In vivo detection of cortical plaques by MR imaging in patients with multiple sclerosis.
OBJECTIVE
In vivo detection of cortical lesions in patients with multiple sclerosis (MS) by MR imaging is hampered by several factors. Among them is the low contrast between small cortical lesions and surrounding cortical gray matter offered by present techniques.


METHODS
T1-weighted 3D spoiled gradient-recalled-echo (SPGR) volumes and 2D fluid-attenuated inversion recovery (FLAIR) sequences of 22 patients with MS who had 12 monthly brain MR imaging examinations at 1.5T, using a quadrature head coil, were retrospectively analyzed. These serial studies were coregistered and averaged to generate a single high signal-to-noise ratio (SNR) mean image, which was used to identify cortical lesions. The means of 12 FLAIRs and SPGRs from 14 age- and sex-matched healthy volunteers were analyzed as well.


RESULTS
No cortical lesions were found on images of healthy subjects. Eighty-six cortical lesions were identified in 13 (59.1%) patients, predominantly in the frontal lobe (73.3%); 23.3% of cortical lesions lay entirely in the cortex, whereas the remaining lesions invaded the white matter underneath.


CONCLUSIONS
Averaging multiple SPGRs created a single high SNR volume, allowing identification of cortical lesions. Because data were obtained monthly for 1 year, the average image does not account for transient lesion activity. However, for cortical lesions that remained stable during this time, the findings are valid in demonstrating the importance of high SNR images for detecting cortical brain abnormalities in MS.
Bagnato
F
F
Neuroimmunology Branch, NINDS, Warren G. Magnuson Clinical Center, NIH, Bethesda, MD 20892-1400, USA. bagnatof@ninds.nih.gov
Butman
J A
JA
Gupta
S
S
Calabrese
M
M
Pezawas
L
L
Ohayon
J M
JM
Tovar-Moll
F
F
Riva
M
M
Cao
M M
MM
Talagala
S L
SL
McFarland
H F
HF
D000328:Adult; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology*; D012189:Retrospective Studies