardiac vagal activity in the former and the LF/HF ratio as sympathetic activity. Greater or more extensive decreases in the BMIPP image than that in the Tl image were defined as a positive mismatch. Patients were divided into positive and negative mismatch groups of 20 patients each. There were no significant differences between the 2 groups in age, sex, site of infarction, max CK (creatine kinase), max CK-MB, or left ventricular ejection fraction. The incidences of clinical signs suggesting residual myocardial ischemia were significantly greater in the positive than in the negative mismatch group (P123I-BMIPP and 201Tl myocardial SPECT 3 weeks after a first acute myocardial infarction with uncomplicated moderate or severe heart failure and decreased heart rate variability are related to residual myocardial ischemia. A combined assessment of heart rate variability in 24 hour Holter electrocardiogram (ECG) monitoring and perfusion-metabolism mismatch in 123I-BMIPP and 201Tl myocardial SPECT is useful for determining residual myocardial ischemia in the follow-up of those with acute myocardial infarction. (author)

6

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

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

7

New application of myocardial infarct map using a dual isotope single photon emission computed tomography (SPECT) of [99mTc]pyrophosphate and [201Tl]chloride in patients with acute myocardial infarction  

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In 12 patients with acute myocardial infarction, a dual isotope SPECT was applied to describe a myocardial infarct map for detecting the site and the extent of the infarct. Threshold cut-off level was determined as 55 % for [99mTc] and 35 % for [201Tl] according to cardiac phantom studies. Multiple cardiac tomograms showed two different uptakes of the isotopes in indentical slices and regions. Then, color tomograms were described on the red and green image for [99mTc] and for [201Tl], respectively, and Bulls eye map was drawn in the two colored fashion as the myocardial infarct map. In all patients, the infarct map was successful to determine the exact site of the infarct and the overlapped area by the viable myocardium. In conclusion, this functional map of acute myocardial infarction may be useful for understanding three dimensional area of the infarct and the viable myocardium easily and exactly. (author)

8

Methods, qualitative and quantitative evaluations of 201Tl myocardial scintiscans  

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Exercise 201Tl myocardial scintiscanning is a technique used to supplement exercise electrocardiography. The procedure employed should be identical to the standard procedure of electrocardiography. If the coronary disease has already been established by coronary angiography and kineventriculography, 201Tl examinations should be carried out before surgery in order to determine the ''regional functional reserve''. Visual evaluations of the 201Tl scintiscans should be supplemented by quantification methods. Quantification is also required between 201Tl examination and surgery and to assure constant diagnostic accuracy in case of examination by different examiners. (orig./MG)

9

A new polar map to quantify reversible area by myocardial 201Tl single photon emission computed tomography and clinical application to patients before and after percutaneous transluminal coronary angioplasty  

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In the studies of stress 201Tl single photon emission computed tomography, we have developed a computer method to discriminate reversible from irreversible defect, then quantify each area and display the area on the polar map. Initial percent uptake (%Ui) and delayed percent uptake (%Ud) were expressed as percent of the maximum uptake area and were defined as regional myocardial 201Tl uptake in initial and delayed image, respectively. The %Ud/%Ui ratio was defined as redistribution ratio (RD-ratio). The values of %Ui obtained from each pixel of short axis slices were plotted against the values of RD-ratio on XY co-ordinates. In this graphic display, normal area, ischemic viable area and non viable area were separated by the following four lines: (A) the straight line (Y=2.0-0.012X) indicating the relationship between %Ui and RD-ratio for the group with ischemic viable myocardium; (B) the parallel line to A and shifted to -1.5 SD from A; (C) the vertical line at 67.0% level (ischemic upper level); (D) the vertical line at 27.6% level (viable lower level). Each area was discriminated by color display and calculated relative area values were displayed on the polar map. Criteria for discriminating each area were derived from the results of ischemic pre-trans-luminal coronary angioplasty (PTCA) lesions (n=21) in which viability was confirmed by successful PTCA and previous results of 66 cases of single vessel disease and 16 cases of control group. Thidisease and 16 cases of control group. This new computerized technique was applied for evaluation of another group with successful PTCA (n=15). Ischemic viable area decreased from 37.3 to 1.3 percent in patients without prior myocardial infarction and it decreased from 40.1 to 18.6 percent in patients with prior myocardial infarction. Non viable area in patients with prior myocardial infarction decreased from 9.7 to 2.9 percent. In conclusion, this technique may be useful for quantitative assessment of myocardial viability before and after PTCA. (author)

10

Quantitative analysis of 201Tl-myocardial imaging  

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Effects of vasodilators, NTG, Dipyridamole, and Nifedipine, were evaluated by 201Tl-myocardial scintigraphy. Dipyridamole and Nifedipine significantly increased the heart rate, and NTG and Nifedipine slightly decreased the blood pressure. A significantly decreased back ground ratio of the lung field was noted after administration of Nifedipine. In normal myocardial area, measured uptake counts which were significantly higher than predicted uptake counts were obtained after administration of NTG, Dipyridamole, Nifedipine. In ischemic myocardial area, with administration of NTG and Nifedipine, measured 201Tl-uptake counts became significantly higher than predicted uptake counts. The difference between normal and ischemic myocardial areas increased by the administration of Dipyridamole. These results suggested that these three kinds of vasodilators increase 201Tl-uptake. (Ueda, J.)

11

Myocardial scintigraphy (SPECT) with 201-Tl and 99mTc-HMIBI - execution and evaluation  

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Compared to planar acquisition technique, the use of SPECT (Single Photon Emission Computer Tomography) in myocardial scintigraphy (MS) is advantageous, yet imposing the necessity of a profound knowledge of the typical sources of errors at the present state of technology (rotating Gamma-cameras). From a more practical point of view, hints are given herein how to carry out and evaluate the examinations, employing both the customary perfusion tracers (201-Tl and 99mTc-HMIBI). (orig.)

12

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

13

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)

14

Spontaneous changes in 201Tl myocardial perfusion imaging after myocardial infarction  

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

15

When is 201Tl myocardial scintigraphy indicated?  

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

16

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

17

The quantitative analysis of 201Tl myocardial emission computed tomography in patients with old myocardial infarction  

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Circumferential profiles for 201Tl two-dimensional myocardial planar images and 201Tl myocardial emission computed tomography (ECT) images at rest were generated from 52 patients with old myocardial infarction undergoing left ventriculography (LVG). Normal profile curves were obtained from the ECT images in normal volunteers. Infarct areas were estimated based on the profile curves: Findings obtained coincided well with abnormal wall motion in LVG. Qualitative analysis of ECT images was superior to that of two-dimensional planar images in the diagnostic sensitivity and specificity. There was a significant positive correlation between the ratio of infarct size to the total left ventricular volume, which was obtained from shortaxial ECT images, and percent abnormally contracting segment with r = 0.74 (p 201Tl myocardial ECT images is an objective, reliable, and non-invasive method in the diagnosis of location and size of old myocardial infarction. (Namekawa, K.)

18

Myocardial scintigraphy (SPECT) with 201-Tl and 99mTc-HMIBI - execution and evaluation. Myokardszintigraphie (SPECT) mit 201-Tl und 99mTc-HMIBI - Durchfuehrung und Auswertung  

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Compared to planar acquisition technique, the use of SPECT (Single Photon Emission Computer Tomography) in myocardial scintigraphy (MS) is advantageous, yet imposing the necessity of a profound knowledge of the typical sources of errors at the present state of technology (rotating Gamma-cameras). From a more practical point of view, hints are given herein how to carry out and evaluate the examinations, employing both the customary perfusion tracers (201-Tl and 99mTc-HMIBI). (orig.).

Stirner, H.; Picker, D.; Brauner, B. (Klinikum Ingoldstadt (Germany). Inst. fuer Nuklearmedizin)

1991-06-01

19

201Tl myocardial tomography with polar bullseye plot display  

International Nuclear Information System (INIS)

In this study, 13 normal subjects and 43 CHD patients underwent 201Tl myocardial SPECT were presented and analysed with Polar Bullseye Plot (PBP). The sensitivity of tomography and PBP for detecting CHD was 93.0% and 97.6% respectively (P > 0.05). The specificity of both techniques was the same (92.3%). The sensitivity of tomography and PBP for detecting CHD patients with 1, 2 and 3 vessel lesion was 86.7% and 86.7%, 92.3% and 100%, 100% and 100%, respectively. The general sensitivity for detecting stenosed vessels was 84.7%. The sensitivity for examing severe stenosed vessel was higher than that for mild one (P LAD < LCX. As compared with general inspection of the image, obviously the advantage of PBP was objective, semi-quantitative and easy for glance over

20

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.)

 
 
 
 
21

H/S ratio as a new index for myocardial 201Tl uptake  

International Nuclear Information System (INIS)

In order to evaluate myocardial blood flow with 201Tl, a new myocardial 201Tl uptake index ''H/S ratio'' is proposed. H/S ratio is derived from left ventricular first pass time activity curve by 1/2 weighted background subtraction and exponential curve fitting in order to exclude lung uptake of 201Tl. With this H/S ratio, myocardial uptake of 201Tl based upon total dose passing through left ventricle can be estimated. H/S ratio is calculated in 12 patients with old myocardial infarction (OMI), 8 with heart diseases without ischemia (HD) and 3 noncardiac patients (NHD). H/S is 5.95 +- 1.75 (S.D.) for NHD, 4.79 +- 1.84 (S.D.) for HD and 3.47 +- 1.18 (S.D.) for OMI group. Difference is significant between OMI and the others (p 201Tl divided by the product of total dose passing through the left ventricle and mean transit time of the left ventricle [H/(q0.average t)]. Results of this study support this theoretical consideration. H/S is simple and useful myocardial 201Tl uptake index rather than H/T, because of excluding useless lung uptake of 201Tl. (author)

22

Combined scatter and attenuation correction for 201Tl myocardial perfusion SPECT using OS-EM algorithm  

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n image quality was observed between the two methods. In conclusion, both the SC(T) and SC(E) methods provided significant and similar improvement in the removal of scatter in 201Tl myocardial perfusion SPECT imaging. (author)

23

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)

24

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.)

25

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 ventricular function after myocardial infarction. (author)

26

Comparative study of 201Tl-scintigraphic image and myocardial pathologic findings in patients with dilated cardiomyopathy  

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The objective of the present study was to characterize the production of 201Tl myocardial perfusion defects, the relation between the 201Tl multiple small defects and the myocardial damage indicated by myocardial fibrosis shown histopathologically in patients with dilated cardiomyopathy (DCM). Rest 201Tl scintigraphy was performed in thirty-seven patients. 201Tl myocardial SPECT images were visually classified into 4 grades according to the severity of inhomogeneous perfusion defects (IPD), 0: none, 1: slight, 2: moderate, 3: severe. 201Tl uptake, defect regions (DR), and coefficient of variation % (CV%) were also quantified by Bull's eye quantification in nineteen patients. 201Tl perfusion defects were observed in 35 (94.6%) patients, of whom 29 (78.4%) showed inhomogeneous perfusion defects. Twenty-four (64.9%) showed Stage 0 and 1 201Tl findings, and 21 (62.2%) had myocardial fibrosis in stage 1. Clinically, the correlation between the grades of the IPD, % 201Tl uptake, DR and CV% of myocardial uptake, which were calculated semiquantitatively by Bull's eye image, and the histological grades of fibrosis were also good (IPD vs. fibrosis: r=0.7014; % 201Tl uptake vs. fibrosis: r=-0.6542; DR vs. fibrosis: r=0.7027; CV% vs. fibrosis: r=0.6985). The 201Tl SPECT findings were in close agreement with the severity of myocardial fibrosis confirmed by autopsy, but the grading of the IPD was not related to the ejection fraction or left ventricular diameter. It showed a higher rate of inhomogeneous 201Tl myocardial perfusion defects (78.4%) in patients with DCM. This result may contribute to the clinical evaluation of DCM or differentiation from other diseases. Furthermore, the grading of 201Tl inhomogeneous perfusion defects related to the myocardial fibrosis of left ventricular myocardium may contribute to speculation of the myocardial degenerative stage in clinical settings. (author)

27

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)

28

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)

29

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

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/sup 201/Tl 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 /sup 201/Tl myocardial SPECT was high, and /sup 201/Tl myocardial SPECT is a useful examination to detect the change of myocardial damage in DMD. (author).

Ono, Seiji; Sugimoto, Seiichirou; Inoue, Kenjirou; Jinnouchi, Seishi; Hoshi, Hiroaki; Watanabe, Katsushi.

1989-03-01

30

Effects of ischemic-like insult on myocardial 201Tl accumulation  

International Nuclear Information System (INIS)

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

31

Two dimensional polar coordinate representation (bulls-eye view) method of the 201Tl myocardial SPECT  

International Nuclear Information System (INIS)

Two dimensional polar coordinate representation (bulls-eye view) method was applied to the 201Tl myocardial imaging by single photon emission CT (SPECT) and this method was compared with a conventional SPECT image for the ability to detect the abnormalities. We examined 5 normals and 15 patients (10 angina pectolis and 5 myocardial infarction), whose diagnosis were confirmed by coronary angiography. Diagnostic efficacy of two methods was evaluated in two groupes of radiologists by means of ROC (receiver operating characteristic) curve. Radiologists in A group have three years experience or more in nuclear medicine and those in B group have less than one year experience. As a result, diagnostic accuracy of conventional method was 93 % in a group and 55 % in B group. The accuracy by the two polar coordinate representation was increased from 55 % to 86 % in B group, although no remarkable improvement was seen in the accuracy (90 %) of A group. The consuming time for diagnosis was shortend by using the two dimensional polar coordinate representation method, especially in B group. This result suggests that the two dimensional polar coordinate representation method is useful for reading the myocardial imaging in not-well trained radiologists as well as in the well trained. (author)

32

Correlation of an abnormal rest 201Tl myocardial image: Pathological findings in cardiac transplant recipients  

International Nuclear Information System (INIS)

Rest myocardial 201Tl scintigraphy was undertaken in 15 males mean age 39 years (22-54) who had been accepted for cardiac transplantation. Complete pathological correlation was obtained in 14 after transplantation and in 1 who died before a suitable donor heart became available. The average time from scintigraphy to pathological evaluation was 42 days (9-103). All the 201Tl images were grossly abnormal and on the basis of these studies it was not possible to differentiate ischemic from idiopathic cardiomyopathy. Each of the three views of the 201Tl study was divided into three segments, therefore 135 areas were available for comparison (3 x 3 x 15). Eighty-eight of these were abnormal on scan and 78 of these were abnormal pathologically. The right ventricle was seen on all rest images but the degree of uptake bore no relationship to the measured thickness of the right ventricular wall. Structures such as the atrial wall and the enlarged papillary muscle were visualized in some patients. In two patients there was an improvement of the rest 201Tl image in delayed views and histologically these areas showed a mixture of muscle and fibrous tissue. The sensitivity of 201Tl imaging in this study was 89% and there was close correlation of the images with gross and microscopic pathological findings. (orig.)

33

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 method for identifying coronary stenosis in children with Kawasaki disease

34

The role of 201Tl SPECT in detecting myocardial viability in patients undergoing trans-myocardial laser revascularization  

International Nuclear Information System (INIS)

Objective: To evaluate the value of detecting viable myocardium by 201Tl SPECT myocardial imaging in trans-myocardial laser revascularization (TMLR). Methods: 19 patients with prior myocardial infarction and unstable angina confirmed by coronary angiography underwent TMLR. Before TMLR, dipyridamol stress test (ST)-'redistribution' (RD)-nitroglycerin (NTG) infusion re-injecting (NTG+RI)201Tl SPECT myocardial imaging were performed on all 19 patients. Of 56 segments of left ventricle with myocardial ischemia or infarction found by 201Tl SPECT imaging, 45 segments (physicians' decision) underwent TMLR using a high energy (800 W) CO2 laser. TMLR was performed on the free walls of the left ventricle of the beating heart. The average numbers of trans-myocardial channels on various segments were: 8.3 +- 2.9 on anterior wall, 6.5 +- 2.5 on lateral wall, 5.4 +- 2.0 on inferior wall, 5.3 +- 4.4 on apex. 3, 6 to 12 months after TMLR, ST-RD-NTG+RI 201Tl SPECT imaging was repeated in 19 patients, and then followed up for 3 months in 17 cases, 6 months in 11 cases, 1 year in 5 cases. Results: Of 45 segments which had TMLR, 18 segments (40%) showed improved perfusion of myocardium. Of 18 segments showed marked redistribution before TMLR, 14 segments (77.8%) were improved in myocardial perfusion after TMLR. All of 8 segments showed marked redistribution in RD imaging before TMLR showed improved myocardial perfusion after TMLR. Amproved myocardial perfusion after TMLR. Among 27 segments without redistribution in RD-NTG+RI 201Tl myocardial imaging, only 4 segments (14.8%) showed improved perfusion after TMLR. Conclusions: Stress test-redistribution-NTG infusion + reinjection 201Tl myocardial imaging is a valuable procedure to select patients for TMLR and to evaluate results of TMLR therapy

35

Evaluation of early myocardial ischemia with 201Tl in the pig  

International Nuclear Information System (INIS)

Thallium-201 was found to be a reliable agent for detecting decreased myocardial perfusion in domestic pigs 1 to 4 hours after acute coronary occlusion. Substantial variation in myocardial-to-liver count ratios and diagnostic quality was observed in serial images performed in 3 normal pigs, although areas of 1 to 4 hours-old myocardial ischemia produced by acute circumflex coronary artery ligation in 6 pigs could be reliably detected by in vivo 201Tl imaging. After intravenous 201Tl administration, the animals were sacrificed and sections of normal and ischemic myocardium were counted in a scintillation well counter. The activity in the ischemic area in pigs averaged 12% of the activity in the normal area, and varied over a narrow range; in dogs the activity averaged 62% of normal, and varied over a wide range. The pig was a more consistent model than the dog

36

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

International Nuclear Information System (INIS)

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

37

Evaluation of role of 201Tl myocardial perfusion scintigraphy in patients with left ventricular dysfunction  

International Nuclear Information System (INIS)

A study was undertaken to determine prognostic value of thallium-201 myocardial perfusion SPECT study in patients with low left ventricular dysfunction (LVEF) to predict future adverse cardiac outcome. The study shows that in patients with low LVEF the infarct size and pulmonary uptake of 201Tl are the most important prognostic indicators. Patients with mild to moderate infarct size and absent pulmonary uptake may benefit from a non invasive strategy and may not require invasive management

38

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

International Nuclear Information System (INIS)

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

39

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

International Nuclear Information System (INIS)

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

40

/sup 201/Tl chloride scintiscanning in myocardial infarction - correlation with ECG findings - diagnostic potential  

Energy Technology Data Exchange (ETDEWEB)

The author intended to find out in how far myocardial scintiscanning with /sup 201/Tl chloride is a necessary auxiliary investigation in diagnosing acute myocardial infarction and whether there are correlations between ECG, increase of enzyme levels, and pressure measured in the lesser circulatory system. The scintiscans were evaluated by a new method: Defect sizes were determined using a transparent template and recorded in angular degrees. Also the reduced activity was considered. Especially posterior myocardial infarctions can be localized more easily and clearly by means of myocardial scintiscanning at rest, and also infarction sizes can be judged more easily. For a diagnosis of small myocardial infarctions or in patients with a block in their ECG picture, scintiscanning is a necessary part of the diagnostic spectrum. The findings of myocardial scintiscanning correspond well with those of other methods. As for the pressure increase in the lesser circulatory system, it is well correlated with the defect size shown by the scintiscan. /sup 201/Tl scintiscanning offers a good diagnostic possibility in those myocardial infarctions where ECG findings are ambiguous.

Kostka, I.

1980-10-17

 
 
 
 
41

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)

42

201Tl myocardial imaging in patients with pulmonary hypertension  

International Nuclear Information System (INIS)

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

43

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)

44

Scintigraphically determined myocardial blood flow by means of 201Tl in single and multiple vascular lesions  

International Nuclear Information System (INIS)

100 patients with suspected coronary heart disease were examined for local storage defects in Tl scintigram in order to determine the clinical importance of 201Tl myocardial scintigraphy in comparison to heart catheterization. As to the sensitivity Tl scintigraphy proved to be superior to exercise electrocardiography with 89.3% to 63.6%. Tl scintigraphy was 100% sensitive in cases with 1 or 2 vessels affected compared to ECG with 47.0% and 58.8% resp. In patients with 3 vessels affected the sensitivity of both the methods was nearly equal. The myocardial scintigraphy, however, revealed more false positive results than ergometry. In spite of the diagnostic advantage, myocardial scintigraphy is not suited for screening tests. The range of indication of Tl scintigraphy in suspected as well as in established coronary heart disease is discussed

45

Radiation exposure around patients after {sup 201}Tl-myocardial scintigraphy; Strahlenexposition in der Umgebung von Patienten nach {sup 201}Tl-Myokardszintigraphie  

Energy Technology Data Exchange (ETDEWEB)

Aim: It was the aim of the study to assess the additional radiation exposure to patients, attendents and nurses by patients who are undergoing nuclear medicine investigations (myocardial scintigraphy) with {sup 201}Tl-chloride ({sup 201}Tl-Cl). Methode: In 16 cases the dose rates at 0.5, 1 and 2 m distance from patients were measured at 0.5, 1.5, 3-4 and 24, in some cases until 370 h after administration of 100{+-}10 MBq {sup 201}Tl-Cl. From the time courses of the dose rates around the patients the possible radiation exposure of other persons were estimated. Results: The initial values of the dose rate were 3.82 {mu}Sv/h at 0.5 m, 1.18 {mu}Sv/h at 1 m and 0.30 {mu}Sv/h at 2 m distance from the patients respectively. The dose rates were decreasing following a monoexponential course with an effective half-life of 60 h. The maximum doses to other persons at 1 m distance from the patients were determined by considering three scenarios. The values were 13 {mu}Sv in the waiting room, 26 {mu}Sv for nurses working in the ward and 105 {mu}Sv for persons living in the same household. Conclusion: Even at very restrictive assumptions the doses were far below the maximum permissible dose to non-radiation workers set by radiation protection regulations (1.5 mSv per year). (orig.) [Deutsch] Ziel: Es war die Absicht der Studie festzustellen, in welchem Ausmass Patienten, Begleitpersonen bzw. Pflegepersonal einer zusaetzlichen externen Strahlenexposition durch Patienten ausgesetzt sein koennen, denen zum Zweck nuklearmedizinischer Untersuchungen (Myokardszintigraphien) {sup 201}Tl-Chlorid ({sup 201}Tl-Cl) verabreicht wurde. Methode: Bei 16 Patienten, denen 100{+-}10 MBq {sup 201}Tl-Cl appliziert wurde, wurden in 0,5, 1 und 2 m Entfernung die Dosisleistungen 0,5, 1,5, 3-4 und 24, bei mehreren Patienten auch bis zu 370 h nach Applikation gemessen. Aus dem zeitlichen Verlauf der Dosisleistungen wurde die moegliche Strahlenexposition anderer Personen in der Umgebung der `strahlenden` Patienten abgeschaetzt. Ergebnisse: Die Ausgangswerte der Dosisleistung betrugen in 0,5 m Entfernung von den Patienten 3,82 {mu}Sv/h, in 1 m 1,18 {mu}Sv/h und in 2 m 0,30 {mu}Sv/h. Diese Dosisleistungen nahmen nach einer monoexponentiellen Funktion mit einer effektiven Halbwertzeit von 60 h ab. Anhand von Fallbeispielen wurde ermittelt, dass die maximale Dosis fuer andere Personen in 1 m Entfernung 13 {mu}Sv im Warteraum, 26 {mu}Sv fuer das Pflegepersonal auf einer Bettenstation bzw. 105 {mu}Sv fuer eine Person im gemeinsamen Haushalt sein kann. Schlussfolgerung: Selbst unter sehr restriktiven Annahmen ergeben sich Dosen, die weit unter der durch die Strahlenschutzbestimmungen festgelegte zulaessige Personendosis von 1,5 mSv pro Jahr liegen. (orig.)

