Yoshiko Ueno, Presenter: Nothing to Disclose

Kazuhiro Kitajima MD, Abstract Co-Author: Nothing to Disclose

Tetsuo Maeda, Abstract Co-Author: Nothing to Disclose

Yuko Suenaga, Abstract Co-Author: Nothing to Disclose

Satoru Takahashi MD, Abstract Co-Author: Nothing to Disclose

Kazuro Sugimura MD, PhD, Abstract Co-Author: Research Grant, Toshiba Corporation Research Grant, Koninklijke Philips Electronics NV Research Grant, Bayer AG Research Grant, Eisai Co, Ltd Research Grant, DAIICHI SANKYO Group

To identify new MR criteria and review established MR criteria for the diagnosis of placental invasion.

A retrospective review of prenatal MR scans of 64 patients (mean age, 34years) who underwent MR examination for suspected placental invasion by prenatal sonogram was performed. All MRI examinations were performed on a 1.5-T unit with body array coils, including axial, coronal, and sagittal T2 half-Fourier single-shot turbo spin echo imaging and/or a T2 true fast imaging with steady-state precession sequence. According to surgical and/or pathological findings, 14 patients were diagnosed with placenta accreta, placenta increta, or placenta percreta, and 50 were without placental invasion. Two experienced radiologists who were blinded to the pathology and surgery findings reviewed the MRI and evaluated a total of eight MRI features of placenta, including our new finding; the presence of placental protrusion into internal os. Interrater reliability was assessed using kappa statistics. The features with a kappa statistics >0.40 were evaluated to compare the capabilities for placental invasion assessment with a multivariable logistic regression analysis.

Intraplacental T2 dark bands, Intraplacental abnormal vascularity, uterine bulging, total placental previa, partial placental previa and placental protrusion into internal os had moderate or better interobserver reliability. Using multivariable logistic regression analysis, we found that the findings of intraplacental abnormal vascularity (A) and placental protrusion into internal os (B) had significant odds ratios of an increased risk of placental invasion. (A: odds ratio, 82.7; 95% CI, 4.1 to 5942; p=0.002, B: odds ratio, 83.1; 95% CI, 3.61 to 6329; p=0.0047)

In this study, the findings of intraplacental abnormal vascularity and protrusion of placenta into the internal os were good predictors of placental invasion.

This study showed that the presence of placental protrusion into internal os is new useful MRI finding for the diagnosis of invasive placentation.

Ueno, Y, Kitajima, K, Maeda, T, Suenaga, Y, Takahashi, S, Sugimura, K, Brand-new MRI Finding as Predictor of Placental Invasion: Evaluation of 64 Patients with Clinical and Histopathological Correlation.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13018285.html