Journal of Cardiovascular Magnetic Resonance最新文献

Background: Preclinical studies exploring the underlying mechanisms of elevated left ventricular (LV) chamber stiffness play a crucial role in developing new therapeutic strategies. However, there is a lack of systematic evaluation of imaging biomarkers of diastolic function against gold standard assessment of LV chamber stiffness in rodents. Therefore, we aimed to evaluate imaging biomarkers of diastolic function from cardiovascular magnetic resonance (CMR) and echocardiography in predicting the slope of the end-diastolic pressure-volume relationship (EDPVR) in rats.

Methods: Sprague Dawley rats with varying degrees of myocardial stiffness induced by aortic constriction (n=38) and healthy controls (n=9) underwent echocardiography and CMR at approximately 13 weeks post-operation. Imaging biomarkers of diastolic function were evaluated for their ability to predict the EDPVR slope from pressure-volume recordings using regression analysis and receiver operating characteristics analysis.

Results: Both CMR and echocardiographic imaging biomarkers, in particular those related to the left atrium and mitral flow, were able to predict the EDPVR slope in a rat model with varying stiffness. From CMR, native T1 values, peak early diastolic longitudinal strain rate (SRe(long)) and E/SRe(long), left atrial (LA) ejection fraction, isovolumetric relaxation time (IVRT), E/A and peak LA strain, correlated best with the EDPVR slope (|r|=0.54-0.72). From echocardiography, E/A, E, LA diameter, e'/a', E/SRe(long) and IVRT correlated with the EDPVR slope (|r|=0.49-0.67), while E/e', e' and E-wave deceleration time demonstrated poor correlation (|r|=0.17-0.27). Receiver operating characteristics analysis indicated better performance of CMR imaging biomarkers than echocardiography in predicting increased EDPVR slope.

Conclusions: Several diastolic imaging biomarkers commonly employed in preclinical studies have poor ability to predict cardiac chamber stiffness. Our study identifies several imaging biomarkers obtained from both echocardiography and CMR that are able to estimate LV chamber stiffness non-invasively, providing an important tool for future mechanistic research on myocardial stiffness.

Background: Patients presenting to the emergency department (ED) with chest pain often have abnormal high-sensitivity troponin (hsTn). However, only about 5% have an acute coronary syndrome. We aimed to assess the safety, feasibility, and utility of a clinical disposition protocol, including outpatient observation with stress cardiovascular magnetic resonance (CMR) in intermediate-risk patients with abnormal hsTn of unclear etiology.

Methods: Patients with abnormal hsTn and modified HEART-score ≤6 underwent CMR to inform diagnosis, risk stratification, and ED disposition. Patients were followed at 30 and 90 days for all-cause mortality, readmission for myocardial infarction, and unplanned coronary revascularization.

Results: CMR was completed in 50 patients (64 years, 56% male) at a median of 23.2 h after presentation to the ED. CMR findings of coronary artery disease (CAD) were present in 19 (38%, 19/50) of patients, of which 13 had known CAD and 6 received a new diagnosis of CAD. In 12 (24%, 12/50) patients, cardiac noncoronary artery disease was diagnosed [cardiomyopathy (8), valvular disease (3), and myocarditis/pericarditis (1)], of which the majority (83%) (10/12) were new diagnoses. CMR was normal in 19 (38%, 19/50) patients. After CMR results were reported, the decision to admit was made in 10 (20%, 10/50) patients, while 40 (80%, 40/50) were discharged from the ED without further cardiac testing. Follow-up was completed in 96% (48/50) of patients, of which no patients experienced an adverse event.

Conclusion: A disposition protocol with outpatient observation and stress CMR is feasible and useful for determining the etiology of myocardial injury and risk stratification in patients presenting to the ED with chest pain, abnormal hsTn, and intermediate risk.

Background: This study aims to identify optimal acceleration factors (AFs) for compressed sensing (CS) technology to enhance its clinical application for suspected coronary artery disease (CAD) in whole-heart non-contrast coronary magnetic resonance angiography (CMRA).

