The Effect of Aging on the Apparent Diffusion Coefficient of Normal-Appearing White Matter
Stefan T. Engelter1,2,3,
James M. Provenzale1,
Jeffrey R. Petrella1,
David M. DeLong1 and
James R. MacFall1
1
Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC
27710.
2
Department of Medicine, Division of Neurology, Duke University Medical Center,
Durham, NC 27710.
3
Present address: Department of Neurology, University Hospital, Petersgraben 4,
4031 Basel, Switzerland.
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Fig. 1A. —65-year-old man who underwent MR imaging for evaluation of tinnitus.
T2-weighted image shows small hyperintense white matter focus
(arrow), which was excluded from region of interest drawn to
determine mean apparent diffusion coefficient (ADC) of normal-appearing white
matter.
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Fig. 1B. —65-year-old man who underwent MR imaging for evaluation of tinnitus.
ADC map at same level as that seen in A shows white matter lesion
(arrow) as hyperintense region as result of presence of increased
diffusibility in site of chronic ischemia. Mean ADC was 0.912
mm2/sec x 10-3 for lesion, 0.762
mm2/sec x 10-3 for white matter, and 0.781
mm2/sec x 10-3 for thalamus. Inclusion of such
hyperintense foci would have resulted in higher mean ADC values than were
found in this study.
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Fig. 2A. —63-year-old man with dizziness. Axial spin-echo T2-weighted MR image
through level of basal ganglia and thalamus shows no lesions in white matter
or gray matter structures.
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Fig. 2B. —63-year-old man with dizziness. Average apparent diffusion
coefficient (ADC) map at same level as that seen in A displays spatial
distribution of average ADC measured in three orthogonal diffusional
directions. Locations of regions of interest (ROIs) in white matter (ROIs 1-4)
and thalamus (ROIs 5 and 6) that were chosen for calculation of patient's mean
ADC values are shown.
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Fig. 3. —Scatter diagram of apparent diffusion coefficient (ADC) for white
matter plotted against patient age shows increase in ADC with advancing age
(p < 0.0001).
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Fig. 4. —Box-and-whisker plot for mean apparent diffusion coefficient (ADC)
of white matter and patient age by decade shows lower mean values for patients
in third decade compared with those in seventh decade (p < 0.05)
and those in eighth decade (p < 0.001). Whiskers indicate standard
deviation of mean ADC in each age decade.
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Fig. 5. —Scatter diagram of thalamic apparent diffusion coefficient (ADC)
plotted against patient age shows trend to higher ADC with advancing age,
which did not reach statistical significance (p = 0.6).
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Fig. 6. —Box-and-whisker plot for mean thalamic apparent diffusion
coefficient (ADC) and patient age by decade shows no significant differences
in mean ADC among age decades (p > 0.05). Whiskers indicate
standard deviation of mean ADC within each decade.
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Copyright © 2000 by the American Roentgen Ray Society.
