Download Tinnitus: What You Need to Know

Tinnitus:WhatYouNeedtoKnow
Author Contact:
Jeremy Nguyen, MD. Associate Professor of
Radiology at Tulane University Medical Center .
Email: [email protected].
EnriquePalaciosMD,FACR;JeremyNguyenMD;LorenaGarzaMD;
SarahCasIlloMD;JuanS.GomezMD;MandyWeidenhaKMD
SCHOOL OF MEDICINE
IntroducIon
Department of Radiology,
Tulane University School of Medicine, New Orleans, LA
Jugular Fossa Dehiscence
Pulsatile Tinnitus due to Vascular Anomalies
Tinnitus is the perception of sound in proximity to
the head, in the absence of a corresponding external
acoustic stimulus. This entity is a disorder with a
prevalence of 10% -15% and is more common in
men. Tinnitus sounds like ringing, hissing, static,
pulsing, buzzing, clicking or whistling. The
majority of cases are related to auditory issues
however, it is not the auditory issue itself, but the
generated BRAIN REACTIONS. Most of the
auditory pathology is associated with the cilia,
which are responsible for high frequency
transmission. The brain will try to compensate with
a mechanism known as “Homeostatic plasticity”,
which suggests that brain reactions are the culprit
for tinnitus rather than the inner ear.
A
Persistent Stapedial Artery
A
C
C
B
B
Figure 12. Persistent Stapedial Artery. CT. (A) -Axial showing absent
right-sided foramen Spinosum (yellow circle) and normal left foramen
Spinosum (yellow arrow). (B) -Coronal demonstrating small tympanic
mass adjacent to the tympanic portion of the right facial nerve canal
corresponding to the Persistent Stapedial Artery (red arrow). Angiogram
(C) showing intratympanic aberrant vessel through the Stapes giving rise
to the middle Meningeal artery. (blue arrow).
D
Figure 3. Angiograms. A revealing atherosclerotic stenosis of the Internal Carotid Artery. B
demonstrating Fibromuscular dysplasia of the vertebral artery with beaded appearance. C showing
Internal Carotid Artery aneurysms. ( arrows).
Figure 7. Jugular Fossa Dehiscence. CT. (A) -Coronal; MR post contrast. (B) and (C)
-Axial and (D) MR Venogram revealing an intratympanic mass corresponding to a
Jugular bulb within the Jugular Fossa (arrows).
tumor among others.4
protrude into the middle ear cavity.7,8
Ø  The persistent stapedial artery is an uncommon
congenital vascular anomaly that may present as a
pulsatile middle ear mass or that may appear as an
Ø  Pulsatile tinnitus may result from non-laminar blood flow caused by increased Ø  Dehiscent jugular bulbs results from the absence of the sigmoid plate that incidental finding. This entity is usually associated
normally lies between the middle ear and a high riding jugular bulb. A high with an aberrant ICA. The presence of a persistent
blood flow or a reduced vascular cross sectional area. This entity may occur in
jugular bulb can erode inner ear structures creating a jugular bulb related stapedial artery may be recognized with plain
conjunction with various diseases, such as arteriovenous malformation, high
inner ear dehiscence This dehiscent, allows the wall of the jugular bulb to
jugular bulb, dural arterio-venous fistula, intracranial hypertension, skull base
radiography, CT, or angiography. 6,12
Arteriovenous Fistula
Basilar Artery Dolichoectasia
OBJECTIVETINNITUS
• 
From identifiable intracranial causes and within the base of the
skull.
A
Figure 4. Spontaneous Arteriovenous Fistula. Digital
Angiographic exam. (A), (B ) and (C). Lateral views. MR
Venogram. (D), revealing abnormal arteriovenous
communication at the level of the Dural sigmoid sinuses.
(arrows).
A
C
B
Figure 13. Idiopathic Intracranial Hypertension. MR. (A) –Axial and (B) -Sagittal of the orbits
demonstrating papilledema manifested by dilation of the sheath of the optic nerve (yellow arrow)
and protrusion of the head of the optic nerve (red arrow). MR Venogram (C) revealing stenosis of
the bilateral transverse sinuses at the junction of the sigmoid sinuses. (blue arrows).
