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Sample records for adenosine myocardial perfusion

  1. 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.

  2. Myocardial perfusion scintigraphy during maximal coronary artery vasodilation with adenosine

    SciTech Connect

    Verani, M.S.; Mahmarian, J.J. )

    1991-05-21

    Pharmacologic coronary vasodilation as an adjunct to thallium-201 myocardial perfusion scintigraphy provides an important alternative form of stress that has been increasingly used in patients unable to perform an exercise stress test. Although dipyridamole has traditionally been used for this purpose, there are several compelling reasons why adenosine may be a preferable agent. First, dipyridamole acts by blocking the reuptake and transport of adenosine, which is the effective substance responsible for coronary vasodilation. Second, exogenous adenosine has a very short half-life (less than 2 seconds), which explains its very short duration of action as well as the brief, self-limiting duration of its side effects. Third, the adenosine infusion is controllable and may be increased or decreased as desired. Fourth, the coronary vasodilation induced by the doses of adenosine we recommend (140 micrograms/kg/min) may be more profound than that induced by the standard dipyridamole dose. Our experience to date, with nearly 1,000 patients studied, shows the adenosine thallium-201 test to be practical and well tolerated, with high sensitivity (87%) and specificity (94%) for detecting coronary artery disease.

  3. High-frequency Electrocardiogram Analysis in the Ability to Predict Reversible Perfusion Defects during Adenosine Myocardial Perfusion Imaging

    NASA Technical Reports Server (NTRS)

    Tragardh, Elin; Schlegel, Todd T.; Carlsson, Marcus; Pettersson, Jonas; Nilsson, Klas; Pahlm, Olle

    2007-01-01

    Background: A previous study has shown that analysis of high-frequency QRS components (HF-QRS) is highly sensitive and reasonably specific for detecting reversible perfusion defects on myocardial perfusion imaging (MPI) scans during adenosine. The purpose of the present study was to try to reproduce those findings. Methods: 12-lead high-resolution electrocardiogram recordings were obtained from 100 patients before (baseline) and during adenosine Tc-99m-tetrofosmin MPI tests. HF-QRS were analyzed regarding morphology and changes in root mean square (RMS) voltages from before the adenosine infusion to peak infusion. Results: The best area under the curve (AUC) was found in supine patients (AUC=0.736) in a combination of morphology and RMS changes. None of the measurements, however, were statistically better than tossing a coin (AUC=0.5). Conclusion: Analysis of HF-QRS was not significantly better than tossing a coin for determining reversible perfusion defects on MPI scans.

  4. [Thallium-201 myocardial perfusion imaging during adenosine-induced coronary vasodilation in patients with ischemic heart disease].

    PubMed

    Takeishi, Y; Chiba, J; Abe, S; Ikeda, K; Tonooka, I; Komatani, A; Takahashi, K; Nakagawa, Y; Shiraishi, T; Tomoike, H

    1992-09-01

    201Tl myocardial perfusion imaging during adenosine infusion was performed in consecutive 55 patients with suspected coronary artery disease. Adenosine was infused intravenously at a rate of 0.14 mg/kg/min for 6 minutes and a dose of 111 MBq of 201Tl was administered in a separate vein at the end of third minute of infusion. Myocardial SPECT imaging was begun 5 minutes and 3 hours after the end of adenosine infusion. For evaluating the presence of perfusion defects, 2 short axis images at the basal and apical levels and a vertical long axis image at the mid left ventricle were used. The regions with decreased 201Tl uptake were assessed semi-quantitatively. Adenosine infusion caused a slight reduction in systolic blood pressure and an increase in heart rate. The rate pressure products increased slightly (9314 +/- 2377 vs. 10360 +/- 2148, p < 0.001). Chest pain (24%) and headache (13%) were the frequent side effects. The second-degree atrioventricular block was developed in 11 of 55 (20%) patients. All symptoms and hemodynamic changes were well tolerated and disappeared within 1 or 2 minutes after discontinuing adenosine infusion. The sensitivity and specificity for the detection of patients with coronary artery disease were 100% (31/31) and 88% (7/8), respectively. 201Tl myocardial imaging during adenosine infusion was considered to be safe and useful for evaluating the patients with ischemic heart disease. PMID:1453559

  5. Caffeine intake inverts the effect of adenosine on myocardial perfusion during stress as measured by T1 mapping.

    PubMed

    Kuijpers, Dirkjan; Prakken, Niek H; Vliegenthart, Rozemarijn; van Dijkman, Paul R M; van der Harst, Pim; Oudkerk, Matthijs

    2016-10-01

    Caffeine intake before adenosine stress myocardial perfusion imaging may cause false negative findings. We hypothesized that the antagonistic effect of caffeine can be measured by T1 relaxation times in rest and adenosine stress cardiac magnetic resonance imaging (CMR), as T1 mapping techniques are sensitive to changes in myocardial blood volume. We prospectively analyzed 105 consecutive patients with adenosine stress perfusion CMR on a 1.5-T MRI system. Rest and stress T1 mapping was performed using Modified Look-Locker Inversion recovery. T1 reactivity was defined as difference in T1rest and T1stress (∆T1). Fifteen patients drank coffee within 4 h of CMR (<4H caffeine group), and 10 patients had coffee the day before (>8H caffeine group). Comparison was made to patients without self-reported coffee intake: 50 with normal CMR (control group), 18 with myocardial ischemia, and 12 with myocardial infarction. The national review board approved the study; all patients gave written informed consent. The <4H caffeine group showed inverted ∆T1 of -7.8 % (T1rest 975 ± 42 ms, T1stress 898 ± 51 ms, p < 0.0005). The >8H caffeine group showed reduced T1 reactivity (1.8 %; T1rest 979 ms, T1stress 997 ms) compared to the controls (4.3 %; T1rest 977 ± 40 ms, T1stress 1018 ± 40 ms), p < 0.0005. Ischemic and infarcted myocardium showed minimal T1 reactivity (0.2 and 0.3 %, respectively). Caffeine intake inverts the adenosine effect during stress perfusion CMR as measured by T1 mapping. T1 reactivity can assess the adequacy of adenosine-induced stress in perfusion CMR. PMID:27473274

  6. 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.

  7. 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.

  8. Myocardial perfusion imaging using contrast echocardiography.

    PubMed

    Pathan, Faraz; Marwick, Thomas H

    2015-01-01

    Microbubbles are an excellent intravascular tracer, and both the rate of myocardial opacification (analogous to coronary microvascular perfusion) and contrast intensity (analogous to myocardial blood volume) provide unique insights into myocardial perfusion. A strong evidence base has been accumulated to show comparability with nuclear perfusion imaging and incremental diagnostic and prognostic value relative to wall motion analysis. This technique also provides the possibility to measure myocardial perfusion at the bedside. Despite all of these advantages, the technique is complicated, technically challenging, and has failed to scale legislative and financial hurdles. The development of targeted imaging and therapeutic interventions will hopefully rekindle interest in this interesting modality. PMID:25817740

  9. Myocardial perfusion scintigraphy: the evidence.

    PubMed

    Underwood, S R; Anagnostopoulos, C; Cerqueira, M; Ell, P J; Flint, E J; Harbinson, M; Kelion, A D; Al-Mohammad, A; Prvulovich, E M; Shaw, L J; Tweddel, A C

    2004-02-01

    This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by

  10. Safety of adenosine pharmacologic stress myocardial perfusion imaging in orthotopic cardiac transplant recipients: a single center experience of 102 transplant patients.

    PubMed

    Al-Mallah, Mouaz H; Arida, Muhammad; Garcia-Sayan, Enrique; Assal, Chafik; Zegarra, Gino Tapia; Czerska, Barbara; Ananthasubramaniam, Karthik

    2011-10-01

    Denervation super-sensitivity to adenosine is well described in cardiac transplant (CT) patients particularly early after transplant. The safety and hemodynamic effects of adenosine SPECT (A-SPECT) has not been described in a large series of CT patients. Single center retrospective study of 102 CT patients undergoing A-SPECT were compared to an age-gender matched patients in a 2:1 fashion who underwent A-SPECT in the same time period. Multivariate logistic regression model were used to identify independent predictors of advanced AV block. The average time from CT to A-SPECT was 8.5 ± 4.5 years. Average age was 57 years with 80% males. In comparison to the control group, adenosine infusion was associated with a higher incidence of sinus pause (4.9% vs. 0%), 2nd (11.8% vs. 4.9%) and 3rd degree AVB (2.9% vs. 0%) in CT patients (all P < 0.05). Prior use of aspirin and baseline 1st degree AVB were significant independent predictors of adenosine induced AVB. Baseline right or left bundle branch block, beta-blockers, calcium blockers or digoxin were not associated with occurrence of AVB. Only 1.9% of A-SPECT studies were terminated due to bradyarrythmia with 1 patient requiring aminophylline. There were no significant immediate or long term adverse events in these patients. Adenosine pharmacologic stress is associated with a higher incidence of AVB and sinus pause in CT patients reflecting persistence of super sensitivity late after CT. Nevertheless these bradyarrythmias are transient without any sequelae suggesting that A-SPECT can be performed safely in CT patients. PMID:21088992

  11. Myocardial perfusion imaging with 201Tl.

    PubMed

    Pagnanelli, Robert A; Basso, Danny A

    2010-03-01

    The object of this review is to provide information about (201)Tl-thallous chloride in radionuclide myocardial perfusion imaging. This technique has experienced a recent resurgence because of the shortage of (99m)Tc. After reading this article, the technologist will be able to describe the properties and uptake mechanism of (201)Tl, the procedure for myocardial perfusion imaging with this agent, and the advantages and disadvantages of thallium, compared with the technetium agents. PMID:20159930

  12. Improved exercise myocardial perfusion during lidoflazine therapy

    SciTech Connect

    Shapiro, W.; Narahara, K.A.; Park, J.

    1983-11-01

    Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise.

  13. Prognostic value of quantitative high-speed myocardial perfusion imaging

    PubMed Central

    Nakazato, Ryo; Berman, Daniel S.; Gransar, Heidi; Hyun, Mark; Miranda-Peats, Romalisa; Kite, Faith C.; Hayes, Sean W.; Thomson, Louise E.J.; Friedman, John D.; Rozanski, Alan; Slomka, Piotr J.

    2012-01-01

    Background Most studies have reported using semi-quantitative analysis to assess the prognostic utility of SPECT myocardial perfusion imaging (MPI). Thus we studied the prognostic value of fully automated quantitative analysis software applied to new solid-state, high-speed (HS) SPECT-MPI. Methods 1613 consecutive patients undergoing exercise or adenosine HS-MPI were followed for 2.6±0.5 years for all-cause mortality (ACM). Automated quantitative software was used for assessing stress total perfusion deficit (sTPD) and was compared to semi-quantitative visual analysis. MPI was characterized as 0% (normal); 1–4% (minimal perfusion defect); 5–10% (mildly abnormal); and >10% (moderately/severely abnormal). Results During follow-up, 79 patients died (4.9%). Annualized ACM increased with progressively increasing sTPD; 0% (0.87%), 1–4% (1.94%), 5–10% (3.10%) and >10% (5.33%) (log-rank p<0.0001). While similar overall findings were observed with visual analysis, only sTPD demonstrated increased risk in patients with minimal perfusion defects. In multivariable analysis, sTPD >10% was a mortality predictor (HR 3.03, 95% CI 1.30–7.09, p=0.01). Adjusted mortality rate was substantial in adenosine MPI, but low in exercise MPI (9.0% versus 1.0%, p<0.0001). Conclusions By quantitative analysis, ACM increases with increasing perfusion abnormality among patients undergoing stress HS-MPI. These findings confirm previous results obtained with visual analysis using conventional Anger camera imaging systems. PMID:23065414

  14. 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.

  15. Amelioration of adriamycin and daunorubicin myocardial toxicity by adenosine.

    PubMed

    Newman, R A; Hacker, M P; Krakoff, I H

    1981-09-01

    Primary cultures of rat myocardial cells were used to investigate the dose and time-dependent cellular enzyme release induced by either Adriamycin or daunorubicin, Concentrations of either anthracycline (1.8 or 18 microM) produced significant release of creatine phosphokinase and lactic dehydrogenase from myocardial cells within 24 hr of exposure without a detectable decrease in cell viability. Preincubation of the myocardial cells with varying concentrations of adenosine (10 microM to 1 mM) for 24 hr prior to the addition of anthracycline decreased or prevented drug-induced enzyme release. Other putative myocardial protectants, i.e., N-acetyl-L-cysteine, alpha-tocopherol, or carnitine, were ineffective in preventing anthracycline-induced enzyme release. Although adenosine was an effective myocardial protectant, it had no significant effect on cellular uptake of daunorubicin, nor did adenosine adversely affect the oncolytic activity of daunorubicin against L1210 leukemia cells in vitro. Anthramycin, another oncolytic agent having reported cardiotoxic effects, was also tested in the in vitro system. With this drug, however, no enzyme release was detected at less than lethal doses nor did adenosine have any protective potential against the toxicity of anthramycin. Finally, Adriamycin caused no significant lactic dehydrogenase release when incubated at 1.8 or 18 microM with H9c2 cells, a cell line having primarily skeletal muscle characteristics. This result suggests a specific toxicity of anthracyclines for myocardial but not skeletal muscle cells. PMID:7260911

  16. Myocardial perfusion SPECT in a case of retropulmonary looping of left coronary artery in a baby after arterial switch surgery.

    PubMed

    Padma, Subramanyam; Sundaram, Palaniswamy Shanmuga

    2014-04-01

    Pediatric myocardial perfusion imaging (MPI) is not a routine investigation in an Indian setting due to under referrals and logistic problems. However, MPI is a frequently performed and established modality of investigation in adults for the identification of myocardial ischemia and viability. We report myocardial perfusion scintigraphy in a case of retropulmonary looping of left coronary artery in a baby after arterial switch surgery. Adenosine stress MPI revealed a large infarct involving anterior segment with moderate reversible ischemia of the lateral left ventricular segment. Coronary angiogram later confirmed left main coronary artery ostial occlusion with retrograde collateral supply from dilated right coronary artery. PMID:24761067

  17. High frequency QRS ECG predicts ischemic defects during myocardial perfusion imaging

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphological score that incorporated the number, type and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square (RMS) voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P less than 0.00l). Analysis of 12-lead HF QRS ECG is highly sensitive and specific for detecting ischemic perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

  18. High frequency QRS ECG predicts ischemic defects during myocardial perfusion imaging

    NASA Technical Reports Server (NTRS)

    Rahman, Atiar

    2006-01-01

    Background: Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). Methods and Results: 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphological score that incorporated the number, type and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square (RMS) voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P<0.001). Conclusions: Analysis of 12-lead HF QRS ECG is highly sensitive and specific for detecting ischemic perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

  19. New imaging technology: measurement of myocardial perfusion by contrast echocardiography

    NASA Technical Reports Server (NTRS)

    Rubin, D. N.; Thomas, J. D.

    2000-01-01

    Myocardial perfusion imaging has long been a goal for the non-invasive echocardiographic assessment of the heart. However, many factors at play in perfusion imaging have made this goal elusive. Harmonic imaging and triggered imaging with newer contrast agents have made myocardial perfusion imaging potentially practical in the very near future. The application of indicator dilution theory to the coronary circulation and bubble contrast agents is fraught with complexities and sources of error. Therefore, quantification of myocardial perfusion by non-invasive echocardiographic imaging requires further investigation in order to make this technique clinically viable.

  20. Use of ultrafast computed tomography to quantitate regional myocardial perfusion: a preliminary report

    SciTech Connect

    Rumberger, J.A.; Feiring, A.J.; Lipton, M.J.; Higgins, C.B.; Ell, S.R.; Marcus, M.L.

    1987-01-01

    The purpose of this study was to assess the potential for rapid acquisition computed axial tomography (Imatron C-100) to quantify regional myocardial perfusion. Myocardial and left ventricular cavity contrast clearance curves were constructed after injecting nonionic contrast (1 ml/kg over 2 to 3 seconds) into the inferior vena cava of six anesthetized, closed chest dogs (n = 14). Independent myocardial perfusion measurements were obtained by coincident injection of radiolabeled microspheres into the left atrium during control, intermediate and maximal myocardial vasodilation with adenosine (0.5 to 1.0 mg/kg per min, intravenously, respectively). At each flow state, 40 serial short-axis scans of the left ventricle were taken near end-diastole at the midpapillary muscle level. Contrast clearance curves were generated and analyzed from the left ventricular cavity and posterior papillary muscle regions after excluding contrast recirculation and minimizing partial volume effects. The area under the curve (gamma variate function) was determined for a region of interest placed within the left ventricular cavity. Characteristics of contrast clearance data from the posterior papillary muscle region that were evaluated included the peak myocardial opacification, area under the contrast clearance curve and a contrast clearance time defined by the full width/half maximal extent of the clearance curve. Myocardial perfusion (microspheres) ranged from 35 to 450 ml/100 g per min (mean 167 +/- 125).

  1. Myocardial perfusion of infarcted and normal myocardium in propofol-anesthetized minipigs using (82)Rubidium PET.

    PubMed

    Rasmussen, Thomas; Follin, Bjarke; Kastrup, Jens; Christensen, Thomas Emil; Hammelev, Karsten Pharao; Kjær, Andreas; Hasbak, Philip

    2016-06-01

    Cardiac Rubidium-82 ((82)Rb) positron-emission-tomography (PET) is a good method for quantification of myocardial blood flow in man. Quantification of myocardial blood flow in animals to evaluate new treatment strategies or to understand underlying disease is also of great interest but raises some challenges. Animals, which have been anesthetized during PET acquisition, might react differently to used stress medications, and therefore difficulties might exist while evaluating the resulting PET images using standard software packages from commercial vendors optimized for human hearts. Furthermore propofol, used for anesthesia, can influence myocardial perfusion and coronary flow reserve due to its vasorelaxant effect, and interactions might exist between propofol and used stress agents, potentially affecting the result of the examination. We present cardiac (82)Rb-PET studies performed in propofol-anesthetized minipigs with normal and infarcted myocardium stressed with both adenosine and dipyridamole. Despite the mentioned challenges, we were able to trace the small minipig heart with software designed for human cardiac PET and to achieve blood flow measurements comparable with results in humans with both adenosine and dipyridamole. We found dipyridamole to be a superior stress agent for this experimental setup. Finally, we were able to clearly identify the myocardial perfusion defect after an induced myocardial infarction. PMID:26931633

  2. Myocardial perfusion echocardiography and coronary microvascular dysfunction

    PubMed Central

    Barletta, Giuseppe; Del Bene, Maria Riccarda

    2015-01-01

    Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary microcirculation. No current diagnostic technique allows direct visualization of coronary microcirculation, but functional assessments of this circulation are possible. This represents a challenge in cardiology. Myocardial contrast echocardiography (MCE) was a breakthrough in echocardiography several years ago that claimed the capability to detect myocardial perfusion abnormalities and quantify coronary blood flow. Research demonstrated that the integration of quantitative MCE and fractional flow reserve improved the definition of ischemic burden and the relative contribution of collaterals in non-critical coronary stenosis. MCE identified no-reflow and low-flow within and around myocardial infarction, respectively, and predicted the potential functional recovery of stunned myocardium using appropriate interventions. MCE exhibited diagnostic performances that were comparable to positron emission tomography in microvascular reserve and microvascular dysfunction in angina patients. Overall, MCE improved echocardiographic evaluations of ischemic heart disease in daily clinical practice, but the approval of regulatory authorities is lacking. PMID:26730291

  3. Myocardial perfusion echocardiography and coronary microvascular dysfunction.

    PubMed

    Barletta, Giuseppe; Del Bene, Maria Riccarda

    2015-12-26

    Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary microcirculation. No current diagnostic technique allows direct visualization of coronary microcirculation, but functional assessments of this circulation are possible. This represents a challenge in cardiology. Myocardial contrast echocardiography (MCE) was a breakthrough in echocardiography several years ago that claimed the capability to detect myocardial perfusion abnormalities and quantify coronary blood flow. Research demonstrated that the integration of quantitative MCE and fractional flow reserve improved the definition of ischemic burden and the relative contribution of collaterals in non-critical coronary stenosis. MCE identified no-reflow and low-flow within and around myocardial infarction, respectively, and predicted the potential functional recovery of stunned myocardium using appropriate interventions. MCE exhibited diagnostic performances that were comparable to positron emission tomography in microvascular reserve and microvascular dysfunction in angina patients. Overall, MCE improved echocardiographic evaluations of ischemic heart disease in daily clinical practice, but the approval of regulatory authorities is lacking. PMID:26730291

  4. High Concordance Between Mental Stress–Induced and Adenosine-Induced Myocardial Ischemia Assessed Using SPECT in Heart Failure Patients: Hemodynamic and Biomarker Correlates

    PubMed Central

    Wawrzyniak, Andrew J.; Dilsizian, Vasken; Krantz, David S.; Harris, Kristie M.; Smith, Mark F.; Shankovich, Anthony; Whittaker, Kerry S.; Rodriguez, Gabriel A.; Gottdiener, John; Li, Shuying; Kop, Willem; Gottlieb, Stephen S.

    2016-01-01

    Mental stress can trigger myocardial ischemia, but the prevalence of mental stress–induced ischemia in congestive heart failure (CHF) patients is unknown. We characterized mental stress–induced and adenosine-induced changes in myocardial perfusion and neurohormonal activation in CHF patients with reduced left-ventricular function using SPECT to precisely quantify segment-level myocardial perfusion. Methods Thirty-four coronary artery disease patients (mean age ± SD, 62 ± 10 y) with CHF longer than 3 mo and ejection fraction less than 40% underwent both adenosine and mental stress myocardial perfusion SPECT on consecutive days. Mental stress consisted of anger recall (anger-provoking speech) followed by subtraction of serial sevens. The presence and extent of myocardial ischemia was quantified using the conventional 17-segment model. Results Sixty-eight percent of patients had 1 ischemic segment or more during mental stress and 81% during adenosine. On segment-by-segment analysis, perfusion with mental stress and adenosine were highly correlated. No significant differences were found between any 2 time points for B-type natriuretic peptide, tumor necrosis factor-α, IL-1b, troponin, vascular endothelin growth factor, IL-17a, matrix metallopeptidase-9, or C-reactive protein. However, endothelin-1 and IL-6 increased, and IL-10 decreased, between the stressor and 30 min after stress. Left-ventricular end diastolic dimension was 179 ± 65 mL at rest and increased to 217 ± 71 after mental stress and 229 ± 86 after adenosine (P < 0.01 for both). Resting end systolic volume was 129 ± 60 mL at rest and increased to 158 ± 66 after mental stress (P < 0.05) and 171 ± 87 after adenosine (P < 0.07), with no significant differences between adenosine and mental stress. Ejection fraction was 30 ± 12 at baseline, 29 ± 11 with mental stress, and 28 ± 10 with adenosine (P = not significant). Conclusion There was high concordance between ischemic perfusion defects induced

  5. Specificity of synergistic coronary flow enhancement by adenosine and pulsatile perfusion in the dog.

    PubMed

    Pagliaro, P; Senzaki, H; Paolocci, N; Isoda, T; Sunagawa, G; Recchia, F A; Kass, D A

    1999-10-01

    1. Coronary flow elevation from enhanced perfusion pulsatility is synergistically amplified by adenosine. This study determined the specificity of this interaction and its potential mechanisms. 2. Mean and phasic coronary flow responses to increasing pulsatile perfusion were assessed in anaesthetized dogs, with the anterior descending coronary artery servoperfused to regulate real-time physiological flow pulsatility at constant mean pressure. Pulsatility was varied between 40 and 100 mmHg. Hearts ejected into the native aorta whilst maintaining stable loading. 3. Increasing pulsatility elevated mean coronary flow +11.5 +/- 1.7 % under basal conditions. Co-infusion of adenosine sufficient to raise baseline flow 66 % markedly amplified this pulsatile perfusion response (+82. 6 +/- 14.3 % increase in mean flow above adenosine baseline), due to a leftward shift of the adenosine-coronary flow response curve at higher pulsatility. Flow augmentation with pulsatility was not linked to higher regional oxygen consumption, supporting direct rather than metabolically driven mechanisms. 4. Neither bradykinin, acetylcholine nor verapamil reproduced the synergistic amplification of mean flow by adenosine and higher pulsatility, despite being administered at doses matching basal flow change with adenosine. 5. ATP-sensitive potassium (KATP) activation (pinacidil) amplified the pulse-flow response 3-fold, although this remained significantly less than with adenosine. Co-administration of the phospholipase A2 inhibitor quinacrine virtually eliminated adenosine-induced vasodilatation, yet synergistic interaction between adenosine and pulse perfusion persisted, albeit at a reduced level. 6. Thus, adenosine and perfusion pulsatility specifically interact to enhance coronary flow. This synergy is partially explained by KATP agonist action and additional non-flow-dependent mechanisms, and may be important for modulating flow reserve during exercise or other high output states where

  6. Regional Myocardial Perfusion Rates in Patients with Coronary Artery Disease

    PubMed Central

    Cannon, Paul J.; Dell, Ralph B.; Dwyer, Edward M.

    1972-01-01

    Regional myocardial perfusion rates were estimated from the myocardial washout of 133Xenon in 24 patients with heart disease whose coronary arteriograms were abnormal and 17 similar subjects whose coronary arteriograms were judged to be normal. Disappearance rates of 133Xe from multiple areas of the heart were monitored externally with a multiple-crystal scintillation camera after the isotope had been injected into a coronary artery and local myocardial perfusion rates were calculated by the Kety formula. The mean myocardial perfusion rates in the left ventricle exceeded those in the right ventricle or atrial regions in subjects without demonstrable coronary artery disease. In this group there was a significant lack of homogeneity of local perfusion rates in left ventricular myocardium; the mean coefficient of variation of left ventricular local perfusion rates was 15.8%. In the patients with radiographically demonstrable coronary artery disease, a variety of myocardial perfusion patterns were observed. Local capillary blood flow rates were depressed throughout the myocardium of patients with diffuse coronary disease but were subnormal only in discrete myocardial regions of others with localized occlusive disease. Local myocardial perfusion rates were similar to those found in the group with normal coronary arteriograms in patients with slight degrees of coronary disease and in those areas of myocardium distal to marked coronary constrictions or occlusions which were well supplied by collateral vessels. In subjects with right coronary disease, the mean right ventricular perfusion rates were significantly subnormal; in seven subjects of this group perfusion of the inferior left ventricle by a dominant right coronary artery was absent or depressed. The average mean left ventricular perfusion rate of 12 subjects with significant disease of two or more branches of the left coronary artery was significantly lower than that of the group with normal left coronary

  7. SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

    PubMed

    Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

    2016-01-01

    Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions. PMID:26053731

  8. Effects of adenosine, adenosine triphosphate and structural analogues on glucagon secretion from the perfused pancreas of rat in vitro.

    PubMed Central

    Chapal, J.; Loubatières-Mariani, M. M.; Roye, M.; Zerbib, A.

    1984-01-01

    The effects of adenosine, adenosine triphosphate (ATP) and structural analogues have been studied on glucagon secretion from the isolated perfused pancreas of the rat in the presence of glucose (2.8 mM). Adenosine induced a transient increase of glucagon secretion. This effect was concentration-dependent in the range of 0.165 to 165 microM. ATP also induced an increase, but the effect was no greater at 165 microM than at 16.5 microM. 2-Chloroadenosine, an analogue more resistant to metabolism or uptake systems than adenosine, was more effective. Among the three structural analogues of ATP or ADP studied, beta, gamma-methylene ATP which can be hydrolyzed into AMP and adenosine had an effect similar to adenosine or ATP at the same concentrations (1.65 and 16.5 microM); in contrast alpha, beta-methylene ATP and alpha, beta-methylene ADP (resistant to hydrolysis into AMP and adenosine) were ineffective. Theophylline (50 microM) a specific blocker of the adenosine receptor, suppressed the glucagon peak induced by adenosine, 2-chloroadenosine, ATP and beta, gamma-methylene ATP (1.65 microM). An inhibitor of 5' nucleotidase, alpha, beta-methylene ADP (16.5 microM), reduced the glucagon increase induced by ATP and did not affect the response to adenosine (1.65 microM). These results support the hypothesis of adenosine receptors (P1-purinoceptors) on the pancreatic glucagon secretory cells and indicate that ATP acts after hydrolysis to adenosine. PMID:6097328

  9. 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.

  10. Myocardial perfusion with rubidium-82. III. Theory relating severity of coronary stenosis to perfusion deficit

    SciTech Connect

    Mullani, N.A.

    1984-11-01

    The relation between the quantitative perfusion deficit, as measured by emission computerized tomography, and the severity of coronary artery stenosis is important for the noninvasive clinical evaluation of coronary artery disease in man. Positron emission tomography allows direct noninvasive measurement of myocardial perfusion and quantification of the size of the perfusion defect. Given this important imformation, a mathematical model has been derived to gauge the severity of a coronary stenosis from quantitative perfusion measurements in the normal and poststenotic regions of the heart. The theoretical basis is presented for relating regional myocardial perfusion and regional perfusion resistance to total, coronary blood flow and resistance at normal resting flow and during maximal coronary vasodilation. The concept of perfusion reserve is presented as a clinical measure of the severity of a stenosis.

  11. Effect of venous injection site on accuracy of fast computed tomography (CT) estimation of myocardial perfusion

    SciTech Connect

    Bell, M.R.; Rumberger, J.A.; Lerman, L.O.; Behrenbeck, T.; Sheedy, P.F.; Ritman, E.L. )

    1990-02-26

    Measurement of myocardial perfusion with fast CT, using venous injections of contrast, underestimates high flow rates. Accounting for intramyocardial blood volume improves the accuracy of such measurements but the additional influence of different contrast injection sites is unknown. To examine this, eight closed chest anesthetized dogs (18-24 kg) underwent fast CT studies of regional myocardial perfusion which were compared to microspheres (M). Dilute iohexol (0.5 mL/kg) was injected over 2.5 seconds, via, in turn, the pulmonary artery (PA), proximal inferior vena cava (IVC) and femoral vein (FV) during CT scans performed at rest and after vasodilation with adenosine (M flow range: 52-399 mL/100 g/minute). Correlations made with M were not significantly different for PA vs IVC (n = 24), PA vs FV (n = 22) and IVC vs FV (n = 44). To determine the relative influence of injection site on accuracy of measurements above normal flow rates (> 150mL/100g/minute), CT flow (mL/100g/minute; mean {+-}SD) was compared to M. Thus, at normal flow, some CT overestimation of myocardial perfusion occurred with PA injections but FV or IVC injections provided for accurate measurements. At higher flow rates only PA and IVC injections enabled accurate CT measurements of perfusion. This may be related to differing transit kinetics of the input bolus of contrast.

  12. Multi-modality imaging for the assessment of myocardial perfusion with emphasis on stress perfusion CT and MR imaging.

    PubMed

    Ko, Sung Min; Hwang, Hweung Kon; Kim, Sung Mok; Cho, Ihn Ho

    2015-06-01

    High-quality and non-invasive diagnostic tools for assessing myocardial ischemia are necessary for therapeutic decisions regarding coronary artery disease. Myocardial perfusion has been studied using myocardial contrast echo perfusion, single-photon emission computed tomography, positron emission tomography, cardiovascular magnetic resonance, and, more recently, computed tomography. The addition of coronary computed tomography angiography to myocardial perfusion imaging improves the specificity and overall diagnostic accuracy of detecting the hemodynamic significance of coronary artery stenosis. This study reviews the benefits, limitations, and imaging findings of various imaging modalities for assessing myocardial perfusion, with particular emphasis on stress perfusion computed tomography and cardiovascular magnetic resonance imaging. PMID:25809387

  13. Static and dynamic assessment of myocardial perfusion by computed tomography.

    PubMed

    Danad, Ibrahim; Szymonifka, Jackie; Schulman-Marcus, Joshua; Min, James K

    2016-08-01

    Recent developments in computed tomography (CT) technology have fulfilled the prerequisites for the clinical application of myocardial CT perfusion (CTP) imaging. The evaluation of myocardial perfusion by CT can be achieved by static or dynamic scan acquisitions. Although both approaches have proved clinically feasible, substantial barriers need to be overcome before its routine clinical application. The current review provides an outline of the current status of CTP imaging and also focuses on disparities between static and dynamic CTPs for the evaluation of myocardial blood flow. PMID:27013250

  14. New Trends in Radionuclide Myocardial Perfusion Imaging

    PubMed Central

    Hung, Guang-Uei; Wang, Yuh-Feng; Su, Hung-Yi; Hsieh, Te-Chun; Ko, Chi-Lun; Yen, Ruoh-Fang

    2016-01-01

    Radionuclide myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) has been widely used clinically as one of the major functional imaging modalities for patients with coronary artery disease (CAD) for decades. Ample evidence has supported the use of MPI as a useful and important tool in the diagnosis, risk stratification and treatment planning for CAD. Although popular in the United States, MPI has become the most frequently used imaging modality among all nuclear medicine tests in Taiwan. However, it should be acknowledged that MPI SPECT does have its limitations. These include false-positive results due to certain artifacts, false-negative due to balanced ischemia, complexity and adverse reaction arising from current pharmacological stressors, time consuming nature of the imaging procedure, no blood flow quantitation and relatively high radiation exposure. The purpose of this article was to review the recent trends in nuclear cardiology, including the utilization of positron emission tomography (PET) for MPI, new stressor, new SPECT camera with higher resolution and higher sensitivity, dynamic SPECT protocol for blood flow quantitation, new software of phase analysis for evaluation of LV dyssynchrony, and measures utilized for reducing radiation exposure of MPI. PMID:27122946

  15. A relative quantitative assessment of myocardial perfusion by first-pass technique: animal study

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Zhang, Zhang; Yu, Xuefang; Zhou, Kenneth J.

    2015-03-01

    The purpose of this study is to quantitatively assess the myocardial perfusion by first-pass technique in swine model. Numerous techniques based on the analysis of Computed Tomography (CT) Hounsfield Unit (HU) density have emerged. Although these methods proposed to be able to assess haemodynamically significant coronary artery stenosis, their limitations are noticed. There are still needs to develop some new techniques. Experiments were performed upon five (5) closed-chest swine. Balloon catheters were placed into the coronary artery to simulate different degrees of luminal stenosis. Myocardial Blood Flow (MBF) was measured using color microsphere technique. Fractional Flow Reserve (FFR) was measured using pressure wire. CT examinations were performed twice during First-pass phase under adenosine-stress condition. CT HU Density (HUDCT) and CT HU Density Ratio (HUDRCT) were calculated using the acquired CT images. Our study presents that HUDRCT shows a good (y=0.07245+0.09963x, r2=0.898) correlation with MBF and FFR. In receiver operating characteristic (ROC) curve analyses, HUDRCT provides excellent diagnostic performance for the detection of significant ischemia during adenosine-stress as defined by FFR indicated by the value of Area Under the Curve (AUC) of 0.927. HUDRCT has the potential to be developed as a useful indicator of quantitative assessment of myocardial perfusion.

  16. Nifedipine and thallium-201 myocardial perfusion in progressive systemic sclerosis

    SciTech Connect

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

    1986-05-29

    Heart disease in patients with progressive systemic sclerosis may be due in part to myocardial ischemia caused by a disturbance of the coronary microcirculation. To determine whether abnormalities of myocardial perfusion in this disorder are potentially reversible, we evaluated the effect of the coronary vasodilator nifedipine on myocardial perfusion assessed by thallium-201 scanning in 20 patients. Thallium-201 single-photon-emission computerized tomography was performed under control conditions and 90 minutes after 20 mg of oral nifedipine. The mean (+/- SD) number of left ventricular segments with perfusion defects decreased from 5.3 +/- 2.0 to 3.3 +/- 2.2 after nifedipine (P = 0.0003). Perfusion abnormalities were quantified by a perfusion score (0 to 2.0) assigned to each left ventricular segment and by a global perfusion score (0 to 18) for the entire left ventricle. The mean perfusion score in segments with resting defects increased from 0.97 +/- 0.24 to 1.26 +/- 0.44 after nifedipine (P less than 0.00001). The mean global perfusion score increased from 11.2 +/- 1.7 to 12.8 +/- 2.4 after nifedipine (P = 0.003). The global perfusion score increased by at least 2.0 in 10 patients and decreased by at least 2.0 in only 1. These observations reveal short-term improvement in thallium-201 myocardial perfusion with nifedipine in patients with progressive systemic sclerosis. The results are consistent with a potentially reversible abnormality of coronary vasomotion in this disorder, but the long-term therapeutic effects of nifedipine remain to be determined.

  17. Radionuclide Tracers for Myocardial Perfusion Imaging and Blood Flow Quantification.

    PubMed

    deKemp, Robert A; Renaud, Jennifer M; Klein, Ran; Beanlands, Rob S B

    2016-02-01

    Myocardial perfusion imaging is performed most commonly using Tc-99m-sestamibi or tetrofosmin SPECT as well as Rb-82-rubidium or N-13-ammonia PET. Diseased-to-normal tissue contrast is determined by the tracer retention fraction, which decreases nonlinearly with flow. Reduced tissue perfusion results in reduced tracer retention, but the severity of perfusion defects is typically underestimated by 20% to 40%. Compared to SPECT, retention of the PET tracers is more linearly related to flow, and therefore, the perfusion defects are measured more accurately using N-13-ammonia or Rb-82. PMID:26590778

  18. Myocardial Perfusion Scintigraphy: Techniques, Interpretation, Indications and Reporting

    PubMed Central

    Fathala, Ahmed

    2011-01-01

    Myocardial perfusion single photon emission-computed tomography (MPS) has been one of the most important and common non-invasive diagnostic cardiac test. Gated MPS provides simultaneous assessment of myocardial perfusion and function with only one study. With appropriate attention to the MPS techniques, appropriate clinical utilization and effective reporting, gated MPS will remain a useful diagnostic test for many years to come. The aim of this article is to review the basic techniques of MPS, a simplified systematic approach for study interpretation, current clinical indications and reporting. After reading this article the reader should develop an understanding of the techniques, interpretation, current clinical indications and reporting of MPS studies. PMID:22048510

  19. Simultaneous technetium-99m MIBI angiography and myocardial perfusion imaging

    SciTech Connect

    Baillet, G.Y.; Mena, I.G.; Kuperus, J.H.; Robertson, J.M.; French, W.J.

    1989-01-01

    Resting first-pass radionuclide angiography (FPRNA) was performed with the myocardial perfusion agent technetium-99m MIBI. In 27 patients, it was compared with technetium-99m diethylenetriamine pentaacetic acid FPRNA. A significant correlation was present in left (r = 0.93, p less than 0.001) as well as right (r = 0.92, p less than 0.001) ventricular ejection fraction measured with both radiopharmaceuticals. In 13 patients, MIBI derived segmental wall motion was compared with contrast ventriculography. A high correlation was present (p less than 0.001), and qualitative agreement was found in 38/52 segments. In 19 patients with myocardial infarction a significant correlation was present between MIBI segmental wall motion and perfusion scores (p less than 0.001). In ten patients with a history of myocardial infarction, 18 myocardial segments demonstrated diseased coronary vessels and impaired wall motion at contrast angiography. These segments were all identified by the MIBI wall motion and perfusion study. We conclude that MIBI is a promising agent for simultaneous evaluation of cardiac function and myocardial perfusion at rest.

  20. 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. PMID:26774540

  1. Adenosine as an Adjunct Therapy in ST Elevation Myocardial Infarction Patients: Myth or Truth?

    PubMed

    Kassimis, George; Davlouros, Periklis; Patel, Niket; De Maria, Gianluigi; Kallistratos, Manolis S; Kharbanda, Rajesh K; Manolis, Athanasios J; Alexopoulos, Dimitrios; Banning, Adrian P

    2015-10-01

    Early reperfusion represents the key strategy in ST elevation myocardial infarction. However, reperfusion may induce myocardial damage due to the reperfusion myocardial injury, compromising the full potential of reperfusion therapy and accounting for unfavourable results in high risk patients. Adenosine seems to attenuate ischemia reperfusion injury, and thus represents a promising therapeutic option for treating such patients. However, previous randomized clinical trials have collectively failed to demonstrate whether adenosine can effectively reduce measures of myocardial injury and improve clinical outcome, despite its good basic evidence. The failure of such trials to show a real beneficial action may be in part related to specific factors other than adenosine's clinical efficacy. The purpose of this review is to explain the rationale for the use of adenosine as an adjunctive pharmacological cardio-protective agent following reperfusion of the ischemic myocardium, to address the weakness of previous trials and to summarize the current state of knowledge regarding the effect of adenosine administration on reperfusion myocardial injury in patients with myocardial infarction. Although some preclinical and clinical studies point towards the beneficial role of adenosine in the prevention and treatment of no-reflow phenomenon in myocardial infarction, many unanswered questions still remain, including the optimal clinical indication, mode, dosage, duration and timing of application, and the exact mechanisms leading to potential benefits. Clarifying these issues will depend on further properly designed, adequately powered and well conducted clinical trials, which will probably provide us with the definite answers. PMID:26150100

  2. Regadenoson and adenosine are equivalent vasodilators and are superior than dipyridamole- a study of first pass quantitative perfusion cardiovascular magnetic resonance

    PubMed Central

    2013-01-01

    Background Regadenoson, dipyridamole and adenosine are commonly used vasodilators in myocardial perfusion imaging for the detection of obstructive coronary artery disease. There are few comparative studies of the vasodilator properties of regadenoson, adenosine and dipyridamole in humans. The specific aim of this study was to determine the relative potency of these three vasodilators by quantifying stress and rest myocardial perfusion in humans using cardiovascular magnetic resonance (CMR). Methods Fifteen healthy normal volunteers, with Framingham score less than 1% underwent vasodilator stress testing with regadenoson (400 μg bolus), dipyridamole (0.56 mg/kg) and adenosine (140 μg /kg/min) on separate days. Rest perfusion imaging was performed initially. Twenty minutes later, stress imaging was performed at peak vasodilation, i.e. 70 seconds after regadenoson, 4 minutes after dipyridamole infusion and between 3–4 minutes of the adenosine infusion. Myocardial blood flow (MBF) in ml/min/g and myocardial perfusion reserve (MPR) were quantified using a fully quantitative model constrained deconvolution. Results Regadenoson produced higher stress MBF than dipyridamole and adenosine (3.58 ± 0.58 vs. 2.81 ± 0.67 vs. 2.78 ± 0.61 ml/min/g, p = 0.0009 and p = 0.0008 respectively). Regadenoson had a much higher heart rate response than adenosine and dipyridamole respectively (95 ± 11 vs. 76 ± 13 vs. 86 ± 12 beats/ minute) When stress MBF was adjusted for heart rate, there were no differences between regadenoson and adenosine (37.8 ± 6 vs. 36.6 ± 4 μl/sec/g, p = NS), but differences between regadenoson and dipyridamole persisted (37.8 ± 6 vs. 32.6 ± 5 μl/sec/g, p = 0.03). The unadjusted MPR was higher with regadenoson (3.11 ± 0.63) when compared with adenosine (2.7 ± 0.61, p = 0.02) and when compared with dipyridamole (2.61 ± 0.57, p = 0.04). Similar to stress MBF, these differences in MPR between regadenoson and adenosine were abolished when adjusted

  3. 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.

  4. Determination of regional myocardial perfusion by x-ray fluorescence.

    PubMed

    Palmer, B M; McInerney, J J

    1990-05-01

    Validation studies were performed to demonstrate the effectiveness of an x-ray induced fluorescence system in quantitating regional myocardial perfusion in vivo. In a series of 13 open-chested canines, x-ray induced fluorescence was used to simultaneously monitor iodine concentration transients which arose in the left ventricular lumen and in the myocardium after the intravenous injection of an iodinated flow tracer. Deconvolution of the recorded transients produced a transfer function from which the mean transit time for the tracer to travel between the left ventricular lumen and the myocardium was calculated. Measurements of regional myocardial perfusion (Q) made by radioactive microspheres were compared with the reciprocals of the mean transit times (MTT-1) and gave a linear correlation (n = 38): MTT-1 = 0.033 + 0.069 Q, r = 0.71. Comparison of the percent change in perfusion (dQ) relative to a control study for each dog with the percent change in the respective reciprocals of the mean transit times (dMTT-1) produced a linear correlation coefficient of r = 0.88 for the regression line dMTT-1 = 0.46 dQ - 10.7. The x-ray induced fluorescence system may provide a minimally invasive means for monitoring iodine concentration transients and determining relative, if not absolute, measures of regional myocardial perfusion. PMID:2345078

  5. 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.

  6. 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.

  7. Myocardial perfusion abnormalities in asymptomatic patients with systemic lupus erythematosus

    SciTech Connect

    Hosenpud, J.D.; Montanaro, A.; Hart, M.V.; Haines, J.E.; Specht, H.D.; Bennett, R.M.; Kloster, F.E.

    1984-08-01

    Accelerated coronary artery disease and myocardial infarction in young patients with systemic lupus erythematosus is well documented; however, the prevalence of coronary involvement is unknown. Accordingly, 26 patients with systemic lupus were selected irrespective of previous cardiac history to undergo exercise thallium-201 cardiac scintigraphy. Segmental perfusion abnormalities were present in 10 of the 26 studies (38.5 percent). Five patients had reversible defects suggesting ischemia, four patients had persistent defects consistent with scar, and one patient had both reversible and persistent defects in two areas. There was no correlation between positive thallium results and duration of disease, amount of corticosteroid treatment, major organ system involvement or age. Only a history of pericarditis appeared to be associated with positive thallium-201 results (p less than 0.05). It is concluded that segmental myocardial perfusion abnormalities are common in patients with systemic lupus erythematosus. Whether this reflects large-vessel coronary disease or small-vessel abnormalities remains to be determined.

  8. In-vivo regional myocardial perfusion measurements in a porcine model by ECG-gated multislice computed tomography

    NASA Astrophysics Data System (ADS)

    Stantz, Keith M.; Liang, Yun; Meyer, Cristopher A.; Teague, Shawn; Stecker, Michael; Hutchins, Gary; McLennan, Gordon; Persohn, Scott

    2003-05-01

    Purpose: To evaluate whether functional multi-slice computed tomography (MSCT) can identify regional areas of normally perfused and ischemic myocardium in a porcine model. Material and Methods: Three out bred pigs, two of which had ameroids surgically implanted to constrict flow within the LAD and LCx coronary arteries, were injected with 25 mL of iopromide (Isovue) at a rate of 5 mL/second via the femoral or jugular vein. Sixty axial scans along the short axis of the heart was acquired on a 16-slice CT scanner (Philips MX8000-IDT) triggered at end-diastole of the cardiac cycle and acquiring an image within 270 msec. A second series of scans were taken after an intravenous injection of a vasodilator, 150 μg/kg/min of adenosine. ROIs were drawn around the myocardial tissue and the resulting time-density curves were used to extract perfusion values. Results: Determination of the myocardial perfusion and fractional blood volume implementing three different perfusion models. A 5-point averaging or 'smoothing' algorithm was employed to effectively filter the data due to its noisy nature. The (preliminary) average perfusion and fractional blood volume values over selected axial slices for the pig without an artificially induced stenosis were measured to be 84 +/- 22 mL/min/100g-tissue and 0.17 +/- 0.04 mL/g-tissue, the former is consistent with PET scan and EBCT results. The pig with a stenosis in the left LAD coronary artery showed a reduced global perfusion value -- 45 mL/min/100g-tissue. Correlations in regional perfusion values relative to the stenosis were weak. During the infusion of adenosine, averaged perfusion values for the three subjects increased by 46 (+/-45) percent, comparable to increases measured with PET. Conclusion: Quantifying global perfusion values using MDCT appear encouraging. Future work will focus resolving the systematic effects from noise due to signal fluctuation from the porcine tachyardia (80-93 BPM) and provide a more robust measurement

  9. The prognostic value of non-perfusion variables obtained during vasodilator stress myocardial perfusion imaging.

    PubMed

    Bajaj, Navkaranbir S; Singh, Siddharth; Farag, Ayman; El-Hajj, Stephanie; Heo, Jack; Iskandrian, Ami E; Hage, Fadi G

    2016-06-01

    Myocardial perfusion imaging (MPI) is an established diagnostic test that provides useful prognostic data in patients with known or suspected coronary artery disease. In more than half of the patients referred for stress testing, vasodilator stress is used in lieu of exercise. Unlike exercise, vasodilator stress does not provide information on exercise and functional capacity, heart rate recovery, and chronotropy, and ECG changes are less frequent. These non-perfusion data provide important prognostic and patient management information. Further, event rates in patients undergoing vasodilator MPI are higher than in those undergoing exercise MPI and even in those with normal images probably due to higher pretest risk. However, there are a number of non-perfusion variables that are obtained during vasodilator stress testing, which have prognostic relevance but their use has not been well emphasized. The purpose of this review is to summarize the prognostic values of these non-perfusion data obtained during vasodilator MPI. PMID:26940574

  10. Myocardial Perfusion and Function Are Distinctly Altered by Sevoflurane Anesthesia in Diet-Induced Prediabetic Rats.

    PubMed

    van den Brom, Charissa E; Boly, Chantal A; Bulte, Carolien S E; van den Akker, Rob F P; Kwekkeboom, Rick F J; Loer, Stephan A; Boer, Christa; Bouwman, R Arthur

    2016-01-01

    Preservation of myocardial perfusion during surgery is particularly important in patients with increased risk for perioperative complications, such as diabetes. Volatile anesthetics, like sevoflurane, have cardiodepressive effects and may aggravate cardiovascular complications. We investigated the effect of sevoflurane on myocardial perfusion and function in prediabetic rats. Rats were fed a western diet (WD; n = 18) or control diet (CD; n = 18) for 8 weeks and underwent (contrast) echocardiography to determine perfusion and function during baseline and sevoflurane exposure. Myocardial perfusion was estimated based on the product of microvascular filling velocity and blood volume. WD-feeding resulted in a prediabetic phenotype characterized by obesity, hyperinsulinemia, hyperlipidemia, glucose intolerance, and hyperglycemia. At baseline, WD-feeding impaired myocardial perfusion and systolic function compared to CD-feeding. Exposure of healthy rats to sevoflurane increased the microvascular filling velocity without altering myocardial perfusion but impaired systolic function. In prediabetic rats, sevoflurane did also not affect myocardial perfusion; however, it further impaired systolic function. Diet-induced prediabetes is associated with impaired myocardial perfusion and function in rats. While sevoflurane further impaired systolic function, it did not affect myocardial perfusion in prediabetic rats. Our findings suggest that sevoflurane anesthesia leads to uncoupling of myocardial perfusion and function, irrespective of the metabolic state. PMID:26824042

  11. Myocardial Perfusion and Function Are Distinctly Altered by Sevoflurane Anesthesia in Diet-Induced Prediabetic Rats

    PubMed Central

    van den Brom, Charissa E.; Boly, Chantal A.; Bulte, Carolien S. E.; van den Akker, Rob F. P.; Kwekkeboom, Rick F. J.; Loer, Stephan A.; Boer, Christa; Bouwman, R. Arthur

    2016-01-01

    Preservation of myocardial perfusion during surgery is particularly important in patients with increased risk for perioperative complications, such as diabetes. Volatile anesthetics, like sevoflurane, have cardiodepressive effects and may aggravate cardiovascular complications. We investigated the effect of sevoflurane on myocardial perfusion and function in prediabetic rats. Rats were fed a western diet (WD; n = 18) or control diet (CD; n = 18) for 8 weeks and underwent (contrast) echocardiography to determine perfusion and function during baseline and sevoflurane exposure. Myocardial perfusion was estimated based on the product of microvascular filling velocity and blood volume. WD-feeding resulted in a prediabetic phenotype characterized by obesity, hyperinsulinemia, hyperlipidemia, glucose intolerance, and hyperglycemia. At baseline, WD-feeding impaired myocardial perfusion and systolic function compared to CD-feeding. Exposure of healthy rats to sevoflurane increased the microvascular filling velocity without altering myocardial perfusion but impaired systolic function. In prediabetic rats, sevoflurane did also not affect myocardial perfusion; however, it further impaired systolic function. Diet-induced prediabetes is associated with impaired myocardial perfusion and function in rats. While sevoflurane further impaired systolic function, it did not affect myocardial perfusion in prediabetic rats. Our findings suggest that sevoflurane anesthesia leads to uncoupling of myocardial perfusion and function, irrespective of the metabolic state. PMID:26824042

  12. Radionuclide imaging of myocardial perfusion and viability in assessment of acute myocardial infarction

    SciTech Connect

    Berman, D.S.; Kiat, H.; Maddahi, J.; Shah, P.K.

    1989-07-18

    Technical advances in radionuclide imaging have important implications for the management of patients with acute myocardial infarction. Single-photon emission computerized tomography with thallium 201 (TI-201) offers greater accuracy than planar imaging in detecting, localizing and sizing myocardial perfusion defects. Use of single-photon emission computerized tomography with TI-201 should allow for a more accurate assessment of prognosis after myocardial infarction. A new radiopharmaceutical, technetium 99-m methoxyisobutyl isonitrile, provides a number of advantages over TI-201, including higher quality images, lack of redistribution, and the ability to assess first-pass ventricular function. Applications of TI-201 and technetium 99-m methoxyisobutyl isonitrile include assessment of arterial patency and myocardial salvage immediately after thrombolytic therapy, detection of resting ischemia after thrombolytic therapy, targeting of subsets of patients for further intervention, and predischarge assessment to predict the future course of patients after an acute myocardial infarction.

  13. Myocardial perfusion imaging study of CO(2)-induced panic attack.

    PubMed

    Soares-Filho, Gastão L F; Machado, Sergio; Arias-Carrión, Oscar; Santulli, Gaetano; Mesquita, Claudio T; Cosci, Fiammetta; Silva, Adriana C; Nardi, Antonio E

    2014-01-15

    Chest pain is often seen alongside with panic attacks. Moreover, panic disorder has been suggested as a risk factor for cardiovascular disease and even a trigger for acute coronary syndrome. Patients with coronary artery disease may have myocardial ischemia in response to mental stress, in which panic attack is a strong component, by an increase in coronary vasomotor tone or sympathetic hyperactivity setting off an increase in myocardial oxygen consumption. Indeed, coronary artery spasm was presumed to be present in cases of cardiac ischemia linked to panic disorder. These findings correlating panic disorder with coronary artery disease lead us to raise questions about the favorable prognosis of chest pain in panic attack. To investigate whether myocardial ischemia is the genesis of chest pain in panic attacks, we developed a myocardial perfusion study through research by myocardial scintigraphy in patients with panic attacks induced in the laboratory by inhalation of 35% carbon dioxide. In conclusion, from the data obtained, some hypotheses are discussed from the viewpoint of endothelial dysfunction and microvascular disease present in mental stress response. PMID:24188891

  14. Adenosine enhances myocardial glucose uptake only in the presence of insulin.

    PubMed

    Law, W R; McLane, M P

    1991-09-01

    Better understood in other tissues, the effects of adenosine on insulin-stimulated glucose uptake in the heart are poorly understood. Under pentobarbital anesthesia, we instrumented mongrel dogs to obtain general hemodynamics (blood pressure and heart rate), and arterial and coronary sinus blood samples for measuring oxygen and glucose concentrations. An electromagnetic blood flow probe around the circumflex coronary artery allowed determinations of blood flow, and calculation of substrate uptake by the heart (Fick principle). Somatostatin (SRIF) was infused intravenously (0.8 micrograms/kg/min) along with 0, 0.5, 1.0, 5.0, or 10 mU/kg/min regular insulin, and variable quantities of glucose to maintain euglycemia. Concomitant with the SRIF, insulin, and glucose infusions, adenosine was infused in logarithmically increasing rates (0, 0.01, 0.1, 1.0, 10 or 100 mumol/min) for 30 minutes each into the main left coronary arteries. Insulin infusions increased myocardial glucose uptake in a dose-dependent manner. The heart displayed exquisite sensitivity to insulin, with an ED50 of approximately 14 microU/mL (serum insulin). Adenosine infusions in the absence of insulin (SRIF infusion) increased coronary blood flow, but did not alter myocardial glucose uptake. In the presence of insulin, adenosine increased the maximal value for glucose uptake without changing sensitivity to insulin. These results indicate that adenosine enhances myocardial responsiveness to insulin, with respect to glucose uptake, independent of changes in blood flow. Since glucose can be used for anaerobic metabolism, and adenosine levels are known to increase under situations in which myocardial oxygenation is inadequate, these data have serious implications for conditions such as myocardial ischemia or hypoxia, when glycolytic substrate availability is vital. PMID:1680214

  15. Assessment of myocardial blood perfusion improved by CD151 in a pig myocardial infarction model

    PubMed Central

    Zuo, Hou-juan; Liu, Zheng-xiang; Liu, Xiao-chun; Yang, Jun; Liu, Tao; Wen, Sha; Wang, Dao-wen; Zhang, Xin

    2009-01-01

    Aim: To appraise the efficacy of CD151-induced myocardial therapeutic angiogenesis in a pig myocardial infarction model. Methods: CD151 and anti-CD151 were constructed into the recombinant adeno-associated virus (rAAV) vector. All 26 pigs were subjected to coronary artery ligation or no surgery. Eight weeks after coronary artery ligation, the expression of CD151 was measured by Western blot and immunostaining. Capillary density was evaluated using immunostaining for von Willebrand factor (vWF). 13N-labeled NH3 positron emission computed tomography ([13N]NH3 PET) was measured to assess regional myocardial perfusion and the defect area. Results: CD151 gene delivery could increase the expression of CD151 at protein level. Over-expression of CD151 increased the density of total capillaries in the ischemic myocardium, significantly improved the blood perfusion and reduced the defect area percentage. Conclusion: This study demonstrated that the rAAV-mediated CD151 gene delivery promoted efficient neovascularization and increased the blood perfusion after myocardial infarction in pigs. PMID:19079294

  16. Cardiac magnetic resonance imaging for myocardial perfusion and diastolic function—reference control values for women

    PubMed Central

    Bakir, May; Wei, Janet; Nelson, Michael D.; Mehta, Puja K.; Haftbaradaran, Afsaneh; Jones, Erika; Gill, Edward; Sharif, Behzad; Slomka, Piotr J.; Li, Debiao; Shufelt, Chrisandra L.; Minissian, Margo; Berman, Daniel S.; Bairey Merz, C. Noel

    2016-01-01

    Angina, heart failure with preserved ejection fraction (HFpEF) and coronary microvascular dysfunction (CMD) in the absence of obstructive coronary artery disease (CAD) are more common in women and are associated with adverse cardiovascular prognosis. Cardiac magnetic resonance imaging (CMRI) is established for assessment of left ventricular (LV) morphology and systolic function and is increasingly used to assess myocardial perfusion and diastolic function. Indeed, stress CMRI allows measurement of myocardial perfusion reserve index (MPRI) using semi-quantitative techniques, and quantification of LV volumetric filling patterns provides valuable insight into LV diastolic function. The utility of these two techniques remains limited, because reference control values for MPRI and LV diastolic function in asymptomatic middle-aged, women have not previously been established. To address this limitation, we recruited twenty women, without clinical cardiovascular disease or cardiovascular risk factors, with normal maximal Bruce protocol exercise treadmill testing. Subjects underwent CMRI (1.5 tesla) using a standardized protocol of adenosine stress and rest perfusion and LV cinematic imaging. Commercially available with automated CMRI segmentation was used for calculation of MPRI, LV filling profiles, and ejection fraction. Mean age was 54±9 years and mean body mass index was 25±4 kg/m3. The exercise treadmill testing results demonstrated a normotensive group with normal functional capacity and hemodynamic response. We report reference control values for semi-quantitative MPRI as well as measures of LV systolic and diastolic function including ejection fraction, stroke volume, peak filling rate (PFR), PFR adjusted for end-diastolic volume (EDV) and stroke volume, time to PFR, and EDV index. The data herein provide reference values for MPRI and diastolic function in a cohort of healthy, middle-aged of women. These reference values may be used for comparison with a variety

  17. Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris

    SciTech Connect

    Selwyn, A.P.; Forse, G.; Fox, K.; Jonathan, A.; Steiner, R.

    1981-07-01

    Fifty patients who presented with angina pectoris were studied to examine the disturbances of regional myocardial perfusion during stress. Each patient underwent 16-point precordial mapping of the ECG during an exercise test, and coronary and left ventricular angiography. Regional myocardial perfusion was assessed using an atrial pacing test and a short-lived radionuclide, krypton-81m. Eleven patients had negative exercise tests and uniform increases in myocardial activity of krypton-81m of 98 +/- 18.0% during pacing. Ten patients performed 30,000-43,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and increases in myocardial activity of krypton-81m to remote and jeopardized myocardium at the onset of pacing. However, further pacing produced a decrease in activity in the affected segment of 68.0 +/- 9.0% accompanied by ST-segment depression and angina. Twelve patients achieved 26,000-32,000 J in positive exercise tests and had significant coronary artery disease. Atrial pacing produced increased activity of krypton-81m to remote myocardium. The jeopardized segment at first showed no change and then a decrease in regional activity of krypton-81m (89.0 +/- 17%) accompanied by ST-segment depression and chest pain. Seventeen patients achieved only 7000-22,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and developed decreases in regional activity of krypton-81m to the affected segment of myocardium starting at the onset of atrial pacing and decreasing by 88 +/- 0 7.0% below control. We conclude that different patterns of disturbed myocardial distribution of krypton-81m are present during stress-induced ischemia in patients with coronary artery disease. There was a close temporal relationship between these disturbances and ST-segment depression.

  18. Approaches to reducing radiation dose from radionuclide myocardial perfusion imaging.

    PubMed

    Dorbala, Sharmila; Blankstein, Ron; Skali, Hicham; Park, Mi-Ae; Fantony, Jolene; Mauceri, Charles; Semer, James; Moore, Stephen C; Di Carli, Marcelo F

    2015-04-01

    Radionuclide myocardial perfusion imaging (MPI) plays a vital role in the evaluation and management of patients with coronary artery disease. However, because of a steep growth in MPI in the mid 2000s, concerns about inappropriate use of MPI and imaging-related radiation exposure increased. In response, the professional societies developed appropriate-use criteria for MPI. Simultaneously, novel technology, image-reconstruction software for traditional scanners, and dedicated cardiac scanners emerged and facilitated the performance of MPI with low-dose and ultra-low-dose radiotracers. This paper provides a practical approach to performing low-radiation-dose MPI using traditional and novel technologies. PMID:25766891

  19. Panic attack triggering myocardial ischemia documented by myocardial perfusion imaging study. A case report

    PubMed Central

    2012-01-01

    Background Chest pain, a key element in the investigation of coronary artery disease is often regarded as a benign prognosis when present in panic attacks. However, panic disorder has been suggested as an independent risk factor for long-term prognosis of cardiovascular diseases and a trigger of acute myocardial infarction. Objective Faced with the extreme importance in differentiate from ischemic to non-ischemic chest pain, we report a case of panic attack induced by inhalation of 35% carbon dioxide triggering myocardial ischemia, documented by myocardial perfusion imaging study. Discussion Panic attack is undoubtedly a strong component of mental stress. Patients with coronary artery disease may present myocardial ischemia in mental stress response by two ways: an increase in coronary vasomotor tone or a sympathetic hyperactivity leading to a rise in myocardial oxygen consumption. Coronary artery spasm was presumed to be present in cases of cardiac ischemia linked to panic disorder. Possibly the carbon dioxide challenge test could trigger myocardial ischemia by the same mechanisms. Conclusion The use of mental stress has been suggested as an alternative method for myocardial ischemia investigation. Based on translational medicine objectives the use of CO2 challenge followed by Sestamibi SPECT could be a useful method to allow improved application of research-based knowledge to the medical field, specifically at the interface of PD and cardiovascular disease. PMID:22999016

  20. Laser Doppler imaging of myocardial perfusion during coronary bypass surgery

    NASA Astrophysics Data System (ADS)

    Wardell, Karin; Hermansson, Ulf; Nilsson, Gert E.; Casimir-Ahn, Henrik

    2000-05-01

    Laser Doppler perfusion imaging has been used to assess the myocardium perfusion on the arrested heart during bypass surgery. Twenty-two patients undergoing coronary artery bypass grafting, including usage of the left internal thoracic artery, were included in the study. The anticipated perfusion increase following declamping of the internal thoracic artery was investigated by mapping areas at the size of 10 cm X 11 cm, (n equals 11) and 7 cm X 5 cm (n equals 11). The larger images allowed quantification of blood flow in different regions of the myocardium. The size of the affected area was 32.2 +/- 12.9 cm2 with a total increase of 3.17 +/- 0.75 a.u. (range 0 - 10 a.u.). Corresponding values for areas surrounding the vessels and areas defined as the larger vessels in the myocardium were 29.0 +/- 10.9 cm2 (2.85 +/- 0.57 a.u.) and 3.5 +/- 2.8 cm2 (6.78 +/- 0.18 a.u.). All subjects but two showed a substantial blood flow increase (> 2 a.u.) after release of the clamp. Six subjects had a total increase of at least 4 a.u. Correlation analysis between areas including various number of sites showed an r equals 0.91 (p < 0,0001) or better. In conclusion, laser Doppler perfusion imaging can easily be used intraoperatively in conjunction with bypass surgery. It enables immediate assessment of both the increase and spatial distribution of myocardial perfusion following declamping of an arterial graft.

  1. Reversible cold-induced abnormalities in myocardial perfusion and function in systemic sclerosis

    SciTech Connect

    Alexander, E.L.; Firestein, G.S.; Weiss, J.L.; Heuser, R.R.; Leitl, G.; Wagner, H.N. Jr.; Brinker, J.A.; Ciuffo, A.A.; Becker, L.C.

    1986-11-01

    The effects of peripheral cold exposure on myocardial perfusion and function were studied in 13 patients with scleroderma without clinically evident myocardial disease. Ten patients had at least one transient, cold-induced, myocardial perfusion defect visualized by thallium-201 scintigraphy, and 12 had reversible, cold-induced, segmental left ventricular hypokinesis by two-dimensional echocardiography. The 10 patients with transient perfusion defects all had anatomically corresponding ventricular wall motion abnormalities. No one in either of two control groups (9 normal volunteers and 7 patients with chest pain and normal coronary arteriograms) had cold-induced abnormalities. This study is the first to show the simultaneous occurrence of cold-induced abnormalities in myocardial perfusion and function in patients with scleroderma. The results suggest that cold exposure in such patients may elicit transient reflex coronary vasoconstriction resulting in reversible myocardial ischemia and dysfunction. Chronic recurrent episodes of coronary spasm may lead to focal myocardial fibrosis.

  2. Reducing CT dose in myocardial perfusion SPECT/CT.

    PubMed

    O'Shaughnessy, Emma; Dixon, Kat L

    2015-11-01

    The aim of this study was to reduce the radiation dose arising from computed tomography (CT) attenuation correction to single photon emission computed tomography myocardial perfusion imaging studies without adversely affecting its accuracy. Using the Perspex CTDI phantom with the Xi detector to measure dose, CT scans were acquired using the Siemens Symbia T over the full range of CT settings available. Using the default setting 'AECmean', the measured dose at the centre of the phantom was 1.68 mGy and the breast dose from the scout view was 0.30 mGy. The lowest dose was achieved using the dose modulation setting in which the doses were reduced to 1.21 mGy and undetectable (<0.01 mGy), respectively. To observe the effect of changing these settings, 30 patients received a stress scan with default CT settings and a rest scan utilizing single photon emission computed tomography-guided CT and the dose modulation CT settings. Results showed a mean effective dose reduction of 23.6%. The dose reduction was greatest for larger patients, with the largest dose reduction for one patient being 72%. There was no apparent difference in attenuation correction between the two sets of resultant images. These new lower-dose settings are now applied to all clinical myocardial perfusion imaging studies. PMID:26302461

  3. Patients with reduced heart rate response to adenosine infusion have low myocardial flow reserve in (13)N-ammonia PET studies.

    PubMed

    Tomiyama, Takeshi; Kumita, Shin-ichiro; Ishihara, Keiichi; Suda, Masaya; Sakurai, Minoru; Hakozaki, Kenta; Hashimoto, Hidenobu; Takahashi, Naoto; Takano, Hitoshi; Kobayashi, Yasuhiro; Kiriyama, Tomonari; Fukushima, Yoshimitsu; Shimizu, Wataru

    2015-06-01

    To assess the effect of adenosine infusion by evaluating the relationship between heart rate (HR) response to adenosine and myocardial flow reserve (MFR) of remote regions supplied by normal coronary arteries in (13)N-ammonia PET. Thirty-one consecutive subjects (20 known coronary artery disease patients, 4 chronic heart failure patients, and 7 normal volunteers) except cases having 3-vessel disease underwent rest and adenosine stress (13)N-ammonia myocardial perfusion PET. Semi-quantitative, quantitative, and gated analyses were performed. Subjects were divided into two groups with regard to HR response to adenosine. Twenty-two subjects had normal HR response (peak/rest HR > 1.20), while reduced HR response (≤ 1.20) was observed in nine subjects. There were no differences in rest myocardial blood flow (MBF) of remote regions between the groups. Subjects with reduced HR response had significantly lower stress MBF and MFR of remote regions than those with normal HR response (stress MBF: 1.559 ± 0.517 vs. 2.279 ± 0.530, p = 0.004, MFR: 1.59 ± 0.36 vs. 2.35 ± 0.53, p = 0.001). There were no significant differences between the groups by means of semi-quantitative scoring. Rest and stress ejection fraction (EF) in the reduced HR response group was lower than that in the normal HR response group. In a multiple stepwise regression analysis, HR ratio, dyslipidemia, and Brinkman index were identified as predictors of the change in MFR of remote regions. Subjects with reduced HR response to adenosine had lower stress MBF and MFR of remote regions and lower EF. Moreover, HR response was one of the predictors of the change in MFR of remote regions. PMID:25846547

  4. Comparison of myocardial contrast echocardiography with NC100100 and 99mTc sestamibi SPECT for detection of resting myocardial perfusion abnormalities in patients with previous myocardial infarction

    PubMed Central

    Jucquois, I; Nihoyannopoulos, P; D'Hondt, A; Roelants, V; Robert, A; Melin, J; Glass, D; Vanoverschelde, J

    2000-01-01

    OBJECTIVE—To determine whether myocardial contrast echocardiography (MCE) following intravenous injection of perfluorocarbon microbubbles permits identification of resting myocardial perfusion abnormalities in patients who have had a previous myocardial infarction.
PATIENTS AND INTERVENTIONS—22 patients (mean (SD) age 66 (11) years) underwent MCE after intravenous injection of NC100100, a novel perfluorocarbon containing contrast agent, and resting 99mTc sestamibi single photon emission computed tomography (SPECT). With both methods, myocardial perfusion was graded semiquantitatively as 1 = normal, 0.5 = mild defect, and 0 = severe defect.
RESULTS—Among the 203 normally contracting segments, 151 (74%) were normally perfused by SPECT and 145 (71%) by MCE. With SPECT, abnormal tracer uptake was mainly found among normally contracting segments from the inferior wall. By contrast, with MCE poor myocardial opacification was noted essentially among the normally contracting segments from the anterior and lateral walls. Of the 142 dysfunctional segments, 87 (61%) showed perfusion defects by SPECT, and 94 (66%) by MCE. With both methods, perfusion abnormalities were seen more frequently among akinetic than hypokinetic segments. MCE correctly identified 81/139 segments that exhibited a perfusion defect by SPECT (58%), and 135/206 segments that were normally perfused by SPECT (66%). Exclusion of segments with attenuation artefacts (defined as abnormal myocardial opacification or sestamibi uptake but normal contraction) by either MCE or SPECT improved both the sensitivity (76%) and the specificity (83%) of the detection of SPECT perfusion defects by MCE.
CONCLUSIONS—The data suggest that MCE allows identification of myocardial perfusion abnormalities in patients who have had a previous myocardial infarction, provided that regional wall motion is simultaneously taken into account.


Keywords: myocardial contrast echocardiography; NC100100

  5. Assessment of myocardial perfusion and viability by positron emission tomography.

    PubMed

    Anagnostopoulos, Constantinos; Georgakopoulos, Alexandros; Pianou, Nikoletta; Nekolla, Stephan G

    2013-09-01

    An important evolution has taken place recently in the field of cardiovascular Positron Emission Tomography (PET) imaging. Being originally a highly versatile research tool that has contributed significantly to advance our understanding of cardiovascular physiology and pathophysiology, PET has gradually been incorporated into the clinical cardiac imaging portfolio contributing to diagnosis and management of patients investigated for coronary artery disease (CAD). PET myocardial perfusion imaging (MPI) has an average sensitivity and specificity around 90% for the detection of angiographically significant CAD and it is also a very accurate technique for prognostication of patients with suspected or known CAD. In clinical practice, Rubidium-82 ((82)Rb) is the most widely used radiopharmaceutical for MPI that affords also accurate and reproducible quantification in absolute terms (ml/min/g) comparable to that obtained by cyclotron produced tracers such as Nitrogen-13 ammonia ((13)N-ammonia) and Oxygen-15 labeled water ((15)O-water). Quantification increases sensitivity for detection of multivessel CAD and it may also be helpful for detection of early stages of atherosclerosis or microvascular dysfunction. PET imaging combining perfusion with myocardial metabolism using (18)F-Fluorodeoxyglucose ((18)F FDG), a glucose analog, is an accurate standard for assessment of myocardial hibernation and risk stratification of patients with left ventricular dysfunction of ischemic etiology. It is helpful for guiding management decisions regarding revascularization or medical treatment and predicting improvement of symptoms, exercise capacity and quality of life post-revascularization. The strengths of PET can be increased further with the introduction of hybrid scanners, which combine PET with computed tomography (PET/CT) or with magnetic resonance imaging (PET/MRI) offering integrated morphological, biological and physiological information and hence, comprehensive evaluation of

  6. Myocardial Perfusion: Characteristics of Distal Intramyocardial Arteriolar Trees.

    PubMed

    Zamir, Mair; Vercnocke, Andrew J; Edwards, Phillip K; Anderson, Jill L; Jorgensen, Steven M; Ritman, Erik L

    2015-11-01

    A combination of experimental, theoretical, and imaging methodologies is used to examine the hierarchical structure and function of intramyocardial arteriolar trees in porcine hearts to provide a window onto a region of myocardial microvasculature which has been difficult to fully explore so far. A total of 66 microvascular trees from 6 isolated myocardial specimens were analyzed, with a cumulative number of 2438 arteriolar branches greater than or equal to 40 μm lumen diameter. The distribution of flow rates within each tree was derived from an assumed power law relationship for that tree between the diameter of vessel segments and flow rates that are consistent with that power law and subject to conservation of mass along hierarchical structure of the tree. The results indicate that the power law index increases at levels of arteriolar vasculature closer to the capillary level, consistent with a concomitant decrease in shear stress acting on endothelial tissue. These results resolve a long standing predicament which could not be resolved previously because of lack of data about the 3D, interconnected, arterioles. In the context of myocardial perfusion, the results indicate that the coefficient of variation of flow rate in pre-capillary distal arterioles is high, suggesting that heterogeneity of flow rate in these arterioles is not entirely random but may be due at least in part to active control. PMID:25952363

  7. Myocardial perfusion as an indicator of graft patency after coronary artery bypass surgery. [Thallium 201

    SciTech Connect

    Kolibash, A.J.; Call, T.D.; Bush, C.A.; Tetalman, M.R.; Lewis, R.P.

