Thyroid Cancer Thyroid Cancer Definition A malignant tumour arising from the thyroid or parafollicular C cells ▸ it is an uncommon tumour (accounting for 0.5% of all cancer deaths) Risk factors: previous radiation exposure ▸ iodine excess ▸ a genetic…
Mandibular/Maxillary Cystic Lesions General Features Definition Cysts occur more frequently within the jaw than in any other bone due to the numerous epithelial cell residues left after tooth formation ▸ these cysts are slow growing and painless (unless they become…
Selected Disorders of the Ear External Ear Squamous or basal cell carcinoma HRCT Defines the extent of any bone erosion or destruction MRI Allows precise assessment of the soft tissue mass Necrotizing otitis externa Definition An osteomyelitis/necrosis particularly affecting the…
The Orbit Definition Disease processes can be classified according to the anatomical site involved – this is usually in relation to the rectus muscle pyramid (the ‘cone’) Intraconal (within the muscle cone) Optic nerve glioma Optic nerve meningioma Haemangioma Inflammatory…
Spinal Dysraphism Spinal Dysraphism Definition This is also known as a neural tube defect (NTD), and are a group of congenital spine abnormalities that may cause progressive neurological damage (affecting 1 : 1000 live births) The common feature is an anomaly of…
Cerebellar Malformations Cerebellar Hypoplasia Definition The cerebellum may be small due to a congenital lack of formation or from subsequent atrophy ■ Causes: infection (especially congenital cytomegalovirus) ▸ inborn errors of metabolism (e.g. glycolysation disorder) ■ Other rarer causes: carbohydrate-deficient…
Head Injury Subdural Haemorrhage (SDH) Definition Traumatic bleeding between the dura mater and arachnoid mater ▸ it usually arises from rupture of the veins crossing the subdural space (vault fractures are an uncommon cause) ▸ often associated with brain damage…
Intracranial Infection Brain Abscess Definition A focal encapsulated pus-containing cavity ▸ in immunocompetent patients it is usually due to a streptococcal bacterial infection (multiple in 10–50%) ▪ It usually arises by haematogenous dissemination ▸ it can also occur following penetrating…
Cerebral Ischaemia Cerebral Ischaemia Definition Stroke A sudden persistent neurological deficit of vascular origin Causes Large vessel thromboembolic stroke (40%) Most commonly due to thrombus at the site of atherosclerotic plaque or embolization more distally ▸ sites: carotid bifurcation >…
Imaging Techniques and General Features Computed Tomography NECT Intra-axial tumours: usually of low attenuation on NECT ▸ high attenuation areas within a tumour indicate tumour calcification or recent intratumoural haemorrhage Extra-axial tumours: associated with bone erosion or hyperostosis CECT Improved…