1. ESTIMATION OF PLACENTA FUNCTION USING T 2* MEASUREMENTS DURING HYPER- AND NORMOXIA May 9 th, 12 am, Computer no 73 Mother + O 2 mask Mother w/o mask 4142 0102030100405060708090

2. ESTIMATION OF PLACENTA FUNCTION USING T 2* MEASUREMENTS DURING HYPER- AND NORMOXIA 4142 David Alberg Peters Department of Clinical Engineering, Central Denmark Region, Aarhus, Denmark David.Peters@stab.rm.dk Anne Sørensen Department of Obstetrics and Gynecology, Aarhus University, Aalborg Hospital, Denmark Torben Fründ Department of Radiology, Aarhus University, Aalborg Hospital, De nmark Ole Bjarne Christiansen Department of Obstetrics and Gynecology, Aarhus University, Aalborg Hospital, Denmark Niels Uldbjerg Department of Obstetrics and Gynecology, Aarhus University Hospital, Denmark. May 9 th, 12 am, Computer no 73

3. Materials 6 x g.w. 28-35 MATLAB

4. Protocol Localizer Multi Echo GE 10 min Multi Echo GE Bold imaging (separate study)  Multi Echo GE  TR=70.9ms, TE=3.02 to 67.5 ms – step 4.3 ms.  FOV 350x350 mm, Matrix 256 x 128, Three 8 mm slices Normoxia (21% O 2 )Hyperoxia (100% O 2 )

5. Acquisition Multi Echo GE sequence - Increasing TE Placenta ROI

6. Processing  T 2* fitted (Levenberg Marquardt implemented in MATLAB)  Fitted either Pixel by pixel or in a region of interest (ROI)

7. Results (ROI based fitting) Subject 1 Subject 2 Subject 3 Subject 4-5-6 Mean change (P<0.01)

8. Results (Pixel by pixel fitting) 0102030100405060708090 NormoxicHyperoxic T2* (ms)

9. Conclusion  T 2* increases significantly in the placenta when the mother breathes oxygen  The change in T 2* is inhomogeneously distributed in the placenta  The change in T 2* is most likely caused by a change in the pO 2 of the blood in placenta

10. Placenta structure Fetal placenta Maternal placenta

11. Discussion Correspondance between “blue” areas in pre oxygen T 2* map and fetal side of placenta? Same?

12. Discussion  Is the difference between hyperoxic and normoxic placenta T 2* value an indicator of placenta function?  Is a reduced response sign of a poorly functioning placenta?