Imaging in sinusitis radio diagnosis

1. Imaging In Sinusitis
24.10.2018
@abrakca

2. INFLAMMATORY SINONASAL
DISEASE—SINUSITIS
• inflammation of sinus mucosa.
• Acute - ≤4 weeks.
• Subacute - 4 and 12 weeks.
• Chronic - ≥12 weeks
• Recurrent acute - >4 episodes of acute sinusitis.

3. inflammatory
response to
upper
respiratory
viral infection
sinonasal
mucosal
congestion
and edema
sinus
obstruction
and bacterial
proliferation.
• Chronic sinusitis develops 2o to acute disease refractory to treatment
• generally a sequelae to interference of normal mucociliary drainag.

4. • The American Academy of Otolaryngology, in its 2007 clinical
practice guidelines, recommended against diagnostic imaging for
patients with acute or subacute sinusitis unless an intraorbital or
intracranial complication is suspected.
• Imaging is recommended in patients who fail to respond to medical
treatment, present with recurrent sinusitis, or have unilateral
recurrent symptoms when an alternate diagnosis of neoplasia or
fungal infection is suspected.

5. • CT is preferred for delineating
inflammatory sinus disease and
evaluating mucosal
abnormalities, sinus ostial
obstruction, anatomic variants,
and sinonasal polyps.
• Air spaces, opacified sinuses,
and the bony anatomy.

6. • Coronal reconstructions provide views similar to
those seen by endoscopy.
• Axial and sagittal reconstructions are especially
useful in delineating certain anatomic abnormalities,
such as an Onodi cell, or extrasinus abnormalities.

7. • characteristic features in CT
images of both chronic and acute
sinusitis include air-fluid levels,
mucosal thickening, and
opacification of the sinus cavities
that are normally air-filled.

8. • Sclerotic, thickened bone in sinus
walls is characteristic of chronic
sinusitis
• Dense opacification or opacification
with inhomogeneous
"hyperdensities" is suggestive of
thick, inspissated mucus and is a
feature of "allergic fungal
sinusitis"
• Invasive fungal disease is rare
unless the patient is
immunocompromised or has poorly
controlled diabetes.

9. • Contrast CT or MRI have a role to play when there is suspicion of an
intraorbital or intracranial extension of the disease

10. • Characteristics that are suggestive of malignancy include osseous
destruction, extra-sinus extension, and local invasion. If these
findings are noted, MR imaging should be performed to differentiate
between benign obstructed secretions and tumor and to assess for
intracranial spread.

11. Predisposing Anatomic Variants
• septal deviation
• concha bullosa
• Haller cells
• hypoplasia of maxillary sinus
• narrowing or obstruction of osteomeatal complex

12. Acute Sinusitis.
nonspecific mucosal thickening,
submucosal edema
air-fluid levels / sinus secretions with air bubbles
• Acute secretions are of mucoid nature (−10 to 25 HU) and
typically hypointense on T1 and hyperintense on T2.
• An isolated air-fluid level as the only finding in the sinus is
fairly characteristic for acute sinusitis
• Complications
• orbital cellulitis, orbital abscess, empyema, meningitis, brain
abscess, and superior ophthalmic vein and/or cavernous sinus
thrombosis.

13. Patterns of Inlammatory Sinonasal Disease
I. Infundibular pattern:
• at maxillary ostium and
infundibulum
• Limited to maxillary sinus

14. II. OMU pattern:
• middle meatus
• ipsilateral maxillary, frontal, and
anterior and middle ethmoid
sinuses
• frontal sinus may be spared
• isolated frontal sinus disease may
also occur when the obstruction is
limited to the anterior aspect of the
middle meatus.

15. III. Sphenoethmoid recess pattern:
• sphenoethmoid recess,
• sphenoid sinus and posterior
ethmoid air cells
• Isolated sphenoid disease
without posterior ethmoid sinus
disease can be seen in the SER
pattern

16. IV. Sinonasal polyposis:
• characterized by polyps diffusely
present within the nasal cavity
and paranasal sinuses, filling the
nasal vault and sinuses, causing
bilateral infundibular
enlargement, convex (bulging)
ethmoid sinus walls, and
attenuation of the bony nasal
septum and ethmoid trabeculae

17. V. Sporadic pattern:
• not attributable to obstruction of
known mucous drainage routes
or polyposis
• Individual inlammatory lesions
such as retention cysts and
mucoceles.

