Perfusion Cardiac Magnetic Resonance Imaging Research Articles

Pulmonary Artery Angioplasty for Improving Ipsilateral Lung Perfusion in Adolescent and Adult Patients: An Analysis Based on Cardiac Magnetic Resonance Imaging and Lung Perfusion Scanning.

The left pulmonary artery (LPA) may be kinked and stenotic, especially in tetralogy of Fallot, because of ductal tissue and anterior deviation of the conal septum. If LPA stenosis is not effectively treated during total correction, surgical angioplasty is occasionally performed. However, whether pulmonary artery (PA) angioplasty in adolescents or adults improves perfusion in the ipsilateral lung remains unclear. This retrospective review enrolled patients who underwent PA angioplasty for LPA stenosis between 2004 and 2019. Among patients who underwent a lung perfusion scan (LPS) or cardiac magnetic resonance imaging (cMRI) pre- and post-pulmonary angioplasty, those aged >13 years with <40% left lung perfusion (p-left) in the pre-angioplasty study were included. Preoperative and postoperative computed tomography, LPS, and cMRI data were collected. The perfusion ratio was analyzed according to the LPA's anatomical characteristics. Seventeen adolescents and 16 adults (≥18 years old) were finally included (median age, 17 years). The most common primary diagnosis was tetralogy of Fallot (87.9%). In all patients, LPA angioplasty was performed concomitantly with right ventricular outflow tract reconstruction. No patients died. Preoperative p-left was not significantly different between adolescents and adults; however, adolescents had significantly higher postoperative p-left than adults. P-left significantly increased in adolescents, but not in adults. Seven patients had significant stenosis (z-score <-2.0) confined only to the proximal LPA and demonstrated significantly increased p-left. PA angioplasty significantly increased ipsilateral lung perfusion in adolescents. If focal stenosis is confined to the proximal LPA, PA angioplasty may improve ipsilateral lung perfusion, regardless of age.

Association of Pulmonary Transit Time and Pulmonary Blood Volume From First-Pass Perfusion Cardiac MRI With Diastolic Dysfunction and Left Ventricle Deformation in Restrictive Cardiomyopathy.

Patients with restrictive cardiomyopathy (RCM) have impaired diastolic filling and hemodynamic congestion. Pulmonary transit time (PTT) and pulmonary blood volume index (PBVi) reflect the hemodynamic status, but the relationship with left ventricle (LV) dysfunction remains unclear. To evaluate the PTT and PBVi in RCM patients, the association with diastolic dysfunction and LV deformation, and the effects on the occurrence of major adverse cardiac events (MACE) in RCM patients. Retrospective. 137 RCM patients (88 men, age 58.80 ± 10.83 years) and 68 age- and sex-matched controls (46 men, age 57.00 ± 8.59 years). 3.0T/Balanced steady-state free precession sequence, recovery prepared echo-planar imaging sequence, and phase-sensitive inversion recovery sequence. The LV function and peak strain (PS) parameters were measured. The PTT was calculated and corrected by heart rate (PTTc). The PBVi was calculated as the product of PTTc and RV stroke volume index. Chi-squared test, student's t-test, Mann-Whitney U test, Pearson's or Spearman's correlation, multivariate linear regression, Kaplan-Meier survival analysis, and Cox regression models analysis. A P-value <0.05 was considered statistically significant. The PTTc showed a significant correlation with the E/A ratio (r = 0.282), and PBVi showed a significant correlation with the E/e' ratio, E/A ratio, and diastolic dysfunction stage (r = 0.222, 0.320, and 0.270). PTTc showed an independent association with LVEF, LV circumferential PS, and LV longitudinal PS (β = 0.472, 0.299, and 0.328). In Kaplan-Meier analysis, higher PTTc and PBVi were significantly associated with MACE. In multivariable Cox regression analysis, PTTc was a significantly independent predictor of the MACE in combination with both cardiac MRI functional and tissue parameters (hazard ratio: 1.23/1.32, 95% confidence interval: 1.10-1.42/1.20-1.46). PTTc and PBVi are associated with diastolic dysfunction and deteriorated LV deformation, and PTTc independently predicts MACE in patients with RCM. 3 TECHNICAL EFFICACY: Stage 2.

