What Do These Following Ultrasound Scan Reports Indicate?

Posted on Thu, 3 Nov 2016

Question: 29 year female, in 35 week of pregnancy.all previous scans lie NT,ANOMALY - completly XXXXXXX however in last scan done 3 last weeks has finding of dialated cysterna Magna ? cyst 23mm in posterior fossa.request you to kindly confirm are there any further complecations to baby.is it a sudden finding as all previous scans were normal.(report attached for reday reference)

Answered by Dr. Vivek Chail (1 hour later)

Brief Answer:
If previous scans were normal then it is an isolated and usually harmless finding

Detailed Answer:
Hi,
Thanks for writing in to us.

I have read through your query in detail.
Please find my observations below.

Cisterna magna is an opening in the base of the brain. The normal size of cisterna magna is 10 mm. If it is larger than 10 mm then it is reported as enlarged.

There have been many cases where there is no abnormal report in early and mid pregnancy and in the last 3 months, there might be an enlarged cisterna magna like in your case.

In this situation, it can be one of the following
1. An isolated enlarged cisterna magna with a possible arachnoid cyst
2. A posterior fossa cyst with other congenital problems.

Keeping in mind the reports of the scans done before, it is likely that your baby has an isolated cisterna magna with a possible arachnoid cyst and this condition usually will not cause any serious harm or complications.

However it is important to do an echocardiography after birth and to follow up with a neurologist and to do an ultrasound scan brain or MRI brain scan few days after birth as clinically required.

Hope your query is answered.
Please do write back if you have any doubts.

Regards,

Above answer was peer-reviewed by : Dr. Vaishalee Punj