Fixed Perfusion Defects Research Articles

Radionuclide Imaging Findings in Iatrogenic Stress in Cases with Reduced Left Ventricular Ejection Fraction

Objective: This study aims to contribute to the existing literature by assisting in the selection of stress protocols for patients with reduced left ventricular ejection fraction (LVEF). We also aim to provide insights into patient follow-up based on changes in post-stress LVEF determined by echocardiography. Methods: Our retrospective study encompassed 487 patients initially diagnosed with coronary artery disease. Left ventricular function was assessed using echocardiography and myocardial perfusion scintigraphy. Among them, 250 patients with LVEF values within normal limits constituted Group-1, while 237 patients with LVEF values below 50% formed Group-2. Exercise stress testing was performed using a treadmill according to the Bruce protocol. For vasodilator stress testing, intravenous adenosine infusion at a rate of 140 μg/kg/min was administered for 6 minutes. Tc-99m-sestamibi was intravenously administered (8-12 mCi) for stress imaging and (24-36 mCi) for rest imaging. Results: The median age of all patients in the study was 64 (52-79) years, with 283 (58.1%) being male. Myocardial perfusion, assessed by myocardial perfusion scintigraphy, revealed a fixed perfusion defect in all patients. Reversible perfusion defects were observed in 172 (35.3%) patients. Among patients with reduced echo-LVEF values, those who underwent exercise stress testing showed significantly lower post-stress EF values compared to those who underwent vasodilator stress testing (35 (25-42) vs. 36 (30-47), p: 0.0005). Post-stress LVEF was notably lower in patients with reversible perfusion defects, indicating a higher rate of LVEF decrease due to stress (p: 0.0005). Conclusion: Left ventricular ejection fraction (LVEF) serves as a valuable metric for assessing left ventricular function. The findings from this study support its utility in guiding the selection of a suitable stress protocol and monitoring patients during iatrogenic cardiac stress applications.

Standardized Radiomics Analysis of Clinical Myocardial Perfusion Stress SPECT Images to Identify Coronary Artery Calcification.

Myocardial perfusion (MP) stress single-photon emission computed tomography (SPECT) is an established diagnostic test for patients suspected of coronary artery disease (CAD). Meanwhile, coronary artery calcification (CAC) scoring obtained from diagnostic CT is a highly sensitive test, offering incremental diagnostic information in identifying patients with significant CAD yet normal MP stress SPECT (MPSS) scans. However, after decades of wide utilization of MPSS, CAC is not commonly reimbursed (e.g. by the CMS), nor widely deployed in community settings. We studied the potential of complementary information deduced from the radiomics analysis of normal MPSS scans in predicting the CAC score. We collected data from 428 patients with normal (non-ischemic) MPSS (99mTc-sestamibi; consensus reading). A nuclear medicine physician verified iteratively reconstructed images (attenuation-corrected) to be free from fixed perfusion defects and artifactual attenuation. Three-dimensional images were automatically segmented into four regions of interest (ROIs), including myocardium and three vascular segments (left anterior descending [LAD]-left circumference [LCX]-right coronary artery [RCA]). We used our software package, standardized environment for radiomics analysis (SERA), to extract 487 radiomic features in compliance with the image biomarker standardization initiative (IBSI). Isotropic cubic voxels were discretized using fixed bin-number discretization (eight schemes). We first performed blind-to-outcome feature selection focusing on a priori usefulness, dynamic range, and redundancy of features. Subsequently, we performed univariate and multivariate machine learning analyses to predict CAC scores from i) selected radiomic features, ii) 10 clinical features, and iii) combined radiomics + clinical features. Univariate analysis invoked Spearman correlation with Benjamini-Hotchberg false-discovery correction. The multivariate analysis incorporated stepwise linear regression, where we randomly selected a 15% test set and divided the other 85% of data into 70% training and 30% validation sets. Training started from a constant (intercept) model, iteratively adding/removing features (stepwise regression), invoking the Akaike information criterion (AIC) to discourage overfitting. Validation was run similarly, except that the training output model was used as the initial model. We randomized training/validation sets 20 times, selecting the best model using log-likelihood for evaluation in the test set. Assessment in the test set was performed thoroughly by running the entire operation 50 times, subsequently employing Fisher's method to verify the significance of independent tests. Unsupervised feature selection significantly reduced 8×487 features to 56. In univariate analysis, no feature survived the false-discovery rate (FDR) to directly correlate with CAC scores. Applying Fisher's method to the multivariate regression results demonstrated combining radiomics with the clinical features to enhance the significance of the prediction model across all cardiac segments. Conclusions: Our standardized and statistically robust multivariate analysis demonstrated significant prediction of the CAC score for all cardiac segments when combining MPSS radiomic features with clinical features, suggesting radiomics analysis can add diagnostic or prognostic value to standard MPSS for wide clinical usage.

