Journal of Cardiovascular Magnetic Resonance最新文献

Background: Impaired global coronary flow reserve (G-CFR), evaluated through phase-contrast cine cardiovascular magnetic resonance (PC-CMR), has been linked to worse outcomes in patients with cardiovascular disease. This study aimed to investigate the prognostic value of G-CFR improvement, as evaluated using PC-CMR imaging pre- and post-percutaneous coronary intervention (PCI).

Methods: In this single-center study, 320 patients with chronic coronary syndrome (CCS) who underwent pre- and post-PCI PC-CMR measurements were followed-up to determine major adverse cardiac or cerebrovascular events (MACCE) predictors. MACCE was defined as a composite of cardiac death, nonfatal myocardial infarction, hospitalization due to heart failure, or ischemic stroke. The association between CMR parameters, including baseline data, G-CFR changes post-PCI and MACCE was investigated.

Results: G-CFR improvement was observed in 165 (51.6%) patients, while MACCE occurred in 26 (8.1%) during a median follow-up period of 2.5 years. G-CFR improvement was significantly associated with a lower pre-PCI G-CFR. The log-rank test revealed a significant association between patients without G-CFR improvement post-PCI and a poor prognosis. Patients with lower pre-PCI G-CFR and lack of G-CFR improvement exhibited the highest incidence of MACCE. The multivariable Cox proportional hazard model revealed that lack of G-CFR improvement was an independently significant MACCE predictor from pre-PCI G-CFR and SYNTAX score.

Conclusions: Besides the association between pre- and post-PCI lower G-CFR and worse prognosis, the presence or absence of G-CFR improvement post-PCI may provide novel insights into the prognosis following elective PCI in patients with CCS.

Background: Fabry disease (FD) is an X-linked inherited lysosomal storage disease that is caused by deficient activity of the enzyme alpha-galactosidase A. Cardiovascular magnetic resonance (CMR) imaging can detect cardiac sphingolipid accumulation using native T1 mapping. The kidneys are often visible in cardiac CMR native T1 maps, however it is currently unknown if the maps can be used to detect sphingolipid accumulation in the kidneys of FD patients. Therefore, the aim of this study was to evaluate if cardiac dedicated native T1 maps can be used to detect sphingolipid accumulation in the kidneys.

Methods: FD patients (n=18, 41 ± 10 years, 44% male) and healthy subjects (n=38, 41 ± 16 years, 47% male) were retrospectively enrolled. Native T1 maps were acquired at 1.5T (MAGNETOM Aera) using MOLLI research sequences. Native T1 values were measured by manually delineating regions of interest (ROI) in the renal cortex, renal medulla, heart, spleen, blood, and liver. Endo- and epicardial borders were delineated in the myocardium and averaged across all slices. Blood ROIs were placed in the left-ventricular blood pool in the midventricular slice.

Results: There were no differences in native T1 between the FD patients and the healthy subjects in the renal cortex (1034±88 ms vs 1056±59 ms, p=0.29), blood (1614±111 ms vs 1576 ± 100 ms, p=0.22), spleen (1143±45 ms vs 1132±70 ms, p=0.54) or liver (568±49 ms vs 557±47 ms, p=0.41). Native T1 was lower in the hearts of the FD patients compared to healthy subjects (951±79 vs 1006±38, p<0.01), and higher in the renal medulla (1635±144 vs 1514±81, p<0.01). The results were similar when stratified for sex.

Conclusion: Compared to healthy subjects, patients with FD and cardiac involvement had no differences in native T1 of the renal cortex. FD patients had higher native T1 in the renal medulla, which is not totally explained by differences in blood native T1 but may reflect a hyperfiltration state in the development of renal failure. The findings suggest that sphingolipid accumulation in the renal cortex in FD patients could not be detected with cardiac dedicated research native T1 maps.

Background: Right ventricular (RV) dyssynchrony or post systolic contraction (PSC) cause inefficient pumping and have not been investigated as prognostic markers in pulmonary arterial hypertension (PAH).

