Early Alzheimer’s disease can be suggested by specific findings on a CT scan, although CT is less sensitive than MRI or PET for early detection. On CT imaging, the primary features that may indicate early Alzheimer’s include **mild to moderate brain atrophy**, especially in the **medial temporal lobes**, which encompass the hippocampus and entorhinal cortex—regions critical for memory formation. This atrophy appears as widening of the temporal horns of the lateral ventricles and enlargement of the surrounding cerebrospinal fluid spaces. Additionally, **generalized cortical atrophy** may be seen, but it is less specific.
CT may also reveal **ventricular enlargement** beyond what is expected for age, reflecting loss of brain tissue. However, these changes are subtle in early stages and can overlap with normal aging or other neurodegenerative conditions, making CT alone insufficient for definitive early diagnosis.
More advanced imaging techniques, such as MRI with specialized sequences, can detect **microstructural changes** and **iron accumulation** in key brain areas like the entorhinal cortex and putamen years before symptoms appear. These iron-related changes are linked to neurodegeneration and can predict progression to mild cognitive impairment, a precursor to Alzheimer’s. PET scans, which assess brain metabolism and amyloid protein deposits, are even more sensitive in detecting early functional and molecular changes that CT cannot visualize.
In summary, on a CT scan, early Alzheimer’s disease may be suggested by:
– **Atrophy of the medial temporal lobes**, especially hippocampal shrinkage
– **Enlargement of temporal horns of lateral ventricles**
– **Generalized cortical atrophy** with widened sulci
– **Ventricular enlargement** disproportionate to age
These findings reflect loss of neurons and brain tissue but are subtle and nonspecific in early disease. More sensitive imaging modalities like MRI with quantitative susceptibility mapping or PET scans provide earlier and more specific detection of Alzheimer’s-related brain changes, including iron accumulation and amyloid deposition, which precede visible structural atrophy on CT.
Therefore, while CT can show structural brain changes suggestive of early Alzheimer’s, it is often used in conjunction with clinical evaluation and more advanced imaging to improve early diagnosis and guide treatment decisions.
