通过动态对比增强磁共振成像评估子宫缺血模型中的胎盘灌注情况。
Placental perfusion in uterine ischemia model as evaluated by dynamic contrast enhanced MRI.
作者信息
Drobyshevsky Alexander, Prasad P V
机构信息
Department of Pediatrics NorthShore.
Radiology, NorthShore University HealthSystem, Evanston, IL.
出版信息
J Magn Reson Imaging. 2015 Sep;42(3):666-72. doi: 10.1002/jmri.24830. Epub 2015 Apr 9.
BACKGROUND
To validate DCE MRI method of placental perfusion estimation and to demonstrate application of the method in a rabbit model of fetal antenatal hypoxia-ischemia.
METHODS
Placental perfusion was estimated by dynamic contrast imaging with bolus injection of Gd-DTPA in 3 Tesla GE magnet in a rabbit model of placental ischemia-reperfusion in rabbit dams at embryonic day 25 gestation age. Placental perfusion was measured using steepest slope method on DCE MRI before and after intermittent 40 min uterine ischemia. Antioxidants (n = 2 dams, 9 placentas imaged) or vehicle (n = 5 dams, 23 placenta imaged) were given systemically in a separate group of dams during reperfusion-reoxygenation. Placental perfusion was also measured in two dams from the antioxidant group (10 placentas) and two dams from the control group (12 placentas) by fluorescent microspheres method.
RESULTS
While placental perfusion estimates between fluorescent microspheres and DCE MRI were significantly correlated (R(2) = 0.85; P < 0.01), there was approximately 33% systematic underestimation by the latter technique. DCE MRI showed a significant decrease in maternal placental perfusion in reperfusion-reoxygenation phase in the saline, 0.44 ± 0.06 mL/min/g (P = 0.012, t-test), but not in the antioxidant group, 0.62 ± 0.06 mL/min/g, relative to pre-occlusion values (0.77 ± 0.07 and 0.84 ± 0.12 mL/min/g, correspondingly).
CONCLUSION
Underestimation of true perfusion in placenta by steepest slope DCE MRI is significant and the error appears to be systematic.
背景
验证胎盘灌注评估的动态对比增强磁共振成像（DCE MRI）方法，并展示该方法在胎儿产前缺氧缺血兔模型中的应用。
方法
在妊娠第25天的兔母体胎盘缺血再灌注模型中，于3特斯拉GE磁体中通过团注钆喷酸葡胺进行动态对比成像来评估胎盘灌注。在间歇性40分钟子宫缺血前后，采用DCE MRI上的最陡斜率法测量胎盘灌注。在再灌注 - 复氧期间，对另一组母兔全身给予抗氧化剂（n = 2只母兔，成像9个胎盘）或赋形剂（n = 5只母兔，成像23个胎盘）。还通过荧光微球法测量了抗氧化剂组的2只母兔（10个胎盘）和对照组的2只母兔（12个胎盘）的胎盘灌注。
结果
虽然荧光微球法和DCE MRI法之间的胎盘灌注评估显著相关（R² = 0.85；P < 0.01），但后一种技术存在约33%的系统性低估。DCE MRI显示，在再灌注 - 复氧阶段，生理盐水组母体胎盘灌注显著降低，为0.44±0.06 mL/min/g（P = 0.012，t检验），而抗氧化剂组相对于闭塞前值（分别为0.77±0.07和0.84±0.12 mL/min/g）未出现显著降低，为0.62±0.06 mL/min/g。
结论
最陡斜率DCE MRI对胎盘真实灌注的低估显著，且误差似乎是系统性的。
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