ECNR_MdeWin_non-tumoral cranial nerves.pdfAmsterdam UMC, AMC
European Course in Neuroradiology, 15th Cycle Module 4
Degenerative, metabolic and inflammatory diseases
Nov 11 2020
LEARNING OBJECTIVES
• To chose the rigth imaging protocol for different cranial nerve
pathology
• Know different causes of non-tumoral CN pathology • Know how to
recognize and interprete CN pathology
IN TR
O D
UC TIO
TR O
D UC
TIO N
TR O
D UC
TIO N
[email protected]
12 CRANIAL NERVES Oh, Oh, Oh, To Touch And Feel Very Good Velvet,
Such A Heaven I. Olfactory nerve II. Optic nerve III. Occulomotor
nerve IV. Trochlear nerve V. Trigeminal nerve VI. Abducens nerve
VII. Facial nerve VIII. Vestibulocochlear nerve IX.
Glossopharyngeal nerve X. Vagus nerve XI. Accessory nerve XII.
Hypoglossal nerve
IN TR
O D
UC TIO
N
[email protected]
12 CRANIAL NERVES On, On, On, They Traveled And Found Volde mort
Guarding Very Ancient Horcruxes I. Olfactory nerve II. Optic nerve
III. Occulomotor nerve IV. Trochlear nerve V. Trigeminal nerve VI.
Abducens nerve VII. Facial nerve VIII. Vestibulocochlear nerve IX.
Glossopharyngeal nerve X. Vagus nerve XI. Accessory nerve XII.
Hypoglossal nerve
IN TR
O D
UC TIO
CRANIAL NERVES
• CN I & II: extensions of the brain, not ‘real’ nerves –
myelinated by oligodendrocytes, covered by meninges
• CN III t/m XII: ‘real’ nerves – myelinated by Schwann cells – 4
segments: intraaxial, cisternal, cranial/ skull base,
extracranial
IN TR
O D
UC TIO
Pathology divided according to the segments Important for imaging
protocol
Clinical information needed! Neurological examination
Central vs peripheral
TR O
D UC
TIO N
MRI protocol • Dedicated protocol
– ≠ standard brain protocol – Include brainstem & skull base –
N II, III, IV, VI include orbital imaging – N V include face (V1,
V2, V3) – N VII include CPA, temporal bone, parotid space – N VIII
include CPA, IAC and inner ear – N IX-XII include basal cisterns,
skull base, carotid space
• High resolution (2-3 mm max slice thickness)IN TR
O D
UC TIO
MRI protocol • Cisternal segments: 3D heavily T2-weighted series
(b-SSFP,
CISS, DRIVE, FIESTA) • Ax & coronal T1 SE • Ax & coronal T1
fatsat SE • Or isovoxel 3D T1 VIBE/eThrive /DIXON before and
after
ctr • Optic nerve: coronal STIR • Intracranial segment:
CT protocol • Bony lesions, mastoid/sinonasal infection
IN TR
O D
UC TIO
IN TR
O D
UC TIO
IN TR
O D
UC TIO
CN TRAUMA
• Most common olfactory nerve (CN I) > facial nerve (CN VII)
> oculomotor nerves (CNs III, IV, and VI)
• Rare for trigeminal nerve (V) and CN IX - XII • Higher incidence
with skull base fractures and severe TBI
• Direct nerve injury • Indirect injury via post- concussive injury
and edema • Partial recovery
Coello et al J Neurosurg 2010
TR A
UM A
OLFACTORY NERVE TRAUMA
• N-I Olfactory nerve most commonly affected anosmia • Prevalence
20% (9,5% mild TBI, 20% moderate TBI, 43% severe TBI) • Imaging:
#anterior skull base, contusion
Singh et al Brain Injury 2018
TR A
UM A
OLFACTORY NERVE TRAUMA
• Olfactory nerve most commonly affeced anosmia • Prevalence 20%
(9,5% mild TBI, 20% moderate TBI, 43% severe TBI) • Imaging:
#anterior skull base, contusion, atrophy (late)
Singh et al Brain Injury 2018
M46, persistent anosmia 18 months after neurotrauma
TR A
UM A
FACIAL NERVE TRAUMA
• 2nd most common cause of facial palsy • 75% delayed facial palsy
