Healthcare insurance carriers, policymakers, and radiologists are concerned about self-referral and utilization by other specialists of advanced imaging techniques like MRI and CT. Our purpose was to determine to what degree neurologists compete with radiologists in MRI and CT of the central nervous system (CNS).

We searched the 1997 through 2002 Medicare Part B fee-for-service databases for all diagnostic CPT-4 codes relating to CT and MRI of the head and spine. They were then sorted by Medicare physician specialty codes to determine the number of studies performed by radiologists and neurologists. The 5-year trends were also ascertained.

In 2002, radiologists performed 4,322,277 cranial CTs and 1,719,268 cranial MRIs, which represented 39% and 94% increases respectively compared with 1997. Radiologists also performed 399,015 spine CTs and 1,318,811 spine MRIs, representing 19% and 83% increases respectively compared with 1997. By comparison, neurologists in 2002 performed 25,145 cranial CTs and 45,590 cranial MRIs, representing 25% and 43% increases respectively compared with 1997. Neurologists also performed 1101 spine CTs and 19,561 spine MRIs, representing a 33% decrease and a 41% increase respectively compared with 1997. In 2002, neurologists performed a total of 91,397 CTs and MRIs of the CNS compared with 7,759, 371 such studies performed by radiologists. Neurologists’ shares of the market in 2002 were as follows: cranial CT – 0.6%; cranial MRI – 2.4%; spine CT – 0.3%; spine MRI – 1.3%. These percent shares were all lower than they had been in 1997.

In the Medicare population in 2002, neurologists performed only 1% as many CNS CT and MRI examinations as radiologists. Furthermore, between 1997 and 2002, neurologists’ growth rates in MRI and CT of the head and spine were all lower than those for radiologists. Neurologists have very little market share in neuroimaging; that share appears to be declining. Their utilization of neuroimaging is growing more slowly than radiologists’ utilization. It would also seem that neurologists have very little opportunity to obtain formal training in advanced CNS imaging.

V.M.R.,D.C.L.,L.P.,J.S.,A.M.: no disclosures