Neuroradiology Flashcards
Cerebral cavernous malformations are most commonly associated with which of the following?
Answers:
A. Developmental venous anomaly
B. Intracranial aneurysm
C. Dural arteriovenous fistula
D. Capillary telangiectasia
E. Early draining vein
Developmental venous anomaly
Discussion:
Cerebral cavernous malformations (also revered to as cavernomas or cavernous hemangiomas)
are one of the most common intracranial vascular malformations with an estimated prevalence of
0.4-0.8% and account for 10-25% of all intracranial vascular malformations. Most cavernous
malformations are asymptomatic and found incidentally. The annual risk of hemorrhage is 1-3%,
with the most common presenting symptom being seizure. Radiographically, cavernous
malformations have a “popcorn-like” appearance on MRI with a rim of hemosiderin that is evident
on susceptibility weighted imaging (SWI), and they are frequently associated with developmental
venous anomalies (DVA). Angiographically, cavernous malformations are occult lesions; however,
an associated DVA will appear as a collection of dilated veins converging on an enlarged cortical
vein (“Caput medusae”) that fill in phase with the remainder of the venous system.
Cavernous malformations are not associated with a higher incidence of intracranial aneurysms,
dural AV fistulas, or capillary telangiectasias.
As DVAs fill in phase with the remainder of the venous system, there are no early draining veins.
This is in contrast to cerebral arteriovenous malformations and dural AV fistulas.
Figure 1. MRI, T1 weighted image with contrast demonstrating a DVA
*Image obtained with permission via Creative Commons Attribution 3.0 (Original source:
https://commons.wikimedia.org
/wiki/File:Developmental_Venous_Anomaly_MRT_T1KM_axial_04.jpg)
References:
Reference (1)
Awad IA, Polster SP. Cavernous angiomas: deconstructing a neurosurgical disease. J Neurosurg.
2019 Jul 1;131(1):1-13. doi: 10.3171/2019.3.JNS181724. PMID: 31261134; PMCID: PMC6778695.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/31261134/
Reference (2)
Harrigan MR, Devakis JP. Handbook of Cerebrovascular Disease and Neurointerventional
Technique. 2nd Ed. New York, NY: Springer-Verlag New York, LLC; 2012.
Reference (3)
Abdulrauf SI, Kaynar MY, Awad IA. A comparison of the clinical profile of cavernous malformations
with and without associated venous malformations. Neurosurgery. 1999 Jan;44(1):41-6; discussion
46-7. doi: 10.1097/00006123-199901000-00020. PMID: 9894962.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/9894962
The lesion indicated by the arrowheads on the gadolinium-enhanced T1 (left) and T2 (right) MR images is most likely a(n)
Answers:
A. Mega cisterna magna
B. Epidermoid cyst
C. Neuroenteric cyst
D. Dermoid cyst
E. Trigeminal schwannoma
Epidermoid cyst
Discussion:
The MRI image demonstrates an epidermoid cyst, which is an extra-axial cystic lesion that is
hyperintense on T2-weighted imaging, hypointense on T1-weighted imaging, and without
significant contrast enhancement. Notably, the lesion results in mass-effect on the brainstem.
Although not pictured, epidermoid cysts demonstrate diffusion restriction (bright) on diffusion
weighted imaging (DWI), which differentiates them from arachnoid cysts.
Mega cisterna magna is an anatomic variant in which the CSF space in the posterior and inferior
aspect of the posterior fossa is enlarged. The location of the lesion indicated by the arrow is not
consistent with a mega cisterna magna.
Dermoid cysts are developmental abnormalities lined with stratified squamous epithelium as well
as epidermal appendages (e.g. hair follicles, sweat glands). As opposed to epidermoid cysts,
dermoid cysts tend to occur along the midline. Radiographically, on MRI dermoid cysts tend to be
hyperintense on T1-weighted images without contrast enhancement and have a variable signal on
T2-weighted images.
Trigeminal schwannomas are rare nerve sheath tumors involving the trigeminal nerve (CN V).
Radiographically, they appear as a mass lesion on MRI that are isointense on T1-weighted images
with prominent enhancement and are hyperintense on T2-weighted images.
Neuroenteric cysts are rare benign congenital lesions more common in the spine than the
intracranial space. Radiographically, neuroenteric cysts tend to be hyperintense on T1- and T2-
weighted imaging.
References:
Reference (1)
Osborn AG, Preece MT. Intracranial cysts: radiologic-pathologic correlation and imaging approach.
Radiology. 2006 Jun;239(3):650-64. doi: 10.1148/radiol.2393050823. PMID: 16714456.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/16714456/
Reference (2)
Taillibert S, Le Rhun E, Chamberlain MC. Intracranial cystic lesions: a review. Curr Neurol
Neurosci Rep. 2014 Sep;14(9):481. doi: 10.1007/s11910-014-0481-5. PMID: 25106500.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/25106500/
A 25-year-old woman is evaluated for a transient episode of left-sided weakness. Posterioranterior and lateral angiograms obtained from a right common carotid injection are shown. Based on these findings, which of the following is the most likely diagnosis?
Answers:
A. dural arteriovenous fistula (AVF)
B. Moyamoya Disease
C. arteriovenous malformation
D. thromboembolic occlusion of the right internal carotid artery (ICA)
E. cavernous carotid fistula
Moyamoya Disease
Discussion:
This angiogram demonstrates occlusion of the terminal ICA and its proximal branches and
development of a basal collateral network. Suzuki (1965) first described this entity as Moyamoya
Disease because the appearance of these collateral channels resembled “something hazy like a
puff of cigarette smoke drifting in the air.”
Note that there is no evidence of early venous drainage to suggest arteriovenous malformation,
cavernous carotid fistula, or dural AVF. Occlusion of the ICA terminus by an embolus would not
show filling of this hypertrophied vascular network.
References:
Suzuki J, Takaku A. Cerebrovascular “Moyamoya” Disease: Disease Showing Abnormal Net-Like
Vessels in Base of Brain. Arch Neurol. 1969;20(3):288–299.
doi:10.1001/archneur.1969.00480090076012
Fujimura M, Bang OY, Kim JS. Moyamoya Disease. Front Neurol Neurosci. 2016;40:204-220. doi:
10.1159/000448314. Epub 2016 Dec 2. PMID: 27960175
Patients with herpes simplex, type 1 encephalitis typically show abnormalities on FLAIR imaging involving the temporal lobe, insula, and which of the following regions?
Answers:
A. Occipital lobe
B. Cerebellar hemispheres
C. Midbrain
D. Parietal lobe
E. Frontal lobe
Frontal lobe
Discussion:
Herpes simplex virus encephalitis (HSVE) has an incidence of 1-4/1 million cases annually. In the
United States, HSV can be attributed to 50-75% of sporadic encephalitis cases, and 90% of these
are caused by HSV-1. Mortality for treated HSVE is about 20% in 6 months. Clinical confirmation
includes PCR testing of CSF. In a study of 40 patients with HSVE who had an MRI, 95% of
patients demonstrated FLAIR/T2 changes with the majority of patients demonstrating radiographic
findings in the temporal lobe (87%) and insula (70%). In addition, 67.5% of patients had
radiographic changes in the frontal lobe.
References:
Singh TD, Fugate JE, Hocker S, Wijdicks EFM, Aksamit AJ Jr, Rabinstein AA. Predictors of
outcome in HSV encephalitis. J Neurol. 2016 Feb;263(2):277-289. doi:
10.1007/s00415-015-7960-8. Epub 2015 Nov 14. PMID: 26568560.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/26568560
Tyler KL. Acute Viral Encephalitis. N Engl J Med. 2018 Aug 9;379(6):557-566. doi:
10.1056/NEJMra1708714. PMID: 30089069.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/30089069
Jayaraman K, Rangasami R, Chandrasekharan A. Magnetic Resonance Imaging Findings in Viral
Encephalitis: A Pictorial Essay. J Neurosci Rural Pract. 2018 Oct-Dec;9(4):556-560. doi:
10.4103/jnrp.jnrp_120_18. PMID: 30271050; PMCID: PMC6126294.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/30271050/
The most likely cause of the findings in the CT scan shown is injury or occlusion of which of the following cerebral blood vessels?
