Stress Cardiac Magnetic Resonance Myocardial Perfusion Imaging: JACC Review Topic of the Week

Cardiac imaging for the detection of ischemia: current status and future perspectives

INTRODUCTION

Coronary artery disease is the main cause of mortality worldwide mandating early detection, appropriate treatment, and follow-up. Noninvasive cardiac imaging techniques allow detection of obstructive coronary heart disease by direct visualization of the arteries or myocardial blood flow reduction. These techniques have made remarkable progress since their introduction, achieving high diagnostic precision. This review aims at evaluating these noninvasive cardiac imaging techniques, rendering a thorough overview of diagnostic decision-making for detection of ischemia.

AREAS COVERED

We discuss the latest advances in the field such as computed tomography angiography, single-photon emission tomography, positron emission tomography, and cardiac magnetic resonance; their main advantages and disadvantages, their most appropriate use and prospects. For the review, we analyzed the literature from 2009 to 2024 on noninvasive cardiac imaging in the diagnosis of coronary artery disease. The review included the 78 publications considered most relevant, including landmark trials, review articles and guidelines.

EXPERT OPINION

The progress in cardiac imaging is anticipated to overcome various limitations such as high costs, radiation exposure, artifacts, and differences in interpretation among observers. It is expected to lead to more automated scanning processes, and with the assistance of artificial intelligence-driven post-processing software, higher accuracy and reproducibility may be attained.

Ventricular arrhythmias in patients with chronic total occlusion of coronary arteries: a review focused on interventional treatments

A chronic total occlusion (CTO) of a coronary artery is present in almost one fifth of patients undergoing a scheduled coronary angiography. A CTO may be classified as infarct-related, when there is evidence of myocardial dysfunction on the territory of the obstructed vessel or as non-infarct related, when the myocardial substrate has preserved its systolic function. The presence of a CTO has been associated with an increased risk of malignant ventricular arrhythmias (VAs), appropriate ICD shocks and cardiac mortality with infarct related CTOs exhibiting worse prognosis. During the last decade, technological advancements have improved the success rates of transcatheter revascularization, a treatment that has been proven valuable for persistently symptomatic patients. However, the role of revascularization in reducing the arrhythmic burden is unclear. On the contrary, catheter ablation of VAs has been suggested to be effective, despite the presence of a CTO. As for device therapies, an increased prevalence of appropriate ICD shocks should be expected in this population, bringing into consideration the implementation of the presence of CTO as a risk modifier in sudden cardiac death prevention algorithms. The aim of this review is to present the existing literature on the role of all kind of interventions in the management of patients with CTOs and VAs.

Application of Myocardial Salvage Index as a Clinical Endpoint: Assessment Methods and Future Prospects

In patients with acute myocardial infarction (AMI), traditional clinical endpoints used to assess drug efficacy and prognosis include infarct size (IS), incidence of heart failure, and mortality rates. Although these metrics are commonly employed to evaluate outcomes in AMI patients, their utility is limited in small-scale studies. The introduction of the myocardial salvage index (MSI) reduces variability in assessments across multiple dimensions, thereby enhancing the sensitivity of outcome measures and reducing the required sample size. Moreover, MSI is increasingly utilized to evaluate drug efficacy, prognosis, and risk stratification in AMI patients. Although a variety of methodologies for measuring the MSI are currently available, the incorporation of these methods as clinical endpoints remains limited. In the clinical application of cardioprotective strategies, it is recommended that MSI be evaluated using late gadolinium enhancement measured along the endocardial surface length combined with IS in cardiac magnetic resonance. In dynamic single-photon emission computed tomography, an assessment of MSI using methods based on abnormalities in myocardial wall thickening combined with perfusion anomalies is advocated. This review comprehensively outlines the principles, advantages, and limitations of different MSI assessment methods and discusses the prospects and challenges of MSI in cardiac protective therapies. Additionally, we summarize recommended strategies for employing MSI as a clinical surrogate endpoint in various clinical scenarios, providing direction for future clinical practice and research. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 4.

Non-invasive imaging assessment in angina with non-obstructive coronary arteries (ANOCA)

Due to its significant prevalence and clinical implications, angina with non-obstructive coronary arteries (ANOCA) has become a major focus in modern cardiology. In fact, diagnosing ANOCA presents a significant challenge. The final diagnosis is often difficult, delayed, and frequently necessitates an invasive assessment through coronary angiography. However, recent improvements in non-invasive cardiac imaging allow a diagnosis of ANOCA using a combination of clinical evaluation, anatomical coronary imaging, and functional testing. This narrative review aims to critically assess various non-invasive diagnostic methods and propose a multimodal approach to diagnose ANOCA and tailor appropriate treatments.

Coronary Computed Angiography and Coronary Artery Calcium Score for Preoperative Cardiovascular Risk Stratification in Patients Undergoing Noncardiac Surgery

Perioperative and long-term postoperative major adverse cardiovascular events (MACE) are a leading cause of morbidity and mortality in patients undergoing noncardiac surgery. In selected high-risk patients, when information about cardiovascular status may influence surgical decisions, preoperative risk stratification is reasonable, with stress imaging being the preferred method. Coronary computed angiography (CCTA) and coronary artery calcium score (CACS) offer direct anatomical assessment of atherosclerotic coronary arteries and help gauge the extent and severity of coronary artery disease. Strong evidence supports that CCTA and CACS, either alone or in combination, are reliable methods for assessing the risk of both perioperative and long-term postoperative MACE, often demonstrating equal or superior prognostic performance compared to traditional imaging tools. Moreover, integrating CCTA or CACS into standard preoperative imaging protocols further enhances perioperative risk prediction and improves the ability to accurately stratify patients. Future research is needed to better define the role of CCTA and CACS in preoperative cardiovascular risk evaluation of patients undergoing noncardiac surgery.

Deep Learning-based Quantitative CT Myocardial Perfusion Imaging and Risk Stratification of Coronary Artery Disease

Background Precise assessment of myocardial ischemia burden and cardiovascular risk stratification based on dynamic CT myocardial perfusion imaging (MPI) is lacking. Purpose To develop and validate a deep learning (DL) model for automated quantification of myocardial blood flow (MBF) and ischemic myocardial volume (IMV) percentage and to explore the prognostic value for major adverse cardiovascular events (MACE). Materials and Methods This multicenter study comprised three cohorts of patients with clinically indicated CT MPI and coronary CT angiography (CCTA). Cohorts 1 and 2 were retrospective cohorts (May 2021 to June 2023 and January 2018 to December 2022, respectively). Cohort 3 was prospectively included (November 2016 to December 2021). The DL model was developed in cohort 1 (training set: 211 patients, validation set: 57 patients, test set: 90 patients). The diagnostic performance of MBF derived from the DL model (MBFDL) for myocardial ischemia was evaluated in cohort 2 based on the area under the receiver operating characteristic curve (AUC). The prognostic value of the DL model-derived IMV percentage was assessed in cohort 3 using multivariable Cox regression analyses. Results Across three cohorts, 1108 patients (mean age: 61 years ± 12 [SD]; 667 men) were included. MBFDL showed excellent agreement with manual measurements in the test set (segment-level intraclass correlation coefficient = 0.928; 95% CI: 0.921, 0.935). MBFDL showed higher diagnostic performance (vessel-based AUC: 0.97) over CT-derived fractional flow reserve (FFR) (vessel-based AUC: 0.87; P = .006) and CCTA-derived diameter stenosis (vessel-based AUC: 0.79; P < .001) for hemodynamically significant lesions, compared with invasive FFR. Over a mean follow-up of 39 months, MACE occurred in 94 (14.2%) of 660 patients. IMV percentage was an independent predictor of MACE (hazard ratio = 1.12, P = .003), with incremental prognostic value (C index: 0.86; 95% CI: 0.84, 0.88) over conventional risk factors and CCTA parameters (C index: 0.84; 95% CI: 0.82, 0.86; P = .02). Conclusion A DL model enabled automated CT MBF quantification and accurate diagnosis of myocardial ischemia. DL model-derived IMV percentage was an independent predictor of MACE and mildly improved cardiovascular risk stratification. © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Zhu and Xu in this issue.