    1980-05-01

    Stress and resting myocardial perfusion were assessed in 38 patients who received 96 grafts. Stress perfusion was evaluated with thallium-201 and resting myocardial blood flow distribution with radiolabeled particles. When both stress and rest perfusion were normal, graft patency was 82% (51 of 62 grafts). Graft patency was also high (81%, 13 of 16) in areas where stress perfusion abnormalities resolved or become less apparent at rest. However, when stress perfusion defects remained unchanged at rest, the graf was likely to be occuluded (73%, 11 of 15). Maintenance of normal rest perfusion or improvement of rest perfusion postoperatively was also associated with a high graft patency rate (80%, 35 of 44), whereas the development of new rest perfusion defects postoperatively implied graft occlusion (86%, six of seven).

  8. Prognostic Utility of Calcium Scoring as an Adjunct to Stress Myocardial Perfusion Scintigraphy in End-Stage Renal Disease

    PubMed Central

    Moody, William E.; Lin, Erica L.S.; Stoodley, Matthew; McNulty, David; Thomson, Louise E.; Berman, Daniel S.; Edwards, Nicola C.; Holloway, Benjamin; Ferro, Charles J.; Townend, Jonathan N.; Steeds, Richard P.

    2016-01-01

    Coronary artery calcium score (CACS) is a strong predictor of adverse cardiovascular events in the general population. Recent data confirm the prognostic utility of single-photon emission computed tomographic (SPECT) imaging in end-stage renal disease, but whether performing CACS as part of hybrid imaging improves risk prediction in this population is unclear. Consecutive patients (n = 284) were identified after referral to a university hospital for cardiovascular risk stratification in assessment for renal transplantation. Participants underwent technetium-99m SPECT imaging after exercise or standard adenosine stress in those unable to achieve 85% maximal heart rate; multislice CACS was also performed (Siemens Symbia T16, Siemens, Erlangen, Germany). Subjects with known coronary artery disease (n = 88) and those who underwent early revascularization (n = 2) were excluded. The primary outcome was a composite of death or first myocardial infarction. An abnormal SPECT perfusion result was seen in 22% (43 of 194) of subjects, whereas 45% (87 of 194) had at least moderate CACS (>100 U). The frequency of abnormal perfusion (summed stress score ≥4) increased with increasing CACS severity (p = 0.049). There were a total of 15 events (8 deaths, and 7 myocardial infarctions) after a median duration of 18 months (maximum follow-up 3.4 years). Univariate analysis showed diabetes mellitus (Hazard ratio [HR] 3.30, 95% CI 1.14 to 9.54; p = 0.028), abnormal perfusion on SPECT (HR 5.32, 95% CI 1.84 to 15.35; p = 0.002), and moderate-to-severe CACS (HR 3.55, 95% CI 1.11 to 11.35; p = 0.032) were all associated with the primary outcome. In a multivariate model, abnormal perfusion on SPECT (HR 4.18, 95% CI 1.43 to 12.27; p = 0.009), but not moderate-to-severe CACS (HR 2.50, 95% CI 0.76 to 8.20; p = 0.130), independently predicted all-cause death or myocardial infarction. The prognostic value of CACS was not incremental to clinical and SPECT perfusion data (global chi

  9. Prognostic Utility of Calcium Scoring as an Adjunct to Stress Myocardial Perfusion Scintigraphy in End-Stage Renal Disease.

    PubMed

    Moody, William E; Lin, Erica L S; Stoodley, Matthew; McNulty, David; Thomson, Louise E; Berman, Daniel S; Edwards, Nicola C; Holloway, Benjamin; Ferro, Charles J; Townend, Jonathan N; Steeds, Richard P

    2016-05-01

    Coronary artery calcium score (CACS) is a strong predictor of adverse cardiovascular events in the general population. Recent data confirm the prognostic utility of single-photon emission computed tomographic (SPECT) imaging in end-stage renal disease, but whether performing CACS as part of hybrid imaging improves risk prediction in this population is unclear. Consecutive patients (n = 284) were identified after referral to a university hospital for cardiovascular risk stratification in assessment for renal transplantation. Participants underwent technetium-99m SPECT imaging after exercise or standard adenosine stress in those unable to achieve 85% maximal heart rate; multislice CACS was also performed (Siemens Symbia T16, Siemens, Erlangen, Germany). Subjects with known coronary artery disease (n = 88) and those who underwent early revascularization (n = 2) were excluded. The primary outcome was a composite of death or first myocardial infarction. An abnormal SPECT perfusion result was seen in 22% (43 of 194) of subjects, whereas 45% (87 of 194) had at least moderate CACS (>100 U). The frequency of abnormal perfusion (summed stress score ≥4) increased with increasing CACS severity (p = 0.049). There were a total of 15 events (8 deaths, and 7 myocardial infarctions) after a median duration of 18 months (maximum follow-up 3.4 years). Univariate analysis showed diabetes mellitus (Hazard ratio [HR] 3.30, 95% CI 1.14 to 9.54; p = 0.028), abnormal perfusion on SPECT (HR 5.32, 95% CI 1.84 to 15.35; p = 0.002), and moderate-to-severe CACS (HR 3.55, 95% CI 1.11 to 11.35; p = 0.032) were all associated with the primary outcome. In a multivariate model, abnormal perfusion on SPECT (HR 4.18, 95% CI 1.43 to 12.27; p = 0.009), but not moderate-to-severe CACS (HR 2.50, 95% CI 0.76 to 8.20; p = 0.130), independently predicted all-cause death or myocardial infarction. The prognostic value of CACS was not incremental to clinical and SPECT perfusion data (global chi-square change

  10. Myocardial Perfusion Imaging with a Solid State Camera: Simulation of a Very Low Dose Imaging Protocol

    PubMed Central

    Nakazato, Ryo; Berman, Daniel S.; Hayes, Sean W.; Fish, Mathews; Padgett, Richard; Xu, Yuan; Lemley, Mark; Baavour, Rafael; Roth, Nathaniel; Slomka, Piotr J.

    2012-01-01

    High sensitivity dedicated cardiac systems cameras provide an opportunity to lower injected doses for SPECT myocardial perfusion imaging (MPI), but the exact limits for lowering doses have not been determined. List mode data acquisition allows for reconstruction of various fractions of acquired counts, allowing a simulation of gradually lower administered dose. We aimed to determine the feasibility of very low dose MPI by exploring the minimal count level in the myocardium for accurate MPI. Methods Seventy nine patients were studied (mean body mass index 30.0 ± 6.6, range 20.2–54.0 kg/m2) who underwent 1-day standard dose 99mTc-sestamibi exercise or adenosine rest/stress MPI for clinical indications employing a Cadmium Zinc Telluride dedicated cardiac camera. Imaging time was 14-min with 803 ± 200 MBq (21.7 ± 5.4mCi) of 99mTc injected at stress. To simulate clinical scans with lower dose at that imaging time, we reframed the list-mode raw data to have count fractions of the original scan. Accordingly, 6 stress equivalent datasets were reconstructed corresponding to each fraction of the original scan. Automated QPS/QGS software was used to quantify total perfusion deficit (TPD) and ejection fraction (EF) for all 553 datasets. Minimal acceptable count was determined based on previous report with repeatability of same-day same-injection Anger camera studies. Pearson correlation coefficients and SD of differences with TPD for all scans were calculated. Results The correlations of quantitative perfusion and function analysis were excellent for both global and regional analysis on all simulated low-counts scans (all r ≥0.95, p<0.0001). Minimal acceptable count was determined to be 1.0 million counts for the left ventricular region. At this count level, SD of differences was 1.7% for TPD and 4.2% for EF. This count level would correspond to a 92.5 MBq (2.5 mCi) injected dose for the 14 min acquisition. Conclusion 1.0 million myocardial count images appear to be

  11. Relation of global and regional left ventricular function to tomographic thallium-201 myocardial perfusion in patients with prior myocardial infarction

    SciTech Connect

    Stratton, J.R.; Speck, S.M.; Caldwell, J.H.; Martin, G.V.; Cerqueira, M.; Maynard, C.; Davis, K.B.; Kennedy, J.W.; Ritchie, J.L.

    1988-07-01

    To determine the relation between regional myocardial perfusion and regional wall motion in humans, tomographic thallium-201 imaging and two-dimensional echocardiography at rest were performed on the same day in 83 patients 4 to 12 weeks after myocardial infarction. Myocardial perfusion and wall motion were assessed independently in five left ventricular regions (total 415 regions). Regional myocardial perfusion was quantitated as a percent of the region infarcted (range 0 to 100%) using a previously validated method. Wall motion was graded on a four point scale as 1 = normal (n = 266 regions), 2 = hypokinesia (n = 64), 3 = akinesia (n = 70), 4 = dyskinesia (n = 13) or not evaluable (n = 2). Regional wall motion correlated directly with the severity of the perfusion deficit (r = 0.68, p less than 0.0001). Among normally contracting regions, the mean perfusion defect score was only 2 +/- 4. Increasingly severe wall motion abnormalities were associated with larger perfusion defect scores (hypokinesia = 6 +/- 5, akinesia = 11 +/- 7 and dyskinesia = 18 +/- 5, all p less than 0.01 versus normal. Among regions with normal wall motion, only 3% had a perfusion defect score greater than or equal to 10. Conversely, among 68 regions with a large (greater than or equal to 10) perfusion defect, only 13% had normal motion whereas 87% had abnormal wall motion. The relation between perfusion and wall motion noted for the entire cohort was also present in subgroups of patients with anterior or inferior infarction. In patients with prior myocardial infarction, the severity of the tomographic thallium perfusion defect correlates directly with echocardiographically defined wall motion abnormalities, both globally and regionally.

  12. Bone metastasis on Tc99-m sestamibi myocardial perfusion scan

    PubMed Central

    Hatemi, Lachin; Jabi, Feraas

    2015-01-01

    A 75-year-old woman presented to our department for a stress myocardial perfusion imaging study with Tc99m-sestamibi. Incidental focal uptake, found in the left upper anterior chest, was initially felt to be located in the left breast. After additional single-photon CT imaging was performed the same day, extracardiac foci within the ribs, spine, and left lung (worrisome for active metastases) were shown to be present, with the initial focus located within a left rib rather than a breast. A review of previous radiographic and nuclear imaging studies confirmed metastatic disease from recurrent follicular thyroid cancer. Atypical focal extracardiac activity must be closely scrutinized for the possibility of malignancy, as Tc99m-sestamibi (in addition to being myocardium-avid) is tumor-avid.

  13. Adenosine A2A Agonist Improves Lung Function During Ex-vivo Lung Perfusion

    PubMed Central

    Emaminia, Abbas; LaPar, Damien J.; Zhao, Yunge; Steidle, John F.; Harris, David A.; Linden, Joel; Kron, Irving L.; Lau, Christine L.

    2012-01-01

    Background Ex-vivo lung perfusion (EVLP) is a novel technique to assess, and potentially repair marginal lungs that may otherwise be rejected for transplantation. Adenosine has been shown to protect against lung ischemia-reperfusion injury through its A2A receptor. We hypothesized that combining EVLP with adenosine A2A receptor agonist treatment would enhance lung functional quality and increase donor lung usage. Methods Eight bilateral pig lungs were harvested and flushed with cold Perfadex. After 14 hours storage at 4°C, EVLP was performed for 5 hours on two explanted lung groups: 1) Control group lungs (n=4), were perfused with Steen Solution and Dimethyl sulfoxide (DMSO), and 2) treated group lungs (n=4) received 10μM CGS21680, a selective A2A receptor agonist, in a Steen Solution-primed circuit. Lung histology, tissue cytokines, gas analysis and pulmonary function were compared between groups. Results Treated lungs demonstrated significantly less edema as reflected by wet-dry weight ratio (6.6 vs. 5.2, p<0.03) and confirmed by histology. In addition, treated lung demonstrated significantly lower levels of interferon gamma (45.1 vs. 88.5, p<0.05). Other measured tissue cytokines (interleukin (IL) 1 beta, IL-6, and IL-8) were lower in treatment group, but values failed to reach statistical significance. Oxygenation index was improved in the treated group (1.5 vs. 2.3, p<0.01) as well as mean airway pressure (10.3 vs. 13 p<0.009). Conclusions EVLP is a novel and efficient way to assess and optimize lung function and oxygen exchange within donor lungs, and the use of adenosine A2A agonist potentiates its potential. EVLP with the concomitant administration of A2A agonist may enhance donor lung quality and could increase the donor lung pool for transplantation. PMID:22051279

  14. Recent developments and future prospects of SPECT myocardial perfusion imaging.

    PubMed

    Zaman, Maseeh Uz; Hashmi, Ibrahim; Fatima, Nosheen

    2010-10-01

    Myocardial perfusion SPECT imaging is the most commonly performed functional imaging for assessment of coronary artery disease. High diagnostic accuracy and incremental prognostic value are the major benefits while suboptimal spatial resolution and significant radiation exposure are the main limitations. Its ability to detect hemodynamic significance of lesions seen on multidetector CT angiogram (MDCTA) has paved the path for a successful marriage between anatomical and functional imaging modalities in the form of hybrid SPECT/MDCTA system. In recent years, there have been enormous efforts by industry and academia to develop new SPECT imaging systems with better sensitivity, resolution, compact design and new reconstruction algorithms with ability to improve image quality and resolution. Furthermore, expected arrival of Tc-99m-labeled deoxyglucose in next few years would further strengthen the role of SPECT in imaging hibernating myocardium. In view of these developments, it seems that SPECT would enjoy its pivotal role in spite of major threat to be replaced by fluorine-18-labeled positron emission tomography perfusion and glucose metabolism imaging agents. PMID:20652774

  15. 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

  16. Rapid quantitative assessment of myocardial perfusion: spectral analysis of myocardial contrast echocardiographic images.

    PubMed

    Bae, Richard Y; Belohlavek, Marek; Greenleaf, James F; Seward, James B

    2002-01-01

    We described a novel rapid spectral analysis technique performed on raw digital in-phase quadrature (IQ) data that quantitatively differentiated perfused from nonperfused myocardium based on the simultaneous comparison of local fundamental and harmonic frequency band intensity levels. In open-chest pigs after ligation of the left anterior descending coronary artery (LAD) and continuous venous contrast infusion, the fundamental-to-harmonic intensity ratio (FHIR) for samples placed within the left ventricular (LV) cavity (10.8 +/- 1.7 dB) and perfused myocardium (13.7 +/- 1.6 dB) were significantly (P <.001) lower than for nonperfused myocardium (27.1 +/- 2.9 dB). In attenuated images, the FHIR for the LV cavity and perfused myocardium were also significantly (P <.05) lower than for the nonperfused myocardium (21.4 +/- 3.0 dB, 34.4 +/- 3.2 dB, and 40.2 +/- 4.4 dB, respectively). Spectral properties of contrast microbubbles, as characterized by the FHIR, allow for rapid quantitative assessment of myocardial perfusion from data contained in a single-image frame, without requiring background image subtraction and image averaging. PMID:11781556

  17. Gated myocardial perfusion SPECT: basic principles, technical aspects, and clinical applications.

    PubMed

    Paul, Asit K; Nabi, Hani A

    2004-12-01

    Electrocardiographically gated myocardial perfusion SPECT (GSPECT) is a state-of-the-art technique for the combined evaluation of myocardial perfusion and left ventricular function within a single study. It is currently one of the most commonly performed cardiology procedures in a nuclear medicine department. Automation of the image processing and quantification has made this technique highly reproducible, practical, and user friendly in the clinical setting. In patients with coronary artery disease, gating enhances the diagnostic and prognostic capability of myocardial perfusion imaging, provides incremental information over the perfusion data, and has shown potentials for myocardial viability assessment and sequential follow-up after therapy. After reading this article, the readers will understand (a) the general principles of GSPECT and quantitation, (b) the methods of the image acquisition and analysis, (c) validation of GSPECT with other cardiac imaging modalities, and (d) application of the GSPECT-derived functional parameters in the clinical practice. PMID:15576339

  18. The effect of nifedipine on myocardial perfusion and metabolism in systemic sclerosis. A positron emission tomographic study

    SciTech Connect

    Duboc, D.; Kahan, A.; Maziere, B.; Loc'h, C.; Crouzel, C.; Menkes, C.J.; Amor, B.; Strauch, G.; Guerin, F.; Syrota, A. )

    1991-02-01

    We assessed the effect of nifedipine on myocardial perfusion and metabolism in 9 patients with systemic sclerosis, using positron emission tomography with a perfusion tracer (potassium-38) and a metabolic tracer (18F-fluorodeoxyglucose (18FDG)). Nifedipine, 20 mg 3 times daily for 1 week, induced a significant increase in 38K myocardial uptake, a significant decrease in 18FDG myocardial uptake, and a significant increase in the myocardial 38K: 18FDG ratio. These results indicate that the increase in myocardial perfusion is associated with modifications in myocardial energy metabolism, which probably result from a beneficial anti-ischemic effect of nifedipine in patients with systemic sclerosis.

  19. 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

  20. Measurement of myocardial perfusion and infarction size using computer-aided diagnosis system for myocardial contrast echocardiography.

    PubMed

    Du, Guo-Qing; Xue, Jing-Yi; Guo, Yanhui; Chen, Shuang; Du, Pei; Wu, Yan; Wang, Yu-Hang; Zong, Li-Qiu; Tian, Jia-Wei

    2015-09-01

    Proper evaluation of myocardial microvascular perfusion and assessment of infarct size is critical for clinicians. We have developed a novel computer-aided diagnosis (CAD) approach for myocardial contrast echocardiography (MCE) to measure myocardial perfusion and infarct size. Rabbits underwent 15 min of coronary occlusion followed by reperfusion (group I, n = 15) or 60 min of coronary occlusion followed by reperfusion (group II, n = 15). Myocardial contrast echocardiography was performed before and 7 d after ischemia/reperfusion, and images were analyzed with the CAD system on the basis of eliminating particle swarm optimization clustering analysis. The myocardium was quickly and accurately detected using contrast-enhanced images, myocardial perfusion was quantitatively calibrated and a color-coded map calibrated by contrast intensity and automatically produced by the CAD system was used to outline the infarction region. Calibrated contrast intensity was significantly lower in infarct regions than in non-infarct regions, allowing differentiation of abnormal and normal myocardial perfusion. Receiver operating characteristic curve analysis documented that -54-pixel contrast intensity was an optimal cutoff point for the identification of infarcted myocardium with a sensitivity of 95.45% and specificity of 87.50%. Infarct sizes obtained using myocardial perfusion defect analysis of original contrast images and the contrast intensity-based color-coded map in computerized images were compared with infarct sizes measured using triphenyltetrazolium chloride staining. Use of the proposed CAD approach provided observers with more information. The infarct sizes obtained with myocardial perfusion defect analysis, the contrast intensity-based color-coded map and triphenyltetrazolium chloride staining were 23.72 ± 8.41%, 21.77 ± 7.8% and 18.21 ± 4.40% (% left ventricle) respectively (p > 0.05), indicating that computerized myocardial contrast echocardiography can

  1. Development of an Ex Vivo, Beating Heart Model for CT Myocardial Perfusion

    PubMed Central

    Pelgrim, Gert Jan; Das, Marco; Haberland, Ulrike; Slump, Cees; Handayani, Astri; van Tuijl, Sjoerd; Stijnen, Marco; Klotz, Ernst; Oudkerk, Matthijs; Wildberger, Joachim E.; Vliegenthart, Rozemarijn

    2015-01-01

    Objective. To test the feasibility of a CT-compatible, ex vivo, perfused porcine heart model for myocardial perfusion CT imaging. Methods. One porcine heart was perfused according to Langendorff. Dynamic perfusion scanning was performed with a second-generation dual source CT scanner. Circulatory parameters like blood flow, aortic pressure, and heart rate were monitored throughout the experiment. Stenosis was induced in the circumflex artery, controlled by a fractional flow reserve (FFR) pressure wire. CT-derived myocardial perfusion parameters were analysed at FFR of 1 to 0.10/0.0. Results. CT images did not show major artefacts due to interference of the model setup. The pacemaker-induced heart rhythm was generally stable at 70 beats per minute. During most of the experiment, blood flow was 0.9–1.0 L/min, and arterial pressure varied between 80 and 95 mm/Hg. Blood flow decreased and arterial pressure increased by approximately 10% after inducing a stenosis with FFR ≤ 0.50. Dynamic perfusion scanning was possible across the range of stenosis grades. Perfusion parameters of circumflex-perfused myocardial segments were affected at increasing stenosis grades. Conclusion. An adapted Langendorff porcine heart model is feasible in a CT environment. This model provides control over physiological parameters and may allow in-depth validation of quantitative CT perfusion techniques. PMID:26185756

  2. Severe coronary tortuosity or myocardial bridging in patients with chest pain, normal coronary arteries, and reversible myocardial perfusion defects.

    PubMed

    Gaibazzi, Nicola; Rigo, Fausto; Reverberi, Claudio

    2011-10-01

    We reviewed patients with normal or near-normal coronary angiograms enrolled in the SPAM contrast stress echocardiographic diagnostic study in which 400 patients with chest pain syndrome of suspected cardiac origin with a clinical indication to coronary angiography were enrolled. Patients underwent dipyridamole contrast stress echocardiography (cSE) with sequential analysis of wall motion, myocardial perfusion, and Doppler coronary flow reserve before elective coronary angiography. Ninety-six patients with normal or near-normal epicardial coronary arteries were screened for the presence of 2 prespecified findings: severely tortuous coronary arteries and myocardial bridging. Patients were divided in 2 groups based on the presence (false-positive results, n = 37) or absence (true-negative results, n = 59) of reversible myocardial perfusion defects during cSE and compared for history and clinical and angiographic characteristics. Prevalence of severely tortuous coronary arteries (35% vs 5%, p <0.001) or myocardial bridging (13% vs 2%, p <0.05) was 7 times higher in patients who demonstrated reversible perfusion defects at cSE compared to those without reversible perfusion defects. No significant differences were found between the 2 groups for the main demographic variables and risk factors. Patients in the false-positive group more frequently had a history of effort angina (p <0.001) and ST-segment depression at treadmill electrocardiography (p <0.001). In conclusion, we hypothesize that patients with a positive myocardial perfusion finding at cSE but without obstructive epicardial coronary artery disease have a decreased myocardial blood flow reserve, which may be caused by a spectrum of causes other than obstructive coronary artery disease, among which severely tortuous coronary arteries/myocardial bridging may play a significant role. PMID:21784382

  3. Parametric myocardial perfusion PET imaging using physiological clustering

    NASA Astrophysics Data System (ADS)

    Mohy-ud-Din, Hassan; Karakatsanis, Nikolaos A.; Lodge, Martin A.; Tang, Jing; Rahmim, Arman

    2014-03-01

    We propose a novel framework of robust kinetic parameter estimation applied to absolute ow quanti cation in dynamic PET imaging. Kinetic parameter estimation is formulated as a nonlinear least squares with spatial constraints problem (NLLS-SC) where the spatial constraints are computed from a physiologically driven clustering of dynamic images, and used to reduce noise contamination. An ideal clustering of dynamic images depends on the underlying physiology of functional regions, and in turn, physiological processes are quanti ed by kinetic parameter estimation. Physiologically driven clustering of dynamic images is performed using a clustering algorithm (e.g. K-means, Spectral Clustering etc) with Kinetic modeling in an iterative handshaking fashion. This gives a map of labels where each functionally homogenous cluster is represented by mean kinetics (cluster centroid). Parametric images are acquired by solving the NLLS-SC problem for each voxel which penalizes spatial variations from its mean kinetics. This substantially reduces noise in the estimation process for each voxel by utilizing kinetic information from physiologically similar voxels (cluster members). Resolution degradation is also substantially minimized as no spatial smoothing between heterogeneous functional regions is performed. The proposed framework is shown to improve the quantitative accuracy of Myocardial Perfusion (MP) PET imaging, and in turn, has the long-term potential to enhance capabilities of MP PET in the detection, staging and management of coronary artery disease.

  4. Assessment of myocardial perfusion in patients after the arterial switch operation

    SciTech Connect

    Vogel, M.; Smallhorn, J.F.; Gilday, D.; Benson, L.N.; Ash, J.; Williams, W.G.; Freedom, R.M. )

    1991-02-01

    In 21 patients who had undergone the arterial switch operation, the adequacy of myocardial perfusion was evaluated by thallium-201 computed scintigraphy 2.6 +/- 2 (0.3-7) yr after surgery. Fourteen patients had undergone the arterial switch procedure after pulmonary artery banding and seven as a primary repair. Isoproterenol stress increased the heart rate by at least 55%. Tomographic imaging was performed at peak stress and 3 hr later in the reperfusion phase. Nine patients had perfusion defects. The perfusion defects were located at the left ventricular apex in four (with extension to the inferolateral wall in one), left ventricular anterolateral wall in two, ventricular septum in one, left ventricular inferior wall in one, and right ventricular free wall in one. Some of these defects could be due to myocardial damage at the time of surgery, but these results also raise concern about long-term adequacy of myocardial perfusion following the arterial switch procedure.

  5. 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. PMID:22931118

  6. Myocardial perfusion and oxygenation are impaired during stress in severe aortic stenosis and correlate with impaired energetics and subclinical left ventricular dysfunction

    PubMed Central

    2014-01-01

    Background Left ventricular (LV) hypertrophy in aortic stenosis (AS) is characterized by reduced myocardial perfusion reserve due to coronary microvascular dysfunction. However, whether this hypoperfusion leads to tissue deoxygenation is unknown. We aimed to assess myocardial oxygenation in severe AS without obstructive coronary artery disease, and to investigate its association with myocardial energetics and function. Methods Twenty-eight patients with isolated severe AS and 15 controls underwent cardiovascular magnetic resonance (CMR) for assessment of perfusion (myocardial perfusion reserve index-MPRI) and oxygenation (blood-oxygen level dependent-BOLD signal intensity-SI change) during adenosine stress. LV circumferential strain and phosphocreatine/adenosine triphosphate (PCr/ATP) ratios were assessed using tagging CMR and 31P MR spectroscopy, respectively. Results AS patients had reduced MPRI (1.1 ± 0.3 vs. controls 1.7 ± 0.3, p < 0.001) and BOLD SI change during stress (5.1 ± 8.9% vs. controls 18.2 ± 10.1%, p = 0.001), as well as reduced PCr/ATP (1.45 ± 0.21 vs. 2.00 ± 0.25, p < 0.001) and LV strain (−16.4 ± 2.7% vs. controls −21.3 ± 1.9%, p < 0.001). Both perfusion reserve and oxygenation showed positive correlations with energetics and LV strain. Furthermore, impaired energetics correlated with reduced strain. Eight months post aortic valve replacement (AVR) (n = 14), perfusion (MPRI 1.6 ± 0.5), oxygenation (BOLD SI change 15.6 ± 7.0%), energetics (PCr/ATP 1.86 ± 0.48) and circumferential strain (−19.4 ± 2.5%) improved significantly. Conclusions Severe AS is characterized by impaired perfusion reserve and oxygenation which are related to the degree of derangement in energetics and associated LV dysfunction. These changes are reversible on relief of pressure overload and hypertrophy regression. Strategies aimed at improving oxygen demand–supply balance to preserve myocardial

  7. Resveratrol Improves Myocardial Perfusion in a Swine Model of Hypercholesterolemia and Chronic Myocardial Ischemia

    PubMed Central

    Robich, Michael P.; Osipov, Robert M.; Nezafat, Reza; Feng, Jun; Clements, Richard T.; Bianchi, Cesario; Boodhwani, Munir; Coady, Michael A.; Laham, Roger J.; Sellke, Frank W.

    2010-01-01

    Introduction Resveratrol may provide protection against coronary artery disease. We hypothesized that supplemental resveratrol will improve cardiac perfusion in the ischemic territory of swine with hypercholesterolemia and chronic myocardial ischemia. Methods and Results Yorkshire swine were fed either a normal diet (control, n=7), a hypercholesterolemic diet (HCC, n=7), or a hypercholesterolemic diet with supplemental resveratrol (100 mg/kg/day orally, HCRV, n=7). Four weeks later, an ameroid constrictor was placed on the left circumflex artery. Animals underwent cardiac magnetic resonance imaging and coronary angiography 7 weeks later, prior to sacrifice and tissue harvest. Total cholesterol was lowered about 30% in HCRV animals (p<0.001). Regional wall motion analysis demonstrated a significant decrease in inferolateral function from baseline to 7 weeks in HCC swine (p=0.04). There was no significant change in regional function in HCRV swine from baseline to 7 weeks (p=0.32). Tissue blood flow during stress was 2.8 fold greater in HCRV swine when compared to HCC swine (p=0.04). Endothelial dependent microvascular relaxation response to Substance P was diminished in HCC swine which was rescued by resveratrol treatment (p=0.004). Capillary density (PECAM-1 staining) demonstrated fewer capillaries in both HCC and HCRV swine v. control swine (p=0.02). Immunoblot analysis demonstrated significantly greater expression in HCRV v. HCC swine of the following markers of angiogenesis: VEGF (p=0.002), peNOS(ser1177)(p=0.04), NFkB (p=0.004), and pAkt(thr308)(p=0.001). Conclusion Supplemental resveratrol attenuates regional wall motion abnormalities, improves myocardial perfusion in the collateral dependent region, preserves endothelial dependent coronary vessel function, and upregulates markers of angiogenesis associated with the VEGF signaling pathway. PMID:20837905

  8. Steady-state first pass perfusion (SSFPP): A new approach to 3D first-pass myocardial perfusion imaging

    PubMed Central

    Giri, Shivraman; Xue, Hui; Maiseyeu, Andrei; Kroeker, Randall; Rajagopalan, Sanjay; White, Richard D.; Zuehlsdorff, Sven; Raman, Subha V.; Simonetti, Orlando P

    2013-01-01

    Purpose To describe and characterize a new approach to first-pass myocardial perfusion utilizing balanced steady-state free precession acquisition without the use of saturation recovery or other magnetization preparation. Theory The balanced steady-state free precession sequence is inherently sensitive to contrast agent enhancement of the myocardium. This sensitivity can be used to advantage in first-pass myocardial perfusion imaging by eliminating the need for magnetization preparation. Methods Bloch equation simulations, phantom experiments, and in vivo 2D imaging studies were run comparing the proposed technique with three other methods: saturation recovery spoiled gradient echo, saturation recovery steady-state free precession, and steady-state spoiled gradient echo without magnetization preparation. Additionally, an acquisition-reconstruction strategy for 3D perfusion imaging is proposed and initial experience with this approach is demonstrated in healthy subjects and one patient. Results Phantom experiments verified simulation results showing the sensitivity of the balanced steady-state free precession sequence to contrast agent enhancement in solid tissue is similar to that of magnetization-prepared acquisitions. Images acquired in normal volunteers showed the proposed technique provided superior signal and signal-to-noise ratio compared with all other sequences at baseline as well as post-contrast. Conclusion A new approach to first-pass myocardial perfusion is presented that obviates the need for magnetization preparation and provides high signal-to-noise ratio. PMID:23440705

  9. Regional myocardial perfusion at rest and during intracoronary papaverine in patients with coronary artery disease

    SciTech Connect

    Goldman, S.; Henry, R.; Ovitt, T.; Friedman, M.J.; Rosenfeld, A.; Daly, M.

    1983-03-01

    Regional myocardial perfusion was measured in 32 patients with the xenon-133 washout technique at rest and after 5 mg of intracoronary papaverine. Areas of decreased perfusion and/or decreased vasodilation were identified visually from computer-generated functional images. The locations of arteries and stenoses, obtained from identically positioned cineangiograms, were overlaid on the functional images. Perfusion rates for 62 myocardial regions were calculated and correlated with the percentage of stenosis. There was no association between degree of stenosis and perfusion at rest. Regional myocardial perfusion increased after papaverine in regions supplied by coronary arteries without stenoses (0% to 25%), 88.6 +/- 4.7 ml/min/100 gm. This increase was significantly greater (p less than 0.001) than the increase in regions supplied by 51% to 75% stenoses (23.7 +/- 6.3 ml/min/100 gm), or 76% to 99% stenoses (12.9 +/- 6.3 ml/min/100 gm), or 100% stenoses (2.5 +/- 3.8 ml/min/100 gm). Thus there was an inverse relationship between the increase in myocardial perfusion stimulated by papaverine and the degree of coronary artery stenosis measured angiographically. In regions supplied by two stenoses in series, vasodilation produced less of an increase than a single stenosis of a similar degree.

  10. Automated myocardial perfusion from coronary x-ray angiography

    NASA Astrophysics Data System (ADS)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2010-03-01

    The purpose of our study is the evaluation of an algorithm to determine the physiological relevance of a coronary lesion as seen in a coronary angiogram. The aim is to extract as much as possible information from a standard coronary angiogram to decide if an abnormality, percentage of stenosis, as seen in the angiogram, results in physiological impairment of the blood supply of the region nourished by the coronary artery. Coronary angiography, still the golden standard, is used to determine the cause of angina pectoris based on the demonstration of an important stenose in a coronary artery. Dimensions of a lesion such as length and percentage of narrowing can at present easily be calculated by using an automatic computer algorithm such as Quantitative Coronary Angiography (QCA) techniques resulting in just anatomical information ignoring the physiological relevance of the lesion. In our study we analyze myocardial perfusion images in standard coronary angiograms in rest and in artificial hyperemic phases, using a drug e.g. papaverine intracoronary. Setting a Region of Interest (ROI) in the angiogram without overlying major vessels makes it possible to calculate contrast differences as a function of time, so called time-density curves, in the basal and hyperemic phases. In minimizing motion artifacts, end diastolic images are selected ECG based in basal and hyperemic phase in an identical ROI in the same angiographic projection. The development of new algorithms for calculating differences in blood supply in the region as set are presented together with the results of a small clinical case study using the standard angiographic procedure.

  11. Early myocardial damage assessment in dystrophinopathies using 99Tcm-MIBI gated myocardial perfusion imaging

    PubMed Central

    Zhang, Li; Liu, Zhe; Hu, Ke-You; Tian, Qing-Bao; Wei, Ling-Ge; Zhao, Zhe; Shen, Hong-Rui; Hu, Jing

    2015-01-01

    Background Early detection of muscular dystrophy (MD)-associated cardiomyopathy is important because early medical treatment may slow cardiac remodeling and attenuate symptoms of cardiac dysfunction; however, no sensitive and standard diagnostic method for MD at an earlier stage has been well-recognized. Thus, the aim of this study was to test the early diagnostic value of technetium 99m-methoxyisobutylisonitrile (99Tcm-MIBI) gated myocardial perfusion imaging (G-MPI) for MD. Methods and results Ninety-one patients underwent 99Tcm-MIBI G-MPI examinations when they were diagnosed with Duchenne muscular dystrophy (DMD) (n=77) or Becker muscular dystrophy (BMD; n=14). 99Tcm-MIBI G-MPI examinations were repeated in 43 DMD patients who received steroid treatments for 2 years as a follow-up examination. Myocardial defects were observed in nearly every segment of the left ventricular wall in both DMD and BMD patients compared with controls, especially in the inferior walls and the apices by using 99Tcm-MIBI G-MPI. Cardiac wall movement impairment significantly correlated with age in the DMD and BMD groups (rs=0.534 [P<0.05] and rs=0.784 [P<0.05], respectively). Intermittent intravenous doses of glucocorticoids and continuation with oral steroid treatments significantly improved myocardial function in DMD patients (P<0.05), but not in BMD patients. Conclusion 99Tcm-MIBI G-MPI is a sensitive and safe approach for early evaluation of cardiomyopathy in patients with DMD or BMD, and can serve as a candidate method for the evaluation of progression, prognosis, and assessment of the effect of glucocorticoid treatment in these patients. PMID:26677332

  12. Effect of beam hardening on transmural myocardial perfusion quantification in myocardial CT imaging

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    The detection of subendocardial ischemia exhibiting an abnormal transmural perfusion gradient (TPG) may help identify ischemic conditions due to micro-vascular dysfunction. We evaluated the effect of beam hardening (BH) artifacts on TPG quantification using myocardial CT perfusion (CTP). We used a prototype spectral detector CT scanner (Philips Healthcare) to acquire dynamic myocardial CTP scans in a porcine ischemia model with partial occlusion of the left anterior descending (LAD) coronary artery guided by pressure wire-derived fractional flow reserve (FFR) measurements. Conventional 120 kVp and 70 keV projection-based mono-energetic images were reconstructed from the same projection data and used to compute myocardial blood flow (MBF) using the Johnson-Wilson model. Under moderate LAD occlusion (FFR~0.7), we used three 5 mm short axis slices and divided the myocardium into three LAD segments and three remote segments. For each slice and each segment, we characterized TPG as the mean "endo-to-epi" transmural flow ratio (TFR). BH-induced hypoenhancement on the ischemic anterior wall at 120 kVp resulted in significantly lower mean TFR value as compared to the 70 keV TFR value (0.29+/-0.01 vs. 0.55+/-0.01 p<1e-05). No significant difference was measured between 120 kVp and 70 keV mean TFR values on segments moderately affected or unaffected by BH. In the entire ischemic LAD territory, 120 kVp mean endocardial flow was significantly reduced as compared to mean epicardial flow (15.80+/-10.98 vs. 40.85+/-23.44 ml/min/100g; p<1e-04). At 70 keV, BH was effectively minimized resulting in mean endocardial MBF of 40.85+/-15.3407 ml/min/100g vs. 74.09+/-5.07 ml/min/100g (p=0.0054) in the epicardium. We also found that BH artifact in the conventional 120 kVp images resulted in falsely reduced MBF measurements even under non-ischemic conditions.

  13. Positron emission tomography detects tissue metabolic activity in myocardial segments with persistent thallium perfusion defects

    SciTech Connect

    Brunken, R.; Schwaiger, M.; Grover-McKay, M.; Phelps, M.E.; Tillisch, J.; Schelbert, H.R.

    1987-09-01

    Positron emission tomography with /sup 13/N-ammonia and /sup 18/F-2-deoxyglucose was used to assess myocardial perfusion and glucose utilization in 51 myocardial segments with a stress thallium defect in 12 patients. Myocardial infarction was defined by a concordant reduction in segmental perfusion and glucose utilization, and myocardial ischemia was identified by preservation of glucose utilization in segments with rest hypoperfusion. Of the 51 segments studied, 36 had a fixed thallium defect, 11 had a partially reversible defect and 4 had a completely reversible defect. Only 15 (42%) of the 36 segments with a fixed defect and 4 (36%) of the 11 segments with a partially reversible defect exhibited myocardial infarction on study with positron tomography. In contrast, residual myocardial glucose utilization was identified in the majority of segments with a fixed (58%) or a partially reversible (64%) thallium defect. All of the segments with a completely reversible defect appeared normal on positron tomography. Apparent improvement in the thallium defect on delayed images did not distinguish segments with ischemia from infarction. Thus, positron emission tomography reveals evidence of persistent tissue metabolism in the majority of segments with a fixed or partially resolving stress thallium defect, implying that markers of perfusion alone may underestimate the extent of viable tissue in hypoperfused myocardial segments.

  14. Motion and deformation tracking for short-axis echo-planar myocardial perfusion imaging.

    PubMed

    Yang, G Z; Burger, P; Panting, J; Gatehouse, P D; Rueckert, D; Pennell, D J; Firmin, D N

    1998-09-01

    The assessment of regional myocardial perfusion during the first-pass of a contrast agent bolus requires tracking of the signal time course for each myocardial segment so that a detailed perfusion map can be derived. To obtain such a map in practice, however, is not trivial because deformation of the shape of the myocardium and respiratory-induced motion render a major difficulty in this process. This study describes an automated approach for motion and deformation tracking of functional myocardial perfusion images. The effectiveness of the described method has been evaluated using a numerical phantom and results are compared with those from existing techniques which use deformable models. Preliminary results from applying our approach to 20 patients are discussed and compared with those from SPECT studies. PMID:9873904

  15. Myocardial performance and perfusion during exercise in patients with coronary artery disease caused by Kawasaki disease

    SciTech Connect

    Paridon, S.M.; Ross, R.D.; Kuhns, L.R.; Pinsky, W.W. )

    1990-01-01

    For a study of the natural history of coronary artery lesions after Kawasaki disease and their effect on myocardial blood flow reserve with exercise, five such patients underwent exercise testing on a bicycle. Oxygen consumption, carbon dioxide production, minute ventilation, and electrocardiograms were monitored continuously. Thallium-201 scintigraphy was performed for all patients. One patient stopped exercise before exhaustion of cardiovascular reserve but had no evidence of myocardial perfusion abnormalities. Four patients terminated exercise because of exhaustion of cardiovascular reserve; one had normal cardiovascular reserve and thallium scintiscans, but the remaining patients had diminished cardiovascular reserve. Thallium scintigrams showed myocardial ischemia in two and infarction in one. No patient had exercise-induced electrocardiographic changes. These results indicate that patients with residual coronary artery lesions after Kawasaki disease frequently have reduced cardiovascular reserve during exercise. The addition of thallium scintigraphy and metabolic measurements to exercise testing improved the detection of exercise-induced abnormalities of myocardial perfusion.

  16. Right and Left Ventricular Myocardial Perfusion Reserves Correlate with Right Ventricular Function and Pulmonary Hemodynamics in Patients with Pulmonary Arterial Hypertension1

    PubMed Central

    Skrok, Jan; Shehata, Monda L.; Singh, Sukhminder; Sibley, Christopher T.; Boyce, Danielle M.; Lechtzin, Noah; Girgis, Reda E.; Mathai, Steven C.; Goldstein, Thomas A.; Zheng, Jie; Lima, João A. C.; Bluemke, David A.; Hassoun, Paul M.

    2011-01-01

    Purpose: To evaluate the relationships of right ventricular (RV) and left ventricular (LV) myocardial perfusion reserves with ventricular function and pulmonary hemodynamics in patients with pulmonary arterial hypertension (PAH) by using adenosine stress perfusion cardiac magnetic resonance (MR) imaging. Materials and Methods: This HIPAA-compliant study was institutional review board approved. Twenty-five patients known or suspected to have PAH underwent right heart catheterization and adenosine stress MR imaging on the same day. Sixteen matched healthy control subjects underwent cardiac MR imaging only. RV and LV perfusion values at rest and at adenosine-induced stress were calculated by using the Fermi function model. The MR imaging–derived RV and LV functional data were calculated by using dedicated software. Statistical testing included Kruskal-Wallis tests for continuous data, Spearman rank correlation tests, and multiple linear regression analyses. Results: Seventeen of the 25 patients had PAH: 11 with scleroderma-associated PAH, and six with idiopathic PAH. The remaining eight patients had scleroderma without PAH. The myocardial perfusion reserve indexes (MPRIs) in the PAH group (median RV MPRI, 1.7 [25th–75th percentile range, 1.3–2.0]; median LV MPRI, 1.8 [25th–75th percentile range, 1.6–2.1]) were significantly lower than those in the scleroderma non-PAH (median RV MPRI, 2.5 [25th–75th percentile range, 1.8–3.9] [P = .03]; median LV MPRI, 4.1 [25th–75th percentile range, 2.6–4.8] [P = .0003]) and control (median RV MPRI, 2.9 [25th–75th percentile range, 2.6–3.6] [P < .01]; median LV MPRI, 3.6 [25th–75th percentile range, 2.7–4.1] [P < .01]) groups. There were significant correlations between biventricular MPRI and both mean pulmonary arterial pressure (mPAP) (RV MPRI: ρ = −0.59, Bonferroni P = .036; LV MPRI: ρ = −0.79, Bonferroni P < .002) and RV stroke work index (RV MPRI: ρ = −0.63, Bonferroni P = .01; LV MPRI: ρ =

  17. The effect of captopril on thallium 201 myocardial perfusion in systemic sclerosis

    SciTech Connect

    Kahan, A.; Devaux, J.Y.; Amor, B.; Menkes, C.J.; Weber, S.; Venot, A.; Strauch, G. )

    1990-04-01

    In systemic sclerosis, abnormalities of myocardial perfusion are common and may be caused by a disturbance of the coronary microcirculation. We evaluated the long-term effect of captopril (75 to 150 mg per day) on thallium 201 myocardial perfusion in 12 normotensive patients with systemic sclerosis. Captopril significantly decreased the mean (+/- SD) number of segments with thallium 201 myocardial perfusion defects (6.5 +/- 1.9 at baseline and 4.4 +/- 2.7 after 1 year of treatment with captopril; p less than 0.02) and increased the mean global thallium score (9.6 +/- 1.7 at baseline and 11.4 +/- 2.1 after captopril; p less than 0.05). In a control group of eight normotensive patients with systemic sclerosis who did not receive captopril, no significant modification in thallium results occurred. Side effects with captopril included hypotension (six patients), taste disturbances (one patient), and skin rash (one patient). These side effects subsided when the dosage was reduced. These findings demonstrate that captopril improves thallium 201 myocardial perfusion in patients with systemic sclerosis and may therefore have a beneficial effect on scleroderma myocardial disease.

  18. Low dose dynamic myocardial CT perfusion using advanced iterative reconstruction

    NASA Astrophysics Data System (ADS)

    Eck, Brendan L.; Fahmi, Rachid; Fuqua, Christopher; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2015-03-01

    Dynamic myocardial CT perfusion (CTP) can provide quantitative functional information for the assessment of coronary artery disease. However, x-ray dose in dynamic CTP is high, typically from 10mSv to >20mSv. We compared the dose reduction potential of advanced iterative reconstruction, Iterative Model Reconstruction (IMR, Philips Healthcare, Cleveland, Ohio) to hybrid iterative reconstruction (iDose4) and filtered back projection (FBP). Dynamic CTP scans were obtained using a porcine model with balloon-induced ischemia in the left anterior descending coronary artery to prescribed fractional flow reserve values. High dose dynamic CTP scans were acquired at 100kVp/100mAs with effective dose of 23mSv. Low dose scans at 75mAs, 50mAs, and 25mAs were simulated by adding x-ray quantum noise and detector electronic noise to the projection space data. Images were reconstructed with FBP, iDose4, and IMR at each dose level. Image quality in static CTP images was assessed by SNR and CNR. Blood flow was obtained using a dynamic CTP analysis pipeline and blood flow image quality was assessed using flow-SNR and flow-CNR. IMR showed highest static image quality according to SNR and CNR. Blood flow in FBP was increasingly over-estimated at reduced dose. Flow was more consistent for iDose4 from 100mAs to 50mAs, but was over-estimated at 25mAs. IMR was most consistent from 100mAs to 25mAs. Static images and flow maps for 100mAs FBP, 50mAs iDose4, and 25mAs IMR showed comparable, clear ischemia, CNR, and flow-CNR values. These results suggest that IMR can enable dynamic CTP at significantly reduced dose, at 5.8mSv or 25% of the comparable 23mSv FBP protocol.

  19. Review: comparison of PET rubidium-82 with conventional SPECT myocardial perfusion imaging

    PubMed Central

    Ghotbi, Adam A; Kjær, Andreas; Hasbak, Philip

    2014-01-01

    Nuclear cardiology has for many years been focused on gamma camera technology. With ever improving cameras and software applications, this modality has developed into an important assessment tool for ischaemic heart disease. However, the development of new perfusion tracers has been scarce. While cardiac positron emission tomography (PET) so far largely has been limited to centres with on-site cyclotron, recent developments with generator produced perfusion tracers such as rubidium-82, as well as an increasing number of PET scanners installed, may enable a larger patient flow that may supersede that of gamma camera myocardial perfusion imaging. PMID:24028171

  20. 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.

  1. 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.

  2. Beam hardening artifact reduction using dual energy computed tomography: implications for myocardial perfusion studies

    PubMed Central

    Carrascosa, Patricia; Cipriano, Silvina; De Zan, Macarena; Deviggiano, Alejandro; Capunay, Carlos; Cury, Ricardo C.

    2015-01-01

    Background Myocardial computed tomography perfusion (CTP) using conventional single energy (SE) imaging is influenced by the presence of beam hardening artifacts (BHA), occasionally resembling perfusion defects and commonly observed at the left ventricular posterobasal wall (PB). We therefore sought to explore the ability of dual energy (DE) CTP to attenuate the presence of BHA. Methods Consecutive patients without history of coronary artery disease who were referred for computed tomography coronary angiography (CTCA) due to atypical chest pain and a normal stress-rest SPECT and had absence or mild coronary atherosclerosis constituted the study population. The study group was acquired using DE and the control group using SE imaging. Results Demographical characteristics were similar between groups, as well as the heart rate and the effective radiation dose. Myocardial signal density (SD) levels were evaluated in 280 basal segments among the DE group (140 PB segments for each energy level from 40 to 100 keV; and 140 reference segments), and in 40 basal segments (at the same locations) among the SE group. Among the DE group, myocardial SD levels and myocardial SD ratio evaluated at the reference segment were higher at low energy levels, with significantly lower SD levels at increasing energy levels. Myocardial signal-to-noise ratio was not significantly influenced by the energy level applied, although 70 keV was identified as the energy level with the best overall signal-to-noise ratio. Significant differences were identified between the PB segment and the reference segment among the lower energy levels, whereas at ≥70 keV myocardial SD levels were similar. Compared to DE reconstructions at the best energy level (70 keV), SE acquisitions showed no significant differences overall regarding myocardial SD levels among the reference segments. Conclusions BHA that influence the assessment of myocardial perfusion can be attenuated using DE at 70 keV or higher. PMID

  3. Does Enhanced External Counterpulsation (EECP) Significantly Affect Myocardial Perfusion?: A Systematic Review & Meta-Analysis

    PubMed Central

    Qin, Xiaoxia; Deng, Yanye; Wu, Dandong; Yu, Lehua; Huang, Rongzhong

    2016-01-01

    Background Enhanced external counterpulsation (EECP) is currently applied for treating coronary artery disease (CAD) patients. However, the mechanism(s) by which EECP ameliorates angina pectoris and long-term left ventricular function remain largely unknown. The aim of this study will be to assess whether EECP significantly affects myocardial perfusion in CAD patients through a systematic review and meta-analysis of the available literature. Methods MEDLINE, EMBASE, and Cochrane CENTRAL databases were searched for prospective studies on CAD patients that underwent EECP and reported myocardial perfusion data pre- and post-EECP. The impact of EECP was assessed based on the weighted mean difference (WMD) in myocardial perfusion from pre-EECP to post-EECP. Statistical heterogeneity was assessed by the I2 index. Publication bias was assessed through visual inspection of the funnel plot as well as Begg’s and Egger’s testing. Results Standard EECP therapy (i.e., 35–36 one-hour sessions within a seven-week period) significantly increased myocardial perfusion in CAD patients (pooled WMD: -0.19, 95% CI: -0.38 to 0.00, p = 0.049). A random effects analysis was applied on account of significant heterogeneity (I2 = 89.1%, p = 0.000). There was no evidence of significant publication bias (Begg’s p = 0.091; Egger’s p = 0.282). Conclusions Standard EECP therapy significantly increases myocardial perfusion in CAD patients. This study’s findings support the continued use of standard EECP therapy in CAD patients and provides one putative physiological mechanism to help explain the improvements in angina pectoris and long-term left ventricular function observed in CAD patients after EECP therapy. PMID:27045935

  4. Non-rigid registration and KLT filter to improve SNR and CNR in GRE-EPI myocardial perfusion imaging.

    PubMed

    Mihai, Georgeta; Ding, Yu; Xue, Hui; Chung, Yiu-Cho; Rajagopalan, Sanjay; Guehring, Jens; Simonetti, Orlando P

    2012-12-01

    The purpose of the study was to evaluate the effect of motion compensation by non-rigid registration combined with the Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and contrast-to-noise ratio (CNR) of hybrid gradient-echo echoplanar (GRE-EPI) first-pass myocardial perfusion imaging. Twenty one consecutive first-pass adenosine stress perfusion MR data sets interpreted positive for ischemia or infarction were processed by non-rigid Registration followed by KLT filtering. SNR and CNR were measured in abnormal and normal myocardium in unfiltered and KLT filtered images following non-rigid registration to compensate for respiratory and other motions. Image artifacts introduced by filtering in registered and nonregistered images were evaluated by two observers. There was a statistically significant increase in both SNR and CNR between normal and abnormal myocardium with KLT filtering (mean SNR increased by 62.18% ± 21.05% and mean CNR increased by 58.84% ± 18.06%; p = 0.01). Motion correction prior to KLT filtering reduced significantly the occurrence of filter induced artifacts (KLT only-artifacts in 42 out of 55 image series vs. registered plus KLT-artifacts in 3 out of 55 image series). In conclusion the combination of non- rigid registration and KLT filtering was shown to increase the SNR and CNR of GRE-EPI perfusion images. Subjective evaluation of image artifacts revealed that prior motion compensation significantly reduced the artifacts introduced by the KLT filtering process. PMID:23936584

  5. Inosculation and perfusion of pre-vascularized tissue patches containing aligned human microvessels after myocardial infarction.

    PubMed

    Riemenschneider, Sonja B; Mattia, Donald J; Wendel, Jacqueline S; Schaefer, Jeremy A; Ye, Lei; Guzman, Pilar A; Tranquillo, Robert T

    2016-08-01

    A major goal of tissue engineering is the creation of pre-vascularized tissues that have a high density of organized microvessels that can be rapidly perfused following implantation. This is especially critical for highly metabolic tissues like myocardium, where a thick myocardial engineered tissue would require rapid perfusion within the first several days to survive transplantation. In the present work, tissue patches containing human microvessels that were either randomly oriented or aligned were placed acutely on rat hearts post-infarction and for each case it was determined whether rapid inosculation could occur and perfusion of the patch could be maintained for 6 days in an infarct environment. Patches containing self-assembled microvessels were formed by co-entrapment of human blood outgrowth endothelial cells and human pericytes in fibrin gel. Cell-induced gel contraction was mechanically-constrained resulting in samples with high densities of microvessels that were either randomly oriented (with 420 ± 140 lumens/mm(2)) or uniaxially aligned (with 940 ± 240 lumens/mm(2)) at the time of implantation. These patches were sutured onto the epicardial surface of the hearts of athymic rats following permanent ligation of the left anterior descending artery. In both aligned and randomly oriented microvessel patches, inosculation occurred and perfusion of the transplanted human microvessels was maintained, proving the in vivo vascularization potential of these engineered tissues. No difference was found in the number of human microvessels that were perfused in the randomly oriented (111 ± 75 perfused lumens/mm(2)) and aligned (173 ± 97 perfused lumens/mm(2)) patches. Our results demonstrate that tissue patches containing a high density of either aligned or randomly oriented human pre-formed microvessels achieve rapid perfusion in the myocardial infarct environment - a necessary first-step toward the creation of a thick, perfusable heart patch. PMID

  6. Simultaneous Noninvasive Determination of Regional Myocardial Perfusion and Oxygen Content in Rabbits: Toward Direct Measurement of Myocardial Oxygen Consumption at MR Imaging1

    PubMed Central

    Reeder, Scott B.; Holmes, A. Alexander; McVeigh, Elliot R.; Forder, John R.

    2007-01-01

    PURPOSE To determine whether myocardial arterial perfusion and oxygen concentration can be quantified simultaneously from the same images by using spin labeling and the blood oxygenation level-dependent (BOLD) effect with fast spin-echo (SE) imaging. MATERIALS AND METHODS A T2-weighted fast SE pulse sequence was written to image isolated, arrested, blood-perfused rabbit hearts (n = 6) at 4.7 T. Perfusion images with intensity in units of milliliters per minute per gram that covered the entire left ventricle with 0.39 × 0.39 × 3.00-mm resolution were obtained in less than 15 minutes with a 32-fold reduction in imaging time from that of a previous study. Estimates of oxygen concentration were made from the same images acquired for calculation of perfusion images. RESULTS Estimates of regional myocardial oxygen content could be made from the perfusion images; this demonstrated the feasibility of three-dimensional calculation of regional oxygen consumption, which requires concomitant measurement of both oxygen content and flow. Fast SE imaging was shown to bas sensitive to hemoglobin desaturation as standard SE imaging. Perfusion abnormalities and oxygen deficits were easily identified and verified qualitatively with gadopentetate dimeglumine on both perfusion and BOLD images obtained after coronary arterial ligation. CONCLUSION T2-weighted fast SE imaging combined with perfusion-sensitive spin labeling can be used to measure myocardial arterial perfusion and oxygen concentration. This provides the groundwork for calculation of regional myocardial oxygen consumption. PMID:10478241

  7. Quantitative myocardial perfusion imaging by cardiovascular magnetic resonance and positron emission tomography.

    PubMed

    Bratis, K; Mahmoud, I; Chiribiri, A; Nagel, E

    2013-10-01

    Recent studies have demonstrated that a detailed knowledge of the extent of angiographic coronary artery disease (CAD) is not a prerequisite for clinical decision making, and the clinical management of patients with CAD is more and more focused towards the identification of myocardial ischemia and the quantification of ischemic burden. In this view, non-invasive assessment of ischemia and in particular stress imaging techniques are emerging as preferred and non-invasive options. A quantitative assessment of regional myocardial perfusion can provide an objective estimate of the severity of myocardial injury and may help clinicians to discriminate regions of the heart that are at increased risk for myocardial infarction. Positron emission tomography (PET) has established itself as the reference standard for myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) quantification. Cardiac magnetic resonance (CMR) is increasingly used to measure MBF and MPR by means of first-pass signals, with a well-defined diagnostic performance and prognostic value. The aim of this article is to review the currently available evidence on the use of both PET and CMR for quantification of MPR, with particular attention to the studies that directly compared these two diagnostic methods. PMID:23868071

  8. Selective cerebro-myocardial perfusion in complex congenital aortic arch pathology: a novel technique.

    PubMed

    De Rita, Fabrizio; Lucchese, Gianluca; Barozzi, Luca; Menon, Tiziano; Faggian, Giuseppe; Mazzucco, Alessandro; Luciani, Giovanni Battista

    2011-11-01

    Simultaneous cerebro-myocardial perfusion has been described in neonatal and infant arch surgery, suggesting a reduction in cardiac morbidity. Here reported is a novel technique for selective cerebral perfusion combined with controlled and independent myocardial perfusion during surgery for complex or recurrent aortic arch lesions. From April 2008 to April 2011, 10 patients with arch pathology underwent surgery (two hypoplastic left heart syndrome [HLHS], four recurrent arch obstruction, two aortic arch hypoplasia + ventricular septal defect [VSD], one single ventricle + transposition of the great arteries + arch hypoplasia, one interrupted aortic arch type B + VSD). Median age was 63 days (6 days-36 years) and median weight 4.0 kg (1.6-52). Via midline sternotomy, an arterial cannula (6 or 8 Fr for infants) was directly inserted into the innominate artery or through a polytetrafluoroethylene (PTFE) graft (for neonates <2.0 kg). A cardioplegia delivery system was inserted into the aortic root. Under moderate hypothermia, ascending and descending aorta were cross-clamped, and "beating heart and brain" aortic arch repair was performed. Arch repair was composed of patch augmentation in five, end-to-side anastomosis in three, and replacement in two patients. Average cardiopulmonary bypass time was 163 ± 68 min (71-310). In two patients only (one HLHS, one complex single ventricle), a period of cardiac arrest was required to complete intracardiac repair. In such cases, antegrade blood cardioplegia was delivered directly via the same catheter used for selective myocardial perfusion. Average time of splanchnic ischemia during cerebro-myocardial perfusion was 39 ± 18 min (17-69). Weaning from cardiopulmonary bypass was achieved without inotropic support in three and with low dose in seven patients. One patient required veno-arterial extracorporeal membrane oxygenation. Four patients, body weight <3.0 kg, needed delayed sternal closure. No neurologic dysfunction was noted

  9. Measurement of both left ventricular function and regional myocardial perfusion with 133Xe in dogs.

    PubMed

    Ruddy, T D; Yasuda, T; Barlai-Kovach, M; Nedelman, M A; Moore, R H; Alpert, N M; Correia, J A; Newell, J B; Okada, R D; Boucher, C A

    1987-01-01

    A technique to measure left ventricular (LV) function and myocardial perfusion was validated in 12 dogs. 133Xe in saline was injected into the left atrium (LA) or LV and two data sets were obtained using gamma camera imaging: 1) A first pass gated scan for LV function; followed by 2) Sequential images for regional myocardial perfusion. LV ejection fraction and wall motion measurements from the 133Xe blood pool images were compared to ejection fraction (r = 0.88, P less than 0.01) and wall motion (r = 0.83, P less than 0.01) data from 99mTc labeled blood pool scans. The perfusion measurements obtained with the 133Xe method were compared to microsphere data (r = 0.79, P less than 0.01). Measurements after LV 133Xe injection were similar to data following LA injection. Thus, quantitative assessment of global LV function, regional wall motion and myocardial perfusion is possible with LA or LV 133Xe injection and gamma camera imaging. PMID:3569342

  10. 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.

  11. The imaging of myocardial perfusion with 81mKr during coronary arteriography.

    PubMed

    Kleynhans, P H; Lötter, M G; van Aswegen, A; Herbst, C P; Marx, J D; Minnaar, P C

    1982-01-01

    The use of 81mKr was investigated for imaging myocardial perfusion during coronary arteriography using conventional catheters. When the significance of stenosis judged by arteriography is unclear, the effect on tissue perfusion can be established and the contribution to collateral flow by each artery separately evaluated. The distribution of 81mKr, due to its 13-s half-life, represents regional blood flow. In order to evaluate interventions, studies can be repeated at a low radiation risk to patients. A sterile pyrogen-free 81Rb-81Kr generator was developed. With slow infusion, inadequate mixing and streaming takes place due to laminar flow in coronary arteries. Fast intermittent 3-ml 81Kr-dextrose bolus injections convincingly eliminated streaming artefacts. Imaging was performed in 13 patients with a mobile scintillation camera and digital imaging system. Blood flow was calculated using the inert gas washout technique. There was good correlation (r = 0.91) between coronary blood flow determinations using 81mKr and 133Xe respectively. The perfusion images correlated well with the coronary angiograms. Total coronary arterial occlusions as demonstrated by arteriography were all shown as perfusion defects during rest. During atrial pacing myocardial flow was increased two-fold in normal coronary arteries and to a lesser extent in arteries with significant disease. The most critical lesion in a branch of a left coronary artery leads to a redistribution of perfusion during pacing. PMID:7128629

  12. Myocardial perfusion analysis in cardiac computed tomography angiographic images at rest.

    PubMed

    Xiong, Guanglei; Kola, Deeksha; Heo, Ran; Elmore, Kimberly; Cho, Iksung; Min, James K

    2015-08-01

    Cardiac computed tomography angiography (CTA) is a non-invasive method for anatomic evaluation of coronary artery stenoses. However, CTA is prone to artifacts that reduce the diagnostic accuracy to identify stenoses. Further, CTA does not allow for determination of the physiologic significance of the visualized stenoses. In this paper, we propose a new system to determine the physiologic manifestation of coronary stenoses by assessment of myocardial perfusion from typically acquired CTA images at rest. As a first step, we develop an automated segmentation method to delineate the left ventricle. Both endocardium and epicardium are compactly modeled with subdivision surfaces and coupled by explicit thickness representation. After initialization with five anatomical landmarks, the model is adapted to a target image by deformation increments including control vertex displacements and thickness variations guided by trained AdaBoost classifiers, and regularized by a prior of deformation increments from principal component analysis (PCA). The evaluation using a 5-fold cross-validation demonstrates the overall segmentation error to be 1.00 ± 0.39 mm for endocardium and 1.06 ± 0.43 mm for epicardium, with a boundary contour alignment error of 2.79 ± 0.52. Based on our LV model, two types of myocardial perfusion analyzes have been performed. One is a perfusion network analysis, which explores the correlation (as network edges) pattern of perfusion between all pairs of myocardial segments (as network nodes) defined in AHA 17-segment model. We find perfusion network display different patterns in the normal and disease groups, as divided by whether significant coronary stenosis is present in quantitative coronary angiography (QCA). The other analysis is a clinical validation assessment of the ability of the developed algorithm to predict whether a patient has significant coronary stenosis when referenced to an invasive QCA ground truth standard. By training three machine

  13. Improvement of inter-services communication through a CDSS dedicated to myocardial perfusion scintigraphy.

    PubMed

    Nies, Julie; Georg, Gersende; Faraggi, Marc; Colombet, Isabelle; Durieux, Pierre

    2011-01-01

    This study addresses the question of communication between medical wards and the nuclear medicine department for the realization of myocardial perfusion scintigraphy. It analyses the effects of a reminder for completing the content of an order form. It shows that the CDSS impacted ordering practices. It could be seen as a system enabling to structure the information and improve the quality of orders. PMID:21893729

  14. PERFUSION FOR MYOCARDIAL REVASCULARIZATION WITHOUT AN ARTIFICIAL OXYGENATOR (New Method to Reduce Surgical Morbidity)

    PubMed Central

    De Moraes, Domingos Junqueira; Abilio, Fued Michel; Cunha, Marcos; Feitosa, Lionicio A.; Aragão, Esmeraldino; Cysne, Eumenes; Vieira, Roberto; Glavam, Haroldo C. C.; Zaniolo, Waldomiro; Netto, Mario Salles; Villela, Ronaldo De A.; Labrunie, Pierre

    1979-01-01

    Thirteen patients were submitted to direct myocardial revascularization (saphenous vein graft) without the use of an artificial oxygenator. The perfusion was done by a left ventricle-to-aorta bypass and autogenous oxygenation. Most patients had three grafts implanted plus endarterectomy of the distal right coronary artery. There was one hospital death that was apparently not related to the method used. Perfusion time ranged from 45 minutes to 4 hours. Body temperature during perfusion was kept between 25 and 30° C. Perfusion flow was maintained between 25 to 50 ml per kg of body weight per minute. Ischemic, hypothermic cardiac arrest was employed. We demonstrated for the first time that perfusion for this kind of heart surgery could be done with no artificial oxygenators and, apparently, is safer for the patients. There were no bleeding problems even in perfusions as long as 4 hours. There was no respiratory dysfunction, and artificial respiration was used for only 6 to 12 hours. The patients awoke at the end of surgery with no signs or symptoms of central nervous system damage, and vasopressor drugs were rarely used after surgery. Although the experience is very small, it suggests that many postoperative problems, especially those related to bleeding and respiratory dysfunction may be reduced or eliminated by this new method. PMID:15216319

  15. Segmental analysis of thallium 201 myocardial perfusion scintigraphy: its value in a community hospital.

    PubMed

    Tendera, M; Campbell, W B; Moyers, J R

    1984-08-01

    In a community hospital, we correlated results of thallium 201 myocardial scintigraphy with coronary arteriographic data in 79 patients. Scintigraphy was 92% sensitive and 85% specific in detecting coronary artery disease. There were no false-negative scintigrams in patients with double or triple vessel disease. The most important factors determining sensitivity of the method in detecting individual coronary stenoses were (1) location of the stenosis in the coronary tree, (2) number of vessels involved, and (3) degree of obstruction. Higher prevalence of perfusion defects in areas of 90% to 99% stenosis as compared with 50% to 89% lesions was of borderline statistical significance (86% vs 59%; P = .06). Myocardial perfusion scintigraphy was unable to predict the number of significantly narrowed coronary vessels. Predictive value of a perfusion defect for a significant coronary stenosis was 87% for anterior, 88% for septal, 90% for lateral, 89% for posterior, and 78% for inferior segment. We conclude that segmental analysis of myocardial scintigrams may be of value in a community hospital. PMID:6463700

  16. Changes in myocardial perfusion reserve after PTCA: noninvasive assessment with positron tomography

    SciTech Connect

    Goldstein, R.A.; Kirkeeide, R.L.; Smalling, R.W.; Nishikawa, A.; Merhige, M.E.; Demer, L.L.; Mullani, N.A.; Gould, K.L.

    1987-08-01

    The effect of percutaneous transluminal coronary angioplasty (PTCA) on myocardial perfusion reserve has not been previously determined. Accordingly, 11 patients underwent positron imaging with (/sup 13/N)ammonia or /sup 82/Rb at rest and following dipyridamole + handgrip stress before and after PTCA. The ratio of stress to rest activity (S:R) was determined for each region of interest. Relative myocardial perfusion reserve by positron tomography (RMPR) was calculated by dividing S:R of the stenotic area by a corresponding value from a normal reference area of the same patient. Automated quantitative coronary arteriography was used to objectively measure the percent diameter (%D) and the percent area narrowing (%A) of the stenoses. In nine patients with successful PTCA, %D and %A improved (68 +/- 10 to 49 +/- 15% and 92 +/- 3 to 72 +/- 5%) and RMPR increased from 0.79 +/- 0.07 to 0.96 +/- 0.05. In the two patients in whom PTCA was unsuccessful, RMPR was unchanged. Changes in RMPR correlated inversely with changes in %D (r = -0.68) and %A (r = -0.92) and directly with improved coronary flow reserve derived from all stenosis measurements (r = 0.73, p less than 0.001 for each). This study suggests that dipyridamole + handgrip stress imaging with PET can be used to assess changes in myocardial perfusion reserve before and after PTCA with the potential for determining restenosis noninvasively.

  17. Evidence for myocardial CT perfusion imaging in the diagnosis of hemodynamically significant coronary artery disease

    PubMed Central

    2015-01-01

    This editorial discusses a recent paper published in the August issue of Radiology about the diagnostic value of myocardial computer tomography (CT) perfusion imaging in the detection of hemodynamically significant coronary stenosis when compared to single-photon emission CT (SPECT) imaging based on a secondary analysis of CORE320 study. Three aspects including high diagnostic sensitivity of CT perfusion imaging, moderate specificity of SPECT imaging and lack of use of attenuation correction in SPECT imaging have been discussed with reference to the current literature, and some suggestions have been highlighted for future studies to improve the diagnostic performance of CT perfusion and SPECT imaging in the diagnostic evaluation of coronary artery disease. PMID:25774349

  18. Myocardial uptake of cocaine and effects of cocaine on myocardial substrate utilization and perfusion in hypertensive rats

    SciTech Connect

    Som, P.; Wang, G.J.; Oster, Z.H.; Knapp, F.F. Jr.; Yonekura, Y.; Fujibayashi, Y.; Yamamoto, K.; Kubota, K.

    1992-12-31

    Cocaine abuse is a problem causing world-wide concern and the number of deaths following cocaine use is increasing. Cardiovascular complications following cocaine include severe tachyarrythmias, pulmonary edema, myocardial infarction, and acute renal failure, which are major problems confronting emergency facilities. While the studies of cocaine effects on the brain have been given the most attention, it is clear that the effects of cocaine on the cardiovascular system are of great importance, given the increasing number of reports on sudden death and myocardial infarctions in young adults related to cocaine use. The precise mechanisms of cardiotoxic actions of cocaine are unclear. We investigated the whole-body distribution of C-14-labeled cocaine to determine the cocaine-binding sites, including blocking experiments to determine the nature of regional binding sites, and differential response of the normal vs. diseased heart (hypertensive cardiomyopathy) in an animal model to mimic a potentially high risk population. We investigated the acute effects of cocaine on myocardial metabolism using two myocardial energy substrate analogs, fatty acid and glucose with comparison with regional perfusion.

  19. Myocardial uptake of cocaine and effects of cocaine on myocardial substrate utilization and perfusion in hypertensive rats

    SciTech Connect

    Som, P.; Wang, G.J. ); Oster, Z.H. ); Knapp, F.F. Jr. ); Yonekura, Y. . Faculty of Medicine); Fujibayashi, Y. . Hospital); Yamamoto, K. . Medical School); Kubota, K. (Tohoku Univ., Sendai

    1992-01-01

    Cocaine abuse is a problem causing world-wide concern and the number of deaths following cocaine use is increasing. Cardiovascular complications following cocaine include severe tachyarrythmias, pulmonary edema, myocardial infarction, and acute renal failure, which are major problems confronting emergency facilities. While the studies of cocaine effects on the brain have been given the most attention, it is clear that the effects of cocaine on the cardiovascular system are of great importance, given the increasing number of reports on sudden death and myocardial infarctions in young adults related to cocaine use. The precise mechanisms of cardiotoxic actions of cocaine are unclear. We investigated the whole-body distribution of C-14-labeled cocaine to determine the cocaine-binding sites, including blocking experiments to determine the nature of regional binding sites, and differential response of the normal vs. diseased heart (hypertensive cardiomyopathy) in an animal model to mimic a potentially high risk population. We investigated the acute effects of cocaine on myocardial metabolism using two myocardial energy substrate analogs, fatty acid and glucose with comparison with regional perfusion.

