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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4408_Библиотеки_им_академика_М_И_Перельмана
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M. N. L. da Silva et al.
Fig. 45.32 Coronal plane—Right ear: Pneumatized mastoid. Left ear:
sclerotic and with a veiled antrum
Fig. 45.30 Tympanosclerosis involving the ossicular chain of the left
ear. (a) Axial plane. (b) Coronal plane
Fig. 45.31 Right ear axial plane: reduction of mastoid pneumatization
and opacication. Left ear pneumatized mastoid
Fig. 45.33 xial plane—left ear. Protruding jugular bulb in the tympanic cavity (long arrow) and presence of ventilation tube in the tympanic membrane (short arrow)
Fig. 45.34 Structures seen in an upper axial plane section of the left
ear: intrapetrous carotid artery (ICA), internal auditory canal (IAC),
cochlear turns (long arrow), facial nerve (F), incudomalleolar joint
(short arrow), lateral semicircular canal (arrowhead), mastoid cells (M),
and sigmoid sinus (SS)
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Fig. 45.35 Tympanic compartment seen in the down axial plane of the
left ear: protympanum (short arrow), mesotympanum (long arrow), and
retrotympanum (middle arrow)
Fig. 45.36 Structures seen in
the coronal plane—left ear:
epitympanum (E), Prussak’s
space (long arrow), Bone
Spur of Chaussé (short
arrow), tegmen (arrowhead),
hypotympanum (H),
incudostapedial joint with
visualization of the stapes in
the oval window (middle
arrow), superior semicircular
canal (SSC), lateral
semicircular canal (LSC), and
internal auditory canal (IAC)
Fig. 45.37 Mastoid compartments seen in the coronal plane—left ear:
antrum (A), mastoid tip (T), vertical segment of the facial nerve (F),
lateral semicircular canal (L)
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Magnetic Resonance Imaging
MRI has gained space in medical practice due to its great
benet of better characterization of soft tissues. It is a noninvasive test that is based on the use of nonionizing electromagnetic radiation, where atomic nuclei are exposed to a
large magnetic eld, absorbing and re-emitting electromagnetic waves at specic frequencies. This wealth of emitted
signals generates a lot of information, depending on the
sequence used. In the context of intracranial images, radiofrequency waves stimulate hydrogen ions due to their high
concentration in biological tissue. The signal is predominantly derived from fat and water, with the fat becoming
hyperintense on the T1 sequence and the water on the T2
sequence. Structures that contain calcium or have air inside
are hypointense in both T1 and T2 [13–17].
Regarding otitis media, the use of MRI has some more
specic indications: neurological symptoms in cases with
acute or chronic otitis media, to investigate possible intracranial complications; rule out meningocele when tegmen tim-
pani is found with discontinuity on CT; involvement of the
petrous apex on CT, allowing differentiation of lesions; and
for differential diagnosis with neoplasms, when there is
suspicion.
Another very important use of MRI is in cholestetaoma
evaluation, specically in the non-echoplanar diffusion
weighted (DWI). Temporal bone CT is limited in the evaluation of recidivism in patients undergoing Wall-up tympano-
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mastoidectomy or petrosectomy, and the use of MRI-DWI
makes it possible. For this assessment, the test has a sensitivity of 90%, specicity of 100%, positive predictive value of
100%, and negative predictive value of 96%. DWI is based
on the rate of water movement in tissue and, in pathological
cases, is restricted. Thus, cholesteatoma presents with water
restriction in the MRI-DWI [14–17].
Fig. 45.38 Axial MRI (left
ear) without alterations. AB:
T1 sequence without contrast.
CD: T2 sequence. 1—
Cerebellum, 2—cochlear
nerve, 3—inferior vestibular
nerve, 4—cochlea, 5—
vestibule, 6—LSC, 7—PSC
and 8—ICA
It is important to keep in mind how the temporal bone
appears on an MRI and to know how to interpret the changes
when they are present. Findings should be consistent with
the patient’s clinic and previous CT scan. Figures 45.38,
45.39, 45.40, 45.41, 45.42, 45.43, 45.44, 45.45, and 45.46
show some ndings in MRI. Table45.5 summarizes MRI
ndings in chronic otitis media.
ab
c
d
e
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Fig. 45.39 Axial MRI (right ear) without alterations, T2 sequence. 1—Cerebellum, 2—sigmoid sinus, 3—cochlear nerve, 4—inferior vestibular
nerve, 5—facial nerve, 6—anteroinferior cerebellar artery (AICA), 7—basilar artery, 8—ICA, 9—PSC, 10—LSC and vestibule, 11—cochlear
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Fig. 45.40 Coronal MRI (normal right ear), T1 sequence without contrast. 1—Brainstem, 2—inferior vestibular nerve, 3—superior vestibular nerve, 4—cochlea, 5—vestibule, 6—LSC, 7—SSC, 8—ICA
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de
gh
ij
f
Fig. 45.41 Clinical case of cholesteatoma (right ear) with erosion of
the tegmen timpani, cochlear stula, and invasion of the geniculate gan-
glion. (a–f): axial and coronal CT sections of the temporal bones, noting cortical bone erosion of the middle fossa, cochlear turns and
kl
geniculate ganglion. (g, l): axial and coronal MRI, T1 (g, h) and T2 (i,
j, k, l) sequences, suggesting cholesteatoma (hyposignal on T1 and
hypersignal on T2)
ab
bc
a
jk
no
bc d
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Fig. 45.42 (a, b) Cholesteatoma in the petrous apex and clivus on the right ear. (a) T1 sequence, lesion with hyposignal; (b) T2 sequence, lesion
with hypersignal
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a
Fig. 45.43 (a–c) Cholesterol granuloma in the petrous apex on the
right extending into the parapharyngeal and retropharyngeal spaces. (a)
CT temporal bones, axial section. (b) Axial MRI, T1-enhanced
sequence, with a hyperintense lesion without contrast enhancement.
