Braided medical devices

An implantable vaso-occlusive device for occluding an aneurysm, comprising:

• a braided member formed out of a first plurality of filaments interwoven with a second plurality of filaments, the braided member formed into a flattened tubular braid, the flattened tubular braid having a constrained configuration when constrained in a lumen of a delivery catheter and biased into a self-expanded deployed configuration when not constrained;
• wherein filaments of the first plurality are helically wound in a first rotational direction along an elongate axis of the braided member, and filaments of the second plurality are wound in a second rotational direction opposite the first rotational direction along the elongate axis of the braided member, such that filaments of the first plurality cross over and under filaments of the second plurality at each of a plurality of cross-over locations axially spaced along the elongate axis of the braided member, and
• wherein the braided members form a plurality of different sections in which the different sections each have a different density of braid members, including a first section and a second section in which the first section has a less dense arrangement of the braid members than the second section.