基于大鼠肾脏阶跃氧刺激的高时间分辨率动态T2*W成像研究

doi:10.12122/j.issn.1673-4254.2026.01.22

南方医科大学学报 ›› 2026, Vol. 46 ›› Issue (1): 200-207.doi: 10.12122/j.issn.1673-4254.2026.01.22

基于大鼠肾脏阶跃氧刺激的高时间分辨率动态T₂*W成像研究

孙送送¹^,²(), 陶泉¹^,², 赵凯旋³, 胡秋根⁴, 冯衍秋¹^,²^,⁴()

^1.南方医科大学，生物医学工程学院，广东广州 510515
^2.南方医科大学，广东省医学图像处理重点实验室//广东省医学影像与诊断技术工程实验室，广东广州 510515
^3.南方医科大学第三附属医院，广东省骨科研究院，广东广州 510630
^4.南方医科大学第八附属医院（顺德第一人民医院）放射科，广东佛山 528308

收稿日期:2025-07-20 出版日期:2026-01-20 发布日期:2026-01-16
通讯作者: 冯衍秋 E-mail:sunsongsong02@163.com;foree@163.com
作者简介:孙送送，在读硕士研究生，E-mail: sunsongsong02@163.com
基金资助:
国家自然科学基金(82372079);国家自然科学基金联合基金(U21A6005);广东省自然科学基金(2024A1515010014);广东省基础与应用基础研究基金(2023A1515110614)

A high temporal resolution dynamic T₂*W imaging study based on step oxygen stimulation of rat kidneys

Songsong SUN¹^,²(), Quan TAO¹^,², Kaixuan ZHAO³, Qiugen HU⁴, Yanqiu FENG¹^,²^,⁴()

^1.School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
^2.Guangdong Provincial Key Laboratory of Medical Image Processing & Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou 510515, China
^3.Guangdong Provincial Orthopedic Research Institute, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
^4.Department of Radiology, Eighth Affiliated Hospital of Southern Medical University (Shunde First People's Hospital), Foshan 528308, China

Received:2025-07-20 Online:2026-01-20 Published:2026-01-16
Contact: Yanqiu FENG E-mail:sunsongsong02@163.com;foree@163.com
Supported by:
National Natural Science Foundation of China(82372079)

摘要/Abstract

摘要：

目的通过高时间分辨率动态T₂*加权平面回波成像（T₂*W-EPI）监测大鼠肾脏在阶跃氧刺激下的氧合水平变化。方法对SD大鼠（n=10）施加2 min高氧（100% O₂）-10 min低氧（10% O₂）-10 min高氧（100% O₂）的阶跃氧刺激，在9.4 T小动物磁共振扫描仪上连续采集多回波梯度回波序列（mGRE）及梯度回波-平面回波成像（EPI）序列的肾脏动态MRI数据，2种序列的时间分辨率分别为9 s、1 s。对大鼠肾脏不同感兴趣区域（ROI）的动态时间序列曲线建立二阶阶跃响应模型，并定量得到阶跃响应模型参数，包括时间延迟∆t、自然频率 $ω n$ 、阻尼常数D及振荡周期T。通过对比模型参数差异来比较2种不同时间分辨率的MRI成像方法对肾脏阶跃氧刺激响应的表现。结果与mGRE的对照实验结果相比，本研究提出的动态T₂*W-EPI技术将监测肾脏阶跃氧刺激的成像时间分辨率提升了8倍，并提高了阶跃响应模型拟合优度；且模型有更优的表现，包括更短的时间延迟∆t（在皮质、外髓外带、外髓内带、内髓质分别缩短29.4%、42.6%、56.4%、47.4%），更大的自然频率 $ω n$ （分别增加21.1%、28.6%、52.2%、61.9%），以及各个ROI在阶跃氧刺激下的振荡恢复（阻尼常数D<1）。结论对于大鼠肾脏的阶跃氧刺激模型，本研究提出的高时间分辨率动态T₂*W-EPI技术可以实时监测到肾脏组织内更快的氧合水平变化，为肾脏异常状态的检测提供了潜在的指标。

关键词: 平面回波成像, 阶跃氧刺激, 肾脏, 氧合水平

Abstract:

