Sequential diffusion-weighted magnetic resonance imaging study of lysophosphatidyl choline-induced experimental demyelinating lesion: an animal model of multiple sclerosis.
OBJECTIVE
To differentiate the surrounding edema from the focal demyelinating lesion during the early phase of the lesion using an apparent diffusion coefficient (ADC), and to monitor the changes in ADCs during the complete progression of a lysophosphatidyl choline (LPC)-induced experimental demyelinating lesion, an animal model of multiple sclerosis (MS).


METHODS
Eighteen rats divided into two groups-demyelinating lesion (group I, N = 12) and vehicle group (saline injected; group II, N = 6)-were studied. A 0.2-microl quantity of 1% LPC solution in isotonic saline was injected in the rat brain internal capsule (IC) area to create the demyelinating lesion. Six rats were used exclusively for histology. Diffusion-weighted (DW) images were acquired at different diffusion weightings on the 3rd, 5th, 10th, 15th, and 20th days after LPC injection. ADC was measured from three regions of interest (ROIs) within the IC: focal demyelinating lesion (area A), surrounding area of the lesion (area B), and contralateral IC area (area C).


RESULTS
Histology revealed demyelination of the IC area during the early phase of lesion progression up to day 10 and remyelination thereafter. Elevated ADCs were observed for the surrounding edematous area (area B), compared to the focal demyelinating lesion (area A) during the early phase of the demyelination process, while substantial reduction of ADCs was noticed during remyelination for both regions.


CONCLUSIONS
Measurement of ADC showed clear differentiation of the surrounding edema from the LPC-induced focal demyelinating lesion in rats, especially during the early phase of the lesion progression.
Department of NMR, All India Institute of Medical Sciences, New Delhi, India.
Mahaveer N
MN
Degaonkar
Rama
R
Jayasundar
Naranamangalam R
NR
Jagannathan
D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000473:pathology*; D003711:Demyelinating Diseases / Q000139:chemically induced / Q000175:diagnosis* / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D004195:Disease Models, Animal; D008244:Lysophosphatidylcholines; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric
D008244:Lysophosphatidylcholines