  20. Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy

    PubMed Central

    Eftekhari, Mohammad; Anbiaei, Robabeh; Zamani, Hanie; Fallahi, Babak; Beiki, Davood; Ameri, Ahmad; Emami-Ardekani, Alireza; Fard-Esfahani, Armaghan; Gholamrezanezhad, Ali; Seid Ratki, Kazem Razavi; Roknabadi, Alireza Momen

    2015-01-01

    Objective(s): Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right–sided cancer. Methods: To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring) were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT) to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions) over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol) was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. Results: A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed) and 36 patients with right-sided cancer (controls)] were enrolled. Dose-volume histogram (DVH) [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46). In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03) and anterolateral (17.1% versus 2.8%, P=0.049) walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS) of>3 was observed in twelve cases (34.3%), while in five of the controls (13.9%),(Odds ratio=1.3). There was no significant difference between the groups regarding left ventricular ejection fraction. Conclusion: The risk of radiation induced myocardial perfusion

  1. Role of myocardial perfusion imaging in evaluating thrombolytic therapy for acute myocardial infarction

    SciTech Connect

    Beller, G.A.

    1987-03-01

    Myocardial thallium-201 scintigraphy is being increasingly employed as a method for assessing the efficacy of coronary reperfusion in acute myocardial infarction. New thallium uptake after intracoronary tracer administration after successful recanalization indicates that nutrient blood flow has been successfully restored. One may also presume that some myocardial salvage occurred if thallium administered in this manner is transported intracellularly by myocytes with intact sarcolemmal membranes. However, if one injects thallium by way of the intracoronary route immediately after reperfusion, the initial uptake of thallium in reperfused myocardium may predominantly represent hyperemic flow and regional thallium counts measured may not be proportional to the mass of viable myocytes. When thallium is injected intravenously during the occlusion phase the degree of redistribution after thrombolysis is proportional to the degree of flow restoration and myocardial viability. When thallium is injected for the first time intravenously immediately after reperfusion, an overestimation of myocardial salvage may occur because of excess thallium uptake in the infarct zone consequent to significant hyperemia. Another approach to myocardial thallium scintigraphy in patients undergoing thrombolytic therapy is to administer two separate intravenous injections before and 24 hours or later after treatment. Finally, patients with acute myocardial infarction who receive intravenous thrombolytic therapy are candidates for predischarge exercise thallium-201 scintigraphy for risk stratification and detection of residual ischemia.

  2. Quantification of myocardial perfusion based on signal intensity of flow sensitized MRI

    NASA Astrophysics Data System (ADS)

    Abeykoon, Sumeda B.

    The quantitative assessment of perfusion is important for early recognition of a variety of heart diseases, determination of disease severity and their cure. In conventional approach of measuring cardiac perfusion by arterial spin labeling, the relative difference in the apparent T1 relaxation times in response to selective and non-selective inversion of blood entering the region of interest is related to perfusion via a two-compartment tissue model. But accurate determination of T1 in small animal hearts is difficult and prone to errors due to long scan times. The purpose of this study is to develop a fast, robust and simple method to quantitatively assess myocardial perfusion using arterial spin labeling. The proposed method is based on signal intensities (SI) of inversion recovery slice-select, non-select and steady-state images. Especially in this method data are acquired at a single inversion time and at short repetition times. This study began by investigating the accuracy of assessment of perfusion using a two compartment system. First, determination of perfusion by T1 and SI were implemented to a simple, two-compartment phantom model. Mathematical model developed for full spin exchange models (in-vivo experiments) by solving a modified Bloch equation was modified to develop mathematical models (T1 and SI) for a phantom (zero spin exchange). The phantom result at different flow rates shows remarkable evidence of accuracy of the two-compartment model and SI, T1 methods: the SI method has less propagation error and less scan time. Next, twelve healthy C57BL/6 mice were scanned for quantitative perfusion assessment and three of them were repeatedly scanned at three different time points for a reproducibility test. The myocardial perfusion of healthy mice obtained by the SI-method, 5.7+/-1.6 ml/g/min, was similar (p=0.38) to that obtained by the conventional T1 method, 5.6+/- 2.3 ml/g/min. The reproducibility of the SI method shows acceptable results: the

  3. Changes in rest and exercise myocardial perfusion and left ventricular function 3 to 26 weeks after clinically uncomplicated acute myocardial infarction: effects of exercise training

    SciTech Connect

    Hung, J.; Gordon, E.P.; Houston, N.; Haskell, W.L.; Goris, M.L.; DeBusk, R.F.

    1984-11-01

    The effects of exercise training on exercise myocardial perfusion and left ventricular (LV) function in the first 6 months after clinically uncomplicated acute myocardial infarction (AMI) were assessed in 53 consecutive men aged 55 +/- 9 years. Symptom-limited treadmill exercise with thallium myocardial perfusion scintigraphy and symptom-limited upright bicycle ergometry with equilibrium gated radionuclide ventriculography were performed 3, 11 and 26 weeks after AMI by 23 men randomized to training and 30 randomized to no training. Peak cycle capacity increased in both groups between 3 and 26 weeks (p less than 0.01), but reached higher levels in trained than in untrained patients (803 +/- 149 vs 648 +/- 182 kg-m/min, p less than 0.01). Reversible thallium perfusion defects were significantly more frequent at 3 than at 26 weeks: 59% and 36% of patients, respectively (p less than 0.05), without significant inter-group differences. Values of LV ejection fraction at rest, submaximal and peak exercise did not change significantly in either group. The increase in functional capacity, i.e., peak treadmill or bicycle workload, that occurred 3 to 26 weeks after infarction was significantly correlated with the increase in peak exercise heart rate (p less than 0.001), but not with changes in myocardial perfusion or LV function determined by radionuclide techniques. Changes in myocardial perfusion or LV function do not appear to account for the improvement in peak functional capacity that occurs within the first 6 months after clinically uncomplicated AMI.

  4. Clinical characteristics of silent myocardial ischemia diagnosed with adenosine stress 99mTc-tetrofosmin myocardial scintigraphy in Japanese patients with acute cerebral infarction.

    PubMed

    Nomura, Tetsuya; Kusaba, Tetsuro; Kodama, Naotoshi; Terada, Kensuke; Urakabe, Yota; Nishikawa, Susumu; Keira, Natsuya; Matsubara, Hiroaki; Tatsumi, Tetsuya

    2013-01-01

    It is well known that silent myocardial ischemia (SMI) often complicates patients with cerebral infarction and that stroke patients often die of ischemic heart disease. Therefore, it is considered important to treat myocardial ischemia in stroke patients. This study investigated SMI complicating Japanese patients with fresh stroke, using (99m)Tc-tetrofosmin myocardial scintigraphy with pharmacologic stress testing to elucidate their clinical manifestations. This study included 41 patients (26 men, mean age 76.0 ± 10.7 years) with acute cerebral infarction and no history of coronary artery disease. All patients underwent (99m)Tc-tetrofosmin myocardial scintigraphy with intravenous administration of adenosine to diagnose SMI. Of the 41 patients, myocardial ischemia was confirmed in 17 patients (41.5%). Atherosclerotic etiology was the major cause of stroke in the ischemia(+) group and embolic origin was the major cause in the ischemia(-) group. Patients with myocardial ischemia had a higher incidence of diabetes mellitus (52.9 vs 20.8%; P = 0.0323) and more than two conventional cardiovascular risk factors (64.7 vs 25.0%; P = 0.0110) compared with the nonischemic patients. Infarction subtype of atherosclerotic origin was an independent positive predictor of asymptomatic myocardial ischemia in patients with stroke. These findings indicate that the prevalence of asymptomatic myocardial ischemia is relatively high, especially in patients with stroke of atherosclerotic origin. Therefore, it is beneficial for us to narrow the target population who are at the highest risk when screening for SMI in Japanese patients with acute cerebral infarction. PMID:22124530

  5. Quantitative assessment of myocardial perfusion using dynamic three-dimensional x-ray computed angiography

    SciTech Connect

    Teslow, T.N.

    1985-01-01

    Using computed tomogram time series, myocardial perfusion was angiographically measured as distributions of x-ray circulatory indicators in three dimensions. By separating the dynamic function from the cardiac structure, these separate components were tested using region-of-interest (ROI) mensuration in simulation, phantom, and in vivo experiments. Statistical criteria were used to evaluate the dynamic component which was represented by analytic mathematical models of indicator dilution. The spatial component was represented by three-dimensional (3-D) and two-dimensional (2-D) geometric models of the heart. Each of these components were determined in individual ROI's and globally integrated to manifest the perfusion heterogeneities. A physical heart phantom with controllable regional perfusion characteristics was also developed and studied. Experiments conducted on dogs compared the accuracy of 2-D and 3-D perfusion measurements by imaging to those using gamma-radioactive microspheres. Accurate reproducible localization of the heart was found to be important for obtaining accurate measures of regional perfusion in 3-D volume images exhibiting high noise.

  6. In vivo assessment of myocardial perfusion and viability by kinetics of potassium-38

    SciTech Connect

    Bol, A.; Melin, J.A.; Wijns, W.

    1994-05-01

    To assess whether myocardial perfusion and viability could be estimated by dynamic K-38 (T1/2: 8 min) imaging with Positron Emission Tomography, closed chest dogs were studied after permanent (PERM; 8 studies) or during transient (TRANS; 7 studies) circumflex coronary occlusion. By using a two-compartment kinetic model, estimates of PET myocardial perfusion were compared to in vitro labeled microspheres (MS) myocardial blood flow (MBF; ml/min/100g). The backward rate of transport (k2) was also derived as a putative index of viability. Triphenyl tetrazolium chloride (TTC) staining was used to identify necrosis (TTC-) or viable tissue (TTC+). In the risk zone, MS-MBF ranged from 2 to 143 in 17 TTC- regions and from 6 to 48 in 12 TTC+ regions; K-38 MBF estimates correlated well with MS-MBF both in TTC- regions (MS-MBF : 37{plus_minus}43; y=1+1.2x; r=0.97) of PERM studies and in TTC+ regions (MS-MBF :28{plus_minus}13; y=7+0.69x; r=0.79) of TRANS studies. The backward rate of transport, k2 (min{sup -1}), was increased in 7/17 TTC-regions (5{plus_minus}8; n=17) and in none of the TTC+ regions (0.1{plus_minus}0.1). Thus, during experimental coronary occlusion, potassium-38 dynamic imaging provides a valuable estimate of absolute myocardial perfusion in low flow regions. Moreover, potassium-38 backdiffusion assessed by k2 might be a promising index of necrosis.

  7. Combined assessment of thrombolysis in myocardial infarction flow grade, myocardial perfusion grade, and ST-segment resolution to evaluate epicardial and myocardial reperfusion.

    PubMed

    Giugliano, Robert P; Sabatine, Marc S; Gibson, C Michael; Roe, Matthew T; Harrington, Robert A; Murphy, Sabina A; Morrow, David A; Antman, Elliott M; Braunwald, Eugene

    2004-06-01

    The restoration of epicardial and myocardial flow remains the primary goal of reperfusion therapy in patients with ST-segment elevation myocardial infarction, but the optimal method to assess this goal has not been defined. Thrombolysis In Myocardial Infarction flow grade (TFG), myocardial perfusion grade (MPG), and ST-segment resolution (STRes) were combined to formulate a new measure of successful reperfusion in 649 patients who received pharmacologic reperfusion therapy in 3 recent phase II clinical trials of ST-segment elevation myocardial infarction. Coronary angiograms and electrocardiograms were analyzed at 60 minutes (before any intervention) after the initiation of reperfusion therapy. The complete restoration of perfusion, or the "trifecta," defined as the presence of TFG 3, MPG 3, and complete (> or =70%) STRes, occurred in 117 patients (18%). The achievement of this trifecta was associated with low rates of 30-day mortality (0% vs 3.9%, p = 0.02), congestive heart failure (CHF) (0.9% vs 7.1%, p = 0.01), and the combination of death or CHF (0.9% vs 10.7%, p = 0.001). When the results were stratified with respect to subsequent percutaneous coronary intervention (PCI) from 60 to 120 minutes, attainment of the trifecta at 60 minutes remained a strong predictor of better clinical outcomes, particularly in those patients who underwent early PCI. The achievement of TFG 3, MPG 3, and complete STRes at 60 minutes after fibrinolytic therapy and before PCI occurred in only 18% of patients but was associated with very low rates of death and CHF at 30 days. This new end point is proposed to evaluate the success of reperfusion therapy in patients who undergo early angiography. PMID:15165915

  8. Clinical decision making with myocardial perfusion imaging in patients with known or suspected coronary artery disease.

    PubMed

    Cremer, Paul; Hachamovitch, Rory; Tamarappoo, Balaji

    2014-07-01

    Myocardial perfusion imaging (MPI) to diagnose coronary artery disease (CAD) is best performed in patients with intermediate pretest likelihood of disease; unfortunately, pretest likelihood is often overestimated, resulting in the inappropriate use of perfusion imaging. A good functional capacity often predicts low risk, and MPI for diagnosing CAD should be reserved for individuals with poor exercise capacity, abnormal resting electrocardiography, or an intermediate or high probability of CAD. With respect to anatomy-based testing, coronary CT angiography has a good negative predictive value, but stenosis severity correlates poorly with ischemia. Therefore decision making with respect to revascularization may be limited when a purely noninvasive anatomical test is used. Regarding perfusion imaging, the diagnostic accuracies of SPECT, PET, and cardiac magnetic resonance are similar, though fewer studies are available with cardiac magnetic resonance. PET coronary flow reserve may offer a negative predictive value sufficiently high to exclude severe CAD such that patients with mild to moderate reversible perfusion defects can forego invasive angiography. In addition, combined anatomical and perfusion-based imaging may eventually offer a definitive evaluation for diagnosing CAD, even in higher risk patients. Any remarkable findings on single-photon emission computed tomography and PET MPI studies are valuable for prognostication. Furthermore, assessment of myocardial blood flow with PET is particularly powerful for prognostication as it reflects the end result of many processes that lead to atherosclerosis. Decision making with respect to revascularization is limited for cardiac MRI and PET MPI. In contrast, retrospective radionuclide studies have identified an ischemic threshold, but randomized trials are needed. In patients with at least moderately reduced left ventricular systolic function, viable myocardium as assessed by PET or MRI, appears to identify patients

  9. 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

  10. Correlation of myocardial perfusion SPECT with invasive and computed tomography coronary angiogram

    PubMed Central

    Shelley, S.; Indirani, M.; Sathyamurthy, I.; Subramanian, K.; Priti, N.; Harshad, K.; Padma, D.

    2012-01-01

    Background The consequences of atherosclerosis can be detected by multislice computed tomography (MSCT), invasive coronary angiogram (CAG) and the resultant myocardial ischaemia by myocardial perfusion single photon emission computed tomography (MPS). In this study an attempt is made to compare MSCT with MPS and also to compare the MSCT findings with that of invasive CAG in patients suspected to have coronary artery disease (CAD). Materials and methods A total of 99 patients suspected to have CAD underwent both MSCT and MPS with 99mTc sestamibi. The MSCT studies were classified as having no CAD, significant CAD (>50% diameter stenosis), and insignificant CAD (<50% diameter stenosis). Myocardial perfusion single photon emission computed tomography was reported as normal and reversible ischaemia. In a subgroup of 33 patient invasive CAG was done. Results In 99 patients, 396 coronaries were evaluated with MSCT and MPS. Coronary artery calcium scoring (CACS) in these patient ranged from 0 to 2200. No CAD was noted in 128 (32%) coronaries but MPS was found abnormal in 9 (7%) coronaries. Insignificant CAD was noted in 169 (43%) coronaries amongst which reversible ischaemia was noted in 23 (14%). Significant CAD was noted in 99 (25%) coronaries of which only 54 (55%) were MPS positive for reversible ischaemia. The MSCT has a negative predictive value (NPV) of 97%. When MSCT was normal, MPS was almost normal, but the reverse was not true. That is when MPS was normal MSCT was not always normal but showed lesion of insignificant obstruction. In the subset of 33 patients, who underwent invasive angiogram, 132 coronaries were evaluated. Coronary angiogram showed 48 coronaries (36%) to have significant CAD (>50% diameter stenosis). Multislice computed tomography correlated well in 46 (84%) with P value of <0.001 (χ2-test) but for 9 (16%) showing overestimation due to increased CACS (>800). Myocardial perfusion single photon emission computed tomography was normal in 15 (27

  11. Do thallium myocardial perfusion scan abnormalities predict survival in sarcoid patients without cardiac symptoms

    SciTech Connect

    Kinney, E.L.; Caldwell, J.W. )

    1990-07-01

    Whereas the total mortality rate for sarcoidosis is 0.2 per 100,000, the prognosis, when the heart is involved, is very much worse. The authors used the difference in mortality rate to infer whether thallium 201 myocardial perfusion scan abnormalities correspond to myocardial sarcoid by making the simplifying assumption that if they do, then patients with abnormal scans will be found to have a death rate similar to patients with sarcoid heart disease. The authors therefore analyzed complete survival data on 52 sarcoid patients without cardiac symptoms an average of eighty-nine months after they had been scanned as part of a protocol. By use of survival analysis (the Cox proportional hazards model), the only variable that was significantly associated with survival was age. The patients' scan pattern, treatment status, gender, and race were not significantly related to survival. The authors conclude that thallium myocardial perfusion scans cannot reliably be used to diagnose sarcoid heart disease in sarcoid patients without cardiac symptoms.

  12. Evaluation of mechanical dyssynchrony and myocardial perfusion using phase analysis of gated SPECT imaging in patients with left ventricular dysfunction

    PubMed Central

    Trimble, Mark A.; Borges-Neto, Salvador; Honeycutt, Emily F.; Shaw, Linda K.; Pagnanelli, Robert; Chen, Ji; Iskandrian, Ami E.; Garcia, Ernest V.; Velazquez, Eric J.

    2010-01-01

    Background Using phase analysis of gated single photon emission computed tomography (SPECT) imaging, we examined the relation between myocardial perfusion, degree of electrical dyssynchrony, and degree of SPECT-derived mechanical dyssynchrony in patients with left ventricular (LV) dysfunction. Methods and Results We retrospectively examined 125 patients with LV dysfunction and ejection fraction of 35% or lower. Fourier analysis converts regional myocardial counts into a continuous thickening function, allowing resolution of phase of onset of myocardial thickening. The SD of LV phase distribution (phase SD) and histogram bandwidth describe LV phase dispersion as a measure of dyssynchrony. Heart failure (HF) patients with perfusion abnormalities ities have higher degrees of dyssynchrony measured by median phase SD (45.5° vs 27.7°, P < .0001) and bandwidth (117.0° vs 73.0°, P = .0006). HF patients with prolonged QRS durations have higher degrees of dyssynchrony measured by median phase SD (54.1° vs 34.7°, P < .0001) and bandwidth (136.5° vs 99.0°, P = .0005). Mild to moderate correlations exist between QRS duration and phase analysis indices of phase SD (r = 0.50) and bandwidth (r = 0.40). Mechanical dyssynchrony (phase SD >43°) was 43.2%. Conclusions HF patients with perfusion abnormalities or prolonged QRS durations QRS durations have higher degrees of mechanical dyssynchrony. Gated SPECT myocardial perfusion imaging can quantify myocardial function, perfusion, and dyssynchrony and may help in evaluating patients for cardiac resynchronization therapy. PMID:18761269

  13. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    SciTech Connect

    Tao, Yinghua; Chen, Guang-Hong; Hacker, Timothy A.; Raval, Amish N.; Van Lysel, Michael S.; Speidel, Michael A.

    2014-07-15

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  14. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    PubMed Central

    Tao, Yinghua; Chen, Guang-Hong; Hacker, Timothy A.; Raval, Amish N.; Van Lysel, Michael S.; Speidel, Michael A.

    2014-01-01

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  15. 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.

  16. Radiation dose to radiosensitive organs in PET/CT myocardial perfusion examination using versatile optical fibre

    NASA Astrophysics Data System (ADS)

    Salasiah, M.; Nordin, A. J.; Fathinul Fikri, A. S.; Hishar, H.; Tamchek, N.; Taiman, K.; Ahmad Bazli, A. K.; Abdul-Rashid, H. A.; Mahdiraji, G. A.; Mizanur, R.; Noor, Noramaliza M.

    2013-05-01

    Cardiac positron emission tomography (PET) provides a precise method in order to diagnose obstructive coronary artery disease (CAD), compared to single photon emission tomography (SPECT). PET is suitable for obese and patients who underwent pharmacologic stress procedures. It has the ability to evaluate multivessel coronary artery disease by recording changes in left ventricular function from rest to peak stress and quantifying myocardial perfusion (in mL/min/g of tissue). However, the radiation dose to the radiosensitive organs has become crucial issues in the Positron Emission Tomography/Computed Tomography(PET/CT) scanning procedure. The objective of this study was to estimate radiation dose to radiosensitive organs of patients who underwent PET/CT myocardial perfusion examination at Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia in one month period using versatile optical fibres (Ge-B-doped Flat Fibre) and LiF (TLD-100 chips). All stress and rest paired myocardial perfusion PET/CT scans will be performed with the use of Rubidium-82 (82Rb). The optic fibres were loaded into plastic capsules and attached to patient's eyes, thyroid and breasts prior to the infusion of 82Rb, to accommodate the ten cases for the rest and stress PET scans. The results were compared with established thermoluminescence material, TLD-100 chips. The result shows that radiation dose given by TLD-100 and Germanium-Boron-doped Flat Fiber (Ge-B-doped Flat Fiber) for these five organs were comparable to each other where the p>0.05. For CT scans,thyroid received the highest dose compared to other organs. Meanwhile, for PET scans, breasts received the highest dose.

  17. A novel gallium bisaminothiolate complex as a myocardial perfusion imaging agent

    PubMed Central

    Plössl, Karl; Chandra, Rajesh; Qu, Wenchao; Lieberman, Brian P.; Kung, Mei-Ping; Zhou, Rong; Huang, Bin; Kung, Hank F.

    2010-01-01

    The development of new myocardial perfusion imaging agents for positron emission tomography (PET) may improve the resolution and quantitation of changes in regional myocardial perfusion measurement. It is known that a 68Ge/68Ga generator can provide a convenient source of PET tracers because of the long physical half-life of 68Ge (271 days). A new ligand, 7,8-dithia-16,24-diaza-trispiro[5.2.5.2.5.3] pentacosa-15,24-diene, which consists of a N2S2-chelating core incorporated into three cyclohexyl rings, was prepared. To test feasibility and potential utility, the N2S2 ligand was successfully labeled and tested with 67Ga (half-life=3.26 day; γ=93.3, 184.6 and 300.2 keV), which showed >92% radiochemical purity. The corresponding “cold” Ga complex was synthesized, and its structure containing a pyramidal N2S2 chloride core was elucidated with X-ray crystallography. In vivo biodistribution of this novel 67Ga complex, evaluated in normal rats, exhibited excellent heart uptake and retention, with 2.1% and 0.9% initial dose/organ at 2 and 60 min, respectively, after an intravenous injection. Autoradiography was performed in normal rats and in rats that had the left anterior descending coronary artery permanently ligated surgically. Autoradiography showed an even uptake of activity in the normal heart, and there was a distinctively lower uptake in the damaged side of the surgically modified heart. In conclusion, the new N2S2 ligand was readily prepared and labeled with radioactive 67Ga. Biodistribution in rats revealed high initial heart uptake and relatively high retention reflecting regional myocardial perfusion. PMID:18158947

  18. Synthesis of fluorine-18 labeled rhodamine B: A potential PET myocardial perfusion imaging agent

    PubMed Central

    Heinrich, Tobias K.; Gottumukkala, Vijay; Snay, Erin; Dunning, Patricia; Fahey, Frederic H; Treves, S. Ted; Packard, Alan B.

    2009-01-01

    There is considerable interest in developing an 18F-labeled PET myocardial perfusion agent. Rhodamine dyes share several properties with 99mTc-MIBI, the most commonly used single-photon myocardial perfusion agent, suggesting that an 18F-labeled rhodamine dye might prove useful for this application. In addition to being lipophilic cations, like 99mTc-MIBI, rhodamine dyes are known to accumulate in the myocardium and are substrates for Pgp, the protein implicated in MDR1 multidrug resistance. As the first step in determining whether 18F-labeled rhodamines might be useful as myocardial perfusion agents for PET, our objective was to develop synthetic methods for preparing the 18F-labeled compounds so that they could be evaluated in vivo. Rhodamine B was chosen as the prototype compound for development of the synthesis because the ethyl substituents on the amine moieties of rhodamine B protect them from side reactions, thus eliminating the need to include (and subsequently remove) protecting groups. The 2′-[18F]fluoroethyl ester of rhodamine B was synthesized by heating rhodamine B lactone with [18F]fluoroethyltosylate in acetonitrile at 165°C for 30 min.using [18F]fluoroethyl tosylate, which was prepared by the reaction of ethyleneglycol ditosylate with Kryptofix 2.2.2, K2CO3, and [18F]NaF in acetonitrile for 10 min. at 90°C. The product was purified by semi-preparative HPLC to produce the 2′-[18F]-fluoroethylester in >97% radiochemical purity with a specific activity of 1.3 GBq/μmol, an isolated decay corrected yield of 35%, and a total synthesis time of 90 min. PMID:19783150

  19. 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.

  20. Optimization of Rb-82 PET acquisition and reconstruction protocols for myocardial perfusion defect detection

    NASA Astrophysics Data System (ADS)

    Tang, Jing; Rahmim, Arman; Lautamäki, Riikka; Lodge, Martin A.; Bengel, Frank M.; Tsui, Benjamin M. W.

    2009-05-01

    The purpose of this study is to optimize the dynamic Rb-82 cardiac PET acquisition and reconstruction protocols for maximum myocardial perfusion defect detection using realistic simulation data and task-based evaluation. Time activity curves (TACs) of different organs under both rest and stress conditions were extracted from dynamic Rb-82 PET images of five normal patients. Combined SimSET-GATE Monte Carlo simulation was used to generate nearly noise-free cardiac PET data from a time series of 3D NCAT phantoms with organ activities modeling different pre-scan delay times (PDTs) and total acquisition times (TATs). Poisson noise was added to the nearly noise-free projections and the OS-EM algorithm was applied to generate noisy reconstructed images. The channelized Hotelling observer (CHO) with 32× 32 spatial templates corresponding to four octave-wide frequency channels was used to evaluate the images. The area under the ROC curve (AUC) was calculated from the CHO rating data as an index for image quality in terms of myocardial perfusion defect detection. The 0.5 cycle cm-1 Butterworth post-filtering on OS-EM (with 21 subsets) reconstructed images generates the highest AUC values while those from iteration numbers 1 to 4 do not show different AUC values. The optimized PDTs for both rest and stress conditions are found to be close to the cross points of the left ventricular chamber and myocardium TACs, which may promote an individualized PDT for patient data processing and image reconstruction. Shortening the TATs for <~3 min from the clinically employed acquisition time does not affect the myocardial perfusion defect detection significantly for both rest and stress studies.

  1. Assessment of the myocardial perfusion pattern in patients with multivessel coronary artery disease

    SciTech Connect

    Iskandrian, A.S.; Hakki, A.H.; Segal, B.L.; Kane, S.A.; Amenta, A.

    1983-11-01

    A total of 42 symptomatic patients with coronary artery disease involving two or three vessels were studied using exercise thallium-201 myocardial scintigraphy. Qualitative analysis of the images predicted multivessel disease in 75% of the patients with two-vessel disease and in 82% of the patients with three-vessel disease. Quantitative analysis of the size of the perfusion defect indicated that approximately 40% of the left ventricular perimeter showed abnormal perfusion pattern during stress in these patients, and there was no significant difference in the size of the defect in patients with two-vessel disease or three-vessel disease (41 +/- 17% vs 42 +/- 14%, respectively, mean +/- SD). The exercise heart rate, exercise ECG response, and severity of narrowing did not correlate with the size of the perfusion defect. Patients with anterior infarction had larger defects in the distribution of the left anterior descending artery than those without infarction. Collaterals offered partial protection during exercise only when they were not jeopardized. This study confirms the value of qualitative analysis of exercise thallium-201 imaging in predicting multivessel disease, and describes a simple method of assessing the extent of perfusion abnormalities during stress in patients with multivessel disease. The results may be important in patient management and prognosis.

  2. Large abdominal photopenic area on 99mTc-sestamibi myocardial perfusion imaging.

    PubMed

    Lyon, Jennifer; Spaulding, John; Zack, Paul M

    2012-12-01

    (99m)Tc-sestamibi myocardial perfusion imaging is frequently performed in conjunction with exercise or pharmacologic stress testing for evaluation of coronary heart disease. Interpretation of these studies includes systematic review of unprocessed rotating projectional images for evaluation of cardiac size as well as the presence of motion or attenuation artifacts. Occasionally, incidental noncardiac findings are detected on review of the projectional images. We report a case of a patient with a history of autosomal dominant polycystic kidney disease who was found to have a large abdominal photopenic area on the projectional images. The photopenic area corresponded to the location of large intraabdominal cysts on abdominal CT and was consistent with hepatic cysts associated with the patient's known polycystic kidney disease. We review the differential diagnosis of large abdominal photopenic regions identified on myocardial projectional images and the importance of routinely analyzing these images for incidental noncardiac findings. PMID:22997275

  3. Factors in myocardial "perfusion" imaging with ultrafast MRI and Gd-DTPA administration.

    PubMed

    Burstein, D; Taratuta, E; Manning, W J

    1991-08-01

    Ultrafast magnetic resonance imaging (MRI) and first pass observation of an interstitial contrast agent are currently being used to study myocardial perfusion. Image intensity, however, is a function of several parameters, including the delivery of the contrast agent to the interstitium (coronary flow rate and diffusion into the interstitium) and the relaxation properties of the tissue (contrast agent concentration, proton exchange rates, and relative intra- and extracellular volume fractions). In this study, image intensity during gadopentetate dimeglumine (Gd-DTPA) administration with T1-weighted ultrafast MR imaging was assessed in an isolated heart preparation. With increasing Gd-DTPA concentration, the steady-state myocardial image intensity increased but the time to reach steady state remained unchanged, resulting in an increased slope of image intensity change. A range of physiologic perfusion pressures (and resulting coronary flow rates) had insignificant effects on kinetics of Gd-DTPA wash-in or steady-state image intensity, suggesting that diffusion of Gd-DTPA into the interstitium is the rate limiting step in image intensity change with this preparation. Following global ischemia and reperfusion, transmural differences in the slope of image intensity change were apparent. However, the altered steady-state image intensity (due to postischemic edema) makes interpretation of this finding difficult. The studies described here demonstrate that although Gd-DTPA administration combined with ultrafast imaging may be a sensitive indicator of perfusion abnormalities, factors other than perfusion will affect image intensity. Extensive studies will be required before image intensity with this protocol is fully understood. PMID:1775055

  4. Segmentation of the Left Ventricle in Myocardial Perfusion SPECT Using Active Shape Model

    NASA Astrophysics Data System (ADS)

    Tan, Wooi-Haw; Besar, Rosli

    In the quantification of myocardial perfusion SPECT (MPS), numerous processes are involved. Automation is desired as it will considerably reduce the laboriousness of the underlying tasks. In this paper, we propose a segmentation scheme for the delineation of left ventricle (LV) using the Active Shape Models. Our scheme will reduce the labour-intensiveness in MPS quantification, while still allowing interactive guidance from the medical experts. The proposed scheme has been applied on clinical MPS tomograms in which it has successfully delineated the LV in 94% of the test data. In addition, it has also shown to be more suitable for LV segmentation than the rivaling Active Contour Model.

  5. Clinical benefit of adenosine as an adjunct to reperfusion in ST-elevation myocardial infarction patients: An updated meta-analysis of randomized controlled trials

    PubMed Central

    Bulluck, Heerajnarain; Sirker, Alex; Loke, Yoon K.; Garcia-Dorado, David; Hausenloy, Derek J.

    2016-01-01

    Background Adenosine administered as an adjunct to reperfusion can reduce coronary no-reflow and limit myocardial infarct (MI) size in ST-segment elevation myocardial infarction (STEMI) patients. Whether adjunctive adenosine therapy can improve clinical outcomes in reperfused STEMI patients is not clear and is investigated in this meta-analysis of 13 randomized controlled trials (RCTs). Methods We performed an up-to-date search for all RCTs investigating adenosine as an adjunct to reperfusion in STEMI patients. We calculated pooled relative risks using a fixed-effect meta-analysis assessing the impact of adjunctive adenosine therapy on major clinical endpoint including all-cause mortality, non-fatal myocardial infarction, and heart failure. Surrogate markers of reperfusion were also analyzed. Results 13 RCTs (4273 STEMI patients) were identified and divided into 2 subgroups: intracoronary adenosine versus control (8 RCTs) and intravenous adenosine versus control (5 RCTs). In patients administered intracoronary adenosine, the incidence of heart failure was significantly lower (risk ratio [RR] 0.44 [95% CI 0.25–0.78], P = 0.005) and the incidence of coronary no-reflow was reduced (RR for TIMI flow<3 postreperfusion 0.68 [95% CI 0.47–0.99], P = 0.04). There was no difference in heart failure incidence in the intravenous adenosine group but most RCTs in this subgroup were from the thrombolysis era. There was no difference in non-fatal MI or all-cause mortality in both subgroups. Conclusion We find evidence of improved clinical outcome in terms of less heart failure in STEMI patients administered intracoronary adenosine as an adjunct to reperfusion. This finding will need to be confirmed in a large adequately powered prospective RCT. PMID:26402450

  6. Clinical experience with technetium-99m teboroxime, a neutral, lipophilic myocardial perfusion imaging agent

    SciTech Connect

    Johnson, L.L.; Seldin, D.W. )

    1990-10-16

    Technetium-99m (Tc-99m) teboroxime is a new technetium-based myocardial perfusion imaging agent (investigational code = SQ30217 (Cardiotec, Squibb Diagnostics)). A member of a class of neutral, lipophilic, technetium-containing complexes known as boronic acid adducts of technetium dioxime (BATO) complexes, this agent is chemically very different from the cationic tracer thallium-201 (Tl-201) and from the cationic technetium complex Tc-99m sestamibi (Cardiolite, Du Pont Imaging Agents). Tc-99m teboroxime has high myocardial extraction, rapid blood clearance, little lung uptake and rapid myocardial washout. A biexponential pattern of myocardial washout is demonstrated in animals and in man. Effective half-lives of the 2 washout components in man are 5.2 minutes and 3.8 hours and represent approximately 66 and 33% of the myocardial activity, respectively. The first half-life for the myocardium is approximately 11 minutes. As the agent washes out of the heart, hepatic uptake occurs, peaking at about 5 minutes after injection. The liver is the major organ of excretion and receives, along with the large bowel, the largest radiation dose. Rapid imaging protocols using standard cameras have achieved good myocardial counts from 3 planar views acquired over a 4- to 5-minute period or for single photon emission computed tomography (SPECT) images acquired over a 10-minute period. An entire stress/rest procedure can be completed in 1 hour. Analysis of data from 155 patients from 4 centers using planar or SPECT imaging showed a sensitivity and specificity for blinded readings of 82 and 91%, respectively, when compared against overall clinical impression. 13 references.

  7. Non-ECG-Gated Myocardial Perfusion MRI Using Continuous Magnetization-Driven Radial Sampling

    PubMed Central

    Sharif, Behzad; Dharmakumar, Rohan; Arsanjani, Reza; Thomson, Louise; Merz, C. Noel Bairey; Berman, Daniel S.; Li, Debiao

    2014-01-01

    Purpose Establishing a high-resolution non-ECG-gated first-pass perfusion (FPP) cardiac MRI technique may improve accessibility and diagnostic capability of FPP imaging. We propose a non-ECG-gated FPP imaging technique using continuous magnetization-driven golden-angle radial acquisition. The main purpose of this preliminary study is to evaluate whether, in the simple case of single-slice 2D imaging, adequate myocardial contrast can be obtained for accurate visualization of hypoperfused territories in the setting of myocardial ischemia. Methods A T1-weighted pulse sequence with continuous golden-angle radial sampling was developed for non-ECG-gated FPP imaging. A sliding-window scheme with no temporal acceleration was used to reconstruct 8 frames/second. Canines were imaged at 3T with and without coronary stenosis using the proposed scheme and a conventional magnetization-prepared ECG-gated FPP method. Results Our studies showed that the proposed non-ECG-gated method is capable of generating high-resolution (1.7×1.7×6 mm3) artifact-free FPP images of a single slice at high heart rates (92±21 beats/minute), while matching the performance of conventional FPP imaging in terms of hypoperfused-to-normal myocardial contrast-to-noise ratio (proposed: 5.18±0.70, conventional: 4.88±0.43). Furthermore, the detected perfusion defect areas were consistent with the conventional FPP images. Conclusion Non-ECG-gated FPP imaging using optimized continuous golden-angle radial acquisition achieves desirable image quality (i.e., adequate myocardial contrast, high spatial resolution, and minimal artifacts) in the setting of ischemia. PMID:24443160

  8. Prediction of Flow-Limiting Fractional Flow Reserve in Patients With Stable Coronary Artery Disease Based on Quantitative Myocardial Perfusion Imaging.

    PubMed

    Tanaka, Haruki; Takahashi, Teruyuki; Kozono, Nami; Tanakamaru, Yoshiki; Ohashi, Norihiko; Yasunobu, Yuji; Tanaka, Koichi; Okada, Takenori; Kaseda, Shunichi; Nakanishi, Toshio; Kihara, Yasuki

    2016-05-01

    Although fractional flow reserve (FFR) and myocardial perfusion imaging (MPI) findings fundamentally differ, several cohort studies have revealed that these findings correlate. Here, we investigated whether flow-limiting FFR could be predicted from adenosine stress thallium-201 MPI with single-photon emission computed tomography (SPECT) findings derived from 84 consecutive, prospectively identified patients with stable coronary artery disease and 212 diseased vessels. Among them, FFR was measured in 136 diseased vessels (64%). The findings were compared with regional perfusion abnormalities including stress total perfusion defect (TPD) - rest TPD determined using quantitative perfusion single-photon emission computed tomography software. The FFR inversely correlated the most accurately with stress TPD - rest TPD (r = -0.552, p <0.001). Predictors of major vessels of interest comprising FFR <0.80, included stress TPD - rest TPD, the transient ischemic dilation ratio, left ventricular ejection fraction at rest and beta blockers for left anterior descending artery (LAD) regions, and stress TPD - rest TPD, left ventricular mass, left ventricular ejection fraction at rest, right coronary artery lesions, the transient ischemic dilation ratio, and age for non-LAD regions. The diagnostic accuracy of formulas to predict major vessels of interest with FFR <0.80 was high (sensitivity, specificity and accuracy for LAD and non-LAD: 84%, 87% and 86%, and 75%, 93% and 87%, respectively). In conclusion, although somewhat limited by a sample size and a single-center design, flow-limiting FFR could be predicted from MPI findings with a defined probability. A cohort study might validate our results and provide a novel adjunctive tool with which to diagnose functionally significant coronary artery disease from MPI findings. PMID:26970815

  9. Adenosine-induced coronary vasospasm following drug-eluting stent implantation

    PubMed Central

    Matsumoto, Naoya; Nagao, Ken; Hirayama, Atsushi; Kasama, Shu

    2014-01-01

    We present the case of coronary vasospasm during adenosine stress in a patient with a prior drug-eluting stent implantation. The patient had a stent implantation in the left anterior descending coronary artery 3 years ago. Recently, he developed a chest pain and underwent adenosine stress myocardial perfusion single photon emission CT (SPECT). During the adenosine stress, he felt severe chest pain and ST elevation on electrocardiogram. An invasive coronary angiography showed no in-stent restenosis. This phenomenon deemed to be adenosine-induced coronary vasospasm after stent implantation. PMID:24518394

  10. Myocardial perfusion as assessed by thallium-201 scintigraphy during the discontinuation of mechanical ventilation in ventilator-dependent patients

    SciTech Connect

    Hurford, W.E.; Lynch, K.E.; Strauss, H.W.; Lowenstein, E.; Zapol, W.M. )

    1991-06-01

    Patients who cannot be separated from mechanical ventilation (MV) after an episode of acute respiratory failure often have coexisting coronary artery disease. The authors hypothesized that increased left ventricular (LV) wall stress during periods of spontaneous ventilation (SV) could alter myocardial perfusion in these patients. Using thallium-201 (201TI) myocardial scintigraphy, the authors studied the occurrence of myocardial perfusion abnormalities during periods of SV in 15 MV-dependent patients (nine women, six men; aged 71 {plus minus} 7 yr, mean {plus minus} SD). Fourteen of these patients were studied once with 201TI myocardial scintigraphy during intermittent mechanical ventilation (IMV) and again on another day, after at least 10 min of SV through a T-piece. One patient was studied during SV only. Thirteen of 14 of the patients (93%) studied during MV had abnormal patterns of initial myocardial 201TI uptake, but only 1 patient demonstrated redistribution of 201TI on delayed images. The remainder of the abnormalities observed during MV were fixed defects. SV produced significant alterations of myocardial 201TI distribution or transient LV dilation, or both, in 7 of the 15 patients (47%). Four patients demonstrated new regional decreases of LV myocardial thallium concentration with redistribution of the isotope on delayed images. The patient studied only during SV also had myocardial 201TI defects with redistribution. Five patients (3 also having areas of 201TI redistribution) had transient LV dilation during SV.

  11. Myocardial Perfusion SPECT Imaging in Dextrocardia with Situs Inversus: A Case Report

    PubMed Central

    Ayeni, Olusegun Akinwale; Malan, Nico; Hammond, Emmanuel Niiboye; Vangu, Mboyo-Di-Tamba Heben

    2016-01-01

    Dextrocardia is a cardiac positional anomaly in which the heart is located in the right hemithorax with its base-to-apex axis directed to the right and caudad. Situs inversus is an autosomal recessive disorder that causes organs in the chest and abdomen to be positioned in a mirror image from their normal position. Dextrocardia may occur in isolation or as part of situs inversus. Similarly, situs inversus may occur with or without dextrocardia. Situs inversus accompanied with dextrocardia (situs inversus totalis) is a rare congenital abnormality occurring in 0.01% of live births. Herein, we present the case of a 35-year-old man with previously diagnosed situs inversus totalis with mirror-image dextrocardia, referred to our facility for diagnosis of coronary artery disease (CAD). The incidence and presentation of CAD in patients with dextrocardia are similar to the normal population. However, considerable attention should be paid to the acquisition of myocardial perfusion scintigraphy and data processing/analysis in this group of patients. The present case highlights the distinctive applications and potential pitfalls of myocardial perfusion single-photon emission computed tomography (SPECT) imaging in patients with dextrocardia. PMID:27408900

  12. Robust dynamic myocardial perfusion CT deconvolution using adaptive-weighted tensor total variation regularization

    NASA Astrophysics Data System (ADS)

    Gong, Changfei; Zeng, Dong; Bian, Zhaoying; Huang, Jing; Zhang, Xinyu; Zhang, Hua; Lu, Lijun; Feng, Qianjin; Liang, Zhengrong; Ma, Jianhua

    2016-03-01

    Dynamic myocardial perfusion computed tomography (MPCT) is a promising technique for diagnosis and risk stratification of coronary artery disease by assessing the myocardial perfusion hemodynamic maps (MPHM). Meanwhile, the repeated scanning of the same region results in a relatively large radiation dose to patients potentially. In this work, we present a robust MPCT deconvolution algorithm with adaptive-weighted tensor total variation regularization to estimate residue function accurately under the low-dose context, which is termed `MPD-AwTTV'. More specifically, the AwTTV regularization takes into account the anisotropic edge property of the MPCT images compared with the conventional total variation (TV) regularization, which can mitigate the drawbacks of TV regularization. Subsequently, an effective iterative algorithm was adopted to minimize the associative objective function. Experimental results on a modified XCAT phantom demonstrated that the present MPD-AwTTV algorithm outperforms and is superior to other existing deconvolution algorithms in terms of noise-induced artifacts suppression, edge details preservation and accurate MPHM estimation.

  13. A 3D aligned microfibrous myocardial tissue construct cultured under transient perfusion.

    PubMed

    Kenar, Halime; Kose, Gamze T; Toner, Mehmet; Kaplan, David L; Hasirci, Vasif

    2011-08-01

    The goal of this study was to design and develop a myocardial patch to use in the repair of myocardial infarctions or to slow down tissue damage and improve long-term heart function. The basic 3D construct design involved two biodegradable macroporous tubes, to allow transport of growth media to the cells within the construct, and cell seeded, aligned fiber mats wrapped around them. The microfibrous mat housed mesenchymal stem cells (MSCs) from human umbilical cord matrix (Wharton's Jelly) aligned in parallel to each other in a similar way to cell organization in native myocardium. Aligned micron-sized fiber mats were obtained by electrospinning a polyester blend (PHBV (5% HV), P(L-D,L)LA (70:30) and poly(glycerol sebacate) (PGS)). The micron-sized electrospun parallel fibers were effective in Wharton's Jelly (WJ) MSCs alignment and the cells were able to retract the mat. The 3D construct was cultured in a microbioreactor by perfusing the growth media transiently through the macroporous tubing for two weeks and examined by fluorescence microscopy for cell distribution and preservation of alignment. The fluorescence images of thin sections of 3D constructs from static and perfused cultures confirmed enhanced cell viability, uniform cell distribution and alignment due to nutrient provision from inside the 3D structure. PMID:21570112

  14. Myocardial Perfusion SPECT Imaging in Dextrocardia with Situs Inversus: A Case Report.

    PubMed

    Ayeni, Olusegun Akinwale; Malan, Nico; Hammond, Emmanuel Niiboye; Vangu, Mboyo-Di-Tamba Heben

    2016-01-01

    Dextrocardia is a cardiac positional anomaly in which the heart is located in the right hemithorax with its base-to-apex axis directed to the right and caudad. Situs inversus is an autosomal recessive disorder that causes organs in the chest and abdomen to be positioned in a mirror image from their normal position. Dextrocardia may occur in isolation or as part of situs inversus. Similarly, situs inversus may occur with or without dextrocardia. Situs inversus accompanied with dextrocardia (situs inversus totalis) is a rare congenital abnormality occurring in 0.01% of live births. Herein, we present the case of a 35-year-old man with previously diagnosed situs inversus totalis with mirror-image dextrocardia, referred to our facility for diagnosis of coronary artery disease (CAD). The incidence and presentation of CAD in patients with dextrocardia are similar to the normal population. However, considerable attention should be paid to the acquisition of myocardial perfusion scintigraphy and data processing/analysis in this group of patients. The present case highlights the distinctive applications and potential pitfalls of myocardial perfusion single-photon emission computed tomography (SPECT) imaging in patients with dextrocardia. PMID:27408900

  15. Novel Cadmium Zinc Telluride Devices for Myocardial Perfusion Imaging-Technological Aspects and Clinical Applications.

    PubMed

    Ben-Haim, Simona; Kennedy, John; Keidar, Zohar

    2016-07-01

    Myocardial perfusion imaging plays an important role in the assessment of patients with known or suspected coronary artery disease and is well established for diagnosis and for prognostic evaluation in these patients. The dedicated cardiac SPECT cameras with solid-state cadmium zinc telluride (CZT) detectors were first introduced a decade ago. A large body of evidence is building up, showing the superiority of the new technology compared with conventional gamma cameras. Not only the CZT detectors, but also new collimator geometries, the ability to perform focused imaging optimized for the heart and advances in data processing algorithms all contribute to the significantly improved sensitivity up to 8-10 times, as well as improved energy resolution and improved reconstructed spatial resolution compared with conventional technology. In this article, we provide an overview of the physical characteristics of the CZT cameras, as well as a review of the literature published so far, including validation studies in comparison with conventional myocardial perfusion imaging and with invasive coronary angiography, significant reduction in radiation dose, and new imaging protocols enabled by the new technology. PMID:27237438

  16. EANM procedural guidelines for radionuclide myocardial perfusion imaging with SPECT and SPECT/CT: 2015 revision.

    PubMed

    Verberne, Hein J; Acampa, Wanda; Anagnostopoulos, Constantinos; Ballinger, Jim; Bengel, Frank; De Bondt, Pieter; Buechel, Ronny R; Cuocolo, Alberto; van Eck-Smit, Berthe L F; Flotats, Albert; Hacker, Marcus; Hindorf, Cecilia; Kaufmann, Philip A; Lindner, Oliver; Ljungberg, Michael; Lonsdale, Markus; Manrique, Alain; Minarik, David; Scholte, Arthur J H A; Slart, Riemer H J A; Trägårdh, Elin; de Wit, Tim C; Hesse, Birger

    2015-11-01

    Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated 2015 procedural guidelines are highlighted, focusing on the important changes related to new instrumentation with improved image information and the possibility to reduce radiation exposure, which is further discussed in relation to the recent developments of new International Commission on Radiological Protection (ICRP) models. Introduction of the selective coronary vasodilator regadenoson and the use of coronary CT-contrast agents for hybrid imaging with SPECT/CT angiography are other important areas for nuclear cardiology that were not included in the previous guidelines. A large number of minor changes have been described in more detail in the fully revised version available at the EANM home page: http://eanm.org/publications/guidelines/2015_07_EANM_FINAL_myocardial_perfusion_guideline.pdf . PMID:26290421

  17. 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.

  18. What is the benefit of CT-based attenuation correction in myocardial perfusion SPET?

    PubMed

    Apostolopoulos, Dimitrios J; Savvopoulos, Christos

    2016-01-01

    In multimodality imaging, CT-derived transmission maps are used for attenuation correction (AC) of SPET or PET data. Regarding SPET myocardial perfusion imaging (MPI), however, the bene����t of CT-based AC (CT-AC) has been questioned. Although most attenuation-related artifacts are removed by this technique, new false defects may appear while some true perfusion abnormalities may be masked. The merits and the drawbacks of CT-AC in MPI SPET are reviewed and discussed in this editorial. In conclusion, CT-AC is most helpful in men, overweight in particular, and in those with low or low to intermediate pre-test probability of coronary artery disease (CAD). It is also useful for the evaluation of myocardial viability. In high-risk patients though, CT-AC may underestimate the presence or the extent of CAD. In any case, corrected and non-corrected images should be viewed side-by-side and both considered in the interpretation of the study. PMID:27331200

  19. Quantitative myocardial perfusion PET parametric imaging at the voxel-level.

    PubMed

    Mohy-Ud-Din, Hassan; Lodge, Martin A; Rahmim, Arman

    2015-08-01

    Quantitative myocardial perfusion (MP) PET has the potential to enhance detection of early stages of atherosclerosis or microvascular dysfunction, characterization of flow-limiting effects of coronary artery disease (CAD), and identification of balanced reduction of flow due to multivessel stenosis. We aim to enable quantitative MP-PET at the individual voxel level, which has the potential to allow enhanced visualization and quantification of myocardial blood flow (MBF) and flow reserve (MFR) as computed from uptake parametric images. This framework is especially challenging for the (82)Rb radiotracer. The short half-life enables fast serial imaging and high patient throughput; yet, the acquired dynamic PET images suffer from high noise-levels introducing large variability in uptake parametric images and, therefore, in the estimates of MBF and MFR. Robust estimation requires substantial post-smoothing of noisy data, degrading valuable functional information of physiological and pathological importance. We present a feasible and robust approach to generate parametric images at the voxel-level that substantially reduces noise without significant loss of spatial resolution. The proposed methodology, denoted physiological clustering, makes use of the functional similarity of voxels to penalize deviation of voxel kinetics from physiological partners. The results were validated using extensive simulations (with transmural and non-transmural perfusion defects) and clinical studies. Compared to post-smoothing, physiological clustering depicted enhanced quantitative noise versus bias performance as well as superior recovery of perfusion defects (as quantified by CNR) with minimal increase in bias. Overall, parametric images obtained from the proposed methodology were robust in the presence of high-noise levels as manifested in the voxel time-activity-curves. PMID:26216052

  20. Quantitative myocardial perfusion PET parametric imaging at the voxel-level

    NASA Astrophysics Data System (ADS)

    Mohy-ud-Din, Hassan; Lodge, Martin A.; Rahmim, Arman

    2015-08-01

    Quantitative myocardial perfusion (MP) PET has the potential to enhance detection of early stages of atherosclerosis or microvascular dysfunction, characterization of flow-limiting effects of coronary artery disease (CAD), and identification of balanced reduction of flow due to multivessel stenosis. We aim to enable quantitative MP-PET at the individual voxel level, which has the potential to allow enhanced visualization and quantification of myocardial blood flow (MBF) and flow reserve (MFR) as computed from uptake parametric images. This framework is especially challenging for the 82Rb radiotracer. The short half-life enables fast serial imaging and high patient throughput; yet, the acquired dynamic PET images suffer from high noise-levels introducing large variability in uptake parametric images and, therefore, in the estimates of MBF and MFR. Robust estimation requires substantial post-smoothing of noisy data, degrading valuable functional information of physiological and pathological importance. We present a feasible and robust approach to generate parametric images at the voxel-level that substantially reduces noise without significant loss of spatial resolution. The proposed methodology, denoted physiological clustering, makes use of the functional similarity of voxels to penalize deviation of voxel kinetics from physiological partners. The results were validated using extensive simulations (with transmural and non-transmural perfusion defects) and clinical studies. Compared to post-smoothing, physiological clustering depicted enhanced quantitative noise versus bias performance as well as superior recovery of perfusion defects (as quantified by CNR) with minimal increase in bias. Overall, parametric images obtained from the proposed methodology were robust in the presence of high-noise levels as manifested in the voxel time-activity-curves.

  1. Cardiac function and myocardial perfusion immediately following maximal treadmill exercise inside the MRI room

    PubMed Central

    Jekic, Mihaela; Foster, Eric L; Ballinger, Michelle R; Raman, Subha V; Simonetti, Orlando P

    2008-01-01

    Treadmill exercise stress testing is an essential tool in the prevention, detection, and treatment of a broad spectrum of cardiovascular disease. After maximal exercise, cardiac images at peak stress are typically acquired using nuclear scintigraphy or echocardiography, both of which have inherent limitations. Although CMR offers superior image quality, the lack of MRI-compatible exercise and monitoring equipment has prevented the realization of treadmill exercise CMR. It is critical to commence imaging as quickly as possible after exercise to capture exercise-induced cardiac wall motion abnormalities. We modified a commercial treadmill such that it could be safely positioned inside the MRI room to minimize the distance between the treadmill and the scan table. We optimized the treadmill exercise CMR protocol in 20 healthy volunteers and successfully imaged cardiac function and myocardial perfusion at peak stress, followed by viability imaging at rest. Imaging commenced an average of 30 seconds after maximal exercise. Real-time cine of seven slices with no breath-hold and no ECG-gating was completed within 45 seconds of exercise, immediately followed by stress perfusion imaging of three short-axis slices which showed an average time to peak enhancement within 57 seconds of exercise. We observed a 3.1-fold increase in cardiac output and a myocardial perfusion reserve index of 1.9, which agree with reported values for healthy subjects at peak stress. This study successfully demonstrates in-room treadmill exercise CMR in healthy volunteers, but confirmation of feasibility in patients with heart disease is still needed. PMID:18272005

  2. Dynamic CT myocardial perfusion imaging: detection of ischemia in a porcine model with FFR verification

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2014-03-01

    Dynamic cardiac CT perfusion (CTP) is a high resolution, non-invasive technique for assessing myocardial blood ow (MBF), which in concert with coronary CT angiography enable CT to provide a unique, comprehensive, fast analysis of both coronary anatomy and functional ow. We assessed perfusion in a porcine model with and without coronary occlusion. To induce occlusion, each animal underwent left anterior descending (LAD) stent implantation and angioplasty balloon insertion. Normal ow condition was obtained with balloon completely de ated. Partial occlusion was induced by balloon in ation against the stent with FFR used to assess the extent of occlusion. Prospective ECG-triggered partial scan images were acquired at end systole (45% R-R) using a multi-detector CT (MDCT) scanner. Images were reconstructed using FBP and a hybrid iterative reconstruction (iDose4, Philips Healthcare). Processing included: beam hardening (BH) correction, registration of image volumes using 3D cubic B-spline normalized mutual-information, and spatio-temporal bilateral ltering to reduce partial scan artifacts and noise variation. Absolute blood ow was calculated with a deconvolutionbased approach using singular value decomposition (SVD). Arterial input function was estimated from the left ventricle (LV) cavity. Regions of interest (ROIs) were identi ed in healthy and ischemic myocardium and compared in normal and occluded conditions. Under-perfusion was detected in the correct LAD territory and ow reduction agreed well with FFR measurements. Flow was reduced, on average, in LAD territories by 54%.

  3. Prevalence and Severity of Myocardial Perfusion Imaging Abnormalities in Inmate Subjects

    PubMed Central

    Acampa, Wanda; Nappi, Carmela; Gaudieri, Valeria; Frega, Nicola; D’Arienzo, Davide; Tuccillo, Marianna; Di Lorenzo, Pierpaolo; Buccelli, Claudio; Petretta, Mario; Cuocolo, Alberto

    2015-01-01

    Aim We evaluated the prevalence and severity of myocardial perfusion abnormalities among inmates undergoing cardiac single-photon emission computed tomography. We also compared the results with those obtained in a cohort of non-inmates. Methods Between January 2009 and December 2013, 2420 consecutive subjects (258 inmates and 2162 non-inmates) with suspected or known coronary artery disease underwent stress myocardial perfusion single-photon emission computed tomography (MPS) to our institution. The decision to submit inmates to MPS was taken by the physicians of the penal institutions or ordered by the court based on the survey of part. To account for differences in clinical characteristics between inmates and non-inmates, we created a propensity score-matched cohort considering clinical variables and stress type. Results Before matching, inmates were younger and had higher prevalence of male gender, smoking, chest pain, and previous myocardial infarction or revascularization (all p < 0.001). After matching, all characteristics were comparable in 258 inmates and 258 non-inmates. The total amount of abnormal myocardium was similar in inmates and non-inmates before and after matching. Infarct size and severity were larger in inmates before (p < 0.001) and after (p < 0.01) matching and left ventricular ejection fraction was lower in inmates compared to non-inmates (p < 0.01). Conclusions Detention is associated with larger infarct size compared to a general population of subjects referred to stress MPS also after matching for clinical variables and stress type. The similar prevalence of normal MPS in the matched cohort suggests that this imaging technique might be appropriate in inmates. PMID:26200782

  4. Comparison Between Postprocessing Software and Repeated Scanning to Eliminate Subdiaphragmatic Activity in Myocardial Perfusion Scintigraphy.

    PubMed

    Theerakulpisut, Daris; Chotipanich, Chanisa

    2016-01-01

    Myocardial perfusion single photon emission computed tomography (SPECT) is a powerful test of evaluation for coronary artery disease, but subdiaphragmatic radiotracer activity often interferes with the interpretation of inferior wall findings. This study aims to evaluate the effectiveness of using software elimination of the subdiaphragmatic activity for the assessment of its efficacy in the correctness of image interpretation and the overall image quality of myocardial perfusion scintigraphy (MPS). MPS studies from January 2010 to October 2012 at our institution were reviewed. Thirty-two SPECT studies were included, all of which had significant subdiaphragmatic activity in the first scan and needed to be delayed to let the activity clear. Each scan was interpreted by using semiquantitative scoring in 17 segments according to the degree of radiotracer uptake. The first scan, which had interfering activity, was manipulated by masking out the unwanted activity with software native to our image processing software suite. The manipulated images were then compared with delayed images of the same patient, of which the subdiaphragmatic activity was spontaneously cleared with time. The first scan masked by software correlated with the delayed scan for myocardial regions supplied by the left circumflex (LCx) and right coronary artery (RCA), but not the left anterior descending (LAD). However, the quality of the masked scans was perceived by the observer to be better in terms of quality and ease of interpretation. Using software to mask out unwanted subdiaphragmatic activity has no detrimental effect on the interpretation of MPS images when compared with delayed scanning, but it can improve subjective scan quality and ease of interpretation. PMID:27134559

  5. Localization of coronary artery disease with exercise electrocardiography: correlation with thallium-201 myocardial perfusion scanning

    SciTech Connect

    Dunn, R.F.; Freedman, B.; Bailey, I.K.; Uren, R.F.; Kelly, D.T.

    1981-11-01

    In 61 patients with single vessel coronary artery disease (70 percent or greater obstruction of luminal diameter in only one vessel) and no previous myocardial infarction, the sites of ischemic changes on 12 lead exercise electrocardiography and on thallium-201 myocardial perfusion scanning were related to the obstructed coronary artery. The site of exercise-induced S-T segment depression did not identify which coronary artery was obstructed. In the 37 patients with left anterior descending coronary artery disease S-T depression was most often seen in the inferior leads and leads V4 to V6, and in the 18 patients with right coronary artery disease and in the 6 patients with left circumflex artery disease S-T depression was most often seen in leads V5 and V6. Although S-T segment elevation was uncommon in most leads, it occurred in lead V1 or a VL, or both, in 51 percent of the patients with left anterior descending coronary artery disease. A reversible anterior defect on exercise thallium scanning correlated with left anterior descending coronary artery disease (probability (p) less than 0.0001) and a reversible inferior thallium defect correlated with right coronary or left circumflex artery disease (p less than 0.0001). In patients with single vessel disease, the site of S-T segment depression does not identify the obstructed coronary artery; S-T segment elevation in lead V1 or aVL, or both, identifies left anterior descending coronary artery disease; and the site of reversible perfusion defect on thallium scanning identifies the site of myocardial ischemia and the obstructed coronary artery.

  6. Comparison Between Postprocessing Software and Repeated Scanning to Eliminate Subdiaphragmatic Activity in Myocardial Perfusion Scintigraphy

    PubMed Central

    Theerakulpisut, Daris; Chotipanich, Chanisa

    2016-01-01

    Myocardial perfusion single photon emission computed tomography (SPECT) is a powerful test of evaluation for coronary artery disease, but subdiaphragmatic radiotracer activity often interferes with the interpretation of inferior wall findings. This study aims to evaluate the effectiveness of using software elimination of the subdiaphragmatic activity for the assessment of its efficacy in the correctness of image interpretation and the overall image quality of myocardial perfusion scintigraphy (MPS). MPS studies from January 2010 to October 2012 at our institution were reviewed. Thirty-two SPECT studies were included, all of which had significant subdiaphragmatic activity in the first scan and needed to be delayed to let the activity clear. Each scan was interpreted by using semiquantitative scoring in 17 segments according to the degree of radiotracer uptake. The first scan, which had interfering activity, was manipulated by masking out the unwanted activity with software native to our image processing software suite. The manipulated images were then compared with delayed images of the same patient, of which the subdiaphragmatic activity was spontaneously cleared with time. The first scan masked by software correlated with the delayed scan for myocardial regions supplied by the left circumflex (LCx) and right coronary artery (RCA), but not the left anterior descending (LAD). However, the quality of the masked scans was perceived by the observer to be better in terms of quality and ease of interpretation. Using software to mask out unwanted subdiaphragmatic activity has no detrimental effect on the interpretation of MPS images when compared with delayed scanning, but it can improve subjective scan quality and ease of interpretation. PMID:27134559

  7. Myocardial uptake of thallium and rubidium during alterations in perfusion and oxygenation in isolated rabbit hearts

    SciTech Connect

    Leppo, J.A.

    1987-05-01

    The comparative effects of altered cellular function and coronary perfusion on myocardial /sup 201/Tl and /sup 83/Rb uptake were evaluated in three groups of isolated rabbit hearts having isovolumic contractions. Paired-indication dilution experiments were performed with /sup 201/Tl, /sup 83/Rb, and /sup 111/In-labeled albumin as an intravascular reference marker. In Group A hearts (n = 12), isotope transport was determined during control, hypoxia, and ischemia. In Group B hearts (n = 8), isotope transport was measured at control flow and again at a 50% and 80% reduction. In Group C hearts (n = 8) only /sup 201/Tl uptake was determined at control and following coronary reperfusion. Myocardial /sup 201/Tl and /sup 83/Rb transport were not significantly different and were proportional to flow. Although all interventions caused significant hemodynamic alterations, neither tracer was affected by hypoxia at constant flow. Thallium-201 permeation, however, was transiently decreased immediately after coronary reperfusion. We conclude that myocardial uptake of /sup 201/Tl and /sup 83/Rb are similar and directly related to flow, but do not reflect hypoxia induced cellular dysfunction.

  8. Automatic detection of the myocardial boundaries of the right and left ventricles in MR cardio perfusion scans

    NASA Astrophysics Data System (ADS)

    Spreeuwers, Luuk J.; Breeuwer, Marcel M.

    2001-07-01

    Recent advances in Magnetic Resonance Imaging allow fast recording of contrast enhanced myocardial perfusion scans. MR perfusion scans are made by recording, during a period of 20-40 seconds a number of short-axis slices through the myocardium. The scanning is triggered by the patient's ECG typically resulting in one set of slices per heart beat. For the perfusion analysis, the myocardial boundaries must be traced in all images Currently this is done manually, a tedious procedure, prone to inter- and intra-observer variability. In this paper a method for automatic detection of myocardial boundaries is proposed. This results in a considerable time reduction of the analysis and is an important step towards automatic analysis of cardiac MR perfusion scans. The most important consideration in the proposed approach is the use of not only spatial-intensity information, but also intensity-time and shape information to realize a robust segmentation. The procedure was tested on a total of 30 image sequences from 14 different scans. From 26 out of 30 sequences the myocardial boundaries were correctly found. The remaining 4 sequences were of very low quality and would most likely not be used for analysis.

  9. Quantitative Myocardial Perfusion with Dynamic Contrast-Enhanced Imaging in MRI and CT: Theoretical Models and Current Implementation

    PubMed Central

    Handayani, A.; Dijkstra, H.; Prakken, N. H. J.; Slart, R. H. J. A.; Oudkerk, M.; Van Ooijen, P. M. A.; Vliegenthart, R.; Sijens, P. E.

    2016-01-01

    Technological advances in magnetic resonance imaging (MRI) and computed tomography (CT), including higher spatial and temporal resolution, have made the prospect of performing absolute myocardial perfusion quantification possible, previously only achievable with positron emission tomography (PET). This could facilitate integration of myocardial perfusion biomarkers into the current workup for coronary artery disease (CAD), as MRI and CT systems are more widely available than PET scanners. Cardiac PET scanning remains expensive and is restricted by the requirement of a nearby cyclotron. Clinical evidence is needed to demonstrate that MRI and CT have similar accuracy for myocardial perfusion quantification as PET. However, lack of standardization of acquisition protocols and tracer kinetic model selection complicates comparison between different studies and modalities. The aim of this overview is to provide insight into the different tracer kinetic models for quantitative myocardial perfusion analysis and to address typical implementation issues in MRI and CT. We compare different models based on their theoretical derivations and present the respective consequences for MRI and CT acquisition parameters, highlighting the interplay between tracer kinetic modeling and acquisition settings. PMID:27088083

  10. Quantitative Myocardial Perfusion with Dynamic Contrast-Enhanced Imaging in MRI and CT: Theoretical Models and Current Implementation.

    PubMed

    Pelgrim, G J; Handayani, A; Dijkstra, H; Prakken, N H J; Slart, R H J A; Oudkerk, M; Van Ooijen, P M A; Vliegenthart, R; Sijens, P E

    2016-01-01

    Technological advances in magnetic resonance imaging (MRI) and computed tomography (CT), including higher spatial and temporal resolution, have made the prospect of performing absolute myocardial perfusion quantification possible, previously only achievable with positron emission tomography (PET). This could facilitate integration of myocardial perfusion biomarkers into the current workup for coronary artery disease (CAD), as MRI and CT systems are more widely available than PET scanners. Cardiac PET scanning remains expensive and is restricted by the requirement of a nearby cyclotron. Clinical evidence is needed to demonstrate that MRI and CT have similar accuracy for myocardial perfusion quantification as PET. However, lack of standardization of acquisition protocols and tracer kinetic model selection complicates comparison between different studies and modalities. The aim of this overview is to provide insight into the different tracer kinetic models for quantitative myocardial perfusion analysis and to address typical implementation issues in MRI and CT. We compare different models based on their theoretical derivations and present the respective consequences for MRI and CT acquisition parameters, highlighting the interplay between tracer kinetic modeling and acquisition settings. PMID:27088083

  11. Quantitative myocardial perfusion imaging in a porcine ischemia model using a prototype spectral detector CT system.

    PubMed

    Fahmi, Rachid; Eck, Brendan L; Levi, Jacob; Fares, Anas; Dhanantwari, Amar; Vembar, Mani; Bezerra, Hiram G; Wilson, David L

    2016-03-21

    We optimized and evaluated dynamic myocardial CT perfusion (CTP) imaging on a prototype spectral detector CT (SDCT) scanner. Simultaneous acquisition of energy sensitive projections on the SDCT system enabled projection-based material decomposition, which typically performs better than image-based decomposition required by some other system designs. In addition to virtual monoenergetic, or keV images, the SDCT provided conventional (kVp) images, allowing us to compare and contrast results. Physical phantom measurements demonstrated linearity of keV images, a requirement for quantitative perfusion. Comparisons of kVp to keV images demonstrated very significant reductions in tell-tale beam hardening (BH) artifacts in both phantom and pig images. In phantom images, consideration of iodine contrast to noise ratio and small residual BH artifacts suggested optimum processing at 70 keV. The processing pipeline for dynamic CTP measurements included 4D image registration, spatio-temporal noise filtering, and model-independent singular value decomposition deconvolution, automatically regularized using the L-curve criterion. In normal pig CTP, 70 keV perfusion estimates were homogeneous throughout the myocardium. At 120 kVp, flow was reduced by more than 20% on the BH-hypo-enhanced myocardium, a range that might falsely indicate actionable ischemia, considering the 0.8 threshold for actionable FFR. With partial occlusion of the left anterior descending (LAD) artery (FFR  <  0.8), perfusion defects at 70 keV were correctly identified in the LAD territory. At 120 kVp, BH affected the size and flow in the ischemic area; e.g. with FFR [Formula: see text] 0.65, the anterior-to-lateral flow ratio was 0.29  ±  0.01, over-estimating stenosis severity as compared to 0.42  ±  0.01 (p  <  0.05) at 70 keV. On the non-ischemic inferior wall (not a LAD territory), the flow ratio was 0.50  ±  0.04 falsely indicating an actionable ischemic condition

  12. Quantitative myocardial perfusion imaging in a porcine ischemia model using a prototype spectral detector CT system

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Dhanantwari, Amar; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    We optimized and evaluated dynamic myocardial CT perfusion (CTP) imaging on a prototype spectral detector CT (SDCT) scanner. Simultaneous acquisition of energy sensitive projections on the SDCT system enabled projection-based material decomposition, which typically performs better than image-based decomposition required by some other system designs. In addition to virtual monoenergetic, or keV images, the SDCT provided conventional (kVp) images, allowing us to compare and contrast results. Physical phantom measurements demonstrated linearity of keV images, a requirement for quantitative perfusion. Comparisons of kVp to keV images demonstrated very significant reductions in tell-tale beam hardening (BH) artifacts in both phantom and pig images. In phantom images, consideration of iodine contrast to noise ratio and small residual BH artifacts suggested optimum processing at 70 keV. The processing pipeline for dynamic CTP measurements included 4D image registration, spatio-temporal noise filtering, and model-independent singular value decomposition deconvolution, automatically regularized using the L-curve criterion. In normal pig CTP, 70 keV perfusion estimates were homogeneous throughout the myocardium. At 120 kVp, flow was reduced by more than 20% on the BH-hypo-enhanced myocardium, a range that might falsely indicate actionable ischemia, considering the 0.8 threshold for actionable FFR. With partial occlusion of the left anterior descending (LAD) artery (FFR  <  0.8), perfusion defects at 70 keV were correctly identified in the LAD territory. At 120 kVp, BH affected the size and flow in the ischemic area; e.g. with FFR ≈ 0.65, the anterior-to-lateral flow ratio was 0.29  ±  0.01, over-estimating stenosis severity as compared to 0.42  ±  0.01 (p  <  0.05) at 70 keV. On the non-ischemic inferior wall (not a LAD territory), the flow ratio was 0.50  ±  0.04 falsely indicating an actionable ischemic condition in a healthy

  13. Quantification of myocardial perfusion using CMR with a radial data acquisition: comparison with a dual-bolus method

    PubMed Central

    2010-01-01

    Background Quantitative estimates of myocardial perfusion generally require accurate measurement of the arterial input function (AIF). The saturation of signal intensity in the blood that occurs with most doses of contrast agent makes obtaining an accurate AIF challenging. This work seeks to evaluate the performance of a method that uses a radial k-space perfusion sequence and multiple saturation recovery times (SRT) to quantify myocardial perfusion with cardiovascular magnetic resonance (CMR). Methods Perfusion CMR was performed at 3 Tesla with a saturation recovery radial turboFLASH sequence with 72 rays. Fourteen subjects were given a low dose (0.004 mmol/kg) of dilute (1/5 concentration) contrast agent (Gd-BOPTA) and then a higher non-dilute dose of the same volume (0.02 mmol/kg). AIFs were calculated from the blood signal in three sub-images with differing effective saturation recovery times. The full and sub-images were reconstructed iteratively with a total variation constraint. The images from the full 72 ray data were processed to obtain six tissue enhancement curves in two slices of the left ventricle in each subject. A 2-compartment model was used to determine absolute flows Results The proposed multi-SRT method resulted in AIFs that were similar to those obtained with the dual-bolus method. Myocardial blood flow (MBF) estimates from the dual-bolus and the multi-SRT methods were related by MBFmulti-SRT = 0.85MBFdual-bolus + 0.18 (r = 0.91). Conclusions The multi-SRT method, which uses a radial k-space perfusion sequence, can be used to obtain an accurate AIF and thus quantify myocardial perfusion for doses of contrast agent that result in a relatively saturated AIF. PMID:20653961

  14. Assessment of cardiac function using myocardial perfusion imaging technique on SPECT with 99mTc sestamibi

    NASA Astrophysics Data System (ADS)

    Gani, M. R. A.; Nazir, F.; Pawiro, S. A.; Soejoko, D. S.

