Home About us Contact
|
Home About us Contact | ||
|
|
||
Myocardial Perfusion Imaging (myocardial + perfusion_imaging)
Selected AbstractsDiagnostic and Prognostic Value of Myocardial Perfusion Imaging in Patients with Known or Suspected Stable Coronary Artery DiseaseECHOCARDIOGRAPHY, Issue 6 2000Aman M. Amanullah M.D., Ph.D. Coronary artery disease is the leading cause of complications and death in the United States and other Western countries, and stress myocardial perfusion study is an important component of the clinical evaluation, stratification, and management. This imaging technique is a well-established modality and has been widely used for the past three decades. New quantitative techniques for the assessment of ventricular function using quantitative gated single-photon emission computed tomography in addition to myocardial perfusion will potentially enhance the role of nuclear cardiology in the management of these patients. This review summarizes the current knowledge of the diagnostic and prognostic uses of stress myocardial perfusion imaging using exercise and pharmacological stress in patients with stable coronary artery disease. [source] Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging in the Diagnosis of Left Main DiseaseCLINICAL CARDIOLOGY, Issue 12 2009Luis Afonso MD Background Left main disease (LMD), defined as , 50% lesion stenosis, occurs in 3% to 5% of patients undergoing catheterization. Limited data on the value of single-photon emission computed tomography (SPECT) imaging for diagnosis of LMD exists. Hypothesis This study sought to evaluate the diagnostic accuracy of SPECT imaging in the diagnosis of LMD. Methods A total of 74 consecutive patients with LMD, identified from our catheterization lab database (January 2003,December 2007) with gated exercise (15 patients) or adenosine (59 patients), thallium 201, or Tc-99m SPECT imaging within 6 months of index angiography were included. Group 1 (Gp 1) included 33 patients with isolated LMD. Group 2 (Gp 2) consisted of 41 patients with LMD and 1-vessel disease (6); LMD and 2-vessel disease (24); and LMD and 3-vessel disease (11). Results Reversible perfusion defects (PD) were absent in 6 (18%) of Gp 1 and 8 (20%) of Gp 2 patients. Among Gp 1 patients, PD in 1-vessel, 2-vessel, 3-vessel distribution were seen in 20 (61%), 5 (15%), and 2 (6%) patients respectively. In comparison, PD in 1-vessel, 2-vessel, 3-vessel distribution were observed in 20 (49%), 12 (29%), and 1 (2%) of Gp 2 patients respectively. Left main (LM) pattern was noted in 6 patients (Gp 1: 2, Gp 2: 4). Transient ischemic dilatation (TID) was encountered in 34 patients (Gp 1: 17, Gp 2: 17) and in 4 patients with normal perfusion scans. Conclusions These data represent the largest analysis of patients with "isolated" LMD. Approximately 19% of patients with LMD have no reversible PD on SPECT. While LM pattern is rare, 1-vessel distribution PD and TID represent the most frequent SPECT abnormalities. Copyright © 2009 Wiley Periodicals, Inc. [source] Myocardial perfusion imaging and cardiac events in a cohort of asymptomatic patients with diabetes living in southern FranceDIABETIC MEDICINE, Issue 4 2006A. Sultan Abstract Aims, To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with , 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. Methods, Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5,4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. Results, Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7,18.5)]. Low-density lipoprotein cholesterol , 3.35 mmol/l [OR (95% CI) = 7.3; 1.5,34.7] and age > median [OR (95% CI) = 6.0 (1.2,28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides , 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8,8.8)]. Conclusions, Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention. Diabet. Med. (2006) [source] Myocardial perfusion imaging in evaluation of undiagnosed acute chest painINTERNAL MEDICINE JOURNAL, Issue 9 2001J. C. Knott Abstract Myocardial perfusion imaging is a relatively new technique in the emergency department management of acute chest pain. With improved sensitivity and specificity compared to traditional methods of risk stratification, an abnormal scan rapidly identifies individuals with acute perfusion abnormalities and allows the appropriate utilization of limited resources. Conversely, a normal scan allows prompt hospital discharge and is associated with excellent outcomes both in the short and medium terms. Acute chest pain myocardial perfusion imaging has been demonstrated to alter patient management and disposition and its routine use results in decreased costs in the intermediate risk population. (Intern Med J 2001; 31: 544,546) [source] Myocardial perfusion imaging and cardiac events in a cohort of asymptomatic patients with diabetes living in southern FranceDIABETIC MEDICINE, Issue 4 2006A. Sultan Abstract Aims, To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with , 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. Methods, Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5,4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. Results, Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7,18.5)]. Low-density lipoprotein cholesterol , 3.35 mmol/l [OR (95% CI) = 7.3; 1.5,34.7] and age > median [OR (95% CI) = 6.0 (1.2,28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides , 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8,8.8)]. Conclusions, Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention. Diabet. Med. (2006) [source] Diagnostic and Prognostic Value of Myocardial Perfusion Imaging in Patients with Known or Suspected Stable Coronary Artery DiseaseECHOCARDIOGRAPHY, Issue 6 2000Aman M. Amanullah M.D., Ph.D. Coronary artery disease is the leading cause of complications and death in the United States and other Western countries, and stress myocardial perfusion study is an important component of the clinical evaluation, stratification, and management. This imaging technique is a well-established modality and has been widely used for the past three decades. New quantitative techniques for the assessment of ventricular function using quantitative gated single-photon emission computed tomography in addition to myocardial perfusion will potentially enhance the role of nuclear cardiology in the management of these patients. This review summarizes the current knowledge of the diagnostic and prognostic uses of stress myocardial perfusion imaging using exercise and pharmacological stress in patients with stable coronary artery disease. [source] Nuclear Cardiology in the Evaluation of Acute Chest Pain in the Emergency DepartmentECHOCARDIOGRAPHY, Issue 6 2000Brian G. Abbott M.D. Only a minority of patients presenting to the emergency department (ED) with acute chest pain will eventually be diagnosed with an acute coronary syndrome. The majority will have an electrocardiogram that is normal or nondiagnostic for acute myocardial ischemia or infarction. Typically, these patients are admitted to exclude myocardial infarction despite a very low incidence of coronary artery disease. However, missed myocardial infarctions in patients who are inadvertently sent home from the ED have significant adverse outcomes and associated legal consequences. This leads to a liberal policy to admit patients with chest pain, presenting a substantial burden in terms of cost and resources. Many centers have developed chest pain centers, using a wide range of diagnostic modalities to deal with this dilemma. We discuss the methods currently available to exclude myocardial ischemia and infarction in the ED, focusing on the use of myocardial perfusion imaging as both an adjunct and an alternative to routine testing. We review the available literature centering on the ED evaluation of acute chest pain and then propose an algorithm for the practical use of nuclear cardiology in this setting. [source] Myocardial perfusion imaging in evaluation of undiagnosed acute chest painINTERNAL MEDICINE JOURNAL, Issue 9 2001J. C. Knott Abstract Myocardial perfusion imaging is a relatively new technique in the emergency department management of acute chest pain. With improved sensitivity and specificity compared to traditional methods of risk stratification, an abnormal scan rapidly identifies individuals with acute perfusion abnormalities and allows the appropriate utilization of limited resources. Conversely, a normal scan allows prompt hospital discharge and is associated with excellent outcomes both in the short and medium terms. Acute chest pain myocardial perfusion imaging has been demonstrated to alter patient management and disposition and its routine use results in decreased costs in the intermediate risk population. (Intern Med J 2001; 31: 544,546) [source] Ultrafast imaging: Principles, pitfalls, solutions, and applicationsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2010Jeffrey Tsao PhD Abstract Ultrafast MRI refers to efficient scan techniques that use a high percentage of the scan time for data acquisition. Often, they are used to achieve short scan duration ranging from sub-second to several seconds. Alternatively, they may form basic components of longer scans that may be more robust or have higher image quality. Several important applications use ultrafast imaging, including real-time dynamic imaging, myocardial perfusion imaging, high-resolution coronary imaging, functional neuroimaging, diffusion imaging, and whole-body scanning. Over the years, echo-planar imaging (EPI) and spiral imaging have been the main ultrafast techniques, and they will be the focus of the review. In practice, there are important challenges with these techniques, as it is easy to push imaging speed too far, resulting in images of a nondiagnostic quality. Thus, it is important to understand and balance the trade-off between speed and image quality. The purpose of this review is to describe how ultrafast imaging works, the potential pitfalls, current solutions to overcome the challenges, and the key applications. J. Magn. Reson. Imaging 2010;32:252,266. © 2010 Wiley-Liss, Inc. [source] Comparison of dual to single contrast bolus magnetic resonance myocardial perfusion imaging for detection of significant coronary artery diseaseJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2010Jan G.J. Groothuis MD Abstract Purpose: To investigate the incremental diagnostic value of dual-bolus over single-contrast-bolus first pass magnetic resonance myocardial perfusion imaging (MR-MPI) for detection of significant coronary artery disease (CAD). Materials and Methods: Patients (n = 49) with suspected CAD underwent first pass adenosine stress and rest MR-MPI and invasive coronary angiography (CA). Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) was injected with a prebolus (1 mL) and a large bolus (0.1 mmol/kg). For the single-bolus technique, the arterial input function (AIF) was obtained from the large-contrast bolus. For the dual-bolus technique, the AIF was reconstructed from the prebolus. Absolute myocardial perfusion was calculated by Fermi-model constrained deconvolution. Receiver operating characteristic (ROC) analysis was used to investigate diagnostic accuracy of MR myocardial perfusion imaging for detection of significant CAD on CA at vessel-based analysis. Results: The area under the curve (AUC) of the minimal stress perfusion value for the detection of significant CAD using the single-bolus and dual-bolus technique was 0.85 ± 0.04 (95% confidence interval [CI], 0.77,0.93) and 0.77 ± 0.05 (95% CI, 0.67,0.86), respectively. Conclusion: In this study the dual-bolus technique had no incremental diagnostic value over single-bolus technique for detection of significant CAD with the used contrast concentrations. J. Magn. Reson. Imaging 2010;32:88,93. © 2010 Wiley-Liss, Inc. [source] SCREENING FOR CARDIOVASCULAR DISEASE IN PATIENTS WITH ADVANCED CHRONIC KIDNEY DISEASEJOURNAL OF RENAL CARE, Issue 2010Rajan Sharma BSc SUMMARY Cardiovascular disease remains the major cause of mortality and morbidity in patients with advanced chronic kidney disease (CKD) and after renal transplantation. The mechanisms for cardiotoxicity are multiple. Identifying high-risk patients remains a challenge. Given, the poor long-term outcome of dialysis patients who do not receive renal transplantation and the lower supply of donor kidneys relative to demand, optimal selection of renal transplantation candidates is crucial. This requires a clear understanding of the validity of cardiac tests in this patient group. This paper explores the strengths and weaknesses of currently available diagnostic tools in patients with advanced CKD. Echocardiography is very useful for the detection of cardiomyopathy and prognosis. Stress echocardiography, myocardial perfusion imaging and coronary angiography are the best tools for the assessment of coronary artery disease. All predict outcome. No single gold standard investigation exists. At present, there is not an optimal technique for predicting sudden cardiac death in this patient group. Ultimately, the choice of cardiac test will always be determined by patient preference, local expertise and availability. [source] Systolic 3D first-pass myocardial perfusion MRI: Comparison with diastolic imaging in healthy subjectsMAGNETIC RESONANCE IN MEDICINE, Issue 4 2010Taehoon Shin Abstract Three-dimensional (3D) first-pass myocardial perfusion imaging (MPI) is a promising alternative to conventional two-dimensional multislice MPI due to its contiguous spatial coverage that is beneficial for estimating the size of perfusion defects. Data acquisition at mid-diastole is a typical choice for 3D MPI yet is sensitive to arrhythmia and variations in R-R interval that are common in cardiac patients. End systole is the second longest quiescent cardiac phase and is known to be less sensitive to the R-R variability. Therefore, 3D MPI with systolic acquisition may be advantageous in patients with severe arrhythmia once it is proven to be comparable to diastolic MPI in subjects with negligible R-R variation. In this work, we demonstrate the feasibility of 3D MPI with systolic data acquisition in five healthy subjects. We performed 3D MPI experiments in which 3D perfusion data were acquired at both end-systole and mid-diastole of every R-R interval and analyzed the similarity between resulting time intensity curves (TIC) from the two data sets. The correlation between systolic and diastolic TICs was extremely high (mean = 0.9841; standard deviation = 0.0166), and there was a significant linear correlation between the two time intensity curve upslopes and peak enhancements (P < 0.001). Magn Reson Med 63:858,864, 2010. © 2010 Wiley-Liss, Inc. [source] Myocardial perfusion MRI with sliding-window conjugate-gradient HYPRMAGNETIC RESONANCE IN MEDICINE, Issue 4 2009Lan Ge Abstract First-pass perfusion MRI is a promising technique for detecting ischemic heart disease. However, the diagnostic value of the method is limited by the low spatial coverage, resolution, signal-to-noise ratio (SNR), and cardiac motion-related image artifacts. In this study we investigated the feasibility of using a method that combines sliding window and CG-HYPR methods (SW-CG-HYPR) to reduce the acquisition window for each slice while maintaining the temporal resolution of one frame per heartbeat in myocardial perfusion MRI. This method allows an increased number of slices, reduced motion artifacts, and preserves the relatively high SNR and spatial resolution of the "composite images." Results from eight volunteers demonstrate the feasibility of SW-CG-HYPR for accelerated myocardial perfusion imaging with accurate signal intensity changes of left ventricle blood pool and myocardium. Using this method the acquisition time per cardiac cycle was reduced by a factor of 4 and the number of slices was increased from 3 to 8 as compared to the conventional technique. The SNR of the myocardium at peak enhancement with SW-CG-HYPR (13.83 ± 2.60) was significantly higher (P < 0.05) than the conventional turbo-FLASH protocol (8.40 ± 1.62). Also, the spatial resolution of the myocardial perfection images was significantly improved. SW-CG-HYPR is a promising technique for myocardial perfusion MRI. