Periorbital Doppler

Front 1

explain the anatomy of the common carotid artery?

Back 1

-5-6mm in size
-rt CCA originates from the brachio-cephalic artery
-lt. CCA originates from the aortic arch
-bifercates into internal and external carotid artery

Front 2

what is the carotid bulb

Back 2

-the enlarged portion of the distal CCA(can be part of the proximal internal carotid artery)
-has baroreceptors that sense and regulate blood pressure

Front 3

explain the anatomy of the ICA?

Back 3

-approx 4mm
-usually posterior and lat to ECA, but 15% of the time its reversed
-supplies anterior brain, eyes, forehead, and nose
-enters the skull through the carotid canal
-the first branch is the opthalmic artery
-after this branch, it joins the circle of willis and gives off the anterior choroidal and posterior communicating arteries before it divides into the anterior cerebral artery and middle cerebral artery

Front 4

what portions is the ICA divided into?

Back 4

-Cervical
-petrois
-cavernous(siphon)-s-shaped
-supraclinoid

Front 5

what are the branches of the opthalmic artery? What do they supply

Back 5

-central retial artery-supplies the eye
-suptraorbital artery-courses ant. and sup. till it reaches the globe, then joins the ECA via the superficial temporal artery
-frontal artery-exits orbit medially to supply midportion of the forhead; joins ECA via superficial temporal
-nasal artery/angular artery -branches off the fronatl artery to supply the nose. courses down lateral border of the nose. Joins ECA via the facial artery

Front 6

Explain the anatomy of the ECA?

Back 6

-3mm
-anterior and medial to ICA
-gives off branches right away
-has eight branches that supply the face, neck, thyroid, ear, scalp and dura maater

Front 7

what are the eight branches of the ECA?

Back 7

ascending pharngeal artery
superior thyroidal artery
lingual artery
posterior aurical artery
internal maxillary artery
superficial temporal artery
transverse facial artery
occipital artery

Front 8

explain the anatomy of the vertebral artery

Back 8

-originates from subclavian arteries
-usually assymettric(rt smaller)
-enter vertebral space at the level of the C6 and course through foramina
-exit vertebral foramina at C1 and enter skull through the foramen magnum
-joint together to form the basiar artery

Front 9

what do the vertebral arteries join together to form?

Back 9

basilar artery

Front 10

explain the anatomy of the circle of willis?

Back 10

-vessels that lie at the base of the brain connecting the ant. and post. circulatory systems
-normal circle of willis occurs only18-20% of the time
-provides NB collateral pathway in case of stenosis or occlusion

Front 11

what is the most common varient of the circle of willis?

Back 11

-hypoplastic ACA

Front 12

name and explain the arteries that the circle of willis is made up of?

Back 12

-Anterior cerebral artery-carries 20-30% of the blood to the brain
-middle cerebral artery-carries 70-80% of blood to the brain
-post cerebral artery
-basilar artery-formed by vert. arteries and supplies blood to posterior structures
-distal ICA
-ant. communicating artery
-post communicating artery

Front 13

Explain the proportion of blood going to the brain?

Back 13

-75% of blod is sent through the ICA's(each delivers 300-400mL of blood/min)
-25% is via the vertebral arteries(100ml/min)

Front 14

name and explain the two systems that the brains blood supply is divided into?

Back 14

-Anterior circulatory system: made up of carotid arteries and their branches
-Posterior circulatory system:made up of vertebrobasilar arteries and their branches

Front 15

what are the major collateral pathways via the circle of willis?

Back 15

-ECA to ICA via the opthalmic artery
-Crossover collateral via the ACA
-post. to ant. collateral via the PCA

Front 16

what are the different types of intracranial to extracranial anastamosis?

Back 16

-connections via the opthalmic and orbital arteries, the meningophophyseal branches, and the carotid-typanic branches
-connections via the occipital branch of the ECA and the atlantic portion of the vertebral artery
-ECA's connections across midline
-Deep cervical and ascending cevical branches of the subclavian artery to the lower vertebral artery, atlantic portion of the vertebral artery, and the occipital branch of the ECA

Front 17

what are the major pathways available for transfusions?

Back 17

-circle of willis
-intracrantial to extracranial
-smal intraarterial communications

Front 18

what is the most commonly affected artery for stroke?

Back 18

the MCA

Front 19

If a person has an ICA stroke, what symptoms would be seen?

Back 19

-contralateral weakness, paralysis, numbness, and/or sensory changes
-ipsilateral amaurosis fugax, and or bruit
-aphasia or altered level of consiousness

Front 20

if a person has an MCA strok, what are the possible symptoms?

Back 20

-ashasia or dysphasia
-severe contralateral hemiparesis
-dysarthria
-behavioral changes
-confused state
-possible agitated deliruim

Front 21

what are the frequently seen symtoms of posterior cerebral artery stroke?

Back 21

dyslexia and coma

Front 22

what are the limitations of periorbital doppler?

