technetium-tc-99m-tetrofosmin and Heart-Diseases

Based on superior image quality, more accurate gated images, and lower radiation exposure to patients, Technetium-99m (Tc-99m) based tracers are preferred over Thallium-201 for SPECT myocardial perfusion imaging. The two Tc-99m tracers, sestamibi and tetrofosmin, have many similar characteristics but there are differences in blood and liver clearance rates, as well as the recommended time after injection for imaging to achieve optimal image quality. Because published peer-reviewed studies examining optimal times between injection and imaging are limited, it can be difficult to identify evidence-based opportunities to optimize imaging protocols. Using systematic literature review methods, this study was designed to identify and consolidate the available evidence on the use of sestamibi compared to tetrofosmin for variable injection to imaging times in regard to test efficiency, including test length and re-scan rates, and image quality, including overall quality and cardiac to extra-cardiac ratios. The composite of this data shows that earlier imaging with tetrofosmin is equivalent to later imaging with sestamibi when assessing subjective image quality or when quantifying heart-to-extra-cardiac ratios. Image quality and heart-to-extra-cardiac ratios comparing early versus later imaging with tetrofosmin were comparable if not equivalent to each other. The equivalency of the imaging quality occurs with 15 minutes (on average) earlier imaging compared to sestamibi and 30 minutes compared to standard time tetrofosmin. The subjective findings of equivalent image quality are also shown with objective measurements of heart-to-extra-cardiac ratios. In this review, the significantly shorter injection-to-acquisition times with tetrofosmin compared to sestamibi resulted in better efficiency and less waiting times for patients; in addition, significantly higher re-scan rates with sestamibi compared to tetrofosmin due to hepatic activity contributed to better throughput with tetrofosmin.

Topics: Heart Diseases; Humans; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Technetium Tc 99m Sestamibi; Time Factors; Tomography, Emission-Computed, Single-Photon

Factors affecting the accuracy of left ventricular ejection fraction (LVEF) quantification using automated quantitative gated SPECT have not been adequately investigated in patients in the clinical setting. Therefore, the authors studied the effect of defect size and Tc-99m tetrofosmin dose on the accuracy of LVEF calculation using the automated QGS program.. Thirty-two consecutive patients underwent gated rest and stress myocardial perfusion SPECT after administration of 8 and 27 mCi Tc-99m tetrofosmin, respectively. The LVEF was obtained for both the rest and stress studies using the QGS program and compared with the LVEF obtained using quantitative echocardiography performed within 2 weeks. Myocardial perfusion defects were recorded as scarring, ischemia, or mixed scarring and ischemia in 12 left ventricular segments. The defect size was evaluated by adding the number of affected segments.. The mean LVEF calculated using high-dose stress QGS, low-dose rest QGS, and echocardiography was 49.2% +/- 15%, 46.2% +/- 17% and 48.7% +/- 16.9% respectively, with no statistically significant differences. The LVEF obtained using high-dose stress QGS correlated better with echocardiography than did that obtained using low-dose rest QGS (r = 0.86 versus 0.76). In addition, when the high-dose stress LVEF in the 14 patients with normal myocardial perfusion was compared with that in 11 patients who had one- or two-segment perfusion defects, and 7 patients who had perfusion defects in > or = three segments, there was good correlation with echocardiography in the three patient groups (r = 0.85, 0.88, and 0.91, respectively).. Myocardial perfusion defects do not affect the accuracy of LVEF calculation using automated QGS. High-dose gated myocardial SPECT demonstrated better correlation with quantitative echocardiography LVEF results.

