Department of Radiology, The Third People's Hospital of Shenzhen, The Second Affiliated Hospital of Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, Guangdong Province, China.
Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
NMR Biomed. 2021 Mar;34(3):e4449. doi: 10.1002/nbm.4449. Epub 2020 Dec 22.
The aim of this study was to establish reference values for middle-aged subjects and to investigate the age and gender dependence of liver diffusion MRI parameters. The IVIM type of liver diffusion scan was based on a single-shot spin-echo-type echo-planar sequence using a 1.5 T magnet with 16 b-values. Diffusion-derived vessel density (DDVD)(b0b2) or DDVD(b0b10) was the signal difference between b = 0 and b = 2 (or b = 10) s/mm images after removing visible vessels. IVIM analysis was performed with full fitting and segmented fitting, and with a threshold b-value of 60 or 200 s/mm , and fitting started from b = 2 s/mm . Thirty-one men (age range: 25-71 years) and 26 men (age: 22-69 years) had DDVD and IVIM analysis, respectively, while 37 women (age: 20-71 years) and 36 women (age: 20-71 years) had DDVD and IVIM analysis, respectively. DDVD results showed a significant age-related reduction for women. IVIM results for full fitting showed excellent agreement with those for segmented fitting using a threshold b of 60 s/mm , but this was less good for results with a threshold b of 200 s/mm . As age increased, female subjects' D measure showed a significant reduction, while their PF and D measures showed a significant increase. For the age group of 40-55 years, DDVD(b0b2), DDVD(b0b10), D , PF and D were 12.26 ± 3.90 au/pixel, 16.95 ± 5.45 au/pixel, 1.072 ± 0.067 (10 mm /s), 0.141 ± 0.025 and 61.0 ± 14.0 (10 mm /s) for men, and 13.35 ± 3.6 au/pixel, 17.20 ± 3.62 au/pixel, 1.069 ± 0.074 (10 mm /s), 0.119 ± 0.014 and 57.1 ± 13.2 (10 mm /s) for women, respectively. DDVD measure of this study suggest that aging is associated with a reduction in liver perfusion. There is a possibility that a lower D measure is associated with artificially higher PF and D measures, and that IVIM modeling of the perfusion component is constrained by the diffusion component.
本研究旨在建立中年人群的参考值，并探讨肝脏弥散 MRI 参数的年龄和性别依赖性。肝脏弥散扫描的 IVIM 类型基于单次激发自旋回波型回波平面序列，使用 1.5 T 磁体，b 值为 16。弥散衍生血管密度（DDVD）（b0b2）或 DDVD（b0b10）是 b = 0 和 b = 2（或 b = 10）s/mm 图像之间的信号差，在去除可见血管后。IVIM 分析采用全拟合和分段拟合，以及 b 值为 60 或 200 s/mm 的阈值进行拟合，拟合从 b = 2 s/mm 开始。31 名男性（年龄范围：25-71 岁）和 26 名男性（年龄：22-69 岁）分别进行了 DDVD 和 IVIM 分析，而 37 名女性（年龄：20-71 岁）和 36 名女性（年龄：20-71 岁）分别进行了 DDVD 和 IVIM 分析。DDVD 结果显示女性与年龄相关的降低具有统计学意义。全拟合的 IVIM 结果与使用 60 s/mm 阈值的分段拟合结果具有极好的一致性，但使用 200 s/mm 阈值时则不太好。随着年龄的增长，女性受试者的 D 测量值显著降低，而 PF 和 D 测量值显著增加。对于 40-55 岁年龄组，DDVD（b0b2）、DDVD（b0b10）、D、PF 和 D 分别为 12.26±3.90 au/pixel、16.95±5.45 au/pixel、1.072±0.067（10mm/s）、0.141±0.025 和 61.0±14.0（10mm/s）男性，13.35±3.6 au/pixel、17.20±3.62 au/pixel、1.069±0.074（10mm/s）、0.119±0.014 和 57.1±13.2（10mm/s）女性。本研究的 DDVD 测量值表明，衰老与肝脏灌注减少有关。可能存在较低的 D 测量值与人为较高的 PF 和 D 测量值相关，并且灌注成分的 IVIM 建模受到扩散成分的限制。
