Journal of Cardiovascular Magnetic Resonance最新文献

Background: There is a growing interest in the development and application of mid-field (0.55T) for cardiovascular magnetic resonance (CMR), including flow imaging. However, aortic flow imaging at 0.55T has limited signal-to-noise ratio (SNR), especially in diastolic phases where there is reduced inflow-driven contrast for spoiled gradient recalled echo (GRE) sequences. The low SNR can limit the accuracy of flow and regurgitant fraction measurements.

Methods: In this work, we developed a two-dimensional phase contrast (PC) acquisition with balanced steady-state free precession (bSSFP), termed PC-SSFP, for flow imaging and quantification at 0.55T. This PC-SSFP approach precisely nulls the zeroth and first gradient moments at both the echo time (TE) and repetition time, except for the flow-encoded acquisition, for which the first gradient moment at the TE is determined by the velocity encoding. Our proposed sequence was tested in both phantoms and in healthy volunteers (n = 11), to measure aortic flow. In volunteers, both a breath-hold (bh) and a free-breathing (fb) protocol, with averaging to increase SNR, were obtained. Total flow, peak flow, cardiac output, and SNR were compared for PC-SSFP and PC-GRE. Stroke volumes were also measured and compared to planimetry method.

Results: In a phantom, SNR was significantly higher using PC-SSFP compared to PC-GRE (25.5 ± 9.6 vs 8.2 ± 2.9), and the velocity measurements agreed well (R = 1.00). In healthy subjects, for both bh and fb protocols, PC-SSFP measured accurate peak flow (fb: R = 0.99, bh: R = 0.96) and cardiac output (fb: R = 0.98, bh: R = 0.88), compared to PC-GRE, accurate stroke volume (fb: R = 0.94, bh: R = 0.97), compared to planimetry measurement, and offered constant high SNR (fb: 28 ± 9 vs 18 ± 6, bh: 24 ± 7 vs 11 ± 3) over the cardiac cycle in 11 subjects.

Conclusion: PC-SSFP is a more reliable evaluation tool for aortic flow quantification, when compared to the conventional PC-GRE method at 0.55T, providing higher SNR, and thus potentially more accurate flows.

Background: Myocardial strain is a more sensitive parameter for cardiac function evaluation than left ventricular ejection fraction (LVEF). This study aimed to assess the predictive value of left ventricular global longitudinal strain (LV-GLS) by feature tracking-cardiac magnetic resonance (FT-CMR) imaging in patients with known or suspected coronary artery disease (CAD) with preserved left ventricular systolic function.

Methods: This retrospective cohort analysis enrolled patients with known or suspected CAD who underwent cardiac magnetic resonance imaging from September 2017 to December 2019. LV-GLS was analyzed via feature-tracking analysis. Patients with LVEF <50% were excluded. The composite outcome comprised all-cause death, non-fatal myocardial infarction, and heart failure.

Results: There was a total of 2613 patients. Mean follow-up duration was 39.7 ± 13.9 months. During follow-up, 194 patients (7.4%) experienced a composite outcome. The best cutoff of LV-GLS in the prediction of composite outcome from receiver operating characteristics was -14.4%. Patients were classified into 2 groups according to the LV-GLS; 1489 (57.0%) had LV-GLS <-14.4% and 1124 (43.0%) had LV-GLS ≥-14.4%. Patients with LV-GLS ≥-14.4% had a significantly higher rate of composite outcome than LV-GLS <-14.4% patients (3.59 vs. 1.39 per 100 person-years, respectively; p < 0.001). Multivariable analysis showed that patients with LV-GLS ≥-14.4% had a significantly higher risk of experiencing a composite outcome event compared to global longitudinal strain <-14.4% patients (adjusted hazard ratio: 1.83, 95% confidence interval: 1.28-2.61; p = 0.001).

Conclusion: LV-GLS by FT-CMR was shown to be useful for predicting the prognosis of patients with known or suspected CAD with preserved left ventricular systolic function. LV-GLS -14.4% was the identified cutoff for prognostic determination.

Background: Quantitative myocardial tissue characterization with T₁ and T₂ parametric mapping can provide an accurate and complete assessment of tissue abnormalities across a broad range of cardiomyopathies. However, current clinical T₁ and T₂ mapping tools rely predominantly on two-dimensional (2D) breath-hold sequences. Clinical adoption of three-dimensional (3D) techniques is limited by long scan duration. The aim of this study is to develop and validate a time-efficient 3D free-breathing simultaneous T₁ and T₂ mapping sequence using multi-parametric SAturation-recovery and Variable-flip-Angle (mSAVA).

