Interhospital observer agreement in interpretation of exercise myocardial Tc-99m tetrofosmin SPECT studies

Normal myocardial perfusion SPECT database for the Spanish population

INTRODUCTION AND OBJECTIVES

The aims of this study were to create a Spanish database of normal myocardial perfusion SPECT (single-photon emission computed tomography) data, termed the normal Spanish database, and to compare it with a database of normal data from the North American population.

METHODS

We selected 104 healthy volunteers (45 female, mean age 42+/-14 years) who underwent SPECT during stress and at rest. The findings were analyzed using the 4DM-SPECT commercial software package. The resulting normal Spanish database for males and females was compared with the North American population database (from 70 men and 60 women) provided with the 4DM-SPECT software.

RESULTS

In the Spanish database, the highest percentage uptake during both stress and rest was observed in medial-lateral region and the lowest, in the basal-septal region. The percentage uptake in the anterior-medial region was significantly lower in women than men, while uptake in the inferior, medial-septal and apical regions was lower in men than women. Data values in the Spanish database were significantly lower for the majority of heart regions than those in the database with the 4DM-SPECT software.

CONCLUSIONS

A Spanish database of normal myocardial perfusion SPECT data was created and included separate data for men and women. Significant differences were observed between this database and a commercial North American database that is commonly used in semiquantitative studies.

Comparison of diagnostic performances of three different software packages in detecting coronary artery disease

PURPOSE

Quantification of myocardial perfusion scintigraphy is frequently performed to assist physicians in detecting coronary artery disease (CAD). Software packages provide automated quantification of perfusion data. We aimed to compare the three commonly used software packages, Emory Cardiac Toolbox (ECT v2 and ECT v3), 4D-MSPECT (4DM v2 and 4DM v4) and Quantitative Perfusion SPECT (QPS v3 and QPS v4).

METHODS

We selected 283 patients who had a myocardial perfusion scintigraphy with (201)Tl followed by coronary angiography within 3 months. Summed stress score (SSS), summed difference score (SDS), total stress defect extent (TDE) and regional stress defect extent values were obtained from programs. A ≥70% stenosis in coronary arteries and their major branches was considered positive for CAD. A subgroup of patients was used to form an institutional normal database for QPS and 4DM. Receiver-operating characteristic (ROC) analysis to detect CAD was performed.

RESULTS

Mean SSS ± SD (vendor) for ECT v3, QPS v4 and 4DM v4 were 9.2 ± 7.1, 10.1 ± 6.8 and 5.5 ± 6.1, respectively. Area under the curve (AUC) values of SSS ROC analysis were 0.738 ± 0.031 for QPS v3, 0.755 ± 0.030 for QPS v4, 0.758 ± 0.030 for ECT v2, 0.778 ± 0.029 for ECT v3 and 0.771 ± 0.030 for 4DM v4. The AUC values for TDE were 0.755 ± 0.030 for QPS v4, 0.769 ± 0.030 for ECT v3 and 0.775 ± 0.029 for 4DM v4. The differences were not significant for both SSS and TDE. Differences of AUC between regional stress defect extent values of programs and AUC of SSS between institutional and vendor normal databases were not significant.

CONCLUSION

The diagnostic performances of programs to detect CAD are similar. However, there are differences in the magnitudes of the quantitative values produced by the programs.

Diagnostic impact of SPECT image display on assessment of obstructive coronary artery disease

BACKGROUND

Diagnostic assessment of myocardial perfusion impacts the management of patients with suspected coronary artery disease (CAD). Although various image displays are available for single photon emission computed tomography (SPECT) interpretation, the effects of display differences on SPECT interpretation remain undetermined.

