Term
|
Definition
CVA. Aka;stroke. Permanent or semi-perminent impairment. |
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Term
|
Definition
TIA. Symptoms resolve within 24hrs. |
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Term
|
Definition
Weakness in one side of the body, face, arm, leg. Contralateral hemisphere. |
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Term
|
Definition
Total paralysis of one half of the body, face, arm, leg. Contralateral hemisphere. |
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Term
|
Definition
Numbness and tingling of extremities. Contralateral (opposite) hemisphere. |
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Term
|
Definition
Inability to speak or express oneself. Dominant hemisphere, usually left. |
|
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Term
|
Definition
Impairment of speech, lack of coordination and failure to arrange words in proper order. Dominant hemisphere. |
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Term
|
Definition
Imperfect articulation of speech due to disturbances of muscle control,slurring, dysfunction of any number of brain centers. |
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Term
|
Definition
Hemiparesis,hemiplegia, generalized weakness/motor dysfunction, parethesis & ipsilateral visual disturbances (amaurosis fugax). |
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Term
|
Definition
Aka: Transient Monocular Blindness(TMB). Ipsilateral (same side) artery. |
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|
Term
|
Definition
Gross incoordination of muscle movements, clumsiness of limb. Contralateral hemisphere. |
|
|
Term
Carotid Disturbance Symptoms |
|
Definition
Speech difficulty-usually left hemisphere,aphasia,dysphasia, dysarthria,sudden confusion,trouble understanding speech,sudden severe headache w/no cause & death. |
|
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Term
Vertebral-Basilar Symptoms |
|
Definition
Drop attack,blackouts,syncope,memory loss,vertigo,dizziness,diplopia(double vision),binocular blindness, headaches, neck pain & death. |
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Term
|
Definition
Cardiac:Emboli(free floating), cessation of perfusion. Carotid Etiology: About 50%, thrombosis (stenosis=artery,clot=vein. Aneurysm Rupture: Intracranial hemorrhage, vasospasm. |
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Term
|
Definition
Complete lack of blood flow. Narrowing getting reduced blood flow, enough until exertion. |
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Term
Cerebrovascular Risk Factors |
|
Definition
Family history of Peripheral Artery Disease (PAD), Smoking, Old age, Diabetes mellitus, Hypertension, High Cholesterol. |
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Term
First Branch of the Aorta |
|
Definition
|
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Term
|
Definition
|
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Term
|
Definition
|
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Term
|
Definition
Only 50% have an intact and working circle. Only 25% have the classic configuration. |
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Term
|
Definition
1.Patient History 2.Transverse Images 3.Longitudinal Images 4.Color Doppler 5.Spectral Doppler 6.Mapping areas of flow disturbance (pre-within-post) |
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Term
|
Definition
Alternate pathway for blood flow. |
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Term
|
Definition
|
|
Term
|
Definition
|
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Term
|
Definition
Should be going in the same direction as carotids. Antegrade. |
|
|
Term
% Stenosis via NASCET Method |
|
Definition
% Stenosis = 100*(1-Residual Lumen/True Lumen). |
|
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Term
|
Definition
Usually more low resistant. |
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|
Term
Carotid Criteria Caveat #1 |
|
Definition
Must have all Three: 1.Focal Velocity acceleration 2.Plaque 3.Post Stenotic Turbulence Criteria is only for grading stenosis not determining normal. |
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Term
|
Definition
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Term
|
Definition
Peak End-Diastolic Velocity. |
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Term
|
Definition
Significant velocity acceleration occurs at stenosis of 50% diameter or greater. Velocities do not appreciably increase over stenosis less than 50%. |
|
|
Term
Criteria Objective Parameters |
|
Definition
1.Stenosis diameter measurement (optional) 2.PSV at amx stenosis 3.EDV at max stenosis 4.ICA/CCA ratio 5.Absence of flow |
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Term
|
Definition
PSV at max stenosis/PSV from a disease free part of mid CCA. |
|
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Term
|
Definition
Loss of amplitude and delayed rise time. Seen distal to a stenosis. Suggests proximal stenosis. |
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Term
|
Definition
Used to hold a vessel open, pushes plaque against the vessel wall. Sampl prox,mid,distal,more distal. Hyperechoic, can look like x's. |
|
|
Term
Carotid Dissection Proximal |
|
Definition
In CCA, progression of Aortic dissection. False Lumen. Usually asymptomatic. ICA extension uncommon. |
|
|
Term
Carotid Dissection Distal |
|
Definition
Mid to distal ICA. No false lumen. Subintimal hematoma. Flow restrictive. Symptomatic. |
|
|
Term
Fibromuscular Dysplasia (FMD) |
|
Definition
A non-atherosclerotic, non-inflammatory arterial disease. Idiopathic. Fibrous thickening of the intima,media or adventitia. 90% women, w/hypertension, usually bilateral, prox. and dist. ICA. Seen as turbulence w/wo velocity increase. |
|
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Term
|
Definition
Aka; Chemodactoma. Highly vascular, often benign, often in "crotch" of bifurcation. |
|
|
Term
Carotid Criteria Caveat #2 |
|
Definition
Image is best with stenosis < 50%.
