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Coronary microvascular dysfunction (MVD) is diagnosed when there is impaired coronary flow reserve (CFR) in the context of unobstructed arteries, but the optimum diagnostic threshold remains unclear. Patients with angina and unobstructed coronary arteries were enrolled. Average peak flow velocity (

Cardiovascular Division, Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation Centre of Excellence, National Institute of Health ResearchBiomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, United Kingdom

Kawasaki disease (KD) is a generalized systemic vasculitis, although the coronary artery system is typically involved. Coronary artery lesions (CAL) develop in 25% of children during the acute stage of KD and may lead to infarction, sudden death, or chronic coronary artery insufficiency [(1)][1]. In

Objectives This study sought to compare computed tomography delayed enhancement (CTDE) against cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) for detection of ischemic scar and to test the additive value of CTDE as part of a comprehensive multidetector computed tomography (MDCT) stress–rest protocol including computed tomography perfusion (CTP) and computed tomography angiography (CTA) for the diagnosis of significant coronary artery disease (CAD). Background CTDE has been recently described as a promising tool for noninvasive detection of myocardial scar, similarly to CMR-LGE techniques. Despite its theoretical potential as an adjunctive tool to improve MDCT accuracy for detection of CAD, its clinical performance has not been validated. Methods One hundred five symptomatic patients with suspected CAD (age 62.0 ± 8.0 years, 67% men) underwent MDCT, CMR, and x-ray invasive coronary angiography. The MDCT protocol consisted of calcium scoring, stress CTP under adenosine 140 μg/kg/min, rest CTP + CTA, and a low-dose radiation prospective scan for detection of CTDE. CMR-LGE was used as the reference standard for assessment of scar. Functionally significant CAD was defined as the presence of ≥90% stenosis/occlusion or fractional flow reserve measurements ≤0.80 in vessels >2 mm. Results CTDE had good accuracy (90%) for ischemic scar detection with low sensitivity (53%) but excellent specificity (98%). Positive and negative predictive values were 82% and 91%, respectively. On a patient-based model, MDCT protocol without integration of CTDE results had a sensitivity, specificity, and positive and negative predictive values of 90%, 81%, 80%, and 90%, respectively, for the detection of functionally significant CAD. Addition of CTDE results did not improve MDCT performance (90%, 77%, 77%, and 90%, respectively). Conclusions CTDE has moderate accuracy for detection of ischemic scar in patients with suspected CAD. Integration of CTDE into a comprehensive MDCT protocol including stress–rest CTP and CTA does not improve MDCT accuracy for detection of significant CAD in intermediate-to-high pre-test probability populations.

Kawasaki disease (KD) is a vasculitis affecting the coronary and systemic arteries. Myocardial inflammation is also a common finding in KD post-mortem evaluation during the acute phase of the disease. Coronary artery aneurysms (CAAs) develop in 15–25 % of untreated children. Although 50–70 % of CAAs resolve spontaneously 1–2 years after the onset of KD, the remaining unresolved CAAs can develop stenotic lesions at either their proximal or distal end and can develop thrombus formation leading to ischemia and/or infarction. Cardiovascular magnetic resonance (CMR) has the ability to perform non-invasive and radiation-free evaluation of the coronary artery lumen. Recently tissue characterization of the coronary vessel wall was provided by CMR. It can also image myocardial inflammation, ischemia and fibrosis. Therefore CMR offers important clinical information during the acute and chronic phase of KD. In the acute phase, it can identify myocardial inflammation, microvascular disease, myocardial infarction, deterioration of left ventricular function, changes of the coronary artery lumen and changes of the coronary artery vessel wall. During the chronic phase, CMR imaging might be of value for risk stratification and to guide treatment.

Recent studies have demonstrated that a detailed knowledge of the extent of angiographic coronary artery disease (CAD) is not a prerequisite for clinical decision making, and the clinical management of patients with CAD is more and more focused towards the identification of myocardial ischemia and the quantification of ischemic burden. In this view, non-invasive assessment of ischemia and in particular stress imaging techniques are emerging as preferred and non-invasive options. A quantitative assessment of regional myocardial perfusion can provide an objective estimate of the severity of myocardial injury and may help clinicians to discriminate regions of the heart that are at increased risk for myocardial infarction. Positron emission tomography (PET) has established itself as the reference standard for myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) quantification. Cardiac magnetic resonance (CMR) is increasingly used to measure MBF and MPR by means of first-pass signals, with a well-defined diagnostic performance and prognostic value. The aim of this article is to review the currently available evidence on the use of both PET and CMR for quantification of MPR, with particular attention to the studies that directly compared these two diagnostic methods.

Objectives This study sought to test the hypothesis that transmural perfusion gradients (TPG) on adenosine stress myocardial perfusion cardiac magnetic resonance (CMR) predict hemodynamically significant coronary artery disease (CAD) as defined by fractional flow reserve (FFR). Background Myocardial ischemia affects the subendocardial layers of the left ventricular myocardium earlier and more severely than the outer layers, and the identification of TPG should be sensitive and specific for the diagnosis of CAD. Previous studies have shown that high spatial resolution myocardial perfusion CMR allows quantitation of TPG between the subendocardium and the subepicardium. Methods Sixty-seven patients (53 men, age 61 ± 9 years) underwent coronary angiography and high-resolution (1.2 × 1.2-mm in-plane) adenosine stress perfusion CMR at 3.0-T. TPG was calculated for 3 coronary territories. Visual analysis was performed to identify myocardial ischemia. FFR was measured in all vessels with ≥50% severity stenosis. FFR Results In Group 1, a 20% TPG provided the best diagnostic threshold on both per-segment and per-patient analysis. Applied to Group 2, this threshold yielded a sensitivity of 0.78, specificity of 0.94, and area under the curve of 0.86 for the detection of CAD in a per-segment analysis and of 0.89, 0.83, and 0.86 in a per-patient analysis, respectively. TPG had a similar diagnostic accuracy to visual assessment. Linear regression analysis showed a relationship between TPG and FFR values, with r = 0.63 (p Conclusions The quantitative analysis of transmural perfusion gradients on high-resolution myocardial perfusion CMR accurately predicts hemodynamically significant CAD as defined by FFR. A TPG diagnostic threshold of 20% is as accurate as visual assessment.