Preoperative Cardiac Assessment for Coronary Artery Disease: From Symptoms to Angiography

Although cardiovascular anesthesiologists play a role in the multidisciplinary heart team, they are generally not involved prior to the diagnosis of coronary artery disease. This work was designed to broadly cover the factors influencing decision-making when proceeding with coronary angiography in a patient with suspected coronary artery disease. The authors cover the principles, rationale, benefits, and downsides of common tests involved.

Role of CT and CMR in the Management of Chronic Coronary Syndrome

Chronic coronary syndrome (CCS), encompassing a wide range of phenotypes and clinical scenarios, remains the leading global cause of disability and premature death. Advanced non-invasive imaging modalities, such as coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR), play a pivotal role in enhancing diagnostic accuracy and guiding tailored management strategies for CCS patients. CCTA offers detailed insights into the presence, extent, and severity of coronary atherosclerotic plaques. In addition to detecting coronary stenoses, it enables the characterization of plaque phenotypes and the evaluation of additional prognostic biomarkers, such as perivascular adipose tissue (PVAT) attenuation, allowing for more comprehensive risk stratification. Recent technological advancements have further expanded CCTA's capabilities, enabling the integration of anatomical assessment with hemodynamic evaluation through non-invasive fractional flow reserve computation (FFR-CT) or stress myocardial perfusion analysis. With its superior three-dimensional spatial resolution, CCTA enhances pre-procedural planning for complex coronary revascularization, enabling the selection of optimal interventional strategies and improving patient selection. CMR is considered the gold standard for functional assessment of cardiac function, myocardial viability, quantitative flow evaluation, and tissue characterization, offering excellent soft-tissue contrast. CMR perfusion imaging can accurately assess myocardial ischemia, quantify myocardial blood flow (MBF), and detect microvascular dysfunction, thanks to its high temporal and spatial resolution with the advantage of no radiation exposure. This review highlights the evolving role of CCTA and CMR in managing patients with CCS, focusing on their current applications according to the most recent 2024 ESC guidelines, prognostic value, and recent technological advancements.

Temporal Trends in Noninvasive and Invasive Cardiac Testing From 2010 to 2022 in the US Medicare Population

BACKGROUND

Cardiac diagnostic testing continues to evolve, and controversies remain regarding the optimal utilization of different procedures. We sought to evaluate changes in long-term utilization trends for a wide range of cardiac diagnostic tests in the context of advancing technologies and updated guidelines.

METHODS

Annual cardiac testing volumes from 2010 to 2022 in the Medicare Part B population were compared across tests and by provider specialty and analyzed using Joinpoint regression.

RESULTS

The most-utilized test in the Medicare population remained transthoracic echocardiography, accounting for 61.5% of cardiac testing use in 2011 and 67.7% in 2022, followed by single-photon emission computed tomography (CT) myocardial perfusion imaging, which decreased from 20.8% to 12.9%. Single-photon emission CT myocardial perfusion imaging use decreased relative to positron emission tomography myocardial perfusion imaging (ratio of 39:1 in 2011 to 7:1 in 2022), stress cardiac magnetic resonance (1179:1 in 2011, 268:1 in 2022), and coronary CT angiography (61:1 in 2011, 10:1 in 2022). Decreased use was also observed for exercise treadmill testing (2.3% to 1.7%), stress echocardiography (3.6% to 2.6%), multigated acquisition (0.4% to 0.1%), and invasive coronary angiography (8.0% to 7.0%). The use of fractional flow reserve by CT per 100 000 Medicare enrollees increased by >16-fold from 2018 (the first year covered) to 2022, and cardiac amyloidosis pyrophosphate scintigraphy studies increased 4-fold from 2011 to 2022 (0.17% to 0.68%). Positron emission tomography myocardial perfusion imaging volumes have surpassed exercise treadmill test volumes and, assuming the current rate of change continues, are projected to surpass stress echocardiography volumes in 2024. Coronary CT angiography is projected to overtake exercise treadmill testing in 2024 and stress echocardiography in 2025.

CONCLUSIONS

Between 2010 and 2022, cardiac diagnostic testing in the US Medicare population shifted from invasive angiography and traditional stress testing toward an increase in cardiac CT, cardiac magnetic resonance, and positron emission tomography. Pyrophosphate scintigraphy studies also increased, as did fractional flow reserve by CT since its introduction. Changes in preferred diagnostic modalities suggest a need to reevaluate current recommendations for training in cardiovascular medicine.

Myocardial perfusion imaging in advanced coronary artery disease

Myocardial perfusion imaging (MPI) is widely adapted as a noninvasive technique to assess the presence and extent of ischemia in patients with symptoms suggestive of obstructive coronary artery disease (CAD). However, as CAD advances, several factors can complicate the interpretation of MPI, subsequently impacting clinical decision-making. This review focuses on the utility of MPI by means of cardiac magnetic resonance (CMR) imaging, single-photon emission computed tomography (SPECT) and positron emission tomography (PET) in patients with advanced CAD-the latter characterized by documented CAD (i.e. prior myocardial infarction [MI] and/or percutaneous coronary intervention [PCI]), prior coronary artery bypass grafting (CABG) or the presence of a chronic total occlusion (CTO). It will discuss factors impacting the interpretation of MPI, the diagnostic performance for detecting obstructive CAD and coronary microvascular dysfunction (CMD), as well as the role of MPI in guiding revascularization.

Quantitative perfusion by cardiac magnetic resonance imaging reveals compromised myocardial perfusion in patients with angina with non-obstructive coronary artery disease

INTRODUCTION

Stress perfusion cardiac magnetic resonance (CMR) effectively detects myocardial ischemia. In angina with non-obstructive coronary arteries (ANOCA), visually assessed first-pass perfusion often appears normal. Automated quantitative perfusion (QP) might benefit ANOCA diagnosis, offering absolute quantification of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR).

AIM

We aimed to evaluate the efficacy of QP in detecting ANOCA.

METHODS

This study compared fully automated QP CMR in ANOCA patients with age- and sex-matched healthy controls. Participants underwent adenosine stress perfusion CMR, including visual assessment and quantification of MBF and MPR. ANOCA patients underwent coronary function testing to identify vasospasm and/or coronary microvascular dysfunction.

RESULTS

Twenty-four ANOCA patients (83% women, 57 ± 9 years) and 25 healthy controls (80% women, 56 ± 7 years) were included. Visual perfusion assessment did not differ between groups (p = 0.54). Additionally, no differences in resting MBF were observed. However, ANOCA patients had significantly lower global MBF during stress (2.43 ± 0.72 vs 2.99 ± 0.65 ml/g/min, p < 0.01) and a significantly lower global MPR (2.24 ± 0.79 vs 2.68 ± 0.64, p = 0.04) compared to healthy controls. MPR was significantly reduced in the RCA territory in ANOCA patients (2.16 ± 0.71 vs 2.69 ± 0.69, p = 0.01), with no significant differences in other coronary territories. MPR did not significantly differ between ANOCA endotypes.

CONCLUSIONS

ANOCA patients display reduced global MPR, suggesting compromised perfusion. Variation in MPR across coronary territories highlights the importance of assessing perfusion in all teritories. These findings are promising and support the use of QP for non-invasive detection of vasomotor dysfunction in ANOCA patients.

PRE-REGISTERED CLINICAL TRIAL NUMBER

The pre-registered clinical trial number is NL-OMON23861.

Exercise MR of Skeletal Muscles, the Heart, and the Brain

Magnetic resonance (MR) imaging (MRI) is routinely used to evaluate organ morphology and pathology in the human body at rest or in combination with pharmacological stress as an exercise surrogate. With MR during actual physical exercise, we can assess functional characteristics of tissues and organs under real-life stress conditions. This is particularly relevant in patients with limited exercise capacity or exercise intolerance, and where complaints typically present only during physical activity, such as in neuromuscular disorders, inherited metabolic diseases, and heart failure. This review describes practical and physiological aspects of exercise MR of skeletal muscles, the heart, and the brain. The acute effects of physical exercise on these organs are addressed in the light of various dynamic quantitative MR readouts, including phosphorus-31 MR spectroscopy (31P-MRS) of tissue energy metabolism, phase-contrast MRI of blood flow and muscle contraction, real-time cine MRI of cardiac performance, and arterial spin labeling MRI of muscle and brain perfusion. Exercise MR will help advancing our understanding of underlying mechanisms that contribute to exercise intolerance, which often proceed structural and anatomical changes in disease. Its potential to detect disease-driven alterations in organ function, perfusion, and metabolism under physiological stress renders exercise MR stress testing a powerful noninvasive imaging modality to aid in disease diagnosis and risk stratification. Although not yet integrated in most clinical workflows, and while some applications still require thorough validation, exercise MR has established itself as a comprehensive and versatile modality for characterizing physiology in health and disease in a noninvasive and quantitative way. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 1.

Coronary Microvascular Function in Asymptomatic Middle-Aged Individuals With Cardiometabolic Risk Factors

BACKGROUND

In patients with ischemic heart disease, coronary microvascular dysfunction is associated with cardiovascular risk factors and poor prognosis; however, data from healthy individuals are scarce.

OBJECTIVES

The purpose of this study was to assess the impact of cardiovascular risk factors and subclinical atherosclerosis on coronary microvascular function in middle-aged asymptomatic individuals.

METHODS

Myocardial perfusion was measured at rest and under stress using cardiac magnetic resonance in 453 individuals and used to generate myocardial blood flow (MBF) maps and calculate myocardial perfusion reserve (MPR). Subclinical atherosclerosis was assessed using 3-dimensional vascular ultrasound of the carotid and femoral arteries and coronary artery calcium scoring at baseline and at 3-year follow-up.

RESULTS

Median participant age was 52.6 years (range: 48.9-55.8 years), and 84.5% were male. After adjusting for age and sex, rest MBF was directly associated with the number of the metabolic syndrome components present (elevated waist circumference, systolic and diastolic blood pressure, fasting glucose, and triglycerides and low high-density lipoprotein cholesterol), insulin resistance (homeostatic model assessment for insulin resistance), and presence of diabetes. MPR was reduced in the presence of several metabolic syndrome components, elevated homeostatic model assessment for insulin resistance, and diabetes. Stress MBF was inversely associated with coronary artery calcium presence and with global plaque burden. Higher stress MBF and MPR were associated with less atherosclerosis progression (increase in plaque volume) at 3 years.

CONCLUSIONS

In asymptomatic middle-aged individuals free of known cardiovascular disease, the presence of cardiometabolic risk factors and systemic (poly-vascular) subclinical atherosclerosis are associated with impaired coronary microvascular function. Better coronary microvascular function reduces atherosclerosis progression at follow-up. (Progression of Early Subclinical Atherosclerosis [PESA]; NCT01410318).

Artifacts at Cardiac MRI: Imaging Appearances and Solutions

Cardiac MRI (CMR) is an important imaging modality in the evaluation of cardiovascular diseases. CMR image acquisition is technically challenging, which in some circumstances is associated with artifacts, both general as well as sequence specific. Recognizing imaging artifacts, understanding their causes, and applying effective approaches for artifact mitigation are critical for successful CMR. Balanced steady-state free precession (bSSFP), the most common CMR sequence, is associated with band and flow artifacts, which are amplified at 3-T imaging. This can be mitigated by targeted shimming, by short repetition time, or by using a frequency-scout sequence. In patients with cardiac arrhythmias or poor breath hold, the quality of cine imaging can be improved with a non-electrocardiographically gated free-breathing real-time sequence. Motion artifacts on late gadolinium enhancement (LGE) images can be mitigated by using single-shot technique with motion compensation and signal averaging. LGE images are also prone to partial-volume averaging and incomplete myocardial nulling. In phase-contrast imaging, aliasing artifact is seen when the velocity of blood is higher than the encoded velocity. Aliasing can be mitigated by increasing the encoded velocity or using postprocessing software. In first-pass perfusion imaging, a dark rim artifact due to Gibbs ringing can be distinguished from a true perfusion defect based on earlier appearance and fading after a few cardiac cycles. With implanted cardiac devices, artifactual high signal intensity mimicking scar is seen on LGE images, which can be mitigated using a wide-band sequence. With devices and metallic artifacts, traditional gradient-recalled echo sequence has fewer artifacts than bSSFP. CMR at 3 T requires adaptation of sequences to minimize artifacts. ©RSNA, 2025 Supplemental material is available for this article.

Evaluation of myocardial perfusion imaging techniques and artificial intelligence (AI) tools in coronary artery disease (CAD) diagnosis through multi-criteria decision-making method

Background

Cardiovascular diseases (CVDs) continue to be the world's greatest cause of death. To evaluate heart function and diagnose coronary artery disease (CAD), myocardial perfusion imaging (MPI) has become essential. Artificial intelligence (AI) methods have been incorporated into diagnostic methods such as MPI to improve patient outcomes in recent years. This study aims to employ a novel approach to examine how parameters/criteria and performance metrics affect the prioritization of selected MPI techniques and AI tools in CAD diagnosis. Identifying the most effective method in these two interconnected areas will increase the CAD diagnosis rate.

Methods

The study includes an in-depth investigation of popular convolutional neural network (CNN) models, including InceptionV3, VGG16, ResNet50, and DenseNet121, in addition to widely used machine learning (ML) models, including random forests (RF), K-nearest neighbor (KNN), support vector machine (SVM), and Naïve Bayes (NB). In addition, it includes the evaluation of nuclear MPI techniques, including positron emission tomography (PET) and single photon emission computed tomography (SPECT), with the non-nuclear MPI technique of cardiovascular magnetic resonance imaging (CMR). Various performance metrics were used to evaluate AI tools. They are F1-score, recall, specificity, precision, accuracy, and area under the receiver operating characteristic curve (AUC-ROC). For MPI techniques, the evaluation criteria include specificity, sensitivity, radiation dose, cost of scan, and study duration. The analysis was evaluated and compared using the fuzzy-based preference ranking organization method for enrichment evaluation (PROMETHEE), the multi-criteria decision-making method (MDCM).

Results

According to the study's findings, considering selected performance metrics or criteria, RF is the most efficient AI tool for SPECT MPI in the diagnosis of CAD with a net flow (Φnet ) of 0.3778, and it's revealed that CMR is the most efficient MPI technique for CAD diagnosis with a net flow of 0.3666. By expanding this study, more comprehensive evaluations can be made in the diagnosis of CAD.

Conclusions

It was concluded that CMR outperformed the nuclear MPI techniques. SPECT, as the least advantageous technique, remained below average on other criteria except for the cost of the scan. Integrating the RF algorithm, which stands out as the most effective AI tool in diagnosing CAD, with SPECT MPI may contribute to SPECT becoming a superior alternative.

Myocardial Blood Flow Quantification Using Stress Cardiac Magnetic Resonance Improves Detection of Coronary Artery Disease

BACKGROUND

Myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) using stress cardiovascular magnetic resonance (CMR) have been shown to identify epicardial coronary artery disease. However, comparative analysis between quantitative perfusion and conventional qualitative assessment (QA) remains limited.

OBJECTIVES

The aim of this multicenter study was to test the hypothesis that quantitative stress MBF (sMBF) and MPR analysis can identify obstructive coronary artery disease (obCAD) with comparable performance as QA of stress CMR performed by experienced physicians in interpretation.

METHODS

The analysis included 127 individuals (mean age 62 ± 16 years, 84 men [67%]) who underwent stress CMR. obCAD was defined as the presence of stenosis ≥50% in the left main coronary artery or ≥70% in a major vessel. Each patient, coronary territory, and myocardial segment was categorized as having either obCAD or no obCAD (noCAD). Global, per coronary territory, and segmental MBF and MPR values were calculated. QA was performed by 4 CMR experts.

RESULTS

At the patient level, global sMBF and MPR were significantly lower in subjects with obCAD than in those with noCAD, with median values of sMBF of 1.5 mL/g/min (Q1-Q3: 1.2-1.8 mL/g/min) vs 2.4 mL/g/min (Q1-Q3: 2.1-2.7 mL/g/min) (P < 0.001) and median values of MPR of 1.3 (Q1-Q3: 1.0-1.6) vs 2.1 (Q1-Q3: 1.6-2.7) (P < 0.001). At the coronary artery level, sMBF and MPR were also significantly lower in vessels with obCAD compared with those with noCAD. Global sMBF and MPR had areas under the curve (AUCs) of 0.90 (95% CI: 0.84-0.96) and 0.86 (95% CI: 0.80-0.93). The AUCs for QA by 4 physicians ranged between 0.69 and 0.88. The AUC for global sMBF and MPR was significantly better than the average AUC for QA.

CONCLUSIONS

This study demonstrates that sMBF and MPR using dual-sequence stress CMR can identify obCAD more accurately than qualitative analysis by experienced CMR readers.

