Imaging of the Placenta: A Multimodality Pictorial Review

Abstract

The placenta is often overlooked in the routine evaluation of a normal gestation, receiving attention only when an abnormality is detected. Although uncommon, abnormalities of the placenta are important to recognize owing to the potential for maternal and fetal morbidity and mortality. Pathologic conditions of the placenta include placental causes of hemorrhage, gestational trophoblastic disease, retained products of conception, nontrophoblastic placental tumors, metastases, and cystic lesions. Sonography remains the imaging modality of choice for evaluation of the placenta. Magnetic resonance (MR) imaging can be of added diagnostic value when further characterization is required, particularly in the setting of invasive placental processes such as placenta accreta and gestational trophoblastic disease. Computed tomography (CT) has a limited role in the evaluation of placental disease owing to limited tissue characterization, compared with that of MR imaging, and the radiation risk to the fetus; this risk often outweighs the benefit. The primary role for CT is in the evaluation of trauma and gestational trophoblastic disease, for which it allows characterization of the primary lesion and distant metastases.

Placental Thickness: Its Correlation with Ultrasonographic Gestational Age in Normal and Intrauterine Growth-Retarded Pregnancies in the Late Second and Third Trimester

“…The placenta develops from the chorionic villi at the implantation site at about the fifth week of gestation and by the ninth or tenth week, the diffuse granular echo texture of the placenta is clearly apparent at sonography [4,5]. Placental thickness appears to be a promising parameter for estimation of gestational age of the fetus because of increase in placental thickness with gestational age.…”

The morbidly adherent placenta: when and what association of signs can improve MRI diagnosis? Our experience

“…Our results suggest that MRI accuracy can further increase when specific signs are considered for the diagnosis. In addition, MRI examination is superior to US in soft tissue contrast and field of view (2) and can be useful in those cases where US can fail. MRI diagnosis of invasive placenta improves patient management at cesarean section, reducing both mother and fetus mortality and morbidity.…”

“…Our study protocol includes the supine decubitus with medium bladder distention to better assess potential bladder invasion and employment of multichannel surface coil, which maximizes the signal, providing a superior signal-to-noise ratio. Fast MRI sequences are usually suggested in the literature since they provide motion-free images of the abdomen in a limited time (2,13). Examination time usually takes about 30 minutes.…”

Ultrasonographic evaluation of acute pelvic pain in pregnant and postpartum period

“…Gestational trophoblastic disease encompasses a broad spectrum of conditions, includes a hydatidiform mole, invasive mole, choriocarcinoma, and placental site trophoblastic tumor [11,19]. US findings include heterogeneous echogenic endometrial mass with multiple variable-sized small anechoic cysts, giving the appearance of a "cluster of grapes" and increased vascularity with low resistance waveforms [19].…”

“…US findings include heterogeneous echogenic endometrial mass with multiple variable-sized small anechoic cysts, giving the appearance of a "cluster of grapes" and increased vascularity with low resistance waveforms [19].…”