Purpose: Robust motion correction is necessary to minimize respiratory motion artefacts in coronary MR angiography (CMRA). The state-of-the-art method uses a 1D feet-head translational motion correction approach, and data acquisition is limited to a small window in the respiratory cycle, which prolongs the scan by a factor of 2–3. The purpose of this work was to implement 3D affine motion correction for Cartesian whole-heart CMRA using a 3D navigator (3D-NAV) to allow for data acquisition throughout the whole respiratory cycle. Methods: 3D affine transformations for different respiratory states (bins) were estimated by using 3D-NAV image acquisitions which were acquired during the startup profiles of a steady-state free precession sequence. The calculated 3D affine transformations were applied to the corresponding high-resolution Cartesian image acquisition which had been similarly binned, to correct for respiratory motion between bins. Results: Quantitative and qualitative comparisons showed no statistical difference between images acquired with the proposed method and the reference method using a diaphragmatic navigator with a narrow gating window. Conclusion: We demonstrate that 3D-NAV and 3D affine correction can be used to acquire Cartesian whole-heart 3D coronary artery images with 100% scan efficiency with similar image quality as with the state-of-the-art gated and corrected method with approximately 50% scan efficiency. Magn Reson Med 71:173–181, 2014. V C 2013 Wiley Periodicals

Purpose An isolated perfused pig heart model has recently been proposed for the development of novel methods in standard clinical magnetic resonance (MR) scanners. The original set-up required the electrical system to be within the safe part of the MR-room, which introduced significant background noise. The purpose of the current work was to refine the system to overcome this limitation so that all electrical parts are completely outside the scanner room. Methods Four pig hearts were explanted under terminal anaesthesia from large white cross landrace pigs. All hearts underwent cardiovascular magnetic resonance (CMR) scanning in the MR part of a novel combined 3T MR and x-ray fluoroscopy (XMR) suite. CMR scanning included real-time k-t SENSE functional imaging, k-t SENSE accelerated perfusion imaging and late gadolinium enhancement imaging. Interference with image quality was assessed by spurious echo imaging and compared to noise levels acquired while operating the electrical parts within the scanner room. Results Imaging was performed successfully in all hearts. The system proved suitable for isolated heart perfusion in a novel 3T XMR suite. No significant additional noise was introduced into the scanner room by our set-up. Conclusions We have substantially improved a previous version of an isolated perfused pig heart model and made it applicable for MR imaging in a state of the art clinical 3T XMR imaging suite. The use of this system should aid novel CMR sequence development and translation into clinical practice.

Introduction The role of implantable cardioverter defibrillators in non-ischemic cardiomyopathy is unclear and better risk-stratification is required. We sought to determine if T1 mapping predicts appropriate defibrillator therapy in patients with non-ischemic cardiomyopathy. We studied a mixed cohort of ischemic and non-ischemic patients to determine whether different CMR applications (T1 mapping, late gadolinium enhancement and Grayzone) were selectively predictive of therapies for the different arrhythmic substrates. Methods and Results We undertook a prospective longitudinal study of consecutive patients receiving defibrillators in a tertiary cardiac center. Participants underwent CMR myocardial tissue-characterization using T1 mapping and conventional CMR scar assessment before device implantation. QRS duration and fragmentation on the surface electrocardiogram were also assessed. The primary endpoint was appropriate defibrillator therapy. One hundred thirty patients were followed up for a median of 31 months (IQR (+/-9 months). In non-ischemic patients T1_native was the sole predictor of the primary endpoint (HR 1.12 per 10ms increment in value (95% C.I 1.04-1.21; p≤0.01). In ischemic patients, Grayzone_2SD-3SD was the strongest predictor of appropriate therapy (HR 1.34 per 1% left ventricular increment in value (95% C.I 1.03-1.76;p = 0.03). QRS fragmentation correlated well with myocardial scar core (ROC AUC 0.64; p = 0.02) but poorly with T1_native (ROC AUC 0.4) and did not predict appropriate therapy. Conclusions In the medium-long term, T1_native mapping was the only independent predictor of therapy in non-ischemic patients whereas Grayzone was a better predictor in ischemic patients. These findings suggest a potential role for T1_native mapping in the selection of patients for ICDs in a non-ischemic population. This article is protected by copyright. All rights reserved

The coronary arterial system consists of large epicardial coronary arteries, pre-arterioles, and arterioles, which together closely regulate CBF. Structural, functional, and extravascular abnormalities of the microcirculation lead to CMD. CMD can present with symptoms suggestive of CAD, often in the absence of significant obstructive epicardial CAD. Conventional invasive angiography does not allow direct visualization of the microcirculation. Invasive indices, such as CBF and CFR, and non-invasive imaging modalities, such as CMR and PET, can be used to quantify absolute MBF and enable a direct and accurate assessment of coronary microvascular function. CMD appears to be more prevalent in women, typically presenting with symptoms of ischemia with unobstructed coronary arteries, and has a relatively unfavorable prognosis. CMD is classified clinically depending on the presence or absence of epicardial CAD, myocardial disease, or iatrogenic causes. Although invasive intracoronary techniques can be used to detect CMD, these cannot provide insight into the mechanisms involved in its pathogenesis. Imaging modalities such as CMR and cardiac PET are becoming indispensable tools in the evaluation of suspected CMD.

Purpose To propose a 3D quantitative high‐resolution T 1 mapping technique, called 3D SASHA (saturation‐recovery single‐shot acquisition), which combines a saturation recovery pulse with 1D‐navigator‐based‐respiratory motion compensation to acquire the whole volume of the heart in free breathing. The sequence was tested and validated both in a T 1 phantom and in healthy subjects. Materials and Methods The 3D SASHA method was implemented on a 1.5T scanner. A diaphragmatic navigator was used to allow free‐breathing acquisition and the images were acquired with a resolution of 1.4 × 1.4 × 8 mm3. For assessment of accuracy and precision the sequence was compared with the reference gold‐standard inversion‐recovery spin echo (IRSE) pulse sequence in a T 1 phantom, while for the in vivo studies (10 healthy volunteers) 3D SASHA was compared with the clinically used 2D MOLLI (3‐3‐5) and 2D SASHA protocols. Results There was good agreement between the T 1 values measured in a T 1 phantom with 3D SASHA and the reference IRSE pulse sequences (1111.6 ± 31 msec vs. 1123.6 ± 8 msec, P = 0.9947). Mean and standard deviation of the myocardial T 1 values in healthy subjects measured with 2D MOLLI, 2D SASHA, and 3D SASHA sequences were 881 ± 40 msec, 1181.3 ± 32 msec, and 1153.6 ± 28 msec respectively. Conclusion The proposed 3D SASHA sequence allows for high‐resolution free‐breathing whole‐heart T 1‐mapping with T 1 values in good agreement with the 2D SASHA and improved precision. Level of Evidence: 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:218–227

The aim of this review is to give a comprehensive and concise overview of coronary embryology and normal coronary anatomy, describe common variants of normal and summarize typical patterns of anomalous coronary artery anatomy. Extensive iconography supports the text, with particular attention to images obtained in vivo using non-invasive imaging. We have divided this article into three groups, according to their frequency in the general population: Normal, normal variant and anomaly. Although congenital coronary artery anomalies are relatively uncommon, they are the second most common cause of sudden cardiac death among young athletes and therefore warrant detailed review. Based on the functional relevance of each abnormality, coronary artery anomalies can be classified as anomalies with obligatory ischemia, without ischemia or with exceptional ischemia. The clinical symptoms may include chest pain, dyspnea, palpitations, syncope, cardiomyopathy, arrhythmia, myocardial infarction and sudden cardiac death. Moreover, it is important to also identify variants and anomalies without clinical relevance in their own right as complications during surgery or angioplasty can occur.