Answers:
A. Recurrent artery of Heubner
B. Medial posterior choroidal artery
C. Anterior cerebral artery
D. Lateral lenticulostriate arteries
E. Anterior choroidal artery
Recurrent artery of Heubner
Discussion:
The CT image depicts a hypodensity that includes the head of the caudate nucleus and the
anterior limb of the internal capsule, which is the classic appearance for a recurrent artery of
Heubner infarct. The recurrent artery of Heubner is the largest lenticulostriate artery arising from
the anterior cerebral artery, most commonly arising from the proximal A2 segment. It supplies
several structures, including the head of the caudate nucleus, medial globus pallidus, anterior limb
of the internal capsule, and the anterior hypothalamus. A recurrent artery of Heubner stroke
classically presents as dysarthria and contralateral weakness of the arm and face. Clinically this is
important, as it is a commonly described complication after microvascular clipping of anterior
communicating artery aneurysms.
The anterior choroidal artery arises from the distal internal carotid artery and supplies the posterior
limb of the internal capsule, lateral thalamus, optic tract, lateral cerebral peduncle, globus pallidus
internus, and tail of the caudate. Anterior choroidal artery infarcts are a commonly described
complication after microvascular clipping of posterior communicating artery aneurysms and
present with contralateral hemiparesis, hemianesthesia, and hemianopia.
The medial posterior choroidal artery arises from the P2 segment of the posterior cerebral artery
and supplies the tegmentum, midbrain, posterior thalamus, and pineal gland, and typically
presents with abnormal eye movements and diplopia.
The anterior cerebral artery (ACA) arises as one of the two terminal branches of the internal
carotid artery. The ACA has several branches that supply frontal lobe and medial cerebral
hemisphere. ACA strokes typically present with predominant contralateral lower extremity
weakness and sensory changes.
The lateral lenticulostriate arteries arise from the horizontal segment of the middle cerebral artery
and supply the lateral putamen and external capsule, and present with contralateral hemiparesis
with largely preserved sensation.
References:
Reference (1)
Munakomi S, M Das J. Neuroanatomy, Recurrent Artery of Heubner. 2021 Sep 3. In: StatPearls
[Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 31424806.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/31424806/
Reference (2)
Osborn AG. Diagnostic Neuroradiology. St. Louis: Mosby; 1994: 133-134.
On the lateral view internal carotid artery angiogram shown, the arrow is pointing to which of the following arteries?
Answers:
A. Inferior parietal artery
B. Callosomarginal
C. Internal frontal
D. Frontopolar
E. Pericallossal
Pericallossal
Discussion:
The anterior cerebral artery distal to the anterior communicating artery is referred to as the
pericallosal artery (arrow). The frontopolar artery and the inferior parietal arteries are typically
branches of the pericallossal artery. The callosomarginal artery is a branch of the pericallossal
artery. It runs parallel to the pericallossal artery in the sulcus above the cingulate gyrus
(Perlemutter 1978). Approximately 15% of the time it is absent. When it is present, it supplies the
internal frontal and paracentral arteries. Note that there is considerable variability of the ACA
branching pattern between individual patients.
References:
Perlmutter D, Rhoton AL Jr. Microsurgical anatomy of the distal anterior cerebral artery. J
Neurosurg. 1978 Aug;49(2):204-28. doi: 10.3171/jns.1978.49.2.0204. PMID: 671075.
Cilliers K, Page BJ. Review of the Anatomy of the Distal Anterior Cerebral Artery and Its
Anomalies. Turk Neurosurg. 2016;26(5):653-61. doi: 10.5137/1019-5149.JTN.14294-15.1. PMID:
27337235
During diagnostic cerebral angiography, while navigating the great vessels of the arch, the operator finds that the diagnostic catheter repeatedly falls into the left subclavian artery when a move from the brachiocephalic to the left common carotid artery (LCCA) is attempted. The most likely explanation for this is which of the following?
Answers:
A. aberrant subclavian artery origin
B. situs invertus
C. arch is bovine
D. LCCA origin occlusion
E. subclavian steal
arch is bovine
Discussion:
There are typically (3) vessels exiting the aortic arch: brachiocephalic, left common carotid, and left
subclavian artery. In about 15% of cases the left common carotid artery does not come directly off
the arch but rather comes off as a branch of the brachiocephalic artery. This is often called a
bovine aortic arch. When this is the case, pulling the catheter out of the brachiocephalic artery into
the arch in the usual fashion will result in catheterization of the left subclavian artery rather than
the left common carotid artery. Of note, it has been pointed out that this common nomenclature is
a misnomer. The typical arch configuration in cows is comprised of a single brachiocephalic trunk
giving rise to all of the cerebral vessels (Layton 2006).
References:
Layton KF, Kallmes DF, Cloft HJ, Lindell EP, Cox VS. Bovine aortic arch variant in humans:
clarification of a common misnomer. AJNR Am J Neuroradiol. 2006 Aug;27(7):1541-2. PMID:
16908576; PMCID: PMC7977516.
Lazaridis N, Piagkou M, Loukas M, Piperaki ET, Totlis T, Noussios G, Natsis K. A systematic
classification of the vertebral artery variable origin: clinical and surgical implications. Surg Radiol
Anat. 2018 Jul;40(7):779-797. doi: 10.1007/s00276-018-1987-3. Epub 2018 Feb 19. PMID:
29459992
An 11-year-old boy is evaluated for left-sided lower extremity weakness and paresthesias. A vascular lesion is noted at the T10 spinal level. Which of the following vessels is indicated by the arrows in the spinal angiogram shown?
Answers:
A. Artery of Adamkiewicz
B. anterior spinal artery
C. posterior radiculomedullary artery
D. posterior spinal artery
E. anterior radiculomedullary artery
anterior spinal artery
Discussion:
The correct answer is the anterior spinal artery. In this angiogram of a spinal arteriovenous
malformation (AVM), the proximal portion of the anterior spinal artery (black arrows) is normal, but
the descending loop is enlarged because it is feeding the AVM. In the thoracic spine, the anterior
spinal artery receives contributory flow from multiple anterior radiculomedullary arteries, the largest
of which is called the Artery of Adamkiewicz. It makes a classic “hairpin loop” upon entry to the
anterior spinal artery. There are generally no communication or anastomoses between the anterior
and posterior spinal arteries, thus making the artery of Adamkiewicz similar to an end artery. This
vascular anatomy can often lead to anterior spinal cord syndrome within the region of the lumbar
spinal cord, leading to loss of motor function and sensory function carried by the anterior columns
including pain and temperature (sparing proprioception within the dorsal column, which is supplied
by the posterior spinal artery). The posterior spinal arteries are more lateral relative to the spinal
cord.
References:
Yoshioka K, Niinuma H, Ehara S, Nakajima T, Nakamura M, Kawazoe K. MR angiography and CT
angiography of the artery of Adamkiewicz: state of the art. Radiographics. 2006 Oct;26 Suppl
1:S63-73. doi: 10.1148/rg.26si065506. PMID: 17050520.
Gofur EM, Singh P. Anatomy, Back, Vertebral Canal Blood Supply. [Updated 2021 Jul 26]. In:
StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from:
https://www.ncbi.nlm.nih.gov/books/NBK541083
Which of the following helps reduce the radiation exposure to operating personnel during surgery?
Answers:
A. Attempt to bring the image intensifier as far away from the patient and the x-ray source as close to the patient as possible
B. Wear proper lead or lead-equivalent shielding at all times during fluoroscopy
C. Attempt to use rapid continuous fluoroscopy over spaced out pulsed fluoroscopy
D. Attempt to limit use of collimation whenever possible
E. Attempt to stand on the side of the patient with the x-ray source instead of the image intensifier
Wear proper lead or lead-equivalent shielding at all times during fluoroscopy
Discussion:
When utilizing intra-operative radiation, it is imperative that all unnecessary personnel leave the
room while fluoroscopy is performed. Personnel who must remain in the operating room should
wear proper lead or lead-equivalent shielding at all times during fluoroscopy. It is also important to
know that the distance from the radiation source has an inverse-squared relationship to the
radiation dose. It has been shown that a distance 2-3 feet from the x-ray source will reduce total
radiation exposure by 8 times.
