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Pathology > Week 14: Neurovascular System Pathologies > Flashcards

Week 14: Neurovascular System Pathologies Flashcards

1
Q

Hyperdense

A
  • more dense, increased density
  • an abnormality on CT that is more dense than surrounding structures
  • bright white on CT image
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2
Q

Isodense

A
  • the same density
  • an abnormality on CT that is the same density as surrounding structures
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3
Q

Hypodense

A
  • less dense, decreased density
  • an abnormality on CT that is less dense than surrounding structures
  • dark, black on CT images
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3
Q

Homogenous

A

consisting of elements that are the same throughout

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4
Q

Heterogenous (non-homogenous)

A

consisting of elements that are not the same throughout

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5
Q

Meningitis

A
  • acute inflammation of the Pia mater and arachnid, two membranes covering the brain and spinal cord
  • comes from infection of the middle ear, frontal sinus, respiratory system, bloodstream or other site
  • two types: bacterial (pyogenic) which is more common and viral, needs spinal tap to determine which one caused the meningitis
  • complications: vasculitis, thrombosis, infarction, hydrocephalus, subdural effusion, emphysema, brain abscess
  • damage to blood vessels can result in gangrene and need for limb amputations
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6
Q

Meningitis Imaging Appearance

A
  • CT and MRI
  • MRI with contrast: most sensitive for 2 innermost meningeal layers (Pia mater and arachnoid membrane)
  • initially, vascular congestion, edema, and minute hemorrhages from inflammation
  • often normal during acute phase
  • may show enhancement of basal cisterns, inter hemispheric fissure and choroid plexus
  • brain swelling may collapse lateral and third ventricles in more advanced cases
  • the imaging signs include brain shift and lateral shift of midline structures, obliteration or dilatation of the ventricles and thinning and obliteration of CSF spaces (sulci, sylvian fissures, basal cisterns)
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7
Q

Glioma

A
  • most common primary malignant brain tumour
  • consists of glial cells (supporting connective tissues in the CNS) which retain ability to multiply
  • most common types: glioblastoma, astrocytoma
  • spread through direct extension
  • can cross from one cerebral hemisphere to the other via corpus callous or other white matter
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7
Q

Glioma Radiographic Appearance

A
  • MRI preferred
  • CT (non-enhanced): a single heterogeneous mass
  • CT (contrast enhanced): a homogeneous lesion with an irregular ring of enhancement
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8
Q

Meningioma

A
  • benign tumour that arises from arachnoid lining cells and is attached to the dura
    radiographic appearance:
  • MRI
  • CT (head): rounded, sharply delineated, hyperdense or isodense tumour abutting dural surface
  • may contain calcification
  • CT (spine): demonstrates location of spinal meningioma mass as a filling defect
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9
Q

Brian Metastases

A
  • usually from lung cancer or breast cancer
  • usually through hematogenous (through blood) spread, may be direct invasion
    radiographic appearance:
  • MRI
  • CT (non-enhanced): lesions that can be hypodense, isodense or hyperdense
  • CT (contrast enhanced): multiple enhancing lesions of various sizes
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10
Q

Indications for Radiographic Imaging in Head Trauma

A
  • CT head scans have mainly replaced general radiography for head injuries but both are still over used
    imaging recommended when:
    1. unexplained focal neurologic signs
    2. unconsciousness (including the unarousable alcoholic)
    3. documented decreasing level of consciousness or progressive mental deterioration
    4. history of previous craniotomy with shunt tube in place
    5. skull depression or subcutaneous foreign body palpable or identified by a probe through a laceration or puncture wound
    6. hemotympanum or fluid discharge from ear
    7. discharge of CSF from the nose
    8. ecchymosis (bruising) over the mastoid process (Battle sign)
    9. bilateral orbital ecchymoses (racoon eyes)
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11
Q

Concussion

A
  • traumatic brain injury that can cause lasting effects on Brian tissue and change the chemical balance of the brain
  • may cause physical, cognitive and behavioural symptoms and problems both long term and short term
  • often include multiple areas of the brain = widespread
  • may co-exist with contusion
  • may be caused by contrecoup injury
  • caused by some kind of head trauma
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12
Q

Concussion Radiographic Appearance

A
  • injury on microscopic cellular level, usually CT imaging normal
  • may show on MRI
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13
Q

Contusion

A
  • brain contusion = bruise injury to brain tissue (commonly frontal and anterior lobe) caused by movement of there brain within the skull after blunt trauma
  • may affect on area of the brain (focal, localized trauma)
  • limited area of damage, but damage often more severe
  • may be other cause than head trauma
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14
Q

Contusion Radiographic Appearance

A
  • CT: low density ares of edema and tissue necrosis demonstrating multiple areas of hemorrhage
  • usually frontal and anterior temporal regions
  • may enhance for several weeks after a contrast injection because of breakdown of BBB
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15
Q

