Transcript of Bharat pns1
- 1. Paranasal sinuses Presented by: Dr. Bharath Jain 1st year
radiology PG SSIMS& RC
- 2. Nasal cavity Nasal cavity extends from the palate to the
skull base and is divided by nasal septum. It opens posteriorly via
choana in to nasopharynx. Nasal septum comprises the septal
cartilage anteriorly and perpendicular plate of ethmoid and vomer
posteriorly.
- 3. Sinuses Air containing cavity in certain skull bones Develop
as a diverticula/outpouching from the lat wall of nose & extend
into Maxilla, Ethmoid, sphenoid and frontal bones. Each sinuses
have orifices that open into the meatus, covered by
turbinates.
- 4. Sinuses Status at birth 1st radiological evidence Adult size
reached at Maxillary sinus Present at birth 4-5 months after birth
15years Ethmoid sinus Present at birth 1year 15years Sphenoid sinus
Not present 4year 12years Frontal sinus Not present 6year
18-19years
- 5. Frontal sinuses.
- 6. Frontal recess The frontal recess is an hourglass like
narrowing between the frontal sinus and the anterior middle meatus
through which the frontal sinus drains The frontal recesses are the
narrowest anterior air channels and are common sites of
inflammation. Their obstruction subsequently results in loss of
ventilation and mucociliary clearance of the frontal sinus
- 7. Maxillary sinus Its the first sinus to form and is
hypoplastic in 10% of people. The roof forms the orbital floor and
floor is formed by the maxillary alveolus. Its medial wall forms
the lateral wall of nasal cavity. Its drains in to middle meatus
via the infundibulum.
- 8. Osteomeatal unit: It drains the frontal, anterior ethmoid
and maxillary sinuses. It includes maxillary sinus ostium, ethmoid
infundibulum, hiatus semilunaris and frontal recess. It is best
demonstrated on coronal CT.
- 9. The OMC is bounded medially by the middle turbinate,
posteriorly and superiorly by the basal lamella, and laterally by
the lamina papyracea. Inferiorly and anteriorly the OMC is
open.
- 10. Sphenoid sinus Sphenoid sinus develops in the body of the
sphenoid sinus and drains via a sinus ostium into spheno ethmoid
recess. The degree of pneumatisation is variable and may extend
into greater and lesser wing of sphenoid and pterygoid plates.
There are many important structures in relation to sphenoid sinus
like vidian canal, optic nerve and foramen rotundum.
- 11. Ethmoid air cells Thin walled air cavities in the lateral
masses of the ethmoid bone. Varies from 3 18 in number. Clinically
divided into anterior ethmoidal air cells & posterior ethmoidal
air cells, by basal lamella (lateral attachment of middle turbinate
to lamina papyracea) Anterior drain into- Middle meatus. Posterior-
sup.meatus & spenethmoidal recess.
- 12. Anatomical variants
- 13. Paradoxic Curvature Normally, the convexity of the middle
turbinate bone is directed medially, toward the nasal septum. When
paradoxically curved, the convexity of the bone is directed
laterally toward the lateral sinus wall. The inferior edge of the
middle turbinate may assume various shapes, which may narrow and/or
obstruct the nasal cavity, infundibulum, and middle meatus.
- 14. Concha Bullosa It is an aerated turbinate, most often the
middle turbinate. When the pneumatization involves the bulbous
segment of the middle turbinate, the term concha bullosa applies.
If only the attachment portion of the middle turbinate is
pneumatized, and the pneumatisation does not extend into the
bulbous segment, it is known as a lamellar concha.
- 15. Agger Nasi Air Cell Its an ethmoturbinal remnant present in
nearly all patients. Located anterior to the vertical attachment of
the middle turbinate to the skull base. The degree of ANC
pneumatization varies and has a significant effect on both the size
of the frontal sinus ostium and the shape of the recess.
- 16. Fronto-ethmoid/kunh cells/bulla frontalis Are the anterior
ethmoid cells which invade the frontal bone, bulging its floor.
They are more easily demonstrated at sagittal view, where they
appear as ethmoid air cells located above the ethmoid bulla and as
an extension towards the frontal sinus. Depending on their size and
pneumatization extent, such cells may affect the frontal sinus
drainage.
- 17. These air cells, are categorized into four types depending
on their number and degree of extension into the frontal sinus.
They are all located superior to the ANC.
- 18. Type 1 (most common): Single cell superior to the ANC that
does not extend into the frontal sinus Type 2: Two or more cells
superior to the ANC that may or may not extend into the frontal
sinus. Type 3: Single frontal cell superior to the ANC that extends
into the frontal sinus. Type 4: Completely contained in the frontal
sinus. This configuration is rare.
