Mapping of iron deposition in conjunction with assessment of nerve fiber tract integrity in amyotrophic lateral sclerosis.
OBJECTIVE
To test if and where increased iron accumulation occurs in amyotrophic lateral sclerosis (ALS) by quantitative mapping of iron deposition and to relate these findings to white matter tract degeneration assessed by diffusion tensor imaging (DTI).


METHODS
Fifteen patients with ALS and 15 age- and gender-matched controls underwent MRI of the brain to obtain R(2)* relaxation rate and DTI measurements, focusing on the corticospinal tract (CST) and on deep gray matter structures, using tract-based spatial statistics (TBSS).


RESULTS
Compared with controls, ALS patients showed reduced fractional anisotropy values along the mesencephalic CST, suggesting disintegration of fiber tracts. A trend for R(2)* values to be elevated was found in the CST of ALS patients. Regarding other brain areas examined, increased R(2)* values in ALS patients were observed solely in the caudate nucleus.


CONCLUSIONS
This study extends previous findings on fiber disorganization by additional quantitative evidence for increased iron deposition in closely localized regions along the CST in ALS patients. Longitudinal studies are needed to further explore the pathophysiologic and diagnostic implications of these findings.
Department of Neurology, Medical University of Graz, Austria.
Christian
C
Langkammer
Christian
C
Enzinger
Stefan
S
Quasthoff
Paula
P
Grafenauer
Michaela
M
Soellinger
Franz
F
Fazekas
Stefan
S
Ropele
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000473:pathology*; D001921:Brain / Q000473:pathology; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007501:Iron / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*
D007501:Iron