Coronary microvascular dysfunction: prevalence and aetiology in patients with suspected myocardial ischaemia

To evaluate the prevalence, aetiology, and corresponding morbidity of coronary microvascular dysfunction (CMD) in patients with suspected myocardial ischaemia. The present study included 115 patients with suspected myocardial ischaemia who underwent stress perfusion cardiac magnetic resonance imaging. CMD was assessed visually based on the myocardial perfusion results. The CMR-derived myocardial perfusion reserve index (MPRI) and left ventricular (LV) strain parameters obtained using the post-processing software CVI42 were employed to evaluate LV myocardial perfusion and deformation. LV strain parameters included global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS), global systolic/diastolic longitudinal, circumferential, and radial strain rates (SLSR, SCSR, SRSR, DLSR, DCSR, and DRSR). Of the 115 patients, 12 patients were excluded and 103 patients were finally included in the study. CMD was observed in 79 % (81 patients, aged 53±12 years) of patients. Regarding aetiology, 91 (88 %) patients had non-obstructive coronary artery disease (CAD), eight (8 %) had obstructive CAD, and four (4 %) had hypertrophic cardiomyopathy (HCM). The incidence of CMD was highest (100 %) in patients with HCM, followed by those with non-obstructive CAD (up to 79 %). There were no statistical differences between CMD and non-CMD groups in GCS, GRS, GLS, SRSR, SCSR, SLSR, DCSR, DRSR and DLSR. The incidence of CMD was higher in patients with signs and symptoms of ischaemia. CMD occurred with non-obstructive CAD, obstructive CAD, and HCM, with the highest prevalence of CMD in HCM.

CMR 3-81 - Changes in Myocardial Perfusion After Coronary Sinus Reducer Implantation for Refractory Angina – Assessment Using Fully Automated Quantitative Stress Perfusion Cardiac MRI

CMR 3-81 - Changes in Myocardial Perfusion After Coronary Sinus Reducer Implantation for Refractory Angina – Assessment Using Fully Automated Quantitative Stress Perfusion Cardiac MRI

Enhanced External Counterpulsation for Management of Postacute Sequelae of SARS-CoV-2 Associated Microvascular Angina and Fatigue: An Interventional Pilot Study.

Postacute sequelae of SARS-CoV-2 infection (PASC) are a novel clinical syndrome characterized in part by endothelial dysfunction. Enhanced external counterpulsation (EECP) produces pulsatile shear stress, which has been associated with improvements in systemic endothelial function. To explore the effects of EECP on symptom burden, physical capacity, mental health, and health-related quality of life (HRQoL) in patients with PASC-associated angina and microvascular dysfunction (MVD). An interventional pilot study was performed, including 10 patients (male = 5, mean age 50.3 years) recruited from a tertiary specialized PASC clinic. Patients with angina and MVD, defined as index of microcirculatory resistance (IMR) ≥25 and/or diagnosed through stress perfusion cardiac magnetic resonance imaging, were included. Patients underwent one modified EECP course (15 one-hour sessions over five weeks). Symptom burden, six-minute walk test, and validated generic self-reported instruments for measuring psychological distress and HRQoL were assessed before and one month after treatment. At baseline, most commonly reported PASC symptoms were angina (100%), fatigue (80%), and dyspnea (80%). Other symptoms included palpitations (50%), concentration impairment (50%), muscle pain (30%), and brain fog (30%). Mean IMR was 63.6. After EECP, 6MWD increased (mean 29.5 m, median 21 m) and angina and fatigue improved. Mean depression scores showed reduced symptoms (-0.8). Mean HRQoL scores improved in seven out of eight subscales (+0.2 to 10.5). Patients with PASC-associated angina and evidence of MVD experienced subjective and objective benefits from EECP. The treatment was well-tolerated. These findings warrant controlled studies in a larger cohort.

Adenosine-induced splenic switch-off on [15O]H2O PET perfusion for the assessment of vascular vasodilatation

BackgroundSplenic switch-off (SSO) is a marker of adequate adenosine-induced vasodilatation on cardiac magnetic resonance perfusion imaging. We evaluate the feasibility of quantitative assessment of SSO in myocardial positron emission tomography (PET) perfusion imaging using [15O]H2O.MethodsThirty patients underwent [15O]H2O PET perfusion with adenosine stress. Time-activity curves, as averaged standardized uptake values (SUVavg), were extracted from dynamic PET for spleen and liver. Maximum SUVavg, stress and rest spleen-to-liver ratio (SLR), and the splenic activity concentration ratio (SAR) were computed. Optimal cut-off values for SSO assessment were estimated from receiver operating characteristics (ROC) curve for maximum SUVavg and SLR. Also, differences between coronary artery disease, myocardial ischemia, beta-blockers, and diabetes were assessed. Data are presented as median [interquartile range].ResultsIn concordance with the SSO phenomenon, both the spleen maximum SUVavg and SLR were lower in adenosine stress when compared to rest perfusion (8.1 [6.5, 9.2] versus 16.4 [13.4, 19.0], p < 0.001) and (0.81 [0.63, 1.08] versus 1.86 [1.73, 2.06], p < 0.001), respectively. During adenosine stress, the SSO effect was most prominent 40–160 s after radiotracer injection. Cut-off values of 12.6 and 1.57 for maximum SUVavg and SLR, respectively, were found based on ROC analysis. No differences in SAR, SLRRest, or SLRStress were observed in patients with coronary artery disease, myocardial ischemia, or diabetes.ConclusionsSSO can be quantified from [15O]H2O PET perfusion and used as a marker for adequate adenosine-induced vasodilatation response. In contrary to other PET perfusion tracers, adenosine-induced SSO is time dependent with [15O]H2O.

