Abnormal Myocardial Perfusion Imaging Research Articles

Comparative Effectiveness of PET and SPECT MPI for Predicting Cardiovascular Events After Kidney Transplant.

Advanced chronic kidney disease is associated with high cardiovascular risk, even after kidney transplant. Pretransplant cardiac testing may identify patients who require additional assessment before transplant or would benefit from risk optimization. The objective of the current study was to determine the relative prognostic utility of pretransplant positron emission tomography (PET) and single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for posttransplant major adverse cardiovascular events (MACEs). We retrospectively followed patients who underwent MPI before kidney transplant for the occurrence of MACE after transplant including myocardial infarction, stroke, heart failure, and cardiac death. An abnormal MPI result was defined as a total perfusion deficit >5% of the myocardium. To determine associations of MPI results with MACE, we utilized Cox hazard regression with propensity weighting for PET versus SPECT with model factors, including demographics and cardiovascular risk factors. A total of 393 patients underwent MPI (208 PET and 185 SPECT) and were followed for a median of 5.9 years post-transplant. Most were male (58%), median age was 58 years, and there was a high burden of hypertension (88%) and diabetes (33%). A minority had abnormal MPI (n=58, 15%). In propensity-weighted hazard regression, abnormal PET result was associated with posttransplant MACE (hazard ratio, 3.02 [95% CI, 1.78-5.11]; P<0.001), while there was insufficient evidence of an association of abnormal SPECT result with MACE (1.39 [95% CI, 0.72-2.66]; P=0.33). The explained relative risk of the PET result was higher than the SPECT result (R2 0.086 versus 0.007). Normal PET was associated with the lowest risk of MACE (2.2%/year versus 3.6%/year for normal SPECT; P<0.001). Kidney transplant recipients are at high cardiovascular risk, despite a minority having obstructive coronary artery disease on MPI. PET MPI findings predict posttransplant MACE. Normal PET may better discriminate lower risk patients compared with normal SPECT, which should be confirmed in a larger prospective study.

Impact of myocardial perfusion and coronary calcium on medical management for coronary artery disease.

Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) remains one of the most widely used imaging modalities for the diagnosis and prognostication of coronary artery disease (CAD). Despite the extensive prognostic information provided by MPI, little is known about how this influences the prescription of medical therapy for CAD. We evaluated the relationship between MPI with computed tomography (CT) attenuation correction and prescription of acetylsalicylic acid (ASA) and statins. We performed a retrospective analysis of consecutive patients who underwent SPECT MPI at a single centre between 2015 and 2021. Myocardial perfusion abnormalities and coronary calcium burden were assessed, with attenuation correction imaging 77.8% of patients. Medication prescriptions before and within 180 days after the test were compared. Associations between abnormal perfusion and calcium burden with ASA and statin prescription were assessed using multivariable logistic regression. In total, 9908 patients were included, with a mean age 66.8 ± 11.7 years and 5337 (53.9%) males. The prescription of statins increased more in patients with abnormal perfusion (increase of 19.2 vs. 12.0%, P < 0.001). Similarly, the presence of extensive CAC led to a greater increase in statin prescription compared with no calcium (increase 12.1 vs. 7.8%, P < 0.001). In multivariable analyses, ischaemia and coronary artery calcium were independently associated with ASA and statin prescription. Abnormal MPI testing was associated with significant changes in medical therapy. Both calcium burden and perfusion abnormalities were associated with increased prescriptions of medical therapy for CAD.

Epicardial fat volume, an independent risk factor for major adverse cardiovascular events, had an incremental prognostic value to myocardial perfusion imaging in Chinese populations with suspected or known coronary artery disease with a normal left ventricular ejection fraction.

