Detection of tubular structures in 3D images is an important issue for vascular medical imaging. We present in this report an extension of a previous work done by the same authors [KMA98]. The following improvements have been done: a better state of the art, a modification of the response function by introducing a coefficient theta whose value is deduced from the model, an experimental study on synthetic images with junctions, tangent structures, structures with varying diameters, and tubular structures with Gaussian-like cross-sections or ``convolved bar-like'' cross-sections, an experimental study on a phantom image and on real X-ray and MRA images.