FIG 1. Images of a patient who experienced cardiorespiratory arrest of unknown cause at age 2.5 months. The infant died 18 days after the event.

A, Axial spin-echo T2-weighted image (3700/150), obtained 28 hours after the event (class A), shows mild cortical and white matter hyperintensity, consistent with edema, and mild focal cortical T2 hypointensity (long arrows). Watershed areas score, 1/4. Fuzzy hyperintense areas (short arrow) are also seen in the posterior lentiform nuclei. Basal ganglia score, 1/4; total MR imaging score, 2/8.

B, Axial spin-echo T2-weighted image (3700/150), obtained 16 days after the event (class C). Diffuse T2 hyperintensity and loss of gray-white matter differentiation are consistent with severe cortical and white matter involvements. Focal cortical T2 hypointensity was also seen. Watershed areas score, 4/4. Prominent involvements in all the basal ganglia are present in caudate nuclei, lentiform nuclei, and thalami as important signal intensity modifications (abnormal hyperintense and hypointense areas). Basal ganglia score, 4/4. There is, moreover, an involvement in the posterior limb of the internal capsule as T1 and T2 prolongation (arrow). Total MR imaging score, 8/8.

C, Axial inversion-recovery T1-weighted image (1600/600/35), obtained 16 days after the event (class C). T1 hyperintensity was also seen. Watershed areas score, 4/4. Prominent involvements in all the basal ganglia are present in caudate nuclei, lentiform nuclei, and thalami as important signal intensity modifications (abnormal hyperintense and hypointense areas). Basal ganglia score, 4/4. There is, moreover, an involvement in the posterior limb of the internal capsule as T1 and T2 prolongation (arrow). Total MR imaging score, 8/8.