Assessment of the Placenta in Intrauterine Growth Restriction by Diffusion-Weighted Imaging and Proton Magnetic Resonance Spectroscopy: A Pilot Study

Placental insufficiency is a major cause of intrauterine growth restriction (IUGR) and seriously affects fetal development. When placental insufficiency happened, the diffusion of water molecule was restricted and the metabolic balance was destroyed in the placenta. In this prospective study, we aimed to evaluate the diagnostic value of diffusion-weighted imaging (DWI) in combination with proton magnetic resonance spectroscopy (H-1 MRS) for placental insufficiency in IUGR. The apparent diffusion coefficient (ADC) values were calculated using DWI, and the metabolism of N-acetylaspartate (NAA), choline, and lipid and their ratios in the placenta were calculated using H-1 MRS. Data were statistically analyzed by receiver operating characteristic (ROC) curves and logistic regression analysis. The NAA and choline peaks were decreased in IUGR placentas compared with normal placentas, while lipid peaks showed an opposite trend. The average ADC value and the NAA/lipid and choline/lipid ratios were lower in the IUGR group than in the normal group (P < .01). Logistic regression with multiple parameters showed that combination of the ADC value and choline/lipid ratio was more favorable than either parameter alone in analyzing placental insufficiency of IUGR (P < .05). The area under the ROC curve for the combination was 0.939, indicating reasonably good discrimination. We concluded that reduced ADC and NAA/lipid and choline/lipid ratios could serve as potential markers for placental insufficiency of IUGR. Furthermore, the combination of ADC value and choline/lipid ratio greatly improved the diagnostic value.