Category Archives: Tips and Tricks

Equipment, Tips and Tricks

Image Optimization

Depth, Focus, Gain

When it comes to image quality, if you follow these easy steps for every image, you can’t go wrong! First, adjust your depth. Is the structure you are imaging, say the aorta, way at the top of the screen? Decrease your depth so your image ends just below the area of interest. Is the lower pole of the kidney cut off? Increase your depth to include a few centimeters below the kidney border.

Now that you’ve adjusted your depth, apply the focus! By tapping or twisting the focus knob, place your focal zone at or just below the structure of interest. This will place optimal resolution at the organ you want to see.

Finally, tweak the gain. Usually a dial on the main console, twist to increase or decrease the brightness of the image. Your goal: Make anechoic structures, such as vessels or the bladder black, but still bright enough to see surrounding structures.

With these three steps, your images will be picture perfect!

Articles, Critical Care, Emergency medicine, Internal Medicine, Tips and Tricks

POCUS pitfalls

It’s easy to get carried away when doing your own bedside ultrasound but it’s important to know your limits. Pablo Blanco and Giovanni Volpicelli have published an excellent article in Critical Ultrasound Journal 26 Oct. on some of the most common mistakes and pitfalls when performing point of care ultrasound. You can find it here.

Tips and Tricks

A Field Guide to Bedside Ultrasound – out now

We’re so excited! After a long gestation, our first book is finally out. It’s geared to those starting out in bedside ultrasound and offers a basic grounding in US technique. Concise and pocket-sized, it contains chapters on basic scanning of the most common applications such as scrotum, leg veins, abdomen, OB, lung and cardiac. Packed with tips and tricks it also has a chapter on US guided procedures and what to look for when buying your own machine. It’s available direct from our publisher or from Amazon. E-book versions are also available from iTunes and the Amazon Kindle store. To check it out, click on the link.

Abdominal, ED, Tips and Tricks

The Gallbladder

It’s Thanksgiving weekend, and what a fitting time to talk about the gallbladder. With the rich meals associated with the holidays, it’s no surprise that the emergency department fills with patients who have biliary tract disorders such as gallstones and cholecystitis.

Here are some tips on how to find the gallbladder on ultrasound. Begin with the patient supine, placing probe sagittally and to the right of mid-line. The image should show liver and the gallbladder. Often a held inspiration can help move obscuring bowel gas. Now often patients do not have a nice supine window, so next view to try is intercostal. Place the probe at right lateral position, scanning between the ribs. Next look at the gallbladder when the patient is in a left lateral decubitus position. Often this is the best view to look at the GB because the liver creates an acoustic window and the bowel moves to the left. Again, place probe subcostally, right of mid-line, and sweep with your probe in the sagittal position.

Below is an ultrasound image of a normal gallbladder. Stay tuned for further posts about gallbladder pathology!

normal-upper-abdominal-ultrasound-male-adult

Case courtesy of Dr Henry Knipe, <a href=”https://radiopaedia.org/”>Radiopaedia.org</a>. From the case <a href=”https://radiopaedia.org/cases/48019″>rID: 48019</a>

Tips and Tricks

Assessment is Key!

It cannot be stressed enough that the real shining star of ultrasound is the real-time assessment of a structure; the actual sweeping back and forth through the organ of interest. It can be all too easy for new scanners to focus on finding the organ and taking a picture of it. Don’t forget to sweep through that structure! Here’s a good example: When scanning a kidney in the sagittal plane, plant your probe and angle it side to side. As you sweep through the kidney, assess medial to lateral until you have scanned completely in and out of the kidney. You never know, you might pick up an exophytic cyst on the periphery of the kidney!

Don’t be discouraged if you aren’t getting textbook images at the beginning of your ultrasound journey, it’s the assessment that counts.

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Equipment, Tips and Tricks

Select the right probe

When you’re starting out with bedside ultrasound, it’s tempting to save yourself a few seconds and use the probe that’s set as the default probe for whatever you want to scan. This is a rookie error. The reason there are different probes is that any single probe design and its corresponding frequency range represents a series of trade-offs. The biggest trade-off is between resolution and depth of view. The other is between scope (the size and shape of the sound beam) and resolution. For more depth, for example to see the back of the liver, you need a lower-frequency probe but this limits the image resolution or detail that is seen. High-frequency probes are great for detail work, for example with tendons or vessels, but have limited depth of penetration and are therefore limited to superficial structures.

With scope, the wider or more fan-shaped the beam, the lower the resolution. The higher resolution seen with linear beam arrays comes with a smaller lateral field of view or scope.

Therefore when scanning abdomens, use the low-frequency, curved probe (good depth, wide scope, lower detail). When scanning superficial structures such as vessels or for foreign bodies, use the high-frequency, linear probe (shallow depth, high detail, narrow scope). When scanning the heart use the small-footprint, wide-scope probe with the lower frequency. This allows you to get between the ribs (small footprint) and see all the cardiac chambers (greater depth) but does compromise on the detail which is an acceptable tradeoff with cardiac sonography.

Internal Medicine, Tips and Tricks

Practice needle procedures

Practice your needle procedures on a home-made phantom. You can do it over and over again until you are really good at them and without hurting anyone. This sounds crazy and so very few people do it. Hence, very few get really good at needle guided procedures. This is exactly why you should do this. For a cool video on making a home-made ultrasound phantom for this purpose check out this link from Clarius.

Tips and Tricks

Optimize your image constantly – Focus

The resolution of the image generated by the ultrasound beam is not the same across all depths. The sound waves emitted from the crystal array in the probe can be focussed electronically at a level of your choosing, which you should adjust to the level of the organ of interest. This maximizes the resolution of the image at that depth. You should alter the focus level continuously during scanning as your target organ changes in depth.

When using ultrasound to guide needles in patients (for example when inserting a central line), set your focus at the level of your needle and not at the level of the target vessel. This will help you see the position of your needle more clearly.

Tips and Tricks

Optimize your image constantly – Gain

As you scan, structures of interest may dive deep in the body and will appear darker. You should increase the 2D gain control to compensate and keep your image bright enough to see clearly. When the structure becomes more superficial, you may need to decrease the gain to avoid a “white-out” of the structures of interest. Try and maintain your image in the middle of the grey scale to help different structures stand out from one another. This is called “maintaining image contrast”.

Some newer machines have an “auto-optimize” button which automatically adjusts the gain and maintains image contrast. You should push this button regularly during scanning and always after you change the depth of view.

Tips and Tricks

Optimize your image constantly – Depth of view

To get the best image quality, keep adjusting the depth of view as you scan.

As you move the probe over the patient, the organ or structure of interest will be constantly varying in depth on the screen and you want to keep this structure filling as much of the screen as possible to help you see the detail. Setting the depth too large results in shrinking the target structure to a small strip at the top of the screen while the lower screen displays useless information. Try getting into the habit of maximizing your screen resolution by filling your screen with the target.