Background: Left ventricular ejection fraction (LVEF) is an important diagnostic and prognostic parameter in coronary artery disease (CAD). Gated SPECT myocardial perfusion imaging (GSMPI) is a popularly used for non invasive quantitative assessment of LVEF. Gated SPECT blood pool imaging (GSBPI) being a radionuclide ventriculography technique is gold standard as well as technically comparable to GSMPI.Good correlation of these two methods for measurement of LVEF is reported by using correlation coefficients. Bland and Altman show the inappropriateness of correlation coefficient for comparison analysis of measurement methods. The objective was to assess agreement between GSMPI and GSBPI for measurement of LVEF in CAD.Materials and Methods: Study was done in 27 patients (24 men/ 3 women) with CAD. The mean age was 54.2±6.2 years ranging from 32 to 68 years. All patients underwent GSMPI and GSBPI with a gap of three to seven days. LVEF measured in rest phase of one day stress-est GSMPI was compared with LVEF measured by GSBPI performed at rest. Agreement analysis was done using Bland Altman plot.Results: Differences between GSMPI and GSBPI for measurement of LVEF at rest in same patient fell within two standard deviation of the mean difference.Thus the apparent overall slight underestimation of LVEF by GSBPI (54.8±25.3) in comparison to GSMPI (56.9±25) was statistically insignificant.Conclusion: There was significant overall agreement between GSMPI and GSBPI for measurement of LVEF in CAD.

Background and Objective: Accurate diagnosis of CAD using noninvasive procedures is of great importance. The aim of the study is to assess diagnostic accuracy of myocardial perfusion imaging and compare it with exercise stress test in order to decipher a more accurate and cost-effective method for CAD detection. Materials and Methods: Of 430 consecutive patients suSPECTed with CAD, 104 performed both MPI (with the method of exercise stress) and ICA (Invasive Coronary Angiography). Luminal stenosis > 70% read by ICA was defined as significant CAD. Considering ICA as the gold standard, we calculated sensitivity, specificity, NPV and PPV for both tests. Besides, the relationship between CAD risk factors and findings of the procedures was also computed, using chi-square and student t-tests. Results: Sensitivity, specificity, PPV and NPV of MPI and exercise test for detection of CAD were: 90. 74%, 92%, 92. 45%, 90. 19%, and 57%, 82%, 77. 5%, 63. 1%, reSPECTively. A significant relationship between diabetes and hyperlipidemia with abnormal perfusion MPI and positive exercise test was found (P<0. 05). Relatively poor agreement was observed between results of MPI and exercise test (kappa statistic = 0. 445). Conclusion: Not only dose MPI benefits from higher diagnostic value for diagnosis of CAD, but it also can be used in patient risk stratification and applying more appropriate therapeutic strategies.

Background: Coronary heart disease (CHD) is a major cause of mortality and morbidity and its management consumes a large proportion of national healthcare budgets. A normal myocardial perfusion scintigraphy (MPS) study is associated with a very low rate of future cardiac events. The objective was to determine the risk of future cardiac events after a normal myocardial perfusion scan (MPS), and whether clinical risk factors alter the risk of future cardiac events after normal MPS in our local population.Materials and Methods: The data were collected from the nuclear medicine database identifying all the reported normal myocardial perfusion scans between January 2008 and December 2011. There were 290 patients identified with normal cardiac nuclear scans in the pre‐specified time frame.103 of these patients were male accounting for 35% of the total population. Average age at the time of examination was 60.6±11.8 years and the highest age group were between 66 and 70 years.Results: There were 2 patients that were admitted with NSTEMI and went on to have diagnostic angiograms. One of those two patients underwent percutaneous coronary intervention with stenting. The other patient had non‐obstructive CAD and was advised for medical management only. These findings are consistent with a 0.7% risk of cardiac events after a negative scan Conclusion: The above findings demonstrate that the risk of major cardiac events after a negative nuclear cardiac scan is low irreSPECTive of the clinical risk factors and is in keeping with the international statistics available.

Introduction- Left ventricular ejection fraction (LVEF) is an important clinical index in diagnosis and treatment of myocardial diseases. There are three major methods for measurement of LVEF: echocardiography, angiography and ECG-Gated SPECT. The first method is economical, safe and rapid. The second one is more accurate, however invasive and the third one lies somewhere in between. Multi-Gated SPECT usually suffers from low reproducibility compared to other methods. This is due to variation in processing factors, mainly reconstruction methods and filtration. Up to now, there is no standard method of processing of cardiac SPECT.Methods- In this study, we attempted to find the optimum processing protocol in which the results are consistent with the angiographic results. Forty patients (referred to our department for myocardial perfusion SPECT) who had angiography within 2 weeks of the test were included in the study. All the patients had a positive history of myocardial infarction. All imaging performed with a single head GE gamma camera SPECT system model DSX using 99mTc- MIBI. Two commonly used reconstruction methods i.e., filtered back projection and ordered subset expectation maximization with different parameters were used and the results compared with that of echocardiography and angiography.Results- In filtered back projection technique, maximum correlation between ECG-Gated SPECT and angiography (r = 0.775) was observed when using Metz filter with psf FWHM=5 and order=5. In OSEM reconstruction technique, the maximum correlation (r = 0.706) between ECG-Gated SPECT and angiography was found using iteration of 2 and subset of 12.Discussion- Angiography is usually assumed the standard method for calculation of LVEF. However, techniques such as ECG-Gated SPECT can be equally accurate if the method of processing is selected optimally. We optimized the method of processing in our department in correlation with the results of angiography.

