Area of ischemia assessed by physicians and software packages from myocardial perfusion scintigrams.

BACKGROUND: The European Society of Cardiology recommends that patients with >10% area of ischemia should receive revascularization. We investigated inter-observer variability for the extent of ischemic defects reported by different physicians and by different software tools, and if inter-observer variability was reduced when the physicians were provided with a computerized suggestion of the defects. METHODS: Twenty-five myocardial perfusion single photon emission computed tomography (SPECT) patients who were regarded as ischemic according to the final report were included. Eleven physicians in nuclear medicine delineated the extent of the ischemic defects. After at least two weeks, they delineated the defects again, and were this time provided a suggestion of the defect delineation by EXINI HeartTM (EXINI). Summed difference scores and ischemic extent values were obtained from four software programs. RESULTS: The median extent values obtained from the 11 physicians varied between 8% and 34%, and between 9% and 16% for the software programs. For all 25 patients, mean extent obtained from EXINI was 17.0% (± standard deviation (SD) 14.6%). Mean extent for physicians was 22.6% (± 15.6%) for the first delineation and 19.1% (± 14.9%) for the evaluation where they were provided computerized suggestion. Intra-class correlation (ICC) increased from 0.56 (95% confidence interval (CI) 0.41-0.72) to 0.81 (95% CI 0.71-0.90) between the first and the second delineation, and SD between physicians were 7.8 (first) and 5.9 (second delineation). CONCLUSIONS: There was large variability in the estimated ischemic defect size obtained both from different physicians and from different software packages. When the physicians were provided with a suggested delineation, the inter-observer variability decreased significantly.

Computer-aided diagnosis system outperforms scoring analysis in myocardial perfusion imaging.

BACKGROUND: The aim of this myocardial perfusion imaging (MPI) study was to compare the diagnostic performance of two computer-aided diagnosis (CAD) systems, EXINI Heart(TM) (EXINI), and PERFEX(TM) (PERFEX) Emory Cardiac Toolbox (ECT), and the summed stress score (SSS) values from both software packages. METHODS: We studied 1,052 consecutive patients who underwent 2-day stress/rest (99m)Tc-sestamibi MPI studies. The reference standard classifications for the MPI studies were obtained from three experienced physicians who separately classified all cases regarding the presence or absence of ischemia and/or infarction. Automatic processing was carried out using EXINI and PERFEX to obtain CAD results and SSS values based on the 17-segment model. RESULTS: The three experts' classifications showed ischemia in 257 patients and abnormal studies, i.e., either ischemia or infarction or both, in 318 patients. Accuracy was significantly higher in EXINI than in PERFEX, regarding both the detection of ischemia (87.4 vs 77.6%; P < 0.0001) and the detection of abnormal studies (91.6 vs 67.9%; P < 0.0001). EXINI's CAD system showed a higher specificity than its SSS values (86.8 vs 73.6%; P < 0.0001) at the same level of sensitivity. CONCLUSIONS: EXINI demonstrated greater diagnostic accuracy for detection of ischemia and abnormal studies than did PERFEX. EXINI CAD also outperformed its SSS analysis.

Diagnostic evaluation of three cardiac software packages using a consecutive group of patients.

