technetium-tc-99m-tetrofosmin and Obesity

The introduction of a camera-based dose-reduction strategy in myocardial perfusion imaging (MPI) clinical setting entails the definition of objective and reproducible criteria for establishing the amount of activity to be injected.. The aim is to evaluate the impact of count statistics on the estimation of summed-scores (SS), end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF).. A significant difference between SS values of half-time and quarter-time stress scans was found for overweight group (P = .006). Post hoc test showed significant differences for ESV (P < .05), EDV (P < .01) and EF (P < .05) between half-time and quarter-time scans for both patient groups.. The reduction of the count-statistics to a quarter of the MPI reference influenced negatively the quantification in overweight patients. The decrease of radiopharmaceutical activity to 25% of the reference seems practicable for normal-weight patients, while it is more appropriate an activity reduction limited to 50% for overweight and obese patients.

Topics: Aged; Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; Coronary Artery Disease; Female; Humans; Image Enhancement; Image Interpretation, Computer-Assisted; Male; Myocardial Perfusion Imaging; Obesity; Organophosphorus Compounds; Organotechnetium Compounds; Radiation Exposure; Radiation Protection; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Stroke Volume

There are no data regarding the long-term prognostic value of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in obese patients. The aim of this study was to examine the value of stress (99m)Tc-tetrofosmin MPI findings for the prediction of very long-term outcome in obese patients.. The study population consisted of 261 patients with a body mass index ≥30 kg/m(2) who underwent exercise or pharmacological stress (99m)Tc-tetrofosmin MPI for the assessment of known or suspected coronary artery disease. Endpoints during follow-up were all-cause mortality, cardiac death, nonfatal infarction, and coronary revascularization. Kaplan-Meier survival cures were constructed and univariate and multivariate analyses were performed to identify predictors of very long-term outcome.. The mean age was 59 ± 10 years, 42% of the patients was male, and the body mass index was on average 37 ± 7 kg/m(2). MPI findings were normal in 109 patients (42%). Myocardial perfusion abnormalities were fixed in 62 patients (24%) and reversible in 90 patients (34%). During a median 12-year follow-up, 91 (35%) patients died, and 27 (10%) had a nonfatal myocardial infarction. Survival curves were compared using the log-rank test at subsequent follow-up durations. Obese patients with a normal stress (99m)Tc-tetrofosmin study had a significantly better prognosis as compared with those with an abnormal study, up to 6 years after the test was performed.. Stress (99m)Tc-tetrofosmin MPI provides valuable prognostic information for the prediction of outcome in obese patients. Obese patients with a normal stress (99m)Tc-tetrofosmin study have a significantly better prognosis as compared with those with an abnormal study, up to 6 years after the test is performed.

Topics: Comorbidity; Coronary Artery Disease; Female; Humans; Incidence; Longitudinal Studies; Male; Middle Aged; Myocardial Perfusion Imaging; Netherlands; Obesity; Organophosphorus Compounds; Organotechnetium Compounds; Prognosis; Radiopharmaceuticals; Reproducibility of Results; Risk Assessment; Sensitivity and Specificity; Survival Analysis; Survival Rate; Tomography, Emission-Computed, Single-Photon

The American Society of Nuclear Cardiology and the Society of Nuclear Medicine state that incorporation of attenuation-corrected (AC) images in myocardial perfusion scintigraphy (MPS) will improve image quality, interpretive certainty, and diagnostic accuracy. However, commonly used software packages for MPS usually include normal stress databases for non-attenuation corrected (NC) images but not for attenuation-corrected (AC) images. The aim of the study was to develop and compare different normal stress databases for MPS in relation to NC vs. AC images, male vs. female gender, and presence vs. absence of obesity. The principal hypothesis was that differences in mean count values between men and women would be smaller with AC than NC images, thereby allowing for construction and use of gender-independent AC stress database.. Normal stress perfusion databases were developed with data from 126 male and 205 female patients with normal MPS. The following comparisons were performed for all patients and separately for normal weight vs. obese patients: men vs. women for AC; men vs. women for NC; AC vs. NC for men; and AC vs. NC for women.. When comparing AC for men vs. women, only minor differences in mean count values were observed, and there were no differences for normal weight vs. obese patients. For all other analyses major differences were found, particularly for the inferior wall.. The results support the hypothesis that it is possible to use not only gender independent but also weight independent AC stress databases.

Topics: Adult; Aged; Aged, 80 and over; Body Weight; Coronary Artery Disease; Databases, Factual; Exercise Test; Female; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Obesity; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Reference Values; Reproducibility of Results; Sex Factors; Software; Tomography, Emission-Computed, Single-Photon

Obesity is a major heath problem associated with increased cardiovascular mortality. There are currently no data to support a role for stress imaging techniques in the risk stratification of obese patients. The aim of this study was to assess the independent value of stress 99mTc-tetrofosmin SPECT in predicting mortality and hard cardiac events in obese patients.. We studied 265 patients with a body mass index greater than 30 kg/m2 by exercise or dobutamine stress 99mTc-tetrofosmin myocardial perfusion tomography. Endpoints during follow-up were cardiac death and death of any cause.. The mean patient age (+/-SD) was 59 +/- 10 y, and 110 of the patients were men (42%). The mean body mass index was 37 +/- 7 kg/m2. Scan findings were normal in 113 patients (43%). Myocardial perfusion abnormalities were fixed in 62 patients (23%) and reversible in 90 patients (34%). During a mean follow-up period of 5.5 +/- 2 y, 41 patients (15%) died. Death was considered cardiac in 22 patients (8%). Nonfatal myocardial infarction occurred in 20 patients (7.5%). The annual cardiac death rate was 0.6% in patients with normal perfusion and 3.3% in patients with abnormal perfusion. Patients with a multiple-vessel distribution of abnormalities had a higher cardiac death rate than did patients with a single-vessel distribution (4.1% vs. 2.5%, P < 0.05). The annual mortality rate was 1.3% in patients with normal perfusion and 4.2% in patients with abnormal perfusion. In a multivariate analysis, perfusion abnormalities were independently predictive of cardiac mortality (risk ratio, 3.2; 95% confidence interval, 1.5-6.7) and overall mortality (risk ratio, 2.7; 95% confidence interval, 1.4-4.3).. Stress 99mTc-tetrofosmin myocardial perfusion imaging is a useful tool for predicting cardiac and overall mortality in obese patients.

Topics: Aged; Body Mass Index; Cardiotonic Agents; Dobutamine; Female; Humans; Male; Middle Aged; Myocardial Reperfusion; Myocardium; Obesity; Organophosphorus Compounds; Organotechnetium Compounds; Prognosis; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon