Neuroradiology

Question 1

• X-Ray
  
  • Uses
  • Pros
  • Cons

Answer 1

• Used for:
  
  • Trauma (fractures)
  • Degenerative disease (RA)
  • Post-op checks
• Pros
  
  • Cheap
  • Fast
• Cons
  
  • Radiation
  • Lack of soft tissue detail

Question 2

• Flouroscopy

Answer 2

• Real time X-Ray
• Used for diagnosis and intervention
  
  • Swallow studies
  • Angiography
  • Myelography
• Uses contrast

Question 3

• Barium Swallow Study
  
  • Used to Evaluate
  • Pros
  • Cons

Answer 3

• Used to evaluate
  
  • Dysphagia
  • Epigastric pain
  • GERD
• Pros
  
  • Live demonstration of swallow coordination
• Cons
  
  • Time consuming
  • Contrast
  • Radiation

Question 4

• Angiography
  
  • Used for
  • Pros
  • Cons

Answer 4

• Used for
  
  • Aneurysms, Vascular malformations, fistulae
  • Vessel stenosis, thrombosis, dissection
  • Stenting, embolization, thrombolysis (mechanical and pharmacological)
• Pros
  
  • Ability to intervene
  • Fast
• Cons
  
  • Invasive
  • Contrast
  • Radiation

Question 5

• Myelography
  
  • Used for
  • Pros
  • Cons

Answer 5

• Used for
  
  • Spinal stenosis, Nerve root compression
  • CSF leak
  • MRI contraindication
• Pros
  
  • Defines subarachnoid space
  • Identifies spinal block
• Cons
  
  • Invasive
  • Complications (CSF leak, headache)
  • Radiation
  • Contrast

Question 6

• Ultrasound
  
  • Used for
  • Pros
  • Cons

Answer 6

• Used for
  
  • Carotid stenosis
  • Infant brain imaging (open fontanelle=acoustic window)
• Pros
  
  • non-invasive, cheap, fast
  • Quantitates blood velocity
• Cons
  
  • Steep learning curve (operator dependent)
  • Limited penetration thru air/bone

Question 7

• CT

Answer 7

• Series of X-rays scanned axially and then digitally re-sliced in any plane
• Radiodensity measured in Hounsfield Units (HU)
• HyperDENSE=white/bright
• HypoDENSE=Black/Dark

Question 8

• Hounsfield units

Answer 8

• Level is the center of the window
• Window is the width of HU in the generated view
• Wider windows compare areas with different HUs
• Narrow windows compare areas with similar HUs

Question 9

• CT
  
  • Used for
  • Pros
  • Cons

Answer 9

• Used for
  
  • Skull, skull base and vertebrae
    
    • Trauma, bone lesions
  • Ventricles
    
    • Hydrocephalus, masses, mass effect
  • Intracranial masses, mass effect
    
    • Nausea, Vomiting, Headache, Visual Symptoms
  • Hemorrhage, Ischemia
    
    • Stroke, mental status change, focal neurological deficits
  • Calcification
    
    • Lesion characterizartion
• Pros
  
  • FAST
  • Cheap
  • Most beneficial for ruling out large pathology (bleed, large ischemic stroke, mass, abscess, hydrocephalus)
• Cons
  
  • Less detail
  • Radiation
  • Low sensitivity in posterior fossa

Question 10

• When is IV contrast NOT indicated

Answer 10

• Trauma
• Rule out hemorrhage
• Hydrocephalus
• Dementia
• Epilepsy
• Rule out acute stroke

Question 11

• When is IV contrast indicated in a CT

Answer 11

• Neoplasm
• Infection
• Vascular disease
• Inflammatory disease
• Symptoms lasting longer than 3 hours

Question 12

• CT contrast is _ based
• MRI contrast is _ based

Answer 12

• CT contrast-iodine based
  
  • Highly attenuating of X-Rays
  • Risk of anaphylaxis or other allergic reactions
• MRI contrast-Gadolinium based
  
  • Paramagnetic metal that increases T1 relazation of nearby water protons (bright on MRI)
  • Risk of nephrogenic systemic fibrosis in patients with renal insufficiency
• Tissure that gets brighter with contrast is said to “enhance”
• Enhancement reflects vascularity of tissue

Question 13

• Contrast

Answer 13

• BBB keeps IV contrast out of brain
• Enhancement in brain parenchyma is indicative that BBB is absent or dysfunctional (tumors, inflammation, infarction)
• Structures that will enhance IV contrast (outside BBB)
  
  • Cerebral blood vessels
  • Meninges
  • Pineal gland
  • Pituitary gland
  • Choroid plexus

Question 14

• CT Angiography
  
  • Used for
  • Pros
  • Cons

Answer 14

• Used for
  
  • Atherosclerosis, thromboembolism
  • Vascular dissection
  • Aneurysms, vascular malformations
  • Penetrating trauma
• Pros
  
  • Non-invasive
  • Cheaper
  • Evaluate vessels from origin to intracranial
• Cons
  
  • Contrast
  • Radiation
  • Lower res compared to MR or Catheter angiography (fluoroscopy)

Question 15

• Contrast study v angiogram

Answer 15

• Contrast
  
  • Used to evaluate breakdown in BBB and identify abnormal brain parenchyma or tissue
• Angiograms
  
  • Used to evaluate blood vessels

Question 16

• MRI
  
  • Used for
  • Pros
  • Cons

Answer 16

• Used for
  
  • Further evaluations of CT findings- better than contrast enhanced CT when evaluating ischemia)
  • Chronic/Subacute symptoms
  • Tumors/Masses
  • Infection (Abscess, meningitis, encephalitis)
• Pros
  
  • More detail
  • Safe in pregnancy
  • Can obtain vessel imaging without contrast
• Cons
  
  • Slower
  • More contraindications (metal, implantable devices, cardiac pacemakers, aneurysm clips, bullet fragments)
  • Expensive
  • Patient must hold still

Question 17

• T1

Answer 17

• CSF-Dark
• White matter-bright (hyperintense)
• Good image for identifying anatomy

Question 18

• T2

Answer 18

• CSF-Bright (hyperintensive)
• White matter-Dark (hypointensive)

Question 19

• T2 Flair

Answer 19

• Removes CSF from T2 image
• Enhances fluid with increased protein content
• Great for visualizing edema/abscesses
• Dying neurons will swell as their Na+/K+ pumps stop working and H2O accumulates inside of the cell
• FLAIR-Fluid Attenuated Inversion Recovery