Tips for Clinical
Practice
How to choose the optimum ultrasound machine for neuromuscular ultrasound?
Here, we will answer 3 commonly asked questions by novice sonographers about the appropriate ultrasound machine for neuromuscular applications.
Q1. Should I purchase a high-quality machine or a medium quality cheaper machine?
High-quality machine is always better for beginners to enhance the skills and to accurately identify pathologies. Moreover, High-quality machine is a much better investment on the long run. A way to decrease the cost of high-quality machine is to share its purchase with trustable colleagues, or you have also the option to buy refurbished machines.
Q2. Should I buy a console or a portable machine?
Console machines are more suitable for insititutions & hospitals because they can be more durable. Usually console machines have better image quality than portable because they have more powerful processors, but nowadays, there are excellent high-quality portable machines.
Portable machines are more suitable for personal use especially if you intend to move from one workplace to another or intend to give home visits to the patients.
Q3. What is the optimum probe type for neuromuscular ultrasound applications?
* A linear wide-band probe is a must.
* Additional curvilinear probe is optional but of course will be beneficial to get if your budget allows. If the budget doesn’t allow purchasing it, then it can be postponed later, and you can manage with the wide-band linear array transducer in the majority of cases in addition to using the trapezoid-view that is available in all machines.
* High resolution is a must for NMUS. thus, probe frequency 18 MHz or higher is the best for superficial structures, but some 16 MHz probes give also very good resolution because resolution is not only about frequency.
How to optimize ultrasound image for nerve scanning?
There are basic parameters that you must adjust to obtain the best nerve and muscle image. These are the frequency, depth, focal point position, gain, and time-gain compensation.
A common approach is to follow 5 sequential steps:
1. Choose the appropriate frequency according to the target structure depth, and the patient’s characteristics.
2. Adjust the depth: its adjustment depends on depth of the target structure and the aim of scanning.
3. Adjust the focal point: very important to improve the lateral resolution. The focal point should be adjust at the level of target nerve or just at its lower border.
4. Adjust the gain so that there is good distinction between the nerve & its surrounding structures or between the muscle and the surrounding connective tissue/septum.
5. Adjust time gain compensation (TGC) if needed.
More knobs and other parameters may need adjustment to further optimize the image. The best way to learn how to do that is on the US machine during a demo session… So, join us at one of our basic courses during which we teach these techs in detail.
Few Scanning Tips ..
* Always scan the nerve/muscle in two perpendicular views.
* Avoid slow tracing.
* Tracing is all about visual tracking of the target nerve/muscle on the screen.
* Avoid exerting excessive pressure by the probe.
* Always keep the probe orthogonal to the target nerve/muscle.
* Do not forget that you may need to re-adjust frequency, depth, and focus as you trace the nerve from one level to another along its course.