Unilateral Hearing Loss

Vestibular schwannoma (aka acoustic schwannoma): Benign tumor from Schwann cells that wrap vestibular CN8 branches.

Typically small ovoid. (This is the largest internal auditory canal (IAC) schwannoma I have come across.)  Large chronic IAC schwannomas enlarge the IAC (trumpeting)

They avidly enhance.

If the patient presents with unilateral sensory hearing loss, what is the best imaging study to order?

MRI Brain IAC with and without contrast.

What is the Dx?

Vestibular schwannoma

http://radiopaedia.org/articles/acoustic-schwannoma

Different patient:  Confusion. When should you order MRI Brain with and without contrast?
To evaluate for confusion start with CT Head, then if indicated MRI Brain without contrast. Because of the blood brain barrier, contrast adds little information to an MRI brain.  It just makes it more expensive.

Reasons to use contrast:

1.      In a patient with cancer, looking for intracranial metastatic disease.

2.      A patient with known multiple sclerosis, some neurologist order contrast. Healing or actively demyelining lesions will enhance.