Non-Invasive Assessment of Myocardial Perfusion Abnormality in Type 2 Diabetic Patients Without Symptoms of Coronary Artery Disease by SPECT-MPI

Introduction: Coronary artery disease (CAD) is the most common chronic macrovascular complication of diabetes mellitus. Diabetic patients have a high incidence of silent ischemia and MI due to autonomic neuropathy. SPECT imaging is a well-established, non-invasive procedure that offers perfusion and functional information for diagnosis and risk stratification, facilitating the early detection of CAD. Objective: To detect myocardial perfusion abnormality by SPECT-MPI in type 2 diabetic patients without symptoms of CAD. Methods: A total of eighteen diabetic patients with no history of typical CAD, with or without risk factors, underwent gated SPECT-MPI using 99mTc-sestaMIBI. A single-day stress–rest protocol with adenosine was done in each patient. Result: Six out of eighteen patients (33.3%) showed abnormal scans suggestive of myocardial ischemia or infarction. Four of these patients had reversible perfusion defects, one had a fixed perfusion defect, and one had a mixed defect. Among these patients, single vessel territory was involved in three patients, and three patients had involvement in double vessel territories. Regarding the summed stress score (SSS) value, most of the patients (four) had mild risk, whereas moderate and severe risk of a future cardiac event were observed in one patient each. In addition, two patients had left ventricular dysfunction (EF< 45%). Five patients with normal MPI and two patients with abnormal myocardial perfusion scans had high transient ischemic dilatation (TID). Risk factors such as male sex, hypertension, hyperlipidemia, obesity, and family history of CAD were not significantly correlated with abnormal scans. But abnormal scans were significantly related to a longer duration of diabetes (P = 0.038). Conclusion: This study showed that despite being asymptomatic, a considerable portion of diabetic patients had perfusion abnormalities, not just ischemia but also infarctions. Moreover, some of these patients are at high risk for future cardiac events as assessed by SSS, TID, and LVEF. Bangladesh J. Nuclear Med. 25(2): 110-116, 2022

"Ebstein's Anomaly" a Potential Cause of Misinterpretation on Myocardial Perfusion Imaging.

Ebstein's anomaly is a rare congenital heart disease. We present the case of a 47-year-old woman with history of Ebstein's anomaly who was referred to nuclear medicine department for a myocardial perfusion single-photon emission computed tomography (SPECT) imaging during pre-anesthetic check-up. Myocardial SPECT perfusion images with (99mTc)-Sestamibi demonstrated medium sizes fixed perfusion defect in the mid and proximal infero-septal wall adjacent inferior wall. This is a cause of potential misinterpretation on myocardial SPECT perfusion imaging as this perfusion defect was due to fibrosis rather than scarred myocardium.

A unique pitfall of myocardial perfusion imaging in transthyretin amyloid cardiomyopathy

Myocardial Perfusion Imaging (MPI) is a non-invasive modality with proven diagnostic and prognostic utility in coronary artery disease. We present a case of Transthyretin Amyloid Cardiomyopathy (ATTR-CM) where MPI findings were vastly different from Transthoracic Echocardiogram (TTE) and Cardiac Magnetic Resonance Imaging (CMR). A 78-year-old gentleman presented with atypical chest pain to rule out ischemic heart disease. He underwent MPI scan, revealing a medium-sized fixed perfusion defect of moderate intensity in the inferior segments.

Myocardial perfusion imaging failed to improve patient risk classification compared with the revised cardiac risk index for early cardiac complications after major non-cardiac surgery.

Myocardial perfusion imaging (MPI) is frequently used for cardiac risk assessment before major non-cardiac surgery, but its ability to improve patient risk classification beyond simple clinical assessment is unknown. To explore the prognostic utility of MPI above a simple clinical risk calculator, the revised cardiac risk index (RCRI). A retrospective cohort study of at-risk patients who underwent MPI before major non-cardiac surgery in a tertiary hospital was conducted. Major adverse cardiac events (MACE) was defined as any myocardial infarction, acute pulmonary oedema, ventricular arrhythmia or cardiac death within 30 days of surgery. We analysed the predictive value of MPI for MACE using multivariable logistic regression and categorical net reclassification index. MACE occurred in 47 (7.4%) cases from 635 surgical procedures in 629 patients. MPI-identified medium or large-sized reversible perfusion defects (P = 0.02; odds ratio 2.9; 95% confidence interval 1.1-7.1) and RCRI score two or more (P = 0.03; odds ratio 2.3; 95% confidence interval 1.1-4.8) were significantly associated with MACE after adjusting for age, coronary revascularisation, surgical priority, need for general anaesthesia, left ventricular ejection fraction (LVEF) and fixed perfusion defects. MPI risk factors (LVEF, reversible perfusion and fixed perfusion defects) did not improve risk classification above baseline risk factors (age, RCRI and surgical priority). MPI risk factors are weak predictors for early cardiac complications after major non-cardiac surgery and failed to improve patient risk classification beyond essential assessment using age, RCRI and surgical priority. Clinicians should consider alternative risk assessment strategies because of MPI's poor prognostic utility and its associated time and financial costs.

