Request for a Ultrasound scan after a MRI

Hi, i’ve done a MRI from my neck a couple of weeks ago and now the imagine department have request a ultrasound of my neck. 

I tried to contact them, but i have no anwer and my MRI test results are not with my GP ether. 

I extremly concern: why they have resquest another imagine test? Did they see anything wrong? 

Thank you.

Fabiane.