URR other cerebral abnormalities

Question 1

vertebral artery stenosis

Answer 1

-difficult to diagnose with US due to portions of the a are located within the trans proceses of the vertebrae
-normal flow is low resistive
-most common location of stenosis is at the vertebral origin
-can lead to steal phenomenon

Question 2

diagnostic criteria for vertebral artery stenosis/occlusion

Answer 2

-abnormal PSV > 100 cm/sec in most stenosis
-ratio of pre and post stenotic velocities >2
-abnorm pulsatility (biphasic or triphasic)

Question 3

-occlusion or stenosis or prox subclavian artery
-most common on left side
-dist subclavian artery fed by reversed flow through ipsilateral vert artery
-retrograde vert flow on affected side
-if suspected, bilat brachial pressures should be obtained, decreased or greater than 20 mmHg will be seen on affected side
-symptoms include limb paralysis, vertigo, ataxia, and syncope

Answer 3

subclavian steal

Question 4

subclavian steal happens more often on what side?

Answer 4

left

Question 5

proactive maneuvers can be done to make partial or complete steal

Answer 5

-if bidirectional or biphasic in vert , exercising the arm or applying a blood pressure cuff can be used to convert the flow to complete steal
-if suspected subclavian a should be evaled, mono flow detected on affected side
-ask patient to perform 40 flexion/ extensions of arm on affected side then re-eval the vert flow
-inflate above syustolic pressure on ipsilat arm and maintain for 1-2 mins, replace cuff and asess flow in abnormal vert a, if steal present, the flow should change from biphasic to complete reversal

Question 6

early systolic deceleration in vert a

Answer 6

-stenosis of subclav a can cause changes in vert a flow
-systolic deceleration is a sign of a significant stenosis in ipsilat side
-systolic flow starts with sharp peak followed by a sharp decrease in flow to baseline
-then resumes, increase to decrease through diastole
-this is caused by stenosis in subclav a and less commonly the prox vert A
-waveform is considered a sign of “pre steal”
-provacative maneuvers can be done to make partial or complete steal

Question 7

-inflammation of A wall
-causes difffuse or focal thickening of muscle layer
-may cause increased vasc in wall of inflamed segment
-increased velocities with decrease lumen size

Answer 7

arteritis

Question 8

buerger, takayasu, polyarteritits, temporal (giant cell)

Answer 8

types of ateritits

Question 9

the superficial temporal A courses anterior to the ear and can be palpated just above what?

Answer 9

the zygomatic arch

Question 10

-inflammation of the superficial temp A leading to flow reduction to frontal and parietal branches
-stiffness in neck, jaw, claudication, headaches, and sudden uni blindness
-biopsy necessary for diagnosis

Answer 10

temporal arteritis (GIANT CELL)

Question 11

what does temporal arteritis look like?

Answer 11

-images have thickened walls
-halo sign = ring of thickened vessel wall surrounding vessel
-normal flow patterns mimic ECA
-diffuse vessel wall thickening and distal ischemia cause increase velocity and decreased flow resistance
-areas of greater wall thickening can cause focal stenosis with increased resistance prox to stenosis and decrease resistance distal to stenosis

Question 12

aneurysms area rarely seen where?

Answer 12

cervical carotid branches

Question 13

if an aneurysm is found in intracranial vessels, it is what kind?

Answer 13

berry

Question 14

-blood escapes into surrounding tissues and becomes encapsulated
-risk of hemorrhage/death, trauma, infection, or true aneurysm

Answer 14

pseudoaneurysm

Question 15

what is an AVM?

Answer 15

congenital connection between arterioles and venules (lack of capillary bed); usually has multiple connections and surrounding venous collaterals and dilated veins

Question 16

severe form of intracranial AVM in fetuses?

Answer 16

vein of galen aneurysm

Question 17

what is an AV fistula?

Answer 17

direct connection between aterial and venous systems caused by tauma or vascular procedure, usually single connection and no surrounding collaterals
-causes increased volume of flow in venous system with pulsatility and turbulence
-reduces resistance in arterial inflow and increased diastolic flow
-large or chronic arteriovenous connections can lead to heart failure

Question 18

-acute tear in vessel intima
-creates false lumen
-associated with marfan syndrome and ehler danlos syndrome

Answer 18

dissection

Question 19

if ICA affected by dissection, usually affects which part?

Answer 19

first 2-4 cm

Question 20

CCA dissection can by continuation into where?

Answer 20

aortic arch

Question 21

dissection is more common in ICA or ECA?

Answer 21

ECA

Question 22

-collagen growth in medial layer
-most common in renal A
-usually occurs mid-distal ICA (atherosclerosis more common in prox)
-causing flow limited lesions

Answer 22

fibromuscular dysplasia

Question 23

what does fibromuscular dysplasia look like?