Moreover, the same MRA techniques allow the visualization of the coronary veins anatomy, which is of interest for the optimal placement of pacemaker leads in cardiac resynchronization therapy.7,8Amedeo Chiribiri, Markus Henningsson, Claudia Prieto, Michael Jerosch-Herold, and Rene M. BotnarCONTENTS1.1 Introduction 1 1.2 Technical Challenges and General Imaging Strategies for Coronary CMR 21.2.1 Compensation of Cardiac Motion: ECG Triggering 2 1.2.2 Compensation of Respiratory Motion: Navigator 2 1.2.3 Coronary Artery Imaging 31.2.3.1 Sequences 3 1.2.3.2 Contrast-Enhancing Spin Preparations 4 1.2.3.3 Contrast Agents 4 1.2.3.4 Recent Improvements in Acquisition Speed and Resolution 51.2.4 Coronary Vein Imaging 5 1.2.5 Coronary Vessel Wall Imaging 5 1.2.6 Special Considerations: Intracoronary Stents 71.3 Clinical Applications 7 1.3.1 Coronary Artery Angiography for the Detection of CAD 7 1.3.2 Coronary Anomalies and Aneurysms 8 1.3.3 Coronary Bypass Grafts 8 1.3.4 Coronary Vessel Wall Imaging 8 1.3.5 Coronary Vein Imaging 81.4 Myocardial Perfusion Imaging 8 1.4.1 Techniques for Magnetic Resonance Myocardial Perfusion Imaging 9 1.4.2 Clinical Applications 121.5 Conclusions-Future Perspective 12 References 13This chapter provides an update on current improvements in coronary MRA as well as an overview on its current clinical usage.

Validation of the proposed theory in multiple species reveals the equivalence between scaling laws and well-matchedness in the vasculature. Moreover, it captures the role of pulsatility in optimal vascular designs. This demonstrates the forward well-matchedness of coronary bifurcations, whereas backward waves are damped asymmetrically at junctions., The branching pattern of the coronary vasculature is a key determinant of its function and plays a crucial role in shaping the pressure and velocity wave forms measured for clinical diagnosis. However, although multiple scaling laws have been proposed to characterize the branching pattern, the implications they have on wave propagation remain unassessed to date. To bridge this gap, we have developed a new theoretical framework by combining the mathematical formulation of scaling laws with the wave propagation theory in the pulsatile flow regime. This framework was then validated in multiple species using high-resolution cryomicrotome images of porcine, canine, and human coronary networks. Results demonstrate that the forward well-matchedness (no reflection for pressure/flow waves traveling from the coronary stem toward the microcirculation) is a salient feature in the coronary vasculature, and this result remains robust under many scenarios of the underlying pulse wave speed distribution assumed in the network. This result also implies a significant damping of the backward traveling waves, especially for smaller vessels (radius

BACKGROUND: Microvascular ischemia is one of the hallmarks of hypertrophic cardiomyopathy (HCM) and has been associated with poor outcome. However, myocardial fibrosis, seen on cardiovascular magnetic resonance (CMR) as late gadolinium enhancement (LGE), can be responsible for rest perfusion defects in up to 30% of patients with HCM, potentially leading to an overestimation of the ischemic burden. We investigated the effect of left ventricle (LV) scar on the total LV ischemic burden using novel high-resolution perfusion analysis techniques in conjunction with LGE quantification.METHODS: 30 patients with HCM and unobstructed epicardial coronary arteries underwent CMR with Fermi constrained quantitative perfusion analysis on segmental and high-resolution data. The latter were corrected for the presence of fibrosis on a pixel-by-pixel basis.RESULTS: High-resolution quantification proved more sensitive for the detection of microvascular ischemia in comparison to segmental analysis. Areas of LGE were associated with significant reduction of myocardial perfusion reserve (MPR) leading to an overestimation of the total ischemic burden on non-corrected perfusion maps. Using a threshold MPR of 1.5, the presence of LGE caused an overestimation of the ischemic burden of 28%. The ischemic burden was more severe in patients with fibrosis, also after correction of the perfusion maps, in keeping with more severe disease in this subgroup.CONCLUSIONS: LGE is an important confounder in the assessment of the ischemic burden in patients with HCM. High-resolution quantitative analysis with LGE correction enables the independent evaluation of microvascular ischemia and fibrosis and should be used when evaluating patients with HCM.

ObjectivesTo determine the inter-study reproducibility of left ventricular (LV) mechanical dyssynchrony measures based on standard cardiovascular magnetic resonance (CMR) cine images.DesignSteady-state free precession (SSFP) LV short-axis stacks and three long-axes were acquired on the same day at three time points. Circumferential strain systolic dyssynchrony indexes (SDI), area-SDI as well as circumferential and radial uniformity ratio estimates (CURE and RURE, respectively) were derived from CMR myocardial feature-tracking (CMR-FT) based on the tracking of three SSFP short-axis planes. Furthermore, 4D-LV-analysis based on SSFP short-axis stacks and longitudinal planes was performed to quantify 4D-volume-SDI.SettingA single-centre London teaching hospital.Participants16 healthy volunteers.Main outcome measuresInter-study reproducibility between the repeated exams.ResultsCURE and RURE as well as 4D-volume-SDI showed good inter-study reproducibility (coefficient of variation [CoV] 6.4%–12.9%). Circumferential strain and area-SDI showed higher variability between the repeated measurements (CoV 24.9%–37.5%). Uniformity ratio estimates showed the lowest inter-study variability (CoV 6.4%–8.5%).ConclusionsDerivation of LV mechanical dyssynchrony measures from standard cine images is feasible using CMR-FT and 4D-LV-analysis tools. Uniformity ratio estimates and 4D-volume-SDI showed good inter-study reproducibility. Their clinical value should next be explored in patients who potentially benefit from cardiac resynchronization therapy.

Background Perfusion cardiovascular magnetic resonance (CMR) and fractional flow reserve (FFR) are emerging as the most accurate tools for the assessment of myocardial ischemia noninvasively or in the catheter laboratory. However, there is limited data comparing CMR and FFR in patients with multi-vessel disease. This study aims to evaluate the correlation between myocardial ischemia detected by CMR with FFR in patients with multivessel coronary disease at angiography. Methods and results Forty-one patients (123 vascular territories) with angiographic 2- or 3-vessel coronary artery disease (visual stenosis >50 %) underwent high-resolution adenosine stress perfusion CMR at 1.5 T and FFR measurement. An FFR value of On a per patient basis, CMR and FFR detected identical ischemic territories in 19 patients (46 %) (mean number of territories 0.7+/−0.7 in both (p = 1.0)). On a per vessel basis, 89 out of 123 territories demonstrated concordance between the CMR and FFR results (72 %). In 34 % of the study population, CMR resulted in fewer ischemic territories than FFR; in 12 % CMR resulted in more ischemic territories than FFR. There was good concordance between the two methods to detect myocardial ischemia on a per-patient (k =0.658 95 % CI 0.383-0.933) level and moderate concordance on a per-vessel (k = 0.453 95 % CI 0.294–0.612) basis. Conclusions There is good concordance between perfusion CMR and FFR for the identification of myocardial ischemia in patients with multi-vessel disease. However, some discrepancy remains and at this stage it is unclear whether CMR underestimates or FFR overestimates the number of ischemic segments in multi-vessel disease.