Incremental prognostic value of spect over CCTA

BackgroundCoronary computed tomographic angiography (CCTA) and Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) provide comprehensive anatomic and functional assessment of the coronary arteries useful in the diagnosis and prognosis of patients with coronary artery disease (CAD). We aimed to assess the incremental prognostic role of SPECT physiologic assessment to CCTA in patients with suspected CAD. MethodsConsecutive patients with suspected CAD undergoing clinically indicated CCTA within 180 days of undergoing SPECT were included. Patients were followed for major adverse cardiovascular events (MACE, inclusive of all-cause death, non-fatal myocardial infarction, and percutaneous coronary intervention or coronary artery bypass grafting 90-days after imaging test.) ResultsThe cohort consisted of 956 patients (mean age 61.1 ± 14.2 years, 54% men, 89% hypertension, 81% diabetes, 84% dyslipidemia). Obstructive stenosis was found in 14% of patients, while scar (fixed perfusion defect), ischemia and left ventricular ejection fraction <40% were found in 17, 14 and 9% of patients, respectively. In nested multivariable cox regression models, perfusion and left ventricular function when added to a model with CCTA obstructive stenosis significantly improved model risk prediction (Harrell's C = 0.73, p = 0.037) and risk reclassification on a continuous scale (P < 0.001). ConclusionWe have shown that a combined assessment of perfusion burden and left ventricular function added incremental value over and above a CCTA based anatomic assessment in patients with suspected CAD.

Complementary role of computed tomography angiography with fixed perfusion defects on SPECT myocardial perfusion imaging

PurposeWe present this case series exploring the complementary role of coronary computed tomography angiography (CCTA) to SPECT myocardial perfusion imaging (MPI) in the detection of myocardial necrosis.MethodsA cardiac hybrid imaging database search identified 144 patients with a previous history of ST-segment elevation myocardial infarction treated with coronary revascularization. CCTA and MPI scans were evaluated to determine whether CCTA had an added value to MPI in detecting myocardial necrosis.ResultsFive patients with patent stents and/or bypass grafts and both fixed perfusion defects on MPI and sub-endocardial hypo-perfusion on CCTA were identified. The extent and location of the perfusion defects were closely correlated between the CCTA and SPECT MPI images.ConclusionIn this series, CCTA and SPECT MPI were found to play a complementary role in the assessment of fixed perfusion defect, with CCTA adding specificity to the diagnosis of myocardial necrosis.

Myocardial Perfusion Imaging Failed to Improve Patient Risk Classification Compared to the Revised Cardiac Risk Index for Early Cardiac Complications After Major Non-Cardiac Surgery

Cardiac evaluation is desirable before major non-cardiac surgery with myocardial perfusion imaging (MPI) frequently utilised for risk assessment. However, the prognostic utility of MPI above a simple clinical risk calculator, the Revised Cardiac Risk Index (RCRI), is unknown. We conducted a retrospective cohort study of patients who underwent MPI before major non-cardiac surgery, incorporating 635 surgical procedures in 629 patients over six years. Major adverse cardiac events (MACE) within 30 days of surgery, including any myocardial infarction, acute pulmonary oedema, ventricular arrhythmia, or cardiac death, occurred in 47 (7.4%) cases. We analysed predictive value of MPI for MACE using multivariable logistic regression and categorical net reclassification index. MPI-identified medium or large-sized reversible perfusion defects (p=0.02, odds ratio 2.9 [95% CI 1.1-7.1]) and RCRI score two or more (p=0.03, odds ratio 2.3 [(95% CI 1.1-4.8]) were significantly associated with MACE after adjusting for age, coronary revascularisation, surgical acuity, need for general anaesthesia, left ventricular ejection fraction (LVEF) and fixed perfusion defects. Net reclassification index comparing models with and without MPI risk factors (LVEF, reversible perfusion and fixed perfusion defects) did not significantly improve risk classification. MPI risk factors are weak predictors for early cardiac complications after major non-cardiac surgery and failed to improve patient risk classification beyond a simple risk assessment using age, RCRI and surgical priority. Clinicians should consider alternative risk assessment strategies because of MPI's poor prognostic utility and its associated time and financial costs.