Topics: Adult; Aged; Dipyridamole; Dose-Response Relationship, Drug; Female; Gated Blood-Pool Imaging; Heart Diseases; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Reproducibility of Results; Sensitivity and Specificity; Statistics as Topic; Stress, Physiological; Stroke Volume; Ultrasonography; Ventricular Dysfunction, Left

Left ventricular mass is an important determinant of diagnosis and prognosis in patients with heart disease. The aim of the present study was to validate measurement of the left ventricular mass index (LVMI) by quantitative gated myocardial SPECT (QGS) with 99mTc-tetrofosmin by comparing it with echocardiography.. QGS and M-mode echocardiography (Echo) were performed within one month of each other in 179 patients. M-mode echocardiography was carried out according to Devereux's method. QGS images were acquired one hour after injection of 99Tc-tetrofosmin at rest. Myocardial volume was defined as the volume between the endocardial and epicardial surface in the end-diastolic phase. LVMI (g/m2) was defined as myocardial volume divided by myocardial specific density and corrected for body surface area. QGS LVMI measurements were performed twice by the same observer and independently by two different observers. Regional hypoperfusion in the group of patients with old myocardial infarction (n = 26) was evaluated semiquantitatively on the basis of the total defect score on the resting 99mTc-tetrofosmin SPECT images.. Among the patients as a whole QGS LVMI was significantly correlated with Echo LVMI (r = 0.96, p < 0.001). Intra-observer and inter-observer analyses showed significant reproducibility (r = 0.99 and r = 0.98, respectively, p < 0.001). In the patients with old myocardial infarction, but QGS LVMI was significantly lower than Echo LVMI (p < 0.001), and the magnitude of the underestimation was closely related to the severity of the perfusion defect on the resting SPECT images.. Measurements of LVMI by 99mTc-tetrofosmin QGS are reproducible and consistent with echocardiograpic estimates. Underestimation in patients with severe perfusion defects must be taken into consideration.

Topics: Echocardiography; Feasibility Studies; Female; Gated Blood-Pool Imaging; Heart Diseases; Heart Ventricles; Humans; Male; Middle Aged; Observer Variation; Organ Size; Organophosphorus Compounds; Organotechnetium Compounds; Radiography; Radiopharmaceuticals; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon; Ventricular Dysfunction, Left

There are no large studies available to guide the selection of thallium (Tl), methoxyisobutylisonitrile (MIBI) or tetrofosmin (Tf) for myocardial perfusion imaging. Our objective was to compare the technical and clinical performance of the three in routine clinical practice. We randomised 2,560 patients to receive Tl, MIBI or Tf. A 1-day stress/rest protocol was used for MIBI and Tf. Tracer uptake was scored using a 17-segment model, quality and artefact scores were assigned, and ratios of heart (H), liver (L), subdiaphragmatic (S) and lung activity were measured. Mean quality scores (stress/rest) were Tl 2.13/2.16, MIBI 2.18/2.39, Tf 2.18/2.42 ( P=ns stress and <0.00001 rest). For attenuation artefact, Tl>MIBI=Tf ( P<0.05) and for low-count artefact Tl>MIBI>Tf ( P<0.001). For H/S, Tl>MIBI=Tf, for H/L Tl>MIBI=Tf, and for H/lung Tl

Topics: Adenosine; Artifacts; Coronary Disease; Cross-Sectional Studies; Dobutamine; Exercise Test; Heart; Heart Diseases; Humans; Myocardium; Organophosphorus Compounds; Organotechnetium Compounds; Quality Control; Radiography; Radionuclide Imaging; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Technetium Tc 99m Sestamibi; Thallium; United Kingdom