Spectral Doppler is best with stenois > 50%. |
|
|
Term
Society of Radiologists in Ultrasound (SRU) Recommmendations |
|
Definition
1.Gray scale,color & spectral doppler. 2.Doppler at 60° or less. 3.ICA from bulb to distal 4.Final report should discuss B-mode image and color doppler & technical limitations. 5. Compare to any previous reports in report. 6.Estimate degree of ICA stenosis. 7, Angiograms use NASCET method for stenosis. 8.Quality Assurance and internal validation. |
|
|
Term
Revised SRU Criteria Table |
|
Definition
% Sten. PVS Plaque Est. ICA/CCA EDV Normal <125 none <2.0 <40 <50 <150 <50 <2.0 50-60 >150 >50 2-4 60-100 ≥70230 >50 >4.0 >100 NearOcc Var Vis Var Var TotalOcc Undet Vis,No Lumen n/a n/a |
|
|
Term
|
Definition
Can be fixed. Use low PRF color scale and Power Doppler to find flow. |
|
|
Term
|
Definition
Can't be fixed. Really look with low PRF color scales and Power Doppler. |
|
|
Term
|
Definition
No established Criteria. If PSV increased by a factor of 2 over stenosis then probably a >50% stenosis. |
|
|
Term
|
Definition
Verify no flow. Check ICA & ECA. ICA is often supplied with retrograde ECA flow. |
|
|
Term
|
Definition
No established Criteria. Abrupt increase in velocity, w/post stenotic turbulence. |
|
|
Term
|
Definition
1.Poor Deployment 2.Stent Shift 3.Distal Stenosis |
|
|
Term
|
Definition
% Sten. PSV ICA/CCA 50-69% >225 >2.5 ≥70% >350 >4.75 |
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|
Term
|
Definition
The property of being echo-free or without echoes. |
|
|
Term
|
Definition
The property of being echo-free or without echoes. |
|
|
Term
|
Definition
Allowing the passage of ultrasonic waves without echoes. Anechoic. |
|
|
Term
|
Definition
Areas with similar echogenicity. Makes it more difficult to see the desired tissue structure. |
|
|
Term
|
Definition
Echogenic, the ability to create an ultrasond echo. |
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Term
|
Definition
Producing echoes of higher amplitude than normal for the surrounding medium. |
|
|
Term
|
Definition
Producing echoes of lower amplitude than normal for the surrounding medium. |
|
|
Term
|
Definition
Smooth, Irregular, homogeneous, heterogeneous. |
|
|
Term
|
Definition
Sharp, irregular borders. Higher risk of emboli. Ultrasound is not very good at determining plaque ulceration. |
|
|
Term
Intraplaque Hemorrhage (IPH) |
|
Definition
Hypoechoic area with thin fibrous cap. Ultrasound is not very good at determining intraplaque hemorrhage. |
|
|
Term
Subclavian Artery Exam Indications |
|
Definition
1.Supraclavicular Bruit (strange vessel sounds) 2.Reduced arm BPs 3.Abnormal vert. spectra or retrograde flow. 4.Arm weakness |
|
|
Term
High Resistive Vertebral Waveform |
|
Definition
Seen with distal stenosis in vertebral or basilar a. Proximal to stenosis. |
|
|
Term
|
Definition
More common on left. Flow from the rt, verts augments to supply flow to the lt arm. Usually no neurological symptoms. |
|
|
Term
Subclavian Steal Syndrome |
|
Definition
Subclavian steal & severe carotid disease. Causes neurologic symptoms. |
|
|
Term
|
Definition
If rt. vert has retrograde flow look carefully at innominate,CCA & rt subclavian. |
|
|
Term
Vertebral-Subclavian Assessment |
|
Definition
20mmHG gradient between left and right brachial pressures suggests subclavian stenosis. Don't take BP in an arm w/a shunt or dialysis access graft. |
|
|
Term
Early Systolic Deceleration |
|
Definition
"Bunny Ears". Seen in vertebrals with subclavian stenosis. Start of retrograde flow. Can turn into progressive early systolic decel, "to & fro" & retrograde flow (severe stenosis). |
|
|
Term
Subclavian Artery Waveform |
|
Definition
Triphasic: above/below/above. All peripheral arteries should have this form. Biphasic is abnormal! |
|
|
Term
|
Definition
85% of limb blood volume. Have an adjacent artery. Paired in the calf. Many "normal" variations. |
|
|
Term
|
Definition
Should be phasic, not continous. |
|
|
Term