Kurtaran, A. [Universitaetsklinik fuer Nuklearmedizin, Wien (Austria); Preitfellner, J. [Universitaetsklinik fuer Nuklearmedizin, Wien (Austria); Kohoutek, D. [Universitaetsklinik fuer Nuklearmedizin, Wien (Austria); Tousek, A. [Universitaetsklinik fuer Nuklearmedizin, Wien (Austria); Virgolini, I. [Universitaetsklinik fuer Nuklearmedizin, Wien (Austria); Havlik, E. [Inst. fuer Biomedizinische Technik und Physik, Wien (Austria)]|[Ludwig Boltzmann-Institut fuer Nuklearmedizin, Wien (Austria)

1997-01-01

46

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

Science.gov (United States)

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 368 000 ± 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.

Knesaurek, Karin; Machac, Josef

2000-11-01

47

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)

48

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

49

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

50

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)

51

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

International Nuclear Information System (INIS)

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

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

201Tl myocardial scintigraphy correlation with TMT and coronary angiography - a preliminary report  

International Nuclear Information System (INIS)

Full text: This study analyses 60 patients of suspected ischemic heart disease who underwent myocardial perfusion studies with 201Tl SPECT from June 1998 - September 1998. Thirty six patients were tested positive on TMT, thallium scintigraphy was positive in 21 (58%) patients and negative in 15 (41%) cases. Coronary angiography results were available in 35 patients, of which there were 5 cases with LBBB where TMT was not done due to high unpredictability. The 5 cases were tested negative, both angiographically and stress thallium showing 100% correlation. Out of remaining 30 patients, angiography was positive in 22 patients. Stress thallium was positive in 19 patients (87%). Of the 8 cases which showed normal coronary angiography, stress thallium was positive in 3 cases (13%) and negative in 5 patients (87%). Statistical analysis of this small group showed a sensitivity of 86%, specificity of 63%, false negative rate 14% and false positive rate of 37%. Overall accuracy is 80%

54

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.)

55

Quantitative evaluation of right ventricular overload in cor pulmonale using 201Tl myocardial SPECT  

International Nuclear Information System (INIS)

To determine quantitatively the discriminant and characteristics of cor pulmonale, 201Tl myocardial perfusion SPECT was performed in 16 patients with chronic obstructive pulmonary disease (COPD) and 7 with restrictive pulmonary disease (RPD). One section of the short-axis SPECT image in which the right ventricle was most clearly visualized was selected. Tl-score was defined as the ratio of the sum of counts in the region of interest (ROI) at the anterior, mid, and posterior regions of the right ventricular free wall to the sum of counts in ROI at the posterior, lateral, and anterior walls of the left ventricle, and the anterior and posterior regions of the interventricular septum. In the group of COPD patients, Tl-score was positively correlated with mean pulmonary arterial pressure (mPAP), total pulmonary vascular resistance (TPR), and arterial carbon dioxide tension (PaCO2), while it was inversely correlated with arterial oxygen tension (PaO2). However, there was no significant correlation between Tl-score and mPAP, TPR, PaCO2, and PaO2 in the group of RPD patients. In assessing pulmonary hypertension as defined by mPAP over 20 mmHg, a Tl-score greater than 0.25 was useful with a sensitivity of 69% and a specificity of 90%. The occurrence of cor pulmonale is a major factor in determining the prognosis of COPD patients. It was concluded that 201Tl myocardial SPECT is useful for evaluating right ventricular overload quantitatively, as well as for assessing core pulmonale, especially in COPD patients, since the ratio of Tl counts in the right and left ventricles was significantly correlated with right cardiopulmonary hemodynamic parameters. (N.K.)

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

201-Tl myocardial scintigraphy using SPECT. Clinical evaluation based on the Bayes' theorem  

International Nuclear Information System (INIS)

The results of 201-Tl myocardial scintigraphy using SPECT were analyzed by means of the Bayes' theorem with respect to the positive and negative predictive value. A first evaluation was performed on a case by case basis with respect to the decision coronary heart disease (CHD) yes or no comprising the total number of patients. Furthermore two subgroups were formed a) patients with myocardial infarction or b) without. In the second part segmental findings of the leftventricular myocardium were analyzed applying the same subdivision. The values of the post-test-probability were calculated and plotted as a function of 2 parameters: 1) the pre-test-probability and 2) the outcome of the test. The maximum of the probability-difference-curve and thus the highest gain in diagnostic information was achieved with positive test results for medium pre-test-probability (about 50%). A prefered application of myocardial scintigraphy using SPECT therefore is the diagnosis of patients with a medium pre-test-probability of CHD as well as therapy planning and follow-up. (orig.)

58

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

59

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

International Nuclear Information System (INIS)

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

60

Coronary artery disease detected noninvasively by dipyridamole-loading 201Tl myocardial scintigraphy in elderly patients  

International Nuclear Information System (INIS)

To evaluate the usefulness in diagnosing coronary artery disease (CAD), dipyridamole-loading 201Tl myocardial scintigraphy was performed for 52 elderly patients (65 - 92 years, mean: 72 years), and the results were compared with data from the treadmill exercise tests. 1. Thirty-five patients could not tolerate adequate exercise tests. Seven of them had reversible defects; six, fixed (irreversible) ones. Dipyridamole scintigraphy is therefore applicable in detecting CAD among patients with suspected CAD who are unable to perform adequate exercise tests. 2. Four of 16 patients with positive exercise tests had no reversible defects; the exercise results in three were regarded as false positives. 3. Seventeen patients experienced chest pain; 12 had ST depression during dipyridamole loading. There were no serious complications, but seven patients required aminophylline. 4. We demonstrated previously that the sensitivity and specificity of dipyridamole scintigraphy in detecting CAD were 90 % and 92 %, respectively, in patients with chest pain undergoing coronary angiography. These results were superior to those of conventional exercise myocardial scintigraphy. Therefore, dipyridamole scintigraphy is regarded as a safe and useful method for detecting CAD, particulary in elderly patients who have ST and T wave abnormalities but cannot tolerate exercise test adequately. (author)

 
 
 
 
61

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.)

62

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

63

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)

64

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% in women) Conclusion: These normal limits can be evaluated prospectively for their potential clinical value

65

Transmission scanning for attenuation correction of myocardial 201Tl images in obese patients.  

Science.gov (United States)

For attenuation correction (AC) of 201Tl myocardial perfusion images, an accurate attenuation map is required. This study assessed whether prolonged transmission scanning is required in obese compared to normal-sized patients. Twenty-nine obese patients (mean body mass index 33 kg m-2) underwent sequential emission/transmission imaging for AC using an L-shaped, dual-headed gamma camera fitted with two 153Gd scanning line sources. Transmission data were acquired for 5 s per view (scan time for normal-sized patients) and for 10 s per view and used to reconstruct individual attenuation maps. Emission data were reconstructed using each attenuation map in turn to produce attenuation-corrected images (AC5 and AC10). Tracer distribution in the AC5 and AC10 images was compared by two observers blinded to study type. For each data set, count density was measured in 17 segments of a polar plot and segmental uptake expressed relative to study maximum. Although myocardial count density was low on the 5 s per view transmission images (0.5-13.0 and 3.0-14.0 counts per pixel in the anteroposterior and lateral projections respectively), no significant differences in tracer distribution were seen between the AC5 and AC10 images and these were reported identically. In addition, the mean segmental relative uptake values were similar (P > 0.05) for corresponding segments of the AC5 and AC10 images. We conclude that prolonged transmission scanning is not required in obese compared to normal-sized patients. The transmission scanning protocol used in normal-sized patients is applicable across a wide patient weight range. PMID:9106774

Prvulovich, E M; Lonn, A H; Bomanji, J B; Jarritt, P H; Ell, P J

1997-03-01

66

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  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-08-01

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

Comparison of myocardial 201Tl clearance after maximal and submaximal exercise: implications for diagnosis of coronary disease: concise communication  

International Nuclear Information System (INIS)

Recently the quantitation of regional 201Tl clearance has been shown to increase the sensitivity of the scintigraphic detection of coronary disease. Although 201Tl clearance rates might be expected to vary with the degree of exercise, this relationship has not been explored. We therefore evaluated the rate of decrease in myocardial 201Tl activity following maximal and submaximal stress in seven normal subjects and 21 patients with chest pain, using the seven-pinhole tomographic reconstruction technique. In normals, the mean 201Tl clearance rate declined from 41% +/- 7 over a 3-hr period with maximal exercise to 25% +/- 5 after 3 hr at a submaximal level (p less than 0.001). Similar differences in clearance rates were found in the normally perfused regions of the left ventricle in patients with chest pain, depending on whether or not a maximal end point (defined as either the appearance of ischemia or reaching 85% of age-predicted heart rate) was achieved. In five patients who did not reach these end points, 3-hr clearance rates in uninvolved regions averaged 25% +/- 2, in contrast to a mean of 38% +/- 5 for such regions in 15 patients who exercised to ischemia or an adequate heart rate. These findings indicate that clearance criteria derived from normals can be applied to patients who are stressed maximally, even if the duration of exercise is limited, but that caution must be used in interpreting clearance rates in those whn interpreting clearance rates in those who do not exercise to an accepted end point

69

Diagnostic reliability of 201Tl myocardial emission computed tomography and Frank vectorcardiography for evaluation of myocardial infarct sites  

International Nuclear Information System (INIS)

Diagnostic reliability of 201Tl emission computed tomography (ECT) and vectorcardiography (VCG) for evaluation of myocardial infarction (MI) was studied comparatively in 64 patients with prior myocardial infarction (group I) and 41 noninfarction patients with electrocardiographic abnormalities simulating infarction (group II). The left ventricular wall was divided into anterior, septal, lateral, inferior, and posterior segments in the left ventriculogram. Based on the number of its akinetic segments, group I was divided into two subgroups, solitary infarct group (I-a; n = 48) and multiple infarct group (I-b; n = 16). In group I-a, both ECT and VCG showed a good diagnostic accuracy for every LV segment. In group I-b, ECT showed high sensitivity for all LV segments, whereas VCG showed lower one for the posterior and inferior than for the septal, anterior and lateral segments. In group II, 25 patients satisfied VCG criteria for myocardial infarctions, whereas only two met ECT criteria for myocardial infarction. The latter revealed malrotation of cardiac axis in 13 cases (32 %). Low sensitivity of VCG for multiple infarcts may be best explained by cancellation effects of multiple, reciprocal infarction vectors. Either cardiac malrotation and/or malposition may cause VCG findings simulating myocardial infarction. (author)

70

Low-dose single acquisition rest 99mTc/stress 201Tl myocardial perfusion SPECT protocol: phantom studies and clinical validation  

International Nuclear Information System (INIS)

We developed and tested a single acquisition rest 99mTc-sestamibi/stress 201Tl 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 99mTc and rest 99mTc 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 201Tl dose of 74 MBq was insufficient for clinical assessment. In answer to this the 201Tl dose was adapted for obese patients in the rest of the study. In 31 patients, SDI and 99mTc 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 99mTc 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.)

71

Combined scatter and attenuation correction for {sup 201}Tl myocardial perfusion SPECT using OS-EM algorithm  

Energy Technology Data Exchange (ETDEWEB)

There are two possible ways to obtain scatter-corrected images with the ML-EM (maximum likelihood expectation maximization) algorithm: one is the subtraction of scatter estimate Si from projection data pi, and then (pi-si) is used for scatter-corrected projection data (denoted as SC(T)); the other method is the addition of scatter estimate si to the projections calculated from the reconstructed image without performing data subtraction (SC(E)). This paper investigated these two ML-EM algorithms of combined scatter and attenuation correction on {sup 201}Tl myocardial perfusion SPECT imaging. Scatter windows were placed one full width at half maximum (FWHM) below and above the photopeak centerline. The scatter fraction in the primary peak was estimated using trapezoidal approximation by the triple energy window method. Phantom and clinical images were reconstructed using 6 iterations of ordered subsets EM algorithm (OS-EM). A cylindrical phantom with a cold-rod insert and a heart/thorax phantom with liver insert were used to evaluate scatter and the attenuation compensation technique. A cylindrical phantom filled with uniform {sup 201}Tl solution was used to evaluate statistical noise. The percent root-mean-square uncertainly (%RMSU) was used as a quantitative measure of noise amplification. %RMSU showed that the SC(E) method amplified noise less in comparison with the SC(T) method, however, no significant difference in image quality was observed between the two methods. In conclusion, both the SC(T) and SC(E) methods provided significant and similar improvement in the removal of scatter in {sup 201}Tl myocardial perfusion SPECT imaging. (author)

Matsuoka, Shin; Shinohara, Hiroyuki; Yamamoto, Tomoaki [Showa Univ., Yokohama (Japan). Fujigaoka Hospital] [and others

1998-11-01

72

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-11-01

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 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 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

Quantitative assessment of myocardial blood flow by measurement of fractional myocardial uptake of 201Tl  

International Nuclear Information System (INIS)

als (1.75 +- 0.11). MBF/CO increased proportionally to the increment of the double product of heart rate and systolic blood pressure by exercise loading in normals, whereas it didn't in CAD. The sensitivity of this method was superior to the stress electrocardiogram and the stress myocardial perfusion imaging, not only in CAD II but also in CAD I. This result indicated that this type of global assessment of the myocardial reserve capacity is valuable in addition to the simple stress myocardial perfusion imaging. (author)

77

Delayed cerebral radionecrosis with a high uptake of {sup 11}C-methionine on positron emission tomography and {sup 201}Tl-chloride on single-photon emission computed tomography  

Energy Technology Data Exchange (ETDEWEB)

A 47-year-old woman, who 2.5 years previously had undergone resection of a malignant astrocytoma of the left temporal lobe followed by radiotherapy, was found to have a mass in the left frontal lobe. This showed high uptake of thallium-201 ({sup 201}Tl) on single-photon emission computed tomography and {sup 11}C-methionine on positron-emission tomography, suggesting recurrent tumour. Histological examination of the resected lesion, however, revealed it to be radionecrosis. This case thus illustrates a diagnostic pitfall in the use of these investigations for distinguishing radionecrosis from recurrent malignant glioma. (orig.) With 2 figs., 21 refs.

Tashima, T.; Hachisuga, S. [Department of Neurosurgery, Hachisuga Hospital, Munakata (Japan); Morioka, T.; Nishio, S.; Fukui, M. [Department of Neurosurgery, Faculty of Medicine, Kyushu University, Fukuoka (Japan); Sasaki, M. [Department of Radiology, Faculty of Medicine, Kyushu University, Fukuoka (Japan)

1998-07-01

78

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

International Nuclear Information System (INIS)

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

79

Lung uptake of 201Tl in myocardial stress imaging: correlation with echocardiographic and scintigraphic variables of myocardial ischaemia.  

Science.gov (United States)

The lung uptake of thallium-201 (201Tl) in planar imaging was evaluated in 384 patients enrolled in the SIRT study (Italian Multicentre Study on Thallium Reinjection). All patients underwent treadmill exercise, and at peak exercise 74 MBq of 201TI were injected. The patients were then evaluated after reinjection of 201Tl under baseline conditions. The left ventricle was subdivided into 16 echocardiographic and 15 scintigraphic segments. The best correlates of visually scored 201Tl lung uptake, of the lung heart ratio and lung wash-out were checked. The independent variables entered in the stepwise multiple-regression analysis were: the echocardiographic wall motion index, the scintigraphic perfusion score index, and the number of segments that improved by at least 1 and 2 grades after redistribution and after reinjection. We concluded that the lung:heart ratio and, in particular, lung wash-out do not correlate more closely than the visual score with the variables taken into consideration. This suggests that visually scored lung uptake of 201Tl is still of value in nuclear cardiology practice. The scintigraphic variables associated with reinjection do not seem to offer any additional information with respect to redistribution variables. We also analysed the impact on 201Tl lung uptake of several other index variables. Student's t-test revealed that no single variable significantly alters lung uptake after stress testing. PMID:7491177

Chiti, A; Brambilla, M; Inglese, E; Tarolo, G L

1995-08-01

80

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.)

 
 
 
 
81

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 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)

82

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

Energy Technology Data Exchange (ETDEWEB)

{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

201Tl-myocardial SPECT - first experiences with a simultaneous transmission emission acquisition for non-uniform patient-related attenuation correction  

International Nuclear Information System (INIS)

In this study our first clinical experiences with simultaneous transmission and emission acquisition in 201Tl myocardial SPECT (T/E-SPECT) are discussed. The non-uniform attenuation (AK) was carried out with a triple-head camera (PRISM 3000, Picker Inc.) correction equipped with fanbeam collimators. A line source of 750 MBq 99mTc was used to construct the transmission profile. Prior to investigation patients got 80-120 MBq 201Tl-chloride intraveneously injected. The study comprises the evaluation of 40 patients, derived from the clinical routine. The investigation followed an usual one day protocol. Our results using T/E-SPECT reveal an almost equilibrated activity distribution between anterior and posterior myocardial wall. For this reason it is to be expected that T/E-SPECT provides more reliable information about the posterior myocardial wall, than the usual SPECT technique without attenuation correction. (orig./MG)

84

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

International Nuclear Information System (INIS)

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

85

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

International Nuclear Information System (INIS)

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

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

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

Energy Technology Data Exchange (ETDEWEB)

Using /sup 123/I-..omega..-heptadecanoic acid (HDA) and /sup 201/Tl, 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 /sup 201/Tl showed abnormalities in 76%. Correlations were found between decreased uptake of HDA and prolonged elimination half-life as well as defects by /sup 201/Tl, presumably due to ischemia based on small-vessel disease or abnormalities of cellular metabolism.

Voth, E.; Schicha, H.; Neumann, P.; Emrich, D.; Tebbe, U.

1987-08-01

88

Comparison study of left ventricular ejection fraction measured by 201Tl gated myocardial imaging and 99mTc-red blood cell gated blood-pool imaging  

International Nuclear Information System (INIS)

Objective: To explore the correlation of automatic quantification of left ventricular ejection fraction (LVEF) from gated myocardial perfusion SPECT with 201Tl and rest equilibrium gated blood- pool imaging with 99mTc-red blood cell. Methods: Rest gated myocardial perfusion SPECT with 201Tl was performed on 72 cases. AUTOQUANT 4.21 software was used to measure LVEF. Rest equilibrium gated blood-pool imaging was also performed within 24 h. The values of LVEF measured by two methods were calculated and compared. Results: (1)There were strong correlation between the LVEF measured by rest gated myocardial perfusion SPECT and rest equilibrium gated blood-pool imaging(r=0.554, P=0.000). There was no significant difference between the two methods (t=1.194, P>0.05). (2) There was no significant difference between the two methods among different disease groups. (3) The values of LVEF measured by two methods were (64.68 ± 10.77)% and (62.46±8.99)%. The values of LVEF measured by gated myocardial perfusion SPECT was higher 3.55% than rest equilibrium gated blood-pool imaging. Conclusion: There was good correlation between the LVEF measured with gated myocardial perfusion SPECT by AUTOQUANT 4.21 software and gated blood-pool imaging. The LVEF can be accurately evaluated using gated myocardial perfusion SPECT with 201Tl. The value of LVEF measured by gated myocardial perfusion SPECT was higher than rest equilibrium gated blood-pool imaan rest equilibrium gated blood-pool imaging. (authors)

89

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

International Nuclear Information System (INIS)

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

90

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)

91

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

International Nuclear Information System (INIS)

oss 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)

92

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

93

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)

94

Lung activity in [sup 201]Tl-myocardial scintigraphy: Distribution and correlation with hemodynamic parameters. Die Lungenaktivitaet in der [sup 201]Tl-Myokardszintigraphie: Verteilung und Korrelation zu haemodynamischen Parametern  

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The aim of this study was 1. to investigate whether the pulmonary activity in [sup 201]Tl 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 (HR[sub ex]) exhibit the strongest relation to LHR. After correction with regard to HR[sub ex] the elevated LHR points to a pathological LVEF during exercise. (orig.)

Richter, W.S. (Freie Universitaet Berlin, Strahlen- und Poliklinik, Berlin (Germany)); Barzen, G. (Freie Universitaet Berlin, Strahlen- und Poliklinik, Berlin (Germany)); Siekmann, R. (Freie Universitaet Berlin, Strahlen- und Poliklinik, Berlin (Germany)); Jochens, R. (Freie Universitaet Berlin, Strahlen- und Poliklinik, Berlin (Germany)); Calder, D. (Freie Universitaet Berlin, Strahlen- und Poliklinik, Berlin (Germany)); Cordes, M. (Freie Universitaet Berlin, Strahlen- und Poliklinik, Berlin (Germany)); Felix, R. (Freie Universitaet Berlin, Strahlen- und Poliklinik, Berlin (Germany))

1994-06-01

95

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

International Nuclear Information System (INIS)

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

96

Effect of long-term cholesterol-lowering treatment with HMG-CoA reductase inhibitor (Simvastatin) of myocardial perfusion evaluated by thallium-201 single photon emission computed tomography  

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Fifteen patients with either angina pectoris or old myocardial infarction, who had positive {sup 201}Tl single photon emission computed tomography (SPECT) imaging and coronary sclerosis of more than 50%, were treated with an HMG-CoA reductase inhibitor (simvastatin) for more than 1 year. They were compared with an untreated control group (n=25). Total cholesterol decreased 22% and high-density lipoprotein (HDL) increased 9% with simvastatin; both changes were significantly different from those in controls. Long-term simvastatin induced improvement of myocardial perfusion on {sup 201}Tl SPECT images both during exercise and at rest, which was also significantly different from controls. In addition, the improvement of myocardial perfusion on {sup 201}Tl SPECT images was clearly related to the improvements in cholesterol values, especially nonHDL cholesterol. Thus, the greater the decrease in nonHDL cholesterol, the greater the improvement in myocardial perfusion at rest or during exercise with long-term treatment using an HMG-CoA reductase inhibitor. These findings indicate that the improvements in cholesterol values caused by HMG-CoA reductase inhibitor therapy are related to improvements of myocardial perfusion seen on {sup 201}Tl SPECT images. (author)

Hosokawa, Ryohei; Nohara, Ryuji; Linxue, Li; Sasayama, Shigetake [Kyoto Univ. (Japan). Graduate School of Medicine; Tamaki, Shunichi; Hashimoto, Tetsuo; Tanaka, Masahiro; Miki, Shinji

2000-03-01

97

Effect of long-term cholesterol-lowering treatment with HMG-CoA reductase inhibitor (Simvastatin) of myocardial perfusion evaluated by thallium-201 single photon emission computed tomography  

International Nuclear Information System (INIS)

Fifteen patients with either angina pectoris or old myocardial infarction, who had positive 201Tl single photon emission computed tomography (SPECT) imaging and coronary sclerosis of more than 50%, were treated with an HMG-CoA reductase inhibitor (simvastatin) for more than 1 year. They were compared with an untreated control group (n=25). Total cholesterol decreased 22% and high-density lipoprotein (HDL) increased 9% with simvastatin; both changes were significantly different from those in controls. Long-term simvastatin induced improvement of myocardial perfusion on 201Tl SPECT images both during exercise and at rest, which was also significantly different from controls. In addition, the improvement of myocardial perfusion on 201Tl SPECT images was clearly related to the improvements in cholesterol values, especially nonHDL cholesterol. Thus, the greater the decrease in nonHDL cholesterol, the greater the improvement in myocardial perfusion at rest or during exercise with long-term treatment using an HMG-CoA reductase inhibitor. These findings indicate that the improvements in cholesterol values caused by HMG-CoA reductase inhibitor therapy are related to improvements of myocardial perfusion seen on 201Tl SPECT images. (author)

