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Radiology > Neuroradiology: Head and Brain Imagin > Flashcards

Neuroradiology: Head and Brain Imagin Flashcards

1
Q

lacunar infarct (lacune)

A
  • small cerebral infarcts.
  • areas of hypoattenuation (low density), favors basal ganglia, pons, internal capsule
  • common with HTN, atherosclerosis, DM
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2
Q

epidural hematoma

A
  • hemorrhage between the dura and skull table
  • lens shape, biconvex
  • hyperattenuation
  • midline shift common
  • skull fractures common
  • does not cross suture lines
  • ARTERIAL
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3
Q

stroke - considerations

A
  • initial study = CT noncon
  • is it hemorrhagic or ischemic?
  • <6hrs sxs, CT often falsely negative if ischemic
  • MRI more sensitive early on if ischemic
  • types of CVA: hemorrhagic, ischemic, lacunar infarcts
  • if hemorrhagic, keep pt stable and call neurosurgery
  • if ischemic, call neurologist and see if we can fix
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4
Q

Imaging for a suspected stroke

A
  • if the stroke score is very high, you run noncon CT first and then you push contrast and get CTA (angiogram) of head and neck
  • contrast makes everything look white and blood is white - you dont want to confuse ischemic from hemorrhagic - THIS IS WHY YOU GET NONCON FIRST
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5
Q

subdural hematoma

A
  • Hemorrhage between dura and anarchnoid
  • Bridging vein damage
  • Crescent shaped, concave
  • Acute: hyperattenuation
  • Chronic: less dense, hypoattenuation
  • Midline shift common
  • Does not cross midline
  • May cross suture lines
  • VENOUS
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6
Q

CT Head/Brain

A
  • axial cuts and bone windows are standard
  • pathology: symmetry, densities, lucencies, blood (new, old, hemorrhage), ischemia, infarction, edema, tumors, mets, hydrocephalus, bony windows (skull fractures)
  • it is standard and customary to only get axial slices of the brain
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7
Q

Special hydrocephalus

A
  • normal pressure hydrocephalus (communicating type) - classic presentation = >50yo, gait disturbance, dementia, urinary incontinence
  • dilated ventricles out of proportion to atrophy, sulci normal

-THIS CAN BE FIXED

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8
Q

subdural - avute vs. subacute

A
  • acute blood is white
  • subacute - after about 1 week - blood is more isodense
  • chronic - after about 2 weeks - blood alppears hypodense
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9
Q

Approach to head CT interpretation

A
  • check name, date, study, rotation (contrast?)
  • check symmetry (midline shift, effacement)
  • hyperattenuation (acute bleed, calcifications, FBs)
  • hypoattenuation (edema, ischemia, old blood, tumor, air)
  • cisterns, CSF spaces
  • ventricle size, symmetry
  • gyri, sulci symmetric, edema, atrophy
  • soft tissue, sinuses, mastoids
  • bone windows
  • always interpret with attending physician, confirm with radiologist
  • Blood Can Be Very Bad (blood, cisterns, brain, ventricles, bone)
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10
Q

Cerebral edema

A
  • Effacement of gyri and sulci
  • Loss of grey-white differentiation
  • Ventricular compression
  • Global or local response
  • Herniation may result
  • Increased intracraininal pressure:
  • Headache, vomiting, papilledema, possibly ALOC

-Psuedotumor Cerebri (BIH), trauma, infection, tox, metabolic

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11
Q

CT white things with IV contrast

A
  • abnormal = blood, tumor/mass/infection

- normal = vasculature, choroid plexus, pituitary

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12
Q

How CTs are taken

A
  • 15-20 degree axial “cuts”
  • 3mm-5mm wide
  • skull base to vertes
  • scout film
  • grey matter appears grey
  • white matter appears darker
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13
Q

Hydrocephalus

A

-dilated ventricles, temporal horns visible

Obstructive hydrocephalus: 2 types

  • communicating - extraventricular cause (decreased reabsorption of CSF, acute/chronic, entire ventricular system, normal pressure hydrocephalus; 4TH VENTRICLE ENLARGED)
  • non-communicating - intraventricular cause (obstruction of outflowof CSF - tumor, mass; narrow site - 3rd or 4th ventricle, foramena of monroe, aqueduct sylvius; 4TH VENTRICLE NORMAL SIZED, SULCI NORMAL)

-prominent temporal horns of the lateral ventricles is one of the first signs of hydrocephalus

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14
Q

Tumors, masses on CT

A
  • tumors: intraaxial = w/in brain parenchyma (glioma, astrocytoma, etc.), extraaxial = outside of brain itself (meningioma, acoustic neuroma), metastases (round, multiple, enhance w/ contrast)
  • masses (parasites, fungal)
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15
Q

indications for non-contrast head CT

A
  • head trauma - clinically significant
  • suspected acute CVA/TIA, focal neuro deficit
  • HA - atypical worst of life
  • delirium (if there is an obvious cause, CT may not be needed)
  • HA + fever: meningitis/abscess/encephalitis
  • seizure - first one
  • cancer hx with new HA, ALOC, focal neuro finding
  • consider in: vomiting w/o abdominal sxs, suspected child abuse
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16
Q

Cytotoxic cerebral edema

A
  • hypoattenuation from encephalomalacia
  • cell death after cerebral ischemia (infarct)
  • possible midline shift, herniation
  • affects both white and grey matter
17
Q