(b)—Axial MRI, T2 sequence, hyperintense signal
ef g
hi
lm
Fig. 45.44 (a–o) Clinical case of right petrositis due to otitis media
complication. (a–g) CT of temporal bones, axial and coronal sections,
there is opacication of the middle ear and petrous apex, in addition to
erosion of mastoid cells and the facial canal in its mastoid portion.
There is erosion of vestibule, basal turn of the cochlea and in the lateral
portion of the ICA. (h–o) MRI in axial and coronal sections, T1
sequences with contrast (h, i, l, m) and T2 (j, k, n, o), there are signs of
disease extension also to the internal auditory canal
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Fig. 45.45 (a–d) MRI in axial sections, evaluation of residual choles-
teatoma after closed left tympanomastoidectomy surgery. (a) T1
sequence, hyposignal. (b) T2 sequence, hypersignal. (c) T1 sequence
with contrast, without enhancement. (d) Diffusion restriction, indicative of disease recurrence
a b
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c d
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Fig. 45.46 (a–d) MRI in axial sections, evaluation of lesion found on CT of temporal bones for differential diagnosis. (a) T1 weighted, hyposig-
nal. (b) T2 weighted, hypersignal. (c) T1 with gd, mild capsule enhancement. (d) Diffusion restriction, indicative of cholesteatoma
Table 45.5 Radiologic interpretation on MRI within the spectrum of chronic otitis media
T1 T2 Post-gadolinium T1 DWI
Cholesteatoma Hyposignal Hypersignal No enhancement Diffusion restriction
Cholesterol granuloma Hypersignal Hypersignal No enhancement Without restriction
Effusion Hyposignal Hypersignal No enhancement Without restriction
Clinical–Radiological Correlation
Medical practice must, imperatively, be guided by a properly
collected clinical history and a complete physical
examination. The request for additional exams, regardless of
whether CT or MRI, should always be guided by prior clinical reasoning, in addition to having the objective of promoting the diagnostic hypothesis. The isolated interpretation of
the exam is not advised.
Below, we will present some cases to better elucidate this
important correlation in daily practice.
Clinical Case 1
Female patient, 17years old, with a history of frequent otitis
in the left ear for 18months, in addition to progressive ipsilateral hearing loss. Otoscopy showed marginal tympanic
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perforation in posterior quadrants with signs suggestive of
previous retraction (erosion of the long process of the incus,
timpanoestapedopexy (Fig. 45.47a, b), tympanic remnants
under the promontory) and normal middle ear mucosa on the
left. The tuning fork tests showed Weber lateralizing to the
left and Rinne negative to the left. Examination of the right
ear showed no particularities. Audiometry showing moderate
conductive hearing loss on the left ear (Fig.45.47c). CT scan
of the temporal bones presented a hypopneumatized mastoid, but without opacications (Fig.45.47d–i). Besides, it
was observed incudostapedial disarticulation and ankylosis
of the malleus head.
Clinical Case 2
Male patient, 17years old, had otorrhea in the right ear for
more than 5years, in addition to progressive ipsilateral hearing loss and tinnitus. The otoscopy showed a cholesteatoma,
and it was no longer possible to visualize the ossicular chain.
On the left, intact eardrum with retraction in the posterosuperior quadrant (Fig.45.48a). The tunning fork tests showed
Weber lateralizing to the right and Rinne was negative in
both ears. Audiometry showed moderate conductive loss on
the right and mild on the left (Fig.45.48c). Temporal bone
CT shows a clear difference between the ears (Fig.45.48d–g).
On the right, a hypopneumatized mastoid can be seen, lled
with soft tissue content, in addition to extensive erosion of
the bone spur of Chaussé and the ossicular chain. On the left,
the mastoid is pneumatized and, in the middle ear, a small
concentration of soft tissue tissue, associated with a thickened tympanic membrane, is visualized in the topography of
the incudostapedial joint.
Clinical Case 3
Male patient, 63years old reported progressive hearing loss
and bilateral tinnitus. Worked for many years in noisy environments without using protective equipment. One year ago,
he had a traumatic perforation of the right tympanic membrane. At otoscopy, a wide tympanic perforation in the right
ear with clear identication of the ossicular chain, tympanic
ostium of the Eustachian tube and round window (Fig.45.49a,
b). On the left, there were no signicant changes. Tuning
fork tests Weber lateralizing to the right and Rinne was
positive in both ears. Audiometry showed moderate mixed
hearing loss on the right and a sensorioneural deafness in
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Fig. 45.47 AI: Clinical case 1. (a, b) otoscopy. (c) audiometric exam. (d–f) CT of temporal bones, axial slices. (g–i) CT of temporal bones, coro-
nal slices. Ossicular chain discontinuity can be seen in (e) and (i). Malleus head ankylosis in D
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Fig. 45.48 (a–i) Clinical case 2. (a, b) Otoscopy. (c) Audiometric exam. (d, e) CT of temporal bones, axial slices. (f, g) CT of temporal bones,
coronal slices. Notably, there is a different pattern of pneumatization between the both mastoids
c
ab
f
d
g
Fig. 45.49 (a–g) Clinical case 3. (a, b) Otoscopy. (c) Audiometric exam. (d, e) CT of temporal bones, coronal slices. (f, g) CT of temporal bones,
axial slices. We visualized adequate aeration of the mastoid and middle ear bilaterally, in addition to a preserved ossicular chain
e
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