Bestimmung der zerebralen Atrophie bei neurologischen Erkrankungen des Marklagers mittels SIENA

Measurement of brain atrophy in neurological white matter diseases using the SIENA method

by Sara Marques Coelho Leiterholt
Doctoral thesis
Date of Examination:2016-11-14
Date of issue:2016-10-31
Advisor:PD Dr. Gunther Helms
Referee:PD Dr. Katharina Hein
Referee:Prof. Dr. Rainer Mausberg
Persistent Address: http://dx.doi.org/10.53846/goediss-5907

 

 

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Abstract

English

Magnetic resonance imaging is an important method to diagnose and evaluate the progression of MS. SIENA is a program package for the analysis of brain volume change, especially atrophy. In the present study we used the SIENA method to longitudinally evaluate the brain volume change in MS patients. MRI scans were performed every six months over two years in a study population of 34 MS patients and 12 normal subjects. The MS group consisted of 20 patients with RRMS, 11 with SPMS and 3 patients without specification of the phenotype. We found that all groups showed standard deviations that were large compared to the mean changes. Thus, there was no statistically significant brain atrophy in the MS groups. To explain these results by specific features of SIENA, we performed further analysis of serial MRI scans in controlled cases. In one patient with Marburg’s variant of MS errors were due to inaccuracy in tissue segmentation. The brain growth of an infant paediatric patient could only be shown after correcting the initial SIENA results with volume scaling. After applying this scaling correction to the study cohorts, however, the results showed an even larger standard deviation. In the analysis of consecutive MRI scans of the MS group we found that individual outliers in the series were responsible for the large spreading of the results. The validity of the SIENA method was demonstrated by the authors Smith et al. using a transitivity analysis. Our analysis shows that this approach to validation reduces the impact of individual outliers. Despite the inaccuracy observed in our study group, we were able to reproduce the transitivity results. A larger data collection period with additional MRI scans and thus the possibility to identify and eliminate outliers would be needed to evaluate the brain volume change with the SIENA method in MS patients.
Keywords: multiple sclerosis; brain atrophy; SIENA
Schlagwörter: Multiple Sclerose; Gehirnatrophie; SIENA
 
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