Methods: Two hundred and seventeen individuals with suspected CAD underwent whole-heart non-contrast CMRA on a 1.5T CMR scanner with CS AFs of 2, 4, and 6 (CS2, CS4, and CS6). Two radiologists independently and blindly scored the image quality. The overall image scores, coronary artery segment scores, signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR), and scan times were compared. The scores for the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and right coronary artery (RCA) were assessed. Of the 217 patients, 37 (37/217, 17.1%) underwent x-ray coronary angiography (CAG). The images from CS2, CS4, and CS6 were evaluated by two radiologists blinded to CAG results to identify significant luminal narrowing. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated.

Results: The CS2 group exhibited higher overall scores, coronary artery segment scores, SNR, and CNR, but longer scan times compared to the CS4 and CS6 groups (overall score: 24.5 vs 22.0 vs 21.0, p < 0.001; SNR: 127 vs 112 vs 99, p < 0.001; CNRcor-fat: 118 vs 101 vs 84, p < 0.001; CNRcor-myo: 69.7 vs 62.8 vs 53.5, p < 0.001; scan time: 884 ± 308 s vs 473 ± 163 s vs 331 ± 146 s, p < 0.001). Proximal and middle segments received higher scores compared to their corresponding distal segments, and the RCA exhibited higher image quality than LAD and LCX in all groups (p < 0.05). In the subgroup analysis, 19 (19/37, 51.3%) were diagnosed with CAD by CAG. The sensitivity, specificity, PPV, NPV, and accuracy were as follows: CS2 (94.7%, 88.9%, 90.0%, 94.1%, and 91.9%), CS4 (89.5%, 94.4%, 94.4%, 89.5%, and 91.9%), and CS6 (89.5%, 66.7%, 73.9%, 85.7%, and 78.4%), respectively, in patient-based analysis.

Conclusion: Image quality showed a decreasing trend with increasing CS AFs, while scan time decreased in non-contrast CMRA. A scanning protocol using CS4 provided high-quality images with relatively short scan times and showed potential for detecting significant coronary stenosis, making it an optimal protocol for coronary magnetic resonance imaging.

Objectives: To examine the provision of cardiovascular magnetic resonance (CMR) using gadolinium-based contrast agents (GBCA) in patients with chronic kidney disease (CKD).

Methods: An electronic survey was sent to the service leads of all CMR units in the UK in October 2022 requesting information on current departmental protocols and practices.

Results: A response rate of 55% was achieved from the 82 UK CMR units surveyed. There were no known cases of nephrogenic systemic fibrosis (NSF) reported within the past 10 years. Just under half the centers (22 out of 45, 49%) routinely require an estimated glomerular filtration rate (eGFR) in patients before performing contrast-enhanced CMR. Conversely, 18% (8/45) of units do not check eGFR, 20% (9/45) only require an eGFR in patients aged >65 years, while 33% (15/45) assess eGFR in patients known to have CKD. All centers use group II GBCAs: the majority (36/45, 80%) favoring gadobutrol (Gadovist), while gadoterate meglumine (Dotarem) is used in most of the remaining units (8/45, 18%). One in five centers (9/45, 20%) do not currently offer contrast-enhanced CMR to patients with an eGFR <30 mL/min/1.73 m². Of the CMR units that do offer contrast to this group of patients, 28% (10/36) do not obtain consent for the risk of NSF.

Conclusion: One in five centers across the UK does not offer contrast-enhanced CMR to patients with stage 4 and 5 CKD. This finding serves as a call for updated guidance with the intention of standardizing care.

Delivery of health care, including medical imaging, generates substantial global greenhouse gas emissions. The cardiovascular magnetic resonance (CMR) community has an opportunity to decrease our carbon footprint, mitigate the effects of the climate crisis, and develop resiliency to current and future impacts of climate change. The goal of this document is to review and recommend actions and strategies to allow for CMR operation with improved sustainability, including efficient CMR protocols and CMR imaging workflow strategies for reducing greenhouse gas emissions, energy, and waste, and to decrease reliance on finite resources, including helium and waterbody contamination by gadolinium-based contrast agents. The article also highlights the potential of artificial intelligence and new hardware concepts, such as low-helium and low-field CMR, in achieving these aims. Specific actions include powering down magnetic resonance imaging scanners overnight and when not in use, reducing low-value CMR, and implementing efficient, non-contrast, and abbreviated CMR protocols when feasible. Data on estimated energy and greenhouse gas savings are provided where it is available, and areas of future research are highlighted.

