Magnetic Resonance Imaging (MRI) is an adjunct to ultrasound in the assessment of placental adhesion disorder (PAD). Although various MRI features of PAD have been described (for example, placental heterogeneity, T2 dark intraplacental bands, abnormal placental vascularity, abnormal uterine bulge, etc.) their exact diagnostic utility remains uncertain, and their inclusion in both research and clinical radiology is inconsistent.1,2 The purpose of this study was to determine (a) the intraobserver agreement of MRI features of PAD, and (b) whether accuracy for the MRI diagnosis of PAD...

A retrospective analysis was performed. Expectant mothers undergoing prenatal MRI for suspected PAD were identified over a 10-year period, from 1 January 2007 to 31 December 2016. Patients were included in the analysis where their MRIs were reported by two participating radiologists (NY, SE). Both radiologists re-reviewed the MRIs images independently, blinded to the previous reports as well as the surgical and histological outcomes. Evaluation included the presence or absence of PAD, severity (accreta, increta, percreta) and various recognised MRI features of PAD. Intraobserver agreement...

Forty-one patients met inclusion criteria. Intraobserver agreement (see Fig. 1) was strong for the presence/absence of PAD (κ=0.74), severity (κ=0.81) and placental location (κ=0.90). However, intraobserver agreement was at best weak to moderate for the individual MRI features of PAD: placental heterogeneity (κ=0.18), T2 dark intraplacental bands (κ=0.53), abnormal placental vascularity (κ=0.15), abnormal uterine bulge (κ=0.59), myometrial thinning (κ=0.27), and organ invasion (κ=0.56). Five initial report conclusions failed to state the presence or absence of PAD. Regarding report accuracy, there was a slightly higher AUC...

Overall accuracy of MRI for the detection of PAD was high and did not significantly change over time. This was reinforced by the strong intraobserver agreement for the presence of PAD and grading PAD severity. However, there was poor intraobserver agreement for the individual MRI features of PAD, likely due to failure of description in the report rather than a true disagreement. This is of importance as such MRI features may help to predict patient outcomes and guide their perioperative and operative management.3

1. Cuthbert F, Teixidor Vinas M, Whitby E. The MRI features of placental adhesion disorder—a pictorial review. Br J Radiol [serial on the Internet] 2016 [cited 2018 Mar 18]; 89(1065). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5124928/ 2. Rahaim NSA, Whitby EH. The MRI features of placental adhesion disorder and their diagnostic significance: systematic review. Clinical Radiology. 2015 Sep;Volume 70(No 9): p917–25. 3. Kilcoyne A, Shenoy-Bhangle AS, Roberts DJ, Sisodia RC, Gervais DA, Lee SI. MRI of Placenta Accreta, Placenta Increta, and Placenta Percreta: Pearls and Pitfalls. American Journal...