磁共振特征性追踪技术对肥厚型心肌病心肌应变的初步研究

目的采用心脏磁共振特征性追踪(cardiovascular magnetic resonance feature tracking,CMR-FT)技术对肥厚型心肌病患者的心功能及心肌节段应变进行分析,探讨CMR-FT对肥厚性心肌病患者早期运动异常检测的可行性。材料与方法对17例肥厚型心肌病患者及14名健康志愿者进行3.0 T SSFP电影序列扫描,使用CVI软件检测心功能,并对48个肥厚的心肌节段及健康志愿者中42个正常心肌节段进行特征性追踪(feature tracking,FT)后处理。结果肥厚型心肌病患者与健康志愿者左心功能参数(左心室舒张末期容积、左心室收缩末期容积及左心室射血分数)的差异无统计学意义(P均0.05),肥厚的心肌节段的圆周应变、长轴应变及峰值收缩期圆周应变、峰值收缩期长轴应变均低于正常的心肌节段[(-5.26±2.70)%vs(-11.68±2.06)%,(-7.92±5.07)%vs(-13.93±3.89)%,(-10.44±5.46)%vs(-18.43±2.99)%,(-12.29±8.17)%vs(-20.26±2.93)%,P均0.05]。结论对于心功能正常的肥厚性心肌病患者,CMR-FT技术能够早期检测出肥厚患者肥厚心肌节段应变的变化,提示心肌应变量的改变能够比左心室功能参数更早地发现心肌收缩功能异常。     

Biventricular myocardial strain analysis in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) using cardiovascular magnetic resonance feature tracking

Background

Fibrofatty degeneration of myocardium in ARVC is associated with wall motion abnormalities. The aim of this study was to examine whether Cardiovascular Magnetic Resonance (CMR) based strain analysis using feature tracking (FT) can serve as a quantifiable measure to confirm global and regional ventricular dysfunction in ARVC patients and support the early detection of ARVC.

Methods

We enrolled 20 patients with ARVC, 30 with borderline ARVC and 22 subjects with a positive family history but no clinical signs of a manifest ARVC. 10 healthy volunteers (HV) served as controls. 15 ARVC patients received genotyping for Plakophilin-2 mutation (PKP-2), of which 7 were found to be positive. Cine MR datasets of all subjects were assessed for myocardial strain using FT (TomTec Diogenes Software). Global strain and strain rate in radial, circumferential and longitudinal mode were assessed for the right and left ventricle. In addition strain analysis at a segmental level was performed for the right ventricular free wall.

Results

RV global longitudinal strain rates in ARVC (−0.68 ± 0.36 sec⁻¹) and borderline ARVC (−0.85 ± 0.36 sec⁻¹) were significantly reduced in comparison with HV (−1.38 ± 0.52 sec⁻¹, p ≤ 0.05). Furthermore, in ARVC patients RV global circumferential strain and strain rates at the basal level were significantly reduced compared with HV (strain: −5.1 ± 2.7 vs. -9.2 ± 3.6%; strain rate: −0.31 ± 0.13 sec⁻¹ vs. -0.61 ± 0.21 sec⁻¹). Even for patients with ARVC or borderline ARVC and normal RV ejection fraction (n=30) global longitudinal strain rate proved to be significantly reduced compared with HV (−0.9 ± 0.3 vs. -1.4 ± 0.5 sec⁻¹; p < 0.005). In ARVC patients with PKP-2 mutation there was a clear trend towards a more pronounced impairment in RV global longitudinal strain rate. On ROC analysis RV global longitudinal strain rate and circumferential strain rate at the basal level proved to be the best discriminators between ARVC patients and HV (AUC: 0.9 and 0.92, respectively).

Conclusion

CMR based strain analysis using FT is an objective and useful measure for quantification of wall motion abnormalities in ARVC. It allows differentiation between manifest or borderline ARVC and HV, even if ejection fraction is still normal.     