3–14 days after a traumatic injury
In case of facial palsy / mastoid fracture after trauma Make
mastoid reconstructions from brain/face CT Consider separate HR
mastoid CT Important not to miss patient can benefit from steroids
& decompression
TR A
UM A
[email protected]
TRAUMA
INTRODUCTION
NEURITIS
[email protected]
N EU
RI TIS
• Postinfectious – Bell palsy
• Demyelination – MS
• Iatrogen – Postradiation, post-surgery, toxins, drugs
N EU
RI TIS
– Disruption of blood-nerve barrier contrast leakage • T2
Hyperintens signal (nI & nII) • Thickening (more often in
neoplastic disease)
Check Single vs multiple cranial nerves Nerve thickening: focal vs
diffuse Additional findings (dura, meninges, venous thrombosis,
brain edema, bone marrow, etc)
N EU
RI TIS
• Anosmia/ hyposmia • Very common, esp > 75y • Mostly
conductive: allergic / infectious rhinosinusitis /medication •
Other causes (trauma, neurodegenerative)
• Sensineural anosmia ‘neuritis’ • Infection
– GPA
N-I OLFACTORY NEUROPATHY in COVID-19
• Anosmia/ hyposmia common in COVID-19 (acute onset) • MRI: normal
/hyperinse signal olfactory bulb in acute stage; atrophy in
later
stage
Chiu et al. “COVID-19-induced anosmia associated with olfactory
bulb atrophy.” Neuroradiology, 2020,
[email protected]
Swelling, T2 hyperintense, enhancement n II
F > M Pain, visual loss, loss of colour vision Self-limiting
Bilateral (30%) Intra-orbital segment (MS) STIR/ T2 IR/ DIR most
sensitive Optic nerve sheet can be involved
M, 45y, rapid loss of vision OS & colour vision
[email protected]
Inflammatory/autoimmune o MS, NMO, anti-MOG
encephalomyelitis,
idiopathic, sarcoidosis, ADEM, SLE Infectious o Viral (VZ, HZ HIV),
Lyme, toxoplasmosis
Dd: Optic perineuritis (IOI), sarcoidosis, ischemic
neuropathy
[email protected]
N EU
RI TIS
STAT Dx Similar MRI findings, different clinical history Burkitt
lymphoma
[email protected]
N III-IV-VI OPHTHALMOPLEGIA
• Paralysis of the eye muscles abnormal eye movement • Different
causes, including neuropathy n III, IV and /or VI
N EU
RI TIS
Bilateral mass orbital apex, SOF L: extension IOF, cavernous
sinus
T2 hypointens No diffusion restriction Enhancement
DDx granulomatous inflammation, IgG4, sarcoidosis
Improvement with prednison
NVII- FACIAL NERVE NEURITIS M (39y), peripheral facial nerve
palsy
Enhancement of the geniculate, tympanic and mastoidal segments, no
mass
Inflammatory / neuritis
N EU
RI TIS
[email protected]
IDIOPATHIC FACIAL PALSY • = Bell’s palsy • 2/3 of all peripheral
facial nerve palsy’s • Potential role for HSV-1 / varicella zoster
• Grading according to House-Brackmann
• Acute start of symptoms • 65-85% recovery without treatment
(weeks- 6 months) • Corticosteroids < 72h
Clinical diagnosis, no additional imaging or blood tests
NHG standaard perifere aangezichtsverlamming
Indication for imaging • Gradual progression of symptoms •
Recurrence • Medical history (i.e. trauma, cancer, parotid lesion,
recent ear infection) • Associated symptoms (diplopia, dysphagia,
dizziness) • < 15yrs • No improvement of symptoms after
monthsN
EU RI
Indication for imaging • Gradual progression of symptoms •
Recurrence • Medical history (i.e. trauma, cancer, parotid lesion,
recent ear infection) • Associated symptoms (diplopia, dysphagia,
dizziness) • < 15yrs • No improvement of symptoms after
monthsN
EU RI