    2016-03-01

    Suspicion on coronary heart disease can be confirmed by observing the function of left ventricle cardiac muscle with Myocardial Perfusion Imaging techniques. The function perfusion itself is indicated by the uptake of radiopharmaceutical tracer. The 31 patients were studied undergoing the MPI examination on Gatot Soebroto Hospital using 99mTc-sestamibi radiopharmaceutical with stress and rest conditions. Stress was stimulated by physical exercise or pharmacological agent. After two hours, the patient did rest condition on the same day. The difference of uptake percentage between stress and rest conditions will be used to determine the malfunction of perfusion due to ischemic or infarct. Degradation of cardiac function was determined based on the image-based assessment of five segments of left ventricle cardiac. As a result, 8 (25.8%) patients had normal myocardial perfusion and 11 (35.5%) patients suspected for having partial ischemia. Total ischemia occurred to 8 (25.8%) patients with reversible and irreversible ischemia and the remaining 4 (12.9%) patients for partial infarct with characteristic the percentage of perfusion ≤50%. It is concluded that MPI technique of image-based assessment on uptake percentage difference between stress and rest conditions can be employed to predict abnormal perfusion as complementary information to diagnose the cardiac function.

  15. Simultaneous myocardial strain and dark-blood perfusion imaging using a displacement-encoded MRI pulse sequence.

    PubMed

    Le, Yuan; Stein, Ashley; Berry, Colin; Kellman, Peter; Bennett, Eric E; Taylor, Joni; Lucas, Katherine; Kopace, Rael; Chefd'Hotel, Christophe; Lorenz, Christine H; Croisille, Pierre; Wen, Han

    2010-09-01

    The purpose of this study is to develop and evaluate a displacement-encoded pulse sequence for simultaneous perfusion and strain imaging. Displacement-encoded images in two to three myocardial slices were repeatedly acquired using a single-shot pulse sequence for 3 to 4 min, which covers a bolus infusion of Gadolinium contrast. The magnitudes of the images were T(1) weighted and provided quantitative measures of perfusion, while the phase maps yielded strain measurements. In an acute coronary occlusion swine protocol (n = 9), segmental perfusion measurements were validated against microsphere reference standard with a linear regression (slope 0.986, R(2) = 0.765, Bland-Altman standard deviation = 0.15 mL/min/g). In a group of ST-elevation myocardial infarction patients (n = 11), the scan success rate was 76%. Short-term contrast washout rate and perfusion are highly correlated (R(2) = 0.72), and the pixelwise relationship between circumferential strain and perfusion was better described with a sigmoidal Hill curve than linear functions. This study demonstrates the feasibility of measuring strain and perfusion from a single set of images. PMID:20544714

  16. Incidentally detected diaphragmatic hernia mimicking angina pectoris with Tc-99m MIBI myocardial perfusion imaging

    PubMed Central

    Cınar, Alev; Sadıc, Murat; Demırel, Koray; Korkmaz, Meliha

    2013-01-01

    In recent years 99mTechnetium methoxy-isobutyl-isonitrile (99mTc MIBI) is widely used in the evaluation of myocardial perfusion imaging (MPI). In this imaging protocol besides the cardiac evaluation, numerous other organs are included in the field of view. 99mTechnetium MIBI is taken up in all metabolically active tissue in the body except for the brain. Extracardiac uptake patterns as benign or serious conditions can be revealed during the MPI. In the imaging protocol, we should be aware of distribution of this radiotracer in order to recognize the abnormal uptake. Here in, we present a large diaphragmatic hernia, seemed as a mirror vision of myocardium that was determined incidentally during the MPI with 99mTc MIBI. PMID:24379540

  17. Observer performance with computer-generated images of /sup 201/Tl-Cl myocardial perfusion

    SciTech Connect

    Wiener, S.N.; Flynn, M.J.; Edelstein, J.

    1980-07-01

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

  18. Adenosine decreases post-ischaemic cardiac TNF-alpha production: anti-inflammatory implications for preconditioning and transplantation.

    PubMed Central

    Meldrum, D R; Cain, B S; Cleveland, J C; Meng, X; Ayala, A; Banerjee, A; Harken, A H

    1997-01-01

    Tumour necrosis factor-alpha (TNF-alpha) is an autocrine contributor to myocardial dysfunction and cardiomyocyte death in ischaemia-reperfusion injury (I/R), sepsis, chronic heart failure and cardiac allograft rejection. Cardiac resident macrophages, infiltrating leucocytes, and cardiomyocytes themselves produce TNF-alpha. Although adenosine reduces macrophage TNF-alpha production and protects myocardium against I/R, it remains unknown whether I/R induces an increase in cardiac TNF-alpha in a crystalloid-perfused model (in the absence of blood), and, whether adenosine decreases cardiac TNF-alpha and protects function after I/R. To study this, isolated rat hearts were crystalloid-perfused using the Langendorff method and subjected to I/R, with or without adenosine pretreatment. Post-ischaemic cardiac TNF-alpha (enzyme-linked immunosorbent assay and bioassay) and function were determined (Langendorff). I/R increased cardiac TNF-alpha and impaired myocardial function. Adenosine decreased cardiac TNF-alpha and improved post-ischaemic functional recovery. This study demonstrates that: first, I/R induces an increase in cardiac tissue TNF-alpha in a crystalloid-perfused model: second, adenosine decreases cardiac TNF-alpha and improves post-ischaemic myocardial function; third, decreased cardiac TNF-alpha may represent a mechanism by which adenosine protects myocardium; and fourth, adenosine-induced suppression of cardiac TNF-alpha may provide an anti-inflammatory link to preconditioning and have implications for cardiac allograft preservation. PMID:9497488

  19. Biodistribution and Stability Studies of [18F]Fluoroethylrhodamine B, a Potential PET Myocardial Perfusion Agent

    PubMed Central

    Gottumukkala, Vijay; Heinrich, Tobias K.; Baker, Amanda; Dunning, Patricia; Fahey, Frederick H; Treves, S. Ted; Packard, Alan B.

    2010-01-01

    Introduction Fluorine-18-labeled rhodamine B was developed as a potential PET tracer for the evaluation of myocardial perfusion, but preliminary studies in mice showed no accumulation in the heart suggesting that it was rapidly hydrolyzed in vivo in mice. A study was, therefore, undertaken to further evaluate this hypothesis. Methods [18F]Fluoroethylrhodamine B was equilibrated for 2 h at 37 °C in human, rat and mouse serum and in PBS. Samples were removed periodically and assayed by HPLC. Based on the results of the stability study, microPET imaging and a biodistribution study were carried out in rats. Results In vitro stability studies demonstrated that [18F]fluoroethylrhodamine B much more stable in rat and human sera than in mouse serum. After 2 h, the compound was >80% intact in rat serum but <30% intact in mouse serum. The microPET imaging and biodistribution studies in rats confirmed this result showing high and persistent tracer accumulation in the myocardium compared with the absence of uptake by the myocardium in mice thereby validating our original hypothesis that 18F-labeled rhodamines should accumulate in the heart. Conclusions [18F]Fluoroethyl rhodamine B is more stable in rat and human sera than it is in mouse serum. This improved stability is demonstrated by the high uptake of the tracer in the rat heart in comparison to the absence of visible uptake in the mouse heart. These observations suggest that 18F-labeled rhodamines are promising candidates for more extensive evaluation as PET tracers for the evaluation of myocardial perfusion. PMID:20346876

  20. Optimization of a protocol for myocardial perfusion scintigraphy by using an anthropomorphic phantom*

    PubMed Central

    Ramos, Susie Medeiros Oliveira; Glavam, Adriana Pereira; Kubo, Tadeu Takao Almodovar; de Sá, Lidia Vasconcellos

    2014-01-01

    Objective To develop a study aiming at optimizing myocardial perfusion imaging. Materials and Methods Imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The 99mTc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. Results The results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. Conclusion The described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol. PMID:25741088

  1. Accelerating free breathing myocardial perfusion MRI using multi coil radial k - t SLR

    NASA Astrophysics Data System (ADS)

    Goud Lingala, Sajan; DiBella, Edward; Adluru, Ganesh; McGann, Christopher; Jacob, Mathews

    2013-10-01

    The clinical utility of myocardial perfusion MR imaging (MPI) is often restricted by the inability of current acquisition schemes to simultaneously achieve high spatio-temporal resolution, good volume coverage, and high signal to noise ratio. Moreover, many subjects often find it difficult to hold their breath for sufficiently long durations making it difficult to obtain reliable MPI data. Accelerated acquisition of free breathing MPI data can overcome some of these challenges. Recently, an algorithm termed as k - t SLR has been proposed to accelerate dynamic MRI by exploiting sparsity and low rank properties of dynamic MRI data. The main focus of this paper is to further improve k - t SLR and demonstrate its utility in considerably accelerating free breathing MPI. We extend its previous implementation to account for multi-coil radial MPI acquisitions. We perform k - t sampling experiments to compare different radial trajectories and determine the best sampling pattern. We also introduce a novel augmented Lagrangian framework to considerably improve the algorithm’s convergence rate. The proposed algorithm is validated using free breathing rest and stress radial perfusion data sets from two normal subjects and one patient with ischemia. k - t SLR was observed to provide faithful reconstructions at high acceleration levels with minimal artifacts compared to existing MPI acceleration schemes such as spatio-temporal constrained reconstruction and k - t SPARSE/SENSE.

  2. Influence of revascularization on myocardial perfusion, metabolism and function evaluated with I-123-IPPA

    SciTech Connect

    Kropp, J.; Krois, M.; Eichhorn, B.; Feske, W.; Likungu, J.; Kirchhoff, P.J.; Luederitz, B.; Biersack, H.J.; Knapp, F.F. Jr.

    1993-10-01

    Patients with coronary artery disease (CAD) were investigated with sequential SPECT-scintigraphy after administration of 200 MBq of 15-(p-[I-123]iodophenyl)pentadecanoic acid (IPPA) at peak submaximal exercise. Twenty patients underwent coronary angioplasty (PTCA) from which 14 had control coronary arteriography (CA) and left ventricular cineventriculography (LVCV). Nineteen pts underwent bypass graft surgery (ACB) and stress sonagraphy. Semi-quantification of uptake (Up related to perfusion) and turnover (Tr) was obtained by segmental comparison of oblique slices. About 90% of the reperfused myocardial segments in the PTCA-group and 76% in the ACB-group showed an improvement of uptake after therapy (RUp). Of these, 50% and 66% exhibited increased turnover (RTr) after PTCA or ACB. Pathologic RTr was highly correlated with regional wall motion abnormalities after therapy in both groups. In the ACB-group presence of improvement of RTr was correlated with improved RWM at rest and stress. IPPA-studies show potential to provide information about changes of perfusion and metabolism after reperfusion and IPPA-turnover is a good predictor of the pattern of contractile function.

  3. Renal uptake of Tl-201 in hypertensive patients undergoing myocardial perfusion imaging

    SciTech Connect

    Hurwitz, G.A.; Mattar, A.G.; Bhargava, R.; Driedger, A.A.; Hogendoorn, P.; Wesolowski, C.A. )

    1990-02-01

    The detection of renovascular disease (RVD) has particular relevance in hypertensive patients (HP) who have symptoms of target organ damage. To evaluate the possibility of RVD in HP undergoing myocardial perfusion scintigraphy for chest pain symptoms, posterior renal images were obtained at 1-3 hours after Tl-201 injection. Analog and computer images were obtained for 5 minutes in 45 HP; 12 patients with no history of hypertension or renal disease served as normal controls. For qualitative analysis, images were coded and read by three observers as to symmetry of renal uptake. Differential renal uptake of Tl-201 (DRU) was quantitated on computer images. In normal controls, uptake was agreed on as symmetric. In HP, 6 patients had marked asymmetry of DRU and 4 had possibly significant asymmetry; 2 had decreased uptake in both kidneys suggesting bilateral RVD or nephrosclerosis. Objective correlation with DRU was obtained in 10 HP who had contrast angiography, confirming 4 cases of unilateral RVD and 2 of bilateral RVD. Thirteen patients also had renography with Tc-99m DTPA; differential renal function by this modality correlated well with DRU of Tl-201 (r = 0.98). Thus, DRU of Tl-201 can be used as a supplement to myocardial scintigraphy to identify HP who require further evaluation and treatment of RVD.

  4. Inflammatory Markers and Intimal Media Thickness in Diabetics with Negative Myocardial Perfusion Scan

    PubMed Central

    Shakir, Douraid K.; Mohmmed, Ibrahim; Zarie, Mahmood; Kateeb, Dawod Al; Kiliyanni, Abdul Salim; Suwaidi, Jassim Al

    2009-01-01

    Background We compared the type and duration of diabetes mellitus (DM), patient demography, high sensitivity C-reactive protein (hsCRP), Homocysteine and other variables with IMT, to determine if these markers were correlated in diabetes (in whom technetium myocardial perfusion scan were negative) and would it be appropriate biomarkers for arthrosclerosis detection in this group of diabetics. Methods Forty patients with DM, without CHD history, were screened with stress sintigraphy imaging using 2 days stress/rest Technetium 99 tetrafosmin protocol, employing the standard Bruce protocol. Echocardiography study requested for each patient, two blood samples for hsCRP, were requested for each candidate three weeks apart, Lipid profiles, plasma homocysteine, and hemoglobin A1C were also requested. Finally Intima-media thickness were measured for all patients. Results There were no relationships between hsCRP level and DM duration or with the type of DM; also there were no relation between DM duration and homocysteine or between DM type and Homocysteine. Intimal media thickness was increased proportionally with the serum level of Homocysteine. Conclusions This study did not show any role for the inflammatory markers in predicating the presence of coronary artery disease in participants with DM, without medium size artery disease, which may support that DM is not the only player in initiating atherosclerosis. Keywords Diabetes mellitus; Inflammatory markers; C-reactive protein; Myocardial ischemia; Homocysteine; Intima-media thickness PMID:22505974

  5. Synthesis and evaluation of (18)F-trifluoroborate derivatives of triphenylphosphonium for myocardial perfusion imaging.

    PubMed

    Zhang, Zhengxing; Jenni, Silvia; Zhang, Chengcheng; Merkens, Helen; Lau, Joseph; Liu, Zhibo; Perrin, David M; Bénard, François; Lin, Kuo-Shyan

    2016-04-01

    Four trifluoroborate derivatives of phosphonium cations 2a-d were radiolabeled with fluorine-18 ((18)F) and evaluated for imaging myocardial perfusion with positron emission tomography (PET). Tracers were radiolabeled simply via (18)F-(19)F isotope exchange reaction in acidic (pH 2) aqueous solution. On average, [(18)F]2a-d were obtained in 10-17% non-decay-corrected radiochemical yield with 25.9-48.1GBq/μmol specific activity, and >96% radiochemical purity. In vitro stability study showed no decomposition of [(18)F]2a-d after being incubated in mouse plasma for up to 2h. Myocardial uptake in mice was visualized in PET images by using [(18)F]2b-d but not [(18)F]2a. [(18)F]2a-d were stable against in vivo defluorination as no significant bone uptake was observed. Despite sub-optimal heart uptake of [(18)F]2b-d, we successfully demonstrated that (18)F-(19)F isotope exchange reaction on trifluoroborates could be a promising strategy for the design of potential (18)F-labeled tracers even for intracellular targets. PMID:26922139

  6. [Preliminary evaluation of the effect of an attenuation correction method in myocardial perfusion SPECT].

    PubMed

    Cortés-Blanco, A; Fujii, C; Goris, M L

    1999-12-01

    We propose a method to assess an attenuation correction method in myocardial perfusion SPECT. Three types of images are obtained: one resulting from a classic acquisition and filtered back-projection (classic), and those resulting from acquisition with a transmission source and an iterative reconstruction, with (music) or without (hybrid) the attenuation correction factored in to compare the three types of images and classify them as normal or abnormal, a three dimensional inter-patient quantitative comparison method was used. Differences were computed as fractions of the myocardial volume in which density differences are significant by population standards. In 7 cases the cumulative difference between prone and supine in hybrid images was 124 and 45 in music images. In 10 cases the cumulative difference between classic vs music images was 279, and between classic and hybrid 86. The AC changed 4/12 cases from abnormal to normal. The attenuation correction effect was concentrated on the septal and inferior walls, but neither exclusively nor evenly among patients. The attenuation correction effectively minimizes attenuation effects by a factor of 2.7, due to a correction of at least 69%. The correction has a small but substantial effect on the results. PMID:10611567

  7. Evaluation of Respiratory Motion Effect on Defect Detection in Myocardial Perfusion SPECT: A Simulation Study

    PubMed Central

    Yang, Yu-Wen; Chen, Jyh-Cheng; He, Xin; Wang, Shyh-Jen; Tsui, Benjamin M. W.

    2010-01-01

    The objective of this study is to investigate the effects of respiratory motion (RM) on defect detection in Tc-99m sestamibi myocardial perfusion SPECT (MPS) using a phantom population that includes patient variability. Three RM patterns are included, namely breath-hold, slightly enhanced normal breathing, and deep breathing. For each RM pattern, six 4-D NCAT phantoms were generated, each with anatomical variations. Anterior, lateral and inferior myocardial defects with different sizes and contrasts were inserted. Noise-free SPECT projections were simulated using an analytical projector. Poisson noise was then added to generate noisy realizations. The projection data were reconstructed using the OS-EM algorithm with 1 and 4 subsets/iteration and at 1, 2, 3, 5, 7, and 10 iterations. Short-axis images centered at the centroid of the myocardial defect were extracted, and the channelized Hotelling observer (CHO) was applied for the detection of the defect. The CHO results show that the value of the area under the receiver operating characteristics (ROC) curve (AUC) is affected by the RM amplitude. For all the defect sizes and contrasts studied, the highest or optimal AUC values indicate maximum detectability decrease with the increase of the RM amplitude. With no respiration, the ranking of the optimal AUC value in decreasing order is anterior then lateral, and finally inferior defects. The AUC value of the lateral defect drops more severely as the RM amplitude increases compared to other defect locations. Furthermore, as the RM amplitude increases, the AUC values of the smaller defects drop more quickly than the larger ones. We demonstrated that RM affects defect detectability of MPS imaging. The results indicate that developments of optimal data acquisition methods and RM correction methods are needed to improve the defect detectability in MPS. PMID:21731107

  8. Impact of hypertension on the accuracy of exercise stress myocardial perfusion imaging for the diagnosis of coronary artery disease

    PubMed Central

    Elhendy, A; van Domburg, R T; Sozzi, F; Poldermans, D; Bax, J; Roelandt, J

    2001-01-01

    AIM—To compare the accuracy of exercise stress myocardial perfusion single photon emission computed tomography (SPECT) imaging for the diagnosis of coronary artery disease in patients with and without hypertension.
METHODS—A symptom limited bicycle exercise stress test in conjunction with 99m technetium sestamibi or tetrofosmin SPECT imaging was performed in 332 patients (mean (SD) age, 57 (10) years; 257 men, 75 women) without previous myocardial infarction who underwent coronary angiography. Of these, 137 (41%) had hypertension. Rest SPECT images were acquired 24 hours after the stress test. An abnormal scan was defined as one with reversible or fixed perfusion defects.
RESULTS—In hypertensive patients, myocardial perfusion abnormalities were detected in 79 of 102 patients with significant coronary artery disease and in nine of 35 patients without. In normotensive patients, myocardial perfusion abnormalities were detected in 104 of 138 patients with significant coronary artery disease and in 16 of 57 patients without. There were no differences between normotensive and hypertensive patients in sensitivity (77% (95% confidence interval (CI) 69% to 86%) v 75% (95% CI 68% to 83%)), specificity (74% (95% CI 60% to 89%) v 72% (95% CI 60% to 84%)), and accuracy (77% (95% CI 70% to 84%) v 74% (95% CI 68% to 80%)) of exercise SPECT for diagnosing coronary artery disease. The accuracy of SPECT was greater than electrocardiography, both in hypertensive patients (p = 0.005) and in normotensive patients (p = 0.0001). For the detection of coronary artery disease in individual vessels, sensitivity was 58% (95% CI 51% to 65%) v 57% (95% CI 51% to 64%), specificity was 86% (95% CI 82% to 90%) v 85% (95% CI 81% to 89%), and accuracy was 74% (95% CI 70% to 78%) v 74% (95% CI 70% to 78%) in patients with and without hypertension (NS).
CONCLUSIONS—In the usual clinical setting, the value of exercise myocardial perfusion scintigraphy for diagnosing

  9. Stress echocardiography: what is new and how does it compare with myocardial perfusion imaging and other modalities?

    PubMed

    Tweet, Marysia S; Arruda-Olson, Adelaide M; Anavekar, Nandan S; Pellikka, Patricia A

    2015-06-01

    Cardiovascular disease is a leading cause of morbidity and mortality, and noninvasive strategies to diagnose and risk stratify patients remain paramount in the evaluative process. Stress echocardiography is a well-established, versatile, real-time imaging modality with advantages including lack of radiation exposure, portability, and affordability. Innovative techniques in stress echocardiography include myocardial contrast echocardiography, deformation imaging, three-dimensional (3D) echocardiography, and assessment of coronary flow reserve. Myocardial perfusion imaging with single-photon emission computed tomography (SPECT) or positron emission tomography (PET) are imaging alternatives, and stress cardiac magnetic resonance imaging and coronary computed tomography (CT) angiography, including CT perfusion imaging, are emerging as newer approaches. This review will discuss recent and upcoming developments in the field of stress testing, with an emphasis on stress echocardiography while highlighting comparisons with other modalities. PMID:25911442

  10. SU-C-201-04: Quantification of Perfusion Heterogeneity Based On Texture Analysis for Fully Automatic Detection of Ischemic Deficits From Myocardial Perfusion Imaging

    SciTech Connect

    Fang, Y; Huang, H; Su, T

    2015-06-15

    Purpose: Texture-based quantification of image heterogeneity has been a popular topic for imaging studies in recent years. As previous studies mainly focus on oncological applications, we report our recent efforts of applying such techniques on cardiac perfusion imaging. A fully automated procedure has been developed to perform texture analysis for measuring the image heterogeneity. Clinical data were used to evaluate the preliminary performance of such methods. Methods: Myocardial perfusion images of Thallium-201 scans were collected from 293 patients with suspected coronary artery disease. Each subject underwent a Tl-201 scan and a percutaneous coronary intervention (PCI) within three months. The PCI Result was used as the gold standard of coronary ischemia of more than 70% stenosis. Each Tl-201 scan was spatially normalized to an image template for fully automatic segmentation of the LV. The segmented voxel intensities were then carried into the texture analysis with our open-source software Chang Gung Image Texture Analysis toolbox (CGITA). To evaluate the clinical performance of the image heterogeneity for detecting the coronary stenosis, receiver operating characteristic (ROC) analysis was used to compute the overall accuracy, sensitivity and specificity as well as the area under curve (AUC). Those indices were compared to those obtained from the commercially available semi-automatic software QPS. Results: With the fully automatic procedure to quantify heterogeneity from Tl-201 scans, we were able to achieve a good discrimination with good accuracy (74%), sensitivity (73%), specificity (77%) and AUC of 0.82. Such performance is similar to those obtained from the semi-automatic QPS software that gives a sensitivity of 71% and specificity of 77%. Conclusion: Based on fully automatic procedures of data processing, our preliminary data indicate that the image heterogeneity of myocardial perfusion imaging can provide useful information for automatic determination

  11. Applying the J-optimal channelized quadratic observer to SPECT myocardial perfusion defect detection

    NASA Astrophysics Data System (ADS)

    Kupinski, Meredith K.; Clarkson, Eric; Ghaly, Michael; Frey, Eric C.

    2016-03-01

    To evaluate performance on a perfusion defect detection task from 540 image pairs of myocardial perfusion SPECT image data we apply the J-optimal channelized quadratic observer (J-CQO). We compare AUC values of the linear Hotelling observer and J-CQO when the defect location is fixed and when it occurs in one of two locations. As expected, when the location is fixed a single channels maximizes AUC; location variability requires multiple channels to maximize the AUC. The AUC is estimated from both the projection data and reconstructed images. J-CQO is quadratic since it uses the first- and second- order statistics of the image data from both classes. The linear data reduction by the channels is described by an L x M channel matrix and in prior work we introduced an iterative gradient-based method for calculating the channel matrix. The dimensionality reduction from M measurements to L channels yields better estimates of these sample statistics from smaller sample sizes, and since the channelized covariance matrix is L x L instead of M x M, the matrix inverse is easier to compute. The novelty of our approach is the use of Jeffrey's divergence (J) as the figure of merit (FOM) for optimizing the channel matrix. We previously showed that the J-optimal channels are also the optimum channels for the AUC and the Bhattacharyya distance when the channel outputs are Gaussian distributed with equal means. This work evaluates the use of J as a surrogate FOM (SFOM) for AUC when these statistical conditions are not satisfied.

  12. Quantification of absolute myocardial perfusion at rest and during exercise with positron emission tomography after human cardiac transplantation.

    PubMed

    Krivokapich, J; Stevenson, L W; Kobashigawa, J; Huang, S C; Schelbert, H R

    1991-08-01

    The maximal exercise capacity of cardiac transplant recipients is reduced compared with that of normal subjects. To determine if this reduced exercise capacity is related to inadequate myocardial perfusion during exercise, myocardial perfusion was measured noninvasively with use of positron emission tomography and nitrogen (N)-13 ammonia. Twelve transplant recipients with no angiographic evidence of accelerated coronary atherosclerosis were studied. Serial N-13 ammonia imaging was performed at rest and during supine bicycle exercise. The results were compared with those from 10 normal volunteers with a low probability of having cardiac disease. A two-compartment kinetic model for estimating myocardial perfusion was applied to the data. Transplant recipients achieved a significant lower exercise work load than did the volunteers (42 +/- 16 vs. 128 +/- 22 W), but a higher venous lactate concentration (31.3 +/- 14.9 vs. 13.7 +/- 4.1 mg/100 ml). Despite the difference in exercise work load, there was no significant difference in the cardiac work achieved by transplant recipients and normal subjects as evidenced by similar rate-pressure products of 24,000 +/- 3,400 versus 21,300 +/- 2,800 betas/min per mm Hg, respectively. In addition, myocardial blood flow during exercise was not significantly different between the two groups (1.70 +/- 0.60 vs. 1.56 +/- 0.71 ml/min per g, respectively). This study demonstrates that the myocardial flow response to the physiologic stress of exercise is appropriate in transplant recipients and does not appear to explain the decreased exercise capacity in these patients. PMID:1856420

  13. Quantification of absolute myocardial perfusion at rest and during exercise with positron emission tomography after human cardiac transplantation

    SciTech Connect

    Krivokapich, J.; Stevenson, L.W.; Kobashigawa, J.; Huang, S.C.; Schelbert, H.R. )

    1991-08-01

    The maximal exercise capacity of cardiac transplant recipients is reduced compared with that of normal subjects. To determine if this reduced exercise capacity is related to inadequate myocardial perfusion during exercise, myocardial perfusion was measured noninvasively with use of positron emission tomography and nitrogen (N)-13 ammonia. Twelve transplant recipients with no angiographic evidence of accelerated coronary atherosclerosis were studied. Serial N-13 ammonia imaging was performed at rest and during supine bicycle exercise. The results were compared with those from 10 normal volunteers with a low probability of having cardiac disease. A two-compartment kinetic model for estimating myocardial perfusion was applied to the data. Transplant recipients achieved a significant lower exercise work load than did the volunteers (42 {plus minus} 16 vs. 128 {plus minus} 22 W), but a higher venous lactate concentration (31.3 {plus minus} 14.9 vs. 13.7 {plus minus} 4.1 mg/100 ml). Despite the difference in exercise work load, there was no significant difference in the cardiac work achieved by transplant recipients and normal subjects as evidenced by similar rate-pressure products of 24,000 {plus minus} 3,400 versus 21,300 {plus minus} 2,800 betas/min per mm Hg, respectively. In addition, myocardial blood flow during exercise was not significantly different between the two groups (1.70 {plus minus} 0.60 vs. 1.56 {plus minus} 0.71 ml/min per g, respectively). This study demonstrates that the myocardial flow response to the physiologic stress of exercise is appropriate in transplant recipients and does not appear to explain the decreased exercise capacity in these patients.

  14. Normal values for nuclear cardiology: Japanese databases for myocardial perfusion, fatty acid and sympathetic imaging and left ventricular function.

    PubMed

    Nakajima, Kenichi

    2010-04-01

    Myocardial normal databases for stress myocardial perfusion study have been created by the Japanese Society of Nuclear Medicine Working Group. The databases comprised gender-, camera rotation range- and radiopharmaceutical-specific data-sets from multiple institutions, and normal database files were created for installation in common nuclear cardiology software. Based on the electrocardiography-gated single-photon emission computed tomography (SPECT), left ventricular function, including ventricular volumes, systolic and diastolic functions and systolic wall thickening were also analyzed. Normal databases for fatty acid imaging using (123)I-beta-methyl-iodophenyl-pentadecanoic acid and sympathetic imaging using (123)I-meta-iodobenzylguanidine were also examined. This review provides lists and overviews of normal values for myocardial SPECT and ventricular function in a Japanese population. The population-specific approach is a key factor for proper diagnostic and prognostic evaluation. PMID:20108130

  15. Normal values for nuclear cardiology: Japanese databases for myocardial perfusion, fatty acid and sympathetic imaging and left ventricular function

    PubMed Central

    2010-01-01

    Myocardial normal databases for stress myocardial perfusion study have been created by the Japanese Society of Nuclear Medicine Working Group. The databases comprised gender-, camera rotation range- and radiopharmaceutical-specific data-sets from multiple institutions, and normal database files were created for installation in common nuclear cardiology software. Based on the electrocardiography-gated single-photon emission computed tomography (SPECT), left ventricular function, including ventricular volumes, systolic and diastolic functions and systolic wall thickening were also analyzed. Normal databases for fatty acid imaging using 123I-beta-methyl-iodophenyl-pentadecanoic acid and sympathetic imaging using 123I-meta-iodobenzylguanidine were also examined. This review provides lists and overviews of normal values for myocardial SPECT and ventricular function in a Japanese population. The population-specific approach is a key factor for proper diagnostic and prognostic evaluation. PMID:20108130

  16. New technique for showing the relation of tomographic myocardial perfusion images obtained with thallium-201 to the coronary arteries.

    PubMed Central

    Gibson, C J; Laird, E E; Williams, E D; Rajathurai, A; Mittra, B; Rankin, D

    1985-01-01

    A new technique has been developed for presenting myocardial tomograms that allows the observer to perceive the shape of the thallium-201 distribution directly. The surface of the myocardium was found by applying an interactive thresholding technique to a set of conventional transverse slices. Computer graphics techniques were used to display a shaded image of that surface on a television screen, showing the three dimensional shape of the myocardial surface from any chosen aspect. A set of normal preserved coronary arteries was digitised, and using scaling and transformation techniques these arteries were mapped on to the myocardial tomograms and a shaded surface image produced with superimposed coronary arteries. This provided a familiar anatomical framework for locating perfusion defects. Its value in identifying various diseased vessels was confirmed by a comparison of the tomographic findings with the angiographic findings in five individual cases. Images PMID:3876840

  17. Pulsed Doppler tissue imaging for the assessment of myocardial viability: comparison with 99mTc sestamibi perfusion imaging.

    PubMed

    Minamihaba, O; Takeishi, Y; Hirono, O; Yamauchi, S; Arimoto, T; Fukui, A; Okuyama, M; Nozaki, N; Akiyama, H; Fatema, K; Miyamoto, T; Takahashi, H; Fujiwara, S; Okada, A; Takahashi, K; Kubota, I

    2002-12-01

    The aim of the present study was to examine whether Doppler tissue imaging demonstrated comparable diagnostic performance for the detection of viable myocardium compared to myocardial perfusion imaging with Tc hexakis-2-methoxyisobutylisonitrile (MIBI). We studied 30 patients with old myocardial infarction who underwent percutaneous transluminal coronary angioplasty (PTCA). Myocardial single photon emission computed tomography (SPECT) with Tc-MIBI and two-dimensional echocardiography were carried out within 7 days before PTCA. We measured regional Tc-MIBI uptake for each myocardial segment from SPECT and peak systolic velocity and a ratio of regional pre-ejection period to regional ejection time (PEP/ET) from pulsed Doppler tissue imaging. Biplane left ventriculography was performed before interventional procedures and repeated 3 months after PTCA. Myocardial viability was determined when wall motion was improved at least one grade after PTCA. The peak systolic velocity was positively correlated with regional Tc-MIBI uptake (R =0.59, P<0.01). The PEP/ET demonstrated inverse correlation with Tc-MIBI uptake ( R=-0.59, P<0.01). Peak systolic velocity of viable segments was higher than that of non-viable segments ( P<0.05). The PEP/ET was lower in viable segments than in non-viable segments ( P<0.05). Peak systolic velocity and PEP/ET demonstrated high diagnostic accuracy for detecting viable myocardium compared with Tc-MIBI perfusion imaging (80% and 79% vs 90%). These data indicate that measurements of regional peak systolic velocity and PEP/ET by Doppler tissue imaging are useful for evaluating myocardial viability quantitatively and provide helpful information for a clinical judgment in an interventional strategy. PMID:12464785

  18. Myocardial perfusion imaging is an effective screening test for coronary artery disease in liver transplant candidates.

    PubMed

    Baker, Sally; Chambers, Charles; McQuillan, Patrick; Janicki, Piotr; Kadry, Zakiyah; Bowen, Daniel; Bezinover, Dmitri

    2015-04-01

    A reliable screening test for coronary artery disease (CAD) in liver transplant (LT) candidates with end-stage liver disease is essential because a high percentage of perioperative mortality and morbidity is CAD-related. In this study, the effectiveness of myocardial perfusion imaging (MPI) for identification of significant CAD in LT candidates was evaluated. Records of 244 patients meeting criteria for MPI were evaluated: 74 met inclusion criteria; 40 had a positive MPI and cardiology follow-up; 27 had a negative MPI and underwent LT; and seven had a negative MPI and then had coronary angiography or a significant cardiac event. A selective MPI interpretation strategy was established where MPI-positive patients were divided into high, intermediate, and low CAD risk groups. The overall incidence of CAD in this study population was 5.1% and our strategy resulted in PPV 20%, NPV 94%, sensitivity 80%, and specificity 50% for categorizing CAD risk. When applied only to the subset of patients categorized as high CAD risk, the strategy was more effective, with PPV 67%, NPV 97%, sensitivity 80%, and specificity 94%. We determined that renal dysfunction was an independent predictive factor for CAD (p < 0.0001, odds ratio = 8.1), and grades of coronary occlusion correlated significantly with chronic renal dysfunction (p = 0.0079). PMID:25604507

  19. Estimation of x-ray parameters in digital coronary angiography for compensation of myocardial perfusion measurements

    NASA Astrophysics Data System (ADS)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2008-03-01

    Coronary angiography is the primary technique for diagnosing coronary abnormalities as it is able to locate precisely the coronary artery lesions. However, the clinical relevance of an appearing stenosis is not that easy to assess. In previous work we have analyzed the myocardial perfusion by comparing basal and hyperemic coronary flow. This comparison is the basis of a Relative Coronary Flow Reserve (RCFR) measure. In a Region-of-Interest (ROI) on the angiogram 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 previous work we have presented the results of a small study of 20 patients. In this paper we present an analysis of the sensitivity of the method for variations in X-ray exposure between the two runs due to the Automatic Exposure Control (AEC) unit. The AEC is a system unit with the task to ensure a constant dose rate at the entrance of the detector by making the appropriate adaptations in X-ray factor settings for patients which range from slim to more obese. We have setup a phantom study to reveal the expected exposure variations. We present several of the developed phantoms together with a compensation strategy.

  20. Stress Myocardial Perfusion Imaging in the Emergency Department - New Techniques for Speed and Diagnostic Accuracy

    PubMed Central

    Harrison, Sheri D; Harrison, Mark A; Duvall, W Lane

    2012-01-01

    Emergency room evaluations of patients presenting with chest pain continue to rise, and these evaluations which often include cardiac imaging, are an increasing area of resource utilization in the current health system. Myocardial perfusion imaging from the emergency department remains a vital component of the diagnosis or exclusion of coronary artery disease as the etiology of chest pain. Recent advances in camera technology, and changes to the imaging protocols have allowed MPI to become a more efficient way of providing this diagnostic information. Compared with conventional SPECT, new high-efficiency CZT cameras provide a 3-5 fold increase in photon sensitivity, 1.65-fold improvement in energy resolution and a 1.7-2.5-fold increase in spatial resolution. With stress-only imaging, rest images are eliminated if stress images are normal, as they provide no additional prognostic or diagnostic value and cancelling the rest images would shorten the length of the test which is of particular importance to the ED population. The rapid but accurate triage of patients in an ED CPU is essential to their care, and stress-only imaging and new CZT cameras allow for shorter test time, lower radiation doses and lower costs while demonstrating good clinical outcomes. These changes to nuclear stress testing can allow for faster throughput of patients through the emergency department while providing a safe and efficient evaluation of chest pain. PMID:22708910

  1. Stress myocardial perfusion imaging in the emergency department--new techniques for speed and diagnostic accuracy.

    PubMed

    Harrison, Sheri D; Harrison, Mark A; Duvall, W Lane

    2012-05-01

    Emergency room evaluations of patients presenting with chest pain continue to rise, and these evaluations which often include cardiac imaging, are an increasing area of resource utilization in the current health system. Myocardial perfusion imaging from the emergency department remains a vital component of the diagnosis or exclusion of coronary artery disease as the etiology of chest pain. Recent advances in camera technology, and changes to the imaging protocols have allowed MPI to become a more efficient way of providing this diagnostic information. Compared with conventional SPECT, new high-efficiency CZT cameras provide a 3-5 fold increase in photon sensitivity, 1.65-fold improvement in energy resolution and a 1.7-2.5-fold increase in spatial resolution. With stress-only imaging, rest images are eliminated if stress images are normal, as they provide no additional prognostic or diagnostic value and cancelling the rest images would shorten the length of the test which is of particular importance to the ED population. The rapid but accurate triage of patients in an ED CPU is essential to their care, and stress-only imaging and new CZT cameras allow for shorter test time, lower radiation doses and lower costs while demonstrating good clinical outcomes. These changes to nuclear stress testing can allow for faster throughput of patients through the emergency department while providing a safe and efficient evaluation of chest pain. PMID:22708910

  2. Variable Activation of the DNA Damage Response Pathways in Patients Undergoing SPECT Myocardial Perfusion Imaging

    PubMed Central

    Hu, Shijun; Liang, Grace; Ong, Sang-Ging; Han, Leng; Sanchez-Freire, Veronica; Lee, Andrew S.; Vasanawala, Minal; Segall, George; Wu, Joseph C.

    2015-01-01

    Background Although single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) has improved the diagnosis and risk stratification of patients with suspected coronary artery disease, it remains a primary source of low dose radiation exposure for cardiac patients. To determine the biological effects of low dose radiation from SPECT MPI, we measured the activation of the DNA damage response pathways using quantitative flow cytometry and single cell gene expression profiling. Methods and Results Blood samples were collected from patients before and after SPECT MPI (n=63). Overall, analysis of all recruited patients showed no marked differences in the phosphorylation of proteins (H2AX, p53, and ATM) following SPECT. The majority of patients also had either down-regulated or unchanged expression in DNA damage response genes at both 24 and 48 hours post-SPECT. Interestingly, a small subset of patients with increased phosphorylation also had significant up-regulation of genes associated with DNA damage, whereas those with no changes in phosphorylation had significant down-regulation or no difference, suggesting that some patients may potentially be more sensitive to low dose radiation exposure. Conclusions Our findings showed that SPECT MPI resulted in a variable activation of the DNA damage response pathways. Although only a small subset of patients had increased protein phosphorylation and elevated gene expression post-imaging, continued care should be taken to reduce radiation exposure to both patients and operators. PMID:25609688

  3. Role of Perfusion at Rest in the Diagnosis of Myocardial Infarction Using Vasodilator Stress Cardiovascular Magnetic Resonance.

    PubMed

    Patel, Mita B; Mor-Avi, Victor; Kawaji, Keigo; Nathan, Sandeep; Kramer, Christopher M; Lang, Roberto M; Patel, Amit R

    2016-04-01

    In clinical practice, perfusion at rest in vasodilator stress single-photon emission computed tomography is commonly used to confirm myocardial infarction (MI) and ischemia and to rule out artifacts. It is unclear whether perfusion at rest carries similar information in cardiovascular magnetic resonance (CMR). We sought to determine whether chronic MI is associated with abnormal perfusion at rest on CMR. We compared areas of infarct and remote myocardium in 31 patients who underwent vasodilator stress CMR (1.5 T), had MI confirmed by late gadolinium enhancement (LGE scar), and coronary angiography within 6 months. Stress perfusion imaging during gadolinium first pass was followed by reversal with aminophylline (75 to 125 mg), rest perfusion, and LGE imaging. Resting and peak-stress time-intensity curves were used to obtain maximal upslopes (normalized by blood pool upslopes), which were compared between infarcted and remote myocardial regions of interest. At rest, there was no significant difference between the slopes in the regions of interest supplied by arteries with and without stenosis >70% (0.31 ± 0.16 vs 0.26 ± 0.15 1/s), irrespective of LGE scar. However, at peak stress, we found significant differences (0.20 ± 0.11 vs 0.30 ± 0.22 1/s; p <0.05), reflecting the expected stress-induced ischemia. Similarly, at rest, there was no difference between infarcted and remote myocardium (0.27 ± 0.14 vs 0.30 ± 0.17 1/s), irrespective of stenosis, but significant differences were seen during stress (0.21 ± 0.16 vs 0.28 ± 0.18 1/s; p <0.001), reflecting inducible ischemia. In conclusion, abnormalities in myocardial perfusion at rest associated with chronic MI are not reliably detectable on CMR images. Accordingly, unlike single-photon emission computed tomography, normal CMR perfusion at rest should not be used to rule out chronic MI. PMID:26830261

  4. Alterations in myocardial perfusion during exercise after isosorbide dinitrate infusion in patients with coronary disease: assessment by thallium-201 scintigraphy

    SciTech Connect

    Tono, I.; Satoh, S.; Kanaya, T.; Komatani, A.; Takahashi, K.; Tsuiki, K.; Yasui, S.

    1986-03-01

    We studied the effect of intravenous isosorbide dinitrate (ISDN) on myocardial perfusion of patients with coronary artery disease, by using exercise thallium-201 (TI-201) myocardial scintigraphy. A control study was conducted initially to assess regional myocardial perfusion rate. Left ventricular myocardium was divided into six parts: anterior, lateral, apical, inferior, posterior, and septal segments. The segmental myocardial perfusion was characterized according to TI-201 initial uptake index (IUI) of relative distribution and redistribution index (RDI) of TI-201 washout. The normal limit of IUI and RDI was established from the data of 17 persons with normal coronary arteries, and then the IUI less than or equal to 84% and the RDI greater than or equal to 1.12 was defined as abnormal. Based on IUI and RDI, each segment was characterized into three types: A type = IUI less than or equal to 84%, RDI greater than or equal to 1.12; B type = IUI less than or equal to 84%, RDI less than 1.12; and C type = IUI greater than 84%, RDI less than 1.12. ISDN was given as a dose of 0.1 mg/kg/hr, and then treadmill testing was repeated for the same duration of exercise time using the same protocol as in the control period. The segments of A type showed a significant improvement in IUI and RDI after receiving ISDN infusion, while the B and C type segments showed no change. It was also shown that the improvement of IUI and RDI of the A type segments was not as marked in multivessel disease as in cases of single-vessel disease.

  5. Adenosine and Ischemic Preconditioning

    PubMed Central

    Liang, Bruce T.; Swierkosz, Tomasz A.; Herrmann, Howard C.; Kimmel, Stephen; Jacobson, Kenneth A.

    2012-01-01

    Adenosine is released in large amounts during myocardial ischemia and is capable of exerting potent cardioprotective effects in the heart. Although these observations on adenosine have been known for a long time, how adenosine acts to achieve its anti-ischemic effect remains incompletely understood. However, recent advances on the chemistry and pharmacology of adenosine receptor ligands have provided important and novel information on the function of adenosine receptor subtypes in the cardiovascular system. The development of model systems for the cardiac actions of adenosine has yielded important insights into its mechanism of action and have begun to elucidate the sequence of signalling events from receptor activation to the actual exertion of its cardioprotective effect. The present review will focus on the adenosine receptors that mediate the potent anti-ischemic effect of adenosine, new ligands at the receptors, potential molecular signalling mechanisms downstream of the receptor, mediators for cardioprotection, and possible clinical applications in cardiovascular disorders. PMID:10607860

  6. Feasibility Study of Myocardial Perfusion and Oxygenation by Non-Contrast MRI: Comparison with PET Study in a Canine Model

    PubMed Central

    McCommis, Kyle S.; Zhang, Haosen; Herrero, Pilar; Gropler, Robert J.; Zheng, Jie

    2008-01-01

    The purpose of this study was to examine the feasibility of quantifying myocardial blood flow (MBF) and rate of myocardial oxygen consumption (MVO2) during pharmacologically induced stress without using a contrast agent. The former was measured by the arterial spin labeling (ASL) method and the later was obtained by measuring the oxygen extraction fraction (OEF) with the magnetic resonance imaging (MRI) blood oxygenation level-dependent (BOLD) effect and Fick's law. The MRI results were compared with the established positron emission tomography (PET) methods. Six mongrel dogs with induced acute moderate left coronary artery stenosis were scanned using a clinical PET and a 1.5T MRI system, in the same day. Regional MBF, myocardial OEF, and MVO2 were measured with both imaging modalities. Correlation coefficients (R2) of the three myocardial indexes (MBF, OEF, and MVO2) between MRI and PET methods ranged from 0.70 to 0.93. Bland-Altman statistics demonstrated that the estimated precision of the limits of agreement between MRI and PET measurements varied from 18% (OEF), to 37% (MBF), and 45% (MVO2). The detected changes in these indexes, at rest and during dobutamine stress, were similar between two image modalities. The proposed non-contrast MRI technique is a promising method to quantitatively assess myocardial perfusion and oxygenation. PMID:17566684

  7. Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT

    NASA Astrophysics Data System (ADS)

    Ghaly, Michael; Links, Jonathan M.; Frey, Eric C.

    2015-07-01

    Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6-5 and acquisition energy window widths of 16-22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16-22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results

  8. Non-uniform noise spatial distribution in CT myocardial perfusion and a potential solution: statistical image reconstruction

    NASA Astrophysics Data System (ADS)

    Thériault Lauzier, Pascal; Tang, Jie; Chen, Guang-Hong

    2012-03-01

    Myocardial perfusion scans are an important tool in the assessment of myocardial viability following an infarction. Cardiac perfusion analysis using CT datasets is limited by the presence of so-called partial scan artifacts. These artifacts are due to variations in beam hardening and scatter between different short-scan angular ranges. In this research, another angular range dependent effect is investigated: non-uniform noise spatial distribution. Images reconstructed using filtered backprojection (FBP) are subject to this effect. Statistical image reconstruction (SIR) is proposed as a potential solution. A numerical phantom with added Poisson noise was simulated and two swines were scanned in vivo to study the effect of FBP and SIR on the spatial uniformity of the noise distribution. It was demonstrated that images reconstructed using FBP often show variations in noise on the order of 50% between different time frames. This variation is mitigated to about 10% using SIR. The noise level is also reduced by a factor of 2 in SIR images. Finally, it is demonstrated that the measurement of quantitative perfusion metrics are generally more accurate when SIR is used instead of FBP.

  9. Physiologic evaluation of ischemia using cardiac CT: current status of CT myocardial perfusion and CT fractional flow reserve.

    PubMed

    Choi, Andrew D; Joly, Joanna M; Chen, Marcus Y; Weigold, Wm Guy

    2014-01-01

    Cardiac CT, specifically coronary CT angiography (CTA), is an established technology which detects anatomically significant coronary artery disease with a high sensitivity and negative predictive value compared with invasive coronary angiography. However, the limited ability of CTA to determine the physiologic significance of intermediate coronary stenoses remains a shortcoming compared with other noninvasive methods such as single-photon emission CT, stress echocardiography, and stress cardiac magnetic resonance. Two methods have been investigated recently: (1) myocardial CT perfusion and (2) fractional flow reserve (FFR) computed from CT (FFRCT). Improving diagnostic accuracy by combining the anatomic aspects of coronary CTA with a physiologic assessment via CT perfusion or FFRCT may reduce the need for additional testing to evaluate for ischemia, reduce downstream costs and risks associated with an invasive procedure, and lead to improved patient outcomes. Given a rapidly expanding body of research in this field, this comparative review summarizes the present literature while contrasting the benefits, limitations, and future directions in myocardial CT perfusion and FFRCT imaging. PMID:25151919

  10. Myocardial Drug Distribution Generated from Local Epicardial Application: Potential Impact of Cardiac Capillary Perfusion in a Swine Model Using Epinephrine

    PubMed Central

    Maslov, Mikhail Y.; Edelman, Elazer R.; Pezone, Matthew J.; Wei, Abraham E.; Wakim, Matthew G.; Murray, Michael R.; Tsukada, Hisashi; Gerogiannis, Iraklis S.; Groothuis, Adam; Lovich, Mark A.

    2014-01-01

    Prior studies in small mammals have shown that local epicardial application of inotropic compounds drives myocardial contractility without systemic side effects. Myocardial capillary blood flow, however, may be more significant in larger species than in small animals. We hypothesized that bulk perfusion in capillary beds of the large mammalian heart enhances drug distribution after local release, but also clears more drug from the tissue target than in small animals. Epicardial (EC) drug releasing systems were used to apply epinephrine to the anterior surface of the left heart of swine in either point-sourced or distributed configurations. Following local application or intravenous (IV) infusion at the same dose rates, hemodynamic responses, epinephrine levels in the coronary sinus and systemic circulation, and drug deposition across the ventricular wall, around the circumference and down the axis, were measured. EC delivery via point-source release generated transmural epinephrine gradients directly beneath the site of application extending into the middle third of the myocardial thickness. Gradients in drug deposition were also observed down the length of the heart and around the circumference toward the lateral wall, but not the interventricular septum. These gradients extended further than might be predicted from simple diffusion. The circumferential distribution following local epinephrine delivery from a distributed source to the entire anterior wall drove drug toward the inferior wall, further than with point-source release, but again, not to the septum. This augmented drug distribution away from the release source, down the axis of the left ventricle, and selectively towards the left heart follows the direction of capillary perfusion away from the anterior descending and circumflex arteries, suggesting a role for the coronary circulation in determining local drug deposition and clearance. The dominant role of the coronary vasculature is further suggested by

  11. Chest Pain with Normal Thallium-201 Myocardial Perfusion Image – Is It Really Normal?

    PubMed Central

    Liu, Pang-Yen; Lin, Wen-Yu; Lin, Li-Fan; Lin, Chin-Sheng; Lin, Wei-Shiang; Cheng, Shu-Meng; Yang, Shih-Ping; Liou, Jun-Ting

    2016-01-01

    Background Thallium-201 myocardial perfusion image (MPI) is commonly used to detect coronary artery disease in patients with chest pain. Although a normal thallium-201 MPI result is generally considered to be a good prognosis and further coronary angiogram is not recommended, there are still a few patients who suffer from unexpected acute coronary events. The aim of this study was to investigate the clinical prognosis in patients with normal thallium-201 MPI. Methods From January 2006 to August 2012, a total 22,003 patients undergoing thallium-201 MPI in one tertiary center were screened. Of these, 8092 patients had normal results and were investigated retrospectively. During follow-up, 54 patients underwent coronary angiogram because of refractory typical angina pectoris or unexpected acute coronary events. These 54 patients were divided into 2 groups: group I consisted of 26 (48.1%) patients with angiography-proven significant coronary artery stenosis, and group II consisted of 28 (51.9%) patients without significant stenosis. Results Patients in group I had a higher prevalence of prior coronary stenting and electrocardiographic features of ST depression compared with patients in group II. The multivariate analysis demonstrated that both prior coronary stenting and ST depression were risk predictors of unexpected acute coronary events in the patients with normal thallium-201 MPI [odds ratio (OR), 5.93; 95% confidence interval (CI): 1.03-34.06, p = 0.05 and OR, 7.10; 95% CI: 1.28-39.51, p = 0.03,respectively]. Conclusions Although there is a low incidence of unexpected acute coronary events in patients with chest pain and normal thallium-201 MPI, physicians should be aware of the potentials risk in certain patients in this specific population. PMID:27274174

  12. A comparison of cost functions for data-driven motion estimation in myocardial perfusion SPECT imaging

    NASA Astrophysics Data System (ADS)

    Mukherjee, Joyeeta Mitra; Pretorius, P. H.; Johnson, K. L.; Hutton, Brian F.; King, Michael A.

    2011-03-01

    In myocardial perfusion SPECT imaging patient motion during acquisition causes severe artifacts in about 5% of studies. Motion estimation strategies commonly used are a) data-driven, where the motion may be determined by registration and checking consistency with the SPECT acquisition data, and b) external surrogate-based, where the motion is obtained from a dedicated motion-tracking system. In this paper a data-driven strategy similar to a 2D-3D registration scheme with multiple views is investigated, using a partially reconstructed heart for the 3D model. The partially-reconstructed heart has inaccuracies due to limited angle artifacts resulting from using only a part of the SPECT projections acquired while the patient maintained the same pose. The goal of this paper is to compare the performance of different cost-functions in quantifying consistency with the SPECT projection data in a registration-based scheme for motion estimation as the image-quality of the 3D model degrades. Six intensity-based metrics- Mean-squared difference (MSD), Mutual information (MI), Normalized Mutual information NMI), Pattern intensity (PI), normalized cross-correlation (NCC) and Entropy of the difference (EDI) were studied. Quantitative and qualitative analysis of the performance is reported using Monte-Carlo simulations of a realistic heart phantom including degradation factors such as attenuation, scatter and collimator blurring. Further the image quality of motion-corrected images using data-driven motion estimates was compared to that obtained using the external motion-tracking system in acquisitions of anthropomorphic phantoms and patient studies in a real clinical setting. Pattern intensity and Normalized Mutual Information cost functions were observed to have the best performance in terms of lowest average position error and stability with degradation of image quality of the partial reconstruction in simulations and anthropomorphic phantom acquisitions. In patient studies

  13. Design of a digital phantom population for myocardial perfusion SPECT imaging research

    PubMed Central

    Ghaly, Michael; Du, Yong; Fung, George S.K.; Tsui, Benjamin M.W.; Links, Jonathan M.; Frey, Eric

    2014-01-01

    Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the 3D XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included 3 variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET Monte Carlo code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk in the

  14. Optimal left ventricular lead position assessed with phase analysis on gated myocardial perfusion SPECT

    PubMed Central

    Boogers, Mark J.; Chen, Ji; van Bommel, Rutger J.; Borleffs, C. Jan Willem; Dibbets-Schneider, Petra; van der Hiel, Bernies; Al Younis, Imad; Schalij, Martin J.; van der Wall, Ernst E.; Garcia, Ernest V.

    2010-01-01

    Purpose The aim of the current study was to evaluate the relationship between the site of latest mechanical activation as assessed with gated myocardial perfusion SPECT (GMPS), left ventricular (LV) lead position and response to cardiac resynchronization therapy (CRT). Methods The patient population consisted of consecutive patients with advanced heart failure in whom CRT was currently indicated. Before implantation, 2-D echocardiography and GMPS were performed. The echocardiography was performed to assess LV end-systolic volume (LVESV), LV end-diastolic volume (LVEDV) and LV ejection fraction (LVEF). The site of latest mechanical activation was assessed by phase analysis of GMPS studies and related to LV lead position on fluoroscopy. Echocardiography was repeated after 6 months of CRT. CRT response was defined as a decrease of ≥15% in LVESV. Results Enrolled in the study were 90 patients (72% men, 67±10 years) with advanced heart failure. In 52 patients (58%), the LV lead was positioned at the site of latest mechanical activation (concordant), and in 38 patients (42%) the LV lead was positioned outside the site of latest mechanical activation (discordant). CRT response was significantly more often documented in patients with a concordant LV lead position than in patients with a discordant LV lead position (79% vs. 26%, p<0.01). After 6 months, patients with a concordant LV lead position showed significant improvement in LVEF, LVESV and LVEDV (p<0.05), whereas patients with a discordant LV lead position showed no significant improvement in these variables. Conclusion Patients with a concordant LV lead position showed significant improvement in LV volumes and LV systolic function, whereas patients with a discordant LV lead position showed no significant improvements. PMID:20953608

  15. Design of a digital phantom population for myocardial perfusion SPECT imaging research.

    PubMed

    Ghaly, Michael; Du, Yong; Fung, George S K; Tsui, Benjamin M W; Links, Jonathan M; Frey, Eric

    2014-06-21

    Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the three-dimensional XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included three variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET MC code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk

  16. Design of a digital phantom population for myocardial perfusion SPECT imaging research

    NASA Astrophysics Data System (ADS)

    Ghaly, Michael; Du, Yong; Fung, George S. K.; Tsui, Benjamin M. W.; Links, Jonathan M.; Frey, Eric

    2014-06-01

    Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the three-dimensional XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included three variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET MC code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk in

  17. The prevalence of a false-positive myocardial perfusion stress SPET test in a skinny patient, induced by projection truncation.

    PubMed

    Tsougos, Ioannis; Alexiou, Sotiria; Theodorou, Kiki; Valotassiou, Varvara; Georgoulias, Panagiotis

    2015-01-01

    During the last decade, technical developments in myocardial perfusion single photon emission tomography (SPET) imaging systems have significantly improved the accuracy of diagnosing coronary artery disease. Nevertheless, the patient's position and/or the acquisition protocol can affect the studies' quality, possibly leading to misdiagnoses. In HJNM and in other journals the importance of proper positioning of the heart of the patient to be examined by myocardial perfusion SPET stress/rest testing, has been emphasized. According to our knowledge, only three cases of truncation artifact during SPET myocardial perfusion imaging acquired with original SPET cameras, related to improper positioning in very thin patients, have been reported. In all cases, patients were examined according to a single day stress/rest technetium-99m-sestamibi protocol, using a dual 90 degree detector system, equipped with high resolution, parallel-hole collimators. However, several published manuscripts have underlined the significance of appropriate patients' positioning in myocardial perfusion scintigraphy using dedicated, cadmium-zinc-telluride (CZT) or small field-of-view cardiac SPET systems. A typical case is that of a 47 years old man (height 187cm, weight 67kg), heavy smoker, with atypical chest pain. He exercised very well according to the Bruce protocol, achieving 95% of maximal age-predicted heart-rate and a technetium-99m-tetrofosmin ((99m)Tc-TF) myocardial perfusion imaging with 370MBq of (99m)Tc-TF followed with a dual head camera (Infinia GE, USA), equipped with low-energy, high-resolution, parallel-hole collimators at 90° (L-mode configuration). Projection images were obtained from 45° RAO to 45° LPO position, in step and shoot mode (60 projections, 30sec per projection; matrix 64×64 and zoom 1.3). Auto body contour was not used. Unprocessed raw data, showed neither patient motion nor significant extracardiac activity that could result in false positive defects on

  18. 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

  19. Review of Cardiovascular Imaging in the Journal of Nuclear Cardiology in 2015-Part 2 of 2: Myocardial perfusion imaging.

    PubMed

    Hage, Fadi G; AlJaroudi, Wael A

    2016-06-01

    In 2015, the Journal of Nuclear Cardiology (®) published many high-quality articles. In this series, we will summarize key articles that have appeared in the Journal last year to provide for the interested reader a quick review of the advancements that have recently occurred in the field. In the first article of this 2-part series, we concentrated on publications dealing with plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance. This review will focus on myocardial perfusion imaging summarizing advances in the field including in diagnosis, prognosis, and appropriate use. PMID:26892251

  20. [Coronary artery disease, myocardial perfusion and ventricular function in Q-wave and non-Q-wave myocardial infarcts].

    PubMed

    Macieira-Coelho, E; Garcia-Alves, M; da Costa, B; Cantinho, G; Pedro, P; Dionisio, I; Gouveia, A; de Padua, F

    1997-04-01

    Controversy remains in considering non-Q wave myocardial infarction (NQMI) a distinct pathophysiological entity of Q wave myocardial infarction (QMI). In order to analyze the severity of coronary artery disease, extension of myocardial scar or myocardial ischemia and ventricular function, 78 consecutive patients with QMI and 32 with NQMI, mean age 55.4 +/- 8.5, not submitted to thrombolytic therapy, were studied. Coronary angiography, exercise thallium scintigraphy and radionuclide ventriculography were performed in all at least within 3 months of a prior myocardial infarction. In the present study the occurrence of QMI was significantly more frequent in older patients than NQMI. There was no prevalence of occlusion either in the right, left circumflex or left anterior descending coronary arteries in both groups. Ejection fraction, degree of occlusion and presence of collateral circulation showed an equal prevalence in QMI and NQMI patients. A higher incidence of multivessel disease was found in NQMI that had less necrosis than QMI patients. The prevalence of exercise induced thallium-201 redistribution defects within the infarct zone was substantially higher and involved more scar segments in NQMI patients. Physiological and clinical consequences of coronary thrombosis depends on the size and the number of diseased arteries, the approach the pathophysiologic consequences of coronary disease in terms of fractal structure has been suggested. A pronounced heterogeneity in regional myocardial blood flow in a fractal branching arterial network may be responsible for the pathophysiologic differences of coronary thrombosis between Q-wave and non Q-wave infarction. PMID:9341032

  1. Relation between regional myocardial uptake of /sup 82/Rb and perfusion: absolute reduction of cation uptake in ischemia

    SciTech Connect

    Selwyn, A.P.; Allan, R.M.; L'Abbate, A.; Horlock, P.; Camici, P.; Clark, J.; O'Brien, H.A.; Grant, P.M.

    1982-07-01

    Experiments were undertaken using /sup 82/Rb and position tomography to examine the relation between myocardial perfusion and cation uptake during acute ischemia. /sup 82/Rb was repeatedly eluted from a /sup 82/Sr-/sup 82/Rb generator. In six dogs emission tomograms were used to measure the delivered arterial and myocardial concentrations at rest and after coronary stenosis, stress and ischemia. There was a poor overall relation between regional myocardial uptake and flow measured by microspheres and a large individual variability. Extraction of /sup 82/Rb was inversely related to flow. Significant regional reduction of cation uptake was detected in the tomograms when regional flow decreased by more than 35 percent. This reduction was significantly greater when ischemia was present. A small but significantly greater when ischemia was present. A small but significant decrease (33.0 +/- 9.1 percent, mean +/- standard deviation) in the myocardial uptake of /sup 82/Rb was detected only when flow was increased by more than 120 percent in relation to a control area after administration of dypiridamole. The technique using /sup 82/Rb and tomography was applied in five volunteers and five patients with angina pectoris and coronary artery disease. Myocardial tomograms recorded at rest and after exercise in the volunteers showed homogeneous uptake of cation in reproducible and repeatable scans. In contrast, the patients with coronary artery disease showed an absolute mean decrease of 36 +/- 14 percent in regional myocardial uptake of /sup 82/Rb after exercise. These abnormalities persisted in serial tomograms for more than 20 minutes after the symptoms and electrocardiographic signs of ischemia.

  2. Acceptance of Combined Coronary CT Angiography and Myocardial CT Perfusion versus Conventional Coronary Angiography in Patients with Coronary Stents—Intraindividual Comparison

    PubMed Central

    Martus, Peter; Laule, Michael; Dewey, Marc; Schönenberger, Eva

    2015-01-01

    Objectives To evaluate how well patients with coronary stents accept combined coronary computed tomography angiography (CTA) and myocardial CT perfusion (CTP) compared with conventional coronary angiography (CCA). Background While combined CTA and CTP may improve diagnostic accuracy compared with CTA alone, patient acceptance of CTA/CTP remains to be defined. Methods A total of 90 patients with coronary stents prospectively underwent CTA/CTP (both with contrast agent, CTP with adenosine) and CCA as part of the CARS-320 study. In this group, an intraindividual comparison of patient acceptance of CTA, CTP, and CCA was performed. Results CTP was experienced to be significantly more painful than CTA (p<0.001) and was associated with a higher frequency of dyspnea (p<0.001). Comparison of CTA/CTP with CCA revealed no significant differences in terms of pain (p = 0.141) and comfort (p = 0.377). Concern before CTA/CTP and CCA and overall satisfaction were likewise not significantly different (p = 0.097 and p = 0.123, respectively). Nevertheless, about two thirds (n = 60, 68%) preferred CTA/CTP to CCA (p<0.001). Moreover, patients felt less helpless during CTA/CTP than during CCA (p = 0.026). Lack of invasiveness and absence of pain were the most frequently mentioned advantages of CTA/CTP over CCA in our patient population. Conclusions CCA and combined CTA/CTP are equally well accepted by patients; however, more patients prefer CTA/CTP. CTP was associated with more intense pain than CTA and more frequently caused dyspnea than CTA alone. Trial Registration ClinicalTrials.gov NCT00967876 PMID:26327127

  3. An efficient polyenergetic SART (pSART) reconstruction algorithm for quantitative myocardial CT perfusion

    SciTech Connect

    Lin, Yuan Samei, Ehsan

    2014-02-15

    Purpose: In quantitative myocardial CT perfusion imaging, beam hardening effect due to dense bone and high concentration iodinated contrast agent can result in visible artifacts and inaccurate CT numbers. In this paper, an efficient polyenergetic Simultaneous Algebraic Reconstruction Technique (pSART) was presented to eliminate the beam hardening artifacts and to improve the CT quantitative imaging ability. Methods: Our algorithm made threea priori assumptions: (1) the human body is composed of several base materials (e.g., fat, breast, soft tissue, bone, and iodine); (2) images can be coarsely segmented to two types of regions, i.e., nonbone regions and noniodine regions; and (3) each voxel can be decomposed into a mixture of two most suitable base materials according to its attenuation value and its corresponding region type information. Based on the above assumptions, energy-independent accumulated effective lengths of all base materials can be fast computed in the forward ray-tracing process and be used repeatedly to obtain accurate polyenergetic projections, with which a SART-based equation can correctly update each voxel in the backward projecting process to iteratively reconstruct artifact-free images. This approach effectively reduces the influence of polyenergetic x-ray sources and it further enables monoenergetic images to be reconstructed at any arbitrarily preselected target energies. A series of simulation tests were performed on a size-variable cylindrical phantom and a realistic anthropomorphic thorax phantom. In addition, a phantom experiment was also performed on a clinical CT scanner to further quantitatively validate the proposed algorithm. Results: The simulations with the cylindrical phantom and the anthropomorphic thorax phantom showed that the proposed algorithm completely eliminated beam hardening artifacts and enabled quantitative imaging across different materials, phantom sizes, and spectra, as the absolute relative errors were reduced

  4. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT.

    PubMed

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2014-04-01

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)(-1), cardiac output = 3, 5, 8 L min(-1)). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This

  5. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT

    NASA Astrophysics Data System (ADS)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2014-04-01

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)-1, cardiac output = 3, 5, 8 L min-1). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This suggests that

  6. Novel synthesis and initial preclinical evaluation of (18)F-[FDG] labeled rhodamine: a potential PET myocardial perfusion imaging agent.

    PubMed

    AlJammaz, Ibrahim; Al-Otaibi, Basim; AlHindas, Hussein; Okarvi, Subhani M

    2015-10-01

    Myocardial perfusion imaging is one of the most commonly performed investigations in nuclear medicine studies. Due to the clinical importance of [(18)F]-fluoro-2-deoxy-D-glucose ([(18)F]-FDG) and its availability in almost every PET center, a new radiofluorinated [(18)F]-FDG-rhodamine conjugate was synthesized using [(18)F]-FDG as a prosthetic group. In a convenient and simple one-step radiosynthesis, [(18)F]-FDG-rhodamine conjugate was prepared in quantitative radiochemical yields, with total synthesis time of nearly 20 min and radiochemical purity of greater than 98%, without the need for HPLC purification, which make these approaches amenable for automation. Biodistribution studies in normal rats at 60 min post-injection demonstrated a high uptake in the heart (>11% ID/g) and favorable pharmacokinetics. Additionally, [(18)F]-FDG-rhodamine showed an extraction value of 27.63%±5.12% in rat hearts. These results demonstrate that [(18)F]-FDG-rhodamine conjugate may be useful as an imaging agent for the positron emission tomography evaluation of myocardial perfusion. PMID:26160144

  7. Optimization of OSEM parameters in myocardial perfusion imaging reconstruction as a function of body mass index: a clinical approach*

    PubMed Central

    de Barros, Pietro Paolo; Metello, Luis F.; Camozzato, Tatiane Sabriela Cagol; Vieira, Domingos Manuel da Silva

    2015-01-01

    Objective The present study is aimed at contributing to identify the most appropriate OSEM parameters to generate myocardial perfusion imaging reconstructions with the best diagnostic quality, correlating them with patients’ body mass index. Materials and Methods The present study included 28 adult patients submitted to myocardial perfusion imaging in a public hospital. The OSEM method was utilized in the images reconstruction with six different combinations of iterations and subsets numbers. The images were analyzed by nuclear cardiology specialists taking their diagnostic value into consideration and indicating the most appropriate images in terms of diagnostic quality. Results An overall scoring analysis demonstrated that the combination of four iterations and four subsets has generated the most appropriate images in terms of diagnostic quality for all the classes of body mass index; however, the role played by the combination of six iterations and four subsets is highlighted in relation to the higher body mass index classes. Conclusion The use of optimized parameters seems to play a relevant role in the generation of images with better diagnostic quality, ensuring the diagnosis and consequential appropriate and effective treatment for the patient. PMID:26543282

  8. Association between heart rate at rest and myocardial perfusion in patients with acute myocardial infarction undergoing cardiac rehabilitation – a pilot study

    PubMed Central

    Uematsu, Mariko; Ashikaga, Kohei; Yoneyama, Kihei; Kida, Keisuke; Suzuki, Kengo; Omiya, Kazuto; Harada, Tomoo; Banach, Maciej; Miyake, Fumihiko

    2012-01-01

    Introduction This study was conducted to determine if there was a link among heart rate at rest (rHR), muscle volume changes, and single photon emission computed tomography (SPECT) parameters after 6-month cardiac rehabilitation in patients with acute myocardial infarction (AMI). Material and methods Twenty-nine consecutive AMI patients (mean age: 63.0 ±9.1 years) who received appropriate percutaneous coronary intervention on admission were enrolled. 99mTc-Sestamibi myocardial SPECT images were obtained at the early (30 min) and delayed (4 h) phases after tracer injection at 2 weeks (0M) and 6 months (6M) after the onset of AMI. Within a few days of SPECT, all patients underwent cardiopulmonary exercise test for evaluation of cardiac rehabilitation effects. Before the initiation of exercise test, leg muscle volume was measured. All patients were stratified into the ≥ 70 beats per minute (bpm) (n = 15) or < 70 bpm (n = 14) group based on rHR at 6M. Results There were no significant differences in the recanalization time, peak cardiac enzyme, or initial left ventricular ejection fraction between the two groups. After the 6-month training, the muscle volume changes in the lower limbs (< 70 bpm, 0.23 ±0.22; ≥ 70 bpm, –0.07 ±0.26, p < 0.05) were significantly greater in the < 70 bpm group than the ≥ 70 bpm group. The decreased rate of rHR had a significant correlation with the improved global severity (r = 0.62, p = 0.001) and extent (r = 0.48, p = 0.017) of left ventricle evaluated by 99mTc-Sestamibi myocardial SPECT delayed phase. Conclusions The result of this preliminary study demonstrated that improved myocardial perfusion was closely related to decreased rHR after cardiac rehabilitation. PMID:23056072

  9. Optimization of the filter parameters in (99m)Tc myocardial perfusion SPECT studies: the formulation of flowchart.

    PubMed

    Shibutani, Takayuki; Onoguchi, Masahisa; Yamada, Tomoki; Kamida, Hiroki; Kunishita, Kohei; Hayashi, Yuuki; Nakajima, Tadashi; Kinuya, Seigo

    2016-06-01

    Myocardial perfusion single photon emission computed tomography (SPECT) is typically subject to a variation in image quality due to the use of different acquisition protocols, image reconstruction parameters and image display settings by each institution. One of the principal image reconstruction parameters is the Butterworth filter cut-off frequency, a parameter strongly affecting the quality of myocardial images. The objective of this study was to formulate a flowchart for the determination of the optimal parameters of the Butterworth filter for filtered back projection (FBP), ordered subset expectation maximization (OSEM) and collimator-detector response compensation OSEM (CDR-OSEM) methods using the evaluation system of the myocardial image based on technical grounds phantom. SPECT studies were acquired for seven simulated defects where the average counts of the normal myocardial components of 45° left anterior oblique projections were approximately 10-120 counts/pixel. These SPECT images were then reconstructed by FBP, OSEM and CDR-OSEM methods. Visual and quantitative assessment of short axis images were performed for the defect and normal parts. Finally, we formulated a flowchart indicating the optimal image processing procedure for SPECT images. Correlation between normal myocardial counts and the optimal cut-off frequency could be represented as a regression expression, which had high or medium coefficient of determination. We formulated the flowchart in order to optimize the image reconstruction parameters based on a comprehensive assessment, which enabled us to perform objectively processing. Furthermore, the usefulness of image reconstruction using the flowchart was demonstrated by a clinical case. PMID:27052439

  10. Significance of perfusion of the infarct related coronary artery for susceptibility to ventricular tachyarrhythmias in patients with previous myocardial infarction.

