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Reliability of two techniques for assessing cerebral iron deposits with structural magnetic resonance imaging
Author(s) -
Valdés Hernández Maria C.,
Jeong Tina H.,
Murray Catherine,
Bastin Mark E.,
Chappell Francesca M.,
Deary Ian J.,
Wardlaw Joanna M.
Publication year - 2011
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22361
Subject(s) - fluid attenuated inversion recovery , thresholding , segmentation , multispectral image , magnetic resonance imaging , computer science , voxel , artificial intelligence , reliability (semiconductor) , pattern recognition (psychology) , confidence interval , nuclear medicine , mathematics , medicine , radiology , statistics , physics , image (mathematics) , quantum mechanics , power (physics)
Purpose To test the reliability of two computational methods for segmenting cerebral iron deposits (IDs) in the aging brain, given that its measurement in magnetic resonance imaging (MRI) is challenging due to the similar effect produced by other minerals, especially calcium, on T2*‐weighted sequences. Materials and Methods T1‐, T2*‐weighted, and fluid‐attenuated inversion recovery (FLAIR) MR brain images obtained at 1.5T from 70 subjects in their early 70s who displayed a wide range of brain IDs were analyzed. The first segmentation method used a multispectral approach based on the fusion of two or more structural sequences registered and mapped in the red/green color space followed by Minimum Variance Quantization. The second method employed a combined thresholding, size and shape analysis using T2*‐weighted images augmented with visual information from T1‐weighted data. Results Both segmentation techniques had high intra‐ and interobserver agreement (95% confidence interval [CI] = ± 57 voxels in a range from 0 to 1800), which decreased in subjects with significant microbleeds and/or IDs. However, the thresholding method was more observer dependent in identifying microbleeds and IDs boundaries than the multispectral approach. Conclusion Both techniques proved to be in agreement and have good intra‐ and interobserver reliability. However, they have limitations, specifically with regard to automation and observer independence, so further work is required to develop fully user‐independent methods of identifying cerebral IDs. J. Magn. Reson. Imaging 2011;33:54–61. © 2010 Wiley‐Liss, Inc.