Figure 8. Basilar Artery Dolichoectasia.
CT (A) -Axial (B) -Coronal revealing a
markedly enlarged internal acoustic canal
(red arrows). (C). Antero posterior
Angiogram revealing an ectatic basilar
artery within the left internal acoustic
canal (yellow arrow).
Ø  Acquired Arteriovenous fistula (AVF) is
commonly associated with hearing loss and
tinnitus. Dural AVF is reported as the most
common cause of pulsatile tinnitus and may
result from an abnormal connection between
the meningeal veins and meningeal arteries.
Common locations of Dural AVF include
lateral, sigmoid and cavernous sinuses.4
D
Ø  Dolichoectasia is a marked
elongation, dilatation and
tortuosity of a blood vessel.
The incidence of intracranial
dolichoectasia ranges from
0.06% to 5.8%, with
vertebrobasilar involvement
being the most common
segment affected.9
D
Ø  Idiopathic Intracranial Hypertension
is a disorder characterized by
symptoms of elevated intracranial
pressure such as papilledema,
headaches, and vision loss. Usually
has cerebrospinal fluid composition
within reference range and no other
cause of intracranial hypertension
showed by neuroimaging.13. Frequent
in obese young females using oral
contraceptives pills.
D
C
Osteodystrophies
Carotid Aneurysm
•  Patients with tinnitus exhibit increased connectivity between the extraauditory regions including the basal ganglia, brainstem, nucleus accumbens,
cerebellum, parahippocampus, right prefrontal and parietal cortex.
•  These areas also exhibit increased connectivity: primary auditory cortex, left
prefrontal region, bilateral occipital lobes and left fusiform gyrus.
•  There is variation amongst cortical and subcortical connectivity in patients
with tinnitus, hence why other areas get affected including attention, memory
and emotions.
C
B
A
Resting-state Functional Magnetic Resonance Imaging (fMRI) of
the Auditory Network Connectivity in Tinnitus Patients
2.  Bolus-tracking measures cerebral blood volume, making use
of external contrast agents (Belliveau et al. 1991).
3.  Spin-tagging assesses cerebral blood flow, using arterial
blood for intrinsic contrast (Detre et al. 1992).
Idiopathic Intracranial Hypertension
B
-Definition:
§  fMRI study of the brain without explicit task performed by the patient.
§  Measuring the low frequency spontaneous fluctuation in the BOLD signal.
-Multiple resting state networks (RSN) have been patterned:
§  Networks contain areas of functional connectivity.
*Spatially-distinct brain regions that are simultaneously active.
§  Thought to reflect functional system supporting core perceptual and cognitive
process.
Thulborn 2006).
v  OBJETIVE TINNITUS: if it is perceived from an
identifiable cause within the cranial vault.
v  SUBJECTIVE TINNITUS: when it is perceived
without an internal or external source.
Resting State (RS) fMRI
Functional Magnetic Resonance Imaging (fMRI)
-Functional magnetic resonance imaging (fMRI) is a noninvasive imaging technique to measure and localize specific
functions of the human brain.
-Functional areas:
•  Regions of the human brain that govern motor, sensory,
language or memory functions.
-Brain function is assessed indirectly by detection of local
hemodynamic changes in capillaries and draining veins.
-fMRI measurements can be accomplished with different
techniques:
1.  Blood oxygenation level dependent (BOLD) fMRI is the
most frequently used in human brain (Thulborn et al. 1996; Thulborn 1998;
B
B
A
ClassificaIon
Dr. Juan Gomez is a visiting student from Colombia S.A.. Dr. Mandy
Weidenhaft, Dr. Enrique Palacios and Dr. Jeremy B. Nguyen are faculty
members at the Department of Radiology at Tulane University Medical
Center. Dr. Lorena Garaza is a Second year medical student at Tulane
University School of medicine in New Orleans, LA.
