Magnetic resonance imaging and computed tomography in Alzheimer's disease

Modern imaging techniques such as X-ray computed tomography (CT) and magnetic resonance imaging (MRI) are widely used in the clinical evaluation of patients with dementia disorders. Computed tomography was introduced for clinical practice in the beginning of the 1970s. The advent of MRI came later with the first equipment used for clinical purposes being introduced in the first half of the 1980s. The two modalities differ in many aspects: CT has a lower contrast resolution compared with MRI and is also faster and often more convenient for patients. In contrast, MRI gives a superior picture of the brain tissue without the use of contrast agents. Moreover, MRI, like CT, does not suffer from bone artifacts. The latter is of special importance in the study of dementia diseases (especially Alzheimer's) where structural changes are present close to the brain. The possibility of image in arbitrary imaging planes also makes MRI more suitable to study structures of relevance in Alzheimer's disease such as the medial temporal lobes and the hippocampal formation.