Cerebral Cortical Neurodegeneration

Case A: A brain FDG-PET examination shows markedly asymmetric cortical hypometabolism primarily involving the temporal and parietal lobes that is much more pronounced in the left hemisphere than in the right hemisphere. The parietal lobe involvement is most pronounced inferiorly and is contiguous with hypometabolism in the left temporal lobe. Relative (although not absolute) sparing of the primary somatic motor and sensory cortices is observed, including the perirolandic regions and occipital lobes bilaterally.

Case B: A brain FDG-PET examination shows heterogeneous asymmetric cortical metabolism most pronounced in the parietal, occipital, and temporal lobes bilaterally. Relative sparing of the frontal lobes is observed. In light of the normal intense metabolic activity in the occipital lobes, the marked deficit seen here indicates a severe abnormality in this region.

Case C: A brain FDG-PET examination shows marked cortical hypometabolism that is most pronounced within the frontal and temporal lobes bilaterally, with asymmetrically greater involvement on the right than on the left. Relative sparing of the primary somatic motor and sensory cortices is observed, including the perirolandic regions and occipital lobes bilaterally.

Case D: A brain FDG-PET examination demonstrates marked and heterogeneous hypometabolism involving both cortical and deep gray matter structures. The cortical involvement is asymmetric, with greater involvement on the left than on the right, and somewhat patchy in distribution, with abnormality involving the frontal, temporal, parietal, and occipital lobes. Prominent involvement of the primary somatic motor and sensory cortices is observed. The caudate, putamen, and thalami are profoundly, although variably, affected.

Case E: A brain FDG-PET examination shows heterogeneous cortical hypometabolism throughout the cerebral hemispheres, with profound involvement of the occipital lobes bilaterally and less severe involvement in the frontal, temporal, and parietal lobes.

Case F: Results of head MRI (axial fluid attenuated inversion recovery) and brain FDG-PET examinations are shown, with PET and MRI images co-registered on the left. Multiple regions of hypometabolism of varying size are observed in the cerebrum and cerebellum bilaterally. Foci of hypometabolism (large on the right and small on the left) are seen in the cerebellar hemispheres, corresponding to small foci of infarction seen on the MRI. Focal hypometabolism is noted in the left occipital lobe and in the lateral aspect of the right postcentral gyrus, both of which correspond to areas of encephalomalacia on the MRI consistent with chronic infarction.