METHODS AND RESULTS

We studied 183 patients undergoing SPECT, including 131 consecutive patients referred for angiography and 52 at low CAD risk. Studies were visually interpreted by use of color and gray images, with readers blinded to the results of the other display. In accordance with established criteria, a summed stress score (SSS) of 4 or greater was considered abnormal. The prevalence of abnormal SPECT findings was higher with gray images than with color images (54% vs 48%, P < .001) based on a uniform criterion (SSS > or =4). However, color images yielded equivalent sensitivity (79% vs 82%, P = .7) and improved specificity for global (50% vs 33%, P = .02) and vessel-specific CAD involving the right coronary artery (P < .01) and left anterior descending artery (P < .05). When the criterion for gray images was adjusted upward (SSS > or =5) to reflect increased mean defect severity (SSS of 5.1 vs 4.4, P = .01), gray and color images provided equivalent sensitivity and specificity for global and vessel-specific CAD.

CONCLUSIONS

SPECT interpretation can vary according to image display as a result of differences in perfusion defect severity. Adjustment of abnormality criteria for gray images to reflect minor increases in defect severity provides equivalent diagnostic performance of gray and color displays for CAD assessment.

EANM/ESC procedural guidelines for myocardial perfusion imaging in nuclear cardiology

The European procedural guidelines for radionuclide imaging of myocardial perfusion and viability are presented in 13 sections covering patient information, radiopharmaceuticals, injected activities and dosimetry, stress tests, imaging protocols and acquisition, quality control and reconstruction methods, gated studies and attenuation-scatter compensation, data analysis, reports and image display, and positron emission tomography. If the specific recommendations given could not be based on evidence from original, scientific studies, we tried to express this state-of-art. The guidelines are designed to assist in the practice of performing, interpreting and reporting myocardial perfusion SPET. The guidelines do not discuss clinical indications, benefits or drawbacks of radionuclide myocardial imaging compared to non-nuclear techniques, nor do they cover cost benefit or cost effectiveness.

Observer variability in the evaluation of dual-isotope Tl-201/Tc-99m sestamibi rest/stress myocardial perfusion SPECT in men and women with known or suspected stable angina pectoris

BACKGROUND

Observer variability of dual-isotope myocardial perfusion imaging (MPI) with single photon emission computed tomography has rarely been investigated. The aim of our study was to evaluate the interpretive reproducibility with this technique.

METHODS AND RESULTS

We report on 507 patients with known or suspected stable angina who were studied before coronary angiography. A 1-day thallium 201/technetium 99m sestamibi rest/stress MPI protocol was used. MPI was interpreted by 2 independent observers without knowledge of clinical data, using a 20-segment scoring model. By consensus, the overall rate of abnormal MPI was 49% (59% in men and 34% in women). The interobserver agreement for the whole group (kappa = 0.85) and for men and women separately (kappa = 0.86 and 0.82, respectively) was excellent with regard to the overall diagnosis (normal, reversible, or fixed defects) as well as left anterior descending and left circumflex artery vascular territories (kappa = 0.85 and 0.82, respectively). However, in the right coronary artery territory, agreement was excellent in men (kappa = 0.83) but moderate in women (kappa = 0.57).

CONCLUSIONS

In a relatively large group of men and women with stable angina pectoris, interpretive reproducibility (overall and individual vessel diagnosis) was excellent, except in the right coronary artery territory of women, in which it was moderate.

Metabolic Syndrome and Ischemic Heart Disease in Gout

BACKGROUND

For decades, gout has been associated with several metabolic abnormalities and with ischemic heart disease (IHD).

OBJECTIVE

Our aim was to determine the prevalence of metabolic syndrome by Adult Treatment Panel III criteria (ATP III) and ischemic heart disease (IHD) by electrocardiogram (EKG) and/or single photon emission computed tomography (SPECT) in patients with gout.

METHODS

We included 64 consecutive outpatients with primary gout, but no history of IHD, attending our clinic for the first time. Demographic and clinical data were recorded and resting electrocardiogram, lipid profile, fasting insulin, and SPECT with Tc sestamibi were performed. Metabolic syndrome was defined according to ATP III criteria (> or =3 of the following data: 1) hyperglycemia (fasting glucose > or =110 mg/dL) or previous diagnosis of diabetes mellitus, 2) hypertension (> or =130/85 mm Hg) or previous diagnosis, 3) high-density lipoprotein (HDL) <40 mg/dL (men) or <50 mg/dL (women), 4) triglycerides > or =150 mg/dL, and 5) obesity.

