On 3.0-Tesla MRA , remnants were larger than on 1.5-Tesla MRA ( difference : 0.7 mm ; 95 % CI : 0.3-1 .1 ) and larger than on IA-DSA ( difference : 1.0 mm ; 95 % CI : 0.6-1 .5 ) with similar agreement on occlusion levels with IA-DSA for both field strengths ( 0.53 ; 95 % CI : 0.23-0 .84 for 1.5-Tesla MRA and IA-DSA ; 0.47 ; 95 % CI : 0.19-0 .76 for 3.0-Tesla MRA and IA-DSA ) .