Answer 23

-string of pearl appearance
-abnorm growth of medial layer
-doesnt shadow
-causes stenosis/occlusion

Question 24

carotid body (sinus):

Answer 24

-located at CCA bif, near angle of jaw
-above this numerous baroreceptors are located to monitor BP

Question 25

what is the therapeutic and diagnostic carotid sinus massages?

Answer 25

therapeutic:
-used to interrupt paroxysmal atrial tachycardia
-performed to reduce heart rate
-causes transient block in conduction of the electrical signal in heart
diagnostic
-used to eval patients hypersensitivity of the sinus
-may be performed if no stenosis in extracranial As
-abnormal response will lead to hypotension, bradycardia, and dizziness

cant be performed on patients with hx of TIA, bruit, or stenosis

Question 26

carotid body tumor/glomus tumor, chemodectoma/paraganglionoma?

Answer 26

-rare neoplasm composed of paraganglion tissue
-more common in females
-seen in people living in high altitudes
-high vasc structure fed by ECA
-overgrowth of normal structure that is responsible for detecting blood gasses/pH
-can compress ICA
-pulsatile lat cervical mass
-dysphasia, syncope, hoarseness, dyspnea, cough
-horner syndrome
-pharyngeal bulge

Question 27

thromboembolic disease?

Answer 27

-thrombus accumulation within arterial system that produces embolisms that travel distally
-symptoms vary with occlusion site of embolism
-can cause multiple TIAs

Question 28

neointimal hyperplasia (myointimal hyperplasia)

Answer 28

-intimal thickening post endarterectomy or stent placement (smooth muscle rapid thickening)
-flow limitations lesions
-causes higher velocities in ICA
-leads to restenosis or occlusion within 2 years of surgery

Question 29

PHACE syndrome

Answer 29

-Posterior fossa malformations (such as dandy walker) , Hemangioma, Arterial anomalies, Coarctation of the Ao and other cardiac anomalies, Eyes
-arterial stenosis or occlusion of cerebral As
-abarent origin or coarse
-saccular aneurysms of any cerebral As

Question 30

-elongation of the styloid process or a calcified sytlohyoid ligament causes carotid compression
-most common bilat
-visual disturbances, syncope, carotid dissection

Answer 30

eagle syndrome

Question 31

increased heart output can cause ?

Answer 31

increased flow in As

Question 32

decreased heart output can cause ?

Answer 32

reduced resistance and flow velocity in A system and pulsatile flow in venous system

Question 33

right heart valvular disease can cause abnormal?

Answer 33

pulsatile decreased flow

Question 34

80-90% of atrial emboli are from what?

Answer 34

cardiac source

Question 35

atrial fibrilation (irregular HR) can lead to clot formation in the left atrium which could lead to what?

Answer 35

-if it breaks off, can float anywhere
-if foramen ovale is patent, could go into right heart

Question 36

aortic stenosis?

Answer 36

-usually degenerative disase causes but can also be from congenital malformation of bicuspid valve
-flow increases in velocity
-flow into ascending aorta will be turbulent
-brachial pressures decrease
-characteristics can be passed to carotids

Question 37

aortic regurgitaiton

Answer 37

-blood flows back through aortic valve to left ventricle during diastole
-caused by disease valve, congenital defects, and chamber of aortic dilatation
-significant can lead to volume overload occurs in left vent
-pulsns bisferiens can occur in carotis
-waveforms have double diastolic peaks
-severe regurg is associated with diastolic flow reversal in carotids (water hammer pulse)

Question 38

mitral stenosis

Answer 38

-bilat tardus parvus in CA can indicate severe
-blood flow reduced in left atrium to left vent
-significant stenosis can cause left atrial pressure overload with reduced cardiac output
-CA will have low resistance, low velocity

Question 39

mitral regurg

Answer 39

-blood moves back through mitral valve into left atrium during systole
-caused by diseased valve, congenital defects and changer dilatation
-significant regurg results in volume overload in chamber recieving the retrograde flow
-with mitral regurg, volume overload occurs in left atrium
-usually has no effect on atrial or venous doppler

Question 40

cardiac temponade?

Answer 40

-critical
-severe pericardial effusion within fibrous pericardium causes intrinsic compression of right heart chambers
-respiratory variation in arterial flow
-flow decreases with inspiration and normalizes with expiration
-another indication: pulsus alternans(peak systolic velocity alternates btwn 2 levels with each beat), also associated with dilated cardiomyopathy and constrictive pericarditis

Question 41

intra-aortic balloon pump (IABP)

Answer 41

-for severly and left vent function
-implanted in descending ao and expands and contracts to cause blood to flow
-have 2 systolic peaks for each pulse
-2nd : balloon inflation
-EDV cant be determined because of flow reversal

Question 42

left vent assist device (LVAD)

Answer 42

-used for end stage heart failure
-can prolong life for transplant patients and those who cant transplant
-pulls blood from LV into a pump transports blood to AO
-brachial measurements must be recorded
-diminished PSV, increased diastolic
-can cause fake negative for CA stenosis