It is preferred to use pulsed fluoroscopy over continuous fluoroscopy to decreased total radiation
exposure.
Collimation of the x-ray source will decrease the radiation dose to the patient as well as reduce the
scatter experienced by the operating room team, and therefore should be used whenever possible.
X-ray scatter is greater on the side of the x-ray source compared to the side of the image
intensifier; therefore, it is preferable to stand on the side of the patient with the image intensifier.
Positioning a C-arm with the image intensifier as close to the patient as possible will decrease the
radiation scatter experienced by the surgeon.
References:
Reference (1)
Srinivasan D, Than KD, Wang AC, La Marca F, Wang PI, Schermerhorn TC, Park P. Radiation
safety and spine surgery: systematic review of exposure limits and methods to minimize radiation
exposure. World Neurosurg. 2014 Dec;82(6):1337-43. doi: 10.1016/j.wneu.2014.07.041. Epub
2014 Aug 1. PMID: 25088230.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/25088230/
Reference (2)
Kim HJ, Park ES, Lee SH, Park CH, Chung SW. Reduction of Radiation Exposure by Modifying
Imaging Manner and Fluoroscopic Settings during Percutaneous Pedicle Screw Insertion. J
Korean Neurosurg Soc. 2021 Nov;64(6):933-943. doi: 10.3340/jkns.2020.0338. Epub 2021 Aug
24. PMID: 34420290; PMCID: PMC8590905.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/34420290/
In the patient whose CT scan (A) and angiogram (B) are shown, the most likely cause of hemorrhage is rupture of a(n)
Answers:
A. Dural Arteriovenous Fistula
B. Spinal arteriovenous malformation
C. Posterior Inferior Cerebellar Artery (PICA) aneurysm
D. Venous varix
E. Cerebellar arteriovenous malformation (AVM)
Posterior Inferior Cerebellar Artery (PICA) aneurysm
Discussion:
This vertebral angiogram demonstrates an aneurysm in the telovelotonsillar segment of PICA.
Distally, the PICA feeds a small cerebellar arteriovenous malformation (AVM). The CT shows
hemorrhage in the 4th ventricle and inferior vermis. There is also a fair amount of subarachnoid
hemorrhage (SAH). The telovelotonsillar segment of PICA is in close proximity to the 4th ventricle
and inferior vermis, and this pattern of hemorrhage is typical of distal PICA aneurysms. Bleeding
from the AVM would have been more localized to the cerebellar parenchyma and would not likely
have caused so much subarachnoid or intraventricular blood. A detailed review of this anatomy
was published by Hudgins and Rhoton (1983).
References:
Hudgins RJ, Day AL, Quisling RG, Rhoton AL Jr, Sypert GW, Garcia-Bengochea F. Aneurysms of
the posterior inferior cerebellar artery. A clinical and anatomical analysis. J Neurosurg. 1983
Mar;58(3):381-7. doi: 10.3171/jns.1983.58.3.0381. PMID: 6827323.
Orakcioglu B, Schuknecht B, Otani N, Khan N, Imhof HG, Yonekawa Y. Distal posterior inferior
cerebellar artery aneurysms: clinical characteristics and surgical management. Acta Neurochir
(Wien). 2005 Nov;147(11):1131-9; discussion 1139. doi: 10.1007/s00701-005-0599-y. Epub 2005
Aug 1. PMID: 16052289
Based on the radiograph of the spine shown, which of the following is the most likely diagnosis?
Answers:
A. Ankylosing spondylitis
B. Diffuse idiopathic skeletal hyperostosis
C. Rheumatoid arthritis
D. Spondylolysis
E. Degenerative spondylosis
Diffuse idiopathic skeletal hyperostosis
Discussion:
The lateral lumbar radiograph demonstrates diffuse idiopathic skeletal hyperostosis (DISH). DISH
has three diagnostic criteria:
1. “Flowing” ossification of at least four contiguous vertebral levels, most commonly involving
the anterior longitudinal ligament
2. Relative preservation of disk height and lack of significant degenerative changes
3. The absence of key features of ankylosing spondylitis, including ankylosis posteriorly at the
facet joint interface (“bamboo spine”) and sacroiliac joint erosion
Ankylosing spondylitis (AS) is a seronegative spondyloarthropathy that may appear similar to
DISH. However, AS is strongly associated with HLA-B27 and tends to present in younger patients.
Radiographically, AS tends not to have the “flowing” pattern of ossification and includes ankylosis
of the posterior spinal elements (Figure 1.)
Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory arthropathy, classically affecting
the fingers and hands. When RA involves the spine, it typical results in erosion of the dens and
development of atlantoaxial instability.
Spondylolysis is defined as a defect in the pars interarticularis, which is not demonstrated in the
radiograph.
While patients with DISH may also develop degenerative spondylosis, the classic degenerative
findings of loss of disk space height, osteophyte formation, and endplate sclerosis are not seen in
DISH.
*Image used with permission via CC BY-SA 4.0 (Original source: https://commons.wikimedia.org
/wiki/File:AnkSponTLateral2016.png)
References:
Reference (1)
Luo TD, Varacallo M. Diffuse Idiopathic Skeletal Hyperostosis. 2021 Aug 23. In: StatPearls
[Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 30855792.
Pubmed Web link
https://www.ncbi.nlm.nih.gov/books/NBK538204/
Reference (2)
Mario Cammisa, Antonio De Serio, Giuseppe Guglielmi. Diffuse idiopathic skeletal hyperostosis.
European Journal of Radiology. Volume 27, Supplement 1, 1998, Pages S7-S11. ISSN 0720-048X,
https://doi.org/10.1016/S0720-048X(98)00036-9.
Reference (3)
Mader R, Baraliakos X, Eshed I, et al. Imaging of diffuse idiopathic skeletal hyperostosis (DISH).
RMD Open 2020;6:e001151. doi: 10.1136/rmdopen-2019-001151
A 22-year-old woman is brought to the emergency department 90 minutes after a high-speed rollover motor vehicle collision. Physical examination shows proptosis and erythema of the left eye. Lateral (Figure A) and anteroposterior (Figure B) angiograms of the left internal carotid artery are
shown. Which of the following structures is indicated by the arrows in the angiograms?
Answers:
A. pterygoid plexus
B. cavernous sinus
C. superior ophthalmic artery
D. inferior ophthalmic vein
E. contrast extravasation
pterygoid plexus
Discussion:
The angiogram shows a left cavernous carotid fistula (CCF). Venous drainage is predominantly
anterior through a dilated superior ophthalmic vein and the pterygoid plexus (arrow). The
pterygoid plexus (via the maxillary vein) can be used as a route to the cavernous sinus for
transvenous embolization of a CCF if the inferior petrosal sinus cannot be accessed (Chun, 2002).
References:
Chun GF, Tomsick TA. Transvenous embolization of a direct carotid cavernous fistula through the
pterygoid plexus. AJNR Am J Neuroradiol. 2002 Aug;23(7):1156-9. PMID: 12169474; PMCID:
PMC8185731.
Gemmete JJ, Ansari SA, Gandhi DM. Endovascular techniques for treatment of carotid-cavernous
fistula. J Neuroophthalmol. 2009 Mar;29(1):62-71. doi: 10.1097/WNO.0b013e3181989fc0. PMID:
19458580.
A male newborn is evaluated because of the lesion shown in the MR images and angiograms. Which of the following additional findings is most likely in this patient?
Answers:
A. Enlarged straight sinus
B. High output cardiac failure
C. Enlarged Vein of Galen
D. Slit ventricles
E. agenesis of choroidal arteries
High output cardiac failure
Discussion:
The MRI and angiogram demonstrate a Vein of Galen Malformation (VOGM) and associated
hydrocephalus in a neonate. The VOGM is a high flow arteriovenous shunt between the choroidal
arteries and the embryonic precursor to the Vein of Galen, the Median Porencephalic Vein of
Markowski (MPVM). Therefore, VOGM is a actually a misnomer. In neonates, the VOGM causes
so much arterial shunting that it often leads to high output cardiac failure. Other common
associated findings include hypertrophy of the choroidal vessels, hydrocephalus, and dilated scalp
veins. Note that it will often appear that the straight sinus is dilated, but drainage from the MPVM
to the torcula is via an abnormally enlarged falcine sinus. The true sagittal sinus is typically small
or even absent (Gailloud 2005).