Methods: mSAVA acquires four volumes for simultaneous whole-heart T₁ and T₂ mapping. We validated mSAVA using simulations, phantoms, and in-vivo experiments at 3T in 11 healthy subjects and 11 patients with diverse cardiomyopathies. T₁ and T₂ values by mSAVA were compared with modified Look-Locker inversion recovery (MOLLI) and gradient and spin echo (GraSE), respectively. The clinical performance of mSAVA was evaluated against late gadolinium enhancement (LGE) imaging in patients.

Results: Phantom T₁ and T₂ by mSAVA showed a strong correlation to reference sequences (R² = 0.98 and 0.99). In-vivo imaging with an imaging resolution of 1.5 × 1.5 × 8 mm³ could be achieved. Myocardial T₁ and T₂ of healthy subjects by mSAVA were 1310 ± 46 and 44.6 ± 2.0 ms, respectively, with T₁ standard deviation higher than MOLLI (105 ± 12 vs 60 ± 16 ms) and T₂ standard deviation lower than GraSE (4.5 ± 0.8 vs 5.5 ± 1.0 ms). mSAVA T₁ and T₂ maps presented consistent findings in patients undergoing LGE. Myocardial T₁ and T₂ of all patients by mSAVA were 1421 ± 79 and 47.2 ± 3.3 ms, respectively.

Conclusion: mSAVA is a fast 3D technique promising for clinical whole-heart T₁ and T₂ mapping.

Background: Aortic wall shear stress (WSS) is a known predictor of ascending aortic growth in patients with a bicuspid aortic valve (BAV). The aim of this study was to study regional WSS and changes over time in BAV patients.

Methods: BAV patients and age-matched healthy controls underwent four-dimensional (4D) flow cardiovascular magnetic resonance (CMR). Regional, peak systolic ascending aortic WSS, aortic valve function, aortic stiffness measures, and aortic dimensions were assessed. In BAV patients, 4D flow CMR was repeated after 3 years of follow-up and both at baseline and follow-up computed tomography angiography (CTA) were acquired. Aortic growth (volume increase of ≥5%) was measured on CTA. Regional WSS differences within patients' aorta and WSS changes over time were analyzed using linear mixed-effect models and were associated with clinical parameters.

Results: Thirty BAV patients (aged 34 years [interquartile range (IQR) 25-41]) were included in the follow-up analysis. Additionally, another 16 BAV patients and 32 healthy controls (aged 33 years [IQR 28-48]) were included for other regional analyses. Magnitude, axial, and circumferential WSS increased over time (all p < 0.001) irrespective of aortic growth. The percentage of regions exposed to a magnitude WSS >95th percentile of healthy controls increased from 21% (baseline 506/2400 regions) to 31% (follow-up 734/2400 regions) (p < 0.001). WSS angle, a measure of helicity near the aortic wall, decreased during follow-up. Magnitude WSS changes over time were associated with systolic blood pressure, peak aortic valve velocity, aortic valve regurgitation fraction, aortic stiffness indexes, and normalized flow displacement (all p < 0.05).

Conclusion: An increase in regional WSS over time was observed in BAV patients, irrespective of aortic growth. The increasing WSSs, comprising a larger area of the aorta, warrant further research to investigate the possible predictive value for aortic dissection.

Background: The Plaque At RISK (PARISK) study demonstrated that patients with a carotid plaque with intraplaque hemorrhage (IPH) have an increased risk of recurrent ipsilateral ischemic cerebrovascular events. It was previously reported that symptomatic carotid plaques with IPH showed higher IPH signal intensity ratios (SIR) and larger IPH volumes than asymptomatic plaques. We explored whether IPH SIR and IPH volume are associated with future ipsilateral ischemic cerebrovascular events beyond the presence of IPH.

Methods: Transient ischemic attack and ischemic stroke patients with mild-to-moderate carotid stenosis and an ipsilateral IPH-positive carotid plaque (n = 89) from the PARISK study were included. The clinical endpoint was a new ipsilateral ischemic cerebrovascular event during 5 years of follow-up, while the imaging-based endpoint was a new ipsilateral brain infarct on brain magnetic resonance imaging (MRI) after 2 years (n = 69). Trained observers delineated IPH, a hyperintense region compared to surrounding muscle tissue on hyper T₁-weighted magnetic resonance images. The IPH SIR was the maximal signal intensity in the IPH region divided by the mean signal intensity of adjacent muscle tissue. The associations between IPH SIR or volume and the clinical and imaging-based endpoint were investigated using Cox proportional hazard models and logistic regression, respectively.

Results: During 5.1 (interquartile range: 3.1-5.6) years of follow-up, 21 ipsilateral cerebrovascular ischemic events were identified. Twelve new ipsilateral brain infarcts were identified on the 2-year neuro MRI. There was no association for IPH SIR or IPH volume with the clinical endpoint (hazard ratio (HR): 0.89 [95% confidence interval: 0.67-1.10] and HR: 0.91 [0.69-1.19] per 100-µL increase, respectively) nor with the imaging-based endpoint (odds ratio (OR): 1.04 [0.75-1.45] and OR: 1.21 [0.87-1.68] per 100-µL increase, respectively).

