via the Situation Room Blog at NHL.com,

At 12:32 of the first period in the Blackhawks/Bruins game, video review was initiated by the NHL Situation Room because the puck entered the Boston net. The referee had blown the play dead prior to Chicago Blackhawks forward Marian Hossa pushing the goaltender's pads and the puck across the goal line. No goal Chicago.

Watch the CBC version of the play and below, the NBCSN broadcast...