What is Fetal cisterna magna?

The cisterna magna (CM) [1] or cerebellomedullary cistern is a subarachnoid space that lies between the caudal aspect of the cerebellum and the medulla oblongata draining the fourth ventricle.

What malformations can be detected by fetal MRI?

In intracranial abnormalities, it is known that the common indication for taking fetal MRI includes ventriculomegaly, agenesis corpus callosum, Dandy-Walker malformation or variant, arachnoid cyst, and holoprosencephaly.

How accurately does current fetal imaging identify posterior fossa anomalies?

Fetal MRI Findings Of the 90 cases referred for suspected posterior fossa anomalies by fetal sonography, 25 (28%) were found to have normal posterior fossa structures by fetal MRI (Table 1) and five were found to have supratentorial ventriculomegaly only.

Does cisterna magna grow?

Enlargement of the cisterna magna has been reported to be associated with aneuploidy. In prior studies of cisterna magna enlargement, however, those fetuses with abnormal chromosomes have had other sonographic abnormalities in addition to a large cisterna magna.

What does the cisterna magna do?

The cisterna magna contains cerebrospinal fluid and is located behind the cerebellum in the posterior fossa of the brain. It communicates with the fourth ventricle via the foramina of Magendie and Luschka.

What are symptoms of prominent cisterna magna?

The majority of patients are asymptomatic; however, variable neurodevelopmental outcomes, including delayed speech and language development, motor development delay, visiospatial perception difficulties, and attention problems, has been observed in some patients.

What can fetal MRI detect better than ultrasound?

Fetal MRI allows us to evaluate the fetal brain with greater detail compared to ultrasound. As a result, fetal MRI can detect abnormalities in the fetal brain that are not visible on prenatal ultrasound.

Is Mega cisterna magna normal?

Mega cisterna magna refers to a normal variant characterised by a truly focal enlargement of the subarachnoid space in the inferior and posterior portions of the posterior fossa. It is an incidental finding on neuroimaging, and no imaging follow up is necessary.

Does the fetal cisterna magna appear on an antenatal sonogram?

The fetal cisterna magna. Antenatal sonography routinely images the fetal cisterna magna. The identification of a prominent cisterna magna on a routine antenatal sonogram performed for obstetric indications may raise the question of a congenital posterior fossa lesion.

Can antenatal sonography detect congenital posterior fossa lesion?

Antenatal sonography routinely images the fetal cisterna magna. The identification of a prominent cisterna magna on a routine antenatal sonogram performed for obstetric indications may raise the question of a congenital posterior fossa lesion.

What is the depth of the cisterna magna?

The cisterna magna depth measured 5 +/- 3 mm; the largest cisterna magna measured 10 mm in depth. In the absence of other findings to suggest a posterior fossa lesion, a prominent cisterna magna is unlikely to be clinically significant.

What does an MRI scan of the fetus show?

MRI depicts well fetal masses in the context of whole body of the fetus in multiple planes, which may be underestimated by US because of obscuration by bony structures or fetal position [3,4]. MRI is particularly useful in the assessment of pregnancies complicated by oligohydramnios which can limit the diagnostic sensitivity of US [1,3].