References:
Gailloud P, O’Riordan DP, Burger I, Levrier O, Jallo G, Tamargo RJ, Murphy KJ, Lehmann CU.
Diagnosis and management of vein of galen aneurysmal malformations. J Perinatol. 2005
Aug;25(8):542-51. doi: 10.1038/sj.jp.7211349. PMID: 16015373.
Hoang S, Choudhri O, Edwards M, Guzman R. Vein of Galen malformation. Neurosurg Focus.
2009 Nov;27(5):E8. doi: 10.3171/2009.8.FOCUS09168. PMID: 19877798
The unenhanced (left) and gadolinium-enhanced (right) T1-weighted MR images shown are most consistent with a diagnosis of
Answers:
A. Epidermoid cyst
B. Abscess
C. Schwannoma
D. Arachnoid cyst
E. Hemorrhage
Epidermoid cyst
Discussion:
Intracranial epidermoids are epithelial cell tumors that commonly occur in the cerebellopontine
angle, where they can compress the brainstem and cranial nerves. They appear as lobulated
lesions that fill and expand CSF spaces and often encase adjacent nerves and
vessels. Epidermoids are often indistinguishable from CSF signal (such as in arachnoid cysts,
though these typically have smooth borders) on many MRI sequences, except that they commonly
restrict diffusion. Schwannomas and abscesses most frequently enhance with contrast, and the
appearance of hemorrhage varies based on time course but can be identified acutely on
susceptibility-weighted images.
Epidermoid cysts are extra-axial lesions commonly found in the posterior fossa, with the
cerebellopontine angle cistern being the most common location. On imaging, they classically
demonstrate hypodensity on CT scan, hypointensity on T1WI, and hyperintensity on T2-weighted
images (T2WI), almost similar to cerebrospinal fluid (CSF), with characteristic diffusion restriction
on diffusion-weighted imaging (DWI).
References:
Jamjoom, D.Z., Alamer, A. & Tampieri, D. Correlation of radiological features of white epidermoid
cysts with histopathological findings. Sci Rep 12, 2314 (2022).
Gao, P. Y., Osborn, A. G., Smirniotopoulos, J. G. & Harris, C. P. Radiologic-pathologic correlation.
Epidermoid tumor of the cerebellopontine angle. AJNR Am. J. Neuroradiol. 13, 863–872 (1992)
A 40-year-old man is evaluated for fever, rash, headache, stiff neck, and lethargy two weeks after a camping trip. A lumbar puncture and CSF Western blot analysis confirm Lyme disease. On neurological examination, a cranial neuropathy is noted. The most likely cranial nerve palsy caused by this infection is which of the following?
Answers:
A. CN IV
B. CN V
C. CN VI
D. CN VII
E. CN III
CN VII
Discussion:
Lyme disease, also known as borreliosis, is a disease acquired through infection by Borrelia
burgdorferi spirochetes with an incidence of about 30K cases/year in the United States. Clinically,
patients first present with the typical erythema migrans rash with antibodies developing over the
next 8 weeks. Neurologic symptoms related to Lyme disease may include Bannwarth’s syndrome,
often demonstrating a triad of radiculitis, peripheral motor deficits, and lymphocytic CSF. In less
than 5% of cases, patients may develop vasculitis, myelitis, or encephalitis. The most common
cranial neuropathy is a facial nerve palsy (>90% of cases), often occurring bilaterally, and is the
most common deficit in pediatric cases. Oculomotor nerve palsies and abducens nerve palsies
may also occur, however they occur in only 5% of cases.
References:
Ross Russell AL, Dryden MS, Pinto AA, Lovett JK. Lyme disease: diagnosis and management.
Pract Neurol. 2018 Dec;18(6):455-464. doi: 10.1136/practneurol-2018-001998. Epub 2018 Oct 3.
PMID: 30282764.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/30282764
Lindland ES, Solheim AM, Dareez MN, Eikeland R, Ljøstad U, Mygland Å, Reiso H, Lorentzen ÅR,
Harbo HF, Beyer MK. Enhancement of cranial nerves in Lyme neuroborreliosis: incidence and
correlation with clinical symptoms and prognosis. Neuroradiology. 2022 May 24. doi:
10.1007/s00234-022-02957-2. Epub ahead of print. PMID: 35608630.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/35608630
Which of the following MR scanning sequences will most effectively distinguish between abscess and tumor?
Answers:
A. T1
B. DWI/ADC
C. T1 + contrast
D. GRE
E. T2
DWI/ADC
Discussion:
A cerebral abscess is an infected pocket in the brain, typically with bacteria or fungus. It can be
difficult to diagnosis on imaging when comparing the lesion to a tumor. Both abscesses and
malignant brain tumors typically demonstrate a rim-enhancing pattern. Intracranial abscesses
frequently restrict diffusion, whereas contrast-enhancing malignant neoplasms rarely do. T1- and
T2-weighted sequences vary with both entities, and there is rarely GRE blooming artifact in the
absence of hemorrhage or calcification in either.
Multimodal MRI improves the differential diagnosis between brain abscesses and tumors, as the
capsule of pyogenic abscess appears hyperintense in T1-weighted sequence and hypointense in
T2-weighted sequence, with regular enhancement after gadolinium injection. The necrotic center
of pyogenic abscess is hypointense in T1-weighted sequence, hyperintense in T2-weighted
sequence, and typically hyperintense in diffusion weighted imaging (DWI) with restricted apparent
diffusion coefficient (ADC).
References:
Osborn AG. Diagnostic Neuroradiology
Feraco P, Donner D, Gagliardo C, Leonardi I, Piccinini S, Del Poggio A, Franciosi R, Petralia B,
van den Hauwe L. Cerebral abscesses imaging: A practical approach. J Popul Ther Clin
Pharmacol. 2020 Jul 11;27(3):e11-e24. doi: 10.15586/jptcp.v27i3.688. PMID: 32757543.
Carmine Franco Muccio, Ferdinando Caranci, Felice D’Arco, Alfonso Cerase, Luca De Lipsis,
Gennaro Esposito, Enrico Tedeschi, Cosma Andreula. Magnetic resonance features of pyogenic
brain abscesses and differential diagnosis using morphological and functional imaging studies: A
pictorial essay. Journal of Neuroradiology, Volume 41, Issue 3, 2014, Pages 153-167, ISSN
0150-9861
A 65-year-old woman has had generalized seizures and episodes of confusion and memory loss over the past ten weeks. On examination, the patient is alert but has profound short-term memory loss; neurologic function is otherwise intact. A T1-weighted MR image shows no contrast
enhancement. A T2-weighted MR image shows brightness within the mesial temporal lobes bilaterally. Which of the following is the most likely diagnosis?
Answers:
A. Coccidiodomycosis
B. Paraneoplastic limbic encephalitis
C. Abscess
D. Low-grade glioma
E. Mesial temporal sclerosis
Paraneoplastic limbic encephalitis
Discussion:
Paraneoplastic limbic encephalitis (PLE) is a rare neurological syndrome associated with cancer
and selectively affects limbic system structures, including the hippocampus, hypothalamus, and
amygdala. Imaging most frequently manifests with cortical thickening and increased T2/FLAIR
signal intensity of these regions. Mesial temporal sclerosis and low-grade glioma, although both T2
intense pathologies, are most commonly unilateral. Mesial temporal sclerosis is a vital etiology
underlying some forms of epilepsy. Multi-focal infections typically contrast enhance and are rarely
symmetric.
A study conducted by Gultekin et al in 2000 proposed the first diagnostic criteria for paraneoplastic
limbic encephalitis, which included the following: 1) short-term memory loss, seizures, or
psychiatric symptoms; 2) <4 years between symptom onset and cancer diagnosis; 3) exclusion of
metastases, infection, metabolic, or other causes; and 4) one of the following: inflammatory CSF
findings, temporal lobe T2 or FLAIR hyperintensity on MR imaging, or electroencephalogram
abnormality in the temporal lobes. Tüzün and Dalmau subsequently modified these criteria in 2007
to account for the growing subset of nonparaneoplastic forms of autoimmune encephalitis, which
also demonstrated prominent limbic involvement.