Back 22

-cannot differentiate btw a tight stenosis and occlusion
-not diagnostic when there is a lesion that's not hemodynamically significant
-requires considerable skill

Front 23

Explain how periorbital doppler is done?

Back 23

-8-10mHz transducer
-locate frontal artery(flow should be antegrade)
-compressions are done on facial artery, superficial temporal artery, infraorbital artery, and CCA(ipsilateral, and contralateral)(not at bulb)
-test may be repeated using the supraorbital artery superior to the eye

Front 24

If flow in the frontal artery is retrograde, what does this indicated?

Back 24

-hemodynamically significant lesion in the ipsilateral ICA

Front 25

If flow in the frontal artery is diminished or reversed during compression maneuvers, what does this indicate?

Back 25

-the frontal artery is being supplied by collateral flow from the artery that is being compressed(secondary to hemodynamically significant lesion in the ICA.)

Front 26

If the CCA is compressed on the same side of the frontal artery, what should flow in th frontal artery look like? what is abnormal/

Back 26

should dimish as it decreases flow to the brain
-reversed flow may be evident if there is collaterals

Front 27

what are some other diagnostic tests for cerebrovascular testing?

Back 27

-MRI
-angio
-CT

Front 28

look at pictures in notes, and figure out what happens when you compress each artery

Back 28

Very NB

Front 29

What is OPG-Gee

Back 29

-an indirect test
-provides info about hemodynamically significant lesions in the ICA as well as indirect info about the development of collateral channels that provide blood to the brain

Front 30

what are the limitations of the OPG-G test?

Back 30

-cannot determine exact location of stenosis
-cannot differnetiate btw rt stenosis and occlusion
-non-diagnostic when evaluating well-collateralized lesions or non-hemodynamically significant lesions
-not usedful for documentation of the progression of disease

Front 31

what are the contraindications for OPG-G?

Back 31

-patients w/ glaucoma
-patients w/ allergies to local anesthetics
-patients w/ hx of or potential for retial detachment
-patients who have had eye surgery within 6 months
-patients who have acute or chronic conjunctivitis
-patients who cannot hold their eyes open

Front 32

What are the side effects that occur with OPG-G testing?

Back 32

-subjunctival edema(redness and tearing-usually disappears within 30 minutes)
-severe redness of the sclera
-pt. should not rub eyes for a while

Front 33

how is the OPG-G test done?

Back 33

-patient supine
-bilateral brachial pressures taken(if BP<140, 300mmHg may be used; If BP>140mmHg, 500mmHg may be needed to obliterate flow)
-local anesthetic applied to eyes
-eye cups placed on lateral sclera(white of the eyes)
-vacuum applied to cups deforming the shape of the globe, and increasing intraocular pressure
-strip chart recordings are made as pressure increases to obliterate arterial flow-patient may experience temporary loss of vision
-as vacuum is released, pulse returns when the opthalmic arterial pressure exceeds the introcular pressure
-pressure in the opthalmic artery reflects the pressure n the distal ICA

Front 34

when does the waveform for OPG-G return? What does the pressure in the opthalmic artery reflect?

Back 34

when the opthalmic arterial pressure exceeds the intraocular pressure
-the pressure in the opthalmic artery reflects the pressure in the distal ICA

Front 35

why would carotid compression maneuvers be used while administering OPG-G test? What is NB to remember when doing these tests?

Back 35

-to determine info about collateral pathways in the brain.
-never compress both carotid arteries or the bulb
-compressing the bulb may disturb the heart rate or rhythm, decrease cerebral perfusion, or cause distal embolization from dislodged plaque
-carotid compressions should be released slowly to prevent the sudden return of blood flow

Front 36

Explain how carotid compressions are done with OPG-G testing?

Back 36

-carotid artery is compressed for 3-5 seconds while the OPG maintains an intraocular pressure of 60mmHg
-If pulsations are noted during this, then the carotid artery is compressed for < or equal to 15 seconds while the OPG decreases the intraocular pressure from 110mmHg to the level at which the pulsations reappear.
-carotid compressions should be released gradually to prevent the sudden return of blood flow

Front 37

HOw are OPG-G tests analyzed?

Back 37

-pressures btw eyes shouldn't differ by 5mmHg or more. If they do, there is likely arterial disease on the side with the lower pressure
-if the opthalmic systolic pressures are >140mmHg, the amplitude of the first pulse should be measured, and it should be < or equal to 2mm
-normal ratio btw opthalmic systolic presure, and brachial systolic pressure should exist which is displayed on a scoring grid.

Front 38

diff. btw penetrating arteries supplying the brain, and diffuse superficial arteries

Back 38

-Penetrating arteries; neuronal function and nutrient supply for CNS
-Diffuse superficial arteries: collateral circulation routes including circle of willis and major arterial trunks

Front 39

name the periorbital arteries?

Back 39

frontal-inner canthus1-2cm
supraorbital=middle of the eye=2cm
opthalmic=5-6cm

Front 40

what are the 3 categories of intracranial collateral circulation/

Back 40

-large interarterial connections
-intracranial-extracranial anastamosis
-small interarterial communications
(major pathway is the circle of wilis)

Front 41

what is the 2nd most NB collateral circulation routes?

