MRI of Pregnancy-Related Issues: Abnormal Placentation

Abstract

As abnormal placentation becomes more prevalent, in large part due to the markedly rising rates of cesarean delivery, there is a need for accurate antenatal diagnosis of this condition to prevent maternal morbidity and mortality. Maternal and fetal outcomes can be optimized through multidisciplinary planning to achieve accurate diagnosis and anticipation of the extent of abnormal placentation in the antenatal period. Imaging findings of abnormal placentation have been described for both ultrasound and MRI, although limitations exist for each technique. Although ultrasound remains the primary screening modality for the detection of abnormal placentation, MRI is a complementary technique that should be considered when ultrasound is inconclusive or incomplete. Familiarity with MRI techniques to assess the placenta, MRI appearance of normal placenta, and imaging findings that suggest abnormal placentation can help radiologists contribute to a successful maternal outcome.

The MRI features of placental adhesion disorder and their diagnostic significance: systematic review

“…Leyendecker and colleagues 2 agreed that these sequences reasonably differentiate between the placenta and myometrium, but available evidence suggests that it is difficult in practice. 2,33 Morita and co-workers 34 suggested that diffusionweighted (DW) sequences seems promising in evaluation of invasive placenta. 34 They reported that in DW images the placenta at a b-value of 1000 sec/mm 3 shows very high signal intensity, which enables clear identification of the placentaemyometrium interface.…”

“…Any focal bulging raises suspicion of invasion (Fig 4). 28,37 Leyendecker et al (2012) considered this imaging sign as the most useful criterion in isolation 2 ; however, this criterion is very specific but less sensitive as it exists only in the percreta cases. Furthermore, its diagnostic accuracy varied between studies as they were all small in size and the sensitivity depends on the number of percreta cases in each study.…”

“…1 The morbidity and mortality rate increases with the increase in the depth of invasion. 2,3 Although PAD is considered as a rare condition its incidence has increased 10 times in the last five decades. 4 Universally PAD is increasingly considered as a major cause of obstetric complications.…”

Ultrasound Imaging of Placenta Accreta With MR Correlation

“…9,30 Myometrial contractions consisting of transient, focal, ill-defined T2 hypointense thickening can also be seen. 31 The myometrium typically has a trilaminar appearance on T2-weighted or bSSFP images (Fig. 7A).…”

Morbidly Adherent Placenta: Ultrasound Assessment and Supplemental Role of Magnetic Resonance Imaging

“…Of greater significance is localized bulging of the placenta and considered by some to be the most important sign of placenta accreta. 32 The placenta has a smooth contour; localized bulging or disruption of its otherwise smooth contour is very suggestive of a morbidly adherent placenta. Focal interruption of the myometrium is another useful sign of placenta accreta (Fig.…”