Objectives: To investigate if RV dyssynchrony and PSC are prognostic markers of transplantation-free survival in PAH and if multiple RV views improve the prognostication.

Methods: Patients with PAH undergoing cardiac magnetic resonance (CMR) between 2003-2021 were included. For strain analysis, endocardial end-diastolic RV contours were delineated in RV 3-chamber (RV3ch), 4-chamber (4ch) and midventricular short axis slice (SAX). RV dyssynchrony was defined as standard deviation of time to peak strain in the walls from one (4ch), two (4ch and SAX) or three views (4ch, SAX and RV3ch). PSC was defined as peak strain occurring after pulmonary valve closure. Outcome was defined as death or lung transplantation.

Results: One hundred-one patients (58±19 years, 66% women) were included. Median follow-up was 37 [51] months. There were 60 events (55 deaths and 5 lung transplantations). Outcome was associated with RV dyssynchrony from three views and with RV strain in 4ch. An increase of RV dyssynchrony - from 3 views - by 1% was associated with a 10% increased risk of lung transplantation or death. There was no association between outcome and RV dyssynchrony in one or two views nor with PSC.

Conclusion: Right ventricular dyssynchrony from three views were associated with outcome in PAH, whereas assessing dyssynchrony from one or two views and PSC were not. This implies that assessment of multiple instead of single RV views potentially could be used for prognostication in PAH.

Background: Aortic dilation is seen in pediatric/young adult patients with bicuspid aortic valve (BAV), and hemodynamic markers to predict aortic dilation are necessary for monitoring. Although promising hemodynamic metrics, such as abnormal wall shear stress (WSS) magnitude, have been proposed for adult BAV patients using 4D flow cardiovascular magnetic resonance, those for pediatric BAV patients have less frequently been reported, partly due to scarcity of data to define normal WSS range. To circumvent this challenge, this study aims to investigate if a recently proposed 4D flow-based hemodynamic measurement, abnormal flow directionality, is associated with aortic dilation in pediatric/young adult BAV patients.

Methods: 4D flow scans for BAV patients (<20 years old) and age-matched controls were retrospectively enrolled. Static segmentation for the aorta and pulmonary arteries was obtained to quantify peak systolic hemodynamics and diameters in the proximal aorta. In addition to peak velocity, wall shear stress (WSS), vorticity, helicity, and viscous energy loss, direction of aortic velocity and WSS in BAV patients was compared with that of control atlas using registration technique; angle differences of >60deg and >120deg were defined as moderately and severely abnormal, respectively. Association between the obtained metrics and normalized diameters (Z-scores) were evaluated at the sinotubular junction, mid ascending aorta, and distal ascending aorta.

Results: Fifty-three BAV patients, including eighteen with history of repaired aortic coarctation, and seventeen controls were enrolled. Correlation between moderately abnormal velocity/WSS direction and aortic Z-scores was moderate to strong at the sinotubular junction and mid ascending aorta (R=0.62-0.81; p<0.001) while conventional measurements exhibited weaker correlation (|R|=0.003-0.47, p=0.009-0.99) in all subdomains. Multivariable regression analysis found moderately abnormal velocity direction and existence of aortic regurgitation (only for isolated BAV group) were independently associated with mid ascending aortic Z-scores.

Conclusion: Abnormal velocity and WSS directionality in the proximal aorta was strongly associated with aortic Z-scores in pediatric/young adult BAV patients.

Background: The diagnosis of myocarditis by CMR requires the use of T2 and T1 weighted imaging, ideally incorporating parametric mapping. Current 2D mapping sequences are acquired sequentially and involve multiple breath-holds resulting in prolonged scan times and anisotropic image resolution. We developed an isotropic free-breathing 3D whole-heart sequence which allows simultaneous T1 and T2 mapping and validated it in patients with suspected acute myocarditis.

Methods: Eighteen healthy volunteers and 28 patients with suspected myocarditis underwent conventional 2D T1 and T2 mapping with whole heart coverage and 3D joint T1/T2 mapping on a 1.5T scanner. Acquisition time, image quality, and diagnostic performance were compared. Qualitative analysis was performed using a 4-point Likert scale. Bland-Altman plots were used to assess the quantitative agreement between 2D and 3D sequences.