Prognostic implication of myocardial perfusion and contractile reserve in end-stage renal disease: A direct comparison of myocardial perfusion scintigraphy and dobutamine stress echocardiography

BackgroundWe aimed to compare the prognostic value of myocardial perfusion scintigraphy (MPS) and dobutamine stress echocardiography (DSE) in patients with end-stage renal disease (ESRD) without known coronary artery disease. MethodsTwo-hundred twenty-nine ESRD patients who applied for kidney transplantation at our centre were prospectively evaluated by MPS and DSE. The primary endpoint was a composite of myocardial infarction (MI) or all-cause mortality. The secondary endpoint included MI or coronary revascularization (CR) not triggered by MPS or DSE at baseline. ResultsMPS detected reversible ischemia in 31 patients (13.5%) and fixed perfusion defects in 13 (5.7%) patients. DSE discovered stress-induced wall motion abnormalities (WMAs) in 28 (12.2%) and at rest in 18 (7.9%) patients. MPS and DSE results agreed in 85.6% regarding reversible defects (κ = 0.358; P < .001) and in 90.8% regarding fixed defects (κ = 0.275; P < .001). Coronary angiography detected relevant stenosis > 50% in only 15 of 38 patients (39.5%) with pathological findings in MPS and/or DSE. At a median follow-up of 8 years and 10 months, the primary endpoint occurred in 70 patients (30.6%) and the secondary endpoint in 24 patients (10.5%). The adjusted Cox hazard ratios (HRs) for the primary endpoint were 1.77 (95% CI 1.02-3.08; P = .043) for perfusion defects in MPS and 1.36 (95% CI 0.78-2.37; P = ns) for WMA in DSE. The secondary endpoint was significantly correlated with the findings of both modalities, MPS (HR 3.21; 95% CI 1.35-7.61; P = .008) and DSE (HR 2.67; 95% CI 1.15-6.20; P = .022). ConclusionPerfusion defects in MPS are a stronger determinant of all-cause mortality, MI and the need for future CR compared with WMAs in DSE. Given the complementary functional information provided by MPS vs DSE, results are sometimes contradictory, which may indicate differences in the underlying pathophysiology.

Application value between dynamic electrocardiogram and MSCT myocardial perfusion imaging in the diagnosis of myocardial ischemia in coronary heart disease.

Dynamic electrocardiogram and multi-spiral computed tomography (MSCT) myocardial perfusion imaging are commonly used in clinical examination methods, which can provide important reference for the diagnosis of myocardial ischemia in coronary heart disease. To analyze and compare the application value of dynamic electrocardiogram and MSCT myocardial perfusion imaging in the diagnosis of myocardial ischemia in coronary heart disease. The clinical data of 79 patients diagnosed with coronary heart disease admitted in our hospital from October 2017 to October 2019 were retrospectively collected. Exercise load/rest myocardial perfusion imaging (MPI) confirmed the presence of myocardial ischemia, and the patients were all examined by dynamic electrocardiogram and MSCT. The diagnosis of exercise load/resting MPI was used as a benchmark to compare the sensitivity, specificity, and accuracy of the different tests in the diagnosis of myocardial ischemia in coronary heart disease. As confirmed by the exercise load/rest MPI, the 79 included patients had myocardial ischemia. Fifty-five cases of myocardial ischemia were detected by dynamic electrocardiogram, of which 33 cases showed horizontal depression of the ST segment. Also, 15 cases exhibited downward oblique depression, and seven cases showed upward oblique depression. MSCT examination showed that 78 patients had myocardial ischemia, of which 74 showed abnormal myocardial perfusion when contracted. Of these patients, 47 showed reversible perfusion filling, 20 exhibited partially reversible perfusion filling, and seven showed fixed perfusion defects. The sensitivity, specificity, and accuracy of dynamic electrocardiogram in the diagnosis of myocardial ischemia in coronary heart disease were 60.76%, 72.15%, 69.62%, respectively, while those of MSCT were 91.14%, 75.94%, and 86.07%, respectively. The sensitivity and accuracy of MSCT examination were significantly higher than those of dynamic electrocardiogram examination (P<0.05), and the specificity was slightly higher than that of dynamic electrocardiogram examination, but this difference was not statistically significant (P>0.05). Compared to dynamic electrocardiogram examination, MSCT myocardial perfusion imaging has superior sensitivity and accuracy in the diagnosis of myocardial ischemia in coronary heart disease, and can provide a reference for clinical diagnosis and treatment.