Coronary Microvascular Dysfunction and Diffuse Myocardial Fibrosis in Patients With Type 2 Diabetes Using Quantitative Perfusion MRI

BACKGROUND

Imaging techniques that quantitatively and automatically measure changes in the myocardial microcirculation in patients with diabetes are lacking.

PURPOSE

To detect diabetic myocardial microvascular complications using a novel automatic quantitative perfusion MRI technique, and to explore the relationship between myocardial microcirculation dysfunction and fibrosis.

STUDY TYPE

Prospective.

SUBJECTS

101 patients with type 2 diabetes mellitus (T2DM) (53 without and 48 with complications), 20 healthy volunteers.

FIELD STRENGTH/SEQUENCE

3.0T; modified Look-Locker inversion-recovery sequence; saturation recovery sequence and dual-bolus technique; segmented fast low-angle shot sequence.

ASSESSMENT

All participants underwent MRI to determine the rest myocardial blood flow (MBF), stress MBF, myocardial perfusion reserve (MPR), and extracellular volume (ECV), which represents the extent of myocardial fibrosis.

STATISTICAL TESTS

Kolmogorov-Smirnov test, Shapiro-Wilk test, Kruskal-Wallis H test, Mann-Whitney U test, chi-square test, Spearman correlation coefficient, multivariable linear regression analysis. P < 0.05 was considered statistically significant.

RESULTS

The rest MBF was not significantly different between the T2DM without complications group (1.1, IQR: 0.9-1.3) and the control group (1.1, 1.0-1.3) (P = 1.000), but it was significantly lower in the T2DM with complications group (0.8, 0.6-1.0) than in both other groups. The stress MBF and MPR were significantly lower in the T2DM without complications group (1.9, 1.5-2.3, and 1.7, 1.4-2.1, respectively) than in the control group (3.0, 2.6-3.5, and 2.7, 2.4-3.1, respectively), and were also significantly lower in the T2DM with complications group (1.1, 0.9-1.4, and 1.4, 1.2-1.8, respectively) than in the T2DM without complications group. A decrease in MBF and MPR were significantly associated with an increase in the ECV.

DATA CONCLUSION

Quantitative perfusion MRI can evaluate myocardial microcirculation dysfunction. In T2DM, there was a significant decrease in both MBF and MPR compared to healthy controls, with the decrease being significantly different between T2DM with and without complications groups. The decrease of MBF was significantly associated with the development of myocardial fibrosis, as determined by ECV.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 3.

Cardiac MRI in Rheumatic Disease

Immune-mediated systemic inflammatory disorders present a latent threat for cardiovascular disease. Early involvement may be associated with constitutional symptoms, while clinical evidence of disease may manifest later in an insidious manner. Multimodality imaging is crucial to detect myocardial involvement, with transthoracic echocardiogram as a first-line imaging modality; however, cardiac MRI (CMRI) has the potential to significantly impact our diagnostic and therapeutic approaches through high-fidelity chamber quantification and parametric mapping techniques. Novel imaging techniques are currently under investigation, including stress CMRI, feature tracking CMR, late gadolinium enhancement (LGE) entropy, and 4 dimensional flow CMRI.

Polymorphic Ventricular Tachycardia Associated with Coronary Vasospasm in a Patient with Coronavirus Disease 2019 Infection

A 70-year-old man was admitted to our hospital for restoration of sinus rhythm from atrial fibrillation by direct current counter shocks. On admission, he had a coronavirus disease 2019 (COVID-19) infection and syncope during bed rest. Electrocardiography revealed polymorphic ventricular tachycardia after ST-segment elevation with a normal QT interval. Coronary angiography revealed coronary vasospasm. Coronary vasospasm may be a cause of polymorphic ventricular tachycardia in COVID-19 patients.

Prognostic value of stress perfusion cardiac magnetic resonance in patients with prediabetes and suspected coronary artery disease

BACKGROUND

Stress perfusion cardiac magnetic resonance (CMR) is an accurate and comprehensive modality for evaluating patients with suspected coronary artery disease (CAD), but its prognostic value in prediabetic patients is uncertain.

METHODS

This retrospective study included 452 consecutive prediabetic patients without prior diagnoses of CAD who underwent adenosine stress perfusion CMR. The primary endpoint was major adverse cardiovascular events (MACE), defined as cardiovascular death, nonfatal myocardial infarction (MI), hospitalization for heart failure, ischemic stroke, and late coronary revascularization (>90 days post-CMR). The secondary endpoint was a composite of cardiovascular death, nonfatal MI, and hospitalization for heart failure.

RESULTS

The mean age was 68±11 years (49% male). Over a median follow-up time of 8.1 (IQR 5.7, 10.4) years, 55 patients experienced MACE, and 24 met the secondary endpoint. Patients with inducible ischemia had significantly greater annualized event rates for MACE (5.7% vs. 0.7%, p<0.001) and for the secondary endpoint (2.0% vs. 0.3%, p<0.001) than those without ischemia. Multivariable analysis revealed inducible ischemia as a consistent predictor for MACE (HR 3.36, 95%CI 1.90-5.94, p<0.001) and for the secondary endpoint (HR 2.89, 95%CI 1.22-6.80, p = 0.01). Late gadolinium enhancement (LGE) was an independent predictor of the secondary endpoint (HR 3.56, 95%CI 1.25-10.13; p = 0.02). Incorporating inducible ischemia and LGE data significantly improved the model's ability to discriminate MACE risk (C-statistic increase from 0.77 to 0.83; net reclassification improvement 0.42; integrated discrimination improvement 0.05).

CONCLUSION

Stress perfusion CMR offers substantial independent prognostic value and effectively aids in reclassifying cardiovascular risk among prediabetic patients with suspected CAD.

Comparison of Myocardial Blood Flow Quantification Models for Double ECG Gating Arterial Spin Labeling MRI: Reproducibility Assessment

BACKGROUND

Arterial spin labeling (ASL) allows non-invasive quantification of myocardial blood flow (MBF). Double-ECG gating (DG) ASL is more robust to heart rate variability than single-ECG gating (SG), but its reproducibility requires further investigation. Moreover, the existence of multiple quantification models hinders its application. Frequency-offset-corrected-inversion (FOCI) pulses provide sharper edge profiles than hyperbolic-secant (HS), which could benefit myocardial ASL.

PURPOSE

To assess the performance of MBF quantification models for DG compared to SG ASL, to evaluate their reproducibility and to compare the effects of HS and FOCI pulses.

STUDY TYPE

Prospective.

SUBJECTS

Sixteen subjects (27 ± 8 years).

FIELD STRENGTH/SEQUENCE

1.5 T/DG and SG flow-sensitive alternating inversion recovery ASL.

ASSESSMENT

Three models for DG MBF quantification were compared using Monte Carlo simulations and in vivo experiments. Two models used a fitting approach (one using only a single label and control image pair per fit, the other using all available image pairs), while the third model used a T1 correction approach. Slice profile simulations were conducted for HS and FOCI pulses with varying B0 and B1. Temporal signal-to-noise ratio (tSNR) was computed for different acquisition/quantification strategies and inversion pulses. The number of images that minimized MBF error was investigated in the model with highest tSNR. Intra and intersession reproducibility were assessed in 10 subjects.

STATISTICAL TESTS

Within-subject coefficient of variation, analysis of variance. P-value <0.05 was considered significant.

RESULTS

MBF was not different across acquisition/quantification strategies (P = 0.27) nor pulses (P = 0.9). DG MBF quantification models exhibited significantly higher tSNR and superior reproducibility, particularly for the fitting model using multiple images (tSNR was 3.46 ± 2.18 in vivo and 3.32 ± 1.16 in simulations, respectively; wsCV = 16%). Reducing the number of ASL pairs to 13/15 did not increase MBF error (minimum = 0.22 mL/g/min).

DATA CONCLUSION

Reproducibility of MBF was better for DG than SG acquisitions, especially when employing a fitting model.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 1.

