Upload
beryl-randall
View
222
Download
1
Tags:
Embed Size (px)
Citation preview
EE 137: MR Imaging Review of the Skull Base Foramina
and Their Lesions
Brandon W. Sur MD, MSEDepartment of Imaging Sciences
University of Rochester Medical Center
Disclaimer
The author has no financial disclosure or
conflicts of interest with the presented
material in this presentation.
Objectives
Review anatomical location of the skull base
foramina with CT images
Review contents of each foramen
Learn various lesions affecting each foramen with
exemplary MR images.
Cribriform Plate
Contents Olfactory bulbs/nerves Anterior ethmoidal artery
(extradural)
Anatomy Thin, horizontal bony plate
with numerous foramina transmitting nerves
Part of the ethmoid bone Bounded laterally by the
lateral lamella
Cribriform Plate
Lesions Meningioma Esthesioneuroblastoma Squamous cell carcinoma Lymphoma Melanoma Olfactory schwannoma Bony lesions: fibrous dysplasia,
metastases
Esthesioneuroblastoma: Axial (A), coronal (B), and sagittal (C) T1+C images show a heterogeneously enhancing mass in the nasal cavity destroying the cribriform plate and extending intracranially
A
B
C
Cribriform Plate
Lesions Meningioma Esthesioneuroblastoma Squamous cell carcinoma Lymphoma Melanoma Olfactory schwannoma Bony lesions: fibrous dysplasia,
metastases
Olfactory groove meningioma: Sagittal (D), axial (E) , and coronal (F) T1+C images show an intensely enhancing dural based mass within the olfactory groove.
D E
F
Optic Canal
Contents Optic nerve and its
meninges Ophthalmic artery Central retinal vein Sympathetic nerve fibers
Anatomy Located in the posterior portion of the
orbital roof Situated within the base of the lesser
wing of the sphenoid bone
Optic Canal
Lesions Optic nerve glioma Meningioma Schwannoma Lymphomatous/leukemic
infiltration Hemangioblastoma Cavernous hemangioma Sarcoidosis
Optic Glioma: Axial T2 (A) shows diffusely thickened right optic nerve in a patient with neurofibromatosis type I. Axial T1+C (B) shows no significant enhancement.
A
B
Optic Canal
Lesions Optic nerve glioma Meningioma Schwannoma Lymphomatous/leukemic Hemangioblastoma Cavernous hemangioma Sarcoidosis
Optic nerve sheath meningioma: Coronal (C) and axial (D) T1+C images show enhancement along the left optic nerve and extending into the optic canal.
C
D
Superior Orbital Fissure
Contents Oculomotor nerve Trochlear nerve Abducens nerve Ophthalamic (V-1) nerve Ophthalmic veins Sympathetic nerve plexus Orbital branch of middle
meningeal artery Recurrent branch of
lacrimal artery
Anatomy Located between the
lesser and greater wings of the sphenoid bone
Pathway between the cavernous sinus and the apex of the orbit
Lesions
Aneurysm Meningioma Pituitary tumors Craniopharyngioma Perineural spread of
tumor Lymphoma Orbital varix
Inferior Orbital Fissure
Contents Maxillary nerve Zygomatic nerve Orbital branches of
pterygopalatine ganglion Infraorbital vessels;
inferior ophthalmic veins
Anatomy Located inferior to the
superior orbital fissure Bounded superiorly by the
greater wing of sphenoid, inferiorly by maxilla and orbital process of palatine bone, and laterally by the zygomatic bone.
Lesions Meningioma Schwannoma Perineural spread of
tumor
Foramen Rotundum
Contents Maxillary (V-2) nerve Artery of the foramen
rotundum Emissary veins
Anatomy Located at the anterior
base of the greater wing of the sphenoid bone
Runs laterally obliquely downward
Foramen Rotundum
Lesions Schwannoma Meningioma Nasopharyngeal
carcinoma Metastasis Perineural spread
Nasopharyngeal Carcinoma: Coronal (A) and axial (B) T1+C images show an ill-defined, enhancing sinonasal mass extending through the right foramen rotundum.
A B
Foramen Rotundum
Lesions Schwannoma Meningioma Nasopharyngeal carcinoma Metastasis Perineural spread
Skin Squamous Cell Carcinoma Metastasis: Coronal (C) and axial (D) T1+C images show enhancement along the left foramen rotundum.
C D
Foramen Ovale
Contents Mandibular (V-3) nerve Accessory meningeal
artery Emissary veins
Anatomy Located at the posterior base of the
greater wing of the sphenoid bone; posterolateral to the foramen rotundum
Extracranial opening at the lateral pterygoid plate
Foramen Ovale
Lesions Schwannoma Meningioma Neurofibroma Hemangiopericytoma Perineural spread of
tumor
Meningioma: Sagittal (A) and axial (B) T1+C images show a dural based enhancing mass extending through the right foramen ovale.