Many quantitative analysis methods for myocardial perfusion studies require as a central step a comparison with a 'normal' or average density distribution map or reference image. It has been recognized, however, that the normal distribution can be affected by patient attributes, including sex and weight or body habitus, and by acquisition attributes, including the choice of tracer and the position of the patient during imaging. Some authors have proposed separate reference images for the sexes and the tracer. This approach fails if a large number of binary attributes have to be considered, since one would need 2" reference images for each attribute. The problem is compounded when continuous attributes (e.g. age and weight) are included, especially if the approach is to average separate homogeneous groups for each attribute. We propose to create case-specific reference images for the interpretation of myocardial perfusion studies by creating a model based on the influence of each attribute. From a non-homogeneous population of normal cases, or cases presumed to be normal on the basis of the Diamond and Forrester stratification, the effect of patient and study attributes on the density distribution in the stress image and the density differences between rest and stress images were computed. The effects are computed by multi-linear regression, to account for cross-correlation. Significance is assigned on the basis of a partial Fisher test. The data are myocardial perfusion images matched in 3D to a template by an elastic transformation. Even though there was some cross-correlation in the data, we were able to show independent effects of sex, position (prone or supine), age, weight, tracer combination and stress method (exercise, persantine and adenosine). Taken as a whole, the multi-linear regression demonstrated a significant effect in 72% of the pixels within the myocardial volume. In addition, the distribution predicted by the model was equivalent to average images from homogeneous matched groups. In conclusion, our approach makes it possible to produce case-specific reference images without the need for multiple homogeneous large groups to produce averages for each possible patient or study attribute.

Topics: Adenosine; Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Dipyridamole; Exercise Test; Female; Heart; Heart Diseases; Humans; Least-Squares Analysis; Male; Middle Aged; Models, Cardiovascular; Models, Statistical; Organophosphorus Compounds; Organotechnetium Compounds; Posture; Radionuclide Imaging; Radiopharmaceuticals; Reference Values; Regression Analysis; Sex Factors; Technetium Tc 99m Sestamibi; Thallium Radioisotopes; Tissue Distribution

The quantitative gated SPECT (QGS) software that has automatic edge detection algorithm of the left ventricle, is able to calculate LV volumes and visualize LV wall motion with perfusion throughout the cardiac cycle. We evaluated the reliability of global and regional LV function derived from QGS using 99mTc-tetrofosmin by comparing with left ventricular cineangiography (LVG) and echocardiography (ECHO). In 22 cardiac patients, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were calculated. Using cinematic display, regional LV wall motion were scored on a 3-point scale (1 = normal, 2 = hypokinesis, 3 = akinesis; WMS). EDV, ESV and LVEF correlated well with those by LVG (p < 0.001 for each). Correlation between WMS derived from QGS and ECHO was high (r = 0.85, p < 0.001). There was an inverse correlation between WMS and LVEF (r = 0.77, p < 0.001). In conclusion, QGS is useful to evaluate global LV function. Regional wall motion evaluated by QGS is good enough for clinical application.

Topics: Cineangiography; Echocardiography; Electrocardiography; Female; Gated Blood-Pool Imaging; Heart Diseases; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Ventricular Function, Left

The introduction of new cardiac SPECT cameras has made it practical to do dynamic SPECT imaging and opened the door to performing myocardial blood flow (MBF) imaging with SPECT. In this paper, we describe in detail our approach to dynamic SPECT MBF imaging using a multi-pinhole cardiac SPECT camera and commercially available kinetic analysis software. We use a 1-day rest/stress protocol with 370 MBq injected at rest and 1,000 MBq at stress with a 1- to 2-hour interval between rest and stress imaging. The tracer is injected mechanically over 30 seconds using a syringe pump. Projection data are acquired in listmode for a duration of 11 minutes and then reframed into a dynamic series. Each image is reconstructed independently using vendor-supplied software. The dynamic images are corrected for residual activity and manually corrected for motion using rigid-body translation. The uptake rate constant, K1, is calculated using a 1-tissue-compartment kinetic model and converted to MBF using a previously determined extraction fraction correction.

Topics: Coronary Circulation; Gamma Cameras; Heart Diseases; Humans; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals

Topics: Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; Female; Heart Diseases; Humans; Incidental Findings; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Thymoma; Thymus Neoplasms

The applicability of ultra-low-dose computed tomography (CT) for attenuation correction (AC) of single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) remains elusive.. One-hundred patients underwent one-day. Attenuation maps for MPI obtained from ultra-low radiation dose CT scans are interchangeable with attenuation maps from standard-dose CT while offering a substantial reduction in radiation dose exposure.