References:
Shen, K., Xu, Y., Guan, H. et al. Paraneoplastic limbic encephalitis associated with lung cancer. Sci
Rep 8, 6792 (2018).
Gultekin SH, Rosenfeld MR, Voltz R, et al. Paraneoplastic limbic encephalitis: neurological
symptoms, immunological findings and tumor association in 50 patients. Brain 2000;123(pt
7):1481–94 doi:10.1093/brain/123.7.1481 pmid:10869059
üzün E, Dalmau J.Limbic encephalitis and variants: classification, diagnosis and treatment. Neurologist 2007;13:261–71 doi:10.1097/NRL.0b013e31813e34a5 pmid:17848866
Which of the following structures is indicated by the arrow in the angiogram shown?
Answers:
A. ophthalmic artery
B. ethmoidal artery
C. superior ophthalmic vein
D. cavernous sinus
E. facial vein
superior ophthalmic vein
Discussion:
The common carotid artery angiogram shows a patient with a cavernous carotid fistula draining
anteriorly through a pathologically dilated superior ophthalmic vein (arrow) and, distally, the
anterior facial vein (Debrun 1988).
References:
Debrun GM, Viñuela F, Fox AJ, et al. Indications for treatment and classification of 132 carotidcavernous fistulas. Neurosurgery. 1988 Feb;22(2):285-9.2.
Barrow DL, Spector RH, Braun IF, Landman JA, Tindall SC, Tindall GT. Classification and
treatment of spontaneous carotid-cavernous sinus fistulas. J Neurosurg. 1985 Feb;62(2):248-56.
doi: 10.3171/jns.1985.62.2.0248. PMID: 3968564
Computed tomography angiography (CTA) imaging is performed in preparation for endovascular treatment of a basilar tip aneurysm. The CTA image shown demonstrates a dissection of the right vertebral artery. Other relevant findings identified in the CTA study include which of the following?
Answers:
A. Subclavian steal
B. Aberrant right subclavian artery
C. Fenestrated basilar artery
D. Vein of Galen malformation
E. 4 vessel aortic arch
4 vessel aortic arch
Discussion:
The left vertebral artery is usually the first branch off the left subclavian artery, but a common
anatomical variant is for it to come directly off the aortic arch (Worraputtaporn 2019). When this is
the case, the aortic arch will have 4 exiting vessels: The brachiocephalic artery, the left common
carotid artery, the left vertebral artery, and the left subclavian artery. Interestingly, the arch origin
vertebral artery usually enters the vertebral canal at C5 rather than C6.
There is no visible basilar artery fenestration or subclavian stenosis in this patient. Seeing the
Vein of Galen during the arterial phase of a catheter angiogram would suggest a venous shunt or
fistula, but all CT angiograms will have some degree of venous contamination.
References:
Woraputtaporn W, Ananteerakul T, Iamsaard S, Namking M. Incidence of vertebral artery of aortic
arch origin, its level of entry into transverse foramen, length, diameter and clinical significance.
Anat Sci Int. 2019 Sep;94(4):275-279. doi: 10.1007/s12565-019-00482-6. Epub 2019 Feb 26.
PMID: 30806941.
Tardieu GG, Edwards B, Alonso F, Watanabe K, Saga T, Nakamura M, Motomura M, Sampath R,
Iwanaga J, Goren O, Monteith S, Oskouian RJ, Loukas M, Tubbs RS. Aortic arch origin of the left
vertebral artery: An Anatomical and Radiological Study with Significance for Avoiding
Complications with Anterior Approaches to the Cervical Spine. Clin Anat. 2017 Sep;30(6):811-816.
doi: 10.1002/ca.22923. Epub 2017 Jun 12. PMID: 28547783.
A 20-year-old man is brought to the emergency department after he sustained a minor head injury. Neurological examination shows normal findings. T1-weighted with contrast and diffusion-weighted
MR images are shown. Which of the following is the most likely diagnosis?
Answers:
A. Choroid Plexus Papilloma
B. Juvenile Pilocytic Astrocytoma
C. Meningioma
D. Epidermoid
E. Glioblastoma Multiforme
Epidermoid
Discussion:
Epidermoid tumors are benign lesions that typically present between the third and fifth decades of
life. They are thought to originate from ectodermal cells misplaced during neural tube formation
and separation. Epidermoids are often paramedian, commonly at the cerebellopontine angle and
parasellar regions. Epidermoid tumors show common radiographic features. Although imaging
results may vary depending upon cystic content, CT scanning generally reveals a wellcircumscribed, non-enhancing, lobulated, hypodense mass. They are hypointense on T1-weighted
MRI, and hyperintense on T2-weighted and diffusion-weighted MR imaging.
The other choices would not restrict on diffusion-weighted imaging. Juvenile pilocytic astrocytomas
typically have a well-circumscribed lesion with an enhancing nodule and large cyst. Meningiomas
are dural-based, contrast-enhancing lesions. Choroid plexus papillomas are avidly enhancing,
intraventricular lesions. Glioblastomas have thick enhancing borders with a necrotic core.
References:
Nagasawa D, Yew A, Safaee M, Fong B, Gopen Q, Parsa AT, Yang I. Clinical characteristics and
diagnostic imaging of epidermoid tumors. J Clin Neurosci. 2011 Sep;18(9):1158-62. doi:
10.1016/j.jocn.2011.02.008. Epub 2011 Jul 13. PMID: 21742503.
Pubmed Web link: https://pubmed-ncbi-nlm-nih-gov.eresources.mssm.edu/21742503/
Nguyen JB, Ahktar N, Delgado PN, Lowe LH. Magnetic resonance imaging and proton magnetic
resonance spectroscopy of intracranial epidermoid tumors. Crit Rev Comput Tomogr.
2004;45(5-6):389-427. PMID: 15747577.
Pubmed Web link: https://pubmed-ncbi-nlm-nih-gov.eresources.mssm.edu/15747577/
Which of the following vascular abnormalities is depicted in the cerebral arteriogram shown?
Answers:
A. Thrombosis of the superior sagittal sinus
B. Vein of Labbe
C. Cavernoma
D. Cerebral arteriovenous malformation (AVM)
E. developmental venous anomaly (DVA)
developmental venous anomaly (DVA)
Discussion:
This is the venous phase of an internal carotid artery angiogram demonstrating a large
developmental venous anomaly (DVA). These lesions are commonly found in association with
cavernomas, although the cavernomas themselves are usually angiographically occult (Spetzler,
1978). Although the large draining vein of an AVM can have a similar appearance, it would likely
be seen during the arterial and/or capillary phase of the angiogram.
References:
Rigamonti D, Spetzler RF. The association of venous and cavernous malformations. Report of four
cases and discussion of the pathophysiological, diagnostic, and therapeutic implications. Acta
Neurochir (Wien). 1988;92(1-4):100-5. doi: 10.1007/BF01401979. PMID: 3407463.
Kamezawa T, Hamada J, Niiro M, Kai Y, Ishimaru K, Kuratsu J. Clinical implications of associated
venous drainage in patients with cavernous malformation. J Neurosurg. 2005 Jan;102(1):24-8. doi:
10.3171/jns.2005.102.1.0024. PMID: 15658092.
A left external carotid angiogram is obtained as part of a subarachnoid hemorrhage workup. The lateral view (Figure A) and anteroposterior view (Figure B) are shown. Which of the following arteries is indicated by the arrows?
Answers:
A. middle meningeal artery
B. Internal maxillary artery
C. Superior temporal artery
D. Occipital artery
E. vertebral artery
vertebral artery
Discussion:
The artery marked by the arrows is the left vertebral artery which is filled by collateral channels
from the occipital artery. These anastomoses are rarely seen on a catheter angiogram unless
there is occlusion of the carotid or vertebral arteries or if they are feeding a high flow vascular
malformation. Anatomical studies suggest, however, that these anastamoses, seen or not, are
present in most people (Alvernia 2006). It is particularly important to look for evidence of shunting
to vertebral artery via these collateral channels before occipital artery embolization to prevent
posterior circulation stroke.
