Diagnostic ultrasound withstands test of time

Ultrasound has long been a prime target in imaging turf wars because it does not employ ionizing radiation. Radiology lost cardiac ultrasound, and it is questionable that the specialty will continue to be a major player in obstetrics.

Radiologists have complained for years of losing ground in vascular imaging as well. But in my long experience with vascular ultrasound, I have probably heard as many nonradiology vascular practitioners complain that it is radiologists who invade their turf and take away business that is rightfully theirs. The vascular pendulum swings both ways. Surgeons and radiologists should be aware, however, that cardiologists have made the greatest inroads in noninvasive vascular imaging in recent times.

Although radiologists believe that imaging should be under their purview, many facilities run by nonradiologists obviously practice excellent ultrasound imaging. And, of course, competing with clinicians who can self-refer is complicated. The availability of ever cheaper ultrasound scanners, which often produce excellent images, further confounds turf issues. Cost no longer hinders office installation. Luckily, some states tie reimbursement to accreditation, which may provide a measure of protection for radiologists. Office ultrasound practitioners will at least have to adhere to defined standards of quality and training.

Several drawbacks to ultrasound cannot be ignored. The requirement that it be performed by either a physician or ultrasound technologist has been a hindrance since the inception of the technique. Varying levels of talent and training lead to considerable inconsistency. In the U.S., we are at the mercy of the ultrasound technologist workforce, which always seems to be of limited availability. Certification for technologists, however, has been established for many years and has set at least a reasonable standard of experience and knowledge for those who have successfully obtained it. No one should employ a technologist who has not obtained the appropriate credential.

On a positive note, technologists' overall ability has improved substantially over the years as both the technique and those performing the scans have matured. Unfortunately, the aging of the technologist population brings with it numerous occupational injuries, which is becoming an increasingly recognized problem.

Speaking as a sonologist turned department chair, perhaps one of the greatest drawbacks of ultrasound that I face at this point is the lack of financial compensation. The professional billing component for ultrasound is dismal compared with MR or CT. Payers fail to recognize the importance of physician involvement in ultrasound, and payment has no relation to the amount of physician time dedicated to this technique. The unfortunate result is minimal physician involvement in most radiology facilities. This has placed us on a level similar to our nonradiologist colleagues, who simply come in at the end of the day and sign off the "preliminary" reports generated by the technologist. Along those lines, residents' hands-on involvement with ultrasound is decreasing in most institutions to the point that the majority of practicing radiologists will be incapable of performing a basic scan in the near future.

While I have practiced ultrasound for many years, I believe in a realistic approach to its place in imaging compared with other techniques. I can hardly justify a duplex ultrasound of the kidneys for renal artery stenosis when numerous studies show the superiority of CT angiography or MR, not to mention the better reimbursement. On the other hand, considering ultrasound a definitive test and questioning the need for a CT or MR frequently enables laboratories to maintain volume in many areas. Knowing when to obtain an ultrasound and passing that knowledge on to referring clinicians can help maintain the modality as a viable and important imaging technique.

While we continue to hear of radiology laboratories losing studies to nonradiologists, most facilities are seeing increasing volume. This suggests that although referral patterns may change, the use of ultrasound continues to grow.

Ultrasound is a relatively mature technology. The technical breakthroughs of '80s and '90s with color and endovaginal scanning have slowed, but improvements continue. All high-end modern ultrasound scanners provide spectacular images, and even low-cost units can be impressive. Three-D or contrast ultrasound may provide new avenues for studies in selected areas, but radiologists must institute such techniques and make their benefits known to referring doctors.

The use of ultrasound contrast agents is hindered in the U.S. by lack of specific FDA approval for radiologic indications. In areas where we find it useful, however, such as liver tumor or liver transplant imaging, we do not hesitate to employ contrast after a brief explanation of the "off-label use" to the patient. The cost of the agent can be recouped if proper documentation is provided to payers.

Ultrasound continues to play an essential role in radiology, and it is my belief that it will continue to do so. Given the maturity of the technology and its acceptance into routine imaging, it is not surprising that ultrasound no longer generates the excitement of modalities such as MR or PET. Even CT will likely plateau soon.

The landscape of radiology is one of constant change, and each new technology is refined, tested, and either incorporated into practice or eventually discarded. Ultrasound has withstood both the test of time and the onslaught of nonradiologists wishing to call it their own. As long as we continue to provide the best service and educate both radiologists and referring physicians, ultrasound will remain an important part of our practice.

Dr. Grant is chair of radiology at the University of Southern California's Keck School of Medicine in Los Angeles.