Technetium-99m Tetrofosmin Myocardial Perfusion Research Articles

Prediction of long-term (> 10 year) cardiovascular outcomes in heart transplant recipients: Value of stress technetium-99m tetrofosmin myocardial perfusion imaging

BackgroundMyocardial 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. MethodsThe study population consisted of 166 HTx recipients (mean age 54 ± 10 years, 84% male) who underwent exercise or dobutamine stress 99mTc-tetrofosmin SPECT MPI for the assessment of CAV. An abnormal SPECT MPI was defined as the presence of a fixed or a reversible perfusion defect. Endpoints were all-cause mortality, cardiac mortality, and non-fatal myocardial infarction (MI). ResultsMPI 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 99mTc-tetrofosmin SPECT MPI had a significantly better prognosis as compared with those with an abnormal study, up to 5 years after the initial test. The presence of a reversible perfusion defect was a significant predictor of all-cause mortality, cardiac mortality, and major cardiac events, during the entire follow-up period. ConclusionsStress 99mTc-tetrofosmin SPECT MPI provides valuable prognostic information for the prediction of long-term outcome in HTx recipients. Patients with a normal stress 99mTc-tetrofosmin SPECT MPI have a significantly better prognosis as compared with those with an abnormal study, up to 5 years after initial testing.

Quantitative iodine-123-metaiodobenzylguanidine (MIBG) SPECT imaging in heart failure with left ventricular systolic dysfunction: Development and validation of automated procedures in conjunction with technetium-99m tetrofosmin myocardial perfusion SPECT

BackgroundThe purpose of this study was to develop and validate new approaches to quantitative MIBG myocardial SPECT imaging in heart failure (HF) subjects. Methods and resultsQuantitative MIBG myocardial SPECT analysis methods, alone and in conjunction with 99mTc-tetrofosmin perfusion SPECT, were adapted from previously validated techniques for the analysis of SPECT and PET perfusion imaging. To account for underestimation of MIBG defect severity in subjects with global reduction in uptake, a mixed reference database based on planar heart/mediastinum (H/M) ratio categories was used. Extent and severity of voxel-based defects and number of myocardial segments with significant dysinnervation (derived score ≥2) were determined. MIBG/99mTc-tetrofosmin mismatch was quantified using regions with preserved innervation as the reference for scaling 99mTc-tetrofosmin voxel maps. Quantification techniques were tested on studies of 619 ischemic (I) and 319 non-ischemic (NI) HF subjects. Using all analytical techniques, IHF subjects had significantly greater and more severe MIBG SPECT abnormalities compared with NIHF subjects. Innervation/perfusion mismatches were also larger in IHF subjects. Findings were consistent between voxel- and myocardial-segment-based quantitation methods. ConclusionsMultiple objective methods for quantitation of MIBG SPECT imaging studies provided internally consistent results for distinguishing the different patterns of uptake between IHF and NIHF subjects.

Long-term prognostic value of exercise technetium-99m tetrofosmin myocardial perfusion single-photon emission computed tomography

BackgroundExercise 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) is a useful tool for short- and medium-term risk stratifications. Currently, the long-term prognostic application of this technique has not been evaluated. Methods and ResultsExercise 99mTc-tetrofosmin was performed in 655 consecutive patients. Ten patients who underwent revascularization <60 days after nuclear testing were excluded from the analysis. The present data are based on 638 patients with complete follow-up. An abnormal SPECT study was defined as the presence of fixed and/or reversible perfusion defects. End points were cardiac death, nonfatal infarction, and late coronary revascularization. A total of 344 (54%) patients had an abnormal SPECT study. Perfusion defects included fixed defects alone in 186 patients (29%) and reversible defects in 158 (25%) patients. During a mean follow-up of 11.0 ± 3.3 years, 174 (27%) patients died (all-cause mortality). Nonfatal myocardial infarction occurred in 76 (12%) patients, and late coronary revascularization was performed in 194 (30%) patients. Univariable and multivariable Cox proportional hazard regression analyses showed that exercise 99mTc-tetrofosmin SPECT provided prognostic information incremental to clinical data and exercise test data. Patients with a normal SPECT had a relatively favorable long-term prognosis, in contrast to patients with an abnormal study who had a significantly increased risk of cardiac events. The SPECT parameters abnormal scan, reversible defect, and summed rest score were strong predictors of long-term outcome. ConclusionExercise 99mTc-tetrofosmin myocardial perfusion SPECT has an incremental long-term prognostic value over clinical and stress test parameters for the prediction of major adverse cardiac events.