98

Diagnosis of effort angina pectoris using 201Tl stress myocardial imaging  

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Tl-201 stress myocardial SPECT images were obtained from 42 patients with effort angina pectoris and 40 healthy volunteers. Predicted washout rate (WR) was calculated from the regression equation of the maximum heart rate in normal volunteers. In determining ischemic areas, the sensitivity and specificity of predicted WR were 69%-81% and was 86%, respectively, for the left anterior descending artery; 54%-79% and 84%-92% for the right coronary artery; and 60%-68% and 86%-91% for the left circumflex artery. In evaluating the number of diseased coronary arteries, the accuracy of predicted WR was significantly higher than that of conventional mean WR (78% vs 50% for single vessel disease; 60% vs 46% for two-vessel disease). For three-vessel disease, predicted WR had the same accuracy as mean WR (57%). The results indicate the validity of using predicted WR in the quantitative evaluation of stress myocardial SPECT images. (Namekawa, K)

99

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

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We investigated retrospectively the clinical significance of large perfusion defect on {sup 201}Thallium 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) (P<0.001). Analyzing patients with ischemic heart disease (IHD; angina pectoris and myocardial infarction) according to the severity of coronary artery lesion, the proportion of cases with large perfusion defect was significantly larger than that of cases with small perfusion defect in 3 vessel disease (P<0.001). Incidence of diabetes mellitus was significantly higher in patients with IHD than in those with MD in large perfusion defect group (P<0.01). As for symptoms in large perfusion defect group, the incidences of chest pain, chest oppression, and chest discomfort were significantly higher in patients with IHD than in those with MD (P<0.001), whereas the incidences of palpitation and shortness of breath were significantly higher in patients with MD (P<0.001). These results suggest that IHD with multiple artery lesions and MD underlie large perfusion defect on {sup 201}Thallium myocardial scintigraphy and that complication of diabetes mellitus and clinical symptoms may be useful in differentiating IHD from MD. (author)

Morota, Motoi; Kobayashi, Yasuhiko [Tokyo Medical Coll. (Japan)

1999-02-01

100

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

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

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

1989-03-01

 
 
 
 
101

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)

102

sup 99m Tc-Isonitrile ('MIBI'): Chances to improve myocardial scintigraphy or substitute for sup 201 Tl. sup 99m Tc-Isonitril ('MIBI'): Chancen zur Verbesserung der Myokardszintigraphie oder Ersatz fuer sup 201 Tl  

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

Hoer, G.; Bittner, G.; Standke, R.; Maul, F.D.; Klepzig, H. Jr.; Baum, R.P. (Frankfurt Univ. (Germany, F.R.). Abt. fuer Nuklearmedizin; Frankfurt Univ. (Germany, F.R.). Abt. fuer Kardiologie)

1989-04-01

103

Importance of 201Tl scintigraphy during exercise for diagnosis of silent myocardial ischemia  

International Nuclear Information System (INIS)

Using thallium scintigraphy during exercise (TSE), suspect silent myocardial ischemia (SIM) was diagnosed in subjects without angina pectoris. 21 active pilots with suspect SIM were examined after previous exercise ECG as well as 33 patients with diabetes type I and II. In six pilots (28.6%) TSE showed accumulation defects suggesting ischemic disorders of the large coronary arteries. Five pilots showed obvious depressions of the ST segment in ECG during submaximal exercise TSE. In another group of five pilots small depressions of the ST segment were associated with normal TSE. Twelve diabetic patients (36.4%) had minor accumulation defects on TSE. Only two showed a ST depression under 2 mm in ECG during TSE. Based on data in the literature suggesting higher sensitivity and specificity of exercise thallium scintigraphy as compared with exercise ECG and the possibility of a false positive diagnosis of SIM from exercise ECG alone, it is recommended to also use TSE. A more detailed diagnosis of SIM is essential not only with regard to the assessment of work capacity but also for a long-term follow-up of patients with SIM for assessment of its incidence, impact and prognosis in the population. (author). 4 figs., 4 tabs., 25 refs

104

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

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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)

105

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

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

106

{sup 201}Tl-myocardial SPECT - first experiences with a simultaneous transmission emission acquisition for non-uniform patient-related attenuation correction; {sup 201}Tl-Myokard-SPECT - erste Erfahrungen mit einem simultanen Transmission-Emission-Akquisitionsprotokoll zur patientenspezifischen Abschwaechungskorrektur  

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In this study our first clinical experiences with simultaneous transmission and emission acquisition in {sup 201}Tl myocardial SPECT (T/E-SPECT) are discussed. The non-uniform attenuation (AK) was carried out with a triple-head camera (PRISM 3000, Picker Inc.) correction equipped with fanbeam collimators. A line source of 750 MBq {sup 99m}Tc was used to construct the transmission profile. Prior to investigation patients got 80-120 MBq {sup 201}Tl-chloride intraveneously injected. The study comprises the evaluation of 40 patients, derived from the clinical routine. The investigation followed an usual one day protocol. Our results using T/E-SPECT reveal an almost equilibrated activity distribution between anterior and posterior myocardial wall. For this reason it is to be expected that T/E-SPECT provides more reliable information about the posterior myocardial wall, than the usual SPECT technique without attenuation correction. (orig./MG) [Deutsch] In dieser Studie werden unsere ersten klinischen Erfahrungen mit der simultanen Akquisition von Transmissions- und Emissionsdaten bei der {sup 201}Tl-Myokard-SPECT (T/E-SPECT) zur nichthomogenen, patienten-spezifischen Abschwaechungskorrektur (AK) vorgestellt. Die Untersuchungen wurden mit einer Dreikopf-Rotationsgammakamera (Prism 3000, Fa. Picker) durchgefuehrt, die mit speziellen Fanbeam (Cardiofan) Kollimatoren ausgeruestet war. Das Transmissionsprofil wurde mit Hilfe einer Linienquelle, gefuellt mit 750 MBq {sup 99m}Tc, erstellt. Die Myokardszintigraphien wurden nach i.v. Applikation von 80-120 MBq {sup 201}Tl-Chlorid nach dem gaengigen Eintagesprotokoll durchgefuehrt. Die Studie umfasst die Auswertung von insgesamt 40 Patienten, die zur Abklaerung einer koronaren Herzerkrankung untersucht wurden. Als - fuer die klinische Routine massgebliches - Ergebnis zeigte sich, dass mit der Methode der T/E-SPECT eine weitgehend ausgeglichene, anatomiekonformere Aktivitaetsverteilung zwischen Herzvorderwand (VW) und -hinterwand (HW) zu erzielen ist. Damit ist zu erwarten, dass T/E-SPECT gegenueber den konventionellen Verfahren ohne Schwaechungskorrektur zu einer zuverlaessigeren Beurteilung von Hinterwandbefunden fuehrt. (orig./MG)

Knesewitsch, P. [Klinik und Poliklinik fuer Nuklearmedizin, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Walser, R. [Klinik und Poliklinik fuer Nuklearmedizin, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Kantlehner, R. [Klinik und Poliklinik fuer Nuklearmedizin, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Muenzing, W. [Klinik und Poliklinik fuer Nuklearmedizin, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Hahn, K. [Klinik und Poliklinik fuer Nuklearmedizin, Ludwig-Maximilians-Universitaet, Muenchen (Germany)

1996-06-01

107

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.)

108

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

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

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

1996-11-01

109

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)

110

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

111

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

International Nuclear Information System (INIS)

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

112

Correlation of left ventricular dyssynchrony with myocardial stunning using dual single photon emission computed tomography of 123iodine-?-methyl iodophenyl pentadecanoic acid and 201thallium scintigraphy after reperfusion therapy  

International Nuclear Information System (INIS)

Left ventricular (LV) dyssynchrony after reperfusion therapy has been closely examined as a cause of chronic remodeling, but the details have not been clarified. The present study measured LV dyssynchrony appearing immediately after reperfusion therapy using real-time three-dimensional echocardiography (RT-3DE), and assessed the significance of this phenomenon in relation to dual single photon emission computed tomography (SPECT) of 123iodine ? methyliodophenyl pentadecanoic acid (123I-BMIPP) and 201thallium (201Tl). Subjects comprised 58 patients with first-time acute myocardial infarction who received reperfusion therapy and underwent RT-3DE and dual SPECT of 123I-BMIPP and 201Tl within two weeks of onset. Two dyssynchrony parameters were measured using RT-3DE in the acute phase and six months later. After evaluating the correlation of these dyssynchrony parameters to resting 201Tl uptake, 201Tl washout, 123I-BMIPP uptake, and 201Tl-123I-BMIPP discrepancy (Tl-BMIPP discrepancy), we compared scintigraphic parameters in the chronic phase between groups with improved dyssynchrony and those without. Acute dyssynchrony exhibited a significant positive correlation to Tl-BMIPP discrepancy and it was significantly increased in the group with improved dyssynchrony in the chronic phase, revealing close relationship between dyssynchrony and Tl-BMIPP discrepancy. Then the subjects were divided into positive Tl-BMIPP discrepancy and negative discrepancy groups, and the parameters of cardiac function were compared between them. In the chronic phase, improved cardiac function was observed in the group with positive Tl-BMIPP discrepancy compared to negative discrepancy. LV dyssynchrony after reperfusion therapy correlates positively with Tl-BMIPP discrepancy, reflecting acute myocardial stunning, in which ventricular contraction improves during the chronic phase. (author)

113

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  

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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)

114

Quantitative rotational tomography with 201Tl and 99mTc 2-methoxy-isobutyl-isonitrile. A direct comparison in normal individuals and patients with coronary artery disease  

International Nuclear Information System (INIS)

We tested the hypothesis that 99mTc 2-methoxy-isobutyl-isonitrile (99mTc MIBI), a new radiopharmaceutical for myocardial perfusion imaging, provides accurate noninvasive detection of coronary artery disease (CAD). Imaging in patients after exercise and at rest with 99mTc MIBI was compared with imaging after exercise and redistribution with 201Tl in 12 normal subjects and 38 patients with angiographic documentation of CAD (greater than or equal to 50% diameter stenosis). We used single-photon emission computed tomography (SPECT) and computer quantitation of regional tracer distribution. The quality of reconstructed images with 99mTc MIBI judged visually was superior to that of 201Tl in 88% of all studies performed and was comparable in the others. With the limits of normal as 2.5 SD below the mean of gender-matched normal volunteers, 201Tl SPECT identified 32 and 99mTc MIBI identified 36 patients with CAD (p = 0.2). 201Tl SPECT identified 45 of 75 (60%) and 99mTc MIBI identified 59 of 75 (79%) stenosed coronary arteries (p less than 0.05). The quantitative severity of perfusion defects was similar for the two tracers. 201Tl SPECT identified 104 reversibly ischemic myocardial segments compared with 134 with 99mTc MIBI (p less than 0.05). Thus, SPECT myocardial perfusion imaging with 99mTc MIBI and computer quantitation provides an accurate method for the noninvasive detection of significant coronary artery disease. Furthermore, image quality is generally superior to 201Tl, and reversibly ischemic myocardial segments may be better identified with 99mTc MIBI

115

201TlCl accumulation dynamics in brain metastases after radiosurgery  

International Nuclear Information System (INIS)

We performed dynamic single-photon emission computed tomography (SPECT) with 201thallium chloride (201TlCl) before and after radiosurgery for brain metastases to assess 201TlCl accumulation after treatment. Ten lesions were studied in eight patients by dynamic SPECT before and 7 days after irradiation. Dynamic SPECT was performed for 15 min after administration of 201TlCl. Static and dynamic data were collected before and after treatment and compared. A decrease in accumulated 201TlCl was noted 7 days after treatment. A decrease in accumulated 201TlCl was noted 7 days after treatment. The thallium index (TL index) before treatment was 6.74±1.31 and had decreased considerably 7 days after radiosurgery (3.38±0.88, p201TlCl administration. After treatment, however, the reduction in accumulated 201TlCl was significant at 6 min (-0.485±0.391 counts/pixel, p201TlCl administration when compared to the first 3 min. The lower accumulated 201TlCl figures 7 days after radiosurgery were due mainly to a decrease in the retention of 201TlCl within the tumor, rather than to an early change in u rather than to an early change in uptake. These findings suggest that the early effect of radiosurgery on metastatic brain lesions is greater on the tumor cell membrane than on the blood vessels, blood flow, responsible for maintaining tumor. (author)

116

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  

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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

117

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)

118

Computer-aided semi-quantitative myocardial scintiscanning using 201-Tl in routine examinations to diagnose coronary heart disease  

International Nuclear Information System (INIS)

Thallium-201 is generally used for intravenous myocardial scintiscanning. In the 42 patients investigated during the study, the sensitivity of this method in the diagnosis of reduced myocardial perfusion was judged to be superior to that of exercise electrocardiography. The most reliable conclusions could, however, be drawn from the combined results of both these non-invasive techniques. Coronary angiography was carried out for reasons of comparison and proved that the method under investigation, even though showing an extremely high sensitivity, was less satisfactory as regards specifity. Myocardial scintiscanning using thallium-201 constitutes the only non-invasive technique suitable for the evaluation of cardial microcirculation. It must therefore be regarded as an ideal diagnostic tool to be used in combination with coronary angiography which, in turn, provides evidence of macroscopic changes. Moreover, myocardial scintiscanning using thallium-201 still remains the only procedure permitting acute myocardial infarction to be detected within the first few hours following the incident. (TRV)

119

Relation between myocardial damage and disease activity in patients with systemic lupus erythematosus by exercise {sup 201}Tl scintigraphy  

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Myocardial damage in patients with systemic lupus erythematosus (SLE) was evaluated using exercise thallium-201 myocardial scintigraphy, and the relationship between myocardial damage and disease activity of SLE was examined. Twenty-seven patients (26 women and 1 man, mean age 43 years), in whom extramural coronary artery lesions were excluded by coronary angiogram or presumed to be excluded by exercise electrocardiogram, were enrolled in this study. The mean duration of disease and the mean duration of corticosteroid therapy in these patients were 94 and 77 months, respectively. Exercise thallium-201 scintigraphy was performed twice (mean interval, 30 months) to evaluate the progression of myocardial damage. Myocardial ischemia as an index of myocardial damage was evaluated by visual analysis and ischemic score (IS). The changes in myocardial ischemia were categorized into 3 groups: improved, unchanged or worsened. The disease activity of SLE was determined by the SLE Disease Activity Index (SLEDAI), and the changes in this index were classified into the same three categories, as evaluated every six months between the two scintigraphic examinations. Disease activity was significantly correlated with myocardial ischemia (p<0.05), and with myocardial ischemia as diagnosed by {Delta}IS (difference in ischemic score between the first and second thallium-201 scintigrams: p<0.005). But neither the duration of disease nor the duration of corticosteroid therapy was correlated with IS at the first scintigraphy. These results indicate that control of SLE disease activity may be critical in the treatment of myocardial damage resulting from vascular lesions, especially intramyocardial small-artery disease, in patients with SLE. (author)

Kuzumoto, Masayuki [Nara Medical Univ. (Japan)

1997-08-01

120

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.)

 
 
 
 
121

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

International Nuclear Information System (INIS)

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

122

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

International Nuclear Information System (INIS)

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

123

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

124

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)

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

125

Comparison of adenosine and exercise stress 201Tl myocardial perfusion imaging for diagnosing coronary heart disease in women  

International Nuclear Information System (INIS)

Objective: To compare the diagnostic value of adenosine and exercise stress myocardial perfusion imaging (MPI) for detecting coronary heart disease (CHD) in women. Methods: One hundred and thirty-eight patients with CHD were randomly divided into two groups: adenosine stress group (n=69)and exercise stress group (n=69). All patients underwent myocardial SPECT evaluation. Coronary angiography (CAG), referred as 'gold standard' , was performed in each patient within 1 week before or after MPI. The diagnostic value of the two stress MPI was compared with ?2 test or Fisher's exact test. Results: In adenosine stress group, the sensitivity, negative predictive value and accuracy were 88.2% (45/51), 72.7% (16/22), 88.4% (61/69), respectively, which were not significantly different from those of the exercise stress group (91.7% (44/48), 66.7% (8/12), 81.2% (52/64); ?2 =0.571, 0.714, 0.249, P>0.05). However, the false positive rate of adenosine stress (11.1%, 2/18) was significantly lower than that of exercise stress (50.0%, 8/16), P=0.023. Conclusions: Adenosine and exercise stress MPI have similar value for CHD diagnosis in women, however, adenosine stress MPI may have an advantage of low false positive rate. (authors)

126

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.)

127

Computer-aided semi-quantitative myocardial scintiscanning using 201-Tl in routine examinations to diagnose coronary heart disease. Rechnerunterstuetzte semiquantitative 201-Tl-Myokardszintigraphie in der Roentgendiagnostik der koronaren Herzerkrankung  

Energy Technology Data Exchange (ETDEWEB)

Thallium-201 is generally used for intravenous myocardial scintiscanning. In the 42 patients investigated during the study, the sensitivity of this method in the diagnosis of reduced myocardial perfusion was judged to be superior to that of exercise electrocardiography. The most reliable conclusions could, however, be drawn from the combined results of both these non-invasive techniques. Coronary angiography was carried out for reasons of comparison and proved that the method under investigation, even though showing an extremely high sensitivity, was less satisfactory as regards specifity. Myocardial scintiscanning using thallium-201 constitutes the only non-invasive technique suitable for the evaluation of cardial microcirculation. It must therefore be regarded as an ideal diagnostic tool to be used in combination with coronary angiography which, in turn, provides evidence of macroscopic changes. Moreover, myocardial scintiscanning using thallium-201 still remains the only procedure permitting acute myocardial infarction to be detected within the first few hours following the incident. (TRV).

Schumacher, M.

1983-01-01

128

Radiomanganese for positron emission tomography: a comparative study with 201Tl-chloride  

International Nuclear Information System (INIS)

A comparative study was made of the biodistribution patterns of two myocardial imaging agents, 201Tl chloride and radiomanganese, in mice. Blood and tissue samples were collected for up to 24 hours after intravenous injection. It was concluded that sup(52m)Mn has advantages over 201Tl as a myocardial imaging agent because of its faster blood clearance and lower concentration in adjacent organs. sup(52m)Mn is suitable for myocardial imaging by positron emission tomography. (U.K.)

129

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

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Dual single photon emission computed tomography (SPECT) was performed in 30 patients with Duchenne`s muscular dystrophy (DMD) using {sup 201} thallium (Tl) for myocardial perfusion {sup 123}I-{beta}-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 myocardial metabolism of each substance thereby enabling the assessment of left ventricular function. (author).

Sasaki, Akira [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

1996-03-01

130

The white-hole phenomenon - a potential parameter of function in non-gated [sup 201]Tl myocardial scintigraphy. Das 'white hole'-Phaenomen - ein moeglicher Funktionsparameter der ungetriggerten [sup 201]Tl-Myokardszintigraphie  

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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 [sup 221]TI-SPECT is an easy-to-determine additional parameter which allows an at least semiquantitative statement about the function of the left ventricle. (orig.)

Horn, H. (Klinik fuer Nuklearmedizin, Ulm Univ. (Germany) Klinik fuer Nuklearmedizin, Kiel Univ. (Germany)); Magerle, R. (Klinik fuer Nuklearmedizin, Ulm Univ. (Germany) Klinik fuer Nuklearmedizin, Kiel Univ. (Germany)); Clausen, M. (Klinik fuer Nuklearmedizin, Ulm Univ. (Germany) Klinik fuer Nuklearmedizin, Kiel Univ. (Germany)); Weller, R. (Klinik fuer Nuklearmedizin, Ulm Univ. (Germany) Klinik fuer Nuklearmedizin, Kiel Univ. (Germany)); Henze, E. (Klinik fuer Nuklearmedizin, Ulm Univ. (Germany) Klinik fuer Nuklearmedizin, Kiel Univ. (Germany))

1993-02-01

131

Assessment of glioma viability by estimating 201Tl SPET tumour uptake volume.  

Science.gov (United States)

The aim of this study was to develop a quantitative method to assess viable tumour based on post-operative 201Tl single photon emission tomography (SPET). We studied 15 patients with histologically defined highly malignant gliomas in the post-operative phase before initiation of adjuvant treatment. A 201Tl index was calculated in two ways: maximal counts versus mean counts within a region of interest (ROI). The tumour uptake volume (TUV) within the lesion was calculated from the number of voxels that had 201Tl uptake above a threshold calculated from the uptake on the contralateral side. The threshold was set at three levels: A = 1.4 times the mean 201Tl uptake in a three-dimensional reference ROI + 96.7% confidence interval (the TUV was corrected by subtraction of the volume in the reference ROI that had uptake above the threshold with compensation for unequal ROI sizes); B = 1.4 times the mean reference ROI + 99% confidence interval; and C = maximum 201Tl uptake in the reference ROI. The SPET results were compared with the tumour volumes calculated from CT scans. Thirteen tumours showed high post-operative 201Tl uptake. The 201Tl index was not significantly correlated with histological grade within the group of highly malignant gliomas. 201Tl SPET tumour uptake volume method B was highly significantly correlated with CT estimated tumour volume. In conclusion, the measurement of post-operative 201Tl SPET tumour uptake volume demonstrates metabolically active glioma tissue and is an alternative method for the monitoring of glioma treatment response. PMID:10533190

Källén, K; Geijer, B; Andersson, A M; Holtås, S; Ryding, E; Rosén, I

1999-09-01

132

Clinical validation of simultaneous dual-isotope myocardial scintigraphy  

International Nuclear Information System (INIS)

Simultaneous dual-isotope (rest thallium-201/stress technetium-99m sestamibi) myocardial single-photon emission tomography (SPET) would be an ideal procedure; however, 99mTc cross-talk on the 201Tl window hampers its routine use. Photon energy recovery (PER) is a spectral deconvolution technique validated for scatter and cross-talk removal in phantom studies and a limited series of patients. In this study we aimed to validate the technique in 295 patients within a context of clinical routine practice. Conventional separate rest 201Tl myocardial SPET data sets were visually compared with simultaneous dual-isotope data sets corrected by PER. Conventional separate rest 201Tl data sets were identical to dual PER-corrected 201Tl data sets in 173 (58.6%) patients. As dual PER 201Tl data sets are corrected for 99mTc cross-talk but also for 201Tl scatter, they were compared with separate rest 201Tl data sets corrected by PER in the 122 discordant patients. No difference was found in 77 (26.1%) patients. In 26 (8.8%) patients, the difference consisted in the presence of a defect on dual PER 201Tl data sets only, mirroring an ischaemic defect on 99mTc-sestamibi data sets. This difference can be attributed to the influence of stress on the kinetics of 201Tl injected at rest. In the remaining 19 (6.4%) patients, the difference between separate and simultaneous PER-corrected data sets was scored as mild in 11 and moderate in eight patients and seemed to be related to multiple methodological factors. It is concluded that PER correctly removes 99mTc cross-talk. With the addition of an appropriate attenuation correction, the PER technique may allow the routine use of simultaneous dual-isotope myocardial scintigraphy in the near future. (orig.)

