CT & MR Imaging of the CT & MR Imaging of the Paranasal Sinuses with special Paranasal Sinuses with special

reference to FESSreference to FESS

Dr Himadri Sikhor Das,Dr Himadri Sikhor Das,Dr P.Hatimota,Dr P.Hazarika,Dr C.D.ChoudhuryDr P.Hatimota,Dr P.Hazarika,Dr C.D.Choudhury

MATRIXMATRIX

ContentsContents

CT anatomy of sinonasal cavity for CT anatomy of sinonasal cavity for FESS:FESS:

- Concept of FESS.Concept of FESS.- Ostiomeatal Complex (OMC) & normal Ostiomeatal Complex (OMC) & normal

variantsvariants- Complications of FESS.Complications of FESS.- Imaging findings of variousImaging findings of various

infectious/inflammatory sinonasal infectious/inflammatory sinonasal diseasedisease

Paranasal sinusesParanasal sinuses Functions of the PNS:Functions of the PNS:- Warms & humidifies Warms & humidifies

inspirated air.inspirated air.- Filters small airborne Filters small airborne

particulate matters particulate matters

- Drains secretions from - Drains secretions from paranasal sinuses to paranasal sinuses to the nasal cavity the nasal cavity

- Traps odor-bearing - Traps odor-bearing particles for olfactionparticles for olfaction

HRCT scan protocolHRCT scan protocol

Protocol: Axial Coronal: Protocol

Axial CTAxial CT

Coronal HRCT for OMUCoronal HRCT for OMU

Sagittal Sagittal

Coronal HRCTCoronal HRCT

Normal nasal cycle:Normal nasal cycle: periodic alternate functioningperiodic alternate functioning

of secretory activityof secretory activity

nonfunctioning

functioning

Basic Concept of FESS:Basic Concept of FESS:

Why Why “ Functional”“ Functional” “ “ Maintenance of Maintenance of

the normal pathway the normal pathway for mucociliary for mucociliary clearance by clearance by relieving the ostial relieving the ostial obstruction & obstruction & preserving the preserving the normal mucosa of normal mucosa of the sinonasal the sinonasal cavity”cavity”

Osteomeatal unit/complex Osteomeatal unit/complex (OMU/OMC)(OMU/OMC)

Anterior OMU drains Anterior OMU drains frontal maxillary , frontal maxillary , anterior and middle 1/3anterior and middle 1/3rdrd of ethmoid sinuses. of ethmoid sinuses.

The uncinate process ( UP The uncinate process ( UP ) and lateral wall of nasal ) and lateral wall of nasal cavity forms the ethmoid cavity forms the ethmoid infundibulum ( EI ). infundibulum ( EI ).

The above sinuses drain The above sinuses drain into the EI via various into the EI via various ostia.ostia.

The posterior OMC The posterior OMC located in spheno ethmoid located in spheno ethmoid recess, drains posterior recess, drains posterior 1/31/3rdsrds of ethmoid and of ethmoid and sphenoid sinuses. sphenoid sinuses.

HRCT-Sinonasal anatomyHRCT-Sinonasal anatomy

HRCT-Sinonasal anatomyHRCT-Sinonasal anatomy

Nasal EndoscopyNasal Endoscopy

Anatomical VariantsAnatomical Variants

Anatomical VariantsAnatomical Variants

Anatomical VariantsAnatomical Variants

Look for :Look for :

Concha bullosa with type-II Concha bullosa with type-II OFOF

Surgical therapy for sino-nasal Surgical therapy for sino-nasal diseasesdiseases

Indirect sinus procedure:Indirect sinus procedure: - - septoplastyseptoplasty - - adenoidectomyadenoidectomyDirect sinus procedure:Direct sinus procedure: - - antral lavage & sinus aspirationantral lavage & sinus aspiration - - Nasal antral windowsNasal antral windows - - Middle meatal antrostomyMiddle meatal antrostomyFunctional Sinus surgery:Functional Sinus surgery: - - Endoscopic (FESS)Endoscopic (FESS)

