SOME METHODOLOGICAL ISSUES IN NEURORADIOLOGICAL RESEARCH IN PSYCHIATRY

An outline is given of some of the methodological issues discussed in neuroradiological research on psychiatric illness. Strengths and short comings of magnetic resonance imaging (MRI) in depicting and quantifyi ng brain structures are described. Temporal lobe anatomy and pathology are easily accessible to MRI, whereas limits on anatomical delineatio n hamper approaches to frontal lobe study. White matter hyperintense l esions are sensitively depicted by MRI, but specificity is limited. Di stinction of vascular and primary degenerative dementia is considerabl y improved by CT and MRI analysis. Computed tomography (CT) and MRI ha ve enhanced the understanding of treatable organic psychiatric disorde rs, e.g., normal pressure hydrocephalus. Subcortical and white matter pathology has been replicated in CT and MRI studies of late-onset psyc hiatric disorders, clinical overlap with cerebrovascular disease or ne urodegeneration may be of import. Transcranial sonography findings of brainstem structural change specific to unipolar depression may contri bute to the understanding of affective psychoses. Magnetic resonance s pectroscopy and functional MRI are likely to stimulate psychiatric res earch in the future.