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L. A. Mawn, L. Blackwell, R. Thompson, R. L. Galloway; Comparision of Fiducial Placement for Image Guided Orbital Surgery. Invest. Ophthalmol. Vis. Sci. 2010;51(13):18.
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© ARVO (1962-2015); The Authors (2016-present)
In a previous project we compared fiducial placement for image guided with traditional placement of fiducials to a mathematically optimized periorbital configuration and showed improved target registration error with the optimized fiducial placement. To translate this finding to surgical applications we compared the optimized fiducial placement to traditional placement in the commercially available Stealthstation/S7.
A replica of the human skull with was created. A mathematical algorithm, simulated annealing, was used to determine optimal fiducial placement. External skin fiducials were placed by both the traditional random method and based on the optimized placement. Preprocedural computed tomographic (CT) images of the phantom were loaded into a commercially available navigation system. The registration was then determined 20 times for both fiducial arrangements. The accuracy number that the Stealth Station/S7 rendered was then compared with both arrangements of fiducials. An accustar bone marker secured at the orbital apex was located with image guidance with both registration methods.
The traditional neurosurgery placement method rendered an accuracy number of 0.970 mm + 0.208 compared to the optimized position of 1.13 + 0.98 (p= 0.017). The CT scan position of the accustar position within the phantom was accurately determined with both arrangements of fiducials.
With a mathematically rigorous process of simulated annealing, we have previously shown that improved registration results for image guidance are achieved by optimizing fiducial placement. We urge caution when drawing conclusions from the accuracy numbers produced from the commercially available image guidance systems as they are not true target registration calculations.1. Atuegwu NC, Mawn L, Galloway R. Transorbital endoscopic image guidance.Conf Proc IEEE Eng Med Biol Soc. 4663-6, 2007.2. Ateugwu NC, Galloway R. Volumetric characterization of the Aurora magnetic tracker system for image-guided transorbital procedures. Phys Med Biol 53(16):4355-68, 2008;
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