Back 41

perswillian anastamosis

Front 42

what collateral pathways come from the ICA? ECA?

Back 42

ICA- supraorbital, frontal, nasal, and opthalmic
ECA-superficial temporal, facial, infraorbital

Front 43

what is the initial technique of periorbital doppler?

Back 43

-patient supine
-eyes closed lightly
-investigate flow in supraorbital and frontal artery to see which one is stronger

Front 44

what compression maneuvers should be done for periorbital doppler?

Back 44

-temporal artery
-both supraorbital arteries
-both facial arteries
-CCA on ipsilateral side(1-3 heartbeats)
-contralateral CCA compression if ipsilateral compression is normal

Front 45

if you compress two arteries simultaneously and there is flow change, what should you do next?

Back 45

compress arteries individually; by compressing one artery at at time, you can determine which vessel is feeding the periorbital vessel

Front 46

If there is flow reversal in the supraorbital or frontal artereis with compression of any of the compresion sites, what does this indicate?

Back 46

-significant(>50%) ipsilateral ICA stenosis, or occlusion
-reverse flow in any of these branches indicates that they are providing collateral circulation to the brain

Front 47

What is normal and abnormal to see with ECA branch compression?

Back 47

normal=no change or rise
abnormal=diminished or reversed=artery compressed provides collateral flow

Front 48

If you compress the CCA on the same side of the head that you're doing doppler, what should it look like normally? abnormal?

Back 48

normal:
-decreased or obliterated or reversed periorbital signal
-ECA supply cut off
ABNORMAL:
-no response means that the circle of willis providing collateral flow

Front 49

summerize the finding that would be considered abnormal in regards to periorbital doppler?

Back 49

-reversal of flow in either the frontal or supraorbital arteries
-flow reversal(or decreased flow) with ECA branch compression
-failure of flow to diminish with ipsilateral CCA compression
-decrease of flow with contralateral CCA compression

Front 50

what are the capabilites of periorbital doppler?

Back 50

-flow direction
-collateralization
-identifies or adds evidence to ICA stenosis

Front 51

what are the limitations of periorbital dopppler?

Back 51

-no quantification
-no exact location of disease
-doesn't differentiate btw stenosis and occlusion.

Front 52

What are the techinical errors that can be made w/ periorbital doppler?

Back 52

-ECA branches vs. opthalmic artery branches
-excessive transducer pressure
-inapropriate compression technique

Front 53

What could cause a false negative or false positive with periorbital doppler?

Back 53

false negative:
-combined ICA and ECA obstruction
-incorrect compression of ECA branches

False positive:
-improper doppler probe positioning
-inadequate CCA compression

Front 54

Explain supraorbital PPG

Back 54

detects flow changes in teh microcirculation as a result of hemodynamically significant carotid disease

Front 55

What is the patient position used for supraorbital PPG?

Back 55

-supine
-PPG's above inner half of each eyebrow
-set amplifier to AC
-obtain baseline pulse recording on the strip chart

Front 56

What is the technique for supraorbital PPG?

Back 56

-obtain signal from PPG
-optimally adjust pulse amplitude(25-30mmheight and paper speed at 5mm/sec)
-compress temporal arteries bilaterally(for 5 beats)
-depress foot switch at the same time of compression
-compress supraorbital
-compress both facial art.
-compress ipsilateral and contralateral CCA's(optional)

Front 57

What is normal for supraorbital PPG?

Back 57

-minimal decrease in flow w/ ECA branch compression
-compression of ipsilateral CCA resulting in attentuated pulse amplitude
-no change w/ contralateral CCA compression

Front 58

If siginificant stenosis is noted with Supraorbital PPG, what will be seen?

Back 58

-W/ temporal artery compression, theer is attenuation of pulse amplitude by >33%
-w/ infraorbital or facial artery compression, there is reduction or >15% or pre-compression amplitude

Front 59

If there is collateral flow present, what will be seen with supraorbital PPG?

Back 59

-Contralateral compression of the CCA shows attenuated amplitude meaning that there is significant stenosis of the ipsilateral ICA and collateral flow via the circle of willis
-no attenuation when either CCA is compressed means there is collateral flow via vertebrobasilar arteries

Front 60

What could cause a false negative or false positive with supraorbital PPG?

Back 60

False negatives:
-improper ECA branch compression
-ipsilateral ICA and ECA obstruction

False positives:
-vasoconstriction
-anomolous circulation
-improper compression of ECA

Front 61

What are the 2 types of occular plesthmography?

Back 61

oculopneumoplesthmography(air)(OPGGee)
oculopleythsmography(fluid)(OPG-K)

Front 62

when do pulsations in the ear arrive with OPG-Gee?

Back 62

at the same time as eye pulsations

Front 63

what can cause false negatives with OPG testing?

Back 63

-bilateral carotid artery disease
-stenosis<50%
-50-70% stenosis produces variable test results