- 19. Haller cell These are ethmoid air cells located anterior to
the ethmoid bulla, along the orbital floor, adjacent to the natural
ostium of the maxillary sinus, which may cause mucociliary drainage
obstruction, predisposing to the development of sinusitis.
- 20. Sphenoethmoid cell (Onodi cell) This is formed by lateral
and posterior pneumatization of the most posterior ethmoid cells
over the sphenoid sinus. The presence of Onodi cells increases the
chance that the optic nerve and / or carotid artery would be
exposed in the pneumatized cell.
- 21. Accessory maxillary ostia Accessory maxillary ostia are
generally solitary, but occasionally may be multiple. Such
variation may be congenital or secondary to sinusal diseases.
Possible mechanisms involved in the development of such variation
include: main ostium obstruction, maxillary sinusitis or
anatomical/pathological factors in the middle meatus, resulting in
rupture of membranous areas.
- 22. Variations in uncinate process
- 23. Imaging modalities
- 24. X RAY CT MRI
- 25. X ray Waters view & caldwell view. CT gold standard.
Coronal & axial sections. MRI is predominantly used for pre and
post operative management of naso sinus malignancy. The chief
disadvantage of MRI is its inability to show the bony details of
the sinuses, as both air and bone give no signal.
- 26. Parietoacanthial projection: waters view
- 27. Part Position: Extend neck, placing chin and nose against
table/upright Bucky surface. Head is adjusted so as to bring the
orbito meatal line to a 45 degree angle to the casette holder.
Position the median saggital plane is perpendicular to the midline
of grid or table/upright bucky surface. Ensure that no rotation or
tilt exists. Centering is done at acanthion.
- 28. Waters view
- 29. Caldwell Part Position: Place patient's nose and forehead
against upright Bucky or table with neck extended to elevate the
OML 15 from horizontal. A radiolucent support between forehead and
upright Bucky or table may be used to maintain this
position.(alternate method if Bucky can be tilted 15.) Align MSP
perpendicular to midline of grid or upright Bucky surface.
Centering is done at nasion, ensuring no rotation.
- 30. PA PROJECTION: SINUSES Caldwell Method
- 31. 1
- 32. Parietoacanthial transoral projection: Open Mouth Waters
Method
- 33. CT procedures and techniques CT is currently the modality
of choice in the evaluation of the paranasal sinuses and adjacent
structures. Its ability to optimally display bone, soft tissue, and
air provides an accurate depiction of both the anatomy and the
extent of disease in and around the paranasal sinuses. In contrast
to standard radiographs, CT clearly shows the fine bony anatomy of
the osteomeatal channels.
- 34. SCAN LIMITS : From the ant margin of frontal sinus to post
margin of sphenoid sinus
- 35. Coronal section procedure
- 36. Axial plane Axial images complement the coronal study,
particularly when there is severe disease (opacification) of any of
the paranasal sinuses and surgical treatment is contemplated. Axial
images are particularly important in visualizing the frontoethmoid
junction and the sphenoethmoid recess.
- 37. Contrast CT Contrast is not required for all cases of CT
paranasal sinus. Used in cases such as vascular lesion, malignancy,
mass extending intra cranially, acute infections.
- 38. MRI is helpful in knowing intrcranial or intraorbital
extension.
- 39. The real value of unenhanced CT is the following: if you
see an opacified sinus with hyperdense contents, it is usually a
sign of benign disease. Tumor is not hyper-dense. The hyperdensity
is due to one or a combination of the following: Inspissated
secretions Fungus Blood
- 40. Sinusitis Sinusitis is the inflammatory condition of the
mucous membrane lining of the sinuses. It may progress to pus
formation. Sinusitis may be acute and chronic.
- 41. Sinusitis may divided into: Rhinogenous infection spreads
from the nasal cavity. It is the most common way for infection and
such sinusitis is the complication of the flu. Odontogenic
infection spreads from upper teeth. This way is typical only for
maxillary sinus. The pathologic process may spreads from 4,5,6
cheek-teeth apex to the inferior wall of the maxillary sinus
Traumatic Hematogenic Allergic.
- 42. Acute sinusitis It is an acute inflammation of the nasal
and paranasal sinus mucosa that last less than four weeks and can
occur in any of the paranasal sinuses. It usually follows viral
infection. X-ray:Opacification of the sinuses and air/fluid level
best seen in maxillary sinus.
