通过心血管磁共振成像对压力负荷过重的左、右心疾病进行天然T1和T2 mapping
Native T1 and T2 mapping by cardiovascular magnetic resonance imaging in pressure overloaded left and right heart diseases.
作者信息
Wang Jing, Zhao Hang, Wang Yue, Herrmann Howard C, Witschey Walter R T, Han Yuchi
机构信息
Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Department of Cardiology, PLA General Hospital, Beijing 100853, China.
出版信息
J Thorac Dis. 2018 May;10(5):2968-2975. doi: 10.21037/jtd.2018.04.141.
BACKGROUND
Pulmonary arterial hypertension (PAH) and severe aortic valve stenosis (AS) are diseases characterized by increased afterload of the right and left heart, respectively. Our study aims to investigate the differences of myocardial tissue characteristics in the pressure overloaded left and right hearts, especially in the shared interventricular septum, as detected by native T1 and T2 relaxation times.
METHODS
Eighteen patients with PAH and 19 patients with severe AS in addition to 5 healthy volunteers underwent 1.5-T CMR examination with native T1 and T2 mapping. Mean T1 and T2 value were measured at the right ventricular (RV) free wall, superior RV insertion, inferior RV insertion, interventricular septum and left ventricular (LV) lateral wall.
RESULTS
Compared with controls and AS group, T1 was significantly elevated in the RV insertion in PAH group (P=0.015), while no statistically significant differences were seen in other segments among the three groups. There was an increase of T2 in the RV insertion in AS and PAH groups (P=0.01). Significant T2 elevation was also observed in the RV free wall of PAH group, and the LV lateral wall of AS group compared with the control group. RV insertion T2 was significantly correlated with RV end-diastolic volume index (r=0.608, P=0.016) and RV mass index (r=0.57, P=0.026) in the PAH group. LV lateral wall T2 and RV insertion T2 were significantly correlated with aortic valve mean gradients in the AS group (r=0.56, P=0.02; r=0.58, P=0.01, respectively).
CONCLUSIONS
In pressure overload diseases, both T1 and T2 values increase in the myocardium. The alterations seen in the RV insertion sites in the septum was more pronounced with RV pressure overload. T2 values also correlated with structural and functional remodeling in both diseases. Combining T1 and T2 mapping may help to better characterize the alternation of myocardial composition in pressure overloaded heart diseases.
背景
肺动脉高压（PAH）和重度主动脉瓣狭窄（AS）分别是以右心和左心后负荷增加为特征的疾病。我们的研究旨在通过检测固有T1和T2弛豫时间，研究压力超负荷的左心和右心中心肌组织特征的差异，特别是在共同的室间隔中。
方法
18例PAH患者、19例重度AS患者以及5名健康志愿者接受了1.5-T心脏磁共振成像（CMR）检查，并进行固有T1和T2成像。测量右心室（RV）游离壁、RV上插入点、RV下插入点、室间隔和左心室（LV）侧壁的平均T1和T2值。
结果
与对照组和AS组相比，PAH组RV插入点处的T1显著升高（P=0.015），而三组其他节段未见统计学显著差异。AS组和PAH组RV插入点处的T2升高（P=0.01）。与对照组相比，PAH组RV游离壁和AS组LV侧壁的T2也显著升高。在PAH组中，RV插入点处的T2与RV舒张末期容积指数显著相关（r=0.608, P=0.016）和RV质量指数（r=0.57, P=0.026）。在AS组中，LV侧壁T2和RV插入点处的T2与主动脉瓣平均梯度显著相关（分别为r=0.56, P=0.02；r=0.58, P=0.01）。
结论
在压力超负荷疾病中，心肌中的T1和T2值均升高。室间隔中RV插入点处的改变在RV压力超负荷时更为明显。在这两种疾病中，T2值也与结构和功能重塑相关。结合T1和T2成像可能有助于更好地表征压力超负荷心脏病中心肌成分的改变。
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