Advanced

AJNR - American Journal of Neuroradiology

A, CT scan obtained 4–5 hours after surgery does not show any significant abnormalities and was interpreted as normal.

B, T2-weighted MR image (windowed at 700/500) obtained 48–72 hours after the hypoxic-ischemic episode illustrates mildly pronounced gray–white matter differentiation of the cerebral hemispheres and gyral swelling.

C, TurboFLAIR image (windowed at 650/400) demonstrates similar findings as those on the T2-weighted image, with mildly pronounced gray–white matter differentiation.

D, DW image with initial window/level (improper window/level of 1000/400) that is not in keeping with our usual window/level (250/150) shows that the diffuse cortical abnormality is obscured. Although improperly windowed, there is pronounced gray–white matter differentiation, not usually present on DW images (see Fig 2).

E, The abnormality is more distinct on this properly windowed DW image (windowed at 250/150), which shows diffuse uniform cortical and caudate hyperintensity with accentuation of the gray–white matter interface.

F, ADC map demonstrates severe, uniform, cortical restricted diffusion (mean ADC value, 0.31 x 10^–3 mm²/s as measured in the perirolandic cortex in this patient) that was interpreted as cortical laminar necrosis. Electroencephalogram obtained the next day (3 days after cardiorespiratory arrest) was interpreted as electrocerebral silence, and support was withdrawn per request of the patient’s family.

A and B, Properly windowed (250/150) DW image (A) versus an improperly windowed (850/400) DW image (B) in patient 5. Note the prominent gray–white matter differentiation even on the improperly windowed DW image in B.

C, Properly windowed DW image in a neurologically normal 40-year-old man for comparison shows that the gray–white matter differentiation is usually not so accentuated on DW images in a neurologically normal patient.

A, T2-weighted image (windowed at 700/500) illustrates mildly pronounced gray–white matter differentiation of the cerebral hemispheres and gyral swelling.

B, TurboFLAIR image (windowed at 650/400) demonstrates similar findings as those on the T2-weighted image, with mildly pronounced gray–white matter differentiation.

C, Improper window/level (1150/650) obscures the diffuse cortical abnormality on this DW image. Although improperly windowed, there is accentuated gray–white matter differentiation, not usually present on DW images (as in Figs 1 and 2).

D, DW image with proper window/level of 250/150 shows that the cortical abnormality is more evident. The caudate nucleus (although slightly hyperintense) did not demonstrate as severely restricted diffusion as that in patient 1.

E, ADC map further illustrates the symmetric and uniform cortical restricted diffusion, with less prominent diffusion abnormality in the deep gray nuclei.