Two Tips to Learn Optimization Skills

1. Check out your machine’s manual! The machine might even have optimization guides! You can often search the manual by clicking the F1 button on the machine.
2. Play! See what happens when you push each button! Try the different settings under different types of scans.

Different brands of machines will have different trademarked names for similar functions with different patented technology; for example, GE has SRI (speckle reduction imaging) whereas Philips has XRES (eXtended Real-time Enhancement System [GE Healthcare, 2012; Jago, Collet-Billon, Chenal, Jong, & Makram-Ebeid, 2002]). The effects remain similar unless a brand has a technology that others do not yet have.

B-mode Optimization

1. Ensure a consistent shade of gray from near to far fields.
2. Watch for shadows, reverberation, haze, and other artifacts that degrade the diagnostic quality of the image (hide too much tissue) or make areas look like pathology.
3. Utilize your entire sector width by not cutting off one side of an area of interest while having empty space on the other side.

Color Flow Optimization

1. Vessels should be as consistent shade of blue or red as possible.
2. Fill the entire color box with color unless pathology interrupts the area.
3. Do not blossom the color outside of the vessel.
4. Do not post-process color flow gain.

Pulse Wave Optimization

1. Clearly show the top and bottom of the waveform by having scale (top of waveform) and baseline (bottom of waveform) set so that there is a small strip of black above the tallest peaks and a small strip of black below the lowest valleys. This is how we zoom in on the velocity measurements, ensuring the most accurate measurement possible.
2. Set gain to show the waveform without showing unnecessary noise (echoes within spectral window and around the spectral line unless necessary for very low flow states).
3. Do not post-process pulse wave gain. This will falsely change the peak velocity location.
4. Spectral window should be clear unless the vessel truly has low flow during systole.
5. Sample gate MUST be in the absolute center of the vessel (think all three planes, not just the two you can see in the image).
6. Angle MUST be parallel to the vessel walls (or parallel to blood flow if flow direction is not parallel with the vessel walls). We are measuring the blood flow, not the vessel.
7. Measure when at least three consecutive high quality cycles are obtained; do not measure directly after an arrythmia; try to not measure in an area of tortuosity (think velocity increases due to rollercoaster dynamics instead of stenosis).
8. If serially evaluating flow velocities in a vessel, the recommendation is to maintain a similar Doppler angle between studies. This angle is usually set as 45-60 degrees (Oates et al., 2009; Tola & Yurdakul, 2006).
9. Beam steering lowers velocity measurement accuracy. Rocking to obtain the required angle is ideal when feasible (Campbell et al., 2020; Oates et al., 2009; Russ et al., 2023; Steinman et al., 2005).
10. Know where to measure (see the following definitions and explanations).

Pulse Wave Optimization: Knowing the Anatomy of the Waveform

Knowing the anatomy of a spectral analysis waveform is important for four primary reasons:

1. Know if settings and technique are accurate
2. Know where to measure
3. Know what you are scanning (ECA vs. ICA, IVC vs. Aorta, etc.)
4. Know how to describe your findings

Arterial Anatomy

This is the physiology that causes the waveforms in the arteries that we record. Our lowest valley, end diastole, which we measure, is just before the systolic upstroke. End diastole corresponds to the lowest pressure in the arteries which happens when the aortic valve opens. Then the pressure increases in the arteries as blood flows into the aorta. We see the dicrotic notch, the dip in pressure when the aortic valve closes. Finally, pressure in the arteries falls as blood flows out of the aorta. All of the arteries we assess branch from the aorta; therefore, all of their waveforms are dependent on the pressure in the aorta.

This image depicts the cardiac cycle from an electrocardiogram (ECG) tracing in a common carotid artery waveform in relation to the timing of the cardiac cycle in the heart (seen in green below the spectral waveform). From one peak to just before the rise of the next peak is a single cardiac cycle in each line. The heart pumps the blood out into the aorta, then we see the fill into the artery.

Venous Anatomy

Organs

Peripheral

1. Spontaneous (calf vessels might be less so)
2. Phasic
   1. Lower extremity venous (LEV) increase with expiration
   2. Upper extremity venous (UEV) increase with inspiration
3. Vary in pulsatility
   1. UEV more pulsatile
   2. LEV some pulsatility may be normal but often indicates pathology
4. Not continuous
5. Will augment with compression or release of Valsalva
6. Do not show reflux with Valsalva

See the UEV and LEV Protocols for examples!