Superficial Venous System |
|
Definition
Includes GSV & SSV. No adjacent artery. |
|
|
Term
|
Definition
Aka: Communicators. Coonects the superficial and deep systems. Flow from S to D. Dodd's Group,Boyd's PV & Cockett's Group. |
|
|
Term
|
Definition
Are only dialated when there is a clot. |
|
|
Term
|
Definition
|
|
Term
|
Definition
Confluence of superficial veins & GSV prior to joining the CFV through the terminal valve. |
|
|
Term
Blood Flow to Extremities |
|
Definition
Governed by: CO. Contractility of the heart. Arterial wall compliance. Intraluminal pressure. Peripheral resistance at the capillary bed. |
|
|
Term
|
Definition
Small arterioles leading into capillary beds are constricted in basal state. During exercise they vasodilate. Resistance down, flow up. Increased blood volume supports increased metabolic activity. More blood volume back to the heart. |
|
|
Term
|
Definition
Blood flows from areas of high pressure to areas of low. |
|
|
Term
|
Definition
The pressue that results from the force of fluid from a column of fluid. p=ρgh. About 22mmHg/12". |
|
|
Term
Approx. Distal Venous Pressures |
|
Definition
Lying: 0-10mmHg Standing: 80mmHg (based on height) Walking: 25mmHg |
|
|
Term
Hydrostatic Pressure Affect on Lower Veins |
|
Definition
Distal transmural venous pressure up, venous distension up, venous pooling up, capillary perfusion down, venous return down, cardiac output down, Hypotension results. |
|
|
Term
Cardiac Influence & Venous Flow |
|
Definition
This effect is most pronounced in the thoracic vessels, and is reduced in the lower extremities. If seen in the LE often means CHF. |
|
|
Term
Respiratory Variation & Venous Flow |
|
Definition
During inspiration (inhale) diaphragm moves down increasing intra-abdominal pressure. IVC is compressed and outflow is reduced or stops. Flow resumes during exhalation. |
|
|
Term
|
Definition
Foot Pump: primes the calf pump. Thigh Pump: ejects thigh blood volume. Calf veno-motor pump: major ejection. |
|
|
Term
Venous Valve Distribution |
|
Definition
IVC:0,CIV:0,EIV:0(IN MOST),FV:4,POP:2, PTVs:10,PVs:10,ATVs:10 |
|
|
Term
|
Definition
Helps venous return to the heart. Reduces the effect of hydrostatic pressure. Reduces venous pooling. Dependent on competent valves,muscle contraction & patency of outflow veins. |
|
|
Term
|
Definition
Aka: Venous Incompetence. Primary: congenital absence or defect of valves. Secondary: Postphlebitic syndrome;valves damaged by venous thrombosis or chronic outflow obstruction. |
|
|
Term
Venous Insufficiency Symptoms |
|
Definition
Recurrent swelling. Varicose/Spider Veins. Venous Claudication (pain in legs while walking). Stasis Dermatitis (brown "gator area"). Ulceration (usually in "gator area"). |
|
|
Term
|
Definition
|
|
Term
|
Definition
Applies to a clot anywhere, even in a test tube. |
|
|
Term
|
Definition
The formation of a blood clot in an artery or vein. |
|
|
Term
|
Definition
Actual clot within a vessel. |
|
|
Term
|
Definition
A thrombus that breaks free and travels. |
|
|
Term
|
Definition
Inflammation of vein wall. |
|
|
Term
|
Definition
Thrombus formation associated with phlebitis. |
|
|
Term
Superficial Thrombophlebitis |
|
Definition
Thrombosis in a superficial vein. |
|
|
Term
|
Definition
A thrombus that travels to the heart, through the heart and into the lungs. "Saddle" Embolus: In the Pulmonary Trunk at the bifurcation of Pulmonary Arteries. |
|
|
Term
|
Definition
1.Circulatory Stasis 2.Hypercoagulable State 3.Endothelial Injury |
|
|
Term
|
Definition
Post - operative state, previous DVT, cancer, thrombophilia, trauma, pregnancy, high dose estrogen RX, “economy class syndrome”, Bed-rest > 4 days, lower limb paralysis. |
|
|
Term
|
Definition
Persistent leg pain with acute onset. Persistent leg swelling. Calf pain/tenderness. If patients have above symptoms, 50% chance of DVT. |
|
|
Term
Clinical Diagnosis of DVT |
|
Definition
Low Sensitivity: Many DVTs are clinically asymptomatic.