133

Differentiation of transiently ischemic from infarcted myocardium by serial imaging after a single dose of 201Tl  

International Nuclear Information System (INIS)

ch disappeared within 1-6 hours postexercise corresponded to areas supplied by coronary arteries with significant stenoses. Persistent defects were present in regions of old myocardial infarction. Six patients with acute myocardial infarction demonstrated 201Tl myocardial defects which showed no significant change over 6 hours. Redistribution of 201Tl into ischemic myocardium was demonstrated during transient coronary occlusion in dogs and after exercise stress in man

134

Clinical evaluation of the ipsilateral lung uptake of 201TlCl in spontaneous pneumothorax  

International Nuclear Information System (INIS)

A case of re-expansion pulmonary edema following the treatment of spontaneous pneumothorax was reported, and in 3 other cases of this disease, perfusion lung scintigraphy with sup(99m)Tc-MAA and myocardial scintigraphy with 201TlCl were performed in order to evaluate the regional pulmonary arterial perfusion and lung uptake of 201Tl. The perfusion decrease and the marked uptake of 201Tl were observed in the ipsilateral lung of 2 cases. In a previous study, we reported that diffuse bilateral lung uptake of 201Tl, which was distributed in more than 90% of the extravascular space of the lung, was observed in various cases with heart disease, diffuse interstitial pneumonia etc. Therefore, it seems that ipsilateral lung in cases with spontaneous pneumothorax may be accompanied with a subclinical increased vascular permeability and abnormal accumulation of interstitial fluid. Thus patients with spontaneous pneumothorax will be predisposed to re-expansion pulmonary edema. (author)

135

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

International Nuclear Information System (INIS)

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

136

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)

137

Differentiation of prostate cancer and benign prostatic hyperplasia. The clinical value of 201Tl SPECT. A pilot study  

International Nuclear Information System (INIS)

Thallium-201 (201Tl) is a recognized tumor-imaging agent; however, the usefulness of 201Tl in prostate cancer has not been studied. The purpose of this preliminary study was to evaluate the efficacy of 201Tl single-photon emission computed tomography (SPECT) imaging for differentiating prostate cancer from benign prostatic hyperplasia (BPH). 201Tl pelvic SPECT was performed in 10 patients (aged 64-78 years) with biopsy-proven BPH before transurethral resection of the prostate and 15 patients (aged 65-81 years) with biopsy-proven prostate cancer prior to any therapeutic modality or invasive surgical procedures for treatment of their prostate cancer. From the 15 patients with prostate cancer, 201Tl pelvic SPECT detected prostate cancer in 13 (86.7%) but not in 2 (13.3%) patients with Gleason scores of 5 (2+3). In contrast, all 10 patients with BPH (100.0%) had negative results of 201Tl pelvic SPECT. Our study showed that 201Tl pelvic SPECT scan is very helpful in distinguishing between prostate cancer and BPH. (author)

138

Clinical usefulness of thallium-201 myocardial single photon emission CT in cases of acute myocardial infarction  

International Nuclear Information System (INIS)

Clarification of the clinical usefulness of Single Photon Emission Computed Tomography (SPECT) compared to conventional planar Thallium-201 chloride myocardial scintigraphy in terms of its relationship to other clinical examinations was investigated. Patients consisted of 27 acute myocardial infarctions, 25 male and 2 female. Their average age was 61.2. For 25 patients it was their first attack of acute myocardial infarction, and 2 had suffered previous myocardial infarction. The following results were obtained: 1) In the apex, the scores were remarkably higher with SPECT than those with the planar image. However, in the anterior portion or septum, the scores were almost the same. In the inferior, lateral or posterior portions the scores were slightly higher on SPECT than those with the planar image. 2) Eleven out of 27 cases showed a high correspondence between the planar image and SPECT, but the other 16 were different in the identification of infarct sites. In 11 out of 16, SPECT was more accurate, but in another 3 out of 16, the planar image was more accurate because of overdiagnosis by SPECT. 3) The defects of apex might be overdiagnosed by SPECT. 4) SPECT scores showed a good correlation with the severity of wall motion disturbance. 5) Patients with severe broad defects on anteroseptal or anteroseptolateral identified by SPECT showed significantly lower ejection fraction than others. 6) The total SPECT score was inversely well correlated with ejection fraction. (J.P.N.)

139

201Tl uptake in lymphangiosis carcinomatosis  

International Nuclear Information System (INIS)

Diffuse and intense 201Tl uptake in the lungs due to lymphangiosis carcinomatosis in a patient with stage IV breast cancer is described. The intensity of uptake reflected the severity of the disease and the bad prognosis. The patient expired 14 days later from acute pulmonary failure. 201Tl as tumour imaging agent is most promising and should be explored more in selected clinical problems. (orig.)

140

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. 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)

 
 
 
 
141

Hemodynamic significance of diffuse lung uptake of 201Tl in heart diseases  

International Nuclear Information System (INIS)

Clinical significance of diffuse lung uptake of 201Tl was studied in 244 cases of various heart diseases. The grade of lung uptake of 201Tl was assessed by total lung uptake ratio (L/T), maximal lung uptake ratio (Max/T), lung to myocardium or mediastinum counts ratio (M/H or M/Med) and visual grade. L/T, Max/T, M/H and M/Med were directly correlated with pulmonary arterial pressure (PCW), and inversely correlated with cardiac output (CO) and cardiac index (CI). Among them, L/T was the best index to assess PCW, that was correlated with PCW (r=0.65), CO (r=-0.53) and CI (r=-0.45). The visual grade of 201Tl lung uptake was correlated with L/T, and the increased lung uptake was associated with a higher PCW and a lower CO as well as a lower CI. Diffuse increased lung uptake of 201Tl was observed in 29 of 41 cases (70.7%) with myocardial infarction, 25 of 29 cases (86.2%) with mitral valvular diseases and 9 of 10 cases (90.0%) with combined valvular diseases, in addition, in most cases with left heart failure and cases of NYHA 3 and 4, but that was not rarely observed in cases of NYHA 2 and without left heart failure. In heart diseases, 201Tl myocardial scintigraphy seems to be valuable for detection of left heart failure including pulmonary congestion and interstitial pulmonary edema. Total lung uptake ratio (L/T) may be useful for estimation of PCW, and the visual grade of 201Tl lung uptake may be applicable as routine index for grading of lung uptake of 201Tl. (author)

142

Determination of impurities in 201TlCl injected and 203PbCl aqueous solution by ICP-AES  

International Nuclear Information System (INIS)

201TlCl is a useful radiopharmaceutical. It is widely used to diagnose myocardial disease. An inductively coupled plasma (ICP) emission spectrometrical method for determining impurities in 201TlCl injection and 203PbCl solution is described. 201Tl in physiological saline and 203Pb in aqueous solution were checked for Al, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, Tl and Zn with a sensitivities of 0.001 ?g/ml to 0.010 ?g/ml and relative standard deviations < 10%

143

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

International Nuclear Information System (INIS)

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

144

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  

International Nuclear Information System (INIS)

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). 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)

145

Myocardial stunning in hypertrophic cardiomyopathy: recovery predicted by single photon emission computed tomographic thallium-201 scintigraphy  

International Nuclear Information System (INIS)

A young woman with hypertrophic cardiomyopathy confirmed by echocardiography and cardiac catheterization presented with chest pain and features of a large left ventricular aneurysm. The initial diagnosis was myocardial ischemia with either an evolving or an ancient myocardial infarction. Subsequently, verapamil therapy was associated with complete resolution of the extensive left ventricular wall motion abnormalities, normalization of left ventricular ejection fraction and a minimal myocardial infarction. Normal thallium uptake on single photon emission computed tomographic scintigraphy early in the hospital course predicted myocardial viability in the region of the aneurysm. Thus, orally administered verapamil may reverse spontaneous extensive myocardial ischemia in hypertrophic cardiomyopathy and possibly limit the extent of myocardial infarction in such circumstances

146

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

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The pathomorphologic mechanism responsible for abnormal perfusion imaging during thallium-201 myocardial single photon emission computed tomography ({sup 201}Tl-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 {sup 201}Tl-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 {sup 201}Tl-SPECT were compatible with the histopathology. The presence of the redistribution phenomenon may indicate ongoing fibrosis. Initial and delayed resting {sup 201}Tl-SPECT images can predict the site and progress of myocardial degeneration in patients with DMD. (author)

Nishimura, Toru; Yanagisawa, Atsuo; Sakata, Konomi; Shimoyama, Katsuya; Yoshino, Hideaki; Ishikawa, Kyozo [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine; Sakata, Hitomi; Ishihara, Tadayuki

2001-02-01

147

Experimental and clinical examinations concerning myocardial sequential scintiscanning under external work load using Tl-201. Experimentelle und klinische Untersuchung zur /sup 201/Tl Sequenz-Szintigraphie des Arbeitsmyokards  

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A total of 24 patients were subjected to myocardial sequential scintiscanning using Tl-201. For this purpose, the radio-pharmaceutical was in each case injected and a preliminary scintiscan obtained, while the patient was still at rest. Subsequently, an exercise test was carried out using the ergometer and the related changes in the density pattern were assessed by means of sequential scintiscanning. The quantitative evaluation of the scintiscans was based on the 'region of interest' technique. It could be concluded from relevant phantom studies that impulse rate differences of 4% were required to establish a diagnosis. Reliable results to differentiate coronary stenosis from myocardial infarction were obtained from an analysis of the following parameters: (a) Height of relative Tl-201 fixation over the myocardial region showing the lowest concentration; (b) difference between the relative Tl-201 fixation over the area of maximum concentration and that of minimum concentration, expressed as a percentage; changes with time in the impulse density over the region of minimum concentration following exercise on the ergometer. No more than two of these parameters were required to establish a firm diagnosis; in cases where combined analysis of all three parameters pointed to the presence of myocardial scars or reversible ischemia, this was seen to be in agreement with the findings revealed by invasive methods of examination. The load-dependent mean level of activity in the total myocardium, the discrepancy between the area of minimum activity, the background and the mean myocardial activity as well as the behaviour of the absolute impulse rate were among further criteria taken into account to confirm a certain diagnosis. Radiopharmaceutical ventricular function studies are a very useful tool for the medical surveillance of patients showing angina pectoris or myocardial infarction.

Neumayr, K.M.A.

1983-03-16

148

Simultaneous 99mTc/201Tl dual-isotope SPET with Monte Carlo-based down-scatter correction  

International Nuclear Information System (INIS)

In simultaneous technetium-99m/thallium-201 dual-isotope (DI) single-photon emission tomography (SPET), down-scatter of 99mTc photons contaminates the 201Tl image, which leads to a decrease in lesion contrast and loss of quantitative accuracy. Correction for down-scatter can be achieved by first reconstructing the 99mTc activity distribution. Subsequently, the 99mTc down-scatter in the 201Tl photopeak window is simulated and used for correction during iterative reconstruction of the 201Tl image. In this work, the down-scatter projections are calculated using a dedicated Monte Carlo simulator which is able to efficiently model the detection of lead X-rays from the collimator. An anthropomorphic torso phantom with a cardiac insert with and without cold lesions was used for evaluation of the proposed method. Excellent agreement in lesion contrast and quantitative accuracy was found between the down-scatter corrected DI-SPET 201Tl image and the virgin (i.e. separately acquired) 201Tl image, in particular when the effects of lead X-rays were included. Compensation for the noise added by down-scatter to the 201Tl image can be achieved by using a 15% lower dose of 99mTc, a 15% increase in scan time and a 12% increase in 201Tl dose. In conclusion, the Monte Carlo-based down-scatter correction recovers lesion contrast and quantitative accuracy in DI-SPET 201Tl images almost perfectly. In addition, degradations due to the added noise of down-scatter in simultaneous DI-SPET can be prevented by slight adaptations to the data acquisition protocol. (orig.)

149

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

International Nuclear Information System (INIS)

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)

150

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 {sup 201}Tl 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 {sup 201}Tl 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 {sup 201}Tl 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 {sup 201}Tl SPECT is useful for evaluating myocardial ischemia even in the elderly, but exercise electrocardiography has limitations such as lower specificity in the elderly than {sup 201}Tl SPECT. (author)

Kurata, Chinori; Uehara, Akihiko; Sugi, Toshihiko; Yamazaki, Keisuke [Hamamatsu Univ. School of Medicine, Shizuoka (Japan); Tawarahara, Kei; Mikami, Tadashi; Matoh, Fumitaka; Odagiri, Keiichi

2000-06-01

151

201Tl scintiscanning of the myocardium following radiotherapy of the thoracic region  

International Nuclear Information System (INIS)

40 patients were examined by 201Tl scintiscanning after radiotherapy of the thoracic region in breast cancer and metastasizing testicular tumors, resp. The results allowed to evaluate the clinical and electrocardiographic findings in 105 follow-up patients. From 40 patients with the greater part having no cardiac symptoms, 22 revealed irreversible 201Tl fixation disturbances and 10 storage deficiency under stress with repletion after rest. These findings are interpreted as myocardial fibrosis or ischemic reaction due to radiotherapy and conclusions for follow-up checks are recommended

152

Examinations of ischemic heart diseases by sup(201)Tl perfusion under stress  

International Nuclear Information System (INIS)

Scintigraphic examinations of the myocardial perfusion was carried out by means of sup(201)Tl perfusion. The results obtained in 23 cases are correlated with data of coronarography carried out subsequently. The sensitivity of the new non-invasive technique was found to be 77%, its specificity 90%. (L.E.)

153

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

International Nuclear Information System (INIS)

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 ?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. (author)

154

Discrete subaortic stenosis (DSS): New diagnostic and pathogenic parameters gained by gated 201Tl myocardial scintigraphy (TMS) and multigated acquisition blood-pool ventriculography (MUGA)  

International Nuclear Information System (INIS)

Nineteen patients suffering from DSS, diagnosed by echocardiography, heart catheterization and angiography were further evaluated by radionuclide studies including ECG-gated 201TI-myocardial scintigraphy (TMS) and multigated (MUGA) acquisition blood pool ventriculography. The results of these patients were further compared with results obtained in an earlier study of 20 patients suffering from Idiopathic Hypertrophic Subaortic Stenosis (IHSS), and with a group of 28 disease-free patients all of whom were studied by the same methods. All four parameters characteristic of IHSS were demonstrated in 100% of the patients with DSS as well. The close similarity of DSS and IHSS as introduced by the results of this study, serves as an additional proof supporting our previously expressed hypothesis that most of the cases of DSS involve dynamic features similar to those obstructive cardiomyopathy. Accordingly, TMS and MUGA studies seem to provide an additional sensitive tool for the early diagnosis and evaluation of DSS patients, in a similar manner to that of IHSS patients. The value of this method for the postsurgical follow-up of DSS patients is currently investigated. (orig.)

155

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

International Nuclear Information System (INIS)

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. 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.)

156

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

International Nuclear Information System (INIS)

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 imaging. Prone imaging may only be helpful where the inferior defect is of moderate severity but no LL defect is seen

157

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

International Nuclear Information System (INIS)

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 a 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.)

158

Measurement of myocardial infarction fraction using single photon emission computed tomography  

International Nuclear Information System (INIS)

Although infarct size correlates generally with prognosis after acute myocardial infarction, an absolute measure of infarct size may have differing prognostic significance depending on absolute left ventricular mass. To test the hypothesis that single photon emission computed tomography can accurately measure myocardial infarct size as a percent of total left ventricular mass (''infarction fraction''), thallium-201 and technetium-99m pyrophosphate tomograms were acquired in 21 dogs 24 to 48 hours after fixed occlusion of the left anterior descending or circumflex coronary artery. Pathologic infarct weight was measured as the myocardial mass that showed no staining with triphenyltetrazolium chloride. Scintigraphic infarct mass by technetium-99m pyrophosphate was calculated from the total number of left ventricular volume elements (voxels) demonstrating technetium-99m pyrophosphate uptake X voxel dimension [( 0.476 cm]3) X specific gravity of myocardium (1.05 g/cm3). Scintigraphic left ventricular mass was calculated in a similar fashion using an overlay of the thallium-201 and technetium-99m pyrophosphate scans. The ''infarction fraction'' was calculated as: infarction fraction = infarct mass/left ventricular mass. There was good correlation between single photon emission computed tomography and pathologic measurements of infarct mass, left ventricular mass, and ''infarction fraction''

159

Assessment of left ventricular function by electrocardiogram-gated myocardial single photon emission computed tomography using quantitative gated single photon emission computed tomography software  

International Nuclear Information System (INIS)

Electrocardiogram (ECG)-gated myocardial single photon emission computed tomography (SPECT) can assess left ventricular (LV) perfusion and function easily using quantitative gated SPECT (QGS) software. ECG-gated SPECT was performed in 44 patients with coronary artery disease under post-stress and resting conditions to assess the values of LV functional parameters, by comparison to LV ejection fraction derived from gated blood pool scan and myocardial characteristics. A good correlation was obtained between ejection fraction using QGS and that using cardiac blood pool scan (r=0.812). Some patients with myocardial ischemia had lower ejection fraction under post-stress compared to resting conditions, indicating post-stress LV dysfunction. LV wall motion and wall thickening were significantly impaired in ischemic and infarcted myocardium, and the degree of abnormality in the infarcted areas was greater than in the ischemia area. LV functional parameters derived using QGS were useful to assess post-stress LV dysfunction and myocardial viability. In conclusion, ECG-gated myocardial SPECT permits simultaneous quantitative assessment of myocardial perfusion and function. (author)

160

Clinical usefulness of {sup 11}C-MET PET and {sup 201}Tl SPECT for differentiation of recurrent glioma from radiation necrosis  

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The clinical usefulness of L-methyl-{sup 11}C-methionine positron emission tomography ({sup 11}C-MET PET) and thallium-201 single photon emission computed tomography ({sup 201}Tl SPECT) for distinguishing glioma recurrence from radiation-induced changes was evaluated. Ten patients with lesions highly suggestive of recurrent glioma on magnetic resonance imaging underwent {sup 11}C-MET PET and {sup 201}Tl SPECT studies. Two patients were examined twice, so a total of 12 studies were performed. The clinical diagnoses were five recurrent gliomas and seven radiation necrosis. The five recurrent gliomas appeared as increased uptakes on both {sup 11}C-MET PET and {sup 201}Tl SPECT scans. Four of the seven radiation necrosis lesions also appeared as increased uptakes on the {sup 201}Tl SPECT scans. In contrast, only one radiation necrosis appeared as increased uptake on the {sup 11}C-MET PET scans. There was no significant difference in {sup 201}Tl SPECT indices between radiation necrosis and tumor recurrence, but the ratio of the differential absorption ratio of tumor tissue to that of the homologous contralateral gray matter in PET of recurrent glioma was significantly higher than that of radiation necrosis. {sup 11}C-MET PET is superior to {sup 201}Tl SPECT for the differentiation of tumor recurrence from radiation necrosis and delineation of the extent of the tumor. (author)

Sonoda, Yukihiko; Kumabe, Toshihiro; Takahashi, Toshiei; Shirane, Reizo; Yoshimoto, Takashi [Tohoku Univ., Sendai (Japan). School of Medicine

1998-06-01

 
 
 
 
161

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 well as exercise-induced ischaemia. (orig.)

162

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

Science.gov (United States)

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 lump-shaped 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 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. PMID:3496629

Ogawa, K; Kunieda, E; Kubo, A; Hashimoto, S

1987-03-01

163

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)

164

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.)

165

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

166

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

167

How reliable is myocardial imaging in the diagnosis of acute myocardial infarction  

International Nuclear Information System (INIS)

Myocardial scintigraphic techniques available presently allow a sensitive and relatively specific diagnosis of acute myocardial infarction when they are used correctly, although every technique has definite limitations. Small myocardial infarcts (less than 3 gm.) may be missed, and there are temporal limitations in the usefulness of the scintigraphic techniques. The development of tomographic methodology that may be used with single-photon radionuclide emitters (including technetium and 201Tl will allow the detection of relatively small abnormalities in myocardial perfusion and regions of myocardial infarction and will help to provide a more objective interpretation of the myocardial scintigrams. The use of overlay techniques allowing simultaneous assessment of myocardial perfusion, infarct-avid imaging, and radionuclide ventriculograms will provide insight into the relevant aspects of the extent of myocardial damage, the relationship of damage to myocardial perfusion, and the functional impact of myocardial infarction on ventricular performance

168

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

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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.)

169

/sup 201/Tl uptake in lymphangiosis carcinomatosis. Case report  

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Diffuse and intense /sup 201/Tl uptake in the lungs due to lymphangiosis carcinomatosis in a patient with stage IV breast cancer is described. The intensity of uptake reflected the severity of the disease and the bad prognosis. The patient expired 14 days later from acute pulmonary failure. /sup 201/Tl as tumour imaging agent is most promising and should be explored more in selected clinical problems.

Elgazzar, A.H.; Abdel-Dayem, H. M.; Sahweel, A.; Zaki, O.; Mahmoud, A.; Omar, Y.T.

1988-02-01

170

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

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

171

Leg 201Tl-SPECT in chronic exertional compartment syndrome  

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

172

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. 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.)

173

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 correction were artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 ± 0.03 g/ml in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer 133Xe. Because of the low energy of 133Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one of the systems provided correct emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study

174

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

175

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

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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)

176

Evaluation of simultaneous 201Tl/99mTc dual-isotope cardiac SPECT imaging with model-based crosstalk compensation using canine studies  

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Background Simultaneous 201Tl/99mTc-Sestamibi dual-isotope myocardial perfusion SPECT imaging can reduce imaging time and produce perfectly registered rest/stress images. However, crosstalk from 99mTc into 201Tl images can significantly reduce 201Tl image quality. We have developed a model-based compensation (MBC) method to compensate for this crosstalk. The method has previously been validated with phantom and simulation studies. In this study, we evaluated the MBC method using a canine model. Methods Left anterior descending or left circumflex coronary artery stenoses were created in 50 adult mongrel dogs weighing 20–30 kg. The dogs were injected with 111 MBq (3 mCi) of 201Tl at rest, and a SPECT study acquired. Stress was induced by administering adenosine to the dog, followed by injection of 740 MBq (20 mCi) of 99mTc-Sestamibi at peak stress. A second SPECT study was performed with data acquired in both 201Tl and 99mTc energy windows to provide simultaneous dual-isotope projection data. The images were reconstructed using the ordered subsets-expectation maximization (OS-EM) reconstruction algorithm with compensation for attenuation, scatter and detector response. For simultaneously acquired 201Tl data, we also applied the MBC method to compensate for crosstalk contamination from 99mTc. Results Without compensation, 99mTc crosstalk increased the estimated 201Tl activity concentration in the rest images and reduced defect contrast. After MBC, the 201Tl images were in good agreement with the registered single isotope images and ex vivo count data. The ischemic (IS) to non-ischemic (NIS) region 201Tl activity concentration ratios were computed for single isotope and dual isotope studies. The correlation with ex vivo IS-NIS ratios was 0.815 after MBC, compared to the 0.495 from data without compensation. In addition, the regression line for the IS-NIS ratios with MBC was almost parallel to the line of identity with a slope of 0.93, compared to a slope of 0.45 without compensation. Conclusions These results demonstrate that model-based crosstalk compensation can provide substantial reduction of crosstalk effects in simultaneously acquired myocardial perfusion SPECT images in living biological systems. PMID:24366822

Du, Y.; Links, J. M.; Becker, L.; DiPaula, A. F.; Frank, T.; Schuleri, K. H.; Lardo, A. C.; Frey, E. C.

