Multiple Sclerosis,
October 2001,
vol. 7, no. 5, pp. 298-304(7)
Sormani M.P. [2]; Bruzzi P. [1];
Rovaris M. [2]; Barkhof F. [4]; Comi G. [3]; Miller D.H. [5]; Cutter G.R.
[6]; Filippi M. [2] *
[1] Unit of Clinical Epidemiology
and Trials, National Institute for Cancer Research, Genoa, Italy
[2] Neuroimaging Research Unit,
Department of Neuroscience, Scientific Institute Ospedale and University
San Raffaele, Milan, Italy
[3] Clinical Trials Unit, Department
of Neuroscience, Scientific Institute Ospedale and University San Raffaele,
Milan, Italy
[4] Dutch MS/MR Center, Free University
Hospital, Amsterdam, The Netherlands
[5] NMR Research Unit, Institute
of Neurology, London, UK
[6] Center for Research Methods
and Biometrics, AMC Cancer Research Center, Lakewood, Colorado, USA
[*] Correspondence: M Filippi, Neuroimaging
Research Unit, Department of Neuroscience, Scientific Institute and University
Ospedale san Raffaele, Via Olgettina 60, 20132 Milan, Italy
Abstract:
Magnetic resonance imaging (MRI)
has been established as the most relevant paraclinical tool for diagnosing
and monitoring multiple sclerosis (MS).
In this context, counting the number
of new enhancing lesions on monthly MRI scans is widely used as a surrogate
marker of MS activity when evaluating the effect of treatments.
In this study, we investigated whether
parametric models based on mixed Poisson distributions (the Negative Binomial
(NB) and the Poisson-Inverse Gaussian (P-IG) distributions) were able to
provide adequate fitting of new enhancing lesion counts in MS.
We found that the NB model gave good
approximations in relapsing — remitting and secondary progressive MS patients
not selected for baseline MRI activity, whereas the P-IG distribution modelled
better new enhancing lesion counts in relapsing – remitting MS patients
selected for baseline activity.
This study shows that parametric
modelling for MS new enhancing lesion counts is feasible.
This approach should provide more
targeted tools for the design and the analysis of MRI monitored clinical
trials in MS.
© 2001 ingenta