Intravascular devices

1. An implantable medical device, comprising:

an elongate member having a cross-sectional dimension that is less than 0.00085 inch,

wherein the elongate member is made from a material comprising a platinum-tungsten alloy having 16%-25% tungsten by weight.

2. The implantable medical device of claim 1 ,

wherein the implantable medical device has a longitudinal axis and a length measured in a direction of the longitudinal axis that is at least 1.2 inch,

wherein the implantable medical device is insertable lengthwise into an inner lumen of a tube having an inner lumen diameter not greater than 0.02 inch, and

wherein the implantable medical device has a column strength sufficient to allow the implantable medical device to be pushed through the lumen without undergoing buckling, kinking, or plastic deformation.

3. The implantable medical device of claim 1 , wherein the elongate member has a greater ultimate tensile strength, a greater Young's modulus, and a lesser magnetic susceptibility, respectively, than those of an identically dimensioned alternative elongate member composed of an alternative platinum-tungsten alloy having a percentage of tungsten that is not greater than 8% by weight.

4. The implantable medical device of claim 1 , wherein the cross-sectional dimension of the elongate member is in a range between 0.0001 inch to 0.0008 inch.

5. The implantable medical device of claim 1 , wherein the material has a Young' modulus of 30 Msi or higher.

6. The implantable medical device of claim 1 , wherein the elongate member has an ultimate tensile strength (UTS) that is 350 ksi or higher.

7. The implantable medical device of claim 1 , wherein the elongate member forms a part of a braid.

8. The implantable medical device of claim 1 , wherein the material further comprises one or more of Ta, Ir, Re, Rh, Ru, Mo, Zr, Hf and Au.