INFLUENCE OF WHITE MATTER LESION FILLING ON VOLUMETRIC ASSESSMENT IN MULTIPLE SCLEROSIS

Abstract

Background: The continuous progress of information technology has made possible the creation of tools for post processing of magnetic resonance and other imaging modalities, including software programmes aimed at volumetric studies of the brain. They have the potential to enrich visual data with precise numeric values but have to be used with caution because of their possible susceptibility to errors if scans with specific pathology are fed in. Objective: The purpose of the present study is to assess whether filling white matter lesions on magnetic resonance scans of multiple sclerosis patients would influence volumetric values. Methods: MS lesions were filled on T1 3D images of 49 patients by the lesion-filling algorithm of FSL, using previously created lesion masks. Volumes of brain grey and white matter, peripheral grey matter and ventricle CSF were calculated using SIENAX for the filled and non-filled series, which were then compared. Results: There were statistically significant differences for white matter volume before and after lesion filling (p<0.05). No other volumes were significantly different. Conclusion: Filling of white matter lesions may be time-consuming, but can improve the accuracy of SIENAX by reducing bias due to misidentification of tissue intensity. Sometimes though, improvement of specific values may not reach statistical significance.

Keywords

• lesion filling
• multiple sclerosis
• SIENAX
• volumetric study