Ultrasound is the eyes of vascular practitioners, facilitating success in every Phlebology practice worldwide. For a vascular technologist, a comprehensive understanding of the ultrasound system will add tremendous value via image optimisation, which allows for complete diagnostic confidence in the ultrasound findings, acquisition of appropriate candidates for intervention, and development of an effective treatment plan.
It is crucial to consider each component of the ultrasound system in order to achieve each of these goals and, ultimately, streamline the Phlebology
A comprehensive understanding of the various types and functions of ultrasound probes offered with the ultrasound system is the vascular technologist’s- and by extension the Phlebology practice’s- primary step to success. Ultrasound probes act as an arrow in the diagnostic process, allowing the technologist to change the frequency of the sound-waves in order to penetrate at different depths into the body for optimal image acquisition. The standard linear array transducer should be lightweight and vary from 7-12 MHz in frequency, which corresponds to a penetration depth of one to seven centimetre, respectively. If the Phlebology practice has a disproportionate demographic of obese patients, it would be advantageous to purchase a curved array transducer, which ranges in frequency from 2-6 MHz, permitting a penetration depth as high as 16 centimetres.
The secondary core concept that the vascular technologist must familiarise themselves with is the basic controls of the ultrasound system. Basic controls include overall gain, time gain compensation, focus, and auto tissue optimisation. The overall gain control function allows the vascular technologist to adjust the brightness of the image uniformly. Time gain compensation (TGC) adjusts gray shades in a particular section, allowing optimal images at varying centimetre depths. Focus allows enhancement of visualisation at the depth of interest. Finally, auto tissue optimisation (ATO) allows adjustment of the gray shade contrast of the overall image. It is recommended to seek ultrasound manufactures offering tissue harmonic imaging as a standard option, which will enhance and optimise the body tissue while simultaneously decreasing artefact.
Beyond the basic controls, varying settings of ultrasound imaging must be considered. Grayscale imaging, or B-mode, is a setting that will uniformly provide superior penetration. Dynamic range compression will assist in producing a clear image with high contrast and fewer shades of gray. It is important that grayscale imaging has equivalent sensitivity in order to visualise the vessel walls with clarity. If optimised correctly, this setting should produce an image that is pleasing to the eye- not too smooth, too soft, or too gritty. The ultrasound system also provides different gray shade maps for the vascular technologist to select for optimal imaging at any given point during the ultrasound exam. When a gray shade map is selected, the system automatically adjusts for overall gain, dynamic range, and time gain compensation. The next setting that requires consideration is colour flow. Color flow should never attenuate the grayscale image after utilisation. An experienced vascular technologist will ensure that colour flow is well-balanced, finding the middle group between excess and deficiency. In order to pinpoint the perfect amount of colour, the ultrasound system should have colour flow mapping options with easy-to-adjust colour scale settings ranging from eight to fifteen. This feature is particularly imperative when dealing with veins, which are characterised by low blood speed and require minuscule adjustment in order to achieve diagnostic accuracy.
The final setting that requires consideration is pulsed-wave Doppler. This setting is used to identify the location of blood flow, quantify blood flow, assess patency, and measure resistance. In order to optimise the pulsed-wave Doppler waveform, the vascular technologist must familiarise themselves with tools that include, but are not limited to, pulsed-wave Doppler frequency, compression, and the reject button. Adjusting pulsed-wave Doppler frequency can increase or decrease the spectrum strength of the waveform. Adjusting the compression can increase or decrease the brightness of the waveform. Finally, utilising the reject button sharpens the spectrum of the waveform image while removing low-level gray echoes.
In conclusion, the secret to having a successful Phlebology practice is not all the bells and whistles that the ultrasound manufactures will inevitably attempt to sell you. While these optional features may increase convenience, the actual secret is a comprehensive understanding of how to optimise every ultrasound image using the standard tools that are offered by every manufacturer. The aforementioned consideration of proper probe selection, mastery of basic controls, and utilisation of proper imaging settings leads to effective image optimisation, which subsequently leads to a streamlined Phlebology practice.
Julie A. Cardoso RVT, RPhS, RDCS
Eduard Marmut Universal Ultrasound Management www.universalultrasoundmanagement.com