Assessment of Diffuse Myocardial Fibrosis by Using MR Imaging in Asymptomatic Patients with Aortic Stenosis

作者：Lee Seung Pyo; Lee Whal^*; Lee Joo Myung; Park Eun Ah; Kim Hyung Kwan; Kim Yong Jin; Kim Yong Jin; Sohn Dae Won

来源：Radiology, 2015, 274(2): 359-369.

DOI：10.1148/radiol.14141120

Purpose: To assess whether native T1 mapping provides noninvasive estimation of diffuse myocardial fibrosis and whether it correlates with subclinical myocardial dysfunction in asymptomatic patients with aortic stenosis ( AS). Materials and Methods: The local institutional review board approved the study, and all patients gave informed consent. Eighty asymptomatic patients with moderate or severe AS and normal left ventricular ( LV) ejection fraction ( mean age, 67 years; range, 31- 81 years) and 15 sex- matched control subjects ( mean age, 33 years; range, 23- 41 years) were prospectively enrolled. Patients underwent two- dimensional echocardiography, speckle tracking imaging, and cardiac 3.0-T magnetic resonance ( MR) imaging, including mapping of T1 relaxation time by using the modified Look- Locker inversion- recovery sequence. Correlations between native T1 values and the degree of diffuse fibrosis in myocardial specimens obtained during aortic valve replacement surgery were analyzed in a subset of 20 patients. Correlations between parameters of myocardial function and structure and native T1 values were assessed with Pearson correlation coefficients. Results: Native T1 values correlated well with the degree of diffuse myocardial fibrosis in intraoperative myocardial biopsy specimens ( r = 0.777, P < .001) and differed significantly between patients with AS and control subjects ( 1208 msec 6 45 vs 1169 msec 6 21, P,.001). LV volumes and mass differed significantly according to AS groups, categorized by T1 tertiles ( all P,.001), as well as degree of AS severity ( 0.55 cm2/ m2 6 0.14 for lowest native T1 tertile, 0.46 cm2/ m2 6 0.12 for middle native T1 tertile, and 0.45 cm2/ m2 6 0.13 for highest native T1 tertile [ P =.008] for indexed aortic valve area at echocardiography). Native T1 correlated significantly with global longitudinal strain measured with two- dimensional speckle tracking imaging ( r = 0.598, P,.001), e9 velocity ( r = 20.437, P,.001), and indexed left atrial volume ( r = 0.475, P,.001). Conclusion: Native T1 mapping provides a noninvasive estimation of diffuse myocardial fibrosis and correlates with subclinical myocardial dysfunction in asymptomatic patients with AS.

• 出版日期2015-2