OBJECTIVES: The aim of this study was to compare fully quantitative cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) myocardial perfusion and myocardial perfusion reserve (MPR) measurements in patients with coronary artery disease (CAD).BACKGROUND: Absolute quantification of myocardial perfusion and MPR with PET have proven diagnostic and prognostic roles in patients with CAD. Quantitative CMR perfusion imaging has been established more recently and has been validated against PET in normal hearts. However, there are no studies comparing fully quantitative CMR against PET perfusion imaging in patients with CAD.METHODS: Forty-one patients with known or suspected CAD prospectively underwent quantitative (13)N-ammonia PET and CMR perfusion imaging before coronary angiography.RESULTS: The CMR-derived MPR (MPR(CMR)) correlated well with PET-derived measurements (MPR(PET)) (r = 0.75, p < 0.0001). MPR(CMR) and MPR(PET) for the 2 lowest scoring segments in each coronary territory also correlated strongly (r = 0.79, p < 0.0001). Absolute CMR perfusion values correlated significantly, but weakly, with PET values both at rest (r = 0.32; p = 0.002) and during stress (r = 0.37; p < 0.0001). Area under the receiver-operating characteristic curve for MPR(PET) to detect significant CAD was 0.83 (95% confidence interval: 0.73 to 0.94) and for MPR(CMR) was 0.83 (95% confidence interval: 0.74 to 0.92). An MPR(PET) ≤1.44 predicted significant CAD with 82% sensitivity and 87% specificity, and MPR(CMR) ≤1.45 predicted significant CAD with 82% sensitivity and 81% specificity.CONCLUSIONS: There is good correlation between MPR(CMR) and MPR(PET.) For the detection of significant CAD, MPR(PET) and MPR(CMR) seem comparable and very accurate. However, absolute perfusion values from PET and CMR are only weakly correlated; therefore, although quantitative CMR is clinically useful, further refinements are still required. (Less)

Purpose Platelet-derived stromal-cell-derived factor-1 (SDF-1) plays an important role in trafficking hematopoetic progenitor cells for tissue regeneration and neovascularisation. The aim was to evaluate platelet-SDF-1 and CD34 + progenitor cells in patients with acute myocardial infarction (AMI) compared with hemodynamic function and infarct size using late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging. Materials and methods We consecutively evaluated 40 patients with AMI, who received coronary angiography for primary coronary intervention. Blood was sampled for flow cytometry to determine mean fluorescence intensity (MFI) of platelet-SDF-1 and for isolation of CD34 + progenitor cells. 48 h and three months after coronary stenting, all patients underwent 1.5 T CMR for volumetric assessment and LGE. Results Patients with enhanced platelet-SDF-1 expression (median ≥ 68.5 MFI) showed a significant amelioration of left ventricular ejection fraction (LVEF) (baseline vs. follow-up mean ± SD: 45 ± 6% vs. 56 ± 6%; P = 0.018) and of stroke volume (73.1 ± 19.1 mL vs. 89.9 ± 21.3 mL; P = 0.032) at three-month follow-up in contrast to patients with a decreased platelet-SDF-1 expression level (LVEF: 53 ± 8% vs. 56 ± 10%; P = 0.267; stroke volume: 85.6 ± 23.1 mL vs. 87.4 ± 23.2 mL; P = 0.803). Inversely, LGE infarct size showed significantly reduced in patients with enhanced platelet-SDF-1 expression at three months (18.9 ± 12 mL vs. 6.3 ± 5.1 mL; P = 0.002) compared to patients with decreased platelet-SDF-1 (12.7 ± 12.7 mL vs. 7.6 ± 8.4 mL; P = 0.156). Time-dependent autocorrelation coefficients shifted for both SV (lag 1: r = −0.368; P = 0.001) and the number of CD34 + cells (lag 1: r = 0.633; P = 0.001) to a positive autocorrelation (SV; lag 2: r = 0.295; P = 0.001; CD34 + cells; lag 2: r = 0.287; P = 0.001). Patients with increased number of CD34 + cells (median ≥ 420 cells/hpf) showed a significant amelioration of stroke volume in three-month follow-up (83.9 ± 5.3 mL vs. 99.4 ± 4.1 mL; P = 0.020) compared with patients with decreased number of CD34 + cells (69.3 ± 4.1 mL vs. 76.1 ± 3.2 mL; P = 0.282). Conclusions Platelet-SDF-1 and number of CD34 + progenitor cells are associated with CMR hemodynamic function in patients with AMI.

We have evaluated the use of deconvolution using an exponential approximation basis for the quantification of myocardial blood flow from perfusion cardiovascular magnetic resonance. Our experiments, based on simulated signal intensity curves, phantom acquisitions, and clinical image data, indicate that exponential deconvolution allows for accurate quantification of myocardial blood flow. Together with automated respiratory motion correction myocardial contour delineation, the exponential deconvolution enables efficient and reproducible quantification of myocardial blood flow in clinical routine.

Heart failure of ischemic origin has become increasingly common over the last decade because of the improved survival of patients with acute myocardial infarction. Revascularization with coronary bypass grafting or percutaneous coronary intervention plays a pivotal role in patients with ischemic cardiomyopathy, although these interventions are often associated with relatively high peri-procedural risk. The pathophysiological substrate of ischemic cardiomyopathy is heterogeneous, varying from predominantly hibernating myocardium to irreversible scarring. There is evidence to suggest that patients with hibernating myocardium benefit most from revascularization, whereas medical therapy is associated with an adverse prognosis. Therefore, noninvasive testing is recommended by relevant guidelines to guide optimal management in these patients. However, the role of noninvasive testing has recently been challenged. There are various imaging modalities available that provide information on different aspects of the disease, and therefore, they differ significantly in sensitivity and specificity. In clinical practice, choosing among the different imaging modalities can be difficult. Cardiac magnetic resonance has evolved into a comprehensive modality that can accurately determine the amount of hibernating myocardium as well as the presence and degree of myocardial ischemia and the extent of the scar. This paper reviews the indications, accuracy, and clinical utility of the available imaging techniques, with a special focus on cardiac magnetic resonance in ischemic cardiomyopathy, and provides an outlook on how this field might evolve in the future.

