Spotlight on Technology and Technique
Ultrasound Times Four
Combining multiple instruments into a single unit saves time, space -- and money.
BY CHRISTOPHER KENT, SENIOR ASSOCIATE EDITOR

New technology often heralds greater ability to diagnose and treat patients. It may also mean more instruments in your practice, which can be expensive and space-consuming. Similarly, adding specialists to your practice may expand the number of instruments you need to have in your clinic.

The P-45 UBM Plus ultrasound workstation from Paradigm Medical, which received FDA approval at the end of 2000, has been designed to address that issue. The P-45 combines multiple ultrasound technologies in one instrument, at a price only a little higher than one of the instruments purchased alone.

According to Paradigm, the idea behind the P-45 workstation was to take Paradigm's popular ultrasonic biomicroscope (UBM) technology and combine it with A scan and B scan technology. Ultimately, a variation of the A scan, which the company calls "diagnostic A," was included. The result is a comprehensive workstation that can provide high-resolution information about all parts of the eye, including structures in the anterior segment that relate to glaucoma.

Putting it all together

The P-45 UBM Plus integrates these four ultrasound tools:

• A scan, for calculating axial length and IOL power. Once the workstation has taken this measurement and you add the pertinent information provided by the lens manufacturer, the P-45 can calculate the appropriate IOL power for you, using whichever formula you prefer.

• B scan, for imaging the entire globe. The P-45's B scan is able to image both the anterior and posterior segments. It can be used to detect tumors, aberrations in retinal adherence, detachments, cysts, foreign bodies and displaced IOLs.
  In B-scan mode you can display up to four images onscreen simultaneously, one of which can be the current real-time image. In addition, because the B-scan image is a translation of information compiled from a series of 500 A scans taken along multiple vectors, you can select any particular vector from the image and see an A-scan graph of that vector. (This allows an even more precise analysis of distances.)
  B-scan mode also allows you to use onscreen "calipers" to measure distances (useful for monitoring changes in tissue) by simply clicking on points in the image.

• UBM (ultrasonic biomicroscope). While the A- and B- scans use an ultrasound frequency of 10 MHz, the UBM uses a frequency of 50 MHz. The higher frequency generates much higher resolution. (The P-45 -- like its predecessor, the P-40 -- can distinguish points as close together as 50 microns.) The trade off is that the ultrasound doesn't penetrate as far into the eye.
  As a result, this mode allows you to visualize the front 5 to 7 mm of the anterior chamber with exceptionally high resolution, displaying structures such as the cornea, iris, trabecular meshwork, and ciliary body and sulcus in detail. According to Paradigm, the P-45 UBM is the only one available with this level of resolution.
  This technology was originally developed to image anterior segment tumors, but was quickly adopted for assessment of glaucoma and other disorders. It's helpful for finding and monitoring cysts that can't be seen directly, detecting improperly located intraocular lens haptics, or for use following iridectomy or trabeculectomy to determine whether the channel has remained open.
  As with B-scan images, you can select a particular sampling line and see an A-scan analysis of distances along that line, and you can measure distances or angles using the onscreen "calipers."

• "Diagnostic A." This technology uses an ultrasound frequency close to that used in an A scan, but special signal processing allows it to provide information about tissue density and elasticity throughout the eye. The resulting graph makes it easy to detect tissue with unusual characteristics, such as tumors or swelling, even behind the globe. (This feature was optional in Paradigm's previous A- and B-scan units; it's standard in the P-45 UBM Plus.)

Other features and benefits

Besides the convenience of having four technologies available in a single instrument, the P-45 UBM Plus offers 

other practical design features:

• Real-time image. B scan and UBM images are "live," onscreen. Any frame can be saved by clicking on a footpedal. The image also shows numerical data, system settings and a time stamp, all captured when you save the image.

• Pre- and post-processing capabilities. The P-45 allows adjustable time/gain signal control and a variety of processing functions to bring out different aspects of a scanned image (by enhancing contrast, for example).

• User-friendly controls. These include:

  • two foot pedals, one for starting/stopping scans, one for saving an image to disk

  • three-button trackball and thumbwheel control for manipulating the onscreen cursor

  • articulated arms to make it easy to position and move the probes during exams

  • lightpen entry of patient information.

• High-capacity hard drive. The P-45 can store about 3,000 images for future reference. Information and images can be transferred to an external drive or Zip Disk for archiving or transporting to another location.

Feedback from the field

Hiroshi Ishikawa, M.D., of Glaucoma Associates of New York, has worked with the P-45 UBM Plus for almost a year. "The beauty of this instrument is integration. It's very convenient to have all these capabilities in one machine. If you want to see something interesting in the front of the eye, use the UBM. For the back of the eye, use B-scan mode. With the two technologies you can cover the entire eye.

"Sometimes we need to move the instrument into the OR, and having everything in one unit saves a lot of time and effort."

Roger Harrie, M.D., who practices in Salt Lake City, uses the P-45's UBM function almost exclusively. "This technology is very valuable for anterior segment work, such as monitoring the cornea, iris, or tumors -- it has excellent resolution. In fact, for certain conditions this technology is essential. Some anterior segment problems simply can't be seen any other way."

Working toward the future

Paradigm is working on enhancing its ultrasound technology for future models, making it possible to upgrade the P-45 to even higher resolution and greater information processing capacity. The company also hopes to offer 3-D imaging as a potential upgrade within the next few years.

For more information about the P-45 UBM Plus, contact Paradigm Medical at (801) 977-8970, or visit the Web site at www.paradigm-medical.com.

Are you aware of new products or technology that have made (or are likely to make) a significant difference in practice? Contact Christopher Kent at kentcx@boucher1.com to find out about possible coverage in a future issue.