2014-01-01

177

Usefulness of lung and right ventricular thallium-201 uptake during single photon emission computed tomography in exercise testing of patients with coronary artery disease  

International Nuclear Information System (INIS)

Increased pulmonary or right ventricular 201Tl uptake during the exercise test has been used as a marker of multivessel coronary artery disease. The most useful method for assessing the severity of coronary artery disease was evaluated among conventional evaluation of single photon emission computed tomography (SPECT), measurement of lung to heart uptake ratio (L/H), and right ventricular to left ventricular uptake ratio (RV/LV) on 201Tl images during exercise testing. Regions-of-interest (4 x 4 pixels) were placed at the lung and the heart, and L/H was defined as mean lung uptake/mean heart uptake. Correspondingly, regions-of-interest (4 x 4 pixels) were placed at the RV and the LV, and RV/LV was defined as maximum RV uptake/maximum LV uptake. L/H and RV/LV on the initial image were analyzed in 216 patients (angiographically normal coronary arteries: 89, single-vessel disease: 82, multivessel disease: 45). The diagnostic value was evaluated using the receiver operating characteristic curve. All methods showed significantly higher values in patients with multivessel disease than in patients with no coronary artery disease or single-vessel disease. L/H was significantly higher in patients with prior myocardial infarction and RV/LV was significantly higher in patients without infarction. The sensitivity of only conventional SPECT evaluation for multivessel coronary artery disease was low (sensitivity 53%, specificity 94%). However, addition of evalpecificity 94%). However, addition of evaluation of L/H and RV/LV to SPECT improved the sensitivity for multivessel coronary artery disease (sensitivity 93%, specificity 49%). The diagnostic sensitivity for multivessel coronary artery disease was improved by adding L/H and RV/LV to conventional evaluation of exercise 201Tl SPECT. L/H and RV/LV during exercise 201Tl imaging may provide additional information regarding the severity of coronary artery disease. (author)

178

Venous uptake of /sup 201/Tl as thallous chloride  

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Thallium-201, injected as thallous chloride, has been found to adhere to or be taken up by the vein into which it is injected, permitting images to be obtained of human veins up to 4 h following injection. A digoxin-insensitive rat vein model also retained /sup 201/Tl but for shorter periods of time. /sup 201/Tl uptake is independent of the solution into which it is introduced, whether 5% dextrose or 0.9% sodium chloride. This technique permits multiple delayed views of normal veins to be obtained but is of uncertain value in the evaluation of thrombophlebitis of the calf because of rather poor resolution and high cost.

Silberstein, E.B.; Thomas, S.R. (Cincinnati Univ., OH (USA). Coll. of Medicine); Robbins, P.J.; Fortman, D.L. (Office of Science and Technology, Cincinnati, OH (USA). Food and Drug Administration, Nuclear Medicine Lab.); Sill, P.

1984-05-01

179

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

180

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

 
 
 
 
181

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

International Nuclear Information System (INIS)

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

182

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

183

Advanced quantitative 201-Tl gated SPECT (QGS-A) images for the assessment of left ventricular function and volumes. Comparison with two-dimensional echocardiography  

International Nuclear Information System (INIS)

The aim of this study was to assess the clinical significance and validity of the advanced quantitative 201-Tl and 99m-Tc gated SPECT (QGS-A) methods. We studied 79 patients (48 men, 31 women; mean age 70±14 yr) with cardiomyopathy (n=4) and ischemic (n=57) or congestive heart disease (n=18). All subjects were investigated as to the correlation between values with QGS-A and UCG. Either 201-Tl (n=51) or 99m-Tc (n=28) gated SPECT was performed at rest (n=48) or stress (n=31) stage followed by UCG within one month. Gated SPECT data, including EDV, ESV, and LVEF, were quantified by using an automatic algorithm as QGS-A, whereas UCG data (EDV, ESV, and LVEF) were determined by the standard technique. A significant correlation was found between 201-Tl or 99m-Tc QGS-A and UCG with respect to EDV, ESV, and LVEF (201-Tl: r=0.761, 0.882, 0.819; 99m-Tc: r=0.515, 0.765, 0.695, respectively, all p values <0.01), regardless of the use of rest images. The mean values of EDV, ESV, and LVEF calculated by QGS-A were significantly lower than those of UCG (all p values <0.01). LV volumes and LVEF calculated by both 201-Tl and 99m-Tc QGS-A were significantly correlated with those obtained by UCG. These findings support the clinical significance and validity of 201-Tl and 99m-Tc QGS-A for simultaneously assessing both LV function and myocardial perfusion imaging. (author)

184

Comparison of 99mTc-tetrofosmin with 201Tl imaging in the detection of CAD  

International Nuclear Information System (INIS)

Full text: This prospective study was planned to compare the results of technetium-99m tetrofosmin with thallium-201 imaging in the detection of coronary artery disease (CAD). A total of 25 male patients (mean age : 49.32 y) underwent technetium-99m-tetrofosmin and thallium-201 planar imaging on different days. Each study was divided into 15 segments for analysis. Semiquantitative visual analysis was performed by assigning regional tracer activities in each segment on 4 points scoring system ranging from 0 to 3 with 0 representing normal uptake, 1 - mild, 2 - moderate, 3 - severe reduction in activity. Of the 375 myocardial segments, 355 (94.7%) segments were concordant, of which 276 (77.7%) were normal, 46 (13%) were fixed defects segments and 33 (9.3%) were reversible defects segments. The remaining 20 (5.3) segments were discordant. 99mTc-tetrofosmin shows comparable results with 201Tl in both normal and in patients with non-reversible perfusion defects. This study also shows that 99mTc-tetrofosmin gives better quality images than 201Tl

185

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

186

Physiological basis for stress-induced myocardial stunning as assessed by gated single-photon emission computed tomography  

International Nuclear Information System (INIS)

Postischemic myocardial stunning as assessed by gated single-photon emission computed tomography (SPECT) has been criticized for being a perfusion-associated artifact caused by false endocardial tracking. We hypothesized that if severe perfusion defects all cause false wall motion abnormality, they should be observed regardless of the underlying mechanisms of perfusion abnormality. We evaluated 132 patients with stress-induced perfusion defects of moderate severity or more after exercise (n=84) or adenosine triphosphate disodium (ATP) stress (n=48) were evaluated using gated 99mTc-sestamibi SPECT. Summed stress and difference scores were similar in the 2 groups. However, the overall incidence of post-stress stunning was 54% in the exercise group, but only 19% in the ATP group (p<0.0001). Furthermore, based on the severity of coronary artery stenosis in 43 patients with 1-vessel disease, the prevalence of post-stress stunning was 77% in patients with ?99% coronary stenosis, 67% in those with 90% stenosis, and 29% in those with 75% stenosis after exercise stress, whereas it was 57% in those with ?99% stenosis, 17% in those with 90% stenosis, and 0% in those with 75% stenosis after ATP stress (p=0.003). The predominant mechanism of post-stress wall motion abnormality observed by gated SPECT was thought to be severe myocardial ischemia, but not a perfusion-associated artifact. Thus, this scintigraphic finding was regarded as actual myocardial stunning. (author)

187

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 myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events. (orig.)

188

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

Energy Technology Data Exchange (ETDEWEB)

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 {sup 99m}Tc-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 {sup 99m}Tc-sestamibi SPET, and showed normal epicardial vessels in all the cases. These results indicate that {sup 99m}Tc-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 {sup 99m}Tc-sestamibi SPET can be a useful non-invasive method to identify subclinical myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events. (orig.) With 2 figs., 2 tabs., 21 refs.

Schillaci, O. [Nuclear Medicine, University of l`Aquila (Italy); Lagana, B.; Gentile, R.; Tubani, L.; Baratta, L. [Department of Clinical Medicine, University ``La Sapienza``, Rome (Italy); Danieli, R.; Scopinaro, F. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy)

1999-07-01

189

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

International Nuclear Information System (INIS)

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

190

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)

191

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-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)

192

Quantification of the extent of myocardial infarction by thallium-201 single photon emission computed tomography  

International Nuclear Information System (INIS)

The diagnostic capability of a circumferential profile analysis with a two-dimensional representation of Tl-201 myocardial SPECT depends on the normal range of thallium distribution. The present study was thus to determine the lower normal limits useful for assessing the precise extent of myocardial infarction (MI). The quantitative analysis of Tl-201 myocardial SPECT was correlated with pathological findings of the heart in 50 autopsy cases (28 with MI; 22 without MI). The lower normal limits were 2.5 standard deviations below the mean values calculated using profiles normalized to the maximum pixel count observed in each profile. Using this lower normal limit, the sensitivity was 63.8%; specificity was 87.4%; and accuracy was 80.7% for determining the extent of ischemic lesions. However, for detecting MI, the sensitivity by quantitative analysis was 97%, which was higher than that by visual analysis. Non-transmural infarction 2.5 cm in size, undetectable by visual analysis, was detected by two-dimensional polar representation. However, the specificity of detecting MI was low (59%). The detectability of MI extent varied from site to site; false negative lesions were frequent in the septal region, and false positive lesions in the posterolateral region of the dilated hypertrophic heart. In conclusion, Tl-201 myocardial SPECT is useful for evaluating MI automatically, although possible false positive diagnosis must be taken into accounts in cases of dilated hypertrophio accounts in cases of dilated hypertrophic heart. (N.K.)

193

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

Energy Technology Data Exchange (ETDEWEB)

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 or with CFCs. Because of the greater sensitivity, however, a much shorter acquisition time is required with CFCs. (orig.) With 5 figs., 2 tabs., 5 refs.

Everaert, H.; Vanhove, C.; Franken, P.R. [Division of Nuclear Medicine, University Hospital, Free University of Brussels (AZ VUB), Brussels (Belgium); Hamill, J.J. [Nuclear Medicine Group, Siemens Medical Systems Inc., Hoffman Estates, Ill. (United States)

1998-01-01

194

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

International Nuclear Information System (INIS)

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

195

[Effect of scatter correction on quantification of myocardial SPECT and application to dual-energy acquisition using triple-energy window method].  

Science.gov (United States)

Triple-energy window (TEW) method is a simple and practical approach for correcting Compton scatter in single-photon emission tracer studies. The fraction of scatter correction, with a point source or 30 ml-syringe placed under the camera, was measured by the TEW method. The scatter fraction was 55% for 201Tl, 29% for 99mTc, 57% for 123I. Composite energy spectra were generated and separated by the TEW method. Combination of 99mTc and 201Tl was separated well, and 201Tl and 123I were separated within an error of 10%; whereas asymmetric photopeak energy window was necessary for separating 123I and 99mTc. By applying this method to myocardial SPECT study, the effect of scatter elimination was investigated in each myocardial wall by polar may and profile curve analysis. The effect of scatter was higher in the septum and the inferior wall. The count ratio relative to the anterior wall including scatter was 9% higher in 123I, 7-8% higher in 99mTc and 6% higher in 201Tl. Apparent count loss after scatter correction was 30% for 123I, 13% for 99mTc and 38% for 201Tl. Image contrast, as defined myocardium-to-left ventricular cavity count ratio, improved by scatter correction. Since the influence of Compton scatter was significant in cardiac planar and SPECT studies; the degree of scatter fraction should be kept in mind both in quantification and visual interpretation. PMID:8523844

Nakajima, K; Matsudaira, M; Yamada, M; Taki, J; Tonami, N; Hisada, K

1995-09-01

196

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 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.)

197

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

Science.gov (United States)

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 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. PMID:7607269

Knapp, F F; Kropp, J

1995-04-01

198

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

International Nuclear Information System (INIS)

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

199

Two cases of primary hyperparathyroidism successfully detected by preoperative 201Tl-chloride scintigraphy  

International Nuclear Information System (INIS)

Both cases showed a solitary adenoma weighing 1.1 and 1.0 g, respectively. It was useful to compare 201Tl-chloride and sup(99m)Tc-pertechnetate scintigrams to eliminate the image of the thyroid visualized by 201Tl-chloride. 201Tl-chloride allows visualization of parathyroid adenomas weighing about 1 g, and the use of subtraction is expected to improve further the accuracy of the modality. (Chiba, N.)

200

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

Energy Technology Data Exchange (ETDEWEB)

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)

Lin, Jen-Jhy; Hsu, Hsiu-Bao; Sun, Shung-Shung; Kao, Chia-Hung [China Medical Coll., Taichung, Taiwan (China). Hospital; Wang, Jhi-Joung [Chi-Mei Medical Center, Tainan, Taiwan (China); Ho, Shung-Tai [National Defense Medical Center, Taipei, Taiwan (China). School of Medicine

2003-01-01

 
 
 
 
201

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)

202

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

International Nuclear Information System (INIS)

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

203

Impact of Co-morbidity on the Risk of First-Time Myocardial Infarction, Stroke, or Death After Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging  

DEFF Research Database (Denmark)

The impact of co-morbidity on the cardiovascular risk after single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) remains unclear. We examined the association between a normal versus abnormal SPECT MPI scan on 10-year risk of myocardial infarction, stroke, and all-cause death, overall and according to co-morbidity level. We identified all patients without previous myocardial infarction or cerebrovascular disease, who had an SPECT MPI performed at Aarhus University Hospital Skejby during 1999 to 2011. We categorized the SPECT MPI scan as normal (no defects) or abnormal (reversible and/or fixed defects). Using nationwide medical registries, we obtained information on co-morbidity level (using Charlson co-morbidity index) and outcomes. We used Cox regression to compute hazard ratios with 95% confidence intervals (CIs), adjusting for gender, age, and co-morbidity level. Among 7,040 patients, 4,962 (70%) had normal scans and 2,078 (30%) abnormal scans. Patients with a normal versus abnormal scan had a 10-year risk of 5.7% versus 10.9% for myocardial infarction, 6.0% versus 7.8% for stroke, and 16.5% versus 29.0% for all-cause death. After adjustment, an abnormal scan was associated with increased risk of myocardial infarction (adjusted hazard ratio 1.73, 95% CI 1.37 to 2.18) and all-cause death (1.42, 95% CI 1.23 to 1.65) but not stroke (1.12, 95% CI 0.86 to 1.45). Co-morbidity level did not affect substantially the association between the scan result and the outcomes. In conclusion, independently of co-morbidity level, an abnormal SPECT MPI scan was associated with an increased 10-year risk of myocardial infarction and all-cause death but not stroke.

Schelde, Astrid Blicher; Schmidt, Morten

2014-01-01

204

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

International Nuclear Information System (INIS)

y released from DTPA in serum. Apart from some urinary excretion, the biodistribution of DOTA-chelated 201Tl3+ was similar to that of free (ionic) 201Tl+ and did not match the biodistribution of 177Lu(III)-DOTA. This indicated a limited stability of 201Tl(III)-DOTA complexes in vivo. Conclusion: Despite promising results on the labeling and in vitro stability of 201Tl(III)-DOTA, our in vivo results indicate that the integrity of 201Tl(III)-DOTA decreases to 201Tl3+ as a radiolabel for tracer imaging.

205

Diagnosis of left ventricular aneurysm by exercise thallium-201 myocardial single photon emission computed tomography  

International Nuclear Information System (INIS)

Seventy nine patients with acute myocardial infarction underwent exercise thallium-201 myocardial SPECT combined with selective coronary angiography and left ventriculography to determine post-infarction left ventricular (LV) aneurysm. Ventricular wall morphology on either horizontal or vertical long-axis images was visually classified as convergent (C), parallel (P), or divergent (D) wall. According to morphological types from poststress to delayed images, the patients were also divided into five groups: Group A (n=36) having C-C, Group B (n=8) having P-C, Group C (n=7) having P-P, Group D (n=5) having D-P, and Group E (n=23) having D-D. The highest incidence of LV aneurysm was seen in Group E (21/23), followed by Group D (3/5), and Group C (3/7). When patients in Groups D or E, all of whom had anterior infarction, were defined as positive for LV aneurysm, the diagnostic sensitivity, specificity, and accuracy of SPECT were 89%, 92%, and 86%, respectively. Two of three patients with false negative diagnosis had only apical involvement. Groups D and E had significantly larger defect scores, as calculated by polar maps, than the other three groups. When patients with anterior infarction with defect scores of 200 or greater were defined positive, the sensitivity, specificity, and accuracy of SPECT in determining LV aneurysm were 96%, 75%, and 86%, respectively. One false negative case was apical infarction, and one of the two false positive cases was extensive anteroseptse positive cases was extensive anteroseptal infarction involving the apex. These results suggest that LV aneurysm could be diagnosed only by exercise SPECT, and that it could be characterized by extensive and severe aplicoanterior infarction and a divergent-type ventricular wall arrangement on a poststress SPECT images. (N.K.)

206

Alterations in myocardial thallium-201 distribution in patients with chronic systemic hypertension undergoing single-photon emission computed tomography  

Energy Technology Data Exchange (ETDEWEB)

To characterize thallium-201 distribution in single-photon emission computed tomography (SPECT) cardiac images and polar bullseye maps, 100 patients with chronic systemic hypertension due to end-stage renal disease were studied and the results compared with those in 35 normotensive control subjects. Thallium-201 SPECT was performed after exercise in all control subjects and 70 hypertensive patients, and after intravenous dipyridamole in 30 patients. A frequent finding in hypertensive patients was a fixed decrease in the normal lateral-to-septal count density ratio in immediate thallium-201 SPECT images (1.02 +/- 0.10 vs 1.17 +/- 0.08 in control subjects, p less than 0.00001) and in 3-hour delayed images (1.02 +/- 0.11 vs 1.11 +/- 0.08 in control subjects, p less than 0.00001). No significant difference in count density ratio was present in patients undergoing treadmill versus diypridamole intervention. In 35 patients the count density ratio was greater than 2.0 standard deviations below the normal mean, creating the false impression of a fixed lateral defect (i.e., myocardial infarction). In 12 patients, myocardial wall thickness was measured at end-diastole by 2-dimensional echocardiography. Wall thickness was increased (greater than 11 mm) in all patients. The mean lateral-to-septal wall thickness ratio was 1.08 +/- 1.11; in no patient was the ratio less than 0.76 to indicate selective septal hypertrophy. The lateral-to-septal wall thickness and lateral-to-septal thallium-201 count density ratios correlated poorly (r = 0.43).

DePuey, E.G.; Guertler-Krawczynska, E.; Perkins, J.V.; Robbins, W.L.; Whelchel, J.D.; Clements, S.D.

1988-08-01

207

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

208

Alterations in myocardial thallium-201 distribution in patients with chronic systemic hypertension undergoing single-photon emission computed tomography  

International Nuclear Information System (INIS)

To characterize thallium-201 distribution in single-photon emission computed tomography (SPECT) cardiac images and polar bullseye maps, 100 patients with chronic systemic hypertension due to end-stage renal disease were studied and the results compared with those in 35 normotensive control subjects. Thallium-201 SPECT was performed after exercise in all control subjects and 70 hypertensive patients, and after intravenous dipyridamole in 30 patients. A frequent finding in hypertensive patients was a fixed decrease in the normal lateral-to-septal count density ratio in immediate thallium-201 SPECT images (1.02 +/- 0.10 vs 1.17 +/- 0.08 in control subjects, p less than 0.00001) and in 3-hour delayed images (1.02 +/- 0.11 vs 1.11 +/- 0.08 in control subjects, p less than 0.00001). No significant difference in count density ratio was present in patients undergoing treadmill versus diypridamole intervention. In 35 patients the count density ratio was greater than 2.0 standard deviations below the normal mean, creating the false impression of a fixed lateral defect (i.e., myocardial infarction). In 12 patients, myocardial wall thickness was measured at end-diastole by 2-dimensional echocardiography. Wall thickness was increased (greater than 11 mm) in all patients. The mean lateral-to-septal wall thickness ratio was 1.08 +/- 1.11; in no patient was the ratio less than 0.76 to indicate selective septal hypertrophy. The lateral-to-septal wall thickness and lateral-to-septal thal wall thickness and lateral-to-septal thallium-201 count density ratios correlated poorly (r = 0.43)

209

ECG-gated single photon emission computed tomography for thallium-201 myocardial imaging in patients with hypertrophic cardiomyopathy  

International Nuclear Information System (INIS)

The purpose of this study is to evaluate the clinical usefulness of ECG-gated single photon emission computed tomography for Tl-201 myocardial imaging (SPECT) in the diagnosis of hypertrophic cardiomyopathies. Using a rotating dual-gamma camera system (TOSHIBA GCA-70-A-S), SPECT was performed in 23 HCM and 8 normal cases, including 12 and 2 cases with ECG-gated acquisition, respectively. After i.v. injection of 3.0 mCi of Tl-201, non-gated SPECT data were collected for 6 minutes, and thereafter gated SPECT data were collected for total sampling time of 45 to 60 minutes by MUGA method for 6-10 frames/cardiac cycle. Transaxial tomographic image was reconstructed and the oblique angle tomographic imaging along the LV long axis was also done according to Borrello's method. Location and extent of localized LV wall thickening were clearly visible, especially by gated SPECT. LV cavity form in gated SPECT image was highly coincident with that of LVG. LV wall thickness measured by oblique angle tomographic image of gated SPECT was well correlated with that by UCG. (r = 0.812, p < 0.001) In summary, despite rather long acquisition time (45 to 60 minutes), our gated SPECT method was available for clinical use to diagnose hypertrophic cardiomyopathy. (author)

210

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

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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

211

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

212

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

International Nuclear Information System (INIS)

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

213

Quantitative evaluation of intermittent claudication by 201Tl perfusion scintigraphy  

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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)

214

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

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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)

215

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

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

216

A mechanism for myocardial uptake of /sup 201/Tl  

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

217

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

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

218

New method of estimating myocardial infarct size using technetium-99m pyrophosphate and thallium-201 dual single photon emission computed tomography imaging  

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A new method was devised to estimate infarct size using dual single photon emission computed tomography with thallium-201 and technetium-99m pyrophosphate. Designating the ratio of infarct area to whole myocardial volume as %MI, the correlation of %MI with other markers of left ventricular dysfunction was examined: peak creatine kinase, ejection fraction and left ventricular asynergy. As %MI correlated well with these markers, it is considered that %MI will be useful for estimating infarct size and predicting the severity of left ventricular dysfunction in the early stage of acute myocardial infarction. (author)

Maruyama, Yoshiaki; Kato, Toru; Ito, Hiroyuki; Tanaka, Shugo; Yoshimoto, Nobuo [Saitama Medical School, Kawagoe (Japan). Saitama Medical Center; Kishi, Yukio; Numano, Fujio

1999-03-01

219

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

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

220

Effect of glucose-insulin-potassium infusion on thallium myocardial clearance  

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earance after the saline infusion. Heart rate, aortic and left atrial pressure, sonomicrometer-measured transmural myocardial wall thickness, microsphere-determined myocardial blood flow, and blood glucose and potassium concentrations did not change significantly during GIK or saline infusions. Thus, GIK infusion appears to increase net 201Tl clearance from myocardial zones with and without initial 201Tl loading

 
 
 
 
221

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

222

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

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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

223

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

224

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

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Fifty-five patients with bone lesions underwent 201Tl-chloride (201Tl) scintigraphy to evaluate its findings and usefulness for the diagnosis of bone metastases. 201Tl scintigraphy was performed 15 minutes (early scan) and 2 hour (delayed scan) after iv injection of 5.55 MBq/kg of 201Tl-chloride. To evaluate the degree of tracer retention at the lesions, we calculated retention index after setting regions of interest in each lesion demonstrated tracer uptake in both early and delayed scans. Among 118 pathologically and/or clinically comfirmed bone metastases, 201Tl planar images disclosed 90 (76.3%) and 88 (74.6%) lesions on early and delayed scans, respectively. SPECT images were preferable for the evaluation of the lesions in the spine, thoracic cage and pelvis. Correlation of tumor size with findings on 201Tl images demonstrated 90.5% sensitivity for the metastases more than 7 cm3. No correlational difference was seen in the sensitivity depending on primary cancers. The overall retention index of bone metastases was -21.4±47.1. Bone metastases of pulmonary adenocarcinomas and small cell carcinomas demonstrated higher retention index than pulmonary squamous cell carcinomas and breast cancers. On 201Tl images, no abnormal tracer uptake was seen in benign lesions detected by 99mTc-hydroxymethylene diphosphonate (99mTc-HMDP) images except 5 lesions. The 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)

225

Comparison of post-exercise and post-vasodilator stress myocardial stunning as assessed by electrocardiogram-gated single-photon emission computed tomography  

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Exercise gated single-photon emission computed tomography (SPECT) using technetium-99m (99mTc)-sestamibi evaluates both myocardial perfusion during stress and wall motion >30 min after the stress, which has the potential to assess not only exercise-induced myocardial ischemia but also the development of myocardial stunning. To evaluate the incidence of post-stress myocardial stunning, as well as comparing the effects of different stress methods on the development of stunning, 179 consecutive patients with known or suspected coronary artery disease (CAD) underwent 99mTc-sestamibi SPECT with either exercise (n=135) or adenosine triphosphate disodium (ATP) (n=44). Electrocardiogram-gated SPECT images were acquired >30 min after the stress and again 4 h later, and perfusion and wall motion were evaluated. Post-stress myocardial stunning occurred in 24 patients (13%): 22 after exercise and 2 after ATP stress. The magnitude of the transient wall motion abnormality after exercise was greater in patients with severe ischemia, compared with those with mild-to-moderate ischemia (p99mTc-sestamibi gated SPECT, myocardial stunning is frequently observed after exercise and correlates with the severity of myocardial ischemia, but this does not occur with ATP, which is regarded as a specific marker for severe CAD. (author)

226

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

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

227

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

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

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

2001-01-01

228

Gated SPECT with 201-Tl and 99m-Tc HMIBI in clinical practice - why not?  

