MRI prognosticators for adverse maternal and neonatal clinical outcome in patients at high risk for placenta accreta spectrum (PAS) disorders.

BACKGROUND

Placenta accreta spectrum (PAS) disorders may be associated with significant mortality and morbidity for both mother and fetus.

PURPOSE/HYPOTHESIS: To identify MRI risk factors for poor peripartum outcome in gravid patients at risk for PAS.

STUDY TYPE: Prospective.

POPULATION: One hundred gravid women (mean age: 34.9 years) at third trimester, with placenta previa.

FIELD STRENGTH/SEQUENCE: T2 -SSTSE (single-shot turbo spin echo), T2 -TSE, T1 -TSEFS (TSE images with fat-suppression) at 1.5T.

ASSESSMENT: Fifteen MRI features considered indicative of PAS were recorded by three radiologists and were tested for any association with the following adverse peripartum maternal and neonatal events: increased operation time, profound blood loss, hysterectomy, bladder repair, ICU admission, prematurity, low birthweight, and 5-minute APGAR score <7.

STATISTICAL TESTS: Kappa (K) coefficients were computed as a measure of agreement between intraoperative information/histology and MRI results as well as for interobserver agreement; chi-square and Fisher's exact tests were used to explore the association of the MRI signs with clinical complications. A score was calculated by adding all recorded MRI signs and its predictive ability was tested using receiver operating characteristic (ROC) analysis, against all complications, separately; odds ratios (ORs) for optimal cutoffs were determined with logistic regression analysis.

RESULTS

There was excellent agreement (K >0.75, P < 0.001) between MRI and intraoperative findings for invasive placenta, bladder and parametrial involvement. Intraplacental T2 dark bands, myometrial disruption, uterine bulge, and hypervascularity at the utero-placental interface or parametrium, showed significant association (P < 0.005) with poor clinical outcome for both mother and fetus. The MRI score showed significant predictive ability for each adverse maternal event (area under the curve [AUC]: 0.85-0.97, P < 0.001). The presence of ≥3 MRI signs was the cutoff point for a complicated delivery (OR: 19.08, 95% confidence interval [CI]: 6.05-60.13) and ≥6 MRI signs was the cutoff point for massive bleeding (OR: 90.93, 95% CI: 11.3-729.23), hysterectomy (OR: 72.5, 95% CI: 17.9-293.7), or extensive bladder repair (OR: 58.74, 95% CI: 7.35-469.32). The MRI score was not significant for predicting adverse neonatal events including preterm delivery (P = 0.558), low birthweight (P = 0.097), and 5-minute Apgar score (P = 0.078).

DATA

CONCLUSION

Preoperative identification of specific MRI features may predict peripartum course in high-risk patients for PAS.

LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:602-618.