Characterizing cardiac involvement in amyloidosis using cardiovascular magnetic resonance diffusion tensor imaging
Characterizing cardiac involvement in amyloidosis using cardiovascular magnetic resonance diffusion tensor imaging
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DOI：
10.1186/s12968-019-0563-2
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发表时间：
2019-09-05
影响因子：
6.4
通讯作者：
Kozerke, Sebastian
中科院分区：
文献类型：
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作者：
Gotschy, Alexander;von Deuster, Constantin;Kozerke, Sebastian
研究背景在体心血管磁共振（CMR）弥散张量成像（DTI）可以对病变心脏的心脏纤维结构改变进行成像。心脏淀粉样变性（CA）导致错误折叠蛋白质的心肌浸润，对心肌微观结构的影响未知。本研究应用CMR DTI在CA中评估与健康对照相比的微结构改变及其对心肌功能的影响。方法应用1.5T磁共振弥散加权二阶运动补偿自旋回波序列对10例CA患者（AL 8例，ATTR 2例）和10例健康对照者进行研究。此外，在所有受试者中获得左心室形态、射血分数、应变和天然T1值。在CA患者中，在给予钆后重复T1标测以计算细胞外容积分数（ECV）。CMR DTI分析得到标量扩散度量平均扩散率（MD）和各向异性分数（FA）以及肌纤维取向的特征，包括螺旋、横向和E2 A片角（HA、TA、E2 A）。结果CA患者和健康对照组的MD和FA存在显著差异（MD 1.77 ± 0.17 10（-3）vs 1.41 ± 0.07 10（-3）mm（2）/s，p < 0.001; FA 0.25 ± 0.04 vs 0.35 ± 0.03，p < 0.001）。CA人群中MD与天然T1表现出极好的相关性（r = 0.908，p < 0.001），而FA与ECV表现出显著的相关性（r =-0.851，p < 0.002）。HA在CA患者中表现出更多的肌纤维周向取向，以及更高的TA标准差和更高的绝对E2 A片角。发现透壁HA斜率与整体纵向应变强烈相关（r = 0.921，p < 0.001）。结论CA患者CMR DTI图像标量弥散参数较正常对照组有明显改变。MD升高和FA值降低表明CA中具有较高弥散的心肌紊乱，其与天然T1和ECV测量结果相关性良好。在CA患者中，CMR DTI显示肌纤维明显的周向取向，这可能为淀粉样变性患者中发生的全局纵向应变减少提供了依据。因此，CMR DTI捕捉淀粉样蛋白浸润的具体特征，这提供了对CA的微观结构后果的更深入的理解。
Background In-vivo cardiovascular magnetic resonance (CMR) diffusion tensor imaging (DTI) allows imaging of alterations of cardiac fiber architecture in diseased hearts. Cardiac amyloidosis (CA) causes myocardial infiltration of misfolded proteins with unknown consequences for myocardial microstructure. This study applied CMR DTI in CA to assess microstructural alterations and their consequences for myocardial function compared to healthy controls. Methods Ten patients with CA (8 AL, 2 ATTR) and ten healthy controls were studied using a diffusion-weighed second-order motion-compensated spin-echo sequence at 1.5 T. Additionally, left ventricular morphology, ejection fraction, strain and native T1 values were obtained in all subjects. In CA patients, T1 mapping was repeated after the administration of gadolinium for extracellular volume fraction (ECV) calculation. CMR DTI analysis was performed to yield the scalar diffusion metrics mean diffusivity (MD) and fractional anisotropy (FA) as well as the characteristics of myofiber orientation including helix, transverse and E2A sheet angle (HA, TA, E2A). Results MD and FA were found to be significantly different between CA patients and healthy controls (MD 1.77 +/- 0.17 10(- 3) vs 1.41 +/- 0.07 10(- 3) mm(2)/s, p < 0.001; FA 0.25 +/- 0.04 vs 0.35 +/- 0.03, p < 0.001). MD demonstrated an excellent correlation with native T1 (r = 0.908, p < 0.001) while FA showed a significant correlation with ECV in the CA population (r = - 0.851, p < 0.002). HA exhibited a more circumferential orientation of myofibers in CA patients, in conjunction with a higher TA standard deviation and a higher absolute E2A sheet angle. The transmural HA slope was found to be strongly correlated with the global longitudinal strain (r = 0.921, p < 0.001). Conclusion CMR DTI reveals significant alterations of scalar diffusion metrics in CA patients versus healthy controls. Elevated MD and lower FA values indicate myocardial disarray with higher diffusion in CA that correlates well with native T1 and ECV measures. In CA patients, CMR DTI showed pronounced circumferential orientation of the myofibers, which may provide the rationale for the reduction of global longitudinal strain that occurs in amyloidosis patients. Accordingly, CMR DTI captures specific features of amyloid infiltration, which provides a deeper understanding of the microstructural consequences of CA.