The left main coronary artery (LMCA) physiology study: comprehensive clinical haemodynamic evaluation of physiology and pathophysiology

Abstract Background &amp; Purpose At present, physiological evaluation of left main coronary artery (LMCA) disease is based on the assumption that pressure-based indices are agnostic to the vessel being assessed. We conducted mechanistic studies to determine whether pressure-based indices in the left anterior descending (LAD) and left circumflex (LCx) arteries are different and if so, the basis of this discrepancy, in patients with normal coronary arteries (LMCA Physiology Study) and in those with isolated LMCA disease (LMCA Pathophysiology Study). Methods Patients with exertional angina were prospectively enrolled after baseline investigation of computed tomography or invasive angiography and those with left ventricular impairment were excluded. Eligibility for the Physiology Study required the absence of epicardial disease on angiography and/or fractional flow reserve or significant coronary microvascular disease (LAD coronary flow reserve (CFR) &amp;lt;2.0). Simultaneous intracoronary pressure and Doppler measurements were performed in the LAD and LCx arteries, at rest and adenosine mediated hyperaemia. A subset also underwent 3-Tesla quantitative stress perfusion cardiac magnetic resonance imaging. Eligibility for the Pathophysiology Study required isolated LMCA disease, which was verified physiologically by pressure wire pullback according to predefined criteria of 1) ≥80% of total FFR arising from the left main coronary artery disease and 2) ≤0.05 FFR gradient distal to the left main coronary artery disease in both vessels. A paired 2-tailed test for significance was performed for all analyses. The protocols were approved by the UK National research ethics committee. Results 71 patients were prospectively enrolled, 28 in the Physiology Study and 43 in the Pathophysiology Study (Table 1). In the LMCA Physiology Study, CFR was higher and hyperaemic microvascular resistance (hMR) lower in the LAD compared to the LCx. In the LMCA Pathophysiology Study, the contribution to total FFR of downstream disease was negligible and comparable in both branches. Moreover, hyperaemic, and non-hyperaemic pressure-based indices were all significantly lower in the LAD, compared to the LCx. In addition, CFR was higher and hMR lower in the LAD compared to the LCx. Correlations are outlined in Figure 1. Differences in pressure-derived measurements remained after correction for the influence of hydrostatic pressures. However, when adjusted for subtended myocardial mass, there was no significant difference in invasive hemodynamic indices or quantitative perfusion analysis-derived myocardial perfusion reserve index. Conclusions Commonly used indices of stenosis severity are not agnostic to the vessel assessed due to differences in myocardial mass and microvascular resistances. The need for vessel-specific thresholds has significant implications on LMCA disease assessment and potentially, interpretation of the existing evidence base on physiological assessment of non-LMCA disease.Table 1Figure 1

Changes in myocardial perfusion after coronary sinus reducer implantation for refractory angina - assessment using fully automated quantitative stress perfusion cardiac MRI

