We scanned 19 patients ( mean age 53 ; 16 women ) with 20 saccular aneurysms treated with coils only , at 1.5 and 3.0 Tesla according to standard clinical 3D TOF-MRA protocols containing a shorter echo-time but weaker read-out gradient at 3.0 Tesla in addition to intra-arterial digital subtraction angiography ( IA-DSA ) .