Special thanks to Donald Olivares, Digital Imaging Specialist, for
assistance with poster design and printing.
Blood Oxygen Level Dependent -fMRI
-The BOLD-technique mainly utilizes the different magnetic
properties of oxygenated (oxyHb) and deoxygenated (deoxy-Hb)
hemoglobin to generate the image.
§  Deoxy-Hb: Paramagnetic substance with large magnetic
susceptibility effect, producing local field inhomogeneities
resulting in signal decrease.
§  Oxy-Hb: Diamagnetic substance with small magnetic
susceptibility effect, does not interfere significantly with the
external magnetic field.
-Neuronal activity in functional area can be detected as a BOLD
signal influenced by the following factors:
•  Metabolite byproduct
•  Cerebral blood flow (CBF)
•  Cerebral blood volume (CBV)
•  Cerebral metabolic rate of oxygen (CMRO)
•  Blood oxygenation (balance of oxy-Hb and deoxy-Hb)
Auditory Resting-State Network Connectivity in Tinnitus: A Functional MRI Study. Multi Institutional Project.
PLoS ONE | www.plosone.org 1 May 2012 Volume 7 | Issue 5 | e36222.
Subjective Tinnitus and Neuroplasticity
•  Originally it was believed that tinnitus only had an auditory etiology, however
there is now evidence that the limbic system has an effect over subjective
tinnitus.
•  Based on Functional Imaging and Electrophysiology, tinnitus is now
categorized as a “Problem within the Brain Pathways” with increased
interaction between the auditory and limbic systems.
Anna Seydell-Greenwald, Erika P. Raven, Amber M. Leaver, Ted K. Turesky and Josef P. Rauschecker.
DWI, fMRI of Auditory and Auditory-Limbic Connectivity in Tinnitus: Preliminary Evidence and
Methodological Challenges; Volume 20. 2014.
Resting State for Subjective Tinnitus
C
Default mode – blue
Limbic - green
Acoustic - red
Visual – orange
Attention and task - purple
Vascular Loop Compression
B
A
Paragangliomas
A
Ø  Paragangliomas are neuroendocrine tumors arising from extraadrenal autonomic paraganglia derived from the embryonic
neural crest and usually secret catecholamines.3
q Glomus Tympanicum
A neoplasm arising from the paraganglia situated in the
vicinity of the medial promontory wall of the middle ear.3
A
B
Otosclerosis
Figure 5. Carotid Aneurysm. CT. (A) -Axial and (B) -Coronal demonstrating
bone defect corresponding to an aneurysm of the proximal intrapetrosal portion of
the Internal Carotid artery (red arrows). (C). Digital Angiogram ( yellow arrow).
Ø  Aneurysms are segmental dilations of a blood vessel.
Based on anatomical classification, aneurysms are
categorized as true or false (pseudo) aneurysms. True
aneurysms involve all layers of the arterial wall (intima,
media and adventicia). In pseudoaneurysms, the wall of
the blood vessel is ruptured and blood leaks into
surrounding tissues. Common risk factor reported for a
true aneurysm is atherosclerosis and for a false
aneurysm is trauma.5
.
C
10
Figure 9. Otosclerosis. CT. (A) and (B) -Axial demonstrating an otosclerotic
focus at the right oval window / fissula ante fenestram (arrows). CT. (C) -Axial
showing postsurgical changes with stapes prosthesis in place at the oval window.
C
Superior Semicircular Canal Dehiscence
C
D
Figure 14. Vascular Loop Compression. MR. (A) and (B) –Axial, (C) Coronal; MR Angiogram
-Coronal showing vascular loop of the distal left vertebral artery at the left cerebellopontine
angle compressing the left Facial nerve (arrows).
Figure 15. BOLD imaging of primary auditory cortex (red
arrow) adjacent to a cavernoma (yellow arrows).
C
Figure 1. Glomus Tympanicum. CT. (A) -Axial, (B) -Coronal; MR post contrast.