18. Fungal sinusitis
• is broadly divided into invasive and noninvasive forms.
• (a) invasion of the mucosa, submucosa, or blood vessels
• (b) tissue necrosis with minimal host inlammatory cell iniltration.

19. Acute Invasive Fungal Sinusitis
• poorly controlled diabetes mellitus or in immunosuppressed patients.
• nasal cavity and the middle turbinate, and a distinct predilection for
unilateral involvement of the sphenoethmoid sinuses is noted.
• fungi have a propensity to spread through the perivascular channels
and hence cross the bony sinus walls through the penetrating vessels to
reach the periantral soft tissues of the maxillofacial region, the orbit,
and the cranial cavity.

20. Acute Invasive Fungal Sinusitis
• Early features on noncontrast CT
• hypodense mucosal thickening, hypointense on T1 and hyperintense on T2
• intranasal or intrasinus soft tissue, with bony erosion.
• unilateral nasal cavity soft tissue thickening is the most consistent, though
nonspeciic, early CT finding.

21. Acute Invasive Fungal Sinusitis
Early extrasinus spread
• edema of periantral fat and within orbit across normal-appearing
walls
• Deep spread into periantral soft tissues, with destruction of sinus walls
• intraorbital and intracranial extension are late
• thickened extraocular muscles, superior ophthalmic veinthrombosis, cavernous
sinus thrombosis.
• Intracranial extension
• leptomeningeal enhancement, granulomas, cerebritis, cerebral abscess
formation, carotid artery invasion, pseudoaneurysm formation, and
intracerebral infarct and hemorrhage

22. Chronic Invasive Fungal Sinusitis
• over months to years and is also associated with high morbidity.
• in immunocompetent patients
• history of chronic sinusitis.

23. Chronic Invasive Fungal Sinusitis
• Noncontrast CT –
• mildly hyperdense soft tissue mass in paranasal sinus,
• sinus wall erosion,
• extension of the mass beyond the walls of the sinus.
• On MRI, the soft tissue is
• iso- to hypo intense on T1
• markedly hypointense on T2 sequences
• Malignancy has intermediate intensity in T2

24. Chronic Invasive Fungal Sinusitis
• intrasinus hyperdensity at CT
• chronic inspissated secretions,
• fungal infection
• intrasinus hemorrhage,
• calcifications.
• Presence of mottled irregular bone erosion is perhaps the only sign
that favors the diagnosis of an aggressive fungal infection over chronic
inspissated secretions.
• Intrasinus hyperdensity at CT almost completely excludes the
diagnosis of a sinonasal malignancy,

25. intrasinus hyperdensity at CT
• chronic inspissated secretions,
• fungal infection
• intrasinus hemorrhage,
• calcifications.

26. Noninvasive Fungal Sinusitis
• Allergic Fungal Sinusitis.
• commonest form of fungal sinusitis.
• hypersensitivity reaction to inhaled fungal organisms, resulting in a chronic
inlammatory disease process.
• warm humid climates and affects younger immunocompetent individuals
• May often be first suggested at CT, and the radiologist plays a crucial role in
alerting the physician to the possibility of this entity. Presence of allergic
mucin at endoscopy is characteristic of the disease.

27. • unilateral or bilateral but asymmetric and shows near-complete opacification
of multiple sinuses with polypoid masses
• intrasinus hyperdensity in a background of hypodense polypoid mucosal
disease, giving rise to the double-density sign.
• sinus expansion encroaching onto the adjacent orbits and erosion of the walls,
with associated extrasinus extension instead of reactive sclerosis.
• T1 variable, T2 hypo owing to metals concentrated by the fungal organisms,
high protein, and low water content of the mucin and may lead to
underdiagnoses; hence CT is best suited for the diagnosis.
• Contrast study shows enhancement of the peripheral mucosa with central areas
of nonenhancement.

28. Fungus Ball (Mycetoma)
• dense extramucosal conglomeration of fungal hyphae without any
allergic mucin,
• generally occurs in a single sinus cavity - maxillary sinus,
• CT shows a hyperdense mass due to the dense matted fungal hyphae
within the involved sinus, with occasional intrasinus calciications
• Surrounding hypodensity due to mucosal thickening is usually present,
• Reactive osteitis due to chronic sinusitis. No bony erosion is seen.
• fungus ball is hypo on T1- and T2