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] Perfusion MRI with radial acquisition for arterial input function assessment,MAGNETIC RESONANCE IN MEDICINE, Issue 5 2007Eugene G. Kholmovski Abstract Quantification of myocardial perfusion critically depends on accurate arterial input function (AIF) and tissue enhancement curves (TECs). Except at low doses, the AIF is inaccurate because of the long saturation recovery time (SRT) of the pulse sequence. The choice of dose and SRT involves a trade-off between the accuracy of the AIF and the signal-to-noise ratio (SNR) of the TEC. Recent methods to resolve this trade-off are based on the acquisition of two data sets: one to accurately estimate the AIF, and one to find the high-SNR TEC. With radial k -space sampling, a set of images with varied SRTs can be reconstructed from the same data set, allowing an accurate assessment of the AIF and TECs, and their conversion to contrast agent (CA) concentration. This study demonstrates the feasibility of using a radial acquisition for quantitative myocardial perfusion imaging. Magn Reson Med 57:821,827, 2007. © 2007 Wiley-Liss, Inc. [source] The Effect of Acute Psychological Stress on QT Dispersion in Patients with Coronary Artery DiseasePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2009MUSTAFA HASSAN M.D. Background: An acute psychological stress can precipitate ventricular arrhythmias and sudden cardiac death in patients with coronary artery disease (CAD). However, the physiologic mechanisms by which these effects occur are not entirely clear. Mental stress-induced myocardial ischemia occurs in a significant percentage of the CAD population. It is unknown if the proarrhythmic effects of psychological stress are mediated through the development of myocardial ischemia. Objectives: To examine the effects of psychological stress on QT dispersion (QTd) among CAD patients and whether these effects are mediated via the development of myocardial ischemia. Methods: Psychological stress was induced using a public speaking task. Twelve-lead electrocardiograms (ECG) were recorded at rest, during mental stress, and during recovery. QTd was calculated as the difference between the longest and the shortest QT interval in the 12-lead ECG. Rest-stress myocardial perfusion imaging was also performed to detect mental stress-induced myocardial ischemia. Results: Mental stress induced a significant increase in QTd compared to the resting condition (P < 0.001). This effect persisted beyond the first 10 minutes of recovery (P < 0.001). QTd was significantly associated with the development of mental stress ischemia with ischemic patients having significantly higher QTd during mental stress than nonischemic patients (P = 0.006). This finding remained significant after controlling for possible confounding factors (P = 0.01). Conclusion: An acute psychological stress induces a significant increase in QTd, which persists for more than 10 minutes after the cessation of the stressor. This effect seems to be, at least partially, mediated by the development of mental stress-induced myocardial ischemia. [source] Lipid Risk Factor Correlates of Ischemic Heart Disease as Diagnosed by Myocardial Perfusion ScintigraphyPREVENTIVE CARDIOLOGY, Issue 4 2000Kevin A. Bybee MD Patients with known coronary artery disease frequently change their lifestyles (e.g., diet, exercise, and smoking habit) after the diagnosis is made. Such changes can alter lipid risk factor levels and obscure etiologic risk factor associations with the presence of coronary artery disease. It is therefore preferable to determine the contribution of potential risk factors before the diagnosis of coronary artery disease has been established. In this trial, we used stress nuclear myocardial perfusion imaging to diagnose coronary artery disease in patients presenting for evaluation of chest pain. Two groups of age- and sex-matched patients were identified: a normal group (patients with no evidence of coronary artery disease), and an abnormal group (patients whose scans indicated the presence of significant coronary artery disease due to either fixed or reversible perfusion defects). Blood samples were drawn before scanning and analyzed for lipid risk factors. Compared to the normal group, the abnormal group had higher levels of triglycerides (189±91 vs. 135±51 mg/dL, p=0.003), lower levels of high density lipoprotein cholesterol (39±9 vs. 45±14 mg/dL, p=0.037), and higher levels of small, dense low density lipoprotein (LDL3) (42±18 vs. 32±13 mg/dL, p=0.007). Total cholesterol, low density lipoprotein, and lipoprotein(a) levels were similar between groups. These findings suggest that ischemic heart disease, as assessed