MRI ANATOMY OF THE CRANIAL NERVES Alexandra Borges Radiology Dpt. Instituto Português de Oncologia de Lisboa SENR 2014
CRANIAL NERVES Olfactory: I Optic: II Oculomotor nerves: III, IV, VI Trigeminal nerve: (V1, V2, V3) Facial nerve (VII) Vestibulochoclear (VIII) Glossopharyngeal (IX) Vagus (X) Spinal accessory (XI) Hypoglossal nerve (XII)
CRANIAL NERVES: Anatomy Segments: Brainstem/ fascicular Cisternal (cavernous sinus CNs III, IV, VI) Skull base Exocranial 3DFT CISS Borges A, Casselman J. "Imaging the cranial nerves Part I. Eur Radiol 17(8):2112-2125, 2007
CNs MR IMAGING TECHNIQUE MR FSE T2W 3DFT-CISS SE T1W pre- and post gad 3DFT- MPRAGE TR 4000 12.25 684 11.6 TE 99 5.9 20 4.9 FA 180º 70º 90º 12º Acq. time 3 7.14 5.31 10.51 Thick 4 0.7 2 1 Matrix 242x512 192x256 160x256 192x256 FOV 300 95 230 240 Pixel size 0.62x0.59 0.49x0.37 0.90x0.90 0.94x0.94
FACIAL NERVE (CN VII) Brainstem segment (lower pons) Cisternal segment (CPA cistern) Temporal bone segment: Intracanalicular Labyrinthine Tympanic Mastoid Parotid segment
BRAINSTEM SEGMENT Axial TSE T2W 3T Mn Gn CN VIn Ln Axial CISS T2* 7T Courtesy from Prof. Francis Veillon Courtesy from Dr. Teresa Ferreira
TEMPORAL BONE AND PAROTID SEGMENTS From Ric Harnsberger Imaging anatomy
CN VII Facial nerve supplies: Motor fibers to: stapedius muscle, stylohyoid, occipitalis, posterior digastric, muscles of facial expression, buccinator and platysma PS fibers to lacrimal and salivary glands via the GPSN Taste fibers to 2 anterior thirds of the tongue via chorda tympani
VESTIBULO-COCLEAR NERVE
VESTIBULO-COCLEAR NERVE Bill s bar ANT. POST. Crista falciformis VII VIIIvs VIIIc VIIIvi Courtesy from Prof. Francis Veillon
VESTIBULO-COCLEAR NERVE Organ of Corti MIP CISS Scarpa ganglion Courtesy from Dr. Jan Casselman Spiral ganglion
LOWER CRANIAL NERVES (IX, X, XI) Spinal V Solitary Inf. salivatory Ambiguous
LOWER CRANIAL NERVES
JUGULAR FORAMEN EAC Petrous bone Carotid artery Jugular vein Inf. petrous sinus Jacobson nerve Meningeal branches Pars vascularis JF
CN IX (GLOSSOPHARYNGEAL NERVE) Provides: Motor fibers to the palatoparyngeus Sensory fibers to the pharyngeal plexus (CNX) Sensory fibers to middle ear and PS fibers to parotid gland (via tympanic branch or Jacobson s nerve) Taste fibers to the posterior third of the tongue (via lingual branch)
CN X (VAGUS NERVE) Longest course along the carotid space Contributes to pharyngeal plexus Gives off two major branches Superior laryngeal nerve Inferior or recurrent laryngeal nerve
CN X (VAGUS NERVE) Superior laryngeal branch Recurrent laryngeal branch
CN X (VAGUS NERVE) It also provides: Motor innervation to the pharyngeal muscles Visceral sensation from the larynx, trachea, esophagus, thoracic and abdominal viscera Sensory fibers to the external ear and tympanic membrane (via the auricular nerve or Arnold s nerve)
CN XI (SPINAL ACCESSORY NERVE
CN XII (HYPOGLOSSAL NERVE)
CN XII
CONCLUSIONS Major technical advances on MR hardware and software led to a dramatic increase on MR imaging resolution The intracranial course of CNs can now be nicely imaged: Detailed knowledge of CN anatomy Mastering MR technique Adequate tailoring of imaging to the diffent segments of the nerves Increase the diagnostic yield in patients presenting with CN deficits
Thank you very much for your attention!