Diffusion-weighted imaging characteristics of biopsy-proven demyelinating brain lesions

Neurology. 2012 May 22;78(21):1655-62. doi: 10.1212/WNL.0b013e3182574f66. Epub 2012 May 9.


Objectives: To describe lesional diffusion-weighted imaging characteristics in a cohort of patients with biopsy-proven CNS inflammatory demyelinating disease (IDD) and compare diffusion characteristics of ring-enhancing CNS IDD lesions vs abscesses and tumors.

Methods: Forty prebiopsy apparent diffusion coefficient (ADC) maps were reviewed from 30 patients with CNS IDD. Lesions were analyzed for size, T2-weighted (T2W) hypointense rim, enhancement, and ADC pattern. ADC patterns of CNS IDD ring-enhancing lesions were compared with a published cohort of 35 patients with ring-enhancing tumors and abscesses.

Results: IDD lesions displayed a spectrum of peripheral ADC patterns at the lesion edge: restricted diffusion (low ADC), 33%; increased diffusion (high ADC), 60%; and normal diffusion (homogeneously isointense), 7%. Of biopsied lesions, 93% enhanced (ring, 52%; heterogeneous, 34%; homogeneous, 7%). A hypointense T2W rim was observed in 53%. A ring pattern on ADC (isointense or dark) was associated with T2W hypointense rims (p = 0.02) but not with ring enhancement. On serial imaging, 4 of 7 (57%) patients demonstrated changes in ADC patterns. Peripheral restriction was more common in IDD (p = 0.006) than in tumors or abscesses, whereas central restriction was only observed in abscesses. Restricted lesions in the same stage were more common in the non-IDD cohort (42% vs 20%), with a uniform restricted pattern seen only in abscesses.

Conclusions: In ring-enhancing lesions, peripheral diffusion restriction is more common in IDD than in tumors/abscesses, whereas central restriction is more common among abscesses. Rapid ADC pattern changes in IDD probably reflect dynamic lesion evolution and may distinguish IDD from tumors.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscess / diagnosis
  • Abscess / pathology
  • Adolescent
  • Adult
  • Aged
  • Cohort Studies
  • Demyelinating Diseases / diagnosis*
  • Demyelinating Diseases / immunology
  • Demyelinating Diseases / pathology
  • Diffusion Magnetic Resonance Imaging / methods*
  • Female
  • Humans
  • Inflammation / classification
  • Inflammation / diagnosis
  • Inflammation / pathology
  • Male
  • Middle Aged
  • Neoplasms / diagnosis
  • Neoplasms / pathology
  • Retrospective Studies
  • Single-Blind Method
  • Young Adult