Ischemia with non-obstructive coronary artery (INOCA): Non-invasive versus invasive techniques for diagnosis and the role of #FullPhysiology

Ischemia with non-obstructive coronary arteries (INOCA) is an increasingly recognized entity. It encompasses different pathophysiological subtypes (i.e., endotypes), including coronary microvascular dysfunction (CMD), vasospastic angina (VSA) and mixed entities resulting from the variable combination of both. Diagnosing INOCA and precisely characterizing the endotype allows for accurate medical treatment and has proven prognostic implications. A breadth of diagnostic technique is available, ranging from non-invasive approaches to invasive coronary angiography adjuvated by functional assessment and provocative tests. This review summarizes the strength and limitations of these methodologies and provides the rationale for the routine referral for invasive angiography and functional assessment in this subset of patients.

A Comprehensive Review of Cardiovascular Disease Management: Cardiac Biomarkers, Imaging Modalities, Pharmacotherapy, Surgical Interventions, and Herbal Remedies

Cardiovascular diseases (CVDs) continue to be a major global health concern, representing a leading cause of morbidity and mortality. This review provides a comprehensive examination of CVDs, encompassing their pathophysiology, diagnostic biomarkers, advanced imaging techniques, pharmacological treatments, surgical interventions, and the emerging role of herbal remedies. The review covers various cardiovascular conditions such as coronary artery disease, atherosclerosis, peripheral artery disease, deep vein thrombosis, pulmonary embolism, cardiomyopathy, rheumatic heart disease, hypertension, ischemic heart disease, heart failure, cerebrovascular diseases, and congenital heart defects. The review presents a wide range of cardiac biomarkers such as troponins, C-reactive protein, CKMB, BNP, NT-proBNP, galectin, adiponectin, IL-6, TNF-α, miRNAs, and oxylipins. Advanced molecular imaging techniques, including chest X-ray, ECG, ultrasound, CT, SPECT, PET, and MRI, have significantly enhanced our ability to visualize myocardial perfusion, plaque characterization, and cardiac function. Various synthetic drugs including statins, ACE inhibitors, ARBs, β-blockers, calcium channel blockers, antihypertensives, anticoagulants, and antiarrhythmics are fundamental in managing CVDs. Nonetheless, their side effects such as hepatic dysfunction, renal impairment, and bleeding risks necessitate careful monitoring and personalized treatment strategies. In addition to conventional therapies, herbal remedies have garnered attention for their potential cardiovascular benefits. Plant extracts and their bioactive compounds, such as flavonoids, phenolic acids, saponins, and alkaloids, offer promising cardioprotective effects and enhanced cardiovascular health. This review underscores the value of combining traditional and modern therapeutic approaches to improve cardiovascular outcomes. This review serves as a vital resource for researchers by integrating a broad spectrum of information on CVDs, diagnostic tools, imaging techniques, pharmacological treatments and their side effects, and the potential of herbal remedies.

Next-Generation Cardiac Magnetic Resonance Imaging Techniques for Characterization of Myocardial Disease

Purpose of the Review

Many novel cardiac magnetic resonance imaging (cMR) techniques have been developed for diagnosis, risk stratification, and monitoring of myocardial disease. The field is changing rapidly with advances in imaging technology. The purpose of this review is to give an update on next-generation cMR techniques with promising developments for clinical translation in the last two years, and to outline clinical applications.

Recent Findings

There has been increasing widespread clinical adoption of T1/T2 mapping into standard of care clinical practice. Development of auto segmentation has enabled clinical integration, with potential applications to minimize the use of contrast. Advances in diffusion tensor imaging, multiparametric mapping with cardiac MRI fingerprinting, automated quantitative perfusion mapping, metabolic imaging, elastography, and 4D flow are advancing the ability of cMR to provide further quantitative characterization to enable deep myocardial disease phenotyping. Together these advanced imaging features further augment the ability of cMR to contribute to novel disease characterization and may provide an important platform for personalized medicine.

Summary

Next-generation cMR techniques provide unique quantitative imaging features that can enable the identification of imaging biomarkers that may further refine disease classification and risk prediction. However, widespread clinical application continues to be limited by ground truth validation, reproducibility of the techniques across vendor platforms, increased scan time, and lack of widespread availability of advanced cardiac MRI physicists and expert readers. However, these techniques show great promise in minimizing the need for invasive testing, may elucidate novel pathophysiology, and may provide the ability for more accurate diagnosis of myocardial disease.

Advances in Surgical Treatments of Left Ventricular Aneurysms

Despite improvements in the early intervention of myocardial infarction (MI) in recent decades, left ventricular aneurysms (LVA) remain a major health concern, particularly in developing nations. The progression of MI can lead to the thinning of the myocardial wall and the formation of a ventricular wall bulge, characteristic of an LVA. Furthermore, cardiac magnetic resonance (CMR) has emerged as the gold standard for LVA diagnosis due to its superior imaging capabilities. Notably, surgical ventricular reconstruction (SVR) is an effective treatment for LVA, aiming to restore the normal volume and structure of the left ventricle, thereby improving cardiac function. However, the criteria for selecting patients for SVR treatment remains a subject of debate. This review focuses on the current understanding of surgical indications, procedures, and prognostic risk factors that influence outcomes in left ventricular reconstruction, highlighting the need for precise patient selection to optimize surgical benefits.

MRI of cardiac involvement in COVID-19

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has led to a diverse pattern of myocardial injuries, including myocarditis, which is linked to adverse outcomes in patients. Research indicates that myocardial injury is associated with higher mortality in hospitalized severe COVID-19 patients (75.8% vs 9.7%). Cardiovascular Magnetic Resonance (CMR) has emerged as a crucial tool in diagnosing both ischaemic and non-ischaemic myocardial injuries, providing detailed insights into the impact of COVID-19 on myocardial tissue and function. This review synthesizes existing studies on the histopathological findings and CMR imaging patterns of myocardial injuries in COVID-19 patients. CMR imaging has revealed a complex pattern of cardiac damage in these patients, including myocardial inflammation, oedema, fibrosis, and ischaemic injury, due to coronary microthrombi. This review also highlights the role of LLC criteria in diagnosis of COVID-related myocarditis and the importance of CMR in detecting cardiac complications of COVID-19 in specific groups, such as children, manifesting multisystem inflammatory syndrome in children (MIS-C) and athletes, as well as myocardial injuries post-COVID-19 infection or following COVID-19 vaccination. By summarizing existing studies on CMR in COVID-19 patients and highlighting ongoing research, this review contributes to a deeper understanding of the cardiac impacts of COVID-19. It emphasizes the effectiveness of CMR in assessing a broad spectrum of myocardial injuries, thereby enhancing the management and prognosis of patients with COVID-19 related cardiac complications.

Association of Adverse Clinical Outcomes With Peri-Infarct Ischemia Detected by Stress Cardiac Magnetic Imaging

BACKGROUND

Early invasive revascularization guided by moderate to severe ischemia did not improve outcomes over medical therapy alone, underlying the need to identify high-risk patients for a more effective invasive referral. CMR could determine the myocardial extent and matching locations of ischemia and infarction.

OBJECTIVES

This study sought to investigate if CMR peri-infarct ischemia is associated with adverse events incremental to known risk markers.

METHODS

Consecutive patients were included in an expanded cohort of the multicenter SPINS (Stress CMR Perfusion Imaging in the United States) study. Peri-infarct ischemia was defined by the presence of any ischemic segment neighboring an infarcted segment by late gadolinium enhancement imaging. Primary outcome events included acute myocardial infarction and cardiovascular death, whereas secondary events included any primary events, hospitalization for unstable angina, heart failure hospitalization, and late coronary artery bypass surgery.

RESULTS

Among 3,915 patients (age: 61.0 ± 12.9 years; 54.7% male), ischemia, infarct, and peri-infarct ischemia were present in 752 (19.2%), 1,123 (28.8%), and 382 (9.8%) patients, respectively. At 5.3 years (Q1-Q3: 3.9-7.2 years) of median follow-up, primary and secondary events occurred in 406 (10.4%) and 745 (19.0%) patients, respectively. Peri-infarct ischemia was the strongest multivariable predictor for primary and secondary events (HRadjusted: 1.72 [95% CI: 1.23-2.41] and 1.71 [95% CI: 1.32-2.20], respectively; both P < 0.001), adjusted for clinical risk factors, left ventricular function, ischemia extent, and infarct size. The presence of peri-infarct ischemia portended to a >6-fold increased annualized primary event rate compared to those with no infarct and ischemia (6.5% vs 0.9%).

CONCLUSIONS

Peri-infarct ischemia is a novel and robust prognostic marker of adverse cardiovascular events.