Most coronary artery disease (CAD) patients with a normal left ventricular ejection fraction (LVEF) experience a poor prognosis. Single-photon emission computerized tomography (SPECT)-myocardial perfusion imaging (MPI), a routine examination, is useful in assessing risk and predicting major adverse cardiovascular events (MACEs) in populations with suspected or known CAD. SPECT/CT is a "one-stop shop" examination, which, through non-contrast CT, can produce attenuation correction for MPI and obtain information on coronary artery calcium (CAC) and epicardial fat volume (EFV) simultaneously. This study aims to investigate the predictive and incremental value of EFV to MPI for MACE in Chinese populations with suspected or known CAD with a normal LVEF. We retrospectively studied 290 suspected or known CAD inpatients with a normal LVEF who underwent SPECT/CT between February 2014 and December 2017. Abnormal MPI was defined as a summed stress score ≥4 or summed difference score ≥2. EFV and CAC were calculated using non-contrast CT. The end date of follow-ups was in February 2022. The follow-up information was obtained from the clinical case notes of the patients or reviews of telephone calls. MACE was defined as cardiac death, late coronary revascularization ≥3 months after MPI, non-fatal myocardial infarction, angina-related rehospitalization, heart failure, and stroke. During the 76-month follow-up, the event rate was 32.0% (93/290). Univariate and multivariate Cox regression analyses concluded that high EFV (>108.3 cm3) [hazard ratio (HR): 3.3, 95% CI: 2.1-5.2, P < 0.000] and abnormal MPI (HR: 1.8, 95% CI: 1.1-2.8, P = 0.010) were independent risk factors for MACE. The event-free survival of patients with high EFV was significantly lower than that of the low EFV group (log-rank test P < 0.001). In the subgroup with normal MPI, high EFV was associated with reduced event-free survival (log-rank P < 0.01), with a higher annualized event rate (8.3% vs. 1.9%). Adding high EFV to MPI could predict MACEs more effectively, with a higher concordance index (0.56-0.69, P < 0.01), higher global chi square (7.2-41.4, P < 0.01), positive integrated discrimination improvement (0.10, P < 0.01), and net reclassification index (0.37, P < 0.01). In Chinese populations with suspected or known CAD with normal LVEF, high EFV was an independent risk factor for MACE after adjusting for traditional risk factors, CAC and MPI. In subgroups with normal MPI, EFV could also improve risk stratification. Adding EFV to MPI had an incremental value for predicting MACE.

Optimizing stress-only myocardial perfusion imaging: a clinical prediction model to improve patient selection.

Stress-only single photon emission computed tomography myocardial perfusion imaging (MPI) offers numerous advantages in terms of improved workflow, cost and radiation reduction but is currently not widely utilized due to challenges in selecting appropriate patients for this technique. Data from 5959 individuals were used to derive (N = 4018) and validate (N = 1941) a binomial logistic regression model to predict normal stress MPI studies (stress total perfusion deficit < 4%, ejection fraction ≥ 50%). Model performance was analyzed using receiver operator characteristic curves. A simplified point-scoring system was developed and its impact on imaging workflow was assessed. Significant predictors of abnormal vs. normal stress MPI included male sex, age > 65 years, cardiomyopathy, congestive heart failure, myocardial infarction, angina, and pharmacological stress. The final model and simplified scoring system were associated with areas under the curve of 0.81 (95% CI 0.79-0.83) and 0.80 (95% CI 0.79-0.82) in the validation group, respectively. Use of the scoring system was estimated to result in a decrease of 56.5% in the number of non-contributory imaging studies acquired with minimal patient rescheduling. A prediction tool derived from simple clinical information can identify candidates for stress-only MPI studies with a beneficial impact on departmental workflow.

Age-Specific Cardiovascular Risk Factors for Major Adverse Cardiac Events in Patients Undergoing Myocardial Perfusion Imaging.

The prevalence of traditional cardiovascular risk factors shows different age-specific patterns. It is not known whether the prognostic impact of risk factors is similarly age-specific. We evaluated the profiles of cardiovascular risk factors and their prognostic impact on coronary artery disease (CAD) in relation to age. We included 3667 patients with suspected or known CAD undergoing stress myocardial perfusion imaging (MPI). We evaluated the risk for major adverse cardiac events (MACE) within three years from the index MPI in patients belonging to three groups according to age tertile distribution: <59, 59-68, and >68 years. Gender, body mass index, diabetes, hypertension, dyslipidemia, family history of CAD, smoking, angina, dyspnea, previous CAD, and MPI outcome were assessed as risk factors by a multivariable Cox's regression. The three-year risk of MACE increased progressively with age and was 9%, 13%, and 18% for each group, respectively (p < 0.0001). Dyspnea and abnormal MPI outcome were significant risk factors for all age groups. Diabetes and smoking were significant from the age of 59 onwards, while hypertension resulted significant for patients older than 68 years. The number of risk factors was significantly associated with the occurrence of MACE increase with age. It is noteworthy that a personal history of CAD was not useful for risk stratification, while MPI results were.

