The effect of aging on the apparent diffusion coefficient of normal-appearing white matter

AJR Am J Roentgenol. 2000 Aug;175(2):425-30. doi: 10.2214/ajr.175.2.1750425.


Objective: The purpose of our study was to test the hypothesis that the apparent diffusion coefficient (ADC) of normal-appearing white matter increases with advancing age.

Subjects and methods: We selected 38 patients with normal MR imaging findings from 332 patients undergoing clinical MR imaging. Diffusion-weighted MR imaging was performed with diffusion gradients applied in three orthogonal directions. For each patient, the average ADC on trace-weighted diffusion images of white matter at prespecified regions of interest and at the thalamus were compared with the patient's age.

Results: For the white matter, ADC sorted by patient age in decades increased with advancing age. Patients at least 60 years old had significantly higher ADC (0.769 +/- 0.019 mm(2)/sec x 10(-3)) than patients less than 60 years old (0.740 +/- 0.013 mm(2)/sec x 10(-3)) (p < 0.001). Comparison of individual white matter ADC and age showed a significant increase with advancing age (p < 0.0001). For the thalamus, the average ADC among patients at least 60 years old (0.766 +/- 0.015 mm(2)/sec x 10(-3)) exceeded the average ADC for patients less than 60 years old (0.745 +/- 0.022 mm(2)/sec x 10(-3)) (p < 0.05). However, comparison of individual thalamic ADC and patient ages, although showing a trend to higher ADC with increasing age, did not reach statistical significance (p = 0.06).

Conclusion: Advancing age is associated with a small but statistically significant increase of water diffusibility in human white matter. A similar trend was present in the thalamus. These increases may reflect mild structural changes associated with normal aging.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aging*
  • Brain / anatomy & histology*
  • Diffusion
  • Female
  • Humans
  • Magnetic Resonance Imaging*
  • Male
  • Middle Aged
  • Thalamus / anatomy & histology