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Myocardial scintigraphy by means of a slef-developed, simplified technique of gated SPECT (ECG-gated Single Photon Emission Computed Tomography presented. The paper is intended to illustrate method, practicability and advantages of this expanded form of diagnosis. (orig./MG)

229

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

International Nuclear Information System (INIS)

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)

230

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

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

231

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

232

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)

233

Diagnostic evaluation of 201Tl-chloride scintigraphy and ultrasonography in thyroid tumor  

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To evaluate the diagnostic value of 201Tl image and ultrasonography (USG) for thyroid carcinoma, we retrospectively investigated 34 cases of thyroidectomy. In regard to 201Tl image findings, sensitivity, specificity, accuracy rate and confirmation rates were 84 %, 56 %, 76 % and 84 %, respectively. Especially, the sensitivity rate of papillary adenocarcinoma was 94 %. In the case of USG, sensitivity, specificity, accuracy rate and confirmation rates were 60 %, 56 %, 59 % and 79 %, respectively. (author)

234

Extraction chromatography in isotope production: application in the production of 67Ga and 201Tl  

International Nuclear Information System (INIS)

Extraction chromatography was applied to the production of the radioisotopes 67Ga and 201Tl. 67Ga was produced by irradiation of natural zinc target with 24 MeV protons in a cyclotron. The separation of 67Ga was carried out by extraction chromatography from 6N HCL. 201Tl was produced in a similar way using lead as a precursor, and it was extracted using 4N HNO3 or HCL. (U.K.)

235

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  

International Nuclear Information System (INIS)

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)

236

Effect of diltiazem on myocardial infarct size estimated by enzyme release, serial thallium-201 single-photon emission computed tomography and radionuclide angiography  

International Nuclear Information System (INIS)

Diltiazem is a calcium antagonist with demonstrated experimental cardioprotective effects. Its effects on myocardial infarct size were studied in 34 patients admitted within 6 hours after the first symptoms of acute myocardial infarction. These patients were randomized, double-blind to placebo or diltiazem (10-mg intravenous bolus followed by 15 mg/hr intravenous infusion during 72 hours, followed by 4 X 60 mg during 21 days). Myocardial infarct size was assessed by plasma creatine kinase and creatine kinase-MB indexes, perfusion defect scores using single-photon emission computed tomography with thallium-201 and left ventricular ejection fraction measured by radionuclide angiography. Tomographic and angiographic scanning was performed serially before randomization, after 48 hours and 21 days later. Groups were comparable in terms of age, sex, inclusion time and baseline infarct location and size. Results showed no difference in creatine kinase and creatine kinase-MB data between controls and treated patients, a significant decrease in the perfusion defect scores in the diltiazem group (+0.1 +/- 3.0 placebo vs -2.2 +/- 1.9 diltiazem, p less than 0.02) and a better ejection fraction recovery in the diltiazem group (-4.2 +/- 7.4 placebo vs +7.7 +/- 11.2 diltiazem, p less than 0.05). Myocardial infarct size estimates from perfusion defect scores and enzyme data were closely correlated. These preliminary results suggest that diltiazem may reduce ischemic injury in acute mazem may reduce ischemic injury in acute myocardial infarction

237

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

International Nuclear Information System (INIS)

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.)

238

[{sup 201}Tl](III)-bleomycin for tumor imaging  

Energy Technology Data Exchange (ETDEWEB)

Due to interesting physical properties and wide availability of thallium-201 as a SPECT radionuclide, the idea of incorporation of this nuclide into biologically active compounds was targeted. Thallium-201 (T{sub 1/2} = 3.04d) in Tl{sup +} form was converted to Tl{sup 3+} cation in presence of O{sub 3} in 6 M HCl controlled by RTLC/gel electrophoresis methods. The final evaporated activity was reacted with bleomycin in normal saline to yield [{sup 201}Tl]BLM at room temperature after 0.5 h (radiochemical yield > 999%) followed by HPLC analysis. The studies showed that thallic ion is mostly incorporated into bleomycin A{sub 2} while other species in the pharmaceutical sample almost remain unlabeled. Radiochemical purity of more than 99% was obtained using RTLC, HPLC with specific activity of about 7 Ci/mmol. The stability of the tracer was checked in the final product in presence of human serum at 37 C up to 3 d. The tracer accumulated in tumors of fibrosarcoma-bearing mice after 72 h. (orig.)

Jalilian, A.R.; Akhlaghi, M.; Shirazi, B.; Aboudzadeh, R.; Raisali, G.; Salouti, G.; Babaii, M. [Cyclotron and Nuclear Medicine Dept., Nuclear Research Center for Agriculture and Medicine, Karaj (Iran)

2006-07-01

239

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

240

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

International Nuclear Information System (INIS)

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)

 
 
 
 
241

Indium-111 antimyosin antibody imaging and thallium-201 imaging. A comparative myocardial scintigraphic study using single-photon emission computed tomography in patients with myocarditis and dilated cardiomyopathy  

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Indium-111 antimyosin antibody imaging (a tracer of myocardial necrosis) and thallium-201 imaging (a tracer of myocardial perfusion) were compared in patients with myocarditis and dilated cardiomyopathy. The distribution of each tracer and antimyosin/thallium-201 overlapping were evaluated with single-photon emission computed tomography (SPECT). Scintigraphic data were classified into 5 patterns according to the distribution of both images and were compared with histologic findings of endomyocardial biopsy: AM-D, intense and diffuse antimyosin uptake and no perfusion abnormality (active myocarditis); AM-L, localized antimyosin uptake and no perfusion abnormality (active myocarditis); HM, no antimyosin uptake with or without perfusion abnormality (healed myocarditis); DCM-NH, diffuse antimyosin uptake and inhomogeneous thallium-201 uptake (dilated cardiomyopathy); DCM-PD, diffuse or localized antimyosin uptake and myocardial perfusion defect(s) (dilated cardiomyopathy). Patients with dilated-phase hypertrophic cardiomyopathy were frequently found in the DCM-PD group. Taken together, comparative antimyosin/thallium-201 SPECT images are useful for evaluating the activity of myocarditis and ongoing myocardial damage even in areas with no perfusion in patients with dilated cardiomyopathy. (author)

Yamada, Takehiko; Matsumori, Akira; Nohara, Ryuji; Konishi, Junji; Sasayama, Shigetake [Kyoto Univ. (Japan). Faculty of Medicine; Tamaki, Nagara

1997-10-01

242

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

International Nuclear Information System (INIS)

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

243

Clinical usefulness of the 201Tl-chloride scintigraphy in the chronic thyroiditis  

International Nuclear Information System (INIS)

The thyroid scintigraphy with 123I and 201Tl-Chloride was performed for 32 patients with clinically proven chronic thyroiditis. Iodine-123 scintigrams showed varicus appearances, which were diffusely enlarged, mottled, cold nodullar and non visualizing patterns. The mottled pattern was the most common and seen in 16 out of 32 patients (50%). On the other hand, the 201Tl early scintigram performed within 15 minutes after intravenous injection demonstrated homogeneous high activity in the whole thyroid gland and in the 201Tl delayed scintigram performed 3 hours after the injection, the accumulation of 201Tl remained in the whole thyroid gland relatively strong compared to the background activity. The possibility to detect coexisting thyroid carcinoma in the chronic thyroiditis was described. Differential points between chronic thyroiditis and analplastic carcinoma involving whole thyroid gland in which thyroid gland was not visualized with 123I scintigram was discussed. We believe that 201Tl-early and delayed scintigrams could be one of useful non-invasive methods to diagnose chronic thyroiditis. (author)

244

Comparison of 201Tl-chloride and 67Ga-citrate in thyroid tumor scintigraphy  

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Twenty-five patients with thyroid tumors were examined by 201Tl-chloride and 67Ga-citrate scintigraphy heterochronously. All cases showed the cold nodule with 131I or sup(99m)Tc-pertechnetate thyroid scintigraphy. In 15 cases of thyroid carcinoma, 12 (80%) were positive by 201Tl-chloride; 4 (26.7%) were powitive by 67Ga-citrate. /In 10 patients with thyroid adenoma, 3 (30%) showed a positive figure by 201Tl-chloride. Histologically, these were all tubular adenoma, but in all cases of thyroid adenoma 67Ga-citrate revealed a negative figure. Tumors showing a positive figure by 201Tl-chloride that elicited negative results using 67Ga-citrate proved to be differentiated carcinoma or low differentated types of adenoma. Surgery is indicated in these cases. All of the tumors revealing a positive figure by 67Ga-citrate were highly malignant types. If these tumors showed a negative figure when 201Tl-chloride was used, undifferentiated carcinoma was suggested. In undifferentiated carcinoma, 67Ga-citrate scintigraphy is a useful procedure in locating distant metastases, in determining the area to be irradiated, and in judging the effect of therapy. (J.P.N.)

245

Quantification of left ventricular size on exercise thallium-201 single-photon emission tomography  

International Nuclear Information System (INIS)

The purposes of this study were to determine whether quantification of the left ventricular size on exercise thallium-201 single-photon emission tomography (SPET) correlates with echocardiographic measurements, whether the quantification reflects the severity of coronary artery disease, and whether it can provide supplementary information regarding the severity of coronary artery disease. In 42 control subjects and 110 patients who underwent coronary angiography, we performed exercise 201Tl SPET and quantified six non-regional markers: Lung 201Tl uptake on an initial planar image (Lung/Heart), left ventricular width on a tomogram (Width), change in the Width from the initial to delayed tomograms (?Width), count ratio of the left ventricular cavity to the myocardium (C/M), count ratio of the lung to the myocardium (L/M), and count ratio of the lung to the left ventricular cavity (L/C). In 76 patients, furthermore, the Width was compared with echocardiographic measurements. The Width correlated with echocardiographic measurements (P201Tl SPET correlated with echocardiogrpahic measurements and reflected the severity of coronary artery disease, but may be replaced with quantitation of the lung 201Tl uptake. (orig.)

246

Prognostic value of post-ischemic stunning as assessed by gated myocardial perfusion single-photon emission computed tomography. A subanalysis of the J-ACCESS study  

International Nuclear Information System (INIS)

To determine the prognostic value of post-ischemic stunning, the Japanese assessment of cardiac event and survival study by quantitative gated myocardial single-photon emission computed tomography (SPECT) (J-ACCESS) study was reevaluated. Of the 4,031 patients of the J-ACCESS, the present study evaluated 1,089 who completed gated SPECT both after stress and at rest. To assess post-ischemic stunning, the following measurements (left ventricular volumes after stress minus volumes at rest) were made: ?end-systolic volume (?ESV), ?end-diastolic volume (?EDV) and ?ejection fraction (?EF). Myocardial stunning defined either as ?ESV ?5 ml, ?EDV ?5 ml or ?EF ?-5% was observed in 21%, 22%, or 26%, respectively. During a 3-year follow-up, 101 cardiac events occurred. Kaplan-Meier survival estimation indicated worse event-free survival rates in patients with dilated ESV, dilated EDV, left ventricular ejection fraction (LVEF) ?45% ?ESV ?5 ml or ?EDV ?5 ml than in those without, whereas ?EF ?-5% did not predict events. Multivariate analysis demonstrated that LVEF ?45% was the independent predictor for cardiac events. Nevertheless, ?EDV ?5 ml was also an independent parameter, in addition to LVEF ?45%, to predict the combined endpoint of cardiac death, myocardial infarction, and revascularization, but excluding heart failure. These results indicate that post-ischemic stunning, as assessed by gated SPECT, is a marker for poor prognosis, particularly for ischemic cardiac events. (author)

247

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

International Nuclear Information System (INIS)

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

248

Proton induced reactions on natural Pb targets. A potential new cyclotron method for 201Tl production  

International Nuclear Information System (INIS)

The basis for a new cyclotron method for production of no-carrier-added 201Tl, from its grandparent 201Bi via the Pb(p,xn)201Bi ? 201Pb ? 201Tl reaction is presented here. Thick-target yields (?Ci/?Ah) for the 201Pb and 200Pb induced radioactivities were measured over the 65- to 43-MeV proton-energy range. The experimental data indicate that the 201Tl yields could be optimized by using Pb targets enriched in 206Pb, 207Pb, and, or 208Pb, which are expected to provide greater overall yields than current methods, as well as material of high-chemical, radiochemical and radionuclidic quality for radiopharmaceutical production. (author)

249

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

International Nuclear Information System (INIS)

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

250

201Tl-SPECT, 1H-MRS, and MIB-1 labeling index of central neurocytomas: three case reports  

International Nuclear Information System (INIS)

Background: The proliferative activity and metabolic features of three central neurocytomas were investigated using the findings of thallium-201 single photon emission computed tomography (201Tl-SPECT) and proton magnetic resonance spectroscopy (1H-MRS), and the MIB-1 labeling index (MIB-1 LI). Method: The early and delayed 201TI indices were calculated as the ratio of tumor to normal brain tissue uptake by 201TI-SPECT. In vivo single-voxel 1H-MRS was performed with echo time of 272 msec to evaluate the metabolites including choline (Cho), N-acetyl aspartate (NAA) and creatine/phosphocreatine (Cre). An external standard reference was used to semiquantitate each metabolite. MIB-1 LI was determined in the surgical specimens. Findings: The MIB-l LI was 0.5 %, 1.2 %, and 7.5 % in an atypical central neurocytoma without intraventricular extension. Significant 201TI uptake was observed on delayed images in all three central neurocytomas. 1H-MRS showed the high Cho peaks relative to the NAA and Cre peak. The signal at 3.55 ppm, which may be due to inositol or glycine, was observed in one central neurocytoma. Interpretation: Both 201TI-SPECT and 1H-MRS did not reflect the proliferative potential of central neurocytomas. (author)

251

The study of 201Tl, 123I-IMP-SPECT before and after radiation therapy for brain tumor  

International Nuclear Information System (INIS)

201Tl, 123I-IMP-SPECT were performed in 17 patients with brain tumors before and after radiation therapy, compared with X-CT. 15 of 17 patients showed enhanced areas on X-CT and higher accumulation on 201Tl-SPECT in the same lesions before radiation therapy. There was significant correlation between enhanced lesions on X-CT and lesions of higher accumulation on 201Tl-SPECT before and after radiation therapy. But, the patients with residual enhanced lesions on X-CT did not always show higher accumulation on 201Tl-SPECT after radiation therapy. And, 2 patients with radiation injury after radiation therapy for brain tumor did not show higher accumulation on 201Tl-SPECT, though one patient showed enhanced lesion on X-CT. 201Tl-SPECT was expected to evaluate viability of brain tumor. 123I-IMP-SPECT was useful to recognize the site of higher 201Tl accumulation and evaluate blood flow around brain tumor. It is concluded that 201Tl, 123I-IMP-SPECT is useful for the evaluation of treatment effect of brain tumor and for the differentiation of cerebral radiation injury from recurrent tumor. (author)

252

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

International Nuclear Information System (INIS)

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.

253

{sup 201}Tl /{sup 99m}Tc Subtraction Scan in the Diagnosis of Hyperparathyroidism  

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{sup 201}Tl /{sup 99m}Tc 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. {sup 201}Tl /{sup 99m}Tc pertechnetate scan was useful for patients with hyperparathyroidism, especially in definite localization preoperatively.

Ahn, Bo Young; Sohn, Hyung Sun; Kim, Euy Neyung; Kim, Sung Hoon; Chung, Soo Kyo; Kim, Choon Yul; Baek, Yong Whee; Shinn, Kyung Sub [Catholic University College of Medicine, Seoul (Korea, Republic of)

1995-09-15

254

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

International Nuclear Information System (INIS)

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)

255

Estimation of Myocardial Ischemia by Diastolic Strain Analysis in Exercise Stress Echocardiography. Comparison with exercise thallium-201 single photon emission computed tomography  

International Nuclear Information System (INIS)

The feasibility of detecting persistent regional left ventricular abnormal relaxation due to myocardial ischemia using strain echocardiography several minutes after exercise was investigated. Consecutive 27 patients (mean age 65±9 years, 21 males, 6 females) with suspected coronary artery disease were enrolled. Strain echocardiographic images were acquired at the mid segments of the left ventricular wall before and 5 min after exercise in the apical long-axis, two-chamber and four-chamber views. Strain curves were obtained at each segment, and peak values of strain at the closure of aortic valve (A) and at one third of diastolic duration (B) were measured. Strain diastolic index (SDI) was calculated as (A-B)/A x 100%. The ratio of SDI before exercise to that after exercise was defined as the SDI ratio and compared with exercise thallium-201 single photon emission computed tomography (SPECT) as the reference standard to detect myocardial ischemia. A total of 162 segments were evaluated. Based on the results of exercise SPECT, 119 segments were classified as non-ischemic segments, and 43 as ischemic segments. Ischemic segments showed significant decreases in SDI before and after exercise, whereas non-ischemic segments showed no significant differences in SDI before and after exercise. SDI ratio was significantly decreased in ischemic segments, but not in non-ischemic segments. SDI ratio with a cut off value of 0.51 had a sensitivity of 91% and a specificity of 89% to dvity of 91% and a specificity of 89% to detect myocardial ischemia in the receiver-operating characteristics. Strain echocardiography can provide quantitative assessment of myocardial ischemia by detecting post-ischemic regional left ventricular delayed relaxation even 5 min after exercise. (author)

256

Effects of exercise on kinetics and distribution of 43K and 201Tl in isolated myocardium: concise communication  

International Nuclear Information System (INIS)

Kinetics and distribution of K-43 and Tl-201 were studied in isolated myocardial tissue from rats to assess the effects of exercise. The experimental design was as follows. Rats in some groups were forced to swim for 2 hr; immediately after swimming, they were injected with 0.2 mCi of 43KCl or 201TlCl; at 0.5 or 3 hr after injection they were killed and a myocardial segment was obtained and subjected to washouts with nonradioactive Krebs fluid in a special chamber. The radioactivity remaining in the tissue was recorded continuously for 1 hr. In control groups (''rested'') the exercise was omitted. Altogether there were four groups of ten animals each for both K-43 and Tl-201. A three-compartment model (extracellular, main intracellular, and subcellular) was used; transport rate constants and relative compartment sizes were determined. The most striking finding was the unchangeability of K-43 parameters with regard to experimental condition (rest compared with exercise) and sampling time (0.5 compared with 3 hr after radionuclide injection). On the other hand, Tl-201 parameters were modified by exercise and sampling time. Notable differences between K-43 and Tl-201 kinetics were found. The hypothesis that alterations at the cellular level may affect regional myocardial distribution of a radionuclide is discussed

257

On the generation of short-axis and radial long-axis slices in thallium-201 myocardial perfusion single-photon emission tomography  

International Nuclear Information System (INIS)

We tried to develop fully automatic reorientation algorithms in thallium-201 myocardial perfusion single-photon emission tomography, and tested a method to evaluate the quality of reorientation. The left ventricle was automatically segmented using count density information, contours generated with Laplacian operators in both transaxial and sagittal slices, and morphological and positional characteristics of the contours. Reorientation was automatically performed based on knowledge of the long axis of a second degree surface fitted to the myocardial wall. We tried to achieve improvement in reorientation without relying on any functional description of left ventricular shape. Quality of reorientation was evaluated and improved using interactive tools in combination with radial long-axis slices. Two groups of 50 patients, after stress and rest, were analysed using the traditional manual and the fully automatic procedures. Automatic segmentation was successful in 98 out of 100 cases, and automatic reorientation was of reasonable quality. Reorientation obtained with the radial long-axis slices tool was better than after traditional manual or automatic reorientation. Automatic reorientation based on second degree surface fitting was in our hands less successful than reported in the literature. The tool using radial long-axis slices provides a better standard for testing reorientation algorithms than the traditional manual method. (orig.)rig.)

258

Effects of exercise training on myocardial fatty acid metabolism in rats with depressed cardiac function induced by transient ischemia  

International Nuclear Information System (INIS)

The effects of exercise training on metabolic and functional recovery after myocardial transient ischemia were investigated in a rat model. Male Wistar Kyoto rats were subjected either to a 30-min left coronary artery occlusion followed by reperfusion or to a sham operation. At 4 weeks after operation, the rats were randomly assigned either to sedentary conditions or to exercise training for 6 weeks. In the ischemic rats, pinhole SPECT (single photon emission computed tomography) imaging with thallium-201 (201Tl) and 123I-(?-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) showed a reduction of both myocardial perfusion and fatty acid metabolism in the risk zone of the left ventricle (LV). The LV was dilated and the ejection fraction was decreased after ischemic injury. The severity score showed a significant decrease on both 201Tl and BMIPP (201Tl, from 19.9±2.7 to 17.0±2.2, p<0.05; BMIPP, from 21.5±2.4 to 18.6±1.9, p<0.05) after exercise training in the ischemic trained rats, but did not change significantly in their sedentary counterparts. Plasma levels of free fatty acids normalized in the ischemic trained rats, but elevated in the ischemic sedentary rats (0.53±0.05 vs 0.73±0.06 mmol/L, p<0.05). Furthermore, the trained rats had a significant increase in LV stroke volume (0.25±0.02 vs 0.21±0.01 ml/beat, p<0.05) and adaptive cardiac hypertrophy. These findings demonstrate that adaptive improvements in myocardial perfusion, fatty-acid metabolism and LV function were induced by exercise training after transient ischemia. (author)

259

Usefulness of acute myocardial infarct size and localization using Tc-99m-pyrophosphate and single photon emission computed tomography  

International Nuclear Information System (INIS)

Tc-99m-Pyrophosphate(PYP)myocardial emission computed tomography(ECT) was performed following standard planar imaging in 45 patients(pts) with acute myocardial infarction(AMI). All of them had clinical, electrocardiographic and enzymatic evidence of AMI. The planar imaging and ECT imaging were interpreted independently by two observers who had no knowledge of the clinical findings. 10 pts(22.2 %), who showed diffuse uptake on planar imaging, revealed focal uptake on ECT imaging without cardiac blood pool imaging. And there is no disagreement as to interpretation of the infarct location by two observers on ECT imaging. We conclude that ECT imaging with Tc-99m-PYP increases interobserver agreement in the diagnosis and localization of AMI and may lead to more accurate localization and sizing of AMI, espesically in cases of diffuse cardiac activity on planar imaging. (author)

260

Usefulness of rapid low-dose/high-dose 1-day 99mTc-sestamibi ECG-gated myocardial perfusion single-photon emission computed tomography  

International Nuclear Information System (INIS)

The clinical usefulness of a rapid rest low-dose/stress high-dose (dose ratio=1:5) 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) protocol for the detection of coronary artery disease was evaluated. In 89 patients, rest images were obtained immediately after the injection of 99mTc-sestamibi (256.1±28.4 MBq) followed by drinking water (400 ml). Exercise or vasodilator stress test was performed immediately after the completion of rest imaging with the injection of 99mTc-sestamibi (1312.3±167.6 MBq). Prior to the post-stress imaging, patients were asked again to drink water (400 ml) in order to eliminate subdiaphragmatic tracer activity. The myocardial count ratio (stress/rest) of 99mTc-sestamibi was calculated. Image quality was scored using a 4-point scale system (4=excellent, 3=good, 2=poor, 1=unacceptable). Coronary angiography was performed in 56 patients within 1 month of the SPECT scan. All patients successfully performed the protocol and total examination time was 108±7 min. The myocardial count ratio of 99mTc-sestamibi was always greater than 6. The image quality was satisfactory both at rest (3.4±0.9) and after stress (3.9±0.2). The sensitivity and specificity to detect coronary artery stenosis >50% was 84% and 97%, respectively. This rapid one-day 99mTc-sestamibi protocol provides adequate image quality and diagnostic accuracy for detectin and diagnostic accuracy for detecting coronary artery disease. (author)

 
 
 
 
261

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

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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 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.) With 1 fig., 26 tabs., 22 refs.

