When you first start scanning, one of the most difficult things to pick up is how to orientate yourself to an MSK ultrasound image, and working out what on earth you are looking at! I remember standing around watching my colleagues scan, saying ' yeah, mmm, yup, interesting' all noises of agreement whilst not having the foggiest idea what I was looking at!! It is not easy, and at least with an MRI or x-ray it kind of looks a bit like a leg or an arm..with ultrasound it just looks like a stormy sky! This initial learning is something that can be easily forgotten once you become more competent at generating images, it becomes second nature. So this post serves as the start of a few articles around the basic skills to utilise ultrasound.
I thought I would write this article to provide some basic pointers on how to interpret an ultrasound image.
The terminology is often confusing and it might be useful at this point to consider those classic diagrams which we all often encounter when we start our training..such as the one below.
Sonographers often talk about their images in either the transverse or the longitudinal plane, or to confuse matters further..the short or long view. It is of fundamental importance that you understand what you are looking at and what this jargon means!
Longitudinal or long view
Lets start with the longitudinal view, which and may be termed a sagittal view in other forms of imaging. Below is a longitudinal view of a patella tendon, attaching to the tibial tuberosity. This is a slice through the patella tendon as if you were looking at it from the side.
Transverse or short view
The transverse or short view..the easiest way to conquer this view is to think of a a cross-sectional view looking up/down the structure. For example, take the achilles tendon as an easy example. The image below is a transverse slice of the achilles and you are looking directly through the different fibres in a cross-sectional/transverse plane or short view.
So why do we both to take both longitudinal and transverse views. Well we don't always, and certainly with some MSK structures it is not common place to always interrogate with both a transverse and longitudinal view. For example, the common extensor tendon at the elbow is rarely viewed in a transverse view, and the reverse is true for the subscapularis which is not often viewed transversely. It is however good practice to look at both views to improve the accuracy of your images. We know that ultrasound is highly user dependent , and subtle changes in angulation of the probe can lead to very different conclusions and artefacts such as anisotropy. If you are therefore suspicious of for example a tear of a tendon it is good practice to convince yourself with both a longitudinal and transverse view.
As always, please comment and post your thoughts on this article or the topic in general!