PURPOSE: The aim of this study was to compare the diagnostic performance of the three software packages 4DMSPECT (4DM), Emory Cardiac Toolbox (ECTb), and Cedars Quantitative Perfusion SPECT (QPS) for quantification of myocardial perfusion scintigram (MPS) using a large group of consecutive patients. METHODS: We studied 1,052 consecutive patients who underwent 2-day stress/rest 99mTc-sestamibi MPS studies. The reference/gold-standard classifications for the MPS studies were obtained from three physicians, with more than 25 years each of experience in nuclear cardiology, who re-evaluated all MPS images. Automatic processing was carried out using 4DM, ECTb, and QPS software packages. Total stress defect extent (TDE) and summed stress score (SSS) based on a 17-segment model were obtained from the software packages. Receiver-operating characteristic (ROC) analysis was performed. RESULTS: A total of 734 patients were classified as normal and the remaining 318 were classified as having infarction and/or ischemia. The performance of the software packages calculated as the area under the SSS ROC curve were 0.87 for 4DM, 0.80 for QPS, and 0.76 for ECTb (QPS vs. ECTb p = 0.03; other differences p < 0.0001). The area under the TDE ROC curve were 0.87 for 4DM, 0.82 for QPS, and 0.76 for ECTb (QPS vs. ECTb p = 0.0005; other differences p < 0.0001). CONCLUSION: There are considerable differences in performance between the three software packages with 4DM showing the best performance and ECTb the worst. These differences in performance should be taken in consideration when software packages are used in clinical routine or in clinical studies.

Increased plasma concentrations of N-terminal pro-B-type natriuretic peptide in patients with mild primary hyperparathyroidism.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is associated with heart disease. The aims of the present study were to evaluate how cardiac function and secretion of N-terminal pro-B-type natriuretic peptide (NT-proBNP) correlate in patients with mild PHPT, and how the plasma level of NT-proBNP is influenced by cure of the parathyroid disease. DESIGN AND PATIENTS: Forty-two patients with PHPT without symptoms of heart disease were examined before and 1 year after curative parathyroidectomy. MEASUREMENTS: Plasma or serum concentrations of NT-proBNP, calcium, PTH, creatinine, oestradiol, testosterone and SHBG were measured. Cardiac function was evaluated by equilibrium radionuclide angiography (ERNA). RESULTS: At baseline, NT-proBNP levels correlated negatively with systolic function [left ventricular ejection fraction (LVEF), P < 0.001]. Twelve per cent of the patients had NT-proBNP levels above normal reference values preoperatively. One year postoperatively, the corresponding proportion was 21%. The mean plasma concentration of NT-proBNP increased after parathyroidectomy (P < 0.01) in parallel with a dip in diastolic function (peak filling rate, P < 0.05) and a falling trend in systolic function (LVEF, P = 0.08). The postoperative percentage changes in circulating NT-proBNP and total oestradiol correlated positively (P < 0.05). CONCLUSIONS: Patients with mild PHPT and normal renal function may have high levels of circulating NT-proBNP despite the absence of symptomatic heart disease. Cure of the parathyroid disease is followed by a further increase in NT-proBNP secretion in parallel with ERNA measures, indicating subclinical changes in heart function. These results are in line with data indicating an association between PHPT and increased risk of premature death.

Cardiac dysfunction in mild primary hyperparathyroidism assessed by radionuclide angiography and echocardiography before and after parathyroidectomy.

BACKGROUND: Primary hyperparathyroidism (PHPT) is associated with increased cardiovascular morbidity for reasons that are incompletely understood. The present study was undertaken to evaluate the effects of parathyroidectomy on cardiac function especially in patients with mild PHPT. METHODS; Fifty patients with mild PHPT (serum calcium, 2.55 to 2.95 mmol/L) were randomized to parathyroidectomy either directly (group A) or after 1 year of observation (group B). Equilibrium radionuclide angiography (ERNA) at rest and at exercise was performed in addition to echocardiography on all patients at inclusion in the study and 1 and 2 years later. RESULTS: Left ventricular mass index was larger (P <.05) in group B compared with group A after 2 years and showed significant correlation to the serum concentration of parathyroid hormone (but not serum calcium) after 1 year. ERNA showed transient subclinical changes in both systolic and diastolic function parameters after parathyroidectomy (decrease of left ventricular ejection fraction and peak filling rate, with return to preoperative levels within 1 year). CONCLUSIONS: Combined evaluation by ERNA and echocardiography has shown previously unknown aspects of parathyroid/myocardial interaction, which is consistent with an inotropic influence exerted by parathyroid hormone, and is in favor of early surgical treatment for PHPT irrespective of serum calcium levels.