1. The brain is ___ % of total body weight.
    2 %
  2. The brain consumes ___ % of the body's oxygen supply.
    20 %
  3. PCoA connects into the ___ from the PCA.
  4. ECA characteristics:
    • "Flashy" color
    • Smaller
    • Extracranial branches
    • High resistance
    • Anterior Medial orientation
  5. ICA characteristics:
    • Consistant color
    • Larger
    • NO extracranial branches
    • Low resistance
    • Posterior Lateral orientation
  6. Intimal Thickening:
    • Process that goes on with age.
    • Small particles of plaque are deposited within intima that causes thickening.
    • Intimal reflection will get thicker. (Measure intimal thickness).
    • Intima is removed with a CEA. (Plaque is peeled away from wall but, the intima is also removed.
  7. Fibromuscular Hyperplasia:
    • Can be seen after CEA.
    • The media accumulates smooth muscle cells to replace the intima that was stripped away during a CEA.(After 2 years).
    • AKA - Myointimal Hyperplasia (Post CEA name).
  8. Fibromuscular Dysplasia:
    • "String of pearls"
    • Media has an abnormal growth of smooth muscle cells.(Seen in older women and Asian decent).
  9. Plaque:
    • Migration of smooth muscle cells under sub endothelial layer.
    • Lipid materials accumulate.
    • Fibrous cap.
    • Plaque formation.
  10. 2 Types of Plaque:
    • Uncomplicated:
    • Uniform between intima and media.

    • Complicated:
    • Edges.
    • Fibrous cap becomes irregular.
  11. Ulcers:
    Can cause blood clots to form ______.
    Complex lesions, which cause more problems.
    • Embolus.
    • Hemorrhaging - bleeding of capillaries can rupture through the lipid core, more thrombus now can develop on fibrous cap and decrease lumen size.
  12. Characteristics of Plaque:
    • Anechoic
    • Homogenous:  Same texture throughout.
    • Heterogenous: Different mixtures of stuff in plaque.
    • Focal plaque: Localized in one area some can be very thin.
    • Diffuse plaque: Spread over a large area.
    • More complicate plaque is... Ulcerations.
  13. Common Causes of Stroke:
    • Atherosclerosis 
    • Emboli: (could be from heart--A FIB) 
    • Hypertension: Vessel walls can rupture.
    • Dissection
    • Prethrombotic states: Clotting disorders.
    • Vasospasm: Subarachnoid hemorrhage.
  14. Transcient Ischemic Attack (TIA):
    • Lasts less than 24 hours. (Only lasts a few minutes).
    • If an individual experiences a TIA, most people will go through a full blown CVA.
  15. Reversible Ischemic Neurological Deficient (RIND):
    • Lasts longer than 24 hours, but returns back to normal.
    • Neurological deficit resolves in approximately 3 weeks.
  16. Cerebral Vascular Accident (CVA):
    • Lasts longer than 24 hours.
    • Permanent neurological damage.
    • 3rd leading cause of death.
  17. Anterior Circulation Symptoms:
    • Unilateral - parethesia, paresis, paralysis
    • Aphasias, arm paralysis, or paresis usually means disease in MCA).
    • (Leg paralysis, incontinence usually means disease in ACA.)
  18. Posterior Circulation Symptoms:
            Vert. A/Basilar A/PCA
    • Bilateral - paralysis
    • (Double vision, vertigo, ataxia, drop attacks)
    • Coma or dyslexia might indicate disease in PCA.
  19. Non-localized symptoms:
    • Dizziness
    • Syncope
    • Headache
  20. ICA Stenosis Criterias:
    • A stenosis of 50-79% has a PSV of >120 cm/s. 
    • Hemodynamically significant.
    • Marked spectral Broadening. (Increase in PEDV).
  21. ICA Stenosis Criterias:
    • ICA Occlusion doesn't have a velocity, because there is no flow.
    • CCA waveform is now high resistance.
  22. Lacunar Strokes:
    • Risk of stroke and death is higher in patients.
    • Leukoaraiosis: scattered loss of white matter in the brain. (Associated with strokes caused by blockages in small arteries deep in the brain).
  23. Poiseuillle's Law
    • Flow rate; volume flow occurs primarily because of energy gradients, but observed as pressure gradient. 
    • An energy gradient must exist for flow to occur.
    • Flow moves from the area of higher pressure to the area of lower pressure; the greater the pressure gradient, the greater the flow rate.
  24. Poiseuille's Law explains the interrelationship among:
    • Pressure
    • Viscosity
    • Flow
  25. Poiseuille's Law:
    Refer to notes.
  26. Resistance equation:
    Refer to notes.
  27. Diameter Reduction:
    A/B X 100 = Y