Low Specificity: Non-thrombotic disorders can cause the same clinical symptoms as DVT. Ex.Cellulitis. |
|
|
Term
Phlegmasia Cerulea Dolens |
|
Definition
Symptoms with high positive predictive value for DVT. Massive thigh and calf swelling. Limb cyanosis. Ilio-femoral outflow obstruction. |
|
|
Term
Symptoms of Superficial Thrombophlebitis |
|
Definition
Erythemia (redness) / inflammation. Local tenderness. Palpable cord or mass. Usually more painful than DVT. |
|
|
Term
|
Definition
Swelling. Limb discoloration. Stasis dermatitis, ulceration. Varicose veins. Palpable “cords” (STP). |
|
|
Term
|
Definition
In order of importance: Compressibility / coaptation of vein. Visualization of thrombus. Spectral Doppler. Color Doppler. |
|
|
Term
Spectral and Color Doppler Techniques |
|
Definition
Longitudinal Evaluation: Spontaneous flow, phasic with respiration, augments with distal limb compression, reflux ? |
|
|
Term
|
Definition
Could be: Shallow breathers (patients with pulmonary embolus-PE). Patients who are lying supine. Patients who have their arms raised and hands behind their head. Spinal cord injured patients due to reduced abdominal muscle tone. Proximal DVT or extrinsic venous compression. |
|
|
Term
Common Femoral Veins & Doppler |
|
Definition
Always do both veins (bilaterally), for comparison, to rule out Iliac obstruction. |
|
|
Term
|
Definition
Thrombus from popliteal to iliac veins is Life Threatening. Calf vein DVT may cause PE but thrombus is too small to be fatal.Same for great saphenous thrombosis. |
|
|
Term
|
Definition
Acute: Distended,somewhat hypo-echoic, no collaterals,maybe free floating. Chronic: Contracted(smaller than artery),echogenic thrombus,presence of collaterals,recannalization. |
|
|
Term
|
Definition
If you find calf, SSV, or gastroc vein thrombosis, look carefully for extension into the popliteal vein. |
|
|
Term
Criteria for Venous Thrombosis |
|
Definition
Absence of vein compressibility. Visualization of thrombus. Vein distention. Abnormal Doppler signals. Reduced / absent augmentation. Reduced / absent color filling. |
|
|
Term
Differential Diagnoses: Leg Pain & Swelling |
|
Definition
Popliteal/Baker's/Synovial Cyst, Dissected Cyst, Popliteal Artery Aneurysm, Muscle Tear, Hematoma, Lymphedema-"Ant Farm", Cellulitis, May Thurner Syndrome, Tumor, Swollen Lymph Node, Abscess, Arterio-venous fistulas. |
|
|
Term
|
Definition
Compression syndrome. Compression/ thrombosis of left iliac vein by overlying right iliac artery. |
|
|
Term
Venous vs. Arterial Symptoms |
|
Definition
VENOUS ARTERIAL Acute onset Progressive Limb swelling Limb coolness Persistent pain Intermittent pain Local tenderness Limb pallor Palpable “cord” Gangrene Chest pain/SOB Tissue necrosis Cyanosis Rest Pain Warm |
|
|
Term
Comparison of Symptoms: DVT vs. Insufficiency |
|
Definition
DVT Insufficiency Persistent Swelling Recurrent Swelling Persistent Pain Heaviness/Discomfort Local Tenderness Varicose Veins Limb Warmth Stasis Dermatitis Short of Breath Ulceration |
|
|
Term
Venous Symptoms for Upper Extremities |
|
Definition
Pain & swelling in arm. SOB, Chest pain, Pulmonary Embolus? Dilated superficial veins of arm & shoulder. Local erythemia. Palpable cord. Catheter infusion difficulty. Pre-operative assessment for hemodialysis access placement. |
|
|
Term
|
Definition
Intimal injury: indwelling venous catheter, pacemaker wire, stents. Stasis: compression. Radiation induced. Fibrosis. Venipuncture. IV drug abuse. |
|
|
Term
Deep Veins of the Upper Extremities |
|
Definition
SVC, Innominate, Subclavian, Axillary, Brachial, Radial, Ulnar. |
|
|
Term
Superficial Veins of the Upper Extremities |
|
Definition
Basilic Cephalic Median Cubital |
|
|
Term
|
Definition
External jugular, Anterior jugular, Jugular arch vein, Transverse scapular, Inferior thyroid, Internal mammary. |
|
|
Term
|
Definition
