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Sample records for dipyridamole 201tl myocardial

  1. Dipyridamole 201Tl scintigraphy in the evaluation of prognosis after myocardial infarction

    SciTech Connect

    Okada, R.D.; Glover, D.K.; Leppo, J.A. )

    1991-09-01

    Dipyridamole 201Tl imaging has been proposed as an alternative to exercise ECG testing for the prehospital discharge evaluation of patients recovering from myocardial infarction. The rationale is that many postinfarction patients with exercise-induced ischemia experience later cardiac events, and the sensitivity of predischarge exercise ECG testing in patients with multivessel disease ranges from only 45% to 62%. In addition, several groups of investigators have shown the sensitivity of submaximum exercise 201Tl imaging to be less than ideal. This report summarizes the current status of dipyridamole 201Tl imaging in the period of 1-13 days after myocardial infarction. Although the number of studies performed to date is limited, the following conclusions can be drawn: dipyridamole 201Tl imaging after myocardial infarction was associated with no serious side effects, and those present could be quickly reversed with aminophylline; redistribution with dipyridamole 201Tl images definitely correlates with prognosis after uncomplicated myocardial infarction; dipyridamole 201Tl imaging is definitely useful in patients unable to exercise for a variety of reasons; and future studies are definitely indicated to further define the role of dipyridamole 201Tl imaging for assessing prognosis, especially in those patients undergoing interventional therapy after acute myocardial infarction.

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

    SciTech Connect

    Josephson, M.A.; Brown, B.G.; Hecht, H.S.; Hopkins, J.; Pierce, C.D.; Petersen, R.B.

    1982-06-01

    Two noninvasive tests to detect and localize coronary stenoses were compared in a fully blinded protocol. /sup 201/Tl myocardial perfusion imaging (MPI) following maximal treadmill exercise and pharmacologic coronary vasodilation with intravenous dipyridamole (DP) was performed in 33 patients. /sup 201/Tl 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-/sup 201/Tl 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-/sup 201/Tl MPI provides a useful alternative test for potential coronary disease patients unable to perform maximal exercise.

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

    SciTech Connect

    Leppo, J.; Boucher, C.A.; Okada, R.D.; Newell, J.B.; Strauss, H.W.; Pohost, G.M.

    1982-09-01

    After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial /sup 201/Tl 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 /sup 201/Tl 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.

  4. [Redistribution of 201 Tl after myocardial scintigraphy with dipyridamole: value in the detection of coronary stenosis and ventricular kinetic anomalies].

    PubMed

    Demangeat, J L; Wolff, F

    1985-12-01

    One hundred and eight-four patients suspected of having coronary artery disease underwent coronary and left ventricular angiography and Tl 201 myocardial scintigraphy with dipyridamole including images of redistribution after 3-4 hours. The results of scintigraphy were assessed visually in all cases and by quantitative analysis in 91 patients. Comparison of early (DIP) and late (REDIS) images showed three types of response: 1) no hypofixation on either (10 patients), 2) a constant defect (59 patients), 3) a reversible defect (115 patients, including 21 cases of "paradoxical" redistribution). The value of the redistribution images was assessed in the diagnosis of coronary stenosis and in the evaluation of ventricular wall function in post-stenotic zones. The following results were obtained: Visual analysis of the DIP scintigraphy alone gave 17 false positive and 8 false negative results (sens: 95%, spec: 41%). The false negative results were all observed in patients at high risk. The DIP/REDIS scintigraphy (considered normal if both images were normal) gave 20 false positive but only 1 false negative result (sens: 99%, spec: 32%). In addition, the negative predictivity increased from 60 to 90%. The considerable reduction in the number of false negative results was due to the detection of "paradoxical" redistribution. The finding indicates that late films must be taken systematically even if the early scintigraphy is normal. Quantitative analysis of DIP scintigraphy was less sensitive and more specific than visual analysis (sens: 82.7%, spec: 68.7%; NVP: 46%). The same was observed when the redistribution films were processed (DIP/REDIS): significantly increased sensitivity and negative predictive value at the cost of a lower specificity (sens: 96%, spec: 41%; NPV: 70%). No significant differences were observed between the type of scintigraphic defect (constant or reversible) and the probability of coronary stenosis (positive predictive value 93 and 86% respectively

  5. Dipyridamole thallium-201 myocardial scintigraphy

    SciTech Connect

    Not Available

    1988-09-01

    Thallium-201 (/sup 201/Tl) myocardial scintigraphy is a sensitive technique for detecting coronary artery disease. Standardized exercise testing is the most common method for inducing myocardial stress for /sup 201/Tl imaging. Unfortunately, a significant number of patients are unable to undergo adequate treadmill or bicycle exercise. In these patients, pharmacologic stress with dipyridamole provides a safe, efficacious, and reliable alternative.

  6. Abnormal 201Tl myocardial single photon emission computed tomography in energetic male patients with myocardial bridge.

    PubMed

    Huang, W S; Chang, H D; Yang, S P; Tsao, T P; Cheng, C Y; Cherng, S C

    2002-11-01

    Myocardial bridge is a relatively benign condition where a major coronary artery is bridged by a band of muscle and narrows during systole, particularly during rapid heart rates. Its clinical presentation and electrocardiogram (ECG) changes overlap with that of coronary artery disease. 201Tl myocardial perfusion imaging is thus frequently prescribed for further evaluation. This retrospective study was carried out to determine the 201Tl image patterns in patients with myocardial bridge. A total of 17 male patients (aged from 30 to 63 years) who had a positive exercise ECG and angiographic evidence of myocardial bridge in the mid-third of the left anterior descending coronary artery were recruited. Most of them were robust and received routine physical check-ups. They had no known heart disease or medication that affected cardiac function. The patients' clinical presentations, echocardiograph and exercise ECG findings were analysed. 201Tl single photon emission computed tomography (SPECT) was performed by intravenous injection of 201Tl (111 MBq) immediately following stress (treadmill or dipyridamole induced) and 4 h after stress, using a fixed, right angle camera equipped with a low energy, general purpose collimator. The images were interpreted independently by two experienced nuclear medicine physicians. Nine of the 17 patients had anterior chest pain during exercise. All patients had an abnormal ECG during exercise, including ST-T wave depression in leads II, III and aVF, and v4-6. Except for eight patients revealing reversible perfusion defect (R), 16 of the 17 patients also exhibited a partial reversible perfusion defect (PR) or a significant reverse redistribution (RR) scan pattern in the anterior or inferior walls of the left ventricle. Myocardial bridge should be taken into consideration in energetic male patients who had abnormal exercise ECGs and the corresponding patterns of Tl SPECT abnormalities including R, PR and RR.

  7. Spontaneous changes in /sup 201/Tl myocardial perfusion imaging after myocardial infarction

    SciTech Connect

    Buda, A.J.; Dubbin, J.D.; MacDonald, I.L.; Strauss, H.D.; Orr, S.A.; Meindok, H.

    1982-12-01

    To examine regional myocardial perfusion after myocardial infarction, 26 patients underwent exercise electrocardiographic testing with /sup 201/Tl 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 /sup 201/Tl imaging. The /sup 201/Tl scintigrams were scored by dividing each image, in 3 views, into 5 segments, using a 5-point scoring scheme. The exercise /sup 201/Tl 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 /sup 201/Tl 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 /sup 201/Tl myocardial perfusion was associated with a loss of stress-induced ischemia in 8 patients (30%). These results indicate that spontaneous improvements in /sup 201/Tl myocardial perfusion imaging may occur after myocardial infarction.

  8. Caffeine reduces dipyridamole-induced myocardial ischemia

    SciTech Connect

    Smits, P.; Aengevaeren, W.R.; Corstens, F.H.; Thien, T. )

    1989-10-01

    The mechanism of action of coronary vasodilation after dipyridamole may be based on inhibition of cellular uptake of circulating endogenous adenosine. Since caffeine has been reported to be a competitive antagonist of adenosine we studied the effect of caffeine on the outcome of dipiridamole-{sup 201}Tl cardiac imaging in one patient. During caffeine abstinence dipyridamole induced myocardial ischemia with down-slope ST depressions on the ECG, and reversible perfusion defects on the scintigrams. When the test was repeated 1 wk later on similar conditions, but now shortly after infusion of caffeine (4 mg/kg), the ECG showed nodepressions, and the scintigrams only slight signs of ischemia. We conclude that when caffeine abstinence is not sufficient, the widespread use of coffee and related products may be responsible for false-negative findings in dipyridamole-201Tl cardiac imaging.

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

    SciTech Connect

    Kondo, C.; Hiroe, M.; Nakanishi, T.; Takao, A. )

    1989-09-01

    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.

  10. Value of planar 201Tl imaging in risk stratification of patients recovering from acute myocardial infarction

    SciTech Connect

    Gibson, R.S.; Watson, D.D. )

    1991-09-01

    Although exercise ECG testing has been shown to have important prognostic value after acute myocardial infarction, exercise 201Tl scintigraphy offers several potential advantages, including: (1) increased sensitivity for detecting residual myocardial ischemia; (2) the ability to localize ischemia to a specific area or areas subtended by a specific coronary artery; (3) the ability to identify exercise-induced left ventricular dysfunction, which is manifested by increased lung uptake or transient left ventricular dilation; and (4) more reliable risk stratification of individual patients. The more optimal prognostic efficiency of 201Tl scintigraphy partially results from the fact that the error rate in falsely classifying patients as low risk is significantly smaller with 201Tl scintigraphy than with stress ECG. Because of these substantial advantages, there seems to be adequate rationale for recommending exercise perfusion imaging rather than exercise ECG alone as the preferred method for evaluating mortality and morbidity risks after acute myocardial infarction.

  11. Cold pressor /sup 201/Tl myocardial scintigraphy in the diagnosis of coronary artery disease

    SciTech Connect

    Ahmad, M.; Dubiel, J.P.; Haibach, H.

    1982-12-01

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

  12. Stress/injection protocols for myocardial scintigraphy with 99Tcm-sestamibi compared with 201Tl: implications of early post-stress kinetics.

    PubMed

    Hurwitz, G A; Blais, M; Powe, J E; Champagne, C L

    1996-05-01

    Stress/injection protocols developed for myocardial perfusion imaging with 201Tl may not be optimal for 99Tcm-sestamibi (MIBI), an agent with lower myocardial extraction and higher abdominal uptake; prolongation of exercise after radiotracer injection might improve these relative drawbacks of MIBI. We compared the kinetics of MIBI and 201Tl by acquiring dynamic planar images for 5-7 min after a bolus injection (n = 180 studies) with stress performed by supine bicycle exercise alone, intravenous dipyridamole or combined stress. Routine or prolonged protocols involved continuation of exercise for 1 or 2.5 min respectively after tracer appearance in the heart. Subsequently, the perfusion images obtained were categorized as normal or showing significant defects. Myocardial uptake of MIBI, normalized for injected dose, body weight and camera sensitivity, was only 40% of that for 201Tl; there were no differences based on test mode or scan result for either perfusion tracer. During the second minute after injection, the cavity/myocardial ratios, an index of blood pool activity, were elevated with MIBI by 25% when compared with 201Tl (P < 0.001). During the third minute, cavity activity was again higher with MIBI, but only in those subjects with abnormal scans. The prolonged exercise phase did not prevent progressive accumulation in the abdomen, but did allow cavity levels to decline before termination of exercise. The prolonged protocol may ensure that myocardial uptake of MIBI is completed during peak blood flow, and therefore is recommended for stress with exercise or with dipyridamole and exercise in combination.

  13. The effects of 201Tl myocardial perfusion scintigraphy studies on oxidative damage in patients.

    PubMed

    Cicek, E; Yildiz, M; Delibas, N; Bahçeli, S

    2009-01-01

    The aim of this study was to investigate gamma radiation-induced oxidative damage in erythrocytes after 201Tl myocardial perfusion scintigraphy. Twenty patients (8 women and 12 men) who performed 201Tl myocardial perfusion scintigraphy were included in this study. The blood samples were taken from patients just before, 1 hour after and three hours after injection of the radiopharmaceutical. Malondialdehyde (MDA) and antioxidant enzymes such as glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) levels were measured to evaluate the gamma radiation induced oxidative damage. The enzyme activities of SOD, GPX and CAT were decreased 1 hour after (p = 0.042, p = 0.697 and p = 0.653 respectively) and 3 hours after (p = 0.003, p = 0.573 and p = 0.002 respectively) injection of the radiopharmaceutical. Malondialdehyde levels were increased 1 hour after (p = 0.10) and 3 hours after (p = 0.47) injection of the radiopharmaceutical. In this study, we found that radiation due to 201Tl myocardial perfusion scintigraphy decreased the erythrocyte antioxidant levels and increased MDA levels.

  14. Thrombolysis in acute myocardial infarction using intracoronary streptokinase: assessment by /sup 201/Tl scintigraphy

    SciTech Connect

    Schuler, G.; Schwarz, F.; Hofmann, M.; Mehmel, H.; Manthey, J.; Maeurer, W.; Rauch, B.; Herrmann, H.J.; Kuebler, W.

    1982-09-01

    Twenty-one patients with acute myocardial infarction, admitted to the hospital within 4 hours after the onset of symptoms, were studied by seven-pinhole /sup 201/Tl scintigraphy before and 1 hour and 24 hours after intracoronary fibrinolysis using streptokinase. The size of the /sup 201/Tl 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 /sup 201/Tl 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 /sup 201/Tl perfusion defect in many patients with acute myocardial infarction. 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.

  15. False-negative dipyridamole-thallium-201 myocardial imaging after caffeine infusion

    SciTech Connect

    Smits, P.; Corstens, F.H.; Aengevaeren, W.R.; Wackers, F.J.; Thien, T. )

    1991-08-01

    The vasodilator effect of intravenously administered dipyridamole may be caused by an increase in endogenous plasma adenosine levels. The authors evaluated the effect of caffeine, an adenosine receptor antagonist, on the diagnostic results of dipyridamole-201Tl myocardial imaging in eight patients with coronary artery disease. Caffeine infusion significantly attenuated the dipyridamole-induced fall in blood pressure and the accompanied increase in heart rate. The infusion of dipyridamole alone resulted in chest pain and ST-segment depressions on the electrocardiogram in four patients, whereas none of these problems occurred when the tests were repeated after caffeine. In six of eight patients, caffeine was responsible for false-negative dipyridamole-201Tl tests. Semiquantitive scores of the dipyridamole-induced 201Tl perfusion defects were decreased by caffeine from 9.0 {plus minus} 0.9 to 2.0 {plus minus} 1.1 points (p less than 0.05). Computerized analysis revealed a caffeine-mediated reduction in the percent reversibility of the images from 46% {plus minus} 16% to 6% {plus minus} 10% (p less than 0.05). They conclude that the use of caffeinated products prior to dipyridamole-201Tl testing may be responsible for false-negative findings.

  16. Quantification of myocardial blood flow using (201)Tl SPECT and population-based input function.

    PubMed

    Koshino, Kazuhiro; Fukushima, Kazuhito; Fukumoto, Masaji; Hori, Yuki; Moriguchi, Tetsuaki; Zeniya, Tsutomu; Nishimura, Yoshihiro; Kiso, Keisuke; Iida, Hidehiro

    2014-11-01

    Thallium-201 ((201)Tl) single photon emission computed tomography (SPECT) is an important tool in the diagnosis of ischemic heart disease. Absolute quantification of myocardial blood flow (MBF) has the potential to provide more useful information on myocardial perfusion than semi-quantitative assessments. This study aimed to validate the quantification of MBF using (201)Tl cardiac SPECT based on a population-averaged input function (STD-IF) and one-point blood sample technique. (201)Tl emission and computed tomography (CT)-based attenuation scans were performed on 11 healthy volunteers at rest using a SPECT/CT scanner. Individual input functions (IND-IFs) during the emission scans were based on arterial blood samples. The STD-IF technique was validated as follows: (1) optimal time to calibrate a STD-IF was determined to minimize differences between the calibrated STD-IF and the IND-IFs. (2) Tissue time-activity curves (TTACs) were generated based on a single-tissue compartment model for MBFtrue = 0.5, 1.0, 1.5, and 2.0 mL/min/g, a constant distribution volume of 45 mL/mL, and IND-IFs. The pseudo STD-IF for each subject was generated using the leave-one-out technique. Using the optimal calibration time and the pseudo STD-IFs, MBF values were estimated on the TTACs with an autoradiography method. Optimal mid-scan time (MST) with a fixed duration of 20 min was determined to minimize intersubject variation in estimated MBF errors, and (3) Global and regional MBF values estimated with pseudo STD-IFs were compared to those with IND-IFs using the optimal calibration time and MST. The optimal calibration time and MST were both 20 min after (201)Tl injection. Global MBF determined using both IND-IFs and pseudo STD-IF showed significant correlations with rate-pressure products, R (2) = 0.645; p < 0.01 and R (2) = 0.303; p < 0.05, respectively. The mean percent error in regional MBF using pseudo STD-IFs was 0.69 ± 7.80 % (-12.80 to 14.25 %). No significant

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

    SciTech Connect

    Massie, B.M.; Wisneski, J.; Kramer, B.; Hollenberg, M.; Gertz, E.; Stern, D.

    1982-05-01

    Recently the quantitation of regional /sup 201/Tl clearance has been shown to increase the sensitivity of the scintigraphic detection of coronary disease. Although /sup 201/Tl 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 /sup 201/Tl 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 /sup 201/Tl 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 who do not exercise to an accepted end point.

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

    SciTech Connect

    Pfisterer, M.; Emmenegger, H.; Schmitt, H.E.; Mueller-Brand, J.; Hasse, J.; Graedel, E.; Laver, M.B.; Burckhardt, D.; Burkart, F.

    1982-11-01

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

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

    SciTech Connect

    Gibson, R.S.; Watson, D.D.; Carabello, B.A.; Holt, N.D.; Beller, G.A.

    1982-05-01

    To determine the prevalence and clinical significance of increased lung /sup 201/Tl 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 /sup 201/Tl 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 /sup 201/Tl 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 /sup 201/Tl 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.

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

    SciTech Connect

    Tamaki, S.; Nakajima, H.; Murakami, T.

    1982-11-01

    We evaluated emission computed tomography (ECT) /sup 201/Tl myocardial imaging in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar /sup 201/Tl perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of /sup 201/Tl 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.

  1. A prospective comparison of rubidium-82 PET and thallium-201 SPECT myocardial perfusion imaging utilizing a single dipyridamole stress in the diagnosis of coronary artery disease

    SciTech Connect

    Go, R.T.; Marwick, T.H.; MacIntyre, W.J.; Saha, G.B.; Neumann, D.R.; Underwood, D.A.; Simpfendorfer, C.C. )

    1990-12-01

    The purpose of the present study is to prospectively compare myocardial perfusion imaging with rubidium-82 ({sup 82}Rb) by positron emission tomography (PET) with thallium-201 ({sup 201}Tl) imaging by single-photon emission tomography (SPECT) by recording both studies with a single dipyridamole handgrip stress, and reading both sets of images with the same display technique. In a series of 202 patients with previous coronary arteriography, the sensitivity, specificity, and accuracy of {sup 82}Rb PET were 93%, 78%, and 90% and for {sup 201}Tl SPECT 76%, 80%, and 77%, respectively. When 70 patients with previous therapeutic interventions were excluded, the remaining 132 patients showed a sensitivity, specificity, and accuracy of 95%, 82% and 92% for {sup 82}Rb PET and 79%, 76%, and 78% for {sup 201}Tl SPECT. The improved contrast resolution of PET resulted in markedly superior images and a more confident identification of defects.

  2. Microvascular obstruction on delayed enhancement cardiac magnetic resonance imaging after acute myocardial infarction, compared with myocardial (201)Tl and (123)I-BMIPP dual SPECT findings.

    PubMed

    Mori, Hiroaki; Isobe, Satoshi; Sakai, Shinichi; Yamada, Takashi; Watanabe, Naoki; Miura, Manabu; Uchida, Yasuhiro; Kanashiro, Masaaki; Ichimiya, Satoshi; Okumura, Takahiro; Murohara, Toyoaki

    2015-08-01

    The hypo-enhanced regions within the hyper-enhanced infarct areas detected by cardiac magnetic resonance (CMR) imaging reflect microvascular obstruction (MO) after acute myocardial infarction (AMI). The combined myocardial thallium-201 ((201)Tl)/iodine-123-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid ((123)I-BMIPP) dual single-photon emission computed tomography (SPECT) is a useful tool for detecting myocardial reversibility after AMI. We evaluated whether MO could be an early predictor of irreversible myocardial damage in comparison with (201)Tl and (123)I-BMIPP dual SPECT findings in AMI patients. Sixty-two patients with initial AMI who successfully underwent coronary revascularization were enrolled. MO was defined by CMR imaging. Patients were divided into 2 groups as follows: MO group (n=32) and non-MO group (n=30). Scintigraphic defect scores were calculated using a 17-segment model with a 5-point scoring system. The mismatch score (MMS) was calculated as follows: the total sum of (Σ) (123)I-BMIPP defect score minus Σ(201)Tl defect score. The percentage mismatch score (%MMS) was calculated as follows: MMS/(Σ(123)I-BMIPP score)×100 (%). The percentage infarct size (%IS) was significantly greater in the MO group than in the non-MO group (32.2±13.8% vs. 18.3±12.1%, p<0.001). The %MMS significantly correlated with the %IS and the percentage MO (r=-0.26, p=0.03; r=-0.45, p<0.001, respectively). The %MMS was significantly greater in the non-MO group than in the MO group (45.4±42.4% vs. 13.3±28.0%, p=0.001), and was an independent predictor for MO (OR 0.97, 95%CI 0.94-0.99, p=0.02). Our results reconfirm that, in comparison with myocardial dual scintigraphy, MO is an important structural abnormality. CMR imaging is useful for the early detection of irreversible myocardial damage after AMI. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    Knesaurek, Karin; Machac, Josef

    2000-11-01

    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.

  4. Exercise supplementation of dipyridamole for myocardial perfusion imaging

    SciTech Connect

    DePuey, E.G.

    1991-08-01

    The substitution of intravenous dipyridamole for symptom-limited treadmill exercise has provided a non-invasive means to diagnose coronary artery disease with 201Tl scintigraphy in patients unable to adequately exercise. Limitations of dipyridamole/thallium imaging are primarily due to suboptimal image quality secondary to hepatic tracer concentration and decreased test sensitivity in patients who are dipyridamole non-responders. Low-level treadmill exercise supplementation improves image quality, whereas handgrip has little, if any, benefit. The effect of low-level exercise in augmenting coronary blood flow is unknown and reports regarding the effect of handgrip are conflicting. The diagnostic benefit of these maneuvers in improving test sensitivity and decreasing the number of non-responders has not been documented. The combination of maximal, symptom-limited treadmill exercise and intravenous dipyridamole is a theoretically attractive option to improve overall test sensitivity, but the physiologic consequences and potential side effects should be more thoroughly investigated.

  5. Tomographic thallium-201 myocardial perfusion scintigrams after maximal coronary artery vasodilation with intravenous dipyridamole: comparison of qualitative and quantitative approaches

    SciTech Connect

    Francisco, D.A.; Collins, S.M.; Go, R.T.; Ehrhardt, J.C.; Van Kirk, O.C.; Marcus, M.L.

    1982-08-01

    Eighty-six patients had thallium-201 (/sup 201/Tl) myocardial perfusion scintigrams after intense coronary artery dilation with i.v. dipyridamole. Tomographic and planar /sup 201/Tl scintigrams were obtained in each patient. Tomographic scintigrams were interpreted using quantitative or visual criteria; planar scintigrams were assessed using visual criteria only. When visual criteria were used, interobserver variability was 40% for tomographic scintigrams and 44% for planar scintigrams. In the 24 patients with normal or nonsignificant CAD, quantitative analysis of the tomograms (range approach) indicated that one of 24 (4%) had a positive image (specificity 96%%); in contrast, when visual criteria were used to interpret the tomographic or planar /sup 201/Tl scintigrams, eight of 24 (33%) had positive scintigrams (specificity 67%). In the 51 abnormal patients, the sensitivity of detecting CAD was 46 of 51 (90%) for tomographic scintigrams interpreted quantitatively, 39 of 51 (76%) for tomographic scintigrams interpreted visually and 41 of 51 (80%) for planar scintigrams assessed visually. The tomographic imaging procedure (quantitative interpretation) also demonstrated a high sensitivity (89%) and specificity (100%) in 28 patients (10 normal and 18 CAD), with a clinical diagnosis of unstable angina pectoris. Overall, the predictive accuracy of an abnormal scintigram with quantitative tomographic imaging (98%) was significantly better (p<0.05) than either qualitative planar or pinhole imaging. (JMT)

  6. Validation and evaluation of model-based crosstalk compensation method in simultaneous /sup 99m/Tc stress and /sup 201/Tl rest myocardial perfusion SPECT

    NASA Astrophysics Data System (ADS)

    Song, X.; Frey, E. C.; Wang, W. T.; Du, Y.; Tsui, B. M. W.

    2004-02-01

    Simultaneous acquisition of /sup 99m/Tc stress and /sup 201/Tl rest myocardial perfusion SPECT has several potential advantages, but the image quality is degraded by crosstalk between the Tc and Tl data. We have previously developed a crosstalk model that includes estimates of the downscatter and Pb X-ray for use in crosstalk compensation. In this work, we validated the model by comparing the crosstalk from /sup 99m/Tc to the Tl window calculated using a combination of the SimSET-MCNP Monte Carlo simulation codes. We also evaluated the model-based crosstalk compensation method using both simulated data from the 3-D MCAT phantom and experimental data from a physical phantom with a myocardial defect. In these studies, the Tl distributions were reconstructed from crosstalk contaminated data without crosstalk compensation, with compensation using the model-based crosstalk estimate, and with compensation using the known true crosstalk, and were compared with the Tl distribution reconstructed from uncontaminated Tl data. Results show that the model gave good estimates of both the downscatter photons and Pb X-rays in the simultaneous dual-isotopes myocardial perfusion SPECT. The model-based compensation method provided image quality that was significantly improved as compared to no compensation and was very close to that from the separate acquisition.

  7. Quantification of infarct size by /sup 201/Tl single-photon emission computed tomography during acute myocardial infarction in humans. Comparison with enzymatic estimates

    SciTech Connect

    Mahmarian, J.J.; Pratt, C.M.; Borges-Neto, S.; Cashion, W.R.; Roberts, R.; Verani, M.S.

    1988-10-01

    We prospectively investigated whether /sup 201/Tl single-photon emission computed tomography (SPECT) could accurately diagnose the presence and quantify the extent of acute myocardial infarction when compared with infarct size assessed by plasma MB-creatine kinase activity. Thirty patients with enzymatic evidence of infarction were imaged within 12-36 hours of chest pain (mean, 23.4 hours). No patient had a previous infarction, and none underwent intervention seeking to restore coronary patency. Infarct size was quantified with computer-generated polar maps of the myocardial radioactivity and expressed as a percentage of the total left ventricular volume. To assess left and right ventricular performance, blood-pool gated radionuclide angiography was performed immediately after SPECT. All 30 patients had perfusion defects consistent with myocardial infarction. Scintigraphic and enzymatic estimates of infarct size correlated well for the group as a whole (r = 0.78, p less than 0.001, SEE = 9.1) but especially for those patients with anterior infarction (r = 0.91, p less than 0.001, SEE = 7.9). The poor correlation observed in patients with inferior infarction (r = 0.50, p less than 0.05, SEE = 10.0) was believed to be related to the frequent occurrence of right ventricular involvement because SPECT assessed only left ventricular damage, whereas the enzymatic method estimated the myocardial injury in both ventricles. A quantitative index of right ventricular infarct size, derived from the relation between the scintigraphic and enzymatic estimates, had a strong inverse correlation with right ventricular ejection fraction (r = -0.89, p less than 0.001, SEE = 3.6).

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

    PubMed

    Maeno, M; Ishida, Y; Shimonagata, T; Hayashida, K; Toyama, T; Hirose, Y; Nagata, M; Miyatake, K; Uehara, T; Nishimura, T

    1993-10-01

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

  9. Effect of time and exercise on the clearance rate of (201)Tl in normal and ischemic myocardium.

    PubMed

    Backus, Barbra E; Hezemans, Rachel E L; Verburg, Frederik A; Keijsersa, Ruth G M; Konijnenberg, Mark W; Verzijlbergen, J Fred

    2010-06-01

    Simultaneous dual isotope (SDI) acquisition of (201)Tl rest/(99m)Tc-sestamibi stress-myocardial perfusion single photon emission computed tomography is a desirable new procedure in nuclear cardiology. In this protocol (201)Tl is injected at rest but imaging is performed not earlier than after exercise. Therefore, one must be convinced that throughout exercise (201)Tl remains distributed in an identical pattern as at rest. Before SDI can be applied clinically, (201)Tl rest MPS before and after exercise test needs to be compared for equality. The aim of this study was to assess the effect of time and exercise on the clearance of preinjected (201)Tl in normal and ischemic myocardium. In 122 patients rest (201)Tl and delayed (n =20) or poststress (n= 102) (201)Tl imaging was performed. Quantitative analysis of mean counts-per-pixel was performed for each segment in a 17-segment model. Differences between rest and delayed or poststress (201)Tl MPS were calculated. Patients with a poststress (201)Tl image were divided into normal (N= 66) and ischemic (N= 36) groups. Visual analysis was performed by two independent observers scoring the 17 segments on a scale of 0-4. The overall difference between rest (201)Tl and poststress (201)Tl MPS was - 15.4%. Normal and ischemic patients showed 16.2 and 14.0% (P =0.17) washout, respectively. Visual assessment by two independent observers revealed no regional differences between rest (201)Tl and delayed or poststress (201)Tl MPS. (201)Tl poststress MPS shows significant washout of thallium. This washout is not segmental, but global over the myocardium. No significant differences are found between normal and ischemic myocardium. The poststress (201)Tl MPS is a reliable reflection of rest perfusion. SDI acquisition of (201)Tl rest/(99m)Tc-sestamibi stress-MPS is clinically applicable.

  10. Regional myocardial blood flow in man during dipyridamole coronary vasodilation

    SciTech Connect

    Sorensen, S.G.; Groves, B.M.; Horwitz, L.D.; Chaudhuri, T.K.

    1985-06-01

    Regional myocardial blood flow before and after intravenous dipyridamole (0.56 mg/kg) was measured during cardiac catheterization in 11 patients using the /sup 133/Xe washout technique. Significant increases in heart rate and decreases in systolic blood pressure were observed with dipyridamole infusion. However, double product and cardiac output did not differ before or after drug infusion. Regional myocardial blood flow increased from 67 to 117 ml/100 mg/min in myocardial segments supplied by nonobstructed coronary arteries. In stenotic coronary arteries, flow increased from 57 to 79 ml/100 mg/min with dipyridamole. We conclude that dipyridamole infusion results in flow differences which discriminate stenotic from nonstenotic coronary arteries.

  11. Markers of left ventricular dysfunction induced by exercise, dipyridamole or combined stress on ECG-gated myocardial perfusion scans.

    PubMed

    Hurwitz, G A; O'Donoghue, J P; MacDonald, A C; Laurin, N R; Powe, J E

    1993-04-01

    An index of left ventricular contraction can be extracted from the cavitary time-activity curve of electrocardiographic (ECG)-gated myocardial perfusion scans. To assess the induction of stress-induced myocardial depression, we compared contraction indexes derived from immediate poststress and delayed 201Tl images with indexes of ventricular dilation and lung uptake in the prediction of severe coronary artery disease (defined as two or more 90% stenoses). Stress procedures were performed in 93 patients with symptom-limited supine bicycle exercise alone, and in 227 with intravenous dipyridamole, combined where possible with exercise. The immediate and delayed contraction indexes reflected left ventricular dysfunction on ventriculography (P < 0.0001), but additionally the immediate index was reduced (P < 0.0001) in severe coronary disease. Stress-induced hypokinesis was seen frequently after each of the test modes. The relationship with angiographic findings was better defined for indexes of contraction than for lung uptake or ventricular dilation (P < 0.01). The prediction of severe coronary disease was optimized by combining the poststress contraction index and lung uptake. These data support the use of ECG-gated myocardial scans in evaluating the functional consequences of stress/imaging procedures.

  12. Myocardial infarction after dipyridamole-assisted thallium-201 imaging

    SciTech Connect

    Biddle, P.; Lanspa, T.J.; Mohiuddin, S.M.; Malesker, M.A.; Hilleman, D.E. )

    1989-09-01

    A 77-year-old woman with suspected coronary artery disease underwent an oral dipyridamole/thallium-201 myocardial imaging study. Approximately 75 minutes after ingestion of dipyridamole 300 mg suspension, the patient developed chest pain, hypotension, nausea, and diaphoresis. An electrocardiogram revealed ST-T wave changes suggestive of inferior ischemia. Appropriate therapeutic measures, including aminophylline and nitroglycerin, were instituted. Delayed thallium images revealed reversible ischemia in the anteroseptal and posterobasal regions with a fixed defect in the inferobasal region. Cardiac enzyme studies were also indicative of acute myocardial injury. The patient subsequently underwent coronary arteriography and four-vessel coronary artery bypass grafting and was discharged without further complication. This report raises concerns about the potential danger of dipyridamole in patients with severe coronary artery stenosis and collateral circulation. Prophylactic aminophylline should be considered in these patients.

  13. Dipyridamole combined with exercise for thallium-201 myocardial imaging.

    PubMed Central

    Walker, P R; James, M A; Wilde, R P; Wood, C H; Rees, J R

    1986-01-01

    A new stress test for thallium-201 myocardial imaging in which pharmacological coronary vasodilatation with dipyridamole is combined with dynamic exercise is described. In 38 patients with coronary artery disease the sensitivity, total number of defects, degree of redistribution, and visual quality of thallium-201 imaging were greater after dipyridamole with exercise testing than after exercise alone. When the data from these 38 patients were combined with the results of dipyridamole-exercise imaging in 49 patients in whom exercise electrocardiography had been inconclusive then the technique gave a sensitivity for coronary disease of 87% and a specificity of 92%. Dipyridamole also increased the sensitivity of the exercise electrocardiogram, so that no patient with coronary disease had a strictly negative dipyridamole-exercise stress test. Only five of 214 patients who have now undergone this test have had complications requiring reversal of vasodilatation with aminophylline. The combined use of dipyridamole and exercise in this simple technique is a reliable and safe improvement on standard thallium-201 imaging tests. Images Fig. 1 PMID:3964497

  14. Effect of nifedipine on dipyridamole thallium-201 myocardial scintigraphy

    SciTech Connect

    Bonaduce, D.; Muto, P.; Morgano, G.; Canonico, V.; Breglio, R.; Salvatore, M.; Condorelli, M.

    1986-06-01

    The effect of a calcium antagonist drug, nifedipine, on dipyridamole thallium-201 images was assessed in 10 angina patients with positive dipyridamole test. Two dipyridamole thallium-201 tests were performed, the first in basal conditions, the second after administration of 20 mg nifedipine. After dipyridamole, heart rate and double product increased respectively from 68.0 +/- 8.2 to 94.7 +/- 11.5 beats/min (p less than 0.01) and from 9459.5 +/- 1800.2 to 12,770.0 +/- 1864.7 mmHg X beats/min (p less than 0.01). Dipyridamole when infused after nifedipine induced an increase in heart rate from 74.2 +/- 7.16 to 88.8 +/- 5.6 beats/min (p less than 0.01) and in double product from 9650.5 +/- 1348.0 to 11,399.0 +/- 1146 mmHg X beats/min (p less than 0.05). Systolic and diastolic blood pressures were unmodified during the two studies. Segment scores were comparable before and after nifedipine. Thus, nifedipine does not worsen thallium-201 myocardial images obtained during dipyridamole infusion, therefore, this test could provide an alternative to exercise thallium-201 in patients receiving calcium antagonist drugs.

  15. Use of intravenous dipyridamole in thallium 201 myocardial perfusion imaging

    SciTech Connect

    Zeller, F.P.; Blend, M.J.

    1987-01-01

    Thallium 201 myocardial perfusion imaging is a standard method of evaluating regional myocardial blood flow. Myocardial perfusion is best evaluated at rest and during exercise, however, alternative methods have been sought to increase coronary blood flow in patients incapable of performing adequate exercise. A promising new method is the use of intravenous dipyridamole for pharmacologic stress imaging. It has distinct advantages over traditional treadmill exercise testing. The primary advantage of combining intravenous dipyridamole and thallium 201 is for testing patients in whom exercise is impractical or contraindicated. Examples include patients taking beta blockers and those who have had myocardial infarction or have severe peripheral vascular disease. To date, this agent has been available only to clinical investigators in approved protocols. With continued success, it should be approved for general use in the near future. 33 references.

  16. Myocardial kinetics of thallium-201 after dipyridamole infusion in normal canine myocardium and in myocardium distal to a stenosis.

    PubMed Central

    Okada, R D; Leppo, J A; Boucher, C A; Pohost, G M

    1982-01-01

    The purpose of the present study was to define myocardial and blood thallium-201 (Tl-201) kinetics after infusion of dipyridamole in normal canine myocardium and in myocardium distal to a coronary artery stenosis. Miniature radiation detector probes were implanted in the left ventricle in 39 open-chest dogs. A balloon constrictor was placed around the proximal left circumflex coronary artery. Electromagnetic flow probes were positioned proximally around both the left circumflex and left anterior descending coronary arteries. In five control dogs (group 1) the balloon occluder was not inflated; in 12 dogs (group 2) a mild stenosis was created such that resting flow was not reduced, yet the hyperemic response after 10 s of total occlusion was partially attenuated; in nine dogs (group 3) a moderate stenosis was created such that resting flow was not reduced, yet the hyperemic response was completely eliminated; and in 13 dogs (group 4) a severe stenosis was created such that resting flow was reduced. After intravenous dipyridamole (0.08 mg/kg . min-1 x 4 min), 1.5 mCi Tl-201 was injected intravenously and probe counts were collected continuously for 4 h. The mean 4-h fractional myocardial Tl-201 clearance for nonstenotic zones was 0.35, 0.27 for group 2 stenotic zones, 0.19 for group 3 stenotic zones, and 0.05 for group 4 stenotic zones (P less than 0.0001). After reaching peak activity, myocardial Tl-201 activity cleared biexponentially with a final decay constant lambda 2 = 0.0017 +/- 0.0001 min-1 (SE) for nonstenotic zones, 0.0011 +/- 0.0001 min-1 for group 2 stenotic zones, and 0.0006 +/- 0.0001 min-1 for group 3 stenotic zones (P less than 0.01). Group 4 stenotic zone Tl-201 clearances were negligible (decay constant essentially zero). Blood Tl-201 activity decayed triexponentially with a final blood lambda 3 = 0.0018 +/- 0.0001 min-1, which was almost identical to the final myocardial lambda 2 decay constant. Thus, the rate of myocardial Tl-201 clearance can

  17. High spin spectroscopy of 201Tl

    NASA Astrophysics Data System (ADS)

    Das Gupta, S.; Bhattacharyya, S.; Pai, H.; Mukherjee, G.; Bhattacharya, Soumik; Palit, R.; Shrivastava, A.; Chatterjee, A.; Chanda, S.; Nanal, V.; Pandit, S. K.; Saha, S.; Sethi, J.; Thakur, S.

    2013-10-01

    The high spin structure of 201Tl has been studied by γ-ray spectroscopic method using the 198Pt(7Li,4n)201Tl reaction at 45 MeV beam energy. The level scheme of 201Tl has been considerably extended through the observation of 31 new transitions. Several new band structures have been established. The 9/2- oblate band has been significantly extended beyond the particle alignment frequencies. The band structures and the other excited states have been compared with the neighboring odd-A Tl isotopes and with the even-even core nucleus 200Hg. The total Routhian surface calculations have been performed to study the deformation and shape changes as a function of spin in this nucleus.

  18. Effect of maintenance oral theophylline on dipyridamole-thallium-201 myocardial imaging using SPECT and dipyridamole-induced hemodynamic changes

    SciTech Connect

    Daley, P.J.; Mahn, T.H.; Zielonka, J.S.; Krubsack, A.J.; Akhtar, R.; Bamrah, V.S.

    1988-06-01

    To evaluate the effect of maintenance oral theophylline therapy on the diagnostic efficacy of dipyridamole-thallium-201 single photon emission computed tomography (SPECT) imaging for coronary artery disease, dipyridamole-thallium-201 SPECT imaging was performed in eight men with documented coronary artery disease before initiation of theophylline treatment and repeated while these patients were receiving therapeutic doses of oral theophylline. Before theophylline treatment, intravenous dipyridamole caused a significant increase in heart rate, decrease in blood pressure, angina in seven of eight patients, and ST segment depression in four of eight patients. While they were being treated with theophylline, none of the patients had angina or ST segment depression, and there were no hemodynamic changes with intravenous dipyridamole. Before theophylline treatment, dipyridamole-thallium-201 SPECT imaging showed reversible perfusion defects in myocardial segments supplied by stenotic coronary arteries. With theophylline treatment, dipyridamole-thallium-201 SPECT showed total absence of reversible perfusion defects. Treatment with theophylline markedly reduced the diagnostic accuracy of dipyridamole-thallium-201 imaging for coronary artery disease.

  19. Tomographic myocardial perfusion scintigraphy in children with Kawasaki disease

    SciTech Connect

    Spielmann, R.P.; Nienaber, C.A.; Hausdorf, G.; Montz, R.

    1987-12-01

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

  20. Thallium-201 scintigraphy perfusion defect with dipyridamole in a patient with a myocardial bridge

    SciTech Connect

    Bennett, J.M.; Blomerus, P.

    1988-04-01

    A patient with myocardial bridging and a thallium-201 scintigraphy perfusion defect after the administration of intravenous dipyridamole is presented. The same patient had a normal perfusion study on exercise stress testing. The effects of coronary vasodilators and dipyridamole on coronary artery flow patterns in patients with myocardial bridging are discussed. We suggest that coronary vasodilators may induce perfusion defects in patients with myocardial bridging and should be avoided in such patients.

  1. Photon emission probabilities of 201Tl

    NASA Astrophysics Data System (ADS)

    Kawada, Y.; Hino, Y.; Gatot, W.

    1990-01-01

    Precise measurements of the gamma- and X-ray emission probabilities per decay of 201Tl have been performed using a photon spectrometer with a reverse electrode Ge coaxial detector (LO-AX). The source activity was determined by the 4πβ-γ coincidence technique, and the influence of the coincidence sum effects between the K X-rays and the gamma rays was assessed. Radioactive impurities such as 200Tl and 202Tl were also taken into account.

  2. Thallium-201 myocardial imaging during coronary vasodilation induced by oral dipyridamole

    SciTech Connect

    Gould, K.L.; Sorenson, S.G.; Albro, P.; Caldwell, J.H.; Chaudhuri, T.; Hamilton, G.W.

    1986-01-01

    Myocardial perfusion imaging of /sup 201/TI injected during maximum exercise has been an important diagnostic tool for coronary artery disease. Pharmacologic coronary vasodilation by i.v. infusion of dipyridamole may be used in lieu of exercise stress for purposes of diagnostic perfusion imaging. However, i.v. dipyridamole is not currently available from commercial sources for widespread routine use. Accordingly, this study was carried out in order to determine whether high dose, oral dipyridamole would be useful as a coronary vasodilator for purposes of diagnostic perfusion imaging. Fifty-eight patients undergoing diagnostic coronary arteriography also had myocardial perfusion imaging with 201TI under conditions of rest, maximum exercise stress, and high dose oral dipyridamole. Of those patients who had a defect on exercise thallium images, 75% also had a perfusion defect on thallium images after high dose oral dipyridamole. These results indicate that oral dipyridamole causes sufficient coronary arteriolar vasodilation and increase of coronary flow in nonstenotic arteries to identify perfusion defects comparable to those seen on maximum exercise stress in at least 75% of cases. In 25% of patients with exercise defects, no perfusion defect was seen after oral dipyridamole. Thus, oral dipyridamole is a potent coronary vasodilator, comparable to exercise stress in most cases, but in a minority of patients may not be comparable to exercise stress.

  3. Dipyridamole thallium-201 scintigraphy as a preoperative screening test. A reexamination of its predictive potential. Study of Perioperative Ischemia Research Group

    SciTech Connect

    Mangano, D.T.; London, M.J.; Tubau, J.F.; Browner, W.S.; Hollenberg, M.; Krupski, W.; Layug, E.L.; Massie, B. )

    1991-08-01

    The authors examined the value of dipyridamole thallium-201 (201Tl) scintigraphy as a preoperative screening test for perioperative myocardial ischemia and infarction. They prospectively studied 60 patients undergoing elective vascular surgery. They performed 201Tl scintigraphy preoperatively and blinded all treating physicians to the results. Historical, clinical, laboratory, and physiological data were gathered throughout hospitalization. Myocardial ischemia was assessed during the intraoperative period using continuous 12-lead electrocardiography (ECG) and transesophageal echocardiography (TEE) and during the postoperative period using continuous two-lead ambulatory ECG. Adverse cardiac outcomes (cardiac death, myocardial infarction, unstable angina, severe ischemia, or congestive heart failure) were assessed daily throughout hospitalization. Twenty-two patients (37%) had defects that improved or reversed on delayed scintigrams (redistribution defects), 18 (30%) had persistent defects, and 20 (33%) had no defects on 201Tl scintigraphy. There was no association between redistribution defects and adverse cardiac outcomes: 54% (seven of 13) of adverse outcomes occurred in patients without redistribution defects, and the risk of an adverse outcome was not significantly increased in patients with redistribution defects. Consistent with these findings, there was also no association between redistribution defects and perioperative ischemia: 54% (19 of all 35) of perioperative ECG and TEE ischemic episodes and 58% (14 of 24) of severe ischemic episodes occurred in patients without redistribution defects. The sensitivity of 201Tl scintigraphy for perioperative ischemia and adverse outcomes ranged from 40% to 54%, specificity from 65% to 71%, positive predictive value from 27% to 47% and negative predictive value from 61% to 82%.

  4. Two-dimensional echocardiographic evaluation of ventricular asynergy induced by dipyridamole: correlation with thallium scanning

    SciTech Connect

    Ferrara, N.; Bonaduce, D.; Leosco, D.; Longobardi, G.; Abete, P.; Morgano, G.; Salvatore, M.; Rengo, F.

    1986-09-01

    Myocardial asynergies detected by two-dimensional echocardiography during intravenous administration of Dipyridamole (0.75 mg/kg) were evaluated in 54 patients referred for angiographic evaluation of chest pain. Technically adequate two-dimensional echocardiograms suitable for analysis were recorded in 42 of 54 (77.7%) patients studied. Thallium-201 myocardial perfusion scintigraphy, during dipyridamole test was performed in the same patients. Thirty of the 42 patients studied showed significant coronary narrowing at cardiac catheterization. Dipyridamole-induced wall motion abnormalities and myocardial perfusion defects were detected, respectively, in 19 (63.3%) and 21 (70%) of 30 patients with significant coronary artery disease. Wall by wall comparison of the distribution of dipyridamole-induced echocardiographic asynergy with reversible thallium-201 (/sup 201/Tl) perfusion defects demonstrated complete correlation in 42 segments examined. Three segments with perfusion defects at thallium scanning did not show asynergy during the test while two segments showing wall motion abnormalities during dipyridamole infusion did not manifest perfusion defects. Our study demonstrates that two-dimensional echocardiography during dipyridamole testing is useful in detecting patients with coronary artery disease. Furthermore, ventricular asynergies detected during the test show a high correspondence with site of myocardial perfusion defects at thallium scanning.

  5. Reversibility by dipyridamole of thallium-201 myocardial scan defects in patients with sarcoidosis

    SciTech Connect

    Tellier, P.; Paycha, F.; Antony, I.; Nitenberg, A.; Valeyre, D.; Foult, J.M.; Battesti, J.P.

    1988-08-01

    In order to clarify the significance of anginal pain and myocardial thallium-201 scan defects in cardiac sarcoidosis, the pharmacologic effect of dipyridamole on myocardial perfusion was assessed by planar thallium-201 myocardial scintigraphy in patients with sarcoidosis. Thallium-201 myocardial scintigraphy was performed at rest and after 0.56 mg/kg intravenous dipyridamole during four minutes in 16 patients with sarcoidosis. The myocardial scan (45-degree and 70-degree left anterior oblique, and anterior views) was divided into 15 segments. Results were evaluated by the number of segmental defects and with a global perfusion score (from 0 to 60) by a semi-quantitative index depending on the size and severity of myocardial thallium-201 defects. Thirteen of the 16 patients showed partial or total reversion of their thallium-201 defects on redistribution scanning either at rest or after dipyridamole. The mean (+/- SD) number of myocardial perfusion defects that were present in all the patients decreased from 5.31 +/- 1.78 at rest to 3.25 +/- 2.52 after redistribution (p less than 0.001) and to 2.19 +/- 2.10 after dipyridamole (p less than 0.001). The mean global perfusion score increased from 53.2 +/- 3.0 at rest to 56.2 +/- 2.9 after redistribution (p less than 0.001) and to 57.2 +/- 2.7 after dipyridamole (p less than 0.001). A significant correlation (r = 0.82, p less than 0.001) was found between the increase of global perfusion score on redistribution and after dipyridamole. The reversibility of myocardial scan defects is a common finding in sarcoidosis. It makes unlikely the role of scar fibrosis or extensive confluent granulomas as a mechanism for such defects. The effect of dipyridamole suggests the presence of reversible disorders lying at the coronary microvascular level.

  6. Pharmacodynamic effect of dipyridamole on thallium-201 myocardial perfusion in progressive systemic sclerosis with diffuse scleroderma.

    PubMed Central

    Kahan, A; Devaux, J Y; Amor, B; Menkes, C J; Weber, S; Foult, J M; Venot, A; Guerin, F; Degeorges, M; Roucayrol, J C

    1986-01-01

    We evaluated the effect of dipyridamole on thallium-201 myocardial perfusion in 23 patients with progressive systemic sclerosis (PSS) with diffuse scleroderma. Thallium-201 single photon emission computed tomography (SPECT) was performed at rest and after coronary artery vasodilatation with intravenous dipyridamole (0.14 mg/kg/min for four minutes). The left myocardium was divided into nine segments; each segment was graded as 2.0, 1.5, 1.0, 0.5, 0 (zero represents no activity). Dipyridamole significantly improved resting thallium-201 myocardial perfusion: the mean (SD) number of segments with thallium defects decreased from 6.0 (2.1) at rest to 4.1 (2.5) after dipyridamole (p less than 0.0001); the mean (SD) score in segments with resting defects increased from 0.92 (0.24) at rest to 1.13 (0.38) after dipyridamole (p less than 0.0001); the mean (SD) global score per patient increased from 10.2 (1.8) at rest to 11.4 (2.1) after dipyridamole (p less than 0.02); the global score increased by at least 2.0 in 12 patients and worsened by at least 2.0 in three patients only (p = 0.05). The results of this acute study suggest that some drugs with potent vasodilator activity on small coronary arteries may be beneficial in the treatment of PSS patients with thallium-201 myocardial perfusion abnormalities. Images PMID:3490227

  7. Transient mitral regurgitation: An adjunctive sign of myocardial ischemia during dipyridamole-thallium imaging

    SciTech Connect

    Lette, J.; Gagnon, A.; Lapointe, J.; Cerino, M.

    1989-07-01

    A patient developed transient exacerbation of a mitral insufficiency murmur and a reversible posterior wall perfusion defect during dipyridamole-thallium imaging. Coronary angiography showed significant stenoses of both the right and the circumflex coronary arteries that supply the posterior papillary muscle. Cardiac auscultation for transient mitral incompetence, a sign of reversible papillary muscle dysfunction, is a simple and practical adjunctive test for myocardial ischemia during dipyridamole-thallium imaging. It may confirm that an isolated reversible posterior wall myocardial perfusion defect is truly ischemic in nature as opposed to an artifact resulting from attenuation by the diaphragm.

  8. Thallium-201 myocardial imaging during pharmacologic coronary vasodilation: comparison of oral and intravenous administration of dipyridamole

    SciTech Connect

    Taillefer, R.; Lette, J.; Phaneuf, D.C.; Leveille, J.; Lemire, F.; Essiambre, R.

    1986-07-01

    Although the diagnostic utility of thallium-201 myocardial imaging after dipyridamole infusion is well established, the intravenous form of the drug is not yet commercially available in North America. Fifty patients referred for coronary angiography were prospectively studied. Within a 2 week period, each patient underwent cardiac catheterization and thallium-201 myocardial imaging after both oral and intravenous dipyridamole administration. For the oral protocol, patients were randomly assigned to treatment with either 200 or 400 mg of dipyridamole in tablet form. Coronary artery stenoses of 70% or greater were considered significant. For the 25 patients who received a 200 mg oral dose of dipyridamole, the scintigraphic study showed perfusion defects in 65% of patients with significant coronary artery disease after the oral dose and in 85% of patients after the intravenous dose. For the 25 patients who received a 400 mg oral dose, the sensitivity of the scintigram was 84% after the oral dose and 79% after the intravenous dose. Except for headache and nausea, side effects were less severe and less frequent with oral (either 200 or 400 mg) than with intravenous dipyridamole. Because of the delayed and variable absorption of dipyridamole tablets, the oral studies required a longer period of medical supervision (45 to 60 minutes), and aminophylline was empirically administered after completion of the first set of thallium-201 images. It is concluded from this study that thallium-201 myocardial imaging after coronary vasodilation with a 400 mg oral dose of dipyridamole is a safe, widely available and reliable alternative for the evaluation of coronary artery disease in patients unable to achieve an adequate exercise level on stress testing.

  9. /sup 201/Tl scintigraphy after surgical repair of hemodynamically significant primary coronary artery anomalies

    SciTech Connect

    Rajfer, S.I.; Oetgen, W.J.; Weeks, K.D. Jr.; Kaminski, R.J.; Rocchini, A.P.

    1982-06-01

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

  10. Differential renal uptake of 201Tl: requirements for acquisition, display and quantification.

    PubMed

    Hurwitz, G A; Powe, J E; Mattar, A G; Reid, R H; Driedger, A A; Rendak, I; Hogendoorn, P

    1991-10-01

    Renal uptake of 201Tl may have a role in screening for renal asymmetry in hypertensive patients (HP) who are referred for myocardial scintigraphy. The qualitative aspects of digitized planar images, and quantified differential renal uptake (DRU) of 201Tl were rated by comparing a simple technique (S) for outlining each kidney with an interpolative background subtracted technique (IB). These parameters were assessed in an initial series of patients by varying the length of acquisition (from 1 to 5 min), delay in acquisition (from 10 to 210 min after injection), and image preparation (nine-point smoothing). Six blinded observers rated the quality of coded images. Image quality was improved (P less than 0.01) by increasing the length of acquisition to at least 2 min, by smoothing of the images and by imaging within 2 h of 201Tl injection. Variability in quantification of DRU was suboptimal with acquisition for only 1 min and was more adversely affected with S than with IB. Clinical application of the quantitative technique was assessed in 180 HP and 32 normotensive controls. With IB, the normal range for DRU was slightly greater than for S. The two techniques were comparable in identifying abnormal cases and found 21 +/- 3% (S) and 19 +/- 3% (IB) of HP as lying outside the normal 99% confidence interval. Both quantitative techniques showed excellent agreement with renal angiography (n = 24). Furthermore, preliminary experience with surface markers and with 180 degrees tomography suggests the potential for simultaneous correction for renal depth. These data justify the use of adjunctive renal imaging during myocardial scintigraphy with 201Tl.

  11. Dipyridamole thallium-201 myocardial imaging. Complications associated with oral and intravenous routes of administration

    SciTech Connect

    Aksut, S.V.; Port, S.; Collier, B.D.; Hoffmann, R.G.; Massardo, T.; Hellman, R.S.; Isitman, A.T.; Carnell, A.; Devich, E.C.

    1988-11-01

    Previous reports have shown that TI-201 myocardial imaging with either an oral or intravenous administration of dipyridamole is a suitable diagnostic examination for patients at risk for coronary artery disease who cannot perform treadmill exercise. To compare the incidence of complications associated with these two routes of drug administration, the records of 78 oral and 97 intravenous dipyridamole TI-201 imaging studies were reviewed. The oral administration is associated with a significantly higher incidence of nausea (15% vs. 4%). Despite the higher incidence of nausea, the percentage of patients having one or more dipyridamole-induced symptoms was no greater for the oral (29%) than for the intravenous (37%) administration. Intravenous administration produced both a significantly higher incidence of atypical angina (14% vs. 4%) and a significantly greater increase in heart rate (16.6 vs. 10.2 beats per minute). No patient in either the oral or intravenous dipyridamole protocols had life-threatening arrhythmias or myocardial infarctions. In clinical practice, the difference in complications associated with the oral and intravenous administration of dipyridamole for TI-201 imaging is not significant.

  12. Dipyridamole combined with symptom-limited exercise for myocardial perfusion scintigraphy: image characteristics and clinical role.

    PubMed

    Hurwitz, G A; Powe, J E; Driedger, A A; Finnie, K J; Laurin, N R; MacDonald, A C

    1990-01-01

    Although dipyridamole can be used with myocardial scintigraphy to demonstrate reversible perfusion defects, combining exercise with the pharmacologic tool could improve image quality and information yield. The incidence of perfusion defects and the quality of thallium 201 images were reviewed in a series of 820 patients who had been assigned to a specific stress-test mode. Supine bicycle exercise alone was used (group I) where no pharmacologic or physical factors (e.g., beta-blockers, arthritis) limited performance; otherwise, intravenous dipyridamole was followed by symptom-limited exercise (group II). Angiographic correlation was available in 57 patients in group I, and in 158 in group II; of these, 109 performed significant exercise (greater than or equal to 3 min at increasing workloads) following dipyridamole (group IIA), whereas in 49 (group IIB) the exercise phase following dipyridamole was truncated. All test-mode groups were similar with respect to the incidence of ST segment depression during testing, patient throughput, and the sensitivity of perfusion defects. Chest pain and reversible defects were induced more frequently in group II than in group I. In group IIA, splanchnic background activity was lower (P less than 0.001) than in group IIB, and the false-positive rate tended to be lower. Thus, combining exercise with dipyridamole in patients with non-cardiac limitations to exercise enabled the achievement of optimal results for perfusion scintigraphy.

  13. Acute myocardial infarction associated with intravenous dipyridamole for rubidium-82 PET imaging

    SciTech Connect

    Marwick, T.H.; Hollman, J. )

    1990-03-01

    This report describes the occurrence of chest pain and electrocardiographic features of acute myocardial infarction following intravenous dipyridamole-handgrip stress. Myocardial perfusion imaging (Rb-82 PET) demonstrated a stress-induced perfusion defect. Following failure to respond to medical therapy, urgent cardiac catheterization demonstrated total occlusion of the left anterior descending coronary artery. The vessel was revascularized, with limitation of myocardial damage evidenced by failure to develop anterior Q waves and only modest elevation of cardiac enzyme levels. Complications of intravenous dipyridamole stress are rare, this case constituting the first major problem in over 500 such procedures at this institution. However, this experience demonstrates the importance of vigilant observation during the performance of this technique.

  14. Serial thallium-201 imaging after dipyridamole for coronary disease detection: quantitative analysis using myocardial clearance

    SciTech Connect

    Okada, R.D.; Dai, Y.H.; Boucher, C.A.; Pohost, G.M.

    1984-03-01

    After dipyridamole, canine studies have demonstrated a slower rate of myocardial thallium-201 clearance from zones distal to a coronary artery stenosis compared to normal zones. To determine if criteria based on canine myocardial thallium-201 clearance rates could be applied clinically, 40 patients with and 26 patients without coronary artery disease (CAD) had serial thallium-201 images obtained for 2 to 5 hours after dipyridamole. Regions of interest were manually placed over six left ventricular segments in two projections for each of three imaging times. The myocardial thallium-201 clearance rate was calculated for each of the six segments and, using the clearance rate criterion found in canine studies, was considered abnormal if less than 6.5%/hr. Using this criterion alone, 22 of 26 patients (85%) without CAD had normal and 30 of 40 patients (75%) with CAD had abnormal myocardial thallium-201 clearance rates. A quantitative analysis of regional inhomogeneity in tracer distribution (normal was greater than or equal to 25% difference between segments) was negative in 24 of 26 patients (92%) without CAD and positive in 20 of 40 patients (50%) with CAD. When both clearance rate and regional inhomogeneity were considered, 21 of 26 patients (81%) without CAD had negative and 36 of 40 patients (90%) with CAD had positive results. Thus, post-dipyridamole myocardial clearance rate criteria derived from canine studies can be applied to clinical thallium imaging. Quantitative analysis of serial thallium-201 images after dipyridamole is optimized by using myocardial thallium-201 clearance rates. Such an approach is independent of regional inhomogeneities in tracer distribution.

  15. Cost-minimization analysis of intravenous adenosine and dipyridamole in thallous chloride TI 201 SPECT myocardial perfusion imaging.

    PubMed

    Hilleman, D E; Lucas, B D; Mohiuddin, S M; Holmberg, M J

    1997-09-01

    To conduct a cost-minimization analysis of intravenous adenosine and intravenous dipyridamole in thallous chloride TI 201 single-photon emission computed tomography (SPECT) myocardial perfusion imaging. A retrospective, open-label, cost-minimization analysis. University hospital, outpatient nuclear medicine department. Eighty-three patients undergoing dipyridamole TI 201 SPECT and 166 patients undergoing adenosine TI 201 SPECT. A cost-minimization analysis was conducted using a direct cost accounting approach estimating institutional costs. For the purpose of this study, sensitivity and specificity between adenosine SPECT and dipyridamole SPECT were assumed to be identical. Key costs evaluated included acquisition, administration, monitoring, treatment of adverse effects, follow-up care, and repeat tests. Adenosine increased heart rate and lowered blood pressure to a significantly greater extent than dipyridamole. The frequency of adverse reactions was not significantly different (p = 0.103) between adenosine (1.64 +/- 1.32 per patient) and dipyridamole (1.36 +/- 1.23 per patient). The frequency of prolonged and late-onset adverse effects was significantly greater for dipyridamole than for adenosine (p < 0.001). The frequency of adverse events requiring medical intervention was statistically greater for dipyridamole (24%) compared with adenosine (5%) (p < 0.00001). Total cost was significantly less for adenosine ($378.50 +/- $128.20 per patient) compared with dipyridamole ($485.60 +/- $230.40). Although adenosine had a significantly greater acquisition cost than dipyridamole (p < 0.0001), administration, monitoring, and adverse reaction costs were significantly less for adenosine than for dipyridamole. The cost of using dipyridamole is significantly greater than the cost of using adenosine despite adenosine's high acquisition cost. Adenosine is less expensive to use because of lower administration costs, monitoring costs, and adverse effect costs. Adenosine should

  16. Comparison of dipyridamole-echocardiography with dipyridamole-thallium scintigraphy for the diagnosis of myocardial ischemia

    SciTech Connect

    Perin, E.C.; Moore, W.; Blume, M.; Hernandez, G.; Dhekne, R.; DeCastro, C.M. )

    1991-06-01

    After an intravenous infusion of dipyridamole (0.56 mg/kg), the authors performed both echocardiography and thallium scintigraphy in 63 patients who were referred for known or suspected coronary artery disease. Of those patients, 25 returned for coronary arteriography within 1 month after the tests, thus forming the study group for this report. Sensitivity for detection of coronary artery disease, when analyzed region-by-region, was 80% for thallium scintigraphy and 57% for echocardiography, whereas specificity was 85% and 98%, respectively. When evaluating individual patients for the presence or absence of ischemia, they found a sensitivity of 95% for scintigraphy and 58% for echocardiography; corresponding specificities were 50% and 100%. By using arteriography as the gold standard for comparison, it appears that thallium scintigraphy has a significantly higher sensitivity but lower specificity for the detection of coronary artery disease than does echocardiography. Echocardiography may, however, be a useful adjunct to thallium scintigraphy in the evaluation of patients with coronary artery disease.

  17. Myocardial uptake and clearance of thallium-201 in normal subjects: comparison of dipyridamole-induced hyperemia with exercise stress

    SciTech Connect

    Ruddy, T.D.; Gill, J.B.; Finkelstein, D.M.; Strauss, H.W.; McKusick, K.A.; Okada, R.D.; Boucher, C.A.

    1987-09-01

    Thallium-201 uptake and clearance after dipyridamole infusion may differ from that after exercise stress because the hemodynamic effects of these two interventions are different. In this study of normal volunteers, thallium kinetics after dipyridamole (n = 13) were determined from three serial image sets (early, intermediate and delayed) and from serial blood samples and compared with thallium kinetics after exercise (n = 15). Absolute myocardial thallium uptake was greater after dipyridamole compared with exercise (p less than 0.0001), although the relative myocardial distribution was similar. The myocardial clearance (%/h) of thallium was slower after dipyridamole than it was after exercise. Comparing dipyridamole and exercise, the differences in clearance were large from the early to the intermediate image (anterior, -11 +/- 17 versus 24 +/- 5, p = 0.0005; 50 degrees left anterior oblique, -7 +/- 11 versus 15 +/- 8, p = 0.004; 70 degrees left anterior oblique, 3 +/- 9 versus 21 +/- 6, p = 0.001). In contrast, the differences in clearance were small from the intermediate to the delayed image (anterior, 15 +/- 4 versus 20 +/- 2, p = 0.025; 50 degrees left anterior oblique, 15 +/- 4 versus 19 +/- 3, p = 0.13; 70 degrees left anterior oblique, 15 +/- 3 versus 18 +/- 2, p = 0.047). Thallium uptake and clearance in the liver, splanchnic region and spleen were greater after dipyridamole (p less than 0.001). Blood thallium levels were greater after dipyridamole (p less than 0.05) and cleared more slowly (p = 0.07). Thus, myocardial thallium-201 uptake and clearance after dipyridamole infusion differ from thallium kinetics after exercise. This difference is, in part, related to associated differences in extracardiac and blood kinetics. Diagnostic criteria for the detection of abnormal thallium-201 clearance must be specific for the type of intervention.

  18. Pentoxifylline (Trental) does not inhibit dipyridamole-induced coronary hyperemia: Implications for dipyridamole-thallium-201 myocardial imaging

    SciTech Connect

    Brown, K.A.; Slinker, B.K. )

    1990-06-01

    Dipyridamole-thallium-201 imaging is often performed in patients unable to exercise because of peripheral vascular disease. Many of these patients are taking pentoxifylline (Trental), a methylxanthine derivative which may improve intermittent claudication. Whether pentoxifylline inhibits dipyridamole-induced coronary hyperemia like other methylxanthines such as theophylline and should be stopped prior to dipyridamole-thallium-201 imaging is unknown. Therefore, we studied the hyperemic response to dipyridamole in seven open-chest anesthetized dogs after pretreatment with either pentoxifylline (0, 7.5, or 15 mg/kg i.v.) or theophylline (3 mg/kg i.v.). Baseline circumflex coronary blood flows did not differ significantly among treatment groups. Dipyridamole significantly increased coronary blood flow before and after 7.5 or 15 mm/kg i.v. pentoxifylline (p less than 0.002). Neither dose of pentoxifylline significantly decreased the dipyridamole-induced hyperemia, while peak coronary blood flow was significantly lower after theophylline (p less than 0.01). We conclude that pentoxyifylline does not inhibit dipyridamole-induced coronary hyperemia even at high doses.

  19. Cardiac imaging and myocardial kinetics of technetium-tertiary butyl-isonitrile during dipyridamole-induced hyperemia

    SciTech Connect

    Okada, R.D.; Williams, S.J.; Glover, D.K.; Dragatokis, D.

    1988-10-01

    To determine the myocardial kinetics of technetium-tertiary-butyl-isonitrile (Tc-TBI) during dipyridamole-induced hyperemia, the circumflex coronary arteries (LCX) of 15 dogs were partially occluded. Dipyridamole was then infused intravenously over 4 minutes, creating hyperemic flows in the anterior descending (LAD) coronary system. Tc-TBI was administered, then LAD and LCX regional myocardial Tc-TBI activities were continuously monitored with miniature detectors and gamma camera imaging over 3 hours. Microsphere-determined regional myocardial blood flows demonstrated an LCX/LAD flow ratio of 0.81 +/- 0.21 at rest and 0.45 +/- 0.24 (SD) during dipyridamole infusion. Three-hour fractional Tc-TBI clearance rates were minimal and were equal in the LAD (0.14 +/- 0.11) and LCX (0.13 +/- 0.12) zones (p = ns). Excellent gamma camera images, demonstrating the LCX defect, were obtained in all dogs. The correlation coefficient was 0.98 for regional myocardial blood flow vs initial Tc-TBI distribution. In conclusion: (1) Dipyridamole vasodilation unmasked coronary stenoses despite no flow disparities at rest. (2) The initial distribution of Tc-TBI is proportional to regional myocardial blood flow. (3) There is minimal washout and no redistribution into the initial defect over time, and thus image quality is stable over time. (4) Tc-TBI myocardial kinetics may be applicable to closely related agents currently being developed.

  20. Prognostic value of intravenous dipyridamole thallium scintigraphy after an acute myocardial ischemic event

    SciTech Connect

    Younis, L.T.; Byers, S.; Shaw, L.; Barth, G.; Goodgold, H.; Chaitman, B.R.

    1989-07-15

    Seventy-seven patients recovering from an acute coronary event were studied by intravenous dipyridamole thallium scintigraphy to evaluate the prognostic value and safety of the test in this patient subset. Forty-four patients (58%) had unstable angina and 33 (42%) had an acute myocardial infarction. One death occurred within 24 hours of testing. Sixty-eight patients were followed for an average of 12 months; 25, 31 and 23% had a fixed, reversible or combined thallium defect on their predischarge thallium scan. During follow-up, 10 patients died or had a nonfatal myocardial infarction; in each case, a reversible or combined myocardial thallium defect was present. Univariate analysis of 17 clinical, scintigraphic and angiographic variables showed that a reversible thallium defect and the angiographically determined extent of coronary artery disease were predictors of future cardiac events. The extent of coronary disease and global left ventricular ejection fraction were predictors of subsequent reinfarction or death. Logistic regression analyses revealed that a reversible thallium defect (p less than 0.001) and the extent of coronary disease (p less than 0.009) were the only significant predictors of a cardiac event. When death or reinfarction were the outcome variables, the extent of coronary disease (p less than 0.02) and left ventricular ejection fraction (p less than 0.06) were the only variables selected. Thus, intravenous dipyridamole thallium scintigraphy after an acute coronary ischemic syndrome is a useful and relatively safe noninvasive test to predict subsequent cardiac events.

  1. Relationship between gated myocardial perfusion SPECT findings and hemodynamic, electrocardiographic, and heart rate changes after Dipyridamole infusion.

    PubMed

    Gholoobi, Arash; Ayati, Narjess; Baghyari, Alireza; Mouhebati, Mohsen; Atar, Baharak; Dabbagh Kakhki, Vahid Reza

    2017-02-01

    After dipyridamole infusion, electrocardiographic (ECG), blood pressure and heart rate (HR) changes were seen. We tried to investigate whether there is a relationship between hemodynamic, ECG and HR changes after dipyridamole infusion and gated myocardial perfusion SPECT findings. We studied 206 consecutive patients which underwent a 2-day protocol Dipyridamole Stress/Rest Tc99m-Sestamibi gated myocardial perfusion SPECT. Systolic blood pressure (SBP), diastolic blood pressure (DBP), HR and ECG were recorded. HR was mildly increased while SBP and DBP were mildly decreased after Dipyridamole infusion. There was only statistically significant difference between ECG changes as well as transient ischemic dilation (TID) ratio between normal scans and scans with ischemia (P = 0.02 and P = 0.01 respectively). There was correlation between these variables and summed stress score (SSS) and summed difference score (SDS). Patients with ischemia in their scans, 44.3% had ST depression after Dipyridamole infusion. Also ST depression most frequently was seen in patients with left anterior descending artery disease. From patients with abnormal scan + ST depression after Dipyridamole infusion (33 patient), 27 patient (81.81%) had ischemia. There was an association between TID ratio as well as ECG changes after Dipyridamole infusion and SSS, SDS and coronary artery territory abnormality. Difference between calculated left ventricular ejection fraction using stress and rest images had significant correlation with SSS and SDS. ST depression after Dipyridamole infusion and TID ratio had association with ischemia, SSS and SDS. So in equivocal Gated SPECT findings, they could be very useful for interpretation.

  2. Effect of chronic sustained-release dipyridamole on myocardial blood flow and left ventricular function in patients with ischemic cardiomyopathy.

    PubMed

    Akhtar, Mateen; Ordovas, Karen; Martin, Alastair; Higgins, Charles B; Michaels, Andrew D

    2007-01-01

    Dipyridamole increases adenosine levels and augments coronary collateralization in patients with coronary ischemia. This pilot study tested whether a 6-month course of sustained-release dipyridamole/aspirin improves coronary flow reserve and left ventricular systolic function in patients with ischemic cardiomyopathy. Six outpatients with coronary artery disease and left ventricular ejection fraction (LVEF) <40% were treated with sustained-release dipyridamole 200 mg/aspirin 25 mg twice daily for 6 months. Myocardial function and perfusion, including coronary sinus flow at rest and during intravenous dipyridamole-induced hyperemia, were measured using velocity-encoded cine magnetic resonance stress perfusion studies at baseline, 3 months, and 6 months. There was no change in heart failure or angina class at 6 months. LVEF increased by 39%+/-64% (31.0%+/-13.3% at baseline vs 38.3%+/-10.7% at 6 months; P=.01), hyperemic coronary sinus flow increased more than 2-fold (219.6+/-121.3 mL/min vs 509.4+/-349.3 mL/min; P=.01), and stress-induced relative myocardial perfusion increased by 35%+/-13% (9.4%+/-3.4% vs 13.9%+/-8.5%; P=.004). Sustained-release dipyridamole improved hyperemic myocardial blood flow and left ventricular systolic function in patients with ischemic cardiomyopathy.

  3. Effect of coronary blood flow on uptake and washout of /sup 99m/Tc DMPE and /sup 201/Tl

    SciTech Connect

    Nishiyama, H.; Adolph, R.J.; Deutsch, E.

