验证两种新生儿脑静脉氧合(Yv)MRI技术,相位对比(TRUPC)和加速TRUPC(aTRUPC)MRI下的T2弛豫,用直接采血测量氧合。
对7只健康新生仔猪进行体内实验。每只小猪,在上矢状窦内放置一根导管,获取静脉血样,作为血液气体血氧饱和度测量的金标准.在核磁共振实验中,通过改变吸入O2含量和呼吸频率,每只仔猪可达到3至5个静脉氧合水平。在每种情况下,通过TRUPC测量上矢状窦的Yv值,aTRUPC,并获得血气血氧饱和度。TRUPC和aTRUPC中的Yv定量使用标准牛血校准模型。将aTRUPC扫描重复两次以评估其再现性。TRUPCYv之间的协议,aTRUPCYv,通过组内相关系数(ICC)和配对的学生t检验评估血气氧饱和度。
仔猪的平均血细胞比容为23.6±6.5%。在所有测量中,Yv值为51.9±21.3%,54.1±18.8%,和53.7±19.2%的血气血氧饱和度,TRUPC和aTRUPC,分别,两种方法均无显著性差异(P>3)。TRUPC与血气Yv有良好的相关性(ICC=0.801;P<0.0001),在ATRUPC和血气Yv之间(ICC=0.809;P<0.0001),在aTRUPC和TRUPCYv之间(ICC=0.887;P<0.0001)。aTRUPCYv的变异系数为8.1±9.9%。
TRUPC和aTRUPC测得的Yv值与血气血氧饱和度吻合良好。这些发现表明,TRUPC和aTRUPC可以提供脑主要静脉中Yv的准确定量。
To validate two neonatal cerebral venous oxygenation (Yv ) MRI techniques, T2 relaxation under phase contrast (TRUPC) and accelerated TRUPC (aTRUPC) MRI, with oxygenation measured with direct blood sampling.
In vivo experiments were performed on seven healthy newborn piglets. For each
piglet, a catheter was placed in the superior sagittal sinus to obtain venous blood samples for blood gas oximetry measurement as a gold standard. During the MRI experiment, three to five venous oxygenation levels were achieved in each
piglet by varying inhaled O2 content and breathing rate. Under each condition, Yv values of the superior sagittal sinus measured by TRUPC, aTRUPC, and blood gas oximetry were obtained. The Yv quantification in TRUPC and aTRUPC used a standard bovine blood calibration model. The aTRUPC scan was repeated twice to assess its reproducibility. Agreements among TRUPC Yv , aTRUPC Yv , and blood gas oximetry were evaluated by intraclass correlation coefficient (ICC) and paired Student\'s t-test.
The mean hematocrit was 23.6 ± 6.5% among the piglets. Across all measurements, Yv values were 51.9 ± 21.3%, 54.1 ± 18.8%, and 53.7 ± 19.2% for blood gas oximetry, TRUPC and aTRUPC, respectively, showing no significant difference between any two methods (P > .3). There were good correlations between TRUPC and blood gas Yv (ICC = 0.801; P < .0001), between aTRUPC and blood gas Yv (ICC = 0.809; P < .0001), and between aTRUPC and TRUPC Yv (ICC = 0.887; P < .0001). The coefficient of variation of aTRUPC Yv was 8.1 ± 9.9%.
The values of Yv measured by TRUPC and aTRUPC were in good agreement with blood gas oximetry. These findings suggest that TRUPC and aTRUPC can provide accurate quantifications of Yv in major cerebral veins.