Incidental detection of apical hypertrophic cardiomyopathy by myocardial perfusion imaging

Echocardiography plays a central role in the diagnosis of hypertrophic cardiomyopathy (HCM). However, apical involvement of HCM may be missed because of foreshortening and inadequate clinical suspicion. These patients may be referred for single-photon emission computed tomography imaging. We present three cases of HCM predominantly involving the cardiac apex, whose diagnosis was first suspected on myocardial perfusion imaging. These patients were referred for chest pain syndromes to exclude significant coronary artery disease. All were undiagnosed on initial routine transthoracic echocardiography, and none were specifically suspected by the referring clinicians. All cases underwent an adenosine stress rest technetium-99m tetrofosmin myocardial perfusion protocol, and were subsequently referred for transpulmonary contrast echocardiography. Single-photon emission computed tomography imaging revealed increased tracer uptake in all cases, most marked in the apical myocardium. Inferior wall ischaemia was detected in one case, consistent with a coronary stenosis seen at angiography. Apical hypokinesia was noted in two patients on gated studies. Contrast echocardiography confirmed the diagnosis of HCM with apical involvement in all cases. Echocardiography is the first-line imaging technique for the diagnosis of HCM, but apical involvement may be missed unless a contrast study is performed. The presence of increased apical tracer uptake on perfusion imaging should alert the referring physician to the possibility of apical HCM, irrespective of earlier echocardiographic findings.

Vasodilator Stress Impairs the Left Ventricular Function Obtained With Gated Single-Photon Emission Computed Tomography in Patients With Known or Suspected Coronary Artery Disease

Transient ischemic dilatation (TID) and post-stress dysfunction of the left ventricle (LV) are important markers of severe coronary artery disease (CAD). To clarify the effects of stressor type on TID and post-stress LV dysfunction, changes in LV measurements were compared between patients with exercise- or vasodilator-induced stress. The 689 patients referred for technetium-99m tetrofosmin myocardial perfusion imaging were included. Patients were stressed with either a vasodilator (n=236) or exercise (n=453). LV measurements were obtained with ECG-gated SPECT. LV end-diastolic and end-systolic volume indexes (LVEDVI, LVESVI) increased and LV ejection fraction (LVEF) decreased after stress in the vasodilator-stress group. Vasodilator-stress and the summed difference score (SDS) were independent variables that decreased LVEF after stress. Even in patients without reversible defects, vasodilator-stress impaired LV function. There were no differences in the stress-to-rest ratios of LVEDVI (rEDV) and LVESVI (rESV) among patients with normal myocardial perfusion, fixed defects and reversible defects in the vasodilator-stress group, whereas in the exercise-stress group, rESV was significantly higher in the patients with reversible defects than in those without reversible defects. Within the vasodilator-stress group, neither rEDV nor rESV correlated with the SDS. Vasodilator-stress by itself decreases LVEF after stress. TID should be carefully interpreted when vasodilator-stress is used to detect severe CAD.

Reduction of infracardiac intestinal activity by a small amount of soda water in technetium-99m tetrofosmin myocardial perfusion scintigraphy with adenosine stress

In technetium (Tc)-99m myocardial perfusion imaging (MPI), intestinal activity often interferes with the assessment of myocardial perfusion of the inferior wall. We examined whether a small amount of soda water prevents intestinal activity and improves image quality of the inferior wall in Tc-99m tetrofosmin MPI. Ninety-five patients referred for 1-day rest/stress Tc-99m tetrofosmin MPI were assigned to one of two groups automatically, according to the date when they underwent MPI: the soda water group (n = 63) ingested 100 mL soda water just before image acquisition after adenosine stress, and the control group (n = 32) underwent no intervention. The frequency of intestinal activity was assessed visually on planar images. The inferior myocardial wall and the abdominal activity adjacent to the myocardium were assessed quantitatively on three different planar images during stress, and the mean inferior wall-to-abdomen (I/A) count ratio was calculated. The frequency of intestinal activity was 69.8% in the soda water group, and 90.6% in the control group (P = .038). The I/A count ratio was significantly higher in the soda water group than in the control group (1.98 +/- 0.51 vs 1.50 +/- 0.35, respectively, P < .0001, +/- SD). The intake of 100 mL of soda water improves intestinal activity and improves the image quality of the inferior wall.