Vascular lesion formation and collagen presentation are key events leading to the development of vulnerable plaques. Glycoprotein VI (GPVI) significantly contributes to plaque-associated collagen binding and thrombus formation. The aim of this study was to image endothelial injury using fluorescence-labelled GPVI-Fc (Fc, fragment crystallized), a soluble form of GPVI that was generated by cloning and fusing GPVI to an Fc-domain, in an ex-vivo rabbit model. This study serves as a proof-of-principle study to demonstrate that GPVI-Fc is a useful tool for detecting endothelial damage. The carotid and femoral arteries and the aorta abdominalis were isolated from rabbits and perfused with phosphate buffered saline (PBS) to remove all blood, and a catheter was placed into the vessels in situ. Endothelial damage was achieved by pulling an inflated balloon approximately 1 inch through the vessels, while control vessels were not balloon-treated. After balloon deflation, the catheter was removed. Fluorescence-labelled GPVI-Fc (50 µg/mL) was injected into the injured and control intact vessels, and the opened vessels were sealed by clamps. After incubation, the vessels were rinsed with PBS, and optical imaging was performed to measure GPVI-Fc binding to injured endothelium. The optical data corresponding to the mean detected optical signal of the regions of interest were corrected by subtracting the mean data of the background fluorescence (arbitrary units). After denudation, fluorescence was enhanced in injured femoral and carotid arteries when compared to intact femoral (41.1 ± 17.5 vs. 14.6 ± 6.5; P = 0.021) and carotid (30.2 ± 7.6 vs. 7.9 ± 3.9; P = 0.005) arteries. This preclinical GPVI-Fc-based vascular lesion imaging approach may be the first step towards a method that allows identification of vascular lesions in vivo.

BACKGROUND Platelet glycoprotein VI (pGPVI) expression is increased in acute coronary syndrome (ACS), reflecting platelet activation. There is no reliable method available to measure pGPVI. Our aim was to develop a bead-based sandwich immunoassay to measure soluble GPVI (sGPVI). METHODS Based on antibodies for sGPVI developed earlier, we established and validated a bead-based sandwich immunoassay in 2438 consecutive patients with stable angina pectoris (SAP; n = 1371), non–ST-elevation myocardial infarction (NSTEMI; n = 724), and ST-elevation MI (STEMI; n = 343). In a subgroup (n = 1011), we measured surface expression of pGPVI using flow cytometry. RESULTS The assay revealed a working range of 8–500 ng/L. Intra- and interassay imprecision was CONCLUSIONS This sandwich immunoassay reliably measures sGPVI and may help to identify patients with ACS earlier than other laboratory markers.

Background Cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) can identify areas of myocardial fibrosis in vivo in patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to examine the association between clinical-morphological variables, risk factor for sudden death, and LGE findings in a consecutive, unselected population of HCM patients. Methods From January 2005 to August 2009, 124 HCM patients (53 ± 17 years, 86 men) were prospectively evaluated with CMR examination, assessing left ventricular (LV) hypertrophy, function, and LGE. Results In univariate analysis, patients were divided into tertiles according to the number of segments positive for LGE (first tertile, 0.3 ± 0.4; second tertile, 2.2 ± 0.4; third tertile, 5.2 ± 1.9 segments). Male gender ( P = .05), maximum LV wall thickness ( P = .002), nonsustained ventricular tachycardia ( P = .001), ejection fraction P = .02), LV mass ( P = .02), left atrium dilation ( P = .04), perfusion defects ( P ≤ .001), and telesystolic volume ( P = .04) were all positively related with the number of segments of LGE. In multivariable analysis, male gender ( P = .007), maximum LV wall thickness ( P = .006), LV mass ( P = .031), and perfusion alterations ( P = .017) were independent predictors of LGE extent. Conclusions Our study shows an independent association, even at multivariate analysis, between the entity of LGE and maximum LV wall thickness, mass, and perfusion defects in patients with HCM. Whether the presence and the extent of LGE translates into clinical events later on awaits further long-term follow-up studies.

Conventional quantitative assessments of myocardial perfusion analyze the temporal relation between the arterial input function and the myocardial signal intensity curves, thereby neglecting the important spatial relation between the myocardial signal intensity curves. The new method presented in this article enables characterization of sub-endocardial to sub-epicardial gradients in myocardial perfusion based on a two dimensional, "gradientogram" representation, which displays the evolution of the transmural gradient in myocardial contrast uptake over time in all circumferential positions of the acquired images. Moreover, based on segmentation in these gradientograms, several new measurements that characterize transmural myocardial perfusion distribution over time are defined. In application to clinical image data, the new two-dimensional representations, as well as the newly defined measurements revealed a clear distinction between normal perfusion and inducible ischaemia. Thus, the new measurements may serve as diagnostic markers for the detection and characterization of epicardial coronary and microvascular disease.

ObjectivesThe aim of this study was to assess the long-term value of high-dose dobutamine cardiac magnetic resonance (DCMR) for the prediction of cardiac events in a large cohort of patients with known or suspected coronary artery disease.BackgroundHigh-dose DCMR has been shown to be a useful technique for diagnosis and intermediate-term prognostic stratification.MethodsClinical data and DCMR results were analyzed in 1,463 consecutive patients undergoing DCMR between 2000 and 2004. Ninety-four patients were lost to follow-up. The remaining 1,369 patients were followed up for a mean of 44 ± 24 months. Cardiac events, defined as cardiac death and nonfatal myocardial infarction, were related to clinical and DCMR results.ResultsThree-hundred fifty-two patients underwent early revascularization (≤3 months of DCMR) and were excluded from analysis. Of the remaining 1,017 patients, 301 patients (29.6%) experienced inducible wall motion abnormalities (WMA). Forty-six cardiac events were reported. In those with and without inducible WMA, the proportion of patients with cardiac events was 8.0% versus 3.1%, respectively, p = 0.001 (hazard ratio: 3.3; 95% confidence interval: 1.8 to 5.9 for the presence of inducible WMA; p < 0.001). A DCMR without inducible WMA carried an excellent prognosis, with a 6-year cardiac event-free survival of 96.8%. In all 1,369 patients in the patient group with stress-inducible WMA, those patients with medical therapy demonstrated a trend to a higher cardiac event rate (8.0%) than those with early revascularization (5.4%) (p = 0.234). Patients with normal DCMR and medical therapy or early revascularization demonstrated similar cumulative cardiac event rates (3.1% vs. 3.2%, p = 0.964).ConclusionsIn a large cohort of patients, DCMR has an added value for predicting cardiac events during long-term follow-up, improving the differentiation between high-risk and low-risk patients. Patients with inducible WMA and following early revascularization, demonstrate lower cardiac event rates than patients with medical therapy alone.