Introduction: Many patients have only diastolic dysfunction without any abnormality in systolic function. We compared cardiac diastolic parameters obtained by Gated myocardial perfusion SPECT (Gated SPECT) with those evaluated by echocardiography. Methods: Forty-nine patients (aged 37-85 years, 19 males and 30 women) underwent Gated SPECT and echocardiography. Gated SPECT images were obtained with 16 frame/cardiac cycles. We derived the following diastolic indices: peak filling rate (PFR), time to PFR (TTPFR), mean filling rate in the first 1/3 of the diastole (MFR/3) and second filling rate (PFR2) due to left atrial contraction. In echocardiography we obtained the indices of ventricular filling: E wave, A wave, the E/A ratio, and the E wave deceleration time (DT) were considered. The LV isovolumic relaxation time (IVRT) was also determined. Results: There was no significant correlation between echocardiographic findings and diastolic Gated SPECT findings. Using Post-Hoc One-way analysis significant difference was seen only in MFR/3 between diastolic dysfunction groups (P value=0. 02). There was no significant difference in other diastolic Gated SPECT variables in these groups. Conclusion: Diastolic parameters obtained from 16-frame/cardiac cycle Gated SPECT didn’ t correlate with echocardiographic indices.

Fixed myocardial defects in both stress and rest images, could be art factual as a result of soft tissue attenuation. To increase specificity and identify the false positive results, we used Gated technique to evaluate the wall motion and wall thickening as an index to differentiate real ischemic lesions from art factual defects. 93 patients were studied. In 46 patients (48.8%) fixed perfusion defects were identified. Of these patients 10 (21.7%) had definite evidence of previous MI, 6 of whom (60%) showed abnormal Gated SPECT findings. Among 36 patients without history of MI, 11 cases (30%) showed abnormal ventricular function (Probably due to silent MI) and 25 patients (70%) had normal function. The latter group was comprised of 13 females (52%) with fixed perfusion defects seen in the anterior, septal and apical segments of the myocardium. He results of the investigation indicate that using Gated SPECT method with 99mTc-MIBI myocardial perfusion studies increases specificity of the fixed myocardial defects and is highly recommended.

Introduction: Although left ventricular(LV) function parameters measured by Gated myocardial perfusion SPECT (GSPECT) have been validated, experimental data have revealed that the calculated the LV function parameters using GSPECT are affected by patient populations as well as particular acquisition and processing conditions. We tried to determine the normal values of GSPECT in an Iranian population.Methods: We studied 3500 Iranian patients who underwent GSPECT in an outpatient setting. To develop normal limits of LV functional indices using GSPECT, 148 patients with a low (<5%) likelihood of coronary disease and normal tomograms were selected.  No one of 148 patients had known coronary artery disease, typical angina, history of hypertension, diabetes mellitus, and smoking, any abnormality in echocardiography or hyperlipidemia. They were not taking any medication known to affect LV function at least 2 days before the study.  End diastolic volume (EDV), end systolic volume (ESV) and LV ejection fraction (LVEF) were calculated in rest GSPECT using iterative reconstruction and QGS (quantitative Gated SPECT) software. Results: Mean EDV, ESV and LVEF were 53.8±20.2, 14.3±10.8 and 75.0%±9.6% reSPECTively. These data showed a Gaussian distribution, so mean±2SD would show the upper or lower limits of normal for LV functional parameters. There were the marked sex differences in mean LVVs and LVEF measurements. BMI index had not effect on the measurement of the LV functional parameters. We noticed that 85.4% of our subjects had ESV<25 ml while most of them were women (112/123, 91%). Conclusion: From a clinical viewpoint, each institute should use a standard protocol for the specific patient population and for the mode of SPECT acquisition and reconstruction. Normal thresholds using GSPECT, OSEM reconstruction and QGS algorithm in men and women were EDV>130, ESV>55 & LVEF<52% and EDV>77, ESV> 26 and LVEF<62% reSPECTively.

