A magnetic resonance imaging magnet assembly is provided. The assembly comprises a outer thermal shield having an operational temperature. The assembly further includes a cold sleeve assembly comprising a plurality of braid elements mounted to a cooler block and a highly thermally conductive block mounted between the cooler block and the outer thermal shield. The highly thermally conductive block is welded to the outer thermal shield and is welded to the cooler block. The highly thermally conductive block has greater thermal conductance than the outer thermal shield.