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74 Cards in this Set
- Front
- Back
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what are lacunar strokes?
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occlusion of small arteries(branches of circle of willis or basilar arteries)
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the anatomic variation that most decreases collateral potential for the brain is what?
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absent or hypoplastic posterior and anterior communicating arteries
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what happens when there is occlusion or narrowing of veins?
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poor tissue health due to lack of blood flow and fluid away from the tissue. fluids and toxins accumulate around tissue cells leading to poor ransportation of oxygen and nutrients to target cells tissue degrades and chronic skn ulcerations may result.
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If there is obstruction in the subclavian artery, what are some collaterals?
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-Blood from one VA to another
-Anterior and posterior circulations via the VA -ECA to ICA to VA -Occipital artery to deep cervical artery. -Cross over of inferior thyroid arteries -thryrocrevical trunk and spiral arteries -cross over via internal thoracic arteries -intecostal arteries and internal thoracic arteries |
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what do the branches of the basilar artery supply?
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-lateral aspects of the cerebrum
-pons -cerebellum |
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what are the usual sources of embolic strokes/
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from a cardiac or arterial source. the cadiac causes are related to arrythmias, endocarditis, recent myocardial infact, or valve diseases.
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What are the 3 components of color doppler?
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-Hue-BART
-Saturation-saturation is greater with less white present -luminence-brighness within the hue that represents echo intensity |
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where do intercerebral hemorrages originate? what are they caused by?
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orignate in small arteries, and are cuased by:
-hypertension -cocaine -trauma -bleeding disorders - |
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what are some collaterals if there is vertebral obstruction?
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-Contralateral VA
-Occipital branch provides flow via VA -thryocervical trunk and muscular branches of vertebral artery |
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What does range gating mean?
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sonographer can determine where in the body sampling takes place
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What are the 4 segments of the VA?
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1. extravertbral segment: from origin of VA at subclavian to transvers foramina
2. intervertebral segment:through the transvers foramina and courses btw C-6 and C-1 3. Horizontal segment: courses into the cranium before they peirce the dura mater. Courses medially and posteriorly. Branches into the posterior meningeal, and muscular branches 4. Intracranial segment:ascends from dura mater anteromedially through the foramen magnum and joins with the contralateral VA from the basilar confluence. |
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If there is ICA obstruction, what are some possible collateral routes?
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-circle of willis-only hypoplastic communicating arteries will prevent this flow
-ECA anastamoses -branches of the major cerebral arteries that connect across each vascular territory(called leptomeninges) -Transdural branches that are the surface arteries of the brain may connect to provide flow to starving tissue.(wonderful net/rete mirable? |
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when might the spectral doppler criterial not be valid?
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-if ther is tandem stenosis
-there is contralateral high grade stenosis -there is hyperdynamic flow -low cardiac output -CCA stenoiss -tortuosities -inaproppriate angle or estimate measurements |
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what is a subarchnoid hemorrage?
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a rupture of a larger artery ito the cerebrospinal fluid of the subarchnoid space. THey cause intracerebral aneurysms or arterial malformations
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When plaque is complex, what does this suggest?
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more than one cycle of hemorrhage and repair.
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homonymous heianopia
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blindness in the corresponding right and left visual fields.(loss of 1/2 of the visual field of both eyes that may occur after a stroke)
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what are the anatomical variations of the carotid artery?
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-Lt CCA originates from right brachiocephalic trunk(9%)
-Rt and LT brahciocephalic trunks(1%) -ICA tortuous and kinky -bifercation levels in the neck -various configurations of carotid bulb. |
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when may aliasing occur?
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-inappropriate display of doppler spectrum due to low sampling rate for PRF.
-system is sampling deep into tissue(increases PRF) |
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how does hypertension contribute to atherosclerosis?
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ishemia of endothelial cells, force lipid to filtrate into the vessel wall.
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what are the general categories of cerebral vascular disease?
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coronary artery disease
cerebrovascular disease peripheral arterial disease |
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what do macrophages secrete?
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TFN, and other cell destructive substances
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explain non-ultrasound modalities that are used for vascular testing?
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-blood pressure
-limb volume changes -oxygen saturation |
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how does cigarette smoking contribute to atherosclerosis?
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roughens the lining of the arteries/
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What is another name for the character of flow?
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flow profiles-cells within blood move against eachother and against walls of the blood vessels to create certain resistance to flow.
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what are the intracranial branches of the ICA?
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caroticotympanic
ophthalmic meningohypophyseal |
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What are the routes for intracranial collateral circulation?
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-large interarterial connections
-intracranial-extracranial anastomoses -smaller interarterila communications |
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Describe the ECA and its branches
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These branches primarily profuse the face and scalp;
-Anterior:Superior thyroid, lingual, and facial -posterior:occipital, posterior auricular -ascending:ascending pharyngeal -terminal: superficial temporal, internal maxillary |
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When does aliasing occur?
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when the doppler frequency shift exceeds one half of the PRF. (niquist limit)
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what is a watershed stroke?
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blockage of supply to brain tissue supplied by small end arteries. It is caused by hypoperfusion such as large arter occlusions, systemic hypotension, or cardiac failure.
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what is the sequence of events in plaque formation?
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lipid infiltration, formation of foam cells, transformation of muscle cells into fibroblasts
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How can spectral broadening be helped?
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How can spectral broadening be helped?
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what is small vessel disease?
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results due to occlusion from thrombi in the small branches of the circle of illis or basilar arteries.
-as a result of lipid and/or fibrin build up due to aging and hyprension. |
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what happens if there is basilar obstruction?
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arterior to posterior circulations
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transmural pressures
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difference btw intramural and extrinsic pressures(what affects the shape of the vein eall)
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what is the correct term for the chronic phase of venous thrombus?