Know What You are Scanning

You can use your knowledge of arterial versus venous waveforms to help you determine which vessel you are interrogating. Additionally, knowing the differences in normal internal carotid artery (ICA) and external carotid artery (ECA) waveforms can help you distinguish which one you are in before you even take your first B-mode image (these are tricky at first). You can “drop a dirty Dop” and use PW without optimizing to get a quick sample of the waveform to determine what the vessel is without the intention of taking any spectral images yet. Use the Doppler as a tool, not just one more picture you have to take in your protocol. Remember too, color is also your friend! Try keeping CF on as you sweep from ICA to ECA and lengthen them out. The vessels are much easier to appreciate all lit up than darkened!

Know if Settings and Technique are Accurate

Now that you understand the anatomy of the waveform, you can appreciate if you need to adjust your technique and/or your settings. The first thing we should always ensure is that we are in the absolute center of the vessel that we are interrogating. This means not only in the center of the two planes that we can see (top-to-bottom and side-to-side), but also that pesky third plane that we cannot see! How can we tell if we are where we are supposed to be? We clear out our spectral window by tipping the top of the probe through the elevational plane (do this maneuver before adjusting gain: not only will you clear out the window, you will get a brighter, stronger spectral intensity. You will be more diagnostically accurate). Once your technique is accurate, ensure your settings are correct: baseline, scale, and gain must all be optimized properly so that your measurements are correct.

Know Where to Measure

There is a surprising amount of confusion about this amongst professional sonographers. You, however, will know the accurate way to measure because you understand the anatomy of the waveform and what your measurements mean.

Several studies define and describe peak systolic velocity (PSV) and end-diastolic velocity (EDV), including Chavhan et al. (2008), Kim et al. (2020), O’Shea et al. (n.d.-a), O’Shea et al. (n.d.-b), and Pellerito and Polak (2012). PSV is the tallest peak anywhere in systole. EDV is the velocity just prior to the next systolic upstroke.

PSV: The highest spot along the length region of the spectrum which correlates with the systolic phase of the cardiac cycle.

EDV: The EDV corresponds to the point marked at the end of the cardiac cycle (just prior to systole).

Peak Velocity (PV): The maximum positive Doppler shift during a cardiac cycle, used for portal veins (Gallix et al., 1997).

Know How to Describe Your Findings

The terms used to describe vascular ultrasound findings are standardized by the publication by Kim et al. (2020). This is a richly-illustrated article that I strongly recommend that you obtain for your reference.

1. Arterial
   1. Flow Direction
   2. Phasicity
   3. Resistance
   4. Other terms (upstroke descriptors, sharp peak, spectral broadening, staccato, dampened, flow reversal)
2. Venous
   1. Flow direction
   2. Flow pattern
   3. Spontaneity
   4. Other terms (augmentation, reflux, fistula flow)

To Increase Sensitivity

1. Decrease scale (PRF).
2. Turn up CF/PW gain, power.
3. Reduce F for penetration; Increase F for F_Dop.
4. Turn down B-mode gain (Threshold).
5. Reduce threshold.
6. Reduce wall filter.
7. Use accumulation.
8. Use power Doppler.
9. Use CW.

To Improve Color Resolution

1. Use correct box location for focus.
2. Increase color packet size (Color packet size↑=↑SNR).
3. Increase line density.
4. Use frame average.
5. Wall filter reduces flash artifact and slow flow.
6. Flash suppression reduces flash artifact.
7. Use spatial filter.
8. What affects spatial resolution of color flow? Line density and Frequency.

Artifacts

An artifact in ultrasound is something false in our image: a shadow, a brightness, an echo, etc., that does not reflect what is really in the body.

Sometimes artifacts are actually helpful.

A lot of our optimization work is to work around and/or eliminate artifacts to make sure that what we are seeing, and what we are showing our reading physician, is real.

Accidentally showing an area and making the area appear to have pathology is surprisingly easy.

Costly additional imaging may be ordered for a patient because a renal cyst was not properly cleared out during the survey images.

A patient may be sent to surgery because the CBD during a challenging emergency room (ER) scan was not cleared out.

Knowing your artifacts, knowing how to determine if what is being seen is indeed an artifact and not real, and knowing how to eliminate unwanted artifacts from your imaging is paramount.

Baad et al. (2017) provide a comprehensive and well-illustrated review of ultrasound artifacts that serves as a highly valuable reference for sonographers.

