Journal of Cardiovascular Magnetic Resonance最新文献

Background: Although balanced steady-state free-precession (bSSFP) cines provide excellent contrast for morpho-functional cardiac evaluation, the fluctuating myocardial cine signal intensity (mcSI) is rarely used diagnostically. These mcSI fluctuations were related to through-plane motion but the impact of this motion remains unclear. We aim to characterize the mid-ventricular pre- and postcontrast bSSFP cyclic mcSI fluctuations in healthy subjects and compare these to Bloch simulations incorporating through-plane motion.

Methods: Retrospectively-gated mid-ventricular short-axis cine bSSFP images from healthy subjects (n = 49) acquired at 1.5T pre- and early postcontrast were analyzed. First, the mcSI fluctuations during the heart cycle were determined and their timing compared to the radial myocardial motion. Next, pre- vs postcontrast differences were determined during systole, early-diastole, and late-diastole. Finally, Bloch simulations and acquisitions in a moving T1 phantom were performed to analyze the through-plane motion effect on the bSSFP and spoiled gradient echo (SGRE) mcSI.

Results: The bSSFP mcSI showed a three-peak pattern both pre- and postcontrast, corresponding to the contraction and relaxation phases. However, the mcSI peaks showed a time lag vs the times of maximum radial velocity that was larger for the systolic contraction than for the early or late-diastolic relaxation phases. In addition, the shape and amplitude of the systolic and early diastolic mcSI peaks changed significantly post- vs precontrast. Bloch simulations showed an in-vivo-like (regional) three-peak signal profile and similar changes for post- vs precontrast T1 levels. Finally, results in the moving phantom and accompanying simulations confirmed a slice-thickness-dependent time lag between the motion and mcSI profile in both bSSFP and SGRE.

Conclusion: In healthy subjects before and after contrast, the bSSFP mcSI variation during the heart cycle is characterized by a three-peak pattern associated with the contraction and relaxation phases. However, the delays in timing of these peaks vs the myocardial motion, as well as the differences between pre- and postcontrast, vary with the stage of the heart cycle. Bloch simulations suggest that these mcSI fluctuations are largely determined by the regional through-slice motion. A better understanding of these motion-induced contrast mechanisms may be beneficial to methods exploiting bSSFP mcSI.

Background: Late gadolinium enhancement imaging is the cornerstone of tissue characterization via cardiac magnetic resonance imaging. The contrast-enhancing effect of gadolinium is caused by a linear increase in tissue longitudinal R1 relaxation rates (R1 = 1/T1). The change in R1 of blood pre- and post-contrast (ΔR1_blood) is therefore a surrogate for the blood-pool gadolinium concentration, which in turn correlates linearly to the tissue gadolinium concentration. The total volume of distribution for gadolinium is the extracellular volume of the body, which differs with body composition, potentially leading to variations in blood-pool and tissue gadolinium concentrations.

Methods: This study is a hypothesis-generating secondary analysis of a dataset of 1098 patients who underwent contrast cardiovascular magnetic resonance between August 2014 and November 2020 at a tertiary center. ΔR1_blood was calculated from T1 relaxation time maps acquired before and approximately 15 min after application of 0.15 mmol/kg gadobutrol. Explorative data analysis and multiple linear regression were performed to assess the influence of body mass index (BMI), gender, age, cardiac index (CI), hematocrit (Hct), and left ventricular end-diastolic volume index (LVEDVi) on ΔR1_blood.

Results: In bivariate analysis, ΔR1_blood showed moderate correlation to BMI and weak correlation to LVEDVi, Hct, and CI. The correlation to BMI was higher in women (r = 0.52 at 1.5T and r = 0.47 at 3T) than in men (r = 0.27 at 1.5T and r = 0.37 at 3T). Multiple linear regression showed independent predictive value of BMI, BMI:gender, gender, CI, field strength (FS), and LVEDVi (R² = 0.268, P < 0.001), with BMI remaining the strongest individual predictor (b = 0.032 [0.025; 0.040], η² = 0.13, P < 0.001).

Conclusion: ΔR1_blood, a measurement of gadolinium contrast enhancement in the blood-pool and a surrogate of plasma C_Gd at the time of late enhancement imaging, showed moderate association with BMI, FS, and gender and weak association with LVEDVi and CI. Further research is necessary to assess the need for individualized gadolinium dosing.

