[Diagnostic imaging techniques in the investigation of dementia]

Neuroimaging can provide valuable information in the diagnostic work-up of patients presenting with suspected dementia.

Based on our experience from a memory clinic at Ullevål University Hospital in Oslo, Norway and on relevant literature identified on Medline, we give an overview of the use of neuroimaging methods in patients with suspected dementia.

CT of the brain should be offered to all patients with suspected dementia as CT can provide essential diagnostic information regarding focal cerebral pathology (tumour, haemorrhage, normal pressure hydrocephalus). A CT scan is of no value in the diagnostic evaluation of patients with mild to moderate Alzheimer's disease as age-related atrophy may be a confounding factor. CT is necessary to reveal infarcts when vascular dementia is suspected, but lacks sensitivity in the detection of diffuse cerebrovascular disease. MRI is recommended in younger patients and may be used to diagnose subcortical lesions, e.g. leukoariosis. The accuracy of SPECT in the assessment of patients with cognitive impairment is not yet established though it seems to be a promising method for the detection of frontotemporal dementia. Functional MR may play a role in the work-up of dementia in the future.