    1982-12-01

    After intravenous administration of /sup 99m/Tc DMPE the flow-dependent kinetics were studied in dogs during induced ischemia and during induced maximal reactive hyperemia. A control group was also studied. Mean time-activity curves obtained from the myocardial wall were compared within the same intervention group and also with other groups. During reactive hyperemia, there was a rapid and absolute increase in uptake followed by a rapid washout, whereas during ischemia there was a slow and decreased uptake followed by a slow washout. The magnitude of /sup 99m/Tc DMPE uptake during reactive hyperemia was slightly less than that of /sup 201/Tl, but the decreased uptake with ischemia was about equal for the two agents. Following maximal uptake in the myocardium the effective half-life of /sup 99m/Tc DMPE was one-third to one-fourth that of /sup 201/Tl. The similar kinetics of /sup 99m/Tc DMPE compared to /sup 201/Tl suggests its usefulness in the evaluation of ischemic heart disease.

  4. Prognostic importance of silent myocardial ischemia detected by intravenous dipyridamole thallium myocardial imaging in asymptomatic patients with coronary artery disease

    SciTech Connect

    Younis, L.T.; Byers, S.; Shaw, L.; Barth, G.; Goodgold, H.; Chaitman, B.R. )

    1989-12-01

    One hundred seven asymptomatic patients who underwent intravenous dipyridamole thallium imaging were evaluated to determine prognostic indicators of subsequent cardiac events over an average follow-up period of 14 +/- 10 months. Univariate analysis of 18 clinical, scintigraphic and angiographic variables revealed that a reversible thallium defect, a combined fixed and reversible thallium defect, number of segmental thallium defects and extent of coronary artery disease were significant predictors of subsequent cardiac events. Of the 13 patients who died or had a nonfatal infarction, 12 had a reversible thallium defect. Stepwise logistic regression analysis selected a reversible thallium defect as the only significant predictor of cardiac events. When death or myocardial infarction was the outcome variable, a combined fixed and reversible thallium defect was the only predictor of outcome. In patients without previous myocardial infarction, the cardiac event rate was significantly greater in those with an abnormal versus normal thallium scan (55% versus 12%, p less than 0.001). Thus, intravenous dipyridamole thallium scintigraphy is a useful noninvasive test to risk stratify asymptomatic patients with coronary artery disease. A reversible thallium defect most likely indicates silent myocardial ischemia in a sizable fraction of patients in this clinical subset and is associated with an unfavorable prognosis.

  5. Giant dipole resonance in 201Tl at low temperature

    NASA Astrophysics Data System (ADS)

    Dang, N. Dinh; Hung, N. Quang

    2012-10-01

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

  6. Assessment by dipyridamole-thallium-201 myocardial scintigraphy of coronary risk before peripheral vascular surgery

    SciTech Connect

    Sachs, R.N.; Tellier, P.; Larmignat, P.; Azorin, J.; Fischbein, L.; Beaudet, B.; Cadilhac, P.; Cupa, M.; De Saint Florent, G.; Vulpillat, M.

    1988-05-01

    From October 1983 to January 1985, 46 patients (38 men and 8 women; average age, 60 years; range, 37 to 83 years) underwent peripheral vascular surgery of either the internal carotid artery or the arteries of the lower limbs. Each patient had a thorough clinical examination, an ECG, and a dipyridamole-thallium-201 myocardial scan before operation. On the basis of results, they were divided into two groups: 20 patients with and 26 patients without chronic ischemic heart disease. Three major cardiac events were noted during or after a period of 1 month after surgery: There were two deaths due to cardiac ischemic events and one patient had postoperative unstable angina pectoris. These three patients were classified in the coronary group (NS). When the patients were classified on the basis of whether or not there was thallium redistribution on serial images after infusion of dipyridamole, 14 with redistribution and 32 without redistribution were noted. The three patients who had major cardiac events were in the former group (p less than 0.04). Our data suggest that patients in whom redistribution occurs have a high incidence of postoperative ischemic events. These patients should be considered for particular preoperative coronary care to avoid major postoperative cardiac events and to increase chances of survival.

  7. Dipyridamole stress and rest transmural myocardial perfusion ratio evaluation by 64 detector-row computed tomography.

    PubMed

    Cury, Roberto C; Magalhães, Tiago A; Paladino, Antonio T; Shiozaki, Afonso A; Perini, Marcela; Senra, Tiago; Lemos, Pedro A; Cury, Ricardo C; Rochitte, Carlos E

    2011-01-01

    Myocardial stress CT perfusion (CTP) can detect myocardial ischemia. We evaluated the transmural perfusion ratio (TPR) of dipyridamole stress CTP to detect significant coronary stenosis (>70%) defined by quantitative invasive coronary angiography (ICA). Twenty-six patients (61.6 ± 8.0 years old; 14 males), without prior myocardial infarction, with positive single-photon emission computed tomography (SPECT; <2 months) and clinical indication for ICA, underwent a customized multidetector-row CT (MDCT) protocol with rest/stress myocardial perfusion evaluation and coronary CT angiography. TPR was defined as mean subendocardial divided by mean subepicardial attenuation and quantified on rest and stress MDCT images. Abnormal TPR was defined as 2 SDs below the mean rest TPR. All 26 patients completed the CT protocol with no adverse events. Rest TPR was measured in all patients with a mean of 1.06 ± 0.11, and abnormal TPR was considered <0.85. For 6 patients with normal coronary arteries by ICA, the mean TPR of territories with a previous positive perfusion defect in SPECT was 1.02 ± 0.18 (95% CI, 0.86-1.18; n = 6), and mean TPR of territories without perfusion defect in SPECT was 1.03 ± 0.09 (95% CI, -0.95 to 1.11; n = 12; P = 0.83). Mean stress TPR in territories with positive SPECT and significant coronary artery disease by quantitative ICA was 0.71 ± 0.13 (95% CI, -0.64 to 0.77) and in the remote myocardial was 1.01 ± 0.09 (95% CI, -0.96 to 1.06; P < 0001). In these territories, a significant Pearson's correlation was observed (r = -0.74, P < 0.001). TPR has a good correlation with SPECT and ICA to detect significant coronary stenosis. Copyright © 2011 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  8. Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block

    PubMed Central

    Cabeda, Estêvan Vieira; Falcão, Andréa Maria Gomes; Soares Jr., José; Rochitte, Carlos Eduardo; Nomura, César Higa; Ávila, Luiz Francisco Rodrigues; Parga, José Rodrigues

    2015-01-01

    Background Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). Objective To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Methods Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution’s ethics committee. Results The patients’ mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). Conclusion The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB. PMID:26421532

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

    SciTech Connect

    Jain, A.; Suarez, J.; Mahmarian, J.J.; Zoghbi, W.A.; Quinones, M.A.; Verani, M.S. )

    1990-10-01

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

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

    SciTech Connect

    Brown, K.A.; Boucher, C.A.; Okada, R.D.; Strauss, H.W.; McKusick, K.A.; Pohost, G.M.

    1982-12-01

    The relation of the appearance of the right ventricle on serium /sup 201/Tl myocardial imaging to coronary artery anatomy was examined in 88 consecutive patients undergoing exercise /sup 201/Tl 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.

  11. Silent myocardial ischemia and infarction in diabetics with peripheral vascular disease: Assessment by dipyridamole thallium-201 scintigraphy

    SciTech Connect

    Nesto, R.W.; Watson, F.S.; Kowalchuk, G.J.; Zarich, S.W.; Hill, T.; Lewis, S.M.; Lane, S.E. )

    1990-11-01

    We investigated the incidence of silent myocardial ischemia and infarction as assessed by dipyridamole thallium scintigraphy in 30 diabetic patients with peripheral vascular disease and without clinical suspicion of coronary artery disease. Seventeen patients (57%) had thallium abnormalities, with reversible thallium defects compatible with ischemia in 14 patients (47%) and evidence of prior, clinically silent myocardial infarction in 11 patients (37%). Thallium abnormalities were most frequent in patients with concomitant hypertension and cigarette smoking (p = 0.001). These results suggest that unsuspected coronary artery disease is common in this particular group of patients with diabetes mellitus.

  12. Preoperative cardiac evaluation by dipyridamole thallium-201 myocardial perfusion scan provides no benefit in patients with abdominal aortic aneurysm.

    PubMed

    Shin, Sung; Kwon, Tae-Won; Cho, Yong-Pil; Lee, Jong-Young; Park, Hojong; Han, Youngjin

    2013-12-01

    The purpose of the present study was to evaluate the benefits of a preoperative dipyridamole thallium-201 myocardial perfusion scan in patients undergoing abdominal aortic aneurysm (AAA) repair. We retrospectively reviewed findings in a prospectively collected database of patients undergoing open or endovascular repair of AAA at the Asan Medical Center, Seoul, Korea, from January 2001 to May 2011. Of 373 patients, 11 (2.9 %) had postoperative myocardial infarction (MI), whereas 24 (6.4 %), 17 (4.6 %), 24 (6.4 %), and 8 (2.1 %) were diagnosed with myocardial ischemia, atrial fibrillation, ventricular arrhythmia, and congestive heart failure, respectively. The incidence of 30-day cardiac-related mortality was 1.6 % (6 of 373 patients). The preoperative variables significantly associated with postoperative cardiac events in multivariate analysis were preoperative congestive heart failure (odds ratio [OR] 8.8, 95 % confidence interval [CI] 1.36-56.73, p = 0.022), long-acting nitrates (OR 8.1, 95 % CI 1.22-54.26, p = 0.03), and body mass index (BMI) higher than 26 (OR 3.6, 95 % CI 1.49-8.48, p = 0.004). The variables obtained from dipyridamole thallium-201 myocardial perfusion scan were not correlates of postoperative cardiac events. The sensitivity of reversible defects for postoperative cardiac events was 14 % and the specificity was 90 %. Subgroup analyses revealed that thallium defects were not significant variables in predicting postoperative cardiac events in patients with coronary artery disease (CAD) or in no-CAD patients. Preoperative dipyridamole thallium-201 myocardial perfusion scans were ineffective in predicting postoperative cardiac complications in AAA patients. These results suggest that the routine use of these tests for preoperative screening of patients undergoing AAA repair may not be warranted.

  13. Dipyridamole thallium imaging

    SciTech Connect

    Beer, S.G.; Heo, J.; Iskandrian, A.S. )

    1991-05-21

    Dipyridamole cardiac imaging is a useful alternative to exercise stress testing in the evaluation of patients with ischemic heart disease. Intravenous dipyridamole has been approved recently for clinical use. Oral dipyridamole is widely available. The hemodynamic effects of dipyridamole include an increase in coronary blood flow in excess of the increase in myocardial oxygen consumption and cardiac output. The quality of the thallium images is better or similar to that of exercise thallium images. The optimal dose of intravenous dipyridamole is 0.56 mg/kg and the optimal oral dose is 300-375 mg, although higher doses may be necessary in some patients. The sensitivity and specificity of dipyridamole-thallium imaging, whether intravenous or oral, have been shown in a number of studies to be quite adequate and comparable to that achieved during exercise thallium imaging. Dipyridamole-thallium imaging has also been useful in identifying high-risk patients undergoing major elective vascular surgery. The relative merits of dipyridamole imaging versus exercise testing after acute myocardial infarction require further studies.83 references.

  14. Assessment of transient left ventricular dilation ratio via 2-day dipyridamole Tc-99m sestamibi nongated myocardial perfusion imaging.

    PubMed

    Kakhki, Vahid Reza Dabbagh; Sadeghi, Ramin; Zakavi, Seyed Rasoul

    2007-07-01

    The definition of an abnormal transient ischemic dilation (TID) ratio may be different according to stress type, type of isotope, and imaging protocols. The aim of this study was to derive the normal threshold and assessment of the TID ratio via 2-day dipyridamole stress/rest technetium 99m sestamibi myocardial perfusion single photon emission computed tomography (MPS). We performed 2-day dipyridamole stress/rest Tc-99m sestamibi MPS in 665 patients. The TID ratio was calculated automatically with the Emory Cardiac Toolbox. The upper limit of normal (1.19) for the TID ratio was derived from 131 patients with a low (<5%) likelihood of coronary artery disease as mean + 2 SDs. Patients with complete or partial reversible defects or multivessel-type or left anterior descending artery (LAD) territory perfusion abnormalities had higher TID ratios than the other patients. These patients had a higher frequency of an abnormal TID ratio (>1.19) as well. Binary logistic regression analysis showed that ischemia and LAD territory perfusion abnormality were independent predictors of an abnormal TID ratio. The threshold for an abnormal TID ratio via 2-day post-dipyridamole stress/rest Tc-99m sestamibi MPS was greater than 1.19. By use of this protocol, TID is not uncommon and it is related to a greater amount of ischemic burden as well as multivessel-type or LAD territory perfusion abnormality.

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

    SciTech Connect

    Leppo, J.; Boucher, C.A.; Okada, R.D.; Newell, J.B.; Strauss, H.W.; Pohost, G.M.

    1982-09-01

    After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial thallium-201 scans were obtained in 60 patients undergoing cardia catheterization. Forty patients had significant (greater than or equal to50% 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 thallium-201 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 anlaysis 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. It is concluded 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.

  16. Failure of dipyridamole-thallium myocardial imaging to detect severe coronary disease

    SciTech Connect

    Chin, W.; Go, R.; Lenehan, S.; Underwood, D.A.

    1989-09-01

    Three patients referred for peripheral vascular surgery who died of coronary artery disease complications despite normal dipyridamole-thallium scans are discussed. Although recent literature has shown enthusiasm for this test in this clinical setting, the dipyridamole-thallium scans are not absolute and patients remain at risk for major coronary artery events. Careful clinical screening and awareness of the signs of left main coronary disease on thallium images are important in the evaluation of these patients.

  17. A new myocardial perfusion scintigraphy stress protocol combining dipyridamole-dobutamine-atropine.

    PubMed

    Lima, Ronaldo Souza Leão; De Lorenzo, Andrea; Machado, Luiz S; Oliveira, Bernardo N; Pellini, Marcos P

    2012-03-01

    Pharmacological stress is often used, and the drugs most frequently utilized are dipyridamole (Dip) and dobutamine (Dob). We aimed to evaluate the safety and the results obtained with a new protocol associating Dip, Dob, and atropine, compared with the Dip protocol. Thirty-two patients underwent rest Tl/Dip stress Tc-sestamibi myocardial perfusion tomography on the same day. Dip was administered intravenously (0.56 mg/kg) for 4 min, and Tc-sestamibi was injected 3 min after the end of the Dip injection. On another day, patients received the same Dip dose, immediately followed by the infusion of Dob [20 μg/kg/min for the first 2 min and 40 μg/kg/min in the next 2 min, with atropine (1 mg) given in the interval between the two Dob doses]. Images were acquired with a two-detector camera. In a 17-segment model of the left ventricle, each segment was automatically scored 0-4 (normal to absent radiotracer activity), and perfusion scores were obtained as the sum of stress score and sum of rest segmental score (SSS and SRS, respectively) and the difference between them [summed difference score (SDS)]. All scans were interpreted by two experienced physicians as either definitely normal, probably normal, probably abnormal, or definitely abnormal. No serious complication was found independently of the protocol used. Heart rate and systolic and diastolic blood pressure were similar in both protocols at the basal level. Maximum heart rate (126 ± 21 vs. 82.7 ± 13.6, P<0.001) and the double product (18816 ± 4194 vs. 11449 ± 2438, P<0.001) showed a significant increase in the tests that used Dob and atropine compared with the Dip protocol. Stress studies with Dip-Dob had higher SSS compared with the Dip protocol (9.4 ± 10.1 vs. 7.7 ± 8.8, P<0.001). SDS was also higher in the Dip-Dob protocol than in the Dip protocol (6.1 ± 6.8 and 4.8 ± 5.8, respectively, P< 0.001). This work shows that a new protocol of pharmacological stress with a combination of Dip, Dob, and atropine

  18. Comparison of coronary angiography and early oral dipyridamole thallium-201 scintigraphy in patients receiving thrombolytic therapy for acute myocardial infarction

    SciTech Connect

    Jain, A.; Hicks, R.R.; Myers, G.H.; McCarthy, J.J.; Perry, J.R.; Adams, K.F. )

    1990-10-01

    We evaluated 50 consecutive patients who received thrombolytic therapy for acute myocardial infarction using thallium-201 single photon emission computed tomography in combination with oral dipyridamole to assess the frequency of residual myocardial ischemia. Thallium studies were performed early after myocardial infarction at a mean of 4.6 days. The time from the onset of chest pain to the administration of thrombolytic therapy was 2.6 hours (range 0.5 to 5.5). Q wave myocardial infarction was evident in 46 patients; four patients had a non-Q wave infarction (anterior infarction in 31 patients and inferior infarction in 19 patients). The serum mean peak creatinine kinase was 1503 IU/L (range 127 to 6500). Coronary angiography was performed in all patients at a mean of 3.1 days (range 2 to 10) and revealed the infarct-related vessel to be patent in 36 patients (72%). The ejection fraction was 48% (range 26% to 67%). After dipyridamole administration, 13 patients (26%) developed angina that was easily reversed with the administration of intravenous aminophylline. Systolic blood pressure decreased from 122 to 115 mm Hg (p less than 0.05) and the heart rate increased from 76 to 85 beats/min (p less than 0.05). None of the patients had significant hypotension, arrhythmias, or evidence of infarct extension. Perfusion abnormalities were present on the initial thallium images in 48 patients. Redistribution suggestive of ischemia was present in 36 patients (72%). Ischemia confined to the vascular distribution of the infarct vessel was evident in 22 patients. Seven patients had ischemia in the infarct zone as well as in a remote myocardial segment. Thus 29 patients (58%) had ischemia in the distribution of the infarct vessel. Ischemia in the infarct zone was evident in 19 of 36 patients with open infarct vessels and in 10 of 14 patients with occluded infarct vessels.

  19. Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation

    SciTech Connect

    Mays, A.E. Jr.; Cobb, F.R.

    1984-05-01

    This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow.

  20. Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation.

    PubMed Central

    Mays, A E; Cobb, F R

    1984-01-01

    This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow

  1. Visual and semi-quantitative assessment of brain tumors using (201)Tl-SPECT.

    PubMed

    Nose, Ayumi; Otsuka, Hideki; Nose, Hayato; Otomi, Yoichi; Terazawa, Kaori; Harada, Masafumi

    2013-01-01

    To evaluate the usefulness of (201)Tl-SPECT in differentiating benign from malignant brain tumors. Eighty-eight patients (44 males and 44 females) with 58 high-grade (WHO grade III-IV) and 30 low-grade (WHO grade I-II) tumors were evaluated with (201)Tl-SPECT. (1) Visual assessment was performed by board-certificated radiologists using (201)Tl-SPECT. Tumors were classified in two groups (Tl-positive and Tl-negative) and scored using the five grade evaluation system. Receiver operating characteristic (ROC) analysis was performed in the Tl-positive group. (2) Semi-quantitative assessment involved measurement of early and delayed (201)Tl uptake, and the retention index (RI) was applied as follows: RI=delayed uptake ratio/early uptake ratio. Three combinations of RI using mean and maximum values of the region of interest were calculated. (1) Seventy-four Tl-positive and 14 Tl-negative tumors. The area under the ROC curve (AUC) estimated by three radiologists exceeded a value of 0.7. The value was greater when estimated by the more experienced radiologist. (2) In all RIs, the difference of RI between high-grade tumors and low-grade tumors was statistically significant. A visual and semi-quantitative assessment using (201)Tl-SPECT was found to be useful for differentiating benign from malignant brain tumors.

  2. Decreased coronary vasodilatory capacity in hypertrophic cardiomyopathy determined by split-dose thallium-dipyridamole myocardial scintigraphy

    SciTech Connect

    Koga, Y.; Yamaguchi, R.; Ogata, M.; Kihara, K.; Toshima, H. )

    1990-05-01

    Split-dose thallium-dipyridamole myocardial scintigraphy was performed in patients with nonobstructive hypertrophic cardiomyopathy (HC) who had angiographically normal coronary arteries. The dipyridamole-induced increases in thallium-201 uptake, calculated to evaluate coronary vasodilatory capacity, were significantly lower in 30 patients with HC than in 13 control subjects (177 +/- 58 vs 281 +/- 46%) and the reductions were observed in both the septal and lateral segments. The reductions of the septal segment in HC patients were significantly greater than those in 10 hypertensive patients with comparable degrees of septal hypertrophy. Of patients with HC, 16 had increases in thallium uptake well below the normal range. Compared with those having normal increases, these patients had significantly lower exercise duration (11 vs 15 minutes), with 33% having ST depression develop at a workload less than or equal to 80 watts. These data indicate that approximately one-half of patients with HC have impaired coronary vasodilatory capacity that could be an important pathophysiologic abnormality of HC resulting in the development of myocardial ischemia and the impairment of cardiac performance during exercise.

  3. Effects of dipyridamole and aminophylline on hemodynamics, regional myocardial blood flow and thallium-201 washout in the setting of a critical coronary stenosis

    SciTech Connect

    Granato, J.E.; Watson, D.D.; Belardinelli, L.; Cannon, J.M.; Beller, G.A. )

    1990-12-01

    Experiments were performed to characterize the interaction of intravenous dipyridamole and aminophylline on thallium-201 transport kinetics, regional myocardial blood flow and systemic hemodynamics in the presence of a critical coronary artery stenosis. In 12 dogs with a critical left anterior descending coronary artery stenosis, arterial pressure decreased from a mean value (+/- SEM) of 107 +/- 6 to 94 +/- 3 mm Hg and distal left anterior descending artery pressure decreased from 70 +/- 7 to 55 +/- 4 mm Hg after intravenous administration of dipyridamole. In the left anterior descending perfusion zone, the endocardial/epicardial flow ratio decreased from 0.70 to 0.36 and the intrinsic thallium washout rate was significantly prolonged. Intravenous aminophylline reversed the dipyridamole-induced systemic hypotension and transmural coronary steal and restored the thallium washout rate to baseline values. In six other dogs, aminophylline alone resulted in no alterations in systemic and coronary hemodynamics or regional myocardial blood flow. As expected, dipyridamole-induced vasodilation and coronary steal were prevented by aminophylline pretreatment. These data show that in a canine model of partial coronary stenosis, systemic hypotension, adverse regional flow effects and prolonged thallium-201 washout consequent to intravenously administered dipyridamole are promptly reversed by intravenous aminophylline administration. Aminophylline alone had no significant hemodynamic and coronary flow effects. This study provides further insight into the altered thallium kinetics occurring as a consequence of dipyridamole-induced vasodilation and suggests that the prompt reversal of symptoms and signs of ischemia with aminophylline in patients receiving intravenous dipyridamole for clinical imaging studies probably reflects the reversal of transmural coronary steal.

  4. Higher events rate in patients with a normal gated myocardial perfusion imaging with dipyridamole than exercise: “Run for reliability”

    PubMed Central

    Fatima, Nosheen; uz Zaman, Maseeh; Ishaq, Mohd; Rasheed, S Zahed; Baloch, Dad J; Wali, Asif; Bano, Javeria; Rehman, Kawish

    2012-01-01

    Objective: The aim of this is to evaluate the negative predictive value (NPV) of a normal gated myocardial perfusion imaging (NGMPI) with exercise and dipyridamole in a propensity matched population. Materials and Methods: This is a prospective study conducted at Nuclear Cardiology Department of Karachi Institute of Heart Diseases, Karachi from December 2008 until June 2010. A total of 809 patients with a NGMPI with adequate exercise (558/809) or dipyridamole (251/809) stress were included and followed-up for 12-30 months (mean 24 ± 3 months) for fatal or non-fatal myocardial infarctions (MI). Results: Mean ejection fraction (%), end diastolic volume (ml), and end systolic volume (ml) in exercise and dipyridamole cohorts were (72 ± 08, 66 ± 11), (68 ± 13, 81 ± 17), and (19 ± 11, 26 ± 12) respectively. On follow-up, in dipyridamole cohort 2 fatal and 6 non-fatal MIs were reported. While in exercise cohort only 2 non-fatal MIs were reported. The NPV of a NGMPI with exercise was 99.7% (95% confidence interval [CI] 98.93-99.96%) with an event rate of 0.3% (95% CI; 0.03-0.6%) and annualized event rate of 0.15%. The NPV of NGMPI with dipyridamole was 96.80% (95% CI; 2.2-4.3%) with an event rate of 3.2% (95% CI; 1.39-3.83%) and annualized event rate of approximately 1.6%. Event free survival for dipyridamole group was significantly lower than exercise analyzed by Log-rank test (14.509, P < 0.001). Conclusion: A NGMPI with dipyridamole stress has higher event rate (low-NPV) as compared with exercise and this raises concern over its credibility to label these patients into low-risk group. PMID:23919070

  5. Ability of dipyridamole-thallium-201 imaging one to four days after acute myocardial infarction to predict in-hospital and late recurrent myocardial ischemic events

    SciTech Connect

    Brown, K.A.; O'Meara, J.; Chambers, C.E.; Plante, D.A. )

    1990-01-15

    The ability of dipyridamole-thallium-201 imaging to predict in-hospital and late cardiac events when performed very early (62 +/- 21 hours, range 23 to 102) after acute myocardial infarction (AMI) was tested in 50 patients. During hospitalization, 1 patient developed recurrent AMI and 8 patients developed recurrent angina after MI associated with ST-segment depression at 60 +/- 42 hours after the dipyridamole-thallium-201 imaging; of these, 6 required urgent coronary revascularization. No patient died in-hospital. There were no serious adverse effects during the dipyridamole protocol. Using stepwise multivariate logistic regression analysis, the best and only statistically significant predictor of in-hospital ischemic cardiac events was the presence of thallium-201 redistribution within the infarct zone (p = 0.0001). Of 20 patients with infarct zone thallium-201 redistribution, 9 (45%) developed in-hospital ischemic cardiac events compared to 0 of 30 patients without infarct zone thallium-201 redistribution (p less than 0.0001). During a follow-up 12 +/- 7 months after discharge, 3 additional patients with infarct zone thallium-201 redistribution developed recurrent AMI or unstable angina, whereas no patient without infarct zone thallium-201 redistribution developed ischemic cardiac events. These data suggest that dipyridamole-thallium-201 imaging performed very early after AMI may identify a subgroup of patients at high risk for in-hospital and late ischemic cardiac events. Such patients may benefit from early cardiac catheterization and revascularization. Patients without infarct zone thallium-201 redistribution appear to be at very low risk for in-hospital and late ischemic cardiac events and may be candidates for early discharge.

  6. Dipyridamole cardiac imaging

    SciTech Connect

    Iskandrian, A.S.; Heo, J.; Askenase, A.; Segal, B.L.; Auerbach, N.

    1988-02-01

    Dipyridamole cardiac imaging is a useful alternative technique to exercise stress testing in the evaluation of patients with ischemic heart disease. Intravenous dipyridamole is still in the investigational phase, while oral dipyridamole is widely available. The hemodynamic effects of dipyridamole include an increase in coronary blood flow (due to coronary vasodilation) which is in excess of the increase in myocardial oxygen consumption and cardiac output. The disparity in the increase in coronary blood flow relative to the cardiac output results in an increase in myocardial thallium activity and an increase in the myocardial/background activity ratio. The quality of the thallium images is better or similar to that of exercise thallium images. The optimal dose of intravenous dipyridamole is 0.56 mg/kg, and of the oral dose it is 300 to 400 mg, although higher doses may be necessary in some patients. Analysis of the thallium images has been to a large extent based on visual inspection of the planar images. Delayed images are helpful to establish the nature of the perfusion abnormalities (transient or fixed). The process of redistribution is based on disparate rates of washout from the normal and abnormal zones. The sensitivity and specificity of dipyridamole thallium imaging, whether intravenous or oral, have been shown in a number of studies to be quite adequate and comparable to that achieved during exercise thallium imaging. Dipyridamole two-dimensional echocardiography has also been used in the detection of coronary artery disease; transient (new or worsening of preexisting) wall motion abnormalities have been found to be a specific marker of coronary artery disease. Transmural as well as regional coronary steal phenomena have been postulated as the mechanism for dipyridamole-induced regional wall motion abnormalities. 65 references.

  7. Significance of increased lung thallium-201 activity on serial cardiac images after dipyridamole treatment in coronary heart disease

    SciTech Connect

    Okada, R.D.; Dai, Y.H.; Boucher, C.A.; Pohost, G.M.

    1984-02-01

    Increased lung thallium-201 (Tl-201) activity occurs in patients with severe coronary artery disease (CAD) on initial postexercise images. To determine the significance of assessing lung Tl-201 on serial imaging after dipyridamole therapy, initial and delayed (2 to 3 hours) Tl-201 imaging was performed in 40 patients with CAD and 26 normal control subjects. Lung Tl-201 activity was quantitated as a percentage of maximal myocardial activity for each imaging time (lung Tl-201 index). The mean initial lung Tl-201 activity was 42 +/- 2% (+/- standard error of the mean) in 26 control subjects, 56 +/- 2% in 25 patients with 2- or 3-vessel CAD (p less than 0.001) and 53 +/- 2% in 15 patients with 1-vessel CAD (p less than 0.005 compared with control subjects) (difference not significant between 1-vessel and multivessel CAD). Dipyridamole lung Tl-201 activity decreased relative to the myocardium from initial to delayed images (p less than 0.001) in patients with CAD but not in control subjects. When a dipyridamole lung Tl-201 index of 58% (mean +/- 2 standard deviations for control subjects) was chosen as the upper limit of normal, 14 of 40 of the CAD patients (35%) had abnormal values and all control patients had values within normal limits. These 14 patients with CAD and abnormal initial lung Tl-201 indexes had rest ejection fractions that were not significantly different from those in patients with CAD, and normal initial dipyridamole lung Tl-201 index (58 +/- 4% and 63 +/- 2%, respectively).

  8. Cardiac arrest during dipyridamole imaging

    SciTech Connect

    Blumenthal, M.S.; McCauley, C.S.

    1988-05-01

    A case of cardiac arrest and subsequent acute myocardial infarction occurring during thallium-201 imaging with oral dipyridamole augmentation is presented. Previous reports emphasizing the safety of this procedure are briefly reviewed and a recommendation for close hemodynamic and arrhythmia monitoring during the study is made. Large doses of oral dipyridamole may be contraindicated in patients with unstable angina.

  9. Thallium-201 myocardial imaging after pharmacologic coronary vasodilation: Preliminary results of a comparison between oral and intravenous administration of dipyridamole

    SciTech Connect

    Taillefer, R.; Lette, J.; Phaneuf, D.C.; Lemire, F.; Leveille, J.

    1985-05-01

    Although the diagnostic utility of Tl-201 myocardial imaging after dipyridamole (DIP) infusion is well established, the intravenous form of the drug is not commercially available. The author prospectively studied 34 consecutive patients referred for coronary angiography. With in a 2 week period, each patient underwent cardiac catheterization and Tl-201 myocardial imaging following both oral and i.v. DIP. With the patient supine, DIP was infused at a rate of 0.56 mg/kg over 4 minutes. Tl-201 was injected 3 min. after the end of the infusion with the patient standing. Myocardial imaging was performed in 3 views at 3 min. and 4 hrs after Tl-201 injection. All patients were then randomized to either 200 mg or 400 mg of oral DIP. Imaging protocol was similar to the i.v. technique, except for a delay of 45-60 min. before Tl-201 injection. Myocardial regional perfusion was evaluated by 2 independent observers using original analog and background substracted digital images with segmental profile analysis. For the 17 patients who recieved DIP 400 mg, the sensitivity was 75%(9/12) with the infusion and 83% (10/12) with the oral dose. Side effects were minor and less frequent with the oral DIP. Despite the small number of patients studied, Tl-201 imaging following 400 mg oral DIP administration proved to be reliable alternative to the intravenously induced coronary vasodilation.

  10. Improved specificity of myocardial thallium-201 single-photon emission computed tomography in patients with left bundle branch block by dipyridamole

    SciTech Connect

    Burns, R.J.; Galligan, L.; Wright, L.M.; Lawand, S.; Burke, R.J.; Gladstone, P.J. )

    1991-08-15

    Reduced septal uptake of thallium-201 during exercise is frequently observed in patients with left bundle branch block (LBBB) and normal coronary arteries. This may reflect normal coronary autoregulation in response to lower septal oxygen demand; thus, dipyridamole, which uniformly exploits flow reserve, would be more accurate for diagnosis of coronary artery disease (CAD). Sixteen patients with LBBB underwent exercise and dipyridamole thallium-201 single-photon emission computed tomography and coronary angiography within 3 months. Sensitivity for detection of left anterior descending CAD (greater than 50% stenosis) was 0.83 for exercise and 1.00 for dipyridamole. Specificity was 0.30 (visual) or 0.20 (quantitative analysis) for exercise and 0.80 (visual) or 0.90 (quantitative) for dipyridamole (p less than 0.05). Dipyridamole combined with quantitative analysis also improved specificity of CAD detection overall (p less than 0.01). These data demonstrate that pharmacologic vasodilation is more accurate than exercise when diagnosing CAD by myocardial perfusion scintigraphy in patients with LBBB.

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

    SciTech Connect

    Siegel, M.E.; Stewart, C.A.; Kwong, P.; Sakimura, I.

    1982-04-01

    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 /sup 201/Tl 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 /sup 201/Tl in 20 out of 23. Ultrasound correctly predicted non-healing in 3 out of 6 cases, compared with 5 out of 6 for /sup 201/Tl. The positive predictive value of the /sup 201/Tl study was 63%, versus 27% for ultrasound, and the negative predictive value was 95% for /sup 201/Tl and 83% for ultrasound. The accuracy of /sup 201/Tl and ultrasound was 86% and 62%, respectively. This limited study suggests that /sup 201/Tl perfusion scanning is a useful noninvasive test of ulcer healing potential and may be more sensitive than Doppler ultrasound.

  12. Technetium-99m sestamibi myocardial imaging: Same-day rest-stress studies and dipyridamole

    SciTech Connect

    Taillefer, R. )

    1990-10-16

    Unlike thallium-201, technetium-99m (Tc-99m) sestamibi does not redistribute in the myocardium after injection. Thus, 2 separate injections, 1 at rest and the other at stress (or after dipyridamole), are required to differentiate ischemia from scar. From a physical viewpoint, a 24-hour interval between the 2 injections is preferable for detection of coronary artery disease (CAD) with Tc-99m sestamibi imaging. However, same-day studies are more convenient in clinical practice. Results of studies using different Tc-99m sestamibi injection protocols are presented with emphasis on the advantages of a rest-stress injection sequence with a low dose at rest (7 mCi) followed 2 hours later by a higher dose at stress (25 mCi). A prospective study was conducted in a patient population with proven CAD using same-day studies to compare a rest-stress (7 and 25 mCi, respectively) to a stress-rest (7 and 25 mCi) Tc-99m sestamibi injection sequence. There was an agreement in 87.3% of the analyzed segments between the 2 protocols. However, the largest discordance for type of defect applied to 7.4% of the segments judged ischemic in the rest-stress protocol, which were called scars on stress-rest. This study showed that a rest-stress sequence is preferable when using a same-day protocol with a short time interval (less than 2 hours) between the 2 Tc-99m sestamibi injections because the rest image performed initially represents a true rest study, which is not necessarily the case with the stress-rest sequence. Preliminary studies were performed to evaluate dipyridamole with Tc-99m sestamibi imaging in normal subjects and in patients with CAD. These studies showed that treadmill and dipyridamole Tc-99m sestamibi imaging are comparable and the results are similar to those obtained with thallium-201.

  13. Myocardial imaging using thallium 201 scintigraphy after dipyridamole infusion: A case history

    SciTech Connect

    Niemeyer, M.G.; van der Wall, E.E.; Leijtens, J.P.; Wever, J.; van der Pol, J.M.; Willekens, F.G. )

    1989-12-01

    Coronary artery disease frequently occurs in combination with peripheral vascular disorders and is an important cause of morbidity and mortality during or after peripheral vascular surgery. However, the detection of coronary artery disease in patients with peripheral vascular disease may be complicated, since most of these patients are unable to perform conventional exercise testing. The authors report a sixty-two-year-old man with an infrarenally located aneurysm of the abdominal aorta who underwent thallium 201 scintigraphy combined with dipyridamole infusion as an alternative exercise test. The subsequent thallium 201 images showed perfusion defects indicative of severe coronary artery disease. Coronary angiography showed an occluded right coronary artery and a significant proximal stenosis in the left anterior descending coronary artery. The patient underwent successful aortocoronary bypass surgery, and two months later, the aortic aneurysm was operated on without complications. As a result, dipyridamole thallium 201 scintigraphy should be considered as a valuable diagnostic test to detect coronary artery disease in patients with peripheral vascular disorders.

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

    SciTech Connect

    Cannon, R.O. 3d.; Dilsizian, V.; O'Gara, P.T.; Udelson, J.E.; Schenke, W.H.; Quyyumi, A.; Fananapazir, L.; Bonow, R.O. )

    1991-05-01

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

  15. 201Tl+-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  16. Clinical relevance of 201Tl-chloride SPET in the differential diagnosis of brain tumours.

    PubMed

    Staffen, W; Hondl, N; Trinka, E; Iglseder, B; Unterrainer, J; Ladurner, G

    1998-04-01

    Magnetic resonance imaging (MRI) and computed tomography (CT) may not be reliable in the differential diagnosis of tumour necrosis, scar and recurrent tumour. We compared 201Tl-chloride SPET with CT and MRI for the differential diagnosis of these cerebral lesions. Brain SPET was performed in 40 patients after the intravenous injection of 201Tl-chloride. All 40 patients also had a CT or MRI scan, and a histological diagnosis was available for 27 of the patients. For each patient, the ratio of counts in the lesion region of interest (ROI) to counts in the contralateral ROI was calculated and found to be between 0.58 and 9.60. The ratios for high-grade gliomas, metastases and meningiomas were high (> 2.7), especially in tumours with good vascularization. A low ratio (< 1.7) was noted in patients with low-grade astrocytoma, necrosis or ischaemic lesions. There were two exceptional cases of ischaemic lesions in the luxury perfusion stage (ratios of 3.61 and 3.87), as verified by HMPAO-SPET. We found that 201Tl-chloride SPET helps to differentiate between malignant tumours, poorly vascularized benign lesions and necrosis. Differentiation between low-grade astrocytoma and non-malignant lesions was not possible, but there was a trend towards differentiating between low-grade astrocytoma and ischaemic infarction. The timing of the investigation is important to avoid false-positive results in hyperperfused ischaemic tissue.

  17. Postoperative myocardial infarction and cardiac death. Predictive value of dipyridamole-thallium imaging and five clinical scoring systems based on multifactorial analysis

    SciTech Connect

    Lette, J.; Waters, D.; Lassonde, J.; Dube, S.; Heyen, F.; Picard, M.; Morin, M. )

    1990-01-01

    Sixty-six patients unable to complete a standard preoperative exercise test because of physical limitations were studied to determine the predictive value of individual clinical parameters, of clinical scoring systems based on multifactorial analysis, and of dipyridamole-thallium imaging before major general and vascular surgery. Study endpoints were limited to postoperative myocardial infarction or cardiac death before hospital discharge. There were nine postoperative cardiac events (seven deaths and two nonfatal infarctions). There was no statistical correlation between cardiac events and preoperative clinical descriptors, including individual clinical parameters, the Dripps-American Surgical Association score, the Goldman Cardiac Risk Index score, the Detsky Modified Cardiac Risk Index score, Eagle's clinical markers of low surgical risk, and the probability of postoperative events as determined by Cooperman's equation. There were no cardiac events in 30 patients with normal dipyridamole-thallium scans or in nine patients with fixed myocardial perfusion defects. Of 21 patients with reversible perfusion defects who underwent surgery, nine had a postoperative cardiac event (sensitivity, 100%; specificity, 43%). In the six other patients with reversible defects, preoperative angiography showed severe coronary disease or cardiomyopathy. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically before major general and vascular surgery, whereas dipyridamole-thallium imaging successfully identified all patients who sustained a postoperative cardiac event.

  18. Estimation of potential excess cancer incidence in pediatric 201Tl imaging.

    PubMed

    Kaste, Sue C; Waszilycsak, George L; McCarville, M Beth; Daw, Najat C

    2010-01-01

    Little information is available regarding doses of ionizing radiation from medical imaging in the growing population of children undergoing therapy for cancer who are at risk of developing second cancers. The purpose of our study was to estimate the potential excess lifetime cancer incidence and mortality associated with thallium bone imaging in pediatric patients. We retrospectively reviewed the medical records of pediatric patients treated between August 1991 and December 2003 for newly diagnosed osteosarcoma who underwent 201Tl imaging as part of the treatment protocol. According to age at diagnosis and doses of 201Tl, we estimated the excess cancer incidence and cancer mortality for boys and girls at 5 and 15 years old. The study cohort consisted of 73 patients, 32 males (median age at diagnosis, 14.8 years; age range, 8.1-20.1 years) and 41 females (median age at diagnosis, 13.3 years; age range, 6.0-20.7 years). Patients underwent a total of three 201Tl studies with a median dose of 4.4 mCi (162.8 MBq) (range, 2.2-8.4 mCi [81.4-310.8 MBq]) per study. Total median cumulative patient radiation dose for 201Tl studies was 18.6 rem (186 mSv) (range, 8.4-44.2 rem [84-442 mSv]) for males and 21.5 rem (215 mSv) (range, 7.0-43.8 rem [70-438 mSv]) for females. Estimated excess cancer incidence was 6.0 per 100 (male) and 13.0 per 100 (female) if exposed by 5 years of age; 2.0 per 100 (male) and 3.1 per 100 (female) by 15 years of age. Estimated excess cancer mortality was 3.0 per 100 for males and 5.2 per 100 for females at 5 years of age; 1.0 per 100 (male) and 1.4 per 100 (female) exposed at 15 years of age. Further reduction of doses in younger patients is needed to consider 201Tl a viable option for imaging osteosarcoma.

  19. Monte Carlo evaluation of accuracy and noise properties of two scatter correction methods for /sup 201/Tl cardiac SPECT

    NASA Astrophysics Data System (ADS)

    Narita, Y.; Iida, H.; Ebert, S.; Nakamura, T.

    1997-12-01

    Two independent scatter correction techniques, transmission dependent convolution subtraction (TDCS) and triple-energy window (TEW) method, were evaluated in terms of quantitative accuracy and noise properties using Monte Carlo simulation (EGS4). Emission projections (primary, scatter and scatter plus primary) were simulated for three numerical phantoms for /sup 201/Tl. Data were reconstructed with ordered-subset EM algorithm including noise-less transmission data based attenuation correction. Accuracy of TDCS and TEW scatter corrections were assessed by comparison with simulated true primary data. The uniform cylindrical phantom simulation demonstrated better quantitative accuracy with TDCS than with TEW (-2.0% vs. 16.7%) and better S/N (6.48 vs. 5.05). A uniform ring myocardial phantom simulation demonstrated better homogeneity with TDCS than TEW in the myocardium; i.e., anterior-to-posterior wall count ratios were 0.99 and 0.76 with TDCS and TEW, respectively. For the MCAT phantom, TDCS provided good visual and quantitative agreement with simulated true primary image without noticeably increasing the noise after scatter correction. Overall TDCS proved to be more accurate and less noisy than TEW, facilitating quantitative assessment of physiological functions with SPECT.

  20. Assessment of the ability of myocardial contrast echocardiography with harmonic power Doppler imaging to identify perfusion abnormalities in patients with Kawasaki disease at rest and during dipyridamole stress.

    PubMed

    Ishii, M; Himeno, W; Sawa, M; Iemura, M; Furui, J; Muta, H; Sugahara, Y; Egami, K; Akagi, T; Ishibashi, M; Kato, H

    2002-01-01

    The aim of our study was to assess the ability of myocardial contrast echocardiography (MCE) with harmonic power Doppler imaging (HPDI) to identify perfusion abnormalities in patients with Kawasaki disease at rest and during pharmacological stress imaging with dipyridamole. Results were compared with those of 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) imaging as the clinical reference standard. MCE with HPDI was performed on 20 patients with a history of Kawasaki disease. Images were obtained at baseline and during dipyridamole infusion (0.56 mg x kg(-1)) in the apical two- and four-chamber views. Myocardial opacification suitable for the analysis was obtained in all patients. Nine patients with stenotic lesions had a reversible defect after dipyridamole infusion detected by both MCE with HPDI and SPECT, and 3 patients with a history of myocardial infarction had a partially or completely irreversible defect detected by both methods. Three patients with coronary aneurysm without stenotic lesion, 4 patients with regressed coronary aneurysm, and 2 patients with normal coronary artery in acute phase also had normal perfusion at rest and after pharmacological stress by both methods. A 96% concordance (kappa = 0.87) was obtained when comparing the respective segmental perfusion scores using the two methods at baseline, and an 86% concordance (kappa = 0.81) was obtained at postdipyridamole infusion. After combining baseline and postdipyridamole images, each segment was labeled as having normal perfusion, irreversible defects, or reversible defects. Using these classifications, concordance for the two methods was 92% (kappa = 0.87). MCE with HPDI is a safe and feasible method by which to detect asymptomatic ischemia due to severe stenotic lesion, and it may be an important addition to the modalities used to identify patients at risk for myocardial infarction as a complication of Kawasaki disease.

  1. Incidence of caffeine in serum of patients undergoing dipyridamole myocardial perfusion stress test by an intensive versus routine caffeine history screening.

    PubMed

    Banko, Lesan T; Haq, Salman A; Rainaldi, Debroah A; Klem, Igor; Siegler, Jason; Fogel, Joshua; Sacchi, Terrence J; Heitner, John F

    2010-05-15

    The coronary vasodilatory effect of dipyridamole is competitively blocked by caffeine. The purposes of this study were to (1) assess the incidence of having detectable serum caffeine and (2) evaluate whether an intensive caffeine history screening strategy was superior to routine history screening before dipyridamole myocardial perfusion imaging. One hundred ninety-four patients who were randomized to an intensive or a routine screening history strategy were prospectively evaluated. Serum caffeine levels were determined in all patients. Outcomes data, including death, nonfatal myocardial infarction, and history of revascularization, were obtained at 24 months. Nearly 1 in 5 patients (19%) who screened negative by history had detectable serum caffeine. In patients who screened negative by history, there was no statistically significant difference in the percentage of caffeine seropositivity between the intensive and routine arms (16% vs 22%, respectively, p = 0.31). The incidence of combined end points of death, myocardial infarction, or revascularization was 22.9% and 7.3% in patients with and without detectable serum caffeine, respectively (p = 0.01). In conclusion, despite initial negative results on screening by history, a considerably high percentage of patients had positive serum caffeine levels. These results do not support the use of an intensive screening strategy. Detectable serum caffeine was associated with a higher incidence of adverse outcomes.

  2. Dipyridamole-thallium-201 tomography documenting improved myocardial perfusion with therapy in Kawasaki disease

    SciTech Connect

    Nienaber, C.A.; Spielmann, R.P.; Hausdorf, G.

    1988-12-01

    Thallium-201 tomographic perfusion studies after pharmacologic vasodilation were performed in seven children (aged 2 years 8 months to 8 years 7 months), 3 to 20 months after the acute stage of the disease. In all patients coronary aneurysms were seen on cross-sectional echocardiograms. The scintigrams of six children showed no significant regional reduction of myocardial thallium-201 uptake. These children had remained asymptomatic in the follow-up period after the acute inflammatory stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with acute posterolateral myocardial infarction; obstruction of two coronary vessels supplying the defect zones was confirmed by contrast angiography. After 8 months of treatment a follow-up nuclear scan showed marked reduction in the size of the defect and almost complete abolishment of the ischemic reaction. Thus tomographic thallium-201 perfusion scintigraphy in conjunction with vasodilation stress is useful to assess myocardial perfusion in children with Kawasaki disease and demonstrates marked improvement in regional perfusion after adequate medical therapy.

  3. Comparison of early exercise treadmill test and oral dipyridamole thallium-201 tomography for the identification of jeopardized myocardium in patients receiving thrombolytic therapy for acute Q-wave myocardial infarction

    SciTech Connect

    Jain, A.; Hicks, R.R.; Frantz, D.M.; Myers, G.H.; Rowe, M.W. )

    1990-09-01

    Thrombolytic therapy has become the treatment of choice for patients with acute myocardial infarction. Researchers are not yet able to identify patients with salvage of myocardium who are at risk for recurrent coronary events. Thus, a prospective trial was performed in 46 patients with myocardial infarction (28 anterior and 18 inferior) who received thrombolytic therapy to determine if early thallium tomography (4.7 days) using oral dipyridamole would identify more patients with residual ischemia than early symptom-limited exercise treadmill tests (5.5 days). There were no complications during the exercise treadmill tests or oral dipyridamole thallium tomography. Mean duration of exercise was 11 +/- 3 minutes and the peak heart rate was 126 beats/min. Thirteen patients had positive test results. After oral dipyridamole all patients had abnormal thallium uptake on the early images. Positive scans with partial filling in of the initial perfusion defects were evident in 34 patients. Angina developed in 13 patients and was easily reversed with intravenous aminophylline. Both symptom-limited exercise treadmill tests and thallium tomography using oral dipyridamole were safely performed early after myocardial infarction in patients receiving thrombolytic therapy. Thallium tomography identified more patients with residual ischemia than exercise treadmill tests (74 vs 28%). Further studies are required to determine whether the results of thallium tomography after oral dipyridamole can be used to optimize patient management and eliminate the need for coronary angiography in some patients.

  4. Activity determination of a 201Tl solution by 4πβ-γ and sum-peak coincidence methods

    NASA Astrophysics Data System (ADS)

    Ruzzarin, A.; da Silva, M. A. L.; Iwahara, A.; da Silva, R. L.; Filho, O. L. T.; Poledna, R.; Lopes, R. T.

    2016-07-01

    201Tl is used in nuclear medicine in cardiac imaging for evaluating the injury level in cardiac muscle at rest and exercise. In this work the activity concentration of a 201 Tl radioactive solution has been absolutely determined using the 4πβ-γ coincidence and sum-peak coincidence methods. The presence of 202Tl radioactive impurity that imposes some difficult in the activity measurements was taken into account in the measurements. In the sum-peak method a planar germanium detector was used. The half-lives were evaluated by the reference source method and the results obtained were (3.033 ± 0.004) d and (12.320 ± 0.163) d, respectively, for 201Tl and 202Tl.

  5. A noninvasive method for evaluating portal circulation by administration of /sup 201/Tl per rectum

    SciTech Connect

    Tonami, N.; Nakajima, K.; Hisada, K.; Tanaka, N.; Kobayashi, K.

    1982-11-01

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

  6. Prognostic importance of scintigraphic left ventricular cavity dilation during intravenous dipyridamole technetium-99m sestamibi myocardial tomographic imaging in predicting coronary events.

    PubMed

    McClellan, J R; Travin, M I; Herman, S D; Baron, J I; Golub, R J; Gallagher, J J; Waters, D; Heller, G V

    1997-03-01

    Left ventricular (LV) cavity dilation during stress myocardial perfusion imaging has been associated with multivessel disease, and may be an independent prognostic marker in addition to perfusion defects. The present study examines the predictive value for future cardiac events of transient or fixed LV dilation during dipyridamole technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) imaging. The study included 512 consecutive patients who underwent SPECT imaging with Tc-99m sestamibi after dipyridamole infusion. Transient LV dilation was seen in 70 patients (14%) and 74 had fixed cavity dilation (14%); cavity size was normal in 368 patients (72%). Each perfusion scan was classified as normal or abnormal, and if abnormal, defects were categorized as transient or fixed, and as small, medium, or large (depending upon the number of abnormal vascular territories). Events during a mean follow-up of 12.8 +/- 6.8 months were tabulated by direct review of hospital charts and death certificates. The cardiac event rate (cardiac death or nonfatal infarction) was 1.9% in patients with normal cavity size, 11.4% with transient LV dilation, and 13.5% with fixed LV dilation (p < 0.01). Compared with patients with normal cavity size, those with transient LV dilation were more likely to sustain a myocardial infarction (p < 0.01) and those with fixed dilation more frequently suffered cardiac death (p < 0.01) and hospitalization for heart failure (p < 0.01). The group with the highest risk had both a large perfusion defect and cavity dilation. By Cox proportional hazard regression analysis, both transient and fixed LV dilation were strong independent predictors of cardiac events. Transient or fixed LV dilation are commonly seen during dipyridamole Tc-99m sestamibi SPECT imaging (14% incidence for each) and are useful predictors of cardiac events.

  7. Reproducibility of quantitative planar thallium-201 scintigraphy: quantitative criteria for reversibility of myocardial perfusion defects

    SciTech Connect

    Sigal, S.L.; Soufer, R.; Fetterman, R.C.; Mattera, J.A.; Wackers, F.J. )

    1991-05-01

    Fifty-two paired stress/delayed planar {sup 201}TI studies (27 exercise studies, 25 dipyridamole studies) were processed twice by seven technologists to assess inter- and intraobserver variability. The reproducibility was inversely related to the size of {sup 201}Tl perfusion abnormalities. Intraobserver variability was not different between exercise and dipyridamole studies for lesions of similar size. Based upon intraobserver variability, objective quantitative criteria for reversibility of perfusion abnormalities were defined. These objective criteria were tested prospectively in a separate group of 35 {sup 201}Tl studies and compared with the subjective interpretation of quantitative circumferential profiles. Overall, exact agreement existed in 78% of images (kappa statistic k = 0.66). We conclude that quantification of planar {sup 201}Tl scans is highly reproducible, with acceptable inter- and intraobserver variability. Objective criteria for lesion reversibility correlated well with analysis by experienced observers.

  8. Respiratory arrest during dipyridamole stress testing.

    PubMed Central

    Hillis, G. S.; al-Mohammad, A.; Jennings, K. P.

    1997-01-01

    There is an increasing usage of radionuclide scanning to assess myocardial perfusion, with dipyridamole, the most commonly used stress agent. Although this is an effective, and usually very safe, means by which to assess myocardial blood supply, there have been several incidents of acute bronchospasm in asthmatic patients. There have, however, been no previous reports of respiratory arrest occurring in patients with emphysema. This case illustrates the dangers of administering intravenous dipyridamole, or even adenosine, to patients with chronic lung disease. PMID:9196707

  9. First-pass evaluation of myocardial output during dipyridamole stress using turbo-FLASH magnetic resonance imaging.

    PubMed

    Tello, R; Hartnell, G G; Hill, T C; Cerel, A; Finn, J P; Kamalesh, M; Cohen, M; Lewis, S

    1996-11-01

    This study evaluated the value of dynamically enhanced fast low-angle shot (FLASH) magnetic resonance (MR) imaging in measuring cardiac output with and without dipyridamole pharmacological stress. Ten subjects underwent rest and stress MR imaging. Rest images were acquired using electrocardiogram gated MR (turbo-FLASH: repetition time = 6 mseconds; echo time = 12 mseconds; flip angle = 12 degrees, inversion time = 100) 10 to 45 seconds after intravenous bolus of 0.04 mmol/kg gadolinium (Gd)-DTPA using a Siemens 1.0-tesla Magnetom SP. Stress was induced within the MR imaging scanner with 0.56 mg/kg dipyridamole over 4 minutes with stress MR images obtained after a second bolus of Gd-DTPA in exactly the same position and time intervals. Cardiac output was calculated with a least squares error analysis before and after dipyridamole stress for the left and right ventricles in all 10 patients, and comparison was made with cardiac output by Fick dilution technique during cardiac catheterization in seven patients. This MR analysis methodology shows reasonable correlation (r = 0.953) between left ventricular and right ventricular cardiac output with no effect on cardiac output during immediate dipyridamole stress. Fick dilution studies demonstrated a correlation of 0.96. Turbo-FLASH MR can demonstrate time-activity curves and cardiac output calculations consistent with theoretical predictions.

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

    SciTech Connect

    Rabinovitch, M.; Suissa, S.; Elstein, J.; Staniloff, H.; Tang, A.; Rush, C.; Aldis, A.; Tannous, R.; Turek, M.; Addas, A.

    1986-12-01

    A study was undertaken to determine the effect of gender on criteria for the quantitative analysis of exercise-redistribution /sup 201/Tl 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 /sup 201/Tl 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 /sup 201/Tl myocardial uptake and washout, sex-specific criteria may enhance the predictive accuracy of exercise-redistribution /sup 201/Tl myocardial scintigraphy.

  11. Effect of eating on thallium myocardial imaging

    SciTech Connect

    Wilson, R.A.; Sullivan, P.J.; Okada, R.D.; Boucher, C.A.; Morris, C.; Pohost, G.M.; Strauss, H.W.

    1986-02-01

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

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

    SciTech Connect

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

    1989-07-01

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

  13. A rapid improved method for gamma-spectrometric determination of 202Tl impurities in [201Tl]-labelled radiopharmaceuticals.

    PubMed

    Bonardi, Mauro; Groppi, Flavia; Birattari, Claudio

    2002-11-01

    Despite the cyclotron production method and the efficiency of the radiochemical procedures adopted, the long-lived radio-isotopic impurity 202Tl is always present in [201Tl]-labelled radio-pharmaceuticals, together with other short-lived impurities like, 200Tl. Rapid determination of the 202Tl impurity, can be achieved using HPGe gamma spectrometry and a detector shielded by a 5 mm thick envelope of lead. In this way, dead-time correction errors, Compton and X-ray background, are very efficiently avoided and suppressed. The same method could be applied routinely in nuclear medicine, to determine the radioisotopic purity of 201Tl by means of an ionisation chamber dose calibrator.

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

    SciTech Connect

    Serrano, M.; Olson, A.; Man, C.; Galonsky, R.; Stein, R. )

    1991-03-01

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

  15. Delayed redistribution in thallium 201 SPECT myocardial perfusion studies

    SciTech Connect

    Ziessman, H.A.; Keyes, J.W. Jr.; Fox, L.M.; Green, C.E.; Fox, S.M. )

    1989-11-01

    Stress {sup 201}Tl myocardial perfusion studies are useful in differentiating viable, reversibly ischemic from infarcted myocardium. A perfusion defect that shows redistribution 2 to 4 h after {sup 201}Tl injection is diagnostic of ischemia, while a fixed defect suggests infarction. However, occasional patients with a fixed defect at 4 h have redistribution at 24 h. This study evaluates the frequency and significance of this delayed redistribution with SPECT {sup 201}Tl. Patients with either no or incomplete redistribution at 4 h had repeat imaging 18 to 48 h later. Delayed redistribution was seen in 8/26 (31 percent). Four had incomplete and four had no redistribution at 4 h. Delayed redistribution with SPECT {sup 201}Tl is more common than generally appreciated, and we recommend delayed images in patients with fixed perfusion defects or incomplete redistribution at 4-h imaging, particularly in patients with previous infarctions for whom a revascularization procedure is being considered.

  16. Wiener filtering improves quantification of regional myocardial perfusion with thallium-201 SPECT

    SciTech Connect

    Links, J.M.; Jeremy, R.W.; Dyer, S.M.; Frank, T.L.; Becker, L.C. )

    1990-07-01

    Quantitation of myocardial perfusion with thallium-201 (201Tl) SPECT is limited by finite resolution and image noise. This study examined whether Wiener filtering could improve quantitation of the severity of myocardial perfusion deficits. In 19 anesthetized dogs, adjustable stenoses were placed on the left anterior descending (LAD, n = 12) or circumflex (LCx, n = 7) arteries. Thallium-201 SPECT images were acquired during maximal coronary vasodilation with dipyridamole, and simultaneous measurements of myocardial blood flow were made with microspheres. The relationship between SPECT and microsphere flow deficits in the LAD region was significantly better (p less than 0.05) with Wiener filtering (Y = 0.90X + 0.03, r = 0.78) than with conventional Hanning filtering (Y = 0.66X + 0.34, r = 0.61). Similarly, in the LCx region the relationship between SPECT and microsphere perfusion deficits was better (p less than 0.01) with the Wiener filter (Y = 0.91X + 0.07, r = 0.66) than with the Hanning filter (Y = 0.36X + 0.50, r = 0.40). Wiener filtering improves quantitation of the severity of regional myocardial perfusion deficits, allowing better assessment of the functional significance of coronary artery stenoses.

  17. Fast washout of thallium-201 from area of myocardial infarction: possible artifact of background subtraction

    SciTech Connect

    Brown, K.A.; Benoit, L.; Clements, J.P.; Wackers, F.J.

    1987-06-01

    A recent report described a pattern of reverse redistribution on poststreptokinase /sup 201/Tl studies which was believed to be due to rapid washout of /sup 201/Tl from the infarct area related to reperfusion of the infarct vessel. We have also observed the phenomenon of rapid washout of /sup 201/Tl from the area of infarction in the absence of thrombolytic therapy. This study was undertaken to test the hypothesis that rapid washout of /sup 201/Tl from an area of infarction is an artifact of background subtraction usually employed in analysis of washout. A total of 61 patients with previous myocardial infarction who underwent cardiac catheterization and exercise /sup 201/Tl imaging were examined. Thallium-201 images were analyzed using a validated quantitative method employing interpolative background correction. Abnormally increased /sup 201/Tl washout was noted in 11 infarct segments in 10 (18%) patients. Infarct segments with rapid washout had significantly less initial uptake, and more severe associated wall motion abnormalities than infarct segments with normal washout. When quantitative analysis was repeated without background subtraction, no segments with rapid washout were observed. A phantom model was constructed to further test our hypothesis. The frequency of observed rapid washout was directly related to the severity of the initial defect and was entirely dependent upon utilizing background correction during the quantitative analysis. Our study suggests that rapid washout of /sup 201/Tl in an area of previous infarction reflects an artifact of background subtraction involved with standard quantitative analysis.

  18. 201Tl heart-liver radioactivity uptake ratio and prediction of decompensation in patients with cirrhosis.

    PubMed

    Lee, Min-Ho; Tae, Hae-Jin; Jun, Dae-Won; Ryu, Seong-Eon; Choi, Yun-Young; Kwak, Min-Jeong; Kang, Ju-Seop

    2013-03-01

    The present study aimed to determine the predictive value of the heart-liver uptake ratio (H/L ratio) of rectally administered (201)Tl scintigraphy for hepatic decompensation, which was conducted in 107 patients with cirrhosis. We retrospectively assessed the predictive value of a noninvasive parameter, H/L ratio, for decompensation during a median follow-up period of 45.4 months using follow-up data from 1996 through 2008 for 107 patients with compensated cirrhosis. Logistic regression analysis and odds ratio estimates were used to estimate independent value of the H/L ratio on the risk of decompensation with 95% confidence intervals. At first visit, all subjects were confirmed as patients with compensated cirrhosis, 39 by liver biopsy and 68 by standard laboratory and radiological criteria. At end of the evaluation time, 81 patients remained compensated, whereas 26 patients decompensated as evidenced by ascites in 23, hepatic encephalopathy in 8, and variceal bleeding in 1 patient. First-visit parameters except bilirubin level, alanine aminotransferase (ALT), and H/L ratio and last visit parameters except ALT and aspartate aminotransferase-ALT ratio were significantly different between the 2 groups as ascertained by Wilcoxon rank sum test (P < 0.05). Among those parameters, we found that the last visit H/L ratio was a strongly reliable predictor of decompensation with an odds ratio estimates of 14.443, area under the receiver operating characteristic curve of 0.825, cutoff of 0.4, sensitivity of 73.1 %, and specificity of 71.6%. This evidence indicates that in patients with compensated cirrhosis, an increased H/L ratio at follow-up may be a useful predictive parameter showing a high risk of progression to a decompensated state.

  19. Usefulness of the Chang attenuation correction method with use of a CT-based μ map by FBP reconstruction in (201)Tl SPECT-MPI.

    PubMed

    Nakamura, Yuya; Tomiguchi, Seiji

    2015-06-01

    Attenuation correction (AC) on nuclear images of non-uniform domains is generally performed by a change of the computed tomography (CT) values to μ values, which are then inserted as components into the detection probability of iterative reconstruction techniques (OS-EM Iterative AC). We established an AC technique which uses a CT μ map based on the Chang AC. Our purpose in this study was to confirm the appropriateness of the Chang AC with the OS-EM and the FBP method (OS-EM Chang AC and FBP Chang AC) by evaluating the results obtained in a phantom and clinical study for (201)Tl single-photon emission-computed tomography-myocardial perfusion imaging (SPECT-MPI). Myocardial phantom study and retrospective clinical study were performed. Evaluations for image quality (uniformity and contrast) and image quantitative values [accurate left ventricular (LV) volume and radioactivity] were performed for both studies. FBP Chang AC showed good image uniformity and proper contrast in phantom and clinical study. Accurate LV volume and radioactivity in the myocardium were also obtained by the phantom study. On the other hand, the number of iterations influenced the image quality both in OS-EM Iterative AC and OS-EM Chang AC in the phantom study. Different numbers of iterations were necessary for obtaining good contrast ratio in each of the anterior and inferior wall, and accurate LV volume. The number of iterations influences the image quality and quantitative values on OS-EM Iterative Chang AC and OS-EM Chang AC images. In addition, it is difficult to set an appropriate number of iterations for the iterative reconstruction of these images in phantom and clinical studies. Therefore, FBP Chang AC is considered to be clinically useful.

  20. Voxel-based analysis of (201)Tl SPECT for grading and diagnostic accuracy of gliomas: comparison with ROI analysis.

    PubMed

    Kuwako, Tomoyuki; Mizumura, Sunao; Murakami, Ryusuke; Yoshida, Tamiko; Shiiba, Masato; Sato, Hidetaka; Fukushima, Yoshimitsu; Teramoto, Akira; Kumita, Shin-Ichiro

    2013-07-01

    The aim of this retrospective study was to assess the utility of a voxel-based analysis (VBA) method for (201)Tl SPECT in glioma, compared to conventional ROI analysis. We recruited 24 patients with glioma (high-grade 15; low-grade 9), for whom pre-operative (201)Tl SPECT and MRI were performed. SPECT images were coregistered with MRI. The uptake ratio (UR) images of tumor to contralateral normal tissue were measured on early and delayed images, and the (201)Tl retention index (RI) map was calculated from the early and delayed uptake ratio maps. In the ROI analysis, tumors were traced on a UR map, and the mean and maximal uptake ratio values on the early images were, respectively, defined as the mean and maximal UR. The mean and maximal RI values (mean and maximal RI) were calculated by division of the mean and maximal UR, respectively, on the delayed image by the mean and maximal UR on the early image. For the RI map calculated voxel by voxel, the maximal RI value was defined as VBA-RI. We evaluated sensitivity and accuracy of differential analysis with the mean and maximal UR, RI, and VBA-RI. The high- and low-grade groups showed no significant difference in mean and maximal RI (0.98 ± 0.12 vs. 1.05 ± 0.09 and 0.98 ± 0.18 vs. 1.05 ± 0.14, respectively). The AUC and accuracy of the mean and maximal RI were 0.681 and 66.7 %, and 0.622 and 62.5 %, respectively. In contrast, VBA-RI was higher in high-grade than in low-grade glioma (1.69 ± 0.27 vs. 0.68 ± 0.66, p < 0.001). The AUC and accuracy of VBA-RI were 0.963 and 95.8 %, which are higher than those obtained for mean (p < 0.05) and maximal RI (p < 0.01). There was no significant difference in ROC between the VBA-RI and the mean UR (0.911, p = 0.456) and maximal UR (0.933, p = 0.639); however, the AUC, sensitivity, and diagnostic accuracy of VBA-RI were all higher than those of the mean and maximal UR. The voxel-based analysis method of (201)Tl SPECT may improve diagnostic performance for gliomas, compared

  1. Assessment of resistance to paclitaxel of murine tumors by (99m)Tc-MIBI/(201)Tl dual-radionuclide imaging.

    PubMed

    Oriuchi, N; Jibu, T; Milas, L; Choe, J; Kuang, L; Kim, E E; Hunter, N R; Wallace, S; Podoloff, D A

    2000-02-01

    This study investigated P-glycoprotein (Pgp) expression by murine tumors with and without resistance to paclitaxel and the role of (99m)Tc-2-methoxyisobutylisonitrile (MIBI)/(201)Tl imaging in predicting the effect of paclitaxel. Antitumor effect of paclitaxel and biodistribution of the radiopharmaceuticals were evaluated in mice bearing four tumor types. Pgp expression did not correlate with the antitumor efficacy of paclitaxel. Although the absolute uptake of (99m)Tc-MIBI did not correlate with Pgp expression, (99m)Tc-MIBI could predict paclitaxel sensitivity by its higher uptake.

  2. Thallium-201 is comparable to technetium-99m-sestamibi for estimating cardiac function in patients with abnormal myocardial perfusion imaging.

    PubMed

    Wu, Ming-Che; Tsai, Cheng-Ting; Lin, Hui-Chun; Sun, Fang-Ju; Lin, Ku-Hung

    2015-11-01

    We analyzed the left-ventricular functional data obtained by cardiac-gated single-photon emission computed tomography myocardial perfusion imaging (MPI) with thallium-201 (Tl-201) and technetium-99m-sestamibi (MIBI) protocols in different groups of patients, and compared the data between Tl-201 and MIBI. Two hundred and seventy-two patients undergoing dipyridamole stress/redistribution Tl-201 MPI and 563 patients undergoing 1-day rest/dipyridamole stress MIBI MPI were included. Higher mean stress ejection fraction (EF), rest EF, and change in EF (ΔEF) were noticed in the normal MPI groups by both Tl-201 and MIBI protocols. Higher mean EF was observed in the females with normal MPI results despite their higher mean age. Comparisons between the Tl-201 and MIBI groups suggested a significant difference in all functional parameters, except for the rest end diastolic volume/end systolic volume and ΔEF between groups with negative MPI results. For the positive MPI groups, there was no significant difference in all parameters, except for the change in end diastolic volume and change in end systolic volume after stress between both protocols. The Tl-201 provides comparable left-ventricular functional data to MIBI cardiac-gated single-photon emission computed tomography in patients with positive MPI results, and may therefore be undertaken routinely for incremental functional information that is especially valuable to this patient group. Copyright © 2015. Published by Elsevier Taiwan.

  3. Myocardial uptake and washout kinetics of T1-201 with the VEX (vasodilator plus exercise) test: contribution of stress mode components and coronary stenosis severity.

    PubMed

    Hurwitz, G A; MacDonald, A C; Weingert, M E; Hessian, R C; Finnie, K J; St Clement, G; Powe, J E

    1996-07-01

    To assess the vasodilator plus exercise (VEX) test as an adjunct to myocardial perfusion imaging with respect to the accuracy of kinetics of thallium-201 (Tl-201) and other indicators of ischemia. A nuclear medicine laboratory in which patients referred for myocardial scintigraphy are triaged to undergo the stress component with symptom-limited bicycle exercise, dipyridamole or VEX as appropriate. Cases having correlating scintigraphy and angiography (n = 425) were selected retrospectively. Immediate poststress and redistribution images were quantified using a circumferential profile analysis with interpolative background subtraction. For each of nine sectors on the left anterior oblique image, multivariate analyses were performed, comparing the relative uptake and net washout of Tl-201 to the exercise workload attained, use of dipyridamole, time to redistribution, gender, and the angiographic presence and severity of stenoses at five key sites. Washout values standardized according to gender, exercise level and time to redistribution, were compared with relative uptake profiles and ST depression using receiver operating curves. For each sector, a significant contribution to Tl-201 washout was made by the exercise level (P < 0.001) and by at least one site of stenosis (P < 0.0001), but not by use of dipyridamole (P > 0.5); female gender was associated with increased washout (P < 0.01) except for the three lateral sectors. For each stress modality, standardized washout performed better than ST depression but not as well as relative uptake profiles in detecting coronary artery disease. For combined pharmacological-exercise stress, quantitative uptake profiles may assist in confirming subjective scan interpretation; washout profiles, even when standardized for gender and stress level, are suboptimal for confirming defect reversibility.

  4. Echocardiography versus (201)Tl semi-quantitative gated single photon emission tomography for the evaluation of cardiac disease associated with late stage Duchenne muscular dystrophy.

    PubMed

    Fujita, Atsushi; Arahata, Hajime; Sugawara, Miwa; Watanabe, Akihiro; Kawano, Yuji; Sasagasako, Naokazu; Fujii, Naoki

    2016-01-01

    In Duchenne muscular dystrophy (DMD) patients cardiac abnormalities are often detected. In adult DMD patients cardiac disease (CD) is a cause of death which increases by age and is related to respiratory dysfunction. Studies have demonstrated that CD in early DMD can be detected by echocardiography (EC) or semi-quantitative gated single photon emission tomography ((201)Tl SQGS), and the accuracy of these two tests is similar. As the disease advances, evaluation of CD by EC becomes difficult due to thoracic deformity and scoliosis. We compared (201)Tl SQGS and EC in the evaluation of cardiac function in late stage DMD, based on the ejection fraction (EF) value calculated by both tests. Twenty-three males with late stage DMD, 12 to 35 years of age (22.2±7.5), were studied by (201)Tl SQGS and EC. The mean EF value by (201)Tl SQGS was 60.8%±14.1%, which differed from that obtained by EC (52.7%±9.8%, P=0.003). Eleven patients less than 20 years old did not demonstrate a significant difference between the two tests (P=0.06), however, 12 patients over 20 years of age had significantly different results between tests (P=0.002). Although our patients were few we indicated that in DMD patients, aged older than 20 years, at an advanced stage of the disease, the EF values calculated by EC were lower than those by (201)Tl SQGS possibly due to thoracic deformity.

  5. Dynamic, equilibrium and human studies of adsorption of 201Tl by Prussian blue.

    PubMed

    Bhardwaj, Nidhi; Bhatnagar, Aseem; Pathak, D P; Singh, A K

    2006-03-01

    Prussian blue is the recommended but infrequently required antidote for radiocesium and thallium chemical poisoning. Conceivably, its most frequent application will be the decontamination of radiothallium (thallous chloride) from human body following myocardial scintigraphy. Dosage schedule and physicochemical parameters of interaction with radiothallium, however, need to be defined, as the known data is inadequate on this account. The objective of the present study is to create physiologically relevant and mathematically rigorous data on interaction of Prussian blue with Tl, to estimate dosage schedule of Prussian blue suitable for myocardial scintigraphy, and to perform preliminary human studies to evaluate the efficacy of the antidote in reducing the considerable radiation burden imparted by this radiotracer. Adsorption efficacy of Prussian blue for radiothallium was found to be more than 95% at basic (intestinal) pH even at low concentrations and in presence of the physiological cations, potassium and sodium. Isotherm analysis and derivations using Langmuir, Bajpai, Lagergreen, and Freundlich equations suggest a favorable adsorption of Tl on Prussian blue with qmax being 5,000 MBq g. Based on these findings and clinical considerations, particularly preferential gall bladder excretion and enterohepatic recycling of radioactive thallous chloride, a dose of 100 mg Prussian blue with every major meal for 3 days was considered adequate for the purpose. Our experience with the first two patients (serving as their own self-controls) suggests that Prussian blue therapy is a safe and effective method to significantly reduce radiation burden imparted by thallium myocardial scintigraphy.