Abstract Introduction Previous reports show angina improvement after Coronary Sinus Reducer (CSR) implantation [1,2]. However, the mechanistic basis remains unconfirmed. Preliminary studies using semi-quantitative metrics derived from stress perfusion cardiac MRI (CMR), have suggested improved myocardial perfusion particularly in ischaemic segments [3]. To date, assessment by fully automated quantitative myocardial perfusion CMR has not been reported. Purpose To assess the effect of CSR implantation on quantitative regional myocardial blood flow in patients with refractory angina and advanced coronary artery disease (CAD). Methods Prospective cohort study of patients undergoing CSR implantation. CMR was performed at baseline and median 7 months follow-up. Automated segmentation into a 16-segment American Heart Association model was performed to quantify segmental rest and stress myocardial blood flow (MBF, ml/min/g) and myocardial perfusion reserve (MPR). Rest MBF was corrected for heart rate by dividing by the scan heart rate and multiplying by the mean resting heart rate among all subjects. Wilcoxon matched-pairs sign rank tests were used to compare paired global and segmental perfusion values. A linear mixed-effects model with random slopes and intercepts was used to assess the relationship between baseline segmental MPR and associated change in MPR (ΔMPR) after CSR implantation. Results 12 patients (10M:2F; mean age 67) were included. Median Canadian Cardiovascular Society class was 3. Globally, there was no change in rest (P=0.90), stress MBF (P=0.34) or MPR (P=0.72) from baseline to follow-up. However, ΔMPR was related to the degree of baseline ischaemia (panel A). Segments with baseline MPR&amp;lt;2.45 increased in MPR whereas segments with baseline MPR ≥2.45 experienced a decrease (P=0.003, conditional R2: 0.81). In segments with MPR&amp;lt;2.45 (n=138), median ΔMPR was +0.18 (15.4%; P&amp;lt;0.0001); whereas with MPR≥2.45 (n=52) it was -0.41 (-12.7%; P=0.03; panel B). When assessed by myocardial layer, significant increases in MPR were observed in both subendocardial (+0.19 [15.6%]; P&amp;lt;0.0001) and subepicardial (+0.19 [12.3%]; P&amp;lt;0.0002) segments with baseline MPR&amp;lt; 2.45 (panel C). Conversely, in segments with baseline MPR≥2.45, there was a significant reduction in MPR in the subendocardium (-0.43 [-15.9%]; P=0.04) but not in the subepicardium (-0.36 [-9.90%]; P=0.08; panel D). Conclusion To our knowledge, this is the first study showing changes in quantitative myocardial perfusion after CSR implantation by fully automated inline quantitative perfusion CMR. Our analysis shows a relationship between baseline MPR and change in MPR after CSR implantation, supporting redistribution of perfusion into both subendocardial and subepicardial layers as potential mechanisms of action of CSR. Further studies are needed to confirm these preliminary results.

Fully automated quantitative stress perfusion cardiac MRI to assess myocardial perfusion in adult patients with convalescent Kawasaki disease and coronary aneurysms: an age and sex-matched analysis

Abstract Introduction Coronary aneurysms are a well-documented complication of childhood Kawasaki disease. They may persist into adulthood predisposing to impaired myocardial blood flow, symptoms, and adverse cardiovascular events. Preliminary reports suggest that Kawasaki disease may also be associated with coronary microvascular dysfunction. The effect of coronary involvement from Kawasaki disease on myocardial perfusion in convalescent asymptomatic adults has not been studied using fully automated inline quantitative perfusion MRI (CMR). Purpose To assess the effect of coronary artery abnormalities on quantitative myocardial perfusion in adult patients with convalescent Kawasaki disease compared to an age and sex-matched control cohort. Methods Retrospective single centre cohort analysis of adult patients with convalescent Kawasaki disease who have undergone fully automated inline quantitative myocardial stress perfusion CMR. All patients had coronary involvement during their acute childhood illness. An age and sex-matched group (n=14) with normal CMRs was selected for comparison. Rest MBF was corrected for heart rate by dividing by the scan heart rate and multiplying by the mean resting heart rate among all subjects. A per-vessel analysis was performed using a linear mixed effects model with pairwise comparisons to assess the effect of coronary abnormalities (normal, aneurysmal with or without thrombosis, revascularised) on myocardial perfusion reserve (MPR). Results 28 patients were included (14 Kawasaki; 14 controls). All patients in the Kawasaki cohort had assessment of coronary anatomy either by CT (93%) or invasive (7%) coronary angiography. A total of 84 vessels were analysed. Mean age and sex were well matched (Kawasaki: 27±6.2 years; 13 males : 1 female vs. controls: 27±6.4 years; 13 males : 1 female). In patients with Kawasaki disease, thrombosed aneurysmal arteries were associated with a significantly impaired MPR compared to normal (mean Δ: -0.817; P=0.003) and aneurysmal (mean Δ: -0.957; P&amp;lt;0.001) arteries. MPR in aneurysmal and revascularised arteries were not significantly different from normal arteries in patients with Kawasaki disease. There was no significant difference in MPR between normal coronary arteries in patients with Kawasaki compared to controls. Conclusions Thrombosis in coronary aneurysms was associated with a significant impairment of myocardial perfusion in adult patients with convalescent Kawasaki disease. There was no significant reduction in perfusion in territories supplied by normal or aneurysmal arteries which does not support coronary microvascular dysfunction in these patients. Further studies are needed to confirm these preliminary findings.