Global and regional left ventricular myocardial deformation measures by magnetic resonance feature tracking in healthy volunteers: comparison with tagging and relevance of gender

Background

Feature Tracking software offers measurements of myocardial strain, velocities and displacement from cine cardiovascular magnetic resonance (CMR) images. We used it to record deformation parameters in healthy adults and compared values to those obtained by tagging.

Methods

We used TomTec 2D Cardiac Performance Analysis software to derive global, regional and segmental myocardial deformation parameters in 145 healthy volunteers who had steady state free precession (SSFP) cine left ventricular short (basal, mid and apical levels) and long axis views (horizontal long axis, vertical long axis and left ventricular out flow tract) obtained on a 1.5 T Siemens Sonata scanner. 20 subjects also had tagged acquisitions and we compared global and regional deformation values obtained from these with those from Feature Tracking.

Results

For globally averaged measurements of strain, only those measured circumferentially in short axis slices showed reasonably good levels of agreement between FT and tagging (limits of agreement −0.06 to 0.04). Longitudinal strain showed wide limits of agreement (−0.16 to 0.03) with evidence of overestimation of strain by FT relative to tagging as the mean of both measures increased. Radial strain was systematically overestimated by FT relative to tagging with very wide limits of agreement extending to as much as 100% of the mean value (−0.01 to 0.23). Reproducibility showed similar relative trends with acceptable global inter-observer variability for circumferential measures (coefficient of variation 4.9%) but poor reproducibility in the radial direction (coefficient of variation 32.3%). Ranges for deformation parameters varied between basal, mid and apical LV levels with higher levels at base compared to apex, and between genders by both FT and tagging.

Conclusions

FT measurements of circumferential but not longitudinally or radially directed global strain showed reasonable agreement with tagging and acceptable inter-observer reproducibility. We record provisional ranges of FT deformation parameters at global, regional and segmental levels. They show evidence of variation with gender and myocardial region in the volunteers studied, but have yet to be compared with tagging measurements at the segmental level.     

房间隔应变率成像鉴别左室舒张功能假性正常表现

目的探讨房间隔应变率成像技术判定左室舒张功能假性正常的应用价值。方法30例正常人与左室舒张功能下降患者52例,脉冲多普勒测量二尖瓣口血流,组织多普勒测量二尖瓣环左室侧壁处速度,应变率成像观察房间隔应变率(SR)曲线、应变(S)曲线变化,SR曲线测量舒张早期峰值SRe,舒张晚期峰值SRa;S曲线测量舒张晚期峰值Sa,测量结果各组进行对照分析。结果左室舒张功能受损各组别SRe、Sa及SRe/SRa明显低于正常组(P<0.01)。结论房间隔应变率成像可鉴别左室舒张假性正常,并可定量评价左室舒张功能下降。     

应变及应变率成像技术评价左心房功能的研究进展

左心房功能在预测心血管事件发生中的重要性日益引起人们的关注, 应变及应变率成像技术为评价左心房功能提供了新方法。随着该技术的不断发展, 其在评价左心房功能的应用中越来越广泛和深入。本文对应变及应变率成像评价左心房功能方面的研究进展进行综述。     

Quantification of atrial dynamics using cardiovascular magnetic resonance: inter-study reproducibility

Background

Cardiovascular magnetic resonance (CMR) offers quantification of phasic atrial functions based on volumetric assessment and more recently, on CMR feature tracking (CMR-FT) quantitative strain and strain rate (SR) deformation imaging. Inter-study reproducibility is a key requirement for longitudinal studies but has not been defined for CMR-based quantification of left atrial (LA) and right atrial (RA) dynamics.

Methods

Long-axis 2- and 4-chamber cine images were acquired at 9:00 (Exam A), 9:30 (Exam B) and 14:00 (Exam C) in 16 healthy volunteers. LA and RA reservoir, conduit and contractile booster pump functions were quantified by volumetric indexes as derived from fractional volume changes and by strain and SR as derived from CMR-FT. Exam A and B were compared to assess the inter-study reproducibility. Morning and afternoon scans were compared to address possible diurnal variation of atrial function.