(C) -Coronal revealing an enhanced soft tissue mass in the hypotympanum of the
left middle ear (arrows).
C
q Glomus Jugulare
A A
A
Figure 2. Glomus Jugulare. MR post contrast. (A)
-Axial, B. -Coronal
demonstrating an
inhomogeneous enhancing soft tissue mass in the
left jugular fossa (red arrows). CT. (C) -Axial
revealing an enlarged jugular fossa with irregular
erosions (yellow arrow) .
C
B
C
Figure 6. Aberrant / Ectopic Internal Carotid Artery (ICA). CT. (A ) and (B) -Axial;
Angiographic examination (C) revealing developmental dehiscence of the carotid canal with an
ectopic ICA within the tympanic cavity (arrows).
B
Ø  An aberrant ICA is a variant of the carotid artery and represents a collateral
pathway resulting from involution of the normal cervical portion (first
embryonic segment) of ICA. Characteristic angiographic findings of aberrant
ICA include lateral extension of the ICA well beyond the vestibular line of
Lapayowker. CT is considered one of the most reliable ways to diagnose an
aberrant ICA.6
B
Ø  In superior semicircular canal dehiscence syndrome, the
middle fossa and superior semicircular canal communicate
abnormally resulting in deficient vestibular function.
Symptoms may include conductive hearing loss, vertigo and
tinnitus.11
Figure 10. Superior
Semicircular Canal
Dehiscence. CT. (A) -Coronal
and 3D reconstruction (B).
Demonstrates dehiscence of
the superior semicircular canal
(red arrows). CT. (C) and (D);
3D reconstruction (E).
Revealed normal examination
within the superior
semicircular canal (yellow
arrow).
• 
B
• 
•  Tinnitus without an identifiable intracranial or
external source.
References
1. 
2. 
3. 
4. 
Lanting CP, de Kleine E, Langers DRM, van
Dijk P (2014) Unilateral Tinnitus:
Changes in Connectivity and Response
Lateralization Measured with fMRI.
PLoS ONE 9(10): e110704. doi:10.1371/
journal.pone.0110704
http://127.0.0.1:8081/plosone/article?
id=info:doi/10.1371/journal.pone.0110704
BOLD-fMRI study of auditory cortex in
patients with tinnitus MAO Chun-li, CHEN
Xian-ming, CHEN Zi-qian, YE Youqiang2, LUO Ping. Department of
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C
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E
Schmidt et al., Burton et al., 2002.
Maudoux et al., 2012. Kim et al., 2012
Many of the supposed anatomic changes associated with tinnitus are frequently
encountered in asymptomatic patients.
Correlation between imaging findings and the clinical picture is usually in
discordance.
Resting State fMRI offered some evidence of involvement of non-auditory
functional areas.
• 
Figure 16. BOLD imaging shows activated
areas :
-  Medial geniculate ganglion (MGL).
-  Inferior colliculus (IC).
-  Some cranial nerves (CN).
A
Figure 18.
•  Strong relationship in patients with tinnitus
(solid lines).
•  Less solid relationships (dotted lines).
Conclusions
Ø  Vascular compression syndrome
describe a clinical entity
characterized by compression of one of the cranial nerves by a
vessel and may result in vascular perfusion reduction, focal
demyelination and axonal hyperactivity.14,15
SUBJECTIVE TINNITUS
B
A neoplasm arising from
the paraganglia situated in
the vicinity of the jugular
bulb. May involve Cranial
Nerves: IX, X, XI.3
Ø  P r o g r e s s i v e h e a r i n g l o s s
characterized by abnormal bone
remodeling in the otic capsule and
multifocal areas of sclerosis within
the endochondral temporal bone.
Symptoms may include hypoacusis,
conductive hearing loss and tinnitus.
A
Aberrant - Ectopic Carotid Artery
A
B
B
19. 
Figure 17. Extensive activation of non-auditory regions in a patient with
bilateral tinnitus in response to stimuli to left ear.
20. 
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