References:
Jorge E. Alvernia, M.D., Kenneth Fraser, M.D., Giuseppe Lanzino, M.D., The Occipital Artery: A
microanatomical Study, Operative Neurosurgery, Volume 58, Issue suppl_1, February 2006, Pages
ONS–114–ONS–122, https://doi.org/10.1227/01.NEU.0000193519.00443.34
Guo Y, Chen H, Chen X, Yu J. Clinical importance of the occipital artery in vascular lesions: A
review of the literature. Neuroradiol J. 2019 Oct;32(5):366-375. doi: 10.1177/1971400919857245.
Epub 2019 Jun 12. PMID: 31188082; PMCID: PMC6728704
The lateral view cerebral angiogram shown is obtained from a 35-year-old woman. Which of the following neurological findings is most likely in this patient?
Answers:
A. hemianesthesia
B. loss of inhibition
C. visual disturbance
D. paraparesis
E. double vision
hemianesthesia
Discussion:
The AVM depicted in this angiogram is likely seated near the primary sensory cortex and would
cause hemianesthesia (and perhaps hemiparesis). Double vision or other cranial nerve palsies
would be expected for a posterior fossa AVM. Visual disturbance might be expected in an occipital
AVM. Paraparesis would more likely be caused by a spinal AVM than a cerebral AVM. Loss of
inhibition might be expected in a patient with a frontal AVM.
References:
Ding D, Yen CP, Xu Z, Starke RM, Sheehan JP. Radiosurgery for primary motor and sensory
cortex arteriovenous malformations: outcomes and the effect of eloquent location. Neurosurgery.
2013 Nov;73(5):816-24; discussio 824. doi: 10.1227/NEU.0000000000000106. PMID: 23867301
Lepski G, Honegger J, Liebsch M, Sória MG, Narischat P, Ramina KF, Nägele T, Ernemann U,
Tatagiba M. Safe resection of arteriovenous malformations in eloquent motor areas aided by
functional imaging and intraoperative monitoring. Neurosurgery. 2012 Jun;70(2 Suppl
Operative):276-88; discussion 288-9. doi: 10.1227/NEU.0b013e318237aac5. PMID: 21946511.
The lesion shown in the non-contrast T1-weighted axial (left) and T2-weighted axial (right) MR images is most commonly associated with which of the following?
Answers:
A. Cysticercosis
B. High grade glioma
C. Abscess
D. Metastasis
E. Cavernous malformation
Cavernous malformation
Discussion:
Cavernous malformations typically demonstrate a characteristic “popcorn” or “mulberry”
appearance with a rim of signal loss due to hemosiderin. While malignant neoplasms and both
pyogenic and parasitic infections tend to have different imaging characteristics, these entities must
be considered when MRI findings suggest cavernous malformation. Features of cavernous
malformation on magnetic resonance imaging include a reticulated pattern of mixed hyper- and
hypointensity on T1- and T2-weighted imaging, with a characteristic hypointense rim best
appreciated on T2-weighted imaging or gradient-echo sequences. Contrast enhancement is useful
for revealing coexisting developmental venous anomalies that are frequently associated with
sporadic cavernous malformations, and may further support the diagnosis. Susceptibility-weighted
imaging is highly sensitive for cavernous malformations and accompanying developmental venous
anomalies, and is superior to gradient-echo sequences in screening for multifocal, familial
cavernous malformations.
High grade gliomas typically have an enhancing rim and necrotic center. Metastases tend to
enhance and are usually located at the gray-white junction in the brain. Abscesses can mimic
tumors in their appearance on contrasted T1 images. They will restrict diffusion and therefore it is
important to check DWI sequences as well. The imaging appearance of cysticercosis varies with
the stage of infection.
References:
Susceptibility-Weighted Imaging for the Evaluation of Patients with Familial Cerebral Cavernous
Malformations: A Comparison with T2-Weighted Fast Spin-Echo and Gradient-Echo Sequences
J.M. de Souza et al., AJNR Am J Neuroradiol, 2008.
Wang KY, Idowu OR, Lin DDM. Radiology and imaging for cavernous malformations. Handb Clin
Neurol. 2017;143:249-266. doi: 10.1016/B978-0-444-63640-9.00024-2. PMID: 28552147.
A 40-year-old woman has right leg pain and numbness over the dorsum of the right foot. EMG
shows denervation of the right L5 nerve root. A T2-weighted MR scan without contrast is shown.
Which of the following is the most likely diagnosis?
Answers:
A. Nerve entrapment
B. Traumatic neuroma
C. Synovial cyst
D. Schwannoma
E. Fracture
Synovial cyst
Discussion:
Synovial cysts can arise from facet joints of the spine in association with degenerative arthritis,
most commonly in the lumbar spine. On magnetic resonance imaging they are typically presented
as smooth, well-circumscribed, thin-walled, unilocular, and homogeneously T2-hyperintense
lesions. An identifiable thin stalk communicating to the joint space is not infrequent. They are
rounded cystic lesions arising from the medial aspect of degenerated facet joints filled with
synovial fluid, usually smaller than 22 mm. They tend to course with lateral recess stenosis and
present dense adhesions to dura and nerve roots.
They are a well-known cause of radiculopathy and other consequences of mass effect upon
adjacent neural elements. Treatment has traditionally involved cyst resection, though reports of
cyst reduction with joint fusion exist. This lesion’s location at a joint suggests synovial cyst, rather
than a tumor (such as schwannoma) that would be foraminal associated with a nerve root. Nerve
entrapment occurs peripherally. Historical features are likely to reveal entities relating to trauma
and cysts tend not to be traumatic.
References:
Bruder M, Cattani A, Gessler F, Droste C, Setzer M, Seifert V, Marquardt G. Synovial cysts of the
spine: long-term follow-up after surgical treatment of 141 cases in a single-center series and
comprehensive literature review of 2900 degenerative spinal cysts. J Neurosurg Spine. 2017
Sep;27(3):256-267.
Neto N, Nunnes P. Spectrum of MRI features of ganglion and synovial cysts. Insights Imaging.
2016 Apr;7(2):179-86. doi: 10.1007/s13244-016-0463-z. Epub 2016 Feb 24. Erratum in: Insights
Imaging. 2016 Jun;7(3):461. PMID: 26911967; PMCID: PMC4805620.
Which of the following arteries is indicated by the arrow in the CT angiogram shown?
Answers:
A. Persistent trigeminal artery
B. Proatlantal artery
C. Persistent hypoglossal artery
D. Posterior inferior cerebellar artery
E. Vertebral artery
Persistent hypoglossal artery
Discussion:
The arrow on the CT angiogram demonstrates a left persistent hypoglossal artery. During the early
stage of fetal development, the internal carotid arteries provide the dominate blood flow to both the
forebrain and the hindbrain. The forebrain is supplied via the internal carotid arteries, similar to the
fully developed circulation. The hindbrain circulation, however, is supplied by four anastomoses
between the internal carotid arteries and two paired longitudinal neural arteries. The anastomoses
are the hypoglossal artery, otic artery, trigeminal artery, and proatlantal artery (mnemonic: HOT
Pepper). Normally, as the posterior communicating arteries and vertebral arteries develop, the
anastomoses involute. However, in a small proportion of the population they can remain into
adulthood and are referred to as persistent fetal anastomoses. The persistent fetal anastomoses
can be remembered by identifying which section of the ICA from which they originate, where the
anastomosis occurs, and through which skull base foramen they travel through (Table 1).
In the depicted CT angiogram, the artery identified is at the level of the cervical internal carotid
artery (ICA) and vertebral artery. It is clearly entering the skull base through a foramen that is not
the foramen magnum and is therefore presumed to be the hypoglossal canal. Therefore, this is a
persistent hypoglossal artery.
The artery depicted by the arrow is clearly traveling through a foramen in the skull base that is not
the foramen magnum, which would be the expected path of the vertebral artery.
A persistent trigeminal artery would be seen more distal than the depicted artery. It is identified as
an anastomosis between the cavernous ICA and the basilar artery, and commonly has a “tau”
configuration on sagittal images or a lateral catheter angiogram.
The posterior inferior cerebellar artery classically exits off the vertebral artery after it enters the
foramen magnum. The depicted artery instead travels through the hypoglossal canal.
A persistent proatlantal artery would travel through the foramen magnum alongside the vertebral
artery and not through the hypoglossal canal, as seen in the image.