by myocardial perfusion scintigraphy, is more closely associated with the low high density lipoprotein/high triglyceride syndrome than with increased low density lipoprotein or total cholesterol levels. [source] Myocardial Perfusion Profile in a Young Population With and Without Known Coronary Artery Disease: Comparison by GenderCLINICAL CARDIOLOGY, Issue 2 2010Nili Zafrir MD Background More and more young people are being referred for evaluation or screening for coronary artery disease (CAD). However, the value of myocardial perfusion imaging (MPI) in this population is unclear, especially in the absence of symptoms. Methods The study sample included 1765 consecutive patients less than 51 years old who were referred to a major medical center for stress/rest MPI study. Clinical and MPI variables were compared between patients with and without known CAD, by gender. Results There were 1346 (76%) men and 419 (24%) women of mean age 44 ± 6 years; 461 (26%) had known CAD. Stress-induced ischemia was detected in 321 patients (18.2%) and significant ischemia in 131 (7.4%); there was no difference in the rate or severity of ischemia by presence of symptoms. Among those without known CAD, the rate of stress-induced ischemia by MPI was significantly lower in women than men. On logistic regression analysis, the independent predictors of ischemia in men were high cholesterol, diabetes, angina during stress testing, ST depression, and smoking (P<.0001); and in women, the independent predictors were diabetes and high cholesterol. Conclusion Known CAD and stress-induced ischemia are significantly more prevalent in young men than in young women, irrespective of risk factors. The independent predictors of ischemia differ between men and women. Copyright © 2010 Wiley Periodicals, Inc. [source] To what degree is amelioration of angina following coronary revascularization associated with improvement in myocardial perfusion?CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2006Allan Johansen Summary Objective:, To examine the association between changes in chest pain and changes in perfusion following revascularization as assessed by clinical evaluation and myocardial perfusion imaging (MPI) in patients with stable angina. Design:, In a prospective series of 380 patients (58·8 ± 8·8 years) referred to angiography because of known or suspected stable angina, changes in chest discomfort and changes in perfusion after 2 years were assessed in 144 patients, who underwent revascularization, and 236, who did not. The decision to treat invasively was made without knowledge of the result of MPI. Results:, In revascularized patients, the presence of typical/atypical angina was reduced from 93% to 36% and the improvement was associated with improvement in perfusion. A small improvement in perfusion induced a high frequency of change from angina to no pain, whereas a further reduction caused little extra change. In non-revascularized patients the change in chest discomfort was not related to changes in perfusion, which were rarely present. Conclusion:, Alleviation of chest discomfort 2 years after revascularization is associated with improvements in perfusion. This association appeared to be an all-or-nothing phenomenon. Non-revascularized patients also exhibited improvements in chest discomfort despite insignificant changes in perfusion. [source] Arterial concentration of 99mTc-sestamibi at rest, during peak exercise and after dipyridamole infusionCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 6 2004Niels Peter Rønnow Sand Summary Tracers for myocardial perfusion imaging during stress should not only have high cardiac uptake but they should also have a fast blood clearance to prevent myocardial tracer uptake after the ischaemic stimulus. The present study characterize the early phase of the arterial 99mTc-sestamibi (MIBI) time-activity curve after venous bolus injection at rest, during peak exercise and after dipyridamole infusion. We included 11 patients undergoing angioplasty for one-vessel disease (rest study) and 20 patients evaluated for the detection of haemodynamic significant coronary stenoses by 99mTc-sestamibi single photon emission computed tomography (SPECT) using either bicycle exercise testing (10 patients) or standard dipyridamole testing (10 patients). Arterial blood samples of 1 ml were taken from the left femoral artery (rest study) or the right radial artery (exercise and dipyridamole studies) every 5 s during the first 5 min postinjection. In the exercise and the dipyridamole studies blood sampling were extended to include blood samples every 5 min 5,30 min postinjection. Peak MIBI concentration was lower and decrease in concentration slower after tracer injection during exercise than during dipyridamole stress testing. This may cause an underestimation of perfusion defects during exercise because of MIBI uptake after the ischaemic stimulus. The implications of the study not only refer to the choice of stress modality when using MIBI. This study also underlines the importance of considering early blood clearance in addition to regional myocardial tracerkinetic aspects such as myocardial extraction fraction when new tracers are introduced. [source] | ||||||||||||||||||||||