RESULTS

IHD was diagnosed in 10 patients (16%); 2 had EKG changes compatible with previous silent myocardial necrosis and the other 8 had abnormal SPECT. The prevalence of metabolic syndrome was 82%, all patients had at least 1 metabolic abnormality, but all the patients with IHD had metabolic syndrome (3 criteria according with ATP III). Patients with IHD differed from those without IHD in the percentage of HDL levels <40 mg/dL (100% vs. 82%; P = 0.05) as well as glucose and insulin levels in the fasting state (129.3 +/- 6.1 mg/dL vs. 92.7 +/- 16.7 mg/dL; P = 0.000; and 21.1 +/- 6.0 vs. 17.5 +/- 8.6 UI/mL; P = 0.03) and low-density lipoproteins (143.9 +/- 21.3 mg/dL vs. 118.2 +/- 47.7 mg/dL; P = 0.014). In contrast, serum creatinine and urea (1.02 +/- 0.13 mg/dL vs. 1.5 +/- 1.5 mg/dL; P = 0.024; and 33.9 +/- 9.3 mg/dL vs. 48.7 +/- 46.1 mg/dL; P = 0.039) and creatinine clearance <50 mL/min (10% vs. 37%; P = 0.06) were higher in patients without IHD.

CONCLUSIONS

In this work, metabolic syndrome was very common among patients with gout. Sixteen percent of the patients, although previously asymptomatic, had IHD, they all had metabolic syndrome. Gouty patients frequently first seek medical care from a rheumatologist. The rheumatologist can have an important role in detecting metabolic syndrome and risk factors for cardiovascular disease.

Cardiac imaging using nuclear medicine and postitron emission tomography

This article concentrates on specific issues that are of current interest in mainstream nuclear cardiology. These include developments in myocardial perfusion technique, the potential diagnostic benefits of ECG-gating and attenuation correction, nuclear imaging in the diagnosis of hibernating myocardium, and the cost-effectiveness of perfusion imaging in patients with suspected angina.

[Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal coronary arteries]

INTRODUCTION AND OBJECTIVES

Exercise-induced left bundle-branch block does not always denote the presence of underlying coronary artery disease. The aim of this study was to analyze the clinical characteristics and evolution of patients with rate-dependent left bundle-branch block.

PATIENTS AND METHOD

9,318 consecutive exercise stress studies were reviewed. The clinical characteristics and evolution (mean follow-up: 6.9 years) of 20 patients with exercise-induced left bundle-branch block in which coronary angiography had been performed were analyzed.

RESULTS

Eight out of 20 patients had normal coronary arteries (group A) and 12 had coronary artery disease (group B). Peak O2 consumption, peak myocardial O2 consumption, and heart rate when block appeared (132 20 vs. 95.4 23 beats/min; p = 0.002) were significantly higher in group A. Seven of the 8 patients with normal coronary arteries had chest pain coinciding with the first beat of left bundle-branch block. There were no deaths during follow-up in group A, but permanent left bundle-branch block appeared in 5 patients of this group who experienced disappearance of exercise-related pain. There were 3 deaths in group B and 2 patients had acute myocardial infarction during follow-up. One patient in each group developed atrioventricular block and required pacemaker implantation.

CONCLUSIONS

In contrast with patients with left bundle-branch block and coronary artery disease, the prognosis of patients with painful left bundle-branch block and normal coronary arteries is good. However, the development of permanent left bundle-branch block is frequent. Atrioventricular block, although rare, may occur.

[Physiologic evaluation of coronary circulation. Role of invasive and non invasive techniques]

For many years, the evaluation of the extent and severity of coronary artery disease has been mainly anatomical, carried out by coronary angiography. However, this technique has methodological limitations and interobserver variability is considerable. Quantification of coronary reserve with pressure guidewires and intracoronary Doppler now provides more precise physiologic evaluation of coronary circulation. Myocardial perfusion single proton emission computed tomography and echocardiography, combined with stress and/or pharmacological challenge testing, though they are only semiquantitative techniques, also offer appropriate complements to coronary angiography in the functional evaluation of coronary patients. The aim of this paper is to discuss the clinical value of these techniques.