Topics: Aged; Cadmium; Female; Heart Diseases; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Prospective Studies; Radiation Dosage; Reproducibility of Results; Sensitivity and Specificity; Tellurium; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Zinc

Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) is useful in the evaluation of cardiac allograft vasculopathy (CAV) in heart transplant (HTx) recipients. The current study evaluated the long-term prognostic value of stress SPECT MPI for predicting all-cause mortality and cardiac events in HTx recipients.. The study population consisted of 166 HTx recipients (mean age 54 ± 10 years, 84% male) who underwent exercise or dobutamine stress. MPI abnormalities were detected in 55 patients (33%), including fixed defects in 28 patients (17%), partially reversible in 17 patients (10%), and completely reversible defects in 10 patients (6%). During a median follow-up of 12.8 years (range 0-15, mean follow-up 9.5 years), 109 (66%) patients died (all-cause mortality), of which 67 (40%) were due to cardiac causes. A total of 5 (3%) patients experienced a non-fatal MI. HTx recipients with a normal stress. Stress

Topics: Adult; Exercise Test; Female; Heart Diseases; Heart Transplantation; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Radiopharmaceuticals; Time Factors; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

This study sought to examine current laboratory practices for radiation effective doses for myocardial perfusion imaging (MPI) and laboratory adherence to guideline-directed radiation reduction practices.. A recent focus on radiation dose reduction for cardiovascular imaging has led to several published guidelines and consensus statements detailing performance metrics for laboratory practices. We sought to examine laboratory adherence to optimized radiation dose protocol recommendations among 5,216 submitted cases from 1,074 MPI laboratories evaluated for Intersocietal Accreditation Commission accreditation.. Eligible imaging centers included MPI laboratories enrolled in the Intersocietal Accreditation Commission data repository of accreditation applications from 2012 to 2013. Accreditation requires submission of 3 to 5 cases for evaluation of a range of representative cases. Based on standard dosimetry for rest and stress MPI, an effective dose (in millisieverts) was calculated. Model simulations were performed to estimate guideline-directed effective doses.. The average effective dose was 14.9 ± 5.8 mSv (range 1.4 to 42.4 mSv). A 1-day technetium Tc 99m protocol was used in 82.9% of cases, whereas a 2-day technetium Tc 99m and dual isotope protocol was used in 7.5% of submitted cases. Only 1.5% of participating imaging centers met current guidelines for an average laboratory radiation exposure ≤9 mSv, whereas 10.1% of patient effective doses were >20.0 mSv. A model simulation replacing the radiation exposure of dual isotope MPI with that of a 1-day technetium Tc 99m protocol reduced the proportion of patients receiving an effective dose >20 mSv to only 2.7% of cases (p < 0.0001).. Mandatory laboratory accreditation for MPI allows for examination of current radiation dosimetry practices. Current guidelines for reduced patient-specific radiation exposure are rarely implemented, with few laboratories meeting recommendations of ≤9 mSv for 50% of patients. Increased educational efforts and the development of performance measures for laboratory accreditation may be required to meet current radiation dose-reduction standards.

Topics: Accreditation; Clinical Laboratory Techniques; Computer Simulation; Coronary Circulation; Databases, Factual; Guideline Adherence; Heart Diseases; Humans; Laboratory Proficiency Testing; Myocardial Perfusion Imaging; Observer Variation; Organophosphorus Compounds; Organotechnetium Compounds; Practice Guidelines as Topic; Predictive Value of Tests; Radiation Dosage; Radiation Exposure; Radiopharmaceuticals; Reproducibility of Results; Technetium Tc 99m Sestamibi; United States

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.