Conclusion: IPH SIR and IPH volume were not associated with future ipsilateral ischemic cerebrovascular events. Therefore, quantitative assessment of IPH of SIR and volume does not seem to provide additional value beyond the presence of IPH for stroke risk assessment.

Trial registration: The PARISK study was registered on ClinicalTrials.gov with ID NCT01208025 on September 21, 2010 (https://clinicaltrials.gov/study/NCT01208025).

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.

Background: Coronary artery wall contrast enhancement (CE) has been applied to non-invasive visualization of changes to the coronary artery wall in systemic lupus erythematosus (SLE). This study investigated the feasibility of quantifying CE to detect coronary involvement in IgG4-related disease (IgG4-RD), as well as the influence on disease activity assessment.

Methods: A total of 93 subjects (31 IgG4-RD; 29 SLE; 33 controls) were recruited in the study. Coronary artery wall imaging was performed in a 3.0 T MRI scanner. Serological markers and IgG4-RD Responder Index (IgG4-RD-RI) scores were collected for correlation analysis.

Results: Coronary wall CE was observed in 29 (94 %) IgG4-RD patients and 22 (76 %) SLE patients. Contrast-to-noise ratio (CNR) and total CE area were significantly higher in patient groups compared to controls (CNR: 6.1 ± 2.7 [IgG4-RD] v. 4.2 ± 2.3 [SLE] v. 1.9 ± 1.5 [control], P < 0.001; Total CE area: 3.0 [3.0-6.6] v. 1.7 [1.5-2.6] v. 0.3 [0.3-0.9], P < 0.001). In the IgG4-RD group, CNR and total CE area were correlated with the RI (CNR: r = 0.55, P = 0.002; total CE area: r = 0.39, P = 0.031). RI´ scored considering coronary involvement by CE, differed significantly from RI scored without consideration of CE (RI v. RI´: 15 ± 6 v. 16 ± 6, P < 0.001).

Conclusions: Visualization and quantification of CMR coronary CE by CNR and total CE area could be utilized to detect subclinical and clinical coronary wall involvement, which is prevalent in IgG4-RD. The potential inclusion of small and medium-sized vessel involvements in the assessment of disease activity in IgG4-RD is worthy of further investigation.

Background: There is conflicting evidence regarding the response to a fixed dose of regadenoson in patients with high body weight. The aim of this study was to evaluate the effectiveness of regadenoson in patients with varying body weights using novel quantitative cardiovascular magnetic resonance (CMR) perfusion parameters in addition to standard clinical markers.

Methods: Consecutive patients with typical angina and/or risk factors for coronary artery disease (N = 217) underwent regadenoson stress CMR perfusion imaging using a dual-sequence quantitative protocol with perfusion parameters generated from an artificial intelligence (AI)-based algorithm. CMR was performed on 1.5T scanners using a standard 0.4 mg injection of regadenoson. A cohort of consecutive patients undergoing adenosine stress perfusion (N = 218) was used as a control group.

Results: An inverse association of myocardial perfusion reserve and weight (mean decrease -0.05 per 10 kg increase, 95% confidence interval [CI] -0.009/-0.0001, P = 0.045) was noted in the regadenoson group but not in patients stressed with adenosine (P = 0.77). Adjusted logistic regression analysis revealed a 10 kg increase resulted in 36% increased odds for inadequate stress response (odds ratio [OR] = 1.36, 95% CI 1.10-1.69, P = 0.005). Moreover, a significant interaction (OR = 1.09, 95% CI 1.02-1.16, P = 0.012) between stressor type (regadenoson vs adenosine) and weight was noted. This was also confirmed in the propensity-matched subgroup (P = 0.024) and was not attenuated after adjustment (P = 0.041). Body surface area (BSA) (P = 0.006) but not body mass index (P = 0.055) was differentially associated with inadequate response conditional to the stressor used, and this association remained significant after adjustment for confounders (P = 0.025). Patients in the highest quartile of weight (>93 kg) or BSA (>2.06 m²) had substantially increased odds for inadequate response with regadenoson (OR = 8.19, 95% CI 2.04-32.97, P = 0.003 for increased weight and OR = 7.75, 95% CI 1.93-31.13, P = 0.004 for increased BSA). Both weight and BSA had excellent discriminative ability for inadequate regadenoson response (receiver operating characteristic area under curves 0.84 and 0.83, respectively).

