Vascular - Test 1 (Jo's set)

Where is the transtemporal window located (TT)?

1. Over temporal bone

2. Superior to zygomatic arch

Which vessels can be identified from the transtemporal window (TT)?

1. MCA

2. ACA

3. PCA

Where is the transorbital window located (TO)?

Through eye

Which vessels can be identified from the transorbital window (TO)?

1. ICA siphon

2. Ophthalmic (OCA)

Where is the suboccipital window located (TF)?

1. Through foramen magnum

2. Back of head

Which vessels can be identified from the suboccipital window (TF)?

1. Vertebral arteries (VA)

2. Basilar artery (BA)

What is included in the vessel identification for the MCA?

1. SV Depth = 30-60 mm

2. Flow Direction = Towards (ante) transducer

3. Mean Velocity = 55 cm/sec

What is included in the vessel identification for the ACA?

1. SV Depth = 60-80 mm

2. Flow Direction = Away (retro) from transducer

3. Mean Velocity = 50 cm/sec

What is included in the vessel identification for the PCA?

1. SV Depth = 60-70 mm

2. Flow Direction = Towards (ante) transducer

3. Mean Velocity = 40 cm/sec

What is included in the vessel identification for the ophthalmic artery?

1. SV Depth = 60-80 mm

2. Flow Direction = Towards (ante) transducer

3. Mean Velocity = N/A

What is included in the vessel identification for the vertebral arteries?

1. SV Depth = 60-90 mm

2. Flow Direction = Away (retro) from transducer

3. Mean Velocity = 38 cm/sec

What is included in the vessel identification for the basilar artery?

1. SV Depth = 80-120 mm

2. Flow Direction = Away (retro) from transducer

3. Mean Velocity = 41 cm/sec

What is included in the vessel identification for the temporal ICA (TICA)?

1. SV Depth = 55-65 mm

2. Flow Direction = Towards (ante) transducer

3. Mean Velocity = 40 cm/sec

When does crossover collateralization occur in the transcranial system?

When antegrade flow is demonstrated in ipsilateral ACA

When does ECA to ICA collateralization become evident?

When there is retrograde flow in ipsilateral ophthalmic artery

When does posterior to anterior collateralization become evident?

When ipsilateral PCA flow velocities exceed ipsilateral MCA flow velocities

Which vessel(s) is the most accurate way to diagnose an occlusion?

1. MCA

2. ICA

Which vessel(s) is the most accurate way to diagnose a vasospasm?

MCA (important for endarterectomy)

What is a pressure gradient?

Difference in pressure between two points of a vessel that creates flow

What is potential energy?

Stored or resting energy resulting from an object’s position (pressure)

What is the main form of energy present in flowing blood?

Potential energy as blood flow is influenced by cardiac output and hydrostatic pressure

What is kinetic energy?

Energy of motion or ability of blood to do work (velocity)

What is hydrostatic energy or pressure (gravitational energy)?

Effect of gravity on circulatory system

What is the total composition of blood determined by?

Sum of potential, kinetic, and hydrostatic energy

What is pulse wave?

Short bursts of sound produced by electrical impulses applied to transducer

What are the components of pulse wave?

1. Acceleration

2. Peak systole

3. Deceleration

What is laminar flow?

Flow that travels in concentric rings or layers

Where is the fastest flow in a vessel with laminar flow?

Center of vessel

Where is the slowest flow in a vessel with laminar flow?

Periphery of vessel due to friction from vessel walls

What is turbulent flow?

Flow that travels in many directions and speeds causing mixing of blood layers

Where does turbulent flow occur most often?

Distal to stenosis

What is viscosity?

A measure of a fluid’s resistance of flow

What is considered the thickness or density of a fluid ?

Viscosity

What is inertia?

A measure of resistance to acceleration of an object

What is Reynolds number?

Expresses likelihood of turbulence

What Reynolds number indicates turbulent flow?

2000 (HIGH REYNOLD’S NUMBER)

What is the Reynolds number equation?

What is Poiseuille's Law?

Formula that corresponds to changes in flow with changes in pressure, radius, length, and viscosity (volumetric flow rate)

When can we apply Poiseuille’s law?

Straight, rigid tube with laminar flow

When can we NOT apply Poiseuille’s law?

Stenosis

What is Poiseuille’s Law equation?

What is Bernoulli’s Principle?