Topics: Adenosine A2 Receptor Antagonists; Aged; Asthma; Atrioventricular Block; Bronchoconstriction; Chi-Square Distribution; Female; Heart Diseases; Hemodynamics; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Pulmonary Disease, Chronic Obstructive; Purines; Pyrazoles; Radiopharmaceuticals; Retrospective Studies; Risk Assessment; Risk Factors; Tachycardia, Supraventricular; Tomography, Emission-Computed, Single-Photon; Vasodilator Agents

The aim of this study was to determine the impact of attenuation correction with CT (CT-AC) on the prognostic value of SPECT myocardial perfusion imaging (SPECT MPI).. The summed stress score (SSS; 20-segment model) was obtained from filtered backprojection (FBP) and iterative reconstruction with CT-AC in 876 consecutive patients undergoing a 1-d stress-rest (99m)Tc-tetrofosmin SPECT MPI study for the evaluation of known or suspected coronary artery disease. Survival free of major adverse cardiac events (MACEs; cardiac death or nonfatal myocardial infarction) and survival free of any adverse cardiac events (including cardiac hospitalization, unstable angina, and late coronary revascularization) were analyzed by Kaplan-Meier analysis.. At a mean follow-up of 2.3 ± 0.6 y, a total of 184 adverse events occurred in 145 patients, including 35 MACEs (16 cardiac deaths [rate, 1.8%] and 19 nonfatal myocardial infarctions [rate, 2.2%]). With FBP, an SSS of 0-3 best distinguished patients with a low MACE rate (0.6%), followed by an SSS of 4-8 (4.3%), with increased MACE rate, and an SSS of 9-13 (3.8%), which was comparable. By contrast, with CT-AC the discrimination of low from intermediate MACE rate was best observed between an SSS of 0 (0%) and an SSS of 1-3 (3.7%), with a plateau at an SSS of 4-8 (3.2%).. CT-AC for SPECT MPI allows improved risk stratification. The prognostically relevant SSS cutoff is shifted toward lower values.

Topics: Adenosine; Aged; Death, Sudden, Cardiac; Disease-Free Survival; Electrocardiography; Endpoint Determination; Female; Follow-Up Studies; Heart; Heart Diseases; Humans; Image Interpretation, Computer-Assisted; Kaplan-Meier Estimate; Male; Middle Aged; Myocardial Infarction; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Prognosis; Radiopharmaceuticals; Risk Factors; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

To evaluate the prognostic value of exercise myocardial scintigraphy in patients undergoing incomplete revascularization by means of percutaneous coronary intervention (PCI) with at least a residual chronic total occlusion (CTO) left untreated.. Of 569 consecutive patients with multivessel disease undergoing myocardial scintigraphy after incomplete revascularization by PCI between March 1997 and December 2004, 126 (79% male, 64+/-10 years) with >or= 1 residual CTO fulfilled the eligibility criteria and entered in the study. Hard events defined as cardiac death and myocardial infarction, soft events defined as incidence of unstable angina and PCI procedures, and their composite were assessed at a median follow-up period of 44 months.. Hard events were observed in six patients (4.8%). All of them had severely abnormal perfusion defects detected by myocardial scintigraphy. Soft events occurred in 0 (0%), 10 (7.9%), and 15 (11.9%) patients with normal, mildly abnormal, and severely abnormal perfusion, respectively. In the Kaplan-Meier analysis, the log-rank test was statistically significant across patients stratified by summed stress score either in terms of hard, soft and hard, or soft events. Univariate and multivariate Cox proportional-hazards showed an incremental significant information when the scintigraphic variables were added to clinical, angiographic, left ventricular ejection fraction, and Duke treadmill score, for prediction of the composite of hard and soft cardiac events (P < 0.006).. Among patients with a residual CTO left untreated after PCI, myocardial perfusion imaging provides significant independent information concerning the subsequent risk of cardiac events.

