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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4416_Библиотеки_им_академика_М_И_Перельмана
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A B C
Figs. 28.22A to C: Nonenhancing masses. (A) Mycetoma; (B) Retained secretions; and
(C)Frontalmucocele(withossifyingbroma).
407Chapter 28 Imaging Approach to Sinus Lesions
A B
Figs. 28.23A and B: Masses with mild-moderate enhancement. (A) Malignancies: Squamous
cellcarcinoma(SCC);and(B)Largeodontogeniclesions:Juvenileossifyingbroma.
Section 7 Clinico-Radiological Approach408
A
C
Figs. 28.24A to D: Masses with intense enhancement. (A) Antrochoanal polyp; (B) Sinonasal
angiomatouspolyp;(C)Juvenilenasopharyngealangiobroma;and(D)Hemangioma.
A
B
D
B
C
Figs. 28.25A to D: Specic patterns of enhancement. (A) Internal septal (linear) enhancement:
Antrochoanal polyp; (B) Smooth rim/mural enhancement: Sinusitis; (C) Cerebriform pattern:
Inverted papilloma; and (D) Lobular: Sinonasal angiomatous polyp.
D
Table 28.5: Dierentials according to degree and
pattern of enhancement on CECT/CEMRI.
Nonenhancing
(Figs. 28.22A to C)
• Mycetoma
• Retained
secretions
• Retention cyst
• Mucocele
(CECT: Contrast-enhanced computed tomography; CEMRI: Contrast-enhanced magnetic
reso nance imaging).
Mild-Moderate
(Figs. 28.23A and B)
• Malignancies
• Large
odontogenic
lesions
Intense
(Figs. 28.24A to D)
• Antrochoanal
polyp
• Sinonasal
angiomatous
polyp
• Hemangioma
• Juvenile
nasopharyngeal
angiobroma.
Specic pattern
(Figs. 28.25A to D)
• Internal
septal (linear)
enhancement:
Polyps
• Smooth rim/mural
enhancement:
Sinusitis,retention
cysts,and
mucocele
• Cerebriform
pattern: Inverted
papilloma
• Heterogeneous
enhancement with
necrosis: Tumors
• Lobular: Sinonasal
angiomatous polyp.
409Chapter 28 Imaging Approach to Sinus Lesions
DIFFUSIONWEIGHTED IMAGING
■ In general, benign lesions show free diusion and malignant lesions
show restriction. reshold apparent diusion coecient (ADC) value
of 1.791 × 10–3 mm2/s has been suggested for dierentiation between
benign and malignant lesions.
■ Juvenile nasopharyngeal angiobromas (Fig. 28.26A) show high mean
ADC values (> 2.168 ± 0.270 × 10–3 mm2/s).
■ However, certain lesions may show discordant behavior:
• Benign lesions which can show restricted diusion (Fig. 28.26B):
▶ Meningioma
▶ Hemangiopericytoma
▶ Solitary brous tumor.
• Malignant lesions which can show facilitated diusion (Figs. 28.27A
and B):
▶ Chondrosarcoma
▶ Fibromyxoid sarcoma
▶ Adenocarcinoma
▶ Adenoid cystic carcinoma.
8
8
9
Section 7 Clinico-Radiological Approach410
A B
Figs. 28.26A and B: Benign lesions (DWI). (A) Facilitated diffusion with high ADC value (mean
> 2.168 ± 0.270 × 10–3 mm2/s): Juvenile nasopharyngeal angiobroma; and (B) Restricted
diffusion:Meningioma.(ADC:Apparentdiffusioncoefcient;DWI:Diffusion-weightedimaging)
A B
Figs. 28.27A and B: Malignant lesions which can show facilitated diffusion. (A) Chondro-
sarcoma; and (B) Adenocarcinoma.
LOCATIONWISE RADIOLOGICAL APPROACH
■ Location within the sinonasal cavity is useful for suggesting possible
etiology.
■ e approach to lesions in the Nasal Cavity (Chapter 26) and Frontonasal:
Congenital lesions (Chapter 20) have been described elsewhere.
■ Specic sinuses (maxillary, frontal, sphenoethmoid) have certain disease
processes limited to the respective sinus.
Radiological Approach to Maxillary Sinus
■ Isolated involvement of unilateral maxillary sinus results from two
mechanisms.
■ is can be due to either ostium block or extension/complication of
dental lesion.
Flowchart 28.4: Unilateral maxillary sinus disease.
411Chapter 28 Imaging Approach to Sinus Lesions
A C
D F
Figs. 28.28A to F: Unilateral maxillary sinus involvement (ostium block). (A) Chronic
rhino sinusitis; (B) Mycetoma; (C) Antrochoanal polyp; (D) Angiomatous polyp; (E) Inverted
papi lloma; and (F) Squamous cell carcinoma.
B
E
■ is is illustrated in Flowchart 28.4.
■ Lesions which expand the infundibulum with unilateral maxillary sinus
involvement include antrochoanal polyp, sinonasal angiomatous polyp,
inverted papilloma, mycetoma, rhinoscleroma, and squamous cell
carcinoma (Figs. 28.28 and 28.29).
4
Section 7 Clinico-Radiological Approach412
A B C
Figs. 28.29A to C: Unilateral maxillary sinus involvement (extension/complication of dental
lesion). (A) Keratocystic odontogenic tumor (KOT); (B) Ameloblastoma; and (C) Infection
followingmaxillaryoordisruption.