[email protected]
MULTIPLE CRANIAL NERVE ENHANCEMENT
• M 64, psychiatric history • Multiple cranial nerve palsy after
ethylene glycol intoxication (anti-freeze)
N EU
RI TIS
nIII
nV
nVII
Spillane et al Ann Emerg Med 1991; Moore et al Rad Case Rep
2008
[email protected]
[email protected]
• Physiological enhancement (nVII) • Neoplastic
– Benign (schwannoma’s) – CSF seeding – Perineural tumor spread
(ACC) – Infiltration by lymphoma, leukemia, multiple myeloma
Schwannoma nVII Perineural tumorspread nV
[email protected]
TRAUMA
INTRODUCTION
NEURITIS
VASCULAR
[email protected]
V A
SC UL
A R
• Microvascular cranial nerve palsy – ↓ blood supply to cranial
nerves – Hypertensia, diabetes – Not a radiological diagnosis
V A
SC UL
A R
• Growing aneurysm nerve compression • Pcom aneurysm nIII
palsy
– Down and out – Ptosis – Unreactive pupil, parasympathetic
pupillary fibers are
located peripherally in nerve
[email protected]
PCOM ANEURYSM & CN III PALSY • M, 50y, acute headache, diplopia
(nIII), ptosis OS • MRI: pCom aneurysm • Growing! Instable!
Indication for treatment!
V A
SC UL
A R
C N
V A
SC UL
A R
• M, 50y, acute headache, diplopia (nIII), ptosis OS • MRI: pCom
aneurysm • Growing! Instable! Indication for treatment!
[email protected]
CAVERNOUS SINUS THROMBOSIS • Post ctr T1 • Infection (venous
plexus) • Staphylococcus aureus 70% • nVI first involved
– Nasal deviation of the eye (esotropie) • Later nIII, IV, V1,
V2
C N
V A
SC UL
A R
NEUROVASCULAR COMPRESSION • Vascular contact/ compression at the
transition(TZ) or REZ • Myelin oligodendrocytes Schwann cells (TZ)
• Position of transition zone depends on the nerve
– TZ nV is at about 4 mm from BS, 1 mm length – TZ nVIII is at
about 10mm from BS, 1mm length
• Correlation with hypertension
NVC SYNDROMES • nV trigeminal neuralgia
– SCA > AICA – recurrent episodes of stabbing pain in the
territory of V1 or V2, triggered by
mild stimulation
• nVII hemifacial spasm – AICA > PICA > VA > vein –
Involuntary unilateral contractions of the muscles innervated by
the ipsilateral
facial nerve
• nIX Glossopharyngeal neuralgia – PICA > AICA – Neuralgia
posterior tongue, tonsil, throat, or external ear canal, can
be
triggered by eating, swallowing, and speaking
C N
V A
SC UL
A R
IMAGING in NVC
Aim: to exclude other pathology and to identify cause of NVC &
guiding treatment
MRI protocol Dedicated protocol • HR heavily T2-weighted series
(DRIVE, FIESTA, CISS,
SPACE) • MRA (3D TOF) • 3D T1(FS) after contrast (tumor, neuritis,
veins, pre-op) • MergeC
N V
A SC
UL A
[email protected]
IMAGING in NVC
Criteria on MRI • Perpendicular contact between CN & artery •
At the level of the transition zone • Visualised in 2 planes •
Distortion / stretching of the nerve • Distortion of the brain
stem
But… NVC not visualised in all patients with neuralgia / hemifacial
spasm NVC in 30% of asymptomatic persons!
C N
V A
SC UL
A R
IMAGING in NVC
• Always look for alternative! • M, 74y, sever pain with swallowing
• Referred for neurovascular decompression glossopharyngeal nerve
R
C N
V A
SC UL
A R
C N
V A
SC UL
A R
VASCULAR nIII pCOM aneurysm infection & ofthalmoplegia
cavernous sinus NVC TZ & frequently found in asymptomatic
persons
NEURITIS look for nerve enhancement aspecific, broad DDx clinical
information & medical history essential!
LEARNING POINTS
[email protected]