Topics: Aged; Angioplasty, Balloon, Coronary; Chronic Disease; Coronary Angiography; Coronary Circulation; Coronary Occlusion; Exercise Test; Female; Follow-Up Studies; Heart Diseases; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Prognosis; Proportional Hazards Models; Radiopharmaceuticals; Risk Assessment; Tomography, Emission-Computed, Single-Photon

Our purpose was to describe a novel, rapid stress thallium-201 (Tl-201)/rest technetium-99m (Tc-99m) agent myocardial perfusion imaging (MPI) protocol (Tl/Tc) with a high-speed MPI scanner and to compare this protocol with a standard rest/stress Tc-99m agent protocol (Tc/Tc) with respect to image quality and radiation dosimetry.. Recent advances in gamma camera technology have provided opportunity for improved SPECT MPI protocols. A rapid Tl/Tc protocol that could improve image information while maintaining a low radiation burden for the patient would be desirable.. We compared high-speed SPECT MPI studies in 374 consecutive patients undergoing exercise or pharmacologic Tl/Tc protocol to those of 262 patients undergoing rest/stress Tc/Tc protocol.. Tl/Tc imaging was accomplished in <20 min. Overall image quality was good to excellent in 96% and 98% of patients with the Tl/Tc and the Tc/Tc protocols, respectively (p = ns). Beginning rest imaging within 2 min after rest injection with the Tl/Tc protocol did not result in reduced confidence in image interpretation. Early rest Tc images of the Tl/Tc protocol showed less extracardiac activity than was observed on standard rest imaging used in the Tc/Tc protocol (84% vs. 61%), respectively (p < 0.01). The normalcy rate was high in both groups (100% vs. 92%). Radiation burden was similar between the Tl/Tc and Tc/Tc protocols.. A rapid stress Tl-201/rest Tc-99m protocol for use with high-speed SPECT MPI has image quality and radiation dosimetry similar to those observed with a conventional rest/stress Tc-99m protocol. The Tl/Tc protocol offers promise as an efficient and relatively low radiation dose method, in which the superior qualities of Tl-201 for stress imaging and of the Tc-99m agents for rest imaging can be preserved. The findings also suggest that with rapid imaging rest MPI immediately after Tc-99m agent injection may be superior to standard delayed image initiation.

Topics: Adenosine; Aged; Exercise Test; Female; Heart Diseases; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Radiation Dosage; Radiopharmaceuticals; Technetium Tc 99m Sestamibi; Thallium Radioisotopes; Time Factors; Tomography, Emission-Computed, Single-Photon

Topics: Adenosine; Exercise Test; Heart Diseases; Humans; Image Interpretation, Computer-Assisted; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Predictive Value of Tests; Radiation Dosage; Radiopharmaceuticals; Technetium Tc 99m Sestamibi; Thallium Radioisotopes; Time Factors; Tomography, Emission-Computed, Single-Photon

Topics: Coronary Artery Disease; Coronary Occlusion; Diabetes Complications; Fistula; Heart Diseases; Heart Ventricles; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Emergency department (ED) patients with chest pain (CP) and a nondiagnostic electrocardiogram (ECG) present difficult management decisions. The purpose of this study was to investigate the utility of resting radionuclide SPECT myocardial perfusion imaging (SPECT MPI)-including an overnight delayed image acquisition protocol-in identifying patients presenting to the ED with CP at risk for cardiac events.. Patients presenting to the ED with CP and a nondiagnostic ECG were prospectively enrolled and underwent chest pain center evaluation. All patients also underwent resting gated SPECT MPI using (99m)Tc-tetrofosmin tracer. Patients presenting on weeknights between 12 am and 6 am had tracer injection in the ED with image acquisition delayed until later in the morning. Patients were monitored for a 30-d occurrence of cardiac events.. Over a 16-mo period, 479 patients were enrolled and completed follow-up. For the prediction of 30-d cardiac events, resting SPECT MPI demonstrated a sensitivity and a specificity of 76.9% and 92.4%, respectively. Positive and negative predictive values were 22.2% and 99.3%, respectively. Among the 3 patients with a normal perfusion scan who suffered cardiac events, all had tracer injection several hours after resolution of CP. The overnight delayed image acquisition protocol provided a negative predictive value of 100% for the 44 patients whose image acquisition was delayed until the following morning.. A normal resting SPECT MPI in ED patients presenting with CP predicts a very low occurrence of 30-d cardiac events. A delayed image acquisition protocol did not decrease the accuracy of SPECT MPI. Such a protocol may be useful in increasing the availability of this imaging modality.