SPECT for risk stratification in patients with advanced liver disease

BackgroundPatients with advanced liver disease (ALD) have unique hemodynamics including high resting cardiac output and low systemic vascular resistance which may reduce the sensitivity of pharmacological myocardial perfusion imaging (MPI). MPI is frequently ordered for patients with ALD if liver transplantation is being considered. Because of the limited data on effectiveness of MPI in the ALD population, we conducted this cohort study focused on cardiac outcomes after pharmacological MPI. MethodsWe conducted a cohort study comparing normal versus abnormal MPI among 454 patients with ALD between 1/1/2011 and 06/01/2021 at a single tertiarycare academic medical center. Abnormal MPI was defined as summed stress score > 2 on LVEF < 40 %. The primary outcome was to compare the frequency of major adverse cardiovascular events (MACEs) among ALD patients with and without abnormal MPI. Secondary outcome included individual components of MACE analyzed by chi square. Kaplan-Meier survival curves and a logistic-regression model of associations with MACE were also performed. ResultsIn this cohort, 58 patients were observed to have an abnormal MPI. Baseline characteristics between the groups were similar, except prior coronary disease, which was more common among the abnormal MPI group (risk ratio 2.07, 95 % confidence interval 1.30–3.30, P = 0.003). MACE was more common in the group with abnormal MPI (n = 24, 41.4 % versus normal MPI n = 104, 26.3 %, P < .001). No difference in MACE was observed when stratified by liver disease type. In the logistic regression model, diabetes mellitus, stage 3 chronic kidney disease, and summed stress score >2 were retained as being associated with MACE. ConclusionsOur data suggest that MPI remains an effective test for identifying ALD patients at higher risk of mortality and cardiac events. Further study is needed to understand whether a strategy of routine MPI for liver transplant candidates effectively improves long term survival.

Association between Cardiovascular Risk Factors and High-Risk Features in Myocardial Perfusion Imaging: A Multicenter Study.

Myocardial perfusion imaging (MPI) is a noninvasive method with acceptable sensitivity and specificity in diagnosing coronary artery disease (CAD) in moderate-risk patients, including those with CAD risk factors. The present cross-sectional, prospective study was conducted on 4886 patients from April 2020 through March 2023 at Chamran and Tehran Heart Center hospitals. A questionnaire regarding anthropometric variables, demographic characteristics, CAD risk factors, and MPI findings was designed. Totally, 2179 patients (44.6%) had abnormal MPI. Patients with abnormal MPI were significantly older than those with normal MPI. Older age (OR, 1.64; 95% CI, 1.2 to 1.72; P<0.001), diabetes mellitus (DM) (OR, 1.36; 95% CI, 1.1 to 1.48; P=0.012), hypertension (OR, 1.24; 95% CI, 1.04 to 1.37; P=0.032), and dyslipidemia (OR, 1.54; 95% CI, 1.25 to 1.8; P<0.001) were associated with abnormal MPI independently. Patients with more CAD risk factors were more likely to have abnormal MPI. Thus, in patients without or at most with 1 risk factor and those with 8 CAD risk factors, the likelihood of abnormal MPI was 3.7% and 76.2%, respectively. The frequency of left ventricular dilation and right ventricular prominence was significantly higher in patients with older age (P<0.001 and P=0.043, respectively), dyslipidemia (P<0.001 and P=0.007, respectively), DM (P<0.001 and P<0.001, respectively), and hypertension (P=0.048 and P=0.057, respectively). Individuals with CAD risk factors, especially those with older age, DM, hypertension, or dyslipidemia, require meticulous attention during CAD evaluation, particularly via MPI.

Myocardial perfusion imaging by 15O-H2O positron emission tomography predicts clinical revascularization procedures in symptomatic patients with previous coronary artery bypass graft.