Background: Exercise electrocardiogram (ECG) remains widely performed in the assessment of patients with suspected cardiac chest pain. We aimed to assess the comparative diagnostic and prognostic yield of exercise ECG, single photon emission computed tomography (SPECT), and cardiovascular magnetic resonance (CMR), in a large prospective patient population.

Methods: Patients recruited to Clinical Evaluation of MAgnetic Resonance in Coronary heart disease (CE-MARC) who had exercise ECG were included and followed up to a median (interquartile range) of 6.3 (0.1, 6.8) years. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) for diagnostic accuracy were derived and hazard ratios of major adverse cardiovascular events (MACE) for prognostic significance were calculated.

Results: Of 752 patients in the CE-MARC trial, 580 had exercise ECG and invasive coronary angiography, of which 503 also had SPECT and CMR. At follow-up, a total of 91 (15.7%) patients experienced MACE. Using invasive angiography as the reference test, the sensitivity, specificity, PPV, and NPV (95% confidence interval) of exercise ECG were 68.3 (61.9, 74.0), 72.5 (67.6, 76.9), 61.0 (54.8, 66.8), 78.4 (73.7, 82.5). Exercise ECG was significantly less sensitive than CMR and less specific than both CMR and SPECT. A positive exercise ECG result was not predictive of MACE at follow-up (Hazard ratio 1.14 [0.75, 1.72], p = 0.53). CMR had both a greater diagnostic and prognostic yield than exercise ECG, SPECT, and their combination. Sequential CMR following inconclusive exercise ECG was comparable to CMR alone as the first-line test.

Conclusion: In patients with suspected angina, CMR alone as the first-line test was more sensitive and prognostically accurate than exercise ECG, SPECT, or sequential combination of both tests.

Background: Magnetic resonance imaging (MRI) with displacement encoding with stimulated echoes (DENSE) is well recognized for accurate and precise quantification of myocardial displacement and strain, but its reproducibility before and after contrast injection has not been investigated. Gadolinium is the most widely used contrast agent. Ferumoxytol is increasingly used off-label in specific patient groups. We aim to assess the reproducibility of cine DENSE MRI to measure global and segmental circumferential myocardial strain (E_CC) before and after contrast injection for gadolinium and ferumoxytol, respectively.

Methods: All imaging was conducted using 3T scanners. In 11 patients with cardiac disease, breath-hold two-dimensional cine DENSE was acquired in a mid-ventricular short-axis slice before and following the injection of gadolinium (0.1 mmol/kg). A separate cohort of 11 subjects (5 healthy subjects and 6 patients with ischemic heart disease) received 3 incremental doses of ferumoxytol: 0.125, 1.875, and 2.0 mg/kg (to a cumulative dose of 4.0 mg/kg). The same DENSE acquisition was performed before and after each incremental dose. Post-processing generated left ventricular (LV) displacement and E_CC maps, and strain-time curves. Global and segmental E_CC in six mid-level short-axis LV segments were compared. Signal-to-noise (SNR) was evaluated on the magnitude images throughout the cardiac cycle in the myocardium, liver, and back muscle, respectively. A Bayesian analysis was performed to test results with region of practical equivalence (ROPE) at ±5 for SNR and ±0.02 for E_CC (p < 0.05 as significant).

Results: Based on the percentage within the ROPE and the corresponding p-values, global E_CC exhibited excellent practical equivalence under pre- and post-contrast conditions for gadolinium (p = 0.413) and ferumoxytol (p ≥ 0.161). Segmental E_CC reproducibility was consistently high across all comparative analyses, with at least 87.02% falling within the ROPE. Gadolinium administration significantly improved SNR in all tissues during the early systolic phases (1-5, p ≤ 0.021). Ferumoxytol resulted in a reduction in liver SNR during diastolic phases (10-20, p ≤ 0.011) and a significant increase in myocardium SNR during systolic phases (1-5, p ≤ 0.034).

Conclusion: Good reproducibility of global and segmental E_CC measurements using cine DENSE before and after contrast injection is achievable at 3T.