Prognostic utility of normal technetium99m tetrofosmin myocardial perfusion SPECT in Asian women compared to men

Prognostic utility of normal technetium99m tetrofosmin myocardial perfusion SPECT in Asian women compared to men

Prediction of all-cause mortality in women with known or suspected coronary artery disease by stress technetium-99m tetrofosmin myocardial perfusion imaging

We studied the incremental value of stress technetium-99m tetrofosmin imaging for predicting all-cause mortality in 503 women (aged 58 ± 12 years) with known or suspected coronary artery disease. The annual mortality rate was 1.4% with normal perfusion and 4% with abnormal perfusion (p <0.01) during a follow-up of 3.5 ± 1.2 years. In an incremental multivariate analysis model, clinical predictors of mortality were age, diabetes mellitus, smoking, and a lower systolic blood pressure during stress. An abnormal scan was incremental to clinical data in predicting mortality.

Incremental value of exercise technetium-99m tetrofosmin myocardial perfusion single-photon emission computed tomography for the prediction of cardiac events

This study assessed the incremental prognostic implications of normal and equivocal exercise technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) and sought to determine its incremental prognostic value, impact on patient management and cost implications.The prognostic implications of Tc-99m sestamibi SPECT are not well defined, and risk stratification using this test has not been explored.We studied 1,702 patients referred for exercise Tc99m sestamibi SPECT who were followed up for a mean (±SD) of 20 ± 5 months. Patients with previous percutaneous transluminal coronary angioplasty or coronary artery bypass surgery were excluded. The SPECT studies were assessed using semiquantitative visual analysis. Cardiac death and myocardial infarction were considered “hard” events, and coronary angioplasty and bypass surgery >60 days after testing were considered “soft” events.Of the 1,702 patients studied, 1,131 had normal or equivocal scan results. A total of 10 events occurred in this group (1 cardiac death and 1 myocardial infarction [0.2% hard events]; 4 coronary angioplasty and 4 bypass surgery procedures [0.7% soft events]). The rates of hard events and referral to catheterization after SPECT were similarly low in patients with a low (< 0.15), intermediate (0.15 to 0.85) and high (>0.85) post-exercise treadmill test (ETT) likelihood of coronary artery disease. With respect to scan type, patients with normal, probably normal or equivocal scan results had similarly low hard event rates. In the 571 patients with abnormal scan results, there were 43 hard events (7.5%) and 42 soft events (7.4%) (p < 0.001 vs. 1,131 patients with normal scan results for both). When the complete spectrum of scan responses was considered, SPECT provided incremental prognostic value in all patient subgroups analyzed. However, the nuclear scan was cost-effective only in patients with interpretable exercise ECG responses and an intermediate to high post-ETT likelihood of coronary artery disease and in those with uninterpretable exercise ECG responses and an intermediate to high pre-ETT likelihood of coronary artery disease.Normal or equivocal exercise Tc-99m sestamibi study results are associated with a benign prognosis, even in patients with a high likelihood of coronary artery disease. Although incremental prognostic value is added by nuclear testing in all patient subgroups, a testing strategy incorporating nuclear testing proved to be cost-effective only in the groups with an intermediate to high likelihood of coronary artery disease before scanning.

Poor agreement between dipyridamole-stress technetium-99m-tetrofosmin myocardial perfusion single photon emission computed tomography and two-dimensional echocardiography in Kawasaki disease

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.