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chronic post thrombotic scarring
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anterior tibial veins
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-paired veins
-continuous of the dorsalis pedis veins -anterior to tibia -enter popiteal fossa laterally -join posterior tibial and peroneal to form pop v. -drain blood from anterior compartment of lower leg |
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INR
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international normalized ratio-standard reagent used to examine clotting time.
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what are some signs that may be a result of DVT?
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-Homan's sign-pain with dorsiflexion
-bancrofts sign-tenderness on anteroposterior but not lateral compression of calf -lownburg's sign-pain in the calf caused by BP cuff inflation to 80mmhg (these signs are present in about 1/3 of patients with DVT) |
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primary hyperhomocysteinemia
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-elevation of coagulation factors VIII, IX, XI
-associated risk of VTE and atherosclerosis |
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pulmonary embolus
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an obstruction of the artery in the lungs.
-caused by an embolized material which may be fat, tumor, air or blood clot. -The blocked artery causes ischemia to the lung tissue (infarct) and increased right heart pressures, which could lead to heart failure. -Severity of the ischemia depends on the size of the artery blocked -one emboli presents a very high risk of more to follow. |
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hypercoagulability
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-increased estrogen(pregnancy, BCP use)
-cancer -genetic blood factor deficiencies |
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what is the normal sample volume size?
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1.5 cm
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soleal sinus
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thin walled
usually 6-8 of them lie within soleal muscle and empty to posterior tibial and peroneal veins |
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resistance to activated protein C
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aka factor V leiden
-most common inherited hypercoagulable condition -associated with VTE |
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what will be seen when there is an obstruction proximal to the site of insonation? distal?
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loss of phasicity; doppler signal is continous and less responsive to valsalva maneuver.
-distal obstruction will caused reduced velocity and amplitude. |
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what happens in regards to muscle pumps with muscle contraction
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-blood is squeezed by force agains veins
-valves open to allow upward flow -capillary pressure reduced reducing filtration -perforator veins squeezed -superficial veins move upward -sinuses are sqeezed and drained |
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posterior arch vein
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-posterior to medial malleolus
-main tributary of greater saphenous vein -communicates with deep veins |
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phasicity
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-during inspiration where there is no flow from the IVC, it is refilling with blood from LE. btw the IVC and LE veins(lower extremity), they are 180 degrees out of phase with eachother.
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what are some factors that limit blood clot formation?
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protien c
fibrinolytic sytem |
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Factor II(prothrombin)mutation
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-usually european descent
-2.8 fold increase in VTE risk |
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WHat are some acquired risks for VTE?
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Immobilization, stroke, cigarette smoking, pregnancy, obesity, kidney disease
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what are the three factors included in virchows triad?
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venous stasis, intimal injury, hypercoagulability
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when upper extremity thrombus is present and there has not been a needle stick injury, what should be considered?
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thoracic outlet syndrome
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PT
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prothrombin time-used to examine the time it takes for lood to clot. If blood clots faster than normal, VTE is more likely
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what factors affect clotting factors?
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-excersize
-alcohol consumption -foods |
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what are the layers of a vein? What do they contain?
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tunica intima-contains valves(we asses valves regularly, as as you move further down the body, there are more valves)
-tunica media-thinner than the artery. |
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what are the upper extremity superficial veins?
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Cephalic vein
basilic vein median cubital vein external jugular bein |
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what is the only surface that makes contact with blood?
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the endothelium
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Where does the CCA bifercate?
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at the level of the c4 spine
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what are the types of arteries?
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muscular(distribulting arteries)
elastic(function as a pressure reservoir) arteriole(Key role is regulating resistance) |
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LSC
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Left sublavian vein
-3rd branch of the aortic arch -corses upward and lateral to supply the Lt upper extremity |
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T/F If a blood clot forms in a superficial vein, there tends to be major problems.
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TRUE
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do capillaries have a tunica media or adventitia?
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no
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Why do veins vasoconstrict and vasodialate?
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-to maintain temperature
-maintian proer metabolic rates |
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What are the upper extremity deep veins
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Tadial veins
ultnar veins brachial veins axillary vein sublavian vein internal jugular vein innominate or brachiocephalic |
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what is complience?
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the elastic fibers allow for the artery to stretch in response to pressure within .
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what are the 4 peripheral systems?
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upper extremity-both arms and shoulders
lower extremity-both legs cerebral-neck veins and veins within the head central-all the veins within the abdomen |
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what is the normal relationship btw the splenic vein and SMA?
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THe splenic vein is anterior, and runs perpendicular to the SMA
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Describe the course of the veins that make up the portal vein
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SMV-Drains blood from the small intestine, and portions of the large intestine, stomach, and pancreas
-IMV-passes into the splenic vein, and drains a portion of the lg. intestine. -splenic vein-drains blood from the spleen, pancreas, stomach, and part of the lg. intestine. |
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what vessel passes anterior to the uncinate process?
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SMV
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What are metarterioles?
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a channel directly btw an arteriole and a venule that causes blood to bypass the capillary system.
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what are the branches of the IVC in order from origin?
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Right gonadal, Renal, adrenal, hepatic
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what are the 3 branches of the celiac axis, and descrie the route that each takes to it's respective organs.
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splenic artery-Comes off to the left, and travels along the superior border of the pancreas. It supplies the spleen, and pancreas.
hepatic artery-Comes off to the right. IT is lateral and anterior the the main portal vein. It supplies the left lobe Lt gastric artery-travels supreior and to the left. It supplies the stomach and esophagus |
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what is the vasa vasorum?
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blood suply and drainage neetwork for blood vessels found within the adventicia.
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