Efficacy of Diagnostic Testing of Suspected Coronary Artery Disease: A Contemporary Review

BACKGROUND

Coronary artery disease (CAD) is a highly prevalent condition which can lead to myocardial ischemia as well as acute coronary syndrome. Early diagnosis of CAD can improve patient outcomes through guiding risk factor modification and treatment modalities.

SUMMARY

Testing for CAD comes with increased cost and risk; therefore, physicians must determine which patients require testing, and what testing modality will offer the most useful data to diagnose patients with CAD. Patients should have an initial risk stratification for pretest probability of CAD based on symptoms and available clinical data. Patients with a pretest probability less than 5% should receive no further testing, while patients with a high pretest probability should be considered for direct invasive coronary angiography. In patients with a pretest probability between 5 and 15%, coronary artery calcium score and or exercise electrocardiogram can be obtained to further risk stratify patients to low-risk versus intermediate-high-risk. Intermediate-high-risk patients should be tested with coronary computed tomography angiography (preferred) versus positron emission tomography or single photon emission computed tomography based on their individual patient characteristics and institutional availability.

KEY MESSAGES

This comprehensive review aimed to describe the available CAD testing modalities, detail their risks and benefits, and propose when each should be considered in the evaluation of a patient with suspected CAD.

BACKGROUND

Coronary artery disease (CAD) is a highly prevalent condition which can lead to myocardial ischemia as well as acute coronary syndrome. Early diagnosis of CAD can improve patient outcomes through guiding risk factor modification and treatment modalities.

SUMMARY

Testing for CAD comes with increased cost and risk; therefore, physicians must determine which patients require testing, and what testing modality will offer the most useful data to diagnose patients with CAD. Patients should have an initial risk stratification for pretest probability of CAD based on symptoms and available clinical data. Patients with a pretest probability less than 5% should receive no further testing, while patients with a high pretest probability should be considered for direct invasive coronary angiography. In patients with a pretest probability between 5 and 15%, coronary artery calcium score and or exercise electrocardiogram can be obtained to further risk stratify patients to low-risk versus intermediate-high-risk. Intermediate-high-risk patients should be tested with coronary computed tomography angiography (preferred) versus positron emission tomography or single photon emission computed tomography based on their individual patient characteristics and institutional availability.

KEY MESSAGES

This comprehensive review aimed to describe the available CAD testing modalities, detail their risks and benefits, and propose when each should be considered in the evaluation of a patient with suspected CAD.

Which Test Should I Order for an Inpatient Evaluation of Cardiac Ischemia?

AbstractTesting for cardiac ischemia, or for the obstructive coronary artery disease (CAD) that causes cardiac ischemia, is common among hospitalized patients. Many testing options exist. Choosing an appropriate test can be challenging and requires accurate risk stratification. Two major categories of testing are available: stress testing (also known as functional testing) and anatomical testing. Stress testing evaluates specifically for ischemia and can be conducted with or without imaging. Anatomical testing visualizes the obstructive CAD that causes ischemia. This article reviews how to choose an appropriate test for the evaluation of cardiac ischemia in the inpatient setting, using case examples to illustrate the considerations involved.

Clinical impact of multimodality assessment of myocardial viability

Coronary artery disease (CAD) is a prevalent cause of left ventricular dysfunction. Nevertheless, effective elective revascularization, particularly surgical revascularization, can enhance long-term outcomes and, in selected cases, global left ventricular contractility. The assessment of myocardial viability and scars is still relevant in guiding treatment decisions and selecting patients who are likely to benefit most from blood flow restoration. Although the most recent randomized studies challenge the notion of "hibernating myocardium" and the clinical usefulness of assessing myocardial viability, the advancement of imaging techniques still renders this assessment valuable in specific situations. According to the guidelines of the European Society of Cardiology, non-invasive stress imaging may be employed to define myocardial ischemia and viability in patients with CAD and heart failure before revascularization. Currently, several non-invasive imaging techniques are available to evaluate the presence and extent of viable myocardium. The selection of the most suitable technique should be based on the patient, clinical context, and resource availability. This narrative review evaluates the characteristics of available imaging modalities for assessing myocardial viability to determine the most appropriate therapeutic strategy.

Personalized brain circuit scores identify clinically distinct biotypes in depression and anxiety

There is an urgent need to derive quantitative measures based on coherent neurobiological dysfunctions or 'biotypes' to enable stratification of patients with depression and anxiety. We used task-free and task-evoked data from a standardized functional magnetic resonance imaging protocol conducted across multiple studies in patients with depression and anxiety when treatment free (n = 801) and after randomization to pharmacotherapy or behavioral therapy (n = 250). From these patients, we derived personalized and interpretable scores of brain circuit dysfunction grounded in a theoretical taxonomy. Participants were subdivided into six biotypes defined by distinct profiles of intrinsic task-free functional connectivity within the default mode, salience and frontoparietal attention circuits, and of activation and connectivity within frontal and subcortical regions elicited by emotional and cognitive tasks. The six biotypes showed consistency with our theoretical taxonomy and were distinguished by symptoms, behavioral performance on general and emotional cognitive computerized tests, and response to pharmacotherapy as well as behavioral therapy. Our results provide a new, theory-driven, clinically validated and interpretable quantitative method to parse the biological heterogeneity of depression and anxiety. Thus, they represent a promising approach to advance precision clinical care in psychiatry.

Imaging approaches in risk stratification of patients with coronary artery disease: a narrative review

Coronary artery disease (CAD) is the most common cause of mortality among adults worldwide. In the prognostic risk stratification of these patients, crucial determinants are lumen stenosis, total volume and composition of the plaque. Considering that most of the myocardial infarctions are due to non-obstructive plaques or are associated with high-risk features, plaque composition can serve as an independent predictor of cardiac outcomes. Conversely, although there is a close relationship between ischemia and CAD severity, the assessment of the degree of ischemia, as a surrogate marker of the coronary plaque burden, remains a controversial issue. Thus, aim of this narrative review is to discuss the usefulness of the imaging methodologies to differentiate the ischemia vs the plaque burden in clinical practice. New diagnostic tools to evaluate the extent of the atheromatous coronary artery could help in tailoring a personalized therapeutic approach.

Prognostic Value of Stress Perfusion Cardiac MRI in Cardiovascular Disease: A Systematic Review and Meta-Analysis of the Effects of the Scanner, Stress Agent, and Analysis Technique

Purpose To perform a systematic review and meta-analysis to assess the prognostic value of stress perfusion cardiac MRI in predicting cardiovascular outcomes. Materials and Methods A systematic literature search from the inception of PubMed, Embase, Web of Science, and China National Knowledge Infrastructure until January 2023 was performed for articles that reported the prognosis of stress perfusion cardiac MRI in predicting cardiovascular outcomes. The quality of included studies was assessed using the Quality in Prognosis Studies tool. Reported hazard ratios (HRs) of univariable regression analyses with 95% CIs were pooled. Comparisons were performed across different analysis techniques (qualitative, semiquantitative, and fully quantitative), magnetic field strengths (1.5 T vs 3 T), and stress agents (dobutamine, adenosine, and dipyridamole). Results Thirty-eight studies with 58 774 patients with a mean follow-up time of 53 months were included. There were 1.9 all-cause deaths and 3.5 major adverse cardiovascular events (MACE) per 100 patient-years. Stress-inducible ischemia was associated with a higher risk of all-cause mortality (HR: 2.55 [95% CI: 1.89, 3.43]) and MACE (HR: 3.90 [95% CI: 2.69, 5.66]). For MACE, pooled HRs of qualitative, semiquantitative, and fully quantitative methods were 4.56 (95% CI: 2.88, 7.22), 3.22 (95% CI: 1.60, 6.48), and 1.78 (95% CI: 1.39, 2.28), respectively. For all-cause mortality, there was no evidence of a difference between qualitative and fully quantitative methods (P = .79). Abnormal stress perfusion cardiac MRI findings remained prognostic when subgrouped based on underlying disease, stress agent, and field strength, with HRs of 3.54, 2.20, and 3.38, respectively, for all-cause mortality and 3.98, 3.56, and 4.21, respectively, for MACE. There was no evidence of subgroup differences in prognosis between field strengths or stress agents. There was significant heterogeneity in effect size for MACE outcomes in the subgroups assessing qualitative versus quantitative stress perfusion analysis, underlying disease, and field strength. Conclusion Stress perfusion cardiac MRI is valuable for predicting cardiovascular outcomes, regardless of the analysis method, stress agent, or magnetic field strength used. Keywords: MR-Perfusion, MRI, Cardiac, Meta-Analysis, Stress Perfusion, Cardiac MR, Cardiovascular Disease, Prognosis, Quantitative © RSNA, 2024 Supplemental material is available for this article.

