Diagnostic imaging of dementia in the elderly.

Dementia is a frequent problem in elderly patients. More than age per se, it may influence the indication for invasive diagnostic and therapeutic procedures to treat other diseases. Here, the role of tomographic imaging methods for differential diagnosis of dementia will be reviewed briefly, with the new possibilities that became available recently. Computed tomography (CT) of the brain is used primarily to detect potentially treatable conditions, such as multiple ischemic infarcts, hematomas, hydrocephalus and brain tumors. It should be performed even at higher age if the general condition of the patient is good enough not to exclude all specific therapeutic measures. Magnetic resonance imaging (MRI) is more sensitive for ischemic white matter lesions and hippocampal atrophy and should therefore used preferentially in mildly affected patients. Functional imaging methods, such as single photon emission computed tomography (SPECT) and positron emission tomography (PET), are necessary only in clinically unclear cases to demonstrate functional impairment of association cortex.