• Kirstine Hansen Baadsgaard
5. Term (Master thesis), Medicine, Master (Master Programme)
Objective: The transversal relaxation time (T2*) is related to tissue oxygenation and morphology. It is well described in relation to in vivo oxygenation in the placenta, but this method is yet unexplored in fetal organs. The objective of this study was to investigate the T2* value of selected fetal organs and the association with low birth weight (BW). Methods: This prospective cohort study included 114 singleton pregnancies with Magnetic Resonance Imaging (MRI) performed between gestational week 23+6 and 41+3. T2* value was obtained from the fetal brain, lungs, heart, liver, kidneys, and spleen. The correlation between T2* value and gestational age (GA) at MRI was estimated by linear regression analysis and Pearson’s correlation coefficients. The association between low BW (BW ≤-22.0%) and T2* value of selected fetal organs was investigated by logistic regression adjusted for GA at MRI. Results: Out of 114 pregnancies 26.3% (n=30) had low BW. In normal BW pregnancies the T2* value in fetal organs showed a negative linear correlation with GA at MRI. This was significant for fetal brain (R2=0.69, P<0.001), fetal heart (R2=0.47, P<0.001), fetal kidneys (R2=0.67, P<0.001) and fetal spleen (R2=0.45, P<0.001), while statistical insignificant for fetal lungs (R2=0.14, P=0.198) and fetal liver (R2=0.14, P=0.222). Logistic regression demonstrated a significantly lower T2* value among fetuses with low BW. This association was significant for fetal heart (mean z-score =-3.23, P=0.001), fetal kidneys (mean z-score =-2.84, P=0.005) and fetal spleen (mean z-score =-2.60, P=0.009). However, insignificant in the fetal brain (mean z-score =-0.62, P=0.538), fetal lungs (mean z-score =-1.94, P=0.053) and fetal liver (mean z-score =-0.38, P=0.706). Conclusion: Low T2* values of selected fetal organs in low BW pregnancies may be a result of tissue hypoxia and morphological changes related to placental insufficiency and supported by the T2* value being related to tissue oxygenation. In conclusion, this method can potentially contribute to non-invasive knowledge of fetal physiology during hypoxia and assessment of oxygenation within the fetus.
Publication date31 Dec 2019
Number of pages19
ID: 318412018