T2 and T2* measurements of fetal brain oxygenation during hypoxia with MRI at 3T: correlation with fetal arterial blood oxygen saturation.
The purpose of this prospective study was to determine the oxygen saturation of blood in the fetal brain based on T2 and T2* measurements in a fetal sheep model. Five sheep fetuses were investigated during normoxia and hypoxia by 3T MRI. Multi-echo gradient-echo and turbo-spin-echo sequences were performed on the fetal brain. MR-determined oxygen saturation (MR-sO(2)) of blood in the fetal brain was calculated based on T2 and T2* values. Fetal arterial blood oxygen saturation (blood-sO(2)) was measured during the two experimental phases. The slope of MR-sO(2) as a function of blood-sO(2) was estimated and tested for compatibility using the one-sample t-test. During normoxia, mean values for carotid blood oxygen saturation were 67%, 83 ms for T2*, 202 ms for T2 and 96% for MR-sO(2). During hypoxia, arterial blood oxygen saturation, T2* and calculated MR-sO(2) decreased to 22%, 64 ms, and 68% respectively. The one-sample t-test revealed the slope to be significantly different from 0 (T = 5.023, df = 4, P = 0.007). It is feasible to perform quantitative T2 and T2* measurements in the fetal brain. MR-sO(2) and fetal arterial blood oxygen saturation correlated significantly. However, based on these data a reliable quantification of fetal brain tissue oxygenation is not possible.
Wedegärtner
Ulrike
U
Department of Diagnostic and Interventional Radiology, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg, Germany. wedegaer@uke.uni-hamburg.de
Kooijman
Hendrik
H
Andreas
Thomas
T
Beindorff
Nicola
N
Hecher
Kurt
K
Adam
Gerhard
G
D000818:Animals; D001158:Arteries / Q000196:embryology / Q000378:metabolism*; D001921:Brain / Q000196:embryology / Q000378:metabolism*; D005311:Fetal Hypoxia / Q000175:diagnosis / Q000378:metabolism*; D002534:Hypoxia, Brain / Q000175:diagnosis / Q000378:metabolism*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012756:Sheep; D013223:Statistics as Topic
D010100:Oxygen