What is the role of CT scanning in the workup of Alzheimer disease (AD) in Down syndrome (DS)?

Updated: Nov 13, 2019
  • Author: Norberto Alvarez, MD; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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Studies that used computed tomography (CT) to compare young individuals who had Down syndrome (DS) (19-34 y) with a comparable group of healthy individuals who did not have mental retardation found no significant differences between the 2 groups with respect to white- or gray-matter volumes or ventricular volumes. [84]

Quantitative studies with CT scanning and magnetic resonance imaging (MRI) demonstrated that young adults with DS have no ventricular dilatation, no atrophy, and no consistent malformation that could explain the mental retardation. However, small brain size was reported consistently. This is probably an expression of small stature and a small cranial vault. [84]

Bilateral symmetric basal ganglia calcification is a frequent finding in people with DS (see the images below); in fact, it is more prevalent in this population than in the general population. However, its relationship with the clinical presentation of Alzheimer disease (AD) in DS is unclear.

CT scan of a man who has Down syndrome confirmed b CT scan of a man who has Down syndrome confirmed by chromosomal analysis. He has a long history of mental deterioration with progressive loss of ability to perform his usual activities. The CT scan, obtained when the patient was aged 60 years and exhibiting advanced signs of Alzheimer disease, shows several calcified areas in the basal ganglia plus diffuse cortical atrophy and enlargement of the ventricular system. The bilateral symmetric calcifications are a frequent finding in this condition.
CT scan of a man who has Down syndrome confirmed b CT scan of a man who has Down syndrome confirmed by chromosomal analysis. He has a long history of mental deterioration with progressive loss of ability to perform his usual activities. The CT scan, obtained when the patient was aged 60 years and exhibiting advanced signs of Alzheimer disease, shows several calcified areas in the basal ganglia plus diffuse cortical atrophy and enlargement of the ventricular system. The bilateral symmetric calcifications are a frequent finding in this condition.
CT scan of a man who has Down syndrome confirmed b CT scan of a man who has Down syndrome confirmed by chromosomal analysis. He has a long history of mental deterioration with progressive loss of ability to perform his usual activities. The CT scan, obtained when the patient was aged 60 years and exhibiting advanced signs of Alzheimer disease, shows several calcified areas in the basal ganglia plus diffuse cortical atrophy and enlargement of the ventricular system. The bilateral symmetric calcifications are a frequent finding in this condition.

The results were different when people with DS and cognitive deficiencies were compared with individuals who did not have cognitive deficiencies. In individuals with DS and cognitive deficiencies, cerebral atrophy and ventricular enlargement that suggested brain atrophy were reported consistently (see the images below).

CT scan of a 62-year-old man with Down syndrome co CT scan of a 62-year-old man with Down syndrome confirmed by chromosomal analysis. This CT scan was obtained when he was showing signs of moderate-to-advanced Alzheimer disease. The CT scan shows marked, diffuse enlargement of the ventricular system and generalized atrophy of the cerebral cortex.
CT scan of a 62-year-old man with Down syndrome co CT scan of a 62-year-old man with Down syndrome confirmed by chromosomal analysis. This CT scan was obtained when he was showing signs of moderate-to-advanced Alzheimer disease. The CT scan shows marked, diffuse enlargement of the ventricular system and generalized atrophy of the cerebral cortex.
CT scan of a 62-year-old man with Down syndrome co CT scan of a 62-year-old man with Down syndrome confirmed by chromosomal analysis. This CT scan was obtained when he was showing signs of moderate-to-advanced Alzheimer disease. The CT scan shows marked, diffuse enlargement of the ventricular system and generalized atrophy of the cerebral cortex.

In advanced cases, atrophy was generalized. However, regional differences can exist with greater involvement of the temporal horns. The relation between enlargement of the temporal horns of the lateral ventricles and dementia in elderly DS patients has been a consistent feature.


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