Incremental value of exercise technetium-99m tetrofosmin myocardial perfusion single-photon emission computed tomography for the prediction of cardiac events

Technetium-99m (Tc-99m) tetrofosmin single-photon emission computed tomography (SPECT) is a useful alternative to thallium-201 scintigraphy for the assessment of myocardial perfusion. This study assessed the incremental value of exercise Tc-99m tetrofosmin SPECT for the prediction of cardiac events in patients with known or suspected coronary artery disease. Exercise Tc-99m tetrofosmin SPECT imaging was performed in 655 consecutive patients. Follow-up was successful in 648 patients (98.9%). Ten patients underwent early coronary revascularization and were excluded. End points were cardiac death, nonfatal infarction, and late (>60 days) coronary revascularization. An abnormal study was defined as the presence of fixed and/or reversible perfusion defects. A summed stress score (SSS) was derived to estimate the extent and severity of perfusion defects. An abnormal scan was detected in 344 patients (54%). During a mean follow-up period of 4 ± 1.3 years, 56 patients (9%) died (22 cardiac deaths). Nonfatal myocardial infarction occurred in 19 patients (3%), and 89 patients (14%) underwent late coronary revascularization. An abnormal scan was an independent predictor of cardiac death (hazard ratio 3.5, confidence intervals [CI] 1.1 to 12.2) and provided incremental information over clinical and exercise test data (log-likelihood −133 to −125, p <0.05). The SSS provided incremental prognostic information over clinical data as well (log-likelihood −133 to −127, p <0.05) (hazard ratio 1.23, CI 1.10 to 1.38). An abnormal scan (hazard ratio 3.3, CI 1.1 to 12.2)) and the SSS (hazard ratio 1.25, CI 1.07 to 1.45)) were powerful independent predictors of the combined end point of any cardiac event. Thus, exercise Tc-99m tetrofosmin myocardial perfusion SPECT provides information incremental to clinical data for the prediction of cardiac events in patients with known or suspected coronary artery disease.

Single photon emission computed tomography of technetium-99m tetrofosmin myocardial perfusion imaging in patients with systemic lupus erythematosus--a preliminary report.

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.

Technetium-99m tetrofosmin myocardial perfusion single photon emission computed tomography in syndrome X: a preliminary report.

Syndrome X is used to describe patients with chest pain and a normal coronary angiogram. We reviewed technetium-99m tetrofosmin (Tc-99m TF) myocardial perfusion single photon emission computed tomography (SPECT) results and clinical data of 43 syndrome X patients and 30 healthy controls with normal left ventricular ejection fraction and no cardiac abnormalities. The Tc-99m TF myocardial perfusion SPECT results showed 12 (27.9%) syndrome X patients had normal myocardial perfusion and 31 (72.1%) had abnormal myocardial perfusion, including 6 (14.0%) patients with fixed defects. 20 (46.5%) patients with transient defects, and 5 (11.6%) patients with reverse defects. The results of exercise ECG were not related to perfusion defects in Tc-99m TF myocardial perfusion SPECT. In contrast, all of the 30 (100.0%) healthy controls had normal myocardial perfusion SPECT results. We conclude that abnormal Tc-99m TF myocardial perfusion SPECT is common in syndrome X and does not correlate well with the exercise ECG. However, further studies with larger case numbers and long term follow up in patients with myocardial events are necessary to support our findings.

Prediction of mortality in heart transplant recipients by stress technetium-99m tetrofosmin myocardial perfusion imaging

Cardiac allograft vasculopathy is a major cause of mortality in heart transplant recipients. The aim of this study was to assess the prognostic value of stress myocardial perfusion imaging in heart transplant recipients. We studied 166 patients (age 54 ± 10 years, 140 men) by symptom-limited bicycle exercise or dobutamine (up to 40 μg/kg/min) stress myocardial perfusion imaging 7.4 ± 2.5 years after heart transplantation. An intravenous dose of 370 MBq of technetium-99m tetrofosmin was injected at peak stress and 24 hours after the stress test. An abnormal test was defined as reversible or fixed perfusion defects. Perfusion abnormalities were detected in 55 patients (33%). During a median follow-up of 2.5 years, 54 deaths (33%) occurred, 16 of which were due to cardiac causes. The incidence of perfusion abnormalities was higher in patients with subsequent cardiac death than in patients without subsequent cardiac death (69% vs 29%, p = 0.01). In an incremental multivariate Cox analysis, cardiac death was not predicted by age, gender, duration of transplantation, number of rejection episodes, or cytomegalovirus infection. In the next step, stress test parameters were added. The peak rate-pressure product was the only significant predictor at this step (risk ratio 0.84, 95% confidence interval 0.73 to 0.97, chi-square 7.7, p = 0.006). In the final step, the presence of abnormal myocardial perfusion was an independent predictor of cardiac death (risk ratio 3.5, 95% confidence interval 1.6 to 11.7, chi-square 4.7, incremental to clinical and stress test variables, p = 0.01). It is concluded that stress myocardial perfusion imaging with technetium-99m tetrofosmin single-photon emission computed tomography provides incremental data for the prediction of cardiac death in heart transplant recipients.