Abstract 11609: Developing a Novel Method for Measuring Relative Lung Perfusion at the Catheterization Laboratory

Background: Maldistribution of pulmonary blood flow (Qp) is common in patients with congenital heart disease and is associated with worse clinical outcomes. Currently, measurement of Qp-split can only be performed outside the catheterization laboratory, using either lung perfusion scans or cardiac magnetic resonance imaging. Aim: We sought to develop and evaluate a tool for measuring Qp-split using readily available fluoroscopy sequences. Methods: A retrospective cohort study of patients with conotruncal anomalies who underwent perfusion scan and subsequent cardiac catheterization. Inclusion criteria were non-selective angiogram of pulmonary vasculature, oblique angulation ≤20°, and an adequate view of both lung fields. A method was developed and implemented in 3D Slicer to calculate the amount of contrast that entered each lung field from the start of contrast-injection and until the onset of levophase. The predicted perfusion distribution was compared to the distribution measured by lung scan. Results: In total 32% (79/249) of screened studies met inclusion criteria. There was strong correlation between the predicted Qp-split and the measured Qp-split (R 2 =0.83, p&lt;0.001) with median absolute error (MAE) of 6%. Bias was not systematically worse at either extreme of flow distribution. Factors associated with better prediction were smaller BSA, younger age, right ventricle (vs. pulmonary artery) angiograms, and cranial angulations ≤20°. In cases with one or more of these conditions (n=40), the prediction achieved R 2 =0.87, MAE of 5.5%, and 78% of predictions were within 10% of true flow. Conclusions: Data from conventional angiograms can be used to provide accurate real-time measurement of relative perfusion of the left and right lungs. This has the potential to reduce unnecessary testing, associated costs, and radiation exposure.

Abstract 18068: Isometric Handgrip Exercise Myocardial Perfusion Reserve Correlates With Coronary Microvascular Dysfunction and Abnormal Left Ventricular Strain: A Report From the Women’s Ischemia Syndrome Evaluation Pre-Heart Failure With Preserved Ejection Fraction Study

Background: Impaired coronary artery response to isometric handgrip exercise (IHE) has previously been demonstrated to reflect endothelial dysfunction, an important contributor to ischemia with no obstructive coronary arteries (INOCA) and coronary microvascular dysfunction (CMD). Stress perfusion cardiac magnetic resonance (CMR) imaging is typically performed with pharmacologic stress using myocardial perfusion reserve index (MPRI) as a measure of CMD. IHE-MPRI has not been comprehensively studied in patients with INOCA, who are at risk for heart failure with preserved ejection fraction (HFpEF). Hypothesis: IHE-MPRI is related to CMD measured by pharm-MPRI and left ventricular (LV) structural and functional abnormalities in INOCA patients at risk for HFpEF. Methods: Participants with INOCA underwent comprehensive CMR with first-pass perfusion with adenosine or regadenoson, rest, and IHE. MPRI was adjusted to rest rate-pressure product (RPP). Lack of a satisfactory IHE response (defined as increase in heart rate≥10 bpm or systolic blood pressure ≥10 mmHg) was excluded. CMR measures of LV structure, function, MPRI, T1 and T2 mapping were analyzed using commercial software, blinded to clinical data. Pearson correlations were performed. Results: Of the participants (n=44) with IHE-MPRI, mean age was 55±11 years, body mass index 27±7 kg/m 2 , and 98% female, 31% hypertension, 12.5% diabetes, 19% hyperlipidemia. IHE-MPRI adjusted for rest RPP significantly correlated positively with pharm-MPRI and inversely with time to peak strain, diastolic strain measures and myocardial T2 ( Figure ). IHE-MPRI was not related to resting or IHE heart rate, systolic strain, LV mass, volumes, mass-volume ratio, native T1 or extracellular volume. Conclusion: IHE-MPRI relates to CMD and LV strain among patients with INOCA. Measurement of IHE-MPRI may improve understanding of CMD and LV structural and functional abnormalities that may contribute to development of HFpEF.

Abstract 17534: Safety and Feasibility of Adenosine Stress CMR for CAV Detection in Orthotopic Heart Transplant Recipients

Background: Stress perfusion cardiac magnetic resonance (CMR) imaging is recommended in international guidelines in class I in patients with known or suspected CAD. Patients undergoing cardiac transplantation (OHT) are at risk of developing cardiac allograft vasculopathy (CAV). Adenosine is relatively contraindicated after transplantation because of a presumed risk of atrioventricular block in denervated hearts. We sought to evaluate the safety and feasibility of adenosine stress CMR in patients with OHT and suspected CAV. Methods: In an outpatient cohort study, we measured the incidence of adverse effects of adenosine stress CMR in consecutive OHT recipients undergoing quantitative stress perfusion CMR for suspected CAV. We additionally stratified patients based on presence of significant CAV (grades 2-3 versus 0-1) on either invasive or computed tomography coronary angiography to evaluate potential CMR biomarkers of significant coronary disease in this population. Results: We identified 50 adenosine stress CMR studies performed in 45 individual patients at a median of 19 years after transplantation (IQR 4.7-24.4); 9% of studies were conducted within the first year post-transplantation. No life-threatening adverse events, brief or prolonged atrioventricular block or other arrythmias occurred after adenosine infusion. Significant myocardial ischemia (≥ 1.5 segments) was reported in 17% of patients. When stratified by CAV severity, stress MBF index, but not inducible ischemia on visual inspection, was found to significantly differentiate patients with severe CAV from those without significant coronary disease (ANOVA p = 0.028). Conclusion: Adenosine stress perfusion CMR is safe and feasible in OHT recipients. Quantitative measurement of stress MBF index may represent a promising marker of coronary disease with incremental value over qualitative assessment of ischemia, and should be evaluated in future studies.

