A new study published Tuesday in RSNA’s flagship journal offers key clues as to where radiology practices should target expansion plans.

Nearly 2,800 United States ZIP codes meet the criteria for being labeled as “extremely disadvantaged,” based on measurements including income, education and housing quality. Individuals living in these geographies were discovered to be less likely to have access to accredited imaging facilities, experts detailed in Radiology [1].

The disparity spanned across all major modalities and is likely to lead to delays in care, missed diagnoses and increased risk of death for these vulnerable populations.

“Prior studies have suggested that extremely deprived ZIP codes drive inequitable health outcomes,” corresponding author Anand Narayan, MD, PhD, vice chair of equity and associate professor in the Department of Radiology at the University of Wisconsin-Madison, and colleagues wrote March 14. “Prioritizing expansion of imaging facilities in areas with extreme deprivation may be required to reduce disparities in conjunction with comprehensive efforts to address social determinants of health.”

To reach their conclusions, researchers utilized the Area Deprivation Index, updated and maintained by scientists at UW–Madison’s school of medicine. Originally launched in the 1980s by the federal government, the index incorporates 17 different U.S. Census metrics to determine a community’s socioeconomic status. ZIP codes falling in the 97th percentile of the Area Deprivation Index were labeled as “extremely disadvantaged,” the authors noted. Conversely, those in the 3rd percentile were deemed “extremely advantaged,” while those falling outside of the two ranges were excluded from the analysis.

Nearly 7% of all 42,000 U.S. ZIP codes met the criteria for being extremely disadvantaged compared to about 2.5% being classified as extremely advantaged (1,028 total). The underprivileged areas were almost evenly split between rural (1,160) and urban (1,636), and advantaged geographies skewed more toward the city side (989) than country (39 rural).

Narayan et al. found that advantaged areas had greater access to American College of Radiology-accredited imaging facilities than disadvantaged ones. This included centers providing CT (32% had access in extremely advantaged areas vs. 21% in disadvantaged), MRI (32% vs. 19%), nuclear medicine (18% vs. 11%), PET (13% vs. 7%), ultrasound (29% vs. 14%—the largest gap found in the study), and lung cancer screening centers of excellence (12% vs. 5%). Higher proportions of the disadvantaged ZIP codes were located in the rural, southern parts of the United States, the authors noted.

The study serves as another reminder that the specialty needs to reach such isolated areas to further address disparities.

“If we as a community want to improve overall access to recommended imaging services, it is critical that we incorporate rural perspectives, particularly as many academic radiology departments are centered in urban or suburban areas,” Narayan said in a statement from the Radiological Society of North America.

“Radiology department leaders can use the [Area Deprivation Index] to inform the expansion and allocation of imaging services to ensure that areas of extreme deprivation have access to high-quality imaging services,” he added later.