Contrecoup Brain Injury

A
  • injury to brain occurring on opposite side from actual trauma
  • French for counterblow
  • blunt trauma
  • can cause fracture, contusion, concussion
  • radiographic appearance: it depends on if fracture, contusion, concussion etc
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16
Q

Normal Aging

A
  • gradual loss of neurone results in enlargement of the ventricular system and sulci
  • difference between normal aging, dementia and Alzheimer’s dementia is the degree of impairment and the rate of decline
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17
Q

Alzheimers Disease

A
  • presentile dementia
  • diffuse form of progressive cerebral atrophy that develops at an earlier age that the senile period
  • causes difficulties in day to day functioning and memory of familiar people
  • radiographic appearance: CT/MRI: cerebral atrophy with enlarged ventricles and prominent cortical sulci
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18
Q

Parkinson’s Disease

A
  • shaky palsy
  • progressive degenerative disease
  • changes in nerve cells occur in the basal ganglia
  • enzyme defect that results in an inadequate production of the neuronal transmitter substance dopamine
  • involuntary tremor of limbs when holding still
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19
Q

Parkinson’s Disease Radiographic Appearance

A
  • CT: appearance of cortical atrophy similar to that of normal aging process
  • SPECT and PET: can be used to determine cellular function
20
Q

Hydrocephalus

A
  • dilation of the ventricular system usually associated with increased intracranial pressure
  • usually due to an obstruction causing cranium enlargement in infants due to lack of complete skull bone fusion
21
Q

Hydrocephalus Shunt

A
  • insertion of a shunt between the dilated ventricles and the heart or peritoneal cavity
  • fluid flows away from the brain ventricle
  • decreases intracranial pressure and ventricular size
  • if left untreated, compresses brain and can cause brain damage
22
Q

Hydrocephaly Radiographic Appearance

A
  • CT demonstrates ventricular dilation
  • low dose CT used for monitoring
  • xray imaging used for shunt patency check
23
Q

Brain Bleeds

A
  • when head injury and or potential bleed suspected, perform a non-contrast head CT first, then contrast can be used if needed
  • contrast will mask bleeds, especially small ones, because bleeds and contrast are both hyperdense, and both show up white in the image
  • bring brain bleeds to radiologist’s attention right away
24
Q

Cerebral (Intracranial) Hemorrhages/ 
Hematomas

A
  • collection of blood in the head/brain
  • can occur with head injury, even if external injury not present/seen
25
Q

Epidural Bleed (Hemorrhage)

A
  • this bleed happens between the skull bone and the outer most membrane layer, the dura mater
  • bleeding within skull, outside of brain
26
Q

Subdural Bleed (Hemorrhage)

A
  • this bleed happens between the dura mater and the arachnoid membrane
  • bleeding within skull, outside of brain
27
Q

Subarachnoid Bleed (Hemorrhage)

A
  • this bleed happens between the arachnoid membrane and the pia mater
  • bleeding within skull, outside of brain
28
Q

Intracerebral Hemorrhage

A
  • this bleeding occurs in the lobes, pons and cerebellum of the Brian (bleeding anywhere within the brain tissue itself including the brainstem)
  • bleeding inside brain tissue
29
Q

Intraventricular Hemorrhage

A
  • this bleeding occurs in the brains ventricles, which are specific areas of the brain (cavities) where CSF is produced
  • bleeding inside brain tissue
30
Q

Blood Condition and Density

A
  • acute blood is bright white on CT (once it clots)
  • blood become isodense at approx. 1 week
  • blood become hypodense at approx. 2 weeks
  • unclotted, fresh blood is isodense or hypodense
31
Q

Epidural 
Hematoma/ Hemorrhage

A
  • blood between the skull and dura mater
  • most often a skull fracture present
  • result of trauma, acute arterial bleeding usually caused by laceration of the medial meningeal artery or its branches
  • acute neurological symptoms
  • emergency surgical decompression needs to relieve intracranial pressure
  • radiographic appearance: CT: bidonnes peripheral high-density lesion, showing midline shift. convex/lens shaped, middle meningeal artery (epi=pie=lemon shape)
32
Q

Subdural Hematoma / Hemorrhage

A
  • result of trauma, venous bleeding most commonly from ruptured veins between the dura mater and the meninges (arachnoid) so into subdural space
  • slower bleed (than arterial) with gradual neurologic deficits
  • may take time (days, weeks)
    to develop symptoms
  • can lead to death
33
Q

Subdural Hematoma / Hemorrhage Radiographic Appearance

A
  • CT
  • acute = crescent shaped peripheral high density (hyperdense) lesion
  • isodensity or hypo density within lesion = rapid bleeding and unclothed blood
  • chronic = isodense lesion, demonstrated by ass effect/midline shift
  • concave/crescent shape, bridging veins (suB = banana shape)
34
Q