Purpose To evaluate a cardiac MR (CMR) examination with slow infusion of a high-relaxivity contrast agent to visualize coronary venous anatomy (CVA) and myocardial scar in heart failure patients awaiting cardiac resynchronization therapy (CRT). Materials and Methods Fourteen patients awaiting CRT (seven ischemic cardiomyopathy (ICM) and seven non-ICM) and two with normal LV function underwent CMR on a 1.5 Tesla (T) MR scanner. Dimeglumine-gadobenate was slowly infused. Bolus arrival in the LV was measured by a dynamic electrocardiogram (ECG) -triggered inversion recovery (IR) scan subsequent to starting an ECG-triggered respiratory-navigated three-dimensional (3D) SSFP MR scan with IR preparation to acquire systolic whole-heart anatomy for vein visualization. Delayed contrast-enhanced MR scan was performed to assess myocardial scar. CVA obtained by CMR was compared with X-ray venography in 11 patients. CVA and scar were segmented and registered for visual inspection. Results For all subjects, there was excellent visualization of the CVA. All ICM and one non-ICM patient showed scar. There was excellent correlation between veins seen by CMR and venography. Conclusion We have demonstrated that slow infusion protocol of dimeglumine-gadobenate can be used to assess both CVA and myocardial scar in a single MR examination. Furthermore, an image overlay technique has been used to show the relationship of scar to the CVA. J. Magn. Reson. Imaging 2011;33:87–95. © 2010 Wiley-Liss, Inc.

First-pass contrast-enhanced myocardial perfusion MRI in rodents has so far not been possible due to the temporal and spatial resolution requirements. We developed a new first-pass perfusion MR method for rodent imaging on a clinical 3.0-T scanner (Philips Healthcare, Best, The Netherlands) that employed 10-fold k-space and time domain undersampling with constrained image reconstruction, using temporal basis sets (k-t principle component analysis) to achieve a spatial resolution of 0.2 × 0.2 × 1.5mm3 and an acquisition window of 43 msec. The method was successfully tested in five healthy and four infarcted mice (C57BL/6J) at heart rates of 495.1 ± 45.8 beats/min. Signal-intensity-time profiles showed a percentage myocardial signal increase of 141.3 ± 38.9% in normal mice, compared with 44.7 ± 32.4% in infarcted segments. Mean myocardial blood flow by Fermi function for constrained deconvolution in control mice was 7.3 ± 1.5 mL/g/min, comparable to published literature, with no significant differences between three myocardial segments. In infarcted segments, myocardial blood flow was significantly reduced to 1.2 ± 0.8 mL/g/min (P < 0.01). This is the first report of first-pass myocardial perfusion MR in a mouse model on a clinical 3-T MR scanner and using a k-t undersampling method. Data were acquired on a 3-T scanner, using an approach similar to clinical acquisition protocols, thus facilitating translation of imaging findings between rodent and human studies. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.

Magnetic resonance angiography has evolved into a robust clinical tool, with improved performance of both hardware and software. However, the poor signal-to-noise ratio remains an important physical limitation. T1-shortening contrast agents help increase the signal-to-noise-ratio but conventional extracellular agents can be injected only in a limited dosage and this is followed by a rapid decrease in blood concentration caused by redistribution in the extracellular space. Gadofosveset trisodium offers a net increase in T1 relaxivity, blood-pool distribution and a longer half-life, promising to significantly improve magnetic resonance angiography image quality once again.

Myocardial perfusion MRI is acquired with a T1-weighted dynamic MRI sequence. Fully quantitative analysis of myocardial perfusion MRI allows the absolute quantification of myocardial blood flow (MBF) through the use of complex mathematical modeling. There are essentially two main methods for quantification of absolute MBF: the linear time-invariant model and the compartment model. Maximized contrast-to-noise ratio and the reasonable linearity of signal intensity in blood and myocardium are crucial for the accuracy of absolute MBF quantification by MRI. Quantitative assessment of MBF permits an accurate and objective assessment of myocardial perfusion and perfusion reserve in patients. This is of particular significance in patients with coronary artery disease but will also provide a means for investigating globally altered MBF in patients with microvascular disease of the heart. Furthermore, quantification of MBF with magnetic resonance can provides us with an important tool for monitoring disease progression and measuring the response to therapeutic interventions.

Cardiac stress magnetic resonance (MR) testing has been developed and optimized in the past decade, reaching a high diagnostic performance. Its efficacy, together with its excellent safety profile and increasing availability, make cardiac stress MR testing one of the diagnostic modalities of choice for detecting ischemia. A noticeable series of studies validated the diagnosis of ischemia with MR compared with coronary angiography and other noninvasive diagnostic techniques and invasive hemodynamic measurements. In addition, first data on the usefulness of cardiac stress MR testing in assessing prognosis has become available. This article reviews the available literature about diagnostic performance of cardiac stress MR testing and its results in the prognostication of cardiac patients.

Objectives To evaluate in vivo anatomical relationships between the coronary sinus–great cardiac vein (CS–GCV), the mitral valve annulus (MVA), and left circumflex coronary artery (LCX) with cardiovascular magnetic resonance. Background The CS–GCV has become an anatomical structure of interest because it provides a way of access to the heart for a number of interventional procedures. Previous reports demonstrate that the postulated close anatomical proximity of the CS–GCV to the MVA does not always hold true in patients, both in autopsy specimens and in vivo by computed tomography. Methods In 31 participants (24 volunteers and 7 patients; 15 men; 42 ± 19 years), cardiovascular magnetic resonance was performed for noninvasive evaluation of the coronary sinus and of the coronary arteries using whole-heart imaging and intravascular contrast agents. Three-dimensional reconstructions, standard orthogonal planes, and unprocessed raw data were used to assess CS–GCV anatomy and its relation to the MVA and the LCX along their entire course. Results The CS–GCV was located behind the left atrium in all examined participants, at a minimum distance of 8.6 ± 3.9 mm from the MVA. In 80% of the participants, the LCX crossed the CS–GCV inferiorly, between the CS–GCV and the MVA. The CS–GCV and the LCX had a parallel course for 26.2 ± 23.0 mm, with great variability of location and length. In several participants, the CS–GCV had a long parallel course, but in other participants, the LCX crossed below the CS–GCV at a discrete point. Conclusions In all participants, the CS–GCV coursed behind the left atrium rather than behind the MVA. In the majority of the participants, the LCX coursed between the CS–GCV and the MVA. These anatomical relationships should be kept in mind when referring a patient for interventional procedures requiring the access to the CS–GCV, and cardiovascular magnetic resonance might provide important information for the selection of candidates for these procedures.

Associated symptoms and conduction disturbances are reported during acute inferior myocardial infarction. Differentiation of right coronary artery from left circumflex artery occlusion may be difficult since both can present an electrocardiographic pattern of inferior myocardial infarction. Paroxysmal atrial fibrillation is considered a frequent complication of acute myocardial infarction and the patients with paroxysmal atrial fibrillation probably should be targeted for earlier and more aggressive treatment. These patients in the thrombolytic era have a better overall outcome than counterparts in the prethrombolytic era. We describe a case of conduction disturbances and paroxysmal atrial fibrillation in a 51-year-old Italian man with acute inferior myocardial infarction and right coronary artery stenosis.

