The Federal Trade Commission has approved an agreement in which Carilion Clinic will sell two outpatient centers to resolve the government's concerns that it was stifling competition.

The settlement, which was reached in October, was approved 4-0 by the FTC on Tuesday, following a public comment period.

Earlier this year, the FTC challenged Carilion's purchase of the Center for Advanced Imaging and the Center for Surgical Excellence -- claiming that the health care giant engaged in anti-competitive behavior by absorbing the two independent operations that had offered low-cost alternatives to its own services.

Under the terms of the settlement, Carilion will divest the two centers and their related assets within three months to a buyer or buyers approved by the FTC.

"We're pleased that the FTC granted final approval of the proposed consent order," Carilion spokesman Eric Earnhart said.

Earnhart declined to comment in detail on the coming sale of the two centers. "All I can say at this point is we are moving forward and it is our intent to abide by the terms of the settlement," he said.

Had Carilion maintained control of the two clinics, it would have faced competition in the area from just one other provider, HCA Virginia Health System. That would have created a near-monopoly, the FTC contended, and could have led to an 800 percent increase in the out-of-pocket expenses for some procedures.

The Center for Advanced Imaging offers services such as MRIs and CT scans; the Center for Surgical Excellence provides gastroenterology and invasive pain management treatment and outpatient surgery.

Both clinics had been independently operated by Odyssey Imaging LLC and were marketed as low-cost alternatives to Carilion before they were bought by the Roanoke-based health care system.