FESS: ComplicationsFESS: Complications Minor local complications:Minor local complications: periorbital emphysema, epistaxis, tooth periorbital emphysema, epistaxis, tooth

pain, post operative nasal synechiae.pain, post operative nasal synechiae. Orbital complications:Orbital complications: orbital emphysema, haematoma, orbital emphysema, haematoma,

abscessabscess injury to NLD/EOM/optic nerveinjury to NLD/EOM/optic nerve CSF leakage:CSF leakage: No trespassing the medial to vertical No trespassing the medial to vertical

lamella of middle turbinatelamella of middle turbinate Intracranial complications:Intracranial complications: Intracranial haematoma, abscess, Intracranial haematoma, abscess,

encephalocelesencephaloceles Injury to intracranial vesselsInjury to intracranial vessels

FESS: ComplicationsFESS: Complications

FESS: ComplicationsFESS: Complications

Sinusitis & Sino nasal Sinusitis & Sino nasal diseasesdiseases

PathophysiologyPathophysiology Most common cause of frontal and Most common cause of frontal and

maxillary sinusitis is anterior ethmoid maxillary sinusitis is anterior ethmoid disease with superimposed rhinitis. disease with superimposed rhinitis. ( viral / bacterial). ( viral / bacterial).

Diseased mucosa of the draining Diseased mucosa of the draining ostia leads to impairment of ostia leads to impairment of secretions and mucociliary clearance.secretions and mucociliary clearance.

Treating anterior ethmoid disease Treating anterior ethmoid disease clears frontal and maxillary sinusitis.clears frontal and maxillary sinusitis.

Sinusitis: Sinusitis: inflammation/infection of 1 or inflammation/infection of 1 or more paranasal sinusesmore paranasal sinuses

ACUTE:ACUTE: symptoms lasting <3 weekssymptoms lasting <3 weeks - Air fluid level- Air fluid level - Mucosal thickening - Mucosal thickening

SUBACUTE:SUBACUTE: symptoms lasting 3 wk to 3 symptoms lasting 3 wk to 3 monthsmonths - Mucosal thickening - Mucosal thickening

CHRONIC : CHRONIC : - - symptoms lasting >3 symptoms lasting >3 monthsmonths

- Ethmoid disease MC.- Ethmoid disease MC. - Mucosal thickening to sinus - Mucosal thickening to sinus opacificationopacification - Bony remodelling- Bony remodelling - Polyposis- Polyposis

““Acute or chronic can not be determined based Acute or chronic can not be determined based on a single examination”on a single examination”

Plain filmPlain film - Caldwell for frontal and ethmoids - Caldwell for frontal and ethmoids

- Water’s for maxillary and sphenoid - Water’s for maxillary and sphenoid

- - lateral and submentovertex for lateral and submentovertex for sphenoidsphenoid

SinusitisSinusitis

Inflammatory sinonasal Inflammatory sinonasal diseasedisease

TYPES:TYPES:

A.A. SIMPLE:SIMPLE:

B.B. ADVANCED:ADVANCED:

-Infundibular pattern-Infundibular pattern

-OMU pattern-OMU pattern

-Spheno-ethmoidal -Spheno-ethmoidal recess patternrecess pattern

-Sinonasal polyposis-Sinonasal polyposis

-Sporadic or -Sporadic or unclassifiable patternunclassifiable pattern

High dense foci in CT & High dense foci in CT & signal void on MRIsignal void on MRI

Fungal sinusitisFungal sinusitis Intrasinus hemorrhageIntrasinus hemorrhage Chronic inspissated mucusChronic inspissated mucus Long standing polypLong standing polyp MucoceleMucocele Sinolith/osteoma/intrasinus toothSinolith/osteoma/intrasinus tooth

Chronic inspissated Chronic inspissated mucusmucus

Normal sino nasal Normal sino nasal secretions:secretions:

- (Water 95% + (Water 95% + macromolecular macromolecular proteins(5%)proteins(5%)