Results

Inter-study reproducibility was within acceptable limits for all LA and RA volumetric, strain and SR parameters. Inter-study reproducibility was better for volumetric indexes and strain than for SR parameters and better for LA than for RA dynamics. For the LA, reservoir function showed the best reproducibility (intraclass correlation coefficient (ICC) 0.94–0.97, coefficient of variation (CoV) 4.5–8.2 %), followed by conduit (ICC 0.78–0.97, CoV 8.2–18.5 %) and booster pump function (ICC 0.71–0.95, CoV 18.3–22.7). Similarly, for the RA, reproducibility was best for reservoir function (ICC 0.76–0.96, CoV 7.5–24.0 %) followed by conduit (ICC 0.67–0.91, CoV 13.9–35.9) and booster pump function (ICC 0.73–0.90, CoV 19.4–32.3). Atrial dynamics were not measurably affected by diurnal variation between morning and afternoon scans.

Conclusions

Inter-study reproducibility for CMR-based derivation of LA and RA functions is acceptable using either volumetric, strain or SR parameters with LA function showing higher reproducibility than RA function assessment. Amongst the different functional components, reservoir function is most reproducibly assessed by either technique followed by conduit and booster pump function, which needs to be considered in future longitudinal research studies.     

心脏MR特征追踪技术定量评估扩张型心肌病左心房心肌应变

目的 观察心脏MR特征追踪（CMR-FT）技术定量分析扩张性心肌病（DCM）左心房（LA）心肌应变的价值。方法 对28例临床诊断DCM患者（DCM组）及23名健康对照者（对照组）采集心脏MRI。采用CVI42后处理软件,以CMR-FT技术基于两腔心和四腔心图像获得LA应变参数,测量LA容积（LAV）参数;比较组间CMR参数的差异,分析DCM的LA应变参数与LA射血分数（LAEF）、氨基末端脑钠肽前体（NT-pro-BNP）的相关性。结果 相比对照组,DCM组LAV增大、LAEF减小,应变和应变率参数总应变（εs）、被动应变（εe）、主动应变（εa）、左心室收缩期峰值正向应变率（SRs）、左心室舒张早期LA峰值负向应变率（SRe）及左心室舒张晚期LA峰值负向应变率（SRa）绝对值均减小（P均<0.05）。DCM患者εs与LA总射血分数（LAEF_total）、εe与LA被动射血分数（LAEF_passive）及εa与LA主动射血分数（LAEF_active）均呈高度正相关（r=0.92、0.86、0.86,P均<0.05）,εs、εe、εa与NT-Pro-BNP均呈中度负相关（r=-0.49、-0.40、-0.44,P均<0.05）。结论 CMR-FT技术可评估DCM患者LA心肌应变,有助于定量分析其LA功能;DCM所致LA应变参数降低与容积参数及NT-pro-BNP相关。     

二维斑点追踪显像和应变率成像评价高血压病患者左心房功能的比较

S显著降低,LVR组左房mSRS、mSRE亦显著降低;②SRI技术:与对照组比较,LVR组左房mSRS、mSRE均显著降低;③STI与SRI技术获得的mSRS、mSRE、mSRA均具有高度相关性.结论 STI和SRI技术均可以准确评价左房功能,并且STI技术可以在高血压病患者左室重构发生前检测出左房壁形变能力降低,其敏感性高于SRI.     