Stress Perfusion Cardiac Magnetic Resonance vs SPECT Imaging for Detection of Coronary Artery Disease

BackgroundGadaCAD2 was 1 of 2 international, multicenter, prospective, Phase 3 clinical trials that led to U.S. Food and Drug Administration approval of gadobutrol to assess myocardial perfusion and late gadolinium enhancement (LGE) in adults with known or suspected coronary artery disease (CAD). ObjectivesA prespecified secondary objective was to determine if stress perfusion cardiovascular magnetic resonance (CMR) was noninferior to single-photon emission computed tomography (SPECT) for detecting significant CAD and for excluding significant CAD. MethodsParticipants with known or suspected CAD underwent a research rest and stress perfusion CMR that was compared with a gated SPECT performed using standard clinical protocols. For CMR, adenosine or regadenoson served as vasodilators. The total dose of gadobutrol was 0.1 mmol/kg body weight. The standard of reference was a 70% stenosis defined by quantitative coronary angiography (QCA). A negative coronary computed tomography angiography could exclude CAD. Analysis was per patient. CMR, SPECT, and QCA were evaluated by independent central core lab readers blinded to clinical information. ResultsParticipants were predominantly male (61.4% male; mean age 58.9 ± 10.2 years) and were recruited from the United States (75.0%), Australia (14.7%), Singapore (5.7%), and Canada (4.6%). The prevalence of significant CAD was 24.5% (n = 72 of 294). Stress perfusion CMR was statistically superior to gated SPECT for specificity (P = 0.002), area under the receiver operating characteristic curve (P < 0.001), accuracy (P = 0.003), positive predictive value (P < 0.001), and negative predictive value (P = 0.041). The sensitivity of CMR for a 70% QCA stenosis was noninferior and nonsuperior to gated SPECT. ConclusionsVasodilator stress perfusion CMR, as performed with gadobutrol 0.1 mmol/kg body weight, had superior diagnostic accuracy for diagnosis and exclusion of significant CAD vs gated SPECT.

Association between contrast-enhanced adenosine-stress perfusion cardiac magnetic resonance imaging and invasive coronary angiogram for the detection of coronary artery disease: A retrospective analysis.

The objective of this study was to determine the diagnostic value of stress perfusion CMR for the detection of coronary artery disease. The was a retrospective cross sectional study in which 43 subjects were included from Cardiac MRI unit in the Hayatabad Medical Complex, Peshawar for study from 1st April 2020 to 30th November 2020. All the subjects who had been referred for stress perfusion CMR with suspected CAD were included in the study. Cardiac MRI both at rest and with adenosine stress perfusion was performed which was followed by invasive coronary angiography. A total of 43 patients were enrolled for the detection or exclusion CAD who underwent stress perfusion CMRI and invasive coronary artery angiography. The study revealed strong and statistically significant association between positive stress perfusion CMR and positive coronary angiogram vs negative stress perfusion CMR and negative coronary angiogram (p= value 0.0001). Stress perfusion CMRI can be considered as a first line, relatively safe, noninvasive test with significant accuracy to diagnose coronary artery disease in patients with suspected CAD without subjecting these patients to invasive coronary angiogram.

A Hybrid Model for Cardiac Perfusion: Coupling a Discrete Coronary Arterial Tree Model with a Continuous Porous-Media Flow Model of the Myocardium.

This paper presents a novel hybrid approach for the computational modeling of cardiac perfusion, combining a discrete model of the coronary arterial tree with a continuous porous-media flow model of the myocardium. The constructive constrained optimization (CCO) algorithm captures the detailed topology and geometry of the coronary arterial tree network, while Poiseuille's law governs blood flow within this network. Contrast agent dynamics, crucial for cardiac MRI perfusion assessment, are modeled using reaction-advection-diffusion equations within the porous-media framework. The model incorporates fibrosis-contrast agent interactions and considers contrast agent recirculation to simulate myocardial infarction and Gadolinium-based late-enhancement MRI findings. Numerical experiments simulate various scenarios, including normal perfusion, endocardial ischemia resulting from stenosis, and myocardial infarction. The results demonstrate the model's efficacy in establishing the relationship between blood flow and stenosis in the coronary arterial tree and contrast agent dynamics and perfusion in the myocardial tissue. The hybrid model enables the integration of information from two different exams: computational fractional flow reserve (cFFR) measurements of the heart coronaries obtained from CT scans and heart perfusion and anatomy derived from MRI scans. The cFFR data can be integrated with the discrete arterial tree, while cardiac perfusion MRI data can be incorporated into the continuum part of the model. This integration enhances clinical understanding and treatment strategies for managing cardiovascular disease.

