Posterior Fossa Arachnoid Cyst (MR).,

PROTOCOL:
T2W – Sagittal & axial scans
T1W – Axial scans
FLAIR – Coronal scans
MR venography protocol

FINDINGS:

• An area of fluid accumulation is noted in the posterior fossa with indentation of the posterior wall of the skull. It measures about 32 x 31 mm in diameters; picture is suggestive of arachnoid cyst as it casts free diffusion on Diffusion images.
• Evidence of mega cisterna magna is noted.
• Few and tiny deep white matter abnormal signal intensity foci are noted (non specific).

-The rest of the brain Parenchyma shows normal grey white matter differentiation and signal intensities.  No focal mass lesion is seen.

-The superior sagittal sinus, straight sinus, bilateral transverse sinuses,  their confluence, bilateral sigmoid sinuses and parts of internal jugular vein visualized, show normal course, caliber and outlines. No obvious evidence of any venous sinus thrombosis is seen at present.

OPINION:

• Posterior fossa arachnoid cyst.


Reported By : DR.MOHAMMED MOHYELDIN
 Consultant-Radiologist