- 43. CT Better anatomical delineation and assessment of
inflammation extension, causes and complications. Peripheral
mucosal thickening, air/fluid level, air bubbles within the fluid
and obstruction of the OMC are recognised findings.
- 44. Chronic sinusitis Chronic sinusitis refers to on going long
term sinus infection- inflammation that often develops secondary to
prolonged or refractory acute sinus infection. Allergic and fungal
sinusitis tend to be usually symmetrical and involve nasal fossa as
well as sinuses. Bacterial sinusitis involves only single or group
of contiguous sinuses. Polyps are more common in allergic rather
than infected patients.
- 45. Fungal diseases Invasivse fungal sinusitis:
-Acute/chronic/chronic granulomatus Non invasive fungal
sinusitis:
- 46. Acute invasive fungal sinusitis It is a rapidly progressing
infection seen predominantly in immunocompromised patients and
patients with poorly controlled diabetes. The disease tends to be
more rapidly progressing with relatively high mortality and
morbidity. Noncontrast CT demonstrates hypoattenuating mucosal
thickening or an area of soft-tissue attenuation within the lumen
of the involved paranasal sinus and nasal cavity
- 47. Aggressive bone destruction of the sinus walls occurs
rapidly with intracranial and intraorbital extension of the
inflammation. These fungi tend to extend along the vessels, and
extension beyond the sinuses may occur with intact bony walls. CT
is better to assess for bone changes, MR imaging is superior in
evaluating intracranial and intraorbital extension of the
disease.
- 48. Chronic invasive fungal sinusitis Inhaled fungal organisms
are deposited in the nasal passageways and paranasal sinuses.
Insidious progression occurs over several months to years in which
fungal organisms invade the mucosa, submucosa, blood vessels, and
bony walls of the paranasal sinuses. Individuals are usually
immunocompetent.
- 49. A hyperattenuating soft-tissue collection is seen at
noncontrast CT within one or more of the paranasal sinuses. Mottled
lucencies or irregular bone destruction may be seen in the
paranasal sinuses There may also be sclerotic changes in the bony
walls of the affected sinuses representing chronic sinus disease .
Infiltration of the periantral soft tissues about the maxillary
sinus is an indicator of invasive disease
- 50. Allergic fungal sinusitis It is the most common form of
fungal sinusitis. It is particularly common in warm, humid
climates. cause is thought to be a hypersensitivity reaction to
certain inhaled fungal organisms
- 51. Imaging There is usually involvement of multiple sinuses.
Disease tends to be bilateral, and there is a frequent nasal
component. The majority of the sinuses show near-complete
opacification and are expanded. Noncontrast CT demonstrates
hyperattenuating allergic mucin within the lumen of the paranasal
sinus.
- 52. Mycetoma- Fungus ball Its usually due to deficient
mucociliary clearance mechanism in which fungal organisms deposited
in the paranasal sinuses are inadequately cleared. Its common in
older individuals. The fungus ball represents a tangled collection
of fungal hyphae in the absence of allergic mucin.
- 53. Fungus ball appears as a mass within the lumen of a
paranasal sinus and is usually limited to one sinus. The maxillary
sinus is the most commonly involved sinus. A fungus ball typically
appears hyperattenuating at noncontrast CT due to dense matted
fungal hyphae and may demonstrate punctate calcifications
- 54. Sino nasal polyposis Polyps are soft tissue pedunculated
masses of oedematous hyperplastic mucosa lining the nasal cavity
and sinuses. These are benign mucosal lesions. Commonest sites in
order of frequency are: Ethmoids >>Maxillary >
Sphenoids
- 55. X ray: Opacification of nasal cavity and sinuses. Hypodense
polypoidal,rounded masses in the nasal cavity and paranasal sinuses
enlarging sinus ostium . Expansion of the sinus, thining of sinus
walls, nasal and ethmoid septa. Widening of the infundibulum.
- 56. Antrochoanal polyp Benign antral polyp which widens the
sinus ostium and extends into nasal cavity;5% of all nasal polyps.
Features: -Well defined mass with mucin density arising within
maxillary sinus. -Smooth mass enlarging the sinus ostium -No sinus
expansion.
- 57. Mucocele Mucoceles are benign, locally expansile paranasal
sinus masses most commonly found in the frontal sinus. Secondary to
obstruction of the sinus ostia, there is accumulation of fluid
within a mucoperiosteal lined cavity, resulting in erosion and
remodelling of the surrounding bone. The most common causes of
mucoceles are chronic infection, allergic sinonasal disease, trauma
and previous surgery.