We wanted to assess if 15O-H2O myocardial perfusion imaging (MPI) in a clinical setting can predict referral to coronary artery catheterization [coronary angiography (CAG)], execution of percutaneous coronary intervention (PCI), and post-PCI angina relief for patients with angina and previous coronary artery bypass graft (CABG). We analysed 172 symptomatic CABG patients referred for 15O-H2O positron emission tomography (PET) MPI at Aarhus University Hospital Department of Nuclear Medicine & PET Centre, of which five did not complete the scan. In total, 145 (87%) enrolled patients had an abnormal MPI. Of these, 86/145 (59%) underwent CAG within 3 months; however, no PET parameters predicted referral to CAG. During the CAG, 25/86 (29%) patients were revascularized by PCI. Relative flow reserve (RFR) (0.49 vs. 0.54 P = 0.03), vessel-specific myocardial blood flow (MBF) (1.53 vs. 1.88 mL/g/min, P < 0.01), and vessel-specific myocardial flow reserve (MFR) (1.73 vs. 2.13, P < 0.01) were significantly lower in patients revascularized by PCI. Receiver operating characteristic analysis of the vessel-specific parameters yielded optimal cutoffs of 1.36 mL/g/min (MBF) and 1.28 (MFR) to predict PCI. Angina relief was experienced by 18/24 (75%) of the patients who underwent PCI. Myocardial blood flow was an excellent predictor of angina relief on both a global [area under the curve (AUC) = 0.85, P < 0.01] and vessel-specific (AUC = 0.90, P < 0.01) level with optimal cutoff levels of 1.99 mL/g/min and 1.85 mL/g/min, respectively. For CABG patients, RFR, vessel-specific MBF, and vessel-specific MFR measured by 15O-H2O PET MPI predict whether subsequent CAG will result in PCI. Additionally, global and vessel-specific MBF values predict post-PCI angina relief.

Prognostic value of combined coronary angiography-derived IMR and myocardial perfusion imaging by CZT SPECT in INOCA

BackgroundA significant proportion of ischemia with non-obstructive coronary artery disease (INOCA) demonstrate coronary microvascular dysfunction (CMD), a condition associated with abnormal myocardial perfusion imaging (MPI) and adverse outcomes. Coronary angiography-derived index of microvascular resistance (caIMR) is a novel non-invasive technique to assess CMD. We aimed to investigate the prognostic value of combined caIMR and MPI by CZT SPECT in INOCA patients. MethodsConsecutive 151 patients with chest pain and < 50% coronary stenosis who underwent coronary angiography and MPI within 3 months were enrolled. caIMR was calculated by computational pressure-flow dynamics. CMD was defined as caIMR ≥ 25. The endpoint was major adverse cardiac events (MACE: cardiovascular death, nonfatal myocardial infarction, revascularization, angina-related rehospitalization, heart failure, and stroke). ResultsOf all INOCA patients, CMD was present in 93 (61.6%) patients. The prevalence of abnormal MPI was significantly higher in CMD compared with non-CMD patients (40.9% vs 13.8%, P < .001). CMD showed a higher risk of MACE than non-CMD patients. Patients with both CMD and abnormal MPI had the worst prognosis, followed by patients with CMD and normal MPI (log-rank P < .001). Cox regression analysis identified CMD (HR 3.121, 95%CI 1.221-7.974, P = .017) and MPI (HR 2.704, 95%CI 1.030-7.099, P = .043) as predictive of MACE. The prognostic value of INOCA patients enhanced significantly by adding CMD and MPI to the model with clinical risk factors (AUC = 0.777 vs 0.686, P = .030). ConclusioncaIMR-derived CMD is associated with increased risk of MACE among INOCA patients. Patients with abnormalities on both caIMR and MPI had the worse outcomes. Graphical abstract▪

The Utility of Coronary CT Angiography in Evaluating Symptomatic Patients with Positive MPI Referred for Coronary Angiography: A Single-center Experience

Background: Patients with suspected or known coronary artery disease (CAD) can be challenging to evaluate. Our study aims to assess the efficacy and utility of coronary computed tomographic angiography (CCTA) as a diagnostic method in patients with abnormal myocardial perfusion imaging (MPI) who were initially referred for Invasive Coronary Angiography (ICA). Methods: This is a single-center retrospective descriptive study. We evaluated 210 patients who underwent CCTA instead of ICA. Data of these patients were documented and analyzed accordingly. Results: Of the 210 patients who underwent CCTA, the procedure was found to be diagnostic in 172 (81.9%) patients. Of these 172 patients, 152 (88.4%) had normal coronaries or minor CAD, and 20 (11.6%) had significant disease requiring subsequent ICA. In 38 (18.1%) patients out of the total cohort, the CCTA was not diagnostic or could not be performed due to technical difficulties, requiring either ICA or another ischemia evaluation diagnostic modality. Conclusion: CCTA is a viable and reliable diagnostic tool for evaluating patients with suspected CAD referred for ICA following an abnormal MPI test. It is recommended as an initial test to rule out significant coronary stenosis and as it can avoid unnecessary ICA.

Comparison of myocardial perfusion between the users of two antiepileptic medications: valproate vs. carbamazepine.