Conclusion: Using quantitative perfusion CMR in patients undergoing pharmacological stress with regadenoson, we found an inverse relationship between patient weight and both clinical response and myocardial perfusion parameters. A fixed-dose bolus approach may not be adequate to induce maximal hyperemia in patients with increased weight. Weight-adjusted stressors, such as adenosine, may be considered instead in patients with body weight >93 kg and BSA >2.06 m².

Background: Exertional heatstroke (EHS) is increasingly common in young trained soldiers. However, prognostic markers in EHS patients remain unclear. The objective of this study was to evaluate cardiovascular magnetic resonance (CMR) feature tracking derived left ventricle (LV) strain as a biomarker for return to training (RTT) in trained soldiers with EHS.

Methods: Trained soldiers (participants) with EHS underwent CMR cine sequences between June 2020 and August 2023. Two-dimensional (2D) LV strain parameters were derived. At 3 months after index CMR, the participants with persistent cardiac symptoms including chest pain, dyspnea, palpitations, syncope, and recurrent heat-related illness were defined as non-RTT. Multivariable logistic regression analysis was used to develop a predictive RTT model. The performance of different models was compared using the area under curve (AUC).

Results: A total of 80 participants (median age, 21 years; interquartile range (IQR), 20-23 years) and 27 health controls (median age, 21 years; IQR, 20-22 years) were prospectively included. Of the 77 participants, 32 had persistent cardiac symptoms and were not able to RTT at 3 months follow-up after experiencing EHS. The 2D global longitudinal strain (GLS) was significantly impaired in EHS participants compared to the healthy control group (-15.8 ± 1.7% vs -16.9 ± 1.2%, P = 0.001), which also showed significant statistical differences between participants with RTT and non-RTT (-15.0 ± 3.5% vs -16.5 ± 1.4%, P < 0.001). 2D-GLS (≤ -15.0%) (odds ratio, 1.53; 95% confidence interval: 1.08, 2.17; P = 0.016) was an independent predictor for RTT even after adjusting known risk factors. 2D-GLS provided incremental prognostic value over the clinical model and conventional CMR parameters model (AUCs: 0.72 vs 0.88, P = 0.013; 0.79 vs 0.88, P = 0.023; respectively).

Conclusion: Two-dimensional global longitudinal strain (≤ -15.0%) is an incremental prognostic CMR biomarker to predict RTT in soldiers suffering from EHS.

Background: Cardiovascular magnetic resonance (CMR) has demonstrated excellent performance in the diagnosis of cardiac amyloidosis (CA). However, misdiagnosis occasionally occurs because the morphological and functional features of CA are non-specific. This study was performed to determine the value of non-contrast CMR T1ρ in the diagnosis of CA.

Methods: This prospective study included 45 patients with CA, 30 patients with hypertrophic cardiomyopathy (HCM), and 10 healthy controls (HCs). All participants underwent cine (whole heart), T1ρ mapping, pre- and post-contrast T1 mapping imaging (three slices), and late gadolinium enhancement using a 3T whole-body magnetic resonance imaging system. All participants underwent T1ρ at two spin-locking frequencies: 0 and 298 Hz. Extracellular volume (ECV) maps were obtained using pre- and post-contrast T1 maps. The myocardial T1ρ dispersion map, termed myocardial dispersion index (MDI), was also calculated. All parameters were measured in the left ventricular myocardial wall. Participants in the HC group were scanned twice on different days to assess the reproducibility of T1ρ measurements.

Results: Excellent reproducibility was observed upon evaluation of the coefficient of variation between two scans (T1ρ [298 Hz]: 3.1%; T1ρ [0 Hz], 2.5%). The ECV (HC: 27.4 ± 2.8% vs HCM: 32.6 ± 5.8% vs CA: 46 ± 8.9%; p < 0.0001), T1ρ [0 Hz] (HC: 35.8 ± 1.7 ms vs HCM: 40.0 ± 4.5 ms vs CA: 51.4 ± 4.4 ms; p < 0.0001) and T1ρ [298 Hz] (HC: 41.9 ± 1.6 ms vs HCM: 48.8 ± 6.2 ms vs CA: 54.4 ± 5.2 ms; p < 0.0001) progressively increased from the HC group to the HCM group, and then the CA group. The MDI progressively decreased from the HCM group to the HC group, and then the CA group (HCM: 8.8 ± 2.8 ms vs HC: 6.1 ± 0.9 ms vs CA: 3.4 ± 2.1 ms; p < 0.0001). For differential diagnosis, the combination of MDI and T1ρ [298 Hz] showed the greatest sensitivity (98.3%) and specificity (95.5%) between CA and HCM, compared with the native T1 and ECV.

Conclusion: The T1ρ and MDI approaches can be used as non-contrast CMR imaging biomarkers to improve the differential diagnosis of patients with CA.