Hilal et al., but these were short, stiff coils that offered no control, preventing dense packing of the aneurysm. Controllable microguidewire systems were later used. Detachable coil system In 1983 the use of electrically induced thrombosis for intracranial aneurysms was described for the first time. A stainless steel electrode supplied a positive current to the aneurysm to stimulate electrothrombosis. Minimal occlusion was achieved, but the researchers discovered that the erosion of the electrode due to electrolysis would be useful as a detachment system. Detachable coils were constructed from a platinum coil soldered to a stainless steel delivery wire, first described in 1991 by Guglielmi et al. When combined with a controllable microguide wire system, multiple coils could be inserted to fully pack an aneurysm. Research Given the complexity of modeling the vasculature, much research has been devoted towards modeling the hemodynamics of an aneurysm before and after an intervention. Techniques such as particle image velocimetry (PIV) and computational fluid dynamics/finite element analysis (CFD/FEA) have yielded results that have influenced the direction of research, but no model to date has been able to account for all factors present. Advantages of the in-silico research method include flexibility of selecting variables, but one comparative study has found that simulations tend to over-emphasis results compared to PIV, and are more beneficial for trends than exact values. Medical images, particularly CT angiography, can be used to generate 3D reconstructions of patient specific anatomy. When combined with CFD/FEA, hemodynamics can be estimated in patient specific simulations, giving the clinician greater predictive tools for surgical planning and outcome evaluation to best promote thrombus formation. However, most computer models use many assumptions for simplicity, including rigid walls (non-elastic) for vasculature, substituting a porous medium in place of physical coil representations, and navier-stokes for fluid behavior. However, new predictive models are being developed as computational power increases, including algorithms for simulations of coil behavior in-vivo. References Interventional radiology Neurosurgery