Characterization of myocardial T1-mapping bias caused by intramyocardial fat in inversion recovery and saturation recovery techniques.
Characterization of myocardial T1-mapping bias caused by intramyocardial fat in inversion recovery and saturation recovery techniques.
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DOI：
10.1186/s12968-015-0136-y
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发表时间：
2015-05-10
期刊：
影响因子：
--
通讯作者：
Arai AE
中科院分区：
文献类型：
--
作者：
Kellman P;Bandettini WP;Mancini C;Hammer-Hansen S;Hansen MS;Arai AE
心肌中T1的定量测量可用于检测局灶性和弥漫性疾病过程，如间质纤维化或水肿。当心肌中的体素也包含脂肪时，存在部分体积问题。在替代性纤维化的脂肪瘤样化生的情况下，部分体积与脂肪发生在组织边界或心肌内，这在慢性心肌梗死中常见。脂肪的存在导致T1测量的偏倚。本文描述了广泛使用的T1标测方案使用平衡稳态自由进动读出的这种伪影的机制以及对非共振频率的依赖。进行模拟以说明具有不同脂肪分数的心肌和脂肪的双指数混合物的单指数拟合的行为。反转恢复和饱和恢复成像协议使用平衡的稳态自由进动被认为是。对慢性心肌梗死受试者进行T1标测、水/脂肪分离成像和晚期增强成像。在n = 17例慢性心肌梗死受试者中，8例患者（47%）的脂肪瘤性化生明显。低至5%的脂肪分数导致异相条件下T1升高约6%，同相条件下T1降低约5%。在脂肪比例为38%的脂肪瘤性化生中观察到超过1000 ms的T1偏倚，这与特定成像方案的模拟非常一致。当心肌中存在水和脂肪的混合物时，通过广泛使用的平衡稳态自由进动标测方法测量心肌T1会受到偏倚。心肌内脂肪经常存在于心肌瘢痕组织中，这是由于脂肪瘤性化生，一种影响心肌梗死和一些非缺血性心肌病的过程。在脂肪瘤性化生的情况下，T1偏差将是加性的或减性的，这取决于中心频率分别对应于心肌和脂肪是同相还是异相。重要的是要理解这一机制，否则可能导致错误的解释。
Quantitative measurement of T1 in the myocardium may be used to detect both focal and diffuse disease processes such as interstitial fibrosis or edema. A partial volume problem exists when a voxel in the myocardium also contains fat. Partial volume with fat occurs at tissue boundaries or within the myocardium in the case of lipomatous metaplasia of replacement fibrosis, which is commonly seen in chronic myocardial infarction. The presence of fat leads to a bias in T1 measurement. The mechanism for this artifact for widely used T1 mapping protocols using balanced steady state free precession readout and the dependence on off-resonance frequency are described in this paper. Simulations were performed to illustrate the behavior of mono-exponential fitting to bi-exponential mixtures of myocardium and fat with varying fat fractions. Both inversion recovery and saturation recovery imaging protocols using balanced steady state free precession are considered. In-vivo imaging with T1-mapping, water/fat separated imaging, and late enhancement imaging was performed on subjects with chronic myocardial infarction. In n = 17 subjects with chronic myocardial infarction, lipomatous metaplasia is evident in 8 patients (47%). Fat fractions as low as 5% caused approximately 6% T1 elevation for the out-of-phase condition, and approximately 5% reduction of T1 for the in-phase condition. T1 bias in excess of 1000 ms was observed in lipomatous metaplasia with fat fraction of 38% in close agreement with simulation of the specific imaging protocols. Measurement of the myocardial T1 by widely used balanced steady state free precession mapping methods is subject to bias when there is a mixture of water and fat in the myocardium. Intramyocardial fat is frequently present in myocardial scar tissue due lipomatous metaplasia, a process affecting myocardial infarction and some non-ischemic cardiomyopathies. In cases of lipomatous metaplasia, the T1 biases will be additive or subtractive depending on whether the center frequency corresponds to the myocardium and fat being in-phase or out-of-phase, respectively. It is important to understand this mechanism, which may otherwise lead to erroneous interpretation.
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影响因子：
3.3
作者：
Goldfarb, James W.
通讯作者：
Goldfarb, James W.
DOI：
10.1186/1532-429x-14-15
发表时间：
2012-02-06
期刊：
Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
影响因子：
--
作者：
Dall'Armellina E;Piechnik SK;Ferreira VM;Si QL;Robson MD;Francis JM;Cuculi F;Kharbanda RK;Banning AP;Choudhury RP;Karamitsos TD;Neubauer S
通讯作者：
Neubauer S
DOI：
10.1161/circimaging.113.001541
发表时间：
2014-05
期刊：
Circulation. Cardiovascular imaging
影响因子：
--
作者：
Kali A;Cokic I;Tang RL;Yang HJ;Sharif B;Marbán E;Li D;Berman DS;Dharmakumar R
通讯作者：
Dharmakumar R
影响因子：
3.3
作者：
Kellman, Peter;Hernando, Diego;Shah, Saurabh;Zuehlsdorff, Sven;Jerecic, Renate;Mancini, Christine;Liang, Zhi-Pei.;Arai, Andrew E.
通讯作者：
Arai, Andrew E.
影响因子：
6.7
作者：
Bauner, Kerstin Ulrike;Biffar, Andreas;Wintersperger, Bernd J.
通讯作者：
Wintersperger, Bernd J.