Background: False-negative cardiovascular magnetic resonance (CMR) perfusion results may arise from inadequate stress responses, even when patients exhibit an adequate clinical or heart-rate response to adenosine. This study aimed to explore the ability of qualitative and quantitative splenic switch-off (SSO) markers to differentiate true-negative from potentially false-negative adenosine stress-perfusion CMR findings in a cohort where fractional flow reserve (FFR) was used to adjudicate lesion significance.

Methods: Patients with known or suspected coronary artery disease (CAD) from five centers underwent three-dimensional (3D) adenosine stress perfusion CMR and coronary angiography with FFR. SSO was assessed qualitatively using both standard stress-to-rest (SSO) and a stress-only (SSO_stress) approach. In addition, quantitative signal intensity (SI) ratios were assessed, including the splenic stress-to-rest SI-ratio (SI_stress/rest) and the spleen-to-myocardium SI ratio at stress (SI_{spleen/myocarcium}). The diagnostic accuracy of these measures was evaluated using cross-validated area under the curve (cvAUC) analysis.

Results: Among 179 patients (mean age 63 ± 10 years; 130 male), SSO prevalence was 73% (130/179) and was significantly more frequent in true-negative than false-negative CMR cases (80.6% [54/67] vs 36.8% [7/19], p < 0.001). SSO_stress showed moderate agreement (κ = 0.60) and robust diagnostic performance (AUC 0.80), as compared to SSO. Splenic SI_stress/rest and SI_{spleen/myocarcium} at stress demonstrated high predictive accuracy for visual SSO, with cvAUCs of 0.94 (95% CI: 0.90-0.96) and 0.90 (95% CI: 0.86-0.95), respectively. The positive likelihood ratio of SSO for true-negative CMR was 1.70, while the negative likelihood ratio was 0.24. Qualitative and quantitative splenic-switch off metrics classified 77%-80% (66-69/86) of negative CMR cases correctly as true- or potentially false-negatives, with sensitivities ranging from 81.4% to 91.2%. Clinically applicable cut-offs for differentiating true- and false-negative studies with splenic SI_stress/rest and SI_{spleen/myocarcium} at stress were identified as ≤0.32 and ≤0.38, respectively.

Conclusion: In a multicenter cohort using FFR-adjudicated reference for lesion severity, qualitative SSO and quantitative SI metrics were associated with myocardial stress adequacy and these markers may improve the interpretation of negative stress-perfusion CMR studies.

Background: Normal reference ranges in cardiovascular imaging studies are typically established as the mean value plus and minus twice the standard deviation (SD) of a healthy reference cohort ("2 SD-method"). Although widely used for cardiac magnetic resonance (CMR), this approach has not been previously validated. The purpose of this study was to use longitudinal cohort data to assess the clinical predictive validity of normal reference values for cardiac CMR.

Methods: Normal reference ranges for left- and right ventricular (LV and RV) CMR parameters were derived from baseline exam data of 1518 participants (age 45-84years) in the Multi-Ethnic Study of Atherosclerosis (MESA) study without known CV disease and without established CV risk factors. Cut-off values at 1 and 2 SDs were obtained for the following LV and RV parameters indexed to body surface area: end-diastolic volume (LVEDVi, RVEDVi), end-systolic volume (LVESVi, RVESVi), mass (LVMi, RVMi), as well as for LVED diameter (LVEDD), LVED wall thickness, and ejection fraction (LVEF, RVEF). The relationship of reference values to CV events was then evaluated in the entire MESA cohort with CMR data (n=4915), including individuals with CV risk factors at the baseline exam. Cox proportional hazard models were calculated for major adverse and all CV events (MACE and ACE, respectively) at 5 and 10 years of follow-up.

Results: At 5 years of follow-up, LVEDVi, LVESVi, and LVEF beyond the 2SD-threshold of the mean reference values were predictors of MACE and ACE in men and women (HR 2.1-4.3; P<.001-.029). In men, LVMi and LVED wall thickness above the 1 SD-threshold were associated with CV events (HR 1.6-2.1; P<.001-.002). For women, LVED wall thickness above the 1 SD-threshold significantly increased risk of adverse events (HR 1.6-2.3; P.034-.002) while LVMi was associated with events only for values above the 2SD-threshold (HR 2.7-4.1; P<.001). Notably, LVEDD, RVMi, RVESVi, and RVEF were not associated with CV events in men or women. CV events over 10 years showed similar trends.