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Chest Pain; Electrocardiography; Female; Gated Blood-Pool Imaging; Heart Diseases; Humans; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Pain Clinics; Perfusion; Radioisotopes; Radiopharmaceuticals; Rest; Risk Assessment; Risk Factors; Sensitivity and Specificity; Time; Tomography, Emission-Computed, Single-Photon

The purpose of this study was to assess the influence of patient gender and choice of perfusion tracer on computer-based interpretation of myocardial perfusion images. For the image interpretation, an automated method was used based on image processing and artificial neural network techniques. A total of 1000 patients were studied, all referred to the Royal Brompton Hospital in London for myocardial perfusion scintigraphy over a period of 1 year. The patients were randomized to receive either thallium or one of the two technetium tracers, methoxyisobutylisonitrile or tetrofosmin. Artificial neural networks were trained with either mixed gender or gender-specific and mixed tracer or tracer-specific training sets of different sizes. The performance of the networks was assessed in separate test sets, with the interpretation of experienced physicians regarding the presence or absence of fixed or reversible defects in the images as the gold standard. The neural networks trained with large mixed gender training sets were as good as the networks trained with gender-specific data sets. In addition, the neural networks trained with large mixed tracer training sets were as good as or better than the networks trained with tracer-specific data sets. Our results indicate that the influence of patient gender and perfusion tracer are of minor importance for the computer-based interpretation of the myocardial perfusion images. The differences that occur can be compensated for by larger training sets.

Topics: Adult; Aged; Aged, 80 and over; Female; Heart Diseases; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Neural Networks, Computer; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; ROC Curve; Sex Factors; Technetium Tc 99m Sestamibi; Thallium Radioisotopes

Topics: Aged; Bone and Bones; Heart; Heart Diseases; Humans; Incidental Findings; Male; Multiple Myeloma; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Whole-Body Counting

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

Topics: Adult; Female; Heart Diseases; Humans; Lupus Erythematosus, Systemic; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

To establish a noninvasive diagnostic method for early assessment of cardiac involvement in Kawasaki disease (KD), 28 children with KD were included in this study. Two-dimensional echocardiography (2D-Echo) to detect the aneurysms of coronary arteries (CA), as well as rest and dipyridamole-stress technetium-99m tetrofosmin (Tc-TF) myocardial perfusion single photon emission computed tomography (SPECT) to detect abnormal myocardial perfusion were performed in all of the 28 children with KD and to compare each other. The results showed that (1). 42.9% of cases had no aneurysm and 57.1% had significant aneurysms detected by 2D-Echo; (2). 42.9% of cases had normal perfusion and 57.1% of cases had abnormal myocardial perfusion assessed by Tc-TF myocardial perfusion SPECT; (3). 25.0% of cases showed both normal 2D-Echo and Tc-TF myocardial perfusion SPECT findings and 39.3% of cases showed both abnormal 2D-Echo and Tc-TF myocardial perfusion SPECT findings; and (4). there was poor agreement between 2D-Echo and Tc-TF myocardial perfusion SPECT findings (P>0.05). We concluded that poor agreement exists between aneurysms and abnormal myocardial perfusion detected by 2D-Echo and Tc-TF myocardial perfusion SPECT findings in patients with KD.