Prognostic Significance of Myocardial Ischemia Detected by Single-Photon Emission Computed Tomography in Children with Hypertrophic Cardiomyopathy

Myocardial ischemia caused by microvascular dysfunction is an important pathophysiologic component of hypertrophic cardiomyopathy (HCM), promoting myocardial fibrosis, adverse left ventricular remodeling, and impacting on clinical course and outcome in HCM patients. The aim of study was to assess the prevalence and clinical significance of myocardial ischemia in children with HCM using 99mTc-MIBI single-photon emission computed tomography (SPECT). Ninety-one children with HCM, median age 13.6 years, underwent SPECT evaluation from 2006 to 2017. Imaging was performed at rest and after maximal exercise. Myocardial perfusion defects were identified in 70 children (76.9%; group I), median age 13.8 years. Fixed perfusion defects were evident in 22 of them, while reversible at rest in 48. In 21 children (23.1%; group II), median age 11 years, myocardial perfusion defects were not detected. Patient demographics, echocardiography, resting electrocardiogram (ECG), 24-h Holter ECG, myocardial fibrosis in cardiovascular magnetic resonance imaging, and cardiovascular events were analyzed and compared between the groups. During follow-up at a median of 8.3 years in children with myocardial ischemia, clinical endpoints occurred more often (47 vs. 5; p = 0.02) and more patients reached a clinical endpoint (28 [40%] vs. 3 [14.3%]; p = 0.036). In children with myocardial ischemia, myocardial fibrosis was observed with greater frequency. Myocardial perfusion defects may reflect an ischemic process which (1) affects the clinical manifestations and (2) is an important predictor of adverse clinical events and risk of death in children with HCM. Myocardial ischemia in HCM patients frequently correlates with myocardial fibrosis.

Fixed myocardial perfusion defects on SPECT are not associated with focal myocardial fibrosis on CMR in adult patients with systemic right ventricle

Abstract Funding Acknowledgements Type of funding sources: None. Background Myocardial fibrosis is a known prognostic factor in patients with systemic right ventricle (SRV). In these patients fixed myocardial perfusion defects are a common finding and are thought to represent areas of myocardial infarction and fibrosis. However, no study has yet correlated myocardial perfusion imaging findings with cardiac magnetic resonance (CMR) imaging, which is the imaging gold standard for detecting myocardial fibrosis. Purpose Our aim was to evaluate whether fixed myocardial perfusion defects in adult patients with SRV represent myocardial fibrosis. Methods Patients with SRV followed at our outpatient clinic for congenital heart disease were prospectively included. Myocardial perfusion was evaluated with a two-day stress/rest single-photon emission computed tomography (SPECT) protocol, focal myocardial fibrosis with late gadolinium enhancement (LGE) and diffuse myocardial fibrosis with T1 mapping by CMR. The 12-segment model of the right ventricle was used to report segments with myocardial perfusion defects and fibrosis (Figure 1). Results Fifteen patients with SRV (12 patients with transposition of the great arteries following atrial switch procedure and 3 patients with congenitally corrected transposition of the great arteries; 4 (26.7%) females; mean age 34.6 ± 10.0 years) were included. Myocardial perfusion defects were present in 14 patients (93%), with predominate fixed perfusion defects (73%) and less common reversible perfusion defects (27%). Fixed myocardial perfusion defects were most frequent in anterior RV segments (figure 1), with multiple segments affected in 11 patients (median number of affected segments – 2 segments). CMR was possible in 11 (73%) patients, others had a permanent pacemaker. LGE indicating focal myocardial fibrosis was detected in only 1 (9%) patient, while increased T1 values indicating diffuse myocardial fibrosis were present in 7 (64%) patients. There was no matching between areas of fixed myocardial perfusion defects and focal myocardial fibrosis in individual patients. Conclusions In our study, fixed myocardial perfusion defects detected on SPECT in patients with SRV did not represent areas of focal myocardial fibrosis on CMR. Other causes than scar may explain the frequently reported fixed perfusion defects, such as SRV anatomy with anterior position of the outflow tract and aorta, SRV morphology with variable degree of wall thickness and hypertrophy that influences tracer accumulation and image quality, or difficulties due to complex image acquisition and interpretation. To improve the diagnostic accuracy, the use of fused imaging modalities (SPECT-CT or PET-CT) is recommended in patients with SRV. Figure 1. Bull`s eye 12-segment plots of the right ventricle (RV) representing the number of segments with fixed myocardial perfusion defects detected by SPECT (1A) and LGE by CMR (1B) in patients with SRV. ANT – anterior, FW – free wall, INF – inferior, SEP – septal wall of RV. Abstract Figure.

Direct correlation between ischemic burden induced by dipyridamole and stress peak filling rate: a gated perfusion single-photon emission computed tomography study.

