An exhaust gas treatment system for reducing emissions from an engine includes an exhaust conduit adapted to supply an exhaust stream from the engine to an exhaust treatment device. The conduit includes an aperture. An injector injects a reagent through the aperture and into the exhaust stream. A flow modifier is positioned within the exhaust conduit upstream of the injector. The flow modifier increases the velocity of the exhaust gas at a predetermined location within the conduit relative to the injected reagent.