    PubMed Central

    Huikuri, H. V.; Koistinen, M. J.; Airaksinen, K. E.; Ikäheimo, M. J.

    1996-01-01

    OBJECTIVE--To study the significance of perfusion of the infarct related coronary artery for susceptibility to ventricular tachyarrhythmias in patients with a remote myocardial infarction. SETTING--Tertiary referral cardiac centre. METHODS--Angiographic filling of the infarct related artery was assessed in a consecutive series of 85 patients with different susceptibilities to ventricular tachyarrhythmias after previous (> 3 months) Q wave myocardial infarction: 30 patients had a history of cardiac arrest (n = 16) or sustained ventricular tachycardia (n = 14), and sustained ventricular tachyarrhythmia was inducible in these by programmed electrical stimulation (arrhythmia group); 47 patients had no clinical arrhythmic events and no inducible ventricular tachyarrhythmias during programmed ventricular stimulation (control group). Eight patients without a history of any arrhythmic events were inducible into ventricular tachycardia. RESULTS--The patients in the arrhythmia group were older (63 (SD 8) years) than the control patients (59 (6) years, P < 0.05), and had larger left ventricular volumes in cineangiography (P < 0.01), but ejection fraction, severity of left ventricular wall motion abnormalities, previous thrombolytic therapy, and time from previous infarction did not differ between the groups. Patients with susceptibility to ventricular tachyarrhythmias more often had a totally occluded infarct related artery on angiography (77%) than patients without arrhythmia susceptibility (21%) (P < 0.001), and complete collateral filling of the infarct artery in cases without complete anterograde filling was less common in the arrhythmia group than in the control group (P < 0.001). Patients without a history of malignant arrhythmia but with inducible ventricular tachyarrhythmia also had no or poor perfusion of the infarct artery more often than the patients without inducible arrhythmia (P < 0.001). Logistic multiple regression showed that no or poor anterograde or

  11. Biodistribution and radiodosimetry of a novel myocardial perfusion tracer 123I-CMICE-013 in healthy rats

    PubMed Central

    2014-01-01

    Background 123I-CMICE-013 is a novel radiotracer previously reported to have promising characteristics for single-photon emission computed tomography (SPECT) myocardial perfusion imaging. We evaluated the biokinetics and radiodosimetry of this rotenone-like 123I-labeled tracer in a microSPECT imaging-based study. Methods 37 to 111 MBq of 123I-CMICE-013 was synthesized and administered intravenously to 14 healthy rats. Images were acquired with a microSPECT/CT camera at various time intervals and reconstructed to allow activity quantification in the tissues of interest. Radiation dosage resulted from the injection of 123I-CMICE-013 was estimated base on the biodistribution data. Tissue uptake values from image analysis were verified by gamma-counting dissected organs ex vivo. Results The heart/stomach and heart/intestine uptake ratios peaked shortly after the injection of 123I-CMICE-013, meanwhile the heart/liver ratio reached 2 as early as at 23 min post-injection. Little activity was observed in the lung and overnight clearance was significant in most of the measured tissues. The radiation dosimetry analysis based on the time-activity curves provided an estimate of the effective human dose of 6.99E-03 mSv/MBq using ICRP 60 and 7.15E-03 mSv/MBq using ICRP 103, which is comparable to the popular myocardium perfusion imaging (MPI) agents such as 99mTc-tetrofosmin and 99mTc-sestamibi, as well as other 123I-based radiotracers. Conclusions 123I-CMICE-013 demonstrated desirable characteristics in its biokinetic and radiodosimetric profiles, supporting its potential application as a novel myocardial perfusion imaging agent. PMID:24620906

  12. Assessment of global myocardial perfusion reserve using cardiovascular magnetic resonance of coronary sinus flow at 3 Tesla

    PubMed Central

    2014-01-01

    Background Despite increasing clinical use, there is limited data regarding regadenoson in stress perfusion cardiovascular magnetic resonance (CMR). In particular, given its long half-life the optimal stress protocol remains unclear. Although Myocardial Perfusion Reserve (MPR) may provide additive prognostic information, current techniques for its measurement are cumbersome and challenging for routine clinical practice. The aims of this study were: 1) To determine the feasibility of MPR quantification during regadenoson stress CMR by measurement of Coronary Sinus (CS) flow; and 2) to investigate the role of aminophylline reversal during regadenoson stress-CMR. Methods 117 consecutive patients with possible myocardial ischemia were prospectively enrolled. Perfusion imaging was performed at 1 minute and 15 minutes after administration of 0.4 mg regadenoson. A subgroup of 41 patients was given aminophylline (100 mg) after stress images were acquired. CS flow was measured using phase-contrast imaging at baseline (pre CS flow), and immediately after the stress (peak CS flow) and rest (post CS flow) perfusion images. Results CS flow measurements were obtained in 92% of patients with no adverse events. MPR was significantly underestimated when calculated as peak CS flow/post CS flow as compared to peak CS flow/pre CS flow (2.43 ± 0.20 vs. 3.28 ± 0.32, p = 0.03). This difference was abolished when aminophylline was administered (3.35 ± 0.44 vs. 3.30 ± 0.52, p = 0.95). Impaired MPR (peak CS flow/pre CS flow <2) was associated with advanced age, diabetes, current smoking and higher Framingham risk score. Conclusions Regadenoson stress CMR with MPR measurement from CS flow can be successfully performed in most patients. This measurement of MPR appears practical to perform in the clinical setting. Residual hyperemia is still present even 15 minutes after regadenoson administration, at the time of resting-perfusion acquisition, and is completely

  13. 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.

  14. 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.

  15. Dynamic myocardial perfusion in a porcine balloon-induced ischemia model using a prototype spectral detector CT

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Fares, Anas; Levi, Jacob; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2015-03-01

    Myocardial CT perfusion (CTP) imaging is an application that should greatly benefit from spectral CT through the significant reduction of beam hardening (BH) artifacts using mono-energetic (monoE) image reconstructions. We used a prototype spectral detector CT (SDCT) scanner (Philips Healthcare) and developed advanced processing tools (registration, segmentation, and deconvolution-based flow estimation) for quantitative myocardial CTP in a porcine ischemia model with different degrees of coronary occlusion using a balloon catheter. The occlusion severity was adjusted with fractional flow reserve (FFR) measurements. The SDCT scanner is a single source, dual-layer detector system, which allows simultaneous acquisitions of low and high energy projections, hence enabling accurate projection-based material decomposition and effective reduction of BH-artifacts. In addition, the SDCT scanner eliminates partial scan artifacts with fast (0.27s), full gantry rotation acquisitions. We acquired CTP data under different hemodynamic conditions and reconstructed conventional 120kVp images and projection-based monoenergetic (monoE) images for energies ranging from 55keV-to-120keV. We computed and compared myocardial blood flow (MBF) between different reconstructions. With balloon completely deflated (FFR=1), we compared the mean attenuation in a myocardial region of interest before iodine arrival and at peak iodine enhancement in the left ventricle (LV), and we found that monoE images at 70keV effectively minimized the difference in attenuation, due to BH, to less than 1 HU compared to 14 HU with conventional 120kVp images. Flow maps under baseline condition (FFR=1) were more uniform throughout the myocardial wall at 70keV, whereas with 120kVp data about 12% reduction in blood flow was noticed on BH-hypoattenuated areas compared to other myocardial regions. We compared MBF maps at different keVs under an ischemic condition (FFR < 0.7), and we found that flow

  16. The Benefits of Prone SPECT Myocardial Perfusion Imaging in Reducing Both Artifact Defects and Patient Radiation Exposure

    PubMed Central

    Stathaki, Maria; Koukouraki, Sophia; Papadaki, Emmanouela; Tsaroucha, Angeliki; Karkavitsas, Nikolaos

    2015-01-01

    Background Prone imaging has been demonstrated to minimize diaphragmatic and breast tissue attenuation. Objectives To determine the role of prone imaging on the reduction of unnecessary rest perfusion studies and coronary angiographies performed, thus decreasing investigation time and radiation exposure. Methods We examined 139 patients, 120 with an inferior wall and 19 with an anterior wall perfusion defect that might represented attenuation artifact. Post-stress images were acquired in both the supine and prone position. Coronary angiography was used as the “gold standard” for evaluating coronary artery patency. The study was terminated and rest imaging was obviated in the presence of complete improvement of the defect in the prone position. Quantitative interpretation was performed. Results were compared with clinical data and coronary angiographic findings. Results Prone acquisition correctly revealed defect improvement in 89 patients (89/120) with inferior wall and 12 patients (12/19) with anterior wall attenuation artifact. Quantitative analysis demonstrated statistically significant difference in the mean summed stress scores (SSS) of supine and mean SSS of prone studies in patients with disappearing inferior wall defect in the prone position and patent right coronary artery (true negative results). The mean difference between SSS in supine and in prone position was higher with disappearing than with remaining defects. Conclusion Technetium-99m (Tc-99m) tetrofosmin myocardial perfusion imaging with the patient in the prone position overcomes soft tissue attenuation; moreover it provides an inexpensive, accurate approach to limit the number of unnecessary rest perfusion studies and coronary angiographies performed. PMID:26559981

  17. Detection and severity classification of extracardiac interference in {sup 82}Rb PET myocardial perfusion imaging

    SciTech Connect

    Orton, Elizabeth J. Kemp, Robert A. de; Glenn Wells, R.; Al Harbi, Ibraheem; Klein, Ran; Beanlands, Rob S. B.

    2014-10-15

    Purpose: Myocardial perfusion imaging (MPI) is used for diagnosis and prognosis of coronary artery disease. When MPI studies are performed with positron emission tomography (PET) and the radioactive tracer rubidium-82 chloride ({sup 82}Rb), a small but non-negligible fraction of studies (∼10%) suffer from extracardiac interference: high levels of tracer uptake in structures adjacent to the heart which mask the true cardiac tracer uptake. At present, there are no clinically available options for automated detection or correction of this problem. This work presents an algorithm that detects and classifies the severity of extracardiac interference in {sup 82}Rb PET MPI images and reports the accuracy and failure rate of the method. Methods: A set of 200 {sup 82}Rb PET MPI images were reviewed by a trained nuclear cardiologist and interference severity reported on a four-class scale, from absent to severe. An automated algorithm was developed that compares uptake at the external border of the myocardium to three thresholds, separating the four interference severity classes. A minimum area of interference was required, and the search region was limited to that facing the stomach wall and spleen. Maximizing concordance (Cohen’s Kappa) and minimizing failure rate for the set of 200 clinician-read images were used to find the optimal population-based constants defining search limit and minimum area parameters and the thresholds for the algorithm. Tenfold stratified cross-validation was used to find optimal thresholds and report accuracy measures (sensitivity, specificity, and Kappa). Results: The algorithm was capable of detecting interference with a mean [95% confidence interval] sensitivity/specificity/Kappa of 0.97 [0.94, 1.00]/0.82 [0.66, 0.98]/0.79 [0.65, 0.92], and a failure rate of 1.0% ± 0.2%. The four-class overall Kappa was 0.72 [0.64, 0.81]. Separation of mild versus moderate-or-greater interference was performed with good accuracy (sensitivity

  18. ATP sensitive K(+) channels are critical for maintaining myocardial perfusion and high energy phosphates in the failing heart.

    PubMed

    Jameel, Mohammad N; Xiong, Qiang; Mansoor, Abdul; Bache, Robert J; Zhang, Jianyi

    2016-03-01

    Congestive heart failure (CHF) is associated with intrinsic alterations of mitochondrial oxidative phosphorylation which lead to increased myocardial cytosolic free ADP. ATP sensitive K(+) channels (KATP) act as metabolic sensors that are important for maintaining coronary blood flow (MBF) and in mediating the response of the myocardium to stress. Coronary adenosine receptors (AdR) are not normally active but cause vasodilation during myocardial ischemia. This study examined the myocardial energetic response to inhibition of KATP and AdR in CHF. CHF (as evidenced by LVEDP>20mmHg) was produced in adult mongrel dogs (n=12) by rapid ventricular pacing for 4weeks. MBF was measured with radiolabeled microspheres during baseline (BL), AdR blockade with 8-phenyltheophylline (8-PT; 5mg/kg iv), and KATP blockade with glibenclamide (GLB; 20μg/kg/min ic). High energy phosphates were examined with (31)P magnetic resonance spectroscopy (MRS) while myocardial oxygenation was assessed from the deoxymyoglobin signal (Mb-δ) using (1)H MRS. During basal conditions the phosphocreatine (PCr)/ATP ratio (1.73±0.15) was significantly lower than in previously studied normal dogs (2.42±0.11) although Mb-δ was undetectable. 8-PT caused ≈21% increase in MBF with no change in PCr/ATP. GLB caused a 33±0.1% decrease in MBF with a decrease in PCr/ATP from 1.65±0.17 to 1.11±0.11 (p<0.0001). GLB did not change the pseudo-first-order rate constant of ATP production via CK (kf), but the ATP production rate via CK was reduced by 35±0.08%; this was accompanied by an increase in Pi/PCr and appearance of a Mb-δ signal indicating tissue hypoxia. Thus, in the failing heart the balance between myocardial ATP demands and oxygen delivery is critically dependent on functioning KATP channels. PMID:26854629

  19. MRI measurements of left ventricular systolic wall thickening compared to regional myocardial perfusion as determined by 201Tl SPECT in patients with coronary artery disease.

    PubMed

    Kleinhans, E; Altehoefer, C; Arnold, C; Buell, U; vom Dahl, J; Uebis, R

    1991-04-01

    Magnetic resonance imaging (MRI) of the left ventricle (LV) is an excellent method of measuring systolic wall thickening (SWT). The aim of the present study was (a) to describe a new approach for measurement of SWT and (b) to define the relationship between SWT and regional myocardial perfusion as determined by 201Tl SPECT. 79 patients -51 with and 28 without history of earlier myocardial infarction - underwent SPECT and, within the next two weeks. MRI. End-diastolic and end-systolic spin echo images were obtained by a reduced permutation technique. For MRI measurements, only long-axis sections through the LV in the equatorial plane were used. Slice orientation was selected according to the findings of SPECT, imaging the infarcted wall segment by single or double angulation. At 7 equidistant points around the LV wall SWT was measured and compared with the corresponding regional myocardial uptake values from SPECT in percent of maximal perfusion. Wall thickness of the anterior wall was normal. Because the majority of myocardial infarctions were posterior-inferior (55%), thickness of the posterior wall was markedly decreased. A close relationship of perfusion to SWT was found. Higher perfusion areas (greater than 50% of maximal TI uptake) corresponded with normal SWT (greater than 3.0 mm), a marked decrease of SWT (less than 1 mm) was found in areas with perfusion deficits (less than 40%). Thus, a 201TI uptake value at rest of 41-50% of the respective myocardial maximum acts as a threshold by discriminating normal from severely reduced SWT. PMID:2047242

  20. Septal and Anterior Reverse Mismatch of Myocardial Perfusion and Metabolism in Patients With Coronary Artery Disease and Left Bundle Branch Block

    PubMed Central

    Wang, Jian-Guang; Fang, Wei; Yang, Min-Fu; Tian, Yue-Qin; Zhang, Xiao-Li; Shen, Rui; Sun, Xiao-Xin; Guo, Feng; Wang, Dao-Yu; He, Zuo-Xiang

    2015-01-01

    Abstract The effects of left bundle branch block (LBBB) on left ventricular myocardial metabolism have not been well investigated. This study evaluated these effects in patients with coronary artery disease (CAD). Sixty-five CAD patients with complete LBBB (mean age, 61.8 ± 9.7 years) and 65 without LBBB (mean age, 59.9 ± 8.4 years) underwent single photon emission computed tomography, positron emission tomography, and contrast coronary angiography. The relationship between myocardial perfusion and metabolism and reverse mismatch score, and that between QRS length and reverse mismatch score and wall motion score were evaluated. The incidence of left ventricular septum and anterior wall reverse mismatching between the two groups was significantly different (P < 0.001 and P = 0.002, respectively). The incidences of normal myocardial perfusion and metabolism in the left ventricular lateral and inferior walls were also significantly different between the two groups (P < 0.001 and P < 0.001, respectively). The incidence of septal reverse mismatching in patients with mild to moderate perfusion was significantly higher among those with LBBB than among those without LBBB (P < 0.001). In CAD patients with LBBB, septal reverse mismatching was significantly more common among those with mild to moderate perfusion than among those with severe perfusion defects (P = 0.002). The correlation between the septal reverse mismatch score and QRS length was significant (P = 0.026). In patients with CAD and LBBB, septal and anterior reverse mismatching of myocardial perfusion and metabolism was frequently present; the septal reverse mismatch score negatively correlated with the QRS interval. PMID:25997045

  1. Failure of perchlorate to inhibit Tc-99m isonitrile binding by the thyroid during myocardial perfusion studies.

    PubMed

    Civelek, A C; Durski, K; Shafique, I; Matsumura, K; Sostre, S; Wagner, H N; Ladenson, P W

    1991-05-01

    The thyroid gland receives an average radiation dose of 3 rads during two Tc-99m isonitrile (MIBI) myocardial perfusion studies, if 20 mCi is administered both at rest and at peak exercise. In patients with coronary artery disease, multiple myocardial perfusion studies may be required, resulting in a high level of thyroid radiation. We attempted to reduce this radiation exposure by blocking thyroidal Tc-99m MIBI uptake with oral potassium perchlorate (KCIO4). Fourteen normal subjects received 0.6g to 0.8g KCIO4 20-25 minutes before tracer injection. Subjects who received KCIO4 at rest (n = 11) did not receive KCIO4 at their stress study, and vice versa (n = 3). Thyroid uptake values were obtained with a thyroid probe 20 minutes after injection for both rest and stress studies and were corrected for saturation effects. There was no difference between fractional thyroid uptake values with and without preceding perchlorate administration: 1.9 +/- 0.5% and 1.8 +/- 0.3% (mean +/- SD), respectively. Failure to block Tc-99m MIBI uptake after intravenous (IV) injection is probably due to high thyroidal blood flow and nonspecific tracer accumulation. The concentration of this radioisotope in adjacent muscles also contributes to the high thyroid radiation dose. In summary, administration of KCIO4 before Tc-99m MIBI studies does not reduce the thyroidal radiation dose or uptake of this tracer, suggesting that thyroidal uptake of this tracer is not mediated by the iodine trapping mechanism. PMID:1647286

  2. Assessment of single vessel coronary artery disease: results of exercise electrocardiography, thallium-201 myocardial perfusion imaging and radionuclide angiography

    SciTech Connect

    Port, S.C.; Oshima, M.; Ray, G.; McNamee, P.; Schmidt, D.H.

    1985-07-01

    The sensitivity of the commonly used stress tests for the diagnosis of coronary artery disease was analyzed in 46 patients with significant occlusion (greater than or equal to 70% luminal diameter obstruction) of only one major coronary artery and no prior myocardial infarction. In all patients, thallium-201 perfusion imaging (both planar and seven-pinhole tomographic) and 12 lead electrocardiography were performed during the same graded treadmill exercise test and radionuclide angiography was performed during upright bicycle exercise. Exercise rate-pressure (double) product was 22,307 +/- 6,750 on the treadmill compared with 22,995 +/- 5,622 on the bicycle (p = NS). Exercise electrocardiograms were unequivocally abnormal in 24 patients (52%). Qualitative planar thallium images were abnormal in 42 patients (91%). Quantitative analysis of the tomographic thallium images were abnormal in 41 patients (89%). An exercise ejection fraction of less than 0.56 or a new wall motion abnormality was seen in 30 patients (65%). Results were similar for the right (n = 11) and left anterior descending (n = 28) coronary arteries while all tests but the planar thallium imaging showed a lower sensitivity for isolated circumflex artery disease (n = 7). The specificity of the tests was 72, 83, 89 and 72% for electrocardiography, planar thallium imaging, tomographic thallium imaging and radionuclide angiography, respectively. The results suggest that exercise thallium-201 perfusion imaging is the most sensitive noninvasive stress test for the diagnosis of single vessel coronary artery disease.

  3. Non-Ischemic Perfusion Defects due to Delayed Arrival of Contrast Material on Stress Perfusion Cardiac Magnetic Resonance Imaging after Coronary Artery Bypass Graft Surgery

    PubMed Central

    Kim, Yeo Koon; Park, Sang Joon; Cheon, Gi Jeong; Lee, Whal; Chung, Jin Wook; Park, Jae Hyung

    2014-01-01

    Herein we report about the adenosine stress perfusion MR imaging findings of a 50-year-old man who exhibited two different perfusion defects resulting from two different mechanisms after a coronary artery bypass surgery. An invasive coronary angiography confirmed that one perfusion defect at the mid-anterior wall resulted from an ischemia due to graft stenosis. However, no stenosis was detected on the graft responsible for the mid-inferior wall showing the other perfusion defect. It was assumed that the perfusion defect at the mid-inferior wall resulted from delayed perfusion owing to the long pathway of the bypass graft. The semiquantitative analysis of corrected signal-time curves supported our speculation, demonstrating that the rest-to-stress ratio index of the maximal slope of the myocardial territory in question was similar to those of normal myocardium, whereas that of myocardium with the stenotic graft showed a typical ischemic pattern. A delayed perfusion during long graft pathway in a post-bypass graft patient can mimick a true perfusion defect on myocardial stress MR imaging. Radiologists should be aware of this knowledge to avoid misinterpretation of graft and myocardial status in post bypass surgery patients. PMID:24644408

  4. The role of gated myocardial perfusion scintigraphy (GMPS) in myocarditis: a case report and review of the literature.

    PubMed

    Javadi, Hamid; Jallalat, Sara; Pourbehi, Gholamreza; Semnani, Shahriar; Mogharrabi, Mehdi; Nabipour, Iraj; Ravanbod, Mohammadreza; Amini, Abdullatif; Assadi, Majid

    2011-01-01

    Acute myocarditis is one of the most challenging diagnoses and treatments in cardiology. The acute viral myocarditis diagnosis is usually based on high suspicion, history taking, and physical examination. Likewise, the use of chest radiography, electrocardiography (ECG), and echocardiography is helpful in making a final diagnosis, but all are non-specific. In addition, in imaging query, magnetic resonance imaging (MRI) depicts some degree of cardiac inflammation in the course of myocarditis. Myocardial perfusion imaging (MPI) has also been shown to be useful in diagnosis, and this noninvasive technique diminishes the need for myocardial biopsy. The current study presents the diagnostic and prognostic role of MPI in a 25-year-old patientwith suspected myocarditis. The patient underwent gated-technetium- 99m-lablled, methoxyisobutyl isonitrile, single photon emission computed tomography (Gated 99mTc-MIBI SPECT) that showed nonheterogeneous absorption with remarkable decreased radiotracer uptake in the myocardium in both stress and rest phases. In addition, the gated mode demonstrated decreased wall motion and thickening of the myocardium with a sum motion score (SMS) of 28, a sum thickening score (STS) of 15, and a measured LVEF of 34%. The study concludes that 99mTC-MIBI SPECT imaging is a useful modality in the preparation of supplementary diagnostic and prognostic information in viral myocarditis. PMID:22219153

  5. In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

    PubMed Central

    van Deel, Elza; Ridwan, Yanto; van Vliet, J. Nicole; Belenkov, Sasha; Essers, Jeroen

    2016-01-01

    The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD). PMID:26967592

  6. In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography.

    PubMed

    van Deel, Elza; Ridwan, Yanto; van Vliet, J Nicole; Belenkov, Sasha; Essers, Jeroen

    2016-01-01

    The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD). PMID:26967592

  7. Surgical treatment of acute myocardial ischaemia related to coronary angioplasty with special reference to use of perfusion balloon catheter and long-term outcome.

    PubMed

    Heikkinen, L; Virtanen, K; Heikkila, J; Verkkala, K; Salo, J; Jarvinen, A

    1997-04-01

    Twenty of 569 consecutive patients (3.5%) undergoing percutaneous transluminal coronary angioplasty required emergency coronary artery bypass grafting for acute closure of the dilated vessel. In seven patients an intracoronary autoperfusion balloon catheter was inserted to ensure antegrade blood flow across the injured zone of the coronary artery. The time needed for completion of the bypass grafts ranged from 100 to 399 minutes (mean 180 minutes). An average of 1.9 coronary artery bypasses was inserted. In total, 11 of the 20 patients (55%) developed new Q waves and had elevated CK-MB levels. However, the myocardial infarction rate was only 14% in those with a perfusion balloon catheter as against 77% in those without one. The insertion of a ball-out catheter permitted greater utilization of the internal mammary artery as a bypass graft. Angiographic follow-up was conducted after a mean of 28 months (19 patients). The patency rate of the bypass grafts placed in the emergency setting was relatively good (91%). Thallium tomography revealed a scar of variable size in all 17 patients studied and a reversible exercise perfusion defect requiring coronary reangioplasty in three patients. In conclusion, the insertion of a perfusion balloon catheter after abrupt coronary occlusion during coronary angioplasty solved the problems of acute myocardial ischemia and markedly lowered the definite myocardial infarction rate. This technique ensures favourable haemodynamic conditions for emergency myocardial revascularization. PMID:9201117

  8. Dose reduction assessment in dynamic CT myocardial perfusion imaging in a porcine balloon-induced-ischemia model

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2014-03-01

    We investigated the use of an advanced hybrid iterative reconstruction (IR) technique (iDose4, Philips Health- care) for low dose dynamic myocardial CT perfusion (CTP) imaging. A porcine model was created to mimic coronary stenosis through partial occlusion of the left anterior descending (LAD) artery with a balloon catheter. The severity of LAD occlusion was adjusted with FFR measurements. Dynamic CT images were acquired at end-systole (45% R-R) using a multi-detector CT (MDCT) scanner. Various corrections were applied to the acquired scans to reduce motion and imaging artifacts. Absolute myocardial blood flow (MBF) was computed with a deconvolution-based approach using singular value decomposition (SVD). We compared a high and a low dose radiation protocol corresponding to two different tube-voltage/tube-current combinations (80kV p/100mAs and 120kV p/150mAs). The corresponding radiation doses for these protocols are 7.8mSv and 34.3mSV , respectively. The images were reconstructed using conventional FBP and three noise-reduction strengths of the IR method, iDose. Flow contrast-to-noise ratio, CNRf, as obtained from MBF maps, was used to quantitatively evaluate the effect of reconstruction on contrast between normal and ischemic myocardial tissue. Preliminary results showed that the use of iDose to reconstruct low dose images provide better or comparable CNRf to that of high dose images reconstructed with FBP, suggesting significant dose savings. CNRf was improved with the three used levels of iDose compared to FBP for both protocols. When using the entire 4D dynamic sequence for MBF computation, a 77% dose reduction was achieved, while considering only half the scans (i.e., every other heart cycle) allowed even further dose reduction while maintaining relatively higher CNRf.

  9. Improved First Pass Spiral Myocardial Perfusion Imaging with Variable Density Trajectories

    PubMed Central

    Salerno, Michael; Sica, Christopher; Kramer, Christopher M.; Meyer, Craig H.

    2013-01-01

    Purpose To develop and evaluate variable-density (VD) spiral first-pass perfusion pulse sequences for improved efficiency and off-resonance performance and to demonstrate the utility of an apodizing density compensation function (DCF) to improve SNR and reduce dark-rim artifact caused by cardiac motion and Gibbs Ringing. Methods Three variable density spiral trajectories were designed, simulated, and evaluated in 18 normal subjects, and in 8 patients with cardiac pathology on a 1.5T scanner. Results By utilizing a density compensation function (DCF) which intentionally apodizes the k-space data, the side-lobe amplitude of the theoretical PSF is reduced by 68%, with only a 13% increase in the FWHM of the main-lobe as compared to the same data corrected with a conventional VD DCF, and has an 8% higher resolution than a uniform density spiral with the same number of interleaves and readout duration. Furthermore, this strategy results in a greater than 60% increase in measured SNR as compared to the same VD spiral data corrected with a conventional DCF (p<0.01). Perfusion defects could be clearly visualized with minimal off-resonance and dark-rim artifacts. Conclusion VD spiral pulse sequences using an apodized DCF produce high-quality first-pass perfusion images with minimal dark-rim and off-resonance artifacts, high SNR and CNR and good delineation of resting perfusion abnormalities. PMID:23280884

  10. Comparative value of maximal treadmill testing, exercise thallium myocardial perfusion scintigraphy and exercise radionuclide ventriculography for distinguishing high- and low-risk patients soon after acute myocardial infarction

    SciTech Connect

    Hung, J.; Goris, M.L.; Nash, E.; Kraemer, H.C.; DeBusk, R.F.; Berger, W.E.; Lew, H.

    1984-05-01

    The prognostic value of symptom-limited treadmill exercise electrocardiography, exercise thallium myocardial perfusion scintigraphy and rest and exercise radionuclide ventriculography was compared in 117 men, aged 54 +/- 9 years, tested 3 weeks after a clinically uncomplicated acute myocardial infarction (MI). During a mean follow-up period of 11.6 months, 8 men experienced ''hard'' medical events (cardiac death, nonfatal ventricular fibrillation or recurrent MI) and 14 were hospitalized for unstable angina pectoris, congestive heart failure or coronary bypass surgery (total of 22 combined events). By multivariate analysis (Cox proportional hazards model), peak treadmill work load and the change in left ventricular ejection fraction (EF) during exercise were significant (p less than 0.01) predictors of hard medical events; these 2 risk factors and recurrent ischemic chest pain in the coronary care unit were also significantly predictive (p less than 0.001) for combined events. A peak treadmill work load of 4 METs or less or a decrease in EF of 5% or more below the value at rest during submaximal effort distinguished 22 high-risk patients (20% of the study population) from 89 low-risk patients. The rate of hard medical events within 12 months was 23% (5 of 22 patients), vs 2% (2 of 89 patients) in the high- and low-risk patient subsets, respectively (p less than 0.001). Thus, in patients who underwent evaluation 3 weeks after a clinically uncomplicated MI, exercise radionuclide ventriculography contributed independent prognostic information to that provided by symptom-limited treadmill testing and was superior to exercise thallium scintigraphy for this purpose.

  11. Thrombolytic therapy for myocardial infarction: Assessment of efficacy by myocardial perfusion imaging with technetium-99m sestamibi

    SciTech Connect

    Wackers, F.J. )

    1990-10-16

    Technetium-99m (Tc-99m) sestamibi has been used to evaluate the efficacy of thrombolytic therapy. Improved image quality due to the higher photon energy of Tc-99m and the increased allowable doses of this radiopharmaceutical along with its lack of redistribution makes Tc-99m sestamibi an acceptable imaging agent for such studies. This imaging agent was used for serial quantitative planar and tomographic imaging to assess the initial risk area of infarction, its change over time and the relation to infarct-related artery patency in patients with a first acute myocardial infarction. Twenty-three of 30 patients were treated with recombinant tissue-type plasminogen activator (rt-PA) within 4 hours after onset of acute chest pain. Seven patients were treated in the conventional manner and did not receive thrombolytic therapy. The initial area at risk varied greatly both in patients treated with rt-PA and in those who received conventional therapy. Patients with successful thrombolysis and patient infarct arteries had a significantly greater reduction of Tc-99m sestamibi defect size than patients who had persistent coronary occlusion. Serial imaging with Tc-99m sestamibi could find important application in future clinical research evaluating the efficacy of new thrombolytic agents. Direct measurements of the amount of hypoperfused myocardium before and after thrombolysis could provide rapid and unequivocal results using fewer patients and avoiding the use of mortality as an end point. This approach has not yet been widely tested in the clinical arena.

  12. Visualization of hypertrophied papillary muscle mimicking left ventricular mass on gated blood pool and T1-201 myocardial perfusion imaging

    SciTech Connect

    Bunko, H.; Nakajima, K.; Tonami, N.; Asanoi, H.; Hisada, K.

    1981-12-01

    A sixty-year old man with acute myocardial infarction was incidentally found to have a hypertrophied anterolateral papillary muscle (ALPPM) of the left ventricle on gated blood pool (GBP) and T1-201 myocardial perfusion images. Hypertrophy of the ALPPM was visualized as a movable defect in the lateral basal area on GBP imaging throughout the cardiac cycle and on the TI-201 study as a radionuclide accumulating structure, consistent with the defect in the GBP. A combination of these findings may suggest the presence of a hypertrophied papillary muscle of the left ventricle.

  13. Motion correction for improving the accuracy of dual-energy myocardial perfusion CT imaging

    NASA Astrophysics Data System (ADS)

    Pack, Jed D.; Yin, Zhye; Xiong, Guanglei; Mittal, Priya; Dunham, Simon; Elmore, Kimberly; Edic, Peter M.; Min, James K.

    2016-03-01

    Coronary Artery Disease (CAD) is the leading cause of death globally [1]. Modern cardiac computed tomography angiography (CCTA) is highly effective at identifying and assessing coronary blockages associated with CAD. The diagnostic value of this anatomical information can be substantially increased in combination with a non-invasive, low-dose, correlative, quantitative measure of blood supply to the myocardium. While CT perfusion has shown promise of providing such indications of ischemia, artifacts due to motion, beam hardening, and other factors confound clinical findings and can limit quantitative accuracy. In this paper, we investigate the impact of applying a novel motion correction algorithm to correct for motion in the myocardium. This motion compensation algorithm (originally designed to correct for the motion of the coronary arteries in order to improve CCTA images) has been shown to provide substantial improvements in both overall image quality and diagnostic accuracy of CCTA. We have adapted this technique for application beyond the coronary arteries and present an assessment of its impact on image quality and quantitative accuracy within the context of dual-energy CT perfusion imaging. We conclude that motion correction is a promising technique that can help foster the routine clinical use of dual-energy CT perfusion. When combined, the anatomical information of CCTA and the hemodynamic information from dual-energy CT perfusion should facilitate better clinical decisions about which patients would benefit from treatments such as stent placement, drug therapy, or surgery and help other patients avoid the risks and costs associated with unnecessary, invasive, diagnostic coronary angiography procedures.

  14. Improved myocardial perfusion after transmyocardial laser revascularization in a patient with microvascular coronary artery disease

    PubMed Central

    Mayeda, Guy S; Burstein, Steven; Gheissari, Ali; French, William J; Thomas, Joseph; Kloner, Robert A

    2014-01-01

    We report the case of a 59-year-old woman who presented with symptoms of angina that was refractory to medical management. Although her cardiac catheterization revealed microvascular coronary artery disease, her symptoms were refractory to optimal medical management that included ranolazine. After undergoing transmyocardial revascularization, her myocardial ischemia completely resolved and her symptoms dramatically improved. This case suggests that combination of ranolazine and transmyocardial revascularization can be applied to patients with microvascular coronary artery disease. PMID:27489642

  15. Myocardial kinetics of thallium-201 after stress in normal and perfusion-reduced canine myocardium

    SciTech Connect

    Okada, R.D.

    1985-12-01

    Despite the emerging use of quantitative computer programs for assessing myocardial thallium uptake and clearance after exercise, little is known about the kinetics of thallium after exercise stress. Accordingly, 11 mongrel dogs with experimental left anterior descending coronary stenoses were given thallium during norepinephrine infusion to simulate exercise. The infusion was discontinued and thallium activity was monitored regionally using miniature radiation detectors for 3 hours. Heart rate, arterial pressure and double product all increased significantly during norepinephrine infusion. The mean fractional myocardial thallium clearance was lower (0.47 +/- 0.03 (+/- standard error of the mean)) for the stenosis zone than for the no-stenosis zone (0.57 +/- 0.03) (p less than 0.0001). The stress blood flow ratio (stenosis/no-stenosis zone = 0.27 +/- 0.06) was significantly lower than the final thallium activity ratio (0.68 +/- 0.07) (p less than 0.001), consistent with thallium redistribution occurring over the 3-hour period. Myocardial thallium activity in the stenosis zone peaked in a mean of 2.2 minutes, then washed out biexponentially with a final decay constant of 0.0035 +/- 0.0005 min-1. Myocardial thallium activity in the no-stenosis zone peaked within 1 minute in all dogs, then washed out biexponentially, with a final decay constant of 0.0043 +/- 0.0003 (p less than 0.001 compared with stenosis zone). In conclusion, fractional clearance of thallium can differentiate myocardium distal to a coronary artery stenosis from that supplied by a normal coronary vessel.

  16. Assessment myocardial perfusion and contraction by Karhunen-Loeve transform on scintigraphic images.

    PubMed

    Blagosklonov, Oleg; Comas, Laurent; Berthout, Pascal; Sabbah, Remy; Verdenet, Josette; Cardot, Jean-Claude; Baud, Michel

    2006-01-01

    Theory and previous studies showed that KLT (an application of principal component transform for imaging) can be use for analysis of cardiac function. This paper presents the results of our studies concerning the applications of KLT for images smoothing, quantification of myocardial contraction, and improvement of inter-observer reproducibility in cardiac imaging. The paper also describes the use of 4D cardiac phantom to quantify Karhunen-Loeve images. PMID:17946716

  17. Middle age aggravates myocardial ischemia through surprising upholding of complex II activity, oxidative stress, and reduced coronary perfusion.

    PubMed

    Mourmoura, Evangelia; Leguen, Marie; Dubouchaud, Hervé; Couturier, Karine; Vitiello, Damien; Lafond, Jean-Luc; Richardson, Melanie; Leverve, Xavier; Demaison, Luc

    2011-09-01

    Aging compromises restoration of the cardiac mechanical function during reperfusion. We hypothesized that this was due to an ampler release of mitochondrial reactive oxygen species (ROS). This study aimed at characterising ex vivo the mitochondrial ROS release during reperfusion in isolated perfused hearts of middle-aged rats. Causes and consequences on myocardial function of the observed changes were then evaluated. The hearts of rats aged 10- or 52-week old were subjected to global ischemia followed by reperfusion. Mechanical function was monitored throughout the entire procedure. Activities of the respiratory chain complexes and the ratio of aconitase to fumarase activities were determined before ischemia and at the end of reperfusion. H(2)O(2) release was also evaluated in isolated mitochondria. During ischemia, middle-aged hearts displayed a delayed contracture, suggesting a maintained ATP production but also an increased metabolic proton production. Restoration of the mechanical function during reperfusion was however reduced in the middle-aged hearts, due to lower recovery of the coronary flow associated with higher mitochondrial oxidative stress indicated by the aconitase to fumarase ratio in the cardiac tissues. Surprisingly, activity of the respiratory chain complex II was better maintained in the hearts of middle-aged animals, probably because of an enhanced preservation of its membrane lipid environment. This can explain the higher mitochondrial oxidative stress observed in these conditions, since cardiac mitochondria produce much more H(2)O(2) when they oxidize FADH(2)-linked substrates than when they use NADH-linked substrates. In conclusion, the lower restoration of the cardiac mechanical activity during reperfusion in the middle-aged hearts was due to an impaired recovery of the coronary flow and an insufficient oxygen supply. The deterioration of the coronary perfusion was explained by an increased mitochondrial ROS release related to the

  18. Comparison of 180° and 360° Arc Data Acquisition to Measure Scintigraphic Parameters from Gated Single Photon Emission Computed Tomography Myocardial Perfusion Imaging: Is There Any Difference?

    PubMed Central

    Javadi, Hamid; Mahmoud-Pashazadeh, Ali; Mogharrabi, Mehdi; Iranpour, Darioush; Amini, Abdollatif; Pourbehi, Mohammadreza; Akbarzadeh, Mehdi; Nabipour, Iraj; Assadi, Majid

    2016-01-01

    Objective: The aim of the current study was to compare 180° and 360° data collection modes to measure end diastolic volume (EDV), end systolic volume (ESV) and ejection fraction (EF) values of the cardiac system by gated myocardial perfusion tomography. Methods: Thirty-three patients underwent gated myocardial perfusion tomography. Single photon emission computed tomography data of patients’ heart were acquired by 180°, 45° left posterior oblique to 45° right anterior oblique, and 360° to obtain EDV, ESV, EF and cardiac volume changes (V1, V2, V3, V4, V5, V6, V7 and V8) throughout each cardiac cycle. Results: Results of the current study indicated that there were no significant differences between 180° and 360° angular sampling in terms of measuring EDV, ESV and EF in myocardial perfusion imaging. Cardiac volume change patterns during a cardiac cycle were also similar in 360° and 180° scans. We also observed that there was no difference in EDV, ESV and EF values between the group with stress induced by exercise and the group with stress imposed by dipyridamole. Conclusion: As there is no difference between 180°and 360° cardiac scanning in terms of EDV, ESV and EF, half-orbit scan is recommended to study these cardiac system parameters because it offers more comfort to patients and a shorter scanning time. PMID:27299285

  19. A randomized, placebo-controlled trial of late Na current inhibition (ranolazine) in coronary microvascular dysfunction (CMD): impact on angina and myocardial perfusion reserve

    PubMed Central

    Bairey Merz, C. Noel; Handberg, Eileen M.; Shufelt, Chrisandra L.; Mehta, Puja K.; Minissian, Margo B.; Wei, Janet; Thomson, Louise E.J.; Berman, Daniel S.; Shaw, Leslee J.; Petersen, John W.; Brown, Garrett H.; Anderson, R. David; Shuster, Jonathan J.; Cook-Wiens, Galen; Rogatko, André; Pepine, Carl J.

    2016-01-01

    Aims The mechanistic basis of the symptoms and signs of myocardial ischaemia in patients without obstructive coronary artery disease (CAD) and evidence of coronary microvascular dysfunction (CMD) is unclear. The aim of this study was to mechanistically test short-term late sodium current inhibition (ranolazine) in such subjects on angina, myocardial perfusion reserve index, and diastolic filling. Materials and results Randomized, double-blind, placebo-controlled, crossover, mechanistic trial in subjects with evidence of CMD [invasive coronary reactivity testing or non-invasive cardiac magnetic resonance imaging myocardial perfusion reserve index (MPRI)]. Short-term oral ranolazine 500–1000 mg twice daily for 2 weeks vs. placebo. Angina measured by Seattle Angina Questionnaire (SAQ) and SAQ-7 (co-primaries), diary angina (secondary), stress MPRI, diastolic filling, quality of life (QoL). Of 128 (96% women) subjects, no treatment differences in the outcomes were observed. Peak heart rate was lower during pharmacological stress during ranolazine (−3.55 b.p.m., P < 0.001). The change in SAQ-7 directly correlated with the change in MPRI (correlation 0.25, P = 0.005). The change in MPRI predicted the change in SAQ QoL, adjusted for body mass index (BMI), prior myocardial infarction, and site (P = 0.0032). Low coronary flow reserve (CFR <2.5) subjects improved MPRI (P < 0.0137), SAQ angina frequency (P = 0.027), and SAQ-7 (P = 0.041). Conclusions In this mechanistic trial among symptomatic subjects, no obstructive CAD, short-term late sodium current inhibition was not generally effective for SAQ angina. Angina and myocardial perfusion reserve changes were related, supporting the notion that strategies to improve ischaemia should be tested in these subjects. Trial registration clinicaltrials.gov Identifier: NCT01342029. PMID:26614823

  20. Heterogeneous fate of perfusion and contraction after anterior wall acute myocardial infarction and effects on left ventricular remodeling.

    PubMed

    Marcassa, C; Galli, M; Bolli, R; Temporelli, P L; Campini, R; Giannuzzi, P

    1998-12-15

    After acute myocardial infarction, patency of infarct vessel and extent of left venticular (LV) dysfunction are major determinants of ventricular remodeling. Spontaneous, delayed reperfusion in the infarct zone occurs in a sizeable number of patients well after the subacute phase. The aim of this study was to determine the relation between the occurrence of this spontaneous, delayed reperfusion and LV remodeling. In 84 patients, resting LV volumes, topography, regional function, and perfusion were quantitatively evaluated by 2-dimensional echocardiography and sestamibi tomography 5 weeks (study 1) and 7 months (study 2) after anterior Q-wave infarction. At study 2, LV end-diastolic volume increased by > 15% in 17 patients (20%, LV remodeling); they had already had at study 1 significantly larger LV volumes, more severe hypoperfusion and wall motion abnormalities, and greater regional dilation than patients with stable LV volumes. Delayed reperfusion occurred in 8 of 17 patients with and in 42 of 67 patients without LV remodeling (47% vs 63%; p=NS). At study 2, LV regional dilation and end-diastolic volumes were stable in patients with, but increased in patients without, spontaneous reperfusion (from 25+/-24% to 29+/-26% at study 2 [p<0.05] and from 65+/-14 to 68+/-18 ml/m2 [p <0.05]). At multivariate analysis, however, regional ventricular dilation at study 1 was the sole predictor of further LV remodeling. Thus, after acute myocardial infarction, spontaneous reperfusion occurring after 5 weeks plays only a minor role in influencing LV remodeling. Benefits from delayed reperfusion seem limited to patients with preserved LV volumes; patients with an enlarged left ventricle 5 weeks after acute infarction are prone to further LV remodeling, irrespective of delayed reperfusion. PMID:9874047

  1. Myocardial metabolism, perfusion, wall motion and electrical activity in Duchenne muscular dystrophy

    SciTech Connect

    Perloff, J.K.; Henze, E.; Schelbert, H.R.

    1982-01-01

    The cardiomyopathy of Duchenne's muscular dystrophy originates in the posterobasal left ventricle and extends chiefly to the contiguous lateral wall. Ultrastructural abnormalities in these regions precede connective tissue replacement. We postulated that a metabolic fault coincided with or antedated the subcellular abnormality. Accordingly, regional left ventricular metabolism, perfusion and wall motion were studied using positron computed tomography and metabolic isotopes supplemented by thallium perfusion scans, equilibrium radionuclide angiography and M-mode and two-dimensional echocardiography. To complete the assessment, electrocardiograms, vectorcardiograms, 24 hour taped electrocardiograms and chest x-rays were analyzed. Positron computed tomography utilizing F-18 2-fluoro 2-deoxyglucose (FDG) provided the first conclusive evidence supporting the hypothesis of a premorphologic regional metabolic fault. Thus, cardiac involvement in duchenne dystrophy emerges as a unique form of heart disease, genetically targeting specific regions of ventricular myocardium for initial metabolic and subcellular changes. Reported ultrastructural abnormalities of the impulse and conduction systems provide, at least in part, a basis for the clinically observed sinus node, intraatrial, internodal, AV nodal and infranodal disorders.

  2. Incremental Diagnostic Performance of Combined Parameters in the Detection of Severe Coronary Artery Disease Using Exercise Gated Myocardial Perfusion Imaging

    PubMed Central

    Liu, Chia-Ju; Wu, Yen-Wen; Ko, Kuan-Yin; Chen, Yi-Chieh; Cheng, Mei-Fang; Yen, Ruoh-Fang; Tzen, Kai-Yuan

    2015-01-01

    Purpose Myocardial perfusion imaging (MPI) using gated single-photon emission tomography (gSPECT) may underestimate the severity of coronary artery disease (CAD). This study aimed to evaluate the significance of combined parameters derived from gSPECT, as well as treadmill stress test parameters, in the detection of severe CAD. Methods A total of 211 consecutive patients referred for exercise MPI between June 2011 and June 2013 (who received invasive coronary angiography within six months after MPI) were retrospectively reviewed. Exercise MPI was performed with Bruce protocol and 201Tl injected at peak exercise. Gated SPECT was performed using a cadmium-zinc-telluride camera and processed by QPS/QGS software. Perfusion defect abnormalities such as sum stress score (SSS); sum difference score, algorithm-derived total perfusion deficits, transient ischemic dilatation ratios of end-diastolic volumes and end-systolic volumes, post-stress changes in ejection fraction, and lung/heart ratio (LHR) were calculated. Treadmill parameters, including ST depression (STD) at the 1st and 3rd minutes of recovery stage (1’STD and 3’STD), maximal STD corrected by heart rate increment (ST/HR), heart rate decline in 1st and 3rd minutes of recovery stage, recovery heart rate ratio (HR ratio), systolic and mean blood pressure ratios (SBP ratio and MAP ratio) during recovery phase were recorded. Diagnostic performances of these parameters were analyzed with receiver operating characteristic (ROC) analysis and logistic regression for detection of left main (≥ 50%) or 3-vessel disease (all ≥ 70% luminal stenosis) on invasive angiography. Results Among various MPI and treadmill parameters used for detection of severe CAD, SSS and ST/HR had the highest AUC (0.78, 0.73, p = NS) and best cut-off values (SSS > 6, ST/HR > 17.39 10-2mV/bpm), respectively. By univariate logistic regression, all parameters except 1’HRR, 3’HRR, SBP and MAP ratios increased the odds ratio of severe CAD

  3. Computational Fluid Dynamics Simulations of Contrast Agent Bolus Dispersion in a Coronary Bifurcation: Impact on MRI-Based Quantification of Myocardial Perfusion

    PubMed Central

    Schmidt, Regine; Graafen, Dirk; Weber, Stefan; Schreiber, Laura M.

    2013-01-01

    Contrast-enhanced first-pass magnetic resonance imaging (MRI) in combination with a tracer kinetic model, for example, MMID4, can be used to determine myocardial blood flow (MBF) and myocardial perfusion reserve (MPR). Typically, the arterial input function (AIF) required for this methodology is estimated from the left ventricle (LV). Dispersion of the contrast agent bolus might occur between the LV and the myocardial tissue. Negligence of bolus dispersion could cause an error in MBF determination. The aim of this study was to investigate the influence of bolus dispersion in a simplified coronary bifurcation geometry including one healthy and one stenotic branch on the quantification of MBF and MPR. Computational fluid dynamics (CFD) simulations were combined with MMID4. Different inlet boundary conditions describing pulsatile and constant flows for rest and hyperemia and differing outflow conditions have been investigated. In the bifurcation region, the increase of the dispersion was smaller than inside the straight vessels. A systematic underestimation of MBF values up to −16.1% for pulsatile flow and an overestimation of MPR up to 7.5% were found. It was shown that, under the conditions considered in this study, bolus dispersion can significantly influence the results of quantitative myocardial MR-perfusion measurements. PMID:23533541

  4. Comparison of personnel radiation dosimetry from myocardial perfusion scintigraphy: Technetium-99m-sestamibi versus thallium-201

    SciTech Connect

    Culver, C.M.; Dworkin, H.J. )

    1993-07-01

    The whole-body and hand radiation doses to our technical staff were retrospectively compared for three distinct 4-mo periods when either 201TI or 99mTc-sestamibi were exclusively used for stress myocardial perfusion imaging. During the initial 4-mo period when 99mTc-sestamibi replaced 201TI, the mean whole-body film badge readings increased from 100 to 450 microSv/mo (p < 0.001) for nuclear medicine technologists (n = 10) and from 240 to 560 microSv/mo (p < 0.05) for radiopharmacy technologists (n = 2). Mean TLD readings to the hands also increased, although the differences were not statistically significant for the nuclear medicine technologists. Noninvasive cardiology staff were monitored with film badges and the mean whole-body film badge reading, when 99mTc-sestamibi was the imaging agent, was 360 microSv per month. Radiation reduction methods that decreased radiation exposure to staff were utilized. The most effective included the use of a lead face shield and lead lined storage container in the noninvasive imaging area, handling spills by shielding instead of decontamination and methods to reduce time spent in close proximity to the patient.

  5. Comparison of personnel radiation dosimetry from myocardial perfusion scintigraphy: technetium-99m-sestamibi versus thallium-201.

    PubMed

    Culver, C M; Dworkin, H J

    1993-07-01

    The whole-body and hand radiation doses to our technical staff were retrospectively compared for three distinct 4-mo periods when either 201TI or 99mTc-sestamibi were exclusively used for stress myocardial perfusion imaging. During the initial 4-mo period when 99mTc-sestamibi replaced 201TI, the mean whole-body film badge readings increased from 100 to 450 microSv/mo (p < 0.001) for nuclear medicine technologists (n = 10) and from 240 to 560 microSv/mo (p < 0.05) for radiopharmacy technologists (n = 2). Mean TLD readings to the hands also increased, although the differences were not statistically significant for the nuclear medicine technologists. Noninvasive cardiology staff were monitored with film badges and the mean whole-body film badge reading, when 99mTc-sestamibi was the imaging agent, was 360 microSv per month. Radiation reduction methods that decreased radiation exposure to staff were utilized. The most effective included the use of a lead face shield and lead lined storage container in the noninvasive imaging area, handling spills by shielding instead of decontamination and methods to reduce time spent in close proximity to the patient. PMID:8315504

  6. Synthesis and Evaluation of [(18) F]-Ammonium BODIPY Dyes as Potential Positron Emission Tomography Agents for Myocardial Perfusion Imaging.

    PubMed

    Chansaenpak, Kantapat; Wang, Hui; Wang, Mengzhe; Giglio, Benjamin; Ma, Xiaofeng; Yuan, Hong; Hu, Shuo; Wu, Zhanhong; Li, Zibo

    2016-08-16

    Recently, we demonstrated the potential of a [(18) F]-trimethylammonium BODIPY dye for cardiac imaging. This is the first example of the use of the [(18) F]-ammonium BODIPY dye for positron emission tomography (PET) myocardial perfusion imaging (MPI). In this report, we extend our study to other ammonium BODIPY dyes with different nitrogen substituents. These novel ammonium BODIPY dyes were successfully prepared and radiolabeled by the SnCl4 -assisted (18) F-(19) F isotopic exchange method. The microPET results and the biodistribution data reveal that nitrogen substituent changes have a significant effect on the in vivo and pharmacological properties of the tracers. Of the novel [(18) F]-ammonium BODIPY dyes prepared in this work, the [(18) F]-dimethylethylammonium BODIPY is superior in terms of myocardium uptake and PET imaging contrast. These results support our hypothesis that the ammonium BODIPY dyes have a great potential for use as PET/optical dual-modality MPI probes. PMID:27405398

  7. Quantitative reconstruction for myocardial perfusion SPECT: an efficient approach by depth-dependent deconvolution and matrix rotation.

    PubMed

    Ye, J; Liang, Z; Harrington, D P

    1994-08-01

    An efficient reconstruction method for myocardial perfusion single-photon emission computed tomography (SPECT) has been developed which compensates simultaneously for attenuation, scatter, and resolution variation. The scattered photons in the primary-energy-window measurements are approximately removed by subtracting the weighted scatter-energy-window samples. The resolution variation is corrected by deconvolving the subtracted data with the detector-response kernel in frequency space using the depth-dependent frequency relation. The attenuated photons are compensated by recursively tracing the attenuation factors through the object-specific attenuation map. An experimental chest phantom with defects inside myocardium was used to test the method. The attenuation map of the phantom was reconstructed from transmission scans using a flat external source and a high-resolution parallel-hole collimator of a single-detector system. The detector-response kernel was approximated from measurements of a point source in air at several depths from the collimator surface. The emission data were acquired by the same detector setting. A computer simulation using similar protocols as in the experiment was performed. Both the simulation and experiment showed significant improvement in quantification with the proposed method, as compared to the conventional filtered-backprojection technique. The quantitative gain by the additional deconvolution was demonstrated. The computation time was less than 20 min on a HP/730 desktop computer for reconstruction of a 1282 x 64 array from 128 projections of 128 x 64 samples. PMID:15551566

  8. 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)

  9. Myocardial perfusion and coronary flow reserve in mammary artery and saphenous vein by-pass grafts with maximal dipyridamole vasodilation

    SciTech Connect

    Lassar, T.; Hendrix, L.; Port, S.; Ray, G.; Kamath, M.L.; Schmidt, D.H.

    1985-05-01

    This study was done to assess the functional adequacy of regional myocardial perfusion in angiographically patent internal mammary artery (IMAG) and saphenous vein (SVG) bypass grafts under conditions of maximal vasodilation. Utilizing the xenon-133 washout technique, quantitative RMP in ml/100g/min was measured at rest (R RMP), and after 0.6mg/kg of intravenous dipyridamole (DP RMP) via selective injection into coronary arteries with >75% diameter stenosis (SCA), angiographically normal vessels (NLCA), and two weeks postoperatively after IMAG or SVG. RMP and coronary flow reserve (CFR=DP RMP / R RMP) were compared between groups selected for study and the results are presented. The authors discuss that compared to SCA, there is a trend towards improved RMP under conditions of maximal vasodilatory demand in both IMAG and SVG. In part because of elevated R RMP, the CFR ratio may not always reflect this improvement, and finally, the trend towards higher DP RMP in SVG suggest that they may supply more adequate nutrient flow than IMAG during situations of peak demand.

  10. Risk stratification using gated stress myocardial perfusion imaging: comparison between patients with and without sexual dysfunction

    PubMed Central

    Tan, Yusuf Ziya; Ozdemir, Semra; Bekler, Adem; Akbas, Alpaslan; Gencer, Meryem; Celik, Fatmanur

    2016-01-01

    Sexuality is an indispensable part of life. When a problem is encountered related to this topic, the quality of life is negatively affected. Therefore, every problem related to sexuality is extremely private and important to an individual. This study aims to investigate the use of myocardial perfusion scintigraphy (MPS) for advanced assessment of patients with known or suspected coronary artery disease, cardiovascular disease, and in the intermediate risk group for SD. The study included 250 patients (150 male, 100 female, mean age 54±12.10) sent by the Cardiology Clinic to the Nuclear Medicine Clinic for MPS due to suspected cardiovascular disease (CVD). The questionnaire study was applied by two methods as face-to-face interviews or online. Data on sociodemographic characteristics and cardiovascular diseases together with risk factors for sexual activity were collected using a general information form. Patients were divided into three categories of risk depending on major risk factors for cardiovascular diseases: low, intermediate, and high risk. On comparing the risk scores between the groups, it was seen that there was a statistically clear reduction in the intermediate risk group of patients with SD according to MPS scoring. MPS is a cost-effective, reliable, and accurate non-invasive diagnostic method necessary for routine use to assess cardiovascular disease and in the intermediate risk group for SD. PMID:26755812

  11. Functional Relevance of Coronary Artery Disease by Cardiac Magnetic Resonance and Cardiac Computed Tomography: Myocardial Perfusion and Fractional Flow Reserve

    PubMed Central

    Andreini, Daniele; Bertella, Erika; Mushtaq, Saima; Guaricci, Andrea Igoren; Pepi, Mauro

    2015-01-01

    Coronary artery disease (CAD) is one of the leading causes of morbidity and mortality and it is responsible for an increasing resource burden. The identification of patients at high risk for adverse events is crucial to select those who will receive the greatest benefit from revascularization. To this aim, several non-invasive functional imaging modalities are usually used as gatekeeper to invasive coronary angiography, but the diagnostic yield of elective invasive coronary angiography remains unfortunately low. Stress myocardial perfusion imaging by cardiac magnetic resonance (stress-CMR) has emerged as an accurate technique for diagnosis and prognostic stratification of the patients with known or suspected CAD thanks to high spatial and temporal resolution, absence of ionizing radiation, and the multiparametric value including the assessment of cardiac anatomy, function, and viability. On the other side, cardiac computed tomography (CCT) has emerged as unique technique providing coronary arteries anatomy and more recently, due to the introduction of stress-CCT and noninvasive fractional flow reserve (FFR-CT), functional relevance of CAD in a single shot scan. The current review evaluates the technical aspects and clinical experience of stress-CMR and CCT in the evaluation of functional relevance of CAD discussing the strength and weakness of each approach. PMID:25692133

  12. Specificity and sensitivity of SPECT myocardial perfusion studies at the Nuclear Medicine Department of the Limassol General Hospital in Cyprus

    NASA Astrophysics Data System (ADS)

    Koumna, S.; Yiannakkaras, Ch; Avraamides, P.; Demetriadou, O.

    2011-09-01

    The aim is to determine the sensitivity and specificity of Myocardial Perfusion Imaging (MPI) performed at the Nuclear Medicine Department of the Limassol General Hospital in Cyprus. Through a retrospective analysis, patient results obtained by MPI were compared to results obtained by Invasive Angiography. We analyzed data from 96 patients that underwent both MPI and Angiography during the years 2009-2010, with a maximum time interval of ± 9 months between the two types of medical exams. For 51 patients, the indication was the detection of CAD. For 45 patients, the indication was to assess viability and/or ischemia after MI, PCI or CABG. Out of 84 patients with CAD confirmed by angiography, 80 patients resulted in abnormal MPI (sensitivity of 95% and positive predictive value of 98%). Out of 12 patients with normal coronaries, 10 patients resulted in normal MPI (specificity of 83% and negative predictive value of 71%).In conclusion, for the patients with abnormal MPI and confirmed CAD, MPI was a useful aid for further therapy management.

  13. Myocardial perfusion defect on thallium-201 imaging in patients with chronic obstructive pulmonary disease

    SciTech Connect

    Mehrotra, P.P.; Weaver, Y.J.; Higginbotham, E.A.

    1983-08-01

    Six patients with angina pectoris had reversible perfusion defects on stress and redistribution thallium imaging. Three patients had a positive electrocardiographic response to exercise. No significant coronary artery lesions were seen on coronary arteriography in any of the six patients. All had mild to moderate hypoxemia at rest and physiologic evidence of chronic obstructive pulmonary disease as defined by the decrease in the ratio of forced expiratory volume at 1 second to forced vital capacity (FEV1/FVC X 100) or decrease in the forced midexpiratory flow rate (FEF25-75), or both. None had clinical findings suggestive of any of the reported causes of positive thallium scans in patients with normal coronary arteriograms. Cellular dysfunction produced by hypoxemia affecting the uptake of thallium seems to be the most likely mechanism of this abnormality.

  14. Story of Rubidium-82 and Advantages for Myocardial Perfusion PET Imaging.

    PubMed

    Chatal, Jean-François; Rouzet, François; Haddad, Ferid; Bourdeau, Cécile; Mathieu, Cédric; Le Guludec, Dominique

    2015-01-01

    Rubidium-82 has a long story, starting in 1954. After preclinical studies in dogs showing that myocardial uptake of this radionuclide was directly proportional to myocardial blood flow (MBF), clinical studies were performed in the 80s leading to an approval in the USA in 1989. From that time, thousands of patients have been tested and their results have been reported in three meta-analyses. Pooled patient-based sensitivity and specificity were, respectively, 0.91 and 0.90. By comparison with (99m)Tc-SPECT, (82)Rb PET had a much better diagnostic accuracy, especially in obese patients with body mass index ≥30 kg/m(2) (85 versus 67% with SPECT) and in women with large breasts. A great advantage of (82)Rb PET is its capacity to accurately quantify MBF. Quite importantly, it has been recently shown that coronary flow reserve is associated with adverse cardiovascular events independently of luminal angiographic severity. Moreover, coronary flow reserve is a functional parameter particularly useful in the estimate of microvascular dysfunction, such as in diabetes mellitus. Due to the very short half-life of rubidium-82, the effective dose calculated for a rest/stress test is roughly equivalent to the annual natural exposure and even less when stress-only is performed with a low activity compatible with a good image quality with the last generation 3D PET scanners. There is still some debate on the relative advantages of (82)Rb PET with regard to (99m)Tc-SPECT. For the last 10 years, great technological advances substantially improved performances of SPECT with its accuracy getting closer to this of (82)Rb/PET. Currently, the main advantages of PET are its capacity to accurately quantify MBF and to deliver a low radiation exposure. PMID:26442267

  15. Story of Rubidium-82 and Advantages for Myocardial Perfusion PET Imaging

    PubMed Central

    Chatal, Jean-François; Rouzet, François; Haddad, Ferid; Bourdeau, Cécile; Mathieu, Cédric; Le Guludec, Dominique

    2015-01-01

    Rubidium-82 has a long story, starting in 1954. After preclinical studies in dogs showing that myocardial uptake of this radionuclide was directly proportional to myocardial blood flow (MBF), clinical studies were performed in the 80s leading to an approval in the USA in 1989. From that time, thousands of patients have been tested and their results have been reported in three meta-analyses. Pooled patient-based sensitivity and specificity were, respectively, 0.91 and 0.90. By comparison with 99mTc-SPECT, 82Rb PET had a much better diagnostic accuracy, especially in obese patients with body mass index ≥30 kg/m2 (85 versus 67% with SPECT) and in women with large breasts. A great advantage of 82Rb PET is its capacity to accurately quantify MBF. Quite importantly, it has been recently shown that coronary flow reserve is associated with adverse cardiovascular events independently of luminal angiographic severity. Moreover, coronary flow reserve is a functional parameter particularly useful in the estimate of microvascular dysfunction, such as in diabetes mellitus. Due to the very short half-life of rubidium-82, the effective dose calculated for a rest/stress test is roughly equivalent to the annual natural exposure and even less when stress-only is performed with a low activity compatible with a good image quality with the last generation 3D PET scanners. There is still some debate on the relative advantages of 82Rb PET with regard to 99mTc-SPECT. For the last 10 years, great technological advances substantially improved performances of SPECT with its accuracy getting closer to this of 82Rb/PET. Currently, the main advantages of PET are its capacity to accurately quantify MBF and to deliver a low radiation exposure. PMID:26442267

  16. Migration of bone marrow-derived cells and improved perfusion after treatment with erythropoietin in a murine model of myocardial infarction

    PubMed Central

    Brunner, Stefan; Huber, Bruno C; Weinberger, Tobias; Vallaster, Marcus; Wollenweber, Tim; Gerbitz, Armin; Hacker, Marcus; Franz, Wolfgang-Michael

    2012-01-01

    Abstract Erythropoietin (EPO) was shown to have protective effects after myocardial infarction (MI) by neovascularization and antiapoptotic mechanisms. Beside direct receptor-dependent mechanisms, mobilization and homing of bone marrow-derived cells (BMCs) may play a pivotal role in this regard. In this study, we intended to track different subpopulations of BMCs and to assess serially myocardial perfusion changes in EPO-treated mice after MI. To allow tracking of BMCs, we used a chimeric mouse model. Therefore, mice (C57BL/6J) were sublethally irradiated, and bone marrow (BM) from green fluorescent protein transgenic mice was transplanted. Ten weeks later coronary artery ligation was performed to induce MI. EPO was injected for 3 days with a total dose of 5000 IU/kg. Subpopulations (CD31, c-kit, CXCR-4 and Sca-1) of EGFP+ cells were studied in peripheral blood, bone marrow and hearts by flow cytometry. Myocardial perfusion was serially investigated in vivo by pinhole single-photon emission computed tomography (SPECT) at days 6 and 30 after MI. EPO-treated animals revealed an enhanced mobilization of BMCs into peripheral blood. The numbers of these cells in BM remained unchanged. Homing of all BMCs subpopulations to the ischaemic myocardium was significantly increased in EPO-treated mice. Among the investigated subpopulations, EPO predominantly affected migration of CXCR-4+ (4.3-fold increase). Repetitively SPECT analyses revealed a reduction of perfusion defects after EPO treatment over time. Our study shows that EPO treatment after MI enhances the migration capacity of BMCs into ischaemic tissue, which may attribute to an improved perfusion and reduced size of infarction, respectively. PMID:21362129

  17. Myocardial function and perfusion in the CREST syndrome variant of progressive systemic sclerosis. Exercise radionuclide evaluation and comparison with diffuse scleroderma

    SciTech Connect

    Follansbee, W.P.; Curtiss, E.I.; Medsger, T.A. Jr.; Owens, G.R.; Steen, V.D.; Rodnan, G.P.

    1984-09-01

    Myocardial function and perfusion were evaluated in 22 patients with progressive systemic sclerosis with the CREST syndrome using exercise and radionuclide techniques, pulmonary function testing, and chest roentgenography. The results were compared with a similar study of 26 patients with progressive systemic sclerosis with diffuse scleroderma. The prevalence of thallium perfusion abnormalities was similar in the groups with CREST syndrome and diffuse scleroderma, (64 percent versus 77 percent), but the defects were significantly smaller in the CREST syndrome (p less than 0.01). Reperfusion thallium defects in the absence of extramural coronary artery disease were seen in 38 percent of patients with diffuse scleroderma. This finding was not seen in any of the patients with the CREST syndrome. In diffuse scleroderma, abnormalities of both right and left ventricular function were related to larger thallium perfusion defects. In the CREST syndrome, abnormalities of left ventricular function were minor, were seen only during exercise, and were unrelated to thallium perfusion defects. Abnormal resting right ventricular function was seen in 36 percent of the patients with the CREST syndrome and was associated with an isolated decrease in diffusing capacity of carbon monoxide. It is concluded that the cardiac manifestations of the CREST syndrome are distinct from those found in diffuse scleroderma. Unlike diffuse scleroderma, abnormalities of left ventricular function in the CREST syndrome are minor and are unrelated to abnormalities of coronary perfusion. Right ventricular dysfunction in the CREST syndrome appears to be primarily related to pulmonary vascular disease.

  18. Geometric feature-based multimodal image registration of contrast-enhanced cardiac CT with gated myocardial perfusion SPECT

    PubMed Central

    Woo, Jonghye; Slomka, Piotr J.; Dey, Damini; Cheng, Victor Y.; Hong, Byung-Woo; Ramesh, Amit; Berman, Daniel S.; Karlsberg, Ronald P.; Kuo, C.-C. Jay; Germano, Guido

    2009-01-01

    Purpose: Cardiac computed tomography (CT) and single photon emission computed tomography (SPECT) provide clinically complementary information in the diagnosis of coronary artery disease (CAD). Fused anatomical and physiological data acquired sequentially on separate scanners can be coregistered to accurately diagnose CAD in specific coronary vessels. Methods: A fully automated registration method is presented utilizing geometric features from a reliable segmentation of gated myocardial perfusion SPECT (MPS) volumes, where regions of myocardium and blood pools are extracted and used as an anatomical mask to de-emphasize the inhomogeneities of intensity distribution caused by perfusion defects and physiological variations. A multiresolution approach is employed to represent coarse-to-fine details of both volumes. The extracted voxels from each level are aligned using a similarity measure with a piecewise constant image model and minimized using a gradient descent method. The authors then perform limited nonlinear registration of gated MPS to adjust for phase differences by automatic cardiac phase matching between CT and MPS. For phase matching, they incorporate nonlinear registration using thin-plate-spline-based warping. Rigid registration has been compared with manual alignment (n=45) on 20 stress/rest MPS and coronary CTA data sets acquired from two different sites and five stress CT perfusion data sets. Phase matching was also compared to expert visual assessment. Results: As compared with manual alignment obtained from two expert observers, the mean and standard deviation of absolute registration errors of the proposed method for MPS were4.3±3.5, 3.6±2.6, and 3.6±2.1mm for translation and 2.1±3.2°, 0.3±0.8°, and 0.7±1.2° for rotation at site A and 3.8±2.7, 4.0±2.9, and 2.2±1.8mm for translation and 1.1±2.0°, 1.6±3.1°, and 1.9±3.8° for rotation at site B. The results for CT perfusion were 3.0±2.9, 3.5±2.4, and 2.8±1.0mm for translation and 3

  19. Systematic evaluation of 99mTc-tetrofosmin versus 99mTc-sestamibi to study murine myocardial perfusion in small animal SPECT/CT

    PubMed Central

    2012-01-01

    Background The “back-translation” of clinically available protocols to measure myocardial perfusion to preclinical imaging in mouse models of human disease is attractive for basic biomedical research. With respect to single-photon emission computed tomography (SPECT) approaches, clinical myocardial perfusion imaging protocols are established with different 99mTc-labeled perfusion tracers; however, studies evaluating and optimizing protocols for these tracers in high-resolution pinhole SPECT in mice are lacking. This study aims at evaluating two clinically available 99mTc-labeled myocardial perfusion tracers (99mTc-sestamibi vs. 99mTc-Tetrofosmin) in mice using four different imaging protocols. Methods Adult C57BL/6 male mice were injected with 99mTc-sestamibi (MIBI) or 99mTc-Tetrofosmin (TETRO) (4 MBq/g body weight) either intravenously through the tail vein (n = 5) or retroorbitally (n = 5) or intraperitoneally (i.p.) under anesthesia (n = 3) or i.p. in an awake state (n = 3) at rest. Immediately after injection, a multi-frame single-photon emission computed tomography/computed tomography (SPECT/CT) acquisition was initiated with six subsequent time frames of 10 min each. Reconstructed images of the different protocols were assessed and compared by visual analysis by experts and by time-activity-curves generated from regions-of-interest for various organs (normalized uptake values). Results Visually assessing overall image quality, the best image quality was found for MIBI for both intravenous injection protocols, whereas TETRO only had comparable image quality after retroorbital injections. These results were confirmed by quantitative analysis where left ventricular (LV) uptake of MIBI after tail vein injections was found significantly higher for all time points accompanied with a significantly slower washout of 16% for MIBI vs. 33% for TETRO (p = 0.009) from 10 to 60 min post injection (PI). Interestingly, LV washout from 10 to 60 min PI

  20. Role of exercise thallium-201 myocardial perfusion scintigraphy in predicting prognosis in suspected coronary artery disease

    SciTech Connect

    Koss, J.H.; Kobren, S.M.; Grunwald, A.M.; Bodenheimer, M.M.

