AJR: Ultrasound, MRI aid placenta accreta diagnosis

Leesburg, VA, May 27, 2021–According to an open-access Editor’s Choice article in ARRS’ American Journal of Roentgenology (AJR), accurate prenatal diagnosis of severe placental accreta spectrum (PAS) disorder by imaging could help guide maternal counseling and selection between hysterectomy and uterine-preserving surgery.

“The findings suggest strong performance of placental bulge in diagnosing severe PAS on both ultrasound and MRI, with potentially relatively stronger performance on MRI,” wrote corresponding author Manjiri Dighe from the department of radiology at the University of Washington School of Medicine. “Nonetheless, interobserver agreement remains suboptimal on both modalities.”

On ultrasound and MRI alike, the placental bulge sign represents deeper venous invasion in PAS–the focal area of myometrial-placental bulging beyond the normal uterine contour. Dighe and colleagues’ retrospective study included 62 pregnant women (mean age, 33.2 years) with clinically suspected PAS who underwent both ultrasound and MRI. Blinded to final diagnoses, two maternal-fetal medicine specialists for ultrasound and three abdominal radiologists for MRI independently reviewed images for their respective modality. Using intraoperative and pathologic findings, alongside International Federation of Gynaecology and Obstetrics classification, patients were separated into those with and without severe PAS.

“In diagnosing severe PAS,” Dighe et al. noted, “placental bulge sign achieved on ultrasound an accuracy of 85.5%, sensitivity of 91.7%, and specificity of 76.9%, and on MRI an accuracy of 90.3%, sensitivity of 94.4%, and specificity of 84.6%.” Ultimately, placental bulge was an independent predictor of severe PAS on ultrasound (odds ratio=8.94) and MRI (odds ratio=45.67).

“Placental bulge sign on either prenatal ultrasound or MRI may help diagnose severe PAS warranting hysterectomy rather than conservative management,” the authors of this AJR article concluded.

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Founded in 1900, the American Roentgen Ray Society (ARRS) is the first and oldest radiological society in North America, dedicated to the advancement of medicine through the profession of radiology and its allied sciences. An international forum for progress in medical imaging since the discovery of the x-ray, ARRS maintains its mission of improving health through a community committed to advancing knowledge and skills with an annual scientific meeting, monthly publication of the peer-reviewed American Journal of Roentgenology (AJR), quarterly issues of InPractice magazine, AJR Live Webinars and Podcasts, topical symposia, print and online educational materials, as well as awarding scholarships via The Roentgen Fund®.