Objective To monitor the changes in oxygenation levels of rat kidneys under step oxygen stimulation by high temporal resolution dynamic T₂* weighted planar echo imaging (T₂*W-EPI). Methods Step oxygen stimulation was applied to SD rats (n=10) in the sequence of 2 min of hyperoxia (100% O₂) -10 min of hypoxia (10% O₂) -10 min of hyperoxia (100% O₂). Dynamic MRI data of the kidneys of multi-echo gradient echo (mGRE) sequence and gradient echo-planar imaging (EPI) sequence were continuously acquired on a 9.4T small animal magnetic resonance scanner. The time resolution of the two sequences were 9 s and 1 s, respectively. A second-order step response model was established for the dynamic time series curves of different regions of interest (ROIs) in rat kidneys, and the parameters of the step response model were obtained, including time delay ∆t, natural frequency ωn, damping constant D and oscillation period T. The performance of two MRI imaging methods with different temporal resolution in response to the step oxygen stimulation in the kidneys was compared. Results Compared with the control experiment results of mGRE, the dynamic T₂*W-EPI technology proposed in this study increased the temporal resolution of monitoring renal step oxygen stimulation by 8 folds and improved the goodness of fit of the step response model. The model showed a shorter time delay ∆t (shortened by 29.4%, 42.6%, 56.4%, and 47.4%, respectively, in the CO, OSOM, ISOM and IM), a larger natural frequency ωn (increased by 21.1%, 28.6%, 52.2%, and 61.9%, respectively), and oscillation of each ROI (damping constant D<1) under the step oxygen stimulation. Conclusion In a step oxygen stimulation model of rat kidneys, the high temporal resolution dynamic T₂*W-EPI technique proposed in this study is capable of real-time monitoring of the changes in renal oxygenation levels for detection of abnormal renal conditions.

Key words: echo planar imaging, step oxygen stimulation, kidney, oxygenation

孙送送, 陶泉, 赵凯旋, 胡秋根, 冯衍秋. 基于大鼠肾脏阶跃氧刺激的高时间分辨率动态T₂*W成像研究[J]. 南方医科大学学报, 2026, 46(1): 200-207.

Songsong SUN, Quan TAO, Kaixuan ZHAO, Qiugen HU, Yanqiu FENG. A high temporal resolution dynamic T₂*W imaging study based on step oxygen stimulation of rat kidneys[J]. Journal of Southern Medical University, 2026, 46(1): 200-207.

图/表 6

表1 各序列具体的MR扫描参数

Tab.1 MR scan parameters for each sequence

MR scan sequence	RARE	mGRE	FID-EPI
TE (ms)	45	2-33.05 (∆TE=2.07)	8.458
TR (ms)	3500	40.553	1000
FA (°)	-	15	60
FOV (mm²)	55×55	55×55	55×55
Matrix size	110×110	110×110	110×110
Slice thickness (mm)	1	1	1
Resolution (mm²)	0.5×0.5	0.5×0.5	0.5×0.5
Averages	2	1	1
Rare factor	16	-	-
Bandwidth (kHz)	-	-	666.7
Scan time (s)	42	9	1

图1 二阶连续时间系统的阶跃响应模型

Fig.1 Step response models for the second-order continuous-time system. A: Step response of the second-order system and the significance of its model parameters. B: Step response of the second-order system corresponding to different damping constants D. C: Step response of the second-order system corresponding to different natural frequencies ωn.

图2 肾脏系统的阶跃响应示意图

Fig.2 Schematic diagram of the step response of the renal system.

图3 在大鼠肾脏T2WI上勾画ROI(CO蓝色, OSOM黄色, ISOM绿色, IM红色)以及气体刺激时序图和在气体刺激各阶段对应的T2*map和T2*WI

Fig.3 Placement of ROIs on T2WI obtained from MRI (A) and gas challenge protocol, T2*map and T2*WI acquired at each stage of gas challenge (B). ROI placement 4 anatomical layers of kidney-CO (blue), OSOM (yellow), ISOM (green), and IM (red) were used.

图4 大鼠肾脏CO, OSOM, ISOM及IM的动态时间序列曲线

Fig.4 Dynamic T2* sequence curves (A) and dynamic T2*W signal sequence curves (B) in renal CO, OSOM, ISOM and IM of the same rat. The yellow and green arrows represent the overshoot phenomena of OSOM and ISOM, respectively.

图5 mGRE和FID-EPI序列的动态数据的模型参数分析

Fig.5 Model parameter analysis of dynamic data of mGRE and FID-EPI sequences. A: Model parameter maps of mGRE. B: Model parameter maps of FID-EPI. C: Comparison of model parameters. ****P<0.0001 vs mGRE.

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基于大鼠肾脏阶跃氧刺激的高时间分辨率动态T₂*W成像研究

A high temporal resolution dynamic T₂*W imaging study based on step oxygen stimulation of rat kidneys

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