Many heart failure patients with dyssynchrony do not reverse remodel (RR) in response to cardiac resynchronization therapy (CRT). The presence of focal and diffuse interstitial myocardial fibrosis may explain this high nonresponse rate. T1 mapping is a new cardiac magnetic resonance imaging (CMR) technique that overcomes the limitations of conventional contrast CMR and provides reliable quantitative assessment of diffuse myocardial fibrosis. The study tested the hypothesis that focal and diffuse fibrosis quantification would correlate with a lack of left ventricular (LV) RR to CRT.In a prospective study of 48 consecutive patients (27 ischemic cardiomyopathy, 21 dilated cardiomyopathy) LV scar burdens were quantified (scar core and gray zone using late gadolinium enhancement LGE CMR; interstitial fibrosis using T1 mapping) before CRT implant. LV RR was defined by a ≥ 15% reduction in LV end-systolic volume 6 months postimplant. Twenty-seven (56%) patients were responders with RR. Association between scar quantification and LV RR was assessed using the Poisson regression model. Univariate analysis showed that QRS duration/morphology, scar core, and gray zone volumes expressed as % of LV mass and extracellular volume index (ECV) (a measure of interstitial fibrosis from T1 mapping) to be significant predictors of LV RR. Multivariable-adjusted analyses demonstrated scar core quantification (≥ 13.7% LV mass) to be the only independent predictor of LV RR (prevalence ratio 0.40, P = 0.038).Focal scar burden detected by LGE CMR is associated with a poor response to CRT. Diffuse interstitial fibrosis assessment by T1 mapping, however, is not independently predictive of CRT response.

To determine the inter-study reproducibility of MR feature tracking (MR-FT) derived left ventricular (LV) torsion and torsion rates for a combined assessment of systolic and diastolic myocardial function.Steady-state free precession (SSFP) cine LV short-axis stacks were acquired at 9:00 (Exam A), 9:30 (Exam B), and 14:00 (Exam C) in 16 healthy volunteers at 3 Tesla. SSFP images were analyzed offline using MR-FT to assess rotational displacement in apical and basal slices. Global peak torsion, peak systolic and peak diastolic torsion rates were calculated using different definitions ("twist", "normalized twist" and "circumferential-longitudinal (CL) shear angle"). Exam A and B were compared to assess the inter-study reproducibility. Morning and afternoon scans were compared to address possible diurnal variation.The different methods showed good inter-study reproducibility for global peak torsion (intraclass correlation coefficient [ICC]: 0.90-0.92; coefficient of variation [CoV]: 19.0-20.3%) and global peak systolic torsion rate (ICC: 0.82-0.84; CoV: 25.9-29.0%). Conversely, global peak diastolic torsion rate showed little inter-study reproducibility (ICC: 0.34-0.47; CoV: 40.8-45.5%). Global peak torsion as determined by the CL shear angle showed the best inter-study reproducibility (ICC: 0.90;CoV: 19.0%). MR-FT results were not measurably affected by diurnal variation between morning and afternoon scans (CL shear angle: 4.8 ± 1.4°, 4.8 ± 1.5°, and 4.1 ± 1.6° for Exam A, B, and C, respectively; P = 0.21).MR-FT based derivation of myocardial peak torsion and peak systolic torsion rate has high inter-study reproducibility as opposed to peak diastolic torsion rate. The CL shear angle was the most reproducible parameter independently of cardiac anatomy and may develop into a robust tool to quantify cardiac rotational mechanics in longitudinal MR-FT patient studies.

Background Cardiovascular Magnetic Resonance myocardial feature tracking (CMR-FT) is a quantitative technique tracking tissue voxel motion on standard steady-state free precession (SSFP) cine images to assess ventricular myocardial deformation. The importance of left atrial (LA) deformation assessment is increasingly recognized and can be assessed with echocardiographic speckle tracking. However atrial deformation quantification has never previously been demonstrated with CMR. We sought to determine the feasibility and reproducibility of CMR-FT for quantitative LA strain and strain rate (SR) analysis.

Background Following myocardial infarction (MI), patients are at risk of sudden cardiac death (SCD) due to ventricular arrhythmia, which can be prevented with an implantable cardioverter-defibrillator (ICD). Recommendations for ICD implantation is currently based on left ventricular ejection fraction (LVEF), however less than a quarter of patients who receive ICDs based on LVEF have appropriate therapy. Heterogeneity of scar has been implicated in the development of re-entrant arrhythmias and SCD. Texture analysis (TA) is a method of quantifying heterogeneity of tissues in imaging, usually using statistical-based methods to evaluate distribution of grey-level pixels. This study aimed to determine whether TA could be used to quantify heterogeneity of scar as a method of accurately risk stratifying patients. Methods This was a retrospective blinded analysis of late-gadolinium enhanced cardiac magnetic resonance (LGE-CMR) images. Twenty post-MI patients who received ICDs were followed up for up to 686 days after implantation. Ten of these patients went on to have events and were categorised as high risk, while the remaining ten had no events on follow up and were categorised as low risk. TA was performed on regions of interest delineating

Background Cardiovascular magnetic resonance (CMR) offers quantification of phasic atrial functions based on volumetric assessment and more recently, on CMR feature tracking (CMR-FT) quantitative strain and strain rate (SR) deformation imaging. Inter-study reproducibility is a key requirement for longitudinal studies but has not been defined for CMR-based quantification of left atrial (LA) and right atrial (RA) dynamics. Methods Long-axis 2- and 4-chamber cine images were acquired at 9:00 (Exam A), 9:30 (Exam B) and 14:00 (Exam C) in 16 healthy volunteers. LA and RA reservoir, conduit and contractile booster pump functions were quantified by volumetric indexes as derived from fractional volume changes and by strain and SR as derived from CMR-FT. Exam A and B were compared to assess the inter-study reproducibility. Morning and afternoon scans were compared to address possible diurnal variation of atrial function. Results Inter-study reproducibility was within acceptable limits for all LA and RA volumetric, strain and SR parameters. Inter-study reproducibility was better for volumetric indexes and strain than for SR parameters and better for LA than for RA dynamics. For the LA, reservoir function showed the best reproducibility (intraclass correlation coefficient (ICC) 0.94–0.97, coefficient of variation (CoV) 4.5–8.2 %), followed by conduit (ICC 0.78–0.97, CoV 8.2–18.5 %) and booster pump function (ICC 0.71–0.95, CoV 18.3–22.7). Similarly, for the RA, reproducibility was best for reservoir function (ICC 0.76–0.96, CoV 7.5–24.0 %) followed by conduit (ICC 0.67–0.91, CoV 13.9–35.9) and booster pump function (ICC 0.73–0.90, CoV 19.4–32.3). Atrial dynamics were not measurably affected by diurnal variation between morning and afternoon scans. Conclusions Inter-study reproducibility for CMR-based derivation of LA and RA functions is acceptable using either volumetric, strain or SR parameters with LA function showing higher reproducibility than RA function assessment. Amongst the different functional components, reservoir function is most reproducibly assessed by either technique followed by conduit and booster pump function, which needs to be considered in future longitudinal research studies.