Topics: Adolescent; Child; Child, Preschool; Coronary Circulation; Dipyridamole; Echocardiography; Female; Heart Diseases; Humans; Infant; Male; Mucocutaneous Lymph Node Syndrome; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Vasodilator Agents

Brown adipose tissue (BAT) is a site of nonshivering thermogenesis in mammals. The mitochondria of BAT operate in an uncoupled mode and increase fatty acid oxidation to produce heat at birth. Thus, the BAT of human infants and children contains more active mitochondria than that of adults. We surmised that because (99m)Tc-tetrofosmin can be absorbed by functional mitochondria in the myocardium and in tumor cells, it could reveal mitochondrial function in BAT.. Between January 1999 and December 2002, we retrospectively analyzed 385 consecutive studies of (99m)Tc-tetrofosmin uptake in pediatric patients with cardiac disorders. All patients with symmetric (99m)Tc-tetrofosmin accumulation within the neck and shoulder region according to planar images were selected, and the features of the uptake were analyzed.. Increased symmetric (99m)Tc-tetrofosmin uptake in the interscapular BAT was a typical profile of 65 of the 385 patients (17%). The frequency of (99m)Tc-tetrofosmin uptake was significantly higher in winter than in spring or summer (P < 0.05) and prominent in newborns. The frequency peaked between 0 and 2 y of age and then declined with age.. Gamma-camera imaging with (99m)Tc-tetrofosmin can reveal interscapular BAT distribution in infants and children in terms of mitochondrial activity.

Topics: Adipose Tissue, Brown; Adolescent; Adult; Child; Child, Preschool; Female; Heart Diseases; Humans; Infant; Infant, Newborn; Male; Neck; Observer Variation; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Retrospective Studies; Scapula; Shoulder; Tissue Distribution

We have developed new software which can evaluate left ventricular (LV) diastolic functional parameters from a quantitative gated SPET (QGS) program. To examine its accuracy, we compared these findings with the LV diastolic functional indices obtained from gated radionuclide ventriculography (RNV). Twenty-four patients were selected for this study. Gated SPET with technetium-99m tetrofosmin was performed and the QGS program was used with a temporal resolution of 32 frames per R-R interval. The LV volume of each frame was calculated and four harmonics of Fourier series were retained for the analysis of the LV volume curve. From this fitted curve and its first derivative curve, we derived LV systolic functional indices, e.g. ejection fraction (EF), peak ejection rate (PER) and time to PER (TPER), as well as LV diastolic functional variables, e.g. 1/3 filling fraction (1/3 FF), peak filling rate (PFR) and time to PFR (TPFR). Within 5+/-2 days, gated RNV was performed and diastolic functional parameters were determined by the same method. No significant difference was observed between the variables calculated by gated SPET and by gated RNV. There was a good correlation between EF, PER, TPER, 1/3 FF, PFR and TPFR determined by these two methods (EF: r=0.95, P<0.0001; PER: r=0.87, P<0.0001; TPER: r=0.84, P<0.0001; 1/3 FF: r=0.87, P<0.0001; PFR: r=0.92, P<0.0001; TPFR: r=0.89, P<0.0001). Bland-Altman plots did not reveal any significant degree of directional measurement bias in any of the comparisons of gated SPET data and RNV data. It is concluded that, in addition to the conventional LV systolic functional indices, our program accurately provides LV diastolic functional parameters from gated SPET. Also, this program will be useful for detecting LV diastolic dysfunction in various cardiac diseases before LV systolic dysfunction becomes evident.

Topics: Diastole; Electrocardiography; Female; Gated Blood-Pool Imaging; Heart Diseases; Humans; Male; Middle Aged; Observer Variation; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Reproducibility of Results; Software; Stroke Volume; Tomography, Emission-Computed, Single-Photon; Ventricular Function, Left

Topics: Adult; Cold Temperature; CREST Syndrome; Female; Heart; Heart Diseases; Humans; Myocardial Ischemia; Organophosphorus Compounds; Organotechnetium Compounds; Tomography, Emission-Computed, Single-Photon