  6. KEY COMPARISON: BIPM comparison BIPM.RI(II)-K1.Tl-201 of activity measurements of the radionuclide 201Tl

    NASA Astrophysics Data System (ADS)

    Ratel, G.; Michotte, C.

    2004-01-01

    Since 1979, six national metrology institutes (NMI) and another laboratory have submitted 16 samples of known activity of 201Tl to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Tl-201. The activities ranged from about 3.5 MBq to 207 MBq. The degrees of equivalence between each equivalent activity measured in the SIR and the key comparison reference value (KCRV) have been calculated and the results are given in the form of a matrix for six NMIs. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by Section II of the Consultative Committee for Ionizing Radiation (CCRI(II)), according to the provisions of the Mutual Recognition Arrangement (MRA).

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

    SciTech Connect

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

    2004-03-01

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

  8. Assessment of coronary ischaemia by myocardial perfusion dipyridamole stress technetium-99 m tetrofosmin, single-photon emission computed tomography, and coronary angiography in children with Kawasaki disease: pre- and post-coronary bypass grafting.

    PubMed

    Mostafa, Mostafa S; Sayed, Ashraf O; Al Said, Yasser M

    2015-06-01

    Coronary artery lesions in Kawasaki disease invasively assessed by coronary angiography. Evaluation of myocardial perfusion by single-photon emission computed tomography may identify the haemodynamic significance of coronary lesions. To evaluate diagnostic accuracy of dipyridamole stress technetium-99 m tetrofosmin, single-photon emission computed tomography as a possible alternative to invasive coronary angiography for detection and follow-up of myocardial ischaemia in patients with Kawasaki disease, and pre- and post-coronary bypass grafting. Coronary angiography and single-photon emission computed tomography were performed on 21 patients who were classified into three groups - group I (stenosis), group II (giant aneurysms), and group III (small aneurysms). Of the 21 patients, 16 (groups I and II) patients with myocardial perfusion defects, who underwent coronary bypass grafting, were followed up with single-photon emission computed tomography. In group I, all patients had significant coronary stenosis and 100% of them had perfusion defects in the anterior and septal walls. In group II, all patients had giant aneurysms and 83% of them had inferior and inferolateral perfusion defects. In group III, all patients had small aneurysms and 100% of them had normal perfusion. Pre-coronary bypass grafting myocardial ischaemic defects disappeared in all patients after surgery. Sensitivity, specificity, and accuracy of single-photon emission computed tomography were 94, 100, and 95%, respectively. Technetium-99 m tetrofosmin single-photon emission computed tomography can be applied as an accurate non-invasive diagnostic technique for detecting myocardial perfusion defects with coronary artery lesions, and to show improved or even normalised perfusion of the myocardium in patients after surgical revascularisation.

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

    SciTech Connect

    Forman, M.B.; Sandler, M.P.; Sacks, G.A.; Kronenberg, M.W.; Powers, T.A.

    1983-03-01

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

  10. Dielectric properties and charge transfer in (TlInSe2)0.1(TlGaTe2)0.9 for the DC and AC current

    NASA Astrophysics Data System (ADS)

    Mustafaeva, S. N.; Asadov, M. M.; Dzhabbarov, A. I.

    2014-06-01

    The experimental results of studying the temperature and frequency dependences of dc and ac conductivity as well as the dispersion of dielectric coefficients of the grown single crystals of the (TlInSe2)0.1(TlGaTe2)0.9 solid solution are presented. The nature of dielectric losses and the hopping charge transfer mechanism have been established, and parameters of localized states, such as the density of states near the Fermi level and their spread, the average time and the hopping length of charge carriers, and the concentration of deep traps responsible for dc and ac conductivity, have been evaluated.

  11. Imaging considerations for a technetium-99m myocardial perfusion agent

    SciTech Connect

    English, R.J.; Jones, A.G.; Davison, A.; Lister-James, J.; Campbell, S.; Holman, B.L.

    1986-03-01

    Myocardial perfusion imaging with /sup 201/Tl chloride suffers from a number of physical, geometric, and dosimetric constraints that could be diminished if an agent labeled with /sup 99m/Tc were available. The cationic complex /sup 99m/Tc hexakis-(t-butylisonitrile)technetium(I) ((/sup 99m/Tc)TBI) has been shown to concentrate in the myocardial tissue of both animals and humans, with preliminary clinical studies demonstrating a number of technical attributes not possible with /sup 201/Tl. Technetium-99m-TBI is a promising myocardial imaging agent that may permit high quality planar, gated, and tomographic imaging of both myocardial ischemia and infarction with reduced imaging times and improved resolution.

  12. Using adaptive neuro-fuzzy inference system technique for crosstalk correction in simultaneous 99mTc/201Tl SPECT imaging: A Monte Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Heidary, Saeed; Setayeshi, Saeed

    2015-01-01

    This work presents a simulation based study by Monte Carlo which uses two adaptive neuro-fuzzy inference systems (ANFIS) for cross talk compensation of simultaneous 99mTc/201Tl dual-radioisotope SPECT imaging. We have compared two neuro-fuzzy systems based on fuzzy c-means (FCM) and subtractive (SUB) clustering. Our approach incorporates eight energy-windows image acquisition from 28 keV to 156 keV and two main photo peaks of 201Tl (77±10% keV) and 99mTc (140±10% keV). The Geant4 application in emission tomography (GATE) is used as a Monte Carlo simulator for three cylindrical and a NURBS Based Cardiac Torso (NCAT) phantom study. Three separate acquisitions including two single-isotopes and one dual isotope were performed in this study. Cross talk and scatter corrected projections are reconstructed by an iterative ordered subsets expectation maximization (OSEM) algorithm which models the non-uniform attenuation in the projection/back-projection. ANFIS-FCM/SUB structures are tuned to create three to sixteen fuzzy rules for modeling the photon cross-talk of the two radioisotopes. Applying seven to nine fuzzy rules leads to a total improvement of the contrast and the bias comparatively. It is found that there is an out performance for the ANFIS-FCM due to its acceleration and accurate results.

  13. Thallium 201 Exercise Scintigraphy for Detection of Multivessel Coronary Artery Disease After Transmural Myocardial Infarction

    PubMed Central

    Ahmadpour, Hedayatolah; Siegel, Michael E.; Colletti, Patrick; Haywood, L. Julian

    1984-01-01

    Fifty patients with prior transmural myocardial infarction were studied with cardiac catheterization, coronary angiography, and thallium 201 exercise perfusion scintigraphy. Obstructive coronary disease involved two or three vessels in 37 patients. The sensitivity of a positive electrocardiographic test during exercise for detecting multivessel coronary disease was only 40 percent (15/37), and the sensitivity of a reversible defect on 201Tl perfusion scintigraphy was 48 percent (18/37). The combination of exercise testing and 201Tl scintigraphy detected multivessel coronary disease in 75 percent (28/37) (P < .05). New perfusion defects occurred in 61 percent (13/21) of patients with inferior myocardial infarction and multivessel coronary disease whereas it occurred in only 35 percent (5/14) of patients with prior anterior infarction and multivessel coronary disease (P < .05). 201Tl exercise perfusion scintigraphy appears to be more sensitive for detecting significant multivessel coronary disease in the presence of previous inferior infarction compared with previous anterior infarction. Combined graded exercise testing and 201Tl perfusion scintigraphy can reliably detect the presence of significant multivessel coronary disease after transmural myocardial infarction. ImagesFigure 3 PMID:6512876

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

    PubMed

    Onishi, Takayuki; Kobayashi, Isshi; Onishi, Yuko; Kawashima, Tomoyuki; Muramoto, Hirotaka; Nakamura, Hiroaki; Nagata, Yasutoshi; Umezawa, Shigeo; Niwa, Akihiro

    2010-11-01

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

  15. The additive value of transient left ventricular dilation using two-day dipyridamole 99mTc-MIBI SPET for screening coronary artery disease in patients with otherwise normal myocardial perfusion: a comparison between diabetic and non-diabetic cases.

    PubMed

    Fallahi, Babak; Beiki, Davood; Fard-Esfahani, Armaghan; Akbarpour, Saeed; Abolhassani, Arash; Kakhki, Vahid Reza Dabbagh; Eftekhari, Mohammad

    2010-01-01

    The prognostic value of transient ischemic dilation (TID) has been previously confirmed; however, its clinical significance for screening coronary artery disease (CAD) with balanced ischemia, as a cause of false negative myocardial perfusion imaging (MPI), is unclear. The goal of this study was to determine the additive diagnostic value of TID ratio for screening CAD in separate subgroups of diabetic and non-diabetics with normal perfusion. Eighty six patients with intermediate probability of CAD who had TID more than one in the presence of otherwise normal MPI using two-day technetium-99m methoxy isobutyl isonitrile ((99m)Tc-MIBI) single photon emission tomography (SPET) and dipyridamole stress (summed stress score<3 and left ventricular cavity<90 mL) were included in a prospective cohort study comprising two subgroups of diabetic and non- diabetic patients. An inclusive work-up with multiple noninvasive tests was performed for all patients from whom 38 cases subsequently underwent coronary angiography and 48 cases were categorized in the group with a very low likelihood (<5%) of CAD on the basis of clinical and paraclinical data over a minimum of 18 months follow up. The TID ratio was calculated using automated software. Gensini score (GS) as an indicator of severity/extent of stenosis and coronary artery index (CAI) as the number of arteries with more than 50% narrowing were calculated based on angiographic findings. Our results showed that only in diabetic patients with three-vessel disease, TID ratio (1.47 ± 0.23) differs significantly from the other groups of CAD. In diabetic patients subgroup, TID ratio correlated strongly with GS (r=0.957, P<0.0001) and CAI (r=0.659, P=0.001), while such correlations were not seen in the non-diabetic patients. On the basis of receiver operating characteristic curve analysis for screening CAD in diabetic patients with normal myocardial perfusion, 100% sensitivity and 77.8% normalcy rate were achieved when TID more than 1

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

    SciTech Connect

    Chouraqui, P.; Maddahi, J.; Henkin, R.; Karesh, S.M.; Galie, E.; Berman, D.S. )

    1991-03-01

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

  17. Use of thallium-201 redistribution scintigraphy in the preoperative differentiation of reversible and nonreversible myocardial asynergy.

    PubMed

    Rozanski, A; Berman, D S; Gray, R; Levy, R; Raymond, M; Maddahi, J; Pantaleo, N; Waxman, A D; Swan, H J; Matloff, J

    1981-11-01

    Thallium-201 (201Tl) redistribution scintigraphy might differentiate reversibly from nonreversibly asynergic myocardial segments and thus predict the response of these segments to coronary artery bypass grafting (CABG). To test this hypothesis, 25 consecutive patients undergoing CABG, preoperative stress-redistribution 201Tl scintigraphy, and both pre- and postoperative resting equilibrium radionuclide ventriculography were evaluated. For both types of scintigraphic study, each patient was imaged in the same three views. Because of the effects of CABG on septal motion, this region was considered separately. Postoperative improvement was noted in 54% of 72 preoperative asynergic segments. Improvement was common not only in hypokinetic but also in akinetic and dyskinetic segments, and occurred in a similar proportion of studies performed early (less than 2 weeks) or late (3-6 months) after CABG. Thallium-201 redistribution scintigraphy was highly predictive of the pattern of postoperative asynergy: The redistribution pattern was normal in 90% of segments with reversible asynergy and abnormal in 76% of segments with nonreversible asynergy. The presence or absence of pathologic Q waves was less sensitive in this differentiation. Septal segments, however, frequently demonstrated abnormal wall motion postoperatively, despite normal 201Tl redistribution scintigraphy. Resting left ventricular ejection fraction (LVEF) was generally unchanged postoperatively, but in some patients with multiple areas of reversible asynergy it did improve. Thus, 201Tl redistribution scintigraphy appears to reliably distinguish viable from nonviable asynergic myocardial zones, and predicts the response of these segments to CABG.

  18. Clinical assessment of myocardial viability using MRI during a constant infusion of Gd-DTPA.

    PubMed

    Pereira, R S; Wisenberg, G; Prato, F S; Yvorchuk, K

    2000-12-01

    This study assessed the accuracy and feasibility of magnetic resonance imaging (MRI) during a constant infusion of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) for the determination of myocardial viability in patients with recent acute myocardial infarction (AMI). Nine patients were studied within 10 days of AMI. Rest-redistribution 201Thallium (201Tl) single photon emission computed tomography (SPECT) was used as a gold standard for viability. Using MRI, regional perfusion was assessed using dynamic imaging during a bolus injection of Gd-DTPA and viability was assessed during a continuous infusion. Finally, cine MR images were acquired at baseline, during low-dose dobutamine infusion and after recovery. To assess viability, the left ventricle was divided into 16 segments and signal intensity in corresponding MRI and redistribution SPECT segments were compared. Wall thickening index (WTI) was determined at each step during the dobutamine study. The results revealed that in five patients, reduced perfusion in infarcted regions was observed qualitatively during dynamic first pass imaging. There was a significant inverse correlation between 201Tl uptake and MRI signal intensity, i.e. infarcted tissue (low 201Tl uptake) had increased MR signal intensity. Segments were separated into normal (201Tl uptake > 90%) and infarcted (< 601%). lnfarcted MRI segments had greater signal intensity than normal segments (179 +/- 50 vs. 102 +/- 14%; P < 0.0001). WTI in normal segments increased by 18 +/- 8.5% (P < 0.0001) from baseline to 10 microg/kg per min of dobutamine while infarcted tissue WTI decreased 2.8 +/- 7.2% (P = 0.17). Thus regions of myocardium that were infarcted as defined by reduced 201Tl uptake and absent contractile reserve showed greatly increased MRI signal intensity during a constant infusion of Gd-DTPA. The use of MRI during a constant infusion of Gd-DTPA is accurate and feasible for the determination of myocardial necrosis in a clinical setting.

  19. Assessment of myocardial viability in patients with myocardial infarction using twenty-four hour thallium-201 late redistribution imaging.

    PubMed

    Yang, Xiang-Jun; He, Yong-Ming; Zhang, Bin; Wu, Yi-Wei; Hui, Jie; Jiang, Ting-Bo; Song, Jian-Ping; Liu, Zhi-Hua; Jiang, Wen-Ping

    2006-01-01

    Rest thallium-201 (201Tl) myocardial perfusion imaging has been widely used for evaluation of myocardial ischemia/viability after myocardial infarction, but the ideal timing for imaging after injection to maximally estimate viability is not well established. Thirty-six patients with myocardial infarction underwent the initial, 3 h, and 24 h redistribution imaging after intravenous injection of 148-185 MBq 201Tl. The initial and 3 h images, the initial and 24 h images, and the 3 and 24 h images were compared double-blinded. Out of the 184 abnormal segments based on the initial imaging, 56 (30%) segments improved by at least 1 grade on the 3 h imaging while 78 (42%) segments improved by at least 1 grade on the 24 h imaging. The 24 h late imaging detected more viable myocardium than the 3 h imaging did, with a significant difference (chi2= 5.680, p = 0.017). There were 158 abnormal segments on the 3 h imaging, with average 28% (44) segments improved by at least 1 grade on the 24 h imaging. There were 128 initial abnormal segments with no improvement on the 3 h imaging. Out of these segments, the 24 h late redistribution imaging detected additional redistribution in 26 segments, taking up 20%. Twenty-four hour late 201Tl imaging will demonstrated additional redistribution in patients who have incompletely reversible defects on early redistribution imaging at 3h.

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

    SciTech Connect

    Willerson, J.T.

    1983-01-01

    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 /sup 201/Tl 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.

  1. [Myocardial perfusion scintigraphy 2012 in Germany. Results of the 6th Query].

    PubMed

    Lindner, O; Burchert, W; Schäfers, M; Schaefer, W

    2014-01-01

    The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 6th survey on myocardial perfusion scintigraphy (MPS) of the reporting year 2012. 278 questionnaires (177 private practices (PP), 78 hospitals (HO), 23 university hospitals (UH)) were evaluated. MPS of 105,941 patients were reported. 95% [2005 = 80%] of MPS studies were conducted with (99m)Tc perfusion radiopharmaceuticals and only 5% with 201Tl. 79% [2009 = 76%] of the MPS were performed in PP, 15% [2009 = 17%] in HO, and 6% [2009 = 7%] in UH. Data from 108 centres which participated in all surveys from 2005 to 2012 showed an increase in MPS numbers of 4.0% (PP +6.1%, HO +18.2%, UH -18.3%). 29% of all participants (27% of PP, 31% of HO, and 26% of UH) noticed no change and 26% of all participants (28% of PP, 17% of HO and 35% of UH) an increase in their MPS requests since the 2009 query. The type of stress was pharmacological in 39% [2009 = 31%]. Of these 61% with adenosine (39% with exercise), 22% with regadenoson (51% with exercise), 14% with dipyridamole (60% with exercise), and 3% with dobutamine. Gated SPECT was performed in 73% [2009 = 56%] of all rest, in 70% [2009 = 56%] of all stress and in 67% [47%] of all stress and rest MPS. Only 36% [2009 = 33%] of the centres performed a quantification of all their studies with scores, whereas 41% [2009 = 52%] did not apply any quantification. 60% [2009 = 49%] of the MPS were requested by ambulatory care cardiologists. The survey on MPS in Germany reveals a good conformity of imaging procedures with the current guideline. A positive development in MPS practice and referral can be stated. However, there is still some potential of MPS processing considering the quantitative perfusion analysis.

  2. Dipyridamole-thallium imaging: The lazy man's stress test

    SciTech Connect

    Leppo, J.A.

    1989-03-01

    Dipyridamole-thallium imaging is a relatively safe and accurate method to evaluate myocardial perfusion and stress. It is independent of patient motivation, exercise capacity and antianginal medications. Overall it detects coronary artery disease as well as exercise thallium and has already shown utility in prognostic determinations. The continued use of this test on a wide scale appears warranted and additional large scale experience needs to be critically evaluated. 53 references.

  3. Update on intravenous dipyridamole cardiac imaging in the assessment of ischemic heart disease

    SciTech Connect

    Younis, L.T.; Chaitman, B.R. )

    1990-01-01

    Intravenous dipyridamole is a relative selective coronary vasodilator which, when combined with thallium-201, provides a useful technique to assess myocardial perfusion. The intravenous dipyridamole is administered as an infusion at a rate of 0.14 mg/kg/min for 4 minutes. In the presence of significant coronary artery disease the increase of coronary blood flow is disproportionate between vessels with and without significant coronary lesions, providing the basis for detecting regional differences in flow using thallium-201. The test can be used alone or combined with low level exercise to increase test sensitivity. The test is safe when performed under medical supervision and when patient selection is done appropriately. Most of the side effects induced by dipyridamole infusion are well tolerated by patients and readily reversed with intravenous aminophylline and sublingual nitroglycerin. The average sensitivity and specificity of the dipyridamole thallium scintigraphy test from the major studies are 76% and 70%, respectively. The test is very useful in providing prognostic information in patients who are unable to exercise. A reversible thallium defect after dipyridamole infusion has been shown to be associated with significant mortality and morbidity in patients with documented or suspected coronary artery disease. The use of intravenous dipyridamole has been extended into other modalities of imaging, including 2-dimensional and Doppler echocardiography, to study functional changes in the left ventricular induced by the infusion of intravenous dipyridamole. 52 references.

  4. Aspirin and Extended-Release Dipyridamole

    MedlinePlus

    Do not substitute the individual components of aspirin and dipyridamole (Persantine) for the combination product of aspirin and extended-release dipyridamole.Keep all appointments with your doctor and the laboratory. Your doctor may ...

  5. Effects of heart rate on myocardial thallium-201 uptake and clearance

    SciTech Connect

    Nordrehaug, J.E.; Danielsen, R.; Vik-Mo, H. )

    1989-12-01

    The effects of heart rate on the myocardial uptake and clearance of {sup 201}Tl were studied prospectively in seven healthy men, mean age 43 +/- 7 (s.d.) yr. Initial and delayed (3 hr) thallium images were obtained in three views after three bicycle exercise tests: to maximal, 80% and 60% of predicted maximal heart rate. The mean of three views initial myocardial {sup 201}Tl uptake was higher at maximal than at both 80% and 60% of predicted maximal heart rate, being 81% (p less than 0.01) and 60% (p less than 0.01) of maximal activity, respectively. The myocardial activity in the delayed images was identical. There was a linear relationship between heart rate and the initial myocardial activity, r = 0.86 (p less than 0.001). The mean (range) {sup 201}Tl clearance was 58% (51-65), 47% (34-56), and 34% (22-49) (all differences p less than 0.01), respectively. Concordance among the three individual views in estimating clearance was best for the highest exercise level. There was a linear relationship between heart rate and clearance, r = 0.80 (p less than 0.001). Clearance was altered by only 1.67 x 10%/heart bpm (0.024 hr/heart beat). Clearance in the liver, spleen and lungs increased at submaximal exercise levels. Thus, a linear relationship between heart rate and clearance is the result of changes in the initial exercise myocardial {sup 201}Tl activity. Submaximal exercise may reduce reproducibility of clearance estimation, and the change of myocardial clearance with heart rate seems less than previously suggested.

  6. Decontamination of rat and human skin experimentally contaminated with (99m)Tc, (201)Tl and (131)I radionuclides using "Dermadecon" - a skin decontamination kit: an efficacy study.

    PubMed

    Nishad, Dhruv Kumar; Bhalla, Supriya; Khanna, Kushagra; Sharma, Braj Gaurav; Rawat, Harish Singh; Mittal, Gaurav; Bhatnagar, Aseem

    2017-05-03

    Radioactive skin contamination is one of the most likely risks which occurs after accidental or occupational radiological accidents apart from internal contamination. In such cases where the radioactive contamination has occurred, the person who is contaminated should be decontaminated as early as possible to reduce the damaging health effects of radiation. In the present study, the decontamination efficiency of a developed skin decontamination kit "dermadecon" has been evaluated in animal models and human subjects using gamma scintigraphy. Decontamination efficiency (percentage of the radioactive contaminant removed) was calculated for each radioactive isotope of the study and compared with control where general washing procedure was followed using liquid and soap. The effectiveness of the kit was calculated in animal model with respect to (99m)Tc-sodium-pertechnetate ((99m)TcO(4-)), (201)TlCl and (131)I and was found 92.84 ± 4.9%, 91.18 ± 3.23% and 94.67 ± 2.92%, respectively. Whereas, in case of human skin, the decontamination efficiency for (99m)TcO(4-) was observed to be 95.00 ± 3.21%. On the basis of findings from the study, it can be concluded that the decontamination agents of the used skin decontamination kit are effective for removal of localized radioactive contaminants from skin, as compared with normal decontamination using soap and water.

  7. Imaging of cocaine-induced global and regional myocardial ischemia

    SciTech Connect

    Oster, Z.H.; Som, P.; Wang, G.J.; Weber, D.A. )

    1991-08-01

    Severe and often fatal cardiac complications have been reported in cocaine users with narrowed coronary arteries caused by atherosclerosis as well as in young adults with normal coronaries. The authors have found that in normal dogs cocaine induces severe temporary hypoperfusion of the left ventricle as indicated by a significantly lower 201Tl concentration compared to the baseline state. The most significant decrease in uptake occurred 5 min after injection and was more pronounced in the septal and apical segments. Following intravenous administration of cocaine, instead of gradual disappearance of 201Tl from the left ventricle, there was continuous increase in 201Tl concentration in the left ventricle. These imaging experiments indicate that the deleterious effects of cocaine on the heart are probably due to spasm of the coronaries and decreased myocardial perfusion. Since spasm of the large subpericardial vessels does not seem to explain the magnitude of the increased coronary resistance and decreased coronary flow after cocaine as described in the literature, it is suggested that microvascular spasm of smaller vessels plays a major role in the temporary decrease in perfusion. The data may also suggest that severe temporary myocardial ischemia is probably the initiating factor for the cardiac complications induced by cocaine.

  8. Optimization of Acquisition Parameters for Simultaneous ,^^201rm Tl; and ,^^99rm mrm Tc Dual-Isotope Myocardial Imaging

    NASA Astrophysics Data System (ADS)

    Wang, Wen-Tung; Tsui, B. M. W.; Lalush, D. S.; Tocharoenchai, C.; Frey, E. C.

    2005-10-01

    In /sup 201/Tl//sup 99m/Tc dual-isotope simultaneous-acquisition (DISA) myocardial imaging, crosstalk due to Tc photons results in significant contamination of the Tl data. The objective of this work is to seek the acquisition parameters (i.e., energy window width and center) that have the optimal tradeoff between minimizing the crosstalk and maximizing the detection efficiency. The optimization criterion was based on maximizing an ideal observer signal-to-noise ratio (SNR) for the myocardial defect detection task using single-isotope and DISA projection images acquired from a torso phantom. For single-isotope images, the optimal energy windows (width/center: 26 keV/75 keV and 28 keV/165 keV for /sup 201/Tl, 30 keV/142 keV for /sup 99m/Tc) are wider than typical windows. For DISA imaging, the optimal windows varied with the /sup 99m/Tc to /sup 201/Tl activity ratio and are thus likely to depend on the uptake ratio in each patient. Using the optimal ratio 2.25-2.75 (148 MBq /sup 201/Tl and 333-407 MBq /sup 99m/Tc) with the corresponding optimal windows (22 keV/72 keV, 24 keV/167 keV, and 24 keV/140 keV) gives /sup 201/Tl images with substantially increased SNRs as well as /sup 99m/Tc images with SNRs same as those of 370 MBq /sup 99m/Tc-only images. However, without the addition of crosstalk compensation, the use of the optimal activity and energy windows alone is likely not sufficient to restore the DISA Tl SNR to that of Tl-only image.

  9. Pulmonary thallium-201 uptake following dipyridamole-exercise combination compared with single modality stress testing.

    PubMed

    Hurwitz, G A; O'Donoghue, J P; Powe, J E; Gravelle, D R; MacDonald, A C; Finnie, K J

    1992-02-01

    Angiographic and clinical determinants of pulmonary uptake of thallium-201 were assessed in a laboratory setting where supine bicycle exercise is used for stress testing in the absence of limiting pharmacologic or physical factors, and where symptom-limited exercise is added to intravenous dipyridamole infusion in other cases. Angiographic correlation was available in 400 patients, including 130 tested with exercise, 94 in whom only handgrip or abbreviated bicycle exercise could be used after dipyridamole, and 176 in whom intravenous dipyridamole was combined with a significant level of exercise. For each test mode, lung/myocardial ratios on the immediate image were highly correlated (p less than or equal to 0.001) with a score based on the number of critical coronary artery stenoses, with grading by contrast ventriculography, and with the number of stenosed (greater than or equal to 50%) arteries; relationships (p less than 0.05) to history of myocardial infarction and to gender were also present. Multiple regression analysis showed the critical stenosis score and ventricular dysfunction to be the only significant determinants. When dipyridamole based tests were compared with exercise, curves of receiver-operating characteristics showed a tendency to better diagnostic performance. When dipyridamole is incorporated in stress testing, the value of increased lung uptake as an ancillary diagnostic sign is similar to that established for exercise.

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

    PubMed

    Sasaki, Hideki; Shimizu, Mitsuyuki; Ogawa, Kazuhiko; Okazaki, Fumiko; Mizokami, Tsuneo; Kusaka, Masafumi; Uehara, Yoshiki; Taniguchi, Ikuo; Mochizuki, Seibu

    2007-04-01

    Stress thallium-201 (201Tl) myocardial scintigraphy can demonstrate perfusion abnormalities, especially in the septum in patients with complete left bundle branch block (CLBBB) even with angiographically normal coronary arteries. Differences in the images between exercise and pharmacological stress 201Tl myocardial scintigraphy were evaluated in patients with CLBBB and normal coronary arteries. Forty-five patients with CLBBB underwent exercise stress using treadmill or pharmacological (adenosine triphosphate) stress 201Tl myocardial scintigraphy from October 1997 to February 2003. Patients with myocardial diseases were excluded, such as cardiomyopathy and coronary artery diseases detected by echocardiography and/or cardiac catheterization. The myocardial segment was classified according to the American Heart Association style for coronary artery disease. Peak blood pressure levels and heart rates were significantly higher in the exercise stress group than in the pharmacological stress group (p < 0.001). The rate of defects in stress images was significantly higher in the exercise stress group (72.4%; 21/29 cases) than in the pharmacological stress group (18.8%; 3/16 cases) (p < 0.01). The rate of redistribution of observed defects in delayed images was 76.2% (16/21 cases) in the exercise stress group, and 0% (0/3 cases)in the pharmacological stress group (p < 0.01). The myocardial segments showing defects were different between the exercise stress group and the pharmacological stress group. Patients with CLBBB showed different frequencies of defects by stress 201Tl myocardial scintigraphy according to the stress method. Moreover, defects also occured in areas other than the septum. Blood pressure and heart rate were involved in the mechanisms of defects in left bundle branch block.

  11. Exercise thallium-201 myocardial scintigraphy in the follow-up of aortocoronary bypass graft surgery.

    PubMed Central

    Wainwright, R J; Brennand-Roper, D A; Maisey, M N; Sowton, E

    1980-01-01

    The predictive accuracy of exercise thallium-201 (201Tl) myocardial scintigraphy in the evaluation of aortocoronary bypass graft surgery was assessed in 48 patients undergoing angiographic investigation 15 months (mean time) after myocardial revascularisation. 201Tl scintigrams detected 61 out of 77 (79%) patent grafts but only 21 out of 42 (50%) occluded grafts, though, for grafts supplying non-infarcted myocardium, the predictive accuracy of graft patency and graft occlusion was 85 per cent and 81 per cent, respectively. Stress electrocardiography failed to detect 15 out of 21 patients with scintigraphic evidence of regional myocardial ischaemia. Residual ischaemia in the proximal left anterior descending coronary distribution was commonly detected in 201Tl scintigrams despite a patent, well-functioning left anterior descending graft to the distal coronary segment. Additional residual ischaemia attributable to ungrafted coronary disease was detected by scintigraphy in 32 (67%) patients and most commonly occurred in the distribution of the diagonal branch of the left anterior descending especially in the presence of a patent distal left anterior descending graft. Thus, independent grafts to the diagonal branch of the left anterior descending are recommended at the time of aortocoronary bypass graft surgery. Images PMID:6965585

  12. Risk stratification after myocardial infarction. Clinical overview

    SciTech Connect

    O'Rourke, R.A. )

    1991-09-01

    Many patients with an acute myocardial infarction can be stratified into subgroups that are at high risk for morbidity and mortality on the basis of clinical characteristics that indicate recurrent myocardial ischemia, persistent left ventricular dysfunction, and/or recurrent cardiac arrhythmias. In patients with uncomplicated myocardial infarction the assessment of symptoms, physical findings, and ECG changes during predischarge exercise testing often identifies patients at increased risk for further cardiac events. Because of the suboptimum sensitivity and specificity of the exercise ECG for detecting myocardial ischemia, myocardial perfusion imaging with 201Tl and/or assessment of global and segmental ventricular function by two-dimensional echocardiography or radionuclide cineangiography during or immediately after exercise are often added to the predischarge risk stratification.

  13. Segmental quantitative analysis of digital thallium-201 myocardial scintigrams in diagnosis of coronary artery disease. Comparison with rest and exercise electrocardiography and coronary arteriography.

    PubMed Central

    Wainwrwight, R J; Maisey, M N; Sowton, E

    1981-01-01

    One hundred and forty-nine patients with suspected ischaemic heart disease were evaluated by exercise thallium-201 myocardial scintigraphy (201Tl SMS), single lead exercise electrocardiography, and coronary arteriography. Myocardial distribution of tracer was assessed semi-quantitatively from digital 201Tl scintigrams and compared with tracer distribution in subjects with normal hearts. Fifty-two of 54 (96%) patients with normal coronary arteries had normal myocardial scintigrams whereas three patients had a positive ischaemic exercise electrocardiogram and were scan normal. Conversely, 36 of 95 (38%) patients with coronary artery disease had a positive ischaemic electrocardiogram compared with 94 of 95 (99%) patients who had a positive myocardial scintigram. Disease in specific coronary arteries could be deduced from the topography of myocardial tracer deficit. Disease was predicted correctly in 76 out of 80 (95%) of left anterior descending coronary stenoses, in 48 out of 64 (75%) of right coronary artery stenoses, and in 55 out of 64 (85%) of left circumflex coronary artery stenosis, despite the presence of infarcted myocardium in other territories. Similarly, single vessel disease was predicted correctly in 14 out of 17 (82%) patients and multiple vessel disease in 64 out of 77 (83%) patients. 201Tl SMS with segmental quantitative analysis is a highly sensitive and specific technique in the diagnosis of coronary artery disease and may be useful screening procedure to select patients for further investigation, particularly those with evidence of life-threatening severe left coronary artery disease. PMID:7317214

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

    SciTech Connect

    Tamaki, S.; Nakajima, H.; Murakami, T.

    1982-11-01

    Emission computed tomography (ECT) for thallium-201 (/sup 201/Tl) myocardial imaging was evaluated in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar /sup 201/Tl perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of /sup 201/Tl perfusion defects, the infarct area in planar images and the infarct volume in reconsturcted 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.

  15. Prognostic value of intravenous dipyridamole thallium imaging in patients with diabetes mellitus considered for renal transplantation

    SciTech Connect

    Camp, A.D.; Garvin, P.J.; Hoff, J.; Marsh, J.; Byers, S.L.; Chaitman, B.R. )

    1990-06-15

    Patients with diabetes and end-stage renal failure are known to have a high risk for cardiac morbidity and mortality associated with renal transplantation. The most efficient method to determine preoperative cardiac risk has not been established. To determine the effectiveness of intravenous dipyridamole thallium imaging in predicting cardiac events, 40 diabetic renal transplant candidates were studied preoperatively in a prospective trial. The study group consisted of 40 patients whose average age was 42 years (range 27 to 64); 34 (85%) were hypertensive and 21 (53%) were cigarette smokers. Cardiac history included chest pain in 6 patients and prior myocardial infarction in 3 patients. Dipyridamole thallium imaging showed reversible defects in 9 patients, fixed defects in 8 patients and normal scans in 23 patients. Dipyridamole thallium imaging was performed using 0.56 mg/kg of dipyridamole infused intravenously over 4 minutes. Cardiac events occurred only in patients with reversible thallium defects, of which there were 6. Of these 6 patients, 3 had cardiac events before transplantation and 3 had them in the early postoperative phase (within 6 weeks of surgery). Of 21 patients who underwent renal transplantation, 3 had cardiac events within 6 weeks of transplantation. The average duration of follow-up was 11 months (range 1 to 21). Thus, dipyridamole thallium imaging is an effective method of identifying renal transplant candidates likely to develop cardiac complications. Routine coronary angiography may not be necessary to screen all renal transplant candidates for coronary artery disease before surgery.

  16. Evaluation of the post-coronary artery bypass patient by myocardial perfusion scintigraphy and computed tomography

    SciTech Connect

    Engelstad, B.L.; Wagner, S.; Herfkens, R.; Botvinick, E.; Brundage, B.; Lipton, M.

    1983-09-01

    The clinical utility of /sup 201/Tl scintigraphy and of computed tomography for the noninvasive assessment of graft patency and regional myocardial perfusion was evaluated in 24 patients who had undergone aortocoronary bypass surgery. Perfusion defects on /sup 201/Tl scintigraphy (reversible or new, fixed) correlated (100% sensitivity, 78% specificity) with occlusion or stenosis of a graft or significant new native vessel disease. Graft occlusion was accurately demonstrated by dynamic computed tomography (100% sensitivity, 96% specificity) but did not uniformly correlate with regional perfusion. Perfusion defects in the distribution of patent grafts resulted from progressive native vessel disease or graft stenosis without complete occlusion. The absence of exercise-induced perfusion defects in regions of occluded grafts was attributed to suboptimal exercise, collateralization, or noncritical native vessel stenosis. The two studies provide complementary anatomic and physiologic information in the evaluation of the postbypass patient.

  17. Comparison of an adaptive neuro-fuzzy inference system and an artificial neural network in the cross-talk correction of simultaneous 99 m Tc / 201Tl SPECT imaging using a GATE Monte-Carlo simulation

    NASA Astrophysics Data System (ADS)

    Heidary, Saeed; Setayeshi, Saeed; Ghannadi-Maragheh, Mohammad

    2014-09-01

    The aim of this study is to compare the adaptive neuro-fuzzy inference system (ANFIS) and the artificial neural network (ANN) to estimate the cross-talk contamination of 99 m Tc / 201 Tl image acquisition in the 201 Tl energy window (77 ± 15% keV). GATE (Geant4 Application in Emission and Tomography) is employed due to its ability to simulate multiple radioactive sources concurrently. Two kinds of phantoms, including two digital and one physical phantom, are used. In the real and the simulation studies, data acquisition is carried out using eight energy windows. The ANN and the ANFIS are prepared in MATLAB, and the GATE results are used as a training data set. Three indications are evaluated and compared. The ANFIS method yields better outcomes for two indications (Spearman's rank correlation coefficient and contrast) and the two phantom results in each category. The maximum image biasing, which is the third indication, is found to be 6% more than that for the ANN.

  18. Clinical evaluation of 360 degrees and 180 degrees data sampling techniques for transaxial SPECT thallium-201 myocardial perfusion imaging.

    PubMed

    Go, R T; MacIntyre, W J; Houser, T S; Pantoja, M; O'Donnell, J K; Feiglin, D H; Sufka, B J; Underwood, D A; Meaney, T F

    1985-07-01

    The most serious controversy regarding the application of transaxial SPECT technology to 201Tl myocardial perfusion imaging is the choice between 360 degrees compared with 180 degrees data sampling techniques. The present study utilized the original 360 degrees sampled raw data of 25 patients who had both SPECT 201Tl myocardial perfusion imaging and coronary angio/ventriculography for back projection reprocessing to accomplish the 360 degrees/180 degrees comparison. The results show a high incidence, 36% (9/25), of false-positive segmental perfusion abnormality and a high incidence, 24% (6/25), of moderate to severe degree of image distortion with the 180 degrees data sampled reconstructed images. These were not observed in the 360 degrees data sampled reconstructed images. The above findings confirmed our previous preliminary conclusion that even though the 180 degrees data sampling technique has the advantage of providing improved image contrast and reduction in acquisition time it is not a reliable technique and should be abandoned. The 360 degrees data sampling is the technique of choice for transaxial SPECT 201Tl myocardial perfusion imaging.

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

    PubMed

    Maruyama, Yoshiaki; Masaki, Nobuyuki; Shimizu, Yuji; Honda, Norinari; Yoshimoto, Nobuo

    2009-11-01

    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 (123)iodine beta methyliodophenyl pentadecanoic acid ((123)I-BMIPP) and (201)thallium ((201)Tl). Subjects comprised 58 patients with first-time acute myocardial infarction who received reperfusion therapy and underwent RT-3DE and dual SPECT of (123)I-BMIPP and (201)Tl 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 (201)Tl uptake, (201)Tl washout, (123)I-BMIPP uptake, and (201)Tl-(123)I-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.

  20. Thallium-201 perfusion imaging with atrial pacing or dipyridamole stress testing for evaluation of cardiac risk prior to nonvascular surgery

    SciTech Connect

    Stratmann, H.G.; Mark, A.L.; Williams, G.A. )

    1990-09-01

    Preoperative assessment of cardiac risk using thallium-201 scintigraphy and atrial pacing (n = 42) or dipyridamole stress testing (n = 35) was performed in 77 patients (mean age 65 +/- 7 years), who subsequently underwent elective nonvascular surgery. All patients were at low cardiac risk by clinical criteria; none could perform exercise stress testing due to physical limitations. ST depression consistent with ischemia occurred in 11 patients during atrial pacing and in 1 patient during dipyridamole stress testing (p less than 0.01). Nine patients had reversible perfusion defects with atrial pacing, and 10 patients with dipyridamole stress testing; fixed defects were present in 15 and 8 patients, respectively. Only one patient (fixed perfusion defect with atrial pacing, left main disease on coronary angiography) underwent preoperative coronary revascularization. Two patients subsequently had postoperative cardiac events. One patient (reversible perfusion defect with dipyridamole stress testing) experienced sudden death after a nonvascular procedure, while a second patient (normal thallium images with dipyridamole testing) had a nonfatal myocardial infarction. In patients having atrial pacing or dipyridamole stress testing, thallium-201 scans that are normal or show only a fixed perfusion defect confirm a low risk of cardiac complications following nonvascular surgery. The presence of a reversible perfusion defect does not preclude a postoperative course free of cardiac complications in patients at low cardiac risk by clinical criteria.

  1. Dipyridamole-induced ST segment depression during thallium-201 imaging in patients with coronary artery disease: angiographic and hemodynamic determinants

    SciTech Connect

    Chambers, C.E.; Brown, K.A.

    1988-07-01

    To examine the angiographic and hemodynamic determinants of dipyridamole-induced ST segment depression in patients with coronary artery disease, 41 patients with angiographically documented coronary disease who underwent dipyridamole-thallium-201 myocardial scintigraphy were studied. Dipyridamole-induced ST depression occurred in 14 (34%) of the 41 patients. Stepwise multivariate logistic regression was performed to compare the predictive value of angiographic findings (good coronary collateral vessels, jeopardized collateral vessels, multivessel disease), hemodynamic changes (changes in heart rate, systolic pressure, diastolic pressure and rate-pressure product), thallium-201 results (perfusion defect, thallium-201 redistribution) and demographic data (age, gender, medications). Only the presence of good coronary collateral vessels (p less than 0.02) and increases in rate-pressure product after dipyridamole infusion (p less than 0.02) were significant multivariate predictors of dipyridamole-induced ST depression. Good collateral vessels were more common in the group with ST depression (11 (79%) of 14) than they were in the group without ST depression (6 (22%) of 27; p less than 0.001). Rate-pressure product increased 2,835 +/- 1,648 beats/min.mm Hg in the group with ST depression compared with 1,179 +/- 1,417 beats/min.mm Hg in patients without ST depression (p less than 0.005). In conclusion, dipyridamole-induced ST segment depression in patients with coronary artery disease appears to be related to 1) the presence of good coronary collateral vessels, which may act by facilitating coronary steal, and 2) increases in rate-pressure product, reflecting increased myocardial oxygen demand. These observations may explain the lack of prognostic value of dipyridamole-induced ST segment depression described in previous reports.

  2. Simultaneous low level treadmill exercise and intravenous dipyridamole stress thallium imaging

    SciTech Connect

    Casale, P.N.; Guiney, T.E.; Strauss, H.W.; Boucher, C.A.

    1988-10-01

    Intravenous dipyridamole-thallium imaging unmasks ischemia in patients unable to exercise adequately. However, some of these patients can perform limited exercise, which, if added, may provide useful information. Treadmill exercise combined with dipyridamole-thallium imaging was performed in 100 patients and results compared with those of 100 other blindly age- and sex-matched patients who received dipyridamole alone. Exercise began after completion of the dipyridamole infusion. Mean +/- 1 standard deviation peak heart rate (109 +/- 19 vs 83 +/- 12 beats/min, p less than 0.0001) and peak systolic and diastolic blood pressure (146 +/- 28/77 +/- 14 vs 125 +/- 24/68 +/- 11 mm Hg, p less than 0.0001) were higher in the exercise group compared with the nonexercise group. There was no difference in the occurrence of chest pain, but more patients in the exercise group developed ST-segment depression (26 vs 12%, p less than 0.0001). The exercise group had fewer noncardiac side effects (4 vs 12%, p less than 0.01) and a higher target (heart) to background (liver) count ratio (2.1 +/- 0.7 vs 1.2 +/- 0.3; p less than 0.01), due to fewer liver counts. There were no deaths, myocardial infarctions or sustained arrhythmias in either group. Combined treadmill exercise and dipyridamole testing is safe, associated with fewer noncardiac side effects, a higher target to background ratio and a higher incidence of clinical electrocardiographic ischemia than dipyridamole alone. Therefore, it is recommended whenever possible.

  3. Usefulness of dipyridamole-thallium-201 perfusion scanning for distinguishing ischemic from nonischemic cardiomyopathy

    SciTech Connect

    Eichhorn, E.J.; Kosinski, E.J.; Lewis, S.M.; Hill, T.C.; Emond, L.H.; Leland, O.S.

    1988-11-01

    To determine noninvasively the etiology of left ventricular (LV) dysfunction, 22 patients with a diagnosis of cardiomyopathy determined via cardiac catheterization and 5 normal control subjects underwent radionuclide ventriculography and intravenous dipyridamole-thallium-201 perfusion scanning. Both ischemically and nonischemically induced LV dysfunction had comparable global LV ejection fractions (24 +/- 6 vs 23 +/- 8%, respectively) and extent of segmental wall motion abnormalities. Right ventricular ejection fraction was significantly better in the group with an ischemic etiology of LV dysfunction (41 +/- 26 vs 13 +/- 10%, p less than 0.005) but significant group overlap was present. However, computer-assisted analysis of dipyridamole-thallium-201 myocardial perfusion scanning demonstrated more homogeneous myocardial perfusion in idiopathic cardiomyopathy (mean perfusion defect 25 +/- 11 vs 6 +/- 6%, p less than 0.001) and successfully predicted the correct etiology of LV dysfunction in 20 of 22 (91%) patients.

  4. Prevalence and prognostic significance of exercise-induced silent myocardial ischemia detected by thallium scintigraphy and electrocardiography in asymptomatic volunteers

    SciTech Connect

    Fleg, J.L.; Gerstenblith, G.; Zonderman, A.B.; Becker, L.C.; Weisfeldt, M.L.; Costa, P.T. Jr.; Lakatta, E.G. )

    1990-02-01

    Although a silent ischemic electrocardiographic response to treadmill exercise in clinically healthy populations is associated with an increased likelihood of future coronary events (i.e., angina pectoris, myocardial infarction, or cardiac death), such a response has a low predictive value for future events because of the low prevalence of disease in asymptomatic populations. To examine whether detection of reduced regional perfusion by thallium scintigraphy improved the predictive value of exercise-induced ST segment depression, we performed maximal treadmill exercise electrocardiography (ECG) and thallium scintigraphy (201Tl) in 407 asymptomatic volunteers 40-96 years of age (mean = 60) from the Baltimore Longitudinal Study on Aging. The prevalence of exercise-induced silent ischemia, defined by concordant ST segment depression and a thallium perfusion defect, increased more than sevenfold from 2% in the fifth and sixth decades to 15% in the ninth decade. Over a mean follow-up period of 4.6 years, cardiac events developed in 9.8% of subjects and consisted of 20 cases of new angina pectoris, 13 myocardial infarctions, and seven deaths. Events occurred in 7% of individuals with both negative 201Tl and ECG, 8% of those with either test positive, and 48% of those in whom both tests were positive (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl result were independent predictors of coronary events. Furthermore, those with positive ECG and 201Tl had a 3.6-fold relative risk for subsequent coronary events, independent of conventional risk factors.

  5. Detection of right ventricular pressure overloading by thallium-201 myocardial scintigraphy. Results in 57 patients with chronic respiratory diseases

    SciTech Connect

    Weitzenblum, E.; Moyses, B.; Dickele, M.C.; Methlin, G.

    1984-02-01

    The diagnostic value of thallium 201 (/sup 201/Tl) myocardial imaging was studied in 57 patients with chronic respiratory diseases, most with COPD (n . 46), by comparing the results to hemodynamic findings. In healthy subjects, the right ventricle (RV) is not visualized; therefore, any recorded activity of the RV was considered as indicating RV hypertrophy due to RV pressure overloading (RVPO). RV activity was graded from 0 (no activity) to 3 (activity greater than or equal to that of the left ventricle). Patients were divided into three groups according to the level of the pulmonary artery mean pressure (PPA): PPA less than or equal to 20 mm Hg (no pulmonary arterial hypertension (PAH) ) . group 1, n . 20; PPA ranging from 21 to 30 mm Hg (mild to moderate PAH) . group 2, n . 20; PPA greater than 30 mm Hg (marked PAH) . group 3, n . 17. RV was visualized in 14 patients in group 3 (82 percent) and in 13 patients in group 2 (65 percent). For all patients with PAH (2 + 3) the sensitivity of /sup 201/Tl imaging for the diagnosis of RVPO was of 73 percent, higher than that of ECG and echocardiography (both 51 percent). The sensitivity of /sup 201/Tl, even if moderate (65 percent) was better than that of ECG (30 percent) or echo (40 percent) in patients with mild-to-moderate PAH (group 2). A high RV activity (grade 3) was observed in only three patients. The specificity of this method (obtained from results in group 1) was of 80 percent vs 89 percent for echo and 100 percent for ECG. These results suggest that 201Tl myocardial imaging is a rather sensitive method and could be of interest for the noninvasive diagnosis of RVPO in COPD patients.

  6. Quantitative comparison of thallium-201 scintigraphy after exercise and dipyridamole in coronary artery disease

    SciTech Connect

    Varma, S.K.; Watson, D.D.; Beller, G.A. )

    1989-10-15

    Data comparing myocardial thallium-201 imaging after exercise and intravenous dipyridamole infusion in the same patients are scarce. Accordingly, this study is a segment-by-segment quantitative analysis of regional uptake and washout of thallium-201 after dipyridamole (0.56 mg/kg) and symptom-limited exercise testing in 21 patients (ages 58 +/- 9.2 years) with chest pain studied 2.5 +/- 1.0 weeks apart. Thallium-201 activity in 9 myocardial segments was measured in initial and delayed anterior and 45 degree left anterior oblique views, producing 184 pairs of segments in the distribution of 63 coronary supply regions for direct comparison. The number of segments with normal thallium-201 uptake and the number of numerically significant defects were similar with exercise and dipyridamole (76 vs 73%, 24 vs 27%, respectively, difference not significant). A slightly higher proportion of redistribution defects was found after dipyridamole infusion compared to exercise (17 vs 10%, p less than 0.05). Agreement between 87% (165 of 189) of segment pairs was found when each was classified as either normal or abnormal. Although 24 of 189 segments were discordant, agreement was observed in 92% (61 of 63) of coronary supply regions determined to be normal (41 of 41) or abnormal (20 of 22). In 15 patients who underwent cardiac catheterization, exercise and dipyridamole-thallium-201 scintigraphy detected 61% (16 of 26) vs 61% (16 of 26) of stenoses greater than 50% (difference not significant) and 100% (19 of 19) vs 100% (19 of 19) (difference not significant) normal vessels, respectively.

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

    PubMed

    Katayama, Takuji; Ogata, Nobuhiko; Tsuruya, Yoshio

    2008-05-01

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

  8. Prognostic value of dipyridamole thallium scintigraphy for evaluation of ischemic heart disease

    SciTech Connect

    Hendel, R.C.; Layden, J.J.; Leppo, J.A. )

    1990-01-01

    Exercise testing alone or in combination with thallium scintigraphy has significant prognostic value. In contrast, dipyridamole thallium imaging is not dependent on patients achieving adequate levels of exercise, but no long-term prognostic studies have been reported. Accordingly, imaging results of 516 consecutive patients referred for dipyridamole thallium studies were correlated with subsequent cardiac events, death (n = 23) and myocardial infarction (n = 43) over a mean follow-up period of 21 months. Patients with a history of congestive heart failure, prior myocardial infarction, diabetes mellitus or abnormal scans were significantly more likely to have a cardiac event (p less than 0.03). With use of logistic regression analysis, an abnormal scan was an independent and significant predictor of subsequent myocardial infarction or cardiac death and increased the relative risk of any event more than threefold. The presence of redistribution on thallium scanning further increased the risk of a cardiac event. Survival analysis demonstrated a significant difference between patients with an abnormal or normal thallium scan over a 30 month period. In conclusion, dipyridamole thallium scintigraphy demonstrates prognostic value in a large unselected population and may be an adequate clinical alternative to physiologic exercise testing in the evaluation of coronary heart disease.

  9. Impaired Coronary Flow Reserve Is the Most Important Marker of Viable Myocardium in the Myocardial Segment-Based Analysis of Dual-Isotope Gated Myocardial Perfusion Single-Photon Emission Computed Tomography

    PubMed Central

    Lee, Won Woo; So, Young; Kim, Ki-Bong

    2014-01-01

    Objective The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), 201Tl perfusion status at rest, 201Tl 24 hours redistribution and systolic wall thickening of 99mTc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery. Materials and Methods A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 ± 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG. Results The left ventricular ejection fraction (LVEF) significantly increased from 37.8 ± 9.0% to 45.5 ± 12.3% (p < 0.001) in 22 patients who had a pre-CABG LVEF lower than 50%. Among 590 myocardial segments in the re-vascularized area, 115 showed abnormal wall motion before CABG and 73.9% (85 of 115) had wall motion improvement after CABG. In the univariate analysis (n = 115 segments), stress/rest reversibility (p < 0.001) and 201Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001). Conclusion Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG. PMID:24642696

  10. The comparison of 2-18F-2-deoxyglucose and 15-(ortho-123I-phenyl)-pentadecanoic acid uptake in persisting defects on thallium-201 tomography in myocardial infarction

    SciTech Connect

    Henrich, M.M.; Vester, E.; von der Lohe, E.; Herzog, H.; Simon, H.; Kuikka, J.T.; Feinendegen, L.E. )

    1991-07-01

    The myocardial uptake of glucose and fatty acids into 201Tl redistribution defects were studied in 32 patients with myocardial infarction by tomography using 2-18F-2-deoxyglucose (FDG) and 15-(ortho-123I-phenyl)-pentadecanoic acid (oPPA). A total of 1153 segments were analyzed, 408 (35%) of which showed a persistent thallium-defect in stress-redistribution images. Of the segments with a decreased 201Tl uptake in these redistribution tomograms, 50.5% had a decreased uptake of both FDG and oPPA; in 21.8% FDG as well as oPPA uptake was within normal range. Normal FDG uptake but decreased oPPA uptake was detected in 17.4%, whereas 10.3% of the segments had normal oPPA uptake but decreased FDG uptake (chi-square test, p less than 0.001). A significant correlation of FDG and oPPA uptake (r = 0.51) was found in the segments with persistent 201Tl defect. Thus, a substantial fraction of persistent thallium-defects after healed myocardial infarction exhibit FDG as well as oPPA uptake, probably due to residual fatty acid metabolism in partially ischemic regions.

  11. [Estimation of I-123 metaiodobenzylguanidine (MIBG) myocardial washout].

    PubMed

    Saito, T; Watanabe, N; Saitoh, T; Asakura, T; Kanke, M; Owada, K; Hoshi, K; Kimura, K; Maruyama, Y

    1990-11-01

    A crosstalk from I-123 to Tl-201 (Tl) window was 35 +/- 30% (mean +/- SD) and 30 +/- 10% in a myocardial phantom and the images of 6 patients respectively. However, the crosstalk from Tl to I-123 was approximately 1% in each. I-123 MIBG (MIBG) and Tl myocardial SPECT images were recorded in 3 normal volunteers (N), 10 patients with myocardial infarction (MI), and 4 with dilated cardiomyopathy (DCM). The MIBG and Tl imagings were performed on the other day to avoid the crosstalk. Myocardial washout rates (WR) of Tl and MIBG were derived from 15 min and 4 hour images. WR of Tl was approximately 36% in each group. On the other hand, WR of MIBG in DCM (52 +/- 7%) and MI (41 +/- 14%) groups were statistically higher than in N (24 +/- 7%) group. Thus WR of MIBG would be useful to detect abnormalities in adrenergic nervous system.

  12. Effects of modified pharmacologic stress approaches on hyperemic myocardial blood flow

    SciTech Connect

    Czernin, J.; Auerbach, M.; Sun, K.T.

    1995-04-01

    Pharmacologic stress testing with 0.56 mg/kg of intravenous dipyridamole is frequently used to noninvasively detect coronary artery disease (CAD). However, high-dose dipyridamole (0.80 mg/kg) or the combination of standard-dose dipyridamole (0.56 mg/kg) with the isometric handgrip maneuver might evoke a greater coronary hyperemic response. To evaluate the effect of modified pharmacologic stress tests, myocardial blood flow was quantified in 11 male subjects (mean age: 27 {plus_minus} 7 yr) during standard-dose dipyridamole (0.56 mg/kg), high-dose dipyridamole (0.80 mg/kg) and standard-dose dipyridamole combined with the isometric handgrip exercise using dynamic PET and a two-compartment model for {sup 13}N-ammonia. Systolic blood pressure, heart rate and rate pressure product remained unchanged from standard to high-dose dipyridamole but increased with the addition of the isometric handgrip. Myocardial blood flow was unchanged from standard to high-dose dipyridamole but was lower with the addition of the isometric handgrip. The hyperemic response induced by standard-dose dipyridamole cannot be further enhanced by high-dose dipyridamole. The addition of the isometric handgrip exercise results in a modest, but significant decline in hyperemic blood flow possibly due to increased extravascular resistive forces or an increase in a mediated coronary vasoconstriction associated with exercise. 31 refs., 2 figs., 1 tab.

  13. Scintigraphic anatomy of coronary artery disease in digital thallium-201 myocardial images.

    PubMed Central

    Wainwright, R J

    1981-01-01

    One hundred and eight patients with single and multiple vessel coronary artery disease confirmed by arteriography were evaluated by exercise thallium-201 (201Tl) myocardial scintigraphy to determine the scintigraphic appearances of specific coronary stenoses. In general proximal stenoses caused more widespread, but not necessarily more severe, myocardial tracer deficit than distal stenoses. In particular, proximal dominant right coronary artery disease was specifically associated with extensive inferior wall tracer deficit in the anterior scintigram, whereas proximal left circumflex disease caused similar tracer depletion best visualised in the left lateral scintigram. A triad of uptake defects was caused by left anterior descending coronary artery disease: viz. apical tracer deficit (anterior view) in 71% lesions, septal tracer deficit (left anterior oblique view) in 83% of lesions, and anterolateral wall tracer deficit (left lateral projection) in 72% of lesions. The last defect has been termed a 'diagonal window' because it was associated with independent disease of the main diagonal branch of the left anterior descending coronary artery or with disease in the main left anterior descending artery situated proximal to this branch. Diagonal window tracer deficit was the most useful scintigraphic sign distinguishing proximal from distal disease in the left anterior descending coronary artery. False negative scintigraphic defects occurred more commonly in patients with triple vessel disease and in association with well-developed coronary collateral vessels. Certain scintigraphic patterns of 201Tl myocardial accumulation appear invaluable in the noninvasive localisation of stenoses within specific coronary arteries and thus may be useful in predicting life-threatening coronary artery disease which should be confirmed by definite coronary arteriography. The digital 201Tl myocardial scintigram also provides an independent functional guide to the interpretation of

  14. Platelet hyperaggregability, blood prostacyclin and dipyridamole.

    PubMed

    Solvay, H; Kahn, M; Cloarec, M; Van De Merckt, J; Sneppe, R; Schram, E; Fenollar, J V

    1986-03-01

    This study demonstrates the presence of PGI2 in blood and its influence on platelet retention tests, possibly by the intermediate of a releasing system in the columns, which is followed by a proximate recuperation on the erythrocyte sites after the passage. The presence of prostacyclin on the erythrocyte sites seems to depend upon the red cell deformability in relation to the good condition of their erythrocyte ATP reserve. The load of the erythrocyte sites increases with the daily dose of dipyridamole. The maximum load of the sites appears to be reached with a daily dose of dipyridamole 450 mg. Approximately 10% of the atherosclerosis patients who have been treated by dipyridamole keep their platelet hyperaggregability and their abnormally lowered prostacyclin level.

  15. KEY COMPARISON: Activity measurements of the radionuclide 201Tl for the LNE-LNHB, France, PTB, Germany and the NPL, UK in the ongoing comparison BIPM.RI(II)-K1.Tl-201

    NASA Astrophysics Data System (ADS)

    Ratel, G.; Michotte, C.; Moune, M.; Bobin, C.; Kossert, K.; Johansson, L.

    2008-01-01

    In 2005, the Laboratoire national de métrologie et essais-Laboratoire national Henri Becquerel (LNE-LNHB) and the Physikalisch-Technische Bundesanstalt (PTB) each submitted a sample of known activity of 201Tl to the International Reference System (SIR). In 2006, the National Physical Laboratory (NPL) submitted their first sample. The range of values of the activity submitted was between 2 MBq and 63 MBq. These key comparison results have been included in the re-evaluated key comparison reference value and replaced the previous results for France and Germany in the matrix of degrees of equivalence in the key comparison database that now contains seven results, identifier BIPM.RI(II)-K1.Tl-201. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  16. Effect of exercise supplementation on dipyridamole thallium-201 image quality

    SciTech Connect

    Stern, S.; Greenberg, I.D.; Corne, R. )

    1991-08-01

    To determine the effect of different types of exercise supplementation on dipyridamole thallium image quality, 78 patients were prospectively randomized to one of three protocols: dipyridamole infusion alone, dipyridamole supplemented with isometric handgrip, and dipyridamole with low-level treadmill exercise. Heart-to-lung, heart-to-liver, and heart-to-adjacent infradiaphragmatic activity ratios were generated from anterior images acquired immediately following the test. Additionally, heart-to-total infradiaphragmatic activity was graded semiquantitatively. Results showed a significantly higher ratio of heart to subdiaphragmatic activity in the treadmill group as compared with dipyridamole alone (p less than 0.001) and dipyridamole supplemented with isometric handgrip exercise (p less than 0.001). No significant difference was observed between patients receiving the dipyridamole infusion, and dipyridamole supplemented with isometric handgrip exercise. The authors conclude that low-level treadmill exercise supplementation of dipyridamole infusion is an effective means of improving image quality. Supplementation with isometric handgrip does not improve image quality over dipyridamole alone.

  17. Effects of CT-based attenuation correction of rat microSPECT images on relative myocardial perfusion and quantitative tracer uptake

    SciTech Connect

    Strydhorst, Jared H. Ruddy, Terrence D.; Wells, R. Glenn

    2015-04-15

    Purpose: Our goal in this work was to investigate the impact of CT-based attenuation correction on measurements of rat myocardial perfusion with {sup 99m}Tc and {sup 201}Tl single photon emission computed tomography (SPECT). Methods: Eight male Sprague-Dawley rats were injected with {sup 99m}Tc-tetrofosmin and scanned in a small animal pinhole SPECT/CT scanner. Scans were repeated weekly over a period of 5 weeks. Eight additional rats were injected with {sup 201}Tl and also scanned following a similar protocol. The images were reconstructed with and without attenuation correction, and the relative perfusion was analyzed with the commercial cardiac analysis software. The absolute uptake of {sup 99m}Tc in the heart was also quantified with and without attenuation correction. Results: For {sup 99m}Tc imaging, relative segmental perfusion changed by up to +2.1%/−1.8% as a result of attenuation correction. Relative changes of +3.6%/−1.0% were observed for the {sup 201}Tl images. Interscan and inter-rat reproducibilities of relative segmental perfusion were 2.7% and 3.9%, respectively, for the uncorrected {sup 99m}Tc scans, and 3.6% and 4.3%, respectively, for the {sup 201}Tl scans, and were not significantly affected by attenuation correction for either tracer. Attenuation correction also significantly increased the measured absolute uptake of tetrofosmin and significantly altered the relationship between the rat weight and tracer uptake. Conclusions: Our results show that attenuation correction has a small but statistically significant impact on the relative perfusion measurements in some segments of the heart and does not adversely affect reproducibility. Attenuation correction had a small but statistically significant impact on measured absolute tracer uptake.

  18. Usefulness of semiquantitative analysis of dipyridamole-thallium-201 redistribution for improving risk stratification before vascular surgery

    SciTech Connect

    Levinson, J.R.; Boucher, C.A.; Coley, C.M.; Guiney, T.E.; Strauss, H.W.; Eagle, K.A. )

    1990-08-15

    Preoperative dipyridamole-thallium-201 scanning is sensitive in identifying patients prone to ischemic cardiac complications after vascular surgery, but most patients with redistribution do not have an event after surgery. Therefore, its positive predictive value is limited. To determine which patients with thallium redistribution are at highest risk, dipyridamole-thallium-201 images were interpreted semiquantitatively. Sixty-two consecutive patients with redistribution on preoperative dipyridamole-thallium-201 planar imaging studies were identified. Each thallium scan was then analyzed independently by 2 observers for the number of myocardial segments out of 15, the number of thallium views out of 3 and the number of coronary artery territories with redistribution. Seventeen patients (27%) had postoperative ischemic events, including unstable angina pectoris, ischemic pulmonary edema, myocardial infarction and cardiac death. Thallium predictors of ischemic operative complications included thallium redistribution greater than or equal to 4 myocardial segments (p = 0.03), greater than or equal to 2 of the 3 planar views (p = 0.005) and greater than or equal to 2 coronary territories (p = 0.007). No patient with redistribution in only 1 view had an ischemic event (0 of 15). Thus, determining the extent of redistribution by dipyridamole-thallium-201 scanning improves risk stratification before vascular surgery. Patients with greater numbers of myocardial segments and greater numbers of coronary territories showing thallium-201 redistribution are at higher risk for ischemic cardiac complications. In contrast, when the extent of thallium redistribution is limited, there is a lower risk despite the presence of redistribution.

  19. Iterative deconvolution of simultaneous 99mTc and 201Tl projection data measured on a CdZnTe-based cardiac SPECT scanner

    NASA Astrophysics Data System (ADS)

    Kacperski, Krzysztof; Erlandsson, Kjell; Ben-Haim, Simona; Hutton, Brian F.

    2011-03-01

    We present a method of correcting self-scatter and crosstalk effects in simultaneous technetium-99m/thallium-201 stress/rest myocardial perfusion (single photon emission computed tomography) SPECT scans. The method, which is in essence a hybrid between the triple energy window method and scatter modelling, is based on a model of spatial and spectral distribution of projection counts in several selected energy windows. The parameters of the model are determined from measurements of thin rod sources in air when no in-object scatter or attenuation effects are present. The model equations are solved using the iterative maximum likelihood expectation maximization algorithm in the projection space to find estimates of the primary photopeak counts of both radionuclides. The method has been developed particularly for a novel dedicated cardiac camera based on CdZnTe pixellated detectors, although it can also be adapted to a conventional scintillator camera. The method has been validated in anthropomorphic phantom experiments. Significant improvement in defect contrast has been observed with only moderate increase in image noise. The application of the method to patient data is illustrated.

  20. Peritoneal fluid causing inferior attenuation on SPECT thallium-201 myocardial imaging in women

    SciTech Connect

    Rab, S.T.; Alazraki, N.P.; Guertler-Krawczynska, E.

    1988-11-01

    On SPECT thallium images, myocardial left ventricular (LV) anterior wall attenuation due to breast tissue is common in women. In contrast, in men, inferior wall counts are normally decreased compared to anterior counts. The purpose of this report is to describe cases of inferior wall attenuation of counts in women caused by peritoneal fluid, not myocardial disease. Twelve consecutive SPECT thallium myocardial studies performed in women on peritoneal dialysis, being evaluated for kidney transplant, were included in this study. For all studies, 3.5 mCi 201Tl were injected intravenously. Thirty-two images were acquired over 180 degrees (45 degrees RAO progressing to 45 degrees LPO) at 40 sec per stop. SPECT images were reviewed in short axis, horizontal long and vertical long axes. Data were also displayed in bullseye format with quantitative comparison to gender-matched normal files. Ten of 12 female patients studied had inferior wall defects on images, confirmed by bullseye display. All patients had approximately 2 liters of peritoneal fluid. Review of planar rotational views showed diaphragm elevation and fluid margin attenuations affecting left ventricular inferior wall. Thus, peritoneal fluid is a cause of inferior attenuation on 201Tl cardiac imaging.

  1. Lack of pharmacokinetic interaction between dipyridamole and zalcitabine in rats.

    PubMed

    Abobo, C V; Xian, Y

    1997-11-01

    Resistance usually manifests following long-term dideoxynucleoside therapy of HIV-1 infection. This period appears to coincide with reduced dosage regimens. Resistance that is associated with long-term monotherapy may, in part, be due to decreased intracellular drug concentrations. It has been reported that intracellular uptake of the dideoxynucleosides is enhanced by dipyridamole. Hence, dipyridamole may potentially be used to optimize the effects of zalcitabine in HIV-1 antiretroviral "cocktail". The purpose of this study was to characterize the pharmacokinetics of zalcitabine when administered alone and concomitantly with dipyridamole. Also, we determined, indirectly, whether dipyridamole modulated the intracellular uptake of zalcitabine. Rats were intravenously administered either zalcitabine 100 mg/kg alone or with dipyridamole 15 mg/kg. Except renal clearance (CIR), there were no statistically significant differences in the pharmacokinetic parameters including the steady-state volume of distribution and distribution coefficient. Zalcitabine plasma concentrations declined rapidly in a bi-exponential fashion, with a terminal half-life of 1.03 +/- 0.18 hr. alone versus 1.08 +/- 0.22 hr. with dipyridamole. The area under the concentration-time curve was not significantly different with or without dipyridamole. ClR, was 1.42 +/- 0.37 l/hr./kg for zalcitabine alone versus 1.09 +/- 0.28 l/hr./kg with dipyridamole. Our single dose study show that zalcitabine disposition kinetics were not significantly modulated by dipyridamole.

  2. Detection of coronary artery disease using MR imaging with dipyridamole infusion

    SciTech Connect

    Pennell, D.J.; Underwood, S.R.; Longmore, D.B. )

    1990-03-01

    Exercise testing in the magnetic resonance (MR) scanner is difficult because of space restriction and movement artefact, which limit its use in the investigation of patients with suspected coronary artery disease. Pharmacological stress, however, can be used as a substitute for exercise. Therefore, a patient with angina underwent MR ventricular wall motion studies before and after intravenous dipyridamole. Reversible abnormal regional contraction of the myocardium was demonstrated and correlated with a reversible perfusion defect on subsequent thallium myocardial perfusion imaging and a blocked artery at coronary angiography. A clinically useful investigative procedure may be developed.

  3. New Exercise-Dipyridamole Combined Test for Nuclear Cardiology in Insufficient Effort: Appropriate Diagnostic Sensitivity Keeping Exercise Prognosis

    PubMed Central

    Cortinas, Inés Vidal; Beretta, Mario; Alonso, Omar; Mut, Fernando

    2015-01-01

    Background Myocardial perfusion scintigraphy (MPS) in patients not reaching 85% of the maximum predicted heart rate (MPHR) has reduced sensitivity. Objectives In an attempt to maintain diagnostic sensitivity without losing functional exercise data, a new exercise and dipyridamole combined protocol (EDCP) was developed. Our aim was to evaluate the feasibility and safety of this protocol and to compare its diagnostic sensitivity against standard exercise and dipyridamole protocols. Methods In patients not reaching a sufficient exercise (SE) test and with no contraindications, 0.56 mg/kg of dipyridamole were IV administered over 1 minute simultaneously with exercise, followed by 99mTc-MIBI injection. Results Of 155 patients, 41 had MPS with EDCP, 47 had a SE test (≥ 85% MPHR) and 67 underwent the dipyridamole alone test (DIP). They all underwent coronary angiography within 3 months. The three stress methods for diagnosis of coronary lesions had their sensitivity compared. For stenosis ≥ 70%, EDCP yielded 97% sensitivity, SE 90% and DIP 95% (p = 0.43). For lesions ≥ 50%, the sensitivities were 94%, 88% and 95%, respectively (p = 0.35). Side effects of EDCP were present in only 12% of the patients, significantly less than with DIP (p < 0.001). Conclusions The proposed combined protocol is a valid and safe method that yields adequate diagnostic sensitivity, keeping exercise prognostic information in patients unable to reach target heart rate, with fewer side effects than the DIP. PMID:26039661

  4. Investigation of optimal acquisition time of myocardial perfusion scintigraphy using cardiac focusing-collimator

    NASA Astrophysics Data System (ADS)

    Niwa, Arisa; Abe, Shinji; Fujita, Naotoshi; Kono, Hidetaka; Odagawa, Tetsuro; Fujita, Yusuke; Tsuchiya, Saki; Kato, Katsuhiko

    2015-03-01

    Recently myocardial perfusion SPECT imaging acquired using the cardiac focusing-collimator (CF) has been developed in the field of nuclear cardiology. Previously we have investigated the basic characteristics of CF using physical phantoms. This study was aimed at determining the acquisition time for CF that enables to acquire the SPECT images equivalent to those acquired by the conventional method in 201TlCl myocardial perfusion SPECT. In this study, Siemens Symbia T6 was used by setting the torso phantom equipped with the cardiac, pulmonary, and hepatic components. 201TlCl solution were filled in the left ventricular (LV) myocardium and liver. Each of CF, the low energy high resolution collimator (LEHR), and the low medium energy general purpose collimator (LMEGP) was set on the SPECT equipment. Data acquisitions were made by regarding the center of the phantom as the center of the heart in CF at various acquisition times. Acquired data were reconstructed, and the polar maps were created from the reconstructed images. Coefficient of variation (CV) was calculated as the mean counts determined on the polar maps with their standard deviations. When CF was used, CV was lower at longer acquisition times. CV calculated from the polar maps acquired using CF at 2.83 min of acquisition time was equivalent to CV calculated from those acquired using LEHR in a 180°acquisition range at 20 min of acquisition time.

  5. Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery

    SciTech Connect

    Boucher, C.A.; Brewster, D.C.; Darling, R.C.; Okada, R.D.; Strauss, H.W.; Pohost, G.M.

