Diffusion-Weighted MRI of the placenta in normal pregnancies and in pregnancies complicated by Fetal Growth Restriction
Author
Haals, Caroline Frederike
Term
5. Term (Master thesis)
Education
Publication year
2015
Submitted on
2015-12-21
Abstract
Objective: To evaluate placental apparent diffusion coefficient (ADC) values measured by diffusion-weighted imaging (DWI) in uncomplicated pregnancies and in pregnancies with fetal growth restriction (FGR, when the baby grows too little in the womb). Methods: We retrospectively reviewed 1.5T placental MRI from 38 singleton pregnancies. On the DWI sequence (b-values 200, 400, and 1000 s/mm2), regions of interest were drawn to cover the whole placenta across five slices, and a mean ADC was calculated. In pregnancies delivering neonates ≥ 2.3rd percentile, the relationship between ADC and gestational age at MRI was assessed with linear regression. In FGR pregnancies, ADC z-scores were calculated relative to the normal range. Results: Thirty-one pregnancies (20–37 weeks) resulted in neonates ≥ 2.3rd percentile. In these, placental ADC ranged from 1.33 to 1.76 x10-3 mm2/s and showed a significant inverse correlation with gestational age (p=0.001). In seven FGR pregnancies (27–37 weeks), ADC z-scores ranged from 1.10 to -2.80; in three cases ADC was markedly reduced, while in four it was within the normal range. Conclusion: In normal pregnancy, placental ADC decreases as gestation advances. In FGR, placental abnormalities did not consistently affect ADC values.
Formål: At vurdere moderkagens apparente diffusionskoefficient (ADC) målt med diffusionvægtet MR (DWI) i normale graviditeter og graviditeter med føtal væksthæmning (FGR, hvor barnet vokser for lidt i livmoderen). Metode: Vi gennemgik retrospektivt 1,5T MR-skanninger af moderkagen fra 38 enkeltgraviditeter. I DWI-sekvensen (b-værdier 200, 400 og 1000 s/mm2) blev interesseområder tegnet, så fem snit dækkede hele moderkagen, og et gennemsnitligt ADC blev beregnet. I graviditeter med nyfødt fødselsvægt ≥ 2,3-percentilen blev sammenhængen mellem ADC og gestationsalder ved MR estimeret med lineær regression. I FGR-forløb blev ADC z-scorer beregnet i forhold til normalområdet. Resultater: 31 graviditeter (20–37 uger) endte med nyfødte ≥ 2,3-percentilen. Her lå moderkagens ADC mellem 1,33 og 1,76 x10-3 mm2/s og var omvendt korreleret med gestationsalderen (p=0,001). I syv FGR-graviditeter (27–37 uger) lå ADC z-scorer mellem 1,10 og -2,80; i tre tilfælde var ADC tydeligt nedsat, mens det i fire lå inden for normalområdet. Konklusion: I normale graviditeter falder moderkagens ADC med stigende gestationsalder. Ved FGR påvirker forandringer i den svigtende moderkage ikke ADC-værdien konsekvent.
[This abstract has been rewritten with the help of AI based on the project's original abstract]