Total fluid energy is a balance between potential and kinetic energy

What is Bernoulli’s Equation?

Where there is a decrease in pressure in regions of high flow speed (velocity)

What is volumetric flow rate (Q)?

Flow is quantified by volume that passes by any given point per time

What is the volumetric flow rate equation (Q)?

According to the continuity rule, volumetric flow rate must be… proximal, within, and distal to a stenosis

Constant

What is resistance?

Opposition of flow

What is the resistance equation?

What is resistance is dependent on?

1. Length

2. Viscosity

3. Lumen

When does flow occur in vessels with HIGH resistance?

ONLY during SYSTOLE

When does flow occur in vessels with LOW resistance?

Throughout cardiac cycle (systole and diastole)

What is spectral broadening?

Filling of spectral display waveform

What is a spectral envelope or window?

Clear region within waveform under systole

What do the darker colors mean on an ultrasound?

Slow flow

What do the lighter colors indicate on an ultrasound?

Fast flow

What is the gold standard for imaging the cerebrovascular system?

Cerebral angiography (arteriogram)

What is cerebral angiography or an arteriogram?

Imaging that uses contrast medium and fluoroscopy (x-ray) to visualize carotid and intracranial vessels

Identify this image.

1. ICA

2. ECA

3. CCA

Identify this image.

ICA occlusion

Identify this image.

ICA occlusion

Identify this image.

Left CCA occlusion

What is OPG-GEE?

Test used to detect ICA lesions by identifying changes in ophthalmic blood flow volume

What is the normal value for OPG-GEE?

> 0.4

What are the advantages of carotid duplex scanning?

1. Identifies exact location carotid disease

2. Documents and follows disease progression

3. Provides plaque surface contour information

4. Estimates severity of disease

What are the limitations of carotid duplex scanning?

1. Shadowing from calcs prevents visualization and Doppler analysis

2. Artifacts from plaque cause overestimation of disease

3. Underestimation of disease occurs when soft plaque accumulates, poor Doppler angle used by tech, sonographer error in missing high velocity areas of flow

What percentage of people have their ECAs in the near field or anterior?

95%

What percentage of people have their ICAs in the near field or anterior?

5%

Identify this image.

Right CCA

Identify this image.

A. Right ICA

B. Right ECA

Identify this image.

Left CCA

Identify this image.

A. Left ECA

B. Left ICA

What are the defining sonographic characteristics of the ICA?

1. Larger than ECA

2. NO branches seen on US

3. Low resistive waveform

What are the defining sonographic characteristics of the ECA?

1. Smaller than ICA

2. Branches seen on US

3. High resistive waveform

Identify this image.

A. ECA

B. ICA

Identify this image.

A. ECA during diastole

B. ICA during diastole

Is the color box steered the correct way?

NO

Is the color box steered the correct way?

YES

Identify this image.

Vertebral artery

Identify this image.

Distal vertebral obstruction

Identify this image.

Proximal vertebral obstruction (tardus parvus)

Identify this image.

Subclavian steal seen as retrograde vertebral flow

The Doppler angle should be…

Less than 60 degrees (40-60 degrees)

What does MI stand for?

Myocardial infarction

What does DM stand for?

Diabetes mellitus

What does hypertension (HTN) mean?

High blood pressure

What does PAD stand for?

Peripheral arterial disease

What is the ICA bulb?

Normal dilation of CCA at bifurcation or proximal ICA segment

What is plaque?

Atherosclerotic disease within arterial walls

What is morphology?

Shape and appearance

What is a lumen?

Inside dimension of an artery

What is infarct?

Tissue death caused by a lack of oxygen

What is a collateral vessel?

Vessel that carries flow to compensate for an obstruction in primary source vessel

What does contralateral mean?

Opposite side

What does ipsilateral mean?

Same side

What does anomalous mean?

AKA anomalies or deviation from normal

What is a cerebrovascular accident (CVA)?

Stroke that can cause permanent or semi-permanent impairment

What is a transient ischemic attack (TIA)?

Stroke with symptoms that resolve in 24 hours

What is a reversible ischemic neurologic deficit (RIND)?

Stroke with symptoms that resolve completely within three weeks, but not within 24 hours

What is the most common type of stroke?

Transient ischemic attack (85%)

What is the incidence rate of new strokes per year?

80,000 (up from 500,000 10 years ago)