Diagnostic radiology: neuroradiology Flashcards
What is the density of blood, fat, soft tissue and calcium in CT scan?
How can you tell the difference between T1 and T2 weighted MRI via CSF, spinal cord and muscle?
What are pros and cons of MRI for radiation, cost, duration, bone assessment, soft tissue assessment, incompatible devices
What IV contrast is used for CT and MRI?
CT: iodine
MRI: gadolinium
What imaging can be used for aneurysms, vascular malformations, large vessel arterial occlusion, stenosis or dissection?
CT/MR angiogram
What imaging can be used for dural venous sinus thrombosis?
CT/MR cerebral venogram
What imaging can be used for planning of neuroendovascular treatment?
Digital subtraction angiography which is more invasive
What imaging used for extra-cranial carotid stenosis?
Doppler USG
What imaging would be used to detect IVH in preterm infants and what condition does it have to meet?
Ultrasound infant brain
Only possible if fontanelles are still wide open
What are advanced neuroimaging?
CT perfusion
MR perfusion
MR spectroscopy
Diffusion tensor imaging
Functional MRI
Weigh the pros and cons of plain radiograph, CT and MRI for radiation, cost, duration, bone assessmentm soft tissue assessment and other non radiation related contraindications
What imaging used for spinal trauma?
- Plain radiographs
- Plain CT
‒ High sensitivity and specificity - Plain MRI
− ligamentous, spinal cord and soft tissue injuries
− neurological deficits not explained by plain film or CT
What imaging used for spinal cord compression and the possible clinical presentation?
- Clinical presentation
− Motor deficit, sensory level, incontinence +/- urinary retention - Plain radiographs / CT
− Collapse, destructive bone lesions, retropulsion - MRI
− Allows visualization of the cord
What are the indications for imaging in head injury?
Low GCS, skull fracture, seizure, focal neurological deficit, multiple vomiting, retrograde amnesia
Clotting disorder, anticoagulation
High energy trauma
Infants with large scalp soft tissue injury, suspected non accidental injury, tense fontanelle
What is 1st line imaging for head injury?
Plain CT brain to visualize hemorrhage and skull fractures
Skull radiograph not beneficial as cannot exclude intracranial hemorrhage and can only detect fractures
What is 1st line imaging for seizures?
What other imaging may be considered?
Plain CT brain in acute/emergency settings
Detect hemorrhage or calcific lesion
Contrast CT brain if suspecting intracranial infection, tumor, inflammatory lesion, vascular pathology
MRI: sensitive to subtle lesions e.g. malformations
+ contrast if suspecting intracranial infection, tumor, inflammatory lesion, vascular pathology
What are advanced imaging techniques used for seizures?
Pre-operative planning: SPECT, FDG PET/CT, functional MRI
What are the indications for skull imaging in acute headache?
Thunderclap headache
Redflag signs: new onset, history of cancer or immunodeficiency, clotting problem, anticoagulation, associated mental state change, meningitis features, focal neurology and progressive deterioration
What is 1st line imaging used for acute headache when there is indication?
Plain CT brain to visualize blood, space occupying lesion
What is the imaging done for acute stroke?
Plain CT brain to delineate extent and location, exclude hemorrhage before thrombolytic or antiplatelet therapy
Intra-arterial thrombectomy: selected cases within therapeutic time window
CT cerebral angiogram for planning
MRI brain
DWI: more sensitive than CT in acute stroke
Perfusion MRI for salvageable brain tissue
Long scanning time and waiting time limits role of MRI in acute setting
When is IV contrast indicated in acute setting?
Plain CT is the imaging of choice in most acute settings
IV contrast for abscess, metastases/tumor, venous sinus thrombosis, CT angiogram
What is intra-axial, extra-axial and interventricular?
Intra-axial: within brain parenchyma
Extra-axial: inside skull outside brain parenchyma
Intra-ventricular: within the ventricular system
What are the 2 signs below?
Intraaxial or extra-axial?
Extracranial: Meningioma
Intra-axial or extra-axial?
Epidural vs subdural haematoma?
What vessels involved, shape, cross suture, cross midline, clinical course and associated bone fracture?
What is the subdural space and its significance in subdural haematoma?
Subdural space = potential space between the dura and arachnoid mater of the meninges around the brain
Subdural hematoma → across sutures
What is the epidural space and its significance in epidural haematoma?
Epidural space = between inner surface of the skull and outer layer of the dura, outer dural layer functions as periosteum of inner calvarium Epidural hematoma is subperiosteal hematoma → cannot cross sutures
7yo kid whats seen?
Hyperdense bi convex/lentiform collection (epidural haematoma)
Bone window: overlying skull fracture
Scalp haematoma
Extra-axial (outside brain parenchyma)
Hyperdensity in the the basal cisterns (surrounding brainstem)
Subarachnoid hemorrhage
What is the subarachnoid space?
–Basal cisterns, suprasellar cistern, sulcal spaces, Sylvian fissure–Communicate with ventricles
*Look for intraventricular haemorrhage
Hyperdense thickening of bilateral interhemispheric falx
*Imaging appearance:
–crescent-shaped hyperdense extra-axial
–can cross sutures
Acute subdural hemorrhage
M/48 left hemiplegia and left CN7 palsy
Acute right putaminal haematoma due to hypertensive intracerebral hemorrhage (deep grey matter)
4th ventricle compressed: hydrocephalus
How to differentiate between cererbal atrophy and hydrocephalus?
Hydrocephalus: lateral ventricles are dilated out of proportion to sulcal spaces
70/M sudden onset of dysphasia
Loss of grey white differentiation
Wedge shaped hypodensity
Swelling in right frontal lobe
Ischemic event
right hyperdense MCA sign
What are the risk factors of hemorrhagic transformation of ischemic infarct?
–Older age–Larger stroke size–Cardioembolicstroke–Anticoagulation–Elevated systolic blood pressure in acute setting–Thrombolytic therapy –Delayed recanalisationtherapy
Vasogenic edema at right parietal region, causing mass effect leading to midline shift
Extend to posterior limb of internal capsule
Maintained grey white matter differentiation
Edema involves mainly white matter
T1W: fluid dark
T2W and T1W FS post-contrast: Enhancing irregular ill-defined mass with surrounding oedema Excision: Glioblastoma multiforme
Lung adeno patient
Lung CA patient presenting with headache
Left temporal lobe, left cerebellar lobe
Peripheral cerebral edema
Left tonsillar herniation through foramen magnum to compress on brainstem (coning) = surgical emergency
What is CT appearance of intracranial hemorrhage acute, subacute and chronic?
