Most lower-extremity MRI exams are still interpreted by radiologists, but those that are read by nonradiologists are more likely to have been performed during the week and to be less complex cases, according to a study published online July 31 in the American Journal of Roentgenology.
A review of Medicare claims from 2012 to 2014 revealed that nonradiologists -- primarily orthopedic surgeons -- interpreted approximately 20% of lower-extremity MRI exams. However, the percentage of lower-extremity MRI studies being interpreted by radiologists increased significantly if the scans were performed on weekends, originated in the emergency room (ER), came from inpatients, or involved more complex cases.
"Compared with nonradiologists, radiologists disproportionately provide services on weekends, on patients in the highest acuity locations, and on the most clinically complex patients," wrote the study authors, led by Dr. Paige Sharp from the Emory University School of Medicine.
According to a November 2017 AJR study by Gyftopoulos et al, radiologists were the most common specialists to bill for musculoskeletal extremity imaging between 1994 and 2013, accounting for 84% of MRI reads. With extremity MRI scans escalating by more than 600% over a 20-year period, orthopedic surgeons have become the second-most common specialist to bill for musculoskeletal imaging interpretations.
"Anecdotally, some radiologists complain that more complex cases are referred to radiologists, while less-demanding, straightforward cases are kept by competing specialists to interpret themselves," Sharp and colleagues wrote. "However, we are unaware of data to support these claims."
To help settle the issue, the researchers retrospectively collected Medicare fee-for-service claims data on patient demographics, the provider and specialty, date, and location of the lower-extremity MRI scan. They tallied a total of 125,800 lower-extremity MRI scans: Radiologists read 92,203 (73%) of these exams, while nonradiologists read 17,745 (14%) of the studies. Sharp and colleagues could not accurately identify the specialists who handled the other 15,852 (13%) exams.
Based on the 109,948 lower-extremity MRI scans for which a reader could be confirmed, radiologists almost exclusively were given the responsibility of interpretations from the ER and inpatient setting, according to the researchers. Subsequently, they were given the most complex cases and relied upon most heavily upon during weekends, when nonradiologists were likely off duty.
| Interpreting physician for lower-extremity MRI studies | ||
| Nonradiologists | Radiologists | |
| Weekdays | 17,260 (16%) | 85,991 (83%) |
| Weekends | 485 (7%) | 6,212 (93%) |
| Inpatient/ER settings | 51 (1%) | 6,499 (99%) |
| Most clinically complex cases | 461 (10%) | 4,228 (90%) |
The decrease in the proportion of MRI exams read by nonradiologists from weekdays to weekends was statistically significant (p < 0.0001).
"Not only do radiologists disproportionately provide services during less opportune days of the week (i.e., weekends), but those services are also disproportionately rendered to patients in the highest acuity settings," the authors concluded. "To promote patient access and minimize disparities, future pay-for-performance metrics should consider temporal, acuity, and complexity parameters."
