1. By; Dr Shaista Bashir

2. Polyps are soft tissue pedunculated masses ofoedematous hyperplastic mucosa lining theupper respiratory tract..nasal cavity andsinuses. These are benign mucosal lesions. 3. Commonest sites in order of frequency are;1. Ethmoids2. Maxillary antra3. sphenoids 4. 1. Allergic rhinitis2. Asthma3. Cystic fibrosis(child)4. Kartagener syndrome5. Nickel exposure6. Nonneoplastic hyperplastic hyperplasia of inflammed mucous membranes. 5. Views;Waters,caldwell,lateral,submental vertexFeaturesOpacification of nasal cavity and sinuses 6. SSCT IS THE MODALITY OF CHOICE CT is of value for determining anatomical landmarks and variants,to identify erosive changes,e xcellent to determin intraorbital extension of sinonasal disease upto the ventral 2/3rd of the orbit. when disease approaches apexMRI is next step to assess spread to the cavernous sinus and intracranial extension. Non enhanced CT is performedvalue of NECT is the following;if u see an opacified sinus with hyperdense content it is usually a benign disease.hyperdensities are due to,blood,fungus,inspissated secretions. FEATURES1. Hypodense polypoidal,rounded masses in the nasal cavity and paranasal sinuses enlarging sinus ostium . 7. 2.Expansion of the sinuse,thining of sinus walls,nasal and ethmoid septa.3.Bulging of the lamina papyracea leading to displacement of the eyeballs and hypertelorism4.Widening of the infundibulum.5.On post contrast images show peripheral or occasionally solid heterogenous enhancement.6. Erosive changes at anterior skull base. 8. SSCT 9. SNP 10. THINING OF SEPTAE 11. Reserved for difficult cases especially where isdoubt about the pathology on SSCT. MRI is also useful to assess any intracranial ororbital involvement. 12. Benign antral polyp which widens the sinus ostium and extends into nasal cavity;5% of all nasal polyps. Age Teenagers and young adults Features1. Antral clouding2. Ipsilateral nasal mass3. Smooth mass enlarging the sinus ostium4. No sinus expansion 13. . A sphenochoanal polyp is a solitary mass of low attenuation on computed tomographic (CT) scans that arises from the sphenoid sinus and extends through the sphenoid ostium, across the sphenoethmoid recess, and into the choana (the boundary between the nasal cavity and nasopharynx). Contiguous axial or coronal magnetic resonance and CT images help clearly differentiate the rare sphenochoanal polyp from the more common antrochoanal polyp. The sinus of origin is important to identify, as the surgical approach depends on the target sinus. 14. Sinusitis(air fluid levels,totalopacification,enhancementpattern,hyperintense secretion on T1WI,rimenhancement on post gad) Cancer(solid central enhancement). Fungal disease(focal or diffuse areas ofincreased attenuation on ct,signal voids onmri,rim enhancement on mri). Juvenile angiofibroma(involvement ofpterygopalatine fossa). 15. pns 16. Mucocele is end stage of a chronicallyobstructed sinusanobstructed,airless,mucoid filled expandedsinus.Location;Frontal(60%),ethmoid(30%).maxillary(10%),sphenoid (rare)CAUSES. The most common causes of mucoceles are chronicinfection, allergic sinonasal disease, trauma and previous surgery. 17. Soft tissue density mass.having mucoidattenuation. Sinus cavity expansion Bone demineralisation+remodelingat late stagebut No bone destruction(DDx from neoplasm) Surrounding zone of bonesclerosis/calcification of edges of mucocele(chsinusitis). 18. Macroscopic calcification in 5%(superimposedfungal infection) Uniform thin rim enhancement. Protrusion into orbit displacing medial rectusmuscle laterally. Expansion into subarachnoid space. resultingin CSF leaking. 19. ct 20. cct 21. cct 22. ethmoid 23. Intracranial extension 24. Paranasal sinus carcinoma Aspergillus infection Ch infection Inverting papilloma 25. X-ray ;will show an expansion of the sinuscavity with loss of the scalloped margin of thenormal sinus. Sinus is opaque than normal due to secretionsbut may on occasions appear more radiolucentif bone destruction is marked. CT;will show the full extent of expansion and isusually enough to make the diagnosis. MRI;may be used to assess the intracranialextent. 26. Clinically more obvious as palpable mass atmedial canthus ofeye,proptosis,epiphora..expansion on lacrimalsac. Majority are found in the anterior ethmoidcells,expansion of the posterior ethmoid cellsare less common and are associated withsphenoid mucoceles. 27. Rare Involvement of optic nerve,cavernous sinus and3rd nerve is common due to proximity to thesestructures. Imaging plays a key role in diagnosis and itsimportant that condition be recognized by theradiologist at an early stage and dealt surgicallybefore vision is compromised. CT and MRI show rounded or partially roundedexpansion of the sphenoid sinus as opposed to thedestruction of bone in situ caused by malignancy. 28. Signal intensity varies with state ofhydration,protein content,hemorrhage,aircontent,calcification,fibrosis. Hypointense on T1W1+signal void on T2W1due to inspissated debris+fungus. Hydrated secretions are hypo on T1W1 andhyperintense on T2W1. Peripheral enhancement pattern(DDxneoplasm). 29. Fungal disease of the paranasal sinuses isusually diagnosed when an apparent routineinfection fails to respond to normal antibiotictreatment. Acute invasive fungal sinusitis;is the mostaggressive form of fungal sinusitis.it is seen inimmunocompromised patients and source ofmorbidity and mortality. Clinical features;are rapid development offever,facial pain,nasal congestion and epistaxis. 30. Extension into orbit,cavernous sinus and intracranial compartment results in decreased vision.proptosis and neurological deficits.Pathology ;originates in the nasal cavity mostly in the middle turbinate with subsequent spread into the paranasal sinuses.a number of fungal agents are implicated..1.Aspergillus2.Rhizopus3.Mucor4.Absidia 31. Ethmoids,maxillary antra are commonlyinvolved,sphenoid sinus may be occasionallyinvolved,frontal sinuses are rarely affected. Mucosal thickening:hypoattenuating Bone destruction:extensive/subtle Fat stranding outside ofsinus..intraorbital,pterygopalatinefossa,masticator space. Punctate calcifications.diffuse,nodular orlinear 32. sephnoethmoid 33. cct 34. MRI POST GAD 35. MRI is the modality of choice to asses soft tissueextension. The findings within the sinus itself arevariable, and range from mucosal thickening, tocomplete opacification of the sinus. T1 : intermediate low signal T2 fungal mass is of intermediate to low signal often associated with fluid / blood elsewhere in the paranasal sinuses T1 C+ (GAD) : peripheral enhancement only Hypointense on all sequences due to paramagneticeffect of heavy metals high fungal mycelialiron,magnesium,manganese content from amino acidmetabolismDDx from inspissatedsecretions/polypoid disease. Low signal on T1 and T2 when there is fibrosis. 36. Complications include : intraorbital extension intracranial extension leptomeningeal enhancement intracranial granulomas epidural abscess vascular invasion cavernous sinus thrombosis or dural venous sinusthrombosis mycotic aneurysm formation cerebral infarction or cerebral haemorrhage systemic dissemination 37. Differential diagnoses acute sinusitis blood clot sinonasal carcinoma mucocoele