Diagnosing placenta accreta spectrum in different placental locations using a combination of magnetic resonance imaging (MRI) features and diffusion-weighted MRI parameters.

BACKGROUND

Placenta accreta spectrum (PAS) is usually difficult to diagnose in posterior placenta. This study aimed to determine whether certain magnetic resonance imaging (MRI) features and diffusion-weighted imaging (DWI) parameters could help diagnose PAS in different placental locations.

METHODS

We retrospectively enrolled 19 posterior PAS and 68 anterior PAS patients who had been diagnosed with PAS based on intraoperative findings and pathology. All the patients underwent DWI. DWI parameters calculated from different DWI models, and MRI features analyzed from conventional MRI images were compared. The discriminative ability of the DWI parameters and MRI features in diagnosing PAS in different placental locations were measured by receiver operating characteristic (ROC) curve and logistic regression analyses.

RESULTS

Diffusion coefficient (D) was selected from DWI to predict posterior PAS, and had a sensitivity of 84% and a specificity of 68%, while pseudo-diffusion coefficient (D*) was selected to predict anterior PAS, and had a sensitivity of 65% and a specificity of 86%. Of the MRI features, T2 dark bands and abnormal intraplacental vascularity were found to predict both anterior and posterior PAS. When the MRI features and DWI parameters were combined, the model had an area under the curve (AUC) of 0.903 [95% confidence interval (CI): 0.791-1], a sensitivity of 90%, and a specificity of 89% for posterior PAS, and an AUC of 0.858 (95% CI: 0.767-0.948), a sensitivity of 77%, and a specificity of 90.9% for anterior PAS.

CONCLUSIONS

D and D* were associated with posterior PAS and anterior PAS, respectively. A combination of morphological and functional markers may improve the diagnostic confidence of PAS in different placental locations.