Article Figures & Data
Figures
- Fig 1.
Initial MR imaging in a 15-year-old girl with perinatally acquired human immunodeficiency virus infection. T2-weighted fast spin-echo image shows hyperintense confluent area of demyelination (A) within the right parietooccipital white matter with extension into the right cingulate gyrus. The overlying cortex is spared. In addition, multiple punctuate T2-hyperintense lesions are seen throughout the entire right hemisphere. On diffusion tensor imaging, the parietooccipital T2-hyperintense lesion is centrally diffusion-weighted hypointense (B) and apparent diffusion coefficient (ADC) hyperintense (C), whereas the periphery of the lesion is diffusion-weighted hyperintense and ADC hypointense (rim of cytotoxic edema). On the fractional anisotropy map (D), the degree of anisotropy is markedly reduced. In addition, multiple small diffusion weighted–hyperintense, ADC-hypointense punctuate lesions are seen within the right hemisphere, compatible with multiple small foci of active inflammation with tissue injury.
- Fig 2.
Follow-up MR imaging 13 months later. Axial T2-weighted fast spin-echo image (A) shows an extensive T2-hyperintense destruction of the right hemispheric white matter with global atrophy. In addition, new focal T2-hyperintense lesions are seen within the left hemisphere. Diffusion-weighted imaging (B) shows a hypointensity with corresponding ADC hyperintensity (C) of the white matter within the right hemisphere as a result of extensive tissue injury and necrosis. No lesions with active inflammation (ADC hypointensity) are seen.
Tables
Measured ADC and FA values in comparison with age-matched normative data
Region ADC FA Normal ADC Normal FA Occipital WM L 981 ± 69 0.28 ± 0.11 890 ± 110 0.33 ± 0.10 Occipital WM R 927 ± 59 0.10 ± 0.03 890 ± 110 0.33 ± 0.10 Frontal WM L 961 ± 30 0.33 ± 0.06 900 ± 50 0.31 ± 0.08 Frontal WM R 970 ± 45 0.25 ± 0.05 900 ± 50 0.31 ± 0.08 Centrum semiovale L 938 ± 24 0.38 ± 0.04 830 ± 40 0.39 ± 0.07 Centrum semiovale R 982 ± 48 0.24 ± 0.05 830 ± 40 0.39 ± 0.07 Parietal WM L 941 ± 74 0.32 ± 0.10 860 ± 60 0.32 ± 0.09 Parietal WM R 954 ± 49 0.09 ± 0.02 860 ± 60 0.32 ± 0.09 Caps. int. post. L 924 ± 42 0.58 ± 0.02 750 ± 40 0.63 ± 0.04 Caps. int. post. R 963 ± 52 0.47 ± 0.03 750 ± 40 0.63 ± 0.04 Splenium 998 ± 51 0.57 ± 0.06 940 ± 240 0.64 ± 0.09 WM lesion center 1845 ± 187 0.06 ± 0.02 830–900 ± 40–110 0.31–0.39 ± 0.07–0.10 WM lesion peripheral rim 490 ± 120 0.20 ± 0.06 830–900 ± 40–110 0.31–0.39 ± 0.07–0.10 WM focal lesions (mean) 480 ± 89 0.19 ± 0.05 830–900 ± 40–110 0.31–0.39 ± 0.07–0.10 Note.—ADC indicates apparent diffusion coefficient (mm2/s); FA, fractional anisotropy; WM, white matter; Caps. int. post., capsula interior posterior limb; L, left; R, right. FA values are scalar indices ranging from 0 to 1, where 0 represents maximal isotropic diffusion, as in a sphere, and 1 represents maximal anisotropic diffusion, as in the hypothetical case of a long cylinder of minimal diameter. Normative, age-matched ADC and FA values, which are paired with their SDs, were extracted from the literature.
