PET-CT case of the month (09/09): Alzheimer's Disease
This case was compiled by Dr. Sabeen Rahman (BCM)
A 64 year old male with memory problems for last seven years presents with
severe progressive dementia. MRI of the brain showed moderate cortical
volume loss and non-specific periventricular white matter changes
secondary to small vessel disease.
severe progressive dementia. MRI of the brain showed moderate cortical
volume loss and non-specific periventricular white matter changes
secondary to small vessel disease.
F 18 FDG Brain PET-CT shows cortical atrophy and moderate to
severely decreased metabolism in the bilateral posterior temporo-parietal
regions, worse on the right. Mild decreased activity is also noted in the
frontal regions. There is sparing of the sensori-motor cortex with normal
distribution in the occipital region, sub cortical structures and the
cerebellum.
severely decreased metabolism in the bilateral posterior temporo-parietal
regions, worse on the right. Mild decreased activity is also noted in the
frontal regions. There is sparing of the sensori-motor cortex with normal
distribution in the occipital region, sub cortical structures and the
cerebellum.
In early Alzheimer’s diseases, PET findings relate to hypometabolism in
the bilateral parietotemporal regions, which can often be asymmetric. In
more advanced disease, the frontal lobes also show decreased FDG
uptake. CT and MRI show ventricular and cortical atrophy, which has
been used to diagnose DAT, but studies have shown that PET is more
sensitive than MRI or CT to detect cortical involvement in dementia.
1. Franz Fazekas, Abass Alavi et al. Comparison of CT, MR, and PET in
Alzheimer's Dementia and Normal Aging. JNM 1989; 30: 1607-1615.
the bilateral parietotemporal regions, which can often be asymmetric. In
more advanced disease, the frontal lobes also show decreased FDG
uptake. CT and MRI show ventricular and cortical atrophy, which has
been used to diagnose DAT, but studies have shown that PET is more
sensitive than MRI or CT to detect cortical involvement in dementia.
1. Franz Fazekas, Abass Alavi et al. Comparison of CT, MR, and PET in
Alzheimer's Dementia and Normal Aging. JNM 1989; 30: 1607-1615.
Alzheimer’s’ disease or Dementia of Alzheimer’s type (DAT) is strongly
suggested in this patient due to the classic finding of reduction in the
bilateral posterior parieto-temporal regions and sparing of the
sensorimotor cortex. Decreased metabolism in the frontal regions is
suggestive of advanced Alzheimer’s disease.
suggested in this patient due to the classic finding of reduction in the
bilateral posterior parieto-temporal regions and sparing of the
sensorimotor cortex. Decreased metabolism in the frontal regions is
suggestive of advanced Alzheimer’s disease.