MR特征追踪技术定量评估肥厚型心肌病心肌应变

目的 探讨MR特征追踪技术（CMR-FT）定量分析肥厚型心肌病（HCM）左心室整体和局部心肌应变的临床价值。方法 收集HCM患者60例（HCM组）及健康志愿者10名（对照组）。所有受检者均接受心脏MR检查,扫描序列包括心室短轴、二腔心、四腔心层面快速平衡稳态进动序列（FIESTA）和延迟增强扫描（LGE）。HCM组按有无强化分为无强化亚组和有强化亚组。采用CMR-FT后处理软件测定心肌整体的径向应变峰值（GPSR）、环向应变峰值（GPSC）、纵向应变峰值（GPSL）以及心室不同部位（心尖部、心室中部和基底部）的径向、环向和纵向应变峰值（PSR、PSC和PSL）。结果 有强化亚组、无强化亚组和对照组的GPSR、GPSC和GPSL差异有统计学意义（P均<0.05）,呈增高趋势。除心尖部PSL 3组间差异无统计学意义外,有强化亚组、无强化亚组和对照组的PSR、PSC和PSL差异均有统计学意义（P均<0.05）,在心脏各部位均呈上升趋势。LVEF、SV与GPSR、GPSC、GPSL均呈正相关（P均<0.05）。GPSR、GPSC、GPSL诊断HCM的ROC曲线下面积分别为0.79、0.82、0.77（P均<0.05）,其中GPSC的曲线下面积最大。结论 CMR-FT技术能够早期敏感地发现HCM的心肌应变功能障碍,且纵向应变受损早于或重于环向应变及径向应变。     

Clinical Utility of Cardiovascular Magnetic Resonance in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterized by substantial genetic and phenotypic heterogeneity, leading to considerable diversity in clinical course including the most common cause of sudden death in young people and a determinant of heart failure symptoms in patients of any age. Traditionally, two-dimensional echocardiography has been the most reliable method for establishing a clinical diagnosis of HCM. However, cardiovascular magnetic resonance (CMR), with its high spatial resolution and tomographic imaging capability, has emerged as a technique particularly well suited to characterize the diverse phenotypic expression of this complex disease. For example, CMR is often superior to echocardiography for HCM diagnosis, by identifying areas of segmental hypertrophy (ie., anterolateral wall or apex) not reliably visualized by echocardiography (or underestimated in terms of extent). High-risk HCM patient subgroups identified with CMR include those with thin-walled scarred LV apical aneurysms (which prior to CMR imaging in HCM remained largely undetected), end-stage systolic dysfunction, and massive LV hypertrophy. CMR observations also suggest that the cardiomyopathic process in HCM is more diffuse than previously regarded, extending beyond the LV myocardium to include thickening of the right ventricular wall as well as substantial morphologic diversity with regard to papillary muscles and mitral valve. These findings have implications for management strategies in patients undergoing invasive septal reduction therapy. Among HCM family members, CMR has identified unique phenotypic markers of affected genetic status in the absence of LV hypertrophy including: myocardial crypts, elongated mitral valve leaflets and late gadolinium enhancement. The unique capability of contrast-enhanced CMR with late gadolinium enhancement to identify myocardial fibrosis has raised the expectation that this may represent a novel marker, which may enhance risk stratification. At this time, late gadolinium enhancement appears to be an important determinant of adverse LV remodeling associated with systolic dysfunction. However, the predictive significance of LGE for sudden death is incompletely resolved and ultimately future large prospective studies may provide greater insights into this issue. These observations underscore an important role for CMR in the contemporary assessment of patients with HCM, providing important information impacting diagnosis and clinical management strategies.     

心房颤动状态下左心耳功能的超声应变率研究

目的应用应变率显像（SRI）分析持续性心房颤动（房颤）患者左心耳功能变化特点，探讨病理状态下左心耳机械运动的变化。方法分别选择29例持续性房颤患者和31例对照者，经食管超声心动图（TEE）获取左心耳超声图像，应用SRI技术对两组左心耳壁各节段应变率（SR）相关指标变化特点进行分析和比较。结果对照组中，左心耳壁顶部收缩期峰值应变率（SR）s和舒张期应变率（SRD）均高于其余节段（P〈O．01）。持续房颤组中，心耳顶部SRs仅高于间隔壁及侧壁中段（P〈0．05），心耳顶部SRD，仅高于间隔壁中段（P〈0．05）。持续房颤组各节段SRs和SRD较对照组均降低（P〈0．01）。对照组中，心耳顶部SRs与左心耳面积变化率和左心耳充盈速度呈正相关（r=0．724，0．637，P〈0．001）。结论左心耳顶部SRs决定了心耳整体的排空能力，房颤患者心耳壁的舒缩功能明显降低且失去有效协调运动。     

