High-Resolution Isotropic Three-Dimensional MR Imaging of the Extraforaminal Segments of the Cranial Nerves

https://doi.org/10.1016/j.mric.2017.08.007Get rights and content

Section snippets

Key points

  • High-resolution isotropic 3-dimensional (D) MR imaging with and without contrast is now routinely used for imaging evaluation of cranial nerve anatomy and pathologic abnormality.

  • Previous work has highlighted the utility of sequences, including constructive interference in steady-state without and with intravenous contrast, in such cases.

  • The extraforaminal segments are well-visualized on these techniques, especially in the setting of contrast against varying tissue types.

  • The extraforaminal

Imaging approaches

At the authors’ institution, high-resolution isotropic 3D MR imaging protocol consists of the following sequences: precontrast and postcontrast 3D constructive interference in steady-state (CISS), 3D T2-weighted short-tau inversion recovery (STIR) SPACE (Sampling Perfection with Application optimized Contrasts using different flip angle Evolution), precontrast volumetric interpolated breath-hold examination (VIBE), and postcontrast VIBE with fat saturation (Table 1).4 In addition, standard

Technique (constructive interference in steady-state)

CISS sequence is a high-spatial resolution, refocused gradient echo sequence that can be obtained with isotropic resolution in a clinically acceptable acquisition time. Images can be reconstructed in any plane. CISS images have the appearance of T2-weighted images, although increased signal is easily recognized after administration of gadolinium-based contrast material in tissues that show contrast enhancement on T1-weighted images. Precontrast and postcontrast CISS sequences can be performed

Discussion

CN dysfunction can occur as a result of pathologic abnormality at any point along the nerve fibers, including the extraforaminal segments. The wide range of pathologic entities affecting CN#.a to CN #.f has been discussed elsewhere.1, 2, 3 This article highlights pathologic abnormality localized to the extraforaminal segment, with characteristic examples featured along with the discussion of normal CN anatomy.

Several entities may affect CNs in a similar manner, leading to the corresponding CN

Cranial nerve II: optic nerve, anatomy

The optic nerve is unique in that it is an extension of the central nerve system and not a CN by strict definition. It is surrounded entirely by meninges rather than Schwann cells, therefore all segments are considered intradural (segmentation of CN II has been discussed elsewhere), and the extraforaminal portion is located within the orbit after passage through the optic canal. CSF fluid and the optic sheath surround the optic nerve, separating it from the adjacent orbital fat (Fig. 3).

Cranial nerve III.g: oculomotor nerve, anatomy

The oculomotor nerve enters the orbital apex via the superior orbital fissure. It then branches into superior and inferior divisions. The superior division supplies the superior rectus muscle and levator palpebrae, whereas the inferior division innervates the medial and inferior rectus muscles (Fig. 5), as well as supplying parasympathetic innervation to the ciliary ganglia responsible for the pupillary reflex.2, 12

Cranial nerve IV.g: trochlear nerve, anatomy

CN IV.g exits the skull in the superolateral portion of the superior orbital fissure, external to the annulus of Zinn, along with the frontal and lacrimal branches of the ophthalmic division of CN V.1.g,12 eventually innervating the superior oblique muscle.

Cranial nerve VI.g: abducens nerve, anatomy

CN VI.f travels through the central portion of the superior orbital fissure along with the CN III.f to enter into the orbit and innervates the lateral rectus muscle.12

Cranial nerves III.g, IV.g, and VI.g: selected pathologic abnormalities

A wide range of causes of ocular CN palsies exist, including diabetic neuropathy, trauma, demyelinating disorders, congenital abnormality or absence,13 and idiopathic disease.14, 15, 16 Pathologic abnormalities that involve the ocular motor CNs can present with classic symptoms localizing to a specific CN palsy. However, given the close proximity of these nerves within the orbital apex, pathologic abnormalities involving 1 nerve may also masquerade as palsy of another.2 Symptoms such as

Cranial nerve V: trigeminal nerve

The trigeminal nerve is the largest of the CNs, with 3 main divisions supplying sensation to different regions of the face, as well as motor innervation to the muscles of mastication via the third division (CN V.3). The extraforaminal segment of each division and their associated pathologic abnormalities are discussed individually.

Cranial nerve VII.g: facial nerve, anatomy

The facial nerve is composed of a complex combination of motor, sensory, and parasympathetic fibers. The main extraforaminal trunk exits the temporal bone at the stylomastoid foramen along the posterior belly of the digastric muscle, and then immediately into the parotid gland.53 Just proximal to the parotid gland, the facial nerve gives off the posterior auricular nerve and branches to the posterior belly of the digastric and stylohyoid muscles.3 Within the parotid gland, the facial nerve

Cranial nerve VIII

CN VIII alone does not extend beyond the skull and, for this reason, does not formally have an extraforaminal segment, rather it passes through foramina to innervate the inner ear within the temporal bone.

Cranial nerves IX to XI

Due to the close anatomic location of the extraforaminal segments of CNs IX to XI, they are discussed here together, with particular emphasis on the vagus nerve.

Cranial nerve XII:g: selected pathologic abnormality

CN XII.g can be affected anywhere along its course to produce classic symptoms of CN XII palsy, tongue weakness on protrusion, with particular pathologic abnormalities having a predilection for particular segments of the nerve. Given the location of CN XII.g, it has an extensive course in the head and neck, and it can be involved in malignant processes originating from any of these spaces, including SCC; salivary gland tumors; such as adenoid cystic carcinoma63, 65; and lymphoma, which may

Summary

This article describes the normal high-resolution anatomy and appearance of several featured CNs, with specific emphasis on the extraforaminal portions. The superior visibility of many distal extraforaminal branches of these CNs on CISS sequences allows for assessment of involvement of these distal branches by pathologic assessment. The high signal-to-noise ratio, along with high spatial resolution with isotropic 3D images that can be reconstructed in multiple planes, makes this sequence

First page preview

First page preview
Click to open first page preview

References (70)

  • N.S. Chaudhry et al.

