Donna Natale

Comparison and reproducibility of visual echocardiographic and quantitative radionyclide left ventricular ejection fractions

Left ventricular (LV) ejection fraction (EF) is commonly assessed by equilibrium radionuclide angiography and echocardiography. These methods are presumed to be interchangeable for this purpose. This study (1) compares quantification of LVEF by equilibrium radionuclide angiography with visual estimation of LVEF by echocardiography, (2) determines the reproducibility of both methods, and (3) evaluates whether differences in determinations of LVEF are of clinical relevance. Seventy-three clinically stable patients had both equilibrium radionuclide angiography and echocardiography performed within a 4-day period. LVEF by both techniques was compared after blinded analysis by 3 echocardiographers and 3 nuclear technologists. Reproducibility was assessed by blinded repeat analysis after a 1-week interval. The frequency of differences in repeat assessments of EF that the authors considered to be of potential clinical relevance (i.e., difference > or = 10% EF units) was assessed for both techniques. Correlation of LVEF determined by both methods was good (r = 0.81, SEE = 3.5) but with substantial differences in individual patients (limits of agreement, 23.6%). Intra- and inter-observer reproducibility was good for both methods, but better for radionuclide LVEF than for echocardiographic LVEF. Limits of agreement were substantially better for radionuclide LVEF than for echocardiographic LVEF (1.8% to 3.6% versus 13.4% to 17.4%, respectively). Clinically relevant differences did not occur on repeat processing of equilibrium radionuclide angiography. In contrast, potentially clinically relevant differences occurred in 8% to 26% of studies on repeat analysis of echocardiography. Thus, LVEF determined by equilibrium radionuclide angiography and echocardiography show good agreement. Both methods provide clinically valuable measurements for LV function. However, when a precisely reproducible measurement is required for patient management decisions, equilibrium radionuclide angiography is the method of choice.

An economic analysis of an aggressive diagnostic strategy with single photon emission computed tomography myocardial perfusion imaging and early exercise stress testing in emergency department patients who present with chest pain but nondiagnostic electrocardiograms: Results from a randomized trial

STUDY OBJECTIVE Conventional emergency department testing strategies for patients with chest pain often do not provide unequivocal diagnosis of acute coronary syndromes. This study was conducted to determine whether the routine use of single photon emission computed tomography (SPECT) imaging at rest and early exercise stress testing to assess intermediate-risk patients with chest pain and no ECG evidence of acute ischemia will lead to earlier discharges, more discriminate use of coronary angiography, and an overall reduction in average costs of care with no adverse clinical outcomes. METHODS All patients in this study had technetium 99m tetrofosmin SPECT imaging at rest and were randomly assigned to either a conventional (results of the imaging test blinded to the physician) or perfusion imaging-guided (results of the imaging test unblinded to the physician) strategy. Patients in the conventional arm were treated at their physicians discretion. Patients in the perfusion imaging-guided arm were treated according to a predefined protocol based on SPECT imaging test results: coronary angiography after a positive scan result and exercise treadmill testing after a negative scan result. Study endpoints consisted of total in-hospital costs and length of stay. Hospital costs were calculated using hospital department-specific Medicare cost/charge ratios. Length of stay was calculated as total hospital room days billed (regular and intensive care). RESULTS We enrolled 46 patients, 9 with acute myocardial infarctions. Patients randomly assigned to the perfusion imaging-guided arm had

Quantitative comparison of single-isotope and dual-isotope stress-rest single-photon emission computed tomographic imaging for reversibility of defects

1,843 (95% confidence interval [CI]

The Yale-CQ method for cardiac SPECT quantification: phantom validation and patient application

431 to

Quantitative Comparison of Planar and SPECT Normal Data Files of Thallium-201, Technetium-99m-Sestamibi, Technetium-99m-Tetrofosmin and Technetium-99m-Furifosmin

6,171) lower median in-hospital costs and 2.0-day (95% CI 1.0 to 3.0 days) shorter median lengths of stay but similar rates of in-hospital and 30-day follow up events as patients in the conventional arm. CONCLUSION An ED chest pain diagnostic strategy incorporating acute resting 99mTc tetrofosmin SPECT imaging and early exercise stress testing may lead to reduced in-hospital costs and decreased length of stay for patients with acute chest pain and nondiagnostic ECGs. [Stowers SA, Eisenstein EL, Wackers FJTh, Berman DS, Blackshear JL, Jones AD Jr, Szymanski TJ Jr, Lam LC, Simons TA, Natale D, Paige KA, Wagner GS. An economic analysis of an aggressive diagnostic strategy with single photon emission computed tomography myocardial perfusion imaging and early exercise stress testing in emergency department patients who present with chest pain but nondiagnostic electrocardiograms: results from a randomized trial. Ann Emerg Med. January 2000;35:17-25.].STUDY OBJECTIVE Conventional emergency department testing strategies for patients with chest pain often do not provide unequivocal diagnosis of acute coronary syndromes. This study was conducted to determine whether the routine use of single photon emission computed tomography (SPECT) imaging at rest and early exercise stress testing to assess intermediate-risk patients with chest pain and no ECG evidence of acute ischemia will lead to earlier discharges, more discriminate use of coronary angiography, and an overall reduction in average costs of care with no adverse clinical outcomes. METHODS All patients in this study had technetium 99m tetrofosmin SPECT imaging at rest and were randomly assigned to either a conventional (results of the imaging test blinded to the physician) or perfusion imaging-guided (results of the imaging test unblinded to the physician) strategy. Patients in the conventional arm were treated at their physicians discretion. Patients in the perfusion imaging-guided arm were treated according to a predefined protocol based on SPECT imaging test results: coronary angiography after a positive scan result and exercise treadmill testing after a negative scan result. Study endpoints consisted of total in-hospital costs and length of stay. Hospital costs were calculated using hospital department-specific Medicare cost/charge ratios. Length of stay was calculated as total hospital room days billed (regular and intensive care). RESULTS We enrolled 46 patients, 9 with acute myocardial infarctions. Patients randomly assigned to the perfusion imaging-guided arm had