    1985-02-14

    To evaluate the severity of coronary artery disease in patients with severe peripheral vascular disease requiring surgery, preoperative dipyridamole-thallium imaging was performed in 54 stable patients with suspected coronary artery disease. Of the 54 patients, 48 had peripheral vascular surgery as scheduled without coronary angiography, of whom 8 (17 per cent) had postoperative cardiac ischemic events. The occurrence of these eight cardiac events could not have been predicted preoperatively by any clinical factors but did correlate with the presence of thallium redistribution. Eight of 16 patients with thallium redistribution had cardiac events, whereas there were no such events in 32 patients whose thallium scan either was normal or showed only persistent defects (P less than 0.0001). Six other patients also had thallium redistribution but underwent coronary angiography before vascular surgery. All had severe multivessel coronary artery disease, and four underwent coronary bypass surgery followed by uncomplicated peripheral vascular surgery. These data suggest that patients without thallium redistribution are at a low risk for postoperative ischemic events and may proceed to have vascular surgery. Patients with redistribution have a high incidence of postoperative ischemic events and should be considered for preoperative coronary angiography and myocardial revascularization in an effort to avoid postoperative myocardial ischemia and to improve survival. Dipyridamole-thallium imaging is superior to clinical assessment and is safer and less expensive than coronary angiography for the determination of cardiac risk.

  6. Changes in coronary sinus pH during dipyridamole stress in patients with hypertrophic cardiomyopathy.

    PubMed Central

    Elliott, P. M.; Rosano, G. M.; Gill, J. S.; Poole-Wilson, P. A.; Kaski, J. C.; McKenna, W. J.

    1996-01-01

    OBJECTIVES: The presence of angina pectoris and myocardial scarring in patients with hypertrophic cardiomyopathy (HCM) suggests that myocardial ischemia is a factor in the pathophysiology of the disease. The clinical evaluation of ischaemia is problematic in HCM as baseline electrocardiographic abnormalities are frequent and thallium-201 perfusion abnormalities correlate poorly with anginal symptoms. Coronary sinus pH measurement using a catheter mounted pH electrode is a validated sensitive technique for the detection of myocardial ischaemia. METHODS AND RESULTS: 11 patients with HCM and chest pain (eight men; mean (SD) (range) age 36 (11) (19-53) years) and six controls (two men; mean (SD) (range) age 49 (11) (31-62) years) with atypical pain and normal coronary angiograms were studied. Eight patients with HCM had baseline ST segment depression of > or = 1 mm and four had reversible perfusion defects during stress 201TI scintigraphy. A catheter mounted hydrogen ion sensitive electrode was introduced into the coronary sinus and pH monitored continuously during dipyridamole infusion (0.56 mg/kg over four min). The maximal change in coronary sinus pH during dipyridamole stress was greater in patients with HCM than in controls (0.082 (0.083) (0 to -0.275) v 0.005 (0.006) (0 to -0.012), P = 0.02). In six patients (four men; mean (SD) (range) age 29 (9) (19-40 years) the development of chest pain was associated with a gradual decline in coronary sinus pH (mean 0.123 (0.089)), peaking at 442 (106) s. There were no relations among left ventricular dimensions, maximal wall thickness, and maximum pH change. In patients with HCM there was a correlation between maximum pH change and maximum heart rate during dipyridamole infusion (r = 0.70, P = 0.02). CONCLUSION: This study provides further evidence that chest pain in patients with HCM is caused by myocardial ischaemia. The role of myocardial ischaemia in the pathophysiology of the disease remains to be determined but

  7. Biokinetics of radiolabeled Iodophenylpentadecanoic acid (I-123-IPPA) and thallium-201 in a rabbit model of chronic myocardial infarction measured using a series of thermoluminescent dosimeters

    NASA Astrophysics Data System (ADS)

    Medich, David Christopher

    1997-09-01

    The biokinetics of Iodophenylpentadecanoic acid (123I-IPPA) during a chronic period of myocardial infarction were determined and compared to 201Tl. IPPA was assessed as a perfusion and metabolic tracer in the scintigraphic diagnosis of coronary artery disease. The myocardial clearance kinetics were measured by placing a series of thermoluminescent dosimeters (TLDs) on normal and infarcted tissue to measure the local myocardial activity content over time. The arterial blood pool activity was fit to a bi-exponential function for 201Tl and a tri-exponential function for 123I-IPPA to estimate the left ventricle contribution to TLD response. At equilibrium, the blood pool contribution was estimated experimentally to be less than 5% of the total TLD response. The method was unable to resolve the initial uptake of the imaging agent due in part to the 2 minute TLD response integration time and in part to the 30 second lag time for the first TLD placement. A noticeable disparity was observed between the tracer concentrations of IPPA in normal and ischemic tissue of approximately 2:1. The fitting parameters (representing the biokinetic eigenvalue rate constants) were related to the fundamental rate constants of a recycling biokinetic model. The myocardial IPPA content within normal tissue was elevated after approximately 130 minutes post injection. This phenomenon was observed in all but one (950215) of the IPPA TLD kinetics curves.

  8. Significance of dipyridamole-induced transient dilation of the left ventricle during thallium-201 scintigraphy in suspected coronary artery disease

    SciTech Connect

    Chouraqui, P.; Rodrigues, E.A.; Berman, D.S.; Maddahi, J. )

    1990-09-15

    The occurrence and significance of transient dilation of the left ventricle during dipyridamole stress-redistribution thallium-201 scintigraphy was studied in 73 patients who underwent both dipyridamole thallium-201 study and coronary angiography. Transient dilation ratio was calculated from planar anterior images by dividing the computer-derived left ventricular area on the initial image by that of the 4-hour image. In 11 patients with normal coronary arteriograms or less than 50% coronary stenosis, the transient dilation ratio was 0.98 +/- 0.046. An abnormal transient dilation ratio was defined as greater than or equal to 1.12, representing greater than or equal to 3 standard deviations above the mean normal value. When the 15 patients with an abnormal ratio were compared with the 58 with a normal ratio, the former group had a significantly higher frequency of 3 critical (greater than or equal to 90%) coronary stenoses (33 vs 5%), higher prevalence of collaterals (67 vs 24%), more extensive myocardial reversible defects by planar (71 vs 10%) or by single-photon emission computed tomography (87.5 vs 35%) imaging and a higher incidence of dipyridamole-induced anginal chest pain (53 vs 22%). No significant difference between the 2 groups was noted with respect to age, gender, prior myocardial infarction, single or double critical coronary stenosis, dipyridamole-induced ischemic electrocardiographic response and increased lung uptake. An abnormal transient dilation ratio of greater than or equal to 1.12 was a specific marker of multivessel (87%) or 3-vessel (85%) critical coronary artery disease.

  9. Intravenous dipyridamole thallium-201 SPECT imaging methodology, applications, and interpretations

    SciTech Connect

    Rockett, J.F.; Magill, H.L.; Loveless, V.S.; Murray, G.L. )

    1990-10-01

    Dipyridamole TI-201 imaging is an ideal alternative to exercise TI-201 scintigraphy in patients who are unwilling or unable to perform maximum exercise stress. The use of intravenous dipyridamole, alone or in combination with exercise, has not been approved for clinical practice by the Food and Drug Administration. Once approval is granted, the test will become a widely used and important component of the cardiac work-up. The indications, methodology, side effects, and utility of dipyridamole cardiac imaging in the clinical setting are discussed and a variety of examples presented.59 references.

  10. Quantitative relationship between global left ventricular thallium uptake and blood flow: effects of propranolol, ouabain, dipyridamole, and coronary artery occlusion

    SciTech Connect

    Melin, J.A.; Becker, L.C.

    1986-05-01

    The quantitative relationship between fractional myocardial thallium uptake and radioactive microsphere-determined flow was studied in 33 open chest dogs under baseline conditions during increased coronary flow (dipyridamole), decreased coronary flow (propranolol and coronary artery stenosis), inhibition of Na-K ATPase (ouabain), and regional infarction. Myocardial contents of thallium and microspheres were compared in left ventricular (LV) biopsies taken 5, 10, 15, 30, and 60 min after thallium injection, expressed as fractions of injected dose. Maximal LV thallium uptake occurred 10 min after injection and the 10-min values were therefore used for subsequent comparisons. Combining all dogs, fractional LV thallium content (% injected dose) correlated well with fractional LV blood flow (% cardiac output) (r = 0.95). However, for fractional LV flows in the low, normal, or moderately elevated range (LV flow/cardiac output less than 9%), thallium content consistently exceeded flow by about 15%. This relationship was not altered by ouabain or regional ischemia or infarction. For greatly elevated fractional LV flows (greater than 9%), thallium content was not significantly different from flow. To explain these differences, myocardial and systemic extraction fractions for thallium were determined in eight dogs with a dual tracer method. At baseline, myocardial extraction fraction was significantly greater than systemic (88 +/- 0.4% compared with 75 +/- 1%, p less than 0.001). During dipyridamole, myocardial extraction fraction decreased and myocardial and systemic values were no longer significantly different (82 +/- 1% compared with 79 +/- 1%). These results show that the fraction of injected thallium dose taken up by the LV myocardium exceeds the delivered fraction of cardiac output and is not altered by ouabain-induced inhibition or regional myocardial infarction.

  11. Reverse redistribution of thallium-201 detected by SPECT imaging after dipyridamole in angina pectoris

    SciTech Connect

    Popma, J.J.; Smitherman, T.C.; Walker, B.S.; Simon, T.R.; Dehmer, G.J. )

    1990-05-15

    Reverse redistribution refers to a thallium-201 perfusion defect that develops or becomes more evident on delayed imaging compared with the initial image immediately after stress. To determine the diagnostic importance of reverse redistribution after intravenous dipyridamole, thallium-201 single photon emission computed tomography and quantitative coronary arteriography were performed in 90 men with angina pectoris. Of the 250 myocardial segments analyzed, reverse redistribution was present in 17 (7%). Minimal coronary cross-sectional area in proximal vessel segments was less than or equal to 2.0 mm2 more often in regions with transient perfusion abnormalities than in regions with reverse redistribution (66 vs 29%, p less than 0.05). Compared with regions exhibiting transient perfusion abnormalities, regions with reverse redistribution had larger proximal arterial diameters (1.9 +/- 1.1 vs 1.3 +/- 1.1 mm, p less than 0.001) and cross-sectional areas (3.9 +/- 3.1 vs 2.2 +/- 2.6 mm2, p less than 0.001). Coronary artery dimensions and relative stenosis severity did not differ between those regions with normal perfusion and those with reverse redistribution. Reverse redistribution detected by thallium-201 single photon emission computed tomographic imaging after dipyridamole is uncommon, appears to occur as frequently in normal subjects as in patients undergoing coronary arteriography and does not indicate the presence of severe coronary artery disease.

  12. Comparison of ejection fraction and Goldman risk factor analysis to dipyridamole-thallium 201 studies in the evaluation of cardiac morbidity after aortic aneurysm surgery

    SciTech Connect

    McEnroe, C.S.; O'Donnell, T.F. Jr.; Yeager, A.; Konstam, M.; Mackey, W.C. )

    1990-04-01

    Associated coronary artery disease is the critical factor that influences early and late mortality after abdominal aortic aneurysm surgery. Dipyridamole-thallium 201 scintigraphy, left ventricular ejection fraction, and Goldman risk factor analysis have been suggested as preoperative noninvasive screening methods to detect significant coronary artery disease. In this series of 95 elective abdominal aortic aneurysm repairs dipyridamole-thallium 201 scintigraphy was highly predictive of the absence of perioperative cardiac morbidity (96% specificity, 44/46 normal scans, no cardiac morbidity), whereas ejection fraction (73% specificity, 31/42 normal ejection fraction, no cardiac morbidity) and Goldman risk factor analysis (84% specificity, 44/51 class I, no cardiac morbidity) were less. Furthermore, thallium redistribution on dipyridamole-thallium 201 scintigraphy leading to coronary angiography identified a significant number of patients with occult coronary artery disease who required preoperative coronary revascularization (8%, 8/95) and might have remained undetected on the basis of left ventricular ejection fraction or Goldman risk factor analysis. Finally, fixed thallium deficit, which some investigators have interpreted as a low probability finding for cardiac morbidity, was associated with a higher than expected incidence of cardiac complications. Forty-six percent (7/15) of all postoperative cardiac complications (three myocardial infarctions, three ischemic events, one death) occurred in patients with abdominal aortic aneurysms with fixed deficits. This suggests that patients with fixed deficits on dipyridamole-thallium 201 scintigraphy should be considered for later delayed (4 hours) thallium images or coronary angiography or both.

  13. Prevalence and correlates of increased lung/heart ratio of thallium-201 during dipyridamole stress imaging for suspected coronary artery disease

    SciTech Connect

    Villanueva, F.S.; Kaul, S.; Smith, W.H.; Watson, D.D.; Varma, S.K.; Beller, G.A. )

    1990-12-01

    There is little information concerning the prevalence and clinical correlates of increased pulmonary thallium-201 uptake during dipyridamole thallium-201 stress imaging. Accordingly, the clinical characteristics and quantitative thallium-201 findings were correlated with quantitative lung/heart thallium-201 ratio in 87 patients undergoing dipyridamole thallium-201 stress testing. Nineteen patients (22%) had an elevated ratio (greater than 0.51). These patients were more likely to have had an infarction, to be taking beta blockers, and have a lower rate-pressure product after dipyridamole administration than those with a normal ratio (p less than 0.03). An elevated ratio was associated with a greater likelihood of initial, redistribution and persistent defects, as well as left ventricular cavity dilatation on thallium-201 imaging (p less than 0.05). In addition, the number of myocardial segments demonstrating initial, redistribution and persistent defects was also greater in patients with increased ratios (p less than 0.03). Multivariate analysis demonstrated that the presence of redistribution and left ventricular cavity dilatation were the most significant correlates of lung/heart thallium-201 ratio. It is concluded that the prevalence of increased lung/heart thallium-201 ratio with dipyridamole thallium-201 stress imaging is similar to that seen with exercise stress imaging. As with exercise thallium-201 imaging, increased pulmonary thallium-201 uptake may be a marker of functionally more significant coronary artery disease.

  14. Dipyridamole-thallium tests are predictive of severe cardiac arrhythmias in patients with left ventricular hypertrophy

    SciTech Connect

    Saragoca, M.A.; Canziani, M.E.; Gil, M.A.; Castiglioni, M.L.; Cassiolato, J.L.; Barbieri, A.; Lima, V.C.; Draibe, S.A.; Martinez, E.E. )

    1991-01-01

    In a population of patients with chronic renal failure (CRF) and a high prevalence of left ventricular hypertrophy (LVH) undergoing chronic hemodialysis, the authors investigated the association between the results of dipyridamole-thallium tests (DTTs) and the occurrence of ventricular arrhythmias. They observed a positive significant association between positive DTTs and the occurrence of severe forms of ventricular arrhythmias. A significant association was also observed between the presence of severe LVH and the occurrence of severe ventricular arrhythmias. However, no association was found between the presence of LVH and the positivity of the DTT. As most of their patients with positive DTTs had unimpaired coronary circulations, they conclude that positive DTTs, although falsely indicative of impaired myocardial blood supply, does have an important clinical relevance, indicating increased risk of morbidity (and, possibly, mortality) due to ventricular arrhythmias in a population of CRF patients submitted to chronic renal function replacement program.

  15. Effects of propranolol and nifedipine on exercise-induced attack in patients variant angina: assessment by exercise thallium-201 myocardial scintigraphy with quantitative rotational tomography

    SciTech Connect

    Kugiyama, K.; Yasue, H.; Horio, Y.; Morikami, Y.; Fujii, H.; Koga, Y.; Kojima, A.; Takahashi, M.

    1986-08-01

    To examine the effects of propranolol and nifedipine on exercise-induced attack in patients with variant angina, exercise /sup 201/Tl myocardial scintigraphy with quantitative analysis by emission-computed tomography was performed in 20 patients with variant angina after oral propranolol (80 mg), nifedipine (20 mg), and placebo. Exercise-induced attack occurred in 11 patients on placebo, in 14 on propranolol, and in none on nifedipine. The exercise duration was significantly shorter in those on propranolol (p less than .05), but significantly longer in patients on nifedipine (p less than .05) than in those on placebo. The peak rate-pressure product was significantly lower in patients on propranolol (p less than .01), but did not change in those on nifedipine, as compared with that in patients on placebo. The size of the perfusion defect as measured by /sup 201/Tl tomography was significantly greater in patients on propranolol (p less than .05), but significantly less in those on nifedipine (p less than .01) than in those on placebo. In conclusion, propranolol does not suppress but rather may aggravate exercise-induced attack in patients with variant angina, while nifedipine suppresses it. This unfavorable effect of propranolol on exercise-induced attack in patients with variant angina is likely to be due to a reduction of regional myocardial blood flow.

  16. Physiological assessment of sensitivity of noninvasive testing for coronary artery disease

    SciTech Connect

    Simonetti, I.; Rezai, K.; Rossen, J.D.; Winniford, M.D.; Talman, C.L.; Hollenberg, M.; Kirchner, P.T.; Marcus, M.L. )

    1991-05-01

    The sensitivity of three noninvasive tests for coronary artery disease was assessed by means of quantitative indexes of disease severity in three different groups of patients. The overall population consisted of 110 subjects with limited coronary artery disease and no myocardial infarction. Planar dipyridamole-{sup 201}Tl scintigraphy was evaluated in 31 patients, computer-assisted exercise treadmill in 28, and high-dose dipyridamole echocardiography testing in 51. Sensitivity was assessed by rigorous gold standards to define disease severity, such as measurement of minimum cross-sectional area and percent area of stenosis, by quantitative computerized coronary angiography (Brown/Dodge method). On the basis of the results of previous studies, the presence of physiologically significant coronary artery disease was indicated by a stenotic minimum cross-sectional area (MCSA) of less than 2.0 mm{sup 2} or a greater than 75% area of stenosis. With MCSA as the gold standard, dipyridamole-{sup 201}Tl scintigraphy, computerized exercise treadmill, and dipyridamole echocardiography testing showed sensitivities of 52%, 54%, and 61%, respectively, in the three different patient cohorts enrolled. With percent area of stenosis as the gold standard, the sensitivity figures obtained for dipyridamole-{sup 201}Tl, computerized exercise treadmill, and dipyridamole echocardiography testing were 64%, 54%, and 69%, respectively. For each of the three tests, sensitivity increased with increasing lesion severity. Sensitivity was also better in patients with left anterior descending coronary (LAD) disease when compared with patients with left circumflex or right coronary artery disease. Results of these studies demonstrate that in patients with limited coronary artery disease none of the tests evaluated is definitely superior in sensitivity.

  17. A comparison of dipyridamole-thallium imaging and exercise testing in the prediction of postoperative cardiac complications in patients requiring arterial reconstruction

    SciTech Connect

    McPhail, N.V.; Ruddy, T.D.; Calvin, J.E.; Davies, R.A.; Barber, G.G.

    1989-07-01

    The individual and combined predictive values of dipyridamole-thallium imaging and exercise testing were compared in a prospective study of 70 patients who had abdominal aortic aneurysms or aortoiliac occlusive disease that required surgical repair. All patients were evaluated clinically by the same cardiologist and had exercise stress testing and dipyridamole-thallium imaging before admission for surgery. Ten patients were excluded from the study because they had evidence of severe ischemia when tested (ST segment depression greater than 2 mm on exercise testing, severe multivessel disease on thallium imaging). The remaining 60 patients were operated on (abdominal aortic aneurysm repair, 40; aortobifemoral repair, 17; femorofemoral graft, 3). The test results were withheld from the surgeon, anesthetist, and cardiologist before surgery. A total of 22 patients experienced major cardiac complications postoperatively (acute pulmonary edema, 17; acute myocardial infarction, 5; cardiac death, 2). Thallium imaging showed myocardial ischemia in 31/60 patients. Exercise testing was positive (greater than or equal to 1 mm ST segment depression) in 10/60 patients. Dipyridamole-thallium imaging with a high sensitivity and reasonable specificity is the initial test of choice. Exercise testing is a poor screening test because of its low sensitivity. The combination of the two tests gives the highest positive predictive value and the greatest likelihood ratio. Thus patients assessed initially and found to have positive thallium scan results may be further stratified by exercise testing.

  18. Sequential thallium-201 myocardial perfusion studies after successful percutaneous transluminal coronary artery angioplasty: delayed resolution of exercise-induced scintigraphic abnormalities

    SciTech Connect

    Manyari, D.E.; Knudtson, M.; Kloiber, R.; Roth, D.

    1988-01-01

    To characterize the sequential changes of myocardial perfusion scintigraphy in patients with coronary artery disease (CAD) after complete revascularization, 43 patients underwent exercise thallium-201 (/sup 201/Tl) myocardial perfusion scintigraphy before and at 9 +/- 5 days, 3.3 +/- 0.6, and 6.8 +/- 1.2 months after percutaneous transluminal coronary angioplasty (PTCA). Only patients with single-vessel CAD, without previous myocardial infarction, and without evidence of restenosis at 6 to 9 months after PTCA were included. Perfusion scans were analyzed blindly with the use of a new quantitative method to define regional myocardial perfusion in the topographic distribution of each coronary artery, which was shown to be reproducible (r = .94 or higher and SEE of 7% or less, between repeated measures by one and two operators). At 4 to 18 days after PTCA, the mean treadmill walking time increased by 123 +/- 42 sec, mean exercise-induced ST segment depression decreased by 0.6 +/- 0.3 mm, group maximal heart rate increased by 20 +/- 9 beats/min, and group systolic blood pressure at peak exercise increased by 24 +/- 10 mm Hg, compared with pre-PTCA values (p less than .001). However, no group differences were noted in these variables between the three post-PTCA stages. Myocardial perfusion in the distribution of the affected (dilated) coronary artery, on the other hand, improved progressively. In the 45 degree left anterior oblique view for instance, myocardial perfusion increased at 9 days after PTCA (from 68 +/- 24% before PTCA to 91 +/- 9%, p less than .001) and at 3.3 months after PTCA (101 +/- 8%, p less than .05 vs 9 days after PTCA), but no further significant changes were seen at 6.8 months after PTCA (102 +/- 8%). Similar changes were noted in the other two views. No relationship between minor complications during PTCA and delayed improvement on the /sup 201/Tl was observed.

  19. [Interest in myocardial scintigraphy following the arterial switch procedure for transposition of the great vessels].

    PubMed

    Acar, P; Maunoury, C; Bonnet, D; Sébahoun, S; Bonhoeffer, P; Hallaj, I; Aggoun, Y; Iserin, F; Sidi, D; Kachaner, J

    2001-05-01

    Coronary artery obstruction is the main late complication of the so-called arterial switch operation designed to repair transpositions of the great arteries in newborn infants by switching the great vessels and transferring the coronary ostia onto the posterior vessel. Our aim was to study the links between myocardial perfusion and coronary artery anatomy after the arterial switch operation. Forty-five patients (5.863 years) underwent a 201Tl myocardial SPECT and a selective coronary artery angiography. The latter was normal in 20 children: 13 had also a normal myocardial scan but 7 had myocardial perfusion defects including 2 with angina who had a very low coronary reserve at positron emission tomography. Twenty-five patients had severe coronary artery lesions: 5 with a normal myocardial scan and 20 with perfusion defects. Twelve out of these 20 underwent surgical revascularization and the SPECT images went back to normal in all within 6 months after surgery. Specificity and sensitivity of myocardial SPECT in detecting coronary artery lesions were 78% and 69% whereas positive and negative predictive values were 74 and 73%. We conclude that myocardial SPECT imaging is not the right way to detect late post arterial switch coronary artery lesions. It is helpful in decision making as to submit these children to surgical revascularization and in assessing its postoperative effectiveness.

  20. Influence of acquisition orbit on phase analysis of gated single photon emission computed tomography myocardial perfusion imaging for assessment of left ventricular mechanical dyssynchrony.

    PubMed

    Misaka, Tomofumi; Hosono, Makoto; Kudo, Takashi; Ito, Takamichi; Syomura, Tsutomu; Uemura, Masanobu; Okajima, Kaoru

    2017-04-01

    The association between left ventricular (LV) dyssynchrony parameters, given by phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), and acquisition orbits is unclear. The aim of this study was to assess the dependence of LV dyssynchrony parameters on acquisition orbits. Ninety-nine patients who underwent (201)Tl-gated SPECT MPI were categorized into minor hypoperfusion or major hypoperfusion groups. Forty-four patients who underwent (99m)Tc-tetrofosmin-gated SPECT MPI were categorized into minor hypoperfusion or major hypoperfusion groups. The major hypoperfusion group with (201)Tl was divided into inferior or non-inferior wall hypoperfusion subgroups, and anteroseptal or non-anteroseptal wall hypoperfusion subgroups. Gated SPECT MPI data over a 360° acquisition orbit (360° images) and a 180° acquisition orbit (180° images) were reconstructed, and histogram bandwidth (HBW) and phase standard deviation (PSD) were compared. Between 360° and 180° images with (201)Tl, there were significant differences in HBW and PSD both globally (HBW 34.8 ± 16.6 vs. 29.1 ± 10.2; PSD 8.8 ± 4.9 vs. 7.0 ± 2.3, p < 0.05 for both) and in the inferior wall (HBW 29.5 ± 15.5 vs. 23.3 ± 9.0; PSD 7.6 ± 4.6 vs. 5.6 ± 2.4, p < 0.001 for both) in the major hypoperfusion group, and also in the inferior wall in all subgroups of the major hypoperfusion group. In contrast, no segment had any significant differences in HBW or PSD between 360° and 180° images with (99m)Tc. Differences in acquisition orbit had a significant influence on HBW and PSD with (201)Tl-gated SPECT MPI in the inferior wall in patients with major hypoperfusion myocardium.

  1. IQ-SPECT for thallium-201 myocardial perfusion imaging: effect of normal databases on quantification.

    PubMed

    Konishi, Takahiro; Nakajima, Kenichi; Okuda, Koichi; Yoneyama, Hiroto; Matsuo, Shinro; Shibutani, Takayuki; Onoguchi, Masahisa; Kinuya, Seigo

    2017-07-01

    Although IQ-single-photon emission computed tomography (SPECT) provides rapid acquisition and attenuation-corrected images, the unique technology may create characteristic distribution different from the conventional imaging. This study aimed to compare the diagnostic performance of IQ-SPECT using Japanese normal databases (NDBs) with that of the conventional SPECT for thallium-201 ((201)Tl) myocardial perfusion imaging (MPI). A total of 36 patients underwent 1-day (201)Tl adenosine stress-rest MPI. Images were acquired with IQ-SPECT at approximately one-quarter of the standard time of conventional SPECT. Projection data acquired with the IQ-SPECT system were reconstructed via an ordered subset conjugate gradient minimizer method with or without scatter and attenuation correction (SCAC). Projection data obtained using the conventional SPECT were reconstructed via a filtered back projection method without SCAC. The summed stress score (SSS) was calculated using NDBs created by the Japanese Society of Nuclear Medicine working group, and scores were compared between IQ-SPECT and conventional SPECT using the acquisition condition-matched NDBs. The diagnostic performance of the methods for the detection of coronary artery disease was also compared. SSSs were 6.6 ± 8.2 for the conventional SPECT, 6.6 ± 9.4 for IQ-SPECT without SCAC, and 6.5 ± 9.7 for IQ-SPECT with SCAC (p = n.s. for each comparison). The SSS showed a strong positive correlation between conventional SPECT and IQ-SPECT (r = 0.921 and p < 0.0001), and the correlation between IQ-SPECT with and without SCAC was also good (r = 0.907 and p < 0.0001). Regarding diagnostic performance, the sensitivity, specificity, and accuracy were 80.8, 78.9, and 79.4%, respectively, for the conventional SPECT; 80.8, 80.3, and 82.0%, respectively, for IQ-SPECT without SCAC; and 88.5, 86.8, and 87.3%, respectively, for IQ-SPECT with SCAC, respectively. The area under the curve obtained via receiver operating

  2. Effect of Dipyridamole plus Aspirin on Hemodialysis Graft Patency

    PubMed Central

    Dixon, Bradley S.; Beck, Gerald J.; Vazquez, Miguel A.; Greenberg, Arthur; Delmez, James A.; Allon, Michael; Dember, Laura M.; Himmelfarb, Jonathan; Gassman, Jennifer J.; Greene, Tom; Radeva, Milena K.; Davidson, Ingemar J.; Ikizler, T. Alp; Braden, Gregory L.; Fenves, Andrew Z.; Kaufman, James S.; Cotton, James R.; Martin, Kevin J.; McNeil, James W.; Rahman, Asif; Lawson, Jeffery H.; Whiting, James F.; Hu, Bo; Meyers, Catherine M.; Kusek, John W.; Feldman, Harold I.

    2014-01-01

    BACKGROUND Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis. Procedural interventions may restore patency but are costly. Although there is no proven pharmacologic therapy, dipyridamole may be promising because of its known vascular antiproliferative activity. METHODS We conducted a randomized, double-blind, placebo-controlled trial of extended-release dipyridamole, at a dose of 200 mg, and aspirin, at a dose of 25 mg, given twice daily after the placement of a new arteriovenous graft until the primary outcome, loss of primary unassisted patency (i.e., patency without thrombosis or requirement for intervention), was reached. Secondary outcomes were cumulative graft failure and death. Primary and secondary outcomes were analyzed with the use of a Cox proportional-hazards regression with adjustment for prespecified covariates. RESULTS At 13 centers in the United States, 649 patients were randomly assigned to receive dipyridamole plus aspirin (321 patients) or placebo (328 patients) over a period of 4.5 years, with 6 additional months of follow-up. The incidence of primary unassisted patency at 1 year was 23% (95% confidence interval [CI], 18 to 28) in the placebo group and 28% (95% CI, 23 to 34) in the dipyridamole–aspirin group, an absolute difference of 5 percentage points. Treatment with dipyridamole plus aspirin significantly prolonged the duration of primary unassisted patency (hazard ratio, 0.82; 95% CI, 0.68 to 0.98; P = 0.03) and inhibited stenosis. The incidences of cumulative graft failure, death, the composite of graft failure or death, and serious adverse events (including bleeding) did not differ significantly between study groups. CONCLUSIONS Treatment with dipyridamole plus aspirin had a significant but modest effect in reducing the risk of stenosis and improving the duration of primary unassisted patency of newly created grafts. (ClinicalTrials.gov number, NCT00067119.) PMID

  3. Classical and pleiotropic actions of dipyridamole: Not enough light to illuminate the dark tunnel?

    PubMed

    Balakumar, Pitchai; Nyo, Ying Hui; Renushia, Raja; Raaginey, Devarajan; Oh, Ann Nah; Varatharajan, Rajavel; Dhanaraj, Sokkalingam A

    2014-09-01

    Dipyridamole is a platelet inhibitor indicated for the secondary prevention of transient ischemic attack. It inhibits the enzyme phosphodiesterase, elevates cAMP and cGMP levels and prevents platelet aggregation. Dipyridamole inhibits the cellular uptake of adenosine into red blood cells, platelets and endothelial cells that results in increased extracellular availability of adenosine, leading to modulation of cardiovascular function. The antiplatelet action of dipyridamole might offer therapeutic benefits in secondary stroke prevention in combination with aspirin. Inflammation and oxidative stress play an important role in atherosclerosis and thrombosis development, leading to stroke progression. Studies demonstrated anti-inflammatory, anti-oxidant and anti-proliferative actions of dipyridamole. These pleiotropic potentials of dipyridamole might contribute to improved therapeutic outcomes when used with aspirin in preventing secondary stroke. Dipyridamole was documented as a coronary vasodilator 5 decades ago. The therapeutic failure of dipyridamole as a coronary vasodilator is linked with induction of 'coronary steal' phenomenon in which by dilating resistance vessels in non-ischemic zone, dipyridamole diverts the already reduced blood flow away from the area of ischemic myocardium. Dipyridamole at high-dose could cause a marked 'coronary steal' effect. Dipyridamole, however, at low-dose could have a minimal hemodynamic effect. Low-dose dipyridamole treatment has a therapeutic potential in partially preventing diabetes mellitus-induced experimental vascular endothelial and renal abnormalities by enhancing endothelial nitric oxide signals and inducing renovascular reduction of oxidative stress. In spite of plenteous research on dipyridamole's use in clinics, its precise clinical application is still obscure. This review sheds lights on pleiotropic pharmacological actions and therapeutic potentials of dipyridamole.

  4. Myocardial scintigraphy with 201thallium in pediatric cardiology: A review of 52 cases

    SciTech Connect

    Bjoerkhem, G.E.; Evander, E.; White, T.; Lundstroem, N.R. )

    1990-01-01

    We report our experience of myocardial scintigraphy with 201thallium (201Tl) in 52 children, aged 4 days to 18 years, in which 80 studies were made primarily to demonstrate or exclude impaired myocardial perfusion. For analysis, the patients were divided into the following eight groups: group I, coronary artery malformations (five patients); group II, Kawasaki's syndrome (six patients); group III, arterial switch operation (seven patients); group IV, dilated cardiomyopathy (18 patients); group V, hypertrophic cardiomyopathy (four patients); group VI, myocardial dysfunction after surgery for congenital heart disease (five patients); group VII, pulmonary atresia (three patients); and group VIII, miscellaneous (four patients). Myocardial scintigraphy was performed with a planar or tomographic technique at rest or after exercise (four patients). Isotope-uptake defects, indicating impaired myocardial perfusion, were present in 14 patients, including small infants. Defects were seen in all groups except those with hypertrophic cardiomyopathy and pulmonary atresia. The absence of such defects in several of the patients with Kawasaki's syndrome was particularly valuable as it made coronary angiography unnecessary. In the other groups of patients myocardial scintigraphy was a valuable adjunct to other investigations.

  5. Dipyridamole thallium 201 scintigraphy to detect coronary artery disease before abdominal aortic surgery

    SciTech Connect

    Cutler, B.S.; Leppo, J.A.

    1987-01-01

    Dipyridamole thallium 201 scintigraphy (DTS) was used to screen 116 consecutive patients referred for aortic reconstructive surgery for coronary artery disease (CAD). Thallium redistribution was found to have the best statistical correlation with postoperative myocardial infarction (MI). No MIs occurred after aortic operations among 60 patients with normal scans compared with 8 of 31 patients with abnormal ones. The odds of a patient with abnormalities found by DTS having a postoperative MI were 12 times greater than for those with a normal scan. No symptom or combination of symptoms of CAD was as good as an abnormal DTS in identifying patients at risk. The incidence of MI was 7.0% for patients with symptomatic CAD and 8.5% for those who were asymptomatic. Cardiac complications gradually declined as surgeons gained confidence in the use of DTS, to the point where no postoperative MIs occurred during the final year of the study. DTS approaches the ideal preoperative test for CAD in patients with peripheral vascular disease. The test does not require exercise, is minimally invasive, safe, and of sufficient sensitivity to detect myocardial ischemia in the absence of symptoms. Furthermore, it is cost-effective; only those patients with an abnormal scan and an imperative need for aortic surgical treatment need further cardiac evaluation.

  6. Detection of residual jeopardized myocardium 3 weeks after myocardial infarction by exercise testing with thallium-201 mycardial scintigraphy

    SciTech Connect

    Turner, J.D.; Schwartz, K.M.; Logic, J.R.; Sheffield, L.T.; Kansal, S.; Roitman, D.I.; Mantle, J.A.; Russell, R.O.; Rackley, C.E.; Rogers, W.J.

    1980-04-01

    The usefulness of thallium-201 (Tl-201) exercise myocardial scintigraphy in identifying patients with multivessel coronary artery disease (MVCAD) and residual jeopardized myocardium after myocardial infarction (MI) was evaluated in 32 patients 3 weeks after MI. All patients underwent (1) limited multilead submaximal treadmill testing, (2) thallium-201 (Tl) myocardial scintigraphy at end-exercise and at rest, and (3) coronary and left ventricular angiography. Tl-201 perfusion defects were categorized as either reversible (ischemia) or irreversible (scar). The conventional exercise test was designated positive if there was ST depression > = 1mm and/or angina. Jeopardized myocardium (JEP) was defined angiographically as a segment of myocardium with normal or hypokinetic wall motion supplied by a significantly stenotic major coronary artery. MVCAD was defined as two or more significantly stenotic coronary arteries. Significant coronary stenosis was categorized as either 50 to 69% diameter narrowing or > = 70% diameter narrowing, thereby yielding, respectively, two subgroups each of jeopardized myocardium (JEP-50 and JEP-70) and MVCAD (MV-50 and MV-70). Clinical findings of angina, heart failure or ventricular arrhythmias during the late convalescent period after MI occurred in four of 10 patients (40%) with MV-50, five of 16 (31%) with MV-70, four of 10 (40%) with JEP-50 and five of 18 (28%) with JEP-70, and thus were insensitive for detecting MVCAD and JEP. Reversible ischemia and/or a positive conventional exercise test occurred in five of 10 patients (50%) with MV-50, 13 of 16 (81%) with MV-70, four of 10 (40%) with JEP-50 and 15 of 18 (83%) with JEP-70. All eight patients with both Tl-201 reversible ischemia and a positive conventional exercise test had JEP-70. In 30 of 31 patients (97%) with angiographic asynergy, Tl-201 scar was detected. No complications were associated with exercise testing.

  7. Tachycardic vs. pharmacologic stress myocardial perfusion imaging: differential implications in multi-vessel ischemia

    PubMed Central

    Nguyen, Thanh H; Horowitz, John D; Unger, Steven A

    2012-01-01

    Background In patients unable to exercise, potential methods of induction of reversible myocardial ischemia include physiological heart rate acceleration via pacing or dobutamine infusion and asymmetric coronary vasodilatation using dipyridamole. Although their bases for induction of ischemia are widely disparate, no direct comparison of these techniques has previously been reported. Methods We performed a randomised, paired comparison of dipyridamole and pacing myocardial perfusion imaging (MPI) in 28 patients in whom exercise stress imaging was precluded, comparing the detection, localisation and quantitation of ischemia. Results Reversible myocardial ischemia was detected in 21 patients, concordantly in 13 (p = 0.042). There was a high degree of concordance (p < 0.0001) regarding locations of sites of ischemia. While there was a good correlation (r = 0.74, p < 0.0001) between size of total ischemic zones with dipyridamole and pacing, the magnitude of ischemia tended to be greater with dipyridamole (mean percentage of left ventricular myocardium ± SD, 9.4 ± 11.0% vs. 7.0 ± 9.0%, p = 0.091). Furthermore, this difference resulted from accentuation of the primary ischemic zone with dipyridamole in patients with multi-vessel ischemia (mean ± SD, 28.1 ± 21.1% vs. 18.7 ± 16.1%, p = 0.046). Conclusions Despite major differences in mechanism(s) of induction of ischemia, dipyridamole and pacing produce similar results regarding detection, localisation and severity of ischemia. However, dipyridamole accentuates ischemia in primary (vs. secondary) ischemic zones, consistent with known induction of coronary “steal". This should be taken into account in interpretation of scan results. PMID:22254212

  8. Usefulness of the severity and extent of reversible perfusion defects during thallium-dipyridamole imaging for cardiac risk assessment before noncardiac surgery

    SciTech Connect

    Lette, J.; Waters, D.; Lapointe, J.; Gagnon, A.; Picard, M.; Cerino, M.; Kerouac, M. )

    1989-08-01

    Thallium-dipyridamole imaging is a very sensitive test for predicting cardiac events after noncardiac surgery, but it lacks specificity. To improve specificity, a semiquantitative scoring system was developed that combined dipyridamole-induced reversible left ventricular dilatation with scintigraphic indexes for severity and extent of reversible perfusion defects. Using this scoring system, patients were classified into low, intermediate and high risk subgroups. Thallium-dipyridamole imaging was performed in 66 patients before major general and vascular surgery. Thirty-nine patients classified as low risk (30 with normal scans and 9 with fixed defects) underwent surgery uneventfully. Surgery was cancelled in 6 patients with extensive thallium redistribution and coronary angiography was performed because of severe coronary artery disease in 5 and idiopathic dilated cardiomyopathy in 1. In the remaining 21 patients with thallium redistribution, a positive statistical correlation (p = 0.001) between scintigraphic indexes of severity and extent, and cardiac events was noted. Using cutoff values for the scintigraphic indexes, patients with reversible defects could be classified into intermediate and high risk subgroups. Only 1 of 11 patients at intermediate risk developed a complication, whereas 8 of 10 patients at high risk had a postoperative event (7 deaths and 1 myocardial infarction). Thus, using scintigraphic indexes for severity and extent, patients with reversible defects can be stratified into an intermediate risk subgroup that can safely undergo surgery and a high risk subgroup that requires coronary angiography.

  9. Multivariate clinical models and quantitative dipyridamole-thallium imaging to predict cardiac morbidity and death after vascular reconstruction

    SciTech Connect

    Lette, J.; Waters, D.; Lassonde, J.; Rene, P.; Picard, M.; Laurendeau, F.; Levy, R.; Cerino, M.; Nattel, S. )

    1991-08-01

    Patients with peripheral vascular disease have a high prevalence of coronary artery disease and are at increased risk for cardiac morbidity and death after vascular reconstruction. The present study was undertaken to assess the value of 18 clinical parameters, of 7 clinical scoring systems, and of quantitative dipyridamole-thallium imaging for predicting the occurrence of postoperative myocardial infarction or cardiac death. Vascular surgery was performed in 125 patients. Thirteen postoperative cardiac events occurred, including 10 cardiac deaths and 3 nonfatal infarctions. Clinical parameters were not useful in predicting postoperative outcome. All 63 patients with normal scan results or fixed perfusion defects underwent surgery uneventfully, whereas 21% (13/62) of patients with reversible defects had a postoperative cardiac complication. By use of quantitative scintigraphic indexes we found that patients with reversible defects could be stratified into intermediate and high-risk subgroups with postoperative event rates of 5% (2/47) and 85% (11/13), respectively, despite intensive postoperative monitoring and antianginal medication. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically, whereas dipyridamole-thallium imaging successfully identified all patients who had a postoperative cardiac event. By use of quantification we found that patients with reversible defects can be stratified into an intermediate risk subgroup that can undergo surgery with minimal complication rate and a high-risk subgroup that requires coronary angiography.

  10. Dipyridamole thallium imaging may not be a reliable screening test for coronary artery disease in patients undergoing vascular surgery

    SciTech Connect

    Marwick, T.H.; Underwood, D.A. )

    1990-01-01

    Dipyridamole thallium imaging has been proposed for cardiac risk stratification in patients undergoing peripheral vascular surgery. The purpose of this study was to define the benefit of this investigation in routine preoperative evaluation of these patients. The outcome of 86 patients undergoing vascular surgery procedures was examined in light of preoperative clinical assessment and dipyridamole SPECT thallium imaging (DST). Fifty-one patients (59%) were considered at high risk on clinical grounds, and 22 patients (26%) had perfusion defects. Ten patients suffered a perioperative coronary event, including unstable angina, myocardial infarction, or cardiac death. Seven of the patients with such events were among the 51 clinically high-risk subjects (14%). Three perioperative events occurred in the group of 19 patients with positive DST images who underwent surgery (16%), but the DST test failed to identify 7 patients who suffered coronary events. The frequency of abnormal thallium imaging was similar to the prevalence of angiographically significant coronary disease reported previously at this center, but considerably less than the rate of abnormal thallium imaging in past studies of vascular surgery patients. The application of the test to a low to moderate risk population is probably responsible for its lower predictive accuracy for coronary events. DST is not an ideal routine noninvasive technique for risk stratification in patients undergoing vascular surgery.

  11. Quantitative thallium-201 single photon emission computed tomography after oral dipyridamole for assessing the presence, anatomic location and severity of coronary artery disease

    SciTech Connect

    Borges-Neto, S.; Mahmarian, J.J.; Jain, A.; Roberts, R.; Verani, M.S.

    1988-05-01

    The objective of this investigation was to determine whether analysis of thallium-201 images as detected by quantitative single photon emission computed tomography after a single high oral dose of dipyridamole (300 mg) would accurately detect the presence of coronary artery disease and the anatomic location of the individual stenosis. Analyses were performed on 100 patients who concomitantly underwent diagnostic coronary arteriography and myocardial imaging. Tomographic myocardial perfusion defects were quantified using computer-generated polar maps. Eighty-four patients had significant coronary artery disease defined as greater than 50% luminal diameter stenosis. The sensitivity for detecting patients with coronary disease was 92% overall, 89% in patients without previous myocardial infarction and 97% in those with prior infarction. The technique had a sensitivity of 80, 87 and 51% for localizing coronary artery stenosis of the left anterior descending, the right coronary and the left circumflex artery, respectively. The corresponding specificity was 84, 92 and 92%. Furthermore, the presence of severe (greater than or equal to 70%) multivessel disease was identified with a sensitivity of 79% and a specificity of 87%. In conclusion, quantitative thallium-201 single photon emission computed tomography after oral dipyridamole has high sensitivity and specificity for diagnosing the presence of coronary disease, ascertaining the location of stenosed vessels and identifying the presence of multivessel disease.

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

    SciTech Connect

    Gibson, R.S.; Crampton, R.S.; Watson, D.D.; Taylor, G.J.; Carabello, B.A.; Holt, N.D.; Beller, G.A.

    1982-10-01

    The cause and associated pathophysiology of precordial ST-segment depression during acute inferior myocardial infarction (IMI) are controversial. To investigate this problem, electrocardiographic findings in 48 consecutive patients with acute IMI were prospectively compared with results of coronary angiography, submaximal exercise thallium-201 (/sup 201/Tl) scintigraphy and multigated blood pool imaging, all obtained 2 weeks after IMI, and with clinical follow-up at 3 months. Patients were classified according to the admission ECG obtained 3.3 +/- 3.1 hours after the onset of chest pain. Twenty-one patients (group A) had no or <1.0 mm ST-segment depression, and 27 (group B) had greater than or equal to1.0 mm ST-segment depression in two or more precordial (V/sub 1-6/) leads. Patients in group B had more prolonged chest pain after admission to the coronary care unit than those in group A (2.8 +/- 3.0 vs 1.2 +/- 1.1 hours, p<0.03), greater summed ST-segment elevation in leads II, III, aV/sub F/ (6.7 +/- 4.7 vs 3.3 +/- 4.5 mm, p<0.02), higher plasma peak creatine kinase levels (1133 +/- 781 vs 653 +/- 482 IU/l, p<0.01), a higher prevalence of ''true posterior'' infarction by ECG criteria (26% vs 5%, p<0.05), a lower radionuclide ejection fraction (46 +/- 9% vs 54 +/- 6%, p<0.001), more extensive infarct-related asynergy (p<0.001) and /sup 201/Tl perfusion abnormalities (p<0.01), more complications during hospitalization (p<0.03), and more cardiac events at 3 months (p<0.02). There were no significant differences between group A and group B in the extent of underlying coronary disease, prevalence of left anterior descending coronary artery disease, exercise-induced ST-segment depression or angina, /sup 201/Tl defects or wall motion abnormalities in anterior or septal segments.

  13. Effect of eating on thallium-201 myocardial redistribution after myocardial ischemia

    SciTech Connect

    Angello, D.A.; Wilson, R.A.; Palac, R.T.

    1987-09-01

    To determine whether eating a high-carbohydrate meal between initial and delayed postexercise thallium-201 (Tl-201) imaging affects detection of Tl-201 redistribution during exercise stress testing, 16 patients with stable angina performed 2 Tl-201 treadmill exercise stress tests within a 14-day interval. Immediately after initial postexercise imaging, patients either drank a commercially available instant breakfast preparation for the intervention test or drank an equivalent volume of water for the control test. Comparable exercise workloads were achieved by exercising patients to the same heart rate for both tests. The order of the 2 (intervention and control) tests were randomized. All patients had at least 1 region of Tl-201 myocardial redistribution on either their eating or control test scans, although only 7 of the 16 had positive treadmill exercise test responses. Forty-six regions showing Tl-201 myocardial redistribution were identified in all 144 regions examined. Significantly more of these regions were identified on control test scans than on eating test scans: 11 of 46 on both test scans, 6 of 46 only on eating test scans and 29 of 46 only on control scans (p less than 0.001). Consistent with results of the quantitative regional analysis, the percentage of Tl-201 clearance over 4 hours in the 46 Tl-201 myocardial redistribution regions was 39 +/- 8% for the eating tests and 29 +/- 8% for control tests (mean +/- standard deviation, p less than 0.003). In 4 patients diagnosis of transient ischemia would have been missed because their 14 Tl-201 myocardial redistribution regions were detected only on the control test scans.

  14. Thallium-201 myocardial SPECT in a patient with mirror-image dextrocardia and left bundle branch block.

    PubMed

    Turgut, Bülent; Kitapci, Mehmet T; Temiz, N Hakan; Unlü, Mustafa; Erselcan, Taner

    2003-09-01

    A 53-year-old male patient with a previous diagnosis of situs inversus with mirror-image dextrocardia underwent thallium-201 (Tl-201) stress-redistribution myocardial perfusion single photon emission computed tomography (SPECT). Electrocardiogram (ECG) obtained on right hemithorax revealed constant complete left bundle branch block. Tl-201 stress-redistribution SPECT images revealed abnormal perfusion with reversible ischemia in the anteroseptal, septal and inferoseptal walls. Coronary angiography performed 1 month after SPECT study was normal. This case illustrates that false positive reversible perfusion defects can be seen in patients with mirror-image dextrocardia associated with constant complete left bundle branch block. To our knowledge, this is the first reported case of mirror-image dextrocardia and constant complete left bundle branch block with false positive Tl-201 SPECT findings.

  15. Effects of hemoglobin level on myocardial washout rate of thallium-201 in patients with normal myocardial perfusion assessed by single-photon emission computed tomography.

    PubMed

    Kurisu, Satoshi; Sumimoto, Yoji; Ikenaga, Hiroki; Watanabe, Noriaki; Ishibashi, Ken; Dohi, Yoshihiro; Fukuda, Yukihiro; Kihara, Yasuki

    2017-04-05

    Myocardial perfusion single-photon emission computed tomography (SPECT) is often performed even in patients with suspected coronary artery disease complicated by anemia. We assessed the effects of hemoglobin level on myocardial washout rate of Thallium-201 (Tl-201) in patients with normal myocardial perfusion assessed by SPECT. The study population consisted of 231 patients with summed stress score of zero on SPECT. The mean myocardial washout rate of Tl-201 in the left ventricle was calculated from the stress and the redistribution Bull's eye map. Hematological test was performed within 2 weeks before gated SPECT. There were 135 male and 96 female patients with a mean age of 72.6 ± 9.0 years. The mean hemoglobin was 12.9 ± 1.9 mg/dl; the median was 13.2 mg/dl and the range was 8.0-16.5 mg/dl. There was a significant inverse correlation between hemoglobin level and myocardial washout rate of Tl-201 (r = -0.45, p < 0.001). Univariate linear regression analysis showed that age, female, body mass index, serum creatinine, hemoglobin, end-diastolic volume, and ejection fraction were associated with myocardial washout rate of Tl-201. Multivariate analysis showed that only hemoglobin was the independent predictor of myocardial washout rate of Tl-201 (β = -0.35, p < 0.001). Our data suggested that anemia was a major determinant of increased myocardial washout rate of Tl-201 in patients with normal myocardial perfusion on SPECT.

  16. Association between aortic valve calcification and myocardial ischemia, especially in asymptomatic patients.

    PubMed

    Yamazato, Ryo; Yamamoto, Hideya; Tadehara, Futoshi; Teragawa, Hiroki; Kurisu, Satoshi; Dohi, Yoshihiro; Ishibashi, Ken; Kunita, Eiji; Utsunomiya, Hiroto; Oka, Toshiharu; Kihara, Yasuki

    2012-08-01

    Aortic valve calcification (AVC) is recognized as a manifestation of systemic arteriosclerosis. However, it is unclear whether AVC is associated with myocardial ischemia. Stress myocardial perfusion SPECT (MPS) is widely used for the diagnosis of myocardial ischemia. However, routine MPS is not recommended, particularly in asymptomatic patients. Accordingly, we investigated the hypothesis that the presence of AVC is strongly associated with inducible myocardial ischemia, even among asymptomatic patients. We investigated 669 consecutive patients who underwent both adenosine stress (201)Tl MPS and echocardiography. We evaluated the extent and severity of myocardial ischemia by the summed difference score (SDS). We defined the presence of myocardial ischemia as SDS ≥ 3 and moderate to severe ischemia as SDS ≥ 8. We classified the severity of AVC according to the number of affected aortic leaflets. We also compared the mean SDS and the prevalence of SDS ≥ 3 and SDS ≥ 8 among patients stratified by the severity of AVC. The presence of AVC was significantly associated with myocardial ischemia (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.10-2.23; P = 0.013) and moderate to severe ischemia (OR, 2.16; 95% CI, 1.26-3.80; P = 0.0061). In 311 asymptomatic patients, AVC was strongly associated with moderate to severe ischemia (OR, 4.31; 95% CI, 1.67-12.8; P = 0.0043). However, the SDS value and the prevalence of SDS ≥ 3 and SDS ≥ 8 did not increase with increasing number of affected aortic leaflets. The presence of AVC may be associated with the presence of myocardial ischemia, particularly in asymptomatic patients. However, we found no association between the extent of AVC and inducible myocardial ischemia. The presence of AVC may be a useful anatomic marker to help identify patients at high risk of myocardial ischemia, particularly asymptomatic patients.

  17. Verapamil prevents silent myocardial perfusion abnormalities during exercise in asymptomatic patients with hypertrophic cardiomyopathy

    SciTech Connect

    Udelson, J.E.; Bonow, R.O.; O'Gara, P.T.; Maron, B.J.; Van Lingen, A.; Bacharach, S.L.; Epstein, S.E.

    1989-05-01

    Recent studies indicate that reversible 201Tl perfusion defects, compatible with silent myocardial ischemia, commonly develop during exercise in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy (HCM). To determine whether this represents a dynamic process that may be modified favorably by medical therapy, we studied 29 asymptomatic or minimally symptomatic patients with HCM, aged 12-55 years (mean, 28), with exercise 201Tl emission computed tomography under control conditions and again after 1 week of oral verapamil (mean dosage, 453 mg/day). Treadmill time increased slightly during verapamil (21.0 +/- 3.6 to 21.9 +/- 2.7 minutes, p less than 0.005), but peak heart rate-blood pressure product was unchanged (26.3 +/- 6.0 X 10(3)) compared with 25.0 +/- 6.4 X 10(3). Two midventricular short-axis images per study were divided into five regions each, and each of these 10 regions was then analyzed on a 0-2 scale by three observers blinded with regard to the patients' therapy. Average regional scores of 1.5 or less were considered to represent perfusion defects, and a change in regional score of 0.5 or more was considered to constitute a significant change. During control studies, 15 patients (52%) developed perfusion defects with exercise (average, 3.7 regions per patient). In 14 of these patients, all perfusion defects completely reversed after 3 hours of rest; one patient had fixed defects. After administration of verapamil, exercise perfusion scores improved in 10 of the 14 patients (71%) with reversible defects; there was overall improvement in 34 of 50 (68%) regions with initially reversible perfusion defects.

  18. Effects of coronary angioplasty and reperfusion on distribution of myocardial flow

    SciTech Connect

    Wahr, D.W.; Ports, T.A.; Botvinick, E.H.; Dae, M.; Schechtmann, N.; Huberty, J.; Hattner, R.S.; O'Connell, J.W.; Turley, K.

    1985-08-01

    To assess the effects of angioplasty (PTCA) and intracoronary streptokinase (ICSK) on relative myocardial perfusion, the authors administered /sup 99m/Tc-macroaggregated albumin (MAA) to the uninvolved coronary artery before successful PTCA in 33 patients and before successful infusion of ICSK in eight patients and of /sup 111/In-MAA into the same vessel after the intervention. In 10 patients who underwent PTCA, MAA was injected into the involved, instrumented coronary artery. Computer-processed images were acquired in registry and compared. Similar scintigraphic studies were performed in six control patients and in 11 in whom planned interventions were not performed or were unsuccessful. Distribution of MAA was also compared with angiographic results and with the distribution of /sup 201/Tl on images obtained in patients at rest or on redistribution images obtained before and soon after intervention in 22 patients. In control patients and those studied after aborted or unsuccessful intervention, scintigraphic results showed excellent correlation with the angiographic anatomy and were without serial change. When MAA was injected into the uninvolved vessel, the scintigram revealed evidence of collateral perfusion with retraction of the perfusion zone from that of the involved coronary in 19 of 33 patients undergoing PTCA and in three of eight of those receiving ICSK. When MAA was injected into the involved artery, a relative increase in perfusion was seen in eight of 10 patients after PTCA. Although 30 patients demonstrated scintigraphic evidence of collateral vessels, only 10 patients had angiographic evidence of collateral circulation before intervention. The distribution of /sup 201/Tl demonstrated little change in its global pattern and regions previously supplied by collaterals were generally well perfused after intervention.

  19. Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke.

    PubMed

    Sacco, Ralph L; Diener, Hans-Christoph; Yusuf, Salim; Cotton, Daniel; Ounpuu, Stephanie; Lawton, William A; Palesch, Yuko; Martin, Reneé H; Albers, Gregory W; Bath, Philip; Bornstein, Natan; Chan, Bernard P L; Chen, Sien-Tsong; Cunha, Luis; Dahlöf, Björn; De Keyser, Jacques; Donnan, Geoffrey A; Estol, Conrado; Gorelick, Philip; Gu, Vivian; Hermansson, Karin; Hilbrich, Lutz; Kaste, Markku; Lu, Chuanzhen; Machnig, Thomas; Pais, Prem; Roberts, Robin; Skvortsova, Veronika; Teal, Philip; Toni, Danilo; Vandermaelen, Cam; Voigt, Thor; Weber, Michael; Yoon, Byung-Woo

    2008-09-18

    Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens--aspirin plus extended-release dipyridamole (ASA-ERDP) versus clopidogrel. In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke. The secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075), followed by superiority testing, was planned. A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke occurred in 916 patients (9.0%) receiving ASA-ERDP and in 898 patients (8.8%) receiving clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for ASA-ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events among ASA-ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365 [3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage (hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major hemorrhagic event was similar in the two groups (1194 ASA-ERDP recipients [11.7%], vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11). The trial did not meet the predefined criteria for noninferiority but showed similar rates of recurrent stroke with ASA-ERDP and with clopidogrel. There is no evidence that either of the two treatments was superior to the other in the prevention of recurrent stroke. (ClinicalTrials.gov number, NCT00153062.) 2008 Massachusetts Medical Society

  20. Aspirin and Extended-Release Dipyridamole versus Clopidogrel for Recurrent Stroke

    PubMed Central

    Sacco, Ralph L.; Diener, Hans-Christoph; Yusuf, Salim; Cotton, Daniel; Ôunpuu, Stephanie; Lawton, William A.; Palesch, Yuko; Martin, Reneé H.; Albers, Gregory W.; Bath, Philip; Bornstein, Natan; Chan, Bernard P.L.; Chen, Sien-Tsong; Cunha, Luis; Dahlöf, Björn; De Keyser, Jacques; Donnan, Geoffrey A.; Estol, Conrado; Gorelick, Philip; Gu, Vivian; Hermansson, Karin; Hilbrich, Lutz; Kaste, Markku; Lu, Chuanzhen; Machnig, Thomas; Pais, Prem; Roberts, Robin; Skvortsova, Veronika; Teal, Philip; Toni, Danilo; VanderMaelen, Cam; Voigt, Thor; Weber, Michael; Yoon, Byung-Woo

    2009-01-01

    BACKGROUND Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens — aspirin plus extendedrelease dipyridamole (ASA–ERDP) versus clopidogrel. METHODS In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke. The secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075), followed by superiority testing, was planned. RESULTS A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke occurred in 916 patients (9.0%) receiving ASA–ERDP and in 898 patients (8.8%) receiving clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for ASA–ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events among ASA–ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365 [3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage (hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major hemorrhagic event was similar in the two groups (1194 ASA–ERDP recipients [11.7%], vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11). CONCLUSIONS The trial did not meet the predefined criteria for noninferiority but showed similar rates of recurrent stroke with ASA–ERDP and with clopidogrel. There is no evidence that either of the two treatments was superior to the other in the prevention of recurrent stroke. PMID:18753638

  1. Dipyridamole prevents the coconut oil-induced hypercholesterolemia. A study on lipid plasma and lipoprotein composition.

    PubMed

    García-Fuentes, Eduardo; Gil-Villarino, Almudena; Zafra, Ma Flor; García-Peregrín, Eduardo

    2002-03-01

    For a better understanding of the hypolipidemic function of dipyridamole, we have studied the comparative effects of diet supplementation with 10% coconut oil with and without dipyridamole on the lipid plasma and lipoprotein composition in chicks. This study was performed under postprandial and food-deprivation (12h) conditions. Coconut oil induced a clear hypercholesterolemia under both feeding conditions. Simultaneous administration of dipyridamole maintained total and esterified cholesterol at levels similar to those observed in control animals sacrificed under postprandial conditions. Under these conditions, our results also show that dipyridamole significantly reduced cholesterol levels in all the chick plasma lipoproteins that were increased by coconut oil administration. Nevertheless, it should be emphasised that the levels of total cholesterol found in intermediate- and very-low-density lipoproteins were lower than in control. All chemical components of these fractions were significantly decreased by dipyridamole. The effects were not significant in chicks deprived of food. In conclusion, our results show that the hypercholesterolemia induced by coconut oil was prevented by dipyridamole. To our knowledge, this is one of the first reports on the antihypercholesterolemic effects of dipyridamole.

  2. Diagnostic accuracy of thallium-201 myocardial perfusion imaging

    SciTech Connect

    Beller, G.A. )

    1991-09-01

    Myocardial thallium-201 (Tl-201) imaging performed in conjunction with exercise stress has enhanced the accuracy of detecting coronary artery disease among patients with chest pain. Sensitivity and specificity of qualitative visual Tl-201 scintigraphy for detection of coronary artery disease average 84% and 87%, respectively. Quantitative analysis of planar Tl-201 scintigrams has yielded sensitivity and specificity in the 90% range. Single photon emission computed tomographic imaging is associated with even higher sensitivity but with specificity in the 82-85% range. Perfusion defects representing ischemia can now be distinguished from scar by demonstration of delayed Tl-201 redistribution or enhanced uptake after reinjection of a second dose of Tl-201. Stenoses of the left circumflex coronary artery are less easily detected than lesions of the right and left anterior descending coronary arteries. False-positive Tl-201 perfusion defects may occur as a result of attenuation artifacts, most often caused by overlying breast tissue or by a high left hemidiaphragm. Patient motion during acquisition of single photon emission computed tomographic images results in artifactual defects on reconstruction. Abnormal Tl-201 uptake has been noted in patients with (1) left bundle branch block and normal coronary arteries, (2) hypertrophic cardiomyopathy, and (3) progressive systemic sclerosis.

  3. Regional cardiac wall motion from gated myocardial perfusion SPECT studies

    NASA Astrophysics Data System (ADS)

    Smith, M. F.; Brigger, P.; Ferrand, S. K.; Dilsizian, V.; Bacharach, S. L.

    1999-06-01

    A method for estimating regional epicardial and endocardial wall motion from gated myocardial perfusion SPECT studies has been developed. The method uses epicardial and endocardial boundaries determined from four long-axis slices at each gate of the cardiac cycle. The epicardial and endocardial wall position at each time gate is computed with respect to stationary reference ellipsoids, and wall motion is measured along lines normal to these ellipsoids. An initial quantitative evaluation of the method was made using the beating heart from the dynamic mathematical cardiac torso (MCAT) phantom, with and without a 1.5-cm FWHM Gaussian blurring filter. Epicardial wall motion was generally well-estimated within a fraction of a 3.56-mm voxel, although apical motion was overestimated with the Gaussian filter. Endocardial wall motion was underestimated by about two voxels with and without the Gaussian filter. The MCAT heart phantom was modified to model hypokinetic and dyskinetic wall motion. The wall motion analysis method enabled this abnormal motion to be differentiated from normal motion. Regional cardiac wall motion also was analyzed for /sup 201/Tl patient studies. Estimated wall motion was consistent with a nuclear medicine physician's visual assessment of motion from gated long-axis slices for male and female study examples. Additional research is required for a comprehensive evaluation of the applicability of the method to patient studies with normal and abnormal wall motion.

  4. Combined dipyridamole and aspirin pellet formulation for improved oral drug delivery. Part 1: Development pharmaceutics.

    PubMed

    Deasy, P B; Murtagh, P W

    1996-01-01

    The dissolution profile of various weight fractions of dipyridamole: hydropropylmethylcellulose acetate succinate (HPMC-AS) and dipyridamole: hydroxypropylmethylcellulose phthalate co-precipitates lead to the choice of 1:2 dipyridamole: HPMC-AS as the controlled-release component. It was deposited to form two-third of the total dose as an inner layer on inert sucrose cores by air suspension coating for release mainly in the small intestine. Further examination of this material by IR spectroscopy, differential scanning calorimetry and X-ray diffraction indicated some free drug, preferentially soluble under gastric pH conditions. One-third of the total dose was applied by pan coating as an outer layer of micronized dipyridamole around the inner enteric co-precipitate layer. Aspirin-loaded cores were prepared also by pan coating for use in the final product, which contained both anti-platelet drugs.

  5. Ocular Applications of Dipyridamole: A Review of Indications and Routes of Administration

    PubMed Central

    Isakov, Itzhak; Wlassoff, Wjatschesslaw; Ingram, April; Barishak, Y. Robert

    2016-01-01

    Abstract Dipyridamole was introduced decades ago as a treatment for angina, subsequently found to inhibit platelet aggregation. It is most commonly used, and approved for use in thromboembolism prevention, following surgery. Some of its recognized effects such as adenosine uptake inhibition, elevation of cAMP and cGMP levels, vasodilation, and tissue perfusion are important in various ocular disorders. For this reason, dipyridamole represents an interesting candidate as a therapeutic target for the treatment of eye disorders affecting different ocular structures. The aim of this article is to review the evidence and current understanding of the mechanisms by which dipyridamole exerts its effects on different ocular tissues, discuss the role of dipyridamole in clinical practice, and highlight areas of use and routes of administration. PMID:26696547

  6. Correlation between myocardial dysfunction and perfusion impairment in diabetic rats with velocity vector imaging and myocardial contrast echocardiography.

    PubMed

    Wei, Zhangrui; Zhang, Haibin; Su, Haili; Zhu, Ting; Zhu, Yongsheng; Zhang, Jun

    2012-11-01

    The purpose of this study was to investigate whether myocardial systolic dysfunction and perfusion impairment occur in diabetic rats, and to assess their relationship using velocity vector imaging (VVI) and myocardial contrast echocardiography (MCE). Forty-six rats were randomly divided into either control or the diabetes mellitus (DM) groups. DM was induced by intraperitoneal administration of streptozotocin. Twelve weeks later, 39 survival rats underwent VVI and MCE in short-axis view at the middle level of the left ventricle, both at rest and after dipyridamole stress. VVI-derived contractile parameters included peak systolic velocity (Vs ), circumferential strain (εc ), strain rate (SRc ), and their reserves. MCE-derived perfusion parameters consisted of myocardial blood flow (MBF) and myocardial flow reserve (MFR). At rest, SRc in the DM group was significantly lower than in the control group, Vs , εc , and MBF did not differ significantly between groups. After dipyridamole stress, all VVI parameters and their reserves in the DM group were significantly lower than those in the control group, MBF and MFR were substantially lower than those in the control group, too. Meanwhile, significant correlations between VVI parameter reserves and MFR were observed in the DM group. Both myocardial systolic function and perfusion were impaired in DM rats. Decreased MFR could be an important contributor to the reduction in myocardial contractile reserve.

  7. Protection of low density lipoprotein oxidation at chemical and cellular level by the antioxidant drug dipyridamole.

    PubMed Central

    Iuliano, L.; Colavita, A. R.; Camastra, C.; Bello, V.; Quintarelli, C.; Alessandroni, M.; Piovella, F.; Violi, F.

    1996-01-01

    1. The oxidative modification of low density lipoprotein (LDL) is thought to be an important factor in the initiation and development of atherosclerosis. Natural and synthetic antioxidants have been shown to protect LDL from oxidation and to inhibit atherosclerosis development in animals. Synthetic antioxidants are currently being tested, by they are not necessarily safe for human use. 2. We have previously reported that dipyridamole, currently used in clinical practice, is a potent scavenger of free radicals. Thus, we tested whether dipyridamole could affect LDL oxidation at chemical and cellular level. 3. Chemically induced LDL oxidation was made by Cu(II), Cu(II) plus hydrogen peroxide or peroxyl radicals generated by thermolysis of 2,2'-azo-bis(2-amidino propane). Dipyridamole, (1-10 microM), inhibited LDL oxidation as monitored by diene formation, evolution of hydroperoxides and thiobarbituric acid reactive substances, apoprotein modification and by the fluorescence of cis-parinaric acid. 4. The physiological relevance of the antioxidant activity was validated by experiments at the cellular level where dipyridamole inhibited endothelial cell-mediated LDL oxidation, their degradation by monocytes, and cytotoxicity. 5. In comparison with ascorbic acid, alpha-tocopherol and probucol, dipyridamole was the more efficient antioxidant with the following order of activity: dipyridamole > probucol > ascorbic acid > alpha-tocopherol. The present study shows that dipyridamole inhibits oxidation of LDL at pharmacologically relevant concentrations. The inhibition of LDL oxidation is unequivocally confirmed by use of three different methods of chemical oxidation, by several methods of oxidation monitoring, and the pharmacological relevance is demonstrated by the superiority of dipyridamole over the naturally occurring antioxidants, ascorbic acid and alpha-tocopherol and the synthetic antioxidant probucol. Images Figure 6 PMID:8968553

  8. Chest pain with myocardial ischemia in a child: should we think about coronary slow flow phenomenon?

    PubMed

    Kocabaş, Abdullah; Kardelen, Fırat; Akçurin, Gayaz; Ertuğ, Halil

    2013-10-01

    The coronary slow flow phenomenon (CSFP) is an angiographic finding characterized by delayed opacification of epicardial coronary arteries in the absence of stenotic lesion. Herein, we present a 13-year-old boy with recurrent chest pain who was diagnosed with acute ST-segment elevation myocardial infarction associated with CSFP, which has not been reported previously in the pediatric age group. Coronary angiography revealed only the presence of slow flow in the left anterior descending (LAD) coronary artery. Myocardial perfusion scintigraphy revealed a reversible perfusion defect in the LAD territory, which regressed partially at rest and showed complete improvement after dipyridamole infusion. All the symptoms, electrocardiogram abnormalities and cardiac markers returned to normal after dipyridamole treatment during the follow-up. We conclude that CSFP should be kept in mind in the differential diagnosis of chest pain with myocardial ischemia in the pediatric age group.

  9. Semi-automated measurements of heart-to-mediastinum ratio on 123I-MIBG myocardial scintigrams by using image fusion method with chest X-ray images

    NASA Astrophysics Data System (ADS)

    Kawai, Ryosuke; Hara, Takeshi; Katafuchi, Tetsuro; Ishihara, Tadahiko; Zhou, Xiangrong; Muramatsu, Chisako; Abe, Yoshiteru; Fujita, Hiroshi

    2015-03-01

    MIBG (iodine-123-meta-iodobenzylguanidine) is a radioactive medicine that is used to help diagnose not only myocardial diseases but also Parkinson's diseases (PD) and dementia with Lewy Bodies (DLB). The difficulty of the segmentation around the myocardium often reduces the consistency of measurement results. One of the most common measurement methods is the ratio of the uptake values of the heart to mediastinum (H/M). This ratio will be a stable independent of the operators when the uptake value in the myocardium region is clearly higher than that in background, however, it will be unreliable indices when the myocardium region is unclear because of the low uptake values. This study aims to develop a new measurement method by using the image fusion of three modalities of MIBG scintigrams, 201-Tl scintigrams, and chest radiograms, to increase the reliability of the H/M measurement results. Our automated method consists of the following steps: (1) construct left ventricular (LV) map from 201-Tl myocardium image database, (2) determine heart region in chest radiograms, (3) determine mediastinum region in chest radiograms, (4) perform image fusion of chest radiograms and MIBG scintigrams, and 5) perform H/M measurements on MIBG scintigrams by using the locations of heart and mediastinum determined on the chest radiograms. We collected 165 cases with 201-Tl scintigrams and chest radiograms to construct the LV map. Another 65 cases with MIBG scintigrams and chest radiograms were also collected for the measurements. Four radiological technologists (RTs) manually measured the H/M in the MIBG images. We compared the four RTs' results with our computer outputs by using Pearson's correlation, the Bland-Altman method, and the equivalency test method. As a result, the correlations of the H/M between four the RTs and the computer were 0.85 to 0.88. We confirmed systematic errors between the four RTs and the computer as well as among the four RTs. The variation range of the H

  10. Comparison of dipyridamole-handgrip test and bicycle exercise test for thallium tomographic imaging

    SciTech Connect

    Huikuri, H.V.; Korhonen, U.R.; Airaksinen, J.; Ikaeheimo, M.J.H.; Heikkilae, J.T.; Takkunen, J.T.

    1988-02-01

    Seventy-three patients with angina pectoris and 20 with atypical chest pain, who underwent coronary angiography, were examined by single-photon emission computed thallium tomography (TI-SPECT) using a combined dipyridamole-handgrip stress test. Perfusion defects were detected in 78 of 81 patients with angiographically significant coronary artery disease (CAD) (sensitivity 96%). In 9 of 12 patients without CAD, the thallium images were normal (specificity 75%). Thirty-five patients with CAD were reexamined by TI-SPECT using a dynamic bicycle exercise stress test. The sensitivity of the dipyridamole-handgrip test did not differ from the bicycle exercise test in diagnosing the CAD (97% vs 94%). Multiple thallium defects were seen in 19 of 22 (86%) patients with multivessel CAD by the dipyridamole-handgrip test but only in 14 of 22 (64%) by the bicycle exercise test. Noncardiac side-effects occurred in 17 of 93 (18%) patients after dipyridamole infusion. Cardiac symptoms were less common during the dipyridamole-handgrip test than during the bicycle exercise (15% vs 76%, p less than 0.01). These data suggest that the dipyridamole-handgrip test is a useful alternative stress method for thallium perfusion imaging, particularly in detecting multivessel CAD.

  11. Functional significance of coronary collateral circulation during dynamic exercise evaluated by thallium-201 myocardial scintigraphy.

