Room: Exhibit Hall
Purpose: Stereotactic radiosurgery (SRS) has been established as an effective method to treat AVM. Clinically, 3D volume projection to 2D plane is gold standard in visualizing the nidus, such as orthogonal DSA (digital subtraction angiography). However, DSA is often not applicable to all SRS systems. As a result, CTA/MRA images are commonly used as alternative. But axial images of CTA/MRA are not optimal for accurate delineation of AVM nidus. Herein, a novel technique is presented that allows more accurate contours of the AVM nidus based on MIP (maximum intensity projection) from CTA/MRA.
Methods: We developed a novel approach that is based on 3D-to-2D projection and back-projection to recreate nidus contour on 2D axial images. The method makes use of MIP from CTA/ MRA images. The AVM nidus are first delineated on the MIPs from multiple projection angels. The delineated regions are then back-projected to the â€œk-spaceâ€? to reconstruct AVM nidus that is the intersected region of multiple back-projections.
Results: The developed method was tested on a digital phantom with an artificial AVM nidus served as the â€œground truthâ€?. The results show that the deviation between the â€œAVMâ€? volumes reconstructed from MIPs and â€œground truthâ€? reaches as low as 8.27% when 15 projections were used. The method was also applied to a real AVM patient MRA data set. Compared to that of direct delineation from axial images, the reconstructed AVM contours were more appreciated(Fig.2).
Conclusion: A novel technique was developed to use MIPs from MRA/CTA to reconstruct contours of AVM nidus on axial images that can be used for stereotactic radiosurgery of AVM. A software was accordingly developed to test the methodology on both a digital phantom and a MRA set. The results showed both technical feasibility and clinical applicability.