Quantification of normal pattern of regional myocardial uptake of 18F LMI1195, a novel tracer for imaging myocardial sympathetic function: First-in-human study

1,843 (95% confidence interval [CI]

Guidelines for technologist training in nuclear cardiology

431 to

Hybrid SPECT/CT attenuation correction improves specificity and normalcy rate: A multicenter trial

6,171) lower median in-hospital costs and 2.0-day (95% CI 1.0 to 3.0 days) shorter median lengths of stay but similar rates of in-hospital and 30-day follow up events as patients in the conventional arm. CONCLUSION An ED chest pain diagnostic strategy incorporating acute resting (99m)Tc tetrofosmin SPECT imaging and early exercise stress testing may lead to reduced in-hospital costs and decreased length of stay for patients with acute chest pain and nondiagnostic ECGs.

The influence of clopidogrel on ischemia diagnosed by myocardial perfusion stress testing

BackgroundDual-isotope rest/stress single-photon emission computed tomographic (SPECT) imaging is a time-saving imaging protocol. However, the stress radiotracer, technetium 99m-labeled sestamibi, and the rest radiotracer, thallium 201, have different physical properties and myocardial kinetics. In patients with abnormal resting myocardial perfusion, these differences may affect quantification of rest defect size and defect reversibility. The purpose of the study was to compare myocardial perfusion defect reversibility quantitatively by single-isotope (rest/stress sestamibi) and dual-isotope (rest thallium/stress sestamibi) SPECT.Methods and ResultsThirty patients with prior myocardial infarction underwent rest/stress sestamibi SPECT imaging and rest thallium SPECT imaging. Defects were quantified according to circumferential count profiles with a normal sestamibi database. The images of a subgroup of 21 patients were processed with radiotracer-specific normal databases. Defect size and defect reversibility were compared quantitatively for single-isotope and dual-isotope SPECT. Rest sestamibi defect size was significantly larger than rest thallium defect size (19±15 vs 14±16; p=0.007). Defect reversibility was larger with thallium than with sestamibi (10±9 vs 6±6; p=0.002). With radiotracer-specific normal databases, mean rest sestamibi and thallium defect sizes in 21 patients were not different (23±19 vs 21±17; difference not significant). With radiotracer-specific normal databases, mean defect reversibility was not different with either sestamibi or thallium (6±6 vs 8±9; difference not significant), although correlation among individual patients was only fair (r2=0.48).ConclusionIn patients with prior myocardial infarction, stress-induced defect reversibility is quantitatively larger with dual-isotope imaging than with single-isotope imaging. Quantitative processing of dual-isotope images requires radiotracer-specific normal databases. Because of different characteristics of sestamibi and thallium, assessment of defect reversibility on dual-isotope images should be made with caution. Only relatively large defect reversibility can be assumed to represent true stress-induced myocardial ischemia.

913-116 Quantitative Comparison of Planar and SPECT Normal Databases of Thallium-201, Sestamibi, Tetrofosmin and Furifosmin

Performance of the Yale-CQ SPECT quantification method was evaluated using phantom and patient data. Forty-two phantom experiments and 218 patient studies were included in this evaluation. The quantification was carried out by the automatic and manual methods. For the phantom data, the success rate (SR) of the automatic method was 100%. The mean absolute errors of estimating the center location (MAE-x, MAE-y and radii MAE-r) of the short axial slices were 0.28, 0.57 and O.11 pixels, respectively, as for comparison of the automatic and manual methods. Correlation between the actual defect size and the average defect score was excellent (r=0.96). The consistency of the results from the automatic and manual methods was high (r=0.98). Inter-observer results obtained by the manual method were highly reproducible (r=0.99). For patient data, SR was 76%, and MAE-x, MAE-y and MAE-r were 0.72, 1.08 and 1.03 pixels, respectively. Results by the automatic and manual methods were highly consistent (r=0.99). This validation showed the Yale-CQ method may provide a reliable measurement of myocardial perfusion abnormality which can be expressed as a percent of LV.