    PubMed Central

    Wainwright, R J; Maisey, M N; Edwards, A C; Sowton, E

    1980-01-01

    Sixty-five patients with angiographically documented coronary artery disease were investigated by thallium-201 (201Tl) scintigraphy to determine the role of the collateral circulation during dynamic exercise. Fifty-three patients had complete proximal occlusion of at least one major coronary artery. One patient had total occlusion of all three major coronary arteries. Sixty-four collateral channels were identified, graded, and compared with corresponding regions of the myocardial scintigram. Tracer uptake was also graded and classified as various degrees of protection from ischaemia. A significant correlation between good collaterals with complete protection and poor or absent collaterals with no protection was noted. Seventeen patients (20 occluded vessels) had total coronary occlusion without myocardial infarction. Collaterals conferred protection in 9/15 occlusions whereas no protection was seen in five occlusions without collaterals. There was no difference in the protective role of homocoronary and heterocoronary collateral vessels. Hypertrophy of the first septal left anterior descending perforator conferred significant protection from ischaemia in contrast to bridging collaterals and ghosting. During exercise the right coronary bed is preferentially protected from ischaemia, in contrast to the left anterior descending territory. This probably reflects the direction of a transmural flow gradient between left and right ventricles during exercise. Images PMID:7356862

  12. Dipyridamole monotherapy in schizophrenia: pilot of a novel treatment approach by modulation of purinergic signaling.

    PubMed

    Wonodi, Ikwunga; Gopinath, Hirekatur V; Liu, Judy; Adami, Helene; Hong, L Elliot; Allen-Emerson, Robert; McMahon, Robert P; Thaker, Gunvant K

    2011-11-01

    Emerging data indicate the neuromodulator adenosine may play a role in the therapeutics of schizophrenia. Adenosine A(2A) receptor stimulation exerts a functional antagonism at postsynaptic D(2) receptors. Data from animal models relevant to schizophrenia support a therapeutic effect of modulating adenosinergic transmission in the ventral striatum. One previous clinical trial showed superiority of adjunctive dipyridamole, an adenosine reuptake inhibitor, compared to placebo in ameliorating positive symptoms in schizophrenia patients. The aim of this study was to examine the effects of dipyridamole monotherapy of 200 mg/day on positive and negative symptoms, with the goal of determining dosing for future adjunctive studies in schizophrenia. Twenty symptomatic schizophrenia participants were randomized to a 6-week double-blind trial comparing olanzapine (20 mg/day) to dipyridamole monotherapy (200 mg/day). Thirteen participants completed the treatment phase (eight on dipyridamole; five on olanzapine). The olanzapine group showed a trend (p = 0.08) for superiority on BPRS total scores (mean ± SD: total BPRS score decreasing from 36.8 ± 2.3 at week 1, to 33.2 ± 5.5 at the end of the study). The mean total BPRS scores decreased from 36.4 ± 5.3 to 34.0 ± 7.7 in the dipyridamole group. Although these pilot data do not support a significant antipsychotic effect of dipyridamole monotherapy, the results provide some evidence for examining dipyridamole (200 mg/day) as adjunct to symptomatic antipsychotic-treated schizophrenia patients.

  13. Experimental studies of the physiologic properties of technetium-99m agents: Myocardial transport of perfusion imaging agents

    SciTech Connect

    Meerdink, D.J.; Leppo, J.A. )

    1990-10-16

    The physiologic properties of new technetium-99m-labeled myocardial imaging agents (Tc-99m sestamibi, an isonitrile; and Tc-99m teboroxime, a boronic acid adduct of technetium dioxime) are discussed and compared to thallium-201 (Tl-201). Studies with isolated hearts, subcellular fractions and cell cultures indicate that Tc-99m sestamibi, Tc-99m teboroxime and Tl-201 do not share common transport or sequestration mechanisms. Although peak Tc-99m sestamibi myocardial extraction over time is about half that of Tl-201 at equivalent coronary blood flows, the amount of Tc-99m sestamibi that remains in the heart is similar to that of Tl-201 because of its higher retention efficiency. The high retention efficiency for Tc-99m sestamibi also results in minimal redistribution. In contrast, Tc-99m teboroxime myocardial extraction is higher than that of Tl-201, but its retention is less efficient, resulting in relatively rapid washout characteristics which may quickly result in tracer redistribution. During reperfusion after a no-flow period, Tc-99m sestamibi extraction and retention increase, but for Tc-99m teboroxime and Tl-201 these values tend to decrease. All tracers show adequate transport characteristics for perfusion imaging, and differences in transport and retention should lead to the development of new clinical protocols.27 references.

  14. The neuron-astrocyte-microglia triad in CA3 after chronic cerebral hypoperfusion in the rat: Protective effect of dipyridamole.

    PubMed

    Lana, Daniele; Ugolini, Filippo; Melani, Alessia; Nosi, Daniele; Pedata, Felicita; Giovannini, Maria Grazia

    2017-10-01

    We investigated the quantitative and morphofunctional alterations of neuron-astrocyte-microglia triads in CA3 hippocampus, in comparison to CA1, after 2 Vessel Occlusion (2VO) and the protective effect of dipyridamole. We evaluated 3 experimental groups: sham-operated rats (sham, n=15), 2VO-operated rats treated with vehicle (2VO-vehicle, n=15), and 2VO-operated rats treated with dipyridamole from day 0 to day 7 (2VO-dipyridamole, n=15), 90days after 2VO. We analyzed Stratum Pyramidalis (SP), Stratum Lucidum (SL) and Stratum Radiatum (SR) of CA3. 1) ectopic neurons increased in SL and SR of 2VO-vehicle, and 2VO-dipyridamole rats; 2) apoptotic neurons increased in SP of 2VO-vehicle rats and dipyridamole reverted this effect; 3) astrocytes increased in SP, SL and SR of 2VO-vehicle and 2VO-dipyridamole rats; 4) TNF-α expression increased in astrocytes, blocked by dipyridamole, and in dendrites in SR of 2VO-vehicle rats; 5) total microglia increased in SL and SR of 2VO-vehicle and 2VO-dipyridamole rats; 6) triads increased in SR of 2VO-vehicle rats and dipyridamole reverted this effect. Microglia cooperated with astrocytes to phagocytosis of apoptotic neurons and debris, and engulfed ectopic non-fragmented neurons in SL of 2VO-vehicle and 2VO-dipyridamole rats, through a new mechanism called phagoptosis. CA3 showed a better adaptive capacity than CA1 to the ischemic insult, possibly due to the different behaviour of astrocytes and microglial cells. Dipyridamole had neuroprotective effects. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Reduced coronary flow and resistance reserve in primary scleroderma myocardial disease

    SciTech Connect

    Nitenberg, A.; Foult, J.M.; Kahan, A.; Perennec, J.; Devaux, J.Y.; Menkes, C.J.; Amor, B.

    1986-08-01

    The maximum coronary vasodilator capacity after intravenous dipyridamole (0.14 mg X kg-1 X min-1 X 4 minutes) was studied in seven patients with primary scleroderma myocardial disease and compared to that of seven control subjects. Hemodynamic data and left ventricular angiographic data were not different in the two groups. The coronary flow reserve was evaluated by the dipyridamole/basal coronary sinus blood flow ratio (D/B CSBF) and the coronary resistance reserve by the dipyridamole/basal coronary resistance ratio (D/B CR). Coronary reserve was greatly impaired in the group with primary scleroderma myocardial disease: D/B CSBF was lower than in the control group (2.54 +/- 1.37 vs 4.01 +/- 0.56, respectively; p less than 0.05) and D/B CR was higher than in the control group (0.47 +/- 0.25 vs 0.23 +/- 0.04, respectively; p less than 0.05). Such a decreased coronary flow and resistance reserve in patients with primary scleroderma myocardial disease was not explained by an alteration of left ventricular function. It may be an important contributing factor in the pathogenesis of primary scleroderma myocardial disease.

  16. Clinical trials in thrombosis: secondary prevention of myocardial infarction.

    PubMed

    Klimt, C R; Doub, P H; Doub, N H

    1976-02-29

    Numerous in vivo and in vitro experiments, investigating the inhibition of platelet aggregation and the prevention of experimentally-induced thrombosis, suggest that anti-platelet drugs, such as aspirin or the combination of aspirin, and dipyridamole or sulfinpyrazone, may be effective anti-thrombotic agents in man. Since 1971, seven randomized prospective trials and two case-control studies have been referenced in the literature or are currently being conducted, which evaluate the effects of aspirin, sulfinpyrazone, or dipyridamole in combination with aspirin in the secondary prevention of myocardial infarction. A critical review of these trials indicates a range of evidence from no difference to a favorable trend that anti-platelet drugs may serve as anti-thrombotic agents in man. To date, a definitive answer concerning the therapeutic effects of these drugs in the secondary prevention of coronary heart disease is not available.

  17. Physical training of the patients with coronary heart disease: noninvasive strategies for the evaluation of its effects on the oxygentransport system and myocardial ischemia.

    PubMed

    Doba, N; Shukuya, M; Yoshida, H; Inagaki, M; Inaji, J; Hinohara, S

    1990-11-01

    To clarify the central effects of physical training on patients with coronary heart disease, 81 subjects were selected for the present study. Evaluations of the oxygen transport system function were performed according to the definition proposed by Bruce and others in terms of FAI (functional aerobic impairment), LVI (left ventricular impairment) or MRI (myocardial reserve impairment), CRI (chronotropic reserve impairment) and PCI (peripheral circulatory impairment). Remarkable improvement in left ventricular impairment was found in those patients with single vessel disease or those who experienced disappearance of chest pain after the completion of the program. In another series of study on myocardial perfusion performed on 11 patients with coronary heart disease, improvement in ischemia was also demonstrated in 7 of 8 patients who revealed redistribution pattern in 201TL exercise stress images specifying myocardial ischemia. In conclusion, exercise training could induce improvements not only the left ventricular functions characterized by increased maximal pressure rate product and maximal heart rate, but also in myocardial ischemia. Further studies are needed to specify its effects, since natural progression or regression of the disease process itself may influence the results.

  18. Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging: A new marker of triple-vessel disease

    SciTech Connect

    Takeishi, Y.; Tono-oka, I.; Ikeda, K.; Komatani, A.; Tsuiki, K.; Yasui, S. )

    1991-02-01

    To investigate the significance and mechanism of dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging, we performed both dipyridamole thallium-201 imaging and dipyridamole radionuclide angiography on 83 patients with known angiograms. The dipyridamole/delayed ratio of the left ventricular dimension from the thallium-201 image was defined as the left ventricular dilatation ratio (LVDR). An LVDR greater than the mean + two standard deviations in patients without coronary artery disease was defined as abnormal. Twenty-two of 83 patients showed an abnormal LVDR, and 18 of the 22 patients (82%) had triple-vessel disease. By defect and washout analysis, the sensitivity and specificity for correctly identifying the patients as having triple-vessel disease was 72% and 76%, respectively, whereas LVDR had a sensitivity of 72% and a specificity of 93%. When LVDR was used in combination with the defect and washout criteria, sensitivity increased to 84% without a loss of specificity. In those 22 patients with abnormal LVDRs, end-diastolic volume measured by radionuclide angiography did not change after dipyridamole infusion. Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging reflected relative subendocardial hypoperfusion induced by dipyridamole rather than actual chamber enlargement. The LVDR was moderately sensitive and highly specific for triple-vessel disease and provided complementary information to dipyridamole thallium-201 imaging.

  19. Photo-immobilization of dipyridamole (Persantin) at the surface of polyurethane biomaterials: reduction of in-vitro thrombogenicity.

    PubMed

    Aldenhoff, Y B; Blezer, R; Lindhout, T; Koole, L H

    1997-01-01

    Dipyridamole is a well-known vasodilator and a powerful inhibitor of activation and aggregation of blood platelets. Moreover, dipyridamole is essentially non-toxic. The drug is used extensively in clinical anti-coagulation regimes, for example pre- and post-coronary angioplasty procedures. Recently, we have found that photochemical, covalent coupling of dipyridamole to polyurethane surfaces leads to improved thromboresistance in vitro. This phenomenon is now studied in more detail. Both qualitative and more quantitative biochemical experiments were performed in order to characterize the in vitro blood compatibility of a set of polyurethane surfaces onto which dipyridamole was immobilized. First, scanning electron microscopy was used to examine the morphology of platelets which adhered during incubation with platelet-rich plasma. These experiments showed that immobilization of dipyridamole leads to a clearly decreased number of adherent platelets and to a largely diminished propensity of the surface to activate adherent platelets. Secondly, an in vitro thrombogenicity assay was run. These experiments showed that the thromboresistance increased with increasing surface density of immobilized dipyridamole. A short spacer chain separating dipyridamole from the polymer surface, was found to improve the thromboresistance further. Such a spacer chain apparently increases the efficacy of the immobilized drug. Collectively, the present results further substantiate the idea that dipyridamole retains its inhibitory activity with respect to activation and aggregation of blood platelets, when the compound is covalently attached to a polymer surface. The possible utility of these findings with respect to the development of an artificial blood vessel prosthesis is discussed briefly.

  20. The clinical impact of perfusion scintigraphy with dipyridamole

    SciTech Connect

    Schechtmann, N.; Dae, M.; Lanzer, P.; Sajardo, L.; Faulkner, D.; Botvinick, E.

    1984-01-01

    In order to assess their clinical impact, the authors analyzed perfusion scintigrams (PS) with dipyridamole (D) and the resultant clinical management in 41 consecutive patients (PTS). Population mean age was 67, with 22 males and represented 14% of those having PS. Fifteen PTS had rest chest pain of unknown cause and 26 PTS had pain typical or suggestive of angina but couldn't undergo dynamic stress due to claudication, arthritis, amputation, stroke, recent surgery or other disability. Four PTS were studies for surgical clearance, 3 following angiography to assess coronary pathophysiology and 9 had prior negative or equivocal stress PS at suboptimal levels. Among 18 PTS with reversible scintigraphic abnormalities, 10 underwent subsequent catheterization, with successful CABG in 7, PTCA in 1, aggressive medical treatment of ischemia in 11, and 2 had noncoronary surgery delayed. One PT with associated extensive fixed abnormalities underwent CABG and died late in heart failure. Among 23 PTS without significant scintigraphic reversibility, 8 with normal studies were discharged, 3 went on to uncomplicated noncardiac surgery and 11 PTS, 9 with dilated cardiomyopathy, were managed without therapeutic change. D infusion was uncomplicated and related findings on PS correlated well with coronary angiography, where available in 19 of 20 PTS. PS with D: 1) is safe; 2) correlates closely with coronary anatomy; and 3) adds unique, important pathophysiologic information to clinical evaluation and impacts strongly on the management of a large number of PTS with known or suspected coronary disease.

  1. Development and characterization of cross-linked poly(malate) microspheres with dipyridamole.

    PubMed

    Yoncheva, K; Miloshev, S; Belcheva, N; Lambov, N

    2001-09-11

    Biodegradable cross-linked microspheres containing up to 63 wt.% of the active substance were obtained in a polycondensation process between D,L-malic acid and the tetrahydroxy compound dipyridamole. The in vitro release mechanism from biodegradable cross-linked microspheres has been studied. It was found that dipyridamole was released due to two-step hydrolysis of the ester bonds of the network. Initially, the only product of the hydrolytic degradation was found to be an oligomeric ester fraction with M(w)=1000 Da. The release of the free drug started after 8 days due to a further hydrolysis of the oligomers in solution. It was found that blood plasma enzymes in rats did not affect the hydrolytic processes. Biodegradable poly(malate) microspheres containing an anti-aggregating agent dipyridamole can be considered as a novel drug delivery system for a prolonged period of time implying a future parenteral application.

  2. Changes in plasma lipid composition induced by coconut oil. Effects of dipyridamole.

    PubMed

    García-Fuentes, E; Gil-Villarino, A; Zafra, M F; García-Peregrín, E

    2002-03-01

    The comparative effects of 10-20% coconut oil feeding on fatty acid composition of the main lipid classes of chick plasma have been studied with and without simultaneous treatment with dipyridamole in order to clarify the hypolipidemic role of this drug. Coconut oil drastically increased the percentages of lauric and myristic acids in free fatty acid and triacylglycerol fractions, whereas these changes were less pronounced in phospholipids and cholesterol esters. The percentage of arachidonic acid was higher in plasma phospholipids than in the other fractions and was significantly decreased by coconut oil feeding. Linoleic acid, the main fatty acid of cholesterol esters, was drastically increased by coconut oil feeding. Changes induced by the simultaneous administration of dipyridamole were more pronounced in the phospholipids and cholesterol esters than in the other fractions. The fall observed in linoleic acid levels after dipyridamole treatment may be of interest for a lower production of its derived eicosanoids, especially in plasma phospholipids and cholesterol esters.

  3. Distribution of dipyridamole in blood components among post-stroke patients treated with extended release formulation.

    PubMed

    Serebruany, Victor; Sabaeva, Elena; Booze, Christopher; Atar, Oliver D; Eisert, Christian; Hanley, Dan

    2009-09-01

    Extended release dipyridamole (ERD) is widely used in patients after ischaemic stroke; however, the ability of this antithrombotic agent to be stored in different blood cells has never been explored in post-stroke patients. We hypothesised that since ERD is known to be highly lipophilic, the drug may be present not only in plasma, but also accumulated in platelets, leukocytes, and erythrocytes. Fifteen patients after documented ischaemic stroke were treated with Aggrenox (ERD and low-dose aspirin combination) BID for 30 days, and 12 of them completed the study. ERD concentrations in blood cells and platelet-poor plasma were measured by spectrofluorimetry at Baseline, Day 14, and Day 30 after the initiation of therapy. The background level of spectrofluorometry readings differs slightly among the blood components (132-211 ng/ml) due to the differences in the preparation of samples and cell isolation techniques. As expected, two weeks of ERD therapy produced steady-state plasma concentration of dipyridamole already at Day 14 (1,680 +/- 542 ng/ ml), followed by a slight not significant decrease at one month (1,619 +/- 408 ng/ml). Two weeks of therapy was sufficient to achieve a consistent dipyridamole accumulation in erythrocytes (361 +/- 43 ng/ml), but not in platelets (244 +/- 78 ng/ml), or leukocytes (275 +/- 49 ng/ml). In fact, white blood cells continued dipyridamole intake beyond 14 days period, and this increase (398 +/- 66 ng/ml) was significant (p = 0.02) at 30 days. Treatment with ERD in post-stroke patients resulted not only in achievement of therapeutic plasma dipyridamole concentrations, but also deposition of the drug in erythrocytes and leukocytes, but not in platelets. If confirmed, these data will affect our better understanding of dipyridamole pleiotropy, and may explain long-term benefit of ERD formulation.

  4. Prevalence and clinical significance of painless ST segment depression during early postinfarction exercise testing

    SciTech Connect

    Gibson, R.S.; Beller, G.A.; Kaiser, D.L.

    1987-03-01

    In a recent study of 190 survivors of acute myocardial infarction, the authors sought to determine whether exercise-induced painless ST segments depression indicates residual myocardial ischemia, as defined by /sup 201/Tl scintigraphic criteria. 2 weeks after uncomplicated myocardial infarction, and whether quantitative /sup 201/Tl imaging enhances the prognostic value of such an exercise electrocardiographic response.

  5. Quantitative analysis of planar technetium-99m-sestamibi myocardial perfusion images using modified background subtraction

    SciTech Connect

    Koster, K.; Wackers, F.J.; Mattera, J.A.; Fetterman, R.C. )

    1990-08-01

    Standard interpolative background subtraction, as used for thallium-201 ({sup 201}Tl), may create artifacts when applied to planar technetium-99m-Sestamibi ({sup 99m}Tc-Sestamibi) images, apparently because of the oversubtraction of relatively high extra-cardiac activity. A modified background subtraction algorithm was developed and compared to standard background subtraction in 16 patients who had both exercise-delayed {sup 201}Tl and exercise-rest {sup 99m}Tc-Sestamibi imaging. Furthermore, a new normal data base was generated. Normal {sup 99m}Tc-Sestamibi distribution was slightly different compared to {sup 201}Tl. Using standard background subtraction, mean defect reversibility was significantly underestimated by {sup 99m}Tc-Sestamibi compared to {sup 201}Tl (2.8 +/- 4.9 versus -1.8 +/- 8.4, p less than 0.05). Using the modified background subtraction, mean defect reversibility on {sup 201}Tl and {sup 99m}Tc-Sestamibi images was comparable (2.8 +/- 4.9 versus 1.7 +/- 5.2, p = NS). We conclude, that for quantification of {sup 99m}Tc-Sestamibi images a new normal data base, as well as a modification of the interpolative background subtraction method should be employed to obtain quantitative results comparable to those with {sup 201}Tl.

  6. Determination of dipyridamole in pharmaceutical preparations using square wave voltammetry.

    PubMed

    de Toledo, Renata Alves; Castilho, Marilza; Mazo, Luiz Henrique

    2005-01-04

    An analytical methodology using square wave voltammetry (SWV) at a hanging mercury drop electrode (HMDE) was developed for the quantitative determination of dipyridamole (DIP), a drug used for the treatment of several cardiovascular diseases, in pharmaceutical tablets and injections of Persantin in phosphate buffer (pH 3.0; 0.1M). After optimization of the parameters for SWV, analytical curves were obtained for application in the range of 1.28 x 10(-6)M to 7.02 x 10(-6)M. It was found a detection limit (DL) of 1.88 x 10(-8)M (9.50 ng/ml). The repeatability and the reproducibility of the method were determinated by successive measurements of DIP solutions on the range of the analytical curve with a coefficient variation of 0.97% (n=5) and 1.15%, respectively. The apparent recoveries were obtained by the IUPAC recommended procedure using the second reduction peak. Recoveries obtained by SWV were compared with the UV-vis spectrophotometric method. It was found that the determination of DIP in Persantin tablets gave a mean value of 75.6+/-0.4 mg (100.8%) and 68.9+/-0.3 mg (91.8%) for SWV and UV-vis spectrophotometry, respectively. In the case of injections, it was found 10.4+/-0.1 mg (103.4%) and 9.9+/-0.2 mg (99.9%) for SWV and UV-vis spectrophotometry. Both apparent recoveries for the two types of formulations are in good accordance with the declared value of 75 mg (tablets) and 10 mg (injections).

  7. Intravenous dipyridamole thallium-201 SPECT imaging in patients with left bundle branch block

    SciTech Connect

    Rockett, J.F.; Wood, W.C.; Moinuddin, M.; Loveless, V.; Parrish, B. )

    1990-06-01

    Tl-201 exercise imaging in patients with left bundle branch block (LBBB) has proven to be indeterminate for significant left anterior descending (LAD) coronary artery stenosis because of the presence of immediate septal perfusion defects with redistribution on delayed images in almost all cases. Tl-201 redistribution occurs regardless of the presence or absence of LAD stenosis. Nineteen patients having LBBB were evaluated with dipyridamole Tl-201 SPECT. Fourteen of these subjects had normal dipyridamole Tl-201 SPECT imaging. Three patients had normal coronary angiograms. None of the remaining 11 patients with normal dipyridamole Tl-201 SPECT images was found to have clinical coronary artery disease in a 5-11 month follow-up period. Five patients had abnormal septal perfusion. Four underwent coronary angiography. One had a significant LAD stenosis. The single patient with septal redistribution who refused to undergo coronary angiography died shortly thereafter of clinical coronary artery disease. This preliminary work suggests that dipyridamole Tl-201 SPECT may be more useful for excluding LAD stenosis in patients with LBBB than Tl-201 exercise imaging.

  8. Regadenoson pharmacologic rubidium-82 PET: a comparison of quantitative perfusion and function to dipyridamole.

    PubMed

    Cullom, S James; Case, James A; Courter, Staci A; McGhie, A Iain; Bateman, Timothy M

    2013-02-01

    Dipyridamole is used for stress (82)rubidium chloride ((82)RbCl) PET because of its long hyperemic duration. Regadenoson has advantages of a fixed dose and favorable symptom profile, but its mean maximal hyperemia is only 2.3 minutes. To determine its suitability for (82)RbCl PET, we imaged subjects using a regadenoson protocol based on its hyperemic response and compared the images in the same subjects having dipyridamole PET. In 32 subjects (23 M), we assessed visually by blinded interpretation and quantitatively compared summed stress and difference scores, total perfusion deficit (TPD), LVEF, LV volumes, and change in stress-rest function. Linear correlation and Bland-Altman analysis of the paired measurements were applied for evaluation of differences. Paired t test and Pearson's correlation were applied for testing of significance. The images were interpreted the same by visual assessment. Twenty-six (26) subjects had reversible defects; by quantitation the SSS was 12.9 ± 7.0 and 14.1 ± 6.4 (P = .23) and SDS was 7.0 ± 6.8 versus 7.6 ± 6.2 (P = .40) for dipyridamole and regadenoson, respectively. Six (6) subjects had <5% likelihood of CAD and were normal by both. All paired measurements showed a high positive correlation between regadenoson and dipyridamole; stress segmental perfusion Reg = 0.93Dip + 4.4, r = 0.88; TPD Reg = 0.94Dip + 0.41, r = 0.93; LVEF Reg = 0.92Dip + 4.7, r = 0.95; stress minus rest LVEF Reg = 0.87Dip - 0.99, r = 0.82. Regadenoson stress (82)RbCl PET perfusion defect and cardiac function measurements are visually and quantitatively equivalent to dipyridamole studies and can be obtained with the clinical advantages of regadenoson.

  9. Nephroprotective role of dipyridamole in diabetic nephropathy: Effect on inflammation and apoptosis.

    PubMed

    Elsherbiny, Nehal M; Al-Gayyar, Mohammed M H; Abd El Galil, Khaled H

    2015-12-15

    Inflammation plays significant roles in developing diabetic nephropathy (DN). Adenosine, natural purine nucleoside, acts as potent endogenous anti-inflammatory agent. Extracellular adenosine usually disappears quickly due to rapid uptake into adjacent cells. In this regard; we investigated putative reno-protective effects of dipyridamole, nucleoside transport inhibitor, by exploring its anti-inflammatory mechanisms in-vivo and in-vitro. Daily 6mg/kg/day dipyridamole was given to six-weeks streptozotocin-induced diabetic rats over two-week period in presence/absence of 10mg/kg/day CGS15943, potent non selective adenosine receptors antagonist. Histological changes were assessed in kidney sections. Gene and protein expression of interleukin (IL)-1β, IL-10, IL-18, tumor necrosis factor (TNF)-α and intercellular adhesion molecule (ICAM)-1 was measured. Activation of apoptotic pathway was demonstrated by measuring the activity of caspase-3/8/9 and activation of c-Jun NH2-terminal kinases (JNK)-mitogen-activated-protein kinase (MAPK). In addition, all markers were measured in human mesangial cells cultured in high glucose. Diabetes induced marked changes in the glomerular and tubular structure including focal glomerulosclerosis with marked shrinkage of some glomerular tufts. Diabetes resulted in enhanced production of IL-1β, IL-18, TNF-α and ICAM-1 associated with reduced IL-10 protein level, leading to activation of caspases-3/8/9 and pJNK/JNK in-vivo and in-vitro. Dipyridamole treatment restored diabetes-induced reduction in adenosine levels and resulted in mild glomerular effects and vacuolation of tubular epithelium. Dipyridamole reduced the adhesion molecule, ICAM-1, and restored the normal balance between pro- and anti-inflammatory cytokines in-vivo and in-vitro. Dipyridamole prevented the progression of DN by elevating endogenous levels of protecting adenosine, leading to reduction in inflammation and intrinsic apoptosis. Copyright © 2015 Elsevier Inc. All

  10. Long-term prognostic value of preoperative dipyridamole thallium imaging and clinical indexes in patients with diabetes mellitus undergoing peripheral vascular surgery.

    PubMed

    Cohen, M C; Curran, P J; L'Italien, G J; Mittleman, M A; Zarich, S W

    1999-04-01

    The objective of this study is to assess the prognostic impact of preoperative dipyridamole thallium imaging and clinical variables on the long-term outcome of diabetic patients undergoing peripheral vascular surgery. Complete follow-up was obtained in 101 consecutive patients with diabetes mellitus undergoing routine dipyridamole thallium scintigraphy before vascular surgery (mean 4.2 +/- 3.2 years, range 1 month to 11 years). Low risk was defined by diabetes alone with a normal resting electrocardiogram. High risk was defined as a history of angina, myocardial infarction, congestive heart failure, or resting electrocardiogram abnormalities. There were 71 deaths in 98 patients discharged alive from the hospital (median survival 4.4 years). Age, the presence of resting electrocardiogram abnormalities, and an abnormal thallium scan were independent predictors of late death. After adjusting for age >70 years and thallium abnormalities, high-risk patients had a death rate 4.8 times (95% confidence interval 1.7 to 13.4, p <0.002) greater than low-risk patients. The presence of >2 reversible thallium defects was useful in further risk stratification of both low- and high-risk patients. Low-risk patients with >2 reversible defects had a median survival of 4.0 years compared with 9.4 years in those with < or =2 reversible defects (p <0.001). Similarly, high-risk patients with < or =2 reversible defects had an intermediate median survival rate of 4.7 years compared with 1.8 years in the group with >2 reversible defects (p <0.001). Therefore, advanced age and the presence of resting electrocardiographic or thallium abnormalities identifies a subset of diabetic patients with a poor long-term outcome after vascular surgery. Combined clinical and thallium variables may identify a population in whom intensive medical or surgical interventions may be warranted to reduce both perioperative and late cardiac events.

  11. Nuclear myocardial perfusion imaging using thallium-201 with a novel multifocal collimator SPECT/CT: IQ-SPECT versus conventional protocols in normal subjects.

    PubMed

    Matsuo, Shinro; Nakajima, Kenichi; Onoguchi, Masahisa; Wakabayash, Hiroshi; Okuda, Koichi; Kinuya, Seigo

    2015-06-01

    A novel multifocal collimator, IQ-SPECT (Siemens) consists of SMARTZOOM, cardio-centric and 3D iterative SPECT reconstruction and makes it possible to perform MPI scans in a short time. The aims are to delineate the normal uptake in thallium-201 ((201)Tl) SPECT in each acquisition method and to compare the distribution between new and conventional protocol, especially in patients with normal imaging. Forty patients (eight women, mean age of 75 years) who underwent myocardial perfusion imaging were included in the study. All patients underwent one-day protocol perfusion scan after an adenosine-stress test and at rest after administering (201)Tl and showed normal results. Acquisition was performed on a Symbia T6 equipped with a conventional dual-headed gamma camera system (Siemens ECAM) and with a multifocal SMARTZOOM collimator. Imaging was performed with a conventional system followed by IQ-SPECT/computed tomography (CT). Reconstruction was performed with or without X-ray CT-derived attenuation correction (AC). Two nuclear physicians blinded to clinical information interpreted all myocardial perfusion images. A semi-quantitative myocardial perfusion was analyzed by a 17-segment model with a 5-point visual scoring. The uptake of each segment was measured and left ventricular functions were analyzed by QPS software. IQ-SPECT provided good or excellent image quality. The quality of IQ-SPECT images without AC was similar to those of conventional LEHR study. Mid-inferior defect score (0.3 ± 0.5) in the conventional LEHR study was increased significantly in IQ-SPECT with AC (0 ± 0). IQ-SPECT with AC improved the mid-inferior decreased perfusion shown in conventional images. The apical tracer count in IQ-SPECT with AC was decreased compared to that in LEHR (0.1 ± 0.3 vs. 0.5 ± 0.7, p < 0.05). The left ventricular ejection fraction from IQ-SPECT was significantly higher than that from the LEHR collimator (p = 0.0009). The images of IQ-SPECT acquired in a

  12. Effect of {beta}{sub 1} adrenergic receptor blockade on myocardial blood flow and vasodilatory capacity

    SciTech Connect

    Boettcher, M.; Czernin, J.; Sun, K.

    1997-03-01

    The {beta}{sub 1} receptor blockade reduces cardiac work and may thereby lower myocardial blood flow (MBF) at rest. The effect of {beta}{sub 1} receptor blockade on hyperemic MBF is unknown. To evaluate the effect of selective {beta}{sub 1} receptor blockade on MBF at rest and during dipyridamole induced hyperemia, 10 healthy volunteers (8 men, 2 women, mean age 24 {+-} 5 yr) were studied using {sup 13}N-ammonia PET (two-compartment model) under control conditions and again during metoprolol (50 mg orally 12 hr and 1 hr before the study). The resting rate pressure product (6628 {+-} 504 versus 5225 {+-} 807) and heart rate (63 {+-} 6-54 {plus_minus} 5 bpm) declined during metoprolol (p < 0.05). Similarly, heart rate and rate pressure product declined from the baseline dipyridamole study to dipyridamole plus metoprolol (p < 0.05). Resting MBF declined in proportion to cardiac work by approximately 20% from 0.61 {+-} 0.09-0.51 {+-} 0.10 ml/g/min (p < 0.05). In contrast, hyperemic MBF increased when metoprolol was added to dipyridamole (1.86 {plus_minus} 0.27 {+-} 0.45 ml/g/min; p<0.05). The decrease in resting MBF together with the increase in hyperemic MBF resulted in a significant increase in the myocardial flow reserve during metoprolol (3.14 {+-} 0.80-4.61 {+-} 0.68; p<0.01). The {beta}{sub 1} receptor blockade increases coronary vasodilatory capacity and myocardial flow reserve. However, the mechanisms accounting for this finding remain uncertain. 32 refs., 2 figs., 2 tabs.

  13. Identification of Angiogenesis Rich-Viable Myocardium using RGD Dimer based SPECT after Myocardial Infarction

    PubMed Central

    Lee, Min Su; Park, Hyun Soo; Lee, Byung Chul; Jung, Jae Ho; Yoo, Jung Sun; Kim, Sang Eun

    2016-01-01

    Cardiac healing after myocardial ischemia is a complex biological process. Advances in understanding of wound healing response have paved the way for clinical testing of novel molecular imaging to improve clinical outcomes. A key factor for assessing myocardial viability after ischemic injury is the evaluation of angiogenesis accompanying increased expression of integrin αvβ3. Here, we describe the capability of an αvβ3 integrin-targeting SPECT agent, 99mTc-IDA-D-[c(RGDfK)]2, for identification of ischemic but viable myocardium, i.e., hibernating myocardium which is crucial to predict functional recovery after revascularization, the standard care of cardiovascular medicine. In vivo SPECT imaging of rat models with transient coronary occlusion showed significantly high uptake of 99mTc-IDA-D-[c(RGDfK)]2 in the ischemic region. Comparative measurements with 201Tl SPECT and 18F-FDG PET, then, proved that such prominent uptake of 99mTc-IDA-D-[c(RGDfK)]2 exactly matched the hallmark of hibernation, i.e., the perfusion-metabolism mismatch pattern. The uptake of 99mTc-IDA-D-[c(RGDfK)]2 was non-inferior to that of 18F-FDG, confirmed by time-course variation analysis. Immunohistochemical characterization revealed that an intense signal of 99mTc-IDA-D-[c(RGDfK)]2 corresponded to the vibrant angiogenic events with elevated expression of αvβ3 integrin. Together, these results establish that 99mTc-IDA-D-[c(RGDfK)]2 SPECT can serve as a sensitive clinical measure for myocardial salvage to identify the patients who might benefit most from revascularization. PMID:27283041

  14. Noninvasive assessment of changes in myocardial perfusion and ventricular performance following exercise training

    SciTech Connect

    Tubau, J.; Witztum, K.; Froelicher, V.; Jensen, D.; Atwood, E.; McKirnan, M.D.; Reynolds, J.; Ashburn, W.

    1982-08-01

    Seventeen coronary patients (CAD) underwent /sup 201/Tl treadmill and radionuclide (RNV) ejection fraction supine bicycle testing before and after 5.6 +/- 1.6 (mean +/- SD) months of an exercise program. Thallium data were assessed both using analog images and a computerized circumferential profile technique. Patients exercised on the treadmill to a higher workload after the exercise program, but achieved a similar pressure-rate product. When interpreting the analog thallium images, only 50% agreement was obtained for the assessment of changes in myocardial perfusion (pre/post-training). The computer technique, however, had low inter-intraobserver variability (6%) and better agreement (90.5%). Using the circumferential profile method, five patients improved (a total of 11 regions) and one patient worsened (with two regions). Before the exercise program, the ejection fraction (EF) response to supine bike exercise was normal (an increase greater than 11%) in four, flat in seven, and severely abnormal (a decrease of more than 4%) in six patients. After the exercise program, even though achieving similar or higher pressure-rate products, six patients improved their EF response, nine did not change, and two worsened. Of the five patients who improved their thallium images, one improved his EF response, two remained normal, and two did not change. One patient worsened both his thallium study and the EF response after the exercise program. Changes in thallium exercise images and the EF response to supine exercise occurred in our patients after an exercise program, but were not always concordant. Indeed, of five patients with exercise-induced ischemic ST changes before and after training, the EF response improved in three whereas myocardial perfusion was unchanged. Reasons for this lack of agreement are discussed, and have been considered in the planning of a randomized trial of the effects of an exercise program on myocardial perfusion and function.

  15. Slowing of proton transport processes in the structure of bacterial reaction centers and bacteriorhodopsin in the presence of dipyridamole.

    PubMed

    Knox, P P; Lukashev, E P; Mamedov, M D; Semenov, A Y; Seifullina, N H; Zakharova, N I

    2000-02-01

    Dipyridamole, 2,6-bis(diethanolamino)-4,8-dipiperidinopyrimido(5, 4-d)pyrimidine, is employed in clinical practice as a vasodilator. It can also inhibit a specific membrane protein (glycoprotein P) which pumps anticancer drugs out of tumor cells. Dipyridamole (10-4 M) markedly slows down the kinetics of the electrogenic phase of the photoelectric response in Rhodobacter sphaeroides chromatophores. This phase is due to proton transfer from the external medium to the secondary quinone acceptor in the reaction center. In purple membranes of bacterium Halobacterium salinarium containing bacteriorhodopsin dipyridamole (in its charged state) significantly slowed the kinetics of proton transfer from the primary donor, Asp-96 (in membranes from bacteria of wild type), or from the external medium (in D96N mutant) to the Schiff base. It is suggested that dipyridamole can influence the structural-dynamic state of membrane proteins including modification of the structure of their hydrogen bonds involved in proton-transport processes.

  16. "ECG variability contour" method reveals amplitude changes in both ischemic patients and normal subjects during Dipyridamole stress: a preliminary report.

    PubMed

    Dori, Guy; Gershinsky, Michal; Ben-Haim, Simona; Lewis, Basil S; Bitterman, Haim

    2011-11-01

    To detect and quantify consistent ECG amplitude changes, the "ECG variability contour" (EVC) method was proposed. Using this method we investigated amplitude changes in subjects undergoing myocardial perfusion imaging (MPI) with Dipyridamole (Dp). Fifty-three patients having reversible perfusion defects and 19 normal subjects (NS) who were free of: perfusion defects on their MPI, standard ST-T changes during Dp stress, and a negative clinical follow up. Mean ∏¹(<∏¹>) was similar for the NS and patient group (6.2 ± 6.1 vs. 6.3 ± 6.2, P = 0.95). <∏¹> was 4.6 ± 3.0 in patients not having ST-T changes during Dp stress (n = 42), whereas in patients having ST-T changes (n = 11) it was 13.1 ± 10.2 (P < 0.001). For both groups <∏(QRS)> was smaller than <∏(ST)>, which in turn was smaller than <∏(T)>. The values of <∏(QRS)>, <∏(ST)>, and <∏(T)> for the NS, patients without and with ST-T changes were: 26.8 ± 28.6, 42.6 ± 41.8, 44.9 ± 36.5; 19.6 ± 20.8, 26.4 ± 31.4, 38.7 ± 27.3; 51.0 ± 30.0, 71.0 ± 36.8, 75.1 ± 20.9, respectively (P < 0.05 for all comparisons of patients with versus without ST-T changes). This study showed that Dp stress, with or without hypoperfusion, had a clear effect on myocyte electrophysiology, expressed by consistent ECG amplitude changes, detected by the EVC method. The EVC method did not distinguish between NS and patients in this clinical setting.

  17. Glucose and erythrocyte ATP: distinctive effects of dipyridamole and of ticlopidine.

    PubMed

    Solvay, H; Kahn, M; Garreyn, S; Cloarec, M; Sneppe, R; Schram, E; Fenollar, J V

    1987-11-01

    This experiment suggests the following points: 1. Erythrocytes in control patients and in atherosclerosis patients seem to have a variable grade of affinity for adenosine and for plasma glucose. This variable grade seems to fix the level of the adenosine triphosphate (ATP) reserves and induces the erythrocytes' deformability. 2. The drop in the level of ATP reserves that induces the poor deformability of the erythrocytes in atherosclerosis patients would appear to be caused by two consecutive shortages: first a shortage that seems to be related to a deficiency of erythrocyte adenosine as the ATP shortage disappears with dipyridamole treatment and then a shortage induced by the lack of erythrocyte glucose and suppressed by the addition of ticlopidine to the dipyridamole treatment.

  18. Changes in transmural distribution of myocardial perfusion assessed by quantitative intravenous myocardial contrast echocardiography in humans

    PubMed Central

    Fukuda, S; Muro, T; Hozumi, T; Watanabe, H; Shimada, K; Yoshiyama, M; Takeuchi, K; Yoshikawa, J

    2002-01-01

    Objective: To clarify whether changes in transmural distribution of myocardial perfusion under significant coronary artery stenosis can be assessed by quantitative intravenous myocardial contrast echocardiography (MCE) in humans. Methods: 31 patients underwent dipyridamole stress MCE and quantitative coronary angiography. Intravenous MCE was performed by continuous infusion of Levovist. Images were obtained from the apical four chamber view with alternating pulsing intervals both at rest and after dipyridamole infusion. Images were analysed offline by placing regions of interest over both endocardial and epicardial sides of the mid-septum. The background subtracted intensity versus pulsing interval plots were fitted to an exponential function, y = A (1 − e−βt), where A is plateau level and β is rate of rise. Results: Of the 31 patients, 16 had significant stenosis (> 70%) in the left anterior descending artery (group A) and 15 did not (group B). At rest, there were no differences in the A endocardial to epicardial ratio (A-EER) and β-EER between the two groups (mean (SD) 1.2 (0.6) v 1.2 (0.8) and 1.2 (0.7) v 1.1 (0.6), respectively, NS). During hyperaemia, β-EER in group A was significantly lower than that in group B (1.0 (0.5) v 1.4 (0.5), p < 0.05) and A-EER did not differ between the two groups (1.0 (0.5) v 1.2 (0.4), NS). Conclusions: Changes in transmural distribution of myocardial perfusion under significant coronary artery stenosis can be assessed by quantitative intravenous MCE in humans. PMID:12231594

  19. Biphasic thallium 201 SPECT-imaging for the noninvasive diagnosis of myocardial perfusion abnormalities in a child with Kawasaki disease--a case report

    SciTech Connect

    Hausdorf, G.; Nienaber, C.A.; Spielman, R.P.

    1988-02-01

    The mucocutaneous lymph node syndrome (Kawasaki disease) is of increasing importance for the pediatric cardiologist, for coronary aneurysms with the potential of thrombosis and subsequent stenosis can develop in the course of the disease. The authors report a 2 1/2-year-old female child in whom, fourteen months after the acute phase of Kawasaki disease, myocardial infarction occurred. Biphasic thallium 201 SPECT-imaging using dipyridamole depicted anterior wall ischemia and inferolateral infarction. This case demonstrates that noninvasive vasodilation-redistribution thallium 201 SPECT-imaging has the potential to predict reversible myocardial perfusion defects and myocardial necrosis, even in small infants with Kawasaki disease.

  20. Adenosine thallium 201 myocardial perfusion scintigraphy

    SciTech Connect

    Verani, M.S. )

    1991-07-01

    Pharmacologic coronary vasodilation as an adjunct to myocardial perfusion imaging has become increasingly important in the evaluation of patients with coronary artery disease, in view of the large number of patients who cannot perform an adequate exercise test or in whom contraindications render exercise inappropriate. Adenosine is a very potent coronary vasodilator and when combined with thallium 201 scintigraphy produces images of high quality, with the added advantages of a very short half-life (less than 10 seconds) and the ability to adjust the dose during the infusion, which may enhance safety and curtail the duration of side effects. The reported sensitivity and specificity of adenosine thallium 201 scintigraphy for the detection of coronary artery disease are high and at least comparable with imaging after exercise or dipyridamole administration. 23 refs.

  1. Secondary prevention of myocardial infarction with drugs.

    PubMed

    Klimt, C R; Forman, S A

    1983-05-01

    Clinical trials in the field of secondary prevention of myocardial infarctions are reviewed, with emphasis on those studies that were randomized and included at least 100 patients. Standardized total mortality data, when available, are provided. Five groups of drugs are reviewed: 1) antiarrhythmic drugs, including studies of phenytoin, tocainide, mexiletine and aprindine. Important, commonly used drugs in this group, which apparently have not been submitted to clinical trials, include procainamide and lidocaine; 2) lipid-lowering drugs, including estradiol, conjugated equine estrogen, dextrothyroxine, clofibrate and nicotinic acid; 3) anticoagulant drugs, the oldest and most controversial preventive drug measure. In this group, only the oral drug derivatives of indandione or coumarin have been tested, and no appropriate studies of parenteral heparin were found; 4) platelet-active drugs--six studies dealing with aspirin alone, one combining aspirin and dipyridamole, and one study of sulfinpyrazone are reviewed; and 5) beta-adrenergic blocking drugs, including practolol and timolol.

  2. Reduction of indium-111 platelet deposition on Dacron vascular grafts in humans by aspirin plus dipyridamole

    SciTech Connect

    Stratton, J.R.; Ritchie, J.L.

    1986-02-01

    Aspirin plus dipyridamole reduces platelet accumulation on short-term Dacron vascular grafts in man. To determine whether drug inhibition of platelet deposition is sustained on older grafts, we studied 18 men aged 41 to 87 years who had Dacron aortic bifurcation grafts in place a mean of 43.4 months (range 9.8 to 121.0) before and during short-term therapy with aspirin (325 mg tid) plus dipyridamole (75 mg tid). During both the baseline and drug studies, indium-111 (/sup 111/In) platelet deposition was quantitated by two techniques, standard planar imaging performed at 24, 48, and 72 hr after injection of platelets and single photon emission computed tomographic imaging performed at 24 and 72 hr after injection. All analyses were performed in a blinded fashion. On both the planar and tomographic images, platelet accumulation on the graft was quantitated by a graft/blood ratio that compared activity in the graft to simultaneously collected whole blood /sup 111/In platelet activity. Aspirin plus dipyridamole reduced the tomographic graft/blood ratio at 24 hr (20.6 +/- 3.5 vs 17.3 +/- 2.5) (+/-SEM) and at 72 hr (29.0 +/- 4.8 vs 25.0 +/- 4.1) after injection of platelets (p = .02). Dacron vascular grafts. Similarly, the planar graft/blood ratio was reduced at 24 hr (2.7 +/- 0.5 vs 2.4 +/- 0.5), 48 hr (3.7 +/- 0.9 vs 3.1 +/- 0.7), and 72 hr (4.0 +/- 0.9 vs 3.6 +/- 0.8) (p = .04). We conclude that aspirin (325 mg tid) plus dipyridamole (75 mg tid) reduces platelet accumulation on long-term Dacron vascular grafts.

  3. Noninvasive identification of significant narrowing of the left main coronary artery by dipyridamole thallium scintigraphy

    SciTech Connect

    Chikamori, T.; Doi, Y.L.; Yonezawa, Y.; Yamada, M.; Seo, H.; Ozawa, T. )

    1991-08-15

    To evaluate the usefulness of dipyridamole thallium scintigraphy with low-level exercise for the identification of left main (LM) coronary artery disease (CAD), 466 consecutive patients with CAD were studied. Thirty-eight patients (8%) had LM stenosis (diameter narrowing greater than or equal to 50%). The LM scintigraphic pattern was present in 9 of 38 patients with LMCAD and 38 of 428 CAD patients without LMCAD (24 vs 9%; p less than 0.005). This pattern was present in 6 of 9 patients with LMCAD without right CAD and in only 3 of 29 patients with LM and right CAD (67 vs 10%; p = 0.0005). Patients with LMCAD had a higher incidence of premature cessation of low-level exercise (53 vs 21%; p less than 0.0001), chest pain (68 vs 48%; p less than 0.02), blood pressure decrease of greater than or equal to 20 mm Hg (44 vs 16%; p less than 0.002) and greater ST depression (0.17 {plus minus} 0.13 vs 0.06 {plus minus} 0.10 mV; p less than 0.001) during dipyridamole loading than patients without LMCAD. Stepwise discriminant analysis revealed that the LM scintigraphic pattern and markers of ischemia during dipyridamole loading best identified (p less than 0.0001) patients with LMCAD without right CAD (sensitivity 67%, specificity 91%), but this predictability is no better than the LM scintigraphic pattern alone. The combination of clinical markers of ischemia during dipyridamole loading and scintigraphic findings of diffuse slow washout, extensive fixed defects and the LM pattern best identified (p less than 0.0001) patients with LM and right CAD (sensitivity 72%, specificity 80%).

  4. Prognostic impact of stress testing in coronary artery disease

    SciTech Connect

    Severi, S.; Michelassi, C. )

    1991-05-01

    Observational data prospectively collected permit the examination of a complex set of decisions, including the decision not to perform any stress testing. Patients with or without previous myocardial infarction admitted for coronary evaluation and not submitted to any stress testing because of clinical reasons are at a higher risk for subsequent death. For prognostication, no test has been better validated than exercise electrocardiography: it can identify patients at low and high risk for future cardiac events among those without symptoms, with typical chest pain, and with previous myocardial infarction. In patients with triple-vessel disease, the results of exercise also allow those at low and high risk to be recognized. Both exercise radionuclide angiography and {sup 201}Tl scintigraphy (the latter in larger patient populations) have also demonstrated significant prognostic value on patients with or without previous myocardial infarction. Neither one has shown superiority to the other in prognostication. So far, they have been considered the only viable alternatives to exercise electrocardiography stress testing for diagnosis and prognostication. However, their costs limit their extensive application. Preliminary data suggest that intravenous dipyridamole echocardiography can be used for both diagnosis and prognostication of coronary artery disease; moreover, the prognostic information derived from dipyridamole echocardiography testing seems independent of and additive to that provided by exercise electrocardiography. Further prospective studies on larger patient populations are needed to better define the prognostic value of dipyridamole echocardiography testing.47 references.

  5. Myocardial Ischemia

    MedlinePlus

    ... pectoris: Chest pain caused by myocardial ischemia. www.uptodate.com/home. Accessed June 1, 2015. Deedwania PC. Silent myocardial ischemia: Epidemiology and pathogenesis. www.uptodate.com/home. Accessed June 1, 2015. Mann DL, ...

  6. Assay of dipyridamole in human serum using cathodic adsorptive square-wave stripping voltammetry.

    PubMed

    Ghoneim, M M; Tawfik, A; Radi, A

    2002-09-01

    A rapid and sensitive square-wave voltammetric procedure was optimized for the determination of dipyridamole after its adsorption preconcentration onto a hanging mercury drop electrode. The peak current of the first of the two peaks developed for this drug in Britton-Robinson buffer at pH 8.0 has been considered for the present analytical study. An accumulation potential of -1.0 V versus Ag/AgCl/KCl(s), pulse amplitude a =100 mV, scan increment Delta E =10 mV, and frequency f =120 Hz were the optimal experimental parameters. Dipyridamole can be determined in the concentration range of 9.0 x 10(-9) to 5.0 x 10(-6) M using accumulation times of 30-300 s. A detection limit of 4.0 x 10(-11) M was achieved after a 300 s accumulation time. Applicability to serum samples was illustrated. The average recoveries for dipyridamole spiked to serum at 0.25-4.50 micro g ml(-1) were 96.0-102.0%, and the higher standard deviation was 2.9%. A detection limit of 0.06 micro g mL(-1) of serum was obtained.

  7. Formulation and evaluation of gastroretentive floating drug delivery system of dipyridamole.

    PubMed

    Jiang, Huiming; Tian, Rui; Hu, Wenjing; Jia, Yuntao; Yuan, Pei; Wang, Jiayu; Zhang, Liangke

    2015-04-01

    A multiple-unit floating alginate bead drug delivery system with prolonged stomach retention time was developed in this study. The floating alginate beads were prepared by ionic cross-linking method, using CaCO3 as the gas-forming agent. Over 92% of the beads remained floating after 9 h. In order to prepare sustained-release dosage forms of dipyridamole, the solid dispersion technique was applied using a blend of Eudragit L100 and Eudragit RLPO. Afterwards, the solid dispersions of dipyridamole were incorporated into the floating alginate beads. The drug release was modified by changing the ratio of Eudragit RLPO and Eudragit L100 in the solid dispersions. The in vivo results showed that the relative bioavailability of alginate beads was enhanced by approximately 2.52-fold compared with that of the commercial tablet. Therefore, our study illustrated the potential use of floating alginate beads combined with the solid dispersion technique for the delivery of acid-soluble compounds, such as dipyridamole.

  8. A myocardial perfusion imaging system using a multifocal collimator for detecting coronary artery disease: validation with invasive coronary angiography.

    PubMed

    Ogino, Yutaka; Horiguchi, Yoriko; Ueda, Tomohiro; Shiomori, Tomofumi; Kanna, Masahiko; Kawaminami, Tomoko; Iinuma, Naoki; Sudo, Yuta; Morita, Yukiko

    2015-05-01

    Myocardial perfusion imaging (MPI) systems using a multifocal collimator can reduce scan time substantially compared with conventional MPI systems. In this study, we evaluated the diagnostic accuracy of multifocal collimator SPECT/CT in coronary artery disease (CAD) detection by comparing it with coronary artery angiography (CAG). We retrospectively analyzed 50 consecutive patients who had undergone CAG and stress (201)Tl MPI multifocal collimator SPECT/CT within a 3-month period. A summed difference score (SDS) was calculated for each vascular territory from the MPI images. On CAG, a stenotic coronary artery was defined as one with luminal narrowing of ≥75 % with quantitative coronary angiography software. We analyzed the diagnostic accuracy of coronary artery stenosis detection using the definition that a coronary artery territory was ischemic when the SDS per vessel was ≥2. We generated receiver operating characteristic (ROC) curves to evaluate the usefulness of SDS per vascular territory to find coronary artery stenoses. The area under the ROC curve was 0.86 and cut-off value was 2. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy to detect stenoses were 85, 83, 66, 94 and 84 %, respectively. We confirmed the high accuracy of imaging with multifocal collimator SPECT/CT for detection of angiographically significant CAD.

  9. Microimaging studies of myocardial substrate utilization and perfusion in two models of non-coronary heart disease

    SciTech Connect

    Som, P.; Oster, Z.H.; Knapp, F.F. Jr.

    1987-01-01

    We have studied two animal models of non-coronary heart disease. The salt-sensitive Dahl strain hypertensive rats and their genetically matched normotensive controls and the cardiomyopathic BIO 53.58 (CM) strain Syrian hamsters with age and sex-matched RB strain controls. The CM strain hamster seems to be a very good model of human congestive cardiomyopathy and the Dahl strain hypertensive rats have also been found to be good models for studying the effects of hypertension on the myocardium. In our studies we compared the utilization of various metabolic substrates, viz., fatty acids, glucose analogs, and the early distribution of /sup 201/Tl, as an indicator of myocardial flow. The routine studies involving dissection of animals for assaying the radioactivity following the injection of radiopharmaceuticals is not suitable for assessing regional changes in metabolism and flow. The use of quantitative autoradiographic microimaging (ARG) enables the visualization of discrete regional as well as global changes from normal and to quantitate them. This paper describes the methodology and results of these investigations. 14 refs., 5 figs.

  10. Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

    PubMed Central

    McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Misselwitz, Bernd; Pilgram, Thomas; Gropler, Robert J.

    2010-01-01

    Objective To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. Methods A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99mTc-labeled red blood cells were injected to obtain respective gold standards. Results Microsphere-measured MBF and 99mTc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. Conclusions MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. PMID:20182731

  11. Physiological basis for angina and ST-segment change PET-verified thresholds of quantitative stress myocardial perfusion and coronary flow reserve.

    PubMed

    Johnson, Nils P; Gould, K Lance

    2011-09-01

    This study aimed to determine the quantitative low-flow threshold for stress-induced perfusion defects with severe angina and/or significant ST-segment depression during dipyridamole hyperemia. Vasodilator stress reveals differences in regional perfusion without ischemia in most patients. However, in patients with a perfusion defect, angina, and/or significant ST-segment depression during dipyridamole stress, quantitative absolute myocardial perfusion and coronary flow reserve (CFR) at the exact moment of definite ischemia have not been established. Defining these low-flow thresholds of angina or ST-segment changes may offer insight into physiological disease severity in patients with atherosclerosis. Patients underwent rest-dipyridamole stress positron emission tomography (PET) with absolute flow quantification in ml/min/g. Definite ischemia was defined as a new or worse perfusion defect during dipyridamole stress with significant ST-segment depression and/or severe angina requiring pharmacological treatment. Indeterminate clinical features required only 1 of these 3 abnormalities. The comparison group included patients without prior myocardial infarction, or angina or electrocardiographic changes after dipyridamole. In 1,674 sequential PET studies, we identified 194 (12%) with definite ischemia, 840 (50%) studies with no ischemia, and 301 (18%) that were clinically indeterminate. A vasodilator stress perfusion cutoff of 0.91 ml/min/g optimally separated definite from no ischemia with an area under the receiver-operator characteristic curve (AUC) of 0.98 and a CFR cutoff of 1.74 with an AUC = 0.91, reflecting excellent discrimination at the exact moment of definite ischemia. Thresholds of low myocardial vasodilator stress perfusion in ml/min/g and CFR sharply separate patients with angina or ST-segment change from those without these manifestations of ischemia during dipyridamole stress with excellent discrimination. Stress flow below 0.91 ml/min/g in dipyridamole

  12. Prognostic Value of Functional Variables as Assessed by Gated Thallium-201 Myocardial Perfusion Single Photon Emission Computed Tomography for Major Adverse Cardiac Events in Patients with Coronary Artery Disease.

    PubMed

    Shen, Thau-Yun; Chang, Ming-Che; Hung, Guang-Uei; Kao, Chia-Hung; Hsu, Bailing

    2013-05-01

    Gated single photon emission computed tomography (SPECT) using thallium-201 (Tl-201) has the capacity to evaluate the earlier post-stress (PS) function compared to technetium-99m labeled tracers, and may be more sensitive in detecting transient ventricular dysfunction caused by stress-induced ischemia. The purpose of this study was to assess the prognostic value of functional variables obtained from Tl-201 gated SPECT as a predictor of major adverse cardiac events (MACE). Four hundred and thirty-eight subjects who had known or suspected coronary artery disease and underwent clinically indicated dipyridamole-stress electrocardiography-gated Tl-201 SPECT were included in this study. Functional variables, including PS-ejection fraction (EF), PS-end systolic volume (ESV), PS-regional wall motion abnormality (RWA), reversible RWA and EF worsening, were generated to study the correlation with MACE (cardiac death, nonfatal infarction, unstable angina and coronary revascularization). Sixty-eight of the total 438 patients (15.5%) had MACE during the period of follow-up (a median time of 31 months), including 2 cardiac deaths, 9 non-fatal infarctions, 9 unstable angina and 48 coronary revascularizations. These events occurred significantly more frequently in patients with reversible RWA (28.8% vs. 7.1%, p < 0.0001), EF worsening (34.8% vs. 12.1%, p < 0.0001), PS-RWA (29.9% vs. 11.4%, p < 0.0001) and PS-EF < 45% (27.8% vs. 14.4%, p = 0.034). Using the Cox proportional hazards regression analysis, reversible RWA and EF worsening were two independent predictors of MACE, providing incremental prognostic value over clinical and perfusion-alone information. The functional assessment with Tl-201 gated SPECT was a useful prognosticator for patients who had known or suspected coronary artery disease. Coronary artery disease; Gated SPECT; Major adverse cardiac events; Tl-201.

  13. Myocardial perfusion and left ventricular function indices assessed by gated myocardial perfusion SPECT in methamphetamine abusers.

    PubMed

    Dadpour, Bita; Dabbagh Kakhki, Vahid R; Afshari, Reza; Dorri-Giv, Masoumeh; Mohajeri, Seyed A R; Ghahremani, Somayeh

    2016-12-01

    Methamphetamine (MA) is associated with alterations of cardiac structure and function, although it is less known. In this study, we assessed possible abnormality in myocardial perfusion and left ventricular function using gated myocardial perfusion SPECT. Fifteen patients with MA abuse, on the basis of Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) MA dependency determined by Structured Clinical Interview for DSM-IV, underwent 2-day dipyridamole stress/rest Tc-sestamibi gated myocardial perfusion SPECT. An average daily dose of MA use was 0.91±1.1 (0.2-4) g. The duration of MA use was 3.4±2.1 (1-7) years. In visual and semiquantitative analyses, all patients had normal gated myocardial perfusion SPECT, with no perfusion defects. In all gated SPECT images, there was no abnormality in left ventricular wall motion and thickening. All summed stress scores and summed rest scores were below 3. Calculated left ventricular functional indices including the end-diastolic volume, end-systolic volume, and left ventricular ejection fraction were normal. Many cardiac findings because of MA mentioned in previous reports are less likely because of significant epicardial coronary artery stenosis.

  14. Cost-effectiveness analysis of antiplatelet therapy in the prevention of recurrent stroke in the UK. Aspirin, dipyridamole and aspirin-dipyridamole.

    PubMed

    Chambers, M; Hutton, J; Gladman, J

    1999-11-01

    To evaluate the cost effectiveness from a UK health and social services perspective of antiplatelet therapies tested in the Second European Stroke Prevention Study (ESPS-2) in preventing recurrent stroke. To demonstrate the value of modelling studies in this area. A decision-analytic model was developed to evaluate health outcomes and associated costs. Sources of data for efficacy, adverse events, background event risks, disability and mortality were ESPS-2, the Oxfordshire Community Stroke Project and UK national statistics. Published national unit costs were applied to clinician panel estimates of resource use for acute stroke, rehabilitation and long term care. Outcome measures were strokes or disabled life-years averted, and disability-free, stroke-free or quality-adjusted life-years gained. 30-day survivors of ischaemic stroke treated with low dose aspirin, modified-release dipyridamole; the coformulation of low dose aspirin plus modified-release dipyridamole, or no antiplatelet therapy. The model predicted that over 5 years the coformulation prevented 29 more strokes than aspirin alone per 1000 patients, at an additional cost of 1900 Pounds per stroke averted (1996 values). Over 5 years, each antiplatelet therapy was cost saving compared with no therapy. Results were sensitive to the cost of acute care, the cost of long term care of disabled stroke survivors, the effectiveness of therapy and the background risk of recurrent stroke. In sensitivity analyses, the cost effectiveness did not exceed 7000 Pounds per stroke averted or 11,000 Pounds per quality-adjusted life-year (QALY) gained, except when varying the effectiveness parameter. Application of a decision-analytic model to the results of ESPS-2 indicated that first-line therapy with the coformulation of modified-release dipyridamole and low dose aspirin to patients with a previous ischaemic stroke is likely to generate significant health benefits at modest extra costs to health and social services. The

  15. Perfusion thallium imaging of type I diabetes patients with end stage renal disease: Comparison of oral and intravenous dipyridamole administration

    SciTech Connect

    Boudreau, R.J.; Strony, J.T.; duCret, R.P.; Kuni, C.C.; Wang, Y.; Wilson, R.F.; Schwartz, J.S.; Castaneda-Zuniga, W.R. )

    1990-04-01

    Eighty patients with type I diabetes and end stage renal disease were prospectively evaluated for coronary artery disease with dipyridamole-thallium-201 scintigraphy and quantitative coronary angiography. Forty patients received dipyridamole orally, and 40 received it intravenously. The prevalence of coronary artery disease was 53%. There were no significant differences in the accuracy of the two dipyridamole tests (sensitivity = 85%, specificity = 85%, accuracy = 85% for the oral group; sensitivity = 86%, specificity = 72%, accuracy = 79% for the intravenous group). Combining the 80 patients into a single group gave a sensitivity of 86%, a specificity of 79%, and an accuracy of 83% for the detection of coronary disease. Although the accuracy of this test in this patient population was similar to that previously reported for other groups, the prevalence of disease was high and resulted in a low predictive value of a negative test (83%).

  16. Detection of moderate regional ischemia in pig hearts in vivo by near-infrared and thermal imaging: effects of dipyridamole.

    PubMed

    Kupriyanov, Valery V; Manley, Darren M; Xiang, Bo

    2008-01-01

    Effects of coronary vasodilator, dipyridamole, on epicardial oxygenation and flow were investigated under conditions of moderate coronary occlusion using near-infrared spectroscopic (NIRS) and thermal imaging. In anesthetized open chest pigs an inflatable occluder and flow probe were placed around the left anterior descending artery (LAD). In the ischemic group (n = 11) LAD occlusion (50% flow, 80 min) was followed by complete occlusion (10 min, n = 4), and reflow. Dipyridamole was infused (0.14 mg/min/kg/4 min) intravenously during 50% occlusion. In the control group (n = 6) LAD flow was temporarily increased (hyperemic response) by two 2-min periods of complete LAD occlusion applied 120 min apart, with a 4-min period of dipyridamole infusion between the two occlusions. NIRS and thermal images were acquired throughout the protocol. Maps of subepicardial oxygen saturation parameter (OSP), and epicardial temperature (T) were obtained. Partial occlusion reduced OSP and the temperature by 0.23 +/- 0.08 and 0.88 +/- 0.39 degrees C versus remote region, respectively. Dipyridamole decreased systolic blood pressure by 36%, which caused further decline in the LAD flow to 18% and OSP and T by 0.37 +/- 0.01 and 2.46 +/- 0.32 degrees C, respectively. Reflow restored OSP and T to their baseline levels. In control group dipyridamole and hyperemia increased LAD flow 2-4-fold associated with moderate increase in OSP and T. OSP and T showed linear dependence on the flow below 100%, which is leveled-off at flows above normal. Dipyridamole increases differences in the epicardial oxygenation and T between normal and moderately ischemic areas due to enhancement of disparity in perfusion of these areas.

  17. Myocardial uptake and kinetic properties of technetium-99m-Q3 in dogs

    SciTech Connect

    Gerson, M.C.; Millard, R.W.; McGoron, A.J.

    1994-10-01

    We postulated that {sup 99m}Tc-Q3, a cationic imaging agent, produces myocardial activity related to myocardial blood flow during myocardial ischemia and pharmacologic coronary artery vasodilation, and shows little or no myocardial redistribution over 4 hr after intravenous injection. In six Group 1 dogs, the chest was opened, the left circumflex coronary artery was acutely ligated, and dipyridamole (0.32, 0.56 or 0.84 mg/kg) was infused into the right atrium, followed by 10 mCi of {sup 99m}Tc-Q3. Myocardial blood flow was measured by radiolabeled microspheres. The animals were euthanized and 357 myocardial samples were assayed in a well counter for {sup 99m}Tc activity. One week later, radiolabeled microsphere activity was counted and myocardial blood flow calculated. In nine Group 2 dogs, a variable occluder was placed around the left circumflex coronary artery and an ischemic level of circumflex blood flow was maintained constant over 4 hr as measured by an ultrasonic flow meter. Dipyridamole (0.56 mg/kg) was then infused into the right atrium followed by 10mCi of {sup 99m}Tc-Q3. Gamma camera images were acquired at 5, 15, 30, 60, 120 and 240 min following k{sup 99m}Tc-Q3 injection. Microsphere blood flow and endocardial biopsies (n - 6 dogs) were performed at 30, 60, 120 and 240 min following {sup 99m}TcQ3 injection. 31 refs., 9 figs., 1 tab.

  18. Use of oral dipyridamole SPECT thallium-201 imaging in detection of coronary artery disease

    SciTech Connect

    Beer, S.G.; Heo, J.; Kong, B.; Lyons, E.; Iskandrian, A.S. )

    1989-11-01

    This study examined the merits of oral dipyridamole SPECT thallium-201 imaging in detecting CAD and multivessel CAD. The 65 patients included in this study (aged 62 +/- 11 years) were not candidates for exercise testing (for the usual reasons). Coronary arteriography revealed no significant CAD in 17 patients and greater than or equal to 50% narrowing of one or more vessels in 48 patients; 12 had one-vessel and 36 had multivessel CAD (high-risk group). Thallium-201 was injected intravenously 45 minutes after an oral dose of 375 mg of dipyridamole, and SPECT imaging was performed within 10 minutes and 4 hours after injection. There were no serious side effects; only six patients (8%) had ST segment depression and 18 patients (28%) had chest pain. The heart rate increased from 74 +/- 15 beats/min at rest to 84 +/- 14 beats/min at peak effect (p = 0.001); the systolic blood pressure did not change (130 +/- 18 and 128 +/- 20 mm Hg, respectively, p = NS). The thallium images were abnormal in 6 of 17 patients (35%) with no CAD, in 7 of 12 patients with one-vessel disease (58%), and in 34 of 36 patients with multivessel CAD (94%) (p = 0.001). Twenty-one of 25 patients (84%) with a perfusion abnormality in more than one vascular territory had multivessel CAD assessed by angiography. Thus oral dipyridamole SPECT thallium-201 imaging is a safe and inexpensive method for the detection of CAD in patients who are otherwise not candidates for exercise testing.

  19. Economic assessment of the secondary prevention of ischaemic stroke with dipyridamole plus aspirin (Aggrenox/Asasantin) in France.

    PubMed

    Marissal, Jean-Pierre; Selke, Bernard

    2004-01-01

    To assess the cost effectiveness of aspirin 25 mg plus dipyridamole 200 mg twice daily in the secondary prevention of ischaemic stroke, according to the French social security perspective, using efficacy data from the second European Stroke Prevention Study (ESPS-2). The ESPS-2 was a double-blind, placebo-controlled clinical trial which assessed the efficacy of four secondary prevention strategies: (i) placebo; (ii) aspirin (acetylsalicylic acid) 25 mg twice daily; (iii) dipyridamole 200 mg twice daily; and (iv) aspirin 25 mg plus dipyridamole 200 mg twice daily. We performed a cost-effectiveness analysis with Monte Carlo simulations to compute confidence intervals. We combined data from various sources including the Dijon Stroke Registry, Institut National de la Statistique et des Etudes Economiques, Etude du Coût de l'Infarctus Cérébral (Study of the Cost of Cerebral Infarction [ECIC]) study and the ESPS-2 trial. According to our findings, a preventive strategy with aspirin 25 mg plus dipyridamole 200 mg twice daily is associated with net benefits per avoided stroke recurrence amounting to USD 23,932 (95% CI -USD 32,609, USD 35,772) compared with aspirin 25 mg twice daily alone, and USD 31,555 (95% CI USD 4921, USD 74,515) compared with dipyridamole alone (1997 values). Sensitivity analysis demonstrated that dipyridamole plus aspirin was still cost effective when the average cost of adverse effects per episode (ignored in the original estimation of the cost-effectiveness ratios due to a lack of data) was assumed to be USD 8600 (50,000 French francs); this cost is unlikely as most of the adverse effects associated with aspirin plus dipyridamole are only slight to moderate in severity. In the secondary prevention of stroke in France, this study suggests, given its underlying assumptions and data, that aspirin 25 mg plus dipyridamole 200 mg twice daily is likely to be a cost-effective strategy from the social security perspective, when compared with other

  20. Pronounced alterations in T-wave morphology during dipyridamole-induced ischaemia.

    PubMed

    Ferrando-Castagnetto, F; Ricca-Mallada, R; Ferrando-Castagnetto, R

    2016-01-01

    The case describes a 77-year-old woman with multivessel coronary disease exhibiting marked changes of T-wave morphology induced by dipyridamole, an unusual finding in which the diagnostic accuracy in this clinical context is uncertain. Gated-SPECT imaging demonstrated severe ischaemia extending through inferior and posterolateral regions of the left ventricle with normal motility and contractile function in response to vasodilator stress. Possible underlying mechanisms and clinical implications of observed electrocardiographic changes are discussed. T-loop modifications during vasodilator stress SPECT and correlation of these changes with the amount of ischaemic injury need further evaluation.

  1. Reverse screening approach to identify potential anti-cancer targets of dipyridamole

    PubMed Central

    Ge, Shu-Min; Zhan, Dong-Ling; Zhang, Shu-Hua; Song, Li-Qiang; Han, Wei-Wei

    2016-01-01

    Dipyridamole (DIP) inhibits thrombus formation when given chronically, and causes vasodilation over a short time. To date, DIP can increase the anticancer drugs (5-fluorouracil, methotrexate, piperidine, vincristine) concentration in cancer cells and hence enhance the efficacy of treatment cancer. The inhibition of DIP may result in increased 5-fluorouracil efficacy and diminish the drug side effects. But the actual molecular targets remain unknown. In this study, reverse protein-ligands docking, and quantum mechanics were used to search for the potential molecular targets of DIP. The quantum mechanics calculation was performed by using Gaussian 03 program package. Reverse pharmacophore mapping was used to search for potential molecular target candidates for a given small molecule. The docking study was used for exploring the potential anti-cancer targets of dipyridamole. The two predicted binders with the statistically significant prediction are dihydropyrimidine dehydrogenase (DPD) (PDB Id: 1GTE) and human spindle checkpoint kinase Bub1 (PDB Id: 3E7E). Structure analysis suggests that electrostatic interaction and hydrogen bonding play an important role in their binding process. The strong functional linkage of DIP and 5FU supports our prediction. In conclusion, these results generate a tractable set of anticancer proteins. The exploration of polypharmacology will provide us new opportunities in treating systematic diseases, such as the cancers. The results would generate a tractable set of anticancer target proteins for future experimental validations. PMID:28077994

  2. Sensitive and simple determination of the vasodilator agent dipyridamole in pharmaceutical preparations by phosphorimetry.