The aim of the present study was to assess the effects of dipyridamole on stress and rest peak filling rate in consecutive patients who showed perfusion and, or function abnormalities at Gated-SPECT. Were enrolled 96 patients (73 males (76%); mean age 71.7 ± 9.57). Forty patients (41.7%) had an history of myocardial infarction and fifty-seven (59.4%) of previous cardiac revascularization. All patients underwent a 2-day 99mTc-SestaMIBI gated perfusion SPECT protocol. Twenty-nine (30.2%) patients showed fixed perfusion defects, 54 (56.2%) showed partially or completely reversible ones, while 13 (13.5%) showed normal perfusion but reduced LVEF. SSS was significantly higher than SRS (9.55 ± 9.29 vs. 7.10 ± 8.48; P = 0.0001). Stress peak filling rate was not significantly higher than rest peak filling rate (1.73 EDV/s ± 0.69 EDV/s vs. 1.67 EDV/s ± 0.56 EDV/s; P = 0.62). At a multivariate regression analysis, only stress peak filling rate, as independent variable, was directly correlated with myocardial ischemia (SDS) (P = 0.018). We divided patients according to SDS in those with mild (SDS < 5) and severe (SDS ≥ 5) ischemia. Stress peak filling rate was the only parameter significantly different between groups. Stress PFR showed a better correlation with the degree of ischemia compared to the remaining perfusion and functional parameters. The direct correlation between SDS and stress PFR leads us to speculate that dipyridamole could improve diastolic function in ischemic patients.

Role of Gated SPECT MPI in Follow-up of Patients afterCoronary Revascularization

Objective: Gated SPECT myocardial perfusion imaging (GSMPI) is a preferred modality for non invasive assessment following coronary revascularization (CR) of both symptomatic and asymptomatic patients. This study was conducted to observe the impact of GSMPI results on further management of patients who after CR had underwent GSMPI at National Institute of Nuclear Medicine and Allied Sciences (NINMAS).&#x0D; Patients and methods: Record files of GSMPI of all patients who underwent GSMPI over a period of 31 months from June 2011 to December 2013 at NINMAS for assessment of perfusion after CR were selected from the Nuclear Cardiology Divisional archive of patient studies in order to retrieve their clinical and demographic data including the contact numbers. The results of GSMPI scan were categorized as normal scan (NS) and perfusion defect (PD) which included reversible and/or fixed PD. All the contact numbers were called up by a nuclear medicine physician who conducted a semi-structured telephonic interview either with the patients or with a concerned family member. Management strategies adopted after GSMPI were categorized as conservative (CM) and interventional (IM).Cramer’s V (φc) test were done to find strength of relation among patients’ symptoms, scan findings and management strategies.&#x0D; Results: Follow up data of 55 patients (54M, 1F) among 68 (66M, 2F) were available who underwent MPI for the purpose of post CR assessment. MPI was performed in between six months to 13 years after CR (mean 43.8 ± 48.2 months). Categorically 33 patients had percutaneous transluminal coronary angioplasty (PTCA) with stent, 16 patients had coronary artery by-pass grafting (CABG) and 6 patients had both CABG &amp; PTCA. There were 38PD (27symptomatic) and 17NS(12 symptomatic).Since all patients (n=12) who had fixed PD were symptomatic, a strong relation was found between being symptomatic and fixed perfusion defect (φc&gt; 0.3). Symptoms were found to be weakly related with reversible PD i.e. ischemia (φc&lt; 0.2). Management strategies were conservative in 44 (30 symptomatic and 28 PD) and interventional in 11 (nine symptomatic and 10 PD). Management strategies were found to be weakly related with symptoms (φc&lt; 0.2) but moderately related with perfusion status (φc = 0.24).&#x0D; Conclusions: While symptoms were observed to be poorly related with perfusion status following CR, GSMPI guided to choose further interventional management strategies with rationality in lower proportion of patients.&#x0D; Bangladesh J. Nuclear Med. 22(1): 30-35, Jan 2019

Myocardial Perfusion Imaging in the Evaluation of Outcome of Coronary Intervention in Coronary Artery Disease Patients

