ADC Measurements in Various Patterns of Multiple Sclerosis Lesions
Warinthorn Phuttharak MD*, Waneerat Galassi MD**, Vallop Laopaiboon MD*, Malinee Laopaiboon PhD***, John R Hesselink MD, FACR****
Affiliation : * Department of Radiology, Faculty of Medicine, Khon Kaen University, Khon Kaen ** Department of Radiology, Faculty of Medicine, Naresuan University, Phitsanulok *** Department of Biostatistics, Faculty of Public Health, Khon Kaen University, Khon Kaen **** Department of Radiology, UCSD Medical Center, San Diego, California, USA
Objective : To determine the difference of mean apparent diffusion coefficients (ADC) among different patterns
of focal multiple sclerosis (MS) lesions, to compare mean lesion ADC between 2 clinical subgroups and to
correlate mean lesion ADC with disability.
Materials and Methods : Thirty seven patients (26 with relapsing-remitting multiple sclerosis (MS) and 11 with
secondary-progressive MS) underwent both conventional and diffusion-weighted MR imaging of the brain.
After creating ADC maps, region identification was done by using b = 0 images and T2-weighted images. ADC
values were measured for MS lesions and (NAWM).
Results : A total of 288 lesions were identified on the images. The mean ADC for the lesions was significantly
higher than that of NAWM. Hypointense T1 lesions (n = 221) had a significantly higher mean ADC than
isointense T1 lesions (n = 67) in both nonenhancing lesions (n = 250) and enhancing lesions (n = 38). The
enhanced rim of ring-enhancing lesions (n = 18) had lower ADC than the central nonenhanced portions.
Confluent lesions (n = 62) had a substantially higher mean ADC than discrete lesion (n = 226). Mean lesion
ADC of secondary progressive MS was significantly higher than relapsing remitting MS. No correlation
between mean lesion ADC and (EDSS) score was found.
Conclusion : Quantitative diffusion-weighted imaging is useful to elucidate the heterogeneous pathological
substrate of MS in different patterns of MS lesions, to differentiate 2 major clinical subgroups.
Keywords : Multiple sclerosis, Echo-planar diffusion-weighted imaging, Apparent diffusion coefficient (ADC), Normal appearing white matter (NAWM), Expanded disability status scale (EDSS)