    PubMed

    Salinas-Castillo, A; Carretero, A Segura; Fernández-Gutiérrez, A

    2003-08-01

    The applicability of heavy atom-induced room-temperature phosphorescence to pharmaceutical samples is demonstrated in this work. Thus a new, simple, rapid, and selective phosphorimetric method for dipyridamole determination is proposed. The phosphorescence signals are a consequence of intermolecular protection when analytes are exclusively in the presence of heavy atom salts and sodium sulfite as an oxygen scavenger to minimize RTP quenching. The determination was performed in 0.1 mol L(-1) thallium(I) nitrate and 8 mmol L(-1) sodium sulfite at a measurement temperature of 20 degrees C. The phosphorescence intensity was measured at 635 nm, with excitation at 305 nm. Phosphorescence was easily developed; a linear concentration range was obtained between 0 and 100 ng mL(-1) with a detection limit of 940 ng L(-1), an analytical sensitivity of 2.5 ng mL(-1), and a standard deviation of 2.7% at 60 ng mL(-1) concentration. The method has been successfully applied to the analysis of dipyridamole in a unique Spanish commercial formulation containing 100 ng mL(-1) per capsule. The recovery was 101.6% with 6.5% standard deviation of analytical measurement. The method using the standard addition methodology has been validated.

  3. Vasodilator myocardial perfusion imaging: demonstration of local electrophysiological changes of ischaemia

    PubMed Central

    John, Roy M; Taggart, Peter I; Sutton, Peter M; Costa, Durval C; Ell, Peter J; Swanton, Howard

    1992-01-01

    Objective—To examine the incidence and severity of myocardial ischaemia provoked in the course of perfusion scintigraphy by coronary vasodilators using endocardial recordings of steady state monophasic action potentials as an independent marker of early localised myocardial ischaemia. Patients—31 men undergoing routine cardiac catheterisation for investigation of chest pain were studied. Setting—A tertiary cardiac referral centre. Design—Single site monophasic action potentials were recorded from the left or right ventricle or both (50 recording sites) during intravenous infusion of dipyridamole (0·015 mg/kg/min) for four minutes. Heart rate was held constant with atrial pacing at 20% above the patient's resting rate. Technetium-99m hexakis-2-methoxy-2-methylpropyl-isonitrile (MIBI) was administered four minutes after dipyridamole, and single photon emission tomographic imaging was performed an hour later. Rest images were obtained the next day (two day, two dose protocol). Recordings were divided into three groups based on the scintigraphic perfusion characteristics and coronary anatomical data for the action potential recording site: group 1—recordings from areas with a normal perfusion pattern (n = 30), group 2—recordings from areas with a perfusion defect and subtended by significantly narrowed coronary arteries without obvious angiographic collateral supply (n = 10), and group 3—recordings from areas with a perfusion defect and subtended by occluded arteries with angiographically evident collaterals from adjacent vessels (n = 10). Results—There were changes in the duration of the monophasic action potential indicative of ischaemia—that is, shortening of duration of steady state action potential—in 18 of the 20 recordings from areas of abnormal perfusion. Peak changes were apparent eight minutes from the start of the dipyridamole infusion. Mean (SEM) values for duration of the action potential between control and peak effect at eight

  4. Predictive value of quantitative dipyridamole-thallium scintigraphy in assessing cardiovascular risk after vascular surgery in diabetes mellitus

    SciTech Connect

    Lane, S.E.; Lewis, S.M.; Pippin, J.J.; Kosinski, E.J.; Campbell, D.; Nesto, R.W.; Hill, T. )

    1989-12-01

    Cardiac complications represent a major risk to patients undergoing vascular surgery. Diabetic patients may be particularly prone to such complications due to the high incidence of concomitant coronary artery disease, the severity of which may be clinically unrecognized. Attempts to stratify groups by clinical criteria have been useful but lack the predictive value of currently used noninvasive techniques such as dipyridamole-thallium scintigraphy. One hundred one diabetic patients were evaluated with dipyridamole-thallium scintigraphy before undergoing vascular surgery. The incidence of thallium abnormalities was high (80%) and did not correlate with clinical markers of coronary disease. Even in a subgroup of patients with no overt clinical evidence of underlying heart disease, thallium abnormalities were present in 59%. Cardiovascular complications, however, occurred in only 11% of all patients. Statistically significant prediction of risk was not achieved with simple assessment of thallium results as normal or abnormal. Quantification of total number of reversible defects, as well as assessment of ischemia in the distribution of the left anterior descending coronary artery was required for optimum predictive accuracy. The prevalence of dipyridamole-thallium abnormalities in a diabetic population is much higher than that reported in nondiabetic patients and cannot be predicted by usual clinical indicators of heart disease. In addition, cardiovascular risk of vascular surgery can be optimally assessed by quantitative analysis of dipyridamole-thallium scintigraphy and identification of high- and low-risk subgroups.

  5. Utilization of Gastrointestinal Simulator, an in Vivo Predictive Dissolution Methodology, Coupled with Computational Approach To Forecast Oral Absorption of Dipyridamole.

    PubMed

    Matsui, Kazuki; Tsume, Yasuhiro; Takeuchi, Susumu; Searls, Amanda; Amidon, Gordon L

    2017-03-03

    Weakly basic drugs exhibit a pH-dependent dissolution profile in the gastrointestinal (GI) tract, which makes it difficult to predict their oral absorption profile. The aim of this study was to investigate the utility of the gastrointestinal simulator (GIS), a novel in vivo predictive dissolution (iPD) methodology, in predicting the in vivo behavior of the weakly basic drug dipyridamole when coupled with in silico analysis. The GIS is a multicompartmental dissolution apparatus, which represents physiological gastric emptying in the fasted state. Kinetic parameters for drug dissolution and precipitation were optimized by fitting a curve to the dissolved drug amount-time profiles in the United States Pharmacopeia apparatus II and GIS. Optimized parameters were incorporated into mathematical equations to describe the mass transport kinetics of dipyridamole in the GI tract. By using this in silico model, intraluminal drug concentration-time profile was simulated. The predicted profile of dipyridamole in the duodenal compartment adequately captured observed data. In addition, the plasma concentration-time profile was also predicted using pharmacokinetic parameters following intravenous administration. On the basis of the comparison with observed data, the in silico approach coupled with the GIS successfully predicted in vivo pharmacokinetic profiles. Although further investigations are still required to generalize, these results indicated that incorporating GIS data into mathematical equations improves the predictability of in vivo behavior of weakly basic drugs like dipyridamole.

  6. Transient left ventricular cavitary dilation during dipyridamole-thallium imaging as an indicator of severe coronary artery disease

    SciTech Connect

    Lette, J.; Lapointe, J.; Waters, D.; Cerino, M.; Picard, M.; Gagnon, A. )

    1990-11-15

    Transient left ventricular (LV) cavitary dilation during dipyridamole-thallium imaging was reported in 45 of 510 (9%) consecutive patients referred for dipyridamole-thallium imaging. Clinical and hemodynamic effects observed during dipyridamole infusion were not predictive of transient cavitary dilation on the thallium images. Coronary angiography was performed in 32 of the 45 patients: 75% had either left main, 3-vessel or high-risk 2-vessel coronary artery disease. Although 25 of 45 patients (56%) with transient cavitary dilation were either asymptomatic or had only grade 1/4 effort angina, 16 of 25 patients (64%) not referred for coronary revascularization sustained a cardiac event during a mean follow-up of 12 months. Most events were cardiac deaths (75%) and 87% of events occurred within 4 months of the test. Noncardiac surgery was performed in 187 of the 510 patients. The postoperative cardiac event rate was 2% in the 101 patients with normal scans or fixed defects, 19% in 75 patients with reversible perfusion defects and 58% in 12 patients with reversible cavitary dilation (p less than 0.0001). Thus, transient LV dilation during dipyridamole-thallium imaging is a marker of severe underlying coronary artery disease, denotes a poor prognosis and predicts a high risk of postoperative cardiac complications in patients who undergo noncardiac surgery.

  7. Prevalence and clinical significance of residual myocardial ischemia 2 weeks after uncomplicated non-Q wave infarction: a prospective natural history study

    SciTech Connect

    Gibson, R.S.; Beller, G.A.; Gheorghiade, M.; Nygaard, T.W.; Watson, D.D.; Huey, B.L.; Sayre, S.L.; Kaiser, D.L.

    1986-06-01

    Despite having smaller infarct size and better left ventricular function, patients with non-Q wave myocardial infarction (NQMI) appear to have an unexpectedly high long-term mortality that is ultimately comparable to that of patients with Q-wave myocardial infarction (QMI). Patients with NQMI may lose their initial prognostic advantage because there is more viable tissue in the perfusion zone of the infarct-related vessel, rendering myocardium more prone to reinfarction. We tested this hypothesis in a prospective study of 241 consecutive patients 65 years of age or younger with acute uncomplicated myocardial infarction confirmed by creatine kinase levels (MB fraction). All patients received customary care and none underwent thrombolytic therapy or emergency angioplasty. Predischarge coronary angiography, radionuclide ventriculography, 24 hr Holter monitoring, and quantitative thallium-201 scintigraphy during treadmill exercise were performed 10 +/- 3 days after infarction. Infarcts were designated as QMI (n = 154) or NQMI (n = 87) by accepted criteria applied to serial electrocardiograms obtained on days 1, 2, 3, and 10. The baseline Norris coronary prognostic index, angiographic jeopardy scores, and prevalence of Lown grade ventricular arrhythmias were similar between groups despite evidence for less necrosis with NQMI vs QMI, reflected by lower peak creatine kinase levels (520 vs 1334 IU/liter; p = .0001, 4 hr sampling), higher resting left ventricular ejection fraction (53% vs 46%; p = .0001), fewer akinetic or dyskinetic segments (1.2 vs 2.4; p = .0001), and fewer persistent /sup 201/Tl defects in the infarct zone. Patients with NQMI also had more patent infarct-related vessels and a shorter time from onset of infarction to peak creatine kinase level.

  8. Effect of caffeine on myocardial perfusion imaging using single photon emission computed tomography during adenosine pharmacologic stress.

    PubMed

    Kovacs, Daniela; Pivonka, Robert; Khosla, Pam G; Khosla, Sandeep

    2008-01-01

    Approximately 6 million cardiac stress tests are performed annually in the United States, of which 2.4 million are pharmacologic stress tests using agents such as adenosine. Adenosine induces differential coronary hyperemia in normal coronary arteries versus coronary arteries with atherosclerosis, allowing single photon emission computed tomography (SPECT) imaging to identify reduced coronary flow in segments subtended by diseased coronary arteries. The potential attenuation of pharmacologic effects of adenosine in the presence of caffeine is why patients are routinely instructed to abstain from caffeine for 12 to 24 hours prior to administration of an adenosine stress test. Failure to abstain from caffeine results in cancellation or delaying of cardiac stress testing, resulting in procedural delays and its impact on patient throughput. Recent studies have evaluated such interaction and suggested a lack of clinically significant effect of caffeine on adenosine-induced hyperemia during myocardial SPECT imaging. This article reviews the clinical pharmacology of caffeine, adenosine, and dipyridamole and effect of caffeine on myocardial stress testing using adenosine and dipyridamole in clinical cardiovascular medicine. The limited published data are conflicting, but some recent publications suggest that myocardial perfusion SPECT imaging using adenosine may not be clinically significantly altered by routine consumption of caffeine, such as a cup of coffee. Although prospective randomized studies would be required to obtain a definitive answer to this question, it appears on the basis of some of the studies reviewed in this article that caffeine consumption prior to myocardial perfusion imaging may not necessitate cancellation or rescheduling of adenosine stress testing.

  9. Myocardial viability.

    PubMed Central

    Birnbaum, Y; Kloner, R A

    1996-01-01

    Left ventricular function is a major predictor of outcome in patients with coronary artery disease. Acute ischemia, postischemic dysfunction (stunning), myocardial hibernation, or a combination of these 3 are among the reversible forms of myocardial dysfunction. In myocardial stunning, dysfunction occurs despite normal myocardial perfusion, and function recovers spontaneously over time. In acute ischemia and hibernation, there is regional hypoperfusion. Function improves only after revascularization. Evidence of myocardial viability usually relies on the demonstration of uptake of various metabolic tracers, such as thallium (thallous chloride TI 201) or fludeoxyglucose F 18, by dysfunctional myocardium or by the demonstration of contractile reserve in a dysfunctional region. This can be shown as an augmentation of function during the infusion of various sympathomimetic agents. The response of ventricular segments to increasing doses of dobutamine may indicate the underlying mechanism of dysfunction. Stunned segments that have normal perfusion show dose-dependent augmentation of function. If perfusion is reduced as in hibernating myocardium, however, a biphasic response usually occurs: function improves at low doses of dobutamine, whereas higher doses may induce ischemia and, hence, dysfunction. But in patients with severely impaired perfusion, even low doses may cause ischemia. Myocardial regions with subendocardial infarction or diffuse scarring may also have augmented contractility during catecholamine infusion due to stimulation of the subepicardial layers. In these cases, augmentation of function after revascularization is not expected. Because the underlying mechanism, prognosis, and therapy may differ among these conditions, it is crucial to differentiate among dysfunctional myocardial segments that are nonviable and have no potential to regain function, hibernating or ischemic segments in which recovery of function occurs only after revascularization, and

  10. Effect of surfactants, gastric emptying, and dosage form on supersaturation of dipyridamole in an in vitro model simulating the stomach and duodenum.

    PubMed

    Mitra, A; Fadda, H M

    2014-08-04

    The purpose of this study was to investigate the influence of gastric emptying patterns, surfactants, and dosage form on the supersaturation of a poorly soluble weakly basic drug, dipyridamole, using an in vitro model mimicking the dynamic environment of the upper gastrointestinal tract, and, furthermore, to evaluate the usefulness of this model in establishing correlations to in vivo bioavailability for drugs with solubility/dissolution limited absorption. A simulated stomach duodenum model comprising four compartments was used to assess supersaturation and precipitation kinetics as a function of time. It integrates physiologically relevant fluid volumes, fluid transfer rates, and pH changes of the upper GI tract. Monoexponential gastric emptying patterns simulating the fasted state were compared to linear gastric emptying patterns simulating the fed state. The effect of different surfactants commonly used in oral preparations, specifically, sodium lauryl sulfate (SLS), poloxamer-188, and polysorbate-80, on dipyridamole supersaturation was investigated while maintaining surface tension of the simulated gastric fluids at physiological levels and without obtaining artificial micellar solubilization of the drug. The supersaturation behavior of different dose strengths of dipyridamole was explored. Significant levels of dipyridamole supersaturation were observed in the duodenal compartment under all the different in vivo relevant conditions explored. Dipyridamole supersaturation ratios of up to 11-fold have been observed, and supersaturation has been maintained for up to 120 min. Lower duodenal concentrations of dipyridamole were observed under linear gastric emptying patterns compared to mononexponential gastric emptying. The mean duodenal area under concentration-time curves (AUC60min) for the dipyridamole concentration profile in the duodenal compartment is significantly different for all the surfactants explored (P < 0.05). Our investigations with the different

  11. In Vitro Dissolution of Fluconazole and Dipyridamole in Gastrointestinal Simulator (GIS), Predicting in Vivo Dissolution and Drug-Drug Interaction Caused by Acid-Reducing Agents.

    PubMed

    Matsui, Kazuki; Tsume, Yasuhiro; Amidon, Gregory E; Amidon, Gordon L

    2015-07-06

    Weakly basic drugs typically exhibit pH-dependent solubility in the physiological pH range, displaying supersaturation or precipitation along the gastrointestinal tract. Additionally, their oral bioavailabilities may be affected by coadministration of acid-reducing agents that elevate gastric pH. The purpose of this study was to assess the feasibility of a multicompartmental in vitro dissolution apparatus, Gastrointestinal Simulator (GIS), in predicting in vivo dissolution of certain oral medications. In vitro dissolution studies of fluconazole, a BCS class I, and dipyridamole, a BCS class II weak bases (class IIb), were performed in the GIS as well as United States Pharmacopeia (USP) apparatus II and compared with the results of clinical drug-drug interaction (DDI) studies. In both USP apparatus II and GIS, fluconazole completely dissolved within 60 min regardless of pH, reflecting no DDI between fluconazole and acid-reducing agents in a clinical study. On the other hand, seven-fold and 15-fold higher concentrations of dipyridamole than saturation solubility were observed in the intestinal compartments in GIS with gastric pH 2.0. Precipitation of dipyridamole was also observed in the GIS, and the percentage of dipyridamole in solution was 45.2 ± 7.0%. In GIS with gastric pH 6.0, mimicking the coadministration of acid-reducing agents, the concentration of dipyridamole was equal to its saturation solubility, and the percentage of drug in solution was 9.3 ± 2.7%. These results are consistent with the clinical DDI study of dipyridamole with famotidine, which significantly reduced the Cmax and area under the curve. An In situ mouse infusion study combined with GIS revealed that high concentration of dipyridamole in the GIS enhanced oral drug absorption, which confirmed the supersaturation of dipyridamole. In conclusion, GIS was shown to be a useful apparatus to predict in vivo dissolution for BCS class IIb drugs.

  12. Non-invasive prediction of angiographic progression of coronary artery disease by dipyridamole-stress echocardiography.

    PubMed

    Rodriguez, O; Picano, E; Fedele, S; Morelos, M; Marzilli, M; Ungi, I

    2001-05-01

    Coronary angiography is the currently accepted standard means for assessing progression of coronary artery disease. A dipyridamole-echocardiography test (DET) might provide an alternative non-invasive functional imaging method for this purpose. To assess whether variations in results of serial DET match variations in angiographic assessments of coronary artery disease. From the Pisa Institute of Clinical Physiology stress-echocardiography data bank (1983-1998), we selected 60 patients satisfying the inclusion criteria of coronary angiography and DET having each been performed and interpreted twice independently and within 1 week. The second angiographic and stress-echocardiographic assessment was performed 45+/-31 months after the initial one. Angiographic progressors were defined a priori as patients with any progression of stenosis to occlusion and those with any stenosis > 30% with > 20% progression of stenosis measured by visual and quantitative coronary angiography. Stress-echocardiography progressors were defined as those patients who had previously had a negative test of a test having a positive result and those patients who had positive results of tests both in initial testing and in a second session of testing with the latter having a peak wall-motion-score index > 0.12 (on a scale of 1, normal to 4, dyskinetic in a 16-segment model) larger than the former. Of the 60 patients, 44 were angiographic 'progressors' and 16 were 'non progressors'. Stress-echocardiographic responses were concordant with angiographic identification for 39 of 44 progressors and 15 of 16 non-progressors, with an overall concordance of 90%. Measurement of dipyridamole-stress-echocardiographic response allows one to separate angiographic progressors and non-progressors efficiently, simply by taking into account the presence, extent and severity of stress-induced abnormalities of wall motion.

  13. Prognostic utility of intravenous dipyridamole thallium-201 imaging and exercise testing after an acute infarction

    SciTech Connect

    Leppo, J.A.

    1984-01-01

    To define the prognosis in asymptomatic survivors of acute infarcts (MI), coronary vasodilation was induced with I.V. dipyridamole, followed by Thallium-201 (T1) imaging in 26 patients just prior to discharge. All patients (pts) also had a modified exercise treadmill (MET) test. During the imaging protocol, 10 (39%) pts experienced transient adverse effects and 12 (46%) pts had either angina or ST depression with MET. During a mean follow-up of 17 months, 13 (50%) pts had a cardiac event defined as readmission for control of angina, MI or death. In the 13 pts having cardiac events, 4 (31%) had ST depression and 2 (15%) had angina during MET, but 12 (92%) demonstrated T1 redistribution (RD) as determined by at least 1 segment/scan having a transient defect. A logistic regression analysis using several exercise, scintigraphic and general clinical parameters, showed that the presence of T1 RD was the only significant (p <0.001) predictor for future cardiac events. The predicted probability for events in pts with T1 RD was 80 +- 10% (SD) and was 9 +- 9% in those without T1 RD. The mean number of defects per scan was similar in pts with and without cardiac events, but compared to persistent defects, transient ones are associated with potentially ischemic myocardium. Although the pt population is relatively small, dipyridamole T1 imaging after MI appears to be safe and has demonstrated prognostic value. It also offers an alternative and/or addition to exercise testing in the predischarge evaluation after acute MI.

  14. Pharmacological and other nonexercise alternatives to exercise testing to evaluate myocardial perfusion and left ventricular function with radionuclides

    SciTech Connect

    DePuey, E.G.; Rozanski, A. )

    1991-04-01

    Pharmacological vasodilatation with either dipyridamole or adenosine is a safe and accurate alternative to exercise testing to diagnose coronary artery disease with thallium 201 myocardial perfusion imaging. The technique also provides important prognostic information with regard to future cardiac events in patients undergoing diagnostic testing, in those evaluated preoperatively, and in those with recent myocardial infarctions. Multigated equilibrium and first-pass radionuclide ventriculography also are well suited to evaluate the effects of interventional procedures. Success has been achieved using this methodology in a variety of interventions including conventional exercise testing, pharmacological stress testing, atrial pacing, assessment of myocardial viability with nitroglycerin, mental stress testing, and ambulatory monitoring of left ventricular ejection fraction. 67 references.

  15. Alterations in myocardial metabolism and function at rest in stable angina pectoris: relations with the amount of exercise-induced thallium-201 perfusion defect

    SciTech Connect

    De Kock, M.; Melin, J.A.; Pouleur, H.; Rousseau, M.F.

    1986-01-01

    The relation between the amount of exercise-induced ischemia and alterations in left ventricular (LV) function and metabolism at rest was studied in 18 coronary patients with stable angina pectoris. An ischemic defect area score was computed from quantitative exercise thallium-201 (Tl-201) scintigraphy; this estimation of the amount of ischemic myocardium was used to classify the patients in group I (n = 8; score less than 15%, mean 6.7 +/- 2.5%) and II (n = 10; score greater than 15%; mean 27.2 +/- 8.9%). Hemodynamics and metabolism were studied in basal state. No patient had anginal pain during the study, and the extent of angiographic coronary artery disease (CAD) was comparable in the two groups. Heart rate, aortic pressure, coronary blood flow, and myocardial oxygen uptake were also similar in both groups. However, ejection fraction was reduced in group II (51 +/- 13 vs 63 +/- 5%; p less than 0.01) and LV relaxation was impaired as shown by the increase in time-constant of isovolumic pressure fall (55 +/- 16 vs 44 +/- 6 ms in group I; p less than 0.05); the LV end-diastolic pressure was also increased in group II (19 +/- 8 vs 10 +/- 4 mmHg in group l; p less than 0.05). Furthermore, in group II, myocardial lactate uptake was reduced (4 +/- 19 vs 30 +/- 29 mumole/min in group I; p less than 0.01) and the productions of alanine and glutamine were augmented (-7.5 +/- 4.4 vs -4.6 +/- 1.6 mumole/min in group I; p less than 0.05).

  16. Platelet involvement in the nephritis of acute serum sickness in rabbits: protection by dipyridamole and FUT-175.

    PubMed Central

    Koyama, A; Inage, H; Sano, M; Narita, M; Tojo, S; Neild, G H; Cameron, J S

    1985-01-01

    In the acute serum sickness model in rabbits, we investigated platelet release of 5-HT, platelet surface immunoglobulins, and platelet aggregation in response to ADP, together with the effect of dipyridamole and the Clr antagonist FUT-175. The immune release of 5-HT from platelets occurred between 4 and 6 days after injection of bovine serum albumin (BSA), before immune elimination and proteinuria, but coincident with the appearance of immune complexed BSA in the circulation. Nevertheless, platelet turnovers were not detectably accelerated. Treatment with dipyridamole 50 mg/kg/24 h prevented the release of 5-HT and inhibited proteinuria, glomerular hypercellularity and immune complexes in the glomeruli. Using the Clr antagonist FUT-175, similar abrogation of the disease was obtained. We conclude that in the nephritis of acute serum sickness in rabbits, some of the immune release from platelets may be the result of immune complex binding to the platelet, perhaps through the receptor for C3b. PMID:4042428

  17. Noninvasive stress testing of myocardial perfusion defects: head-to-head comparison of thallium-201 SPECT to MRI perfusion.

    PubMed

    Vincenti, Gabriella; Nkoulou, René; Steiner, Charles; Imperiano, Hestia; Ambrosio, Giuseppe; Mach, François; Ratib, Osman; Vallee, Jean-Paul; Schindler, Thomas H

    2009-01-01

    To evaluate the diagnostic value of magnetic resonance imaging (MRI) of myocardial perfusion in the assessment of flow-limiting epicardial stenosis in a head-to-head comparison with abnormal thallium-201 ((201)TI) single photon emission tomography (SPECT) studies in patients with predominantly known coronary artery disease (CAD). Twenty-one patients (mean age 65 +/- 10 years) with reversible myocardial perfusion defects on (201)TI-SPECT images during dipyridamole-stimulated hyperemia were recruited for study purpose. Within 5 days of the (201)TI-SPECT study, myocardial perfusion was studied again with MRI during dipyridamole stimulation and at rest. Overall, (201)TI-SPECT identified 30 reversible regional perfusion defects. The sensitivity to detect hypoperfused segments was 70% (21/30) with the GRE-MRI perfusion analysis with (201)TI-SPECT as reference. When patients were subgrouped according to the extent of regional reversible perfusion defects on (201)TI-SPECT, mild- (SDS: 2-4), moderate- (SDS: 5-8), and severe- (SDS > 8) perfusion defects were also identified by GRE-MRI perfusion analysis in 75% (6/8), in 56% (9/16) and 100% (6/6), respectively. GRE-MRI first-pass stress perfusion imaging may not identify up to 30% of mild-to-moderate perfusion defects in a group of preselected patients with predominantly known CAD and abnormal (201)TI-SPECT studies.

  18. Abnormal myocardial perfusion and risk of heart failure in patients with type 2 diabetes mellitus

    PubMed Central

    Utrera-Lagunas, Marcelo; Orea-Tejeda, Arturo; Castillo-Martínez, Lilia; Balderas-Muñoz, Karla; Keirns-Davis, Candace; Espinoza-Rosas, Sarahi; Sánchez-Ortíz, Néstor Alonso; Olvera-Mayorga, Gabriela

    2013-01-01

    BACKGROUND: Diabetes is a major risk factor for heart failure (HF), although the pathophysiological processes have not been clarified. OBJECTIVE: To determine the prevalence of HF and of abnormal myocardial perfusion in diabetic patients evaluated using technetium (99m) sestamibi single-photon emission computed tomography. METHODS: An observational cross-sectional study was conducted that included patients with type 2 diabetes mellitus who underwent echocardiography to diagnose HF and a pharmacological stress test with intravenous dipyridamole to examine cardiac scintigraphic perfusion abnormalities. Clinical and biochemical data were also collected. RESULTS: Of the 160 diabetic patients included, 92 (57.6%) were in HF and 68 (42.5%) were not. When patients were stratified according to the presence of abnormal myocardial perfusion, those with abnormal perfusion had a higher prevalence of HF (93%) than those with normal perfusion (44.4%) (P<0.0001). Patients with HF weighed more (P=0.03), used insulin less frequently (P=0.01), had lower total cholesterol (P=0.05) and high-density lipoprotein cholesterol concentrations (P=0.002), and a greater number of their myocardial segments showed abnormal perfusion (P≤0.001). More HF patients had a history of myocardial infarction (P<0.001) compared with those without HF. In a logistic regression analysis, the number of segments exhibiting abnormal myocardial perfusion was an independent risk factor for HF. CONCLUSIONS: The prevalence of HF in diabetic patients was high and HF predominantly occured in association with myocardial ischemia. PMID:24294048

  19. [Influence of dipyridamole on expression of PAC-1 and CD62p in patients with malignant lymphoma].

    PubMed

    Jiang, Ya-Jun; Li, Xiu-Mei; Wang, Hong-Xia; Kang, Li-Li; Zhu, Gui-Hua; Zhuang, Wan-Chuan

    2010-08-01

    This study was purposed to explore the expressions of platelet-activated markers PAC-1 and CD62p in peripheral blood of malignant lymphoma patients and the influence of dipyridamole on their expression. 32 lymphoma patients were divided into simple chemotherapy group (simple group) and chemotherapy plus dipyridamole group (combined group) randomly, and 15 healthy peoples were selected as control group. The dipyridamole of 100 mg/day was given to the patients in combined group. The expression levels of PAC-1, CD62p and fibrinogen (Fib) were detected by flow cytometry and magnetic bead method on day 0, 3, 7 and 14 of chemotherapy respectively. The results showed that the levels of PAC-1, CD62p and Fib in lymphoma patients were significantly higher than those in control group (p < 0.01, 0.05), moreover there was positive correlation between levels of PAC-1 and Fib (r = 0.549, p < 0.01). PAC-1 expression on day 0 and 3 of chemotherapy in simple group was higher than that on day 14 (p < 0.05, 0.01) and CD62p expression on day 3 of chemotherapy was higher than that on day 0, 7 and 14 (p < 0.05, 0.01). PAC-1 expression in combined group on day 14 of chemotherapy was lower than than on day 0 and 3 (p < 0.05, 0.01), and CD62p on day 14 was lower than that on day 3 of chemotherapy (p < 0.05); PAC-1 and CD62p expressions in combined group on day 3, 7 and 14 of chemotherapy were decreased than those in simple group, but Fib level was not changed significantly. It is concluded that the patients with malignant lymphoma usually accompany with platelet activation and hyperfibrinogenemia in peripheral blood. Applying dipyridamole routine dosage in chemotherapy can efficiently restrain platelet activation.

  20. Left-ventricular dyssynchrony evaluated by Tl-201 gated SPECT myocardial perfusion imaging: a comparison with Tc-99m sestamibi.

    PubMed

    Chen, Chien-Cheng; Huang, Wen-Sheng; Hung, Guang-Uei; Chen, Wan-Chen; Kao, Chia-Hung; Chen, Ji

    2013-03-01

    Phase analysis of gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has been validated as a reliable tool to assess left-ventricular (LV) mechanical dyssynchrony. The initial results were all confirmed from studies using technetium-99m (Tc-99m) sestamibi or tetrofosmin as the radiotracers. The purpose of this study was to evaluate the feasibility of phase analysis in thallium-201 (Tl-201) gated SPECT MPI. Seventeen patients referred from a cardiology clinic for evaluation of coronary artery disease were studied. All patients underwent both Tl-201 and Tc-99m sestamibi gated SPECT MPI within 1 week. An additional 34 patients with Tl-201 gated SPECT and 22 patients with Tc-99m sestamibi gated SPECT, who had a low likelihood of coronary artery disease, normal LV function, and normal perfusion on MPI, were used as normal controls. LV dyssynchrony parameters, including phase standard deviation (PSD) and phase histogram bandwidth (PHB), were measured using a standard phase analysis tool and compared between Tl-201 and Tc-99m sestamibi images. The LV dyssynchrony parameters correlated well (r=0.93 for PSD and r=0.84 for PHB) between Tl-201 and Tc-99m sestamibi images. The dyssynchrony parameters of Tl-201 were significantly larger than those of Tc-99m sestamibi (PSD: 24.5±12.0 vs. 17.4±9.7, P<0.001; PHB: 74.7±35.5 vs. 50.6±25.0, P<0.001). In comparison with normal controls, Tl-201 and Tc-99m sestamibi images showed concordant results. LV dyssynchrony parameters correlated well between Tl-201 and Tc-99m sestamibi images, even though the values were significantly larger for Tl-201 than for Tc-99m sestamibi. Tl-201 images showed results similar to those of Tc-99m sestamibi in the diagnosis of LV dyssynchrony.

  1. Evaluation in dogs of a new double-dose technique for imaging changes in myocardial perfusion

    SciTech Connect

    Rothendler, J.A.; Okada, R.D.; Strauss, H.W.; Chesler, D.A.; Pohost, G.M.

    1984-06-01

    Assessment of myocardial perfusion with thallium immediately before and after an intervention that alters blood flow has been difficult due to presence of residual activity from the first tracer dose at the time of the second imaging. In a canine model the authors investigated a technique using two separate thallium injections during an intervention and after its reversal. Images were obtained after each injection, and a difference image was obtained by subtracting the first from the second image to correct for tracer persisting from the first injection. Interventions on coronary blood flow included: transient occlusion, subcritical stenosis with dipyridamole infusion, and permanent occlusion. The first images showed defects corresponding to the occlusion or stenosis, while the ''difference'' images correlated with myocardial perfusion at the time of the second injection.

  2. Myocardial uptake and clearance of T1-201 in healthy subjects: Comparison of adenosine-induced hyperemia and exercise stress

    SciTech Connect

    Siffring, P.A.; Gupta, N.C.; Mohiuddin, S.M.; Esterbrooks, D.J.; Hilleman, D.E.; Cheng, S.C.; Sketch, M.H. Sr.; Frick, M.P. )

    1989-12-01

    Pharmacologic stress testing with dipyridamole is useful in patients undergoing thallium-201 myocardial perfusion scintigraphy who cannot adequately exercise. Because dipyridamole increases coronary blood flow by reducing the metabolism of adenosine, the authors compared the uptake and clearance of T1-201 following exercise stress testing (EST) and resting intravenous infusion of adenosine (AI) in crossover fashion in 20 healthy men. No perfusion defects or areas of redistribution were noted in any of the scans. Mean absolute myocardial T1-201 uptake was 1.3 times greater with AI than with EST. Mean absolute extracardiac uptake was 2.0 times greater with AI. Mean T1-201 myocardial clearance was virtually the same in all AI and EST views. During AI, 70% of the subjects experienced subjective side effects, mean arterial blood pressure decreased by 15%, and heart rate increased by 48%. The effects of adenosine on T1-201 kinetics in the myocardium are similar to those of EST. Adenosine may be useful as a pharmacologic stress agent in patients undergoing T1-201 myocardial perfusion scintigraphy.

  3. Nuclear cardiology: Myocardial perfusion and function

    SciTech Connect

    Seldin, D.W. )

    1991-08-01

    Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references.

  4. Variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects.

    PubMed

    Kofoed, Klaus F; Hove, Jens D; Freiberg, Jacob; Høst, Ulla; Holm, Søren; Kelbaek, Henning

    2002-12-01

    The aim of this study was to assess regional and global variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects and to evaluate potentially responsible factors. Twenty men with a mean age of 64 years, no history of cardiovascular disease, and normal blood pressure, bicycle exercise test, electrocardiogram and echocardiography were studied [ P(coronary artery disease) <5%]. Whole-body insulin sensitivity and insulin-stimulated myocardial glucose uptake were measured during hyperinsulinaemic euglycaemic glucose clamp with fluorine-18 fluorodeoxyglucose, and myocardial rest and hyperaemic blood flow during dipyridamole infusion were measured with nitrogen-13 ammonia and positron emission tomography in 16 left ventricular myocardial segments. Intra-individual and inter-individual variability of insulin-stimulated myocardial glucose uptake [relative dispersion = (standard deviation/mean)] was 13% and 29% respectively. Although inter-individual variability of glucose uptake and blood flow at rest was of the same magnitude, no correlation was found between these measures. Regional and global insulin-stimulated myocardial glucose uptake correlated linearly with whole-body insulin sensitivity ( r=0.51, P<0.05 and r=0.56, P<0.01). The strongest independent association by multivariate linear regression analysis was found between myocardial glucose uptake and hyperaemic blood flow ( r=0.63, P<0.005). We conclude that in healthy elderly subjects, insulin-stimulated myocardial glucose uptake is homogeneous throughout the left ventricle, but has moderate inter-individual variability. Inter-individual variability of insulin-stimulated myocardial glucose uptake is primarily explained by variability in coronary vascular reactivity and tissue insulin sensitivity.

  5. The effect of a slower than standard dose escalation scheme for dipyridamole on headaches in secondary prevention therapy of strokes: a randomized, open-label trial (DOSE).

    PubMed

    de Vos-Koppelaar, N C Martine; Kerkhoff, Henk; de Vogel, Ed M; Zock, Elles; Dieleman, Hetty G

    2014-01-01

    Combination therapy with acetylsalicylic acid and dipyridamole is first-line treatment in secondary prevention of strokes. Approximately 40% of patients report headache as a side effect of dipyridamole. Dose escalation of dipyridamole reduces this side effect. In practice, different dose escalation schemes are used. In theory, slower dose escalation than a standard scheme reduces headaches even more. This study aimed to find the best dose escalation scheme for prevention of headaches as a side effect of dipyridamole in the secondary prevention of strokes. In this randomized, open-label, 4-week trial, 114 patients who had an ischemic stroke or transient ischemic attack were randomized to receive either a standard or slow dose escalation scheme of dipyridamole. Participants were asked to report the four most common side effects of dipyridamole in a study diary on study days 1, 3, 5, 7, 14, 21 and 28. They were asked to score headache intensity on a visual analog scale (VAS). Participants were unaware that the trial was focused on headaches. Primary end point was to determine if a slow dose escalation scheme reduces the percentage of patients with headaches. Secondary objective was to determine the number of patients who discontinued treatment with dipyridamole because of headaches. Overall 37 patients (38%) of the final population reported headache, 19 (39%) in the standard dose escalation group and 18 (37%) in the slow dose escalation group (p = 1.0). In the standard dose escalation group patients scored headaches (VAS >4) on an average of 3.3 days and patients in the slow dose escalation group on 3.6 days (p = 0.82). Mean VAS scores on study days 1, 3, 5, 7, 14 and 21 ranged from 1.4 to 3.7 in both groups. These scores did not differ significantly. However, on day 28 patients scored a significantly lower mean VAS score in the standard dose escalation group than in the slow dose escalation group (2.5 vs. 4.8; p = 0.05). In the standard dose escalation group 6

  6. Additive effects of statin and dipyridamole on cerebral blood flow and stroke protection

    PubMed Central

    Kim, Hyung-Hwan; Sawada, Naoki; Soydan, Guray; Lee, Ho-Seong; Zhou, Zhipeng; Hwang, Seo-Kyoung; Waeber, Christian; Moskowitz, Michael A; Liao, James K

    2008-01-01

    Recent studies suggest that dipyridamole (DP) may exert stroke protective effects beyond platelet inhibition. The purpose of this study is to determine whether statin and DP could enhance stroke protection through nitric oxide (NO)-dependent vascular effects. Mice were pretreated with DP (10 to 60 mg/kg, q 12 h, 3 days) alone or in combination with a statin (simvastatin; 0.1 to 20 mg/kg per day, 14 days) before transient intraluminal middle cerebral artery occlusion. Although simvastatin (1 mg/kg per day, 14 days) increased endothelial NO synthase (eNOS) activity by 25% and DP (30 mg/kg, q12 h, 3 days) increased aortic cGMP levels by 55%, neither statin nor DP alone, at these subtherapeutic doses, increased absolute cerebral blood flow (CBF) or conferred stroke protection. However, the combination of subtherapeutic doses of simvastatin and DP increased CBF by 50%, decreased stroke volume by 54%, and improved neurologic motor deficits, all of which were absent in eNOS-deficient mice. In contrast, treatment with aspirin (10 mg/kg per day, 3 days) did not augment the neuroprotective effects of DP and/or simvastatin. These findings indicate that statin and DP exert additive NO-dependent vascular effects and suggest that the combination of statin and DP has greater benefits in stroke protection than statin alone through vascular protection. PMID:18382469

  7. Validation of a short-scan-time imaging protocol for thallium-201 myocardial SPECT with a multifocal collimator.

    PubMed

    Horiguchi, Yoriko; Ueda, Tomohiro; Shiomori, Tomofumi; Kanna, Masahiko; Matsushita, Hirooki; Kawaminami, Tomoko; Sudo, Yuta; Kikuchi, Shinnosuke; Sasaki, Ryo; Hoshimiya, Jun; Morita, Yukiko

    2014-10-01

    IQ-SPECT (Siemens AG, Munich, Germany) is a highly sensitive single-photon-emission computed tomography (SPECT) myocardial perfusion imaging (MPI) system that uses a multifocal collimator. We searched for a suitable protocol for short-time imaging by IQ-SPECT in thallium-201 (Tl-201) MPI by evaluating phantom images and also by comparing human IQ-SPECT images with conventional SPECT images as reference standards. We assessed the image quality using the normalized mean square error (NMSE) and drew up count profiles in Tl-201 SPECT images acquired with IQ-SPECT in a phantom study. We also performed Tl-201 stress myocardial SPECT/CT in 21 patients and compared delayed images acquired by using IQ-SPECT with 36 or 17 views per head with images obtained by using conventional SPECT. The NMSE of SPECT images from IQ-SPECT with 36 views was approximately one-fifth of that with 17 views. The myocardial count profile of images with 17 views was lower than those of images with 36 or 104 views in some regions. Defect scores were significantly lower, and image quality scores higher, in images from conventional SPECT than in those from IQ-SPECT with 17 views. Defect scores and image quality scores were equivalent in images from conventional SPECT and those from IQ-SPECT with 36 views. Agreement with the results of conventional SPECT in terms of coronary artery territory-based defect judgment was the best in IQ-SPECT with 36 views with computed tomography-derived attenuation correction (CTAC): the kappa values for IQ-SPECT with 36 views were 0.76 (without CTAC) and 0.83 (with CTAC), and those for IQ-SPECT with 17 views were 0.62 (without CTAC) and 0.59 (with CTAC). The difference in quantitative tracer uptake between conventional SPECT images and IQ-SPECT images was significantly greater for IQ-SPECT images with 17 views than for those with 36 views. Scanning with 36 views per head with CTAC may be appropriate for Tl-201 MPI using IQ-SPECT, because it provides images equivalent to

  8. Determinants of the response of left ventricular ejection fraction to vasodilator stress in electrocardiographically gated (82)rubidium myocardial perfusion PET.

    PubMed

    Brown, Tracy L Y; Merrill, Jennifer; Volokh, Lana; Bengel, Frank M

    2008-02-01

    Myocardial perfusion imaging with (82)Rb PET allows for ECG-gated studies to be obtained early after radiotracer injection, capturing ventricular function close to peak pharmacologic action of dipyridamole. This is different from gated SPECT and may potentially provide additional diagnostic information. We sought to identify potential correlates of the PET-derived ejection fraction response to vasodilator stress. One hundred ten consecutive patients undergoing (82)Rb PET myocardial perfusion imaging during evaluation for coronary artery disease were included. Using a GE Discovery STRx PET-CT scanner, ECG-gated images (eight bins) were obtained at rest and 4 min after dipyridamole infusion, 90 s after infusion of 1,480-2,220 MBq of (82)Rb. Summed rest, stress, and difference scores (SRS, SSS, and SDS) were determined using a five-point scoring system and 20-segment model. Ejection fraction was calculated using automated QGS software. Significant reversibility (SDS > or = 4) was found in 23 patients (21%). Mean LVEF in all patients was 47 +/- 13% at rest and 53 +/- 13% during dipyridamole. LVEF increased in 89 patients, and decreased in 17 patients during vasodilation. The change in LVEF was inversely correlated with SDS (r = -0.26; p = 0.007). Additionally, it was inversely correlated with resting LVEF (r = -0.20; p = 0.03) and SSS (r = -0.25; p = 0.009). No significant correlations were observed with SRS, heart rate, blood pressure, age, hypertension, hypercholesterolemia, or pretest likelihood of disease. At multivariate regression analysis, SDS was an independent predictor of the change in LVEF. Gated (82)Rb PET during pharmacologic stress allows for assessment of the functional response to vasodilation. The magnitude of LVEF increase is determined by stress perfusion/reversible perfusion defects. Functional response to hyperemia may thus be incorporated in future evaluations of diagnostic and prognostic algorithms based on (82)Rb PET.

  9. Blood oxygen level-dependent (BOLD) MRI: A novel technique for the assessment of myocardial ischemia as identified by nuclear imaging SPECT.

    PubMed

    Egred, M; Waiter, G D; Redpath, T W; Semple, S K I; Al-Mohammad, A; Walton, S

    2007-12-01

    The different levels of deoxyhemoglobin in the ischemic myocardium, induced by stressors such as dipyridamole, can be detected by blood oxygen level-dependent (BOLD) MRI and may be used to diagnose myocardial ischemia. The aim of this study was to assess the signal change in the myocardium on BOLD MRI as well as wall thickening between rest and dipyridamole stress images in ischemic and non-ischemic myocardium as identified on SPECT imaging. Twelve patients with stress-induced myocardial ischemia on SPECT underwent rest and dipyridamole stress MRI using a double breath-hold, T2()-weighted, ECG-gated sequence to produce BOLD contrast images as well as cine-MRI for wall thickening assessment in 10 of the 12 patients. Signal change on BOLD MRI and wall thickening were compared between rest and stress images in ischemic and non-ischemic myocardial segments as identified on SPECT. In each patient, two MRI slices containing 16 segments per slice were analysed. In total, there were 384 segments for BOLD analysis and 320 for wall thickening. For BOLD signal 137 segments correlated to segments with reversible ischemia on SPECT and 247 to normal segments, while for wall thickening 112 segments correlated to segments with reversible ischemia and 208 to normal segments. The average BOLD MRI signal intensity change was -13.8 (+/-16.3)% in the ischemic segments compared to -10.3 (+/-14.7)% in the non-ischemic segments (p=0.05). The average wall thickening was 6.4 (+/-3.4) mm in the ischemic segments compared to 8.7 (+/-3.8) mm in the non-ischemic segments (p<0.0001). Stress-induced ischemic myocardium has a different signal change and wall thickening than non-ischemic myocardium and may be differentiated on BOLD MRI. Larger studies are needed to define a threshold for detection and to determine the sensitivity and specificity of this technique.

  10. Myocardial perfusion scintigraphy and coronary disease risk factors in systemic lupus erythematosus

    PubMed Central

    Sella, E; Sato, E; Leite, W; Filho, J; Barbieri, A

    2003-01-01

    Objective: To evaluate the prevalence of myocardial perfusion abnormalities and the possible association between myocardial perfusion defects and traditional coronary artery disease (CAD) risk factors as well as systemic lupus erythematosus (SLE) related risk factors. Patients and methods: Female patients with SLE, disease duration >5 years, age 18–55 years, who had used steroids for at least one year were enrolled. Traditional CAD risk factors evaluated were arterial hypertension, diabetes mellitus, dyslipidaemia, postmenopausal status, smoking, obesity, and premature family CAD profile. Myocardial perfusion scintigraphy was evaluated by single photon emission computed tomography with technetium 99m-sestamibi at rest and after dipyridamole induced stress. Results: Eight two female patients with SLE without angina pectoris with mean (SD) age 37 (10) years, disease duration 127 (57) months, SLE Disease Activity Index (SLEDAI) score 6 (5), and SLICC/ACR-DI score 2 (2) were evaluated. Myocardial perfusion abnormalities were found in 23 patients (28%). The mean (SD) number of CAD risk factors was 2.2 (1.6). There was a significant positive correlation between age and number of CAD risk factors. Lower high density lipoprotein (HDL) cholesterol level showed a significant association with abnormal scintigraphy. Logistic regression analysis showed that lower HDL cholesterol level and diabetes mellitus were associated with myocardial perfusion abnormalities. Current vasculitis was also associated with abnormal scintigraphy. Conclusions: Lower HDL cholesterol level and diabetes mellitus have a significant influence on abnormal myocardial perfusion results found in asymptomatic patients with SLE. Current vasculitis was associated with abnormal myocardial scintigraphy. These data suggest that abnormal myocardial scintigraphy may be related to subclinical atherosclerosis. PMID:14583569

  11. Fixed defect on rest/stress Tc-99m sestamibi study underestimates myocardial ischemia: comparison with 24-hour thallium-201 study for short- and intermediate-term follow-up.

    PubMed

    Kong, Grace; Lichtenstein, Meir; Gunawardana, Dishan; Better, Nathan; Roysri, Krisana; Sivaratnam, Dinesh

    2008-03-01

    We assessed whether a same day rest/stress gated Tc-99m sestamibi (MIBI) SPECT myocardial study underestimates reversible ischemia in patients with fixed perfusion defects compared with a 24-hour thallium-201 (Tl-201) study. The short- and intermediate-term outcome with or without Tl-201 reversibility was assessed. Forty-nine consecutive patients with fixed MIBI defects received an additional Tl-201 study and were evaluated. Tl-201 was given to patients with a high clinical suspicion of underestimation of reversibility. Images were interpreted semiquantitatively by 3 nuclear medicine physicians using a 17-segment, 5-point model. A summed stress score (SSS) from stress MIBI images, a summed rest score (SRS) from Tl images, and a summed difference (SDS = SSS - SRS) score were calculated. SDS >3 indicated significant Tl-201 redistribution. Composite end points included acute myocardial infarction, unstable angina needing admission, cardiac death, or revascularization within 3 and 6 months. Fifteen of 49 patients showed no Tl-201 redistribution. Thirty-four of 49 (69%) patients had significant Tl-201 redistribution, and these patients had significantly higher cardiac events (CE) at 3 months (29% vs. 7%; P = 0.039), and higher at 6 months (32% vs. 7%; P = 0.027). These patients with CE had a larger amount of Tl-201 redistribution, mean SDS 8.6 vs. 5.3 (P = 0.047). Patients with significant Tl-201 redistribution had a lower left ventricular ejection fraction (mean 37%; P = 0.001). With short- and intermediate-term follow-up, our study shows a significant association towards fixed defects on the rest/stress MIBI study underestimating CE risk when compared with a delayed Tl-201 study, especially in patients with a large amount of Tl-201 redistribution. Hence, the addition of a Tl-201 study may be useful in the management of patients with large fixed MIBI defects, especially with a depressed left ventricular ejection fraction.

  12. Application of Three-Class ROC Analysis to Task-Based Image Quality Assessment of Simultaneous Dual-Isotope Myocardial Perfusion SPECT (MPS)

    PubMed Central

    He, Xin; Song, Xiyun; Frey, Eric C.

    2009-01-01

    The diagnosis of cardiac disease using dual-isotope myocardial perfusion SPECT (MPS) is based on the defect status in both stress and rest images, and can be modeled as a three-class task of classifying patients as having no, reversible, or fixed perfusion defects. Simultaneous acquisition protocols for dual-isotope MPS imaging have gained much interest due to their advantages including perfect registration of the 201Tl and 99mTc images in space and time, increased patient comfort, and higher clinical throughput. As a result of simultaneous acquisition, however, crosstalk contamination, where photons emitted by one isotope contribute to the image of the other isotope, degrades image quality. Minimizing the crosstalk is important in obtaining the best possible image quality. One way to minimize the crosstalk is to optimize the injected activity of the two isotopes by considering the three-class nature of the diagnostic problem. To effectively do so, we have previously developed a three-class receiver operating characteristic (ROC) analysis methodology that extends and unifies the decision theoretic, linear discriminant analysis, and psychophysical foundations of binary ROC analysis in a three-class paradigm. In this work, we applied the proposed three-class ROC methodology to the assessment of the image quality of simultaneous dual-isotope MPS imaging techniques and the determination of the optimal injected activity combination. In addition to this application, the rapid development of diagnostic imaging techniques has produced an increasing number of clinical diagnostic tasks that involve not only disease detection, but also disease characterization and are thus multiclass tasks. This paper provides a practical example of the application of the proposed three-class ROC analysis methodology to medical problems. PMID:18955172

  13. Three-class ROC analysis: a sequential decision model developed for the diagnostic task rest-stress myocardial perfusion SPECT imaging

    NASA Astrophysics Data System (ADS)

    He, Xin; Frey, Eric C.

    2008-03-01

    Previously we have developed a decision model for three-class ROC analysis where classification is made three simultaneously, i.e., with a single decision. In this paper, an alternative sequential decision model was developed for the specific three-class diagnostic procedure of rest-stress myocardial perfusion SPECT (MPS) imaging. This sequential decision model was developed based on the fact that sometimes this diagnostic task is performed using a two-step process. First, the stress ( 99m Tc) image is read to determine whether a patient is normal or abnormal based on the presence of a defect in the stress image. If a defect is found, the rest ( 201Tl) image is then read to determine whether this is a reversible defect or a fixed defect based on the presence of defect on the rest image. In fact, in some MPS protocols where sequential stress/rest imaging is performed, the rest imaging is not performed if there is no defect in the stress image. Therefore, the three-class task is decomposed to a sequence of two two-class tasks. For this task we determined, by maximizing the expected utility of both steps of the decision process, that log likelihood ratios were the optimal decision variables and provide the optimal ROC surface under the assumption that incorrect decisions have equal utilities under the same hypothesis. The properties of the sequential decision model were then studied. We found that the sequential decision model shares most of the features of a 2-class ROC curve. While this model was developed in the context of rest-stress MPS, it may have applications to other two-step diagnostic tasks.

  14. Limited myocardial perfusion reserve in patients with left ventricular hypertrophy

    SciTech Connect

    Goldstein, R.A.; Haynie, M. )

    1990-03-01

    Experimental studies in animals have suggested that coronary flow reserve may be limited in patients with left ventricular hypertrophy (LVH). Accordingly, to noninvasively determine the effect of LVH on myocardial perfusion reserve, 25 patients, 9 with LVH and 16 controls, underwent positron imaging with rubidium-82 (82Rb) (30-55 mCi) or nitrogen-13 (13N) ammonia (12-19 mCi) at rest and following intravenous dipyridamole and handgrip stress. LVH was documented by echocardiographic and/or electrocardiographic measurements. LVH patients had either no chest pain (n = 8) and/or a normal coronary angiogram (n = 6). Nine simultaneous transaxial images were acquired, and the mean ratio of stress to rest activity (S:R), based on all regions for each heart, was calculated as an estimate of myocardial perfusion reserve. There were no regional differences in activity (i.e., perfusion defects) in any of the studies. S:R averaged 1.41 +/- 0.10 (s.d.) for controls and 1.06 +/- 0.09 for patients with LVH (p less than 0.0001). These data provide support for an abnormality in perfusion reserve in patients with LVH.

  15. Dipyridamole perfusion scintigraphy: The experience with its application in one hundred seventy patients with known or suspected unstable angina

    SciTech Connect

    Zhu, Y.Y.; Chung, W.S.; Botvinick, E.H.; Dae, M.W.; Lim, A.D.; Ports, T.A.; Danforth, J.W.; Wolfe, C.L.; Goldschlager, N.; Chatterjee, K. )

    1991-01-01

    We evaluated the safety, accuracy, and potential clinical utility of intravenous dipyridamole perfusion scintigraphy with thallium-201 in 170 patients, 78 with suspected and 92 with known unstable angina. All had coronary angiography. Noncardiac side effects (26%), induced chest discomfort (44%), and ST segment changes (12%) were similar in the two groups. No significant arrhythmias occurred. Two patients had prolonged chest pain, both with extensive reversible image abnormalities and associated creatinine kinase-MB release. Both had elective bypass surgery. Twenty-eight patients had normal coronary arteries, and 35 had single-vessel disease. Scintigraphic per patient sensitivity and specificity were 91% and 79% with a per vessel sensitivity of 74% and a per vessel specificity of 78% without between-group differences. During a brief follow-up period, 62 patients with image abnormalities had coronary revascularization, and there were seven deaths without intergroup differences. In a similar patient group that did not have angiography, scintigraphic defects were less frequent and less extensive, revascularization was not performed, and subsequent deaths occurred less often. Dipyridamole perfusion scintigraphy is an accurate alternative to exercise testing in the evaluation of patients with unstable angina pectoris. Although not without risk, the method appears relatively safe and should be considered as a guide to diagnosis, and probably to prognosis and management.

  16. Applying preoperative dipyridamole thallium-201 scintigraphy for preventing cardiac mortality and complications for patients with secondary hyperparathyroidism undergoing parathyroidectomy.

    PubMed

    Yin, Shih-Min; Chou, Fong-Fu; Wu, Shao-Chun; Chi, Shun-Yu

    2017-07-06

    To evaluate the value of preoperative dipyridamole thallium-201 scintigraphy for reducing cardiovascular complication in secondary hyperparathyroidism (SHPTH) patients. Thallium scintigraphy was arranged for all dialysis patients who underwent parathyroidectomy from Jan 2011 to July 2015. Management of defects on thallium scintigraphy included cardiac catheterization and ultrasonography. Analysis includes 30-day mortality, morbidity and the predicting factors for thallium scintigraphy defect. Of 249 patients with SHPTH, 19 (7.6%) had defects on thallium scintigraphy, 15 (88%) of whom had coronary artery disease on angiography. History of acute coronary syndrome (ACS, p < 0.001), diabetes mellitus (DM, p = 0.03), male sex (p = 0.03), and higher body mass index (BMI, p = 0.001) were significant predictors of positive thallium scintigraphy results. History of ACS was the most significant predictor after adjustment in the multivariate logistic analysis (odds ratio, 22.56; 95% confidence interval, 7.02-72.53). All the patients survived the 30-day postoperative period, with minimal cardiovascular morbidity. Preoperative dipyridamole thallium-201 scintigraphy is useful for SHPTH patients to minimized surgical mortality and morbidity. Copyright © 2017. Published by Elsevier Taiwan.

  17. Myocardial blood flow quantification for evaluation of coronary artery disease by computed tomography

    PubMed Central

    Seitun, Sara; Clemente, Alberto; La Grutta, Ludovico; Toia, Patrizia; Runza, Giuseppe; Midiri, Massimo; Maffei, Erica

    2017-01-01

    During the last decade coronary computed tomography angiography (CTA) has become the preeminent non-invasive imaging modality to detect coronary artery disease (CAD) with high accuracy. However, CTA has a limited value in assessing the hemodynamic significance of a given stenosis due to a modest specificity and positive predictive value. In recent years, different CT techniques for detecting myocardial ischemia have emerged, such as CT-derived fractional flow reserve (FFR-CT), transluminal attenuation gradient (TAG), and myocardial CT perfusion (CTP) imaging. Myocardial CTP imaging can be performed with a single static scan during first pass of the contrast agent, with monoenergetic or dual-energy acquisition, or as a dynamic, time-resolved scan during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson). A number of CTP techniques are available, which can assess myocardial perfusion in both a qualitative, semi-quantitative or quantitative manner. Once used primarily as research tools, these modalities are increasingly being used in routine clinical practice. All these techniques offer the substantial advantage of combining anatomical and functional evaluation of flow-limiting coronary stenosis in the same examination that would be beneficial for clinical decision-making. This review focuses on the state-of the-art and future trends of these evolving imaging modalities in the field of cardiology for the physiologic assessments of CAD. PMID:28540209

  18. Kinetics and dosimetry of thallium-201 in human testes

    SciTech Connect

    Rao, D.V.; Shepstone, B.J.; Wilkins, H.B. ||

    1995-04-01

    Thallous chloride ({sup 201}Tl) is a well-known imaging agent. It has been shown to accumulate in the testes. In view of this, the testicular kinetics of {sup 201}Tl is investigated in humans and the absorbed dose to the organ calculated. Thallous chloride {sup 201}Tl was injected intravenously into four patients for myocardial perfusion studies. After clinical evaluation, the testicular uptake and clearance of {sup 201}Tl were monitored for about 1 wk using a gamma camera. Testicular uptake of {sup 201}Tl was rapid with a mean biological uptake half-time of 0.67 hr and mean biological clearance half-time of 280 hr. The mean maximum testicular uptake of {sup 201}Tl was about 0.4% of the injected activity. These data were utilized to calculate the average absorbed dose to the testes. The absorbed dose to the testes was calculated to be 3.5 x 10{sup {minus}4} Gy/MBq (1.3 rad/mCi) of injected activity. When the relative biological effectiveness of the Auger emitter {sup 201}Tl is taken into account, the equivalent dose to the testes is 9.5 x 10{sup {minus}4} Sv/MBq (3.5 rem/mCi). 14 refs., 1 fig., 2 tabs.

  19. SIMULTANEOUS DUAL-RADIONUCLIDE MYOCARDIAL PERFUSION IMAGING WITH A SOLID-STATE DEDICATED CARDIAC CAMERA

    PubMed Central

    Ben-Haim, S.; Kacperski, K.; Hain, S.; Van Gramberg, D.; Hutton, B.F.; Waddington, W.A.; Sharir, T.; Roth, N.; Berman, D.S.; Ell, P.J.

    2011-01-01

    We compared simultaneous dual-radionuclide stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. Methods 24 consecutive patients (64.5 ± 11.8 years, 16 men) were injected with 74 MBq of 201Tl (rest) and 250 MBq 99mTc-MIBI (stress). Conventional MPI acquisition times for stress and rest were 21 min and 16 min, respectively. A simultaneous dual-radionuclide (DR) 15 minute list mode gated acquisition was performed on D-SPECT (Spectrum-dynamics, Caesarea, Israel). The DR D-SPECT data were processed using a spillover and scatter correction method. We compared DR D-SPECT images with conventional SPECT images by visual analysis employing the 17-segment model and a 5-point scale (0=normal, 4=absent) to calculate the summed stress and rest scores (SSS and SRS, respectively) and the % visual perfusion defect (TPD) at stress and rest, by dividing the stress and rest scores, respectively, by 68 and multiplying by 100. TPD <5% was considered normal. Image quality was assessed on a 4-point scale (1=poor, 4=very good) and gut activity was assessed on a 4-point scale (0=none, 3=high). Results Conventional MPI was abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI was abnormal in 113 vs. 93 abnormal segments by conventional MPI. In the nine abnormal rest studies DR D-SPECT was abnormal in 45 vs. 48 segments abnormal by conventional MPI. SSS, SRS, TPD stress and TPD rest on conventional SPECT and DR D-SPECT highly correlated (r=0.9790, 0.9694, 0.9784, 0.9710, respectively; p<0.0001 for all). In addition, 6 patients had significantly larger perfusion defects on DR D-SPECT stress images, including five of 11 patients who were imaged earlier on D-SPECT than conventional SPECT. Conclusion D-SPECT enables fast and high quality simultaneous DR MPI in a single imaging session with comparable diagnostic performance and

  20. In vivo quantitation of platelet deposition on human peripheral arterial bypass grafts using indium-111-labeled platelets. Effect of dipyridamole and aspirin

    SciTech Connect

    Pumphrey, C.W.; Chesebro, J.H.; Dewanjee, M.K.; Wahner, H.W.; Hollier, L.H.; Pairolero, P.C.; Fuster, V.

    1983-03-01

    Indium-111-labeled autologous platelets, injected 48 hours after operation, were used to evaluate the thrombogenicity of prosthetic material and the effect of platelet inhibitor therapy in vivo. Dacron double-velour (Microvel) aortofemoral artery bifurcation grafts were placed in 16 patients and unilateral polytetrafluoroethylene femoropopliteal grafts were placed in 10 patients. Half the patients in each group received platelet inhibitors before operation (dipyridamole, 100 mg 4 times a day) and after operation (dipyridamole, 75 mg, and acetylsalicylic acid, 325 mg 3 times a day); the rest of the patients served as control subjects. Five-minute scintigrams of the graft region were taken with a gamma camera interfaced with a computer 48, 72, and 96 hours after injection of the labeled platelets. Platelet deposition was estimated from the radioactivities of the grafts and expressed as counts per 100 pixels per microcurie injected. Dipyridamole and aspirin therapy significantly reduced the number of platelets deposited on Dacron grafts and prevented platelet accumulation over 3 days. With the small amount of platelet deposition on polytetrafluoroethylene femoropopliteal artery grafts even in control patients, platelet inhibitor therapy had no demonstrable effect on platelet deposition on these grafts. It is concluded that (1) platelet deposition on vascular grafts in vivo can be quantitated by noninvasive methods, and (2) dipyridamole and aspirin therapy reduced platelet deposition on Dacron aortofemoral artery grafts.

  1. New approach for quantitative analysis of myocardial perfusion with magnetic resonance first-pass bolus imaging

    NASA Astrophysics Data System (ADS)

    Oswald, Helmut; Schnackenburg, Bernd; Bornstedt, Axel; Gross, Michael; Al-Saadi, Nidal; Nagel, Eicke; Fleck, Eckart

    1999-05-01

    Myocardial perfusion reserve can be noninvasively assessed with cardiovascular magnetic resonance. With magnetic resonance (MR) multislice dynamic imaging techniques it is possible to acquire the complete heart during the first pass of a contrast agent bolus. For diagnostic reasons an important question is to obtain quantitative parameters of the perfusion of the myocardium. We developed a model for the analysis of the contrast agent bolus pass in the myocardium and established a process for the complete task, which will support a routine clinical use delivering these quantitative parameters in a reproducible way. To evaluate the analysis in a collective of patients with single vessel disease and without significant coronary artery disease the signal intensity curves of the first pass of a gadolinium-DTPA bolus injected via a central vein were estimated before and after dipyridamole infusion.

  2. Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

    PubMed

    Seitun, Sara; Castiglione Morelli, Margherita; Budaj, Irilda; Boccalini, Sara; Galletto Pregliasco, Athena; Valbusa, Alberto; Cademartiri, Filippo; Ferro, Carlo

    2016-02-01

    Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed.

  3. Myocardial Perfusion SPECT 2015 in Germany

    PubMed Central

    Burchert, Wolfgang; Schäfer, Wolfgang; Hacker, Marcus

    2016-01-01

    Summary Aim The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. Method 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. Results MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1% [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. Conclusion The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring. PMID:27909712

  4. The usefulness of stress tests performed in the nuclear medicine department: mathematical methods to assess efficacy at various angiographic endpoints.

    PubMed

    Hurwitz, G A; Weingert, M E; Silver, D L; MacDonald, A C; Finnie, K J; Powe, J E; Dawdy, J A

    1996-06-01

    Stress myocardial perfusion scintigraphy (SMPS) may be used to amplify or supplant information available from stress electrocardiography (ECG) in directing the clinical management of patients, including the need for coronary angiography. The apparent usefulness of SMPS may depend on referral bias, the stress mode employed and the criterion for disease. We compared markers of ischaemia on quantitative planar SMPS with 201 Tl in 503 referred patients; stress was tailored to the individual patient to include exercise (n = 154), dipyridamole (n = 118) or a combination of the two (n = 231). Four angiographic criteria of increasing severity (A-D) were targeted. The fraction of the population receiving diagnostic benefit was calculated for reversible defects (RD) or lung uptake (LU) in comparison to concurrent ST depression; abnormal baseline tracings and fixed 201Tl defects were regarded as indeterminate. Decision tree induction, a computer-learning algorithm and logistic regression were also used to assess the contribution of 13 scintigraphic and other input variables. In comparison to ST depression, RD showed incremental value in 167 (33%) patients with criterion A, decreasing to 5% with criterion D; LU showed its greatest benefit (21%) with criterion D. Both scintigraphic markers were more useful with dipyrida-mole-based tests than with exercise alone. Decision trees induced at each criterion for disease showed the predominant contribution of scintigraphic results in comparison to clinical and ECG data. In conclusion, in a referred population with a frequent requirement for pharmacological stress, the clinical utility of scintigraphy can be determined by comparison of markers of ischaemia; the results will depend, however on the angiographic criterion for disease.

  5. Necrobiosis lipoidica: a case with histopathological findings revealed asteroid bodies and was successfully treated with dipyridamole plus intralesional triamcinolone.

    PubMed

    Jiquan, Song; Khalaf, Ahmad T; Jinquan, Tan; Xiaoming, Liu

    2008-01-01

    The significance of necrobiosis lipoidica (NL) includes its relationship with insulin-dependent diabetes mellitus, its tendency to break down into painful ulcers, an albeit tenuous association with squamous cell carcinoma and, by no means least, its cosmetic impact, occurring as it does on the shins of young and middle-aged women. Necrobiosis (degeneration of collagen) and granulomous inflammation are well-documented histological findings in NL; however, to see an asteroid body in an area of NL is rare. To the best of our knowledge, there is only one such report of NL described so far. We report the case of a NL patient whose histopathological examination revealed asteroid bodies. The patient had suffered persistent NL for a period of more than 2 years. She was successfully treated with dipyridamole plus intralesional triamcinolone and the lesions healed completely after 2 months of therapy. The patient has remained free of lesions since discontinuing therapy.

  6. The neuron-astrocyte-microglia triad in a rat model of chronic cerebral hypoperfusion: protective effect of dipyridamole

    PubMed Central

    Lana, Daniele; Melani, Alessia; Pugliese, Anna Maria; Cipriani, Sara; Nosi, Daniele; Pedata, Felicita; Giovannini, Maria Grazia

    2014-01-01

    Chronic cerebral hypoperfusion during aging may cause progressive neurodegeneration as ischemic conditions persist. Proper functioning of the interplay between neurons and glia is fundamental for the functional organization of the brain. The aim of our research was to study the pathophysiological mechanisms, and particularly the derangement of the interplay between neurons and astrocytes-microglia with the formation of “triads,” in a model of chronic cerebral hypoperfusion induced by the two-vessel occlusion (2VO) in adult Wistar rats (n = 15). The protective effect of dipyridamole given during the early phases after 2VO (4 mg/kg/day i.v., the first 7 days after 2VO) was verified (n = 15). Sham-operated rats (n = 15) were used as controls. Immunofluorescent triple staining of neurons (NeuN), astrocytes (GFAP), and microglia (IBA1) was performed 90 days after 2VO. We found significantly higher amount of “ectopic” neurons, neuronal debris and apoptotic neurons in CA1 Str. Radiatum and Str. Pyramidale of 2VO rats. In CA1 Str. Radiatum of 2VO rats the amount of astrocytes (cells/mm2) did not increase. In some instances several astrocytes surrounded ectopic neurons and formed a “micro scar” around them. Astrocyte branches could infiltrate the cell body of ectopic neurons, and, together with activated microglia cells formed the “triads.” In the triad, significantly more numerous in CA1 Str. Radiatum of 2VO than in sham rats, astrocytes and microglia cooperated in the phagocytosis of ectopic neurons. These events might be common mechanisms underlying many neurodegenerative processes. The frequency to which they appear might depend upon, or might be the cause of, the burden and severity of neurodegeneration. Dypiridamole significantly reverted all the above described events. The protective effect of chronic administration of dipyridamole might be a consequence of its vasodilatory, antioxidant and anti-inflammatory role during the early phases after 2VO

  7. Myocardial imaging. Coxsackie myocarditis

    SciTech Connect

    Wells, R.G.; Ruskin, J.A.; Sty, J.R.

    1986-09-01

    A 3-week-old male neonate with heart failure associated with Coxsackie virus infection was imaged with Tc-99m PYP and TI-201. The abnormal imaging pattern suggested myocardial infarction. Autopsy findings indicated that the cause was myocardial necrosis secondary to an acute inflammatory process. Causes of abnormal myocardial uptake of Tc-99m PYP in pediatrics include infarction, myocarditis, cardiomyopathy, bacterial endocarditis, and trauma. Myocardial imaging cannot provide a specific cause diagnosis. Causes of myocardial infarction in pediatrics are listed in Table 1.

  8. Clopidogrel and modified-release dipyridamole for the prevention of occlusive vascular events (review of Technology Appraisal No. 90): a systematic review and economic analysis.

    PubMed

    Greenhalgh, J; Bagust, A; Boland, A; Martin Saborido, C; Oyee, J; Blundell, M; Dundar, Y; Dickson, R; Proudlove, C; Fisher, M

    2011-09-01

    Occlusive vascular events such as myocardial infarction (MI), ischaemic stroke and transient ischaemic attack (TIA) are the result of a reduction in blood flow associated with an artery becoming narrow or blocked through atherosclerosis and atherothrombosis. Peripheral arterial disease is the result of narrowing of the arteries that supply blood to the muscles and other tissues, usually in the lower extremities. The primary objective in the treatment of all patients with a history of occlusive vascular events and peripheral arterial disease is to prevent the occurrence of new occlusive vascular events. To assess the clinical effectiveness and cost-effectiveness of clopidogrel and modified-release dipyridamole (MRD) alone or with aspirin (ASA) compared with ASA (and each other where appropriate) in the prevention of occlusive vascular events in patients with a history of MI, ischaemic stroke/TIA or established peripheral arterial disease. To consider the clinical effectiveness and cost-effectiveness of clopidogrel in patients with multivascular disease. This review is an update of the evidence base for the National Institute for Health and Clinical Excellence (NICE) guidance Technology Appraisal No. 90 (TA90) entitled Clopidogrel and modified-release dipyridamole for the prevention of occlusive vascular events (2005). Four electronic databases (EMBASE, MEDLINE, Web of Science and The Cochrane Library) were searched for randomised controlled trials (RCTs) and economic evaluations. Submissions to NICE by the manufacturers of the interventions were also considered. A systematic review of clinical effectiveness and cost-effectiveness was conducted. To manage heterogeneity between trials, indirect analysis (using a mixed-treatment methodology) was performed on selected clinical outcomes. A new economic model was developed to assess incremental costs per life-year gained [quality-adjusted life-years (QALYs)]. For evidence of clinical effectiveness, four RCTs were

  9. Coronary flow reserve assessed by myocardial contrast echocardiography predicts mortality in patients with heart failure.

    PubMed

    Anantharam, Brijesh; Janardhanan, Raj; Hayat, Sajad; Hickman, Michael; Chahal, Navtej; Bassett, Paul; Senior, Roxy

    2011-01-01

    the aim of the study was to assess whether myocardial contrast echocardiography (MCE) can predict mortality in patients with heart failure. Myocardial viability, ischaemia, and coronary flow reserve (CFR) are predictors of mortality in patients with heart failure. MCE can assess myocardial viability, ischaemia, and CFR at the bedside. However, its prognostic value is unknown in patients with heart failure. eighty-seven patients (age: 68 ± 10 years, 62% male) with heart failure [left ventricular ejection fraction (LVEF): 35% ± 13] underwent low-power intermittent MCE at rest and 2 min after dipyridamole infusion. Resting and stress perfusion score index were derived qualitatively. CFR (MBF at stress/MBF at rest) was calculated by a quantitative method. All patients underwent coronary arteriography. Patients were followed up for mortality. Of the 87 patients, 43 (49%) patients had coronary artery disease. There were 28 (32%) deaths during a mean follow-up of 4.1 ± 1.7 years. Type 2 diabetes [P = 0.02, hazard ratios (HR) 2.43, confidence interval (CI) 1.13-5.22] and CFR (P = 0.001, HR 0.15, CI 0.05-0.45) were independent predictors of mortality. A CFR ≤ 1.5 had a significantly (P < 0.0001) higher mortality of 49 vs. 10% in patients with CFR > 1.5 over the 4 year follow-up period. CFR determined by MCE is a powerful predictor of mortality in patients with heart failure.

  10. Atherosclerosis and cerebral ischemic attacks: intakes of cerebrography with xenon133 inhaled and platelet tests in the diagnosis, clinical and therapeutic monitoring; the preventive role of dipyridamole.