    Pineal region schwannoma arising from the trochlear nerve

    J Clin Neurosci

    (2016)
  • V.I. Elmalem et al.

    Clinical course and prognosis of trochlear nerve schwannomas

    Ophthalmology

    (2009)
  • M. Feichtinger et al.

    Intraorbital Schwannoma of the abducens nerve: case report

    J Oral Maxillofac Surg

    (2013)
  • D. Badger et al.

    Imaging of perineural spread in head and neck cancer

    Radiol Clin North Am

    (2017)
  • A. Eneh et al.

    Pediatric adenoid cystic carcinoma of the lacrimal gland treated with intra-arterial cytoreductive chemotherapy

    J AAPOS

    (2015)
  • F.M. Singh et al.

    Patterns of spread of head and neck adenoid cystic carcinoma

    Clin Radiol

    (2015)
  • A.T. Shah et al.

    Squamous cell carcinoma presenting with trigeminal anesthesia: an uncommon presentation of head & neck cancer with unknown primary

    Am J Otolaryngol

    (2017)
  • J. Gadde et al.

    Inflammatory pseudotumor of the nasopharynx with spread along the trigeminal nerve

    Am J Otolaryngol

    (2013)
  • P. Raghavan et al.

    Imaging of the facial nerve

    Neuroimaging Clin N Am

    (2009)
  • P. Alves

    Imaging the hypoglossal nerve

    Eur J Radiol

    (2010)
  • H.E. Wee et al.

    Diagnostic pitfall: adenoid cystic carcinoma of the tongue presenting as an isolated hypoglossal nerve palsy, case report and literature review

    Int J Surg Case Rep

    (2016)
  • M. Gursoy et al.

    Hypoglossal canal invasion by glomus jugulare tumors: clinico-radiological correlation

    Clin Imaging

    (2014)
  • G. Illuminati et al.

    Schwannoma of the descending loop of the hypoglossal nerve: Case report

    Int J Surg Case Rep

    (2017)
  • Y. Shigematsu et al.

    Contrast-enhanced CISS MRI of vestibular schwannomas: phantom and clinical studies

    J Comput Assist Tomogr

    (1999)
  • G.B. Chavhan et al.

    Steady-state MR imaging sequences: physics, classification, and clinical applications

    Radiographics

    (2008)
  • Z. Zhang et al.

    3-T imaging of the cranial nerves using three-dimensional reversed FISP with diffusion-weighted MR sequence

    J Magn Reson Imaging

    (2008)
  • Y. Qin et al.

    3D double-echo steady-state with water excitation MR imaging of the intraparotid facial nerve at 1.5T: a pilot study

    AJNR Am J Neuroradiol

    (2011)
  • A.H. Aiken et al.

    MR imaging of optic neuropathy with extended echo-train acquisition fluid-attenuated inversion recovery

    AJNR Am J Neuroradiol

    (2011)
  • J.M. Pollock et al.

    Neurosarcoidosis mimicking a malignant optic glioma

    J Neuroophthalmol

    (2008)
  • W.S. Millar et al.

    MR of malignant optic glioma of adulthood

    AJNR Am J Neuroradiol

    (1995)
  • J.M. Engel

    Treatment and diagnosis of congenital fourth nerve palsies: an update

    Curr Opin Ophthalmol

    (2015)
  • H.-C. Kau et al.

    High-resolution magnetic resonance imaging of the extraocular muscles and nerves demonstrates various etiologies of third nerve palsy

    Am J Ophthalmol

    (2007)
  • M.A. Tamhankar et al.

    Management of acute cranial nerve 3, 4 and 6 palsies: role of neuroimaging

    Curr Opin Ophthalmol

    (2015)
  • N.H. Kung et al.

    Isolated ocular motor nerve palsies

    Semin Neurol

    (2015)
  • N.A. Wani et al.

    Tolosa-hunt syndrome demonstrated by constructive interference steady state magnetic resonance imaging

    J Ophthalmic Vis Res

    (2017)
  • Cited by (12)

    • Magnetic resonance neurography in the management of trigeminal neuralgia: a cohort study of 55 patients

      2021, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
      Citation Excerpt :

      The neural abnormality produced a fairly bright signal or nerve thickening on 3D-CUBE fs images (Figure 3) compared with 2-dimensional images. The reconstructions of the long axis of the nerve showed signal or caliber alterations on the affected branches of the nerve, which is helpful for clinicians in preoperative treatment planning.20 Compared with the studies of Terumitsu et al.,14,15 we not only used 3.0-T MRI for imaging but also adopted more scanning sequences and applied more comprehensive image reconstruction methods.

    • Advanced Magnetic Resonance Imaging of the Skull Base

      2021, Seminars in Ultrasound, CT and MRI
      Citation Excerpt :

      MR cisternography sequences provide exquisite delineation of the anterior, central, and posterior skull base; cerebrospinal fluid and meninges; and complex neurovascular foramina for transit of cranial nerves, arteries, and veins. The various segments of the cranial nerves include that can be distinguished include nuclear, parenchymal fascicular, cisternal, dural cave, interdural, foraminal, and extraforaminal.10-15 These high-resolution sequences can also be used to delineate the anatomy of arachnoid cysts and adhesions, aqueductal stenosis and webs, and meningoceles.16-21

    View all citing articles on Scopus

    Disclosure: Dr A. Blitz has been on the medical advisory board for Guerbet. He is also partially funded by R21 NS096497 and FAIN U01DC013778 grants.

    View full text