Diagnostic flexibility of B-scan makes it a sound investment

November 1, 2011

B-scan ultrasound is very useful technology for imaging and diagnosing posterior segment pathology.

Key Points

Dr. Cymbor said he became proficient in performing and interpreting B-scans during his VA hospital-based residency in 1997. Impressed by its overall usefulness and surprised at the number of diagnoses it made easier, he discussed a purchase with his colleagues at Nittany Eye Associates, Nittany, PA, when he joined the practice in 1998. However, cost was a deterrent, said Dr. Cymbor, vice-president, Nittany Eye Associates.

"Now, it is easier for practices to justify a B-scan purchase from an economic perspective. Even though the imaging can't be delegated to a technician, we have found it can be done quickly and efficiently through prior planning so that we and our patients can benefit from the information it provides," he said.

The B-scan unit purchased by Dr. Cymbor and colleagues in 2010 cost $6,000 for the head, which is connected to a dedicated laptop computer that can be moved from room to room. Because it is often possible to predict what patients may need to be examined with B-scan, based on their primary complaint when they call for an appointment, the technician can have the unit set up and ready to use when the patient enters the exam room.

Considering that a conventional B-scan procedure in Pennsylvania is reimbursed at $88.45 per eye and the cost of the B-scan head is $6,000, the purchase price would be paid off if the instrument were used for 1.2 visits per week, Dr. Cymbor said.

"Our method for analyzing whether an equipment purchase makes fiscal sense is to calculate how many uses would be needed to recoup the cost. If we can pay it off in the first year, we consider it worthwhile," he explained.

"Posterior vitreous detachment (PVD) is the pathology we image most, and we know we are seeing more than 1.2 PVD cases alone per week. So, it made economic sense to purchase this instrument, and it has done well for us from a reimbursement perspective," he added.

Although PVD can be identified via conventional fundus exam, an advantage of using B-scan is that it gives a better sense of whether the PVD is complete or incomplete, which is important for prognostication, Dr. Cymbor said. The procedure is done using a coupling gel (ocular lubricant gel) and with the eye closed for the patient's comfort.

Clinical applications

Other vitreous pathologies for which B-scan-ning is useful include asteroid hyalosis, vitreous and subvitreal hemorrhage, and posterior hyphema. B-scan is also valuable for detecting various peripheral retinal pathologies, including tears, retinal and retinal pigment epithelium (RPE) detachments, and retinoschisis.

B-scan can be used for identifying macular pathology, but it has been largely replaced by optical coherence tomography (OCT). Similarly, it can also be used to diagnose optic nerve head edema, but there are better technologies for that application as well. B-scan, however, remains important for optic nerve head imaging, where it is used most commonly to study optic nerve head drusen.

"B-scan is particularly helpful for identifying buried optic nerve head drusen that can otherwise be difficult to diagnose," Dr. Cymbor said.

B-scan is also performed in trauma cases and to look for foreign bodies, although care must be taken in these situations because it is a contact instrument. In addition, it is helpful for diagnosing tumors, especially those located in the periphery, which many are.

"One can use amplitude readings advantageously when scanning tumors to differentiate different types of ocular tumors and to discriminate between ocular tumors and metastatic lesions arising from an extraoc-ular primary tumor," he said.

Dr. Cymbor recommended the Web site http://www.ophthalmicedge.org/ which features a comprehensive B-scan video library.

FYI

Michael J. Cymbor, ODE-mail: mcymbor@nittanyeye.com

Dr. Cymbor has no financial interest in the subject.