    1987-03-01

    While exercise thallium imaging has improved sensitivity and specificity for detection of coronary artery disease (CAD), its predictive value for morbid cardiac events is unclear. Of 532 consecutive patients who underwent exercise thallium imaging, follow-up was complete in 515 (97%) after an average of 36 months (range 31 to 48). Two hundred six patients had an abnormal exercise thallium response and 309 had a normal response. Twenty morbid cardiac events occurred (13 deaths and 7 acute myocardial infarctions (AMI)). Of the 13 patients who died, 12 had abnormal thallium results. Overall, 5.8% of the patients with abnormal thallium results died, in contrast to 0.3% of patients with normal results. Of the 7 patients who had a nonfatal AMI, 3 had abnormal exercise thallium results. Moreover, similar proportions of patients (1.4% and 1.3%) with normal and abnormal exercise thallium results had nonfatal AMI. Presence or absence of pathologic Q waves and inclusion of exercise electrocardiographic results did not significantly alter the results. Thus, although a normal exercise thallium response significantly reduces the likelihood of cardiovascular death, its predictive value for nonfatal AMI is limited. Moreover, the relatively low event rate for patients with a positive exercise thallium response further limits its prognostic value.

  1. Development of 4D mathematical observer models for the task-based evaluation of gated myocardial perfusion SPECT

    NASA Astrophysics Data System (ADS)

    Lee, Taek-Soo; Frey, Eric C.; Tsui, Benjamin M. W.

    2015-04-01

    This paper presents two 4D mathematical observer models for the detection of motion defects in 4D gated medical images. Their performance was compared with results from human observers in detecting a regional motion abnormality in simulated 4D gated myocardial perfusion (MP) SPECT images. The first 4D mathematical observer model extends the conventional channelized Hotelling observer (CHO) based on a set of 2D spatial channels and the second is a proposed model that uses a set of 4D space-time channels. Simulated projection data were generated using the 4D NURBS-based cardiac-torso (NCAT) phantom with 16 gates/cardiac cycle. The activity distribution modelled uptake of 99mTc MIBI with normal perfusion and a regional wall motion defect. An analytical projector was used in the simulation and the filtered backprojection (FBP) algorithm was used in image reconstruction followed by spatial and temporal low-pass filtering with various cut-off frequencies. Then, we extracted 2D image slices from each time frame and reorganized them into a set of cine images. For the first model, we applied 2D spatial channels to the cine images and generated a set of feature vectors that were stacked for the images from different slices of the heart. The process was repeated for each of the 1,024 noise realizations, and CHO and receiver operating characteristics (ROC) analysis methodologies were applied to the ensemble of the feature vectors to compute areas under the ROC curves (AUCs). For the second model, a set of 4D space-time channels was developed and applied to the sets of cine images to produce space-time feature vectors to which the CHO methodology was applied. The AUC values of the second model showed better agreement (Spearman’s rank correlation (SRC) coefficient = 0.8) to human observer results than those from the first model (SRC coefficient = 0.4). The agreement with human observers indicates the proposed 4D mathematical observer model provides a good predictor of the

  2. Development of 4D mathematical observer models for the task-based evaluation of gated myocardial perfusion SPECT.

    PubMed

    Lee, Taek-Soo; Frey, Eric C; Tsui, Benjamin M W

    2015-04-01

    This paper presents two 4D mathematical observer models for the detection of motion defects in 4D gated medical images. Their performance was compared with results from human observers in detecting a regional motion abnormality in simulated 4D gated myocardial perfusion (MP) SPECT images. The first 4D mathematical observer model extends the conventional channelized Hotelling observer (CHO) based on a set of 2D spatial channels and the second is a proposed model that uses a set of 4D space-time channels. Simulated projection data were generated using the 4D NURBS-based cardiac-torso (NCAT) phantom with 16 gates/cardiac cycle. The activity distribution modelled uptake of (99m)Tc MIBI with normal perfusion and a regional wall motion defect. An analytical projector was used in the simulation and the filtered backprojection (FBP) algorithm was used in image reconstruction followed by spatial and temporal low-pass filtering with various cut-off frequencies. Then, we extracted 2D image slices from each time frame and reorganized them into a set of cine images. For the first model, we applied 2D spatial channels to the cine images and generated a set of feature vectors that were stacked for the images from different slices of the heart. The process was repeated for each of the 1,024 noise realizations, and CHO and receiver operating characteristics (ROC) analysis methodologies were applied to the ensemble of the feature vectors to compute areas under the ROC curves (AUCs). For the second model, a set of 4D space-time channels was developed and applied to the sets of cine images to produce space-time feature vectors to which the CHO methodology was applied. The AUC values of the second model showed better agreement (Spearman's rank correlation (SRC) coefficient = 0.8) to human observer results than those from the first model (SRC coefficient = 0.4). The agreement with human observers indicates the proposed 4D mathematical observer model provides a good predictor of the

  3. [Cardiac SPECT/CT: correlation between atherosclerosis, significant coronary artery stenoses and myocardial perfusion parameters in patients with known coronary artery disease].

    PubMed

    Ubleis, C; Rist, C; Griesshammer, I; Becker, A; Becker, C; Hacker, M

    2010-04-01

    Invasive coronary angiography (ICA) and CT angiography (CTA) both enable significant coronary artery stenoses to be detected, but they are not suitable for assessing their hemodynamic relevance. This can be accomplished using myocardial perfusion scintigraphy (MPS) which, however, has limited specificity and spatial resolution. Regarding patients with known coronary artery disease (CAD) it is furthermore important to stratify patient's individual risk for severe cardiac events to guide therapy management.The results of our investigations in 158 patients with CAD indicate that global and regional calcium scores (CAC) do not correlate with the presence of myocardial perfusion defects and significant coronary artery stenoses, respectively. However, published literature has reported CAC as being an independent predictor of long-time survival.For clinical purposes it seems that non-invasive diagnostics with CTA, MPS and CAC screening can be useful even in patients with known CAD. CAC and global scar burden enable long-term risk-stratification, whereas fusion of CTA and MPS is useful to detect the culprit lesion of relevant perfusion defects and to select options for revascularization. PMID:20333503

  4. Comparison of quantitative myocardial perfusion imaging CT to fluorescent microsphere-based flow from high-resolution cryo-images

    NASA Astrophysics Data System (ADS)

    Eck, Brendan L.; Fahmi, Rachid; Levi, Jacob; Fares, Anas; Wu, Hao; Li, Yuemeng; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) has the potential to provide quantitative measures of myocardial blood flow (MBF) which can aid the diagnosis of coronary artery disease. We evaluated the quantitative accuracy of MPI-CT in a porcine model of balloon-induced LAD coronary artery ischemia guided by fractional flow reserve (FFR). We quantified MBF at baseline (FFR=1.0) and under moderate ischemia (FFR=0.7) using MPI-CT and compared to fluorescent microsphere-based MBF from high-resolution cryo-images. Dynamic, contrast-enhanced CT images were obtained using a spectral detector CT (Philips Healthcare). Projection-based mono-energetic images were reconstructed and processed to obtain MBF. Three MBF quantification approaches were evaluated: singular value decomposition (SVD) with fixed Tikhonov regularization (ThSVD), SVD with regularization determined by the L-Curve criterion (LSVD), and Johnson-Wilson parameter estimation (JW). The three approaches over-estimated MBF compared to cryo-images. JW produced the most accurate MBF, with average error 33.3+/-19.2mL/min/100g, whereas LSVD and ThSVD had greater over-estimation, 59.5+/-28.3mL/min/100g and 78.3+/-25.6 mL/min/100g, respectively. Relative blood flow as assessed by a flow ratio of LAD-to-remote myocardium was strongly correlated between JW and cryo-imaging, with R2=0.97, compared to R2=0.88 and 0.78 for LSVD and ThSVD, respectively. We assessed tissue impulse response functions (IRFs) from each approach for sources of error. While JW was constrained to physiologic solutions, both LSVD and ThSVD produced IRFs with non-physiologic properties due to noise. The L-curve provided noise-adaptive regularization but did not eliminate non-physiologic IRF properties or optimize for MBF accuracy. These findings suggest that model-based MPI-CT approaches may be more appropriate for quantitative MBF estimation and that cryo-imaging can support the development of MPI-CT by providing spatial distributions of MBF.

  5. The Effect of Milk, Water and Lemon Juice on Various Subdiaphragmatic Activity-Related Artifacts in Myocardial Perfusion Imaging

    PubMed Central

    Malek, Hadi; Hedayati, Raheleh; Yaghoobi, Nahid; Bitarafan-Rajabi, Ahmad; Firoozabadi, Seyed Hassan; Rastgou, Feridoon

    2015-01-01

    Background: Subdiaphragmatic activity can produce subdiaphragmatic-related artifacts, which can degrade the quality of myocardial perfusion imaging (MPI). Objectives: We examined the impact of drinking milk, water, and lemon juice on different subdiaphragmatic-related artifacts by using 99mTc-sestamibi myocardial single-photon emission computed tomography (SPECT) in order to determine a feasible method for improving the image quality. Patients and Methods: A total of 179 patients (age 58 ± 9.6 years) were enrolled in this study. The patients were randomly divided into five groups. Ten minutes after injection of 740 MBq 99mTc-sestamibi in both pharmacologic stress and rest phases, the individuals in group 1 were given water and milk (125 mL of each); those in group 2 were given lemon juice (250 mL); group 3 was given milk (250 mL); and group 4 was given water (250 mL), whereas no intervention was performed in group 5. The study was double-blind for both subjects and data collectors. MPI was performed for all patients and image quality was controlled by 2 experienced nuclear physicians. Interfering activity was determined visually on reconstructed images and categorized as extracardiac normalization artifact, overlapping of activity, scattering of activity, and ramp filter artifact. Results: There were significant differences in terms of interfering activity among the five groups; group 3 (milk) had significantly lower interfering activity than other groups had, as defined by overlapping of activity (on both stress and rest images), ramp filter artifact (stress images), and scatter artifact (rest images) (P < 0.05). Furthermore, there was a significant difference in the incidence of good-quality images, with no interfering activity in group 3 in the resting state compared with the other groups in the study (P < 0.05). Conclusions: Drinking 250 mL of milk in either the stress phase or the rest phase of imaging diminishes interfering subdiaphragmatic-related artifacts

  6. Combined anatomical and functional imaging using coronary CT angiography and myocardial perfusion SPECT in symptomatic adults with abnormal origin of a coronary artery.

    PubMed

    Uebleis, C; Groebner, M; von Ziegler, F; Becker, A; Rischpler, C; Tegtmeyer, R; Becker, C; Lehner, S; Haug, A R; Cumming, P; Bartenstein, P; Franz, W M; Hacker, M

    2012-10-01

    There has been a lack of standardized workup guidelines for patients with congenital abnormal origin of a coronary artery from the opposite sinus (ACAOS). We aimed to evaluate the use of cardiac hybrid imaging using multi-detector row CT (MDCT) for coronary CT angiography (Coronary CTA) and stress-rest myocardial perfusion SPECT (MPS) for comprehensive diagnosis of symptomatic adult patients with ACAOS. Seventeen symptomatic patients (12 men; 54 ± 13 years) presenting with ACAOS underwent coronary CTA and MPS. Imaging data were analyzed by conventional means, and with additional use of 3D image fusion to allocate stress induced perfusion defects (PD) to their supplying coronary arteries. An anomalous RCA arose from the left anterior sinus in eight patients, an abnormal origin from the right sinus was detected in nine patients (5 left coronary arteries, LCA and 4 LCx). Five of the 17 patients (29%) demonstrated a reversible PD in MPS. There was no correlation between the anatomical variants of ACAOS and the presence of myocardial ischemia. Image fusion enabled the allocation of reversible PD to the anomalous vessel in three patients (two cases in the RCA and the other in the LCA territory); PD in two patients were allocated to the territory of artery giving rise to the anomalies, rather than the anomalies themselves. In a small cohort of adult symptomatic patients with ACAOS anomaly there was no relation found between the specific anatomical variant and the appearance of stress induced myocardial ischemia using cardiac hybrid imaging. PMID:22147107

  7. 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.

  8. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

    DOE PAGESBeta

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-10-09

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variationmore » of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. We find these results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.« less

  9. Image Reconstruction in Higher Dimensions: Myocardial Perfusion Imaging of Tracer Dynamics with Cardiac Motion Due to Deformation and Respiration

    PubMed Central

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-01-01

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases due to redistribution of the counts over the cardiac-respiratory gates. However, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images. PMID:26450115

  10. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

    SciTech Connect

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-10-09

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. We find these results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.

  11. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

    NASA Astrophysics Data System (ADS)

    Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-11-01

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.

  12. Myocardial infarct size quantification in mice by SPECT using a novel algorithm independent of a normal perfusion database

    PubMed Central

    2012-01-01

    Background There is a growing interest in developing non-invasive imaging techniques permitting infarct size (IS) measurements in mice. The aim of this study was to validate the high-resolution rodent Linoview single photon emission computed tomography (SPECT) system for non-invasive measurements of IS in mice by using a novel algorithm independent of a normal database, in comparison with histology. Methods Eleven mice underwent a left coronary artery ligature. Seven days later, animals were imaged on the SPECT 2h30 after injection of 173 ± 27 MBq of Tc-99m-sestamibi. Mice were subsequently killed, and their hearts were excised for IS determination with triphenyltetrazolium chloride (TTC) staining. SPECT images were reconstructed using the expectation maximization maximum likelihood algorithm, and the IS was calculated using a novel algorithm applied on the 20-segment polar map provided by the commercially available QPS software (Cedars-Sinai Medical Center, CA, USA). This original method is attractive by the fact that it does not require the implementation of a normal perfusion database. Results Reconstructed images allowed a clear delineation of the left ventricles borders in all mice. No significant difference was found between mean IS determined by SPECT and by TTC staining [37.9 ± 17.5% vs 35.6 ± 17.2%, respectively (P = 0.10)]. Linear regression analysis showed an excellent correlation between IS measured on the SPECT images and IS obtained with TTC staining (y = 0.95x + 0.03 (r = 0.97; P < 0.0001)), without bias, as demonstrated by the Bland-Altman plot. Conclusion Our results demonstrate the accuracy of the method for the measurement of myocardial IS in mice with the Linoview SPECT system. PMID:23272995

  13. Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration.

    PubMed

    Shrestha, Uttam M; Seo, Youngho; Botvinick, Elias H; Gullberg, Grant T

    2015-11-01

    Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images. PMID:26450115

  14. Cost-effectiveness of intracoronary flow velocity measurements and myocardial perfusion scintigraphy for management of intermediate coronary lesions

    PubMed Central

    Chamuleau, S.A.J.; Dijkgraaf, M.G.W.; van Eck-Smit, B.L.F.; Tijssen, J.G.P.; Piek, J.J.

    2005-01-01

    Background Coronary flow velocity reserve (CFVR) is an alternative for myocardial perfusion scintigraphy (SPECT) in assessing functional severity of coronary lesions. For the acceptance of CFVR in daily clinical decision-making, cost-effectiveness must be proven. Aim Economic evaluation of different diagnostic management strategies using CFVR compared with SPECT for making decisions regarding use of PTCA of an intermediate coronary lesion in patients with multivessel disease. Methods The incremental cost-effectiveness analysis was based on data from a prospective multicentre study in 201 patients with multivessel coronary artery disease. Four management strategies, assuming performance of angioplasty after positive test result(s), were compared: SPECT alone, CFVR alone (cut-off value of 2.0), and combined strategies of SPECT and CFVR with one ('extensive') or two ('restrictive') positive test(s). Probabilistic sensitivity analyses were performed using Monte Carlo simulation. Primary outcome was the probability of a cardiac event-free first year with respect to the intermediate lesion. Results A 10% event rate was observed, which was predominantly associated with ischaemia-driven revascularisations. A strategy based on CFVR was most effective. The restrictive strategy had the lowest costs and was most cost-effective; with increasing willingness-to-pay values (above €20,000) a CFVR-alone strategy became equally cost-effective. Conclusion It is mandatory to measure CFVR to decide upon angioplasty of the intermediate lesion in patients with multivessel coronary artery disease. This decision can be based on the restrictive strategy (i.e. performance of PTCA in case of abnormal test results of both SPECT and CFVR) or solely on CFVR, depending on society's willingness-to-pay to prevent cardiac events. ImagesFigure 3 PMID:25696495

  15. Myocardial Protection in Beating Heart Cardiac Surgery: I: Pre- or Post-Conditioning with Inhibition of the es-ENT1 Nucleoside Transporter and Adenosine Deaminase Attenuates Post-MI Reperfusion-Mediated Ventricular Fibrillation and Regional Contractile Dysfunction

    PubMed Central

    Abd-Elfattah, Anwar S. A.; Aly, Hamdy; Hanan, Scott; Wechsler, Andrew S.

    2012-01-01

    Objectives To determine the role of the es-ENT1 nucleoside transporter in post-MI reperfusion injury-mediated ventricular fibrillation (VFib) and regional dysfunction. We used erythro-9 (2-hydroxy-3-nonyl)-adenine (EHNA) and p-nitrobenzylthioinosine (NBMPR) to inhibit both adenosine deamination and transport in a canine model of off pump acute MI. Methods Anesthetized adult dogs (n= 37), instrumented to monitor systolic segmental shortening (SS %) and wall thickening (WT %) using sonomicrometry, underwent 90 minutes of LAD coronary artery occlusion and 120 minutes reperfusion. Myocardial coronary blood flow, ATP pool, infarct size and the incidents of ventricular fibrillation and cardioversions were also measured. Animals received an intravenous infusion of the vehicle (Control) or 100μM of EHNA and 25 μM NBMPR before ischemia (preconditioning, PreC group) or just before reperfusion (postconditioning, PostC group). Results In the control group, ATP depletion was associated with accumulation of more inosine than adenosine during ischemia and washed out during reperfusion. Myocardial adenosine and inosine were the major nucleosides in the PreC- and Post-C groups during ischemia and remained detectable during reperfusion, respectively. In both groups, recovery of systolic SS% and WT%, and reduction in the incidence of VFib (p<0.05 vs. Control group) coincided with retention of myocardial nucleosides. Infarct sizes in the three groups were not significantly different, independent of myocardial blood flow during ischemia. Conclusion PreC-or PostC with EHNA/NBMPR significantly reduced the incidence of ventricular fibrillation and cardioversions and attenuated regional contractile dysfunction mediated by post-MI reperfusion injury and that es-ENT1 plays a major role in these events. PMID:22329983

  16. Collimator optimization in myocardial perfusion SPECT using the ideal observer and realistic background variability for lesion detection and joint detection and localization tasks.

    PubMed

    Ghaly, Michael; Du, Yong; Links, Jonathan M; Frey, Eric C

    2016-03-01

    In SPECT imaging, collimators are a major factor limiting image quality and largely determine the noise and resolution of SPECT images. In this paper, we seek the collimator with the optimal tradeoff between image noise and resolution with respect to performance on two tasks related to myocardial perfusion SPECT: perfusion defect detection and joint detection and localization. We used the Ideal Observer (IO) operating on realistic background-known-statistically (BKS) and signal-known-exactly (SKE) data. The areas under the receiver operating characteristic (ROC) and localization ROC (LROC) curves (AUCd, AUCd+l), respectively, were used as the figures of merit for both tasks. We used a previously developed population of 54 phantoms based on the eXtended Cardiac Torso Phantom (XCAT) that included variations in gender, body size, heart size and subcutaneous adipose tissue level. For each phantom, organ uptakes were varied randomly based on distributions observed in patient data. We simulated perfusion defects at six different locations with extents and severities of 10% and 25%, respectively, which represented challenging but clinically relevant defects. The extent and severity are, respectively, the perfusion defect's fraction of the myocardial volume and reduction of uptake relative to the normal myocardium. Projection data were generated using an analytical projector that modeled attenuation, scatter, and collimator-detector response effects, a 9% energy resolution at 140 keV, and a 4 mm full-width at half maximum (FWHM) intrinsic spatial resolution. We investigated a family of eight parallel-hole collimators that spanned a large range of sensitivity-resolution tradeoffs. For each collimator and defect location, the IO test statistics were computed using a Markov Chain Monte Carlo (MCMC) method for an ensemble of 540 pairs of defect-present and -absent images that included the aforementioned anatomical and uptake variability. Sets of test statistics were computed

  17. Collimator optimization in myocardial perfusion SPECT using the ideal observer and realistic background variability for lesion detection and joint detection and localization tasks

    NASA Astrophysics Data System (ADS)

    Ghaly, Michael; Du, Yong; Links, Jonathan M.; Frey, Eric C.

    2016-03-01

    In SPECT imaging, collimators are a major factor limiting image quality and largely determine the noise and resolution of SPECT images. In this paper, we seek the collimator with the optimal tradeoff between image noise and resolution with respect to performance on two tasks related to myocardial perfusion SPECT: perfusion defect detection and joint detection and localization. We used the Ideal Observer (IO) operating on realistic background-known-statistically (BKS) and signal-known-exactly (SKE) data. The areas under the receiver operating characteristic (ROC) and localization ROC (LROC) curves (AUCd, AUCd+l), respectively, were used as the figures of merit for both tasks. We used a previously developed population of 54 phantoms based on the eXtended Cardiac Torso Phantom (XCAT) that included variations in gender, body size, heart size and subcutaneous adipose tissue level. For each phantom, organ uptakes were varied randomly based on distributions observed in patient data. We simulated perfusion defects at six different locations with extents and severities of 10% and 25%, respectively, which represented challenging but clinically relevant defects. The extent and severity are, respectively, the perfusion defect’s fraction of the myocardial volume and reduction of uptake relative to the normal myocardium. Projection data were generated using an analytical projector that modeled attenuation, scatter, and collimator-detector response effects, a 9% energy resolution at 140 keV, and a 4 mm full-width at half maximum (FWHM) intrinsic spatial resolution. We investigated a family of eight parallel-hole collimators that spanned a large range of sensitivity-resolution tradeoffs. For each collimator and defect location, the IO test statistics were computed using a Markov Chain Monte Carlo (MCMC) method for an ensemble of 540 pairs of defect-present and -absent images that included the aforementioned anatomical and uptake variability. Sets of test statistics were

  18. Nuclear Scan Strategy and Outcomes in Chest Pain Patients Value of Stress Testing with Dipyridamole or Adenosine

    PubMed Central

    Conti, Alberto; Mariannini, Yuri; Canuti, Erica; Petrova, Tetyana; Innocenti, Francesca; Zanobetti, Maurizio; Gallini, Chiara; Costanzo, Egidio

    2014-01-01

    Objective: To update the prognostic value of scan strategy with pharmacological stress agent in chest pain (CP) patients presenting with normal electrocardiography (ECG) and troponin. Methods: Two consecutive nonrandomized series of patients with CP and negative first-line workup inclusive of serial ECG, serial troponin, and echocardiography underwent myocardial perfusion imaging single photon emission computed tomography (SPECT) in the emergency department. Of 170 patients enrolled, 52 patients underwent dipyridamole-SPECT and 118 adenosine-SPECT. Patients with perfusion defects underwent angiography, whereas the remaining patients were discharged and followed-up. Primary endpoint was the composite of nonfatal myocardial infarction, unstable angina, revascularization, and cardiovascular death at follow-up or the presence of coronary stenosis > 50% at angiography. Results: At multivariate analysis, the presence of perfusion defects or hypertension was independent predictor of the primary endpoint. Sensitivity and negative predictive value were higher in patients subjected to adenosine-SPECT (95% and 99%, respectively) versus dipyridamole-SPECT (56% and 89%; yield 70% and 11%, respectively; P < 0.03). Of note, sensitivity, negative, and positive predictive values were high in patients with hypertension (100%, 93%, and 60%, respectively) or nonischemic echocardiography alterations (100%, 100%, and 100%, respectively). Conclusions: In CP patients, presenting with normal ECG and troponin, adenosine-SPECT adds incremental prognostic values to dipyridamole-SPECT. Costly scan strategy is more appropriate and avoids unnecessary angiograms in patients with hypertension or nonischemic echocardiography alterations. PMID:25191123

  19. Synthesis and Bio-Evaluation of New (18) F-Labeled Pyridaben Analogs with Improved Stability for Myocardial Perfusion Imaging in Mice.

    PubMed

    Mou, Tiantian; Zhao, Zuoquan; Zhang, Pu; Fang, Wei; Peng, Cheng; Lu, Jie; Wang, Qian; Ma, Yunchuan; Zhang, Xianzhong

    2015-09-01

    To improve the stability of (18) F-labeled pyridaben analogs for myocardial perfusion imaging, three new analogs of pyridaben ([(18) F]FPTP2, [(18) F]FPTP-P2, and [(18) F]FPTP-P3) were synthesized with 'side chain' modifications. The radiolabeled tracers and corresponding non-radioactive compounds were obtained by substituting tosyl group with (18/19) F. The effect of structure modification on myocardial targeting and physicochemical properties of new tracers were evaluated in vitro and in vivo. The total radiosynthesis time of these tracers was approximately 70-90 min with high decay-corrected radiochemical yields (36-65%) and good radiochemical purity (> 98%). These lipophilic tracers exhibited obvious improved stability in water. Studies of their biodistribution in normal Kunming mice demonstrated that [(18) F]FPTP2 exhibited very high initial heart uptake (39.70 ± 2.81 %ID/g at 2 min after injection) and low background in the liver, blood, and soft tissues. The heart-to-liver, heart-to-lung, and heart-to-blood ratios were 3.59, 19.34, and 67.34 at 15 min postinjection, respectively. Favorable myocardial targeting property and remarkable improvement of stability of [(18) F]FPTP2 suggest that the substitution of the phenyl 'sidechain' with other non-phenyl rings has no effect on the myocardial targeting property of (18) F-labeled pyridaben analogs. PMID:25529021

  20. Prevalence and predictors of mechanical dyssynchrony as defined by phase analysis in patients with left ventricular dysfunction undergoing gated SPECT myocardial perfusion imaging

    PubMed Central

    Samad, Zainab; Atchley, Allen E.; Trimble, Mark A.; Sun, Jie-Lena; Shaw, Linda K.; Pagnanelli, Robert; Chen, Ji; Garcia, Ernest V.; Iskandrian, Ami E.; Velazquez, Eric J.; Borges-Neto, Salvador

    2011-01-01

    Background A novel method to quantify dyssynchrony using phase analysis of single-photon emission computed tomography (SPECT) myocardial perfusion imaging has been developed. We sought to determine the prevalence of SPECT-derived mechanical dyssynchrony, and we report clinical variables which predict mechanical dyssynchrony in patients with left ventricular dysfunction. Methods We used a count-based Fourier analysis method to convert the regional myocardial counts from discrete frames per cardiac cycle into a continuous thickening function which allows resolution of the phase of the onset of myocardial contraction. The standard deviation of left ventricular phases (Phase SD) describes the regional phase dispersion as a measure of dyssynchrony. Significant dyssynchrony was defined as Phase SD ≥ 43°. 260 patients with left ventricular ejection fraction ≤35% were examined. Results The prevalence of mechanical dyssynchrony in the entire cohort of patients studied was 52%. Univariate predictors of Phase SD were age (P = .03), black race (P = .0005), QRS duration, EF, EDV, summed stress score (SSS), and summed rest score (SRS) (all P = <.0001). Black race, male gender, QRS EF, and SRS were independent predictors of SPECT-based mechanical dyssynchrony. Conclusions Significant SPECT-based mechanical dyssynchrony is relatively common among patients with left ventricular dysfunction. In a population of patients with predominantly ischemic heart disease referred for SPECT, a reduced EF, increasing QRS duration, severity and extent of myocardial scar on SPECT imaging are independent predictors of mechanical dyssynchrony and may serve to identify patients for dyssynchrony screening. PMID:21082299

  1. 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.

  2. Quantitative analysis of myocardial perfusion SPECT anatomically guided by co-registered 64-slice coronary CT angiography

    PubMed Central

    Slomka, Piotr J.; Cheng, Victor Y.; Dey, Damini; Woo, Jonghye; Ramesh, Amit; Kriekinge, Serge Van; Suzuki, Yasuzuki; Elad, Yaron; Karlsberg, Ronald; Berman, Daniel S.; Germano, Guido

    2012-01-01

    Aim Sequential testing by coronary computed tomography angiography (CTA) and myocardial perfusion SPECT (MPS) obtained on standalone scanners may be needed to diagnose coronary artery disease (CAD) in equivocal cases. We have developed an automated technique for MPS-CTA registration and demonstrate its utility for improved MPS quantification by guiding the co-registered physiological (MPS) with anatomical CTA information. Methods Automated registration of MPS left ventricular (LV) surfaces with CTA coronary trees was accomplished by iterative minimization of voxel differences between pre-segmented CTA volumes and “motion-frozen” MPS data. Studies of 35 sequential patients (26 males), mean age 67±12 years with 64-slice coronary CTA, MPS and with available results of the invasive coronary angiography performed within 3 months were retrospectively analyzed. 3D coronary vessels and CTA slices were extracted and fused with quantitative MPS results mapped on LV surfaces and MPS coronary regions. Automatically co-registered CTA images and extracted trees were used to correct the MPS contours and to adjust the standard vascular region definitions for MPS quantification. Results Automated co-registration of MPS and coronary CTA had the success rate of 96% as assessed visually; the average errors were 4.3±3.3 mm in translation and 1.5±2.6 deg in rotation on stress and 4.2±3.1 mm in translation and 1.7±3.2 deg in rotation on rest. MPS vascular region definition was adjusted in 17 studies and LV contours were adjusted in 11 studies using co-registered CTA images as a guide. CTA-guided MP analysis resulted in improved area under the receiver operator characteristics (ROC) curves for the detection of RCA and LCX lesions as compared to standard MPS analysis 0.84±0.08 vs. 0.70±0.11 for LCX (p = 0.03) and 0.92±0.05 vs. 0.75±0.09 (p=0.02) for RCA. Conclusions Software image co-registration of standalone coronary CTA and MPS obtained on separate scanners can be performed

  3. Coronary Computed Tomography Versus Radionuclide Myocardial Perfusion Imaging in Chest Pain Patients Admitted to Telemetry: A Randomized, Controlled Trial

    PubMed Central

    Levsky, Jeffrey M.; Spevack, Daniel M.; Travin, Mark I.; Menegus, Mark A.; Huang, Paul W.; Clark, Elana T.; Kim, Choo-won; Hirschhorn, Esther; Freeman, Katherine D.; Tobin, Jonathan N.; Haramati, Linda B.

    2016-01-01

    BACKGROUND Coronary computed tomography angiography plays an expanding role managing symptomatic patients with suspected coronary artery disease. Prospective intermediate-term outcomes are lacking. OBJECTIVE To compare coronary CT angiography with conventional non-invasive testing. DESIGN Randomized, controlled comparative effectiveness trial. SETTING Telemetry-monitored wards of one inner-city medical center. PATIENTS 400 acute chest pain patients (mean age 57); 63% women; 54% Hispanic, 37% African-American; low socioeconomic status. INTERVENTION Coronary CT angiography (CT) or radionuclide stress myocardial perfusion imaging (MPI). MEASUREMENTS The primary outcome was cardiac catheterization not leading to revascularization within one year. Secondary outcomes included length of stay, resource utilization and patient experience. Safety outcomes included death, major cardiovascular events and radiation exposure. RESULTS 30(15%) CT patients and 32(16%) MPI patients underwent cardiac catheterization within one year, of which 15(7.5%) and 20(10%), respectively, were not revascularized (-2.5% difference, 95%CI −8.6%–+3.5%; hazard ratio 0.77, 95%CI 0.40–1.49, p=0.44). Median length of stay was 28.9 hours for CT and 30.4 hours for MPI (p=0.057). Median follow-up was 40.4 months. For CT and MPI, the incidences of death (0.5% vs 3%, p=0.12), non-fatal cardiovascular events (4.5% vs 4.5%), re-hospitalization (43% vs 49%), emergency visit (63% vs 58%) and outpatient cardiology visit (23% vs 21%) were not different. Long-term, all-cause radiation was lower for CT (24 vs 29 milliSieverts, p<0.001). More CT patients graded their experience favorably (p=0.001) and would undergo the exam again (p=0.003). LIMITATIONS Single site study; primary outcome dependent on clinical management decisions. CONCLUSIONS There were no significant differences between CT and MPI in outcomes or resource utilization over 40 months. CT had lower associated radiation and was more positively

  4. Regularized Image Reconstruction Algorithms for Dual-Isotope Myocardial Perfusion SPECT (MPS) Imaging Using a Cross-Tracer Prior

    PubMed Central

    He, Xin; Cheng, Lishui; Fessler, Jeffrey A.

    2011-01-01

    In simultaneous dual-isotope myocardial perfusion SPECT (MPS) imaging, data are simultaneously acquired to determine the distributions of two radioactive isotopes. The goal of this work was to develop penalized maximum likelihood (PML) algorithms for a novel cross-tracer prior that exploits the fact that the two images reconstructed from simultaneous dual-isotope MPS projection data are perfectly registered in space. We first formulated the simultaneous dual-isotope MPS reconstruction problem as a joint estimation problem. A cross-tracer prior that couples voxel values on both images was then proposed. We developed an iterative algorithm to reconstruct the MPS images that converges to the maximum a posteriori solution for this prior based on separable surrogate functions. To accelerate the convergence, we developed a fast algorithm for the cross-tracer prior based on the complete data OS-EM (COSEM) framework. The proposed algorithm was compared qualitatively and quantitatively to a single-tracer version of the prior that did not include the cross-tracer term. Quantitative evaluations included comparisons of mean and standard deviation images as well as assessment of image fidelity using the mean square error. We also evaluated the cross tracer prior using a three-class observer study with respect to the three-class MPS diagnostic task, i.e., classifying patients as having either no defect, reversible defect, or fixed defects. For this study, a comparison with conventional ordered subsets-expectation maximization (OS-EM) reconstruction with postfiltering was performed. The comparisons to the single-tracer prior demonstrated similar resolution for areas of the image with large intensity changes and reduced noise in uniform regions. The cross-tracer prior was also superior to the single-tracer version in terms of restoring image fidelity. Results of the three-class observer study showed that the proposed cross-tracer prior and the convergent algorithms improved the

  5. Angiographic correlations of patients with small vessel disease diagnosed by adenosine-stress cardiac magnetic resonance imaging

    PubMed Central

    Pilz, Guenter; Klos, Markus; Ali, Eman; Hoefling, Berthold; Scheck, Roland; Bernhardt, Peter

    2008-01-01

    Cardiac magnetic resonance imaging (CMR) with adenosine-stress myocardial perfusion is gaining importance for the detection and quantification of coronary artery disease (CAD). However, there is little knowledge about patients with CMR-detected ischemia, but having no relevant stenosis as seen on coronary angiography (CA). The aims of our study were to characterize these patients by CMR and CA and evaluate correlations and potential reasons for the ischemic findings. 73 patients with an indication for CA were first scanned on a 1.5T whole-body CMR-scanner including adenosine-stress first-pass perfusion. The images were analyzed by two independent investigators for myocardial perfusion which was classified as subendocardial ischemia (n = 22), no perfusion deficit (n = 27, control 1), or more than subendocardial ischemia (n = 24, control 2). All patients underwent CA, and a highly significant correlation between the classification of CMR perfusion deficit and the degree of coronary luminal narrowing was found. For quantification of coronary blood flow, corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was evaluated for the left anterior descending (LAD), circumflex (LCX) and right coronary artery (RCA). The main result was that corrected TFC in all coronaries was significantly increased in study patients compared to both control 1 and to control 2 patients. Study patients had hypertension or diabetes more often than control 1 patients. In conclusion, patients with CMR detected subendocardial ischemia have prolonged coronary blood flow. In connection with normal resting flow values in CAD, this supports the hypothesis of underlying coronary microvascular impairment. CMR stress perfusion differentiates non-invasively between this entity and relevant CAD. PMID:18275591

  6. Towards Elimination of the Dark-Rim Artifact in First-Pass Myocardial Perfusion MRI: Removing Gibbs Ringing Effects Using Optimized Radial Imaging

    PubMed Central

    Sharif, Behzad; Dharmakumar, Rohan; LaBounty, Troy; Arsanjani, Reza; Shufelt, Chrisandra; Thomson, Louise; Merz, C. Noel Bairey; Berman, Daniel S.; Li, Debiao

    2014-01-01

    Purpose Subendocardial dark-rim artifacts (DRAs) remain a major concern in first-pass perfusion (FPP) myocardial MRI and may lower the diagnostic accuracy for detection of ischemia. A major source of the DRA is known to be the “Gibbs ringing” effect. We propose an optimized radial acquisition strategy aimed at eliminating ringing-induced DRAs in FPP. Theory and Methods By studying the underlying point spread function (PSF), we show that optimized radial sampling with a simple reconstruction method can eliminate the oscillations in the PSF that cause ringing artifacts. We conduct realistic MRI phantom experiments and in-vivo studies (n=12 healthy humans) to study the artifact behavior of the proposed acquisition scheme in comparison to a conventional Cartesian protocol. Results Simulations and phantom experiments verify the theoretical expectations. Our in-vivo studies show that optimized radial imaging is capable of significantly reducing DRAs in the early myocardial enhancement phase (during which the ringing effect is most prominent and may obscure perfusion defects) while providing equivalent resolution and similar image quality as conventional Cartesian imaging. Conclusion The developed technical framework and results demonstrate that, compared to conventional Cartesian techniques, optimized radial imaging with the proposed optimizations significantly reduces the prevalence and spatial extent of DRAs in FPP imaging. PMID:24030840

  7. Creation of an ensemble of simulated cardiac cases and a human observer study: tools for the development of numerical observers for SPECT myocardial perfusion imaging

    NASA Astrophysics Data System (ADS)

    O'Connor, J. Michael; Pretorius, P. Hendrik; Gifford, Howard C.; Licho, Robert; Joffe, Samuel; McGuiness, Matthew; Mehurg, Shannon; Zacharias, Michael; Brankov, Jovan G.

    2012-02-01

    Our previous Single Photon Emission Computed Tomography (SPECT) myocardial perfusion imaging (MPI) research explored the utility of numerical observers. We recently created two hundred and eighty simulated SPECT cardiac cases using Dynamic MCAT (DMCAT) and SIMIND Monte Carlo tools. All simulated cases were then processed with two reconstruction methods: iterative ordered subset expectation maximization (OSEM) and filtered back-projection (FBP). Observer study sets were assembled for both OSEM and FBP methods. Five physicians performed an observer study on one hundred and seventy-nine images from the simulated cases. The observer task was to indicate detection of any myocardial perfusion defect using the American Society of Nuclear Cardiology (ASNC) 17-segment cardiac model and the ASNC five-scale rating guidelines. Human observer Receiver Operating Characteristic (ROC) studies established the guidelines for the subsequent evaluation of numerical model observer (NO) performance. Several NOs were formulated and their performance was compared with the human observer performance. One type of NO was based on evaluation of a cardiac polar map that had been pre-processed using a gradient-magnitude watershed segmentation algorithm. The second type of NO was also based on analysis of a cardiac polar map but with use of a priori calculated average image derived from an ensemble of normal cases.

  8. A preliminary feasibility study of simultaneous dual-isotope imaging with a solid-state dedicated cardiac camera for evaluating myocardial perfusion and fatty acid metabolism.

    PubMed

    Ko, Toshiyuki; Utanohara, Yuko; Suzuki, Yasuhiro; Kurihara, Makiko; Iguchi, Nobuo; Umemura, Jun; Sumiyoshi, Tetsuya; Tomoike, Hitonobu

    2016-01-01

    Simultaneous dual-isotope SPECT imaging with 201Tl and (123)I-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) is used to study the perfusion-metabolism mismatch. It predicts post-ischemic functional recovery by detecting stunned myocardium. On the other hand, (99m)Tc-MIBI is another radioisotope widely used in myocardial perfusion imaging because of its better image quality and lower radiation exposure than 201Tl. However, since the photopeak energies of (99m)Tc and (123)I are very similar, crosstalk hampers the simultaneous use of these two radioisotopes. To overcome this problem, we conducted simultaneous dual-isotope imaging study using the D-SPECT scanner (Spectrum-Dynamics, Israel) which has a novel detector design and excellent energy resolution. We first conducted a basic experiment using cardiac phantom to simulate the condition of normal perfusion and impaired fatty acid metabolism. Subsequently, we prospectively recruited 30 consecutive patients who underwent successful percutaneous coronary intervention for acute myocardial infarction, and performed (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging within 5 days after reperfusion. Images were interpreted by two experienced cardiovascular radiologists to identify the infarcted and stunned areas based on the coronary artery territories. As a result, cardiac phantom experiment revealed no significant crosstalk between (99m)Tc and (123)I. In the subsequent clinical study, (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging in all participant yielded excellent image quality and detected infarcted and stunned areas correctly when compared with coronary angiographic findings. Furthermore, we were able to reduce radiation exposure to significantly approximately one-eighth. In conclusion, we successfully demonstrated the practical application of simultaneous assessment of myocardial perfusion and fatty acid metabolism by (99m)Tc-MIBI and (123)I-BMIPP using a D-SPECT cardiac scanner. Compared with conventional (201)Tl

  9. Differential impact of multi-focus fan beam collimation with L-mode and conventional systems on the accuracy of myocardial perfusion imaging: Quantitative evaluation using phantoms

    PubMed Central

    Onishi, Hideo; Matsutomo, Norikazu; Kangai, Yoshiharu; Saho, Tatsunori; Amijima, Hizuru

    2013-01-01

    Objective(s): A novel IQ-SPECT™ method has become widely used in clinical studies. The present study compares the quality of myocardial perfusion images (MPI) acquired using the IQ-SPECT™ (IQ-mode), conventional (180° apart: C-mode) and L-mode (90° apart: L-mode) systems. We assessed spatial resolution, image reproducibility and quantifiability using various physical phantoms. Methods: SPECT images were acquired using a dual-headed gamma camera with C-mode, L-mode, and IQ-mode acquisition systems from line source, pai and cardiac phantoms containing solutions of 99mTc. The line source phantom was placed in the center of the orbit and at ± 4.0, ± 8.0, ± 12.0, ± 16.0 and ± 20.0 cm off center. We examined quantifiability using the pai phantom comprising six chambers containing 0.0, 0.016, 0.03, 0.045, 0.062, and 0.074 MBq/mL of 99m-Tc and cross-calibrating the SPECT counts. Image resolution and reproducibility were quantified as myocardial wall thickness (MWT) and %uptake using polar maps. Results: The full width at half maximum (FWHM) of the IQ-mode in the center was increased by 11% as compared with C-mode, and FWHM in the periphery was increased 41% compared with FWHM at the center. Calibrated SPECT counts were essentially the same when quantified using IQ-and C-modes. IQ-SPECT images of MWT were significantly improved (P<0.001) over L-mode, and C-mode SPECT imaging with IQ-mode became increasingly inhomogeneous, both visually and quantitatively (C-mode vs. L-mode, ns; C-mode vs. IQ-mode, P<0.05). Conclusion: Myocardial perfusion images acquired by IQ-SPECT were comparable to those acquired by conventional and L-mode SPECT, but with significantly improved resolution and quality. Our results suggest that IQ-SPECT is the optimal technology for myocardial perfusion SPECT imaging. PMID:27408847

  10. Effects of Curcumin on Parameters of Myocardial Oxidative Stress and of Mitochondrial Glutathione Turnover in Reoxygenation after 60 Minutes of Hypoxia in Isolated Perfused Working Guinea Pig Hearts

    PubMed Central

    Ilyas, Ermita I. Ibrahim; Nur, Busjra M.; Laksono, Sonny P.; Bahtiar, Anton; Estuningtyas, Ari; Vitasyana, Caecilia; Kusmana, Dede; Suyatna, Frans D.; Tadjudin, Muhammad Kamil; Freisleben, Hans-Joachim

    2016-01-01

    In cardiovascular surgery ischemia-reperfusion injury is a challenging problem, which needs medical intervention. We investigated the effects of curcumin on cardiac, myocardial, and mitochondrial parameters in perfused isolated working Guinea pig hearts. After preliminary experiments to establish the model, normoxia was set at 30 minutes, hypoxia was set at 60, and subsequent reoxygenation was set at 30 minutes. Curcumin was applied in the perfusion buffer at 0.25 and 0.5 μM concentrations. Cardiac parameters measured were afterload, coronary and aortic flows, and systolic and diastolic pressure. In the myocardium histopathology and AST in the perfusate indicated cell damage after hypoxia and malondialdehyde (MDA) levels increased to 232.5% of controls during reoxygenation. Curcumin protected partially against reoxygenation injury without statistically significant differences between the two dosages. Mitochondrial MDA was also increased in reoxygenation (165% of controls), whereas glutathione was diminished (35.2%) as well as glutathione reductase (29.3%), which was significantly increased again to 62.0% by 0.05 μM curcumin. Glutathione peroxidase (GPx) was strongly increased in hypoxia and even more in reoxygenation (255% of controls). Curcumin partly counteracted this increase and attenuated GPx activity independently in hypoxia and in reoxygenation, 0.25 μM concentration to 150% and 0.5 μM concentration to 200% of normoxic activity. PMID:26904113

  11. 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.

  12. Thallium myocardial perfusion scans for the assessment of right ventricular hypertrophy in patients with cystic fibrosis. A comparison with other noninvasive techniques

    SciTech Connect

    Newth, C.J.; Corey, M.L.; Fowler, R.S.; Gilday, D.L.; Gross, D.; Mitchell, I.

    1981-01-01

    The incidence of right ventricular hypertrophy in 32 patients with cystic fibrosis was studied using thallium 201 (TI-201) myocardial perfusion scans, and compared with other noninvasive techniques including electrocardiography, vectorcardiography, and M-mode echocardiography. The patients (mean age, 17.3 yr; range, 7 to 33) had a wide range of clinical and pulmonary abnormalities (mean Shwachman-Kulczycki score, 66.6). In the total study group, TI-201 scans, like the vectorcardiograms and the M-mode echocardiograms, gave a surprisingly high proportion of positive predictions for right ventricular hypertrophy (RVH) (44%). The correlations with all other noninvasive methods were uniformly poor, so caution must be exercised in using this technique to predict early RVH in order to follow the natural history of cor pulmonale in cystic fibrosis. At the time of the study, 6 patients had clinical evidence of right ventricular failure, and in this disease setting must have had RVH. In 3 patients, RVH was confirmed at autopsy, and it was successfully predicted by TI-201 scans in 5 of the 6 patients. The false negative scan may have been due to regional myocardial ischemia secondary to severe right ventricular failure. In contrast, the vectorcardiogram, using Fowler's new criteria, made a successful prediction of RVH in all 6 patients, and the electro cardiogram in only 3. Although the M-mode echocardiogram was abnormal in all patients, it would have predicted RVH (with increased right ventricular anterior wall thickness) in only 1 patient. We concluded that TI-201 myocardial perfusion cans are good at confirming RVH in cases with established right ventricular failure, but have no advantage over vectorcardiographic assessments, which are logistically easier to perform and carry no radiation risks.

  13. [The Optimal Reconstruction Parameters by Scatter and Attenuation Corrections Using Multi-focus Collimator System in Thallium-201 Myocardial Perfusion SPECT Study].

    PubMed

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

    2015-11-01

    The aim of this study was to reveal the optimal reconstruction parameters of ordered subset conjugates gradient minimizer (OSCGM) by no correction (NC), attenuation correction (AC), and AC+scatter correction (ACSC) using IQ-single photon emission computed tomography (SPECT) system in thallium-201 myocardial perfusion SPECT. Myocardial phantom acquired two patterns, with or without defect. Myocardial images were performed 5-point scale visual score and quantitative evaluations using contrast, uptake, and uniformity about the subset and update (subset×iteration) of OSCGM and the full width at half maximum (FWHM) of Gaussian filter by three corrections. We decided on optimal reconstruction parameters of OSCGM by three corrections. The number of subsets to create suitable images were 3 or 5 for NC and AC, 2 or 3 for ACSC. The updates to create suitable images were 30 or 40 for NC, 40 or 60 for AC, and 30 for ACSC. Furthermore, the FWHM of Gaussian filters were 9.6 mm or 12 mm for NC and ACSC, 7.2 mm or 9.6 mm for AC. In conclusion, the following optimal reconstruction parameters of OSCGM were decided; NC: subset 5, iteration 8 and FWHM 9.6 mm, AC: subset 5, iteration 8 and FWHM 7.2 mm, ACSC: subset 3, iteration 10 and FWHM 9.6 mm. PMID:26596202

  14. Evaluation of 99mTcN-MPO as a New Myocardial Perfusion Imaging Agent in Normal Dogs and in an Acute Myocardial Infarction Canine Model: Comparison with 99mTc-Sestamibi

    PubMed Central

    Bu, Lihong; Li, Renfei; Jin, Zhongnan; Wen, Xiaofei; Liu, Shuang; Yang, Baofeng; Shen, Baozhong; Chen, Xiaoyuan

    2010-01-01

    Purpose 99mTcN-MPO ([99mTcN(mpo)(PNP5)]+: mpo=2-mercaptopyridine oxide and PNP5=N-ethoxyethyl-N,N-bis[2-(bis(3-methoxypropyl)phosphino)ethyl]amine) is a cationic 99mTc-nitrido complex, which has favorable biodistribution and myocardial uptake with rapid liver clearance in Sprague Dawley rats. The objective of this study was to compare the biodistribution and pharmacokinetics of 99mTcN-MPO and 99mTc-Sestamibi in normal dogs, and to evaluate the potential of 99mTcN-MPO as a myocardial perfusion agent in canines with acute myocardial infarction. Methods Five normal mongrel dogs were injected intravenously with 99mTcN-MPO. Venous blood samples were collected via a femoral vein catheter at 0.5, 1, 2, 3, 4, 5, 10, 20, 30, 40, 60, and 90 min post-injection (p.i.). Anterior-posterior planar images were acquired by γ-camera at 10, 20, 30, 60, 90, and 120 min p.i. Regions of interest (ROIs) were drawn around the heart, liver, and lungs. The heart/liver and heart/lung ratios were calculated by dividing the mean counts in heart ROI by the mean counts in the liver and lung ROI, respectively. For comparison, 99mTc-sestamibi was also evaluated in the same five dogs. The interval period between the two examinations was 1 week to eliminate possible interference between these two radiotracers. In addition, single positron emission computed tomography (SPECT) images in the canine infarct model were collected 24 h after myocardial infarction at 30 and 60 min after the administration of 99mTcN-MPO (n=4) or 99mTc-Sestamibi (n=4). Results It was found that 99mTcN-MPO and 99mTc-Sestamibi displayed very similar blood clearance characteristics during the first 90 min p.i. Both 99mTcN-MPO and 99mTc-Sestamibi had a rapid blood clearance with less than 50% of initial radioactivity remaining at 1 min and less than 5% at 30 min p.i. 99mTcN-MPO and 99mTc-Sestamibi both showed good heart/lung contrast. The heart/liver ratio of 99mTcN-MPO increased with time (0.53±0.06 at 10 min, 0.90±0.062 at

  15. The association of increased stomach wall radiotracer uptake with prolonged use of omeprazole capsules on myocardial perfusion imaging (MPI) using 99mTc-sestamibi SPECT.

    PubMed

    Javadi, Hamid; Jallalat, Sara; Semnani, Shahriar; Mogharrabi, Mehdi; Nabipour, Iraj; Tabib, Seyed Masoud; Abbaszadeh, Moloud; Assadi, Majid

    2013-01-01

    Myocardial perfusion imaging (MPI) is widely used in routine practice for diagnosis and risk stratification of coronary artery disease (CAD). Intense curvilinear activity in the stomach wall of a patient was seen on MPI raw data. This phenomenon was completely dissimilar to the familiar intraluminal gastric reflux of sestamibi. This observed activity could have resulted in false-positive or false-negative artifacts - and inaccurate diagnosis - of the inferior wall of the left ventricle after MPI processing. On further exploration, the current researchers found that the patient had a history of 10-year Omeprazole capsule consumption. The authors present this infrequent case of intense stomach uptake to stress the related clinical and diagnostic implications with the aim to stimulate acute awareness of possible, unexpected infringements on image quality that could potentially interfere with accurate interpretation of the data. PMID:24068640

  16. MR Assessment of Myocardial Perfusion, Viability, and Function after Intramyocardial Transfer of VM202, a New Plasmid Human Hepatocyte Growth Factor in Ischemic Swine Myocardium1

    PubMed Central

    Saeed, Maythem; Martin, Alastair; Ursell, Phillip; Do, Loi; Bucknor, Matt; Higgins, Charles B.; Saloner, David

    2008-01-01

    Purpose: VM202, a newly constructed plasmid human hepatocyte growth factor, was transferred intramyocardially after infarction for the purpose of evaluating this strategy as a therapeutic approach for protection from left ventricular (LV) remodeling. Materials and Methods: The institutional animal care and use committee approved this study. Pigs underwent coronary artery occlusion and reperfusion and served as either control (n = 8) or VM202-treated (n = 8) animals. VM202 was transferred intramyocardially into four infarcted and four periinfarcted sites. Cardiac magnetic resonance (MR) imaging (cine, perfusion, delayed enhancement) was performed in acute (3 days) and chronic (50 days ± 3 [standard error of the mean]) infarction. Histopathologic findings were used to characterize and quantify neovascularization. The t test was utilized to compare treated and control groups and to assess changes over time. Results: In acute infarction, MR imaging estimates of function, perfusion, and viability showed no difference between the groups. In chronic infarction, however, VM202 increased maximum signal intensity and upslope at first-pass perfusion imaging and reduced infarct size at perfusion and delayed-enhancement imaging. These changes were associated with a decrease in end-diastolic (2.15 mL/kg ± 0.12 to 1.73 mL/kg ± 0.10, P < .01) and end-systolic (1.33 mL/kg ± 0.07 to 0.92 mL/kg ± 0.08, P < .001) volumes and an increase in ejection fraction (38.2% ± 1.3 to 47.0% ± 1.8, P < .001). In contrast, LV function deteriorated further in control animals. Compared with control animals, VM202-treated animals revealed peninsulas and/or islands of viable myocardium in infarcted and periinfarcted regions and greater number of capillaries (218 per square millimeter ± 19 vs 119 per square millimeter ± 17, P < .05) and arterioles (21 per square millimeter ± 4 vs 3 per square millimeter ± 1, P < .001). Conclusion: Intramyocardial transfer of VM202 improved myocardial

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

    SciTech Connect

    Mahmarian, J.J.; Pratt, C.M.; Cocanougher, M.K.; Verani, M.S. )

    1990-10-01

    The extent of abnormally perfused myocardium was compared in patients with and without chest pain during treadmill exercise from a large, relatively low-risk consecutive patient population (n = 356) referred for quantitative thallium-201 single-photon emission computed tomography (SPECT). All patients had concurrent coronary angiography. Patients were excluded if they had prior coronary angioplasty or bypass surgery. Tomographic images were assessed visually and from computer-generated polar maps. Chest pain during exercise was as frequent in patients with normal coronary arteries (12%) as in those with significant (greater than 50% stenosis) coronary artery disease (CAD) (14%). In the 219 patients with significant CAD, silent ischemia was fivefold more common than symptomatic ischemia (83% versus 17%, p = 0.0001). However, there were no differences in the extent, severity, or distribution of coronary stenoses in patients with silent or symptomatic ischemia. Our major observation was that the extent of quantified SPECT perfusion defects was nearly identical in patients with (20.9 +/- 15.9%) and without (20.5 +/- 15.6%) exertional chest pain. The sensitivity for detecting the presence of CAD was significantly improved with quantitative SPECT compared with stress electrocardiography (87% versus 65%, p = 0.0001). Although scintigraphic and electrocardiographic evidence of exercise-induced ischemia were comparable in patients with chest pain (67% versus 73%, respectively; p = NS), SPECT was superior to stress electrocardiography for detecting silent myocardial ischemia. The majority of patients in this study with CAD who developed ischemia during exercise testing were asymptomatic, although they exhibited an angiographic profile and extent of abnormally perfused myocardium similar to those of patients with symptomatic ischemia.

  18. Serial thallium-201 imaging at rest in patients with unstable and stable angina pectoris: relationship of myocardial perfusion at rest to presenting clinical syndrome

    SciTech Connect

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

    1983-07-01

    In order to determine whether there are differences in myocardial perfusion at rest among patients with various unstable and stable angina syndromes, serial thallium-201 imaging was performed at rest in 19 patients presenting with rapidly worsening exertional angina (unstable angina, group A), 12 patients with rest angina alone without exertional symptoms (unstable angina, group B), and 34 patients with chronic stable angina. No patient had an episode of angina within 4 hours of study. Nineteen of 19 (100%) patients in group A demonstrated transient defects compared to only 3 of 12 (25%) patients in group B (p less than 0.0001) and 4 of 34 (12%) stable angina patients (p less than 0.0001). The majority of zones demonstrating transient defects in group A were associated with hypokinesis of the corresponding left ventriculogram segment without associated ECG evidence of previous infarction. There were no significant differences in the frequency of persistent thallium defects, severity of angiographic coronary artery disease, or frequency of regional wall motion abnormalities of myocardial segments supplied by stenotic coronary arteries among the three groups of patients. Transient defects have been shown to reflect reduction in regional coronary blood flow to viable myocardium. Therefore, we conclude that regional resting hypoperfusion of viable myocardium is far more common in patients with exertional unstable angina symptoms than in patients with rest angina alone or chronic stable angina.

  19. Application of task-based measures of image quality to optimization and evaluation of three-dimensional reconstruction-based compensation methods in myocardial perfusion SPECT.

    PubMed

    Frey, Eric C; Gilland, Karen L; Tsui, Benjamin M W

    2002-09-01

    In this paper, we apply the channelized Hotelling observer (CHO) using a defect detection task to the optimization and evaluation of three-dimensional iterative reconstruction-based compensation methods for myocardial perfusion single-photon emission computed tomography (SPECT). We used a population of 24 mathematical cardiac-torso phantoms that realistically model the activity and attenuation distribution in three classes of patients: females, and males with flat diaphragms and raised diaphragms. Projection data were generated and subsequently reconstructed using methods based on the ordered subsets-expectation maximization (OSEM) algorithm. The methods evaluated included compensation for attenuation, detector response blurring, and scatter in various combinations. We applied the CHO to optimize the number of iterations for OSEM and the cutoff frequency and order of a three-dimensional postreconstruction Butterworth filter. Using the optimal parameters, we then compared the compensation methods. The index of comparison in these studies was the area under the receiver operating characteristics curve (AUC) for the CHO. We found that attenuation compensation with either detector response or scatter compensation gave statistically significant increases in the AUC compared to attenuation compensation alone. The greatest increase in the AUC occurred when all three compensations were applied. These results indicate that compensation for detector response and scatter, in addition to attenuation compensation, will improve defect detectability in myocardial SPECT images. PMID:12564872

  20. Prognostic value of thallium-201 myocardial perfusion imaging in patients with unstable angina who respond to medical treatment

    SciTech Connect

    Brown, K.A. )

    1991-04-01

    Although the prognostic value of thallium-201 imaging is well established, its ability to risk stratify patients who present with unstable angina is unclear. Fifty-two consecutive patients admitted with unstable angina who responded to medical treatment and underwent stress thallium-201 imaging within 1 week of discharge were studied. Patients were followed up for 39 +/- 11 months. Cardiac events included cardiac death (n = 3), nonfatal myocardial infarction (n = 4) and admission for unstable angina or revascularization (n = 17). The ability of thallium-201 data (redistribution, fixed defects, normal) to predict cardiac events was compared with clinical data (age, gender, prior myocardial infarction, anginal syndrome, rest and stress electrocardiogram) and cardiac catheterization data using logistic regression. Thallium-201 redistribution was the only significant predictor of cardiac death or nonfatal myocardial infarction (p less than 0.05). The number of myocardial segments with thallium-201 redistribution (p less than 0.0005) and a history of prior myocardial infarction (p less than 0.05) were the only significant predictors of all cardiac events. Cardiac death or nonfatal myocardial infarction occurred more frequently in patients with thallium-201 redistribution (6 (26%) of 23) than in those without redistribution (1 (3%) of 29, p less than 0.05). Similarly, total cardiac events developed more frequently in patients with thallium-201 redistribution (p less than 0.001). Stress thallium-201 imaging has important prognostic value in patients admitted with unstable angina who respond to medical therapy and can identify subgroups at high versus low risk for future cardiac events.

  1. New approach to quantitation of exercise thallium-201 scintigraphy before and after an intervention: application to define the impact of coronary angioplasty on regional myocardial perfusion

    SciTech Connect

    Lim, Y.L.; Okada, R.D.; Chesler, D.A.; Block, P.C.; Boucher, C.A.; Pohost, G.M.

    1984-10-01

    We have developed a new computer method designed to quantitate regional myocardial thallium-201 (TI-201) initial distribution, redistribution, and clearance rate. In addition, this computer method permits the generation of functional images to compare two thallium images in the same projection to one another. These functional images can be used to demonstrate the extent of redistribution and the extent of change in regional perfusion before and after an intervention. To validate and apply this new computer technique, exercise TI-201 myocardial images obtained before and 1 week after percutaneous transluminal coronary angioplasty (PTCA) were analyzed in 20 patients with isolated left anterior descending coronary artery disease. Significant improvement in initial TI-201 activity, expressed as a percentage of maximal myocardial activity, was present in the anterior (71.9 +/- 12.0 to 84.1 +/- 11.5%, p less than 0.001) and septal (66.7 +/- 15.4 to 75.2 +/- 11.0%, p less than 0.05) regions of the left ventricle 1 week after PTCA. This increase in relative anterior wall TI-201 uptake was associated with a significant reduction in the amount of TI-201 redistribution between initial and delayed postexercise images (14.7 +/- 14.6 to 3.0 +/- 13.2%, p less than 0.05) as well as an increase in TI-201 clearance rate (t 1/2 from 8.8 +/- 4.4 to 4.3 +/- 2.5 hours, p less than 0.001). Quantitative analysis of TI-201 scans demonstrated improvement in 14 of 20 patients following PTCA. Computer-derived functional difference images depicted diminution in the extent of ischemia as manifested by redistribution of TI-201.

  2. Quantitative Upright–Supine High-Speed SPECT Myocardial Perfusion Imaging for Detection of Coronary Artery Disease: Correlation with Invasive Coronary Angiography

    PubMed Central

    Nakazato, Ryo; Tamarappoo, Balaji K.; Kang, Xingping; Wolak, Arik; Kite, Faith; Hayes, Sean W.; Thomson, Louise E.J.; Friedman, John D.; Berman, Daniel S.; Slomka, Piotr J.

    2011-01-01

    A recently developed camera system for high-speed SPECT (HS-SPECT) myocardial perfusion imaging shows excellent correlation with conventional SPECT. Our goal was to test the diagnostic accuracy of an automated quantification of combined upright and supine myocardial SPECT for detection of coronary artery disease (CAD) (≥70% luminal diameter stenosis or, in left main coronary artery, ≥50% luminal diameter stenosis) in comparison to invasive coronary angiography (ICA). Methods We studied 142 patients undergoing upright and supine HS-SPECT, including 56 consecutive patients (63% men; mean age 6 ± SD, 64 ± 13 y; 45% exercise stress) without known CAD who underwent diagnostic ICA within 6 mo of HS-SPECT and 86 consecutive patients with a low likelihood of CAD. Reference limits for upright and supine HS-SPECT were created from studies of patients with a low likelihood of CAD. Automated software adopted from supine–prone analysis was used to quantify the severity and extent of perfusion abnormality and was expressed as total perfusion deficit (TPD). TPD was obtained for upright (U-TPD), supine (S-TPD), and combined upright–supine acquisitions (C-TPD). Stress U-TPD ≥ 5%, S-TPD ≥ 5%, and C-TPD ≥ 3% myocardium were considered abnormal for per-patient analysis, and U-TPD, S-TPD, and C-TPD ≥ 2% in each coronary artery territory were considered abnormal for per-vessel analysis. Results On a per-patient basis, the sensitivity was 91%, 88%, and 94% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 59%, 73%, and 86% for U-TPD, S-TPD, and C-TPD, respectively. C-TPD had a larger area under the receiver-operating-characteristic curve than U-TPD or S-TPD for identification of stenosis ≥ 70% (0.94 vs. 0.88 and 0.89, P < 0.05 and not significant, respectively). On a per-vessel basis, the sensitivity was 67%, 66%, and 69% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 91%, 94%, and 97% for U-TPD, S-TPD, and C-TPD, respectively (P = 0

  3. Tolerance and safety of pharmacologic coronary vasodilation with adenosine in association with thallium-201 scintigraphy in patients with suspected coronary artery disease

    SciTech Connect

    Abreu, A.; Mahmarian, J.J.; Nishimura, S.; Boyce, T.M.; Verani, M.S. )

    1991-09-01

    Adenosine thallium-201 myocardial scintigraphy is a promising test for coronary artery disease detection, but its safety has not been reported in large patient cohorts. Accordingly, the tolerance and safety profile of adenosine infusion were analyzed in 607 patients (351 men, 256 women, mean age 63 {plus minus} 11 years) undergoing this test either because of suspected coronary artery disease (Group I, n = 482) or for risk stratification early (5.2 {plus minus} 2.8 days) after myocardial infarction (Group II, n = 125). Adenosine increased the heart rate from 74.5 {plus minus} 14.0 to 91.8 {plus minus} 15.9 beats/min (p less than 0.001) and decreased systolic blood pressure from 137.8 {plus minus} 26.8 to 120.7 {plus minus} 26.1 mm Hg (p less than 0.001). Side effects were frequent and similar in both groups. Flushing occurred in 35%, chest pain in 34%, headache in 21% and dyspnea in 19% of patients. Only 35.6% of Group I patients with chest pain during adenosine infusion had concomitant transient perfusion abnormalities, compared with 60.7% of Group II patients (p less than 0.05). First- and second-degree AV block occurred in 9.6% and 3.6% of patients, respectively, and ischemic ST changes in 12.5% of cases. Concomitance of chest pain and ischemic ST depression was uncommon (6%) but, when present, predicted perfusion abnormalities in 73% of patients. Most side effects ceased rapidly after stopping the adenosine infusion. The side effects were severe in only 1.6% of patients and in only six patients (1%) was it necessary to discontinue the infusion. No serious adverse reactions such as acute myocardial infarction or death occurred.

  4. Recent developments in adenosine receptor ligands and their potential as novel drugs☆

    PubMed Central

    Müller, Christa E.; Jacobson, Kenneth A.

    2012-01-01

    Medicinal chemical approaches have been applied to all four of the adenosine receptor (AR) subtypes (A1, A2A, A2B, and A3) to create selective agonists and antagonists for each. The most recent class of selective AR ligands to be reported is the class of A2BAR agonists. The availability of these selective ligands has facilitated research on therapeutic applications of modulating the ARs and in some cases has provided clinical candidates. Prodrug approaches have been developed which improve the bioavailability of the drugs, reduce side-effects, and/or may lead to site-selective effects. The A2A agonist regadenoson (Lexiscan®), a diagnostic drug for myocardial perfusion imaging, is the first selective AR agonist to be approved. Other selective agonists and antagonists are or were undergoing clinical trials for a broad range of indications, including capadenoson and tecadenoson (A1 agonists) for atrial fibrillation, or paroxysmal supraventricular tachycardia, respectively, apadenoson and binodenoson (A2A agonists) for myocardial perfusion imaging, preladenant (A2A antagonist) for the treatment of Parkinson’s disease, and CF101 and CF102 (A3 agonists) for inflammatory diseases and cancer, respectively. This article is part of a Special Issue entitled: “Adenosine Receptors”. PMID:21185259

  5. Cardioprotective Effect of Licochalcone D against Myocardial Ischemia/Reperfusion Injury in Langendorff-Perfused Rat Hearts

    PubMed Central

    Wang, Peng-long; Lu, Jie; Zhao, Hong; Liu, Shi-han; Zheng, Qiu-sheng; Li, Chang-gui

    2015-01-01

    Flavonoids are important components of ‘functional foods’, with beneficial effects on cardiovascular function. The present study was designed to investigate whether licochalcone D (LD) could be a cardioprotective agent in ischemia/reperfusion (I/R) injury and to shed light on its possible mechanism. Compared with the I/R group, LD treatment enhanced myocardial function (increased LVDP, dp/dtmax, dp/dtmin, HR and CR) and suppressed cardiac injury (decreased LDH, CK and myocardial infarct size). Moreover, LD treatment reversed the I/R-induced cleavage of caspase-3 and PARP, resulting in a significant decrease in proinflammatory factors and an increase in antioxidant capacity in I/R myocardial tissue. The mechanisms underlying the antiapoptosis, antiinflammation and antioxidant effects were related to the activation of the AKT pathway and to the blockage of the NF-κB/p65 and p38 MAPK pathways in the I/R-injured heart. Additionally, LD treatment markedly activated endothelial nitric oxide synthase (eNOS) and reduced nitric oxide (NO) production. The findings indicated that LD had real cardioprotective potential and provided support for the use of LD in myocardial I/R injury. PMID:26058040

  6. Cardioprotective Effect of Licochalcone D against Myocardial Ischemia/Reperfusion Injury in Langendorff-Perfused Rat Hearts.

    PubMed

    Yuan, Xuan; Niu, Hai-tao; Wang, Peng-long; Lu, Jie; Zhao, Hong; Liu, Shi-han; Zheng, Qiu-sheng; Li, Chang-gui

    2015-01-01

    Flavonoids are important components of 'functional foods', with beneficial effects on cardiovascular function. The present study was designed to investigate whether licochalcone D (LD) could be a cardioprotective agent in ischemia/reperfusion (I/R) injury and to shed light on its possible mechanism. Compared with the I/R group, LD treatment enhanced myocardial function (increased LVDP, dp/dtmax, dp/dtmin, HR and CR) and suppressed cardiac injury (decreased LDH, CK and myocardial infarct size). Moreover, LD treatment reversed the I/R-induced cleavage of caspase-3 and PARP, resulting in a significant decrease in proinflammatory factors and an increase in antioxidant capacity in I/R myocardial tissue. The mechanisms underlying the antiapoptosis, antiinflammation and antioxidant effects were related to the activation of the AKT pathway and to the blockage of the NF-κB/p65 and p38 MAPK pathways in the I/R-injured heart. Additionally, LD treatment markedly activated endothelial nitric oxide synthase (eNOS) and reduced nitric oxide (NO) production. The findings indicated that LD had real cardioprotective potential and provided support for the use of LD in myocardial I/R injury. PMID:26058040

  7. Real-time cine and myocardial perfusion with treadmill exercise stress cardiovascular magnetic resonance in patients referred for stress SPECT

    PubMed Central

    2010-01-01

    Background To date, stress cardiovascular magnetic resonance (CMR) has relied on pharmacologic agents, and therefore lacked the physiologic information available only with exercise stress. Methods 43 patients age 25 to 81 years underwent a treadmill stress test incorporating both Tc99m SPECT and CMR. After rest Tc99m SPECT imaging, patients underwent resting cine CMR. Patients then underwent in-room exercise stress using a partially modified treadmill. 12-lead ECG monitoring was performed throughout. At peak stress, Tc99m was injected and patients rapidly returned to their prior position in the magnet for post-exercise cine and perfusion imaging. The patient table was pulled out of the magnet for recovery monitoring. The patient was sent back into the magnet for recovery cine and resting perfusion followed by delayed post-gadolinium imaging. Post-CMR, patients went to the adjacent SPECT lab to complete stress nuclear imaging. Each modality's images were reviewed blinded to the other's results. Results Patients completed on average 9.3 ± 2.4 min of the Bruce protocol. Stress cine CMR was completed in 68 ± 14 sec following termination of exercise, and stress perfusion CMR was completed in 88 ± 8 sec. Agreement between SPECT and CMR was moderate (κ = 0.58). Accuracy in eight patients who underwent coronary angiography was 7/8 for CMR and 5/8 for SPECT (p = 0.625). Follow-up at 6 months indicated freedom from cardiovascular events in 29/29 CMR-negative and 33/34 SPECT-negative patients. Conclusions Exercise stress CMR including wall motion and perfusion is feasible in patients with suspected ischemic heart disease. Larger clinical trials are warranted based on the promising results of this pilot study to allow comparative effectiveness studies of this stress imaging system vs. other stress imaging modalities. PMID:20624294

  8. Use of the cavity-to-myocardial count ratio with Tc-99m sestamibi myocardial perfusion SPECT to predict reduced left ventricular function

    SciTech Connect

    Heerden, B.B. van; Heerden, P.D.R. van; Wasserman, H.J.

    1994-05-01

    In patients with left ventricular dysfunction, the left ventricular cavity appears abnormally photopenic on SPECT images, both with T1-201 and Tc-99m sestamibi showed a linear correlation between the cavity-to-myocardial count ratio (C/M ratio) and left ventricular ejection fraction (LVEF) with T1-201 SPECT. Using an exercise ratio of 0.4 as the lower limit of normal, they could predict a reduced LVEF with a sensitivity of 83% and specificity of 78%. The purpose of our study was to ascertain whether the C/M ratio could also be used as an indicator of LVEF when using Tc-99m sestamibi as imaging agent.

  9. Prediction of multivessel coronary artery disease and prognosis early after acute myocardial infarction by exercise electrocardiography and thallium-201 myocardial perfusion scanning

    SciTech Connect

    Abraham, R.D.; Freedman, S.B.; Dunn, R.F.; Newman, H.; Roubin, G.S.; Harris, P.J.; Kelly, D.T.

