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Benjamin A. King, Carlos Parra, Matthew W. Wilson, Ibrahim Qaddoumi, Robert Ogg; Tumor Localization on the Retinotopic Map: An MRI-based Approach to Correlating Retinoblastoma with its Impact on Visual Cortex. Invest. Ophthalmol. Vis. Sci. 2011;52(14):2486.
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© ARVO (1962-2015); The Authors (2016-present)
To quantify retinoblastoma location on the retinal surface inorder to to correlate the lesion with the areas of retinotopicallyorganized cortex to which it projects.
Using Syngo Viewer software (Siemens AG, Germany) MR imagesof the eye in 91 consecutive retinoblastoma patients (33 bilateral)were evaluated. For each MRI the central visual axis was approximatedrelative to the optic nerve. A series of points along each tumormargin were evaluated for their polar angle and angle of eccentricityrelative to the central visual axis (Fig. 1). The tumor outlinewas then interpolated on a polar coordinate system with thefovea as the central reference point (Fig. 2). Retinal photographywas used to ensure that the tumor graph was consistent withthe actual lesion.
Tumors in 77 of 124 eyes were successfully delineated on ourretinal surface map. In the remaining 47 eyes, 43 had tumorswhich blocked all areas within the central 60° of visionhence the remaining functional retina was not significant enoughto quantify. Tumors in 4 eyes were complicated by hemorrhageor vitreous seeding and were thus too complicated to analyze.
Our technique proved to be an efficient and reliable approachto quantifying the location of tumors with respect to the visualfield of each retina. Such an approach will be most beneficialin guiding fMRI studies of visual cortex in patients in whomretinal function is compromised.
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