Introduction: Radionuclide scanning of the heart has incremental value in diagnosis and risk stratification of coronary artery disease. Gated myocardial perfusion SPECT is a new method and the state of the art in coronary artery disease detection. This study was done to evaluate estimation of LV volume, wall motion diameters and ejection fraction by Gated myocardial perfusion scan and make a comparison with trans thoracic echocardiography.Material and Methods: In this cross-sectional descriptive study during Sep 2001-Dec 2002, 68 patients suSPECTed of IHD who were referred to nuclear Medicine Department of Imam Reza Hospital in Mashhad University of Medical Sciences were under taken Gated myocardial perfusion SPECT, and then referred to echocardiography unit for trans thoracic echocardiography. LV volume, ejection fraction, regional wall motion in different views of 2D-echo was recorded and the results were compared by descriptive statistics.Results: This study was performed on 68 patients. The mean age of patients was 52.8 (min: 38, Max: 75). 54% of patients were male and 46% were female. Mean end systolic volumes of LV was 32.4ml (sd: 37.1) estimated by echocardiography and 68.3ml (sd: 52.2) stimated by radionuclide scan (pv: 0.00). Mean end diastolic volume of LV was l29.6ml (sd: 45.8) in echocardiography and l43.7ml (sd: 46.23) in radionuclide scanning (pv: 0.00). Mean ejection fraction value of LV was 54.6 (sd: 12.44) estimated by echocardiography and 54 (sd: 12.94) by radionuclide scan (pv: 0.00).Conclusions: Left ventricular end systolic and diastolic volumes and ejection fraction, obtained by Gated myocardial perfusion scan and echocardiography, had significant statistic correlations and estimation of LV wall motions and ejection fraction by Gated SPECT was as echocardiography.

Background & Aims: Nowadays, imaging of the blood supply of the heart muscle by single photon emission computed tomography (SPECT: Single Photon Emission Computed Tomography) due to its non-invasive nature and providing information with physiological value and low cost compared to the valuable angiography method. It is highly diagnostic. But these images undergo changes and artifacts under the influence of factors, the result of which is the reduction of the diagnostic accuracy of the images and false positive cases. During the detection process, several physical effects such as attenuation, scattering, and collimator response function affect the frequency of emitted photons,this leads to the destruction of the contrast and as a result of reducing the quantitative and qualitative accuracy of the images. Attenuation, as the most destructive factor of SPECT images, reduces the quality of SPECT images of heart blood supply and reduces the sensitivity of tests related to the diagnosis of coronary artery diseases, and for non-uniform environments, especially in nuclear imaging of chest areas. And the heart is necessary to produce a map of patient attenuation coefficients. The existence of scattered photons is also one of the main factors of error in quantization,the detection of scattered events affects the contrast of the lesions and causes the lack of image resolution and signal-to-noise ratio. Therefore, to correct the attenuation and scattering of the rays in the heart images quantitatively and qualitatively, patterns are needed in SPECT systems. Due to the importance of the topic, various research groups around the world have presented their research and results on correcting the effect of scattering of rays and also correcting the effect of weakening the rays. If there was no limitation of energy resolution, it was easily possible to identify the scattered rays and prevent them from being recorded in the image. Because we know that scattered rays lose energy. Because gamma rays are single energy and their energy amount is completely known. Therefore, each photon with less energy will represent scattered rays, but due to the limited energy resolution of the gamma camera, a range is usually considered on the sides of the main energy, which is called the energy window. It is assumed that the photons recorded in this energy range are primary photons, but in fact, many photons scattered in the body are also recorded in this window. These scattered rays do not carry correct spatial information and lead to a decrease in image resolution and contrast and quantization errors in the image. In nuclear medicine, instead of researching and examining the patient or processing the image of the patient, simulated images can be examined. Simulators can provide information about each of the image destruction factors. The purpose of this research is to propose a new method for scattering correction, in this research, a combination of Monte Carlo and modeling is used for the rapid production of scattered views, and in the proposed method, the two-matrix method is used, this method At the stage of generating mathematical views, dispersion is added and this problem leads to the removal of scattered rays. As a result, an image is reconstructed that is free from the effects of attenuation and non-ideal dispersion and leads to an increase in contrast and improvement of power. Detecting waste, increasing the signal-to-noise ratio, and increasing the accuracy of quantification. Methods: In this study, the effect of applying attenuation and dispersion correction using two energy windows (DEW) and three energy windows (TEW) methods in cardiac aSPECT imaging was investiGated and evaluated, and to simulate cardiac aSPECT imaging, a special code similar to SAR Monte Carlo GATE was used as the SPECT imaging system and XCAT digital phantom with activity distribution and realistic attenuation map was used to model the human trunk. Results: Comparison of image contrast improvement in different modes of attenuation and dispersion correction shows that the highest image contrast is obtained from the (TEW1+AC) method with an average increase of 25% and MSE in different modes of attenuation correction. And the dispersion compared to the reference image was reduced from 51. 5% to 54. 5%. Compared to the reference image, MSE decreased from 1. 4 in Un_Cor to 1. 15, 1. 13, 1. 12, and 1. 14 in AC+TEW1, AC+DEW, AC, and AC+TEW2, reSPECTively, and the signal-to-noise ratio (SNR) increased up to 71% in all methods of applying dispersion correction along with attenuation correction compared to applying attenuation correction (AC). Conclusion: In this study, the effect of attenuation and dispersion correction in 5 non-correction modes, with attenuation correction, attenuation, and dispersion correction using two-window and three-window methods with triangular approximation and three-window with trapezoidal approximation on We evaluated XCAT phantom simulated images and heart muscle perfusion images by SPECT method and 4 different parameters were used to compare and evaluate the images, including profile, contrast, mean squared error (MSE) and signal to noise. According to the results of the quantification of reconstructed images, it is possible to apply dispersion correction along with attenuation correction.