Graham-Brown M P, Singh A S, Gulsin G S, Levelt E, Arnold J A, Stensel D J, Burton J O, McCann G P
John Walls Renal Unit, University Hospitals Leicester NHS Trust, Leicester, UK.
Department of Infection Immunity and Inflammation, School of Medicine and Biological Sciences, University of Leicester, Leicester, LE1 9HN, UK.
BMC Cardiovasc Disord. 2018 Jul 13;18(1):145. doi: 10.1186/s12872-018-0885-2.
Extent of myocardial fibrosis (MF) determined using late gadolinium enhanced (LGE) predicts outcomes, but gadolinium is contraindicated in advanced renal disease. We assessed the ability of native T1-mapping to identify and quantify MF in aortic stenosis patients (AS) as a model for use in haemodialysis patients.
We compared the ability to identify areas of replacement-MF using native T1-mapping to LGE in 25 AS patients at 3 T. We assessed agreement between extent of MF defined by LGE full-width-half-maximum (FWHM) and the LGE 3-standard-deviations (3SD) in AS patients and nine T1 thresholding-techniques, with thresholds set 2-to-9 standard-deviations above normal-range (1083 ± 33 ms). A further technique was tested that set an individual T1-threshold for each patient (T11SD). The technique that agreed most strongly with FWHM or 3SD in AS patients was used to compare extent of MF between AS (n = 25) and haemodialysis patients (n = 25).
Twenty-six areas of enhancement were identified on LGE images, with 25 corresponding areas of discretely increased native T1 signal identified on T1 maps. Global T1 was higher in haemodialysis than AS patients (1279 ms ± 5.8 vs 1143 ms ± 12.49, P < 0.01). No signal-threshold technique derived from standard-deviations above normal-range associated with FWHM or 3SD. T11SD correlated with FWHM in AS patients (r = 0.55) with moderate agreement (ICC = 0.64), (but not with 3SD). Extent of MF defined by T11SD was higher in haemodialysis vs AS patients (21.92% ± 1 vs 18.24% ± 1.4, P = 0.038), as was T1 in regions-of-interest defined as scar (1390 ± 8.7 vs 1276 ms ± 20.5, P < 0.01). There was no difference in the relative difference between remote myocardium and regions defined as scar, between groups (111.4 ms ± 7.6 vs 133.2 ms ± 17.5, P = 0.26).
Areas of MF are identifiable on native T1 maps, but absolute thresholds to define extent of MF could not be determined. Histological studies are needed to assess the ability of native-T1 signal-thresholding techniques to define extent of MF in haemodialysis patients. Data is taken from the PRIMID-AS (NCT01658345) and CYCLE-HD studies (ISRCTN11299707).
使用延迟钆增强（LGE）测定的心肌纤维化（MF）范围可预测预后，但钆在晚期肾病中为禁忌。我们评估了采用天然T1映射识别和量化主动脉瓣狭窄患者（AS）中MF的能力，将其作为用于血液透析患者的模型。
我们比较了25例3T场强的AS患者中，利用天然T1映射与LGE识别替代型MF区域的能力。我们评估了AS患者中，LGE半高宽（FWHM）和LGE 3标准差（3SD）所定义的MF范围与9种T1阈值技术之间的一致性，阈值设定为高于正常范围（1083±33ms）2至9个标准差。测试了另一种为每位患者设定个体T1阈值的技术（T11SD）。在AS患者中与FWHM或3SD一致性最强的技术用于比较AS患者（n = 25）和血液透析患者（n = 25）之间的MF范围。
LGE图像上识别出26个强化区域，T1图上识别出25个相应的天然T1信号离散增加区域。血液透析患者的整体T1高于AS患者（1279ms±5.8 vs 1143ms±12.49，P<0.01）。没有高于正常范围标准差衍生的信号阈值技术与FWHM或3SD相关。AS患者中T11SD与FWHM相关（r = 0.55），一致性中等（ICC = 0.64），（但与3SD不相关）。血液透析患者中由T11SD定义的MF范围高于AS患者（21.92%±1 vs 18.24%±1.4，P = 0.038），定义为瘢痕的感兴趣区域的T1也是如此（1390±8.7 vs 1276ms±20.5，P<0.01）。两组之间，远离心肌与定义为瘢痕的区域之间的相对差异无差异（111.4ms±7.6 vs 133.2ms±17.5，P = 0.26）。
MF区域可在天然T1图上识别，但无法确定定义MF范围的绝对阈值。需要进行组织学研究来评估天然T1信号阈值技术在血液透析患者中定义MF范围的能力。数据来自PRIMID - AS（NCT01658345）和CYCLE - HD研究（ISRCTN11299707）。