Respiratory Phasicity & Cardiac Pulsatility. |
|
|
Term
Contralateral Assessment of the Upper Extremities |
|
Definition
Because subclavian waveform assessment is critical, it is important (& required by ICAVL) that a comparison be made with the contralateral subclavian vein. |
|
|
Term
|
Definition
Only Scan: Local palpable cord, suspicion of superficial thrombophlebitis, infusion difficulty with peripherally inserted central catheters (PICC lines), pre-op assessment for hemodialysis access placement(superficial veins only), pre-op for vein harvest for arterial bypass (determine patency and size). |
|
|
Term
Criteria for Venous ThrombosisUpper Extremities |
|
Definition
Visualization of thrombus, lack of vein coaptation, no flow in Color and Spectral Doppler, abnormal flow patterns and flow direction in central veins. |
|
|
Term
Paget-Schroetter Syndrome |
|
Definition
Spontaneous thrombosis of subclavian - axillary vein, effort induced, atomical factors, hypercoagulability. Extensive collateral development. |
|
|
Term
Superior Vena Cava Syndrome |
|
Definition
Occlusion or compression of SVC. Increased venous pressure. Edema of neck, face and arms, usually bilaterally. |
|
|
Term
Normal Upper Extremity Venous Interpretation |
|
Definition
1.All veins central to the axillary vein demonstrate cardiac pulsatility, respiratory phasicity, & central flow direction. 2.Color Doppler demonstrates complete intraluminal venous filling. 3.No intraluminal thrombus seen. 4.Contralateral subclavian vein flows are symmetrical. 5.Veins below the axilla are easily compressed & demonstrate complete filling with color when augmented distally. |
|
|
Term
Abnormal Upper Extremity Venous Interpretation |
|
Definition
1.Visualization of thrombus. 2.In the proximal veins, absence of spontaneous flow or absence of cardiac pulsatility. 3.Persistent retrograde flow in the IJV or EJV suggests obstruction in the Innominate vein. 4.Lack of compression of any vein below the axilla, confirmed by the absence of flow with Color or Spectral Doppler. 5.Absence of flow, or a filling defect in veins above the axilla. |
|
|
Term
|
Definition
Dilatation and expansion of arterial wall. May contain thrombus, platelet aggregates, debris. |
|
|
Term
|
Definition
Tobacco abuse. Hereditary/family history. Advanced age. Male gender (men are 5 times more likely). High cholesterol. Obesity. |
|
|
Term
|
Definition
Most intact aortic aneurysms are asymptomatic. Palpable pulsatile mass in abdomen. Back pain. Abdominal pain. |
|
|
Term
Abdominal Aorta Aneurysm Complications |
|
Definition
Rupture:Correlation between size and mortality rate. > 5cm Must be repaired. Thrombosis. Embolization. Males over 60 yrs old–highest risk group. |
|
|
Term
|
Definition
Intimal tear, blood in tunica media. Thoracic Aorta Dissection is an emergrncy! |
|
|
Term
|
Definition
Triphasic below the renals. Not triphasic above the renals. |
|
|
Term
Renovascular HypertensionCauses |
|
Definition
Atherosclerosis, usually in the proximal renal artery, is most common etiology. Fibromuscular dysplasia (FMD). Dissection or extension of aortic dissection. Renal artery stenosis must be ≥ 70% before it’s likely to cause hypertension. |
|
|
Term
Renal Doppler Indications |
|
Definition
Uncontrolled hypertension, especially in younger patients. Decreasing renal function. Abdominal bruit. |
|
|
Term
|
Definition
Identify vascular etiology of hypertension. Prevent renal failure due to permanent parenchymal changes. Evaluate renal transplants for complications. |
|
|
Term
Renal Doppler Patient Preparation |
|
Definition
Overnight fast,morning exam, patients should be well hydrated: some labs request that patients drink 16 oz of water 30 minutes before the exam. No chewing gum or tobacco, & no smoking prior to exam. |
|
|
Term
|
Definition
