Comparison of Two Methods of Digital Images Analysis in Determining Growth of Acoustic Neuroma Tumors
Alexander, Brian Michael
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Acoustic neuroma tumors are slow growing benign tumors that arise in the inner auditory canal. Due to the slow growth, precise volume measurement and the resulting determination of growth rate are essential in developing a clinical course of action. Two methods of volume determination for acoustic neuroma tumors were investigated for precision. These methods differed from each other in the way they constructed three-dimensional models of the tumor from magnetic resonance images. Patients with acoustic neuroma tumors were scanned using magnetic resonance imagery to produce a series of images of the tumor. Images of the tumor are segmented from the normal tissue using one of two means; thresholding or eigenimage filtering. Segmentation produces enhanced contrast between lesion and normal tissue. Both of these methods are three-dimensionally based and differ from traditional methods in that traditional methods use a one or two-dimensional model of film measurement and extrapolation to three dimensions using mathematical formulas. Segmentation of a lesion from normal tissue is the most crucial issue for precise and accurate tumor volume determination using magnetic resonance imagery (Peck 1996). Acoustic neuromas are particularly appropriate for the comparison due to the aforementioned benefits of a precise system of measurement in a clinical setting, the relatively common incidence, strong enhancement with gadolinium injection, and encapsulation. The encapsulation of the tumor and globular shape help ensure that the tumor gadolinium volume corresponds closely to tumor margins. Both methods offered more precision than traditional models and are therefore improvements in assessing growth of acoustic neuroma tumors.