    1986-09-01

    Exercise electrocardiography and thallium scanning were performed a mean of 24 days after uncomplicated acute myocardial infarction in 103 patients, aged 36 to 60 years, who also underwent coronary angiography. The purpose of the study was to determine the ability of the noninvasive tests to predict multivessel coronary artery disease (CAD) and prognosis. Patients were followed up to document medical complications (incidence 12%: 3 deaths, 1 resuscitated cardiac arrest, 4 recurrent infarctions, 4 admissions with unstable angina) and combined events (medical events or bypass surgery, incidence 23%). The sensitivity, specificity and predictive accuracy for predicting multivessel CAD were 64%, 77% and 64% for a positive exercise electrocardiographic (ECG) response, 64%, 88% and 80% for a remote thallium defect, and 42%, 96% and 88% for a combination of the 2 tests. With 2 tests yielding negative findings the probability of multivessel CAD was 13%. No variable (positive exercise ECG response, remote thallium defect and presence of multivessel CAD) predicted medical events, although there were nonsignificant trends to more events in patients with any of those findings. The relative risk of combined events was 2.5 (p less than 0.05) for a positive exercise ECG response; 1.8 (NS) for a remote thallium defect; 2.6 (p less than 0.05) for multivessel CAD; and 3.1 (p less than 0.025) for both positive ECG response and remote defect. A combination of exercise electrocardiography and thallium scanning early after acute myocardial infarction helps to identify subsets of patients with high and low probabilities of multivessel CAD and combined medical or surgical events.

  10. Safety of guidewire-based measurement of fractional flow reserve and the index of microvascular resistance using intravenous adenosine in patients with acute or recent myocardial infarction

    PubMed Central

    Ahmed, Nadeem; Layland, Jamie; Carrick, David; Petrie, Mark C.; McEntegart, Margaret; Eteiba, Hany; Hood, Stuart; Lindsay, Mitchell; Watkins, Stuart; Davie, Andrew; Mahrous, Ahmed; Carberry, Jaclyn; Teng, Vannesa; McConnachie, Alex; Curzen, Nick; Oldroyd, Keith G.; Berry, Colin

    2016-01-01

    Aims Coronary guidewire-based diagnostic assessments with hyperemia may cause iatrogenic complications. We assessed the safety of guidewire-based measurement of coronary physiology, using intravenous adenosine, in patients with an acute coronary syndrome. Methods We prospectively enrolled invasively managed STEMI and NSTEMI patients in two simultaneously conducted studies in 6 centers (NCT01764334; NCT02072850). All of the participants underwent a diagnostic coronary guidewire study using intravenous adenosine (140 μg/kg/min) infusion for 1–2 min. The patients were prospectively assessed for the occurrence of serious adverse events (SAEs) and symptoms and invasively measured hemodynamics were also recorded. Results 648 patients (n = 298 STEMI patients in 1 hospital; mean time to reperfusion 253 min; n = 350 NSTEMI in 6 hospitals; median time to angiography from index chest pain episode 3 (2, 5) days) were included between March 2011 and May 2013. Two NSTEMI patients (0.3% overall) experienced a coronary dissection related to the guidewire. No guidewire dissections occurred in the STEMI patients. Chest symptoms were reported in the majority (86%) of patient's symptoms during the adenosine infusion. No serious adverse events occurred during infusion of adenosine and all of the symptoms resolved after the infusion ceased. Conclusions In this multicenter analysis, guidewire-based measurement of FFR and IMR using intravenous adenosine was safe in patients following STEMI or NSTEMI. Self-limiting symptoms were common but not associated with serious adverse events. Finally, coronary dissection in STEMI and NSTEMI patients was noted to be a rare phenomenon. PMID:26418191

  11. 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.

  12. Prognostic Value of Major Cardiac Event Risk Score Estimated With Gated Myocardial Perfusion Imaging in Japanese Patients With Coronary Artery Disease.

    PubMed

    Yoda, Shunichi; Nakanishi, Kanae; Tano, Ayako; Hori, Yusuke; Hayase, Misa; Mineki, Takashi; Suzuki, Yasuyuki; Matsumoto, Naoya; Hirayama, Atsushi

    2016-07-27

    We published a cardiac event risk score (CERS) predicting the risk of major cardiac events (MCEs) within 3 years. The purpose of this study was to verify the prognostic value of the CERS before and after treatment in Japanese patients with coronary artery disease.We retrospectively investigated 612 patients who underwent rest (201)Tl and stress (99m)Tc-tetrofosmin myocardial perfusion single photon emission computed tomography (SPECT) between October 2004 and March 2013 and who had a significant stenosis with ≥ 75% narrowing of the arterial diameter detected by coronary angiography performed after confirmation of ≥ 5% ischemia with the SPECT. The patients underwent treatment including revascularization and medication, and thereafter, were re-evaluated with SPECT during a chronic phase and followed-up to confirm prognosis for ≥ 1 year. The endpoint was the onset of MCEs during the follow-up.During the follow-up (36.7 ± 14.5 months), 50 patients (8.7%) experienced MCEs comprising cardiac death (n = 16), non-fatal myocardial infarction (n = 4), and unstable angina pectoris (n = 30). The multivariate Cox proportional hazards regression model analysis for the actual occurrence of MCEs showed the summed difference score % and MCE risks estimated with the CERS after treatment to be significant independent variables. Ischemic reduction after treatment contributed significantly to a decrease in the MCE risks. The MCE risks estimated with the CERS after treatment were generally consistent with the incidence of the MCEs actually observed.The CERS after treatment is a valuable formula for predicting prognosis in Japanese patients with coronary artery disease. PMID:27357436

  13. Coronary vascular resistance increases under full bypass support of centrifugal pumps--relation between myocardial perfusion and ventricular workload during pump support.

    PubMed

    Ando, Masahiko; Takewa, Yoshiaki; Nishimura, Takashi; Yamazaki, Kenji; Kyo, Shunei; Ono, Minoru; Tsukiya, Tomonori; Mizuno, Toshihide; Taenaka, Yoshiyuki; Tatsumi, Eisuke

    2012-01-01

    Coronary circulation is closely linked to myocardial oxygen consumption (MVO(2)), and previous reports have suggested decreased coronary flow (CoF) under left ventricular assist device support. Decreased CoF itself under support is not unfavorable because the native heart can be well unloaded and myocardial oxygen demand is also decreased. There should be an autoregulatory system that would maintain optimal CoF according to oxygen demand; however, the detailed mechanism is still unclear. The aim of the current study is to evaluate the effect of centrifugal pumps on CoF under varied bypass rates in relation to left ventricle workload. A centrifugal pump, EVAHEART (Sun Medical Technology Research Corporation, Nagano, Japan), was installed in an adult goat (n = 10, 61.3 ± 6.5 kg). We set up the following conditions, including Circuit-Clamp (i.e., no pump support), 50% bypass, and 100% bypass. In these settings, CoF, MVO(2), pressure-volume area (PVA), and coronary vascular resistance (CVR) were measured. In 100% bypass, CoF, MVO(2), and PVA were all decreased significantly from clamp. While in 50% bypass, CoF and MVO(2) decreased from clamp, but not PVA. There was a significant 40% increase in CVR in 100% bypass from clamp. This CVR increase in 100% bypass was possibly due to mechanical collapse of coronary vascular bed itself by pump support or increased vascular tone through autoregulatory system. In clinical settings, we should adjust optimal pump speed so as not to cause this vascular collapse. However, to clarify autoregulatory system of the coronary perfusion, further investigation is ongoing in ischemic and heart failure models. PMID:21848933

  14. Cardiac effects of the extract and active components of radix stephaniae tetrandrae. II. Myocardial infarct, arrhythmias, coronary arterial flow and heart rate in the isolated perfused rat heart.

    PubMed

    Yu, X C; Wu, S; Wang, G Y; Shan, J; Wong, T M; Chen, C F; Pang, K T

    2001-05-11

    The primary purpose of the present study was to compare the cardioprotective effects of the extract from radix stephaniae tetrandrae (RST) and its individual compounds, tetrandrine (Tet) and fanchinoline (Fan). Secondly, we also compared the cardiac effects of the individual compounds and the RST extract with those of verapamil, a classical Ca2+ channel blocker. The Langendorff isolated perfused rat heart preparation was used. Regional ischaemia and reperfusion was employed to induce myocardial infarct and arrhythmia. Infarct, arrhythmia, heart rate and coronary artery flow were determined in hearts treated with vehicle, RST extract, Tet, Fan, or verapamil. It was found that RST extract, of which only 9% was Tet, and Tet alone produced equally potent ameliorating effects on arrhythmia and infarct induced by ischaemia and reperfusion without further inhibiting ischaemia-reduced heart rate and coronary artery flow. Fan had no effects on arrhythmia and infarct induced by ischaemia and reperfusion; but it induced S-T segment elevation and further reduced heart rate and coronary artery flow during ischaemia. Verapamil also ameliorated the effects of ischaemia and reperfusion on arrhythmia and infarct. It should be noted that 1 microM verapamil, that produced comparable effects on infarct and arrhythmia to the RST extract and Tet, further inhibited heart rate during ischaemia. The results indicate that the RST extract produces equally potent cardioprotective and anti-arrhythmic effects as Tet alone. Both RST extract and Tet may be better choices for the treatment of arrhythmia and infarct induced by myocardial ischaemia and reperfusion than the classical Ca2+ channel blocker, verapamil as they do not further reduce heart rate during ischaemia. PMID:11432452

  15. The role of adenosine in functional hyperaemia in the coronary circulation of anaesthetized dogs.

    PubMed Central

    Karim, F; Goonewardene, I P

    1996-01-01

    1. The aim of this investigation was to determine the contribution of adenosine to coronary active hyperaemia in the dog denervated heart by using adenosine deaminase. 2. Beagles were anaesthetized with thiopentone sodium (500 mg, I.V.) and chloralose (100 mg kg-1, LV.) and artificially ventilated. The hearts were denervate by bilateral cervical vagotomy and cardiac sympathectomy. Blood samples were collected from the coronary sinus via a cannula passed through the right external jugular vein. The anterior descending or circumflex branch of the left coronary artery was cannulated and perfused with blood from the left subclavian artery under systemic blood pressure through an electromagnetic flow probe and a perfusion circuit. The heart was paced (3 V, 0.2 ms and a suitable frequency) via two electrodes attached to the right atrium from 109 +/- 7.3 to 170 +/- 9.8 beats min-4 (means +/- S.E.M.) for 3-4 min, first during an infusion of the solvent, and then during an infusion of a solution of adenosine deaminase (5 U kg-1 min-1) into the circuit. 3. In seventeen tests in eight dogs, infusion of adenosine deaminase did not cause a significant change in the basal coronary blood flow nor in the immediate increase (within 10s) in blood flow induced by pacing the heart from its basal rate to 170 beats min-1. However, adenosine deaminase did cause a significant attenuation by 58 +/- 5.2% (P < 0.05) of the increase in coronary blood flow induced at 3-4 min of pacing from 31 +/- 4.6 to 43 +/- 5.8 ml min-1 (100 g cardiac tissue)-1. Concomitantly, the pacing-induced increase in coronary vascular conductance (from 0.41 +/- 0.08 to 0.54 +/- 0.12 ml min-1 (100 g)-1 mmHg-1) was reduced by 75 +/- 6.6% (P < 0.02) and the increase in myocardial O2 consumption (from 13 +/- 3.5 to 21 +/- 4.2 ml min-1 (100 g)-1) was reduced by 50 +/- 12% (P < 0.05) but without significant changes in oxygen extraction or myocardial contractility. 4. The results show that although adenosine is unlikely to

  16. Collimator optimization and collimator-detector response compensation in myocardial perfusion SPECT using the ideal observer with and without model mismatch and an anthropomorphic model observer

    NASA Astrophysics Data System (ADS)

    Ghaly, Michael; Links, Jonathan M.; Frey, Eric C.

    2016-03-01

    The collimator is the primary factor that determines the spatial resolution and noise tradeoff in myocardial perfusion SPECT images. In this paper, the goal was to find the collimator that optimizes the image quality in terms of a perfusion defect detection task. Since the optimal collimator could depend on the level of approximation of the collimator-detector response (CDR) compensation modeled in reconstruction, we performed this optimization for the cases of modeling the full CDR (including geometric, septal penetration and septal scatter responses), the geometric CDR, or no model of the CDR. We evaluated the performance on the detection task using three model observers. Two observers operated on data in the projection domain: the Ideal Observer (IO) and IO with Model-Mismatch (IO-MM). The third observer was an anthropomorphic Channelized Hotelling Observer (CHO), which operated on reconstructed images. The projection-domain observers have the advantage that they are computationally less intensive. The IO has perfect knowledge of the image formation process, i.e. it has a perfect model of the CDR. The IO-MM takes into account the mismatch between the true (complete and accurate) model and an approximate model, e.g. one that might be used in reconstruction. We evaluated the utility of these projection domain observers in optimizing instrumentation parameters. We investigated a family of 8 parallel-hole collimators, spanning a wide range of resolution and sensitivity tradeoffs, using a population of simulated projection (for the IO and IO-MM) and reconstructed (for the CHO) images that included background variability. We simulated anterolateral and inferior perfusion defects with variable extents and severities. The area under the ROC curve was estimated from the IO, IO-MM, and CHO test statistics and served as the figure-of-merit. The optimal collimator for the IO had a resolution of 9-11 mm FWHM at 10 cm, which is poorer resolution than typical collimators

  17. Collimator optimization and collimator-detector response compensation in myocardial perfusion SPECT using the ideal observer with and without model mismatch and an anthropomorphic model observer.

    PubMed

    Ghaly, Michael; Links, Jonathan M; Frey, Eric C

    2016-03-01

    The collimator is the primary factor that determines the spatial resolution and noise tradeoff in myocardial perfusion SPECT images. In this paper, the goal was to find the collimator that optimizes the image quality in terms of a perfusion defect detection task. Since the optimal collimator could depend on the level of approximation of the collimator-detector response (CDR) compensation modeled in reconstruction, we performed this optimization for the cases of modeling the full CDR (including geometric, septal penetration and septal scatter responses), the geometric CDR, or no model of the CDR. We evaluated the performance on the detection task using three model observers. Two observers operated on data in the projection domain: the Ideal Observer (IO) and IO with Model-Mismatch (IO-MM). The third observer was an anthropomorphic Channelized Hotelling Observer (CHO), which operated on reconstructed images. The projection-domain observers have the advantage that they are computationally less intensive. The IO has perfect knowledge of the image formation process, i.e. it has a perfect model of the CDR. The IO-MM takes into account the mismatch between the true (complete and accurate) model and an approximate model, e.g. one that might be used in reconstruction. We evaluated the utility of these projection domain observers in optimizing instrumentation parameters. We investigated a family of 8 parallel-hole collimators, spanning a wide range of resolution and sensitivity tradeoffs, using a population of simulated projection (for the IO and IO-MM) and reconstructed (for the CHO) images that included background variability. We simulated anterolateral and inferior perfusion defects with variable extents and severities. The area under the ROC curve was estimated from the IO, IO-MM, and CHO test statistics and served as the figure-of-merit. The optimal collimator for the IO had a resolution of 9-11 mm FWHM at 10 cm, which is poorer resolution than typical collimators

  18. Cardiac perfusion imaging using hyperpolarized 13c urea using flow sensitizing gradients

    PubMed Central

    Miller, Jack J.; Robson, Matthew D.; Tyler, Damian J.

    2015-01-01

    Purpose To demonstrate the feasibility of imaging the first passage of a bolus of hyperpolarized 13C urea through the rodent heart using flow‐sensitizing gradients to reduce signal from the blood pool. Methods A flow‐sensitizing bipolar gradient was optimized to reduce the bright signal within the cardiac chambers, enabling improved contrast of the agent within the tissue capillary bed. The gradient was incorporated into a dynamic golden angle spiral 13C imaging sequence. Healthy rats were scanned during rest (n = 3) and under adenosine stress‐induced hyperemia (n = 3). Results A two‐fold increase in myocardial perfusion relative to rest was detected during adenosine stress‐induced hyperemia, consistent with a myocardial perfusion reserve of two in rodents. Conclusion The new pulse sequence was used to obtain dynamic images of the first passage of hyperpolarized 13C urea in the rodent heart, without contamination from bright signal within the neighboring cardiac lumen. This probe of myocardial perfusion is expected to enable new hyperpolarized 13C studies in which the cardiac metabolism/perfusion mismatch can be identified. Magn Reson Med, 2015. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Magn Reson Med 75:1474–1483, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance. PMID:25991580

  19. Prognostic value of normal regadenoson stress perfusion cardiovascular magnetic resonance

    PubMed Central

    2013-01-01

    Background Regadenoson is a vasodilator stress agent that selectively activates the A2A receptor. Compared to adenosine, regadenoson is easier to administer and results in fewer side effects. Although extensively studied in patients undergoing nuclear perfusion imaging (MPI), its use for perfusion cardiovascular magnetic resonance (CMR) is not well described. The aim of this study was to determine the prognostic value of a normal regadenoson perfusion CMR in patients with known or suspected coronary artery disease. Methods Patients with known or suspected coronary artery disease were prospectively enrolled to receive perfusion CMR (Philips 1.5 T) with regadenoson. Three short-axis slices of the left ventricle (LV) were obtained during first pass of contrast using a hybrid GRE-EPI pulse sequence (0.075 mmol/kg Gadolinium-DTPA-BMA at 4 ml/sec). Imaging was performed 1 minute after injection of regadenoson (0.4 mg) and repeated 15 minutes after reversal of hyperemia with aminophylline (125 mg). Perfusion defects were documented if they persisted for ≥2 frames after peak enhancement of the LV cavity. CMR was considered abnormal if there was a resting wall motion abnormality, decreased LVEF (<40%), presence of LGE, or the presence of a perfusion defect during hyperemia. All patients were followed for a minimum of 1 year for major adverse cardiovascular event (MACE) defined as coronary revascularization, non-fatal myocardial infarction, and cardiovascular death. Results 149 patients were included in the final analysis. Perfusion defects were noted in 43/149 (29%) patients; 59/149 (40%) had any abnormality on CMR. During the mean follow-up period of 24 ± 9 months, 17/149 (11.4%) patients experienced MACE. The separation in the survival distributions for those with perfusion defects and those without perfusion defects was highly significant (log-rank p = 0.0001). When the absence of perfusion defects was added to the absence of other resting CMR

  20. Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study

    NASA Astrophysics Data System (ADS)

    Lee, Taek-Soo; Higuchi, Takahiro; Lautamäki, Riikka; Bengel, Frank M.; Tsui, Benjamin M. W.

    2015-09-01

    We evaluated the performance of a new 4D image reconstruction method for improved 4D gated myocardial perfusion (MP) SPECT using a task-based human observer study. We used a realistic 4D NURBS-based Cardiac-Torso (NCAT) phantom that models cardiac beating motion. Half of the population was normal; the other half had a regional hypokinetic wall motion abnormality. Noise-free and noisy projection data with 16 gates/cardiac cycle were generated using an analytical projector that included the effects of attenuation, collimator-detector response, and scatter (ADS), and were reconstructed using the 3D FBP without and 3D OS-EM with ADS corrections followed by different cut-off frequencies of a 4D linear post-filter. A 4D iterative maximum a posteriori rescaled-block (MAP-RBI)-EM image reconstruction method with ADS corrections was also used to reconstruct the projection data using various values of the weighting factor for its prior. The trade-offs between bias and noise were represented by the normalized mean squared error (NMSE) and averaged normalized standard deviation (NSDav), respectively. They were used to select reasonable ranges of the reconstructed images for use in a human observer study. The observers were trained with the simulated cine images and were instructed to rate their confidence on the absence or presence of a motion defect on a continuous scale. We then applied receiver operating characteristic (ROC) analysis and used the area under the ROC curve (AUC) index. The results showed that significant differences in detection performance among the different NMSE-NSDav combinations were found and the optimal trade-off from optimized reconstruction parameters corresponded to a maximum AUC value. The 4D MAP-RBI-EM with ADS correction, which had the best trade-off among the tested reconstruction methods, also had the highest AUC value, resulting in significantly better human observer detection performance when detecting regional myocardial wall motion

  1. Task-Based Evaluation of a 4D MAP-RBI-EM Image Reconstruction Method for Gated Myocardial Perfusion SPECT using a Human Observer Study

    PubMed Central

    Lee, Taek-Soo; Higuchi, Takahiro; Lautamäki, Riikka; Bengel, Frank M.; Tsui, Benjamin M. W.

    2015-01-01

    We evaluated the performance of a new 4D image reconstruction method for improved 4D gated myocardial perfusion (MP) SPECT using a task-based human observer study. We used a realistic 4D NURBS-based Cardiac-Torso (NCAT) phantom that models cardiac beating motion. Half of the population was normal; the other half had a regional hypokinetic wall motion abnormality. Noise-free and noisy projection data with 16 gates/cardiac cycle were generated using an analytical projector that included the effects of attenuation, collimator-detector response, and scatter (ADS), and were reconstructed using the 3D FBP without and 3D OS-EM with ADS corrections followed by different cut-off frequencies of a 4D linear post-filter. A 4D iterative maximum a posteriori rescaled-block (MAP-RBI)-EM image reconstruction method with ADS corrections was also used to reconstruct the projection data using various values of the weighting factor for its prior. The trade-offs between bias and noise were represented by the normalized mean squared error (NMSE) and averaged normalized standard deviation (NSDav), respectively. They were used to select reasonable ranges of the reconstructed images for use in a human observer study. The observers were trained with the simulated cine images and were instructed to rate their confidence on the absence or presence of a motion defect on a continuous scale. We then applied receiver operating characteristic (ROC) analysis and used the area under the ROC curve (AUC) index. The results showed that significant differences in detection performance among the different NMSE-NSDav combinations were found and the optimal trade-off from optimized reconstruction parameters corresponded to a maximum AUC value. The 4D MAP-RBI-EM with ADS correction, which had the best trade-off among the tested reconstruction methods, also had the highest AUC value, resulting in significantly better human observer detection performance when detecting regional myocardial wall motion

  2. Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study.

    PubMed

    Lee, Taek-Soo; Higuchi, Takahiro; Lautamäki, Riikka; Bengel, Frank M; Tsui, Benjamin M W

    2015-09-01

    We evaluated the performance of a new 4D image reconstruction method for improved 4D gated myocardial perfusion (MP) SPECT using a task-based human observer study. We used a realistic 4D NURBS-based Cardiac-Torso (NCAT) phantom that models cardiac beating motion. Half of the population was normal; the other half had a regional hypokinetic wall motion abnormality. Noise-free and noisy projection data with 16 gates/cardiac cycle were generated using an analytical projector that included the effects of attenuation, collimator-detector response, and scatter (ADS), and were reconstructed using the 3D FBP without and 3D OS-EM with ADS corrections followed by different cut-off frequencies of a 4D linear post-filter. A 4D iterative maximum a posteriori rescaled-block (MAP-RBI)-EM image reconstruction method with ADS corrections was also used to reconstruct the projection data using various values of the weighting factor for its prior. The trade-offs between bias and noise were represented by the normalized mean squared error (NMSE) and averaged normalized standard deviation (NSDav), respectively. They were used to select reasonable ranges of the reconstructed images for use in a human observer study. The observers were trained with the simulated cine images and were instructed to rate their confidence on the absence or presence of a motion defect on a continuous scale. We then applied receiver operating characteristic (ROC) analysis and used the area under the ROC curve (AUC) index. The results showed that significant differences in detection performance among the different NMSE-NSDav combinations were found and the optimal trade-off from optimized reconstruction parameters corresponded to a maximum AUC value. The 4D MAP-RBI-EM with ADS correction, which had the best trade-off among the tested reconstruction methods, also had the highest AUC value, resulting in significantly better human observer detection performance when detecting regional myocardial wall motion

  3. Nucleoside transporter expression and adenosine uptake in the rat cochlea.

    PubMed

    Khan, Abdul F; Thorne, Peter R; Muñoz, David J B; Wang, Carol J H; Housley, Gary D; Vlajkovic, Srdjan M

    2007-02-12

    Even though extracellular adenosine plays multiple roles in the cochlea, the mechanisms that control extracellular adenosine concentrations in this organ are unclear. This study investigated the expression of nucleoside transporters and adenosine uptake in the rat cochlea. Reverse transcription-polymerase chain reaction revealed the expression of mRNA transcripts for two equilibrative (ENT1 and ENT2) and two concentrative (CNT1 and CNT2) nucleoside transporters. Exogenous adenosine perfused through the cochlear perilymphatic compartment was taken up by cells lining the compartment. Adenosine uptake was sensitive to changes in extracellular Na concentrations and inhibited by nitrobenzylthioinosine (an adenosine uptake blocker). The study suggests that the bi-directional nucleoside transport supports the uptake and recycling of purines and regulates the activation of adenosine receptors by altering adenosine concentrations in cochlear fluid spaces. PMID:17314663

  4. Characterization of the H+ Translocating Adenosine Triphosphatase and Pyrophosphatase of Vacuolar Membranes Isolated by Means of a Perfusion Technique from Chara corallina1

    PubMed Central

    Takeshige, Kazuhiko; Tazawa, Masashi; Hager, Achim

    1988-01-01

    Sealed tonoplast vesicles were isolated from single cells of Chara corallina with the aid of an intracellular perfusion technique in combination with a 3/10% Percoll two step gradient centrifugation. The isolated tonoplast fraction was free from plasmalemma and chloroplasts, and showed no activities of cytochrome c oxidase, and latent IDPase, but had about 10% of the NADH-cytochrome c reductase activity. The vesicles had both ATPase and PPase activities, which could be stimulated in the presence of 10 micromolar gramicidin by 170 and 130%, respectively, demonstrating the existence of sealed vesicles. Furthermore, ATP- and PPi-dependent H+ pumping through the membrane into the vesicles was shown. Both ATPase and PPase had pH optima around pH 8.5. At the physiological pH, 7.3, they still had more than 80% of their maximal activities. Ammonium molybdate, azide, and vanadate had no or little effect on the activities of both enzymes or their associated H+ pumping activities. N,N′-dicyclohexylcarbodiimide inhibited the ATPase strongly (I50 = 20 micromolar) but the PPase only weakly. The ATPase was also more sensitive to N-ethylmaleimide than the PPase. 4,4′-Stilbenedisulfonic acid affected both enzyme activities and their associated H+ pumping activities. This is in contrast to the H+-PPase of higher plants which is 4,4′-stilbenedisulfonic acid insensitive. PMID:16666049

  5. The predictive value of chronic kidney disease for assessing cardiovascular events under consideration of pretest probability for coronary artery disease in patients who underwent stress myocardial perfusion imaging.

    PubMed

    Furuhashi, Tatsuhiko; Moroi, Masao; Joki, Nobuhiko; Hase, Hiroki; Masai, Hirofumi; Kunimasa, Taeko; Fukuda, Hiroshi; Sugi, Kaoru

    2013-02-01

    Pretest probability of coronary artery disease (CAD) facilitates diagnosis and risk stratification of CAD. Stress myocardial perfusion imaging (MPI) and chronic kidney disease (CKD) are established major predictors of cardiovascular events. However, the role of CKD to assess pretest probability of CAD has been unclear. This study evaluates the role of CKD to assess the predictive value of cardiovascular events under consideration of pretest probability in patients who underwent stress MPI. Patients with no history of CAD underwent stress MPI (n = 310; male = 166; age = 70; CKD = 111; low/intermediate/high pretest probability = 17/194/99) and were followed for 24 months. Cardiovascular events included cardiac death and nonfatal acute coronary syndrome. Cardiovascular events occurred in 15 of the 310 patients (4.8 %), but not in those with low pretest probability which included 2 CKD patients. In patients with intermediate to high pretest probability (n = 293), multivariate Cox regression analysis identified only CKD [hazard ratio (HR) = 4.88; P = 0.022) and summed stress score of stress MPI (HR = 1.50; P < 0.001) as independent and significant predictors of cardiovascular events. Cardiovascular events were not observed in patients with low pretest probability. In patients with intermediate to high pretest probability, CKD and stress MPI are independent predictors of cardiovascular events considering the pretest probability of CAD in patients with no history of CAD. In assessing pretest probability of CAD, CKD might be an important factor for assessing future cardiovascular prognosis. PMID:22806318

  6. Diagnostic value of a new myocardial perfusion agent, teboroxime (SQ 30,217), utilizing a rapid planar imaging protocol: Preliminary results

    SciTech Connect

    Hendel, R.C.; McSherry, B.; Karimeddini, M.; Leppo, J.A. )

    1990-10-01

    Technetium-99m-labeled agents have advantages over thallium-201 in terms of photon statistics, cost and clinical availability. They have been suggested as an alternative to thallium for myocardial perfusion imaging. Teboroxime is a new boronic acid adduct of technetium dioxime (BATO) compound that demonstrates favorable characteristics in preliminary studies. With use of a novel (seated) patient positioning technique and a rapid dynamic acquisition protocol, 30 patients underwent planar imaging with teboroxime while at rest and after maximal treadmill exercise. Postexercise scans were completed in an average time (mean +/- SD) of 4.4 +/- 1.6 min, with 4.8 +/- 1.5 min for the views at rest. These results were compared with coronary arteriography or thallium scintigraphy after treadmill exercise, or both. Diagnostic agreement (abnormal versus normal) was present in 28 of the 30 patients (p less than 0.001). Regarding physiologic assessment as compared with thallium scintigraphy, the finding of infarction and ischemia was concordant in 89% and 86% of patients, respectively. This report describes the initial use of teboroxime with a rapid dynamic planar imaging technique, resulting in a high correlation with exercise thallium scintigraphy. Delayed postexercise images obtained 5 to 10 min after exercise demonstrated rapid disappearance of exercise-induced defects noted on the initial (0 to 5 min) postexercise views. The rapid differential washout with teboroxime has not been previously described and the possible clinical significance is discussed.

  7. Diagnostic value of a new myocardial perfusion agent, teboroxime (SO 30,217), utilizing a rapid planar imaging protocol: Preliminary results

    SciTech Connect

    Hendel, R.C.; McSherry, B.; Karimeddini, M.; Leppo, J.A. )

    1990-11-01

    Technetium-99m-labeled agents have advantages over thallium-201 in terms of photon statistics, cost and clinical availability. They have been suggested as an alternative to thallium for myocardial perfusion imaging. Teboroxime is a new boronic acid adduct of technetium dioxime (BATO) compound that demonstrates favorable characteristics in preliminary studies. With use of a novel (seated) patient positioning technique and a rapid dynamic acquisition protocol, 30 patients underwent planar imaging with teboroxoime while at rest and after maximal treadmill exercise. Postexercise scans were completed in an average time (mean +/- SD) of 4.4 +/- 1.6 min, with 4.8 +/- 1.5 min for the views at rest. These results were compared with coronary arteriography or thallium scintigraphy after treadmill exercise, or both. Diagnostic agreement (abnormal versus normal) was present in 28 of the 30 patients (p less than 0.001). Regarding physiologic assessment as compared with thallium scintigraphy, the finding of infarction and ischemia was concordant in 89% and 86% of patients, respectively. This report describes the initial use of teboroxime with a rapid dynamic planar imaging technique, resulting in a high correlation with exercise thallium scintigraphy. Delayed postexercise images obtained 5 to 10 min after exercise demonstrated rapid disappearance of exercise-induced defects noted on the initial (0 to 5 min) postexercise views. The rapid differential washout with teboroxime has not been previously described and the possible clinical significance is discussed.

  8. The Concordance between Myocardial Perfusion Imaging and Coronary Angiography in Detecting Coronary Artery Disease: A Retrospective Study in a Tertiary Cardiac Center at King Abdullah Medical City

    PubMed Central

    Aboul-Enein, Fatma; Alharthi, Hail T.

    2016-01-01

    Background. Coronary artery disease (CAD) is considered as the leading cause of the cardiovascular fatalities worldwide. CAD is diagnosed by many modalities of imaging such as myocardial perfusion imaging (MPI) and coronary angiography (CAG). Methods. A retrospective cross-sectional study was conducted that included all patients referred to the KAMC (King Abdullah Medical City) nuclear cardiology lab from its opening until the end of May 2014 (a period of 17 months). A total of 228 patient reports with a history of conducting either CAG or MPI or both were used in this study and statistically analyzed. Results. An analysis of the MPI results revealed that 78.5% of the samples were abnormal. On the other hand, 26.75% of the samples revealed that they were subjected to CAG and MPI. There was a significant and fair agreement between MPI and CAG by using all the agreement coefficients (kappa = 0.237, phi = 0.310, and P value = 0.043). The sensitivity, specificity, and accuracy of MPI with reference to CAG were 97.8%, 20%, and 78.69%, respectively. In addition, positive predictive and negative predictive values were 78.95% and 75%, respectively. Conclusion. In a tertiary referral center, there was a significant agreement between MPI and CAG and a high accuracy of MPI. MPI was a noninvasive diagnostic test that could be used as a gatekeeper for CAG. PMID:27429833

  9. Caffeine reduces the sensitivity of vasodilator MPI for the detection of myocardial ischaemia: Pro.

    PubMed

    Reyes, Eliana

    2016-06-01

    Caffeine is a non-selective antagonist at the adenosine receptors, which is expected to reverse both the intended (coronary vasodilation) and unintended (hypotension, flushing) effects of exogenously administered adenosine and adenosine-related compounds. In the past, several studies were conducted to characterize the effect of caffeine on vasodilator myocardial perfusion imaging (MPI) with conflicting results. However, new evidence supports earlier observations and shows that recent caffeine intake attenuates vasodilator-induced myocardial hyperaemia and may therefore reduce the sensitivity of radionuclide MPI for the detection of inducible perfusion abnormality in patients with coronary artery disease. Although the magnitude of this effect and hence its clinical significance are dose dependent, the acute response to equivalent doses of caffeine varies largely among individuals, and this might be explained by differences in caffeine exposure and genetically determined variations in caffeine metabolism. Abstinence from caffeinated foods and beverages for a minimum of 12 hours before vasodilator stress is therefore recommended although longer abstention might be required in order to prevent the potentially blocking effect of residual caffeine on vasodilator-mediated actions. PMID:26883776

  10. Adenosine transporters.

    PubMed

    Thorn, J A; Jarvis, S M

    1996-06-01

    1. In mammals, nucleoside transport is an important determinant of the pharmacokinetics, plasma and tissue concentration, disposition and in vivo biological activity of adenosine as well as nucleoside analogues used in antiviral and anticancer therapies. 2. Two broad types of adenosine transporter exist, facilitated-diffusion carriers and active processes driven by the transmembrane sodium gradient. 3. Facilitated-diffusion adenosine carriers may be sensitive (es) or insensitive (ei) to nanomolar concentrations of the transport inhibitor nitrobenzylthioinosine (NBMPR). Dipyridamole, dilazep and lidoflazine analogues are also more potent inhibitors of the es carrier than the ei transporter in cells other than those derived from rat tissues. 4. The es transporter has a broad substrate specificity (apparent Km for adenosine approximately 25 microM in many cells at 25 degrees C), is a glycoprotein with an average apparent Mr of 57,000 in human erythrocytes that has been purified to near homogeneity and may exist in situ as a dimer. However, there is increasing evidence to suggest the presence of isoforms of the es transporter in different cells and species, based on kinetic and molecular properties. 5. The ei transporter also has a broad substrate specificity with a lower affinity for some nucleoside permeants than the es carrier, is genetically distinct from es but little information exists as to the molecular properties of the protein. 6. Sodium-dependent adenosine transport is present in many cell types and catalysed by four distinct systems, N1-N4, distinguished by substrate specificity, sodium coupling and tissue distribution. 7. Two genes have been identified which encode sodium-dependent adenosine transport proteins, SNST1 from the sodium/glucose cotransporter (SGLT1) gene family and the rat intestinal N2 transporter (cNT1) from a novel gene family including a bacterial nucleoside carrier (NupC). Transcripts of cNT1, which encodes a 648-residue protein, are

  11. Cardiovascular protection and antioxidant activity of the extracts from the mycelia of Cordyceps sinensis act partially via adenosine receptors.

    PubMed

    Yan, Xiao-Feng; Zhang, Zhong-Miao; Yao, Hong-Yi; Guan, Yan; Zhu, Jian-Ping; Zhang, Lin-Hui; Jia, Yong-Liang; Wang, Ru-Wei

    2013-11-01

    Mycelia of cultured Cordyceps sinensis (CS) is one of the most common substitutes for natural CS and was approved for arrhythmia in China. However, the role of CS in ameliorating injury during ischemia-reperfusion (I/R) is still unclear. We examined effects of extracts from CS on I/R and investigated the possible mechanisms. Post-ischemic coronary perfusion pressure, ventricular function, and coronary flow were measured using the Langendorff mouse heart model. Oxidative stress of cardiac homogenates was performed using an ELISA. Our results indicate that CS affords cardioprotection possibly through enhanced adenosine receptor activation. Cardioprotection was demonstrated by reduced post-ischemic diastolic dysfunction and improved recovery of pressure development and coronary flow. Treatment with CS largely abrogates oxidative stress and damage in glucose- or pyruvate-perfused hearts. Importantly, observed reductions in oxidative stress [glutathione disulfide (GSSG)]/[GSSG + glutathione] and [malondialdehyde (MDA)]/[superoxide dismutase + MDA] ratios as well as the resultant damage upon CS treatment correlate with functional markers of post-ischemic myocardial outcome. These effects of CS were partially blocked by 8-ρ-sulfophenyltheophylline, an adenosine receptor antagonist. Our results demonstrate a suppressive role of CS in ischemic contracture. Meanwhile, the results also suggest pre-ischemic adenosine receptor activation may be involved in reducing contracture in hearts pretreated with CS. PMID:23192916

  12. 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.

  13. 68GaTHM2BED: a potential generator-produced tracer of myocardial perfusion for positron emission tomography.

    PubMed

    Madsen, S L; Welch, M J; Motekaitis, R J; Martell, A E

    1992-05-01

    THM2BED [N,N,N',N'-tetrakis-(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine] is a new hexadentate ligand which has been synthesized and complexed with gallium isotopes. A conditional stability constant of 22.3 and a pM value of 20.7 have been determined for GaTHM2BED at physiological pH. Hexachelated and pentachelated complexes of GaTHM2BED have been isolated via preparatory HPLC and evaluated individually. The hexachelated isomer of 68GaTHM2BED clears slowly from the myocardium of rats and at 1 h post-injection the heart-to-blood ratio is 1.65. The data ratio indicates that this radiotracer may be capable of measuring blood flow in the heart. The ability of 68GaTHM2BED to delineate myocardial tissue in a dog has been evaluated and good images were obtained using hexachelated 68GaTHM2BED. There is evidence that this complex penetrates the blood-brain barrier. PMID:1526808

  14. Comparison of Gated SPECT Myocardial Perfusion Imaging with Echocardiography for the Measurement of Left Ventricular Volumes and Ejection Fraction in Patients With Severe Heart Failure

    PubMed Central

    Shojaeifard, Maryam; Ghaedian, Tahereh; Yaghoobi, Nahid; Malek, Hadi; Firoozabadi, Hasan; Bitarafan-Rajabi, Ahmad; Haghjoo, Majid; Amin, Ahmad; Azizian, Nasrin; Rastgou, Feridoon

    2015-01-01

    Background: Gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is known as a feasible tool for the measurement of left ventricular ejection fraction (EF) and volumes, which are of great importance in the management and follow-up of patients with coronary artery diseases. However, considering the technical shortcomings of SPECT in the presence of perfusion defect, the accuracy of this method in heart failure patients is still controversial. Objectives: The aim of the present study was to compare the results from gated SPECT MPI with those from echocardiography in heart failure patients to compare echocardiographically-derived left ventricular dimension and function data to those from gated SPECT MPI in heart failure patients. Patients and Methods: Forty-one patients with severely reduced left ventricular systolic function (EF ≤ 35%) who were referred for gated SPECT MPI were prospectively enrolled. Quantification of EF, end-diastolic volume (EDV), and end-systolic volume (ESV) was performed by using quantitative gated spect (QGS) (QGS, version 0.4, May 2009) and emory cardiac toolbox (ECTb) (ECTb, revision 1.0, copyright 2007) software packages. EF, EDV, and ESV were also measured with two-dimensional echocardiography within 3 days after MPI. Results: A good correlation was found between echocardiographically-derived EF, EDV, and ESV and the values derived using QGS (r = 0.67, r = 0.78, and r = 0.80 for EF, EDV, and ESV, respectively; P < 0.001) and ECTb (r = 0.68, 0.79, and r = 0.80 for EF, EDV, and ESV, respectively; P < 0.001). However, Bland-Altman plots indicated significantly different mean values for EF, 11.4 and 20.9 using QGS and ECTb, respectively, as compared with echocardiography. ECTb-derived EDV was also significantly higher than the EDV measured with echocardiography and QGS. The highest correlation between echocardiography and gated SPECT MPI was found for mean values of ESV different. Conclusions: Gated

  15. The Incremental Diagnostic Performance of Coronary Computed Tomography Angiography Added to Myocardial Perfusion Imaging in Patients with Intermediate-to-High Cardiovascular Risk

    PubMed Central

    Hsu, Pei-Ying; Lee, Wen-Jeng; Cheng, Mei-Fang; Yen, Ruoh-Fang; Tzen, Kai-Yuan; Wu, Yen-Wen

    2016-01-01

    Purpose Several studies have suggested that a combined approach of stress myocardial perfusion imaging (MPI) and coronary computed tomography angiography (CCTA) can provide diagnostic results with excellent accuracy. We aimed to explore whether the addition of CCTA to stress MPI provides incremental diagnostic value in intermediate-to-high cardiovascular risk patients. Methods A total of 106 consecutive patients (93 male, 65 ± 10.4 years) underwent coronary artery calcium scoring (CACS), CCTA and 201Thallium stress MPI before coronary angiography was reviewed. Thirty-seven patients (34.9%) had a history of proven coronary artery disease (CAD) or revascularization procedures, and four had documented non-significant CAD (3.8%). The remaining patients consisted of 17 (16.0%) classified as intermediate, and 48 (45.3%) as the high-risk groups. Results Obstructive CAD was diagnosed by invasive coronary angiography in 88 patients with 161 vessels. The sensitivity and specificity in a patient-based analysis for obstructive CAD were 99% and 17% for CCTA, 80% and 50% for MPI and 91% and 67% for the combined method, respectively. The per-vessel diagnostic sensitivity and specificity were 95% and 54% for CCTA, 59% and 75% for MPI and 84% and 76% for the combined method. There were significant differences (p < 0.05) when comparing the combined method with MPI or CCTA by areas under the curve in a patient- or vessel-based analysis. However, CACS of 400 or more could not further stratify the patients with obstructive CAD. Conclusions CCTA, not CACS, provided additional diagnostic values to stress MPI in patients with intermediate-to-high cardiovascular risk. PMID:27122945

  16. Left ventricular dyssynchrony assessed by two three-dimensional imaging modalities: phase analysis of gated myocardial perfusion SPECT and tri-plane tissue Doppler imaging

    PubMed Central

    Ajmone Marsan, Nina; Henneman, Maureen M.; Chen, Ji; Ypenburg, Claudia; Dibbets, Petra; Ghio, Stefano; Bleeker, Gabe B.; Stokkel, Marcel P.; van der Wall, Ernst E.; Tavazzi, Luigi; Garcia, Ernest V.

    2007-01-01

    Purpose To compare left ventricular (LV) dyssynchrony assessment by phase analysis from gated myocardial perfusion SPECT (GMPS) with LV dyssynchrony assessment by tri-plane tissue Doppler imaging (TDI). Baseline LV dyssynchrony assessed with standard deviation (SD) of time-to-peak systolic velocity of 12 LV segments (Ts-SD) with TDI has proven to be a powerful predictor of response to CRT. Information on LV dyssynchrony can also be provided by GMPS with phase analysis of regional LV maximal count changes throughout the cardiac cycle. Methods Forty heart failure patients, referred for evaluation of potential eligibility for CRT, underwent both 3D echocardiography, with tri-plane TDI, and resting GMPS. From tri-plane TDI, Ts-SD was used as a validated parameter of LV dyssynchrony and compared with different indices (histogram bandwidth, phase SD, histogram skewness and kurtosis) derived from phase analysis of GMPS. Results Histogram bandwidth and phase SD showed good correlation with Ts-SD (r=0.77 and r=0.74, p<0.0001, respectively). Patients with substantial LV dyssynchrony assessed with tri-plane TDI (Ts-SD ≥33 ms) had also significantly higher values of histogram bandwidth and phase SD. Conclusions The results of this study support the use of phase analysis by GMPS to evaluate LV dyssynchrony. Histogram bandwidth and phase SD showed the best correlation with Ts-SD assessed with tri-plane TDI and appeared the most optimal variables for assessment of LV dyssynchrony with GMPS. PMID:17874098

  17. Simultaneous Tc-99m/I-123 Dual Radionuclide Myocardial Perfusion/Innervation Imaging Using Siemens IQ-SPECT with SMARTZOOM Collimator

    PubMed Central

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric. C.

    2014-01-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region compared to a typical parallel-hole low-energy high-resolution collimator but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulation and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter modeling

  18. Simultaneous Tc-99m/I-123 dual-radionuclide myocardial perfusion/innervation imaging using Siemens IQ-SPECT with SMARTZOOM collimator

    NASA Astrophysics Data System (ADS)

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric C.

    2014-06-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region, compared to a typical parallel-hole low-energy high-resolution collimator, but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator-detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulations and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single-radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter

  19. Simultaneous Tc-99m/I-123 dual-radionuclide myocardial perfusion/innervation imaging using Siemens IQ-SPECT with SMARTZOOM collimator.

    PubMed

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric C

    2014-06-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region, compared to a typical parallel-hole low-energy high-resolution collimator, but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator-detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulations and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single-radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter

  20. Early experimental hypertension preserves the myocardial microvasculature but aggravates cardiac injury distal to chronic coronary artery obstruction.

    PubMed

    Urbieta Caceres, Victor Hugo; Lin, Jing; Zhu, Xiang-Yang; Favreau, Frederic D; Gibson, Matthew E; Crane, John A; Lerman, Amir; Lerman, Lilach O

    2011-02-01

    Coronary artery disease is a leading cause of death. Hypertension (HT) increases the incidence of cardiac events, but its effect on cardiac adaptation to coexisting coronary artery stenosis (CAS) is unclear. We hypothesized that concurrent HT modulates microvascular function in chronic CAS and aggravates microvascular remodeling and myocardial injury. Four groups of pigs (n=6 each) were studied: normal, CAS, HT, and CAS+HT. CAS and HT were induced by placing local irritant coils in the left circumflex coronary artery and renal artery, respectively. Six weeks later multidetector computerized tomography (CT) was used to assess systolic and diastolic function, microvascular permeability, myocardial perfusion, and responses to adenosine in the "area at risk." Microvascular architecture, inflammation, and fibrosis were then explored in cardiac tissue. Basal myocardial perfusion was similarly decreased in CAS and CAS+HT, but its response to adenosine was significantly more attenuated in CAS. Microvascular permeability in CAS+HT was greater than in CAS and was accompanied by amplified myocardial inflammation, fibrosis, and microvascular remodeling, as well as cardiac systolic and diastolic dysfunction. On the other hand, compared with normal, micro-CT-derived microvascular (20-200 μm) transmural density decreased in CAS but not in HT or CAS+HT. We conclude that the coexistence of early renovascular HT exacerbated myocardial fibrosis and vascular remodeling distal to CAS. These changes were not mediated by loss of myocardial microvessels, which were relatively preserved, but possibly by exacerbated myocardial inflammation and fibrosis. HT modulates cardiac adaptive responses to CAS and bears cardiac functional consequences. PMID:21131477

  1. Moderate exercise training promotes adaptations in coronary blood flow and adenosine production in normotensive rats

    PubMed Central

    Roque, Fernanda R.; Soci, Ursula Paula Renó; De Angelis, Katia; Coelho, Marcele A.; Furstenau, Cristina R.; Vassallo, Dalton V.; Irigoyen, Maria Claudia; Oliveira, Edilamar M.

    2011-01-01

    OBJECTIVES: Aerobic exercise training prevents cardiovascular risks. Regular exercise promotes functional and structural adaptations that are associated with several cardiovascular benefits. The aim of this study is to investigate the effects of swimming training on coronary blood flow, adenosine production and cardiac capillaries in normotensive rats. METHODS: Wistar rats were randomly divided into two groups: control (C) and trained (T). An exercise protocol was performed for 10 weeks and 60 min/day with a tail overload of 5% bodyweight. Coronary blood flow was quantified with a color microsphere technique, and cardiac capillaries were quantified using light microscopy. Adenine nucleotide hydrolysis was evaluated by enzymatic activity, and protein expression was evaluated by western blot. The results are presented as the means ± SEMs (p<0.05). RESULTS: Exercise training increased the coronary blood flow and the myocardial capillary-to-fiber ratio. Moreover, the circulating and cardiac extracellular adenine nucleotide hydrolysis was higher in the trained rats than in the sedentary rats due to the increased activity and protein expression of enzymes, such as E-NTPDase and 5′-nucleotidase. CONCLUSIONS: Swimming training increases coronary blood flow, number of cardiac capillaries, and adenine nucleotide hydrolysis. Increased adenosine production may be an important contributor to the enhanced coronary blood flow and angiogenesis that were observed in the exercise-trained rats; collectively, these results suggest improved myocardial perfusion. PMID:22189737

  2. An Investigation Of the Trade-Off Between Count Level and Image Quality in Myocardial Perfusion SPECT using Simulated Images: the Effects of Statistical Noise and Object Variability on Defect Detectability

    PubMed Central

    He, Xin; Links, Jonathan M.; Frey, Eric C.

    2010-01-01

    Quantum noise as well as anatomic and uptake variability in patient populations limits observer performance on a defect detection task in myocardial perfusion SPECT (MPS). The goal of this study was to investigate the relative importance of these two effects by varying acquisition time, which determines the count level, and assessing the change in performance on a myocardial perfusion (MP) defect detection task using both mathematical and human observers. We generated 10 sets of projections of a simulated patient population with count levels ranging from 1/128 to around 15 times a typical clinical count level to simulate different levels of quantum noise. For the simulated population we modeled variations in patient, heart and defect size, heart orientation and shape, defect location, organ uptake ratio, etc. The projection data were reconstructed using the OS-EM algorithm with no compensation or with attenuation, detector response and scatter compensation (ADS). The images were then post-filtered and reoriented to generate short axis slices. A channelized Hotelling observer (CHO) was applied to the short-axis images, and the area under the receiver operating characteristics (ROC) curve (AUC) was computed. For each noise level and reconstruction method, we optimized the number of iterations and cutoff frequencies of the Butterworth filter to maximize the AUC. Using the images obtained with the optimal iteration and cutoff frequency and ADS compensation, we performed human observer studies for 4 count levels to validate the CHO results. Both CHO and human observer studies demonstrated that observer performance was dependent on the relative magnitude of the quantum noise and the patient variation. When the count level was high, the patient variation dominated, and the AUC increased very slowly with changes in the count level for the same level of anatomic variability. When the count level was low, however, quantum noise dominated, and changes in count level resulted

  3. An investigation of the trade-off between the count level and image quality in myocardial perfusion SPECT using simulated images: the effects of statistical noise and object variability on defect detectability

    NASA Astrophysics Data System (ADS)

    He, Xin; Links, Jonathan M.; Frey, Eric C.

    2010-09-01

    Quantum noise as well as anatomic and uptake variability in patient populations limits observer performance on a defect detection task in myocardial perfusion SPECT (MPS). The goal of this study was to investigate the relative importance of these two effects by varying acquisition time, which determines the count level, and assessing the change in performance on a myocardial perfusion (MP) defect detection task using both mathematical and human observers. We generated ten sets of projections of a simulated patient population with count levels ranging from 1/128 to around 15 times a typical clinical count level to simulate different levels of quantum noise. For the simulated population we modeled variations in patient, heart and defect size, heart orientation and shape, defect location, organ uptake ratio, etc. The projection data were reconstructed using the OS-EM algorithm with no compensation or with attenuation, detector response and scatter compensation (ADS). The images were then post-filtered and reoriented to generate short-axis slices. A channelized Hotelling observer (CHO) was applied to the short-axis images, and the area under the receiver operating characteristics (ROC) curve (AUC) was computed. For each noise level and reconstruction method, we optimized the number of iterations and cutoff frequencies of the Butterworth filter to maximize the AUC. Using the images obtained with the optimal iteration and cutoff frequency and ADS compensation, we performed human observer studies for four count levels to validate the CHO results. Both CHO and human observer studies demonstrated that observer performance was dependent on the relative magnitude of the quantum noise and the patient variation. When the count level was high, the patient variation dominated, and the AUC increased very slowly with changes in the count level for the same level of anatomic variability. When the count level was low, however, quantum noise dominated, and changes in the count level

  4. Assessment of coronary artery disease using single-photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia

    SciTech Connect

    Iskandrian, A.S.; Heo, J.; Nguyen, T.; Beer, S.G.; Cave, V.; Ogilby, J.D.; Untereker, W.; Segal, B.L. )

    1991-06-01

    Thallium-201 myocardial imaging during dipyridamole-induced coronary hyperemia has been an accepted method for diagnosing coronary artery disease (CAD) and risk stratification. Adenosine is a powerful short-acting coronary vasodilator. Initial results of thallium imaging during adenosine infusion have been encouraging. In 132 patients with CAD and in 16 patients with normal coronary angiograms, adenosine was given intravenously at a dose of 0.14 mg/kg/min for 6 minutes and thallium-201 was injected at 3 minutes. The thallium images using single-photon emission computed tomography were abnormal in 47 of the 54 patients (87%) with 1-vessel, in 34 of 37 patients (92%) with 2-vessel and in 40 of 41 patients (98%) with 3-vessel CAD. The sensitivity was 92% in the 132 patients with CAD (95% confidence intervals, 86 to 96%). In patients with normal coronary angiograms, 14 of 16 patients had normal thallium images (specificity, 88%; 95% confidence intervals, 59 to 100%). The results were very similar when subgroups of patients were analyzed: those without prior myocardial infarction, elderly patients and women. The nature of the perfusion defects (fixed or reversible) was assessed in relation to whether the 4-hour delayed images were obtained with or without the reinjection technique. In patients who underwent conventional delayed imaging, there were more fixed perfusion defects than in patients with reinjection delayed imaging (16 vs 0%, p less than 0.0001). The adverse effects were mild, transient and well tolerated. Thus, adenosine thallium tomographic imaging provides a high degree of accuracy in the diagnosis of CAD. The use of the reinjection technique enhances the ability to detect reversible defects.

  5. Adenosine Stress and Rest T1 Mapping Can Differentiate Between Ischemic, Infarcted, Remote, and Normal Myocardium Without the Need for Gadolinium Contrast Agents

    PubMed Central

    Liu, Alexander; Wijesurendra, Rohan S.; Francis, Jane M.; Robson, Matthew D.; Neubauer, Stefan; Piechnik, Stefan K.; Ferreira, Vanessa M.

    2016-01-01

    Objectives The aim of this study was to evaluate the potential of T1 mapping at rest and during adenosine stress as a novel method for ischemia detection without the use of gadolinium contrast. Background In chronic coronary artery disease (CAD), accurate detection of ischemia is important because targeted revascularization improves clinical outcomes. Myocardial blood volume (MBV) may be a more comprehensive marker of ischemia than myocardial blood flow. T1 mapping using cardiac magnetic resonance (CMR) is highly sensitive to changes in myocardial water content, including MBV. We propose that T1 mapping at rest and during adenosine vasodilatory stress can detect MBV changes in normal and diseased myocardium in CAD. Methods Twenty normal controls (10 at 1.5-T; 10 at 3.0-T) and 10 CAD patients (1.5-T) underwent conventional CMR to assess for left ventricular function (cine), infarction (late gadolinium enhancement [LGE]) and ischemia (myocardial perfusion reserve index [MPRI] on first-pass perfusion imaging during adenosine stress). These were compared to novel pre-contrast stress/rest T1 mapping using the Shortened Modified Look-Locker Inversion recovery technique, which is heart rate independent. T1 values were derived for normal myocardium in controls and for infarcted, ischemic, and remote myocardium in CAD patients. Results Normal myocardium in controls (normal wall motion, MPRI, no LGE) showed normal resting T1 (954 ± 19 ms at 1.5-T; 1,189 ± 34 ms at 3.0-T) and significant positive T1 reactivity during adenosine stress compared to baseline (6.2 ± 0.5% at 1.5-T; 6.3 ± 1.1% at 3.0-T; all p < 0.0001). Infarcted myocardium showed the highest resting T1 of all tissue classes (1,442 ± 84 ms), without significant T1 reactivity (0.2 ± 1.5%). Ischemic myocardium showed elevated resting T1 compared to normal (987 ± 17 ms; p < 0.001) without significant T1 reactivity (0.2 ± 0.8%). Remote myocardium, although having comparable resting T1 to normal (955 ± 17 ms

  6. 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.

  7. Use of adenosine echocardiography for diagnosis of coronary artery disease

    SciTech Connect

    Zoghbi, W.A. )

    1991-07-01

    Two-dimensional echocardiography combined with exercise is sensitive and specific in the detection of coronary artery disease (CAD) by demonstrating transient abnormalities in wall motion. Frequently, however, patients cannot achieve maximal exercise because of various factors. Pharmacologic stress testing with intravenous adenosine was evaluated as a means of detecting CAD in a noninvasive manner. Patients with suspected CAD underwent echocardiographic imaging and simultaneous thallium 201 single-photon emission computed tomography during the intravenous administration of 140 micrograms/kg/min of adenosine. An increase in heart rate, decrease in blood pressure, and increase in double product were observed during adenosine administration. Initial observations revealed that wall motion abnormalities were induced by adenosine in areas of perfusion defects. The adenosine infusion was well tolerated, and symptoms disappeared within 1 to 2 minutes after termination of the infusion. Therefore preliminary observations suggest that adenosine echocardiography appears to be useful in the assessment of CAD.

  8. 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.

  9. The A3 adenosine receptor agonist CP-532,903 protects against myocardial ischemia/reperfusion injury via the sarcolemmal ATP sensitive potassium channel

    PubMed Central

    Wan, Tina C.; Ge, Zhi-Dong; Tampo, Akihito; Mio, Yasushi; Bienengraeber, Martin W.; Tracey, W. Ross; Gross, Garrett J.; Kwok, Wai-Meng; Auchampach, John A.

    2008-01-01

    We examined the cardioprotective profile of the new A3 adenosine receptor (AR) agonist CP-532,903 in an in vivo mouse model of infarction and an isolated heart model of global ischemia/reperfusion injury. In radioligand binding and cAMP accumulation assays using HEK 293 cells expressing recombinant mouse ARs, CP-532,903 was found to bind with high affinity to mouse A3ARs (ki = 9.0±2.5 nM) and with high selectivity versus mouse A1AR (100-fold) and A2AARs (1,000-fold). In in vivo ischemia/reperfusion experiments, pretreating mice with 30 or 100 µg/kg of CP-532,903 reduced infarct size from 59.2 ± 2.1% of the risk region in vehicle-treated mice to 42.5 ± 2.3% and 39.0 ± 2.9%, respectively. Similarly, treating isolated mouse hearts with CP-532,903 (10, 30, or 100 nM) concentration-dependently improved recovery of contractile function following 20 min of global ischemia and 45 min of reperfusion, including developed pressure and ±dP/dt. In both models of ischemia/reperfusion injury, CP-532,903 provided no benefit in studies using mice with genetic disruption of the A3AR gene (A3KO mice). In isolated heart studies, protection provided by CP-532,903 and ischemic preconditioning induced by 3 brief ischemia/reperfusion cycles were lost in Kir6.2 KO mice lacking expression of the pore-forming subunit of the sarcolemmal ATP-sensitive potassium (KATP) channel. Whole-cell patch clamp recordings provided evidence that the A3AR is functionally coupled to the sarcolemmal KATP channel in murine cardiomyocytes. We conclude that CP-532,903 is a highly selective agonist of the mouse A3AR that protects against ischemia/reperfusion injury by activating sarcolemmal KATP channels. PMID:17906066

  10. Performance of Myocardial Perfusion Imaging Using Multi-focus Fan Beam Collimator with Resolution Recovery Reconstruction in a Comparison with Conventional SPECT

    PubMed Central

    Matsutomo, Norikazu; Nagaki, Akio; Sasaki, Masayuki

    2014-01-01

    Objective(s): IQ-SPECT is an advanced high-speed SPECT modality for myocardial perfusion imaging (MPI), which uses a multi-focus fan beam collimator with resolution recovery reconstruction. The aim of this study was to compare IQ-SPECT with conventional SPECT in terms of performance, based on standard clinical protocols. In addition, we examined the concordance between conventional and IQ_SPECT in patients with coronary artery disease (CAD). Methods: Fifty-three patients, undergoing rest-gated MPI for the evaluation of known or suspected CAD, were enrolled in this study. In each patient, conventional SPECT (99mTc-tetrofosmin, 9.6 min and 201Tl, 12.9 min) was performed, immediately followed by IQ-SPECT, using a short acquisition time (4.3 min for 99mTc-tetrofosmin and 6.2 min for 201Tl). A quantitative analysis was performed on an MPI polar map, using a 20-segment model of the left ventricle. An automated analysis by gated SPECT was carried out to determine the left ventricular volume and function including end-diastolic volume (EDV), end-systolic volume (ESV), and left ventricular ejection fraction (LVEF). The degree of concordance between conventional SPECT and IQ-SPECT images was evaluated according to linear regression and Bland-Altman analyses. Results: The segmental percent uptake exhibited a significant correlation between IQ-SPECT and conventional SPECT (P<0.05). The mean differences in 99mTc-tetrofosmin studies were 1.1±6.6% (apex), 2.8±5.7% (anterior wall), 2.9±6.2% (septal wall), 4.9±6.7% (lateral wall), and 1.8±5.6% (inferior wall). Meanwhile, regarding the 201Tl-SPECT studies, these values were 1.6±6.9%, 2.0±6.6%, 2.1±5.9%, 3.3±7.2%, and 2.4±5.8%, respectively. Although the mean LVEF in IQ-SPECT tended to be higher than that observed in conventional SPECT (conventional SPECT=64.8±11.8% and IQ-SPECT=68.3±12.1% for 99mTc-tetrofosmin; conventional SPECT= 56.0±11.7% and IQ-SPECT=61.5±12.2% for 201Tl), quantitative parameters were not

  11. No Evidence of Myocardial Oxygen Deprivation in Nonischemic Heart Failure

    PubMed Central

    Dass, Sairia; Holloway, Cameron J.; Cochlin, Lowri E.; Rider, Oliver J.; Mahmod, Masliza; Robson, Matthew; Sever, Emily; Clarke, Kieran; Watkins, Hugh; Ashrafian, Houman; Karamitsos, Theodoros D.

    2015-01-01

    Background— Whether the myocardium in nonischemic heart failure experiences oxygen limitation remains a long-standing controversy. We addressed this question in patients with dilated cardiomyopathy (DCM) using a dual approach. First, we tested the changes in myocardial oxygenation between rest and stress states, using oxygenation-sensitive cardiovascular magnetic resonance. Second, we sought to assess the functional consequences of oxygen limitation at rest by measuring myocardial energetics before and after short-term oxygen supplementation. Methods and Results— Twenty-six subjects (14 DCM and 12 normal) underwent cardiac magnetic resonance imaging at 3 Tesla to assess cardiac volumes, function, oxygenation, and first-pass perfusion (0.03 mmol/kg Gd-DTPA bolus) at stress and rest (4–6 minutes IV adenosine, 140 μg/kg per minute). Signal intensity change (SIΔ) and myocardial perfusion reserve index (MPRI) were measured from oxygenation and perfusion images, respectively. Furthermore, the effect of oxygen supplementation on resting myocardial energy metabolism was tested using 31P MR spectroscopy, measuring PCr/ATP ratios in both groups at baseline and after 4 hours of oxygen via facemask in the DCM group. During stress, there were equivalent rises in rate pressure product in both groups (DCM, 76±15% and normal, 79±9%; P=0.84). MPRI was significantly reduced in DCM (1.51±0.11 versus normal 1.86±0.10; P=0.03). However, there was no difference in oxygenation between groups: SIΔ in DCM 17±3% versus normal 20±2% (P=0.38). Furthermore, at a left ventricular segmental level, there was no correlation between oxygenation-sensitive SIΔ and MPRI (R=0.06; P=0.43). Resting PCr/ATP was reduced in DCM (1.66±0.07 versus normal 2.12±0.06; P=0.002). With oxygen supplementation, there was no change in PCr/ATP (1.61±0.08; P=0.58; Δ=0.04±0.05). There was also no effect of oxygen on systolic function (ejection fraction pre oxygen, 34±1%; post oxygen, 36±2%; P=0

  12. Endothelial NO formation does not control myocardial O2 consumption in mouse heart.

    PubMed

    Kojic, Zvezdana Z; Flogel, Ulrich; Schrader, Jurgen; Decking, Ulrich K M

    2003-07-01

    To test whether endothelium-derived nitric oxide (NO) regulates mitochondrial respiration, NO was pharmacologically modulated in isolated mouse hearts, which were perfused at constant flow to sensitively detect small changes in myocardial O2 consumption (MVO2). Stimulation of NO formation by 10 microM bradykinin (BK) increased coronary venous nitrite release fivefold to 58 +/- 33 nM (n = 17). Vasodilatation by BK, adenosine (1 microM), or papaverine (10 microM) decreased perfusion pressure, left ventricular developed pressure (LVDP), and MVO2. In the presence of adenosine-induced vasodilatation, stimulation of endothelial NO synthesis by BK had no effect on LVDP and MVO2. Also, inhibition of NO formation by NG-monomethyl-l-arginine (l-NMMA, 100 microM) did not significantly alter LVDP and MVO2. Similarly, intracoronary infusion of authentic NO 2 microM were contractile dysfunction and MVO2 reduction observed. Because BK-induced stimulation of endothelial NO formation and basal NO are not sufficient to impair MVO2 in the saline-perfused mouse heart, a tonic control of the respiratory chain by endothelial NO is difficult to conceive. PMID:12609821

  13. Investigating real-time activation of adenosine receptors by bioluminescence resonance energy transfer technique

    NASA Astrophysics Data System (ADS)

    Huang, Yimei; Yang, Hongqin; Zheng, Liqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen

    2013-02-01

    Adenosine receptors play important roles in many physiological and pathological processes, for example regulating myocardial oxygen consumption and the release of neurotransmitters. The activations of adenosine receptors have been studied by some kinds of techniques, such as western blot, immunohistochemistry, etc. However, these techniques cannot reveal the dynamical response of adenosine receptors under stimulation. In this paper, bioluminescence resonance energy transfer technique was introduced to study the real-time activation of adenosine receptors by monitoring the dynamics of cyclic adenosine monophosphate (cAMP) level. The results showed that there were significant differences between adenosine receptors on real-time responses under stimulation. Moreover, the dynamics of cAMP level demonstrated that competition between adenosine receptors existed. Taken together, our study indicates that monitoring the dynamics of cAMP level using bioluminescence resonance energy transfer technique could be one potential approach to investigate the mechanism of competitions between adenosine receptors.

  14. 99Tcm-methoxy-isobutyl-isonitrile SPECT to evaluate a perfusion index from regional myocardial uptake after exercise and at rest. Results of a four hour protocol in patients with coronary heart disease and in controls.

    PubMed

    Buell, U; Dupont, F; Uebis, R; Kaiser, H J; Kleinhans, E; Reske, S N; Hanrath, P

    1990-02-01

    In 70 patients with angiographically confirmed coronary heart disease and in 10 controls, a 4 h exercise (E) (injection of 150 MBq 99Tcm-MIBI) rest (R) (800 MBq) protocol was employed. Of these, 10 patients with 21 myocardial defects after E received a third injection 24 h after. SPECT was used to image myocardial distribution, and visual findings separated three patterns of perfusion defects after E v. R (reversible [REV], partial reversible (PREV), irreversible (IRR)). Relative regional uptake was obtained from a target-like (33 ROIs) evaluation of short-axis cuts, establishing a perfusion index (PI) by relating the defect uptake to individual maximum uptake (100%) after exercise (PIE), at rest (PIR) and the respective differences Delta PI (PIR-PIE, i.e. filling in by the second 99Tcm-MIBI injection). Visually, the sensitivity was 86% in patients or 69% in involved vessels (stenoses of greater than 33%). Vascular supply areas revealed minimal PIE values of 74.7 +/- 10.6% (control), 62.4 +/- 9.2% (REV), 46.1 +/- 7.7% (PREV) and 33.5 +/- 9.9% (IRR) (p less than 0.01). Delta PI was +13.2% or +10.1% in REV or PREV (n.s.) and +2.1% in IRR (p less than 0.01) or -0.2% in controls. PIE values did not correlate to the degree of stenosis. In areas with old myocardial infarction, the same sequence of significant decrease of PIE with reversibility occurred, independent of the patency of the supplying vessel. 33 of 35 IRR defects (94.3%) revealed PIE of less than 45%, thus predicting IRR already after the E examination. PIR values from the 4 h protocol correlated to PIR values 24 h thereafter with r = 0.94 (n = 21). 99Tcm-MIBI may be employed in a short one day E-R protocol in clinical routine. Evaluation of PI seems to be a promising tool to quantify visual defects aimed at describing the perfusional state of the terminal vascular supply area. PMID:2356070

  15. Ribose-enhanced myocardial recovery following ischemia in the isolated working rat heart.

    PubMed

    Pasque, M K; Spray, T L; Pellom, G L; Van Trigt, P; Peyton, R B; Currie, W D; Wechsler, A S

    1982-03-01

    Recovery for myocardial adenosine triphosphate (ATP) following moderate periods of ischemic is dependent upon the availability of adenosine monophosphate (AMP) and diphosphate (ADP) for rephosphorylation. Recovery of AMP and ADP levels following ischemia is, in turn, determined by the rates of salvage and de novo adenine nucleotide synthesis. Phosphoribosyl pyrophosphate (PRPP) availability is rate limiting in both salvage and de novo adenine nucleotide synthesis. Parenteral ribose infusions in rats have been documented to elevate myocardial PRPP levels with resultant enhancement of adenine nucleotide synthesis. In this study postischemic recovery of myocardial function and ATP levels in isolated, working rat hearts given ribose infusions before and after ischemia was compared with recovery in control hearts subjected to the same protocol without ribose administration. The mean percent of functional recovery in control hearts following 15 minutes of warm ischemia reached values of 56.7 +/- 4.1%, 63.5% +/- 4.3%, 65.9% +/- 4.6%, and 70.5% +/- 4.7% at 2, 5, 10, and 15 minutes of work following ischemia. Hearts perfused with ribose demonstrated improved mean percent return of function at similar intervals of postischemic work with values of 67.9% +/- 4.2%, 73.7% +/- 3.7%, 81.0% +/- 3.5% (* = p less than 0.02 versus control) *and 85.4% +/- 3.3%, *respectively. Determinations of myocardial ATP levels (mumoles/gm of dry weight) made at the end of 15 minutes of postischemic work were significantly higher (p less than 0.02) in the ribose-treated hearts (18.9 +/- 0.7) than in controls (16.3 +/- 0.6). Infusion of ribose before and after ischemia is a biochemically logical method of improving postischemic myocardial ATP and functional recovery by manipulation of adenine nucleotide synthetic pathways. PMID:6174831

  16. Targeting of Adenosine Receptors in Ischemia-Reperfusion Injury

    PubMed Central

    Laubach, Victor E.; French, Brent A.; Okusa, Mark D.

    2010-01-01

    Importance of the field Ischemia-reperfusion (IR) injury is a common clinical problem after transplantation as well as myocardial infarction and stroke. IR initiates an inflammatory response leading to rapid tissue damage. Adenosine, produced in response to IR, is generally considered as a protective signaling molecule and elicits its physiological responses through four distinct adenosine receptors. The short half-life, lack of specificity, and rapid metabolism limits the use of adenosine as a therapeutic agent. Thus intense research efforts have focused on the synthesis and implementation of specific adenosine receptor agonists and antagonists as potential therapeutic agents for a variety of inflammatory conditions including IR injury. Areas covered by this review This review summarizes current knowledge on IR injury with a focus on lung, heart, and kidney, and examines studies that have advanced our understanding of the role of adenosine receptors and the therapeutic potential of adenosine receptor agonists and antagonists for the prevention of IR injury. What the reader will gain The reader will gain insight into the role of adenosine receptor signaling in IR injury. Take home message No clinical therapies are currently available that specifically target IR injury; however, targeting of specific adenosine receptors may offer therapeutic strategies in this regard. PMID:21110787

  17. Quantitative thallium-201 single-photon emission computed tomography during maximal pharmacologic coronary vasodilation with adenosine for assessing coronary artery disease

    SciTech Connect

    Nishimura, S.; Mahmarian, J.J.; Boyce, T.M.; Verani, M.S. )

    1991-09-01

    The diagnostic value of maximal pharmacologic coronary vasodilation with intravenously administered adenosine in conjunction with thallium-201 single-photon emission computed tomography (SPECT) for detection of coronary artery disease was investigated in 101 consecutive patients who had concomitant coronary arteriography. Tomographic images were assessed visually and from computer-quantified polar maps of the thallium-201 distribution. Significant coronary artery disease, defined as greater than 50% luminal diameter stenosis, was present in 70 patients. The sensitivity for detecting patients with coronary artery disease using quantitative analysis was 87% in the total group, 82% in patients without myocardial infarction and 96% in those with prior myocardial infarction; the specificity was 90%. The sensitivity for diagnosing coronary artery disease in patients without infarction with single-, double-and triple-vessel disease was 76%, 86% and 90%, respectively. All individual stenoses were identified in 68% of patients with double-vessel disease and in 65% of those with triple-vessel disease. The extent of the perfusion defects, as quantified by polar maps, was directly related to the extent of coronary artery disease. In conclusion, quantitative thallium-201 SPECT during adenosine infusion has high sensitivity and specificity for diagnosing the presence of coronary artery disease, localizing the anatomic site of coronary stenosis and identifying the majority of affected vascular regions in patients with multivessel involvement.