    • Y is the size of the remaining lumen expressed as a percentage of the original lumen.
    • 100 - Y = YS, the size of the stenosis expressed as a percentage of the original lumen.

    (Refer to notes).
  28. Area Reduction:
    (A/B)² X 100 = Y

    • Y is the size of the remaining lumen expressed as a percentage of the original lumen.
    • 100 - Y = YS, the size of the stenosis expressed as a percentage of the original lumen.

    (Refer to notes).
  29. If the radius is decrease...
    Resistance _______
    Pressure Gradient _______
    Both increase.
  30. Reduction:

    When the obstruction reduces the diameter of the vessel by:
    Diameter Reduction      Area Reduction
               30%           --->         ?
               50%           --->         ?
               70%           --->         ?
    • 30% --- 50%
    • 50% --- 75%
    • 70% --- 90%
  31. Estimating Reduction:
    • B-mode imaging is the most appropriate method to evaluate the degree of narrowing.
    • 1st - Transverse
  32. Carotid Stenosis Criteria Chart:
    Refer to notes.
  33. Why do we calculate ICA and CCA ratios?
    • Presence of tandem lesions.
    • Contralateral high grade stenosis.
    • Discrepancy between visual assessment of plaque and ICA PSV.
    • Elevated CCA velocities.
    • Hyper dynamic cardiac states.
    • Person may have poor CO, therefore have a decreased CCA velocity.
  34. Ratio Example:

    Use Distal CCA
    PSV for ICA is 90 cm/s
    PSV for Distal CCA is 125 cm/s
    EDV for ICA is 40 cm/s
    EDV for Distal CCA is 60 cm/s
    • ICA/CCA PSV Ratio: 0.72
    • ICA/CCA EDV Ratio: 0.66
  35. Ratio Example:

    PSV for Distal CCA is 175 cm/s
    PSV for ICA is 130 cm/s
    EDV for ICA is 40 cm/s
    EDV for Dist CCA is 80 cm/s
    • ICA/CCA PSV Ratio: 0.74
    • ICA/CCA EDV Ratio: 0.50
  36. Trials:

    1. NASCET
    2. ACAS
    3. ECST
    • 1. North American Symptomatic Carotid Endarterectomy Trial
    • 2. Asymptomatic Carotid Atherosclerosis Study
    • 3. European Carotid Surgery Trial
  37. Trials:
    These trials have had a profound impact on validating the indications for CEA in patients with carotid bifurcation atherosclerosis.
  38. The NASCET and ECST trials used different methods of reporting the degree of narrowing seen on an Angiogram.
  39. Subclavian Steal Review:
    Occlusion seen in Lt Subclv. A Prox before Vert A take off --- Retrograde flow in Lt Vert A.

