MRI features of placenta accreta

Objective To investigate the MRI features of placenta accreta.Methods From Apr 2009 to Jun 2011,15 patients with placenta accrete received MRI examination.In them,placenta accrcta was diagnosed based on clinical manifestations or postoperative histopathologv.The MR features of placenta accreta in thcm( study group) were retrospectively analyzed and compared with those in 15 pregnant women without placenta accreta (control group)with Fisher exact test.Results In the 15 patients with placenta accreta,uterine bulging and(or) a focal outward contour bulge was detected in 14 patients; heterogeneous signal intensity in the placenta was detected in 15 patients; dark intraplacental bands on T2-weighted images was detected in 15 patients; and increased subplacental vascularity was detected in 11 patients on T1- weighted images.In the study group,14 patients showed at least three of the above four features,and in all of them uterine bulging and(or) a focal outward contour bulge,heterogeneous signal intensity in the placenta and dark intraplacental bands on T2-weighted images were detected; one patient showed heterogeneous signal intensity in the placenta,dark intraplacental bands on T2-weighted images and increased subplacental vascularity.In the control group,none patient had three of the above features.Uterine bulging and(or) a focal outward contour bulge,heterogeneous signal intensity in the placenta,dark intraplacental bands on T2-weighted images and increased subplacental vascularity were detected in 3,6,3 and 4 patients (P=0.000,0.001,0.000 and 0.027 ),respectively.Conclusions The main MRI features of placenta accreta are uterine bulging and(or) a focal outward contour bulge,heterogeneous signal intensity in the placenta and dark intraplacental bands on T2-weighted images Besides,increased subplacental vascularity also could provide useful information for the diagnosis of placenta accreta. Key words: Placenta, increta;  Magnetic resonance imaging;  Diagnostic imaging