  18. Hemodynamic response, arrhythmic risk, and overall safety of regadenoson as a pharmacologic stress agent for myocardial perfusion imaging in chronic obstructive pulmonary disease and bronchial asthma patients.

    PubMed

    Husain, Zehra; Palani, Gurunanthan; Cabrera, Rafael; Karthikeyan, Aarthee S; Dhanalakota, Sunitha; Pathmanathan, Suba; Jacobsen, Gordon; Ananthasubramaniam, Karthik

    2012-10-01

    Regadenoson (REG) is a A2a receptor selective pharmacologic SPECT imaging agent. Its safety in unselected chronic obstructive pulmonary disease (COPD) or asthma (AM) undergoing SPECT imaging has not been well evaluated. We retrospectively identified 228 patients (COPD n = 126 and AM n = 102, Grp 1) undergoing REG SPECT from Jan to Nov 2009 and compared to 1,142 patients without COPD and AM (control, Grp 2). A standard 400 μg REG bolus was used and gated Tc-99 m tetrofosmin SPECT done. Patient demographics, REG SPECT data, side effects, arrhythmia occurrences, and any exacerbation of COPD or AM leading to treatment, hospitalization or death were evaluated. The side effect profile of Grp 1 was also compared to a historical cohort who underwent intravenous dipyridamole thallium-201 imaging and adenosine SPECT. Both groups were comparable with regards to baseline characteristics. There was 0% incidence of clinical exacerbation of COPD or AM after REG. COPD patients had more non-significant arrhythmias (58.3% vs. Grp 2, 43%, P = 0.004). There was 0% incidence of any atrio-ventricular block and only 2 instances of brief supraventricular tachycardia. When compared to the historical cohort of COPD who underwent IV dipyridamole thallium imaging, COPD in Grp 1, had more dyspnea and flushing and when compared to COPD/AM patients who underwent adenosine SPECT, Grp 1 pts had more of flushing and headache (24.9% vs. 2.8%, P = <0.001) but less of bronchospasm (1.3% vs. 6.9%, P = 0.022) and AV block (0% vs. 4.2%, P = 0.014). REG SPECT can be safely performed in COPD and AM population. PMID:22200931

  19. Comparison of image quality, myocardial perfusion, and LV function between standard imaging and single-injection ultra-low-dose imaging using a high-efficiency SPECT camera: the MILLISIEVERT study

    PubMed Central

    Einstein, Andrew J.; Blankstein, Ron; Andrews, Howard; Fish, Mathews; Padgett, Richard; Hayes, Sean W.; Friedman, John D.; Qureshi, Mehreen; Rakotoarivelo, Harivony; Slomka, Piotr; Nakazato, Ryo; Bokhari, Sabahat; Di Carli, Marcello; Berman, Daniel S.

    2015-01-01

    SPECT myocardial perfusion imaging (MPI) plays a central role in coronary artery disease diagnosis; but concerns exist regarding its radiation burden. Compared to standard Anger-SPECT (A-SPECT) cameras, new high-efficiency (HE) cameras with specialized collimators and solid-state cadmium-zinc-telluride detectors offer potential to maintain image quality (IQ), while reducing administered activity and thus radiation dose to patients. No previous study has compared IQ, interpretation, total perfusion deficit (TPD), or ejection fraction (EF) in patients receiving both ultra-low-dose (ULD) imaging on a HE-SPECT camera and standard low-dose (SLD) A-SPECT imaging. Methods We compared ULD-HE-SPECT to SLD-A-SPECT imaging by dividing the rest dose in 101 patients at 3 sites scheduled to undergo clinical A-SPECT MPI using a same day rest/stress Tc-99m protocol. Patients received HE-SPECT imaging following an initial ~130 MBq (3.5mCi) dose, and SLD-A-SPECT imaging following the remainder of the planned dose. Images were scored visually by 2 blinded readers for IQ and summed rest score (SRS). TPD and EF were assessed quantitatively. Results Mean activity was 134 MBq (3.62 mCi) for ULD-HE-SPECT (effective dose 1.15 mSv) and 278 MBq (7.50 mCi, 2.39 mSv) for SLD-A-SPECT. Overall IQ was superior for ULD-HE-SPECT (p<0.0001), with twice as many studies graded excellent quality. Extracardiac activity and overall perfusion assessment were similar. Between-method correlations were high for SRS (r=0.87), TPD (r=0.91), and EF (r=0.88). Conclusion ULD-HE-SPECT rest imaging correlates highly with SLD-A-SPECT. It has improved image quality, comparable extracardiac activity, and achieves radiation dose reduction to 1 mSv for a single injection. PMID:24982439

  20. Noninvasive diagnostic test choices for the evaluation of coronary artery disease in women: a multivariate comparison of cardiac fluoroscopy, exercise electrocardiography and exercise thallium myocardial perfusion scintigraphy

    SciTech Connect

    Hung, J.; Chaitman, B.R.; Lam, J.; Lesperance, J.; Dupras, G.; Fines, P.; Bourassa, M.G.

    1984-07-01

    Several diagnostic noninvasive tests to detect coronary and multivessel coronary disease are available for women. However, all are imperfect and it is not yet clear whether one particular test provides substantially more information than others. The aim of this study was to evaluate clinical findings, exercise electrocardiography, exercise thallium myocardial scintigraphy and cardiac fluoroscopy in 92 symptomatic women without previous infarction and determine which tests were most useful in determining the presence of coronary disease and its severity. Univariate analysis revealed two clinical, eight exercise electrocardiographic, seven myocardial scintigraphic and seven fluoroscopic variables predictive of coronary or multivessel disease with 70% or greater stenosis. The multivariate discriminant function analysis selected a reversible thallium defect, coronary calcification and character of chest pain syndrome as the variables most predictive of presence or absence of coronary disease. The ranked order of variables most predictive of multivessel disease were cardiac fluoroscopy score, thallium score and extent of ST segment depression in 14 electrocardiographic leads. Each provided statistically significant information to the model. The estimate of predictive accuracy was 89% for coronary disease and 97% for multivessel coronary disease. The results suggest that cardiac fluoroscopy or thallium scintigraphy provide significantly more diagnostic information than exercise electrocardiography in women over a wide range of clinical patient subsets.

  1. Absolute Quantitation of Myocardial Blood Flow in Human Subjects with or without Myocardial Ischemia using Dynamic Flurpiridaz F 18 Positron Emission Tomography

    PubMed Central

    Packard, René R. S.; Huang, Sung-Cheng; Dahlbom, Magnus; Czernin, Johannes; Maddahi, Jamshid

    2015-01-01

    Absolute quantitation of myocardial blood flow (MBF) by positron emission tomography (PET) is an established method of analyzing coronary artery disease (CAD) but subject to the various shortcomings of available radiotracers. Flurpiridaz F 18 is a novel PET radiotracer which exhibits properties of an ideal tracer. Methods A new absolute perfusion quantitation method with Flurpiridaz was developed, taking advantage of the early kinetics and high first-pass extraction by the myocardium of this radiotracer, and the first in human measurements of MBF performed in 7 normal subjects and 8 patients with documented CAD. PET images with time-activity curves were acquired at rest and during adenosine stress. Results In normal subjects, regional MBF between coronary artery territories did not differ significantly, leading to a mean global MBF of 0.73 mL/min/g at rest and 2.53 mL/min/g during stress, with a mean global myocardial flow reserve (MFR) of 3.70. CAD vascular territories with <50% stenosis demonstrated a mean MBF of 0.73 at rest and 2.02 during stress, leading to a mean MFR of 2.97. CAD vascular territories with ≥50% stenosis exhibited a mean MBF of 0.86 at rest and 1.43 during stress, leading to a mean MFR of 1.86. Differences in stress MBF and MFR between normal and CAD territories, as well as between <50% and ≥50% stenosis vascular territories, were significant (P<0.01). Conclusion Absolute quantitation of MBF in humans with the novel PET radiotracer Flurpiridaz is feasible over a wide range of cardiac flow in the presence or absence of stress-inducible myocardial ischemia. The significant decrease in stress MBF and ensuing MFR in CAD territories allows a clear distinction between vascular territories exhibiting stress-inducible myocardial ischemia and those with normal perfusion. PMID:25071096

  2. Adenosine diphosphate-degrading activity in placenta.

    PubMed

    Barradas, M; Khokher, M; Hutton, R; Craft, I L; Dandona, P

    1983-02-01

    1. The degradation of ADP by the placenta and umbilical artery was investigated. 2. Supernatants from incubations of finely chopped placental and umbilical arterial tissue were incubated with [14C]ADP for various durations from 0 to 30 min. 3. Products of ADP degradation were separated by thin-layer chromatography and radioactivity incorporated into each product was measured. 4. Placental supernatants induced a more rapid degradation of ADP than the umbilical artery supernatants. The main product of ADP degradation by placental supernatants at 30 min was adenosine, whereas that of umbilical artery was AMP. 5. This conversion by placenta of ADP, a potent platelet aggregator and vasoconstrictor, into adenosine, a potent platelet anti-aggregator and vasodilator, may be important in the maintenance of perfusion of the foetoplacental unit. PMID:6822058

  3. Ventricular Fibrillation Waveform Changes during Controlled Coronary Perfusion Using Extracorporeal Circulation in a Swine Model

    PubMed Central

    Kaufman, Christopher L.; Baetiong, Alvin; Radhakrishnan, Jeejabai

    2016-01-01

    Background Several characteristics of the ventricular fibrillation (VF) waveform have been found predictive of successful defibrillation and hypothesized to reflect the myocardial energy state. In an open-chest swine model of VF, we modeled “average CPR” using extracorporeal circulation (ECC) and assessed the time course of coronary blood flow, myocardial metabolism, and myocardial structure in relation to the amplitude spectral area (AMSA) of the VF waveform without artifacts related to chest compression. Methods VF was induced and left untreated for 8 minutes in 16 swine. ECC was then started adjusting its flow to maintain a coronary perfusion pressure of 10 mmHg for 10 minutes. AMSA was calculated in the frequency domain and analyzed continuously with a 2.1 s timeframe and a Tukey window that moved ahead every 0.5 s. Results AMSA progressively declined during untreated VF. With ECC, AMSA increased from 7.0 ± 1.9 mV·Hz (at minute 8) to 12.8 ± 3.3 mV·Hz (at minute 14) (p < 0.05) without subsequent increase and showing a modest correlation with coronary blood flow of borderline statistical significance (r = 0.489, p = 0.0547). Myocardial energy measurements showed marked reduction in phosphocreatine and moderate reduction in ATP with increases in ADP, AMP, and adenosine along with myocardial lactate, all indicative of ischemia. Yet, ischemia did not resolve during ECC despite a coronary blood flow of ~ 30% of baseline. Conclusion AMSA increased upon return of coronary blood flow during ECC. However, the maximal level was reached after ~ 6 minutes without further change. The significance of the findings for determining the optimal timing for delivering an electrical shock during resuscitation from VF remains to be further explored. PMID:27536996

  4. Pharmacology of the Adenosine A3 Receptor in the Vasculature and Essential Hypertension

    PubMed Central

    Ho, Ming-Fen; Low, Leanne M.; Rose’Meyer, Roselyn B.

    2016-01-01

    Background Essential hypertension is considered to be a multifactorial disorder and its aetiology has yet to be clearly identified. As the adenosine receptors have a significant role in mediating vasodilation, alterations in their structures or signalling pathways may be involved in the development of hypertension. This study aimed to measure the expression of adenosine A3 receptors in a range of cardiovascular tissues and determine whether they could be altered with essential hypertension, and to functionally test responses to adenosine A3 receptor agonists in coronary blood vessels using the isolated perfused heart preparation. Methods mRNA samples from cardiovascular tissues and a range of blood vessels were collected from 10 week old male spontaneously hypertensive rats and age-gender matched Wistar rats (n = 8). The Langendorff heart perfusion preparation was used to characterise adenosine A3 receptor mediated coronary vasodilation in the rat heart. Results Adenosine A3 receptor agonists induced coronary vasodilation. The expression of adenosine A3 receptors in cardiovascular tissues was altered in a tissue-specific pattern. Specifically, down-regulation of adenosine A3 receptor expression occurred in hypertensive hearts, which might be associated with attenuated vasodilator responses observed in coronary vessels to adenosine A3 receptor agonists. Conclusions This study demonstrated alterations in the expression of adenosine A3 receptors occurred in a tissue specific mode, and reduced adenosine A3 receptor mediated coronary vasodilation in hearts from spontaneously hypertensive rats. Our findings with regard to changes in the adenosine A3 receptor in hypertensive hearts suggest that adenosine A3 receptor might play a role in the physiopathology of essential hypertension and potentially open the way to pharmacologic manipulation of vasomotor activity by the use of adenosine A3 receptor agonists. PMID:26907173

  5. Repeatability and reproducibility of phase analysis of gated single-photon emission computed tomography myocardial perfusion imaging used to quantify cardiac dyssynchrony

    PubMed Central

    Trimble, Mark A.; Velazquez, Eric J.; Adams, George L.; Honeycutt, Emily F.; Pagnanelli, Robert A.; Barnhart, Huiman X.; Chen, Ji; Iskandrian, Ami E.; Garcia, Ernest V.; Borges-Neto, Salvador

    2010-01-01

    Background A novel method to quantify dyssynchrony has been developed using phase analysis of gated single-photon emission computed tomography perfusion imaging. We report on the effect of variability in image reconstruction on the phase analysis results (repeatability) and on the interobserver and intraobserver reproducibility of the technique. Methods Phase standard deviation (SD) and bandwidth are phase indices that quantify dyssynchrony. To evaluate repeatability, raw data sets were processed twice in 50 patients with left ventricular dysfunction and 50 normal controls. To determine the optimal processing method, two replicated phase analysis results were obtained using automated and manual base parameter placement. Reproducibility of the phase analysis was determined using the data from 20 patients. Results In normal controls, manual base parameter placement improves repeatability of the phase analysis as measured by the mean absolute difference between two reads for phase SD (12.0° vs. 1.2°, P< 0.0001) and bandwidth (33.7° vs. 3.6°, P< 0.0001). Repeatability is better for normal controls than for patients with left ventricular dysfunction for phase SD (1.2° vs. 6.0°, P < 0.0001) and bandwidth (3.6° vs. 26.5°, P < 0.0001). Reproducibility of the phase analysis is high as measured by the intraclass correlation coefficients for phase SD and bandwidth of 0.99 and 0.99 for the interobserver comparisons and 1.00 and 1.00 for the intraobserver comparisons. Conclusion A novel method to quantify dyssynchrony has been developed using gated single-photon emission computed tomography perfusion imaging. Manual base parameter placement reduces the effect that variability in image reconstruction has on phase analysis. A high degree of reproducibility of phase analysis is observed. PMID:18317303

  6. Adjunctive treatment with ticagrelor, but not clopidogrel, added to tPA enables sustained coronary artery recanalisation with recovery of myocardium perfusion in a canine coronary thrombosis model.

    PubMed

    Wang, Kai; Zhou, Xiaorong; Huang, Yanming; Khalil, Mazen; Wiktor, Dominik; van Giezen, J J J; Penn, Marc S

    2010-09-01

    Reperfusion therapy for myocardial infarction is limited by significant re-occlusion rates and less-than-optimal myocardial tissue perfusion. It was the objective of this study to assess and compare the effect of ticagrelor, the first reversibly binding oral P2Y12 receptor antagonist, with that of clopidogrel, in conjunction with thrombolytic therapy, on platelet aggregation, thrombus formation, and myocardial perfusion in a canine model. Thrombus formation was induced by electrolytic injury and blood flow was measured with a Doppler ultrasonic flowmeter. All animals received tissue plasminogen activator (tPA) (1 mg/kg over 20 min); 10 animals received clopidogrel (10 mg/kg IV bolus over 5 min), 10 animals received ticagrelor initiated with a 1-min bolus (75 microg/kg/min), followed by continuous infusion (10 microg/kg/min) for 2 h, and 10 animals received IV saline. Re-occlusion rate and cyclic flow variation decreased with ticagrelor compared to saline groups (p<0.05). Adenosine phosphate (ADP)-induced platelet aggregation decreased with ticagrelor (1.9% +/- 2.67) and clopidogrel (1.11% +/- 2.0) vs. saline (26.3% +/- 23.5, p<0.05) at the end of adjunctive therapy. Bleeding time increased in the clopidogrel compared to the ticagrelor group (p=0.01). Infarct size was reduced with ticagrelor compared to the clopidogrel and saline groups (p<0.05). Blood flow remained significantly below baseline values at 20 min after tPA administration in the saline and clopidogrel groups but not in the ticagrelor group. In conclusion, in a dog coronary thrombosis model, ticagrelor blocks ADP-induced platelet activation and aggregation; prevents platelet-mediated thrombosis; prolongs reperfusion time and reduces re-occlusion and cyclic flow variation; and significantly decreases infarct size and rapidly restores myocardial tissue perfusion. PMID:20694285

  7. 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).

  8. Effect of adenosine on the formation of prostacyclin in the rabbit isolated heart.

    PubMed Central

    Karwatowska-Prokopczuk, E.; Ciabattoni, G.; Wennmalm, A.

    1988-01-01

    1. The effect of adenosine on cardiac biosynthesis of prostacyclin (PGI2) was investigated. Rabbit hearts were perfused according to Langendorff at controlled pressure (with or without theophylline), or at controlled flow. The content of 6-keto-prostaglandin1 alpha (6-keto-PGF1 alpha, metabolite of PGI2) in the coronary effluent under basal conditions and during infusion of adenosine was determined using a highly specific radioimmunoassay. 2. In other experiments, rings of rabbit aorta were incubated with or without adenosine and the production of 6-keto-PGF1 alpha was analysed as above. 3. Administration of adenosine (10 micron) to hearts perfused at controlled pressure increased the coronary flow by up to 38%. The peak concentration of 6-keto-PGF1 alpha in the effluent exceeded the control by 177% (P less than 0.01), and the total efflux of 6-keto-PGF1 alpha exceeded the control by 179% (P less than 0.001). Theophylline (50 micron) reduced these effects of adenosine by 23%, 43% and 51%, respectively, without influencing the uptake of adenosine into the heart. 4. When adenosine (1-10 micron) was administered to hearts perfused at controlled flow, a dose-dependent decrease in the perfusion pressure, by 27% and 44% respectively, was observed. In parallel, the resulting increase in 6-keto-PGF1 alpha efflux was considerably lower (49% (P less than 0.05) and 43% (NS), respectively). A similar decrease in perfusion pressure induced in the absence of adenosine decreased the efflux of 6-keto-PGF1 alpha, by 15% (P less than 0.01) and 32% (P less than 0.001), respectively.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3052678

  9. The diagnosis and treatment of the no-reflow phenomenon in patients with myocardial infarction undergoing percutaneous coronary intervention

    PubMed Central

    Ramjane, Khalill; Han, Lei; Jin, Chang

    2008-01-01

    OBJECTIVE To review the diagnosis and treatment available for myocardial infarction patients having no-reflow in the setting of percutaneous coronary intervention (PCI). DATA SOURCES Data for the present review were obtained from searches in PubMed (1997 to 2007) using the following key terms: “acute myocardial infarction”, “no-reflow phenomenon”, “myocardial contrast echocardiography”, “coronary angiography” and “cardioprotection devices”. STUDY SELECTION Mainly original articles and critical reviews written by major research pioneers in interventional cardiology were selected. RESULTS Despite a fully patent coronary artery post-PCI for myocardial infarction, patients may experience inadequate myocardial perfusion through a given segment of the coronary circulation without angiographic evidence of mechanical vessel obstruction. This phenomenon is defined as no-reflow and is a growing problem in the field of interventional cardiology. Although voluminous clinical trial data are available, the exact mechanisms involved and which treatment should be administered as first-line therapy are currently unknown. The different techniques used to diagnose no-reflow also have their pros and cons; myocardial contrast echocardiography and coronary angiography are the most reliable techniques. In cases when no-reflow was successfully reversed, patient recovery was associated with favourable left ventricular remodelling and increased left ventricular ejection fraction, even in the absence of significant improvement in regional contractile function. CONCLUSION Based on the trials in the literature, myocardial contrast echocardiography is the gold standard for the diagnosis of no-reflow. If no-reflow occurs following PCI, treatment with intracoronary adenosine or verapamil should be administered, because this form of therapy is inexpensive and safe, improves flow in the target vessel and may reduce infarct size. PMID:19343126

  10. Absolute concentration determination of phosphorus metabolites in the Langendorff-perfused rabbit heart by phosphorus-31 nuclear magnetic resonance

    SciTech Connect

    Gard, J.K.

    1984-01-01

    The concentrations of mobile high energy phosphorus metabolites and intracellular pH of Langendorff-perfused rabbit heart have been determined under control and reduced flow conditions. Absolute concentration determination was accomplished by Lorentzian lineshape analysis after development of hexachlorocyclotriphosphazene as an external intensity standard. Hearts were demonstrated to be biochemically and physiologically competent during control perfusion periods and compromised during reduced flow conditions by independent hemodynamic and metabolic measurements coincident with the NMR experiment. Reduction in perfusate flow from 20 mL/min to 5.0 mL/min (25% flow) or 2.5 mL/min (12.5% flow) demonstrated a fall in phosphocreatine and adenosine triphosphate concentrations, a rise in cytosolic inorganic phosphate concentrations, and drops in pH. Subsequent recovery upon reflow was observed. The derived values for the free concentration of ADP were very close to the reported values of the Michaelis constant for respiratory stimulation, implicating a regulatory role for this molecule in cellular respiration. Strong evidence that the creating kinase reaction was in equilibrium in the 25% flow study was seen. The NMR observable correlated closely with myocardial performance and biochemical indices of metabolic function, and supported the use of phosphocreatine as an indicator of current metabolic integrity.

  11. Influence of atorvastatin on coronary calcifications and myocardial perfusion defects in systemic lupus erythematosus patients: a prospective, randomized, double-masked, placebo-controlled study

    PubMed Central

    2011-01-01

    Introduction Mortality in systemic lupus erythematosus (SLE) patients is influenced by an increased occurrence of severe cardiovascular complications. Statins have been proven to protect a wide spectrum of SLE patients from these complications. This study was conducted to determine the possible efficacy of atorvastatin in SLE patients as assessed by multi-detector computed tomography (MDCT)-based coronary calcium scoring and single photon emission computed tomography (SPECT) of the myocardium. Methods Sixty SLE patients in stable clinical conditions were randomized to receive either atorvastatin (40 mg daily; n = 28) or placebo (n = 32). Clinical and biochemical evaluation together with MDCT-based coronary calcium scoring and SPECT studies (Tc-99 m sestamibi) were performed at the time of randomization and after 1 year of treatment. Results At randomization, SPECT revealed perfusion defects at rest in 22 (36.7%) patients and exercise-induced defects in 8 (13.3%), whereas MDCT revealed coronary calcifications in 15 subjects (25%). Coronary calcium deposits increased after 1 year in the placebo group (plaque volume change from 35.2 ± 44.9 to 62.9 ± 72.4, P < 0.05; calcium score from 32.1 ± 39.1 to 59.5 ± 64.4; P < 0.05), but not in the atorvastatin group (plaque volume 54.5 ± 62.4 vs. 51.0 ± 47.6, P not significant; calcium score 44.8 ± 50.6 vs. 54.9 ± 62.5, P not significant). The atorvastatin group showed a decrease in total serum cholesterol (from 5.1 ± 1.2 to 4.4 ± 0.7 mmol/L, P < 0.05), LDL cholesterol (2.9 ± 1.0 to 2.3 ± 0.6 mmol/L, P < 0.05), triglycerides (1.6 ± 0.6 to 1.2 ± 0.5 mmol/L, P < 0.05), and C-reactive protein (CRP) (4.4 ± 4.1 to 2.7 ± 1.7 mg/L, P < 0.05). There was no change in the mean Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score in patients from both groups. Perfusion defects observed at randomization showed no change after one year treatment with atorvastatin. Conclusions In SLE patients 40 mg of

  12. Diagnostic Performance of First-Pass Myocardial Perfusion Imaging without Stress with Computed Tomography (CT) Compared with Coronary CT Angiography Alone, with Fractional Flow Reserve as the Reference Standard

    PubMed Central

    Osawa, Kazuhiro; Miyoshi, Toru; Miki, Takashi; Koyama, Yasushi; Sato, Shuhei; Kanazawa, Susumu; Ito, Hiroshi

    2016-01-01

    Coronary computed tomography angiography (CCTA) in combination with first-pass CT myocardial perfusion imaging (MPI) has a better diagnostic performance than CCTA alone, compared with invasive coronary angiography as the reference standard. The aim of this study was to investigate the additional diagnostic value of first-pass CT-MPI without stress for detecting hemodynamic significance of coronary stenosis, compared with invasive fractional flow reserve (FFR). We recruited 53 patients with suspected coronary artery disease undergoing both CCTA and first-pass CT-MPI without stress and invasive FFR, and 75 vessels were analyzed. We used the same raw data for CCTA and CT-MPI. First-pass CT-MPI was reconstructed by examining the diastolic signal densities as a bull’s eye map. Invasive FFR <0.8 was considered as positive. On per-vessel analysis, the area under the receiver operating characteristic curve for CCTA plus first-pass CT-MPI and CCTA alone was 0.81 (0.73–0.90) and 0.70 (0.61–0.81), respectively (P = 0.036). CCTA plus first-pass CT-MPI without stress showed 0.73 sensitivity, 0.74 specificity, 0.53 positive predictive value, and 0.87 negative predictive value for detecting hemodynamically significant coronary stenosis. First-pass CT-MPI without stress correctly reclassified 38% of CCTA false-positive vessels as true negative. First-pass CT-MPI without stress combined with CCTA demonstrated excellent diagnostic accuracy, compared with invasive FFR as the reference standard. This technique could complement CCTA for diagnosis of coronary artery disease. PMID:26894686

  13. Diagnostic Performance of First-Pass Myocardial Perfusion Imaging without Stress with Computed Tomography (CT) Compared with Coronary CT Angiography Alone, with Fractional Flow Reserve as the Reference Standard.

    PubMed

    Osawa, Kazuhiro; Miyoshi, Toru; Miki, Takashi; Koyama, Yasushi; Sato, Shuhei; Kanazawa, Susumu; Ito, Hiroshi

    2016-01-01

    Coronary computed tomography angiography (CCTA) in combination with first-pass CT myocardial perfusion imaging (MPI) has a better diagnostic performance than CCTA alone, compared with invasive coronary angiography as the reference standard. The aim of this study was to investigate the additional diagnostic value of first-pass CT-MPI without stress for detecting hemodynamic significance of coronary stenosis, compared with invasive fractional flow reserve (FFR). We recruited 53 patients with suspected coronary artery disease undergoing both CCTA and first-pass CT-MPI without stress and invasive FFR, and 75 vessels were analyzed. We used the same raw data for CCTA and CT-MPI. First-pass CT-MPI was reconstructed by examining the diastolic signal densities as a bull's eye map. Invasive FFR <0.8 was considered as positive. On per-vessel analysis, the area under the receiver operating characteristic curve for CCTA plus first-pass CT-MPI and CCTA alone was 0.81 (0.73-0.90) and 0.70 (0.61-0.81), respectively (P = 0.036). CCTA plus first-pass CT-MPI without stress showed 0.73 sensitivity, 0.74 specificity, 0.53 positive predictive value, and 0.87 negative predictive value for detecting hemodynamically significant coronary stenosis. First-pass CT-MPI without stress correctly reclassified 38% of CCTA false-positive vessels as true negative. First-pass CT-MPI without stress combined with CCTA demonstrated excellent diagnostic accuracy, compared with invasive FFR as the reference standard. This technique could complement CCTA for diagnosis of coronary artery disease. PMID:26894686

  14. Adenosine and Bone Metabolism

    PubMed Central

    Mediero, Aránzazu; Cronstein, Bruce N.

    2013-01-01

    Bone is a dynamic organ that undergoes continuous remodeling whilst maintaining a balance between bone formation and resorption. Osteoblasts, which synthesize and mineralize new bone, and osteoclasts, the cells that resorb bone, act in concert to maintain bone homeostasis. In recent years, there has been increasing appreciation of purinergic regulation of bone metabolism. Adenosine, released locally, mediates its physiologic and pharmacologic actions via interactions with G-protein coupled receptors and recent work has indicated that these receptors are involved in the regulation of osteoclast differentiation and function, as well as osteoblast differentiation and bone formation. Moreover, adenosine receptors also regulate chondrocyte and cartilage homeostasis. These recent findings underscore the potential therapeutic importance of adenosine receptors in regulating bone physiology and pathology. PMID:23499155

  15. Adenosine receptor interactions and anxiolytics.

    PubMed

    Bruns, R F; Katims, J J; Annau, Z; Snyder, S H; Daly, J W

    1983-12-01

    [3H]-N6-cyclohexyladenosine and [3H]-1,3-diethyl-8-phenylxanthine label the A1 subtype of adenosine receptor in brain membranes. The affinities of methylxanthines in competing for A1 adenosine receptors parallel their potencies as locomotor stimulants. The adenosine agonist N6-(phenylisopropyl) adenosine is a potent locomotor depressant. Both diazepam and N6-(L-phenylisopropyl)adenosine cause locomotor stimulation in a narrow range of subdepressant doses. Combined stimulant doses of the two agents depress motor activity, as do larger doses of either one, given separately. Evidence supporting and against the hypothesis that some of the actions of benzodiazepines are mediated via the adenosine system is reviewed. A number of compounds interact with both systems, probably because of physico-chemical similarities between adenosine and diazepam. It is concluded that of the four classic actions of benzodiazepines, the sedative and muscle relaxant (but not anxiolytic or anticonvulsant) actions could possibly be mediated by adenosine. PMID:6199685

  16. Adenosine in fibrosis

    PubMed Central

    Chan, Edwin S. L.

    2011-01-01

    Adenosine is an endogenous autocoid that regulates a multitude of bodily functions. Its anti-inflammatory actions are well known to rheumatologists since it mediates many of the anti-inflammatory effects of a number of antirheumatic drugs such as methotrexate. However, inflammatory and tissue regenerative responses are intricately linked, with wound healing being a prime example. It has only recently been appreciated that adenosine has a key role in tissue regenerative and fibrotic processes. An understanding of these processes may shed new light on potential therapeutic options in diseases such as scleroderma where tissue fibrosis features prominently. PMID:19949965

  17. Endogenous adenosine is an autacoid feedback inhibitor of chloride transport in the shark rectal gland.

    PubMed Central

    Kelley, G G; Aassar, O S; Forrest, J N

    1991-01-01

    The present studies define the physiologic role of endogenous adenosine in the perfused shark rectal gland, a model epithelia for hormone-stimulated chloride transport. Chloride ion secretion, and venous adenosine and inosine concentrations increased in parallel in response to hormone stimulation. From a basal rate of 157 +/- 26 mu eq/h per g, chloride secretion increased to 836 +/- 96 and 2170 +/- 358 with 1 and 10 microM forskolin, venous adenosine increased from 5.0 +/- 1 to 126 +/- 29 and 896 +/- 181 nM, and inosine increased from 30 +/- 9 to 349 +/- 77 and 1719 +/- 454 nM (all P less than 0.01). Nitrobenzylthioinosine (NBTI), a nucleoside transport inhibitor, completely blocked the release of adenosine and inosine. Inhibition of chloride transport with bumetanide, an inhibitor of the Na+/K+/2Cl- cotransporter, or ouabain, an inhibitor of Na+/K+ ATPase activity, reduced venous adenosine and inosine to basal values. When the interaction of endogenous adenosine with extracellular receptors was prevented by adenosine deaminase, NBTI, or 8-phenyltheophylline, the chloride transport response to secretagogues increased by 1.7-2.3-fold. These studies demonstrate that endogenous adenosine is released in response to hormone-stimulated cellular work and acts at A1 adenosine receptors as a feedback inhibitor of chloride transport. Images PMID:1752953

  18. Adenosine deaminase inhibition enhances the inotropic response mediated by A1 adenosine receptor in hyperthyroid guinea pig atrium.

    PubMed

    Kemeny-Beke, Adam; Jakab, Anita; Zsuga, Judit; Vecsernyes, Miklos; Karsai, Denes; Pasztor, Fanni; Grenczer, Maria; Szentmiklosi, Andras Jozsef; Berta, Andras; Gesztelyi, Rudolf

    2007-08-01

    The aim of the present study was to test the hypothesis that inhibition of adenosine deaminase (ADA) enhances the efficiency of signal-transduction of myocardial A1 adenosine receptors in hyperthyroidism. The inotropic response to N6-cyclopentyladenosine (CPA), a selective A1 adenosine receptor agonist resistant to ADA, was investigated in the absence or presence of erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), an ADA and cGMP-stimulated 3',5'-cyclic nucleotide phosphodiesterase (PDE2) inhibitor, or of pentostatin (2'-deoxycoformycin; DCF), an exclusive ADA inhibitor, in left atria isolated from eu- or hyperthyroid guinea pigs. Both ADA inhibitors enhanced the effect of CPA only in hyperthyroid atria. EHNA significantly increased the Emax (mean+/-S.E.M.) from 83.8+/-1.2% to 93.4+/-1.2%, while DCF significantly decreased the logEC50 from -7.5+/-0.07 to -7.83+/-0.07 in hyperthyroid samples. Conversely, EHNA also diminished the logEC50 (from -7.5+/-0.07 to -7.65+/-0.07) and DCF also raised the Emax (from 83.8+/-1.2% to 85.7+/-2%) in hyperthyroidism, but these changes were not significant. In conclusion, ADA inhibition moderately but significantly enhanced the efficiency of A(1) adenosine receptor signaling pathway in the hyperthyroid guinea pig atrium. This suggests that elevated intracellular adenosine level caused by ADA inhibition may improve the suppressed responsiveness to A1 adenosine receptor agonists associated with the hyperthyroid state. Alternatively or in addition, the role of decreased concentration of adenosine degradation products cannot be excluded. Furthermore, in the case of EHNA, inhibition of PDE2 also appears to contribute to the enhanced A1 adenosine receptor signaling in the hyperthyroid guinea pig atrium. PMID:17574432

  19. Possible therapeutic benefits of adenosine-potentiating drugs in reducing age-related degenerative disease in dogs and cats.

    PubMed

    Scaramuzzi, R J; Baker, D J

    2003-10-01

    Adenosine is a ubiquitous, biologically important molecule that is a precursor of other biologically active molecules. It also is a component of some co-factors and has distinct physiological actions in its own right. Levels are maintained by synthesis from dietary precursors and re-cycling. The daily turnover of adenosine is very high. Adenosine can act either as a hormone by binding to adenosine receptors, four adenosine receptor subtypes have been identified, and as an intracellular modulator, after transport into the cell by membrane transporter proteins. One of the principal intracellular actions of adenosine is inhibition of the enzyme phosphodiesterase. Extracellular adenosine also has specific neuromodulatory actions on dopamine and glutamate. Selective and nonselective agonists and antagonists of adenosine are available. The tasks of developing, evaluating and exploiting the therapeutic potential of these compounds is still in its infancy. Adenosine has actions in the central nervous system (CNS), heart and vascular system, skeletal muscle and the immune system and the presence of receptors suggests potential actions in the gonads and other organs. Adenosine agonists improve tissue perfusion through actions on vascular smooth muscle and erythrocyte fluidity and they can be used to improve the quality of life in aged dogs. This article reviews the therapeutic potential of adenosine-potentiating drugs in the treatment of age-related conditions in companion animals, some of which may be exacerbated by castration or spaying at an early age. PMID:14633184

  20. Adenosine and sleep

    SciTech Connect

    Yanik, G.M. Jr.

    1987-01-01

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A/sub 1/ receptors, /sup 3/H-L-PIA binding was measured. The Bmax values for /sup 3/H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in /sup 3/H-L-PIA binding resulted from REM sleep deprivation and not from stress.

  1. Cardiac Function, Perfusion, Metabolism, and Innervation following Autologous Stem Cell Therapy for Acute ST-Elevation Myocardial Infarction. A FINCELL-INSIGHT Sub-Study with PET and MRI

    PubMed Central

    Mäki, Maija T.; Koskenvuo, Juha W.; Ukkonen, Heikki; Saraste, Antti; Tuunanen, Helena; Pietilä, Mikko; Nesterov, Sergey V.; Aalto, Ville; Airaksinen, K. E. Juhani; Pärkkä, Jussi P.; Lautamäki, Riikka; Kervinen, Kari; Miettinen, Johanna A.; Mäkikallio, Timo H.; Niemelä, Matti; Säily, Marjaana; Koistinen, Pirjo; Savolainen, Eeva-Riitta; Ylitalo, Kari; Huikuri, Heikki V.; Knuuti, Juhani

    2012-01-01

    Purpose: Beneficial mechanisms of bone marrow cell (BMC) therapy for acute ST-segment elevation myocardial infarct (STEMI) are largely unknown in humans. Therefore, we evaluated the feasibility of serial positron emission tomography (PET) and MRI studies to provide insight into the effects of BMCs on the healing process of ischemic myocardial damage. Methods: Nineteen patients with successful primary reteplase thrombolysis (mean 2.4 h after symptoms) for STEMI were randomized for BMC therapy (2.9 × 106 CD34+ cells) or placebo after bone marrow aspiration in a double-blind, multi-center study. Three days post-MI, coronary angioplasty, and paclitaxel eluting stent implantation preceded either BMC or placebo therapy. Cardiac PET and MRI studies were performed 7–12 days after therapies and repeated after 6 months, and images were analyzed at a central core laboratory. Results: In BMC-treated patients, there was a decrease in [11C]-HED defect size (−4.9 ± 4.0 vs. −1.6 ± 2.2%, p = 0.08) and an increase in [18F]-FDG uptake in the infarct area at risk (0.06 ± 0.09 vs. −0.05 ± 0.16, p = 0.07) compared to controls, as well as less left ventricular dilatation (−4.4 ± 13.3 vs. 8.0 ± 16.7 mL/m2, p = 0.12) at 6 months follow-up. However, BMC treatment was inferior to placebo in terms of changes in rest perfusion in the area at risk (−0.09 ± 0.17 vs. 0.10 ± 0.17, p = 0.03) and infarct size (0.4 ± 4.2 vs. −5.1 ± 5.9 g, p = 0.047), and no effect was observed on ejection fraction (p = 0.37). Conclusion: After the acute phase of STEMI, BMC therapy showed only minor trends of long-term benefit in patients with rapid successful thrombolysis. There was a trend of more decrease in innervation defect size and enhanced glucose metabolism in the infarct-related myocardium and also a trend of less ventricular dilatation in the BMC-treated group compared to placebo. However, no

  2. PET: Is myocardial flow quantification a clinical reality?

    PubMed

    Saraste, Antti; Kajander, Sami; Han, Chunlei; Nesterov, Sergey V; Knuuti, Juhani

    2012-10-01

    Positron emission tomography (PET) enables quantitative measurements of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Recent developments and improved availability of PET technology have resulted in growing interest in translation of quantitative flow analysis from mainly a research tool to routine clinical practice. Quantitative PET measurements of absolute MBF and MFR have potential to improve accuracy of myocardial perfusion imaging in diagnosis of multivessel coronary artery disease as well as definition of the extent and functional importance of stenoses. This article reviews recent advances and experience in the quantitative myocardial perfusion imaging together with issues that need to be resolved for quantitative analysis to become clinical reality. PMID:22733534

  3. Estimation of skeletal muscle interstitial adenosine during forearm dynamic exercise in humans

    NASA Technical Reports Server (NTRS)

    Costa, F.; Heusinkveld, J.; Ballog, R.; Davis, S.; Biaggioni, I.

    2000-01-01

    It has been proposed that adenosine is a metabolic signal that triggers activation of muscle afferents involved in the exercise pressor reflex. Furthermore, exogenous adenosine induces sympathetic activation that mimics the exercise pressor reflex, and blockade of adenosine receptors inhibits sympathetic activation induced by exercise. Thus, we hypothesize that adenosine is released locally by the muscle during exercise. We used microdialysis probes, placed in the flexor digitorium superficialis muscle, to estimate muscle interstitial adenosine levels in humans. We estimated resting in vivo muscle interstitial adenosine concentrations (0.292+/-0.058 micromol/L, n=4) by perfusing increasing concentrations of adenosine to determine the gradient produced in the dialysate. Muscle interstitial adenosine concentrations increased from 0.23+/-0.04 to 0.82+/-0.14 micromol/L (n=14, P<0.001) during intermittent dynamic exercise at 50% of maximal voluntary contraction. Lactate increased from 0.8+/-0.1 to 2.3+/-0.3 mmol/L (P<0.001). Lower intensity (15% maximal voluntary contraction) intermittent dynamic exercise increased adenosine concentrations from 0.104+/-0.02 to 0.42+/-0.16 micromol/L (n=7). The addition of ischemia to this low level of exercise produced a greater increase in adenosine (from 0.095+/-0.02 to 0.48+/-0.2 micromol/L) compared with nonischemic exercise (0. 095+/-0.02 to 0.25+/-0.12 micromol/L). These results indicate that microdialysis is useful in estimating adenosine concentrations and in reflecting changes in muscle interstitial adenosine during dynamic exercise in humans.

  4. 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.

  5. Regional myocardial blood flow and coronary vascular reserve in unanesthetized ponies during pacing-induced ventricular tachycardia

    SciTech Connect

    Parks, C.; Manohar, M.; Lundeen, G.

    1983-08-01

    To examine the effects of tachycardia on coronary circulation, transmural distribution of myocardial blood flow (MBF, 15-micron diameter radionuclide-labeled microspheres) was studied in six healthy adult ponies at rest (heart rate . 60 +/- 7 beats . min-1), during ventricular pacing at 150 and 200 beats . min-1, as well as with ventricular pacing at 250 beats . min-1 before and during maximal coronary vasodilatation (iv adenosine infusion; 4 mumole . kg-1 . min-1). Mean aortic pressure and cardiac output were unchanged from control values with ventricular pacing. Whereas ventricular pacing at 150 and 200 beats . min-1 resulted in a progressive uniform increase in transmural MBF and well-maintained endo:epi perfusion ratio, pacing at 250 beats . min-1 did not result in a further increase in MBF compared to pacing at 200 beats . min-1 and the left ventricular (LV) subendocardial:subepicardial (endo:epi) perfusion ratio was significantly less than 1.00 (0.87 +/- 0.05). Blood flow to the LV papillary muscles and subendocardium was significantly less than that recorded at 200 beats . min-1. The LV endo:epi perfusion ratio with ventricular pacing at 250 beats . min-1 during adenosine infusion resulted in a decrease in mean aortic pressure (63% of control value) and a marked further reduction in blood flow to the LV papillary muscles as well as the LV subendocardium, while MBF increased dramatically in the LV subepicardium compared to values observed during ventricular pacing at 250 beats . min-1 alone. These data demonstrate that coronary vasomotion functions to maintain LV subendocardial blood flow in the pony myocardium at a heart rate of 200 beats . min-1, while at 250 beats . min-1 exhaustion of coronary vasodilator reserve in the deeper layers limits further increase in MBF.

  6. Cardioplegia and myocardial preservation during cardiopulmonary bypass.

    PubMed

    Engelman, R M; Levitsky, S; O'Donoghue, M J; Auvil, J

    1978-09-01

    A standard experimental protocol was developed to explore the role of hypothermia and potassium cardioplegia in myocardial preservation during 120 minutes of ischemic arrest followed by 30 minutes of reperfusion. Seven different experimental groups of six animals each were evaluated using an in-vivo pig heart preparation. Hypothermic arrest without cardioplegia and cardioplegic arrest at normothermia were each compared to hypothermic cardioplegia. In addition, the use of an asanguineous hypothermic coronary perfusate without cardioplegia was compared to both multidose cardioplegia and single-dose cardioplegia followed by the same asanguineous perfusate. The parameters measured included: myocardial contractility and compliance, myocardial blood flow, endocardial/epicardial blood flow ratio, and electron microscopic studies. Myocardial preservation was inadequate with hypothermic arrest alone (without cardioplegia; and with cardioplegia at normothermia. In both experimental groups, myocardial contractility and compliance were so depressed that the) could not be accurately measured following ischemia and reperfusion while coronary blood flow remained significantly elevated. Preservation was improved but still inadequate following myocardial washout with a normokalemic or hypokalemic perfusate and following single dose cardioplegia plus myocardial washout. In the latter four groups, contractility ranged from 42 to 78% of control, and there was a decrease in compliance of 16 to 78%. Adequate preservation was found only after hypothermia and multidose potassium (35 mEq/L) cardioplegia. In this group, contractility was 129 +/- 13% of control and compliance increased by 21 +/- 24% compared to that of the control. PMID:14740689

  7. Peri-infarct ischaemia assessed by cardiovascular MRI: comparison with quantitative perfusion single photon emission CT imaging

    PubMed Central

    Cochet, H; Bullier, E; Ragot, C; Gilbert, S H; Pucheu, Y; Laurent, F; Coste, P; Bordenave, L; Montaudon, M

    2014-01-01

    Objective: To develop a new method for the cardiac MR (CMR) quantification of peri-infarct ischaemia using fused perfusion and delayed–enhanced images and to evaluate this method using quantitative single photon emission CT (SPECT) imaging as a reference. Methods: 40 patients presenting with peri-infarct ischaemia on a routine stress 99mTc-SPECT imaging were recruited. Within 8 days of the SPECT study, myocardial perfusion was evaluated using stress adenosine CMR. Using fused perfusion and delayed–enhanced images, peri-infarct ischaemia was quantified as the percentage of myocardium with stress-induced perfusion defect that was adjacent to and larger than a scar. This parameter was compared with both the percent myocardium ischaemia (SD%) and the ischaemic total perfusion deficit (TPD). The diagnostic performance of CMR in detection of significant coronary artery stenosis (of ≥70%) was also determined. Results: On SPECT imaging, in addition to peri-infarct ischaemia, reversible perfusion abnormalities were detected in a remote zone in seven patients. In the 33 patients presenting with only peri-infarct ischaemia, the agreement between CMR peri-infarct ischaemia and both SD% and ischaemic TPD was excellent [intraclass coefficient of correlation (ICC) = 0.969 and ICC = 0.877, respectively]. CMR-defined peri-infarct ischaemia for the detection of a significant coronary artery stenosis showed an areas under receiver–operating characteristic curve of 0.856 (95% confidence interval, 0.680–0.939). The best cut-off value was 8.1% and allowed a 72% sensitivity, 96% specificity, 60% negative predictive value and 97% positive predictive value. Conclusion: This proof-of-concept study shows that CMR imaging has the potential as a test for quantification of peri-infarct ischaemia. Advances in knowledge: This study demonstrates the proof of concept of a commonly known intuitive idea, that is, evaluating the peri-infarct ischaemic burden by subtracting delayed

  8. Myocardial imaging artifacts caused by mitral valve annulus calcification

    SciTech Connect

    Wagoner, L.E.; Movahed, A.; Reeves, W.C. )

    1991-02-01

    Knowledge of imaging artifact of myocardial perfusion studies with thallium-201 is critical for improving the diagnostic accuracy of coronary artery disease. Three patients are described who underwent exercise or pharmacologic stress thallium-201 imaging studies and had a moderate, fixed myocardial perfusion defect (scar) involving the posterolateral and inferoposterior walls of the left ventricle. This was an imaging artifact caused by a heavily calcified mitral valve annulus.

  9. Adenosine kinase inhibitors attenuate opiate withdrawal via adenosine receptor activation.

    PubMed

    Kaplan, G B; Coyle, T S

    1998-11-27

    Previous studies have demonstrated a role for adenosine in mediating opiate effects. This study examines the effects of indirect activation of adenosine receptors, via treatment with adenosine kinase inhibitors, on the expression of opiate withdrawal in mice. Mice receive chronic morphine treatment via implantation of subcutaneous morphine pellets (75 mg) for 72 h. Mice then receive parenteral treatment with adenosine kinase inhibitors, either 5'-amino-5'-deoxyadenosine (2, 5, 20, 40 mg/kg, intraperitoneal or i.p.) or iodotubericidin (1, 2, 5 mg/kg, i.p.), followed by naloxone injection and opiate withdrawal signs are measured over 20 min. Both adenosine kinase inhibitors significantly reduce the following opiate withdrawal signs in a dose-dependent manner compared to vehicle: withdrawal jumps, teeth chattering, forepaw tremors, and forepaw treads. Additionally, 5'-amino-5'-deoxyadenosine significantly reduces withdrawal-induced diarrhea and weight loss. Effects of 5'-amino-5'-deoxyadenosine (40 mg/kg) on opiate withdrawal signs appear to be mediated via adenosine receptor activation as they are reversed by pretreatment by adenosine receptor antagonist caffeine (20 mg, i.p.) but not by selective phosphodiesterase inhibitor Ro 20-1724 (10 mg/kg, i.p.). Adenosine receptor activation via adenosine kinase inhibitor treatment attenuates opiate withdrawal and these agents may be generally useful in the treatment of drug withdrawal syndromes. PMID:9865523

  10. Dynamic CT perfusion measurement in a cardiac phantom.

    PubMed

    Ziemer, Benjamin P; Hubbard, Logan; Lipinski, Jerry; Molloi, Sabee

    2015-10-01

    Widespread clinical implementation of dynamic CT myocardial perfusion has been hampered by its limited accuracy and high radiation dose. The purpose of this study was to evaluate the accuracy and radiation dose reduction of a dynamic CT myocardial perfusion technique based on first pass analysis (FPA). To test the FPA technique, a pulsatile pump was used to generate known perfusion rates in a range of 0.96-2.49 mL/min/g. All the known perfusion rates were determined using an ultrasonic flow probe and the known mass of the perfusion volume. FPA and maximum slope model (MSM) perfusion rates were measured using volume scans acquired from a 320-slice CT scanner, and then compared to the known perfusion rates. The measured perfusion using FPA (P(FPA)), with two volume scans, and the maximum slope model (P(MSM)) were related to known perfusion (P(K)) by P(FPA) = 0.91P(K) + 0.06 (r = 0.98) and P(MSM) = 0.25P(K) - 0.02 (r = 0.96), respectively. The standard error of estimate for the FPA technique, using two volume scans, and the MSM was 0.14 and 0.30 mL/min/g, respectively. The estimated radiation dose required for the FPA technique with two volume scans and the MSM was 2.6 and 11.7-17.5 mSv, respectively. Therefore, the FPA technique can yield accurate perfusion measurements using as few as two volume scans, corresponding to approximately a factor of four reductions in radiation dose as compared with the currently available MSM. In conclusion, the results of the study indicate that the FPA technique can make accurate dynamic CT perfusion measurements over a range of clinically relevant perfusion rates, while substantially reducing radiation dose, as compared to currently available dynamic CT perfusion techniques. PMID:26156231

  11. Ticagrelor Does Not Inhibit Adenosine Transport at Relevant Concentrations: A Randomized Cross-Over Study in Healthy Subjects In Vivo

    PubMed Central

    Rongen, G. A.; van den Broek, P. H. H.; Bilos, A.; Donders, A. R. T.; Gomes, M. E.; Riksen, N. P.

    2015-01-01

    Background and Purpose In patients with myocardial infarction, ticagrelor reduces cardiovascular and sepsis-related mortality, and can cause dyspnea. It is suggested that this is caused by adenosine receptor stimulation, because in preclinical studies, ticagrelor blocks the nucleoside transporter and increases cellular ATP release. We now investigated the effects of ticagrelor on the adenosine system in humans in vivo. Experimental Approach In a double-blinded, placebo-controlled cross-over trial in 14 healthy subjects, we have tested whether ticagrelor (180 mg) affects adenosine- and dipyridamole-induced forearm vasodilation, as surrogates of nucleoside uptake inhibition and adenosine formation, respectively. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was measured. Primary endpoint was adenosine-induced vasodilation. Key Results Ticagrelor did not affect adenosine- or dipyridamole-induced forearm vasodilation. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was not affected by ticagrelor. In vitro, ticagrelor dose-dependently inhibited nucleoside uptake, but only at supra-physiological concentrations. Conclusion and Implications In conclusion, at relevant plasma concentration, ticagrelor does not affect adenosine transport, nor adenosine formation in healthy subjects. Therefore, it is unlikely that this mechanism is a relevant pleiotropic effect of ticagrelor. Trial Registration ClinicalTrials.gov NCT01996735 PMID:26509673

  12. Adenosine receptor desensitization and trafficking.

    PubMed

    Mundell, Stuart; Kelly, Eamonn

    2011-05-01

    As with the majority of G-protein-coupled receptors, all four of the adenosine receptor subtypes are known to undergo agonist-induced regulation in the form of desensitization and trafficking. These processes can limit the ability of adenosine receptors to couple to intracellular signalling pathways and thus reduce the ability of adenosine receptor agonists as well as endogenous adenosine to produce cellular responses. In addition, since adenosine receptors couple to multiple signalling pathways, these pathways may desensitize differentially, while the desensitization of one pathway could even trigger signalling via another. Thus, the overall picture of adenosine receptor regulation can be complex. For all adenosine receptor subtypes, there is evidence to implicate arrestins in agonist-induced desensitization and trafficking, but there is also evidence for other possible forms of regulation, including second messenger-dependent kinase regulation, heterologous effects involving G proteins, and the involvement of non-clathrin trafficking pathways such as caveolae. In this review, the evidence implicating these mechanisms is summarized for each adenosine receptor subtype, and we also discuss those issues of adenosine receptor regulation that remain to be resolved as well as likely directions for future research in this field. PMID:20550943

  13. Genetics Home Reference: adenosine deaminase 2 deficiency

    MedlinePlus

    ... Health Conditions adenosine deaminase 2 deficiency adenosine deaminase 2 deficiency Enable Javascript to view the expand/collapse ... PDF Open All Close All Description Adenosine deaminase 2 (ADA2) deficiency is a disorder characterized by abnormal ...

  14. Influence of Thromboxane A2 on the Regulation of Adenosine Triphosphate-Sensitive Potassium Channels in Mouse Ventricular Myocytes

    PubMed Central

    Jeong, In Seok; Cho, Hwa Jin; Cho, Jeong Gwan; Kim, Sang Hyung; Na, Kook Joo

    2016-01-01

    Background and Objectives Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels play an important role in myocardial protection. We examined the effects of thromboxane A2 on the regulation of KATP channel activity in single ventricular myocytes. Subjects and Methods Single ventricular myocytes were isolated from the hearts of adult Institute of Cancer Research (ICR) mice by enzymatic digestion. Single channel activity was recorded by excised inside-out and cell-attached patch clamp configurations at −60 mV holding potential during the perfusion of an ATP-free K-5 solution. Results In the excised inside-out patches, the thromboxane A2 analog, U46619, decreased the KATP channel activity in a dose-dependent manner; however, the thromboxane A2 receptor antagonist, SQ29548, did not significantly attenuate the inhibitory effect of U46619. In the cell-attached patches, U46619 inhibited dinitrophenol (DNP)-induced KATP channel activity in a dose-dependent manner, and SQ29548 attenuated the inhibitory effects of U46619 on DNP-induced KATP channel activity. Conclusion Thromboxane A2 may inhibit KATP channel activity, and may have a harmful effect on ischemic myocardium. PMID:27482267

  15. Prognostic value of radionuclide exercise testing after myocardial infarction

    SciTech Connect

    Schocken, D.D.

    1984-08-01

    Abnormal systolic ventricular function and persistent ischemia are sensitive indicators of poor prognosis following myocardial infarction. The use of exercise improves the utility of both radionuclide ventriculography and myocardial perfusion scintigraphy in the identification of postinfarction patients at high risk of subsequent cardiac events. 51 references.

  16. Radioiodine therapy of hyperthyroidism precludes thallium-201 myocardial scintigraphy

    SciTech Connect

    Orzel, J.A.; Kruyer, W.B.; Borchert, R.D.

    1987-02-01

    The authors attempted to perform Tl-201 myocardial perfusion scintigraphy in a 42-year-old man 23 and 35 days after he received 9.8 mCi of oral I-131 for documented Graves' disease. Interference from primary and scattered photons from residual thyroid I-131 made Tl-201 myocardial scintigraphy technically impossible. A series of phantom and patient studies using I-131 and Tl-201 were performed, yielding guidelines for planning Tl-201 myocardial scintigraphy following radioiodine therapy.

  17. [Adenosine and its role in physiology].

    PubMed

    Novotný, J

    2015-01-01

    Adenosine is not just a major component of adenine nucleotides and ribonucleic acids, but also has its own signaling functions. ExtraceIlular level of adenosine in an organism is strictly maintained through the balance between its formation, degradation and transport. Adenosine is formed by enzymatic degradation of adenosine triphosphate and eliminated by phosphorylation to adenosine monophosphate or by deamination to inosine. Transport of adenosine across the cell membrane is ensured by equilibrative and concentrative nucleoside transporters. All these processes participate in maintenance of adenosine level under normal conditions, but a balanced equilibrium can be disrupted in some pathophysiological situations. Extracellular adenosine as a signaling molecule binds to adenosine receptors, which may trigger via their cognate trimeric G proteins different signaling pathways. In this way, adenosine regulates energy homeostasis and affects the function of various organs. Targeted pharmacological manipulations of specific adenosine receptor subtypes or enzymes involved in its metabolism can potentially be used for therapeutic purposes. PMID:26738245

  18. Asymptomatic myocardial ischemia following cold provocation

    SciTech Connect

    Shea, M.J.; Deanfield, J.E.; deLandsheere, C.M.; Wilson, R.A.; Kensett, M.; Selwyn, A.P.

    1987-09-01

    Cold is thought to provoke angina in patients with coronary disease either by an increase in myocardial demand or an increase in coronary vascular resistance. We investigated and compared the effects of cold pressor stimulation and symptom-limited supine bicycle exercise on regional myocardial perfusion in 35 patients with stable angina and coronary disease and in 10 normal subjects. Regional myocardial perfusion was assessed with positron emission tomography and rubidium-82. Following cold pressor stimulation 24 of 35 patients demonstrated significant abnormalities of regional myocardial perfusion with reduced cation uptake in affected regions of myocardium: 52 +/- 9 to 43 +/- 9 (p less than 0.001 vs normal subjects). Among these 24 patients only nine developed ST depression and only seven had angina. In contrast, 29 of 35 patients underwent supine exercise, and abnormal regional myocardial perfusion occurred in all 29, with a reduction in cation intake from 48 +/- 10 to 43 +/- 14 (p less than 0.001 vs normal subjects). Angina was present in 27 of 29 and ST depression in 25 of 29. Although the absolute decrease in cation uptake was somewhat greater following cold as opposed to exercise, the peak heart rate after cold was significantly lower than that after exercise (82 +/- 12 vs 108 +/- 16 bpm, p less than 0.05). Peak systolic blood pressures after cold and exercise were similar (159 +/- 24 vs 158 +/- 28). Thus, cold produces much more frequent asymptomatic disturbances of regional myocardial perfusion in patients with stable angina and coronary disease than is suggested by pain or ECG changes.

  19. Sitagliptin attenuates sympathetic innervation via modulating reactive oxygen species and interstitial adenosine in infarcted rat hearts

    PubMed Central

    Lee, Tsung-Ming; Chen, Wei-Ting; Yang, Chen-Chia; Lin, Shinn-Zong; Chang, Nen-Chung

    2015-01-01

    We investigated whether sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, attenuates arrhythmias through inhibiting nerve growth factor (NGF) expression in post-infarcted normoglycemic rats, focusing on adenosine and reactive oxygen species production. DPP-4 bound adenosine deaminase has been shown to catalyse extracellular adenosine to inosine. DPP-4 inhibitors increased adenosine levels by inhibiting the complex formation. Normoglycemic male Wistar rats were subjected to coronary ligation and then randomized to either saline or sitagliptin in in vivo and ex vivo studies. Post-infarction was associated with increased oxidative stress, as measured by myocardial superoxide, nitrotyrosine and dihydroethidium fluorescent staining. Measurement of myocardial norepinephrine levels revealed a significant elevation in vehicle-treated infarcted rats compared with sham. Compared with vehicle, infarcted rats treated with sitagliptin significantly increased interstitial adenosine levels and attenuated oxidative stress. Sympathetic hyperinnervation was blunted after administering sitagliptin, as assessed by immunofluorescent analysis and western blotting and real-time quantitative RT-PCR of NGF. Arrhythmic scores in the sitagliptin-treated infarcted rats were significantly lower than those in vehicle. Ex vivo studies showed a similar effect of erythro-9-(2-hydroxy-3-nonyl) adenine (an adenosine deaminase inhibitor) to sitagliptin on attenuated levels of superoxide and NGF. Furthermore, the beneficial effects of sitagliptin on superoxide anion production and NGF levels can be reversed by 8-cyclopentyl-1,3-dipropulxanthine (adenosine A1 receptor antagonist) and exogenous hypoxanthine. Sitagliptin protects ventricular arrhythmias by attenuating sympathetic innervation via adenosine A1 receptor and xanthine oxidase-dependent pathways, which converge through the attenuated formation of superoxide in the non-diabetic infarcted rats. PMID:25388908

  20. Magnetic resonance imaging in patients with unstable angina: comparison with acute myocardial infarction and normals

    SciTech Connect

    Ahmad, M.; Johnson, R.F. Jr.; Fawcett, H.D.; Schreiber, M.H.

    1988-09-01

    The role of magnetic resonance imaging in characterizing normal, ischemic and infarcted segments of myocardium was examined in 8 patients with unstable angina, 11 patients with acute myocardial infarction, and 7 patients with stable angina. Eleven normal volunteers were imaged for comparison. Myocardial segments in short axis magnetic resonance images were classified as normal or abnormal on the basis of perfusion changes observed in thallium-201 images in 22 patients and according to the electrocariographic localization of infarction in 4 patients. T2 relaxation time was measured in 57 myocardial segments with abnormal perfusion (24 with reversible and 33 with irreversible perfusion changes) and in 25 normally perfused segments. T2 measurements in normally perfused segments of patients with acute myocardial infarction, unstable angina and stable angina were within normal range derived from T2 measurements in 48 myocardial segments of 11 normal volunteers (42 +/- 10 ms). T2 in abnormal myocardial segments of patients with stable angina also was not significantly different from normal. T2 of abnormal segments in patients with unstable angina (64 +/- 14 in reversibly ischemic and 67 +/- 21 in the irreversibly ischemic segments) was prolonged when compared to normal (p less than 0.0001) and was not significantly different from T2 in abnormal segments of patients with acute myocardial infarction (62 +/- 18 for reversibly and 66 +/- 11 for irreversibly ischemic segments). The data indicate that T2 prolongation is not specific for acute myocardial infarction and may be observed in abnormally perfused segments of patients with unstable angina.

  1. 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.

  2. Purine metabolism in adenosine deaminase deficiency.

    PubMed Central

    Mills, G C; Schmalstieg, F C; Trimmer, K B; Goldman, A S; Goldblum, R M

    1976-01-01

    Purine and pyrimidine metabolites were measured in erythrocytes, plasma, and urine of a 5-month-old infant with adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) deficiency. Adenosine and adenine were measured using newly devised ion exchange separation techniques and a sensitive fluorescence assay. Plasma adenosine levels were increased, whereas adenosine was normal in erythrocytes and not detectable in urine. Increased amounts of adenine were found in erythrocytes and urine as well as in the plasma. Erythrocyte adenosine 5'-monophosphate and adenosine diphosphate concentrations were normal, but adenosine triphosphate content was greatly elevated. Because of the possibility of pyrimidine starvation, pyrimidine nucleotides (pyrimidine coenzymes) in erythrocytes and orotic acid in urine were measured. Pyrimidine nucleotide concentrations were normal, while orotic acid was not detected. These studies suggest that the immune deficiency associated with adenosine deaminase deficiency may be related to increased amounts of adenine, adenosine, or adenine nucleotides. PMID:1066699

  3. Cardiac myocyte–secreted cAMP exerts paracrine action via adenosine receptor activation

    PubMed Central

    Sassi, Yassine; Ahles, Andrea; Truong, Dong-Jiunn Jeffery; Baqi, Younis; Lee, Sang-Yong; Husse, Britta; Hulot, Jean-Sébastien; Foinquinos, Ariana; Thum, Thomas; Müller, Christa E.; Dendorfer, Andreas; Laggerbauer, Bernhard; Engelhardt, Stefan

    2014-01-01

    Acute stimulation of cardiac β-adrenoceptors is crucial to increasing cardiac function under stress; however, sustained β-adrenergic stimulation has been implicated in pathological myocardial remodeling and heart failure. Here, we have demonstrated that export of cAMP from cardiac myocytes is an intrinsic cardioprotective mechanism in response to cardiac stress. We report that infusion of cAMP into mice averted myocardial hypertrophy and fibrosis in a disease model of cardiac pressure overload. The protective effect of exogenous cAMP required adenosine receptor signaling. This observation led to the identification of a potent paracrine mechanism that is dependent on secreted cAMP. Specifically, FRET-based imaging of cAMP formation in primary cells and in myocardial tissue from murine hearts revealed that cardiomyocytes depend on the transporter ABCC4 to export cAMP as an extracellular signal. Extracellular cAMP, through its metabolite adenosine, reduced cardiomyocyte cAMP formation and hypertrophy by activating A1 adenosine receptors while delivering an antifibrotic signal to cardiac fibroblasts by A2 adenosine receptor activation. Together, our data reveal a paracrine role for secreted cAMP in intercellular signaling in the myocardium, and we postulate that secreted cAMP may also constitute an important signal in other tissues. PMID:25401477

  4. Adenosine-Associated Delivery Systems

    PubMed Central

    Kazemzadeh-Narbat, Mehdi; Annabi, Nasim; Tamayol, Ali; Oklu, Rahmi; Ghanem, Amyl; Khademhosseini, Ali

    2016-01-01

    Adenosine is a naturally occurring purine nucleoside in every cell. Many critical treatments such as modulating irregular heartbeat (arrhythmias), regulation of central nervous system (CNS) activity, and inhibiting seizural episodes can be carried out using adenosine. Despite the significant potential therapeutic impact of adenosine and its derivatives, the severe side effects caused by their systemic administration have significantly limited their clinical use. In addition, due to adenosine’s extremely short half-life in human blood (less than 10 s), there is an unmet need for sustained delivery systems to enhance efficacy and reduce side effects. In this paper, various adenosine delivery techniques, including encapsulation into biodegradable polymers, cell-based delivery, implantable biomaterials, and mechanical-based delivery systems, are critically reviewed and the existing challenges are highlighted. PMID:26453156

  5. Post-Coronary Artery Bypass Grafting Myocardial Ischemia Caused by an Overgrown Left Internal Thoracic Artery Side Branch

    PubMed Central

    Kim, Eung Re; Oh, Se Jin; Kang, Hyun-Jae; Kim, Ki-Bong

    2014-01-01

    We present a patient who developed recurrent angina after coronary artery bypass grafting (CABG). Myocardial single-photon emission computed tomography (SPECT) demonstrated deterioration in the myocardial perfusion, and coronary angiography revealed an overgrown side branch of the grafted left internal thoracic artery (ITA); otherwise, there were no significant changes compared with previous imaging studies obtained after the CABG. After percutaneous embolization of the grafted left ITA side branch, the angina was resolved and myocardial SPECT showed improved perfusion. PMID:25346902

  6. Cardiac PET perfusion tracers: current status and future directions.

    PubMed

    Maddahi, Jamshid; Packard, René R S

    2014-09-01

    PET myocardial perfusion imaging (MPI) is increasingly being used for noninvasive detection and evaluation of coronary artery disease. However, the widespread use of PET MPI has been limited by the shortcomings of the current PET perfusion tracers. The availability of these tracers is limited by the need for an onsite ((15)O water and (13)N ammonia) or nearby ((13)N ammonia) cyclotron or commitment to costly generators ((82)Rb). Owing to the short half-lives, such as 76 seconds for (82)Rb, 2.06 minutes for (15)O water, and 9.96 minutes for (13)N ammonia, their use in conjunction with treadmill exercise stress testing is either not possible ((82)Rb and (15)O water) or not practical ((13)N ammonia). Furthermore, the long positron range of (82)Rb makes image resolution suboptimal and its low myocardial extraction limits its defect resolution. In recent years, development of an (18)F-labeled PET perfusion tracer has gathered considerable interest. The longer half-life of (18)F (109 minutes) would make the tracer available as a unit dose from regional cyclotrons and allow use in conjunction with treadmill exercise testing. Furthermore, the short positron range of (18)F would result in better image resolution. Flurpiridaz F 18 is by far the most thoroughly studied in animal models and is the only (18)F-based PET MPI radiotracer currently undergoing clinical evaluation. Preclinical and clinical experience with Flurpiridaz F 18 demonstrated a high myocardial extraction fraction, high image and defect resolution, high myocardial uptake, slow myocardial clearance, and high myocardial-to-background contrast that was stable over time-important properties of an ideal PET MPI radiotracer. Preclinical data from other (18)F-labeled myocardial perfusion tracers are encouraging. PMID:25234078

  7. The effect of systemic hypoxia on interstitial and blood adenosine, AMP, ADP and ATP in dog skeletal muscle

    PubMed Central

    Mo, F M; Ballard, H J

    2001-01-01

    We investigated the effect of moderate systemic hypoxia on the arterial, venous and interstital concentration of adenosine and adenine nucleotides in the neurally and vascularly isolated, constant-flow perfused gracilis muscles of anaesthetized dogs. Systemic hypoxia reduced arterial PO2 from 129 to 28 mmHg, venous PO2 from 63 to 23 mmHg, arterial pH from 7.43 to 7.36 and venous pH from 7.38 to 7.32. Neither arterial nor venous PCO2 were changed. Arterial perfusion pressure remained at 109 ± 8 mmHg for the first 5 min of hypoxia, then increased to 131 ± 11 mmHg by 9 min, and then decreased again throughout the rest of the hypoxic period. Arterial adenosine (427 ± 98 nm) did not change during hypoxia, but venous adenosine increased from 350 ± 52 to 518 ± 107 nm. Interstitial adenosine concentration did not increase (339 ± 154 nm in normoxia and 262 ± 97 nm in hypoxia). Neither arterial nor venous nor interstitial concentrations of adenine nucleotides changed significantly in hypoxia. Interstitial adenosine, AMP, ADP and ATP increased from 194 ± 40, 351 ± 19, 52 ± 7 and 113 ± 36 to 764 ± 140, 793 ± 119, 403 ± 67 and 574 ± 122 nm, respectively, during 2 Hz muscle contractions. Adenosine, AMP, ADP and ATP infused into the arterial blood did not elevate the interstitial concentration until the arterial concentration exceeded 10 μm. We conclude that the increased adenosine in skeletal muscle during systemic hypoxia is formed by the vascular tissue or the blood cells, and that adenosine is formed intracellularly by these tissues. On the other hand, adenosine formation takes place extracellularly in the interstitial space during muscle contractions. PMID:11600692

  8. Pulmonary ventilation/perfusion scan

    MedlinePlus

    V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan ... A pulmonary ventilation/perfusion scan is actually two tests. They may be done separately or together. During the perfusion scan, a health ...

  9. Evidence for control of adenosine metabolism in rat oxidative skeletal muscle by changes in pH

    PubMed Central

    Cheng, B; Essackjee, H C; Ballard, H J

    2000-01-01

    We investigated the effects of pH elevation or depression on adenosine output from buffer-perfused rat gracilis muscle, and kinetic properties of adenosine-forming enzymes, 5′-nucleotidase (5′N) and non-specific phosphatase (PT), and adenosine-removing enzymes, adenosine kinase (AK) and adenosine deaminase (AD), in homogenates of muscle. Depression of the perfusion buffer pH from 7.4 to 6.8, by addition of sodium acetate, reduced arterial perfusion pressure from 8.44 ± 1.44 to 7.33 ± 0.58 kPa, and increased adenosine output from 35 ± 5 to 56 ± 6 pmol min−1 (g wet wt muscle)−1 and AMP output from 1.8 ± 0.3 to 9.1 ± 3.9 pmol min−1 (g wet wt muscle)−1. Elevation of the buffer pH to 7.8, by addition of ammonium chloride, reduced arterial perfusion pressure from 8.74 ± 0.57 to 6.96 ± 1.37 kPa, and increased adenosine output from 25 ± 5 to 47 ± 8 pmol min−1 (g wet wt muscle)−1 and AMP output from 3.7 ± 1.1 to 24.6 ± 6.8 pmol min−1 (g wet wt muscle)−1. Activity of membrane-bound 5′N was an order of magnitude higher than that of either cytosolic 5′N or PT: pH depression reduced the Km of 5′N, which increased its capacity to form adenosine by 10–20% for every 0.5 unit decrease in pH within the physiological range. PT was only found in the membrane fraction: its contribution to extracellular adenosine formation increased from about 5% at pH 7.0 to about 15% at pH 8.0. Cytosolic 5′N had a low activity, which was unaffected by pH; the rate of intracellular adenosine formation was an order of magnitude lower than the rate of adenosine removal by adenosine kinase or adenosine deaminase, which were both exclusively intracellular enzymes. We conclude that (i) adenosine is formed in the extracellular compartment of rat skeletal muscle, principally by membrane-bound 5′N, where it is protected from enzymatic breakdown; (ii) adenosine is formed intracellularly at a very low rate, and is unlikely to leave the cell; (iii) enhanced adenosine

  10. Administration of intracoronary eptifibatide during ST-elevation myocardial infarction.

    PubMed

    Pinto, Duane S; Kirtane, Ajay J; Ruocco, Nicholas A; Deibele, Albert J; Shui, Amy; Buros, Jacki; Murphy, Sabina A; Gibson, C Michael

    2005-12-01

    Distal embolization of atherothrombotic material during primary percutaneous coronary intervention (PCI) is associated with impaired myocardial perfusion