Background: Coronary artery disease (CAD) is an important medical and public health issue because it is one of the leading causes of death and disability throughout the world and is rapidly emerging as a major cause of mortality in developing countries including Bangladesh. SPECT-MPI is a cost- effective and non invasive means of identifying ischemic and viable myocardium along with its vascular distribution. This study is aimed to evaluate prospectively the ability of MPI to predict the outcome of Coronary Intervention in CAD patients of Bangladesh who are referred to National Institute of Nuclear Medicine &amp; Allied Sciences (NINMAS) for performing MPI.&#x0D; Patients and Methods: This prospective longitudinal and observational type of study was carried out in National Institute of Nuclear Medicine &amp; Allied Sciences (NINMAS) located at Bangabandhu Sheikh Mujib Medical University (BSMMU) campus, from July 2017 to June 2018with 12 CAD patients who were referred here. Gated SPECT MPI was performed on the selected patients before any coronary intervention to predict myocardial viability &amp; probable outcome of intervention. A follow up MPI of the same patients was performed after minimum 3 to 4 months of revascularization procedure to determine the outcome of intervention and to detect in stent restenosis or new onset ischemia if present which can be prevented by additional revascularization procedure. Finally pre and post intervention MPI results were analyzed by standard statistical analysis by using the Statistical Package for Social Sciences version 20.0 for Windows (SPSS Inc., Chicago, Illinois, USA). P values &lt;0.05 was considered as statistically significant.&#x0D; Results: The sensitivity of MPI for the initial evaluation and risk stratification by diagnosing perfusion defect in the enrolled 12 CAD patients have been found to be 90%,77.8% and 81.8% in case of LAD, LCX and RCA territories respectively. Whereas the specificity and positive predictive value have been found 100% for LAD and RCA territories. About 16.67% patients were found to have restenosis in this study diagnosed by early post-intervention MPI. It was observed that majority of the patients had perfusion defect in LAD territory. 3(25.0%) patients had fixed defect, 5(41.7%) patients had partial reversible defect and 4(33.3%) patients had complete reversible defect in pre intervention MPI. In post intervention MPI, 4(33.3%) patients had partially reversible perfusion defect, 2(16.7%) patients had fixed perfusion defect, 1(3.3%) patient was found with completely reversible perfusion defect and 5(41.7%) patients had normal MPI findings. The result was found statistically significant (P value &lt;0.05) in case of partially reversible perfusion defect and normal MPI findings when before and after intervention MPI results were compared. The difference of mean percentage of involved myocardium by fixed defect between pre and post intervention MPI was found statistically significant (P&lt;0.05) in case of LAD territory and total LV myocardium involvement. 33.3% patients were in high risk before undergoing intervention, whereas it was found to be 25% after intervention which was calculated on the basis of their pre and post intervention SSS(Summed Stress Score) result.&#x0D; Conclusion: The results of this study have indicated that SPECT MPI provides significant independent information concerning the outcome of coronary intervention in CAD patients. Furthermore, early SPECT MPI after intervention successfully identified significant improvement of myocardial viability after revascularization in patients having complete or reversible perfusion defects found in pre intervention MPI along with identifying those having restenosis. It could also depict the reduction of percentage of myocardial fixed defects within 3-4 months after intervention which is also a positive outcome of coronary revascularization.&#x0D; Bangladesh J. Nuclear Med. 22(1): 23-29, Jan 2019

P6148Visually assessed coronary and cardiac calcium outperforms perfusion data during scintigraphy in the prediction of adverse outcomes

Abstract Background The presence and amount of calcium in the coronary arteries, but also in the heart valves and aorta, has been clearly associated with cardiovascular and all-cause mortality and this information might be prognostically useful during SPECT-CT examinations, where CT images are co-registered for attenuation correction of myocardial perfusion, but then discarded. Objectives This study sought to determine whether the assessment of calcifications of the coronary arteries, cardiac valves and thoracic aorta in the computed tomography images co-registered for attenuation correction during stress-scintigraphy (SPECT-CT) is associated with long-term mortality and cardiac events on top of other available data. Methods Baseline data were collected prospectively on 353 consecutive patients, referred for suspected coronary artery disease (CAD) with no previously known CAD who underwent stress SPECT-CT between Sept 2010 and Oct 2012. Retrospective analysis was performed on follow-up data for outcomes. Results Patients (mean age 72 years. 58% males) had a mean follow-up of 6.4 years, during which 48 died (15 from cardiovascular causes) and 10 had a non-fatal myocardial infarction (MI). Reversible myocardial perfusion defects were detected in 55 patients (15.6%), 39 of whom (11%) had more than mild defects. The presence of an overall visual calcium score &gt;1 in the attenuation correction images was the most strong univariable (hazard ratio 8.99, p&lt;0.0001) and multivariable (hazard ratio 4.76, p&lt;0.0001) predictor of all-cause death or non-fatal MI on top of age, gender, irreversible myocardial perfusion defects and revascularization after the test. Multivariable models Clinical + SPECT + Overall Calcium Ischemic Cardiac Events HR CI (95%) p-value χ2 Age 1.058 1.0234 to 1.093 0.0008 Male gender 1.63 0.88 to 3.024 0.1183 Fixed perfusion defect 3.924 1.63 to 9.426 0.0022 Overall Calcium &gt;1 4.765 2.2 to 10.32 &lt;0.0001 71.69 Kaplan-Meier Conclusions Visual assessment of coronary or overall coronary, cardiac and aortic calcium in the CT images used for attenuation correction during SPECT-CT is feasible, reproducible and strongly associated with hard cardiac events and all-cause death, beyond clinical variables and myocardial perfusion data. This incredibly easy visual calcium assessment does not require additional costs or radiation and may heavily impact on better risk-assessment of patients with suspected CAD undergoing SPECT-CT.

