Radiology in ent

RADIOLOGY IN ENT

1. RADIOLOGY IN ENT

2. Classification Non radiation dependent Ultrasounds MRI Radiation dependent Conventional X Rays CT Scan Prefer non radiation scans if needed frequently to avoid adverse effects like carcinoma, genetic defects

3. Reading of radiograph Type – plain/contrast View – AP/lateral Region – mastoid/PNS/neck Identify normal landmarks Identify the pathology – opacity/mass/bone destruction Radiological diagnosis

4. Conventional X Rays Principle – x rays are absorbed differently by soft tissue, bone, air, fluid, fat X RAYS TEMPORAL BONE/MASTOID LAWS VIEW Lateral view mastoid X ray beam propelled 15 degree cephalocaudal Can study mastoid air cells, sinus plate, TM joint Cant see well attic, aditus , antrum as two side mastoid superimpose

5. SCHULLERS VIEW Lateral oblique view of mastoid X ray beam propelled 30 degree cephalocaudal No superimposition of two mastoid bones Separate for right and left mastoid Structures seen – mastoid air cells, EAC, dural plate, sinus plate, sino dural angle, TM joint, aditus , attic, antrum

6. To see extent of pneumatization – well pneumatized (honey comb appearance with intercellular septa), sclerotic (radio opacity with destruction of intercellular septa seen in mastoiditis ) Sclerotic with mastoid erosion seen as translucent area – cholesteatoma , post op, TB, malignancy Erosion of sinus and dural plate – intra cranial complications

7. TOWNES VIEW AP view of skull Both the temporal bones can be seen and compared with one another IAC, petrous pyramid, arcuate eminence, sup scc , cochlea Acoustic neuroma TRANS ORBITAL/PERORBITAL VIEW IAC, cochlea, labyrinth, petrous pyramid Acoustic neuroma

8. SUBMENTOVERTICAL VIEW Ossicles , middle ear cavity, ET, EAC, mastoid cells OWENS VIEW Ossicles , EAC, epitympanum , mastoid antrum STENVERS VIEW Petrous pyramid, apex, IAC, cochlea Petrositis

9. NOSE AND PNS Normally nasal cavity and PNS are air filled so translucent Bony wall seen as white thick line WATERS VIEW AP view of PNS Occipito mental view Nose chin view Nose and chin touch the film X ray beam from occipital side Open mouth – to examine sphenoid sinus

10. Best view – all PNS seen But best for maxillary sinus Fracture of right and left nasal bone Fracture of sinus wall Radio opacity – significant if greater than orbit Total opacity – sinusitis, polyp, malignancy, mucocele Partial opacity with air fluid level – due to pus in acute sinusitis Round opacity – polyp, cyst, AC polyp – opacity also in nasopharynx , Dense opacity – osteoma Destruction of wall - malignancy

11. CALDWELL VIEW Occipito frontal view or nose forehead view Nose and forehead touch the film Best for frontal sinus Sup margins of orbit Ethmoidal sinus, maxillary sinus OBLIQUE VIEW Post ethmoidal sinus

12. LATERAL VIEW Pterygopalatine fossa , sphenoid sinus, hard palate, sella turcica BASAL VIEW Submento vertical view Sphenoid sinus Post ethmoid Base of skull

13. NASAL BONES Lateral view Occlusal view Rt or lt Fracture line Depression, elevation, displacement of fractyure segment

14. SOFT TISSUE NECK Lateral view Post tongue, hyoid bone, epiglottis, tracheal shadow, prevertebral space, cervical vertebra AP view Displacement or compression of trachea, FB Acute epiglottitis Thumb sign Fracture larynx, hyoid bone Laryngeal stenosis Spine injury

15. Retropharyngeal abscess Widening of prevertebral area (increase in shadow) greater than 2/3 rd of AP dimension of adjacent vertebral body Straightening of cervical spine due to reflex spasm of muscles If TB – destruction or collapse of vertebra along with RP abscess

16. FB oesophagus Radio opaque FB – coin, chicken/mutton bone, wire of dentures Level of FB impaction on lateral view – by counting the vertebra downwards starting from C1 MC Site – C5-C6 vertebra ( cricopharynx ) Position – AP view – face of coin seen (coronal shadow) Lateral view – edge of coin seen (linear shadow) behind tracheal air shadow in front of vertebra FB trachea – AP – edge of coin, lateral – face of coin

17. NASOPHARYNX Soft tissue mass Lateral view Patient to breathe quietly through nose Adenoids – no air column, mass seen AC polyp – air column between soft tissue mass and posterior wall Angiofibroma , choanal atresia , FB Base of skull view – to assess spread of ca

18. Submandibular gland – lateral view with floor of mouth depressed with wooden spatula – radio opaque calculi seen Parotid gland – lateral oblique view with open mouth Orthopantomogram – visualisation of entire maxillary and mandibular dentition along with alveolar arches

19. BARIUM SWALLOW Contrast study from oral cavity to fundus of stomach for mainly lesions below cricopharynx Contrast – barium sulfate Achalasia – proximal dilatation of oesophagus with smooth tapering – rat tail appearance Strictures – smooth narrowing seen Varices – irregular filling defect Dysphagia Pharyngeal pouch

20. Oesophageal perforation FB Malignancy – irregular narrowing, proximal part not much dilated due to infiltration of oesophageal wall Dysphagia

21. Ultrasound Principle – a transducer placed on skin produces high frequency sound waves which are reflected back by body tissues – picked up by same transducer to convert into image – displayed on monitor High frequency probe – for superficial lesions Low frequency probe – for deeper lesions Diff b/w solid and cystic swellings Diff b/w benign and malignant swellings FNAC/biopsy

22. Computerised Tomography (CT Scan) Bone anatomy 2 D image But costly and unavailable CT PNS – for rhinosinusitis and tumours Coronal plane – preferred to see osteomeatal relationships – concha bullosa , onodi cells, haller cells, uncinate process Axial view – in children and debilitated patients where coronal view not possible, to see the position of ICA and optic nerve

23. CT Larynx Staging of tumour, laryngeal injury, respiratory obstruction CECT – vascular lesions Spiral CT – fast scan time, reduced patient dose HRCT – High Resolution/ thin section Use of thinly collimated CT sections 1-2 mm thickness mainly for temporal bone fractures and facial nerve course in temporal bone

24. CT Temporal bone Both axial and coronal planes To study ossicles , mastoid, IAC, tegmen , facial nerve, lesions of cerebello ponitine angle, cholesteatoma , fracture temporal bone High resolution CT

25. Magnetic Resonance Imaging (MRI) Soft tissue study MRI machines operates at magnetic strength of 0.5-2 tesla No exposure to ionizing radiations Uses radiowaves 3D image Can demonstrate arteries and veins Costly, time consuming Contraindicated in pregnancy, with metallic implants, pacemakers

26. MRI PNS – mainly for malignancy, mucocele , encaphalocele , intracranial complications MRI temporal bone – tumours, facial canal, intracranial complications MRI larynx – tumours Acoustic neuroma Angiography

27. Radionuclide imaging IV administration of radionuclide Technetium 99m – warthin’s tumour, oncocytoma I 123 – thyroid nodule PET Scan – Positron Emission Tomography Newer radioisotope scan, uses positron emitting isotope injected IV Patient kept nil orally before scan To differentiate between benign and malignant tumours