Bartram, P.; Hanel, B.; Gustafsson, F.; Mortensen, J.; Hesse, B. [Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital (Denmark); Toft, J. [Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital (Denmark)]|[Copenhagen City Heart Study, Epidemiological Research Unit (Denmark); Ali, S. [Dept. of Cardiology, Copenhagen University Hospital (Denmark)

1998-09-01

262

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.)

263

Application of transmission scan-based attenuation compensation to scatter-corrected thallium-201 myocardial single-photon emission tomographic images  

International Nuclear Information System (INIS)

A practical method for scatter and attenuation compensation was employed in thallium-201 myocardial single-photon emission tomography (SPET or ECT) with the triple-energy-window (TEW) technique and an iterative attenuation correction method by using a measured attenuation map. The map was reconstructed from technetium-99m transmission CT (TCT) data. A dual-headed SPET gamma camera system equipped with parallel-hole collimators was used for ECT/TCT data acquisition and a new type of external source named ''sheet line source'' was designed for TCT data acquisition. This sheet line source was composed of a narrow long fluoroplastic tube embedded in a rectangular acrylic board. After injection of 99mTc solution into the tube by an automatic injector, the board was attached in front of the collimator surface of one of the two detectors. After acquiring emission and transmission data separately or simultaneously, we eliminated scattered photons in the transmission and emission data with the TEW method, and reconstructed both images. Then, the effect of attenuation in the scatter-corrected ECT images was compensated with Chang's iterative method by using measured attenuation maps. Our method was validated by several phantom studies and clinical cardiac studies. The method offered improved homogeneity in distribution of myocardial activity and accurate measurements of myocardial tracer uptake. We conclude that the above correction method is feasible because a new trection method is feasible because a new type of 99mTc external source may not produce truncation in TCT images and is cost-effective and easy to prepare in clinical situations. (orig.)

264

Evaluation of 201Tl-DDC as a cerebral blood flow tracer  

International Nuclear Information System (INIS)

We studied rCBF in 28 patients (cerebrovascular disease, epilepsy, migraine, dementia) by means of 201Tl-DDC (Diethyldithiocarbamate) and SPECT and, for comparison, all patients underwent also a control SPECT study with IMP or HMPAO. DDC-SPECT images are comparable to SPECT images using IMP or HMPAO. In addition, DDC seems to offer some advantages. (orig./MG)

265

Physiologic basis and utility of myocardial perfusion imaging  

International Nuclear Information System (INIS)

Myocardial imaging with 201Tl+ allows improved detection of coronary artery disease. The distribution of 201Tl+ in heart muscle is related primarily to blood flow and cellular integrity. Serial imaging of 201Tl+ heart muscle distribution demonstrates gradual fill in of initial 201Tl+ defects which are due to ischemia (reduced blood flow and/or increased metabolic demand), and persistence of defects which are due to acute infarct or scar. Improvement in radionuclide detection or coronary artery disease will likely occur over the next decade through: (1) computer approaches to quantification of serial changes in 201Tl+ distribution; (2) gamma camera tomographic approaches using multiaperture collimators; (3) addition of the multigated acquisition blood pool imaging approaches; (4) application of positron transverse section emission tomography; and (5) development of other radiopharmaceuticals

266

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)

267

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 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)

268

Reversible myocardial ischaemia or irreversible myocardial fibrosis  

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

269

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 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.)

270

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

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Prolonged and persistent myocardial stunning has recently been demonstrated using technetium-99m sestamibi gated single-photon emission tomography (SPET) myocardial perfusion imaging post exercise or pharmacological stress test. In this study, we investigated the early postischemic transient myocardial stunning on early and delayed poststress thallium-201 gated SPET myocardial perfusion imaging using segmental wall motion (WM) and wall thickening (WT) analysis. A total of 1,680 segments from 84 patients' studies (53 men and 31 women, mean age 60 years) were evaluated on both early and delayed thallium-201 gated SPET treadmill exercise (59) or dobutamine stress (25) myocardial perfusion imaging. Semiquantitative analysis of perfusion, WM and WT in all segments was performed by two observers. Segments were classified according to changes in WM and WT between early and delayed images into normal, fixed abnormality, or improved abnormality (transient stunning), and were further classified according to changes in perfusion into normal, fixed defects, or ischemic. There were significant correlations between perfusion and WM, perfusion and WT, and WM and WT segmental scores on both early and delayed images. Transient stunning was seen significantly (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.)

271

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

International Nuclear Information System (INIS)

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

272

Superconducting Single Photon Detectors:  

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This thesis is about the development of a detector for single photons, particles of light. New techniques are being developed that require high performance single photon detection, such as quantum cryptography, single molecule detection, optical radar, ballistic imaging, circuit testing and fluorescence spectroscopy. Superconducting single photon detectors (SSPDs) are sensitive to single photons from the ultraviolet to the near infrared. In this thesis steps has been taken towards improvi...

Dorenbos, S. N.

2011-01-01

273

Myocardial scintigraphy and radionuclide ventriculography in myocardial infarction  

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

274

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

International Nuclear Information System (INIS)

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

275

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

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

276

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

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

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

2013-07-15

277

Cardiac manifestations of malignant hyperthermia susceptibility. [/sup 201/Tl scintiscanning  

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Malignant hyperthermia is a disease resulting from defective cellular membranes, usually presenting as drug-induced pyrexic crises. We describe four patients with life threatening ventricular arrhythmias or chest pain in the absence of pyrexic crises. Three presented with life threatening arrhythmias and the fourth with severe atypical chest pain. Two patients had a family history of multiple sudden deaths. Resting CKs were elevated in three patients while CK-MB was elevated in one. Resting ECGs were abnormal in three. Three patients had recurrent ventricular tachycardia, two had recurrent ventricular fibrillation and multiple cardiac arrests. Cardiac catheterization showed abnormal left ventricular wall motion in two and minimal mitral valve prolapse in one while all had normal coronary arteries. Thallium-201 myocardial imaging demonstrated large perfusion defects in the patient with electrocardiographic Q waves and normal coronary arteries. Myocardial involvement has been demonstrated by clinical, electrocardiographic, hemodynamic, angiographic and myocardial imaging abnormalities. Malignant arrhythmias occurred in these patients in the absence of pyrexic crises or drug administration. Abnormal calcium release in the myocardium, as documented in skeletal muscle membranes, may be a unifying concept for the various manifestations described.

Huckell, V.F.; Staniloff, H.M.; Britt, B.A.; Waxman, M.B.; Morch, J.E.

1978-11-01

278

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

International Nuclear Information System (INIS)

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

279

Assessment of tumor viability by 201Tl SPECT in VX-2 tumor-bearing rabbits after irradiation. Comparison with X-ray CT and pathohistologic findings  

International Nuclear Information System (INIS)

In order to evaluate 201Tl SPECT for the assessment of tumor viability after radiation therapy, twenty rabbits were implanted with VX-2 tumor in the left femoral muscles and were classified into four groups as follows: normal control group (N), 20 Gy irradiated response group (A), 20 Gy irradiated non-response group (B), and 40 Gy irradiated group (C). Eight days after implantation, 201Tl SPECT and CT studies were performed to assess the changes in 201Tl uptake and tumor volume at 0, 1, 2, 3, and 4 weeks after single irradiation. Histologic specimens were also taken. In group N tumors continued to increase in volume, but 201Tl uptake showed a steady decrease after 2 weeks. In group A tumors continued to increase in volume, but 201Tl uptake showed a transient decrease at 2 weeks, then a steady increase. In group B tumors showed a transient increase in volume at 2 weeks, then a continuous decrease, but 201Tl uptake showed a continuous decrease throughout the study. In group C there was a continuous decrease both in volume and 201Tl uptake with the later more prominent. 201Tl uptake was decreased earlier than tumor volume both in groups B and C, at one week that was significant (p201Tl uptake by tumor reflects the burden of viable tumor on histology; therefore 201Tl SPECT is of great use in assessing the therapeutic effects on tumors. (author)

280

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

 
 
 
 
281

Difference in 201TlCl accumulation mechanism in brain tumors. A comparison of their Na+-K+ ATPase activities  

International Nuclear Information System (INIS)

The accumulation levels of 201TlCl and Na+ -K+ ATPase activity in tumor tissue were compared among glioblastoma, benign glioma and meningioma to study the difference in the mechanism of 201TlCl accumulation. The subjects were 19 cases comprised of 6 glioblastoma, 2 oligodendroglioma, 1 fibrillary astrocytoma, 1 pilocytic astrocytoma and 9 meningioma. Preoperative 201TlCl SPECT was performed in all the cases, and Thallium Index (TL index) was calculated by a ratio of 201TlCl in the tumor area and the contralateral area. In addition, cell membrane was extracted from the tumor tissue collected intraoperatively to determine Na+ -K+ ATPase activity. No statistically significant difference in TL index was noted between the glioblastoma group (6.97±2.67) and the meningioma group (5.87±1.99). This fact showed that there was no difference in the accumulation level of 201TlCl between the two groups. On the other hand, the glioblastoma group indicated a higher value of Na+ -K+ ATPase activity (49.13±43.76 ?mole/hour/mg protein) than the meningioma group (7.73±13.84 ?mol/hour/mg protein) (p+ -K+ ATPase activity in 201TlCl accumulation in glioblastoma and the influences of other accumulation mechanism than Na+ -K+ ATPase activity such as the + ATPase activity such as the volume of intratumoral vascular bed in meningioma. (author)

282

Diagnosis of pancreatic cancer using 201Tl-chloride and a three-head rotating gamma camera SPECT system  

International Nuclear Information System (INIS)

201Tl SPECT was performed on 17 patients with pancreatic cancer or chronic pancreatitis using a three-head rotating gamma camera SPECT system. In 7 of 10 patients with pancreatic cancer, the lesions were clearly delineated by 201Tl SPECT. Whereas the lesion of 30 mm in diameter was visualized, a large tumor of 80 mm in diameter could not be visualized. Namely, it was thought that 201Tl uptake by pancreatic cancer might be well correlated with tumor blood flow and/or its histological subtype rather than with tumor size. In 5 of 7 patients with chronic pancreatitis, no uptake by the pancreas was shown. The sensitivity, specificity, and accuracy in diagnosing pancreatic cancer by 201Tl SPECT were 70%, 71%, and 71%, respectively. The present results obtained by 201Tl SPECT were thought satisfactory enough to evaluate pancreatic cancer under the present conditions where there was no useful imaging agent for visualizing pancreatic cancer by SPECT. 201Tl SPECT is expected to be a new diagnostic tool for investigation of pancreatic tumorous lesion. (author)

283

Nuclear excitation in the reaction 207Pb(?-,?6n)201Tl  

International Nuclear Information System (INIS)

A probability of roughly 1% has been measured for the formation of the first excited state of 201Tl following muon capture on 207Pb. A probability of this magnitude for 6 neutron emission may indicate structure in the nuclear excitation function near 54 MeV. An alternative interpretation is provided by muon capture on a correlated np pair in analogy with pion absorption. (orig.)

284

Single photon emission computed tomography (SPECT)  

International Nuclear Information System (INIS)

The functional state of organs can be imaged by their accumulation of single photon emitter like 99mTc (?-ray energy 140 keV), 201Tl (73 keV) and 201I (159 keV) with computed tomography. The emitted ?-ray is collimated to reach the NaI (Tl) detector for specifying its direction, which is called as the scintillation camera or gamma camera. The camera rotating around the patient gives the SPECT images. The NaI (Tl) detector is suitable for converting 60-300 keV ?-ray to fluorescence through the photoelectric effect. Photomultiplier receiving the fluorescence outputs X/Y signals for the emitting position and Z signal (energy) separately, giving imaging data. 3D images can be re-constructed by either method of the filtered back projection or maximum likelihood-expectation maximization. For quantitative reconstruction, correction of ?-ray absorption in water, of scattering and of collimator opening is necessary. Recently, semiconductor-detectors like CdZnTe and CdTe are being utilized in place of NaI for better resolution, which will reduce the size of the camera. Further, a camera with coincidence circuit for positron has appeared and will be applicable for both SPECT and PET. Compton camera having 2-step detectors without collimator is now under development. (N.I.)

285

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

286

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)

287

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

International Nuclear Information System (INIS)

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

288

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

International Nuclear Information System (INIS)

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

289

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

290

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

291

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

292

Evaluation of 201TlCl per rectum scintigraphy in biliary atresia  

International Nuclear Information System (INIS)

To study whether or not 201TlCl per rectum scintigraphy is clinically useful for evaluating portosystemic shunt in biliary atresia (BA), we reviewed 13 patients with biliary atresia already in the postoperative state. The patients' details were as follows: age, 4 years 6 months-18 years 7 months (mean: 12 years 7 months); male, 3 cases; females, 10 cases; type III BA, 11 cases; type I-cyst BA, 2 cases. A radioisotope (RI) of 201TlCl (18.5 or 37.0 MBq) was administered via the rectum. Heart and liver counts per area were calculated respectively 30-60 minutes after RI administration, and the ratio of heart and liver (H/L ratio) was adopted as a indicator of portosystemic shunt. There was no correlation between the H/L ratio and laboratory examinations (total bilirubin, alanine aminotransferase, cholinesterase, white blood cell and platelet). There was positive correlation between the H/L ratio and splenomegaly. Splenomegaly was evaluated using gray-scale ultrasonography. There was a positive correlation between the H/L ratio and existence of esophageal varices. Esophageal varices were evaluated using barium meal upper gastrointestinal examination. There was a remarkable positive correlation between the H/L ratio and the patient's age. This group of patients was restricted to that in which the laboratory liver function test was abnormal. The use of 201TlCl via rectum scintigraphy and quantitatively conducted H/L ratio are clinically usefuy conducted H/L ratio are clinically useful for evaluating the portosystemic shunt in biliary atresia. The portosystemic shunt might gradually increase with patients' age independently of the liver function, which should support our daily clinical observations. (author)

293

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.)

294

Assessment of viability by quantitative evaluation of 24h-redistribution in 201-thallium myocardial scintigraphy (SPECT): A comparative study versus clinical follow-up after revascularisation. Vitalitaetsbeurteilung mittels der 24h-Resdistribution in der quantitativen 201-Tl-Myokardszintigraphie (SPECT) im Vergleich zur klinischen Langzeitkontrolle nach Intervention  

Energy Technology Data Exchange (ETDEWEB)

Results of regional quantitative assessment of 24h-redistribution in routinely performed Thallium myocardial scintigraphy (SPECT) were compared to findings of coronary angiography/ventriculography and/or echocardiography as well as clinical status 6 months after revascularisation in up to now 34 patients. In respect of positive and negative predictive values evaluation of 24h-redistribution behaves best (81/100%) compared to perfusion and 3h-redistribution alone. Performing an additional 24h-study gives a gain of at least 80% of diagnostic information. (orig.).

Stirner, H.; Spreng, M.; Picker, D. (Klinikum Ingolstadt, Inst. fuer Nuklearmedizin (Germany)); Pfafferott, C. (Klinikum Ingolstadt, 1. Medizinische Klinik (Germany))

1992-06-01

295

Single photon ECT  

International Nuclear Information System (INIS)

The detectability of lesions located deep in a body or overlapped with a physiologically increased activity improve with the help of single photon ECT. In some cases, the ECT is superior to the conventional gamma camera images and X-ray CT scans in the evaluation of the location and size of lesion. The single photon ECT of the brain compares favorably with the contrast enhansed X-ray CT scans. The most important adaptation of the single photon ECT are the detection of recurrent brain tumors after craniotomy and the evaluation of ischemic heart diseases. (author)

296

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

International Nuclear Information System (INIS)

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

297

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)

298

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 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)

299

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)

300

Estimation of malignancy using SPECT with [sup 201]Tl chloride in astrocytic tumors  

Energy Technology Data Exchange (ETDEWEB)

This study was designated to estimate the usefulness of SPECT with [sup 201]Tl chloride (Tl-SPECT) for the determination of the malignancy in astrocytic tumors. The subjects consisted of 39 astrocytic tumors in supra-tentorial regions. Tl-SPECT undertaken ten minutes to obtain an early image and four hours to obtain a delayed image, after intravenous injection of 74 MBq [sup 201]Tl chloride (Tl). Tl index (L/N) was defined as the RI count ratio in the tumor lesion (L) to that in the normal parenchyma (N). Histological classification was determined by the WHO grading, and the results showed one case at Grade I, 11 cases at Grade II, 23 cases at Grade III and 4 cases at Grade IV. The proliferating activity was determined by the labeling index using the monoclonal antibody of proliferating cell nuclear antigen (PCNA). In both of the early and delayed images, Tl index was significantly higher (p<0.01) in high grade astrocytomas compared with low grade tumors. There was a close correlation between the Tl index and the proliferating activity. The relationship between the Tl index and prognosis indicated that the high Tl index corresponded to the poor prognosis. These results showed that the Tl index is useful to determine the malignancy of astrocytic tumors. (author).

Seo, Hiroshi; Fujita, Toshiya; Nakai, Osamu; Komatani, Akio (Yamagata Univ. (Japan). School of Medicine)

1994-02-01

 
 
 
 
301

Estimation of malignancy using SPECT with 201Tl chloride in astrocytic tumors  

International Nuclear Information System (INIS)

This study was designated to estimate the usefulness of SPECT with 201Tl chloride (Tl-SPECT) for the determination of the malignancy in astrocytic tumors. The subjects consisted of 39 astrocytic tumors in supra-tentorial regions. Tl-SPECT undertaken ten minutes to obtain an early image and four hours to obtain a delayed image, after intravenous injection of 74 MBq 201Tl chloride (Tl). Tl index (L/N) was defined as the RI count ratio in the tumor lesion (L) to that in the normal parenchyma (N). Histological classification was determined by the WHO grading, and the results showed one case at Grade I, 11 cases at Grade II, 23 cases at Grade III and 4 cases at Grade IV. The proliferating activity was determined by the labeling index using the monoclonal antibody of proliferating cell nuclear antigen (PCNA). In both of the early and delayed images, Tl index was significantly higher (p<0.01) in high grade astrocytomas compared with low grade tumors. There was a close correlation between the Tl index and the proliferating activity. The relationship between the Tl index and prognosis indicated that the high Tl index corresponded to the poor prognosis. These results showed that the Tl index is useful to determine the malignancy of astrocytic tumors. (author)

302

Studies on muscle metabolism in peripheral vascular disease using 201Tl  

International Nuclear Information System (INIS)

Thallium 201 has been used mostly in cardiology, for the detection of ischemic ''areas'' and infarcted zones in cardiac muscle. This isotope has been chosen, because of its great metabolic similarity to Potassium. But less interest has been shown in the transit and localization of Thallium in the limbs. We have been working on a method based upon the study of muscle metabolism using 201Tl which could possibly detect the condition before the onset of clinical symptoms. As a preliminary investigation, we have studied the distribution of this isotope, in rats after effort, or in resting state. We have observed an important increase in the muscle uptake of 201Tl during the period of effort compared to the uptake in a resting state. The ratio of this increased uptake is about two to three times more important. In vitro studies of fibroblast cell cultures reveal a competition between potassium and thallium, the fixation of thallium being diminished in the presence of an excess of potassium and increased when the concentration of potassium is low, in the culture medium

303

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

304

Study to prepare 201Tl by irradiation of mercury with protons. Application of extraction chromatography technique in separation of thallium and mercury  

International Nuclear Information System (INIS)

The extraction chromatography technique was used for the lig and 201Tl separation. It was used glass columns of 5,0 cm height and 1,0 cm diameter filled with Voltalef powder impregnated with TBP/cyclohexane. By the Voltalef columns solutions of 203Hg2+, 201Tl1+ and 201Te3 were separately percolated in a nitric environment of 4 to 8 M concentration and in a hydrochloridric environment of 0,5 to 4 M. The separation of Hg and 201Tl was obtained by the retention of 201Tl3+ in the column during the elution of all the Hg with HCl 2 M. The 201Tl3+ was eluted from the column after its reduction with a hot hydrazine dichloride solution. (Author)

305

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 with 123I-BMIPP and 201Tl may provide a unique means of identifying patients with metabolically disturbed myocardium, such as hibernating and stunned myocardium. (author)

306

Single-photon imaging  

International Nuclear Information System (INIS)

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 uncooled 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 internationally renowned, leading scientists and technologists who have all pioneered their respective fields. (orig.)

307

Single-photon imaging  

Energy Technology Data Exchange (ETDEWEB)

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 uncooled 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 internationally renowned, leading scientists and technologists who have all pioneered their respective fields. (orig.)

Seitz, Peter [CSEM SA, Landquart (Switzerland); Theuwissen, Albert J.P. (eds.) [Technische Univ. Delft (Netherlands)

2011-07-01

308

[Gamma-ray spectra of 201Tl-radiopharmaceuticals with a scintillation camera--crosstalk of contaminating nuclides of 200Tl and/or 202Tl onto 201Tl-photopeaks].  

Science.gov (United States)

In cardiac imaging with 201Tl, the collimator for low energy high resolution is generally used, and also the energy window, which is set on the spectral display of a pulse height analyzer of a scintillation camera, is chosen 70 +/- 12.5 keV. The purpose of this study is to discuss those conditions in 201Tl imaging with the scintillation camera. Two types of collimators for HR (high resolution) and ME (medium energy) were used in this experiment, and we measured the pulse height spectra of 201TlCl radiopharmaceuticals in air and in a cuboid phantom, connecting a multi-channel pulse height analyzer to the scintillation camera. As a result of measuring of the pulse height spectra, two different energies of gamma rays which are not supposed to emit from 201Tl nuclide were observed, and we also identified the presence of a small amount of 202Tl (with 439 keV) and/or 200Tl (with 368 keV) from their half-life measurements. Thus, the use of the HR-collimator with 201Tl imaging is not suitable, because the shielding effects of its septa is poor to 439 keV gamma-rays, and the scattered radiation produced by the Compton interaction contributes to the principal photopeak on the pulse height spectrum. Here, we recommend the use ME-collimator instead of the HR-one, and of the window width of 76 +/- 25 keV for increasing the count rate. PMID:2396018

Saegusa, K; Fukushi, M; Katoh, Y; Saitoh, H; Irifune, T

1990-06-01

309

201Tl-SPECT in low-grade gliomas: diagnostic accuracy in differential diagnosis between tumour recurrence and radionecrosis  

International Nuclear Information System (INIS)

p>201Tl-SPECT has adequate diagnostic accuracy to be part of routine algorithms in the follow-up of patients with low-grade glioma suspected of tumour recurrence, as an alternative to neuro-anatomical procedures and not solely as a complementary test. (orig.)

