Digital Ultrasound

Digital Ultrasound is the new “buzz word” in the veterinary industry. There is no real industry standard to what the term Digital Ultrasound stands for. To better understand what the term Digital Ultrasound means, here are some facts and frequently asked questions about Digital Ultrasound.  

FACTS:

• Digital comes from the word, DIGIT, and in the case of most electronic equipment is in the form of binary (which means ones and zeros). One is “on” and zero is “off”.

• Every ultrasound scanner made today starts with an Analog signal from the transducer (sometimes called the probe).  The transducer is like a speaker and a microphone.  First it transmits a pulse, then it “listens” for the returning echoes.

• Almost every ultrasound scanner made since 1980 takes the analog signals from the transducer and converts these signals to digital pulses for storage in the memory or to be processed by the ultrasound scanner.

 • Almost every ultrasound scanner made today contains a built-in CPU microprocessor (or computer) to provide keyboard functions, image processing and data storage.  The Tendon Calculation function is an example of this internal computer analyzing the ultrasound image and providing a useful analysis of the data.

 • Since most ultrasound scanners have a built-in computer, it isn’t necessary to have an additional laptop or desktop computer to have Digital Ultrasound capabilities.

 • The term Digital Output simply means that the display (or viewing monitor) is a digital LCD (liquid crystal display) display verses the analog CRT (cathode ray tube) display.  Analog CRT displays differ from the digital LCD displays but both have their advantages and disadvantages.  (See comparison between LCD and CRT below.)

FREQUENTLY ASKED QUESTIONS ABOUT DIGITAL ULTRASOUND:

Q.  What does Digital Ultrasound mean for me in my practice?

A.  The real question to ask is; “What do I need my ultrasound scanner to do for me?”  Most practitioners want their ultrasound scanner to:

1. Be very durable and provide good ultrasound images
2. Allow images from the ultrasound scanner to be transferred to their computer for storage, inserting into existing software of for sending images via email
3. Stand up to the “harshest” of conditions
4. Be very easy to transport, setup and operate

Q.  Do I need a laptop computer to have Digital Ultrasound?

A.   No. Depending on what model of ultrasound scanner that you have, you don’t need a laptop computer to:

            1.  Make measurements

            2.  Generate reports

            3.  Digitally process images (As in Tendon Calculation analysis)

            4.  Store images and transfer them to your existing computer system

Q.  Which is easier to use, a dedicated ultrasound scanner or a laptop with a transducer and module connected to it?

A.  The ultrasound scanner is almost always easier to use.  The dedicated ultrasound scanner is designed and built with ultrasound scanning in mind.  It’s functions and controls (including keyboards and trackballs) are made to work as an ultrasound scanner and to survive the harsh veterinary environment. The laptop, on the other hand, was designed and built to be a computer.  It’s functions and controls have to be adapted in order to operate as an ultrasound scanner.  Dedicated ultrasound scanners tend to be easier to use since their controls were specifically designed to work as a scanner.

Q.  Is the dedicated ultrasound scanner more durable than the laptop?

A.  Ultrasound scanners have been used in the harsh environment of the veterinary market for over 20 years with an excellent track record for durability.  Both the laptop and the dedicated scanner would be equally durable as far as the probes are concerned, but imagine what could happen to any laptop when used in this harsh environment, day after day.

CRT DISPLAYS vs. LCD DISPLAYS

CRT (or analog) displays have better image quality because they have an infinite number of “shades-of-gray”*. Also, the viewing angle of the CRT itself is also much wider than that of the LCD making them easier to see when not standing directly in front of the display.  However, the physical size of CRT displays (usually 6 to 9 inches deep) and their higher power consumption makes the CRT less desirable for hand held scanners. However, the better image quality of CRT displays makes them the monitor of choice for higher end scanners.

LCD displays (called Digital Output by some companies) are lighter and take up less space than CRT displays.  They also require less power, which makes them perfect for smaller hand held scanners.  The LCD has a limited number of shades-of-gray (usually 256) which gives it more of a  “pixelly image” than the CRT Monitor.

* Shades-of-gray - This is a term used in the imaging industry to describe how many shades or steps it takes to get from black to white.