Equilibrium phase contrast-enhanced magnetic resonance angiography of the thoracic aorta and heart using balanced T1 relaxation-enhanced steady-state

BACKGROUND

Three-dimensional (3D) contrast-enhanced magnetic resonance angiography (CEMRA) is routinely used for vascular evaluation. With existing techniques for CEMRA, diagnostic image quality is only obtained during the first pass of the contrast agent or shortly thereafter, whereas angiographic quality tends to be poor when imaging is delayed to the equilibrium phase. We hypothesized that prolonged blood pool contrast enhancement could be obtained by imaging with a balanced T1 relaxation-enhanced steady-state (bT1RESS) pulse sequence, which combines 3D balanced steady-state free precession (bSSFP) with a saturation recovery magnetization preparation to impart T1 weighting and suppress background tissues. An electrocardiographic-gated, two-dimensional-accelerated version with isotropic 1.1-mm spatial resolution was evaluated for breath-hold equilibrium phase CEMRA of the thoracic aorta and heart.

METHODS

The study was approved by the institutional review board. Twenty-one subjects were imaged using unenhanced 3D bSSFP, time-resolved CEMRA, first-pass gated CEMRA, followed by early and late equilibrium phase gated CEMRA and bT1RESS. Nine additional subjects were imaged using equilibrium phase 3D bSSFP and bT1RESS. Images were evaluated for image quality, aortic root sharpness, and visualization of the coronary artery origins, as well as using standard quantitative measures.

RESULTS

Equilibrium phase bT1RESS provided better image quality, aortic root sharpness, and coronary artery origin visualization than gated CEMRA (P < 0.05), and improved image quality and aortic root sharpness versus unenhanced 3D bSSFP (P < 0.05). It provided significantly larger apparent signal-to-noise and apparent contrast-to-noise ratio values than gated CEMRA and unenhanced 3D bSSFP (P < 0.05) and provided ninefold better fluid suppression than equilibrium phase 3D bSSFP. Aortic diameter and main pulmonary artery diameter measurements obtained with bT1RESS and first-pass gated CEMRA strongly correlated (P < 0.05).

CONCLUSIONS

We found that using bT1RESS greatly prolongs the useful duration of blood pool contrast enhancement while improving angiographic image quality compared with standard CEMRA techniques. Although further study is needed, potential advantages for vascular imaging include eliminating the current requirement for first-pass imaging along with better reliability and accuracy for a wide range of cardiovascular applications.

Invasive and Non-invasive Assessment of Non-culprit Coronary Lesions in Patients with ST-segment Elevation Myocardial Infarction

The angiographic evidence of coronary multivessel disease (MVD) increases significantly the risk of recurrent ischemic events in patients with ST-segment elevation myocardial infarction (STEMI). Recent evidence suggests that a complete revascularization strategy should be considered the standard of care in these patients and performed for significant non-culprit lesions (NCLs) after careful assessment of the individual risk-benefit ratio. However, the optimal timing and the modality for the assessment of NCLs is not fully standardized. This brief review aims to summarise the management of MVD in patients with STEMI and to provide an overview of the principal techniques used to guide revascularisation in this high-risk clinical setting.

Systematic Review of Literature Citing the ISCHEMIA Trial

PURPOSE OF REVIEW

Optimal therapy for patients with chronic coronary artery disease (CCD) has long been a topic under investigation and a subject of debate. Seeking to clarify appropriate management, the International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial compared medical management versus coronary angiography for patients with stable ischemic heart disease. Its reception in the medical community has been met with both acclaim and criticism. In light of such disparate views of this trial, a systematic review of the literature citing the ISCHEMIA trial was performed.

RECENT FINDINGS

All articles citing the ISCHEMIA trial on PubMed as of July 21, 2023, were compiled and underwent qualitative analysis. A total of 430 articles were evaluated; 109 (25.3%) did not offer substantial commentary on ISCHEMIA and cite it as background evidence for further study. Of the commentary articles, the majority (224, 52.1%) gave balanced, honest appraisals of the ISCHEMIA trial. A total of 46 (10.7%) strongly praised the trial while another 39 (9.1%) were strongly critical of the results. Almost three-quarters of the literature citing the ISCHEMIA trial was commentary in nature, with roughly equal distribution across the spectrum of praise and criticism. Despite being one of the largest studies on CCD and coronary revascularization ever conducted, the impact of ISCHEMIA on the cardiology community appears to be mixed.

Clinical implementation of a fully automated quantitative perfusion cardiovascular magnetic resonance imaging workflow with a simplified dual-bolus contrast administration scheme

This study clinically implemented a ready-to-use quantitative perfusion (QP) cardiovascular magnetic resonance (QP CMR) workflow, encompassing a simplified dual-bolus gadolinium-based contrast agent (GBCA) administration scheme and fully automated QP image post-processing. Twenty-five patients with suspected obstructive coronary artery disease (CAD) underwent both adenosine stress perfusion CMR and an invasive coronary angiography or coronary computed tomography angiography. The dual-bolus protocol consisted of a pre-bolus (0.0075 mmol/kg GBCA at 0.5 mmol/ml concentration + 20 ml saline) and a main bolus (0.075 mmol/kg GBCA at 0.5 mmol/ml concentration + 20 ml saline) at an infusion rate of 3 ml/s. The arterial input function curves showed excellent quality. Stress MBF ≤ 1.84 ml/g/min accurately detected obstructive CAD (area under the curve 0.79; 95% Confidence Interval: 0.66 to 0.89). Combined visual assessment of color pixel QP maps and conventional perfusion images yielded a diagnostic accuracy of 84%, sensitivity of 70% and specificity of 93%. The proposed easy-to-use dual-bolus QP CMR workflow provides good image quality and holds promise for high accuracy in diagnosis of obstructive CAD. Implementation of this approach has the potential to serve as an alternative to current methods thus increasing the accessibility to offer high-quality QP CMR imaging by a wide range of CMR laboratories.

Back to the basics: The need for an etiological classification of chronic heart failure

The left ventricular (LV) ejection fraction (LVEF), despite its severe limitations, has had an epicentral role in heart failure (HF) classification, management, and risk stratification for decades. The major argument favoring the LVEF based HF classification has been that it defines groups of patients in which treatment is effective. However, this reasoning has recently collapsed, since medical treatment with neurohormonal inhibitors, has proved beneficial in most HF patients regardless of the LVEF. In addition, there has been compelling evidence, that the LVEF provides poor guidance for device treatment of chronic HF (implantation of cardioverter defibrillator, cardiac resynchronization therapy) since sudden cardiac death may occur and cardiac dyssynchronization may be disastrous in all HF patients. The same holds true for LV assist device implantation, in which the LVEF has been used as a surrogate for LV size. In this review article we update the evidence questioning the use of LVEF-based HF classification and argue that guidance of chronic HF treatment should transition to more contemporary concepts. Specifically, we propose an etiologic chronic HF classification predominantly based on epidemiological data, which will be foundational for further higher resolution phenotyping in the emerging era of precision medicine.

Role of epicardial adipose tissue in diabetic cardiomyopathy through the lens of cardiovascular magnetic resonance imaging - a narrative review

Accumulating evidence suggests that ectopic/visceral adiposity may play a key role in the pathogenesis of nonischaemic cardiovascular diseases associated with type 2 diabetes. Epicardial adipose tissue (EAT) is a complex visceral fat depot, covering 80% of the cardiac surface with anatomical and functional contiguity to the myocardium and coronary arteries. EAT interacts with the biology of the underlying myocardium by secreting a wide range of adipokines. Magnetic resonance imaging (MRI) is the reference modality for structural and functional imaging of the heart. The technique is now also emerging as the reference imaging modality for EAT quantification. With this narrative review, we (a) surveyed contemporary clinical studies that utilized cardiovascular MRI to characterize EAT (studies published 2010-2023); (b) listed the clinical trials monitoring the response to treatment in EAT size as well as myocardial functional and structural parameters and (c) discussed the potential pathophysiological role of EAT in the development of diabetic cardiomyopathy. We concluded that increased EAT quantity and its inflammatory phenotype correlate with early signs of left ventricle dysfunction and may have a role in the pathogenesis of cardiac disease in diabetes with and without coronary artery disease.