The prevalence of coronary artery disease (CAD) is high in patients with epilepsy using antiepileptic drugs (AED). Epilepsy, AED, or the type and duration of AED use , may contribute to higher CAD risk.In this study, myocardial perfusion imaging (MPI) was compared between patients using carbamazepine and valproate. Out of 73 patients receiving carbamazepine or valproate monotherapy for more than 2 years, visited at a tertiary referral clinic, 32 patients participated in a 2-day stress and rest phases MPI. For each phase, 15-25 mCi 99mTc-MIBI was injected, at peak exercise or by pharmacologic stimulation for the stress phase. SPECT with cardiac gating was done by a dual-head gamma camera and processed and quantified. Scans with at least one definite reversible hypo-perfusion segment were considered abnormal. Seventeen patients received carbamazepine monotherapy and 15 valproates. Age and duration of AED use were similar between the groups. Two scans were abnormal (6.3%) both in valproate group (13.3%). Duration of AED use was higher in patients with abnormal scans. In patients receiving monotherapy >2 years, the frequency of abnormal MPI was similar between groups (P-value=0.12). In patients receiving monotherapy > 5 years, prevalence of abnormal MPI was higher in the valproate group (28.6% vs. 0.0%; P-value=0.042). Considering valproate subgroup, ischemic patients had higher duration of AED use, comparing with the normal patients (17.0±4.2 vs. 6.4±4.8, P-value=0.014). MPIs were abnormal in patients receiving valproate after 5 years compared to patients receiving carbamazepine. Long-term valproate use may increase the risk of CAD.

Agreement between Thai Cardiovascular Risk Scores and Myocardial Perfusion Imaging: Exploring Associations and Clinical Implications.

This study aimed to assess the agreement between the Thai cardiovascular (CV) risk score or pretest probability (PTP), and myocardial perfusion imaging (MPI), and to explore the association between abnormal MPI results and higher Thai CV risk scores or PTP risk. The study was conducted between March 2017 and December 2021, and included 128 patients. Myocardial perfusion gated single photon emission computed tomography imaging was performed on all patients, and agreement between the Thai CV risk score, PTP, and MPI was measured using weighted Cohen's kappa statistic. Logistic regression was used to calculate odds ratios (OR) and explore the association. Fair agreement was observed between MPI and the Thai CV risk score (κ =0.269, P = 0.010), including patients with clinical chest pain (κ =0.367, P < 0.001). Subgroup analysis of patients with intermediate PTP revealed moderate agreement between MPI and the Thai CV risk score (κ =0.428, P = 0.002). Patients with intermediate (OR = 3.25, P = 0.010) or high (OR = 4.78, P = 0.001) Thai CV risk scores had significantly higher odds of having intermediate or high MPI results compared to those with low Thai CV risk scores. This study highlights the agreement between MPI and the Thai CV risk score and PTP. Higher Thai CV risk scores are associated with increased odds of abnormal MPI results. These findings provide valuable insights for clinical decision-making and patient management.

Effect of nonobstructive coronary stenosis on coronary microvascular dysfunction and long‐term outcomes in patients with INOCA

Ischemic pain with no-obstructive coronary artery (INOCA) is clinically significant and defined by nonobstructive coronary stenosis <50%. Coronary microvascular dysfunction (CMD) is a relevant cause associated with adverse outcomes. Investigated the effect of no-stenosis (0% stenosis) and non-obstructive (0% < stenosis < 50%) on the prognostic impact of CMD in INOCA. A retrospective study assessed the coronary microvascular function in 151 INOCA patients who underwent invasive angiography by the coronary angiography-derived index of microcirculation-resistance (caIMR). CZT-SPECT was performed to evaluate myocardial perfusion imaging (MPI) abnormalities. Chi-square test/Fisher exact test, Student t-test, Kaplan-Meier curve, and Uni-multivariable Cox proportional models were used for analysis. Clinical outcomes were major adverse cardiovascular events (MACE) during a median follow-up of 35 months. No-stenosis was present in 71 (47%) INOCA patients, and 80 (53%) were with nonobstructive. CMD (caIMR ≥ 25) was more prevalent in patients with no-stenosis than nonobstructive (76.1% vs. 48.8%, p = .001), along with abnormal MPI (39.4% vs. 22.5%, p = .024). The MACE rates were not different between no-stenosis and nonobstructive stenosis. CMD showed an increased risk of MACE for all INOCA. No-stenosis with CMD had the worst prognosis. Cox regression analysis identified CMD and abnormal MPI as predictors of MACE in all INOCA and patients with no-stenosis. However, no-stenosis and nonobstructive stenosis were not predictors of MACE in INOCA. CMD was more frequently present in INOCA with no-stenosis. However, there was no difference in long-term clinical outcomes between no-stenosis and nonobstructive stenosis. CMD could independently predict poor outcomes in INOCA, particularly in patients with no-stenosis.