Results: The 3D T1/T2 sequence was acquired in 8mins 26s under free breathing, whereas 2D T1 and T2 sequences were acquired with breath holds in 11mins 44s (p=0.0001). All 2D images were diagnostic. For 3D images, 89% of T1 and 96% of T2 images were diagnostic with no significant difference in the proportion of diagnostic images for the 3D and 2D T1 (p=0.2482) and T2 maps (p=1.0000). Systematic bias in T1 was noted with biases of 102ms, 115ms, and 152ms for basal-apical segments, with a larger bias for higher T1 values. Good agreement between T2 values for 3D and 2D techniques was found (bias of 1.8ms, 3.9ms, and 3.6ms for basal-apical segments). The sensitivity and specificity of the 3D sequence for diagnosing acute myocarditis was 74% (95% confidence interval [CI] 49-91%) and 83% (36-100%) respectively, with an estimated c-statistic (95% CI) of 0.85 (0.79-0.91) and no statistically significant difference between the 2D and 3D sequences for the detection of acute myocarditis for T1 (p=0.2207) or T2 (p=1.0000).

Conclusion: Free-breathing whole heart 3D joint T1/T2 mapping was comparable to 2D mapping sequences with respect to diagnostic performance, but with the added advantages of free-breathing, and shorter scan times. Further work is required to address the bias noted at high T1 values, but this did not significantly impact on diagnostic accuracy.

Background: Cardiovascular magnetic resonance (CMR) is an emerging imaging modality for assessing anatomy and function of the fetal heart in congenital heart disease (CHD). This study aimed to evaluate myocardial strain using fetal CMR feature tracking (FT) in different subtypes of CHD.

Methods: Fetal CMR FT analysis was retrospectively performed on four-chamber cine images acquired with Doppler US gating at 3 Tesla. Left ventricular (LV) global longitudinal strain (GLS), LV global radial strain (GRS), LV global longitudinal systolic strain rate (SR), and right ventricular (RV) GLS were quantified using a dedicated software optimized for fetal strain analysis. Analysis was performed in normal fetuses and different CHD subtypes (d-Transposition of the great arteries (dTGA), hypoplastic left heart syndrome (HLHS), coarctation of the aorta (CoA), tetralogy of Fallot (TOF), RV-dominant atrioventricular septal defect (AVSD), and critical pulmonary stenosis or atresia (PS/PA)). Analyses of variance (ANOVA) with Tukey post-hoc test was used for group comparisons.

Results: A total of 60 fetuses were analyzed (8/60 (13%) without CHD, 52/60 (87%) with CHD). Myocardial strain was successfully assessed in 113/120 ventricles (94%). Compared to controls, LV GLS was significantly reduced in fetuses with HLHS (-18.6±2.7% vs. -6.2±5.6%; p<0.001) and RV-dominant AVSD (-18.6±2.7% vs. -7.7±5.0%; p=0.003) and higher in fetuses with CoA (-18.6±2.7% vs. -25.0±4.3%; p=0.038). LV GRS was significantly reduced in fetuses with HLHS (25.7±7.5% vs. 11.4±9.7%; p=0.024). Compared to controls, RV GRS was significantly reduced in fetuses with PS/PA (-16.1±2.8% vs. -8.3±4.2%; p=0.007). Across all strain parameters, no significant differences were present between controls and fetuses diagnosed with dTGA and TOF.

Conclusions: Fetal myocardial strain assessment with CMR FT in CHD is feasible. Distinct differences are present between various types of CHD, suggesting potential implications for clinical decision-making and prognostication in fetal CHD.

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

Methods: In this work, we developed a 2D 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 0^th and 1^st gradient moments at both the TE and TR, except for the flow-encoded acquisition, for which the 1^st gradient moment at the TE is determined by the VENC. Our proposed sequence was tested in both phantoms and in healthy volunteers (n=11), to measure aortic flow. In volunteers, both a breath-hold and a free-breathing 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 breath-hold (bh) and free-breathing (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.