Measurement of renal tissue oxygenation with blood oxygen level-dependent MRI and oxygen transit modeling
Measurement of renal tissue oxygenation with blood oxygen level-dependent MRI and oxygen transit modeling
复制标题
DOI：
10.1152/ajprenal.00575.2013
复制
发表时间：
2014-03-01
影响因子：
4.2
通讯作者：
Lee, Vivian S.
中科院分区：
文献类型：
--
作者：
Zhang, Jeff L.;Morrell, Glen;Lee, Vivian S.
肾脏的血氧水平依赖性（BOLD）MRI数据虽然指示组织氧合水平（PO 2），但实际上受到多种混杂因素的影响，如R-2、灌注、氧渗透性和血细胞比容。我们的目的是探讨从肾脏BOLD数据中提取组织PO 2的可行性。提出了一种两步的方法：首先，蒙特卡罗模拟从BOLD信号估计血氧饱和度（SHb），第二，氧传输模型将SHb转换为组织PO 2。所提出的方法进行了校准和验证与20头猪（12呋塞米注射前后），其中BOLD衍生的组织PO 2与微探针测量值进行了比较。然后将该方法应用于9名健康人受试者（年龄：25.7 +/- 3.0岁），其中在速尿之前和之后进行BOLD。对于注射呋塞米前的12只猪，与微探针测量相比，所提出的模型估计肾组织PO 2，皮质中的误差为2.3 +/- 5.2 mmHg（5.8 +/- 13.4%），髓质中的误差为-0.1 +/- 4.5 mmHg（1.7 +/- 18.1%）。注射呋塞米后，皮质和髓质的估计误差分别为6.9 ± 3.9 mmHg（14.2 ± 8.4%）和2.6 ± 4.0 mmHg（7.7 ± 11.5%）。在人类受试者中，BOLD衍生的髓质PO 2从基线时的16.0 +/- 4.9 mmHg（SHb：31 +/- 11%）增加至呋塞米注射后5分钟的26.2 +/- 3.1 mmHg（SHb：53 +/- 6%），而皮质PO 2在58 mmHg（SHb：92 +/- 1%）时无显著变化。我们提出的方法，验证了猪模型，似乎有前途的估计组织PO 2从肾脏BOLD MRI数据在人类受试者。
Blood oxygen level-dependent (BOLD) MRI data of kidney, while indicative of tissue oxygenation level (PO2), is in fact influenced by multiple confounding factors, such as R-2, perfusion, oxygen permeability, and hematocrit. We aim to explore the feasibility of extracting tissue PO2 from renal BOLD data. A method of two steps was proposed: first, a Monte Carlo simulation to estimate blood oxygen saturation (SHb) from BOLD signals, and second, an oxygen transit model to convert SHb to tissue PO2. The proposed method was calibrated and validated with 20 pigs (12 before and after furosemide injection) in which BOLD-derived tissue PO2 was compared with microprobe-measured values. The method was then applied to nine healthy human subjects (age: 25.7 +/- 3.0 yr) in whom BOLD was performed before and after furosemide. For the 12 pigs before furosemide injection, the proposed model estimated renal tissue PO2 with errors of 2.3 +/- 5.2 mmHg (5.8 +/- 13.4%) in cortex and -0.1 +/- 4.5 mmHg (1.7 +/- 18.1%) in medulla, compared with microprobe measurements. After injection of furosemide, the estimation errors were 6.9 +/- 3.9 mmHg (14.2 +/- 8.4%) for cortex and 2.6 +/- 4.0 mmHg (7.7 +/- 11.5%) for medulla. In the human subjects, BOLD-derived medullary PO2 increased from 16.0 +/- 4.9 mmHg (SHb: 31 +/- 11%) at baseline to 26.2 +/- 3.1 mmHg (SHb: 53 +/- 6%) at 5 min after furosemide injection, while cortical PO2 did not change significantly at similar to 58 mmHg (SHb: 92 +/- 1%). Our proposed method, validated with a porcine model, appears promising for estimating tissue PO2 from renal BOLD MRI data in human subjects.