    Stenosis seen in Lt Subclv. A Prox before Vert. A take off --- To Fro Flow

    Usually asymptomatic.
  40. Subclavian Steal Review:
    • Difference in blood pressure >20 mmHg.
    • Vertebrobasilar symptoms.
    • Monophonic in Subclv. A
    • Retrograde or To Fro Flow
  41. Cerebral Anatomy:
    _____ is a branch off of the ICA.
    Ophthalmic A
  42. Ophthalmic A has 3 terminating branches:
    • Supraorbital A
    • Frontal A
    • Nasal A (Which turns into Angular A then hooks into Facial A)

    Important anastomosis!!
  43. CW Doppler in Supraorbital A:
    • Normal: Toward flow
    • Abnormal: Away flow
  44. MCA is the dominant out of the MCA and ____.
  45. If you have a MCA occlusion you will notice it in your ____ or ____.
    ICA or CCA

    • (Resistive Spectra Waveform)
    • Snap Snap. 
    • Hammerhead.
  46. Dolichocarotid Arteries:
    • Carotid artery that has an unusual shape.
    • Types:
    • Looped or coiled
    • Kinked
    • Tortuous
    • C-Shaped
    • S-Shaped
  47. Risk Factors:
    • Atherosclerosis
    • History
    • Increased cholesterol
    • Smoking
    • Age
    • Sedentary
    • Hypertension
    • Diabetes
  48. Spectral Waveform:
    • 1. Movement
    • 2. Velocity
    • 3. Turbulence
    • 4. Direction
    • 5. Amplitude
  49. Bernoulli's Principle:
    Pressure in a stenosis decreases and velocity increases.
  50. Carotid Stenting:
    Use as an intervention instead of CEA for patients with a high risk with coronary, pulmonary, or renal diseases.
  51. CEA:
    • Involves exposing the carotid bifurcation and clamping the CCA, ICA, and ECA.
    • Clamping can compromise cerebral circulation and where appropriate, a temporary plastic shunt can be used to maintain flow between the CCA and ICA while the plaque is surgically removed.
    • Vein patches:Can be susceptible to rupture.
    • Prosthetic patches:Can be susceptible to infection.
  52. The brain receives ___% of our CO.
  53. Transcranial Doppler (TCD):
    • Blind Pulsed Wave for intracranial vessels 1st type.
    • Used in the detection of micro embolic (MESs) by means of TCD-count and detect micro emboli circulating through cerebral arteries.
  54. Transcranial Doppler Image (TCDI) or Transcranial Color-Coded Duplex Sonography (TCCS):
    Combines B mode imaging with frequency based color coding and doppler sonography.
  55. Why Use TCD?
    • Intracranial Stenosis: Increase in flow velocity, spectral broadening co-vibration phenomenon.
    • Hemodynamic Effects: Ex. Bruits
    • AVM's- Arterial Venous Malformations: When they are causing cerebral problems.
  56. What is an AVM?
    • Developmental abnormality: arteries and veins involved in supplying blood to the AVM are essentially normal and are the usual arteries supplying the region of the brain where the AVM is located.
    • You can tell it's an AVM by significant flow abnormalities.
    • Increased flow velocities.
    • Reduced pulsatility.
    • Reduced responsiveness to CO²
  57. Why use TCD?
    Intermittent Monitoring
    • Monitoring vasospasm.
    • Subarachnoid Hemorrhage: at least a week of hemorrhage look for cerebral constriction check if meds are controlling.
    • Severe migraines.
    • ICA Occlusion: when administering thrombolytic to dissolve-try to recanalize
    • Anticoagulation
    • Shrink AVM's
  58. Why use TCD?
    Continuous Monitoring
    • While doing an CEA if a shunt is not put in and if one is put in checking to see if cerebral system is okay.
    • Cardiopulmonary bypass on heart-lung machine.
    • Neural surgery
    • Increase ICP-Intracranial pressure.
    • Those with severe cerebrovascular disease.
    • Diagnose brain death- little or no flow.
  59. Why use TCD? 
    Functional Testing
    • Stimulation of vasomotor- How is CO² is affecting cerebral flow.
    • Language lateralization (prior to neurosurgery).
    • Pre-evaluation look at collateral flow in circle of Willis.
    • Stimulation of visual cortex-check for abnormalities.
  60. Pre-TCD Exam
    • 1. Evaluate extra cranial artery status. (Carotid)
    • 2.Have patient resting to avoid PCO² fluctuations.
  61. Transcranial Exam:
    • 1. Cranial windows- Ex: transtemporal, transorbital
    • 2. Insonation- depth
    • 3. Flow direction- Ex: toward or away
    • 4. Spatial relationships- Ex: angle this way (posterior or anterior)
    • 5. Relative flow velocity- evaluate velocity
    • 6. Response to oscillational compression-not used often ...pushing on CCA
  62. Transtemporal
    • Thin
    • Access points within window.
    • Frontal, Anterior, Middle, Posterior