- 58. The most common location of a mucocele is the
fronto-ethmoidal sinus, followed by the sphenoid sinus. The least
common location is the maxillary sinus. X-ray: will show an
expansion of the sinus cavity with loss of the scalloped margin of
the normal sinus.
- 59. Soft tissue density mass- having mucoid (15HU) attenuation.
Sinus cavity expansion. Bone remodeling at late stage but no bone
destruction Surrounding zone of bone sclerosis/calcification of
edges of mucocele(ch sinusitis).
- 60. Protrusion into orbit displacing medial rectus muscle
laterally. Expansion into subarachnoid space. resulting in CSF
leaking.
- 61. Neoplastic diseases Papillomas Carcinomas Olfactory
neuroblastoma. Lymphoma
- 62. InvertedPapilloma Occur in middle aged man. They arise from
lateral wall of nose in the region of middle turbinate. May extend
into adjacent paranasal sinuses.
- 63. CT: Features are largely non-specific, demonstrating a soft
tissue density mass with some enhancement. MRI often demonstrates a
distinctive appearance, referred to as convoluted cerebriform
pattern seen on both T2 and contrast enhanced T1 weighted images.
It refers to alternate lines of low and high signal intensity.
- 64. Fungiform papilloma These make up for half of the
papillomas. They always arise from nasal septum. They are usually
solitary and unilateral and may have an irregular surface. They do
not have malignant potential.
- 65. Carcinoma Squamous cell carcinoma: -This is the most common
type of PNS carcinoma. -Most commonly from maxillary sinus. -6th to
8th decade. -Most of them are low grade tumors arise from nasal
septum near the mucocutaneous junction. -These usually go
undiagnosed untill they involve oral cavity or cheek.
- 66. Most important feature is bone destruction even in presence
of small demonstrable mass.
- 67. Adenoid cystic carcinima These are the tumors of minor
salivary glands. They most commonly affects the maxillary sinus
among all the paranasal sinuses. They tend to spread along
perineural sheaths and tend to leave skip lesion.
- 68. Adenocarcinoma Arise from seromucinous glands. It is common
in wood workers. Non-specific imaging features- Like bone
destruction, intracranial/ intra orbital extension.. Predilection
for ethmoid sinuses
- 69. Olfactory neuroblastoma Originate from olfactory
epithelium. Bimodal age distribution with one peak in young adult
patients (~2nd decade) and another in 5th to 6th decades. These
tumours are slow growing so bony remodelling is seen rather than
bone distruction.
- 70. The lesion is very difficult to distinguish from other
malignincies except for its origin. Intracranial extension can be
seen.
- 71. Lymphoma Majority NHL. Nasal cavity and maxillary sinuses
are most common sites. These tend to be grossly bulky with good
enhancement. They tend to remodel the bone. Bony destruction is
rare.
- 72. Fibrous dysplasia FD is a condition in which medullary bone
is replaced by a poorly organized and loosely wooven bone. There
will be ground glass appearance of affected bone.
- 73. Osteoma Mature bony outgrowth. Osteomas can be of three
types: - Ivory osteoma - Mature osteoma. - Mixed.
- 74. Kerros classification
- 75. Kerros clssification
- 76. FESS Its is done to regain the drainage of sinuses. Steps:
-Septoplsty. -Uncinectomy. -Widening of sinus ostium and
infundibulum. -Unroofing of ethmoid bulla. -Frontal
sinusotomy.
- 77. Post FESS CT scan It has to be interpreted in following
ways: -Anatomical changes that have been made. -Residual or
recurrent disease. -Any complications -we have to comment on Lamina
papyracea, cribriform plate, roof of ethmoid and all other
sinuses.
- 78. Granulomatous diseases Wegners granulomatosis. TB Syphilis
Sarcoidosis. Rhinoscleroma.
- 79. Nasopharyngeal/ Juvenile angiofibroma Is a rare benign but
locally aggressive vascular tumour. Its is highly vascular and
nonencapsulated polypoidal mass that is histilogically benign but
highly aggressive. Males and 2nd decade. Site: Nasopharyngeal
region at pterygopalatine fossa or sphenopalatine foramen.
- 80. Plain film: - visualisation of a nasopharyngeal mass
-opacification of the sphenoid sinus -anterior bowing of the
posterior wall of the maxillary antrum (Holman- miller sign).
-Erosion of the medial pterygoid plate.
- 81. CT: -Typically a lobulated soft tissue mass is demonstrated
centred on the sphenopalatine foramena. -Typically bowing the
posterior wall of the maxillary antrum anteriorly. - Marked
contrast enhancement.
- 82. Thank you