Impact of the COVID-19 pandemic on the use of myocardial perfusion imaging for the assessment of coronary artery disease: a Brazilian experience

The COVID-19 pandemic and the lockdown period caused deep effects on healthcare, including cardiac imaging, with a possible negative influence on the evaluation of coronary artery disease (CAD). This study aimed to evaluate the impact of the COVID-19 pandemic on myocardial perfusion imaging (MPI) performance and results in a Brazilian, Nuclear Cardiology laboratory. Patients with or without known CAD who underwent MPI in three 30-day periods (pre-pandemic [mid-February to mid-March 2020], lockdown [April-May 2020], and post-lockdown [August 2020]) were studied. MPI volumes dropped from 204 pre-lockdown to 43 during lockdown (78.9% reduction), rising to 248 after lockdown. The use of pharmacologic stress increased from 36.3% to 53.5% during lockdown. The frequency of abnormal MPI tests did not differ significantly among the time intervals, as well as the frequency of myocardial ischemia. Younger age, ≥1 cardiac risk factor, and known CAD were independent predictors of the performance of MPI during the lockdown period. In conclusion, a large reduction of MPI performance occurred during lockdown, when imaging was sought mainly by younger patients, with cardiac risk factors or known CAD. There was no significant difference in the frequency of abnormal MPI or of myocardial ischemia among the periods, which might indicate missed cases of CAD during lockdown; therefore, the consequences of cardiac testing reductions should be continuously assessed.

Correlation of left ventricular mechanical dyssynchrony in patients with chronic kidney disease using phase analysis of gated single photon emission computed tomography myocardial perfusion imaging

Abstract Background Left ventricular mechanical dyssynchrony (LVMD) possesses deleterious effects that have been neglected in chronic kidney disease (CKD) as a cause of left ventricular dysfunction and further progression to heart failure, possibly contributing to sudden cardiac death in this population. Thus, cardiovascular risk assessment is essential in early stages of CKD as well as in the pre-transplant screening and this can be performed non-invasively by modalities including phase analysis Gated-SPECT myocardial perfusion imaging (MPI). This modality has emerged as a prognostic tool to predict mortality independent of MPI abnormalities as well as assessment of ventricular synchrony. Purpose The goal of this study is to evaluate the relationship of left ventricular mechanical dyssynchrony using phase analysis G-SPECT and chronic kidney disease severity and its predictors. Methods We included 567 patients who underwent one day rest/stress (dipyridamole) 99mTc-sestamibi myocardial perfusion imaging with G-SPECT for the following indications for testing: detection of CAD among asymptomatic patients, risk assessment during pre-operative evaluation for kidney transplantation and evaluation for noncardiac surgery without active cardiac conditions between January 2017 to January 2021. Data was collected including gender, age, risk factors resting heart rate and baseline blood pressure. Gated SPECT-MPI was performed according to the protocol rest followed by stress images (dipyridamole) 99mTc-sestamibi. The rest and stress phase analysis (histogram bandwidth, standard deviation of phase and entropy) parameters were compared between the five stages of chronic kidney disease. Data of the stress-rest difference in dyssynchrony was analyzed using McNemar's test; crude odds ratios and adjusted odds or multivariate analysis were done. Results Advanced CKD (Stage 4–5) shows statistically significant correlation with the Histogram bandwidth (HBW) both at stress (p=0.008) and rest (p=0.018), and stress entropy (p=0.007). As for the other stages, LVMD is present with similar results seen with the phase parameters HBW and PSD, the entropy values at rest than at stress for Stages I to IV (p&amp;lt;0.05). On further analysis, abnormal perfusion showed to be an independent predictor of left ventricular mechanical dyssynchrony across all arms. Other associated factors includes advanced CKD (stages 4–5), male sex, BMI ≥30 kg/m2, blood pressure and resting heart rate were significantly associated with increased odds of dyssynchrony across stress and rest tests. Overall, the full models were statistically significant, with R-squared ranging from 14.96% to 30.11% (p&amp;lt;0.001). Conclusion This study showed that CKD patients have left ventricular mechanical dyssynchrony on gated-SPECT MPI. Hence, it can be used as an alternative for early assessment and guide decision making for the treatment of patients with CKD to prevent further cardiovascular complication. Funding Acknowledgement Type of funding sources: None.

