The MRI features of placental adhesion disorder—a pictorial review

Abstract

Placental adhesion disorder (PAD) comprises placenta accreta, increta and percreta lesions; these are classified according to the depth of uterine invasion. Although PAD is considered a rare condition, its incidence has increased 10-fold in the last 50 years. Ultrasound is the primary imaging modality for the assessment of the placenta and in the majority of cases, it is sufficient for diagnosis; however, when ultrasound findings are suspicious or inconclusive, MRI is recommended as an adjunct imaging technique. Numerous MRI features of PAD have been described, including dark intraplacental bands, disorganized intraplacental vascularity and abnormal uterine bulging. This pictorial review describes and illustrates these characteristics and discusses their implications in planning delivery. In addition, we present a series of "pitfall" cases to aid the interpreting radiologist and discuss management of PAD. PAD is a clinical and diagnostic challenge that is encountered with increasing frequency, requiring a cohesive multidisciplinary approach to its management.

The haemodynamics of the human placenta in utero

“…Ultrasound is a very powerful technique for guiding care in clinical obstetrics; uterine artery Doppler can measure flow in larger vessels and can assess spiral artery resistance indirectly [8], but provides limited information on movement of blood within or across the IVS [9]. Magnetic Resonance Imaging (MRI -glossary in Table S1) is increasingly used to study fetal growth and development, and diffusion weighted imaging (DWI) of the AF F utero-placental unit is established as a clinical marker of placental adhesion [10] and DWI and T2 * -weighted imaging are increasingly being used to assess placental development [11][12][13][14][15][16][17][18][19][20].…”

The haemodynamics of the human placenta in utero

“…Ultrasound is a very powerful technique for guiding care in clinical obstetrics; uterine artery Doppler can measure flow in larger vessels and can assess spiral artery resistance indirectly [8] but provides limited information on movement of blood within or across the IVS [9]. Magnetic resonance imaging (MRI-glossary in S1 Table) is increasingly used to study fetal growth and development, diffusion-weighted imaging (DWI) of the utero-placental unit is established as a clinical marker of abnormally invasive placentation [10], and DWI and T 2 � -weighted imaging are increasingly being used to assess placental development [11][12][13][14][15][16][17][18][19][20].…”

Magnetic resonance imaging of the female pelvis after Cesarean section: a pictorial review

“…13). Prior Csection and placenta previa are the two most important risk factors for placental adhesion disorder (PAD), also called morbidly adherent placenta (MAP), which includes placenta accreta, increta, and percreta [26,27]. MAP can lead to placental retention, uncontrollable postpartum bleeding, postpartum infection, and hysterectomy although less definitive surgical intervention and/or uterine artery embolization is preferred, if possible [11].…”

“…Dynamic contrast-enhanced fat-saturated T1 sequence before (b) and after (c) gadolinium administration. Retained products of conception (RPOC) of mixed signal intensity in the C-section niche after treatment with potassium chloride and methotrexate (arrows) hemorrhage and DWI sequence-for invasion, in the best projection, most often sagittal [27,28]. The cardinal imaging findings of placenta accreta are T2hypointense intraplacental bands, heterogeneity of the placenta, and abnormal disorganized placental vascularity ( Fig.…”

“…Thinning or even loss of retroplacental T2 dark zone which may be a normal finding in the growing pregnancy or may be encountered in case of uterine dehiscence after previous C-section Blood clots mimicking dark intraplacental bands Bulges indenting the bladder that suggest invasion while they may represent bladder varices (Fig. 16) or focal bulge in the region of the maternal umbilicus which is a physiological finding caused by the separation of the rectus muscles in growing pregnancy [26,27] All the authors in the literature stress the necessity of complementary use of both US and MRI in these clinical situations [26][27][28][29].…”