BACKGROUND: Cardiac magnetic resonance (CMR) is playing an expanding role in the assessment of patients with heart failure (HF). The assessment of myocardial perfusion status in HF can be challenging due to left ventricular (LV) remodelling and wall thinning, coexistent scar and respiratory artefacts. The aim of this study was to assess the feasibility of quantitative CMR myocardial perfusion analysis in patients with HF.METHODS: A group of 58 patients with heart failure (HF; left ventricular ejection fraction, LVEF ≤ 50%) and 33 patients with normal LVEF (LVEF >50%), referred for suspected coronary artery disease, were studied. All subjects underwent quantitative first-pass stress perfusion imaging using adenosine according to standard acquisition protocols. The feasibility of quantitative perfusion analysis was then assessed using high-resolution, 3 T kt perfusion and voxel-wise Fermi deconvolution.RESULTS: 30/58 (52%) subjects in the HF group had underlying ischaemic aetiology. Perfusion abnormalities were seen amongst patients with ischaemic HF and patients with normal LV function. No regional perfusion defect was observed in the non-ischaemic HF group. Good agreement was found between visual and quantitative analysis across all groups. Absolute stress perfusion rate, myocardial perfusion reserve (MPR) and endocardial-epicardial MPR ratio identified areas with abnormal perfusion in the ischaemic HF group (p = 0.02; p = 0.04; p = 0.02, respectively). In the Normal LV group, MPR and endocardial-epicardial MPR ratio were able to distinguish between normal and abnormal segments (p = 0.04; p = 0.02 respectively). No significant differences of absolute stress perfusion rate or MPR were observed comparing visually normal segments amongst groups.CONCLUSIONS: Our results demonstrate the feasibility of high-resolution voxel-wise perfusion assessment in patients with HF.

Background Patients with ischaemic heart disease (IHD) often show a combination of inducible ischaemia and previous myocardial infarction, therefore is particularly relevant to reach an accurate assessment of myocardial viability and ischaemic burden, as this may results in more appropriate therapy and better outcome. Areas of scar frequently result in false-positive perfusion findings, we therefore hypothesised that combined cardiac magnetic resonance (CMR) high-resolution quantitative perfusion and late gadolinium enhancement (LGE) protocol will result in a more accurate evaluation of ischaemic burden, avoiding areas of scar. Methods 15 patients with IHD and ejection fraction (EF)

A 59-year-old male experienced severe central chest pain for 1 hour with no associated breathlessness. His medical history included rheumatoid arthritis for which he took methotrexate. His 12 lead electrocardiogram confirmed sinus rhythm with a heart rate of 68 bpm, Q waves in the inferior leads and persisting ST segment elevation in leads V3–V6. Blood tests confirmed increased troponin and an echocardiogram confirmed severely impaired left ventricle function. Angiography noted an occluded right coronary artery with plaque in the left anterior descending artery but no targets for …

In some pathophysiological conditions myocardial metabolism can switch from mainly long chain fatty acid (LCFA) oxidation to mainly glucose oxidation. Whether the predominant fatty acid or glucose oxidation affects cardiac performance has not been defined. In a buffer perfused isovolumetrically contracting rat heart, oxidation of endogenous pool LCFA was avoided by inhibiting carnitine-palmitoyl-transferase I (CPT-I) with oxfenicine (2 mM). In order to restore fatty acid oxidation, hexanoate (1 mM), which bypasses CPT-I inhibition, was added to the perfusate. Three groups of hearts were subjected to either an increase in left ventricular volume (VV, +25%) or an increase in coronary flow (CF, +50%), or inotropic stimulation with isoproterenol (10(-8) and 10(-6) m). The increase in VV (the Frank-Starling mechanism) increased rate-pressure product (RPP) by 21 +/- 2% under control conditions, but only by 6 +/- 2% during oxfenicine-induced CPT-I inhibition. The contractile response to changes in VV recovered after the addition of hexanoate. Similar results were obtained in hearts, in which an increase in CF was elicited (the Gregg phenomenon). Isoproterenol caused a similar increase in contractility regardless of the presence of oxfenicine or hexanoate. In all groups, a commensurate increase in oxygen consumption accompanied the increase in contractility. The fatty acid oxidation is necessary for an adequate contractile response of the isolated heart to increased pre-load or flow, whereas the inotropic response to adrenergic beta-receptor stimulation is insensitive to changes in substrate availability.

Cold air inhalation during exercise increases cardiac mortality. The pathophysiology remains unclear, but may reflect adverse changes in microvascular resistance. We compared the accuracy of two intra-coronary measures of microvascular resistance to predict microvascular dysfunction. We then used

Background Both 3D and high-­resolution 2D-­perfusion CMR accurately detect coronary artery disease (CAD). 3D provides whole-­heart coverage whereas 2D better detects sub-­endocardial ischaemia. We compared the diagnostic accuracy of both techniques to detect flow limiting CAD as measured by fractional flow reserve (FFR). We also investigated the relative accuracy of these tools in identifying prognostically significant myocardial ischaemic burden (MIB). Methods Patients with suspected angina underwent high spatial resolution 2D k-­t SENSE (3 slices, in-­plane spatial resolution 1.3 × 1.3×8 mm) and 3D k-­t PCA whole heart (12 slices, in plane spatial resolution 2.3 × 2.3×5 mm) myocardial perfusion CMR during adenosine stress in a single sitting. Invasive coronary angiography with FFR (for stenoses of 50-­80% severity visually) was performed in all patients prior to revascularisation. Perfusion defects were contoured using circleCVI software and MIB was calculated for both 2D and 3D-­CMR. The anatomical and functional BCIS-­1 Jeopardy Scores (BCIS-­JS) scores were calculated from the invasive angiograms. Results Forty-­seven patients were included in the analysis. Per-­patient sensitivity, specificity, diagnostic accuracy, PPV, and NPV in identifying flow-­limiting CAD were 76%, 100%, 85%, 100%, 72% for 2D and 69%, 89%, 77%, 91%, 64% for 3D perfusion CMR (AUC of 0.88 versus 0.79, p=0.27). In 24 patients with confirmed CAD, the MIB by 2D and 3D was 15.7 ±­ 8.6% and 19.6% ±­ 11.7% respectively (p=0.088), with a trend towards 3D underestimating MIB by a mean of 3.8% (Figure 1). In these patients, considering 2D as the gold standard, the diagnostic accuracy of 3D CMR, anatomical BCIS-­JS, and functional BCIS-­JS in identifying prognostically significant MIB was 79%, 75%, and 87.5% respectively. (See Figures 2 and 3 for case examples) Conclusion In this first head-­to-­head comparison with invasive angiography and FFR, high-­resolution 2D and whole-­heart 3D perfusion CMR had comparable diagnostic performance in detecting flow-­limiting CAD on a per–patient basis. Both 3D and functional BCIS-­JS identify prognostically significant MIB well as determined by 2D. 2D estimates of MIB tend to be higher than 3D, however both methods have limitations (resolution versus coverage). In this contest, superior resolution may satisfactorily offset the lack of myocardial coverage.