Comparison of phase contrast magnetic resonance imaging and scintigraphy for determination of split pulmonary blood flow in children and young adults with congenital heart disease.

Measurement of differential blood flow to the lungs is important to understanding flow dynamics in the setting of congenital heart disease. Split blood flow via the pulmonary arteries guides and demonstrates the effect of interventions. Minimally invasive imaging of pulmonary blood flow can be achieved with scintigraphy or magnetic resonance imaging (MRI). To assess agreement of pulmonary blood flow measurements obtained by scintigraphy and MRI in children and young adults. We performed a retrospective review of patients < 21years of age who had undergone both nuclear medicine pulmonary perfusion scans (Tc-99m MAA) and cardiac MRI examinations from January 2012 to August 2021 at our tertiary pediatric hospital. Patient demographics, medical/surgical information, and estimates of split blood flow by both modalities were recorded. Pearson's correlation coefficient was used to determine the relationship between split blood flow measured by the two examinations. Agreement was calculated using interclass correlation coefficient (ICC) for absolute agreement and Bland-Altman difference analysis. Correlation between split blood flow measured by scintigraphy and MRI using net flow was 0.90 (95% CI: 0.83-0.94, P< 0.001) and the ICC for agreement on split blood flow was 0.90 (95% CI: 0.84-0.94). Mean difference in split blood flow by Bland-Altman analysis was 0.79% with 95% limits of agreement (-11.2 to 12.8%). There is excellent agreement between Tc-99m scintigraphy and phase contrast MRI for quantification of split pulmonary blood flow in children and young adults with congenital heart disease.

Sex-Specific Stress Perfusion Cardiac Magnetic Resonance Imaging in Suspected Ischemic Heart Disease: Insights From SPINS Retrospective Registry

BackgroundCardiovascular disease (CVD) remains the leading cause of mortality in women, but current noninvasive cardiac imaging techniques have sex-specific limitations. ObjectivesIn this study, the authors sought to investigate the effect of sex on the prognostic utility and downstream invasive revascularization and costs of stress perfusion cardiac magnetic resonance (CMR) for suspected CVD. MethodsSex-specific prognostic performance was evaluated in a 2,349-patient multicenter SPINS (Stress CMR Perfusion Imaging in the United States [SPINS] Study) Registry. The primary outcome measure was a composite of cardiovascular death and nonfatal myocardial infarction; secondary outcomes were hospitalization for unstable angina or heart failure, and late unplanned coronary artery bypass grafting. ResultsSPINS included 1,104 women (47% of cohort); women had higher prevalence of chest pain (62% vs 50%; P < 0.0001) but lower use of medical therapies. At the 5.4-year median follow-up, women with normal stress CMR had a low annualized rate of primary composite outcome similar to men (0.54%/y vs 0.75%/y, respectively; P = NS). In contrast, women with abnormal CMR were at higher risk for both primary (3.74%/y vs 0.54%/y; P < 0.0001) and secondary (9.8%/y vs 1.6%/y; P < 0.0001) outcomes compared with women with normal CMR. Abnormal stress CMR was an independent predictor for the primary (HR: 2.64 [95% CI: 1.20-5.90]; P = 0.02) and secondary (HR: 2.09 [95% CI: 1.43-3.08]; P < 0.0001) outcome measures. There was no effect modification for sex. Women had lower rates of invasive coronary angiography (3.6% vs 7.3%; P = 0.0001) and downstream costs ($114 vs $171; P = 0.001) at 90 days following CMR. There was no effect of sex on diagnostic image quality. ConclusionsStress CMR demonstrated excellent prognostic performance with lower rates of invasive coronary angiography referral in women. Stress CMR should be considered as a first-line noninvasive imaging tool for the evaluation of women. (Stress CMR Perfusion Imaging in the United States [SPINS] Study [SPINS]; NCT03192891)

Accuracy of stress perfusion cardiac magnetic resonance imaging in a district hospital.

