An Air Georgian Canadair CRJ-100, registration C-FWJI performing flight ZX-7380 from Saint Louis,MO (USA) to Toronto,ON (Canada) with 34 people on board, was enroute at FL250 near Fort Wayne,IN (USA) when the aircraft experienced problems with the cabin pressure prompting the crew to initiate an emergency descent, the passenger oxygen masks were released. The crew initiated a diversion to Detroit,MI (USA), subsequently determined that they had sufficient fuel to continue to Toronto at 10,000 feet and continued to Toronto for a safe landing about 75 minutes after leaving FL250. The Canadian TSB reported maintenance discovered a ruptured duct and replaced it. Subsequent pressurization tests found no further anomaly.