CEREBELLO-PONTINE ANGLE (CPA) PROTOCOL
Intended to provide a detailed examination of the seventh and eight cranial nerves and the other C-P angle structures, especially for detecting acoustic neuromas. The fifth cranial nerve is included on imaging. General brain images are obtained to make the exam more comprehensive.
- ? acoustic neuroma
- ? CP angle lesion
- SN deafness
- Vertigo or Tinnitus
Sequences stored under Head/ CP_ANGLE
SCOUT Three plane low resolution scout
PD + T2 AXIAL Full brain coverage TSE axials. 5 mm thick with 50% gap
- Position slices parallel to the line joining the Genu and Splenium of the Corpus Callosum.
- Cover the brain from below the Foramen Magnum to the Vertex.
- Sat band just below inferior slice and parallel to the slice
CISS_Axial High resolution 3D bright fluid sequence to define the cochlea and semi-circular canals and outline the cranial nerves.
- Centre on the Acoustic nerves, angle to place scan plane roughly parallel to the roof of the 4th ventricle.
- Use MPR software to correct positional errors and display full length of the nerves.
Variations & Optional Sequences
- If the CISS images show an acoustic neuroma, or look suspicious do the isotropic MP-RAGE and make axial MPRs.
- For follow up of known acoustics, and lesions treated with radiosurgery just do post contrast isotropic MP-RAGE with axial and coronal reconstructions.