http://brain.oupjournals.org/cgi/content/abstract/124/12/2540
Brain, Vol. 124, No. 12, 2540-2549,
December 2001
Marco Rovaris (1), Marco Bozzali
(1), Giuseppe Santuccio (1), Angelo Ghezzi (9), Domenico Caputo (3), Enrico
Montanari (4), Antonio Bertolotto (5), Roberto Bergamaschi (6), Ruggero
Capra (7), Gianluigi Mancardi (8), Vittorio Martinelli (2), Giancarlo Comi
(2) and Massimo Filippi (1)
1 Neuroimaging Research Unit and
2 Clinical Trials Unit, Department
of Neuroscience, Scientific Institute and University Ospedale San Raffaele,
3 Department of Neurology, Scientific
Institute Don Gnocchi, University of Milan, Milan,
4 Multiple Sclerosis Center, Ospedale
di Fidenza, Fidenza,
5 Department of Neurology, Ospedale
di Orbassano, Orbassano,
6 Department of Neurological Sciences,
Scientific Institute C. Mondino, University of Pavia, Pavia,
7 Department of Neurology, Spedali
Civili, University of Brescia, Brescia,
8 Department of Neurological Sciences,
University of Genoa, Genoa
9 Multiple Sclerosis Center, Ospedale
di Gallarate, Gallarate, Italy
Abstract
In patients with primary progressive
(PP) multiple sclerosis, brain MRI lesion activity and burden are low,
despite the presence of severe neurological impairment.
On the contrary, the degree of cord
atrophy and diffuse tissue damage in the brain and cervical cord have been
found to be associated with clinical disability.
Against this background, this study
aimed at providing an in vivoindirect assessment of brain and cervical
cord pathology in a large cohort of PP multiple sclerosis patients, using
conventional MRI and magnetization transfer imaging (MTI).
Ninety-one PP multiple sclerosis
patients, 36 secondary progressive (SP) multiple sclerosis patients and
30 healthy controls underwent brain and cervical cord MRI scans, using
dual echo (brain) or fast short-tau inversion recovery (cervical cord)
MTI and T1-weighted sequences.
For the brain, T2 hyperintense and
T1 hypointense lesion volumes were calculated and the volume of the whole
of the brain tissue measured. For the cervical cord, the number and burden
of lesions and the cross-sectional area were assessed.
MTI scans were post-processed and
analysed to obtain magnetization transfer ratio (MTR) histograms from the
whole of the brain and cervical cord tissue and from the normal-appearing
brain tissue in isolation.
In PP multiple sclerosis patients,
brain, normal-appearing brain tissue and cervical cord MTR histogram-derived
metrics revealed the presence of diffuse tissue damage whose characteristics
did not significantly differ from those of SP multiple sclerosis patients,
even though SP multiple sclerosis patients had higher MRI-visible lesion
burdens.
None of the correlations between
MRI or MTI measures obtained from the brain and the cord were significant.
PP multiple sclerosis patients' disability
was significantly, albeit weakly associated with a composite MR model including
measures of loss and intrinsic damage of cervical cord tissue.
Our data indicate the presence of
a diffuse tissue damage undetectable by conventional MRI in PP multiple
sclerosis patients, whose extent seems to match that of SP multiple sclerosis
patients with similar levels of disability.
They also suggest that the severity
of multiple sclerosis pathology in the cervical cord is one of the factors
contributing to neurological impairment in PP multiple sclerosis.
Copyright © 2001 Oxford University
Press.