310

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)

311

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

International Nuclear Information System (INIS)

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)

312

Single-photon tunneling  

CERN Document Server

Strong evidence of a single-photon tunneling effect, a direct analog of single-electron tunneling, has been obtained in the measurements of light tunneling through individual subwavelength pinholes in a thick gold film covered with a layer of polydiacetylene. The transmission of some pinholes reached saturation because of the optical nonlinearity of polydiacetylene at a very low light intensity of a few thousands photons per second. This result is explained theoretically in terms of "photon blockade", similar to the Coulomb blockade phenomenon observed in single-electron tunneling experiments. The single-photon tunneling effect may find many applications in the emerging fields of quantum communication and information processing.

Smolyaninov, I I; Gungor, A; Davis, C C

2001-01-01

313

Dual myocardial single photon emission computed tomography (SPECT) using thallium-201 and I-123-{beta}-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 {sup 123}I-{beta}-methyl pentadecanoic acid (BMIPP) for myocardial fatty acid metabolism and {sup 201}thallium (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<0.042). However, when Tl defect score was larger than BMIPP defect score, an increase in Tl defect score was slight. A significant negative correlation was found between the sum of the BMIPP and Tl defect scores and the left ventricular ejection fraction (LVEF) (r=0.66, p<0.0001). According to the histo-pathological study of two autopsied hearts, severe myocardial fibrosis was seen in segments with fixed perfusion defect. In addition, the mismatched segments of BMIPP defect score > 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)

Shimoyama, Katsuya [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

1999-10-01

314

I-123 MIGB and Tl-201 myocardial scintigraphies in patients with dilated cardiomyopathy  

International Nuclear Information System (INIS)

123-metaiodobenzylguanidine (MIBG) and 201Tl myocardial scintigraphies were performed in 7 patients with dilated cardiomyopathy and the data obtained by both scintigraphies were compared with the ejection fraction (EF) determined by echocardiography. A myocardial SPECT was obtained at 15 minutes and at 4 hours after the i.v. injection of 111 MBq of 123I-MIBG and 201Tl-Cl. The SPECT data were visually analysed, and partly by quantitative methods. The perfusion defect of 123I-MIBG was larger than that of 201Tl in all 7 patients. The H/B (myocardium/background uptake ratio) of 201Tl and 123I-MIBG delayed imaging was significantly correlated with the EF (201Tl: r=0.949, 123I-MIBG: r=0.860, p123I-MIBG delayed imaging were also significantly correlated with the EF (r=-0.863, r201Tl were not. The WOR (washout rate) was not correlated with the EF in this study. These results suggest that 123I-MIBG myocardial scintigraphy provides useful information about the cardiac damage in patients with dilated cardiomyopathy. (author)

315

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

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

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

2003-01-01

316

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.)

317

Altered myocardial perfusion in patients with angina pectoris or silent ischemia during exercise as assessed by quantitative thallium-201 single-photon emission computed tomography  

International Nuclear Information System (INIS)

chest pain (67% versus 73%, respectively; p = NS), SPECT was superior to stress electrocardiography for detecting silent myocardial ischemia. The majority of patients in this study with CAD who developed ischemia during exercise testing were asymptomatic, although they exhibited an angiographic profile and extent of abnormally perfused myocardium similar to those of patients with symptomatic ischemia

318

Accumulation of radioisotopes with tumor affinity. II. Comparison of the tumor accumulation of 67Ga-citrate and 201Tl-chloride in vitro.  

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Full Text Available The kinetics in tumor cells and various factors affecting the tumor accumulation of 67Ga-citrate and 201Tl-chloride were studied in vitro. 67Ga was taken up gradually by tumor cells and its excretion from the cells decreased with time. 201Tl was taken up rapidly by tumor cells. Its excretion was very rapid, indicating that the two nuclides had entirely different kinetics in tumor cells. The uptake of 201Tl by culture cells correlated with that of 42KCl and was inhibited by Ouabain. 201Tl was hardly taken up by nonviable tumor cells. These facts indicate that active transport involving Na-K ATPase is involved in the tumor accumulation of 201Tl. The uptake of 67Ga and 201Tl by tumor cells was not affected by the administration of anticancer agents. The uptake of 67Ga by tumor cells was dependent upon the concentration of transferrin in the medium, which apparently plays a role as one of the pathways of tumor accumulation of 67Ga.

Muranaka,Akira

1981-04-01

319

Diagnostic accuracy of 201Tl SPECT·MRI in brain diseases and inter-reader variance of diagnostic performance  

International Nuclear Information System (INIS)

Fifteen-four studies of 201Tl brain tumor SPECT were independently interpreted by 9 nuclear medicine physicians with and without reference magnetic resonance images in 2 separate sessions to define an effect of referring images, and inter-observer variations. The physicians were requested to detect foci of abnormal deposits, and to discriminate whether they were malignant or not according to 5-grade scaling of subjective diagnostic confidence. Receiver-operating characteristics (ROC) analysis was performed. Mean sensitivity for presence of lesions (SFP), and sensitivity and specificity for malignancy of 201Tl SPECT were 84, and 53 and 55%, which were changed to 94 and 74 and 55% after referring to the MR images. The SFP was significantly improved (p201Tl brain tumor SPECT has moderate sensitivity and specificity for malignancy, which is not improved by addition of anatomical reference images, that additional MR images reduce inter-observer variation of confidence on lesion presence, and that SPECT localization of lesions has great inter-observer variations. (author)

320

Sensitivity and accuracy of thallium-201 myocardial scintigraphy in the detection of coronary artery and myocardial disease  

International Nuclear Information System (INIS)

169 patients (154 men, 15 women, mean age 49.5 years, range 27 to 64 years) were studied by means of 201-Thallium myocardial scintigraphy (201-Tl) and coronary angiography. According to the coronarangiogram, 130 patients had coronary artery disease (CAD): 53 a 1-vessel CAD, 29 a 2-vessel CAD, 48 a 3-vessel CAD. 39 patients had normal or less than 50% stenosed coronary arteries, but only 13 of these patients had also a normal ventriculogram, whereas 26 had an abnormal ventriculogram with local hypo-, a- or dyskinesia, diffuse hypokinesia, dilatation, or marked hypertrophy. The ramus interventicularis anterior (RIVA) was involved (stenosis of more than 50%) in 117 cases, the ramus circumflexus (R. circ.) in 70 cases, and the right coronary artery (RCA) in 67 cases. 201-Tl was abnormal in 98% of all 130 patients with CAD, in 100% of 93 patients with prior infarction, and in 95% of 37 patients without prior infarction. The sensitivity of the rest and/or exercise ECG in the same patients was only 79%, 88% and 57%, respectively. 201-Tl was abnormal in all 26 patients with a pathologic ventriculogram in spite of normal coronary arteries. 201-Tl and ECG were normal in only 9 of the 13 patients (=69%) with normal coronary arteries and normal ventriculogram. Myocardial biopsy, however, performed in 2 of the other 4 patients disclosed in part severe degenerative changes which can possibly explain the abnormal findings of 201-Tl and ECG. Significantly, i.e. more than 50% stenosedSignificantly, i.e. more than 50% stenosed RIVA was correctly detected by 201-Tl in 98%, R. circ. in 71%, and RCA in 91% of the cases. The specificity of 201-Tl was limited by the great number of patients with a pathologic ventriculogram combined with normal coronary arteries. (orig.)

 
 
 
 
321

Quantitative 201Tl scintigraphy of the lower limbs in peripheral artery disease  

International Nuclear Information System (INIS)

201Tl scintigraphy is useful in evaluating the hemodynamic consequences of arterial stenoses in arterial occlusive disease. The aim of the present study was to determine normal values for absolute Tl uptake in the lower leg, for the quotient between left and right lower leg uptake as well as for the redistribution pattern after bicycle exercise. We examined as reference 49 patients without clinical evidence of peripheral or coronary artery disease: absolute Tl uptake in the lower leg in anterior scintigraphy (acquisition time: 120 sec) was 5.02±1.70 counts/pixel (left) 5.21±1,53 counts/pixel (right), the quotient between right and left lower leg was 0.85±0.09 and the redistribution pattern (quotient of the mean activity exercise/rest) 0.82±0.17 (left) and 0.83±0.15 (right). The arithmetic mean minus 2 standard deviations was regarded as the lower limit of normal. In 8 patients with mechanical compression of the left femoral artery before injection at least two scintigraphic parameters were abnormal, in 7 patients with angiographically proven peripheral artery disease at least one scintigraphic parameter was below normal. Quantification of Tl redistribution offers diagnostic advantages in bilateral peripheral artery disease. (orig.)

322

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

International Nuclear Information System (INIS)

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

323

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)

324

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)

325

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  

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We investigated the impact of intracoronary injection of autologous mononuclear bone marrow cells (BMC) in patients with acute ST elevation myocardial infarction (STEMI) on left ventricular volumes, global and regional systolic function and myocardial perfusion. The study included 39 patients with first anterior STEMI treated successfully with primary percutaneous coronary intervention. They were randomly assigned to the treatment group or the control group in a 2:1 ratio. The patients underwent baseline gated single-photon emission computed tomography (G-SPECT) 3-10 days after STEMI with quantitative and qualitative analysis of left ventricular perfusion and systolic function. On the following day, patients from the BMC treatment group were subjected to bone marrow aspiration, mononuclear BMC isolation and intracoronary injection. No placebo procedure was performed in the control group. G-SPECT was repeated 6 months after STEMI. Baseline and follow-up G-SPECT studies were available for 36 patients. At 6 months in the BMC group we observed a significantly enhanced improvement in the mean extent of the perfusion defect, the left ventricular perfusion score index, the infarct area perfusion score and the infarct area wall motion score index compared to the control group (p=0.01-0.04). However, the changes in left ventricular volume, ejection fraction and the left ventricular wall motion score index as well as the relative changes in the infarct area wall motion score 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

326

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.)

327

Factors affecting accuracy of ventricular volume and ejection fraction measured by gated Tl-201 myocardial perfusion single photon emission computed tomography  

International Nuclear Information System (INIS)

Systemic errors in the gated single photon emission computed tomography (SPECT) measurement of left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) may occur. We evaluated whether patient-related factors affected the accuracy of EDV, ESV, and EF measured by electrocardiogram-gated Tl-201 SPECT. A total of 518 patients without perfusion defects on Tl-201 SPECT or coronary artery disease were studied. EDV, ESV, and EF were measured from echocardiography and adenosine stress/redistribution gated Tl-201 SPECT using commercially available software packages (QGS and 4D-MSPECT). We identified factors affecting the accuracy of gated SPECT via multiple linear regression analysis of the differences between echocardiography and gated SPECT. Gated SPECT analyzed with QGS underestimated EDV and ESV, and overestimated EF, but 4D-MSPECT overestimated all those values (p<0.001). Independent variables that increased the difference in EDV between echocardiography and gated SPECT were decreasing LV end-diastolic wall thickness, decreasing body surface area, female sex and increasing EDV (p< 0.001). Those for ESV were decreasing LV end-systolic wall thickness, female sex, and decreasing ESV (p<0.001). Increasing end-systolic wall thickness, male sex and decreasing age were independent determinants associated with an increased difference in EF (p< 0.001). Adenosine stress SPECT showed significantly higher EDV and ESV values and a lower EF higher EDV and ESV values and a lower EF than did redistribution SPECT (p< 0.001). In determination of EF, QGS demonstrated a smaller bias than did 4D-MSPECT. However, in men with LV hypertrophy, 4D-MSPECT was superior to QGS. Systemic error by gated Tl-201 SPECT is determined by individual patient-characteristics

328

Reverse redistribution on thallium-201 single-photon emission tomography after primary angioplasty: a one-year follow-up study  

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The prognostic significance of reverse redistribution (RR) on thallium-201 single-photon emission tomography (SPET) images after acute myocardial infarction (AMI) has not been studied in detail. Moreover, RR data in patients treated with primary angioplasty are lacking. Fifty consecutive patients (including 40 men with a mean age of 54{+-}11 years) with a first AMI were treated with primary angioplasty and followed up for 13{+-}5 months for the following end-points: death, reinfarction and recurrent angina requiring revascularisation. Admission and peak creatine kinase myocardial enzyme (CKMB) and ejection fraction (EF) at discharge were studied as markers of myocardial damage. Thallium-201 stress-redistribution SPET studies at 1 month were analysed using a 13-segment, 4-point scoring system. Segments showing a worsening of perfusion by at least 1 point on redistribution studies were defined as showing RR. RR was present in 13 (26%) patients (group 1) and absent in 37 (74%) (group 2). Both groups were comparable for age, sex, peak CKMB release, EF and Q-wave myocardial infarctions. TIMI flow 3 was obtained in 92% in group 1 and 95% in group 2 (P = 0.95). On admission, CKMB was significantly lower in group 1 (18{+-}14 vs 44{+-}41 U/l, P = 0.03). Also, segments showing reversible perfusion were significantly more frequent in group 2 (1/169 vs 57/481, P = 0.01). During follow-up, no death occurred and the combined documented endpoint of reinfarction and recurrent angina requiring angioplasty or coronary artery bypass grafting was significantly more frequently reached in group 2 (0/13 vs 10/37, P = 0.046). In conclusion, RR is common (26%) after primary angioplasty for a first AMI and is associated with lesser myocardial damage on admission. Patients with RR rarely have reversible segments on {sup 201}Tl SPET and tend to have a favourable outcome after 1 year of follow-up. (orig.) With 3 figs., 4 tabs., 24 refs.

Sutter, J. de [Department of Cardiology, University Hospital Gent, Gent (Belgium)]|[Division of Nuclear Medicine, University Hospital Gent, Gent (Belgium); Wiele, C. van de; Dierckx, R. [Division of Nuclear Medicine, University Hospital Gent, Gent (Belgium); Gheeraert, P.; Buyzere, M. de; Taeymans, Y. [Department of Cardiology, University Hospital Gent, Gent (Belgium)

1999-06-01

329

Role of exercise tolerance test (ETT) and gated single photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) in predicting severity of ischemia in patients with chest pain.  

Science.gov (United States)

This was an observational study carried out in the department of cardiology. Bangabandhu Shikh Mujib Medical University (BSMMU), Dhaka in collaboration with Institute of Nuclear Medicine (INM), Shabag, Dhaka during the period October 2002-March 2003. A total of 54 patients presenting with Canadian Cardiovascular Society (CCS) class I-II severity of chest pain with mean +/-SD age 49.88 +/- 8.44 yrs and having male to female ratio 5.75:1 were included in the study. The main objective of the study was to predict severity of myocardial ischemia by Exercise Tolerance Test (ETT) determined by Duke Treadmill Score (DTS) and by perfusion pattern observed following Single-Photon Emission Computed Tomography myocardial perfusion imaging (SPECT-MPI). All patients underwent ETT and then SPECT-MPI scan using Tc-99m-tetrofosmin in one-day stress and rest protocol. Coronary angiogram (CAG) was done with in six months of the perfusion study. After performing ETT, patients were categorized by DTS and myocardial perfusion studies were also stratified according to severity of perfusion defect. The formula used to calculate the score was: Exercise time- (5 x ST segment deviation)-(4 X Treadmill angina index). The angiographic findings (significant >50% stenosis) and perfusion defects in MPI were compared with the severity of DTS. There were 31 patients who had CAG proven (>50% luminal diameter narrowing) CAD and 23 patients free of CAD. After ETT patients were categorized by Duke Treadmill Score into high DTS 12 (22.22%) patients, intermediate DTS 20 (37.03%) patients low DTS 22 (40.74%) patients. In high DTS group 91.66% patients had perfusion defect, whereas in intermediate and low risk group it was 60% and 40.9% respectively. In high DTS group 91.66% of patients had angiographicaly proven CAD, 58.33% of them had triple vessel disease (TVD) while in intermediate and low risk groups angiographically proven CAD were 65% and 22.72% of whom TVD only in 15% & 0% respectively. The results of ETT using DTS score were satisfactorily correlated with SPECT-MPI scanning in high DTS subsets of patients only. It is therefore, suggested that patient of high risk DTS do not need for myocardial perfusion imaging study and should undergo CAG for further evaluation. But the intermediate and low risk groups were needed myocardial perfusion imaging study to guide for further evaluation. PMID:16689138

Banerjee, S K; Haque, K M H S S; Sharma, A K; Ahmed, C M; Iqbal, A T M; Nisa, L

2005-04-01

330

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)

331

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

International Nuclear Information System (INIS)

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

332

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)

333

Reevaluation of 201Tl-SPECT for patients with solitary pulmonary nodule. Comparison study with biopsy method and tumor marker measurement  

International Nuclear Information System (INIS)

We compared the differential diagnostic capabilities of 201Tl-SPECT and biopsy methods and serum tumor marker in 125 patients with solitary pulmonary lesions composed of 87 lung cancer and 38 benign lesions. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 201Tl-SPECT were 76%, 95%, 97%, 63%, and 82%, respectively. These parameters are similar in biopsy methods. Although sensitivity improved to be 85% by the combination with tumor marker methods, both specificity and accuracy deteriorated to be 55% and 76%. Using combination method with 201Tl-SPECT and biopsy, sensitivity, NPV and accuracy improved to be 84%, 70% and 85%. Based on its high PPV value, 201Tl-SPECT could be useful when biopsy method could not prove lung cancer or in case whose biopsy is considered to be invasive. Because of the lower NPV value owing to false negative cases in some adenocarcinoma, negative 201Tl-SPECT case should be followed up carefully. (author)

334

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

International Nuclear Information System (INIS)

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

335

Approaches to Single Photon Detection  

CERN Document Server

We present recent results on our development of single photon detectors, including: gated and free-running InGaAs/InP avalanche photodiodes; hybrid detection systems based on sum-frequency generation and Si APDs; and SSPDs (superconducting single photon detectors), for telecom wavelengths; as well as SiPM (Silicon photomultiplier) detectors operating in the visible regime.

Thew, R T; Eraerds, P; Walenta, N; Gautier, J-D; Koller, E; Zhang, J; Gisin, N; Zbinden, H

2008-01-01

336

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

International Nuclear Information System (INIS)

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, thin 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

337

Myocardial gated single photon emission tomography (GSPECT) in men and women with low probability of coronary artery disease - qualitative assessment of beating slices and polar plots  

International Nuclear Information System (INIS)

Assessment of the variability of regional wall motion and thickening in men and women with normal left ventricular contraction and low probability of CAD by GSPECT. The rest 99mTcMyoview GSPECT protocol (700 Mbq) was performed in 28 women and 14 men. Qualitative beating slices - QLGS and polar plots - QGS were analyzed independently by scoring the colour scale (1 - severe impairment, 4 - normal). Then the regional wall motion and thickening in the anterior, lateral, inferior walls, the septum and apex were estimated. In all patients the motion in the inferior wall and septum assessed on polar maps were significantly different than one in QLGS but better in the apex. Regional wall thickening was underestimated in QGS polar plots in the anterior wall, septum, inferior and lateral wall. End diastolic and end systolic volumes were significantly greater in men (90±29, 69±25, p<0.02 and 40±20, 22±12, p<0.002 for EDV and ESV respectively). In the later group all walls except the inferior showed higher QGS thickening score in comparison to men. The motion score in the anterior wall was also significantly bigger (p<0.05). The visual regional motion and thickening assessment on beating slices in gated SPECT seems to be more reliable than polar plots in patients with normal left ventricular contraction and low probability of coronary artery disease. Gated SPECT polar maps show better myocardial thickening in women probably due to the smaller left ventricle size and subsequent partial volume effect. (author)

338

Relationship between lung-to-heart uptake ratio of technetium-99m-tetrofosmin during exercise myocardial single photon emission computed tomographic imaging and the number of diseased coronary arteries in patients with effort angina pectoris without myocardial infarction  

International Nuclear Information System (INIS)

atio with conventional myocardial perfusion imaging improved the sensitivity to detect multivessel disease to 83% and the specificity to 74%. Lung-to-heart uptake ratio measured by exercise myocardial scintigraphy with 99mTc-tetrofosmin can provide clinically useful information to detect multivessel disease in patients with ischemic heart disease. (author)

339

Thallium-201 myocardial perfusion scintigraphy  

International Nuclear Information System (INIS)

Myocardial perfusion scintigraphy has become a clinically important technique for the noninvasive detection and evaluation of both acute and chronic coronary artery disease and employs almost exclusively the tracer thallium-201. This section of chapter 9 is divided into four parts and provides a comprehensive review of 201Tl scintigraphy. In the first part, the radiotracer is described and the physiologic considerations of thallium uptake and redistribution in the myocardium are emphasized. The second part reviews current knowledge with respect to methodology, including imaging systems, computer applications, tomographic techniques, and quantitative analysis. The third part of this section reviews the clinical interpretation of 201Tl myocardial scintigrams. In the fourth and largest part of the section, the clinical applications of thallium imaging in both chronic and acute coronary artery disease are described

340

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

 
 
 
 
341

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

342

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)

343

201-Tl production studies by 203-Tl(p,3n)201-Pb and 202-Hg(p,2n) nuclear reactions  

International Nuclear Information System (INIS)

Thallium 201 has been produced in the Milan university AVF cyclotron by a 203Tl(p,3n)201Pb and 202Hg(p,2n) nuclear reactions. 201Tl/201Pb were separated radiochemically by the preparation of thallium as thallous iodide after complexation of the lead with EDTA. 202Hg and 201Tl were separated by washing the target and holder, to which the radiothallium adheres with 3HCL and adding NaOH. Quality control is by radiochromatography. (U.K.)

344

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)

345

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 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)

346

Iodine-123 phenylpentadecanoic acid and single photon emission computed tomography in identifying left ventricular regional metabolic abnormalities in patients with coronary heart disease: comparison with thallium-201 myocardial tomography  

International Nuclear Information System (INIS)

Iodine-123 phenylpentadecanoic acid (IPPA) is a synthetic long chain fatty acid with myocardial kinetics similar to palmitate. Two hypotheses were tested in this study. The first hypothesis was that IPPA imaging with single photon emission computed tomography (SPECT) is useful in the identification of patients with coronary artery disease. Fourteen normal volunteers (aged 27 +/- 2 years) and 33 patients (aged 54 +/- 11 years) with stable symptomatic coronary artery disease and at least one major coronary artery with luminal diameter narrowing greater than or equal to 70% were studied with symptom-limited maximal exercise testing. The IPPA (6 to 8 mCi) was injected 1 min before the termination of exercise, and tomographic imaging was performed beginning at 9 min and repeated at 40 min after the injection of IPPA. Nine of the normal volunteers and 13 of the patients had a second examination performed at rest on another day. Using the limits of normal as 2 SD from the normal mean values, 27 of the 33 patients with coronary artery disease demonstrated abnormalities in either the initial distribution or the clearance of IPPA, or both. Nineteen of the 33 patients had a maximal variation of activity distribution of greater than or equal to 25% on the 9 min IPPA images. Twenty-two of the 33 patients had a maximal variation in IPPA washout greater than 17% and 17 had a washout rate less than or equal to 2%. There was good agreement between the location of significant coronary artery stenoses and abnormalities in the initial distribution and clearance of IPPA. The second hypothesis tested was that IPPA imaging is as or more sensitive and, therefore, complementary to thallium-201 imaging in the identification of exercise-induced ischemia in patients. Twenty-five of the 33 patients underwent both thallium-201 and IPPA tomographic imaging after symptom-limited maximal exercise testing

347

Iodine-123 phenylpentadecanoic acid and single photon emission computed tomography in identifying left ventricular regional metabolic abnormalities in patients with coronary heart disease: comparison with thallium-201 myocardial tomography  

Energy Technology Data Exchange (ETDEWEB)

Iodine-123 phenylpentadecanoic acid (IPPA) is a synthetic long chain fatty acid with myocardial kinetics similar to palmitate. Two hypotheses were tested in this study. The first hypothesis was that IPPA imaging with single