FIG 7. 57-year-old man with right-sided trigeminal neuralgia.

A and B, Multisection 3-mm-thick 2D image (A) and 30-mm-slab 1-mm-section 3D image (B). A mass (white arrowheads) presumed to be an epidermoid cyst compressing the trigeminal nerve (black arrowheads) is depicted in the right cerebellopontine angle. Although the tumor is isointense with CSF on the 3D image (large arrow), the tumor can be recognized more clearly on the 2D image, owing to signal loss in CSF (small arrows).