Conclusion: Our results support the clinical relevance of CMR normal reference ranges for LV parameters. Most LV CMR parameters beyond the normal reference range (2SD-threshold) were associated with elevated CV risk at 5 and 10 years. Elevated LVEDDi, RVMi, RVESVi, and RVEF, however, were not associated with CV events.

Background: Although a recently developed wideband perfusion sequence has shown diagnostically acceptable image quality and accurate myocardial blood flow (MBF) quantification at rest in patients with cardiac implanted electronic devices, its performance during vasodilator stress remains unproven. This study aims to determine whether the sequence produces diagnostically acceptable image quality during stress and is capable of quantitatively detecting abnormal stress MBF and myocardial perfusion reserve (MPR) in patients with implanted cardiodefibrillators (ICDs).

Methods: We enrolled 29 patients with an ICD (mean age=63±15years, 17 males, 12 females) and 11 control patients (mean age=50±17years, 6 males, 5 females; negative coronary artery disease; negative stress perfusion CMR; and no cardiac event one year post CMR) with an ICD taped below the left clavicle to mimic image artifacts. Both groups underwent imaging using a six-fold accelerated wideband perfusion sequence during adenosine stress and at rest. Images were reconstructed using a compressed sensing framework. Two clinical readers independently graded the following three categories on a 5-point Likert scale (1: worst, 3: clinically acceptable, 5: best): conspicuity of wall enhancement, noise, and artifact. Pixel-wise stress-rest MBF maps were quantified for both global and segmental analysis. MPR was calculated as the ratio of mean stress to rest MBFs.

Results: The median summed visual score was above the acceptable cut-point (>9.0) and not significantly different between the two groups. Both mean global and segmental stress MBF and MPR were significantly lower (p<0.05) in the ICD patient group (global MBF=1.79±0.50 mL/g/min; global MPR=2.11±0.53) compared to the control group (global MBF=2.92±0.52 mL/g/min; global MPR=3.28±0.57), while rest MBF showed no significant difference (global MBF=0.88±0.18 mL/g/min in the patient group vs. 0.92±0.13 mL/g/min in the control group).

Conclusion: This study demonstrates the feasibility of using a six-fold accelerated wideband perfusion pulse sequence, which provides diagnostically acceptable image quality during stress and is sensitive for detecting abnormal stress MBF and MPR in patients with ICDs.

Background: Cine cardiovascular magnetic resonance (CMR) faces the challenges of prolonged examination times and repeated breathhold (BH). This study evaluated the clinical feasibility of deep learning (DL)-accelerated cine sequences, which shorten the acquisition time (AT) while achieving comparable image quality (IQ) and function.

Methods: This prospective study included patients who underwent 3T CMR from August 2024 to March 2025. The examination included three cine sequences (2D segmented cine, 2D single-BH DL cine, and 2D free-breathing motion-corrected DL cine [FB-MOCO DL cine]). The actual total AT (including the time for short and long-axis scans, BH instructions, and resting time between BHs) was recorded. The overall IQ, blood pool to myocardium signal ratio (BMC), edge sharpness, three-dimensional volumetric mesh contour quality, biventricular cardiac function parameters, and left ventricular (LV) strain parameters were evaluated. The Friedman test was used to compare the above parameters among the three cine sequences. Correlation analysis and Bland-Altman analysis were used to evaluate the correlation and consistency between the two cine sequences.

Results: Eighty-six patients were evaluated (52.98±14.34 years, 79% 68/86 male). Compared with segmented cine (239.70 [224.55, 260.15])s, the total AT of single-BH DL cine (63.55 [60.98, 66.00])s and FB-MOCO DL cine (90.65 [79.43, 103.80])s decreased by 73% and 62%, respectively. There were no statistically significant differences in overall IQ and biventricular functional parameters among the three cine sequences. The three-dimensional volumetric mesh contour scores of the single-BH DL cine and FB-MOCO DL cine were higher than those of the segmented cine (P<0.001 and 0.04), but the edge sharpness and BMC were lower than those of the segmented cine. The LV strain of the two fast cine sequences was lower than that of the segmented cine.

Conclusion: Compared with traditional segmented cine, DL-accelerated cine enables ventricular imaging in a shorter acquisition time, with preserved IQ and quantitative cardiac function results.