Enhancement of venous vasculature in susceptibility weighted images of the brain using multi-scale vessel enhancement filtering

To enhance the visibility of veins of the brain in susceptibility weighted imaging (SWI)-based MR venography using a 3D multi-scale vessel enhancement filter. The magnitude data of SWI were convolved with the second-order derivatives of the Gaussian function. Eigenvalue analysis of the Hessian matrix of the convolved magnitude images was used to enhance the veins. Multi-scale integration was formulated by the combination of maximum value among the normalized filter responses at multiple scales. The resultant 3D multi-scale MR venography demonstrated substantially enhanced visibility of the veins in SWI of the brain. Unlike the conventional SWI, the proposed technique does not suffer from the off-resonance artifact in the brain regions with severe field inhomogeneity and the signal loss in peripheral region of the brain in minimum-intensity projection. Both the background tissue in the brain and the noise in air were well suppressed in the filtered MR venography. Three-dimensional multi-scale vessel enhancement filtering based on the eigenvalue analysis of the Hessian matrix can effectively enhance the visibility of veins in susceptibility weighted images of the brain.