Recent Advances in Cardiac Magnetic Resonance for Imaging of Acute Myocardial Infarction

Acute myocardial infarction (AMI) is one of the primary causes of death worldwide, with a high incidence and mortality rate. Assessment of the infarcted and surviving myocardium, along with microvascular obstruction, is crucial for risk stratification, treatment, and prognosis in patients with AMI. Nonionizing radiation, excellent soft tissue contrast resolution, a large field of view, and multiplane imaging make cardiac magnetic resonance (CMR) a "one-stop" method for assessing cardiac structure, function, perfusion, and metabolism. Hence, this imaging technology is considered the "gold standard" for evaluating myocardial function and viability in AMI. This review critically compares the advantages and disadvantages of CMR with other cardiac imaging technologies, and relates the imaging findings to the underlying pathophysiological processes in AMI. A more thorough understanding of CMR technology will clarify their advanced clinical diagnosis and prognostic assessment applications, and assess the future approaches and challenges of CMR in the setting of AMI.

Myocardial Blood Flow Quantified Using Stress Cardiac Magnetic Resonance After Mild COVID-19 Infection

BACKGROUND

Severe COVID-19 infection is known to alter myocardial perfusion through its effects on the endothelium and microvasculature. However, the majority of patients with COVID-19 infection experience only mild symptoms, and it is unknown if their myocardial perfusion is altered after infection.

OBJECTIVES

The authors aimed to determine if there are abnormalities in myocardial blood flow (MBF), as measured by stress cardiac magnetic resonance (CMR), in individuals after a mild COVID-19 infection.

METHODS

We conducted a prospective, comparative study of individuals who had a prior mild COVID-19 infection (n = 30) and matched controls (n = 26) using stress CMR. Stress and rest myocardial blood flow (sMBF, rMBF) were quantified using the dual sequence technique. Myocardial perfusion reserve was calculated as sMBF/rMBF. Unpaired t-tests were used to test differences between the groups.

RESULTS

The median time interval between COVID-19 infection and CMR was 5.6 (IQR: 4-8) months. No patients with the COVID-19 infection required hospitalization. Symptoms including chest pain, shortness of breath, syncope, and palpitations were more commonly present in the group with prior COVID-19 infection than in the control group (57% vs 7%, P < 0.001). No significant differences in rMBF (1.08 ± 0.27 mL/g/min vs 0.97 ± 0.29 mL/g/min, P = 0.16), sMBF (3.08 ± 0.79 mL/g/min vs 3.06 ± 0.89 mL/g/min, P = 0.91), or myocardial perfusion reserve (2.95 ± 0.90 vs 3.39 ± 1.25, P = 0.13) were observed between the groups.

CONCLUSIONS

This study suggests that there are no significant abnormalities in rest or stress myocardial perfusion, and thus microvascular function, in individuals after mild COVID-19 infection.

Seeing is believing: pathway strategies for a personalised non-invasive diagnosis of coronary artery disease

Coronary artery disease (CAD) diagnosis requires a precise assessment of patient profile and disease extension. While non-invasive imaging modalities offer an in-depth evaluation of CAD through differential approaches, this is based primarily on detecting coronary plaques or inducible myocardial ischaemia, thus each offering only a partial outlook of this condition. The improvement in appropriately identifying CAD patients at risk of developing major adverse cardiovascular events and guiding treatment outcomes will require developing a personalised diagnostic strategy for a value-based application of current technologies.

Evaluation and management of patients with coronary chronic total occlusions considered for revascularisation. A clinical consensus statement of the European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the ESC, the European Association of Cardiovascular Imaging (EACVI) of the ESC, and the ESC Working Group on Cardiovascular Surgery

Chronic total occlusions (CTOs) of coronary arteries can be found in the context of chronic or acute coronary syndromes; sometimes they are an incidental finding in those apparently healthy individuals undergoing imaging for preoperative risk assessment. Recently, the invasive management of CTOs has made impressive progress due to sophisticated preinterventional assessment, including advanced non-invasive imaging, the availability of novel and dedicated tools for CTO percutaneous coronary intervention (PCI), and experienced interventionalists working in specialised centres. Thus, it is crucial that referring physicians who see patients with CTO be aware of recent developments and of the initial evaluation requirements for such patients. Besides a careful history and clinical examination, electrocardiograms, exercise tests, and non-invasive imaging modalities are important for selecting the patients most suitable for CTO PCI, while others may be referred to coronary artery bypass graft or optimal medical therapy only. While CTO PCI improves angina and reduces the use of antianginal drugs in patients with symptoms and proven ischaemia, hibernation and/or wall motion abnormalities at baseline or during stress, the effect of CTO PCI on major cardiovascular events is still controversial. This clinical consensus statement specifically focuses on referring physicians, providing a comprehensive algorithm for the preinterventional evaluation of patients with CTO and the current evidence for the clinical effectiveness of the procedure. The proposed care track has been developed by members and with the support of the European Association of Percutaneous Cardiovascular Interventions (EAPCI), the European Association of Cardiovascular Imaging (EACVI), and the European Society of Cardiology (ESC) Working Group on Cardiovascular Surgery.

Perfusion Imaging for the Heart

The use of myocardial perfusion imaging during a stress cardiac magnetic resonance (CMR) examination for the evaluation of coronary artery disease is now recommended by both US and European guidelines. Several studies have demonstrated high diagnostic accuracy for the detection of hemodynamically significant coronary artery disease. Stress perfusion CMR has been shown to be a noninvasive and cost-effective alternative to guide coronary revascularization.

Review and critical appraisal of the indications for cardiac magnetic resonance imaging in the ESC guidelines

Cardiac MRI has made significant advances in the past decade, becoming an important technique for the evaluation of various cardiac pathologies. The aim of this document is to review the current indications for performing cardiac MRI based on the current ESC guidelines for STEMI, NSTEMI, chronic coronary artery disease, heart failure, arrhythmias, sudden cardiac death, valvular heart disease, pericardial disease and congenital heart disease. The review discusses the diagnostic and prognostic value of cMR for numerous cardiac diseases, and its important value in assessing structural heart disease and predicting arrhythmia risk. Additionally, it reflects upon the appropriateness of the guidelines and points out areas where the indications should be revised in future editions, based on the author's personal opinion. It is suggested that guideline criteria for the use of cMR should be more explicit to promote its use and lead to more specific reimbursements. However, further studies are needed to even better document the value of cMR in the future.

Multivessel Coronary Artery Disease Presenting as a False-Negative Nuclear Stress Test: A Case of Balanced Ischemia

Myocardial perfusion imaging (MPI) is fundamental to comparing coronary vessel perfusion levels and guides in identifying ischemic areas. However, false negatives, such as balanced ischemia, are important considerations in interpreting these results. In this case report, we describe a 77-year-old female who presented with cardiac chest pain with normal laboratory results, electrocardiogram, and imaging. However, given her history and risk factors, left heart catheterization was performed, which showed triple vessel coronary artery disease.

Myocardial Late Gadolinium Enhancement (LGE) in Cardiac Magnetic Resonance Imaging (CMR)-An Important Risk Marker for Cardiac Disease

Cardiovascular magnetic resonance (CMR) has significantly revolutionized the comprehension and diagnosis of cardiac diseases, particularly through the utilization of late gadolinium enhancement (LGE) imaging for tissue characterization. LGE enables the visualization of expanded extracellular spaces in conditions such as fibrosis, fibrofatty tissue, or edema. The growing recognition of LGE's prognostic capacity underscores its importance, evident in the increasing explicit recommendations within guidelines. Notably, the contemporary characterization of cardiomyopathies relies on LGE-based scar assessment by CMR to a large extent. This review describes the pattern and prognostic value of LGE in detail for various cardiac diseases. Despite its merits, establishing LGE as a reliable risk marker encounters challenges. Limitations arise from the fact that not all diseases show LGE, and it should always be analyzed in the context of all CMR sequences and the patient's medical history. In summary, LGE stands as a robust indicator of adverse outcomes in diverse cardiovascular diseases. Its further integration into routine practice is desirable, necessitating widespread availability and application to accumulate both individual and scientific experience.