Artery Start End Foramen
Proatlantal
artery
Type I:
Cervical ICA
Type II: ECA
Vertebral
artery Foramen magnum
Hypoglossal
artery Cervical ICA Basilar artery Hypoglossal canal
Otic artery Petrous ICA Basilar artery Internal auditory
meatus
Trigeminal
artery Cavernous ICA Basilar artery Petrous bone
References:
Reference (1)
Luh GY, Dean BL, Tomsick TA, Wallace RC. The persistent fetal carotid-vertebrobasilar
anastomoses. AJR Am J Roentgenol. 1999 May;172(5):1427-32. doi: 10.2214/ajr.172.5.10227532.
PMID: 10227532.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/10227532/
Reference (2)
Caldemeyer KS, Carrico JB, Mathews VP. The radiology and embryology of anomalous arteries of
the head and neck. AJR Am J Roentgenol. 1998 Jan;170(1):197-203. doi:
10.2214/ajr.170.1.9423632. PMID: 9423632
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/9423632/
A 22-year-old woman is evaluated 30 minutes after sudden onset of severe headache, wordfinding difficulty, and partial right hemianopsia. CT angiograms are shown (Figures 1-3). Which of
the following is the most likely diagnosis?
Answers:
A. Cerebral venous sinus thrombosis
B. Cavernous malformation
C. Hemorrhagic conversion of arterial stroke
D. Hypertensive microangiopathy
E. Cerebral amyloid angiopathy
Cerebral venous sinus thrombosis
Discussion:
The clinical scenario and imaging findings are consistent with cerebral venous sinus thrombosis
(CVST). Figure 1 demonstrates a lobar hemorrhage; note that the brain surrounding the
hemorrhage is hypodense, which is consistent with underlying infarct that appears to be in a
venous pattern. Figures 2 and 3 demonstrate lack of filling of the left transverse sinus, consistent
with CVST. Of note, the orientation of the head in Figure 3 is rotated so that the patient’s left is on
the left side of the image.
CVST typically presents as a headache, often without focal neurologic symptoms, in a patient with
a hypercoagulable predisposition (ie. pregnancy, post-partum, birth control, cancer). Of note, these
patients are often relatively young. If left untreated, CVST may lead to a venous stroke and
subsequent hemorrhage. The first line treatment for CVST is systemic anticoagulation, even in the
presence of intracranial hemorrhage.
Arterial stroke with subsequent hemorrhagic conversion is unlikely given that the underlying infarct
does not follow a classic arterial territory. Additionally on the CTA 3D reconstruction in Figure 3, the
arterial tree on the affected side appears patent.
Cerebral amyloid angiopathy is a common cause of spontaneous lobar hemorrhage; however, it
typically presents in older individuals (age > 65). Additionally, occlusion of the transverse sinus
would not be seen in cerebral amyloid angiopathy.
Hypertensive microangiopathy is a common cause of spontaneous hemorrhage; however, the
location is typically in the basal ganglia, thalamus, pons, or cerebellum. Additionally, occlusion of
the transverse sinus would not be seen in cerebral amyloid angiopathy.
References:
Reference (1)
Lu A, Shen PY, Dahlin BC, et al. Cerebral venous thrombosis and infarct: Review of imaging
manifestations. Appl Radiol. 2016;45(3):9-17.
Pubmed Web link
https://www.appliedradiology.com/communities/ct-imaging/cerebral-venous-thrombosis-and-infarctreview-of-imaging-manifestations
Reference (2)
Saposnik G, Barinagarrementeria F, Brown R D, et al. Diagnosis and management of cerebral
venous thrombosis: A statement for healthcare professionals from the American Heart
Association/American Stroke Association. Stroke. 2011;42(4):1158-1192.
Pubmed Web link
https://pubmed.ncbi.nlm.nih.gov/21293023
The primary arterial supply to the tumor in the cerebral angiogram shown is from which of the following arteries?
Answers:
A. Inferior cavernous artery
B. Superior hypophyseal artery
C. Tentorial artery of Bernasconi and Cassinari
D. Caroticotympanic artery
E. Inferior hypophyseal artery
Tentorial artery of Bernasconi and Cassinari
Discussion:
The MRI illustrates a petroclival meningioma, with the main blood supply based on the angiogram
provided by an artery that is coming from the cavernous segment of the internal carotid artery
(ICA). The tentorial artery, also known as the artery of Bernasconi and Cassinari, is responsible for
the primary blood supply of petroclival meningiomas. It is a branch of the meningohypophyseal
trunk (MHT), the largest and most proximal branch of the cavernous segment of the ICA. The
inferior cavernous artery is also a branch coming from the cavernous segment of the ICA but its
supply remains in the cavernous sinus. The inferior hypophyseal artery is with the tentorial and the
dorsal meningeal artery branch of the MHT but it supplies the posterior lobe of the pituitary. The
superior hypophyseal artery is a branch of the ophthalmic segment of the ICA and supplies the
anterior lobe of the pituitary gland and the stalk. The caroticotympanic artery is a branch of the
lacerum segment of the ICA. It is not consistent; but if it is present, it supplies the tympanic cavity.
References:
Tubbs RS, Nguyen HS, Shoja MM, Benninger B, Loukas M, Cohen-Gadol AA. The medial tentorial
artery of Bernasconi-Cassinari: a comprehensive review of its anatomy and neurosurgical
importance. Acta Neurochir (Wien). 2011 Dec;153(12):2485-90. doi: 10.1007/s00701-011-1195-y.
Epub 2011 Oct 14. PMID: 21997380.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/21997380/
Drummond KJ, Zhu JJ, Black PM. Meningiomas: updating basic science, management, and
outcome. Neurologist. 2004 May;10(3):113-30. doi: 10.1097/01.nrl.0000126588.14216.f3. PMID:
15140272.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/15140272
The arrow in the MR image shown is pointing to which of the following structures?
Answers:
A. Basilar artery
B. ICA
C. Jugular bulb
D. Facial nerve
E. Trigeminal nerve
Trigeminal nerve
Discussion:
By dividing the cisternal segment of the trigeminal nerve into proximal (posterior) and distal
(anterior) halves, clinicians can determine whether any encroaching blood vessels are likely to fall
on the central myelin (proximal half) or peripheral myelin (distal half). Proximal vascular
compression of the cisternal segment of the trigeminal nerve is considered more likely to be
clinically relevant, whereas distal compression is less likely to be the cause of a patient’s
symptoms.
The trigeminal nerve arises from one motor nucleus and three sensory nuclei, which extend
throughout most of the length of the brain stem. The large sensory rootlets of the trigeminal nerve
exit the lateral aspect of the midpons medial to middle cerebellar peduncle with the ophthalmic
division being most inferior, the maxillary in the middle, and the mandibular division in the superior
position. The small motor roots emerge from the pons anterosuperomedial to the entry point of the
large sensory root. The cisternal segment of the trigeminal nerve in the posterior fossa passes
forward below the tentorial edge and superior petrosal sinus between the periosteal and meningeal
(dura propria) layers of middle fossa dura to enter Meckel’s cave, a cleft-like dural pocket that
originates from the dura propria of the posterior fossa, between the two layers of the middle fossa
dura.
The internal carotid artery (ICA) passes through the carotid canal and courses superior to the
foramen lacerum before joining the circle of willis. The facial nerve also has a motor and sensory
root. It has a complex course from the mid pons to the temporal bone and through the internal
auditory canal. It passes through the facial canal, forms the geniculate ganglion and gives rise to
the greater petrosal nerve, nerve to stapedius, and chorda tympani. It finally passes the
stylomastoid foramen and gives rise to 5 motor branches. The jugular bulb lies in the jugular fossa
in the skull base and is a confluence of venous sinuses. The basilar artery is formed from the
vertebral arteries and runs ventral to the pons in the posterior circulation.
References:
Rhoton, A. L. (1900). Rhoton’s Cranial Anatomy and Surgical Approaches. Philadelphia, PA.
Seeburg DP, Northcutt B, Aygun N, Blitz AM. The Role of Imaging for Trigeminal Neuralgia: A
Segmental Approach to High-Resolution MRI. Neurosurg Clin N Am. 2016 Jul;27(3):315-26. doi:
10.1016/j.nec.2016.02.004. PMID: 27324998.
