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An algorithm for stereotactic localization by computed tomography or magnetic resonance imaging.

J Dai·Y Zhu·H Qu·Y Hu
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Abstract

Stereotactic localization of an intracranial lesion by computed tomography or magnetic resonance imaging requires the use of a head frame that is fixed to the skull of the patient. To such head frames are attached either N-shaped or V-shaped localization rods. Because of patient positioning, the transverse imaging slices may not be parallel to the frame base; a coordinate transformation algorithm that takes this possibility into consideration is crucial. Here we propose such an algorithm for a head frame with V-shaped localization rods. Our algorithm determines the transformation matrix between the image coordinate system of a transverse image and the frame coordinate system. The determining procedure has three steps: (a) calculation of the oblique angles of a transverse image relative to the head frame and calculation of the image magnification factor; (b) determination of the coordinates of four central markers in both coordinate systems; and (c) determination of the 3 x 3 transformation matrix by using the coordinates of the four markers. This algorithm is robust in principle and is useful for improving the accuracy of localization.

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AlgorithmsHumansMagnetic Resonance ImagingModels, TheoreticalTime FactorsTomography, X-Ray ComputedJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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J Dai, Y Zhu, H Qu, Y Hu. 2001. An algorithm for stereotactic localization by computed tomography or magnetic resonance imaging.. https://doi.org/10.1088/0031-9155%2F46%2F1%2F401

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