    PubMed

    Solvay, H; Kahn, M; Selosse, P; Carlier, J; Cloarec, M; Delwiche, J P; Fenollar, J

    1984-11-01

    A study of patients to develop the significance of the role of the blood platelets in the recurrence of transient cerebral ischemic attacks in patients with cerebral atheromatous, develop the effectiveness of dipyridamole in the prophylactic therapeutic regimen. In the group treated with dipyridamole, a 76.3% clinical improvement was recorded (mean increases of 11.2 ml/min. and 11.4 ml/min. of the cerebral hemispheric flows), 15.8% of cases stabilized (mean increases of 1.7 ml/min. and 1.2 ml/min.) and 7.9% failures (mean decreases of 10.4 ml/min. and 14.3 ml/min.) of these same flows. The cerebrography with xenon133 inhaled as well as the platelet tests used, constitute unfailing means of diagnosing and monitoring the clinical development.

  11. Comparison of rubidium-82 positron emission tomography and thallium-201 SPECT imaging for detection of coronary artery disease

    SciTech Connect

    Stewart, R.E.; Schwaiger, M.; Molina, E.; Popma, J.; Gacioch, G.M.; Kalus, M.; Squicciarini, S.; al-Aouar, Z.R.; Schork, A.; Kuhl, D.E. )

    1991-06-15

    The diagnostic performance of rubidium-82 (Rb-82) positron emission tomography (PET) and thallium-201 (Tl-201) single-photon emission-computed tomography (SPECT) for detecting coronary artery disease was investigated in 81 patients (52 men, 29 women). PET studies using 60 mCi of Rb-82 were performed at baseline and after intravenous infusion of 0.56 mg/kg dipyridamole in conjunction with handgrip stress. Tl-201 SPECT was performed after dipyridamole-handgrip stress and, in a subset of patients, after treadmill exercise. Sensitivity, specificity and overall diagnostic accuracy were assessed using both visually and quantitatively interpreted coronary angiograms. The overall sensitivity, specificity and accuracy of PET for detection of coronary artery disease (greater than 50% diameter stenosis) were 84, 88 and 85%, respectively. In comparison, the performance of SPECT revealed a sensitivity of 84%, specificity of 53% (p less than 0.05 vs PET) and accuracy of 79%. Similar results were obtained using either visual or quantitative angiographic criteria for severity of coronary artery disease. In 43 patients without prior myocardial infarction, the sensitivity for detection of disease was 71 and 73%, respectively, similar for both PET and SPECT. There was no significant difference in diagnostic performance between imaging modalities when 2 different modes of stress (exercise treadmill vs intravenous dipyridamole plus handgrip) were used with SPECT imaging. Thus, Rb-82 PET provides improved specificity compared with Tl-201 SPECT for identifying coronary artery disease, most likely due to the higher photon energy of Rb-82 and attenuation correction provided by PET. However, post-test referral cannot be entirely excluded as a potential explanation for the lower specificity of Tl-201 SPECT.

  12. Fenofibrate and dipyridamole treatments in low-doses either alone or in combination blunted the development of nephropathy in diabetic rats.

    PubMed

    Balakumar, Pitchai; Varatharajan, Rajavel; Nyo, Ying Hui; Renushia, Raja; Raaginey, Devarajan; Oh, Ann Nah; Akhtar, Shaikh Sohrab; Rupeshkumar, Mani; Sundram, Karupiah; Dhanaraj, Sokkalingam A

    2014-12-01

    Low-doses of fenofibrate and dipyridamole have pleiotropic renoprotective actions in diabetic rats. This study investigated their combined effect relative to their individual treatments and lisinopril in rats with diabetic nephropathy. Streptozotocin (55mg/kg, i.p., once)-administered diabetic rats were allowed for 10 weeks to develop nephropathy. Diabetic rats after 10 weeks developed nephropathy with discernible renal structural and functional changes as assessed in terms of increase in kidney weight to body weight ratio (KW/BW), and elevations of serum creatinine, urea and uric acid, which accompanied with elevated serum triglycerides and decreased high-density lipoproteins. Hematoxylin-eosin, periodic acid Schiff and Masson trichrome staining confirmed renal pathological changes in diabetic rats that included glomerular capsular wall distortion, mesangial cell expansion, glomerular microvascular condensation, tubular damage and degeneration and fibrosis. Low-dose fenofibrate (30mg/kg, p.o., 4 weeks) and low-dose dipyridamole (20mg/kg, p.o., 4 weeks) treatment either alone or in combination considerably reduced renal structural and functional abnormalities in diabetic rats, but without affecting the elevated glucose level. Fenofibrate, but not dipyridamole, significantly prevented the lipid alteration and importantly the uric acid elevation in diabetic rats. Lisinopril (5mg/kg, p.o., 4 weeks, reference compound), prevented the hyperglycemia, lipid alteration and development of diabetic nephropathy. Lipid alteration and uric acid elevation, besides hyperglycemia, could play key roles in the development of nephropathy. Low-doses of fenofibrate and dipyridamole treatment either alone or in combination markedly prevented the diabetes-induced nephropathy. Their combination was as effective as to their individual treatment, but not superior in preventing the development of diabetic nephropathy.

  13. A flow-through optosensing device with fluorimetric transduction for rapid and sensitive determination of dipyridamole in pharmaceuticals and human plasma.

    PubMed

    Ruiz-Medina, A; Fernández-de Córdova, M L; Molina-Díaz, A

    2001-07-01

    A flow-through optosensor with fluorimetric transduction has been prepared for the sensitive and selective determination of dipyridamole in aqueous solutions and biological fluids. The method is based on a monochannel flow-injection analysis system using Sephadex QAE A-25 resin, placed into a Hellma 176-QS fluorimetric flow-through cell, as an active sorbing substrate. The native fluorescence of dipyridamole fixed on the solid sorbent is continuously monitored at wavelengths of 305 and 490 nm for excitation and emission, respectively. After obtaining the maximum fluorescence intensity, the eluent solution (KH(2)PO(4)/NaOH buffer solution, c(T)=0.05 mol l(-1), pH 6.0) is allowed to reach the flow cell, the analyte is removed, and the resin support is regenerated. When an NaOH (10(-4) mol l(-1))/NaCl (0.1 mol l(-1)) solution is used as carrier solution, at a flow-rate of 1.56 ml min(-1), the sensor responds linearly in the measuring range of 10-500 microg l(-1) with a detection limit of 0.94 microg l(-1) and a throughput of 22 samples per hour (300 microl of sample volume). The relative standard deviation for ten independent determinations (200 microg l(-1)) is less than 0.82%. The method was satisfactorily applied to the determination of dipyridamole in pharmaceutical preparations and human plasma.

  14. Ineffectiveness of dipyridamole SPECT thallium imaging as a screening technique for coronary artery disease in patients with end-stage renal failure

    SciTech Connect

    Marwick, T.H.; Steinmuller, D.R.; Underwood, D.A.; Hobbs, R.E.; Go, R.T.; Swift, C.; Braun, W.E. )

    1990-01-01

    The efficacy of dipyridamole single photon emission computed tomography (SPECT) thallium as a screening test for coronary artery disease (CAD), was studied in 45 patients with end-stage renal failure undergoing evaluation for renal transplantation. Coronary arteriography, dipyridamole SPECT thallium imaging and clinical follow-up were performed in all patients. Nineteen patients (42%) had an obstruction of 50% or more in at least one coronary artery. Fourteen patients had a positive thallium scan, but 7 of these were false-positives (sensitivity 37%, specificity 73%). The sensitivity was considerably lower than that quoted for non-ESRF patients in the literature, and significantly lower than a control group of 19 patients without ESRF having comparable severity and distribution of CAD. Five of the 6 patients who died of cardiac causes over a mean follow-up period of 25 months had normal thallium imaging, but all had significant coronary artery disease at cardiac catheterization. Dipyridamole SPECT thallium imaging has not proved a useful screening test for angiographically significant CAD, and does not predict cardiac prognosis in this population.

  15. European Stroke Prevention Study 2: A study of low-dose acetylsalicylic acid and of high dose dipyridamole in secondary prevention of cerebro-vascular accidents.

    PubMed

    1995-11-01

    In spite of some data being added to our knowledge of the effect of antiplatelets in secondary prevention of brain ischemic lesion in recent years, the main reasons to perform a second European Stroke Prevention Study (ESPS 2), which started in 1987-1988, were: (a) clarify the relative roles of aspirin (ASA) and dipyridamole (DP) alone or in combination; (b) confirm the efficacy of small doses of ASA and, so doing, decrease the number of drop-outs due to ASA side effects; (c) join information to the effect of antiplatelets in complete stroke. General characteristics of the sample of 6602 patients are presented and compared with other major trials and series. The patients in the four treatment arms (aspirin, dipyridamole, aspirin + dipyridamole and placebo) are compared. The more relevant features and risk factors known to influence long term prognosis are described and discussed. The small proportion of patients included with TIA (23.7%) and the comparability among treatment groups are stressed. No relevant differences have been found, among groups, on the sex or age distribution, prevalence of hypertension, diabetes, previous vascular events or atrial fibrillation, nor in the characteristics of the accident leading to the inclusion in trial.

  16. Usefulness of coronary flow reserve over regional wall motion when added to dual-imaging dipyridamole echocardiography.

    PubMed

    Rigo, Fausto; Richieri, Margherita; Pasanisi, Emilio; Cutaia, Valeria; Zanella, Carlo; Della Valentina, Patrizia; Di Pede, Francesco; Raviele, Antonio; Picano, Eugenio

    2003-02-01

    Vasodilator stress echocardiography allows semi-simultaneous imaging of left anterior descending (LAD) coronary flow and regional wall function. To assess the relative (and additive?) value of regional flow and function for noninvasive identification of angiographically assessed LAD disease in patients with chest pain syndrome, we studied 230 consecutive in-hospital patients (134 men, aged 63.5 +/- 11 years) with chest pain syndrome and normal regional and global left ventricular function. All patients underwent stress echocardiography with dipyridamole (up to 0.84 mg/kg over 10 minutes), including wall motion analysis by 2-dimensional echocardiography and coronary flow reserve (CFR) evaluation of the LAD artery by Doppler, with or without contrast injection. A new regional wall motion abnormality in >or=2 contiguous segments was required for 2-dimensional echocardiographic positivity. CFR was evaluated as the ratio of dipyridamole to peak diastolic coronary blood flow velocity at rest. All patients underwent coronary angiography within 60 days; a quantitatively assessed diameter reduction >50% of the LAD artery was considered significant. Of the 230 patients, 70 had LAD disease. A regional wall motion abnormality in LAD territory was present in 52 patients, and reduced CFR (<1.9) in 62 patients. Sensitivity for detecting LAD disease was 74% for 2-dimensional echocardiography (95% confidence interval [CI] 64% to 84%) and 81% for CFR <1.9 (95% CI 72% to 90%); specificity was 91% (95% CI 87% to 96%) for 2-dimensional echocardiography and 84% for CFR (95% CI 79% to 90%). Accuracy was 86% for 2-dimensional echocardiography (95% CI 82% to 91%) and 83.5% for CFR (95% CI 79% to 88%). When 2-dimensional echocardiography and CFR criteria were considered, sensitivity increased to 93% (95% CI 87% to 99%), with 80.6% specificity (95% CI 74.5% to 86.7%). CFR was assessed during vasodilator stress echocardiography. Its diagnostic accuracy for detecting LAD disease was comparable

  17. Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres.

    PubMed

    Jogiya, Roy; Makowski, Markus; Phinikaridou, Alkystsis; Patel, Ashish S; Jansen, Christian; Zarinabad, Niloufar; Chiribiri, Amedeo; Botnar, Rene; Nagel, Eike; Kozerke, Sebastian; Plein, Sven

    2013-07-21

    Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported. Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting. Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84). First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

  18. Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres

    PubMed Central

    2013-01-01

    Background Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported. Methods Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting. Results Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84). Conclusion First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies. PMID:23870734

  19. Noninvasive prediction of coronary artery disease progression by comparison of serial exercise electrocardiography and dipyridamole stress echocardiography.

    PubMed

    Rodriguez, Olaf; Picano, Eugenio; Fedele, Silvio; Morelos, Martha; Marzilli, Mario

    2002-04-01

    The possibility of noninvasive prediction of angiographically assessed coronary artery disease (CAD) progression by comparison of serial studies of exercise electrocardiography (EET) and dipyridamole stress echocardiography (DET) is not known. To assess the relative value of EET and DET in predicting angiographically assessed progression of CAD. From the Institute of Clinical Physiology, National Research Council, Pisa Italy stress echo data bank (1983-1998), we selected 46 patients with two repeated EET, DET and coronary angiography (CA) in two different hospital admissions (46+/-30 months). A priori, angiographic progressors were defined as any stenosis progression to occlusion and/or any stenosis >30% with >20% stenosis progression measured by visual and quantitative CA. EET progressors were defined as a previous negative test becoming positive or as a positive test with decrease in ischemic threshold response in the second test. DET progressors were defined as previous negative test becoming positive or as a positive test with a more severe ischemic response in the second test. Angiographic progressors were 31/46 patients (67%) and angiographic nonprogressors were 15/46 (33%). When angiography was taken as the gold standard, there were no differences in sensitivity for EET and DET (87 vs. 87%). Specificity was significantly higher for DET (93 vs. 40% p =< 0.001). By kappa statistics DET had a good concordance (kappa = 0.768) and EET a poor concordance (kappa = 0.299) with angiographic progression. DET is more accurate than EET at predicting angiographically assessed CAD progression.

  20. Preparation and characterization of dipyridamole solid dispersions for stabilization of supersaturation: effect of precipitation inhibitors type and molecular weight.

    PubMed

    Vora, Chintan; Patadia, Riddhish; Mittal, Karan; Mashru, Rajashree

    2016-11-01

    Dipyridamole (DPL) is a weakly basic BCS class II drug which precipitates upon entering into intestine leading to pH dependant and variable absorption. Thus, research envisaged focuses on developing formulations that maintain supersaturation following upon acid to neutral pH transition. In an endeavor to accomplish the objective, solid dispersion (SD) with hydroxypropylmethyl cellulose (HPMC) and polyvinylpyrrolidone (PVP) was prepared by a quench cooling method. The three molecular weight grades of HPMC (HPMC E5, HPMC E15 and HPMC E50) and two molecular weight grades of PVP (PVP K30 and PVP K90) were investigated to observe effect of increasing molecular weight on stabilizing DPL supersaturated solutions. Equilibrium solubility studies revealed increase in solubility with both HPMC and PVP with greater benefit from HPMC. In vitro supersaturated dissolution results demonstrated that HPMC formulations provided greater degree and extent of supersaturation as compared to PVP formulations. The formulation with HPMC E50 provided maximum stabilization to supersaturation upon acid to neutral pH transition. Moreover, the effect of increase in molecular weight was more pronounced in HPMC rather than PVP. Stronger interactions were observed for DPL with HPMC, while no interaction was observed with PVP which was evident from Fourier transform infra-red studies. Differential scanning calorimetry and powder X-ray diffraction studies revealed the amorphous state of DPL in SD.

  1. Dipyridamole potentiated the trypanocidal effect of nifurtimox and improved the cardiac function in NMRI mice with acute chagasic myocarditis

    PubMed Central

    Santeliz, Sonia; Caicedo, Peter; Giraldo, Elidiosmar; Alvarez, Carmen; Yustiz, María-Daniela; Rodríguez-Bonfante, Claudina; Bonfante-Rodríguez, Romina; Bonfante-Cabarcas, Rafael

    2017-01-01

    BACKGROUND As chronic Chagas disease does not have a definitive treatment, the development of alternative therapeutic protocols is a priority. Dipyridamole (DPY) is an alternative to counteract the pathophysiological phenomena involved in Chagas cardiomyopathy. OBJECTIVE To evaluate the therapeutic efficacy of DPY associated with nifurtimox (Nfx) in epimastigote axenic cultures and in mice with acute Chagas disease. METHODS NMRI adult male mice were divided into nine groups: three healthy and six Trypanosoma cruzi-infected groups. Mice received vehicle, Nfx or DPY, alone or combined. The doses assayed were Nfx 10 and 40 mg/kg and DPY 30 mg/kg. The treatment efficacy was evaluated by clinical, electrocardiographic, parasitological, biochemical and histopathological methods. FINDINGS In vitro, DPY and Nfx had a trypanocidal effect with IC50 values of 372 ± 52 and 21.53 ± 2.13 µM, respectively; DPY potentiated the Nfx effect. In vivo, Nfx (40 mg/kg) with or without DPY had a therapeutic effect, which was reflected in the 84-92% survival rate and elimination of parasitaemia and heart tissue amastigotes. Nfx (10 mg/kg) had a subtherapeutic effect with no survival and persistence of amastigotes, inflammation and fibrosis in heart tissue; adding DPY increased the survival rate to 85%, and all tested parameters were significantly improved. MAIN CONCLUSION DPY has a trypanocidal effect in vitro and enhances the Nfx therapeutic effect in an in vivo murine model. PMID:28902285

  2. Dipyridamole potentiated the trypanocidal effect of nifurtimox and improved the cardiac function in NMRI mice with acute chagasic myocarditis.

    PubMed

    Santeliz, Sonia; Caicedo, Peter; Giraldo, Elidiosmar; Alvarez, Carmen; Yustiz, María-Daniela; Rodríguez-Bonfante, Claudina; Bonfante-Rodríguez, Romina; Bonfante-Cabarcas, Rafael

    2017-09-01

    As chronic Chagas disease does not have a definitive treatment, the development of alternative therapeutic protocols is a priority. Dipyridamole (DPY) is an alternative to counteract the pathophysiological phenomena involved in Chagas cardiomyopathy. To evaluate the therapeutic efficacy of DPY associated with nifurtimox (Nfx) in epimastigote axenic cultures and in mice with acute Chagas disease. NMRI adult male mice were divided into nine groups: three healthy and six Trypanosoma cruzi-infected groups. Mice received vehicle, Nfx or DPY, alone or combined. The doses assayed were Nfx 10 and 40 mg/kg and DPY 30 mg/kg. The treatment efficacy was evaluated by clinical, electrocardiographic, parasitological, biochemical and histopathological methods. In vitro, DPY and Nfx had a trypanocidal effect with IC50 values of 372 ± 52 and 21.53 ± 2.13 µM, respectively; DPY potentiated the Nfx effect. In vivo, Nfx (40 mg/kg) with or without DPY had a therapeutic effect, which was reflected in the 84-92% survival rate and elimination of parasitaemia and heart tissue amastigotes. Nfx (10 mg/kg) had a subtherapeutic effect with no survival and persistence of amastigotes, inflammation and fibrosis in heart tissue; adding DPY increased the survival rate to 85%, and all tested parameters were significantly improved. DPY has a trypanocidal effect in vitro and enhances the Nfx therapeutic effect in an in vivo murine model.

  3. The influence of agent delivery mode on cardiomyocyte injury induced by myocardial contrast echocardiography in rats.

    PubMed

    Miller, Douglas L; Dou, Chunyan; Armstrong, William F

    2005-09-01

    Myocardial contrast echocardiography (MCE) can induce bioeffects in rat hearts by local activation of the contrast agent gas bodies. This study was designed to examine the influence of agent delivery mode on the magnitude of cardiomyocyte injury. A total of 69 hairless rats were anesthetized and mounted vertically in a water bath. Evans blue dye was injected as vital stain for cardiomyocyte injury. Definity contrast agent was diluted in saline and injected via tail vein at 20 or 80 microL/kg in bolus or infusion mode. In 12 rats, 0.57 mg/kg dipyridamole was given to simulate a stress test. MCE in a short axis view with 1:4 or 1:16 ECG triggering was performed at 1.5 MHz for 5 or 20 min. The peak rarefactional pressure amplitude was set to 1.1 or 2.0 MPa. Premature beats were counted from the ECG record. Evans blue fluorescent cells were counted on frozen sections from the center of the scan plane of heart samples obtained 24 h postMCE. Infusion of the contrast agent led to more cardiomyocyte injury than did bolus injection. Dipyridamole stress also increased the effect. Varying the infusion rate or trigger interval was less important than the overall dosage during scanning. Exposure at 1.1 MPa and 80 microL/kg yielded significant cell killing relative to shams. Premature beats generally followed the same trends as cell injury, except that lower infusion rates tended to increase this effect. Contrast agent delivery mode, as well as dose and peak rarefactional pressure amplitude, has a significant influence on the bioeffects potential of MCE.

  4. Periodontitis and myocardial hypertrophy.

    PubMed

    Suzuki, Jun-Ichi; Sato, Hiroki; Kaneko, Makoto; Yoshida, Asuka; Aoyama, Norio; Akimoto, Shouta; Wakayama, Kouji; Kumagai, Hidetoshi; Ikeda, Yuichi; Akazawa, Hiroshi; Izumi, Yuichi; Isobe, Mitsuaki; Komuro, Issei

    2017-04-01

    There is a deep relationship between cardiovascular disease and periodontitis. It has been reported that myocardial hypertrophy may be affected by periodontitis in clinical settings. Although these clinical observations had some study limitations, they strongly suggest a direct association between severity of periodontitis and left ventricular hypertrophy. However, the detailed mechanisms between myocardial hypertrophy and periodontitis have not yet been elucidated. Recently, we demonstrated that periodontal bacteria infection is closely related to myocardial hypertrophy. In murine transverse aortic constriction models, a periodontal pathogen, Aggregatibacter actinomycetemcomitans markedly enhanced cardiac hypertrophy with matrix metalloproteinase-2 activation, while another pathogen Porphyromonas gingivalis (P.g.) did not accelerate these pathological changes. In the isoproterenol-induced myocardial hypertrophy model, P.g. induced myocardial hypertrophy through Toll-like receptor-2 signaling. From our results and other reports, regulation of chronic inflammation induced by periodontitis may have a key role in the treatment of myocardial hypertrophy. In this article, we review the pathophysiological mechanism between myocardial hypertrophy and periodontitis.

  5. Effect of adjunctive dipyridamole to DAPT on platelet function profiles in stented patients with high platelet reactivity. The result of the ACCEL-DIP Study.

    PubMed

    Park, Y; Jeong, Y-H; Tantry, U S; Ahn, J H; Kim, K H; Koh, J-S; Park, J-R; Hwang, S-J; Kwak, C H; Hwang, J-Y; Gurbel, P A

    2014-12-01

    Adjunctive use of phosphodiesterase (PDE) inhibitor can enhance antiplatelet and vasoprotective properties in patients with cardiovascular disease. The aim of this study was to evaluate the impact of PDE5 inhibitor dipyridamole on platelet function in stented patients with high platelet reactivity (HPR) during dual antiplatelet therapy (DAPT) with aspirin and clopidogrel. Patients with HPR after 600-mg clopidogrel loading were randomly assigned to adjunctive dipyridamole 75 mg twice daily to standard DAPT (DIP group; n = 45) or double-dose clopidogrel of 150 mg daily (DOUBLE group; n = 46) for 30 days. Platelet function was assessed at baseline and 30-day follow-up with platelet reactivity index (PRI) by vasodilator-stimulated phosphoprotein-phosphorylation (VASP-P) assay and platelet aggregation (PA) by light transmittance aggregometry (LTA). Primary endpoint was PRI at 30-day follow-up. HPR was defined as PRI > 50%. Baseline platelet function did not differ between the groups. Following 30-day therapy, platelet function was significantly reduced in the DIP and DOUBLE groups (all p-values ≤ 0.004 and ≤ 0.068, respectively). PRI values were not significantly different between the two groups (mean difference: 3.1%; 95% confidence interval: -2.8% to 9.0%: p = 0.295). PA values and prevalence of HPR were similar between the groups. However, a significant number of patients still exhibited HPR in the DIP (75.6%) and DOUBLE (67.4%) groups. In conclusion, among stented HPR patients, adding dipyridamole to DAPT does not reduce platelet reactivity and prevalence of HPR compared with double-dose clopidogrel therapy, and therefore both strategies are inadequate to overcome HPR.

  6. Leakage of potassium from red blood cells following gamma ray irradiation in the presence of dipyridamole, trolox, human plasma or mannitol.

    PubMed

    Hirayama, Junichi; Abe, Hideki; Azuma, Hiroshi; Ikeda, Hisami

    2005-07-01

    Transfusion-associated graft-versus-host disease (TA-GVHD) is a fatal complication of blood transfusion resulting from the contamination of blood products by leukocytes. In order to prevent this disease, gamma or X-ray irradiation of blood components,which can inactivate leukocytes, is currently used. However, the minimal doses needed to destroy lymphocytes promote the leakage of potassium from red blood cells (RBCs), which can induce other side effects, such as hyperpotassemia and cardiac arrest. The reactive oxygen species (ROS) generated by the irradiation of aqueous solutions may accelerate the leakage through oxidation of the RBC membrane. Here we studied the effect of dipyridamole, Trolox, human plasma or mannitol on the leakage of potassium from RBCs following irradiation. RBC preparations (hematocrit; 30%) containing antioxidants were irradiated at 30 Gy and stored at 4 degrees C for 7 d. The leakage of potassium from the RBCs caused by the irradiation was significantly suppressed by dipyridamole (more than 50 microM), Trolox (more than 5 mM) or human plasma (50%). Mannitol (80 mM) is used to inhibit hemolysis as a constituent of MAP solution, which is a solution used for the storage of RBC products in Japan. Here it was clarified that the leakage of potassium from not only irradiated but also non-irradiated RBCs was unexpectedly promoted by mannitol. The amount of mannitol in MAP solution may have to be reconsidered. The osmotic pressure of the RBC preparation increased in a manner dependent on the concentration of mannitol. The elevated osmotic pressure may promote the leakage. In conclusion, although antioxidants have the potential to suppress the leakage of potassium ascribed to the irradiation, the extent of the suppression (10-20%) by dipyridamole (DPM), Trolox or human plasma seems insufficient for the clinical use of these agents as an additive for MAP solution.

  7. [Relationship between ventricular arrhythmias and myocardial fatty acid metabolism in patients with coronary heart disease: evaluation using iodine-123 beta-methyl-p-iodophenyl-pentadecanoic acid].

    PubMed

    Mori, H; Sakamoto, T; Ueda, Y; Yano, K

    1999-08-01

    The effect of metabolic abnormalities of myocardial fatty acids on ventricular arrhythmias was evaluated by myocardial imaging with iodine-123 beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) in 27 patients with coronary heart disease. The disturbance of myocardial blood flow was also evaluated using thallium-201 (Tl). The patients were divided into 2 groups based on the character of the premature ventricular contractions: Group A: number of contractions > or = 120 per day and/or consecutive contractions (n = 9, mean age 63.7 yr), and Group B, number of contractions < 120 per day and no consecutive contractions (n = 18, mean age 64.2 yr). Left ventricular ejection fraction was measured by left ventriculography, and significant coronary artery stenosis was defined as stenosis of 75% or greater. Cardiac scintigraphy was performed using single photon emission computed tomography with BMIPP at rest in 27 patients and in the early phase (early Tl) and delayed phase of Tl (delayed Tl) in 20 patients. BMIPP and Tl uptakes were scored as 0: absent, 1: moderately reduced, 2: mildly reduced and 3: normal in 7 segments of the left ventricular wall and then the total scores were calculated in each patient. Ejection fraction significantly correlated with the scores of BMIPP, and early and delayed Tl(p < 0.001, respectively), although the ejection fraction in Group A was significantly less than in Group B (51.2 +/- 16.7% vs 68.2 +/- 14.4%, p < 0.02). The BMIPP scores in Group A were significantly less than those in Group B (14.2 +/- 4.3 vs 17.2 +/- 3.1, p < 0.05), but the early and delayed Tl scores in Group A were not significantly different compared with those in Group B. The BMIPP scores showed no significant differences between the patients with and without significant coronary artery stenosis, but the early and delayed Tl scores in the patients with stenosis were significantly less than those in patients without stenosis (early Tl: 19.8 +/- 2.6 vs 16.8 +/- 2.8, p < 0

  8. Comparison of single-photon emission computed tomographic (SPECT) myocardial perfusion imaging with thallium-201 and technetium-99m sestamibi in dogs.

    PubMed

    Leon, A R; Eisner, R L; Martin, S E; Schmarkey, L S; Aaron, A M; Boyers, A S; Burnham, K M; Oh, D J; Patterson, R E

    1992-12-01

    The purpose of the present study was to compare single-photon emission computed tomographic (SPECT) myocardial images of technetium-99m (Tc-99m) sestamibi and thallium-201 (Tl-201) isotopes in the same dog undergoing partial coronary occlusion during pharmacologic vasodilation. To date, no controlled study has been reported comparing SPECT Tc-99m sestamibi with SPECT Tl-201 imaging during stress with anatomic and physiologic standards. Mongrel dogs were anesthetized with chloralose and instrumented to record left anterior descending coronary blood flow and aortic pressure. Partial coronary occlusion with a hydraulic cuff reduced coronary vascular conductance, which is equal to the coronary blood flow normalized to aortic pressure during peak vasodilation with intravenous adenosine. Each dog received 5 mCi of Tl-201, then 30 mCi of Tc-99m sestamibi during partial coronary occlusion at peak vasodilation. Tomographic myocardial imaging was performed in a 180 degrees anterior arc scan for 33.5 min, first with Tl-201, and later, without moving the dog, for 33.5 min with Tc-99m sestamibi. Postmortem staining defined the region underperfused because of its dependence on the artery that was partially occluded. In seven dogs with moderate reduction in coronary blood flow, coronary vascular conductance decreased with partial coronary occlusion (47 +/- 12%) during Tl-201 imaging and (47 +/- 8%, p = NS) during Tc-99m sestamibi imaging. The underperfused region was 23.9 +/- 6.4% of total left ventricular mass. Counts in the defects were 39% higher (0.86 +/- 0.08 of normal counts) for Tc-99m sestamibi than for Tl-201 (0.64 +/- 0.09 of normal counts, p < 0.001), and the defect on SPECT Tc-99m sestamibi images occupied only a fraction (0.37 +/- 0.30) of the area of the defect on the Tl-201 images of the same dog. Bull's-eye displays constructed from the pathologic slices showed that the Tl-201 defect size was closer to the underperfused region of the left ventricular mass

  9. [Depression and myocardial infaction].

    PubMed

    Testuz, A

    2009-03-04

    Several works show an association between depression and the occurence of a first myocardial infarction. Depression after myocardial infarction seems to be a marker of poorer outcome, regardless of other risk factors or severity of the myocardial infarction. Dysautonomia and alteration of platelet activation are a few physiopathological changes shared by both affections, through which they might be related. Treatment of depression is not associated with better cardiovascular outcome, but selective serotonin reuptake inhibitors have been shown safe and efficient among patients with coronary heart disease. Cognitivo-comportemental approach and cardiovascular rehabilitation program after myocardial infarction also play a role in improving quality of life of the depressed patient with coronary heart disease.

  10. Comparison of 8-frame and 16-frame thallium-201 gated myocardial perfusion SPECT for determining left ventricular systolic and diastolic parameters.

    PubMed

    Kurisu, Satoshi; Sumimoto, Yoji; Ikenaga, Hiroki; Watanabe, Noriaki; Ishibashi, Ken; Dohi, Yoshihiro; Fukuda, Yukihiro; Kihara, Yasuki

    2017-07-01

    The myocardial perfusion single photon emission computed tomography synchronized with the electrocardiogram (gated SPECT) has been widely used for the assessment of left ventricular (LV) systolic and diastolic functions using Quantitative gated SPECT. The aim of this study was to compare the effects of 8-frame and 16-frame thallium-201 (Tl-201) gated SPECT for determining LV systolic and diastolic parameters. The study population included 42 patients with suspected coronary artery disease who underwent gated SPECT by clinical indication. LV systolic and diastolic parameters were assessed on 8-frame and 16-frame gated SPECT. There were good correlations in end-diastolic volume (r = 0.99, p < 0.001), end-systolic volume (ESV) (r = 0.97, p < 0.001) and ejection fraction (EF) (r = 0.95, p < 0.001) between 8-frame and 16-frame gated SPECT. Bland-Altman plot showed a significant negative slope of -0.08 in EDV indicating a larger difference for larger EDV. Eight-frame gated SPECT overestimated ESV by 2.3 ml, and underestimated EF by -4.2% than 16-frame gated SPECT. There were good correlations in peak filling rate (PFR) (r = 0.87, p < 0.001), one third mean filling rate (r = 0.87, p < 0.001) and time to PFR (r = 0.61, p < 0.001) between 8-frame and 16-frame gated SPECT. Eight-frame gated SPECT underestimated PFR by -0.22 than 16-frame gated SPECT. Eight-frame gated SPECT estimated as much MFR/3 and TPFR as 16-frame gated SPECT. According to the data, the study suggested that 8-frame Tl-201 gated SPECT could underestimate systolic and/or diastolic parameter when compared with 16-frame gated SPECT.

  11. An investigation into the crystallization tendency/kinetics of amorphous active pharmaceutical ingredients: A case study with dipyridamole and cinnarizine.

    PubMed

    Baghel, Shrawan; Cathcart, Helen; Redington, Wynette; O'Reilly, Niall J

    2016-07-01

    Amorphous drug formulations have great potential to enhance solubility and thus bioavailability of BCS class II drugs. However, the higher free energy and molecular mobility of the amorphous form drive them towards the crystalline state which makes them unstable. Accurate determination of the crystallization tendency/kinetics is the key to the successful design and development of such systems. In this study, dipyridamole (DPM) and cinnarizine (CNZ) have been selected as model compounds. Thermodynamic fragility (mT) was measured from the heat capacity change at the glass transition temperature (Tg) whereas dynamic fragility (mD) was evaluated using methods based on extrapolation of configurational entropy to zero [Formula: see text] , and heating rate dependence of Tg [Formula: see text] . The mean relaxation time of amorphous drugs was calculated from the Vogel-Tammann-Fulcher (VTF) equation. Furthermore, the correlation between fragility and glass forming ability (GFA) of the model drugs has been established and the relevance of these parameters to crystallization of amorphous drugs is also assessed. Moreover, the crystallization kinetics of model drugs under isothermal conditions has been studied using Johnson-Mehl-Avrami (JMA) approach to determine the Avrami constant 'n' which provides an insight into the mechanism of crystallization. To further probe into the crystallization mechanism, the non-isothermal crystallization kinetics of model systems were also analysed by statistically fitting the crystallization data to 15 different kinetic models and the relevance of model-free kinetic approach has been established. The crystallization mechanism for DPM and CNZ at each extent of transformation has been predicted. The calculated fragility, glass forming ability (GFA) and crystallization kinetics are found to be in good correlation with the stability prediction of amorphous solid dispersions. Thus, this research work involves a multidisciplinary approach to

  12. Dipyridamole attenuates ischemia reperfusion induced acute kidney injury through adenosinergic A1 and A2A receptor agonism in rats.

    PubMed

    Puri, Nikkita; Mohey, Vinita; Singh, Manjinder; Kaur, Tajpreet; Pathak, Devendra; Buttar, Harpal Singh; Singh, Amrit Pal

    2016-04-01

    Dipyridamole (DYP) is an anti-platelet agent with marked vasodilator, anti-oxidant, and anti-inflammatory activity. The present study investigated the role of adenosine receptors in DYP-mediated protection against ischemia reperfusion-induced acute kidney injury (AKI) in rats. The rats were subjected to bilateral renal ischemia for 40 min followed by reperfusion for 24 h. The renal damage induced by ischemia reperfusion injury (IRI) was assessed by measuring creatinine clearance, blood urea nitrogen, uric acid, plasma potassium, fractional excretion of sodium, and microproteinuria in rats. The oxidative stress in renal tissues was assessed by quantification of thiobarbituric acid-reactive substances, superoxide anion generation, and reduced glutathione level. The hematoxylin-eosin staining was carried out to observe histopathological changes in renal tissues. DYP (10 and 30 mg/kg, intraperitoneal, i.p.) was administered 30 min before subjecting the rats to renal IRI. In separate groups, caffeine (50 mg/kg, i.p.), an adenosinergic A1 and A2A receptor antagonist was administered with and without DYP treatment before subjecting the rats to renal IRI. The ischemia reperfusion-induced AKI was demonstrated by significant changes in serum as well as urinary parameters, enhanced oxidative stress, and histopathological changes in renal tissues. The administration of DYP demonstrated protection against AKI. The prior treatment with caffeine abolished DYP-mediated reno-protection suggesting role of A1 and A2A adenosine receptors in DYP-mediated reno-protection in rats. It is concluded that adenosine receptors find their definite involvement in DYP-mediated anti-oxidative and reno-protective effect against ischemia reperfusion-induced AKI.

  13. Transthoracic measurement of left coronary artery flow reserve improves the diagnostic value of routine dipyridamole-atropine stress echocardiogram

    PubMed Central

    Wejner-Mik, Paulina; Nouri, Aria; Szymczyk, Ewa; Krzemińska-Pakuła, Maria; Lipiec, Piotr

    2013-01-01

    Introduction We hypothesized that coronary flow reserve (CFR) in the left anterior descending artery (LAD) can be effectively measured during an accelerated dipyridamole-atropine stress echocardiography (DASE) protocol to improve the diagnostic performance of the test. Material and methods In 64 patients with suspected or known coronary artery disease scheduled for coronary angiography DASE with concomitant CFR measurement in LAD was performed. Results Coronary flow reserve measurement and calculation were feasible in 83% of patients. The positive predictive value of undetectable LAD flow was 81% for severe LAD disease. Measured values of CFR were in the range 1.3–4.1 (mean: 2.2 ±0.7). Significantly lower CFR was found in patients with LAD disease (1.97 ±0.62 vs. 2.55 ±0.57, p = 0.0015). The optimal cutoff for detecting ≥ 50% stenosis was CFR ≤ 2.1 (ROC AUC 0.776), corresponding with 68% sensitivity and 84% specificity. In patients with negative DASE results 67% of patients with LAD disease had abnormal CFR, whereas in patients with a positive DASE result 92% of patients with normal LAD had normal CFR. The DASE diagnostic accuracy for the detection of coronary artery disease (CAD) increased from 75% to 85% when CFR measurement was added to wall motion abnormality (WMA) analysis. No test with both abnormalities was false positive for the detection of coronary disease. Conclusions Incorporation of CFR measurement into WMA-based stress echocardiography is feasible even in an accelerated DASE protocol and can be translated into an approximate gain of 10% in overall test accuracy. PMID:24273560

  14. Myocardial Noncompaction Presenting With Myocardial Bridge

    PubMed Central

    Shen, Yuechun; Li, Xinchun; Lu, Dongfeng; Xiao, Aiyi; Li, Jun

    2015-01-01

    Abstract Myocardial noncompaction, namly isolated noncompaction of the left ventricular myocardium (NVM), is a rare congenital disease. It can be either seen in the absence of other cardiac anomalies, or associated with other congenital cardiac defects, mostly stenotic lesions of the left ventricular outflow tract. A myocardial bridge (MB) is thought being associated with coronary heart disease, such as coronary spasm, arrhythmia, and so on. The significance of MB in association with other congenital cardiac conditions is unknown. We report a novel case who was presented NVM and MB. A 34-year-old man complained of chest prickling-like pain and dizzy for 1 year. His blood pressure was 110/70 mm Hg. Echocardiograph revealed increased trabeculations below the level of papillary muscle of left ventricle (LV); deep intertrabecular recesses in the endocardial wall of LV particularly in apex free wall; and LV ejection fraction of 57%. A coronary computerized tomography scan showed that part, 38.9 cm, of left descending artery tunnel was surrounding by cardiac muscles rather than resting on top of the myocardium. The therapeutics interventions included lifestyle cares, agents of anti-ischemia and improvement myocardial cell metabolism. The patient was followed up for 2.6 years, and his general condition was stable. This case indicates that NVM can be developed with MB, and the complete diagnosis of NVM and MB should be made by different image studies. PMID:26356695

  15. Single-photon agents for tumor imaging: 201Tl, 99mTc-MIBI, and 99mTc-tetrofosmin.

    PubMed

    Fukumoto, Mitsutaka

    2004-04-01

    This review aims at fostering comprehension and knowledge not only for expert physicians who can skillfully handle various techniques for tumor imaging but also for young practitioners in the field of nuclear medicine. As image processing software and hardware become smaller, faster and better, SPECT will adapt and incorporate these advances. A principal advantage of SPECT over PET is the more widespread availability of the equipment and lower cost for the introduction of the system in community-based facilities. Moreover, SPECT has become less dependent on a limited number of acknowledged experts for its interpretation owing to a variety of handy computer tools for imaging analyses. The increasing use of PET in tumor imaging is not necessarily proportional to the decline of SPECT. General physicians' attention to SPECT technology would also increase more by evoking their interest in "tracer imaging."

  16. Thallium-201 imaging in a patient with mid-ventricular hypertrophic obstructive cardiomyopathy

    SciTech Connect

    Wakasugi, S.; Shibata, N.; Kobayashi, T.; Fudemoto, Y.; Hasegawa, Y.; Nakano, S.

    1988-10-01

    Findings specific to mid-ventricular hypertrophic obstructive cardiomyopathy were obtained in a patient by means of /sup 201/Tl planar myocardial scintigraphy. Namely, a myocardial band-like image dividing the left ventricle into two chambers was clearly shown. This was identified as hypertrophic muscle with sphincter-like muscular stenosis at the mid portion of the left ventricle.

  17. Simultaneous Determination of Aspirin, Dipyridamole and Two of Their Related Impurities in Capsules by Validated TLC-Densitometric and HPLC Methods.

    PubMed

    El-Ragehy, Nariman A; Hassan, Nagiba Y; Tantawy, Mahmoud A; Abdelkawy, Mohamed

    2016-08-01

    Aspirin (ASP) and dipyridamole (DIP) are widely used as a combination in pharmaceutical formulations for treatment of strokes. Many of these formulations are containing tartaric acid as an excipient (in DIP pellets formulation for sustained release), which increases the probability of formation of dipyridamole tartaric acid ester impurity (DIP-I). On the other hand, salicylic acid (SAL) is considered to be one of the synthesis impurities and a degradation product of ASP. In this work, two chromatographic methods, namely, TLC-densitometry and HPLC, have been established and validated for simultaneous determination of ASP, DIP, SAL and DIP-I. Good separation was achieved by using silica gel as stationary phase and toluene-methanol-ethyl acetate (2:3:5, by volume) as mobile phase in the case of TLC-densitometry and Zorbax ODS column with mobile phase consisting of phosphate buffer (pH 3.3)-acetonitrile-triethylamine (40:60:0.03, by volume) for HPLC. Influence of different organic solvents in mobile phase composition has been studied to optimize the separation efficiency in TLC densitometry. Moreover, factors affecting the efficiency of HPLC, like pH of the buffer used, organic solvent ratio in the mobile phase and flow rate, have been carefully studied using one variable at a time approach. Finally, the proposed methods were validated as per ICH guidelines.

  18. Quantitative myocardial perfusion SPECT.

    PubMed

    Tsui, B M; Frey, E C; LaCroix, K J; Lalush, D S; McCartney, W H; King, M A; Gullberg, G T

    1998-01-01

    In recent years, there has been much interest in the clinical application of attenuation compensation to myocardial perfusion single photon emission computed tomography (SPECT) with the promise that accurate quantitative images can be obtained to improve clinical diagnoses. The different attenuation compensation methods that are available create confusion and some misconceptions. Also, attenuation-compensated images reveal other image-degrading effects including collimator-detector blurring and scatter that are not apparent in uncompensated images. This article presents basic concepts of the major factors that degrade the quality and quantitative accuracy of myocardial perfusion SPECT images, and includes a discussion of the various image reconstruction and compensation methods and misconceptions and pitfalls in implementation. The differences between the various compensation methods and their performance are demonstrated. Particular emphasis is directed to an approach that promises to provide quantitative myocardial perfusion SPECT images by accurately compensating for the 3-dimensional (3-D) attenuation, collimator-detector response, and scatter effects. With advances in the computer hardware and optimized implementation techniques, quantitatively accurate and high-quality myocardial perfusion SPECT images can be obtained in clinically acceptable processing time. Examples from simulation, phantom, and patient studies are used to demonstrate the various aspects of the investigation. We conclude that quantitative myocardial perfusion SPECT, which holds great promise to improve clinical diagnosis, is an achievable goal in the near future.

  19. Myocardial Lineage Development

    PubMed Central

    Evans, Sylvia M.; Yelon, Deborah; Conlon, Frank L.; Kirby, Margaret L.

    2010-01-01

    The myocardium of the heart is composed of multiple highly specialized myocardial lineages, including those of the ventricular and atrial myocardium, and the specialized conduction system. Specification and maturation of each of these lineages during heart development is a highly ordered, ongoing process involving multiple signaling pathways and their intersection with transcriptional regulatory networks. Here, we attempt to summarize and compare much of what we know about specification and maturation of myocardial lineages from studies in several different vertebrate model systems. To date, most research has focused on early specification, and while there is still more to learn, less is known about factors that promote subsequent maturation of myocardial lineages required to build the functioning adult heart. PMID:21148449

  20. Dual tracer autoradiographic study with thallium-201 and radioiodinated fatty acid in cardiomyopathic hamsters

    SciTech Connect

    Kurata, C.; Kobayashi, A.; Yamazaki, N.

    1989-01-01

    To investigate the usefulness of myocardial scintigraphy with radioiodinated 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) in cardiomyopathy, quantitative dual tracer autoradiographic study with /sup 201/Tl and (/sup 125/I)BMIPP was performed in 27 cardiomyopathic Bio 14.6 Syrian hamsters and eight normal hamsters. Furthermore, 16 Bio 14.6 Syrian hamsters aged 21 days were divided into verapamil-treated (during 70 days) and control groups (respectively, n = 8), and autoradiography with /sup 201/Tl and (/sup 125/I)BMIPP was performed. Quantitative autoradiography demonstrated an uncoupling of /sup 201/Tl and (/sup 125/I)BMIPP distributions and a regional heterogeneity of (/sup 125/I)BMIPP distribution in cardiomyopathic hamsters aged more than 2 mo, while normal hamsters showed only mild heterogeneity of (/sup 125/I)BMIPP distribution without an uncoupling of tracers. Age-matched comparison between normal and cardiomyopathic hamsters (5-8 mo old) demonstrated that a difference between their (/sup 125/I)BMIPP distributions are more marked than that between their /sup 201/Tl distributions. Furthermore, (/sup 125/I)BMIPP visualized effects of verapamil on cardiomyopathy more distinctly than did /sup 201/Tl. In conclusion, myocardial imaging with (/sup 123/I)BMIPP could be useful for investigating cardiomyopathy and evaluating the efficacy of therapeutic intervention in patients with cardiomyopathy.

  1. Myocardial diseases of animals.

    PubMed Central

    Van Vleet, J. F.; Ferrans, V. J.

    1986-01-01

    In this review we have attempted a comprehensive compilation of the cardiac morphologic changes that occur in spontaneous and experimental myocardial diseases of animals. Our coverage addresses diseases of mammals and birds and includes these diseases found in both domesticated and wild animals. A similar review of the myocardial diseases in this broad range of animal species has not been attempted previously. We have summarized and illustrated the gross, microscopic, and ultrastructural alterations for these myocardial diseases; and, whenever possible, we have reviewed their biochemical pathogenesis. We have arranged the myocardial diseases for presentation and discussion according to an etiologic classification with seven categories. These include a group of idiopathic or primary cardiomyopathies recognized in man (hypertrophic, dilated, and restrictive types) and a large group of secondary cardiomyopathies with known causes, such as inherited tendency; nutritional deficiency; toxicity; physical injury and shock; endocrine disorders, and myocarditides of viral, bacterial, and protozoal causation. Considerable overlap exists between each of the etiologic groups in the spectrum of pathologic alterations seen in the myocardium. These include various degenerative changes, myocyte necrosis, and inflammatory lesions. However, some diseases show rather characteristic myocardial alterations such as vacuolar degeneration in anthracycline cardiotoxicity, myofibrillar lysis in furazolidone cardiotoxicity, calcification in calcinosis of mice, glycogen accumulation in the glycogenoses, lipofuscinosis in cattle, fatty degeneration in erucic acid cardiotoxicity, myofiber disarray in hypertrophic cardiomyopathy, and lymphocytic inflammation with inclusion bodies in canine parvoviral myocarditis. The myocardial diseases represent the largest group in the spectrum of spontaneous cardiac diseases of animals. Pericardial and endocardial diseases and congential cardiac diseases are

  2. Augmented myocardial perfusion reserve after coronary angioplasty quantified by positron emission tomography with H2(15)O

    SciTech Connect

    Walsh, M.N.; Geltman, E.M.; Steele, R.L.; Kenzora, J.L.; Ludbrook, P.A.; Sobel, B.E.; Bergmann, S.R. )

    1990-01-01

    Effects of coronary angioplasty on myocardial flow reserve have been difficult to characterize noninvasively because conventional imaging techniques cannot quantitate blood flow in absolute terms. The effects of coronary angioplasty on myocardial perfusion and perfusion reserve were delineated with positron emission tomography and oxygen-15-labeled water (H2(15)O) in 13 patients before and after single vessel angioplasty. In 11 patients, angioplasty was successful (minimal cross-sectional area increased from 0.60 +/- 0.59 to 3.45 +/- 1.09 mm2, p less than 0.001). In these patients, regional H2(15)O radioactivity (the ratio of nutritional perfusion in regions distal to the stenosis compared with regions supplied by angiographically normal arteries) at rest before angioplasty was 55 +/- 22% of peak myocardial radioactivity and did not increase significantly afterward (70 +/- 16%, p = NS). However, after administration of intravenous dipyridamole, hyperemic perfusion in regions distal to a stenosis averaged only 39 +/- 18% of peak myocardial counts before angioplasty, but increased to 66 +/- 22% after angioplasty (p less than 0.02). Perfusion reserve in the two patients in whom angioplasty was angiographically unsuccessful showed no change. Quantitative estimates of perfusion in absolute rather than relative terms were obtained with positron emission tomographic data from seven of the patients with successful angioplasty. At rest, perfusion in regions distal to a stenosis was not different from the values in regions supplied by normal coronary arteries (1.54 +/- 0.54 compared with 1.46 +/- 0.38 ml/g per min, p = NS).

  3. The impact of supersaturation level for oral absorption of BCS class IIb drugs, dipyridamole and ketoconazole, using in vivo predictive dissolution system: Gastrointestinal Simulator (GIS).

    PubMed

    Tsume, Yasuhiro; Matsui, Kazuki; Searls, Amanda L; Takeuchi, Susumu; Amidon, Gregory E; Sun, Duxin; Amidon, Gordon L

    2017-05-01

    The development of formulations and the assessment of oral drug absorption for Biopharmaceutical Classification System (BCS) class IIb drugs is often a difficult issue due to the potential for supersaturation and precipitation in the gastrointestinal (GI) tract. The physiological environment in the GI tract largely influences in vivo drug dissolution rates of those drugs. Thus, those physiological factors should be incorporated into the in vitro system to better assess in vivo performance of BCS class IIb drugs. In order to predict oral bioperformance, an in vitro dissolution system with multiple compartments incorporating physiologically relevant factors would be expected to more accurately predict in vivo phenomena than a one-compartment dissolution system like USP Apparatus 2 because, for example, the pH change occurring in the human GI tract can be better replicated in a multi-compartmental platform. The Gastrointestinal Simulator (GIS) consists of three compartments, the gastric, duodenal and jejunal chambers, and is a practical in vitro dissolution apparatus to predict in vivo dissolution for oral dosage forms. This system can demonstrate supersaturation and precipitation and, therefore, has the potential to predict in vivo bioperformance of oral dosage forms where this phenomenon may occur. In this report, in vitro studies were performed with dipyridamole and ketoconazole to evaluate the precipitation rates and the relationship between the supersaturation levels and oral absorption of BCS class II weak base drugs. To evaluate the impact of observed supersaturation levels on oral absorption, a study utilizing the GIS in combination with mouse intestinal infusion was conducted. Supersaturation levels observed in the GIS enhanced dipyridamole and ketoconazole absorption in mouse, and a good correlation between their supersaturation levels and their concentration in plasma was observed. The GIS, therefore, appears to represent in vivo dissolution phenomena and

  4. An adult case of Kawasaki disease with multiplex coronary aneurysms and myocardial infarction: the role of transesophageal echocardiography.

    PubMed

    Habon, T; Toth, K; Keltai, M; Lengyel, M; Palik, I

    1998-07-01

    Kawasaki disease (mucocutaneous lymph node syndrome) is an acute inflammatory disease that primarily affects infants and young children. In spite of proper therapy, coronary aneurysms develop in 10 to 25% of cases. Adult diagnosis of coronary aneurysm, presumably caused by Kawasaki disease, is rare. A 37-year-old male patient with previous inferior wall myocardial infarction (MI) was admitted with an acute anterior wall MI. Coronary angiography, performed 2 weeks after successful thrombolytic therapy, showed right coronary artery occlusion and multiplex (left main, left anterior descending, left circumflex, right coronary artery) giant coronary aneurysms. Transthoracic echocardiography was unable to detect the aneurysms. Transesophageal echocardiography (TEE) visualized a large left main coronary aneurysm with an occlusive thrombus and measured low flow velocity (0.2 m/s) in the proximal left anterior descending artery. At 4 weeks control, TEE showed marked regression of the thrombus, and it was not detectable after 6 months of oral anticoagulation with acenocumarol (International Normalized Ratio: 3-3.5) and standard postinfarction therapy. After 2 years of follow-up, the patient has no symptoms, and myocardial ischemia could not be provoked by stress tests [treadmill, dipyridamole single-photon emission computed tomography (SPECT)]. We conclude that, for diagnosis and follow-up of adult Kawasaki disease, transesophageal echocardiography is indicated. The importance and efficacy of long-term anticoagulant treatment should be emphasized in this disease.

  5. Perioperative Assessment of Myocardial Deformation

    PubMed Central

    Duncan, Andra E.; Alfirevic, Andrej; Sessler, Daniel I.; Popovic, Zoran B.; Thomas, James D.

    2014-01-01

    Evaluation of left ventricular performance improves risk assessment and guides anesthetic decisions. However, the most common echocardiographic measure of myocardial function, the left ventricular ejection fraction (LVEF), has important limitations. LVEF is limited by subjective interpretation which reduces accuracy and reproducibility, and LVEF assesses global function without characterizing regional myocardial abnormalities. An alternative objective echocardiographic measure of myocardial function is thus needed. Myocardial deformation analysis, which performs quantitative assessment of global and regional myocardial function, may be useful for perioperative care of surgical patients. Myocardial deformation analysis evaluates left ventricular mechanics by quantifying strain and strain rate. Strain describes percent change in myocardial length in the longitudinal (from base to apex) and circumferential (encircling the short-axis of the ventricle) direction and change in thickness in the radial direction. Segmental strain describes regional myocardial function. Strain is a negative number when the ventricle shortens longitudinally or circumferentially and is positive with radial thickening. Reference values for normal longitudinal strain from a recent meta-analysis using transthoracic echocardiography are (mean ± SD) −19.7 ± 0.4%, while radial and circumferential strain are 47.3 ± 1.9 and −23.3 ± 0.7%, respectively. The speed of myocardial deformation is also important and is characterized by strain rate. Longitudinal systolic strain rate in healthy subjects averages −1.10 ± 0.16 sec−1. Assessment of myocardial deformation requires consideration of both strain (change in deformation), which correlates with LVEF, and strain rate (speed of deformation), which correlates with rate of rise of left ventricular pressure (dP/dt). Myocardial deformation analysis also evaluates ventricular relaxation, twist, and untwist, providing new and noninvasive methods to

  6. Poly(DL-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate): synthesis, characterization, micellization behavior in aqueous solutions, and encapsulation of the hydrophobic drug dipyridamole.

    PubMed

    Karanikolopoulos, Nikos; Zamurovic, Miljana; Pitsikalis, Marinos; Hadjichristidis, Nikos

    2010-02-08

    We synthesized a series of well-defined poly(dl-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate) (PDLLA-b-PDMAEMA) amphiphilic diblock copolymers by employing a three-step procedure: (a) ring-opening polymerization (ROP) of dl-lactide using n-decanol and stannous octoate, Sn(Oct)(2), as the initiating system, (b) reaction of the PDLLA hydroxyl end groups with bromoisobutyryl bromide, and (c) atom transfer radical polymerization, ATRP, of DMAEMA with the newly created bromoisobutyryl initiating site. The aggregation behavior of the prepared block copolymers was investigated by dynamic light scattering and zeta potential measurements at 25 degrees C in aqueous solutions of different pH values. The hydrophobic drug dipyridamole was efficiently incorporated into the copolymer aggregates in aqueous solutions of pH 7.40. High partition coefficient values were determined by fluorescence spectroscopy.

  7. Magnitude and time course of platelet inhibition with extended release dipyridamole with or without aspirin in healthy Japanese volunteers. The AGgrenox versus Aspirin Therapy Evaluation (AGATE-Japan).

    PubMed

    Serebruany, Victor L; Malinin, Alex I; Hanley, Dan F

    2008-01-01

    Randomized trials showed greater stroke prevention with extended release dipyridamole in combination with low dose aspirin than with either aspirin or dipyridamole alone. However, most studies with this formulation (Aggrenox) were carried out in Europe and North America. Considering potential inter-racial differences in drug response, we conducted a small randomized study in healthy Japanese volunteers to compare antiplatelet regimens with regard to the changes in the platelet biomarkers. Thirty healthy volunteers (18-40 years old, 15 male and 15 female) of Japanese descent were randomized to Aggrenox (n = 17) or aspirin 81 mg (n = 13 volunteers) for 30 days. Platelet function was assessed at baseline, and on days 15, and 30 by conventional aggregometry, whole blood flow cytometry, and cartridge-based analyzer. Both Aggrenox and aspirin provided sustained platelet inhibition at Day 15 and Day 30. Therapy with Aggrenox, however, was associated with more prominent and significant inhibition of collagen-induced aggregation (p = 0.08, Day 15), as well as prolongation of the closure time (p = 0.001, Day 30); diminished expression of platelet endothelial cell adhesion molecule-1 (PECAM-1) (p = 0.02, Day 30), glycoprotein IIb (GPIIb) antigen (p = 0.001 and 0.024 for Day 15 and Day 30), and GPIIb/IIIa activity by PAC-1 antibody (p = 0.014 and 0.03), CD62 (P-selectin) (p = 0.03 for Day 15 and Day 30), as well as inhibition of protease activated receptors (PAR-1) associated with intact WEDE-15 (p = 0.002 and 0.003) and SPAN-12 (p = 0.002 and 0.04) thrombin receptors when compared with aspirin. The magnitude and durability of platelet response after Aggrenox in healthy Japanese is similar to those effects observed in Caucasians and African-Americans. A larger study to assess drug efficacy and safety in the Japanese post-stroke patients is warranted.

  8. Measurements of myocardial flow vs. extraction of rubidium under varying physiological conditions

    SciTech Connect

    Budinger, T.F.; Yano, Y.; Moyer, B.R.; Twitchell, J.A.; Brennan, K.M.; Huesman, R.H.

    1984-01-01

    The relationship between myocardial rubidium extraction (E) and flow (F) are well described by the single capillary model E = (1-exp(-PS/F)) with a permeability surface product PS = 0.87 cc/min/gm. Some effects of alkalosis and acidosis have been reported. Here the authors investigate the effects of dipyridamole, norepinephrine-atropine, exsanguination, pacing, ouabain and calcium on extraction using Rb-82 PET and Rb-86 acute studies with microspheres in dogs. Thoracotomies were performed for left atrial microsphere infusion. Anesthesia was by N/sub 2/O and methoxyflurane. The degree of exsanguination, drug levels administered and pacing rates were sufficient to produce flow modifications. Extraction was calculated by dividing FE from Rb observations by F from microsphere data. These results of extraction vs. flow do not show a significant dependence on the method used for flow modification. There was less than a 20% change in FE after an infusion of 0.04 mg/kg ouabain over 5 minutes in 3 replicate studies each on 4 dogs. An important finding not previously explained in flow vs. extraction studies is the occurrence of extraction values greater than 1.0 which is possible only if the distribution opportunities of small cations are greater than that of microspheres. This is equivalent to the well known hematocrit effect in small channels.

  9. Acute myocardial infarction.

    PubMed

    Boersma, Eric; Mercado, Nestor; Poldermans, Don; Gardien, Martin; Vos, Jeroen; Simoons, Maarten L

    2003-03-08

    Acute myocardial infarction is a common disease with serious consequences in mortality, morbidity, and cost to the society. Coronary atherosclerosis plays a pivotal part as the underlying substrate in many patients. In addition, a new definition of myocardial infarction has recently been introduced that has major implications from the epidemiological, societal, and patient points of view. The advent of coronary-care units and the results of randomised clinical trials on reperfusion therapy, lytic or percutaneous coronary intervention, and chronic medical treatment with various pharmacological agents have substantially changed the therapeutic approach, decreased in-hospital mortality, and improved the long-term outlook in survivors of the acute phase. New treatments will continue to emerge, but the greatest challenge will be to effectively implement preventive actions in all high-risk individuals and to expand delivery of acute treatment in a timely fashion for all eligible patients.

  10. Myocardial gene therapy

    NASA Astrophysics Data System (ADS)

    Isner, Jeffrey M.

    2002-01-01

    Gene therapy is proving likely to be a viable alternative to conventional therapies in coronary artery disease and heart failure. Phase 1 clinical trials indicate high levels of safety and clinical benefits with gene therapy using angiogenic growth factors in myocardial ischaemia. Although gene therapy for heart failure is still at the pre-clinical stage, experimental data indicate that therapeutic angiogenesis using short-term gene expression may elicit functional improvement in affected individuals.

  11. Myocardial Tagging With SSFP

    PubMed Central

    Herzka, Daniel A.; Guttman, Michael A.; McVeigh, Elliot R.

    2007-01-01

    This work presents the first implementation of myocardial tagging with refocused steady-state free precession (SSFP) and magnetization preparation. The combination of myocardial tagging (a noninvasive method for quantitative measurement of regional and global cardiac function) with the high tissue signal-to-noise ratio (SNR) obtained with SSFP is shown to yield improvements in terms of the myocardium–tag contrast-to-noise ratio (CNR) and tag persistence when compared to the current standard fast gradient-echo (FGRE) tagging protocol. Myocardium–tag CNR and tag persistence were studied using numerical simulations as well as phantom and human experiments. Both quantities were found to decrease with increasing imaging flip angle (α) due to an increased tag decay rate and a decrease in myocardial steady-state signal. However, higher α yielded better blood–myocardium contrast, indicating that optimal α is dependent on the application: higher α for better blood–myocardium boundary visualization, and lower α for better tag persistence. SSFP tagging provided the same myocardium–tag CNR as FGRE tagging when acquired at four times the bandwidth and better tag– and blood–myocardium CNRs than FGRE tagging when acquired at equal or twice the receiver bandwidth (RBW). The increased acquisition efficiency of SSFP allowed decreases in breath-hold duration, or increases in temporal resolution, as compared to FGRE. PMID:12541254

  12. Optimally Repeatable Kinetic Model Variant for Myocardial Blood Flow Measurements with 82Rb PET

    PubMed Central

    deKemp, Robert A.; Renaud, Jennifer M.; Adler, Andy; Beanlands, Rob S. B.; Klein, Ran

    2017-01-01

    Purpose. Myocardial blood flow (MBF) quantification with 82Rb positron emission tomography (PET) is gaining clinical adoption, but improvements in precision are desired. This study aims to identify analysis variants producing the most repeatable MBF measures. Methods. 12 volunteers underwent same-day test-retest rest and dipyridamole stress imaging with dynamic 82Rb PET, from which MBF was quantified using 1-tissue-compartment kinetic model variants: (1) blood-pool versus uptake region sampled input function (Blood/Uptake-ROI), (2) dual spillover correction (SOC-On/Off), (3) right blood correction (RBC-On/Off), (4) arterial blood transit delay (Delay-On/Off), and (5) distribution volume (DV) constraint (Global/Regional-DV). Repeatability of MBF, stress/rest myocardial flow reserve (MFR), and stress/rest MBF difference (ΔMBF) was assessed using nonparametric reproducibility coefficients (RPCnp = 1.45 × interquartile range). Results. MBF using SOC-On, RVBC-Off, Blood-ROI, Global-DV, and Delay-Off was most repeatable for combined rest and stress: RPCnp = 0.21 mL/min/g (15.8%). Corresponding MFR and ΔMBF RPCnp were 0.42 (20.2%) and 0.24 mL/min/g (23.5%). MBF repeatability improved with SOC-On at stress (p < 0.001) and tended to improve with RBC-Off at both rest and stress (p < 0.08). DV and ROI did not significantly influence repeatability. The Delay-On model was overdetermined and did not reliably converge. Conclusion. MBF and MFR test-retest repeatability were the best with dual spillover correction, left atrium blood input function, and global DV. PMID:28293274

  13. Higher event rate in patients with known CAD despite a normal myocardial perfusion scan

    PubMed Central

    Fatima, Nosheen; Zaman, Unaiza; Zaman, Areeba; Balcoh, Dad J.; Rasheed, S Zahed

    2014-01-01

    Objective The negative predictive value of a normal single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is very high. However, prognostic implication of a normal SPECT MPI in patients with known coronary artery disease (CAD) is not clear. Objective of this study was to evaluate the cardiac event rate in patients with known CAD who had a normal stress SPECT MPI. Methods This prospective study accrued 428 consecutive patients with a history of CAD [revascularization or previous myocardial infarction (MI)] who had a normal stress (dynamic exercise or dipyridamole intervention) and rest Tc-99m-MIBI SPECT MPI. These patients were followed for 2-5 years (median: 3.1 years) for all-cause and cardiac mortality and non-fatal MI. Univariate and multivariate analyses were performed to identify predictors of outcome. Results During a follow-up period, all-cause mortality was found in 60 patients (14%) and 41 (10%) died of cardiac reasons. Non-fatal MI was found in 77 (18%) patients. Annualized cardiac mortality and non-fatal MI rates were 2% and 3.6% respectively. Smoking, congestive heart failure (CHF) and failure to achieve 85% age predicted heart rate were found to be predictors for all-cause and cardiac mortality. Diabetes, dyslipidemia, smoking and limited functional capacity (<7 METS) were found to be predictors for non-fatal MI. Conclusions Patients with known CAD had higher cardiac event rates despite a normal stress SPECT MPI. Diabetes, dyslipidemia, smoking and limited functional capacity were the predictors for fatal and non-fatal cardiac events. A cost effective but comprehensive surveillance strategy is warranted. PMID:25009792

  14. Perioperative myocardial infarction in patients undergoing myocardial revascularization surgery

    PubMed Central

    Pretto, Pericles; Martins, Gerez Fernandes; Biscaro, Andressa; Kruczan, Dany David; Jessen, Barbara

    2015-01-01

    Introduction Perioperative myocardial infarction adversely affects the prognosis of patients undergoing coronary artery bypass graft and its diagnosis was hampered by numerous difficulties, because the pathophysiology is different from the traditional instability atherosclerotic and the clinical difficulty to be characterized. Objective To identify the frequency of perioperative myocardial infarction and its outcome in patients undergoing coronary artery bypass graft. Methods Retrospective cohort study performed in a tertiary hospital specialized in cardiology, from May 01, 2011 to April 30, 2012, which included all records containing coronary artery bypass graft records. To confirm the diagnosis of perioperative myocardial infarction criteria, the Third Universal Definition of Myocardial Infarction was used. Results We analyzed 116 cases. Perioperative myocardial infarction was diagnosed in 28 patients (24.1%). Number of grafts and use and cardiopulmonary bypass time were associated with this diagnosis and the mean age was significantly higher in this group. The diagnostic criteria elevated troponin I, which was positive in 99.1% of cases regardless of diagnosis of perioperative myocardial infarction. No significant difference was found between length of hospital stay and intensive care unit in patients with and without this complication, however patients with perioperative myocardial infarction progressed with worse left ventricular function and more death cases. Conclusion The frequency of perioperative myocardial infarction found in this study was considered high and as a consequence the same observed average higher troponin I, more cases of worsening left ventricular function and death. PMID:25859867

  15. Impact of unexpected factors on quantitative myocardial perfusion and coronary flow reserve in young, asymptomatic volunteers.

    PubMed

    Sdringola, Stefano; Johnson, Nils P; Kirkeeide, Richard L; Cid, Emma; Gould, K Lance

    2011-04-01

    We sought to quantify ranges of normal myocardial perfusion and flow reserve in young, asymptomatic volunteers after systematic historical and laboratory screening for unexpected factors affecting coronary flow. Noninvasive cardiac positron emission tomography (PET) quantifies absolute flow and coronary flow reserve (CFR), thereby defining physiological severity of coronary artery disease for clinical studies or management. Defining "normal" coronary flow is a necessary prerequisite to its broad clinical application. Volunteers aged 20 to 40 years of age without cardiac disease or other conditions underwent rest-dipyridamole stress cardiac PET with absolute quantitative flow measurements using Rb-82 in paired studies at least 7 days apart for reproducibility. The presence of coronary calcium, detectable blood nicotine or caffeine, dyslipidemia, and an extended family history of early clinical atherosclerosis were objectively and systematically examined for grouping subjects as true normal or not normal. We enrolled 125 volunteers, 107 (86%) underwent 2 PET scans. Fifty-six (45%) were classified as true normal, whereas 69 (55%) were classified as not normal. True normals had higher high-density lipoprotein and less PET scan heterogeneity. Hemodynamic responses to dipyridamole stress were similar. Rest flow was the same in both groups (0.72 ± 0.17 ml/min/g vs. 0.69 ± 0.14 ml/min/g, p = 0.164). However, stress flow (2.89 ± 0.50 ml/min/g vs. 2.63 ± 0.61 ml/min/g, p = 0.005) and CFR (4.17 ± 0.80 vs. 3.91 ± 0.86, p = 0.047) were higher in true normals. Paired studies were performed a median of 22 days (interquartile range: 15 to 39) apart. Reproducibility was improved in the true normal group. One-half of young, asymptomatic volunteers from the community harbor unexpected factors that mildly but systematically reduce stress flow, CFR, and reproducibility. This study establishes normal ranges and reproducibility for flow and CFR as the basis for clinical

  16. Effect of power Doppler and digital subtraction techniques on the comparison of myocardial contrast echocardiography with SPECT.

    PubMed

    Haluska, B; Case, C; Short, L; Anderson, J; Marwick, T H

    2001-05-01

    To compare the accuracy and feasibility of harmonic power Doppler and digitally subtracted colour coded grey scale imaging for the assessment of perfusion defect severity by single photon emission computed tomography (SPECT) in an unselected group of patients. Cohort study. Regional cardiothoracic unit. 49 patients (mean (SD) age 61 (11) years; 27 women, 22 men) with known or suspected coronary artery disease were studied with simultaneous myocardial contrast echo (MCE) and SPECT after standard dipyridamole stress. Regional myocardial perfusion by SPECT, performed with (99m)Tc tetrafosmin, scored qualitatively and also quantitated as per cent maximum activity. Normal perfusion was identified by SPECT in 225 of 270 segments (83%). Contrast echo images were interpretable in 92% of patients. The proportion of normal MCE by grey scale, subtracted, and power Doppler techniques were respectively 76%, 74%, and 88% (p < 0.05) at > 80% of maximum counts, compared with 65%, 69%, and 61% at < 60% of maximum counts. For each technique, specificity was lowest in the lateral wall, although power Doppler was the least affected. Grey scale and subtraction techniques were least accurate in the septal wall, but power Doppler showed particular problems in the apex. On a per patient analysis, the sensitivity was 67%, 75%, and 83% for detection of coronary artery disease using grey scale, colour coded, and power Doppler, respectively, with a significant difference between power Doppler and grey scale only (p < 0.05). Specificity was also the highest for power Doppler, at 55%, but not significantly different from subtracted colour coded images. Myocardial contrast echo using harmonic power Doppler has greater accuracy than with grey scale imaging and digital subtraction. However, power Doppler appears to be less sensitive for mild perfusion defects.

  17. Myocardial revascularisation after acute myocardial infarction.

    PubMed

    Bana, A; Yadava, O P; Ghadiok, R; Selot, N

    1999-05-15

    One hundred and twenty-three patients had coronary artery bypass grafting (CABG) within 30 days of acute myocardial infarction (AMI) from May 1992 to November 1997. Commonest infarct was anterior transmural (61.8%) and commonest indication of surgery was post-infarct persistent or recurrent angina (69.1%). Ten patients were operated within 48 h and 36 between 48 h to 2 weeks of having MI. Out of these, nine patients were having infarct extension and cardiogenic shock at the time of surgery. Pre-operatively fourteen patients were on inotropes of which six also had intra-aortic balloon pump (IABP) support. All patients had complete revascularisation with 3.8+/-1.2 distal anastomoses per patient. By multivariate analysis, we found that independent predictors of post-operative morbidity [inotropes >48 h, use of IABP, ventilation >24 h, ICU stay >5 days] and complications [re-exploration, arrhythmias, pulmonary complications, wound infection, cerebrovascular accident (CVA)] were left ventricular ejection fraction (LVEF) <30%, Q-wave MI, surgery <48 h after AMI, presence of pre-operative cardiogenic shock and age >60 years (P < or = 0.01). Mortality at 30 days was 3.3%. LVEF <30%, Q-wave MI, surgery <48 h after AMI, presence of pre-operative cardiogenic shock and age >60 years were found to be independent predictors of 30 days mortality (P < or = 0.01). Ninety patients were followed up for a mean duration of 33 months (1 to 65 months). There were three late deaths and five patients developed recurrence of angina. To conclude, CABG can be carried out with low risk following AMI in stable patients for post-infarct angina. Patients who undergo urgent or emergent surgery and who have pre-operative cardiogenic shock, IABP, poor left ventricular functions, age >60 years and Q-wave MI are at increased risk.

  18. Diurnal variations in myocardial metabolism

    USDA-ARS?s Scientific Manuscript database

    The heart is challenged by a plethora of extracellular stimuli over the course of a normal day, each of which distinctly influences myocardial contractile function. It is therefore not surprising that myocardial metabolism also oscillates in a time-of-day dependent manner. What is becoming increasin...

