Magnetic resonance image findings of placental lake: report of two cases

Structured evaluation and reporting in imaging of placenta and umbilical cord

The human placenta plays a pivotal role in development and growth of the fetus. Disorder of this multifunctional organ is central to various fetal disorders. Doppler sonography and MRI provide excellent diagnostic evaluation of the placental morphology and umbilical cord. Decades of experience in obstetric imaging have highlighted the need of careful prenatal assessment of placenta. However, in most of the routine obstetric scans, the evaluation and reporting of the placental examination is limited to the location and grade of the placenta. The purpose of this article is to review the existing literature and facilitate step-by-step evaluation of the placenta and umbilical cord by the radiologists.

Extrafetal Findings on Fetal Magnetic Resonance Imaging: A Pictorial Essay

Although US is the mainstay of fetal imaging, magnetic resonance imaging (MRI) has become an invaluable adjunct in recent years. MRI offers superb soft tissue contrast that allows for detailed evaluation of fetal organs, particularly the brain, which enhances understanding of disease severity. MRI can yield results that are similar to or even better than those of US, particularly in cases of marked oligohydramnios, maternal obesity, or adverse fetal positioning. Incidentally detected extrafetal MRI findings are not uncommon and may affect clinical care. Physicians interpreting fetal MRI studies should be aware of findings occurring outside the fetus, including those structures important for the pregnancy. A systematic approach is necessary in the reading of such studies. This helps to ensure that important findings are not missed, appropriate clinical management is implemented, and unnecessary follow-up examinations are avoided. In this pictorial essay, the most common extrafetal abnormalities are described and illustrated.

The clinical significance of large placental lakes

OBJECTIVE

The aim of our study was to establish whether there is a correlation between the size of placental lakes and adverse pregnancy outcome.

STUDY DESIGN

Target ultrasonography for diagnosis of placental lake was performed in the 2nd trimester of pregnancy and followed up in the 3rd trimester. Placental lakes were defined as homogenous sonolucent avillous lesions greater than 2 cm × 2 cm in diameter. The 109 pregnant women enrolled in this study were divided into four groups according to the size and change in size of placental lakes. Clinical characteristics and pregnancy outcomes in each group were compared.

RESULTS

Some placental lakes decreased and disappeared, whereas others persisted. There were no significant differences in clinical characteristics among the four investigated groups. Fetal small-for-gestational-age status was significantly correlated with large placental lakes, compared to small.

CONCLUSION

Large placental lakes were correlated with the fetal status of small for gestational age. Therefore, if a large placental lake is identified in the 2nd trimester of pregnancy, appropriate surveillance should be considered for the remainder of the pregnancy.