The European Society of Cardiology has published updated guidelines regarding pathways for diagnosis and management of obstructive coronary artery disease (CAD). Non-invasive functional assessment, for example, by stress perfusion cardiac magnetic resonance (stress pCMR) is recommended in patients with intermediate pretest probability of disease. Previous pCMR studies were mainly performed in high volume university hospitals with experienced radiologists or cardiologists interpreting the images. The aim of the present study was to evaluate the feasibility of establishing a stress pCMR imaging service in a district hospital. One hundred and thirteen patients with intermediate pretest probability of CAD referred for single-photon emission computed tomography (SPECT) at the regional hospital also underwent adenosine stress pCMR locally. The diagnostic analysis was compared to that of an experienced cardiac magnetic resonance (CMR) center serving as a reference. Inter-rater agreement between local readers and the reference reader was substantial to perfect for late gadolinium enhancement (LGE) (weighted kappa = 0.76 and 0.82), but only fair to moderate for pCMR (k = 0.34 and 0.51). No improvement in agreement between reference reader and local reader during the study was demonstrated. CMR is feasible in patients with intermediate pretest probability of obstructive CAD in the setting of a district hospital. However, as opposed to infarct detection with LGE, the interpretation of stress pCMR was more challenging. To establish this method, we suggest obtaining experience in close collaboration with a reference CMR center.

ASSESSMENT OF PATIENTS WITH KNOWN CORONARY ARTERY DISEASE BY STRESS CARDIAC MRI.

Background: Signicant coronary artery lesions can be detected by evaluating regional myocardial perfusion by Cardiac MRI (CMR). This study aims to determine the usefulness of this technique in “known” patients of coronary artery disease (CAD). Our study aims at describing CMR featur Methods: es of CAD, including CINE and perfusion imaging. Stress perfusion imaging with pharmacologic stress (Adenosine) was performed on 22 patients with known CAD. These patients also underwent Catheter angiography (CAG). A total of 66 coronary territories were assessed for perfusion abnormalities and corresponding CAG ndings. Regional wall motion abnormalities were Results: seen in 28(42.4%) coronary territories and regional myocardial thinning in 11(16%) territories. Hypokinesia (68%) was the most commonly observed wall motion abnormality. Wall motion abnormality was present in most (91%; n=20) of the infarcted territories and some (18.2%;n=8) of the non-infarct territories. Regional myocardial thinning was present in some of the infarcted (27%; n=6) territories and none of the non-infarcted territories. The mean wall thickness in infarct territories was 5.1mm±0.4 and in non-infarct territories was 7.1mm±0.6. T2/STIR hyperintensity was present in 5 (23%) infarct related coronary territories and none of the non-infarcted territories. In all 5 cases, MRI was done within 10 days of symptom onset. 32 (49%) coronary territories showed perfusion defect on stress imaging, with 23 (35%) of them showing a matched defect on rest perfusion and 9 (14%) showing stress inducible perfusion defect. No perfusion defect was seen in 34(51%) territories. All 22 patients underwent CAG. 15patients had signicant disease (&gt;70%) in a single vessel, 5 had in two vessels and none had in all the three vessels.2 patients had non-occlusive coronaries (MINOCA). Using CAG as gold standard, the sensitivity of stress perfusion CMR in detecting signicant CAD in non-infarct territory in these patients was 70%, with a specicity of 94% and accuracy of 88.3%. Visual analysis of rst-pass gadolinium CMR perfusion images to detect reg Conclusion: ional myocardial perfusion defect has a moderate sensitivity and high specicity for diagnosing signicant obstructive CAD in non-infarct related coronaries, as compared to CAG.

Adenosine triphosphate (ATP): a safe and effective vasodilator for stress perfusion cardiac magnetic resonance imaging

To evaluate the efficiency and safety of adenosine triphosphate (ATP) as a stress agent in a cohort of patients undergoing stress perfusion cardiac magnetic resonance imaging (CMRI). This retrospective study was conducted between December 2019 and October 2021. The study recruited patients who underwent stress perfusion CMRI using ATP as a vasodilator. Adverse events, such as chest pain, flushing, dyspnoea, headache, and splenic switch-off (SSO) phenomenon, were evaluated in the patients who underwent stress perfusion CMRI. The study included 107 patients (age range: 53±11 years; male:female, 62%:38%). The haemodynamic response (heart rate increased by≥10 beats/min) was quick and observed within 2 minutes of ATP infusion. Scanning was stopped in three patients because of atrioventricular block. CMRI images of seven out of 104 patients were excluded from the final analysis because of inferior quality. During ATP infusion, 37/107 patients (35%) experienced mild adverse events, such as chest pain, flushing, dyspnoea, headache, and atrioventricular block. Myocardial infarction and bronchospasms were not observed during ATP infusion. SSO, a marker of adequate stress, was observed in 91% (94/103) of the patients who underwent stress perfusion CMRI. As a coronary vasodilator, ATP was safe for stress perfusion CMRI. In addition, the adverse events during ATP infusion were mild, which were relieved within 2 minutes of ATP injection cessation. SSO could serve as an indicator of stress success in ATP stress perfusion CMRI.