基于心脏磁共振特征追踪技术的高血压患者早期左房功能障碍的定量研究

目的采用心脏磁共振特征追踪技术定量评估高血压患者早期左房功能障碍。材料与方法连续性收集2012年1月至2013年12月在我院确诊为高血压并接受心脏磁共振检查的患者30例。所有患者均除外左房扩大、左室射血分数<50%及其他心血管疾病,并纳入同时期30名年龄及性别匹配的正常人作为对照组。采用心脏磁共振特征追踪技术,同时在心脏两腔心及四腔心电影序列上进行左房纵向应变分析,分别获得左房存储期、导管期及泵血期的射血分数、应变力及应变率,比较两组的临床及心脏磁共振参数。结果两组的平均年龄均为(45.93±10.38)岁,男性占66.6%(20/30)。高血压组的体表面积、体重指数及静息状态下收缩压和舒张压均显著高于对照组。同时,高血压患者左室射血分数[(64.08±7.99)%vs(59.89±4.59)%,P=0.018]及左室心肌质量[(61.14±10.59)g/m^2 vs(37.93±10.45)g/m^2,P<0.001]亦显著增大。左房最大容积、收缩期前容积及最小容积指数两组间均无显著差异。高血压组左房存储期及导管期的射血分数及应变力较对照组均明显减小,而左房泵血期各参数两组间差异均无统计学意义。结论心脏磁共振特征追踪技术有潜力在左房增大之前定量检测高血压患者的左房功能障碍,主要表现为左房存储期及导管期功能下降而泵血期功能保留。     

应变率成像评价陈旧性心肌梗死患者左心房收缩功能

目的 探讨应变率成像评价陈旧性心肌梗死患者左心房收缩功能的价值.方法 对30例陈旧性心肌梗死患者(心梗组)和25例正常人(对照组),应用应变率成像测量左心房侧壁及房间隔心肌运动速度;分析心梗组与对照组心房侧壁及房间隔收缩功能的改变.结果 ①与对照组相比,心梗组左心房心肌运动速度在心室收缩期和心室舒张早期减低,而在心室舒张晚期增高,差异有统计学意义(P<0.05).②与对照组相比,心梗组左房被动射血量指数减少,主动射血量指数增加,差异有统计学意义(P<0.001).结论 应变率成像可以准确评价陈旧性心肌梗死患者左房功能.     

三维斑点追踪技术评价正常人左房心肌应变的初步研究

目的 探讨三维斑点追踪显像(3D-STI)技术评价正常成年人左房心肌应变的临床价值.方法 对健康成年志愿者60例采集全容积左室心尖四腔和两腔观图像并存储,运用3D-STI分析软件进行脱机分析,软件自动将左房心肌分为16节段,分别为前壁、前间隔、后间隔、下壁、后侧壁、前侧壁的基底段及中间段,以及前壁、间隔、侧壁、下壁的房顶段.比较左心房16个心肌节段之间纵向峰值应变(PALS)、纵向应变达峰时间(TPLS)、圆周峰值应变(PACS)、圆周应变达峰时间(TPCS)、面积峰值应变(PAAS)、面积应变达峰时间(TPAS)的差异.结果 ①基底段各壁PALS较房顶段各壁高,基底段前侧壁及后侧壁PALS较中间段高,中间段后间隔、下壁及后侧壁PALS高于房顶段间隔、下壁及侧壁;房顶段各壁的PACS及PAAS高于中间段及基底段各壁,后间隔基底段PACS低于中间段,以上差异均有统计学意义(P ＜0.05).②同一水平的各房壁间PALS、PACS、PAAS差异无统计学意义.③间隔TPLS、TPCS、TPAS小于侧壁,前壁TPLS、下壁TPCS及TPAS小于侧壁,差异均有统计学意义(P＜0.05).结论 3D-STI可反映正常人左房心肌应变规律,为评估不同病理状态下左房功能改变的位置和程度提供重要参考.     