Lung Uptake of Technetium-99m Tetrofosmin in Healthy Subjects Is Related to Smoking Habits

To determine the influence of smoking on lung uptake of technetium-99m tetrofosmin (Tc-TF) during myocardial perfusion imaging, we examined 50 healthy subjects with normal myocardial perfusion single photon emission computed tomography findings, normal coronary angiograms, and no evidence of left ventricular hypertrophy. The 50 healthy subjects were divided into two groups. Group 1: 25 healthy subjects had smoking histories of at least 10 pack-years. Group 2: 25 healthy subjects were nonsmokers. Lung to heart ratios (L/H ratios) calculated from anterior planar images during exercise and rest states of Tc-TF myocardial perfusion imaging were obtained for all of the 50 healthy subjects. L/H ratios calculated from Tc-TF myocardial perfusion imaging in smokers were significantly higher than in nonsmokers during both exercise and rest states. However, no significant difference in L/H ratios was found between exercise and rest states in smokers and nonsmokers. In addition, a positive but nonsignificant correlation was found between smoking pack-years and either rest or exercise L/H ratios. When L/H ratios are used as a clinical diagnostic tool in Tc-TF myocardial perfusion imaging, we must consider that L/H ratios in smokers are higher than in nonsmokers.

Discordance between dipyridamole stress technetium-99m tetrofosmin single photon emission computed tomography and coronary angiography in patients with Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis syndrome of unknown etiology that mainly affects the coronary arteries. The purpose of this study was to assess the agreement between dipyridamole stress technetium-99m tetrofosmin (Tc-TF) myocardial perfusion single photon emission computed tomography (SPECT) and coronary angiography in these patients. Twenty-nine children with KD were included in this study. All of the 29 children also received dipyridamole stress Tc-TF myocardial perfusion SPECT within 1 month of their coronary angiographic studies. The results showed that (1) 89.7% of children had negative coronary angiographic findings without significant coronary stenoses, and 10.3% of children had positive coronary angiographic findings with significant coronary stenosis; (2) 44.8% of children had negative Tc-TF myocardial perfusion SPECT findings without abnormal myocardial perfusion, and 55.2% of children had positive Tc-TF myocardial perfusion SPECT findings with abnormal myocardial perfusion; (3) 44.8% of children had both normal coronary angiographic and Tc-TF myocardial perfusion SPECT findings, and 10.3% of children had both abnormal coronary angiographic and Tc-TF myocardial perfusion SPECT findings; and (4) There was no significant agreement between coronary angiographic and Tc-TF myocardial perfusion SPECT findings. We concluded that poor agreement exists between coronary angiographic and Tc-TF myocardial perfusion SPECT findings with coronary stenoses and abnormal myocardial perfusion in children with KD.

Accuracy of technetium-99m tetrofosmin myocardial perfusion imaging in the detection of spontaneous recanalization in patients with acute anterior myocardial infarction

To avoid the haemorrhagic risk of unnecessary thrombolysis in acute myocardial infarction (MI), early and precise diagnosis of spontaneous recanalization (SR) of the infarct-related artery is required. To clarify the accuracy of technetium-99m tetrofosmin myocardial single-photon emission tomography (SPET) in the detection of SR in patients with acute anterior MI, electrocardiography (ECG), echocardiography and (99m)Tc-tetrofosmin SPET imaging were performed in 49 patients with acute anterior MI before emergency coronary angiography. Defect score was calculated as the sum of the perfusion defects of each segment: from 3 (complete defect) to 0 (normal perfusion). Echocardiographic asynergic score (the sum of asynergic grades) and the greatest ST elevation of the 12-lead ECG on admission were also measured. SR was defined as Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow on emergency coronary angiography. Defect score in 11 patients with SR (9.2±3.7) was significantly lower than that in 38 patients without SR (18.5±5.0) (P<0.001), whereas there were no significant differences in asynergic score and ST elevation between the two groups. From the receiver operating characteristic curves, the optimal cut-off points of defect score, asynergic score and ST elevation for the detection of SR were calculated to be 12, 13 and 3.5, respectively. The sensitivity and specificity of the scintigraphic defect score (91% and 89%) were significantly higher than those of the asynergic score (64% and 68%) and ST elevation (73% and 71%). Thus, (99m)Tc-tetrofosmin SPET imaging on admission is a very accurate method for the detection of SR in patients with acute anterior MI.