Background: Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) shows promise for quantifying mitral regurgitation (MR) by allowing for direct regurgitant volume (RVol) measurement using a plane precisely placed at the MR jet. However, the ideal location of a measurement plane remains unclear. This study aims to systematically examine how varying measurement locations affect RVol quantification and determine the optimal location using the momentum conservation principle of a free jet.

Methods: Patients diagnosed with MR by transthoracic echocardiography (TTE) and scheduled for CMR were prospectively recruited. Regurgitant jet flow volume (RVol_jet) and regurgitant jet flow momentum (RMom_jet) were quantified using 4D flow CMR at seven locations along the jet axis, x. The reference plane (mid-plane, x = 0 mm) was positioned at the peak velocity of the jet at each cardiac phase, and three additional planes were positioned on either side of the jet, each 2.5 mm apart. RVol_jet was compared to RVol_TTE, measured by the proximal isovelocity surface area method, and RVol_indirect, measured by subtracting aortic forward flow volume from the left ventricle stroke volume derived from two-dimensional phase contrast at the aortic valve and a stack of short-axis cine CMR techniques.

Results: RVol_jet and RMom_jet were quantified in 45 patients (age 63±13, male 26). In patients with RVol_jet at x = 0 mm ≥ 10 mL (n = 25), RVol_jet consistently increased as the plane moved downstream. RVol_jet measured furthest upstream (x = -7.5 mm) was significantly lower (39±11%, p<0.001) and RVol_jet measured furthest downstream (x = 7.5 mm) was significantly higher (16±19%, p<0.001) than RVol_jet at x = 0 mm. RMom_jet similarly increased from x = -7.5 to 0 mm (57±12%, p<0.001) but stabilized from x = 0-7.5 mm (-2±17%). From x = -7.5 to 7.5 mm, RVol_jet was in consistent moderate agreement with RVol_indirect (n = 41, bias = -2±24 to 8±32 mL, intraclass correlation coefficient = 0.55-0.63, p<0.001).

Conclusion: The location of a measurement plane significantly influences RVol quantification using the direct 4D flow CMR approach. Based on the converging profile of RMom_jet, we propose the peak velocity of the jet as the optimal position.

Background: To investigate image quality and agreement of derived cardiac function parameters in a novel joint image reconstruction and segmentation approach based on disentangled representation learning, enabling real-time cardiac cine imaging during free-breathing.

Methods: A multi-tasking neural network architecture, incorporating disentangled representation learning, was trained using simulated examinations based on data from a public repository along with cardiovascular magnetic resonance (CMR) scans specifically acquired for model development. An exploratory feasibility study evaluated the method on undersampled real-time acquisitions using an in-house developed spiral balanced steady-state free precession pulse sequence in eight healthy participants and five patients with intermittent atrial fibrillation. Images and predicted left ventricle segmentations were compared to the reference standard of electrocardiography (ECG)-gated segmented Cartesian cine with repeated breath-holds and corresponding manual segmentation.

Results: On a 5-point Likert scale, image quality of the real-time breath-hold approach and Cartesian cine was comparable in healthy participants (RT-BH: 1.99 ± 0.98, Cartesian: 1.94 ± 0.86, p = 0.052), but slightly inferior in free-breathing (RT-FB: 2.40 ± 0.98, p < 0.001). In patients with arrhythmia, both real-time approaches demonstrated favorable image quality (RT-BH: 2.10 ± 1.28, p < 0.001, RT-FB: 2.40 ± 1.13, p < 0.01, Cartesian: 2.68 ± 1.13). Intra-observer reliability was good (intraclass correlation coefficient = 0.77, 95% confidence interval [0.75, 0.79], p < 0.001). In functional analysis, a positive bias was observed for ejection fractions derived from the proposed model compared to the clinical reference standard (RT-BH mean: 58.5 ± 5.6%, bias: +3.47%, 95% confidence interval [-0.86, 7.79%], RT-FB mean: 57.9 ± 10.6%, bias: +1.45%, [-3.02, 5.91%], Cartesian mean: 54.9 ± 6.7%).

Conclusion: The introduced real-time CMR imaging technique enables high-quality cardiac cine data acquisitions in 1-2 min, eliminating the need for ECG gating and breath-holds. This approach offers a promising alternative to the current clinical practice of segmented acquisition, with shorter scan times, improved patient comfort, and increased robustness to arrhythmia and patient non-compliance.