Combining Optimizations & Accurately Documenting Pathology

1. Show in Survey Images
2. Long
3. Trans
4. Measure
5. Color
6. Spectral

• When we identify pathology during the survey, we note to ourselves the two largest and most concerning representations of a single disease process. Then we document.
• Be sure when you do your survey of the organ you show the area of interest (AOI) in your sweep in both long and transverse planes. Show the area(s) in relation to major vessels whenever possible.
• Then show the AOI optimized: write zoom in*, frequency as high as possible*, speckle reduction*, edge enhancement, frame average, etc. (*Always do). Find the longest dimension for long, turn 90 degrees and document trans. Label long and trans relative to where they are in the sweep; i.e., Long Uterus LT and Trans Uterus Mid.
• Measure including any surrounding halo or capsule. Color can help identify borders.
• Scale down and gain up appropriately for color. Sweep through the AOI in two planes with color on to find relevant flow patterns. Remember that angles matter. Try PDI. Color patterns can help differentiate between concerning or likely benign growths (for example, liver focal nodular hyperplasia versus a liver adenoma). If you are scanning a superficial area, such as in the breast, subcutaneous tissue, or skin, lighten up pressure so that you do not compress small vessels.
• Doppler any significant vessels to determine low or high resistive patterns.
• For vascular studies, be sure to walk your Doppler gate through any areas of stenosis to find the highest velocity. Also document waveforms pre- and post- stenosis. Document plaque clearly.
• For vascular studies, when evaluating stents and graphs, be sure to document velocities pre-, proximal, mid, distal, and post- the intervention.
• Check out pancreas, liver, renal, female pelvis, scrotal, thyroid, and mesenteric Doppler for examples of pathology!

Guide to Color Box Steering with a Linear Probe

This concept is very confusing at first. If you are ever unsure, put pulse wave on and you will see the correct way the angle should be and the corresponding box steering. The box should be angled the same direction as the vessel.

Guide to Determining Blood Flow Direction

Linear Probe

The color flow legend on the side of the screen shows what color is flowing toward the transducer (top color) and which is flowing away from the transducer (below the baseline). Which side is the transducer? The transducer side of the color box is the same side as the acute angle: you can draw a straight line down and stay outside of the box. You will often find pathology, collaterals, grafts, and unusual situations in which you have to determine blood flow direction, and this can get very confusing in the moment!

Curved Probe

The transducer is considered the line within the color box that is perpendicular to the vessel. You can window, angle, and rock the transducer so that the entire length of vessel is traveling toward or away from the transducer.

Guide to Clearing Out Vessels & Other Cystic Structures including Gallbladder & Bladder & Cysts

Artifact in vessels, the gallbladder, bladder, and even cysts looks like pathology: clot, plaque, solid lesions, etc. You have to clear the noise out, and no, TGCs are NOT the answer! The best optimization keeps the real echoes of the surrounding tissues, maintaining a consistent shade of gray from superficial to deep.

1. Tip the top.
2. More pressure (less distance) or less pressure (create more distance).
3. New window: angle through more tissue or another structure such as internal jugular vein (IJV) or liver.
4. Increase frequency.
5. Increase speckle reduction imaging.
6. Decrease overall power/gain.
7. Increase compound imaging, frame averaging, line density.
8. Create more distance with a standoff pad of gel (especially helpful for very superficial cysts or very skinny patients).

Guide to Palpables & Superficial Scans

I learned how to scan lumps when I was studying to scan breasts with precision. The best resource for studying for breast ultrasound, hands down, is Breast Ultrasound by Dr. Anthony Thomas Stavros (2004). This doctor is brilliant and has made tremendous contributions to the world of ultrasound. When you have to learn to scan hernias, obtain his article that is complete with cine clips (Stavros & Rapp, 2010). Even in researching morphology of arterial waveforms, his name as an expert investigator appears (Stavros et. al, 1992).

Echopalpation is a technique in which the sonographer scans (echo) the area while the area is being palpated either by the sonographer or the patient. This is an important step to utilize in scanning palpable areas—just because an area might be seen where a patient says they feel an area does not mean that area is the area that they are feeling. Furthermore, oftentimes an area of normal anatomy can cause a prominent lump for a patient. Certain areas of adipose tissue like to be what I lovingly refer to as little divas. By using this technique, we can show the patient that what they are feeling is being shown on the screen. We can correlate normal anatomy with what they are feeling and reassure them that what is being felt is normal, though lumpy, tissue. Additionally, the fingers palpating the superficial lump create a base to rest the probe and a pocket where we can fill the area with gel, creating a steady standoff pad. This is important to localize the area at the elevational focus which is typically 1.0 cm deep. The skill to use this technique takes practice but is an invaluable tool. Although this is a widely used technique, I personally learned the skill from Dr. Stavros’s book and feel indebted to him for the guidance (2004).