Measure each kidney length & compare to the contralateral side. A 2-centimeter difference is significant. Normal adult kidney length is 9-12 cm. |
|
|
Term
Main Renal Arteries-Normal Characteristics |
|
Definition
High flow velocity (PSV 100 ± 20 cm/s.) Low resistance (RI < 0.75) High diastolic flow vel. (EDV 30 ± 5 cm/s) |
|
|
Term
Renal/Aortic Peak Systolic Velocity Ratio (RAR) |
|
Definition
The highest velocity obtained in the renal artery divided by the peak velocity from the aorta. |
|
|
Term
Renal Doppler: Criteria for > 60% Stenosis |
|
Definition
Renal-Aortic Ratio (RAR) ≥ 3.5. Peak Systolic Velocity (PSV) > 180 cm/sec. Post stenotic turbulence. Low flow in distal renal artery. |
|
|
Term
Renal Doppler: Renal A. Occlusion |
|
Definition
No flow in well visualized renal artery. Low amplitude signal from parenchyma. Small kidney size (< 9 cm ). |
|
|
Term
Renal Parenchymal Disease |
|
Definition
High resistance flow in kidney and main renal artery. Velocity is reduced. |
|
|
Term
Renal Doppler: Indirect Criteria for > 60% Main Renal Artery Stenosis |
|
Definition
Sample Segmentals: Loss of early systolic peak (ESP). Acceleration time > 0.07- 0.1 sec. Abnormally low ipsilateral RI (< 0.75). Reduced color flow in kidney. Tardus Parvus Waveform. Flattened systolic upslope. |
|
|
Term
Renal Fibromuscular Dysplasia (FMD) |
|
Definition
Non-atherosclerotic, non-inflammatory arterial disease of unknown origin. Fibrous thickening of vessel wall. Predominance in women (90%). Associated with hypertension. Occurs in mid to distal segments of renal arteries. Can occur in carotid arteries. If renal artery stenosis is detected distal to the origin in mid segment, FMD should be suspected. |
|
|
Term
Renal Doppler & Transplants |
|
Definition
R/O kinks / twists in renal artery. RI for rejection: Normal 0.73 ± 0.04 Abnormal > 0.8 ± .07 RI not universally accepted. |
|
|
Term
|
Definition
|
|
Term
|
Definition
The energy level difference between two points. Must be present for fluid to flow from one point to another in a closed system. Fluid energy gradient is reflected in a pressure gradient. |
|
|
Term
|
Definition
Highest pressure in arterial system is in left ventricle & thoracic aorta during systole. The intra-arterial pressure in distal vascular bed is lower during systole, so blood flows towards the vascular beds. |
|
|
Term
Triphasic/Multiphasic Waveform |
|
Definition
Normal peripheral arterial waveform. In systole, intra-arterial pressure is high, flow moves forward. In diastole intra-arterial pressure is decreased and pressure distally is high (due to peripheral resistance)& flow reverses. Third component is thought to be due to the elasticity of the arterial wall (rebounding). |
|
|
Term
Laminar Flow vs. Parabolic Flow |
|
Definition
Laminar: A fluid flows in parallel layers with no disruption between layers. Parabolic: Describes velocity profile. |
|
|
Term
|
Definition
Resistance of movement of one layer of blood against another layer or a wall. The diameter of a vessel determines the amount of friction: the smaller the radius, the greater the friction and less amount of flow. |
|
|
Term
Plug Flow vs. Parabolic Flow |
|
Definition
Plug Flow occurs during acceleration. Systole: Plug Flow, narrow spectrum. Diastole: Parabolic Flow, wider spectrum. |
|
|
Term
|
Definition
Helical Flow & Flow Separation. |
|
|
Term
|
Definition
Property of fluid that resists flow. A friction that exists between adjacent layers of fluid or a wall. Higher viscosity, higher resistance to flow. Water has low viscosity compared to blood. Viscosity of Blood ∝ Hematocrit |
|
|
Term
|
Definition
As flow streams increase in velocity, a point is reached when laminar flow is disrupted. Flow becomes chaotic. Flow speed at which turbulence occurs depends on: Density of the fluid. Viscosity. Diameter of the vessel. |
|
|
Term
|
Definition