Myocardial perfusion imaging single photon emission computed tomography may detect silent myocardial ischemia in patient with epilepsy.

The aim of the present study was to compare the myocardial perfusion imaging (MPI) with [99mTc]tetrofosmin stress - rest single-photon emission computer tomography (SPECT) of patients with epilepsy with matched control individuals. All 29 adult epileptic patients were receiving antiepileptic drugs (AEDs) for epilepsy. Thirty-two individuals matched for gender and age consisted of the control group. MPIs SPECT were performed, and myocardial summed scores were obtained during stress (SSS) and rest (SRS) images. Abnormal MPI was considered when SSS was ≥ 4. In addition, the difference (SDS) between SSS and SRS was also assessed, which represents a rate of reversibility after stress. Twenty of 29 (68.97%) patients with epilepsy had abnormal MPI and 14/32 (43.75%) of the controls (p = 0.04). Among males, 18/23 patients and 11/25 controls had abnormal MPI (p = 0.01), with quite a significant difference for mean SSS between male patients and controls (p = 0.002). Furthermore, SDS comparison showed that irreversible abnormalities were more common in patients than in control individuals. A difference of inadequately compensated myocardial ischemia between patients treated with enzyme inducing AEDs and patients treated with valproic acid was also detected. Single-photon emission computer tomography (SPECT) may detect increased risk for coronary artery disease and further cardiovascular events in patients with epilepsy. Our findings favor the conclusion that SPECT could be used for the early identification of cardiovascular comorbidity in epilepsy.

Clinical impact of quantitative [15O] H2O PET/CT myocardial perfusion imaging on decision-making regarding invasive management of coronary artery disease

BackgroundThis study was performed to determine the impact of oxygen-15-labeled water ([15O] H2O) positron emission tomography/computed tomography (PET/CT) myocardial perfusion imaging (MPI) on referral for invasive coronary angiography (ICA) and revascularization. MethodsThis study involved 57 patients who underwent [15O] H2O PET/CT MPI for evaluation of coronary artery disease (CAD). Data of referral for ICA and revascularization, clinical symptoms, and cardiac events within 6 months after MPI were assessed. Logistic regression was used to determine the predictors for referral and revascularization. The diagnostic values of hyperemic myocardial blood flow (MBF) and coronary flow reserve (CFR) were calculated. ResultsNormal and abnormal MPI findings were observed in 18 (32%) and 39 (68%) patients, respectively. The referral rate was significantly different between the normal and abnormal MPI groups (5.6% and 48.7%, respectively; P = .002). Revascularization rate of abnormal MPI group was 40.0%. There were significant differences of hyperemic MBF and CFR between patients with and without referral. Hyperemic MBF was significant predictor for referral (OR 15.24, 95% CI 3.39-68.55, P < .005) and revascularization (OR 28.57, 95% CI 3.08-265.33, P < .005). Conclusion[15O] H2O PET/CT MPI showed a clinical impact on decision-making regarding invasive procedure for management of CAD.

3D fusion between fluoroscopy angiograms and SPECT myocardial perfusion images to guide percutaneous coronary intervention

BackgroundPercutaneous coronary intervention (PCI) in stable coronary artery disease (CAD) is commonly triggered by abnormal myocardial perfusion imaging (MPI). However, due to the possibilities of multivessel disease, serial stenoses and variability of coronary artery perfusion distribution, an opportunity exists to better align anatomic stenosis with perfusion abnormalities to improve revascularization decisions. This study aims to develop a multi-modality fusion approach to assist decision-making for PCI. Methods and ResultsCoronary arteries from fluoroscopic angiography (FA) were reconstructed into 3D artery anatomy. Left ventricular (LV) epicardial surface was extracted from SPECT. The artery anatomy and epicardial surface were non-rigidly fused. The accuracy of the 3D fusion was evaluated via both computer simulation and real patient data. Simulated FA and MPI were integrated and then compared with the ground truth from a digital phantom. The distance-based mismatch errors between simulated fluoroscopy and phantom arteries were 1.86 ± 1.43 mm for left coronary arteries (LCA) and 2.21 ± 2.50 mm for right coronary arteries (RCA). FA and SPECT images in 30 patients were integrated and then compared with the ground truth from CT angiograms. The distance-based mismatch errors between the fluoroscopy and CT arteries were 3.84 ± 3.15 mm for LCA and 5.55 ± 3.64 mm for RCA. The presence of the corresponding fluoroscopy and CT arteries in the AHA-17-segment model agreed well with a Kappa value of 0.91 (CI 0.89-0.93) for LCA and a Kappa value of 0.80 (CI 0.67-0.92) for RCA. ConclusionsOur fusion approach is technically accurate to assist PCI decision-making and is clinically feasible to be used in the catheterization laboratory. Future studies are necessary to determine if fusion improves PCI-related outcomes.