应用斑点追踪成像技术评价肥厚型心肌病患者的左室节段径向应变及圆周应变

目的应用斑点追踪成像技术评价肥厚型心肌病（HCM）患者左室径向应变和圆周应变的变化规律。方法HCM组18例,健康对照组36例,超声心动图获取其短轴二尖瓣水平、乳头肌水平及心尖水平切面,运用斑点追踪技术分析不同水平不同节段的径向应变及圆周应变。结果HCM组各节段径向应变减低,多数节段圆周应变减低,且以径向应变降低更明显,差异均有统计学意义（P〈0．05）。与对照组比较,HCM组增厚节段与未增厚节段的径向应变和圆周应变降低,但差异无统计学意义（P〉0．05）。结论斑点追踪技术能较好地评价HCM的局部收缩功能。     

应变/应变率技术评价超重及肥胖患者左心房功能的研究

目的 应用应变/应变率技术评价超重及肥胖者左心房功能的变化.方法 30例超重者(28kg/m2 ＞BMI≥24 kg/m2),30例肥胖者(BMI≥28 kg/m2)及30例正常人.应用超声心动图及应变/应变率技术测量左心房5个壁10个节段左房应变(S)、左室收缩期左房应变率峰值(SSR)、左室舒张早期左房应变率峰值(ESR)及左室舒张晚期左房应变率峰值(ASR),并计算出平均值进行比较.结果 与正常组相比,超重组平均SSR及平均ESR减低,肥胖组平均S、平均SSR及平均ESR降低,超重组平均ASR降低;肥胖组平均ESR较超重组降低.结论 超重者左房储存器、管道及助力泵功能均受损,肥胖者左房储存器及管道功能受损更为明显,而助力泵功能未见明显受损.左房的三个功能相互调节来维持左室充盈.应变及应变率技术可用来评价超重及肥胖者左房功能改变.     

Coronary microvascular ischemia in hypertrophic cardiomyopathy - a pixel-wise quantitative cardiovascular magnetic resonance perfusion study

Background

Microvascular dysfunction in HCM has been associated with adverse clinical outcomes. Advances in quantitative cardiovascular magnetic resonance (CMR) perfusion imaging now allow myocardial blood flow to be quantified at the pixel level. We applied these techniques to investigate the spectrum of microvascular dysfunction in hypertrophic cardiomyopathy (HCM) and to explore its relationship with fibrosis and wall thickness.

Methods

CMR perfusion imaging was undertaken during adenosine-induced hyperemia and again at rest in 35 patients together with late gadolinium enhancement (LGE) imaging. Myocardial blood flow (MBF) was quantified on a pixel-by-pixel basis from CMR perfusion images using a Fermi-constrained deconvolution algorithm. Regions-of-interest (ROI) in hypoperfused and hyperemic myocardium were identified from the MBF pixel maps. The myocardium was also divided into 16 AHA segments.

Results

Resting MBF was significantly higher in the endocardium than in the epicardium (mean ± SD: 1.25 ± 0.35 ml/g/min versus 1.20 ± 0.35 ml/g/min, P < 0.001), a pattern that reversed with stress (2.00 ± 0.76 ml/g/min versus 2.36 ± 0.83 ml/g/min, P < 0.001). ROI analysis revealed 11 (31%) patients with stress MBF lower than resting values (1.05 ± 0.39 ml/g/min versus 1.22 ± 0.36 ml/g/min, P = 0.021). There was a significant negative association between hyperemic MBF and wall thickness (β = −0.047 ml/g/min per mm, 95% CI: −0.057 to −0.038, P < 0.001) and a significantly lower probability of fibrosis in a segment with increasing hyperemic MBF (odds ratio per ml/g/min: 0.086, 95% CI: 0.078 to 0.095, P = 0.003).

