In my last blog, I described how ultrasound is the imaging modality of choice for diagnosing tendon pathology. However, there are many limitations to using ultrasound including difficulty in objectively measuring changes in a tendon over time. Recently, a new imaging modaility called Ultrasound Tissue Characterisation or UTC is being used to monitor tendon changes over time. Advantage of UTC over ultrasound is the ability to objectively quantify the state of tendon structure AND to reliably follow these changes over time. It could revolutionise how we manage tendon injuries in the future.
I've attached an image of the UTC set-up below. The system is entirely portable, so I'm able to use it at Wasps rugby and my private consulting rooms.
UTC was devised by a Dutch veterinarian, Professor Hans Van Schie in conjunction with a group of smart Dutch engineers. Originally used on racehorses, its use has moved into the realm of human tendons. UTC uses a special tracking device to collect a series of ultrasound scans that are combined to form a 3D image. It then uses a special algorithm to define tendon structure integrity into 4 different types :
- Type 1 is generated by intact collagen fibres and is represented by green
- Type II is generated by swollen or wavy fibres and is represented by blue
- Type III is generated by disorganized fibres and is represented by red
- Type IV is generated by disintegration of fibres and is represented by black
Images of an elite track and field athlete who had Achilles tendon pain are attached below. The first image is an abnormal 2D ultrasound revealing darkened changes on the inside of the tendon consistent with tendonopathy. The second image is the UTC image revealing type 1 (green) and 2 (blue) echopixels on the outside of the tendon but type 3 (red) echopixels on the inside of the tendon. Red changes correlate with the darkened changes on ultrasound.
Colour coding of the tendon allows a much more objective assessment of the integrity of the tendon. Percentages of each type can be measured allowing for a more objective measurement of tendon integrity compared to ultrasound. I've attached a tendon report on a patient who had Achilles tendon surgery. Note the UTC assessment and graphing of percentage of echopixels.
As UTC objectively quantifies the integrity of a tendon, its strength lies in its ability to monitor changes during rehabilitation or treatment (normal ultrasound fails to detect changes as accurately). In addition, it may be useful as a screening tool for a group of athletes to detect early changes in a tendon before symptoms occur. Just like in racehorses, we might be able to act on early deterioration of tendon integrity seen on UTC and prevent lost time from tendon pain or rupture.
One obvious question is whether UTC imaging could change the way we practitically manage tendon injuries especially in the Achilles. Can UTC optimise the way we manage our patients? In next week's blog, I'll discuss a practical way UTC is changing the way we manage plantaris-asscoiated Achilles tendinopathy.