Boss Andreas, Martirosian Petros, Jehs Margit C, Dietz Klaus, Alber Markus, Rossi Cristina, Claussen Claus D, Schick Fritz
Section of Experimental Radiology, Eberhard-Karls University, Hoppe-Seyler-Strasse 3, Tübingen, Germany.
NMR Biomed. 2009 Jul;22(6):638-45. doi: 10.1002/nbm.1378.
The aim of the study was to assess the influence of carbogen (95% O(2), 5% CO(2)) or pure oxygen breathing on renal oxygenation measured by blood oxygenation level dependent (BOLD) magnetic resonance imaging at 3.0 T. Seven healthy young volunteers (median age 25, range 23-35 years) participated in the study. A T2*-weighted fat-saturated spoiled gradient-echo sequence was implemented on a 3.0 T whole-body imager (TE/TR = 27.9 ms/49 ms, excitation angle 20 degrees ) with an acquisition time of approximately 5.3 s. A total of 100 images were acquired during 22 min. A block design was applied for gas administration: 4 min room air, 4 min carbogen/oxygen, 4 min room air, 4 min carbogen/oxygen and 6 min room air. A compartment model was fitted to the data sets accounting for time-dependent increase/decrease of renal oxygenation as well as baseline changes of the scanner. T2*-weighted images showed good image quality without notable artefacts or distortions. Mean relative signal increase due to carbogen breathing was 2.73% (95% confidence interval: 1.34-5.54) in the right kidney and 3.76% (1.53-9.20) in the left kidney, while oxygen breathing led to a signal enhancement of 3.20% (2.57-3.98) in the right kidney and 3.16% (1.83-5.45) in the left kidney. No statistical difference was found between carbogen and oxygen breathing or between the oxygenation of the right and the left kidney. A significant difference was found in the characteristic time constant for the signal increase with a faster saturation taking place for oxygen breathing. Renal tissue oxygenation is clearly influenced by carbogen or oxygen breathing. The changes can be assessed by T2*-weighted MRI at high field strengths. The effects are in the expected range for the BOLD effect of 3-4% at 3.0 T. The proposed technique might be interesting for the assessment of renal tissue oxygenation and its regulation in patients with kidney diseases.
本研究的目的是评估通过3.0 T血氧水平依赖（BOLD）磁共振成像测量的卡波金（95% O₂，5% CO₂）或纯氧呼吸对肾脏氧合的影响。七名健康年轻志愿者（年龄中位数25岁，范围23 - 35岁）参与了该研究。在一台3.0 T全身成像仪上实施了T2 *加权脂肪饱和扰相梯度回波序列（TE/TR = 27.9 ms/49 ms，激发角20度），采集时间约为5.3秒。在22分钟内共采集了100幅图像。采用分组设计进行气体给予：4分钟室内空气、4分钟卡波金/氧气、4分钟室内空气、4分钟卡波金/氧气和6分钟室内空气。将一个房室模型拟合到数据集，以考虑肾脏氧合随时间的增加/减少以及扫描仪的基线变化。T2 *加权图像显示图像质量良好，无明显伪影或变形。卡波金呼吸导致右肾平均相对信号增加2.73%（95%置信区间：1.34 - 5.54），左肾增加3.76%（1.53 - 9.20），而纯氧呼吸导致右肾信号增强3.20%（2.57 - 3.98），左肾增强3.16%（1.83 - 5.45）。卡波金呼吸和纯氧呼吸之间或左右肾的氧合之间未发现统计学差异。在信号增加的特征时间常数方面发现了显著差异，纯氧呼吸时饱和更快。肾脏组织氧合明显受卡波金或纯氧呼吸的影响。这些变化可以通过高场强的T2 *加权MRI进行评估。在3.0 T时，这些效应处于预期的3 - 4%的BOLD效应范围内。所提出的技术可能对评估肾脏疾病患者肾脏组织氧合及其调节具有重要意义。
