No significant differences in CNR IM/LVC were noted for HD acquired 5 min after CM administration compared to SD acquired at 10 ( p = 0.34 ) , 15 ( p = 0.96 ) and 20 ( p = 0.41 ) min , and between HD at 10 min compared to SD acquired at 15 min ( p = 0.78 ) and 20 min ( p = 0.32 ) .