Left Ventricular Function and Infarct Size 20 Months after Primary Angioplasty for Acute Myocardial Infarction

Objective –To study changes in left ventricular function and infarct size during long-term follow-up after acute myocardial infarction treated with primary angioplasty. Design –From 1996 to 1998, 100 consecutive patients were treated with primary angioplasty for acute ST-elevation myocardial infarction. Angioplasty was successful in 95% of the patients. Global left ventricular ejection fraction (LVEF) was determined by radionuclide ventriculography before discharge, after 6 weeks and after a mean follow-up time of 20 months. Infarct size was assessed by technetium 99m-tetrofosmin myocardial perfusion tomography (SPECT) at rest, performed at the same time intervals. Results –Mean LVEF was 56% at discharge, 55% after 6 weeks and 57% after 20 months of follow-up. No significant improvement in LVEF was observed. Only 8% of the patients at follow-up had LVEF lower than 40%. After 1 week, a mean perfusion defect of 19% was measured by SPECT. After 6 weeks and 20 months of follow-up, the mean perfusion defects were reduced to 14% ( p < 0.001) and 15%, respectively. Conclusion –Left ventricular function was well preserved with a mean LVEF of 57% 20 months after primary angioplasty for acute myocardial infarction. No significant change in LVEF was observed from 1 week after angioplasty to follow-up. Infarct sizes as assessed by SPECT imaging with tetrofosmin were reduced from 1 to 6 weeks, but did not change further during long-term follow-up. The reduction in the perfusion defects over time was probably due to gradual relief of stunning.

&lt;sup&gt;99m&lt;/sup&gt;Tc-tetrofosminによる胆嚢の高集積が心筋SPECT画像に及ぼす影響と改善法についての検討

&lt;sup&gt;99m&lt;/sup&gt;Tc-tetrofosminによる胆嚢の高集積が心筋SPECT画像に及ぼす影響と改善法についての検討

No gender bias in referral for coronary angiography after myocardial perfusion scintigraphy with technetium-99m tetrofosmin

Background. Several studies have shown that the application of diagnostic and invasive procedures varies between men and women. The purpose of this study was to assess if referral for coronary angiography after technetium-99m tetrofosmin myocardial perfusion scintigraphy in 616 patients with undiagnosed chest pain might demonstrate gender bias. Methods and Results. The primary end point for this study was coronary angiography within 90 days of myocardial perfusion scintigraphy. Women had more normal perfusion images than men (207 [70.9%] vs 160 [50.5%], P < .05). Of 242 patients with abnormal images (157 men, 85 women), 28 men (17.7%) and 17 women (20.0%) were referred for further invasive testing ( P = not significant). Referral for coronary angiography increased relative to the number of defects. Univariate analysis showed that reversible and persistent defects were the most predictive variables for referral to coronary angiography (odds ratio [OR] 5.45, 95% confidence interval [CI] 3.10–9.58, P < .001, and OR 2.67, 95% CI 1.52–4.67, P = .001, respectively). More importantly, multivariate analysis showed that reversible perfusion defects (OR 4.77, 95% CI 2.48–9.17, P < .001) and persistent perfusion defects (OR 2.14, 95% CI 1.11–4.14, P = .02) were predictive of subsequent coronary angiography. No significant association between gender and subsequent coronary angiography was found both in univariate and multivariate logistic regression analysis (OR 0.64, 95% CI 0.37–1.12, P = .12, and OR 0.70, 95% CI 0.36–1.36, P = .28, respectively). Conclusions. Our study reveals that after correction for the presence and the severity of myocardial perfusion abnormalities, men and women were referred to coronary angiography at a similar rate. Thus, based on the results of technetium-99m tetrofosmin myocardial perfusion imaging, no substantial evidence for a gender-related bias could be found in the referral for further invasive testing.