Intracerebral Hemorrhage/ Hematoma

A
  • traumatic hemorrhage into the brain parenchyma resulting from shearing forces to intraparenchymal arteries usually at the junction of the grey and white matter
  • damage to intima layers which ruptures
35
Q

Intracerebral Hemorrhage/ Hematoma Radiographic Appearance

A
  • CT: well circumscribed, homogenous, high density (hyperdense) region surrounded by low density regions of edema
  • 2-4 weeks post injury become isodense as blood breaks down
36
Q

Intraventricular Hemorrhage

A
  • presence of blood in the ventricles
  • can be secondary to intracerebral hemorrhage
  • radiographic appearance: CT: homogenous, high density (hyperdense) region within ventricles
37
Q

Subarachnoid Hemorrhage from Trauma

A
  • injury to surface veins, cerebral parenchyma or cortical arteries can produce bleeding into the subarachnoid space and ventricles
  • radiographic appearance: CT: increased density within the basal cisterns, cerebral fissures and sulci
38
Q

Cerebrovascular Disease

A
  • refers to any process that is cause by an abnormality of the blood vessels or blood supply to the Brian
  • included in these are strokes, TIAs and aneurysms
39
Q

Subarachnoid Hemorrhage from a Vascular Incident

A
  • major cause of hemorrhage (said form head trauma) is rupture of berry aneurysm in brain
  • most common locations are origins of the posterior cerebral and anterior communication arteries and the trifurcation of the middle cerebral artery
  • radiographic appearance: CT: non-contrast scan initially shows hyper density (blood) in the subarachnoid space
40
Q

Aneurysm

A
  • a localized dilation of an artery that most commonly involves the aorta, especially its abdominal portion
  • due to weakness in wall form decreased elastin and increased collagen production
  • can rupture/burst
  • brain aneurysms that burst can cause hemorrhagic stroke
  • also common in Circle of Willis in the brain
41
Q

Aneurysm Radiographic Appearance:

A
  • CT: vessel bulge, malformation
  • non-contrast scan initial shows hyperdenity (blood) in brain if ruptured
42
Q

Stroke (CVA) 
– Cerebrovascular Accident

A
  • sudden loss of brain function caused by the interruption of flow of blood to the brain (ischemic stroke (blockage) approx. 80%) or the rupture of blood vessels in the brain (hemorrhagic stroke)
  • interruption of blood flow or the rupture of blood vessels causes neurons in the affected area to die (cerebral infarct)
  • effects of a stroke depend on location and severity
  • act fast!
43
Q

Stroke Diagnosis and Treatment

A
  • need immediate head CT evaluation in the acute stroke patient to rule out intracranial hemorrhage [so to differentiate ischemic (intravascular clot/ blockage) from intracranial hemorrhagic stroke (vessel rupture in brain) before treatment]
  • time from occurrence to treatment is critical
  • treatment different depending upon stroke type: fibrinolytic / thrombolytic agents (clot busters) if blockage, clip bleed source and burr hole for blood drainage if bleed
44
Q

Intraparenchymal Hemorrhage/ Intracerebral Hemorrhage/ Hemorrhagic Stroke

A
  • rupture of blood vessel in brain
  • principle cause of hemorrhage (aside from head trauma) is hypertensive vascular disease (high blood pressure)
  • can also be a congenital berry aneurysm or an arteriovenous malformation that bursts
  • ruptured vessel cannot supply blood/oxygen to areas further on, and pooled blood puts pressure on brain
45
Q

Hemorrhagic Stroke Radiographic Appearance

A
  • non enhanced CT
  • new hematoma/ hemorrhage appears as homogeneously hyperdense, well-defined, round or oval lesion with mass effect
  • well circumscribed high density (hyperdense) region often surrounded by low density (hypodense) edema
  • after 3 days = isodense area as blood breaks down
  • after 6 months = smaller hypodense area
46
Q

Ischemic Stroke

A
  • blockage of vessel in brain with subsequent loss of oxygenation beyond blockage and infarct
  • CT exam recommended (or MRI), but no CT contrast for stroke evaluation
  • contrast can cross the disrupted blood brain barrier (BBB) in infarcted area which can lead to increased edema and slower recovery
47
Q

Ischemic Stroke Radiographic Appearance

A
  • non enhanced CT
  • CT – initially appears normal in an ischemic stroke
  • then, after 8-24 hours, as a triangular or wedge shaped area of hypo-density on CT
  • mass effect seen 7-10 days after onset
  • MRI/MRA recommended to show
48
Q

Transient Ischemic Attack (TIA)

A
  • a temporary interruption of blood flow to the brain
  • from small emboli or stenosis, often coming from carotid bifurcation in neck
  • symptoms are similar to an ischemic stroke except they are temporary
  • an important warning sign for increased risk of stroke
  • likely prescribed low dose aspirin
  • radiographic appearance: doppler US of neck for diagnosis

Pathology (14 decks)

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