Conclusions

Pixel-wise quantitative CMR perfusion imaging identifies a subgroup of patients with HCM that have localised severe microvascular dysfunction which may give rise to myocardial ischemia.     

In vivo cardiovascular magnetic resonance diffusion tensor imaging shows evidence of abnormal myocardial laminar orientations and mobility in hypertrophic cardiomyopathy

Background

Cardiac diffusion tensor imaging (cDTI) measures the magnitudes and directions of intramyocardial water diffusion. Assuming the cross-myocyte components to be constrained by the laminar microstructures of myocardium, we hypothesized that cDTI at two cardiac phases might identify any abnormalities of laminar orientation and mobility in hypertrophic cardiomyopathy (HCM).

Methods

We performed cDTI in vivo at 3 Tesla at end-systole and late diastole in 11 healthy controls and 11 patients with HCM, as well as late gadolinium enhancement (LGE) for detection of regional fibrosis.

Results

Voxel-wise analysis of diffusion tensors relative to left ventricular coordinates showed expected transmural changes of myocardial helix-angle, with no significant differences between phases or between HCM and control groups. In controls, the angle of the second eigenvector of diffusion (E2A) relative to the local wall tangent plane was larger in systole than diastole, in accord with previously reported changes of laminar orientation. HCM hearts showed higher than normal global E2A in systole (63.9° vs 56.4° controls, p = 0.026) and markedly raised E2A in diastole (46.8° vs 24.0° controls, p < 0.001). In hypertrophic regions, E2A retained a high, systole-like angulation even in diastole, independent of LGE, while regions of normal wall thickness did not (LGE present 57.8°, p = 0.0028, LGE absent 54.8°, p = 0.0022 vs normal thickness 38.1°).

Conclusions

In healthy controls, the angles of cross-myocyte components of diffusion were consistent with previously reported transmural orientations of laminar microstructures and their changes with contraction. In HCM, especially in hypertrophic regions, they were consistent with hypercontraction in systole and failure of relaxation in diastole. Further investigation of this finding is required as previously postulated effects of strain might be a confounding factor.

Electronic supplementary material

The online version of this article (doi:10.1186/s12968-014-0087-8) contains supplementary material, which is available to authorized users.     

肥厚型心肌病患者左心房功能的应变率评价

目的 探讨应变率成像技术评价肥厚型心肌病(HCM)患者左心房功能的价值.方法 根据左室流出道压差将36例HCM患者分为两组:非梗阻性HCM组[左室流出道压差<20 mmHg(1 mm Hg=0.133 kPa)]和梗阻性HCM组(左室流出道压差≥20mmHg).分别采集各受试者的心尖二腔、心尖四腔和心尖左室长轴观TVI图像,测量心室收缩期左心房峰值应变率(LASRs)、心室舒张早期左心房峰值应变率(LASRe)、心房收缩期左心房峰值应变率(LASRa)和心室舒张早期空间隔峰值应变率(LVSRe),计算其平均值(mLASRs、mLASRe、mLASRa和mLVSRe).结果 与对照组比较,非梗阻性HCM组和梗阻性HCM组mLASRs、mLASRe和mLVSRe减低,mLASRa增高,差异均有统计学意义(P<0.05).与非梗阻性HCM组比较,梗阻性HCM组mLASRe和mLVSRe减低,mLASRa增高,差异均有统计学意义(P<0.05).梗阻性HCM组与非梗阻性HCM组的mLASRa和mLVSRc均呈现著负相关(r=-0.67,-0.75;P<0.01,0.01).结论 HCM患者左心房功能发生改变,表现为储蓄功能和管道功能减低,辅泵功能增加.应变率成像技术能够评价左心房功能,为临床提供有价值的信息.