The present invention relates to a method and apparatus for pretreatment planning endovascular coil placement, comprising steps of: a) analyzing three-dimensional data enabling visualization of a volume of interest containing at least a part of a blood vessel with an aneurysm; b) determining the centerline of the vessel; c) determining the aneurysm diameter; d) determining the aneurysm dome height; e) creating a three-dimensional surface model of the aneurysm in the vessel, using the results from the previous steps; f) estimating the volume expansion of one or more coils with the aid of said surface model; and g) visual simulating at least one according to the estimated virtual coil being to place inside the aneurysm.