Gated single-photon emission computed tomography myocardial perfusion imaging is superior to computed tomography attenuation correction in discriminating myocardial infarction from attenuation artifacts in men and right coronary artery disease.

In single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) studies, attenuation artifacts frequently cause false positives, which can be partially overcome by computed tomography attenuation correction (CT-AC) or gated acquisition [gated myocardial perfusion imaging (GMPI)]. The purpose of this study is to evaluate their relative diagnostic performances for coronary artery disease (CAD). We enrolled 181 patients who underwent gated SPECT with CT-AC in this study. Two observers who were blinded to the clinical data interpreted the GMPI and CT-AC images. Coronary angiography was considered as the reference standard. The diagnostic efficacy was evaluated based on sex, BMI, and individual coronary arteries. The diagnostic accuracy of GMPI was higher than that of nonattenuation correction overall, as well as for men, overweight individuals, and right CAD (P<0.05). Compared with CT-AC, GMPI overall had a higher specificity (96.3 vs. 86.9%, P=0.014) but the same sensitivity, achieving an increased accuracy and area under the curve (AUC, P>0.05). For diagnosing right CAD, GMPI had a higher diagnostic efficacy (AUC: 0.733 vs. 0.596, P<0.001) because of its higher sensitivity (52.0 vs. 26.0%, P=0.008); for men, the diagnostic efficacy of GMPI was significantly higher than that of CT-AC (AUC: 0.754 vs. 0.681, P=0.038). Both CT-AC and GMPI led to an increased diagnostic efficacy compared with nonattenuation correction in differentiating attenuation artifacts from fixed perfusion defects. These improvements were, however, more obvious for GMPI than for CT-AC, especially in men and right CAD.

Software reproducibility of myocardial blood flow and flow reserve quantification in ischemic heart disease: A 13N-ammonia PET study

BackgroundWe explored agreement in the quantification of myocardial perfusion by cross-comparison of implemented software packages (SPs) in three distinguishable patient profile populations. MethodsWe studied 91 scans of patients divided into 3 subgroups based on their semi-quantitative perfusion findings: patients with normal perfusion, with reversible perfusion defects, and with fixed perfusion defects. Rest myocardial blood flow (MBF), stress MBF, and myocardial flow reserve (MFR) were obtained with QPET, SyngoMBF, and Carimas. Agreement between SPs was considered adequate when a pairwise standardized difference was found to be < 0.20 and its corresponding intraclass correlation coefficient was ≥ 0.75. ResultsIn patients with normal perfusion, two out of three comparisons of global stress MBF quantifications were outside the limits of agreement. In ischemic patients, all comparisons of global stress MBF and MFR were outside the limits of established agreement. In patients with fixed perfusion defects, all SP comparisons of perfusion quantifications were within the limit of agreement. Regionally, agreement of these perfusion estimates was mostly found for the left anterior descending artery vascular territory. ConclusionReversible defects demonstrated the worst agreement in global stress MBF and MFR and discrepancies showed to be regional dependent. Reproducibility between SPs should not be assumed.

RDW Value may Increase the Diagnostic Accuracy of MPS.

Objectives:As the feasibility of obtaining health care has improved in the last decade, there is an increase in the number of performing unnecessary coronary angiogram. Red Cell Distribution Width (RDW), which shows erythrocyte dispersion volume, is associated with coronary artery disease. The present study aims to evaluate the relationship between RDW value and the severity of coronary artery disease in patients who undergo myocardial perfusion scintigraphy (MPS) as an evaluation for coronary ischemia and after which patients had a coronary angiography.Methods:This retrospective study included 452 patients diagnosed as stabile angina that had MPS to evaluate coronary ischemia and after which coronary angiography was performed. Complete blood count was obtained on the same day. Patients were first divided into two groups: patients with and without ischemia on MPS. Then, the group who had ischemia on the MPS where divided into another two groups: patients who had RDW values ≥13.5 and the others who had RDW value <13.5. Patients who had fixed perfusion defect, chronic kidney disease, thyroid dysfunction, hematological disease, those who use iron supplements, and those who had active infectious disease were excluded from this study.Results:The basic characteristics were the same between study groups. We found that severe coronary vessel disease, single vessel, two vessels and three vessels diseases were higher in patients who had ischemia on the MPS and RDW values ≥13.5 (p-value were 0.032, 0.004, 0.042 respectively). RDW values ≥13.5 was found to be an independent predictor for the presence of severe coronary artery disease (p<0.001 OR: 3.55).Conclusion:Patients who have MPS for ischemic evaluation and RDW values of ≥ 13.5 were more severe coronary heart diseases. As a result, the findings suggest that using of RDW value is a cheap and feasible parameter that may prevent performing unnecessary coronary angiography for patients after MPS.