A federal judge has rejected Aetna Inc.'s bid to dismiss a class-action lawsuit over its insurance coverage, Reuters reported.

The lawsuit claims that Aetna improperly denied insurance coverage for a type of treatment for depression that sends electromagnetic pulses into the brain, according to the report. U.S. District Judge Janet Hall in New Haven, Conn., said the lawsuit merits a trial as it raised several questions over whether the health insurer denied coverage for the treatment based on an arbitrary interpretation of its members' plans.