    • Locate most of the arteries:
    • MCA
    • ACA
    • PCA
    • TICA
    • ACoA
  63. Transtemporal Window:
    • MCA: toward (3-6cm)
    • MCA/ACA bifurcation: bidirectional (5.5-6.5cm)
    • ACA: away (6-8cm)
    • TICA: toward
    • PCA: 7.5cm
  64. Transorbital:
    • 15-20 degree medial 4.5 cm 
    • Opthalmic
    • Towards
    • 20 cm/s 
    • High pulsatility, high resistance

    • See carotid siphon:
    • Parsella- above
    • Genu- superior- bidirectional
    • Supraclinoid - superior 40-50 cm/s
  65. Subocciptal:
    • Foramen Magnum
    • Vert A 6-9cm
    • Away
    • 40cm/s
    • bidirectional

    • Basilar A 8-12cm
    • 3-4cm long
    • Confluence of Vert A 40cm/s
  66. Submandibular:
    Evaluation of distal extradural parts (C5 and C6 segments) of the ICA.
  67. TCD
    Static Pulsed Wave
    0 degrees
  68. Autoregulation:
    The tendency of the blood flow to an organ or part to remain at or return to the same level despite changes in the pressure in the artery which conveys blood to it.
  69. Arterial Venous Malformation (AVM)
    Developed abnormally- arteries and veins are normal.
  70. Brain death:
    • 1. Clinical criteria
    • 2. EEG criteria
    • 3. Angiographic demonstration of absent intracranial circulation.
  71. Drop Attacks: Vertebrobasilar symptom
    -Collapse don't lose consciousness.
    Dysarthia: Difficulty speaking, tongue muscles, not working properly
    Dysphagia: difficulty swallowing
    Dysphasia: difficulty with speech
    Intracranial: within the cranium
    Infarct: death of tissue
  72. Hypoplastic: small or not there vessel system
    Hypo perfusion: low blood pressure
    Traceability: Refers to the fact that the MCA can be tracked in increments or steps from a more shallow intonation depth to depths with out changes in the character flow profile and flow direction.
  73. Cerebral Aneurysm:
    Spontaneous rupture of aneurysms typically results in SAH and affects up to 30,000 patients annually.
    10-15% of people with a ruptured aneurysm die before reaching the hospital
    40% die in 1 to 3 months
  74. Non-traumatic-Saccular aneurysms occur in the anterior circulation approx. 90% of the time and approx. 10% of the time occur in the posterior circulation.
    1-5% of the population harbors an enraptured aneurysm.
  75. Surgical Clipping
    • Main treatment of both ruptured and enraptured cerebral aneurysms did it this way for years.
    • Artery is exposed and the aneurysm visualized directly.
    • Surgeon applies a metal clip to the aneurysm thereby blocking the blood flow into the aneurysm.
    • Cutting off flow to the aneurysm eliminates hemorrhage.
  76. Guglielmo Detachable Coiling (GDC)
    • Soft platinum coil with circular memory attached to a delivery mandrel.
    • Coil attached to mandrel by a soldered joint and can be detached by way of a micro catheter placed into the aneurysm.
    • The goal is to prevent flow into the sack of the aneurysm by filling the aneurysm with coils and thrombus.
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