Background and aims: Heart failure (HF) is an imminent global health problem. Yet established screening algorithms for asymptomatic pre-HF, allowing for early and effective preventive interventions, are largely lacking. The HERZCHECK trial, conducted in structurally underserved rural regions of North-Eastern Germany, aims to close this gap by evaluating the feasibility, diagnostic efficacy, and cost-effectiveness of a fully mobile, telemedically-supervised screening approach, combining cardiovascular magnetic resonance (CMR) imaging and laboratory testing as central elements.

Study design and methodology: The HERZCHECK trial is a prospective, randomized controlled trial employing a prospective randomized open blinded endpoint design. The study targets asymptomatic adults aged 40-69 years without a history of HF, but with at least one of the following cardiovascular risk factors: hypertension, hypercholesterolemia, obesity, smoking/tobacco consumption, chronic diabetes mellitus, or chronic kidney disease. Participants undergo a comprehensive screening examination including a questionnaire-based medical history, laboratory testing, and CMR at baseline. Based on CMR-derived global longitudinal strain (GLS), participants are classified as stratum A (GLS < -15%), B (GLS ≥ -15% to < -11%), or C (GLS ≥ -11%), with strata B and C being defined as asymptomatic pre-HF. Ten percent of participants in stratum A and all of stratum B and C are subsequently randomized into two groups, receiving either conventional or innovative medical reports, the latter including information on GLS, guideline-based recommendations, and access to a lifestyle intervention app for cardiovascular prevention. Additionally, treating physicians of participants in the innovative group are granted access to an expert center for telemedical inquiries. Follow-up assessments are performed over 12 months to evaluate changes in GLS, as well as adverse cardiac events and quality of life.

Conclusion: HERZCHECK aims to provide a blueprint for a comprehensive, contemporary screening approach tailored to the needs of the targeted structurally underserved population. By implementing this approach in a representative at-risk cohort, HERZCHECK will provide important new information about (a) the prevalence of asymptomatic pre-HF in at-risk patients and (b) the feasibility, added diagnostic value and health economic aspects of CMR exams as part of future screening mechanisms for HF in clinical routine care (NCT05122793).

Background: Patients after kidney transplantation (KTx) in childhood show a high prevalence of cardiac complications, but the underlying mechanism is still poorly understood. In adults, myocardial fibrosis detected in cardiovascular magnetic resonance (CMR) imaging is already an established risk factor. Data for children after KTx are not available. This study aimed to explore cardiac function and structure with focus on myocardial fibrosis and associated risk factors in KTx recipients.

Methods: Forty-six KTx recipients (mean age 16.0 ± 3.5 years) and 46 age- and sex-matched healthy controls were examined with non-contrast CMR imaging. Native T1 time (nT1), a marker for myocardial fibrosis, was measured at the interventricular septum. Other parameters comprised left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF), and global longitudinal strain (GLS). Multivariable linear regression analyses were used to explore associations with nT1.

Results: Mean nT1 was significantly higher in KTx recipients compared to controls (1198.1 ± 48.8 vs 1154.4 ± 23.4 ms, p < 0.0001). 46% (21/46) had a nT1 above the upper limit of the normal range (mean + 2 standard deviations of controls). KTx recipients showed higher LVMI z-scores (0.1 ± 1.1 vs -0.3 ± 0.7, p = 0.026), higher LVEF (67.3 ± 3.8% vs 65.3 ± 3.6%, p = 0.012), and lower GLS (-19.0 ± 2.1% vs -20.3 ± 2.7%, p = 0.010). Higher systolic blood pressure (ß = 1.284, p = 0.001), LVMI (ß = 1.542, p < 0.001), and LVEF (ß = 3.535, p = 0.026) were associated with longer nT1 only in KTx recipients, but not in controls. Only 2 KTx recipients exhibited left ventricular hypertrophy; however, a total of 18 displayed elevated nT1 with LVMI z-score within the normal range.

Conclusion: Our data suggest the presence of cardiac remodeling with myocardial fibrosis in a significant proportion of young KTx recipients. Non-contrast CMR imaging has the potential to visualize early structural cardiac changes and could become an important diagnostic adjunct in the follow-up of KTx recipients. Longitudinal studies are needed to further evaluate the importance of nT1 in early identification of those at high risk for sudden cardiac death allowing to integrate preventive strategies.