Impact of Gd-153 scanning line source attenuation correction on downstream invasive testing

BackgroundAttenuation correction (AC) using hardware and software solutions has been shown to increase the specificity of SPECT MPI by decreasing false positive results and improving prognostic ability. Theoretically this should reduce downstream testing and unnecessary costs. We sought to assess the consequences of the use of Gd-153 scanning line source attenuation correction during SPECT myocardial perfusion imaging (MPI) on downstream invasive testing. MethodsAll patients who underwent a clinically indicated Tc-99m stress SPECT MPI study from 2013 to 2015 at five hospitals (2 with AC and 3 without) were retrospectively reviewed. Patient demographics, results of testing, subsequent coronary angiography within 3 months, and revascularization were recorded. The results of the MPI studies, downstream angiogram utilization, and results of angiography were compared and a propensity matched subgroup analysis was performed. ResultsA total of 9968 patients underwent SPECT MPI during the study time period (6106 performed with AC and 3862 without). Out of 3928 patients included in the propensity matched cohort, there was no difference in the proportion of abnormal MPI results between the two groups (31.5% vs 30.4%, P = 0.47), however, more patients underwent coronary angiography within 90 days in the AC group (10.6% vs 8.7%, P = 0.05). There was no significant difference in the proportion of patients with angiographically significant obstructive disease (53.4% vs 56.1%, P = 0.19), however, fewer patients in the AC group with obstructive coronary disease were revascularized (36.1% vs 46.8%, P = 0.04). The findings remained consistent after sub-group analysis in patients without known coronary disease. ConclusionThe use of scanning line source AC did not meaningfully influence the rate of abnormal MPI results or downstream invasive testing in this cohort. The clinical utility of scanning line source AC may be limited to facilitating stress-first imaging protocols.

The prognostic and diagnostic implications of surveillance serial myocardial perfusion imaging in asymptomatic renal transplant candidates

BackgroundThe utility of serial SPECT myocardial perfusion imaging (MPI) for CAD surveillance in asymptomatic ESRD patients awaiting kidney transplantation (KT) is uncertain. Methods and ResultsWe retrospectively investigated 700 asymptomatic KT candidates with ≥ 2 pre-transplant SPECT-MPIs (mean interval, 20 ± 13 months). Worsening MPI was defined as total perfusion deficit increase (ΔTPD) > 5%. High clinical risk was defined as ≥ 3 AHA/ACC KT risk factors. The primary outcome was major adverse cardiac events (MACE) of cardiac death or myocardial infarction. The initial MPI was normal in 462 (66%) subjects. On repeat MPI, ΔTPD > 5% was observed in 82 (12%) subjects, and the incidence increased with increasing time gap between MPIs (P = .006). During a mean follow-up of 16 ± 8 months, there were 119 (17%) MACEs. In the entire cohort, ΔTPD > 5% was not significantly associated with MACE (HR = 1.38; P = .210). ΔTPD > 5% was associated with increased MACE rate among patients with normal initial MPI (HR = 2.30; P = .005), but not among those with abnormal initial MPI (P = .260). There was a significant interaction between ΔTPD > 5% and initial MPI normalcy status in predicting MACE (interaction P = .018), such that the predictive value of ΔTPD is dependent on the initial MPI normalcy. Among subjects with normal initial MPI, ΔTPD > 5% was significantly associated with MACE only if the sum of KT risk factors was ≥ 3 (HR = 2.26; P = .016). Among 123 patients who underwent coronary angiography, ΔTPD > 5% was associated with a higher prevalence of obstructive CAD when the initial MPI was normal and the sum of KT risk factors was ≥ 3. ConclusionAmong patients with ESRD waitlisted for KT, new/worsening MPI abnormalities are expected. On serial surveillance, ΔTPD > 5% is associated with MACE and obstructive CAD among those with a normal initial MPI and ≥ 3 AHA/ACC KT risk factors.