Another look at ultrasound and magnetic resonance imaging for diagnosis of placenta accreta.
OBJECTIVE
To compare the ability of magnetic resonance imaging (MRI) and ultrasound (US) in the diagnosis of placenta accreta, to examine the success of various sonographic and MRI features to correctly predict invasive placenta, and to define a specific role for MRI in placenta accreta.


METHODS
After Institutional Review Board approval, a blinded retrospective review was undertaken of US and MRI findings from 45 patients who had an obstetrical US and placental MRI between August 2006 and January 2012. Correlation with clinical history and pathologic findings was performed.


RESULTS
US and MRI had similar sensitivity, specificity and positive and negative predictive values for placenta accreta. The best predictors of invasion by US were loss of the myometrial mantle, increased intraplacental vascularity and loss of the bladder wall echogenicity. The best predictors of invasion by MRI were loss of retroplacental myometrial mantle, a heterogeneous placenta, and intraplacental hemorrhage. Body mass index (BMI) did not affect the ability to make a diagnosis by either US or MRI. MRI proved effective in better evaluation of a posterior placenta with suspicion of placenta accreta. There was modality disagreement in 11 of 45 cases and MRI was correct in 9 of these 11 cases, all true negative (TN) cases.


CONCLUSIONS
MRI should be considered in any case with posterior placenta previa and suspicion of accreta, in any case with clinical suspicion for accreta and discordant US findings, and in any case in which percreta is suspected.
a Department of Radiology , Loyola University Medical Center , Maywood , IL , USA.
Nancy E
NE
Budorick
b Department of Obstetrics and Gynecology , Saint Francis Hospital and Medical Center, Quinnipiac University , Hartford , CT , USA.
Reinaldo
R
Figueroa
c Department of Obstetrics and Gynecology , Fountain Valley Regional Hospital and Medical Center , Fountain Valley , CA , USA , and.
Michael
M
Vizcarra
d Department of Radiology , Stony Brook University Health Sciences Center School of Medicine , Stony Brook , NY , USA.
James
J
Shin
D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010921:Placenta Accreta / Q000000981:diagnostic imaging*; D011247:Pregnancy; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D055815:Young Adult
Abnormal placentation; invasive placenta; obstetrical ultrasound; placental magnetic resonance imaging