Castlight Health issued its second annual U.S. Costliest Cities Analysis this week, using medical claims data to show the variety of prices patients are asked to pay for different medical procedures across the country.

According to the study, the price for a mammogram in the U.S. varied tremendously over the last year, costing anywhere from $43 (in Sarasota-Bradenton, Fla.) to $1,898 (in New York City) at individual centers. Meanwhile, the city with the highest average cost for a mammogram was Sacramento, Calif., clocking in at an average of $485 per exam.

The city with the widest range in prices for mammograms was Dallas-Fort Worth, Texas, where mammograms range anywhere from $50 to $1,045. The average price in Dallas was $211.

Kristin Torres Mowat, Castlight Health vice president of strategic alliances and data operations, called these numbers “eye-opening” in a statement, worrying that such variation could result in some patients not receiving treatment at all.

“It's especially disturbing that women and their employers could be needlessly overpaying for mammograms and other critical health services,” she said. “Despite mandated insurance coverage for certain services, evidence shows that women forgo basic preventative care due to cost considerations and that delaying preventative care can harm patient health and increase future medical spending.”

The Castlight Health study studied other imaging exams as well. CT scans of the head or brain, for instance, varied from $78 (in Washington, D.C.) to $4,214 (in Pensacola, Fla.). Besides having the lowest priced CT scan of the head or brain for an individual center, Washington, D.C. was also the least expensive city on average for the procedure.

The most expensive city to get a CT scan of the head or brain was Indianapolis, Ind., with an average of $1,362 per exam. Charlotte, N.C., came in at a close second with an average of $1,325.

The study also showed a wide range of final costs for an MRI of the lower back. Prices ranged from $212 (Utica-Rome, N.Y. ) to $5,546 (Pensacola, Fla.).

The most expensive cities to get a MRI of the lower back was, once again, Indianapolis, Ind., with an average price of $2,307.

Overall, the Castlight Health study shows that patients are dealing with a healthcare system where prices are inconsistent, even when staying within the same city. Giovanni Colella, MD, Castlight Health co-founder and CEO, said in a statement that she is hopeful employers will pay attention to these statistics.

"This study has data that is vital to understanding how broken the U.S. healthcare system really is, and we sincerely hope that employers and consumers take note," Colella said. “The only way that employees and their employers can even begin to manage healthcare spending is by understanding how much it costs.”