Radiological Approach to Frontal Sinus
Based on Various Considerations
■ Acute bacterial rhinosinusitis: Although less common than maxillary
or ethmoid sinusitis, intracranial and orbital complications are more
frequent from this site. Erosion of its anterior table results in subperiosteal
swellings called “Pott’s puy tumor”.
■ Frontal sinus is also least common site of involvement with acute invasive
fungal rhinosinusitis (AIFRS), and is generally involved in combination
with other paranasal sinuses.
■ On the other hand, in allergic frontal sinusitis, the frontal sinus is involved
in more than two-thirds of cases.
■ Frontal sinus is the most common site of a mucocele.
■ Cerebrospinal uid (CSF) rhinorrhea may occur when fractures involve
the posterior table, or with involvement of frontal sinus drainage pathway.
■ Frontal sinus can also be site for encephalocele.
■ Frontal sinus is a common site for osteoma, ossifying broma, and
brous dysplasia.
■ Inverted papilloma can also occur in frontal sinus, through far less
frequently than the lateral nasal wall.
■ Rare in frontal sinus with squamous cell carcinoma still being the most
common (Figs. 28.30A to F).
Sphenoethmoidal Region (Figs. 28.31A to C)
■ e sphenoid sinus (SS) and posterior ethmoidal cells are in close
proximity, and their roof contributes to central skull base (CSB); these
are hence often considered together.
■ Lesions in this region may originate from within the sinonasal cavity or
from adjoining structures. Pituitary gland lesions may extend into the
SS inferiorly. Similarly, aggressive nasopharyngeal nasal masses may
involve SS, while cavernous sinus lesions can enter from lateral walls.
Posteriorly SS is bordered by the basisphenoid (joining upper part of
413Chapter 28 Imaging Approach to Sinus Lesions
A
C
B
D
E
Figs. 28.30A to F: Major disease entities of the frontal sinus. (A) Chronic sinusitis; (B)
Allergicfungalsinusitis;(C)Mucocele;(D)Osteoma;(E)Ossifyingbroma;and(F)Fibrous
dysplasia.
F
Section 7 Clinico-Radiological Approach414
A B
C
Figs. 28.31A to C: Disease entities of the
sphenoethmoidal region. (A) Extension of
juvenile nasopharyngeal angiobroma; (B)
Extension of pituitary macroadenoma; and
(C) Mucocele.
clivus) and posterolaterally by the petro-occipital structures. Hence,
osseous pathologies of these sites may also invade the sinus.
6
■ ere are several routes of spread from this region to cranium – superiorly
through planum ethmoidale and planum sphenoidale; laterally to cavernous sinus and to superior orbital ssure and posteriorly to clivus and
even posterior fossa.
■ Critical inferior and inferolateral relations are the vidian canal [vidian
artery—internal carotid artery (ICA) branch] and foramen rotundum
(maxillary nerve) and inferolaterally the pterygoid plexus.
■ Anatomic variants of SS pose signicant surgical risk due to proximity to
critical structures particularly ICA and optic nerve.
■ Variable pneumatization of sphenoid can appear as pseudolesions on
both CT and MRI, as can the variable MR signal of basisphenoid.
■ Sphenoid bone mostly contains medullary bone predisposing it to
hematogenous spread of diseases.
IMPORTANT DIFFERENTIALS WITH
ILLUSTRATIVE CASE FIGS. 28.32A TO F
e dierentiating features between sinusitis and malignancy
in Table 28.6.
2,5
are detailed
415Chapter 28 Imaging Approach to Sinus Lesions
A
C
E
Figs. 28.32A to F: Differentiating features of chronic invasive fungal sinusitis and
malignancy. (A)Mildlyhyperdense,lessextensivesofttissueinsinusitis;(B)Heterogeneously
enhancing, extensive soft tissue in malignancy; (C) Focal erosions with bone sclerosisin
sinusitis; (D) Extensive bone erosions in malignancy; (E) Hypointense signal on T2-weighted
image (T2WI) in sinusitis; and (F) Intermediate T2 signal in malignancy.
B
D
F
Section 7 Clinico-Radiological Approach416
Table 28.6: Dierentiating features of sinusitis and malignancy.
Sinusitis (chronic invasive
fungal sinusitis) Malignancy
CT
Soft tissue • Less extensive
• May be hyperdense
Bony changes • Sclerosis present
• Erosions in invasive forms
• Short,irregularusually
seen in region of normal
dehiscence
MRI Chronic secretions:
• T1WI: Intermediate/
hypointense
• T2WI: Hypointense
Acute mucoid secretions
• T1WI: Hypointense
• T2WI: Hyperintense.
CEMR: Peripheral rim
enhancement/mucosal
enhancement
Distribution More diffuse Mostly unilateral
Ancillaryndings – Lymphadenopathy
(CT: computed tomography; MRI: magnetic resonance imaging; T1WI: T1-weighted image;
T2WI: T2-weighted image; CEMR: Contrast enhanced MRI)
• Extensive
• Isodense to muscle
• Sclerosis absent
• Erosive changes more extensive
• Certainareas,e.g.infratemporal
surface in case of maxillary sinus
erodedinmalignancy,butnotin
sinusitis
• T1WI: Hypointense
• T2WI: Intermediate
(higher than T1WI)
CEMR: Solid enhancement ±
necrosis
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