Differentiation of calcified regions and iron deposits in the ageing brain on conventional structural MR images

del C. Valdés Hernández, M., Glatz, A., Kiker, A. J., Dickie, D. A. , Aribisala, B. S., Royle, N. A., Muñoz Maniega, S., Bastin, M. E., Deary, I. J. and Wardlaw, J. M. (2014) Differentiation of calcified regions and iron deposits in the ageing brain on conventional structural MR images. Journal of Magnetic Resonance Imaging, 40(2), pp. 324-333. (doi: 10.1002/jmri.24348) (PMID:24923620)

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Abstract

Purpose: In the human brain, minerals such as iron and calcium accumulate increasingly with age. They typically appear hypointense on T2*‐weighted MRI sequences. This study aims to explore the differentiation and association between calcified regions and noncalcified iron deposits on clinical brain MRI in elderly, otherwise healthy subjects. Materials and Methods: Mineral deposits were segmented on co‐registered T1‐ and T2*‐weighted sequences from 100 1.5 Tesla MRI datasets of community‐dwelling individuals in their 70s. To differentiate calcified regions from noncalcified iron deposits we developed a method based on their appearance on T1‐weighted images, which was validated with a purpose‐designed phantom. Joint T1‐ and T2*‐weighted intensity histograms were constructed to measure the similarity between the calcified and noncalcified iron deposits using a Euclidean distance based metric. Results: We found distinct distributions for calcified regions and noncalcified iron deposits in the cumulative joint T1‐ and T2*‐weighted intensity histograms across all subjects (correlations ranging from 0.02 to 0.86; mean = 0.26 ± 0.16; t = 16.93; P < 0.001) consistent with differences in iron and calcium signal in the phantom. The mean volumes of affected tissue per subject for calcified and noncalcified deposits were 236.74 ± 309.70 mm3 and 283.76 ± 581.51 mm3; respectively. There was a positive association between the mineral depositions (β = 0.32, P < 0.005), consistent with existing literature reports. Conclusion: Calcified mineral deposits and noncalcified iron deposits can be distinguished from each other by signal intensity changes on conventional 1.5T T1‐weighted MRI and are significantly associated in brains of elderly, otherwise healthy subjects.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Dickie, Dr David Alexander
Authors: del C. Valdés Hernández, M., Glatz, A., Kiker, A. J., Dickie, D. A., Aribisala, B. S., Royle, N. A., Muñoz Maniega, S., Bastin, M. E., Deary, I. J., and Wardlaw, J. M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Journal of Magnetic Resonance Imaging
Publisher:Wiley
ISSN:1053-1807
ISSN (Online):1522-2586
Published Online:29 October 2013

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