  19. Noninvasive assessment of coronary stenoses by myocardial perfusion imaging during pharmacologic coronary vasodilation. VIII. Clinical feasibility of positron cardiac imaging without a cyclotron using generator-produced rubidium-82

    SciTech Connect

    Gould, K.L.; Goldstein, R.A.; Mullani, N.A.; Kirkeeide, R.L.; Wong, W.H.; Tewson, T.J.; Berridge, M.S.; Bolomey, L.A.; Hartz, R.K.; Smalling, R.W.

    1986-04-01

    The purpose of this study was to determine the clinical feasibility of diagnosing significant coronary artery disease by positron imaging of myocardial perfusion without a cyclotron, using generator-produced rubidium-82 (/sup 82/Rb). Fifty patients underwent positron emission tomography of the entire heart using a multislice positron camera and intravenous /sup 82/Rb or nitrogen-13 ammonia (/sup 13/NH/sub 3/) before and after intravenous dipyridamole combined with handgrip stress. Images were read by two observers blinded as to clinical or arteriographic data. Automated quantitative coronary arteriography was obtained for the arteriographic determination of coronary flow reserve, previously demonstrated to be a single integrated measure of stenosis severity accounting for all its geometric dimensions of length, absolute diameter, percent narrowing and asymmetry by quantitative analysis of cine films. Significant coronary artery disease was defined as an arteriographically determined coronary flow reserve of less than 3.0 based on all stenosis dimensions. Any single geometric measure of stenosis severity alone was an inadequate reference standard for comparison with perfusion images. Sensitivity of identifying patients with coronary artery disease having an arteriographically determined coronary flow reserve of less than 3.0 was 95% by positron imaging with a specificity of 100%. The single case that was missed, studied with /sup 13/NH/sub 3/, had a 43% diameter narrowing of a small ramus intermedius off the left coronary artery with no significant narrowing of the major coronary arteries. Positron emission tomography of myocardial perfusion before and after intravenous dipyridamole combined with handgrip stress utilizing generator-produced /sup 82/Rb provides sensitive and specific diagnosis of reduced coronary flow reserve due to coronary artery disease in humans.

  20. Influence of attenuation correction on transient left ventricular dilation in dual isotope myocardial perfusion imaging in patients with known or suspected coronary artery disease.

    PubMed

    Brodov, Yafim; Frenkel, Alex; Chouraqui, Pierre; Przewloka, Kinga; Rispler, Shmuel; Abadi, Sobhi; Keidar, Zohar

    2012-07-01

    The aim of this study was to assess the effect of attenuation correction (AC) on left ventricular (LV) volumes and LV transient ischemic dilatation (TID) during dual-isotope single-photon emission computer tomographic (SPECT) myocardial perfusion imaging (MPI). Ninety-six patients (mean age 58 ± 11 years, 15% women, 38 patients completed exercise and 58 dipyridamole pharmacologic stress tests) assessed for known or suspected coronary artery disease underwent dual-isotope thallium-201 rest and technetium-99m sestamibi stress SPECT MPI with computed tomography-based AC. The TID ratio was calculated separately for non-AC and AC SPECT MPI studies as the ratio of the LV endocardial volume at stress divided by LV endocardial volume at rest. The mean and range of the gated LV ejection fraction during exercise and pharmacologic stress was 54 ± 12% (29% to 80%) and 58 ± 12% (27% to 80%), respectively. In the exercise stress group, the same mean LV endocardial volumes in non-AC and AC stress (76.4 ± 30 and 76.5 ± 28) and rest (66.3 ± 26 and 66.4 ± 24) studies were found (p = 0.90). There was no statistical difference between the mean exercise TID ratio in non-AC and AC studies (1.27 vs 1.31, respectively, p = 0.10). The same mean LV endocardial volumes in non-AC and AC in pharmacologic stress (79.9 ± 42 and 80 ± 41) and rest (71.4 ± 41 and 72.3 ± 37), respectively, were found (p = 0.50). There was no statistical difference between the mean dipyridamole TID ratio in non-AC and AC studies (1.20 vs 1.17, respectively, p = 0.10). In conclusion, LV volumes and TID indexes obtained on SPECT MPI with exercise or pharmacologic stress using dipyridamole are not affected by AC. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. CT-based attenuation correction in (82)Rb-myocardial perfusion PET-CT: incidence of misalignment and effect on regional tracer distribution.

    PubMed

    Lautamäki, Riikka; Brown, Tracy L Y; Merrill, Jennifer; Bengel, Frank M

    2008-02-01

    Misalignment of low-dose-CT used for attenuation correction (AC) may cause artifacts in cardiac-PET-CT. The aim was to evaluate incidence and severity of misalignment and its quantitative effects on regional myocardial (82)Rb-distribution. Rest/dipyridamole (82)Rb-perfusion-PET-CT studies of 92 consecutive patients were analyzed for misalignment. Two different scanning protocols were employed: the first 57 patients had separate CTs for rest and stress PET. The following 35 patients had one CT at rest, used for AC of rest and stress PET. Misalignment was visually scored on a five-point scale (0 = no, 1 = minimal, 2 = mild, 3 = moderate, and 4 = severe). In five representative patients with normal perfusion and low probability of disease, 95 polarmaps were created by shifting CT vs PET prior to reconstruction of attenuation-corrected data sets using dedicated software (three dimensions of space; magnitude of shifts, 5, 10, 14 mm). PET/CT -misalignment was detected in 60% of rest and 67% of stress studies. Alignment for rest was better than that for stress (0.7 +/- 0.7 vs 1.0 +/- 0.9, P = 0.03). Comparison of the two protocols revealed no effect on the alignment of the stress study (1.0 +/- 0.9 vs 1.0 +/- 0.9, P = 0.9). Quantitatively, the largest individual effect of any artificial misalignment was a 25% reduction of relative (82)Rb uptake. With a shift of 1 cm, the largest effect in an individual was a 19% decrease. Anterior wall was most frequently influenced by misalignment, but changes of uptake also occurred in all other segments. Misalignment between CT and PET in cardiac-PET-CT influences regional tracer distribution in multiple segments. Repeated CT imaging after dipyridamole does not improve alignment. These results emphasize the need for strategies to improve coregistration in clinical imaging protocols.

  2. Bone regeneration in critical bone defects using three-dimensionally printed β-tricalcium phosphate/hydroxyapatite scaffolds is enhanced by coating scaffolds with either dipyridamole or BMP-2.

    PubMed

    Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L; Cronstein, Bruce N

    2017-02-01

    Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3D) printing technology we have created custom 3D scaffolds of hydroxyapatite (HA)/beta-tri-calcium phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. Nearly 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3D Robocasting system, and sintered at 1100°C for 4 h. Scaffolds were coated with BMP-2 (200 ng mL(-1) ), dypiridamole 100 µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3 mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. Micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP-dipyridamole and HA/β-TCP-BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4, and 8 weeks (n = 5 per group; p ≤ 0.05, p ≤ 0.05, and p ≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. Coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 366-375, 2017.

  3. Prevention of myocardial infarction.

    PubMed

    Adams, M R

    2002-12-01

    Despite the rapid advances that have been made in the treatment of coronary artery disease, myocardial infarction remains the major cause of death in the developed world and a growing problem for developing countries. To address this growing problem, a strategy aimed at prevention of events in high-risk individuals is required. This involves assessment of cardiovascular risk followed by risk reduction. At present there is no perfect technique available for risk prediction, although computed tomography and magnetic resonance imaging scanning, along with serum markers of inflammation, offer the greatest potential. The applicability of these techniques at present is also limited by cost and accessibility. Risk reduction is possible through lifestyle changes and drug therapy, and effective risk assessment is essential in selecting those most likely to benefit from these interventions.

  4. Significance of both negative T waves and stress-induced normalization of the repolarization phase in infarcted patients: a positron-emission-tomography assessment of regulation of myocardial blood flow and viability of myocardium.

    PubMed

    Giorgetti, A; Sambuceti, G; Neglia, D; Sorace, O; Salvadori, P A; Parodi, O

    2001-05-01

    The clinical correlation of stress-induced normalization of previously negative T waves (NNTW) to regulation of regional myocardial blood flow (MBF) and tissue viability is still being debated. To clarify its meaning. We studied 25 patients, who had previously suffered anterior myocardial infarction and for whom negative T waves were recorded on baseline electrocardiographic precordial leads, by means of positron emission tomography. We obtained MBF in the infarcted myocardial regions under resting conditions for all patients, during infusion of dipyridamole (17 patients) and dobutamine (20 patients), using [13N]-ammonia as a flow tracer. During stress tests, 13 patients exhibited NNTW (group 1) whereas the remaining 12 presented persistent negative T waves (group 2). NNTW was observed in 18 stress studies (for 10 and eight patients during administration of dobutamine and dipyridamole, respectively) whereas persistent negative T waves occurred 19 times (for 10 patients during infusion of dobutamine and nine patients during administration of dipyridamole). A complete concordance of the modifications of the repolarization phase was observed for patients who were subjected both to dipyridamole and to dobutamine studies. Furthermore, we assessed viability of myocardium in 20 of 25 patients using [18F]-fluorodeoxyglucose. For the remaining five patients not subjected to metabolic imaging, a coronary reserve of 1.65 was considered a cut-off of viability. Resting MBF for patients in groups 1 and 2 were similar (0.53 +/- 0.20 versus 0.47 +/- 0.17 ml/min per g, respectively, NS) whereas during pharmacological stress, MBF of patients in group 1 was significantly higher than that for patients in group 2 (0.99 +/- 0.41 versus 0.56 +/- 0.26 ml/min per g, respectively, P < 0.0001). Coronary vasodilating capability, expressed as stress/resting MBF ratio, turned out to be 1.88 +/- 0.49 and 1.16 +/- 0.37 for patients in groups 1 and 2, respectively (P < 0.0001). We observed no

  5. Positron emission tomography for the assessment of myocardial viability: an evidence-based analysis.

    PubMed

    2010-01-01

    myocardial viability. Intravenous contrast agents, which are high molecular weight inert gas microbubbles that act like red blood cells in the vascular space, can be used during echocardiography to assess myocardial viability. These agents allow for the assessment of myocardial blood flow (perfusion) and contractile function (as described above), as well as the simultaneous assessment of perfusion to make it possible to distinguish between stunned and hibernating myocardium. SPECT: SPECT can be performed using thallium-201 (Tl-201), a potassium analogue, or technetium-99 m labelled tracers. When Tl-201 is injected intravenously into a patient, it is taken up by the myocardial cells through regional perfusion, and Tl-201 is retained in the cell due to sodium/potassium ATPase pumps in the myocyte membrane. The stress-redistribution-reinjection protocol involves three sets of images. The first two image sets (taken immediately after stress and then three to four hours after stress) identify perfusion defects that may represent scar tissue or viable tissue that is severely hypoperfused. The third set of images is taken a few minutes after the re-injection of Tl-201 and after the second set of images is completed. These re-injection images identify viable tissue if the defects exhibit significant fill-in (> 10% increase in tracer uptake) on the re-injection images. The other common Tl-201 viability imaging protocol, rest-redistribution, involves SPECT imaging performed at rest five minutes after Tl-201 is injected and again three to four hours later. Viable tissue is identified if the delayed images exhibit significant fill-in of defects identified in the initial scans (> 10% increase in uptake) or if defects are fixed but the tracer activity is greater than 50%. There are two technetium-99 m tracers: sestamibi (MIBI) and tetrofosmin. The uptake and retention of these tracers is dependent on regional perfusion and the integrity of cellular membranes. Viability is assessed using

  6. Death Due to Myocardial Bridging.

    PubMed

    Ural, M Numan; Eren, Filiz; Inanir, Nursel Türkmen; Eren, Bülent; Vojtisek, Tomas; Gürses, Murat Serdar

    2015-06-01

    Myocardial bridging is a congenital coronary pathology described as a segment of coronary artery which courses through the myocardial wall beneath the muscle bridge. Although the myocardial bridging prognosis is benign, have been also reported sudden death in medical literature. ¬A 30-year-old married woman was found dead at her home. After local prosecutors' investigation the death was declared as suspicious and forensic autopsy was obliged. The left anterior descending coronary artery was detected embedded deeply in the myocardium 2 cm from its coronary ostial origin. There were no other pathology to explain death. We analyzed sudden death case occurred because of myocardial bridging and the pathophysiological mechanisms in the light of medico-legal literature.

  7. [Comparison of various parameters for determining an index of myocardial perfusion reserve in detecting coronary stenosis with cardiovascular magnetic resonance tomography].

    PubMed

    al-Saadi, N; Gross, M; Bornstedt, A; Schnackenburg, B; Klein, C; Fleck, E; Nagel, E

    2001-11-01

    For the assessment of myocardial perfusion with cardiac magnetic resonance imaging, different semiquantitative parameters of the first pass signal intensity time curves can be calculated and myocardial perfusion reserve indices can be determined. In this study we evaluated the feasibility of different perfusion parameters and their perfusion reserve indices for the detection of significant coronary artery stenosis. The signal intensity time curves of the first pass of a gadolinium-DTPA bolus injected via a central vein catheter before and after dipyridamole infusion were investigated in 15 patients with single vessel (stenosis > or = 75% area reduction) and five patients without significant coronary artery disease. For the distinction of ischemic and nonischemic myocardial segments, semiquantitative parameters, such as maximal signal intensity, contrast appearance time, time to maximal signal intensity and the steepness of the signal intensity curve's upslope determined by a linear fit, were assessed after correction for the input function. For each parameter a myocardial perfusion reserve index was calculated and cut off values for the detection of significant coronary stenosis were defined. The diagnostic accuracy of each parameter was then examined prospectively in 36 patients with coronary artery disease and compared with coronary angiography. Where as a distinction of ischemic and normal myocardium was possible with myocardial perfusion reserve indices, semiquantitative parameters at rest or after vasodilation alone did not allow such a distinction. The perfusion reserve index calculated from the upslope showed the most significant difference between ischemic and nonischemic myocardial segments (1.19 +/- 0.4 and 2.38 +/- 0.45, p < 0.001) followed by maximum signal intensity, time to maximum signal intensity and contrast apperance time. Sensitivity, specificity and diagnostic accuracy was 87, 82 and 85% for the detection of hypoperfusion induced by significant

  8. The declining frequency of inducible myocardial ischemia during stress echocardiography over 27 consecutive years (1983-2009).

    PubMed

    Carpeggiani, Clara; Landi, Patrizia; Michelassi, Claudio; Sicari, Rosa; Picano, Eugenio

    2016-12-01

    Previous studies have suggested a decline in positivity of stress cardiac imaging, suggesting the need for developing better strategies for test selection to achieve acceptable cost-effectiveness balance. The aim of this retrospective study was to assess the rate of positivity of stress echocardiography (SE) over 27 consecutive years. We assessed the rate of SE positivity in 2007 patients without previous myocardial infarction or coronary revascularization who performed SE in a tertiary care referral center from 1983 to 2009. SE was performed with dipyridamole (1427), dobutamine (136) or exercise (444). There was a progressive decline over time in the rate of SE positivity from 42% (1983-1991) to 22% (2001-2009), with a relative increase of patients with low pre-test probability of disease (from 5% to 27%). The percentage of patients studied with SE under anti-ischemic therapy increased markedly (from 8% in the first to 61% in the last nine years). Over 27 consecutive years, we observed a steady decline in SE positivity rate (with >5-fold increase of low probability patients), with almost 8-fold increase in anti-ischemic therapy at testing. We probably need refined criteria of referral for testing and/or better ways to titrate the negative response beyond wall motion abnormalities during SE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson.

    PubMed

    Noel, Cory V; Krishnamurthy, Ramkumar; Moffett, Brady; Krishnamurthy, Rajesh

    2017-03-01

    Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement

  10. Magnetic resonance imaging (MRI) for the assessment of myocardial viability: an evidence-based analysis.

    PubMed

    2010-01-01

    diagnostic accuracy of echocardiographic assessment of myocardial viability. Intravenous contrast agents, which are high molecular weight inert gas microbubbles that act like red blood cells in the vascular space, can be used during echocardiography to assess myocardial viability. These agents allow for the assessment of myocardial blood flow (perfusion) and contractile function (as described above), as well as the simultaneous assessment of perfusion to make it possible to distinguish between stunned and hibernating myocardium. SPECT: SPECT can be performed using thallium-201 (Tl-201), a potassium analogue, or technetium-99 m labelled tracers. When Tl-201 is injected intravenously into a patient, it is taken up by the myocardial cells through regional perfusion, and Tl-201 is retained in the cell due to sodium/potassium ATPase pumps in the myocyte membrane. The stress-redistribution-reinjection protocol involves three sets of images. The first two image sets (taken immediately after stress and then three to four hours after stress) identify perfusion defects that may represent scar tissue or viable tissue that is severely hypoperfused. The third set of images is taken a few minutes after the re-injection of Tl-201 and after the second set of images is completed. These re-injection images identify viable tissue if the defects exhibit significant fill-in (> 10% increase in tracer uptake) on the re-injection images. The other common Tl-201 viability imaging protocol, rest-redistribution, involves SPECT imaging performed at rest five minutes after Tl-201 is injected and again three to four hours later. Viable tissue is identified if the delayed images exhibit significant fill-in of defects identified in the initial scans (> 10% increase in uptake) or if defects are fixed but the tracer activity is greater than 50%. There are two technetium-99 m tracers: sestamibi (MIBI) and tetrofosmin. The uptake and retention of these tracers is dependent on regional perfusion and the

  11. Wave Propagation of Myocardial Stretch: Correlation with Myocardial Stiffness

    PubMed Central

    Pislaru, Cristina; Pellikka, Patricia A.; Pislaru, Sorin V.

    2015-01-01

    The mechanism of flow propagation during diastole in the left ventricle (LV) has been well described. Little is known about the associated waves propagating along the heart wall s. These waves may have a mechanism similar to pulse wave propagation in arteries. The major goal of the study was to evaluate the effect of myocardial stiffness and preload on this wave transmission. Methods Longitudinal late diastolic deformation and wave speed (Vp) of myocardial stretch in the anterior LV wall were measured using sonomicrometry in sixteen pigs. Animals with normal and altered myocardial stiffness (acute myocardial infarction) were studied with and without preload alterations. Elastic modulus estimated from Vp (EVP; Moens-Korteweg equation) was compared to incremental elastic modulus obtained from exponential end -diastolic stress-strain relation (ESS). Myocardial distensibility and α-and β-coefficients of stress-strain relations were calculated. Results Vp was higher at reperfusion compared to baseline (2.6±1.3 m/s vs. 1.3±0.4 m/s; p=0.005) and best correlated with ESS (r 2=0.80, p<0.0001), β-coefficient (r2=0.78, p<0.0001), distensibility (r2=0.47, p=0.005), and wall thickness/diameter ratio (r2=0.42, p=0.009). Elastic moduli (EVP and ESS) were strongly correlated (r2=0.83, p<0.0001). Increasing preload increased Vp and EVP and decreased distensibility. At multivariate analysis, ESS, wall thickness, and end-diastolic and systolic LV pressures were independent predictors of Vp (r2model=0.83, p<0.0001). Conclusions The main determinants of wave propagation of longitudinal myocardial stretch were myocardial stiffness and LV geometry and pressure. This local wave speed could potentially be measured noninvasively by echocardiography. PMID:25193091

  12. Wave propagation of myocardial stretch: correlation with myocardial stiffness.

    PubMed

    Pislaru, Cristina; Pellikka, Patricia A; Pislaru, Sorin V

    2014-01-01

    The mechanism of flow propagation during diastole in the left ventricle (LV) has been well described. Little is known about the associated waves propagating along the heart walls. These waves may have a mechanism similar to pulse wave propagation in arteries. The major goal of the study was to evaluate the effect of myocardial stiffness and preload on this wave transmission. Longitudinal late diastolic deformation and wave speed (Vp) of myocardial stretch in the anterior LV wall were measured using sonomicrometry in 16 pigs. Animals with normal and altered myocardial stiffness (acute myocardial infarction) were studied with and without preload alterations. Elastic modulus estimated from Vp (E VP; Moens-Korteweg equation) was compared to incremental elastic modulus obtained from exponential end-diastolic stress-strain relation (E SS). Myocardial distensibility and α- and β-coefficients of stress-strain relations were calculated. Vp was higher at reperfusion compared to baseline (2.6 ± 1.3 vs. 1.3 ± 0.4 m/s; p = 0.005) and best correlated with E SS (r2 = 0.80, p < 0.0001), β-coefficient (r2 = 0.78, p < 0.0001), distensibility (r2 = 0.47, p = 0.005), and wall thickness/diameter ratio (r2 = 0.42, p = 0.009). Elastic moduli (E VP and E SS) were strongly correlated (r2 = 0.83, p < 0.0001). Increasing preload increased Vp and E VP and decreased distensibility. At multivariate analysis, E SS, wall thickness, and end-diastolic and systolic LV pressures were independent predictors of Vp (r2 model = 0.83, p < 0.0001). In conclusion, the main determinants of wave propagation of longitudinal myocardial stretch were myocardial stiffness and LV geometry and pressure. This local wave speed could potentially be measured noninvasively by echocardiography.

  13. [Fatty acid metabolism in patients with idiopathic dilated cardiomyopathy: characteristics and prognostic implications].

    PubMed

    Narita, M; Kurihara, T

    1995-05-01

    The characteristics of myocardial fatty acid metabolism in patients with idiopathic dilated cardiomyopathy (DCM) were investigated by myocardial imaging with beta-methyl-p-[123I]iodophenyl-pentadecanoic acid (BMIPP) in 16 patients with DCM, 8 patients with hypertensive heart failure (HHF), and 11 normal subjects. Rest myocardial imaging with BMIPP and 201Tl was performed on another day. The index of myocardial BMIPP uptake, or uptake ratio, was calculated from the percentage uptakes of BMIPP and 201Tl. The index of inhomogeneity of intramyocardial isotope distribution was calculated as the coefficient of variation of BMIPP and 201Tl. The uptake ratio was significantly lower in DCM and HHF patients than in normal subjects (p < 0.01). Uptake ratio correlated well with fractional shortening (r = 0.76, p < 0.01), and left ventricular ejection fraction (r = 0.58, p < 0.01). Although uptake ratio was not different between DCM and HHF patients, defects in BMIPP imaging appeared more frequently in DCM (69%) than in HHF (38%) patients. Furthermore, the extent of the defect in BMIPP imaging in DCM patients was larger than that in 201Tl imaging (p < 0.05), but in HHF patients the extent of the defects in both methods was similar. The coefficient of variation of BMIPP in DCM patients was greater than those in HHF patients and in normal subjects, but those of 201Tl were not different between the three groups. The coefficient of variation of BMIPP in DCM patients correlated well with serum norepinephrine level (r = 0.57, p < 0.01) and atrial natriuretic peptide (r = 0.77, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Optimization of myocardial function.

    PubMed

    Alpert, N R; Mulieri, L A; Hasenfuss, G; Holubarsch, C

    1993-01-01

    Under normal conditions the cardiac output is designed to meet the metabolic needs of the organism. Thus, the demands imposed on the heart muscle can range from low values at rest to an order of magnitude greater values during exercise. The heart uses a number of strategies to meet the short- and long-term changes in demand. These strategies are of general biological interest and employ similar mechanisms to those responsible for the differences in muscle performance seen between muscle from various species and diverse muscle types within a given animal. This review deals with the heart's utilization of these strategies to meet a broad range of requirements. Tortoise (TM) and rat soleus (RS) muscles are slow, have high economy and develop low power. In contrast (FM) and rat extensor digitorum longus (REDL) are fast, have low economy and have a high power output. These differences are explainable in terms of the characteristics of the myosin head cross-bridge cycle (Cross-bridge tension-time integral: FM/FT = 0.024; REDL/RS = 0.16. Myosin ATPase activity: FM/TM = 15; RDEL/RS = 2.3) and excitation contraction coupling system (time to peak tension: FM/TM = 0.2; REDL/RS = 0.4). Heart muscle employs similar strategies (cross-bridge cycle; excitation contraction coupling) to meet short (catecholamine) and long (hypertrophy secondary to pressure overload or thyrotoxicosis) term changes in demand. In the presence of catecholamine power is increased while economy is decreased. This difference between control (C) and isoproterenol treated hearts (I) is explainable in terms of the contractile and excitation contraction coupling systems (Cross-bridge tension-time integral: I/C = 0.4. Tension independent heat: I/C = 2.0. Tension independent heat rate: I/C = 2.5). A persistent increase in the demand on the heart results in myocardial hypertrophy that is associated with intracellular reorganization. Hyperthyroidism (T) and pressure overload (PO) were used to produce myocardial

  15. Rat myocardial protein degradation.

    PubMed

    Steer, J H; Hopkins, B E

    1981-07-01

    1. Myocardial protein degradation rates were determined by following tyrosine release from rat isolated left hemi-atria in vitro. 2. After two 20 min preincubations the rate of tyrosine release from hemi-atria was constant for 4 h. 3. Skeletal muscle protein degradation was determined by following tyrosine release from rat isolated hemi-diaphragm (Fulks, Li & Goldberg, 1975). 4. Insulin (10(-7) M) inhibited tyrosine release from hemi-atria and hemi-diaphragm to a similar extent. A 48 h fast increased tyrosine release rate from hemi-diaphragm and decreased tyrosine release rate from hemi-atria. Hemi-diaphragm tyrosine release was inhibited by 15 mmol/l D-glucose but a variety of concentrations of D-glucose (0, 5, 15 mmol/l) had no effect on tyrosine release from hemi-atria. Five times the normal plasma levels of the branched-chain amino acids leucine, isoleucine and valine had no effect on tyrosine release from either hemi-atria or hemi-diaphragm.

  16. Myocardial complications of immunisations.

    PubMed

    Helle, E P; Koskenvuo, K; Heikkilä, J; Pikkarainen, J; Weckström, P

    1978-10-01

    Immunisation may induce myocardial complications. In this pilot study clinical, electrocardiographic, chemical and immunological findings have been studied during a six weeks' follow-up after routine immunisation (mumps, polio, tetanus, smallpox, diphtheria and type A meningococcal disease) among 234 Finnish conscripts at the beginning of their military service. Serial pattern of ECG changes suggestive of myocarditis was recorded in eight of the 234 conscripts one to two weeks after vaccination against smallpox and diphtheria. Changes were mainly minor ST segment elevations and T wave inversions and usually they disappeared in a few weeks. The ECG positives more often had a history of atopy, and their mean body temperatures and heart rates after the vaccinations were higher than among the other subjects (p less than 0.01). However, clinical myocarditis was never noted, nor were immunological or enzymological changes different among the ECG positives. Thus in 3% of the study population, evidence of postvaccinal myocarditis was noted, based on serial ECG patterns, but without any other evidence of cardiac disease.

  17. Myocardial mechanics in cardiomyopathies.

    PubMed

    Modesto, Karen; Sengupta, Partho P

    2014-01-01

    Cardiomyopathies are a heterogeneous group of diseases that can be phenotypically recognized by specific patterns of ventricular morphology and function. The authors summarize recent clinical observations that mechanistically link the multidirectional components of left ventricular (LV) deformation with morphological phenotypes of cardiomyopathies for offering key insights into the transmural heterogeneity of myocardial function. Subendocardial dysfunction predominantly alters LV longitudinal shortening, lengthening and suction performance and contributes to the phenotypic patterns of heart failure (HF) with preserved ejection fraction (EF) seen with hypertrophic and restrictive patterns of cardiomyopathy. On the other hand, a more progressive transmural disease results in reduction of LV circumferential and twist mechanics leading to the phenotypic pattern of dilated cardiomyopathy and the clinical syndrome of HF with reduced (EF). A proper characterization of LV transmural mechanics, energetics, and space-time distributions of pressure and shear stress may allow recognition of early functional changes that can forecast progression or reversal of LV remodeling. Furthermore, the interactions between LV muscle and fluid mechanics hold the promise for offering newer mechanistic insights and tracking impact of novel therapies.

  18. CAD of myocardial perfusion

    NASA Astrophysics Data System (ADS)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2007-03-01

    Our purpose is in the automated evaluation of the physiological relevance of lesions in coronary angiograms. We aim to extract as much as possible quantitative information about the physiological condition of the heart from standard angiographic image sequences. Coronary angiography is still the gold standard for evaluating and diagnosing coronary abnormalities as it is able to locate precisely the coronary artery lesions. The dimensions of the stenosis can be assessed nowadays successfully with image processing based Quantitative Coronary Angiography (QCA) techniques. Our purpose is to assess the clinical relevance of the pertinent stenosis. We therefore analyze the myocardial perfusion as revealed in standard angiographic image sequences. In a Region-of-Interest (ROI) on the angiogram (without an overlaying major blood vessel) the contrast is measured as a function of time (the so-called time-density curve). The required hyperemic state of exercise is induced artificially by the injection of a vasodilator drug e.g. papaverine. In order to minimize motion artifacts we select based on the recorded ECG signal end-diastolic images in both a basal and a hyperemic run in the same projection to position the ROI. We present the development of the algorithms together with results of a small study of 20 patients which have been catheterized following the standard protocol.

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

    SciTech Connect

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

    1988-08-01

    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).

  20. Prognostic value of myocardial ischemia and necrosis in depressed left ventricular function: a multicenter stress cardiac magnetic resonance registry.

    PubMed

    Husser, Oliver; Monmeneu, Jose V; Bonanad, Clara; Lopez-Lereu, Maria P; Nuñez, Julio; Bosch, Maria J; Garcia, Carlos; Sanchis, Juan; Chorro, Francisco J; Bodi, Vicente

    2014-09-01

    The incremental prognostic value of inducible myocardial ischemia over necrosis derived by stress cardiac magnetic resonance in depressed left ventricular function is unknown. We determined the prognostic value of necrosis and ischemia in patients with depressed left ventricular function referred for dipyridamole stress perfusion magnetic resonance. In a multicenter registry using stress magnetic resonance, the presence (≥ 2 segments) of late enhancement and perfusion defects and their association with major events (cardiac death and nonfatal infarction) was determined. In 391 patients, perfusion defect or late enhancement were present in 224 (57%) and 237 (61%). During follow-up (median, 96 weeks), 47 major events (12%) occurred: 25 cardiac deaths and 22 myocardial infarctions. Patients with major events displayed a larger extent of perfusion defects (6 segments vs 3 segments; P <.001) but not late enhancement (5 segments vs 3 segments; P =.1). Major event rate was significantly higher in the presence of perfusion defects (17% vs 5%; P =.0005) but not of late enhancement (14% vs 9%; P =.1). Patients were categorized into 4 groups: absence of perfusion defect and absence of late enhancement (n = 124), presence of late enhancement and absence of perfusion defect (n = 43), presence of perfusion defect and presence of late enhancement (n = 195), absence of late enhancement and presence of perfusion defect (n = 29). Event rate was 5%, 7%, 16%, and 24%, respectively (P for trend = .003). In a multivariate regression model, only perfusion defect (hazard ratio = 2.86; 95% confidence interval, 1.37-5.95]; P = .002) but not late enhancement (hazard ratio = 1.70; 95% confidence interval, 0.90-3.22; P =.105) predicted events. In depressed left ventricular function, the presence of inducible ischemia is the strongest predictor of major events. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  1. Effect of hypoxia on thallium kinetics in cultured chick myocardial cells

    SciTech Connect

    Friedman, B.J.; Beihn, R.; Friedman, J.P.

    1987-09-01

    To assess the effect of hypoxia on cellular thallium-201 (/sup 201/Tl) uptake and washout independent of coronary flow, we studied thallium kinetics during normoxia and hypoxia in cultured chick ventricular cells. Monolayers of contracting ventricular cells grown on coverslips were placed in a chamber and perfused to asymptote with media containing /sup 201/Tl. Perfusates were equilibrated with 5% CO/sub 2/-95% air or 5% CO/sub 2/-95% nitrogen for normoxia and hypoxia, respectively. Washout thallium kinetics were then observed during perfusion with unlabeled media. Twenty paired experiments were performed, randomly alternating the sequence of normoxia and hypoxia. Pharmacokinetics for thallium were determined by computer using standard formulae. Thallium uptake and washout were best described by assuming that intracellular thallium was contained within a single compartment. Cellular thallium uptake, as well as transfer rate constants for thallium uptake and for thallium washout during normoxia and hypoxia, were compared using paired t-tests. During normoxia and hypoxia, respectively, thallium uptake was 22 +/- 7% and 19 +/- 7% of asymptote (p less than 0.01); the compartmental rate constant for uptake by the cell was 0.16 +/- 0.07 min-1 and 0.15 +/- 0.06 min-1 (N.S.); and the transfer rate constant for washout from the cell was 0.26 +/- 0.06 min-1 and 0.23 +/- 0.05 min-1 (p less than 0.01). We conclude that there was a small (14%) decrease in thallium uptake during hypoxia. The rate of thallium uptake and washout was slightly less during hypoxia, although only the rate of washout was significantly less. These data show that cellular accumulation of thallium and the rate of washout of thallium were minimally decreased by hypoxia independent of blood flow.

  2. Myocardial perfusion imaging for detection of silent myocardial ischemia

    SciTech Connect

    Beller, G.A.

    1988-04-21

    Despite the widespread use of the exercise stress test in diagnosing asymptomatic myocardial ischemia, exercise radionuclide imaging remains useful for detecting silent ischemia in numerous patient populations, including those who are totally asymptomatic, those who have chronic stable angina, those who have recovered from an episode of unstable angina or an uncomplicated myocardial infarction, and those who have undergone angioplasty or received thrombolytic therapy. Studies show that thallium scintigraphy is more sensitive than exercise electrocardiography in detecting ischemia, i.e., in part, because perfusion defects occur more frequently than ST depression and before angina in the ischemic cascade. Thallium-201 scintigraphy can be performed to differentiate a true- from a false-positive exercise electrocardiographic test in patients with exercise-induced ST depression and no angina. The development of technetium-labeled isonitriles may improve the accuracy of myocardial perfusion imaging. 11 references.

  3. MYOCARDIAL AKT: THE OMNIPRESENT NEXUS

    PubMed Central

    Sussman, Mark A.; Völkers, Mirko; Fischer, Kimberlee; Bailey, Brandi; Cottage, Christopher T.; Din, Shabana; Gude, Natalie; Avitabile, Daniele; Alvarez, Roberto; Sundararaman, Balaji; Quijada, Pearl; Mason, Matt; Konstandin, Mathias H.; Malhowski, Amy; Cheng, Zhaokang; Khan, Mohsin; McGregor, Michael

    2013-01-01

    One of the greatest examples of integrated signal transduction is revealed by examination of effects mediated by AKT kinase in myocardial biology. Positioned at the intersection of multiple afferent and efferent signals, AKT exemplifies a molecular sensing node that coordinates dynamic responses of the cell in literally every aspect of biological responses. The balanced and nuanced nature of homeostatic signaling is particularly essential within the myocardial context, where regulation of survival, energy production, contractility, and response to pathological stress all flow through the nexus of AKT activation or repression. Equally important, the loss of regulated AKT activity is primarily the cause or consequence of pathological conditions leading to remodeling of the heart and eventual decompensation. This review presents an overview compendium of the complex world of myocardial AKT biology gleaned from more than a decade of research. Summarization of the widespread influence that AKT exerts upon myocardial responses leaves no doubt that the participation of AKT in molecular signaling will need to be reckoned with as a seemingly omnipresent regulator of myocardial molecular biological responses. PMID:21742795

  4. Diurnal variations in myocardial metabolism.

    PubMed

    Bray, Molly S; Young, Martin E

    2008-07-15

    The heart is challenged by a plethora of extracellular stimuli over the course of a normal day, each of which distinctly influences myocardial contractile function. It is therefore not surprising that myocardial metabolism also oscillates in a time-of-day dependent manner. What is becoming increasingly apparent is that the heart exhibits diurnal variations in its intrinsic properties, including responsiveness to extracellular stimuli. This article summarizes our current knowledge regarding the mechanism(s) mediating diurnal variations in myocardial metabolism. Particular attention is focused towards the intramyocardial circadian clock, a cell autonomous molecular mechanism that appears to regulate myocardial metabolism both directly (e.g. triglyceride and glycogen metabolism) and indirectly (through modulation of the responsiveness of the myocardium to workload, insulin, and fatty acids). In doing so, the circadian clock within the cardiomyocyte allows the heart to anticipate environmental stimuli (such as changes in workload, feeding status) prior to their onset. This synchronization between the myocardium and its environment is enhanced by regular feeding schedules. Conversely, loss of synchronization may occur through disruption of the circadian clock and/or diurnal variations in neurohumoral factors (as observed during diabetes mellitus). Here, we discuss the possibility that loss of synchronization between the heart and its environment predisposes the heart to metabolic maladaptation and subsequent myocardial contractile dysfunction.

  5. Myocardial perfusion SPECT 2015 in Germany. Results of the 7(th) survey.

    PubMed

    Lindner, Oliver; Burchert, Wolfgang; Schäfer, Wolfgang; Hacker, Marcus

    2017-02-14

    The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1 % [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring.

  6. Effects of long‐term treatment with carvedilol on myocardial blood flow in idiopathic dilated cardiomyopathy

    PubMed Central

    Neglia, Danilo; De Maria, Renata; Masi, Stefano; Gallopin, Michela; Pisani, Patrizia; Pardini, Silvia; Gavazzi, Antonello; L'Abbate, Antonio; Parodi, Oberdan

    2007-01-01

    Objective To assess whether chronic treatment with carvedilol can increase myocardial blood flow (MBF) and MBF reserve in idiopathic dilated cardiomyopathy (IDC). Study design In a double‐blind, placebo‐controlled trial, 16 consecutive patients with IDC were randomised to treatment with either carvedilol up to 25 mg twice a day (n = 8, 7 men, mean (SD) age 60 (9) years, mean (SD) left ventricular ejection fraction (LVEF) 30% (5%)), or placebo (n = 8 , 6 men, mean (SD) age 62 (9) years, mean (SD) LVEF 28% (6%), NS vs carvedilol group). Before and 6 months after treatment, regional MBF was measured at rest and after intravenous injection of dipyridamole (Dip; 0.56 mg/kg in 4 min) by positron emission tomography and using 13N‐ammonia as a flow tracer. Exercise capacity was assessed as the time duration in a maximal bicycle exercise stress test. Results Carvedilol induced a significant decrease in heart rate at rest and during maximal exercise, and an increase in exercise capacity. Absolute MBF values did not significantly change after carvedilol or placebo treatment, either at rest or during Dip injection, although Dip‐MBF tended to improve after treatment. Coronary flow reserve significantly increased following carvedilol treatment (from 1.67 (0.63) to 2.58 (1.04), p<0.001), whereas it remained unchanged following the placebo treatment (from 1.80 (0.84) to 1.77 (0.60), NS). Stress‐induced regional perfusion defects decreased after carvedilol treatment (from 38% to 15%). Conclusions Long‐term treatment with carvedilol can significantly increase coronary flow reserve and reduce the occurrence of stress‐induced perfusion defects, suggesting a favourable effect of the drug on coronary microvascular function in patients with IDC. PMID:17237134

  7. Quantitative diagnosis of stress-induced myocardial ischemia using analysis of contrast echocardiographic parametric perfusion images.

    PubMed

    Toledo, Eran; Jacobs, Lawrence D; Lodato, Joseph A; DeCara, Jeanne M; Coon, Patrick; Mor-Avi, Victor; Lang, Roberto M

    2006-06-01

    Parametric imaging of myocardial perfusion provides useful visual information for the diagnosis of coronary artery disease (CAD). We developed a technique for automated detection of perfusion defects based on quantitative analysis of parametric perfusion images and validated it against coronary angiography. Contrast-enhanced, apical 2-, 3- and 4-chamber images were obtained at rest and with dipyridamole in 34 patients with suspected CAD. Images were analyzed to generate parametric perfusion images of the standard contrast-replenishment model parameters A, beta and A.beta. Each parametric image was divided into six segments, and mean parameter value (MPV) was calculated for each segment. Segmental MPV ratio between stress and rest was defined as a flow reserve index (FRI). Receiver operating characteristics (ROC) analysis was used in a Study group (N=17) to optimize FRI threshold and the minimal number of abnormal segments per vascular territory (LAD and non-LAD), required for automated detection of stress-induced perfusion defects. The optimized detection algorithm was then tested prospectively in the remaining 17 patients (Test group). LAD and non-LAD stenosis >70% was found in 19 and 17 patients, respectively. In the Study group, FRI threshold was: LAD=0.95 and non-LAD=0.68, minimal number of abnormal segments was four and two, correspondingly. Sensitivity, specificity and accuracy in the Test group were: 75%, 67% and 71% in the LAD, and 75%, 75% and 75% in the non-LAD territories. Automated quantitative analysis of contrast echocardiographic parametric perfusion images is feasible and may aid in the objective detection of CAD.

  8. Spray drying as a fast and simple technique for the preparation of extended release dipyridamole (DYP) microparticles in a fixed dose combination (FDC) product with aspirin.

    PubMed

    Hamishehkar, H; Valizadeh, H; Alasty, P; Monajjemzadeh, F

    2014-02-01

    Recent advances have proven that the combinational therapy of extended release dipyridamole (DYP) and fast release aspirin (ASP) can improve clinical indices of heart failure in several vascular disorders. Although pharmaceutical industries always supported fast, simple and cost saving techniques in their productions, there is no simple reported method available for this purpose. The aim of this study was to check the possibility of preparing a FDC product, containing individual dosage units of extended release DYP microparticles and fast release ASP, using the spray-drying technique as a practice compatible with pharmaceutical industries. Solid dispersions of DYP in different polymeric substances (ethyl cellulose, carnauba wax, and Eudragit PO 100), were prepared using the spray-drying method. The physicochemical properties and structure of the prepared microparticles were analyzed using different techniques, such as the particle size analyzer (PSA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X ray diffraction (XRD), and USP dissolution tester. ASP tablets were prepared individually and tested according to pharmacopeia. Results showed that prepared microparticles measured about 2.3 µm in size. Statistical analysis of the release data revealed that there is no significant difference in the mean release amount of the selected formulation compared to the innovative brand (Aggrenox®). Findings proposed a new formulation (F7) as an alternative to innovative brand and proved spray drying as a practice compatible with pharmaceutical industries and as a successful method for sustaining the DYP release rate from prepared microparticles in a FDC dosage form. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Clinical value and severity of myocardial perfusion defects in asymptomatic diabetic patients with negative or weakly positive exercise treadmill test

    PubMed Central

    Zakavi, Seyed Rasoul; Taherpour, Mehdi; Moossavi, Zohreh; Sadeghi, Ramin; Kakhki, Vahidreza Dabbagh; Rokni, Haleh

    2013-01-01

    Objective: Although coronary artery disease (CAD) is the leading cause of death in type 2 diabetic patients, it is frequently asymptomatic. Myocardial perfusion imaging (MPI) is reported to show ischemia in a significant number of asymptomatic diabetic patients. We studied the prevalence and severity of myocardial perfusion defects in asymptomatic diabetic patients and its clinical impact. Methods and patients: One hundred thirty consecutive asymptomatic patients, aged 35-65 years with type 2 diabetes mellitus and with no history of CAD and no cardiac symptoms were recruited in the study. Echocardiography, electrocardiography (ECG), routine laboratory tests and exercise treadmill test (ETT) were performed and patients with weakly positive or negative ETT underwent Dipyridamole MPI. Patients with positive ETT were referred to coronary angiography. Patients were followed for at least 17 months (mean 21.7 months) and any cardiac event was recorded. Results: We studied 81 female and 49 male patients with mean age of 51.8 years. Negative, weakly positive and positive ETT result was noted in 74.3%, 15% and 10.7% respectively. 75% of patients with positive ETT had coronary artery disease in angiography. Gated myocardial perfusion SPECT was done in 106 patients. MPI showed reversible defect in 26.9% of the patients with a mean summed stress score of 3.3±1.8. Follow up completed in 112 patients and only one patient with abnormal MPI underwent coronary angiography followed by PTCA. No cardiac death, MI, UA or hospital admission occurred among our patients during follow up (17-26 months). Mean stress end diastolic volume (EDV) was significantly higher in patients with reversible defect compared to patients without reversible defect based on MPI findings (62.0±31.6 Vs 48.5±18.4 ml, P=0.04). Blood glucose and HbA1c were significantly higher in patients with ischemia compared to patients without ischemia (P<0.05). Meanwhile the ratio of TG to HDL was 6.06±3.2 in ischemic

  10. Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block

    PubMed Central

    Falcão, Andréa; Chalela, William; Giorgi, Maria Clementina; Imada, Rodrigo; Soares, José; Do Val, Renata; Oliveira, Marco Antonio; Izaki, Marisa; Filho, Roberto Kalil; Meneghetti, José C

    2015-01-01

    OBJECTIVES: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. OBJECTIVE: We sought to investigate rubidium-82 (82Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. METHODS: Thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82Rb-positron emission tomography studies and without left bundle branch block (GII). RESULTS: Stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p<0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). CONCLUSION: The data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with

  11. Morphological aspects of myocardial bridges.

    PubMed

    Lujinović, Almira; Kulenović, Amela; Kapur, Eldan; Gojak, Refet

    2013-11-01

    Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the "tunnel" segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. The studied material contained 30 human hearts received from the Department of Anatomy. The hearts were preserved 3 to 5 days in 10% formalin solution. Thereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. The angle between the myocardial bridge fibre axis and other axis of the crossed blood vessel was measured by a goniometer. The presence of the bridges was confirmed in 53.33% of the researched material, most frequently (43.33%) above the anterior interventricular branch. The mean length of the bridges was 14.64 ± 9.03 mm and the mean thickness was 1.23 ± 1.32 mm. Myocardial bridge fibres pass over the descending blood vessel at the angle of 10-90 degrees. The results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the difference is not significant in relation to bridges located on other branches. The results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel.

  12. Morphological aspects of myocardial bridges

    PubMed Central

    Lujinović, Almira; Kulenović, Amela; Kapur, Eldan; Gojak, Refet

    2013-01-01

    Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the “tunnel” segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. The studied material contained 30 human hearts received from the Department of Anatomy. The hearts were preserved 3 to 5 days in 10% formalin solution. Thereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. The angle between the myocardial bridge fibre axis and other axis of the crossed blood vessel was measured by a goniometer. The presence of the bridges was confirmed in 53.33% of the researched material, most frequently (43.33%) above the anterior interventricular branch. The mean length of the bridges was 14.64±9.03 mm and the mean thickness was 1.23±1.32 mm. Myocardial bridge fibres pass over the descending blood vessel at the angle of 10-90 degrees. The results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the difference is not significant in relation to bridges located on other branches. The results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel. PMID:24289755

  13. Paraganglioma causing a myocardial infarction

    PubMed Central

    DeMers, Gerard; Portouw, Steve

    2012-01-01

    Paragangliomas, extra-adrenal pheochromocytomas, are rare and classically associated with sustained or paroxysmal hypertension, headache, perspiration, palpitations, and anxiety. A 49-year-old male, parachute instructor, likely developed a hypertensive emergency when deploying his parachute leading to a myocardial infarction. A para-aortic tumor was incidentally discovered during the patient's emergency department work-up and was eventually surgically resected. He had no evidence of coronary disease during his evaluation. This case shows that a myocardial infarction may be the initial manifestation of these neuroendocrine tumors. Hypertensive emergency, much less elevated blood pressure may not be present at time of presentation. PMID:22787353

  14. Thallium-201 myocardial scintigraphy in acute myocardial infarction and ischemia

    SciTech Connect

    Wackers, F.J.

    1982-04-01

    Thallium-201 scintigraphy provides a sensitive and reliable method of detecting acute myocardial infarction and ischemia when imaging is performed with understanding of the temporal characteristics and accuracy of the technique. The results of scintigraphy are related to the time interval between onset of symptoms and time of imaging. During the first 6 hr after chest pain almost all patients with acute myocardial infarction and approximately 50% of the patients with unstable angina will demonstrate /sup 201/TI pefusion defects. Delayed imaging at 2-4 hr will permit distinction between ischemia and infarction. In patients with acute myocardial infarction, the size of the perfusion defect accurately reflects the extent of the infarcted and/or jeopardized myocardium, which may be used for prognostic stratification. In view of the characteristics of /sup 201/TI scintigraphy, the most practical application of this technique is in patients in whom myocardial infarction has to be ruled out, and for early recognition of patients at high risk for complications.

  15. Spousal Adjustment to Myocardial Infarction.

    ERIC Educational Resources Information Center

    Ziglar, Elisa J.

    This paper reviews the literature on the stresses and coping strategies of spouses of patients with myocardial infarction (MI). It attempts to identify specific problem areas of adjustment for the spouse and to explore the effects of spousal adjustment on patient recovery. Chapter one provides an overview of the importance in examining the…

  16. Myocardial revascularization in Jehovah Witnesses.

    PubMed

    Seifert, P E; Auer, J E; Hohensee, P

    1989-04-01

    The refusal of certain patients to accept blood transfusions need not be a deterrent to surgery. We report on nine Jehovah's Witnesses who over a one-year period underwent myocardial revascularization without significant blood loss or decrease in hematocrit values.

  17. Imaging techniques for myocardial inflammation

    SciTech Connect

    O'Connell, J.B.; Henkin, R.E.; Robinson, J.A.

    1986-03-01

    Dilated cardiomyopathy (DC) represents a heterogeneous group of disorders which results in morbidity and mortality in young individuals. Recent evidence suggests that a subset of these patients have histologic evidence of myocarditis which is potentially treatable with immunosuppression. The identification of myocardial inflammation may therefore lead to development of therapeutic regimens designed to treat the cause rather than the effect of the myocardial disease. Ultimately, this may result in improvement in the abysmal prognosis of DC. The currently accepted technique for identification of active myocardial inflammation is endomyocardial biopsy. This technique is not perfect, however, since pathologic standards for the diagnosis of myocarditis have not been established. Furthermore, focal inflammation may give rise to sampling error. The inflammation-avid radioisotope gallium-67 citrate has been used as an adjunct to biopsy improving the yield of myocarditis from 7 percent to 36 percent. Serial imaging correlates well to biopsy results. Future studies are designed to study the applicability of lymphocyte labelling techniques to myocardial inflammatory disease.

  18. Severe Hypokalemia Masquerading Myocardial Ischemia

    PubMed Central

    Petrov, Daniel Bogdanov; Sardovski, Svetlozar Ivanov; Milanova, Maria Hristova

    2012-01-01

    An advanced degree of body potassium deficit may produce striking changes in the electrocardiogram (ECG). These changes can result in incidental findings on the 12-lead ECG or precipitate potentially life-threatening dysrhythmias. Although usually readily recognized, at times these abnormalities may be confused with myocardial ischemia. The object was to report a case of severe hypokalemia mimicking myocardial ischemia. A 33-year-old, previously healthy man, presented to the Emergency Department (ED) with a progressive weakness and chest discomfort. The electrocardiogram showed a marked ST-segment depression in leads II, III, aVF, V1-V6. The initial diagnosis was non ST-elevation myocardial infarction. Echocardiography was normal and troponin levels were within normal limits. A more detailed history revealed that the patient had an episode of acute gastroenteritis with diarrhea and vomiting. Serum chemistries were notable for a potassium concentration of 1,8 mmol per liter. With aggressive electrolyte correction, the ECG abnormalities reverted as potassium levels normalized. Hypokalemia induced ST-segment depression may simulate myocardial ischemia. The differential diagnosis might be difficult, especially in the cases when ST changes are accompanied with chest discomfort.

  19. Myocardial contractility in the stress echo lab: from pathophysiological toy to clinical tool

    PubMed Central

    2013-01-01

    Up-regulation of Ca2+ entry through Ca2+ channels by high rates of beating is involved in the frequency-dependent regulation of contractility: this process is crucial in adaptation to exercise and stress and is universally known as force-frequency relation (FFR). Disturbances in calcium handling play a central role in the disturbed contractile function in myocardial failure. Measurements of twitch tension in isolated left-ventricular strips from explanted cardiomyopathic hearts compared with non-failing hearts show flat or biphasic FFR, while it is up-sloping in normal hearts. Starting in 2003 we introduced the FFR measurement in the stress echo lab using the end-systolic pressure (ESP)/End-systolic volume index (ESVi) ratio (the Suga index) at increasing heart rates. We studied a total of 2,031 patients reported in peer-reviewed journals: 483 during exercise, 34 with pacing, 850 with dobutamine and 664 during dipyridamole stress echo. We demonstrated the feasibility of FFR in the stress echo lab, the clinical usefulness of FFR for diagnosing latent contractile dysfunction in apparently normal hearts, and residual contractile reserve in dilated idiopathic and ischemic cardiomyopathy. In 400 patients with left ventricular dysfunction (ejection fraction 30 ± 9%) with negative stress echocardiography results, event-free survival was higher (p < 0.001) in patients with ΔESPVR (the difference between peak and rest end-systolic pressure-volume ratio, ESPVR) ≥ 0.4 mmHg/mL/m2. The prognostic stratification of patients was better with FFR, beyond the standard LV ejection fraction evaluation, also in the particular settings of severe mitral regurgitation or diabetics without stress-induced ischemia. In the particular setting of selection of heart transplant donors, the stress echo FFR was able to correctly select 34 marginal donor hearts efficiently transplanted in emergency recipients. Starting in 2007, we introduced an operator-independent cutaneous sensor

  20. Myocardial contractility in the stress echo lab: from pathophysiological toy to clinical tool.

    PubMed

    Bombardini, Tonino; Zoppè, Monica; Ciampi, Quirino; Cortigiani, Lauro; Agricola, Eustachio; Salvadori, Stefano; Loni, Tiziana; Pratali, Lorenza; Picano, Eugenio

    2013-11-18

    Up-regulation of Ca2+ entry through Ca2+ channels by high rates of beating is involved in the frequency-dependent regulation of contractility: this process is crucial in adaptation to exercise and stress and is universally known as force-frequency relation (FFR). Disturbances in calcium handling play a central role in the disturbed contractile function in myocardial failure. Measurements of twitch tension in isolated left-ventricular strips from explanted cardiomyopathic hearts compared with non-failing hearts show flat or biphasic FFR, while it is up-sloping in normal hearts. Starting in 2003 we introduced the FFR measurement in the stress echo lab using the end-systolic pressure (ESP)/End-systolic volume index (ESVi) ratio (the Suga index) at increasing heart rates. We studied a total of 2,031 patients reported in peer-reviewed journals: 483 during exercise, 34 with pacing, 850 with dobutamine and 664 during dipyridamole stress echo. We demonstrated the feasibility of FFR in the stress echo lab, the clinical usefulness of FFR for diagnosing latent contractile dysfunction in apparently normal hearts, and residual contractile reserve in dilated idiopathic and ischemic cardiomyopathy. In 400 patients with left ventricular dysfunction (ejection fraction 30 ± 9%) with negative stress echocardiography results, event-free survival was higher (p < 0.001) in patients with ΔESPVR (the difference between peak and rest end-systolic pressure-volume ratio, ESPVR) ≥ 0.4 mmHg/mL/m2. The prognostic stratification of patients was better with FFR, beyond the standard LV ejection fraction evaluation, also in the particular settings of severe mitral regurgitation or diabetics without stress-induced ischemia. In the particular setting of selection of heart transplant donors, the stress echo FFR was able to correctly select 34 marginal donor hearts efficiently transplanted in emergency recipients. Starting in 2007, we introduced an operator-independent cutaneous sensor

  1. Myocardial protection in heart surgery.

    PubMed

    Mentzer, Robert M

    2011-01-01

    One of the unmet clinical needs in heart surgery is the prevention of myocardial stunning and necrosis that occurs as a result of ischemia-reperfusion. Myocardial stunning, a frequent consequence after heart surgery, is characterized by a requirement for postoperative inotropic support despite a technically satisfactory heart operation. In high-risk patients with marginal cardiac reserve, stunning is a major cause of prolonged critical care and may be associated with as much as a 5-fold increase in mortality. In contrast, the frequency of myocardial necrosis (myocardial infarction [MI]) after cardiac surgery is less appreciated and its consequences are much more subtle. The consequences may not be apparent for months to years. While we now have a much better understanding of the molecular mechanisms underlying myocardial stunning and MI, we still have no effective way to prevent these complications, nor a consistently effective means to engage the well-studied endogenous mechanisms of cardioprotection. The failure to develop clinically effective interventions is multifactorial and can be attributed to reliance on findings obtained from subcellular and cellular studies, to drawing conclusions from preclinical large animal studies that have been conducted in a disease-free state, and to accepting less than robust surrogate markers of injury in phase II clinical trials. These factors also explain the disappointing failure to identify effective adjuvant therapy in the setting of percutaneous coronary revascularization for acute MI (AMI) and reperfusion injury. These issues have contributed to the disappointing outcomes of large and costly phase III trials, resulting in a lack of enthusiasm on the part of the pharmaceutical industry to engage in further drug development for this indication. The purpose of this review is to (1) define the scope of the clinical problem; (2) summarize the outcomes of selected phases II and III clinical trials; and (3) identify the gap that

  2. Myocardial disarray. A critical review.

    PubMed Central

    Becker, A E; Caruso, G

    1982-01-01

    Myocardial disarray or disorganisation is at present a contentious topic, not least because its value as a clinical marker for hypertrophic cardiomyopathy has changed considerably over the years. Initially observed as one of the features of asymmetric septal hypertrophy, disarray has since been promoted as its pathognomonic histological feature, regarded by some observers as the morphological manifestation of a genetically transmitted myocardial defect. Recently, however, it has become evident that myocardial disarray is not limited to hypertrophic cardiomyopathy, but is encountered in hearts with both congenital and acquired conditions, and is also observed in normal hearts. The specificity of disarray for hypertrophic cardiomyopathy is thus seriously questioned. Latterly, it has been suggested that disarray, judged from through-and-through sections of the ventricular midseptum is a highly specific and sensitive marker of hypertrophic cardiomyopathy when considered in quantitative rather than qualitative fashion. The present study sets out to answer the question whether disarray could be the histological expression of the normal but intricate fibre architecture of the heart, a consideration also initiated by debatable definitions of normality and abnormality of myocardial histology. Gross fibre dissections in five normal hearts showed that many sites occurred in which disarray was a natural phenomenon. In five more hearts it was found that the plane of section of a tissue block might profoundly influence the histology. In fact, tissue cubicles sampled from different faces showed a change in histology in the vast majority. Thus the diagnostic significance of myocardial disarray as a marker of hypertrophic cardiomyopathy in the clinical setting almost vanishes; a change in orientation of a tissue section may actually turn "normality" into "disarray". Images PMID:7044398

  3. Positron Emission Tomography for the Assessment of Myocardial Viability

    PubMed Central

    2010-01-01

    , harmonic imaging, and power doppler imaging may help to improve the diagnostic accuracy of echocardiographic assessment of myocardial viability. Stress Echocardiography with Contrast Intravenous contrast agents, which are high molecular weight inert gas microbubbles that act like red blood cells in the vascular space, can be used during echocardiography to assess myocardial viability. These agents allow for the assessment of myocardial blood flow (perfusion) and contractile function (as described above), as well as the simultaneous assessment of perfusion to make it possible to distinguish between stunned and hibernating myocardium. SPECT SPECT can be performed using thallium-201 (Tl-201), a potassium analogue, or technetium-99 m labelled tracers. When Tl-201 is injected intravenously into a patient, it is taken up by the myocardial cells through regional perfusion, and Tl-201 is retained in the cell due to sodium/potassium ATPase pumps in the myocyte membrane. The stress-redistribution-reinjection protocol involves three sets of images. The first two image sets (taken immediately after stress and then three to four hours after stress) identify perfusion defects that may represent scar tissue or viable tissue that is severely hypoperfused. The third set of images is taken a few minutes after the re-injection of Tl-201 and after the second set of images is completed. These re-injection images identify viable tissue if the defects exhibit significant fill-in (> 10% increase in tracer uptake) on the re-injection images. The other common Tl-201 viability imaging protocol, rest-redistribution, involves SPECT imaging performed at rest five minutes after Tl-201 is injected and again three to four hours later. Viable tissue is identified if the delayed images exhibit significant fill-in of defects identified in the initial scans (> 10% increase in uptake) or if defects are fixed but the tracer activity is greater than 50%. There are two technetium-99 m tracers: sestamibi (MIBI

  4. The Japanese aggrenox (extended-release dipyridamole plus aspirin) stroke prevention versus aspirin programme (JASAP) study: a randomized, double-blind, controlled trial.

    PubMed

    Uchiyama, Shinichiro; Ikeda, Yasuo; Urano, Yasuhisa; Horie, Yoshiharu; Yamaguchi, Takenori

    2011-01-01

    Despite improvements in treatment, stroke still carries a high death toll and disability in Asia. Extended-release dipyridamole (ER-DP) plus acetylsalicylic acid (ASA) has consistently been shown to be superior over conventional platelet inhibition by ASA. ER-DP plus ASA is well established in the secondary prevention of stroke in a lot of countries including the USA and Europe. DP has an established benefit in the treatment of heart disease in Japan; however, for the prevention of stroke, the fixed-dose combination of ER-DP plus ASA has only been investigated in a small number of patients in Japan. The aim of this double-blind, randomized clinical trial was to investigate the efficacy and safety of ER-DP plus ASA versus 81 mg ASA over 1 year. The primary end point of this study was the event rate of recurrent ischemic stroke (fatal or nonfatal) using the Kaplan-Meier method and Cox regression analysis. Of the 1,294 enrolled patients, the primary end point was analyzed in 652 patients in the ER-DP plus ASA group and 639 in the ASA group. The incidence of ischemic stroke was 6.9% for ER-DP plus ASA and 5.0% for ASA with a hazard ratio of 1.47 (95% confidence interval 0.93-2.31) for the primary end point. The ASA treatment group was found to have a lower than expected yearly event rate, compared to other studies in Japanese stroke patients. Noninferiority of ER-DP plus ASA versus ASA could not be shown. The risks of major bleeding events and intracranial hemorrhage were found to be similar between the treatment arms. There were 4 deaths (0.6%) in the ER-DP plus ASA group and 10 (1.6%) in the ASA group. The results of the study are inconclusive. Noninferiority of ER-DP plus ASA versus ASA could not be established, a difference between treatments could not be shown for the primary end point. Possible reasons for this result include a small sample size, low event rates and too short a treatment duration (ClinicalTrials. gov number, NCT00311402). Copyright © 2011 S

  5. Preparation and in vitro-in vivo evaluation of none gastric resident dipyridamole (DIP) sustained-release pellets with enhanced bioavailability.

    PubMed

    Xu, Lishuang; Luo, Yanfei; Feng, Jia; Xu, Ming; Tao, Xiaoguang; He, Haibing; Tang, Xing

    2012-01-17

    The objective of this study was to develop none gastric resident sustained-release pellets loaded with dipyridamole with a high bioavailability. Two different kinds of core pellets, one containing citric acid as a pH-modifier (CAP) and, the other without pH-modifier (NCAP) were prepared by extrusion-spheronization and then coated with mixtures of enteric soluble and insoluble polymers (referred to as CAP(1) and NCAP(1)) or insoluble polymer alone (referred to as CAP(2) and NCAP(2)). The relative bioavailability of the sustained-release pellets was studied in fasted beagle dogs after oral administration using a commercially available immediate release tablet (IRT) as a reference. The in vitro release, in vivo absorption and in vitro-in vivo correlation were also evaluated. Results revealed that the plasma drug concentrations after administration of CAP(2), NCAP(1) and NCAP(2) were undetectable, indicating that the drug release was almost zero from the preparations throughout the gastro-intestinal tract. The C(max), T(max) and AUC((0→24)) of CAP(1) were 0.78 ± 0.23 (μg/ml), 3.80 ± 0.30 (h), and 6.74 ± 0.47 (μg/mlh), respectively. While the corresponding values were 2.23 ± 0.32 (μg/ml), 3.00 ± 0.44 (h) and 9.42 ± 0.69 (μg/mlh) for IRT. The relative bioavailability of CAP(1) was 71.55% compared with IRT. By combined incorporation of a pH-modifier into the core of pellets to modify the inner micro-environment and employing mixtures of enteric soluble and insoluble polymers as a retarding layer, drugs with high solubility in stomach and limited solubility in small intestine, such as DIP, could be successfully formulated as sustained release preparations with no pH-dependence in drug release and enhanced bioavailability.

  6. Criteria for definition of regional functional improvement on quantitative post-stress gated myocardial SPET after bypass surgery in patients with ischaemic cardiomyopathy.

    PubMed

    Lee, Dong Soo; Cheon, Gi Jeong; Paeng, Jin Chul; Kim, Ki Bong; Chung, June-Key; Lee, Myung Chul

    2002-08-01

    Myocardial viability can be defined as functional improvement of dysfunctional myocardium after revascularization. The purpose of this study was to define the optimal criteria for definition of regional functional improvement after coronary artery bypass graft (CABG) surgery on quantitative gated single-photon emission tomography (SPET). Thirty-two patients (26 men, 6 women; age 56 +/- 13 years) with coronary artery disease (three-vessel disease, 17; two-vessel disease, 15; previous history of myocardial infarction, 9) and severe left ventricular dysfunction (LVEF < or = 35%) underwent CABG. Rest thallium-201/dipyridamole stress technetium-99m methoxyisobutylisonitrile gated myocardial SPET was performed before and 3 months after CABG. Global LV functional improvement was defined as either an improvement in LVEF of 10% ( n = 15) or an improvement in LVEF of 5% combined with a decrease in end-systolic volume of 10 ml ( n = 2) after CABG on quantitative gated SPET. Postoperative regional wall thickening improvement (DeltaRWT), regional wall motion improvement (DeltaRWM) and regional resting (DeltaRP) and stress perfusion improvement (DeltaRstrP) were used to determine global functional improvement by ROC curve analysis, and the optimal criteria for definition of viable regional dysfunctional myocardium were defined on the ROC curves. Correlations were verified by determining the number of improved myocardial regions and LVEF improvement. LVEF was improved from 25% +/- 6% to 34% +/- 11% after CABG. A total of 229 segments were dysfunctional (wall motion < or = 2 mm, thickening < or = 20%) before CABG. On ROC curve analysis using global functional improvement as an indicator of viability, the areas under the ROC curves (AUCs) of DeltaRWT and DeltaRWM were 0.717 and 0.620, respectively. The AUC of DeltaRWT was significantly larger than that of DeltaRWM ( P = 0.009) and the optimal cut-off value of DeltaRWT was 15%. The AUCs of DeltaRP and DeltaRstrP were not significant

  7. Ribose facilitates thallium-201 redistribution in patients with coronary artery disease

    SciTech Connect

    Perlmutter, N.S.; Wilson, R.A.; Angello, D.A.; Palac, R.T.; Lin, J.; Brown, B.G. )

    1991-02-01

    To investigate whether i.v. infusion of ribose, an adenine nucleotide precursor, postischemia facilitates thallium-201 (201Tl) redistribution and improves identification of ischemic myocardium in patients with coronary artery disease (CAD), 17 patients underwent two exercise 201Tl stress tests, performed 1-2 wk apart. After immediate postexercise planar imaging, patients received either i.v. ribose (3.3 mg/kg/min x 30 min) or saline as a control. Additional imaging was performed 1 and 4 hr postexercise. Reversible defects were identified by count-profile analysis. Significantly more (nearly twice as many) reversible 201Tl defects were identified on the post-ribose images compared to the post-saline (control) images at both 1 and 4 hr postexercise (p less than 0.001). Quantitative analyses of the coronary arteriogram was available in 13 patients and confirmed that the additional reversible defects were in myocardial regions supplied by stenosed arteries. We conclude that ribose appears to facilitate 201Tl redistribution in patients with CAD and enhances identification of ischemic myocardium.

  8. Abnormal thallium 201 scintigraphy during low-dose vasopressin infusions

    SciTech Connect

    Davison, R.; Kaplan, K.; Bines, A.; Spies, S.; Reed, M.T.; Lesch, M.

    1986-12-01

    Thallium 201 (/sup 201/Tl) myocardial scans were obtained in 16 patients just prior to the discontinuation of a vasopressin infusion (.1 to .2 units/min) administered for the treatment of upper gastrointestinal bleeding. Repeat scintigraphy was performed two to three hours after the vasopressin was stopped. Eleven of the 16 patients (69 percent) demonstrated areas of decreased myocardial /sup 201/Tl uptake that resolved after the infusion was stopped. Heart rate-blood pressure product was significantly lower at the time of the second scan. Autopsies were secured in three of 11 scan-positive patients: one had severe coronary artery obstruction, one nonsignificant disease, and another had normal coronary arteries. Vasopressin, even at low doses, can induce abnormalities in myocardial perfusion that are probably mediated by a direct effect on the coronary circulation. They are usually not detectable by routine monitoring techniques and conceivably form the basis for the cardiovascular morbidity associated with the use of this agent.

  9. [Premonitory sign of myocardial rupture].

    PubMed

    Lauten, A; Dittrich, P

    1975-10-01

    It is reported on 14 cases in which a rupture of the myocardium occurred following a myocardial infarction. The moment of the appearance as well as anamnestic and clinical peculiarities are examined. As the only usable symptom of the rupture the symptomatology of the electromechanic dissociation must be taken into consideration. Finally it is referred to the on principle possible operative consequences of the rupture of the myocardium (oversewing or infarctetomy).

  10. Myocardial structure and matrix metalloproteinases.

    PubMed

    Aggeli, C; Pietri, P; Felekos, I; Rautopoulos, L; Toutouzas, K; Tsiamis, E; Stefanadis, C

    2012-01-01

    Metalloproteinases (MMPs) are enzymes which enhance proteolysis of extracellular matrix proteins. The pathophysiologic and prognostic role of MMPs has been demonstrated in numerous studies. The present review covers a wide a range of topics with regards to MMPs structural and functional properties, as well as their role in myocardial remodeling in several cardiovascular diseases. Moreover, the clinical and therapeutic implications from their assessment are highlighted.

  11. Tachyarrhythmias in acute myocardial infarction.

    PubMed

    McLean, K H; Bett, J N; Saltups, A

    1975-02-01

    In 1505 patients with acute myocardial infarction (MI) serious ventricular arrhythmias were commoner in those with transmural ECG changes, and were associated with an increase in mortality and in the incidence of left ventricular failure (LVF) as well as higher peak serum lactic dehydrogenase (LDH) levels. Atrial fibrillation (AF) occurred more often in older patients and in those with LVF and clinical evidence of pericarditis.

  12. Functional tests for myocardial ischemia

    SciTech Connect

    Levinson, J.R.; Guiney, T.E.; Boucher, C.A. )

    1991-01-01

    Functional tests for myocardial ischemia are numerous. Most depend upon a combination of either exercise or pharmacologic intervention with analysis of the electrocardiogram, of regional perfusion with radionuclide imaging, or of regional wall motion with radionuclide imaging or echocardiography. While each test has unique features, especially at the research level, they are generally quite similar in clinical practice, so the clinician is advised to concentrate on one or two in which local expertise is high.22 references.

  13. [Psychiatric disorders following myocardial infarction].

    PubMed

    Meincke, Ulrich; Hoff, Paul

    2006-05-15

    The number of patients who survive acute myocardial infarction has increased during recent decades. In addition, demographic development results in a rising incidence of cardiovascular diseases. Based on these facts, also the significance of psychiatric disorders is growing that may occur after myocardial infarction, such as depression, posttraumatic stress and anxiety disorders. Physicians are faced with the challenge to identify these clinical entities, that show a syndromal overlap with somatic complaints after myocardial infarction. After differentiation prompt start of adequate psychiatric-psychotherapeutic interventions is of relevance, not only regarding the patient's quality of life, but also in terms of cardiovascular prognosis. Indeed, depressive and anxiety disorders are known to be associated with a poor compliance as for rehabilitation and secondary prevention of cardiovascular disorders. Moreover, some studies suggest depression to be an independent risk factor of coronary heart disease. Consequently, early recognition and treatment, most often primarily in the hands of internists and cardiologists, are of enormous importance for the course and prognosis of the psychiatric disorder but also of cardiovascular disease.

  14. Myocardial Infarction in the Elderly

    PubMed Central

    Carro, Amelia; Kaski, Juan Carlos

    2011-01-01

    Advances in pharmacological treatment and effective early myocardial revascularization have –in recent years- led to improved clinical outcomes in patients with acute myocardial infarction (AMI). However, it has been suggested that compared to younger subjects, elderly AMI patients are less likely to receive evidence-based treatment, including myocardial revascularization therapy. Several reasons have been postulated to explain this trend, including uncertainty regarding the true benefits of the interventions commonly used in this setting as well as increased risk mainly associated with comorbidities. The diagnosis, management, and post-hospitalization care of elderly patients presenting with an acute coronary syndrome pose many difficulties at present. A complex interplay of variables such as comorbidities, functional and socioeconomic status, side effects associated with multiple drug administration, and individual biologic variability, all contribute to creating a complex clinical scenario. In this complex setting, clinicians are often required to extrapolate evidence-based results obtained in cardiovascular trials from which older patients are often, implicitly or explicitly, excluded. This article reviews current recommendations regarding management of AMI in the elderly. PMID:22396870

  15. Myocardialization of the cardiac outflow tract

    NASA Technical Reports Server (NTRS)

    van den Hoff, M. J.; Moorman, A. F.; Ruijter, J. M.; Lamers, W. H.; Bennington, R. W.; Markwald, R. R.; Wessels, A.

    1999-01-01

    During development, the single-circuited cardiac tube transforms into a double-circuited four-chambered heart by a complex process of remodeling, differential growth, and septation. In this process the endocardial cushion tissues of the atrioventricular junction and outflow tract (OFT) play a crucial role as they contribute to the mesenchymal components of the developing septa and valves in the developing heart. After fusion, the endocardial ridges in the proximal portion of the OFT initially form a mesenchymal outlet septum. In the adult heart, however, this outlet septum is basically a muscular structure. Hence, the mesenchyme of the proximal outlet septum has to be replaced by cardiomyocytes. We have dubbed this process "myocardialization." Our immunohistochemical analysis of staged chicken hearts demonstrates that myocardialization takes place by ingrowth of existing myocardium into the mesenchymal outlet septum. Compared to other events in cardiac septation, it is a relatively late process, being initialized around stage H/H28 and being basically completed around stage H/H38. To unravel the molecular mechanisms that are responsible for the induction and regulation of