CORRELATING MRI AND CLINICAL-DISEASE ACTIVITY IN MULTIPLE-SCLEROSIS -RELEVANCE OF HYPOINTENSE LESIONS ON SHORT-TR SHORT-TE (T-1-WEIGHTED) SPIN-ECHO IMAGES
Maa. Vanwalderveen et al., CORRELATING MRI AND CLINICAL-DISEASE ACTIVITY IN MULTIPLE-SCLEROSIS -RELEVANCE OF HYPOINTENSE LESIONS ON SHORT-TR SHORT-TE (T-1-WEIGHTED) SPIN-ECHO IMAGES, Neurology, 45(9), 1995, pp. 1684-1690
Magnetic resonance imaging (MRI) is being used as an outcome criterion
in therapeutic trials in multiple sclerosis (MS) on the assumption th
at it, as a sensitive marker of biologic disease activity, could serve
as a surrogate marker of disability. We evaluated the relation betwee
n MRI findings and disability in a quantitative followup study of 48 M
S patients. Median duration of follow-up was 24 months (range, 10 to 4
2 months). Computer-assisted volume measurements employing a seed-grow
ing technique yielded a standard error of measurement of 0.275 cm(2).
The median total area of the hyperintense lesions on the initial T-2-w
eighted images was 8.4 cm(2). The median increase was 0.76 cm(2)/yr (9
%). In a subgroup (n = 19) with short-TR/short-TE spin-echo (SE) image
s, we measured the hypointense lesion load. The median total area of t
he lesions at entry was 0.70 cm(2), with a median increase of 0.28 cm(
2)/yr (40%). The total area of the hyperintense lesions on the initial
T-2-weighted images showed a weak correlation with the Expanded Disab
ility Status Scale score at entry (Spearman rank correlation coefficie
nt [SRCC] = 0.30; 0.02 <p < 0.05). The increase in disability showed a
positive correlation (SRCC = 0.19) with the increase in hyperintense
lesion load on the T-2-weighted SE images, but this correlation did no
t reach statistical significance (p = 0.09), probably because of lack
of clinical progression. The number of active lesions detected by visu
al analysis of the T-2-weighted SE images correlated significantly (SR
CC = 0.40; 0.001 < p < 0.01) with the number of relapses during the in
terval between the initial and follow-up imaging examinations. The sub
group with short-TR/short-TE SE images (whose disease was clinically m
ore active than the group as a whole) showed a significant correlation
of increased disability with increase in hypointense lesion load (SRC
C = 0.74; p < 0.002). Our results, and those from previous follow-up s
tudies, suggest a positive correlation between MRI and clinical activi
ty, but extended follow-up studies are needed to confirm the appropria
teness of quantitative MRI as a surrogate marker of disability in MS.
Short-TR/short-TE SE images seem to be more relevant than T-2-weighted
SE images in identifying the lesions that cause disability.