Westwood imaging firm RadNet Inc. has acquired Diagnostic Imaging Group for about $56.7 million and 1.5 million shares of RadNet stock.

The deal should give RadNet about $70 million in extra revenue annually. The news sent RadNet shares down 1.7 percent Friday on the Nasdaq stock exchange, closing the trading day at $5.72.

Diagnostic Imaging Group, headquartered in Hicksville, NY, owns and operates 17 imaging centers in the New York City area. It employs more than 600 people.

Last year, Diagnostic Imaging Group agreed to pay the U.S. government, New York and New Jersey a total of $15.5 million to resolve allegations that it falsely billed federal and state health care programs for tests that were not performed or not medically necessary, as well as claims that it paid kickbacks to physicians. The firm admitted no liability.

RadNet extensively reviewed the settlement that Diagnostic Imaging Group made with the Office of Inspector General as well as the New York firm’s business practices, explained RadNet Chief Financial Officer Mark Stolper in an email.

“We were able to satisfy ourselves that the business practices in question were terminated prior to our acquisition,” Stolper wrote. He added that the Office of Inspector General reviewed RadNet’s compliance program and determined the firm will not be subject to a corporate integrity agreement Diagnostic Imaging Group agreed to as part of the settlement.

RadNet has been building its network of New York and New Jersey locations over the past year. Including these newly acquired centers, the firm now operates 74 locations in the greater New York Metropolitan area.

“With over 20 million residents, the greater New York metropolitan area is an enormous marketplace for us,” said RadNet Chief Executive Dr. Howard Berger. “I believe there are substantial additional growth opportunities on which we can capitalize.”