Increased Intracranial Pressure

A
  • Mass effect - midline shift; From blood or space occupying lesion
  • Cerebral edema - Increase in brain volume (swelling) (May lose normal definition of gyri/sulci, Infection, reactive, malignancy, toxic, anoxic), Vasogenic, Cytotoxic
  • Hydrocephalus - Increase in ventricle size
18
Q

Vasogenic Cerebral edema

A
  • hypoattenuation
  • local edema around infection, malignancy
  • vasogenic edema around acute hemorrhage
  • possible midline shift, herniation
  • predominantly affects white matter
  • INTRACEREBRAL BLEED, not subdural, epidural, subarachnoid
19
Q

subtle CVA signs

A
  • hyperdense vessel sign
  • loss of insular ribbon - grey matter stripe or interface with white matter
  • lentiform nucleus and caudate nucleus not distinctly visible
  • effacement of sulci
  • dont need to recognize on CT, but know the list of signs
20
Q

Plain x-rays - skull

A
  • Rarely obtained - replaced by CT
  • AP, Lateral(s), Towne views standard
  • Indications: Child abuse survey, Foreign Body, Metastatic or Metabolic bone survey, If CT not available
21
Q

indications for contrast CT

A
  • with IV contrast = “contrast enhanced”
  • CVA - non-contrast first in all, then if a significant deficit: CTA (CT angiogram of head and neck, CTA useful for intervention (stent))
  • vascular lesions (AVM, aneurysm)
  • tumors
  • brain abscess, encephalitis
  • MRI now often utilized in these conditions (except CVA)
22
Q

CT white things without IV contrast

A
  • abnormal = blood (acute), calcified masses (i.e. tumor)

- normal = bone, TYPICAL calcifications (pineal gland, choroid plexus, falx, basal ganglia)

23
Q

hemorrhagic CVA

A
  • acute: hyperattenuation: collections of blood
  • favor basal ganglia, thalamus, pons, cerebellum
  • local vasogenic edema
  • effacement of gyri/sulci and midline shift common
  • risks: HTN, coagulopathy, stimulants (cocaine, meth)
  • less common than ischemic; more morbidity/mortality
  • call a neurosurgeon
24
Q

neurocysticercosis

A
  • pork tapework parasite, common in mexico, latin americ

- often asymptomatic, often presents with first seizure

25
Q

how do you know cerebral atrophy is not chronic subdural hemorrhage?

A

-IT CROSSES THE MIDLINE!!

26
Q

CT dark things

A

-abnormal = air, edema, ischemia, encephalomalacia

27
Q

Cerebral atrophy

A
  • diffuse prominence of sulci, ventricles
  • space between edges of brain and skull table
  • normal CSF production, absorption
  • incidental finding, chronic, normal changes with aging
  • dementia (alzheimer’s) alcoholism (cerebellar)
28
Q

MRI of the brain

A
  • excellent for CVA, tumor, patchy neuro deficits
  • more sensitive than CT for cerebellar lesions, central vertigo, multiple sclerosis, diffuse axonal injury, tumors
  • multi plane projections - you get axial, coronal, sagittal (weighting: T1, T2; contrast = gadolinium)
  • no ionizing radiation
  • radiologist reads ALL
  • VERTIGO = MRI!! looking for MS or tumors
29
Q

Subarachnoid hemorrhage

A
  • Hyperattenuation (non-con CT scan)
  • Suprasellar cisterns (Circle of Willis) or other basilar cisterns
  • Sulci white, effacement
  • “Worst HA of my life”
  • Aneurysm, AV malform tumors, trauma
30
Q

traumatic intracerebral hematoma, hemorrhage

A
  • Coup, contrecoup (brain rocks back and forth, boxing); bridging veins are at high risk for hemorrhage
  • Areas of hyperattenuation in brain parynchema
  • Edema surronding blood common
  • Shift, intraventricular blood also possible
31
Q

Indications for CT in HA

A
  • Focal neuro findings + HA
  • ALOC + HA
  • Fever + HA
  • Vomiting (atypical) + HA
  • HA + vomiting after head trauma
  • Severe, persistent, new HA
  • Headache in young, obese female with vision changes, n/v: BIH/Pseudotumor
  • “Worst HA of my life”
32
Q

ischemic CVA

A
  • thromboembolic event
  • vascular watershed distribution of ischemia
  • cytotoxic edema
  • CT often initially negative if <6 hrs sxs
  • hypoattnuation in 12-24hrs on CT
  • low attenuation >4wks
  • big CVA? Get CTA head and neck
  • call neurologist
  • if you dont see anything on CT in first 6 hrs, its ischemic!
33
Q

Pterion

A
  • intersection of the frontal, parietal, temporal and sphenoid bones.
  • thinnest part of the skull
  • middle meningeal artery courses through this area
  • trauma here may cause epidural hematoma
34
Q

CT in head trauma, looking for, and indications

A
  • head trauma: CT noncon first, readily available, great for acute intracranial bleeding, great for fractures, pt must be stabilized
  • looking for: subdural hematoma, epidural hematoma, intracerebral hemorrhage, cerebral contusion
  • indications: focal neuro finding, GCS <8, loss of consciousness, altered level of consciousness, skull penetration, worsening HA, vomiting after head trauma, post-traumatic seizure, suspected child abuse, coagulopathy + trauma, significant mechanism

Radiology (4 decks)

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