A B
Foramen Spinosum
Contents Meningeal branch of
mandibular (V-3) nerve Middle meningeal artery
Anatomy Situated in the greater
wing of the sphenoid bone Located posterolateral to
the foramen ovale
Lesions Perineural spread of
tumor Metastasis
Foramen Lacerum
Contents Greater petrosal nerve Internal carotid artery
overlies
Anatomy Situated in the occipital
bone Located between the
occipital condyle and jugular tubercle
Runs anterolaterally Lesions Perineural spread of
tumor Metastasis
Stylomastoid Foramen
Contents Facial nerve Styloidmastoid artery
Anatomy Located in the temporal bone Termination of the facial canal
Stylomastoid Foramen
Lesions Schwannoma Neurofibroma Perineural spread of tumor
Schwannoma: Axial (A) and coronal (B) T1+C images show enhancement along the facial canal and the stylomastoid foramen.
Adenoid cystic carcinoma: Coronal T1+C (C) image shows an enhancing right parotid gland mass extending intracranially through the stylomastoid foramen and destroying the temporal bone.
A
B
C
Internal Auditory Canal
Contents Facial nerve Vestibulocochlear nerves Labyrinthine arteryAnatomy
Located in the petrous part of the temporal bone
Runs laterally
Internal Auditory Canal
Lesions Schwannoma Meningioma Epidermoid Arachnoid cyst
Schwannoma: Axial (A) and coronal (B) T1+C images show a heterogeneous, enhancing mass in the left cerebellopontine angle involving the left internal auditory canal.
A B
Internal Auditory Canal
Lesions Schwannoma Meningioma Epidermoid Arachnoid cyst
Bilateral Acoustic Neuromas: Axial (C) and coronal (D) T1+C images of neurofibromatosis type II patient show bilateral enhancing masses in the bilateral internal auditory canals.
C
D
Jugular ForamenAnatomy
Formed by the petrous part of the temporal bone and the occipital bone
Two compartments divided by the jugular spine:smaller, anteromedial, “pars nervosa” and larger, posterolateral, “pars vascularis”
Contents Glossopharyngeal nerve Inferior petrosal sinus Vagus nerve Spinal accessory nerves Internal jugular vein Ascending pharyngeal& occipital
artery branches
Jugular Foramen
Lesions Schwannoma Meningioma Glomus tumor Metastases Perineural spread of tumor
Glomus Tumor: Coronal (A) and axial (B) T1+C images show a heterogeneous, enhancing mass within the left jugular foramen.
A B
Jugular Foramen
Lesions Schwannoma Meningioma Glomus tumor Metastases
Chondrosarcoma: Axial (C) and coronal (D) T2 images demonstrate a T2 hyperintense lesion in the left jugular foramen. Axial T1+C image (E) shows heterogeneous enhancement.
C
D
E
Hypoglossal Canal
Contents Hypoglossal nerve Meningeal branch of
ascending pharyngeal artery
Emissary vein
Anatomy Situated in the occipital
bone Located between the
occipital condyle and jugular tubercle
Runs anterolaterally
Hypoglossal Canal
Lesions
Meningioma Schwannoma Persistent hypoglossal
artery
A
B
Meningioma: Coronal T1+C (A) and axial T1+C (B) images show an enhancing, dural based mass occupying the foramen magnum and extending into the right hypoglossal canal.
Schwannoma: Coronal T1+C (C) and axial T1+C (D) images show a dumbell-shpaed (not fully seen in these two images), enhancing mass within the right hypoglossal canal.
C
D
Hypoglossal Canal
Lesions Meningioma Schwannoma Persistent hypoglossal artery
Persistent Hypoglossal Artery: Axial (E) and coronal (F) images of CT angiogram of the head show persistent hypoglossal artery within expanded left hypoglossal canal.
G
Dissection of Persistent Hypoglossal Artery: Axial image of CT angiogram of the head/neck (G) shows dissection of the persistent hypoglossal artery within the left hypoglossal canal.
E
F
Foramen Magnum
Contents Spinal cord; medulla
oblongata and meninges Vertebral arteries Spinal arteries and nerves
Anatomy Situated in the occipital
bone A line drawn between the
basion and opisthion defines the opening
Foramen Magnum
Lesions Meningioma Schwannoma Chordoma Neurofibroma
Meningioma
Coronal (A), sagittal (B) and axial T1+C (C) images show an intensely enhancing, dural based mass occupying the foramen magnum.
A
C
B
Schwannoma: Coronal T1+C (D) image of a patient with NF2 shows an enhancing mass within the foramen magnum extending down to the spinal canal.
D
Conclusion
Understanding of the anatomy of the skull base foramina,
knowledge of the characteristic and differential imaging
findings of disorders affecting them, and reviewing pertinent
clinical history will allow radiologists to formulate accurate
diagnoses and present appropriate differential diagnostic
considerations.
References Boulton MR, Cusimano MD. Foramen magnum meningiomas: concepts, classifications,
and nuances. Neurosurg Focus. 2006;14 (6): e10.
Fujita N, Shimada N, Takimoto H et-al. MR appearance of the persistent hypoglossal
artery. AJNR Am J Neuroradiol. 1995;16 (4): 990-2.
Snyder WE, Shah MV, Weisberger EC et-al. Presentation and patterns of late recurrence
of olfactory groove meningiomas. Skull Base Surg. 2011;10 (3): 131-9.
Vogl T, Brüning R, Schedel H et-al. Paragangliomas of the jugular bulb and carotid body:
MR imaging with short sequences and Gd-DTPA enhancement. AJR Am J Roentgenol.
1989;153 (3): 583-7.
Vogl TJ. Differential Diagnosis in Head and Neck Imaging. Thieme. 1999