Unitless number; predicts turbulence. Reynold's#>2000 turbulence is likely. Re=inertial forces/viscous forces or Re=ρDv/η (density.diameter.velocity)/viscosity |
|
|
Term
|
Definition
The property that causes a fluid or object to resist a change in direction or speed. Friction, viscosity, & resistance are the foes of inertia.
Objects at rest tend to remain at rest… |
|
|
Term
|
Definition
Predicts flow in a cylindrical vessel. Relates Pressure and Flow Q=ΔPπr^4/8lη Assumes: Steady-State Flow, Rigid Flow Conduits and Newtonian Fluids. Which doesn't happen in the body. |
|
|
Term
|
Definition
|
|
Term
Simplified Law of Hemodynamics |
|
Definition
|
|
Term
|
Definition
V(voltage)=I(current)x R(resistance) Compare to: ΔP=Q*R |
|
|
Term
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Definition
Total energy at one location must equal all the total energy of another location. Total energy = potential energy + kinetic energy. |
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Term
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Definition
A 75 % area reduction (50% diameter if circumferential) will cause a velocity increase, and a distal pressure decrease. Velocity ∝ 1/area |
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Term
“Triggers” for Vasodilation |
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Definition
Low oxygen tension in tissue. Increased CO2 levels in tissue. Increase in lactic acid. Epinephrine from adrenal medulla. Increased potassium ions. |
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Term
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Definition
Normal: From triphasic to low resistance. |
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Term
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Definition
Familial/genetic component (Hx:CVA,TIA,MI). Cholesteral >240 mg/dl. Hypertension. Diabetes mellitus. Severe obesity. Elevated triglycerides. LDL > 160 mg/dl. Depressed fibrinolytic system. Tobacco abuse. Increased oxidation of LDLs. Hx: CVA,TIA,MI. |
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Term
Mild Occlusive Arterial Disease/PAD |
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Definition
Asymptomatic (ASX) Not hemodynamically significant. Mild decrease in ankle pressure w/exercise. Athero disease may be seen on US exam, but no flow reduction. Bruit. |
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Term
Moderate Occlusive Arterial Disease/PAD |
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Definition
Asymptomatic at rest. Intermittent claudication: Most common symptom of PAD. Pain, fatigue or cramping in calf, thigh or buttock w/exercise. Relieved by rest. Brought on by transient ischemic event in muscles. Exercise causes a significant decrease in ankle pressure. |
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Term
Severe Occlusive Arterial Disease/PAD |
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Definition
Night pain in feet/toes,relieved by dependancy. Dependant rubor. Ischemic rest pain in feet/toes. Non-healing wounds on feet/toes. Ulceration on lower leg or foot. Tissue necrosis, gangrene. |
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Term
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Definition
Buerger’s disease: Small vessel thrombosis,“fixed” occlusive disease. Raynaud’s syndrome: Small vessel vasospasm. Pulsatile Masses -aneurysms & pseudoaneurysms. Arteritis . Arterial–venous fistulas (AVF). Blue Toe Syndrome. |
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Term
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Definition
Structures that extrinsically pinch or constrict arterial flow. Popliteal artery entrapment(claudication-like symptoms). Nutcracker syndrome:renal vein. Median arcuate syndrome:celiac axis. SMA syndrome:SMA. Thoracic outlet syndrome:subclavian or axillary artery. |
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