摘要
目的通过高时间分辨率动态T_(2)^(*)加权平面回波成像(T_(2)^(*)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%O_(2))-10 min低氧(10%O_(2))-10 min高氧(100%O_(2))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Δt、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T_(2)^(*)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Δt(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T_(2)^(*)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。
Objective To monitor the changes in oxygenation levels of rat kidneys under step oxygen stimulation by high temporal resolution dynamic T_(2)^(*)weighted planar echo imaging(T_(2)^(*)W-EPI).Methods Step oxygen stimulation was applied to SD rats(n=10)in the sequence of 2 min of hyperoxia(100%O_(2))-10 min of hypoxia(10%O_(2))-10 min of hyperoxia(100%O_(2)).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 delayΔt,natural frequencyω_(n),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 T_(2)^(*)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 delayΔt(shortened by 29.4%,42.6%,56.4%,and 47.4%,respectively,in the CO,OSOM,ISOM and IM),a larger natural frequencyω_(n)(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 T_(2)^(*)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.
作者
孙送送
陶泉
赵凯旋
胡秋根
冯衍秋
SUN Songsong;TAO Quan;ZHAO Kaixuan;HU Qiugen;FENG Yanqiu(School of Biomedical Engineering,Southern Medical University,Guangzhou 510515,China;Guangdong Provincial Key Laboratory of Medical Image Processing&Guangdong Province Engineering Laboratory for Medical Imaging and Diagnostic Technology,Southern Medical University,Guangzhou 510515,China;Guangdong Provincial Orthopedic Research Institute,Third Affiliated Hospital of Southern Medical University,Guangzhou 510630,China;Department of Radiology,Eighth Affiliated Hospital of Southern Medical University(Shunde First People's Hospital),Foshan 528308,China)
出处
《南方医科大学学报》
北大核心
2026年第1期200-207,共8页
Journal of Southern Medical University
基金
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)。
关键词
平面回波成像
阶跃氧刺激
肾脏
氧合水平
echo planar imaging
step oxygen stimulation
kidney
oxygenation