Chronically Chronically obstructed sino-obstructed sino-nasal secretions:nasal secretions:

- - Increased proteinIncreased protein content & content & viscosityviscosity with with reduced free reduced free waterwater

Sinonasal polypoidal lesionsSinonasal polypoidal lesions

PolypsPolyps

AC & SC polypsAC & SC polyps

Antrochoanal polypAntrochoanal polyp

Spheno-choanal PolypSpheno-choanal Polyp

Sinonasal polyposisSinonasal polyposis

Sinusitis: Local Sinusitis: Local complicationscomplications

Mucus retention cyst:Mucus retention cyst:- - Inflammatory Inflammatory

obstruction of obstruction of seromucinous glandsseromucinous glands

Polyp:-Polyp:- - Mucosal folding with - Mucosal folding with

submucosal fluid submucosal fluid collectioncollection

-Allergy/atopy/Vasomotor -Allergy/atopy/Vasomotor impairment/DM/Cystic impairment/DM/Cystic fibrosis/aspirin /chronic fibrosis/aspirin /chronic nickel exposure may nickel exposure may cause bone erosioncause bone erosion..

Sinusitis: Local Sinusitis: Local complicationscomplications

Mucocele:Mucocele:

- Airless expanded sinuses surrounded - Airless expanded sinuses surrounded by mucous secreting respiratory by mucous secreting respiratory epithelium, resulting from ostial epithelium, resulting from ostial obstruction.obstruction.

- Frontal(60-65%),Ethmoid(20-- Frontal(60-65%),Ethmoid(20-25%),Maxillary(10%),sphenoid (1-2%)25%),Maxillary(10%),sphenoid (1-2%)

- Bony remodeling by pressure erosion.Bony remodeling by pressure erosion.- Varied density/SI on CT / MRVaried density/SI on CT / MR

MucoceleMucocele

Sinusitis: other Sinusitis: other complicationscomplications

Orbital complications:Orbital complications: E>S>F>ME>S>F>M - Preseptal or orbital cellulitis /subperiosteal - Preseptal or orbital cellulitis /subperiosteal

abscess or phlehmon/ thrombophlebitisabscess or phlehmon/ thrombophlebitis Intracranial complications:Intracranial complications: F>S>E>MF>S>E>M - Meningitis/epi or subdural - Meningitis/epi or subdural

abscess/cerebritisabscess/cerebritis - Venous sinus thrombosis/brain abscess- Venous sinus thrombosis/brain abscess Subgaleal abscess/Osteomyelitis / Pott’s Subgaleal abscess/Osteomyelitis / Pott’s

puffy tumorpuffy tumor /Osteo- thrombophlebitis due to frontal /Osteo- thrombophlebitis due to frontal

sinusitis.sinusitis.

Preseptal& orbital Preseptal& orbital cellulitiscellulitis

Fungal Sinusitis: Non Fungal Sinusitis: Non invasive formsinvasive forms

Mycetoma & Allergic Fungal SinusitisMycetoma & Allergic Fungal Sinusitis Maxillary>Ethmoid > Sphenoid>FrontalMaxillary>Ethmoid > Sphenoid>Frontal Imaging Findings:Imaging Findings: - Non specific mucosal inflammation- Non specific mucosal inflammation - Mixed sclerosis/erosion of bony walls- Mixed sclerosis/erosion of bony walls - High dense foci on CT- High dense foci on CT - Signal void on MR- Signal void on MR - Air fluid levels-- Air fluid levels-veryvery uncommonuncommon

Fungal Sinusitis: Fungal Sinusitis: Invasive formsInvasive forms

* * Immunocompromised hostsImmunocompromised hosts

- DM- DM

- Impaired neutrophil function- Impaired neutrophil function

* Rhino-cerebral mucormycosis * Rhino-cerebral mucormycosis /aspergillosis/aspergillosis

* Vascular invasion: * Vascular invasion:

- - Thrombosis & tissue necrosisThrombosis & tissue necrosis

Allergic Fungal Sinusitis

Thank You !!Thank You !!