Mark Vabulas

University of Texas MD Anderson Cancer Center, Houston, Texas, United States

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Publications (3)5.3 Total impact

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    ABSTRACT: Surgery for tumors in eloquent brain faces immense challenges when attempting to maximize resection and avoid neurological deficits. In order to give the surgeon real-time atlas-based anatomical information linked to the patient's anatomy, we developed a software-based interface between deformable anatomical templates (DAT) and an intra-operative navigation system. Magnetic resonance imaging (MRI), diffusion tensor imaging (DTI) and/or functional MRI (fMRI) were performed on 3 patients pre-operatively for the purposes of tumor resection using neuronavigation. The DAT was registered to the patients' navigation coordinate system and utilized coordinates from the navigation system during surgery. This provided the surgeon with a list of proximal anatomical and functional structures and a real-time image of the atlas at that location fused to the patients' MRI. The clinical feasibility of this approach was evaluated during resection of three eloquent tumors (right post-central gyrus, left inferior frontal gyrus, and left occipital cuneus gyrus). Tumor resection was performed successfully in all three patients. Using the coordinates from the navigation system, anatomical and functional structures and their distances were visualized interactively during tumor resection using the DAT. This is a proof of concept that an interactive atlas-based navigation can provide detailed anatomical and functional information that supplements MRI, DTI, and fMRI. The atlas-based navigation generated distances to important anatomic structures from the navigation probe tip. It can be used to guide direct electrical stimulation and highlight areas to avoid during tumor resection.
    Neurosurgery 10/2013; · 2.53 Impact Factor
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    ABSTRACT: This paper describes the methods used to create annotated deformable anatomic templates (DATs) and display them in a patient's axial 2-dimensional and reformatted volume brain images. A senior neuroradiologist annotated and manually segmented 1185 color-coded structures on axial magnetic resonance images of a normal template brain using domain knowledge from multiple medical specialties. Besides the visible structures, detailed pathways for vision, speech, cognition, and movement were charted. This was done by systematically joining visible anatomic anchor points and selecting the best fit based on comparisons with cadaver dissections and the constraints defined on the companion 2-dimensional images. The DAT is commercially available for use on a picture archiving and communication system or as a standalone workstation. The DAT can quickly embed extensive, clinically useful functional neuroanatomic knowledge into the patient's brain images. Besides labeling visible structures, DAT displays clinically important, previously uncharted subdivisions of the fiber tracts.
    Journal of computer assisted tomography 05/2012; 36(3):354-9. · 1.38 Impact Factor
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    ABSTRACT: This study evaluated the concordance between the Deformable Anatomic Template (DAT)-identified origin of motor hand fibers and localization of the motor cortex of the hand by functional magnetic resonance imaging (fMRI). Preoperative fMRI during hand motor tasks was performed on 36 hemispheres in 26 patients with gliomas in or near eloquent areas. Reformatted volume-rendered surface images were labeled with the DAT's hand motor fibers and fMRI data. Five reviewers assessed the data for concordance. Available fMRI data were diagnostically usable in 92% (33/36 analyzed hemispheres), with DAT anatomic accuracy in the remaining cases. The DAT prediction and fMRI findings were concordant in all 9 normal hemispheres and in 20 (83%) of 24 glioma-bearing hemispheres. The 4 discordant cases resulted from substantial mass effect by large frontal tumors. This study validated DAT's anatomic atlas and alignment process for the expected position of the motor cortex of the hand.
    Journal of computer assisted tomography 03/2012; 36(2):280-4. · 1.38 Impact Factor