Hughes MA et al. åMRI of the Trigeminal Nerve in Patients With Trigeminal Neuralgia Secondary
to Vascular Compression. American Journal of Roentgenology. 2016;206: 595-600.
10.2214/AJR.14.14156
https://www.ajronline.org/doi/full/10.2214/AJR.14.14156
Which of the following arteries is indicated by the arrow in the lateral internal carotid artery angiogram shown?
Answers:
A. Vertebral artery
B. Persistent trigeminal artery
C. Posterior communicating artery
D. Basilar artery
E. Posterior cerebral artery
Basilar artery
Discussion:
The arrow is pointing to reflux into the basilar artery which is filling from the posterior
communicating artery. This is not necessarily an abnormal finding on its own, but may be a sign of
atherosclerosis or other vascular pathology in the posterior circulation (Wollschlaeger 1971).
The posterior cerebral arteries can be seen filling normally posterior to the basilar artery. The
vertebral arteries are more proximal to the basilar artery and do not fill in this injection. A
persistent trigeminal artery is an anomolous branch of the cavernous carotid artery to the basilar
artery. It is not present in this patient.
References:
Wollschlaeger PB, Wollschlaeger G, Lopez VF, Mathews CL, Holly JJ, Black SP. The reflux from
internal carotid artery of posterior circulation: variation of anatomy versus pathology.
Neuroradiology. 1971 Jun;2(2):65-75. doi: 10.1007/BF00337500. PMID: 5151843.
Cho L, Mukherjee D. Basic cerebral anatomy for the carotid interventionalist: the intracranial and
extracranial vessels. Catheter Cardiovasc Interv. 2006 Jul;68(1):104-11. doi: 10.1002/ccd.20712.
PMID: 16763991
The lateral view internal carotid artery angiogram shown depicts which of the following?
Answers:
A. Cavernoma
B. Cavernous carotid fistula
C. Carotid artery dissection
D. Cerebral arteriovenous malformation (AVM)
E. Cavernous sinus thrombosis
Cavernous carotid fistula
Discussion:
This lateral internal carotid artery angiogram demonstrates early filling of the cavernous sinus and
a dilated, early filling ophthalmic vein consistent with a cavernous carotid fistula. The classical
clinical triad of a CCF is chemosis, exophthalmos, and an ocular bruit, but the most common
severe complication is vision loss (Halbach, 1987). SAH, ICH, and bland infarction can occur due
to venous hypertension from a CCF, but are much less common. Ischemic stroke is a rare
complication of CCF, especially considering the shunting is arterial to venous.
References:
Halbach VV, Hieshima GB, Higashida RT, Reicher M. Carotid cavernous fistulae: indications for
urgent treatment. AJR Am J Roentgenol. 1987 Sep;149(3):587-93. doi: 10.2214/ajr.149.3.587.
PMID: 3497549.
Barnwell SL, O’Neill OR. Endovascular therapy of carotid cavernous fistulas. Neurosurg Clin N
Am. 1994 Jul;5(3):485-95. PMID: 8086801.
Which of the following is the most common major complication if the condition depicted in the internal carotid artery angiogram is not treated?
Answers:
A. intraparenchymal hemorrhage
B. ischemic stroke
C. bland venous infarction
D. vision loss
E. subarachnoid hemorrhage
vision loss
Discussion:
This internal carotid artery angiogram demonstrates early filling of the cavernous sinus and a
dilated ophthalmic vein suggesting the presence of a cavernous carotid fistula (CCF). The
classical clinical triad of a CCF is chemosis, exophthalmos, and an ocular bruit, but the most
common severe complication is vision loss (Halbach, 1987). SAH, ICH, and bland infarction can
occur due to venous hypertension from a CCF, but are much less common. Ischemic stroke is a
rare complication of CCF, especially considering the shunting is arterial to venous.
References:
Halbach VV, Hieshima GB, Higashida RT, Reicher M. Carotid cavernous fistulae: indications for
urgent treatment. AJR Am J Roentgenol. 1987 Sep;149(3):587-93. doi: 10.2214/ajr.149.3.587.
PMID: 3497549.
Barnwell SL, O’Neill OR. Endovascular therapy of carotid cavernous fistulas. Neurosurg Clin N
Am. 1994 Jul;5(3):485-95. PMID: 8086801.
A 55-year-old woman comes to the emergency department because of acute onset of headache. Physical examination shows a third nerve palsy. Non-contrast MR scans are shown. Which of the following is the most appropriate initial step in management?
Answers:
A. Craniotomy for decompression
B. Administer high-dose glucocorticoids
C. Intubate
D. Transnasal decompression
E. Contrast-enhanced MRI
Administer high-dose glucocorticoids
Discussion:
Pituitary apoplexy is a rare clinical syndrome due to ischemic or hemorrhagic necrosis of the
pituitary gland. The pituitary gland has a rich and complex vascular supply, making it more
susceptible to hemorrhage. Blood vessels within pituitary adenomas may have low fenestration,
incomplete maturation, and fragmented basal membranes that contain perivascular spaces filled
with red cells and plasma proteins, which could predispose to hemorrhage. Indeed, pituitary
tumors have a 5x greater risk of bleeding compared with other brain tumors due to the gland’s rich
vascularity. The rapid growth of a tumor and increased metabolic activity which outpaces the
development of sufficient blood supply to a tumor creates increased demand, which may
precipitate pituitary apoplexy.
Pituitary apoplexy is a medical and surgical emergency due to its association with hormonal
dysregulation, in addition to cerebral ischemia, subarachnoid hemorrhage, brain strokes, and
death. At presentation, central hypoadrenalism has been reported in more than 70% of the
patients and can have acute critical clinical consequences, including headache, visual impairment,
hypotension, nausea, and hemodynamic shock, which may require rapid administration of high
dose glucocorticoids. These patients typically do not have pulmonary or airway compromise and,
as such, hemodynamic resuscitation and help with this via high dose glucocorticoids is the priority
prior to imaging and surgical intervention.
References:
Albani A, Ferraù F, Angileri FF, et al. Multidisciplinary Management of Pituitary Apoplexy. Int J
Endocrinol. 2016;2016:7951536. doi:10.1155/2016/7951536
Liew S, Seese R, Shames A, et al. Apoplexy in a previously undiagnosed pituitary macroadenoma
in the setting of recent COVID-19 infection. BMJ Case Reports CP 2021;14:e243607.
Which of the following tasks is most likely associated with the area of activation indicated by the arrow in the MR image of the brain shown?
Answers:
A. Listening to a word
B. Seeing an object
C. Reading a word
D. Left finger tapping
E. Generating a word
Left finger tapping
Discussion:
The image shows a functional MRI (fMRI) image showing increased activation of the right
sensorimotor cortex brought about by repeated left finger tapping.
fMRI measures brain activation by detecting changes in the regional cerebral blood flow patterns.
Increased blood flow to an area alters the ratio of deoxyhemoglobin to oxyhemoglobin, which
alters the intensity of images in T2 weighted MRI sequency.
fMRI is now widely used to perform presurgical mapping of the brain, which can help guide surgery
around eloquent brain areas. A variety of tasks can be used to activate various eloquent brain
areas. Listening to words will activate the primary auditory cortex in the left temporal lobe. Reading
a word will activate the left occipitotemporal area, including the visual cortex, as well as the left
posterior temporal lobe in a person with left dominant language function. Seeing an object will
primarily activate the visual cortex in the occipital lobe. Generating a word will activate the inferior
frontal gyrus in a person with left dominant language function.
References:
Gore JC. Principles and practice of functional MRI of the human brain. Journal of Clinical
Investigation. 2003;112(1):4-9.
Pubmed Web link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC162295/
Matthews PM, Honey GD, Bullmore ET. Applications of fMRI in translational medicine and clinical
practice. Nat Rev Neurosci. 2006 Sep;7(9):732-44.
Pubmed Web link: https://pubmed.ncbi.nlm.nih.gov/16924262/
Soares, José M et al. “A Hitchhiker’s Guide to Functional Magnetic Resonance Imaging.” Frontiers
in neuroscience vol. 10 515. 10 Nov. 2016
Pubmed Web link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5102908/#B315
