There are two main uses for the split-screen technique, and within each of those a number of variants. The two main purposes for this technique would be:

  1. Comparisons — comparing one thing versus another, in one image.
  2. Extensions — capturing one long image, of more than one probe length.

 

Comparisons

These are the most obvious: you could compare, for instance, the left foot versus the right foot, side by side, in one image. Or you could present the state before versus during a guided injection. Or you could show a longitudinal scan and a transverse scan of the same pathology, side by side, in one image.

You could, of course, accomplish the same thing by capturing two separate images. But using the split-screen technique (explained below) allows you to get them both on one screen, in one image, annotated side-by-side. This can sometimes be quicker, not to mention more visually clear if the contrast is between the two is significant.

 

Extensions

The split-screen technique can also be helpful when trying to view an extended image (that is, longer than one probe length). For example, let’s look at capturing up to 100mm of the fascia — all in one image.

We will use this extended-imaging of the plantar fascia as our example in outlining how the technique is performed.

Using the split screen function at first seems a little cumbersome, but only the first two or three times you play with it. After a few exams, the technique becomes much easier, and it can be helpful not only in comparisons (one foot vs. the other, side by side on the screen; or even the same foot but scanned along one plane vs. another), but also in extensions: where, for example, you capture one part of the plantar fascia on the left and the continuation of it on the right, giving you a longer scanned area.

Here is the best technique I have worked out for using the split-screen function, whether on the CTS-5500 or the CTS-7700:

 

1.) Before starting, make sure your settings are the way you want them: frequency at 7.5 MHz, Depth at 6.3 (or perhaps even better in this case, at 4.7), your focus pointers about 2 or 3 centimeters down. Also make sure your orientation dot is at the top left of your screen (in the top left corner of the image, just below where your practice name appears). If it is on the right side of your screen, press the "L/R" button on the right-hand side of your console to switch the dot over to the left. You will orient your probe longitudinally, keeping the bump (or "notch") on your probe pointing toward the toes, orienting it to the dot on the screen.

 

2.) With a live image on the screen (it should say "Focus" at the bottom right corner), press "B Mode" to engage the split screen, giving you a live image on the left half of the screen.

 

3.) Briefly scan until you find the band of the fascia you are targeting, approximately two probe lengths from the calcaneus. Do not worry at all about the quality of the image as yet, simply get an idea of where the fascia lies and what angle you are going to want to be at, and then turn the "Display Select" knob one notch in either direction (the first knob on the left of your console) to freeze that first image on the left half of the screen and bring up a live image on the right side of the screen. This is where you will really begin scanning.

 

Initial Scan

 

4.) With the right half of the screen now live, simply scan as you normally would. Come over the calcaneus and watch for the fascia to spread out from there, adjusting your settings as needed. Correct your angle if necessary and repeat the pass over top of the calcaneus several times, until you get a clear image of the leading edge of the plantar fascia beyond the calcaneus.

 

Origin

 

5.) This is the important bit. Assuming that you don’t simply want to capture a comparison, with one foot on one half of the screen and the other foot on the other half, what you will do now is execute "the move." Here it is: Once you get the image you like on the right half of the screen, turn the "Display Select" knob one click to freeze the right side of the image and activate the left again. Observe where the leading edge of the probe stops (perhaps even mark the point with your left hand) and lift the probe and place it end-to-end with that point, giving you the rest of the fascia on the left side of the screen, taking over where the first probe stopped and creating one continual image of the fascia. Be sure to preserve (or correct) the angle, and try to line up the two images so they match up neatly. When they do — press "Freeze."

 

The move

 

You now have two frozen images on the screen, side by side, forming one complete image. Note that at this point, if you wish to correct either half of the image, you can use the "Display Select" knob to toggle between live imaging on the left or live imaging on the right, freezing whichever side you toggle away from. Indeed, sometimes going back and forth can be helpful, first scanning from the calcaneus on the right, then over the middle of the foot on the left, or scanning the mid-foot and then freezing the left side of the screen while sliding back toward the calcaneus and pressing "Freeze" on the right side. With a little practice you will develop your own technique.

 

Diagrammed

 

Once you have a complete image, you can make your measurements and annote it as normal, and then print or save the image.

Getting Out of Split-Screen Mode

When you are done and have printed or saved your image and wish to go back to normal live imaging, you will need to "clear" both sides — which can be a little tricky the first time you do it. Here is how: With either side selected, press "Freeze" to un-freeze that half of the image. Now turn the "Display Select" knob to unfreeze the other side. Now press "B Mode" twice to bring the normal view of the image back around. And that’s it!

 

Give this a try. And email me some of your results (to shawn@fisherbiomedical.com). I would love to see what you come up with.