Which modality is more accurate to confirm the diagnosis of semicircular canal aplasia?
High-resolution CT is preferred and more accurate than MRI. Absence (aplasia) of the semicircular canal(s) is distinguishable from fibrous obliteration with a normal appearance of the canal on CT and labyrinthitis ossificans with calcifications within the canal while they all have the same appearance in MRI.
Which modality is preferred for evaluating an enlarged vestibular aqueduct?
MRI is the preferred modality to identify the integrity of the cochlear nerve and the fluid-filled spaces of the inner ear. Axial T2-weighted is preferred for the assessment of vestibular aqueducts and sacs.
The patient was evaluated 6 years after for a new onset of atypical migraine and aura with MRI and MRA studies. No intracranial parenchymal, meningeal or vascular abnormality was identified.
Bilaterally dilated vestibular aqueducts are redemonstrated as T2 hyperintense structures in the posterior aspect of the temporal petrous pyramids and lateral to internal auditory canals. Left lower mastoid T2 hyperintensities correspond to left mastoid partial opacities in the CT, most likely serosal fluid accumulation.