Introduction

Recent research into late life mental disorders has revealed a host of structural and functional changes in the brains of elderly psychiatric patients. It now is clear that those with structural changes (such as increased atrophy on CT or WMHI on MRI) have a different prognosis from depressed or demented patients without such changes. Several studies also have established that patients with late life depression have characteristic global decreases in cerebral perfusion and metabolism that may distinguish them from those with dementia.

These research findings help to elucidate the pathophysiology of late-life mental disorders and may explain some of the heterogeneity in presentation and prognosis. Our ability to image the brain, however, has in some cases outpaced our ability to understand the clinical implications of the structural and functional findings seen using modern neuroimaging techniques.

Clinical application of neuroimaging techniques has flourished since the early 1970s, seemingly under the basic principle of ‘the more we know, the better care will be’. With increasing emphasis on medical cost containment, the utilization of these technologies and usefulness of their results must be scrutinized more carefully. Which of the structural and functional findings seen with modern neuroimaging techniques have clinical utility?

CT and MRI scanning

Structural imaging using CT or MRI commonly is performed to screen for reversible mass lesions (meningiomas, subdural hematomas) or irreversible lesions (deep tumors, strokes) that could be contributing to or causing a psychiatric illness.