This absence of hippocampal atrophy is one of the conspicuous findings in AD one can encounter. Other findings and their associated proposed alternative diagnoses are listed in Table IV. Figure 3. AD patient with early onset (age 51). On the left pronounced parietal and posterior cingulate atrophy is seen, while in the right panel a coronal cut of the same patient shows an intact medial temporal Inhibitors,research,lifescience,medical lobe. Table IV. Conspicuous MRI/CT findings in patients suspected of having AD. (See list of abbreviations

at the beginning of this article) Serial ME imaging Besides the existence of regional atrophy, the most important structural imaging feature of AD is progression of atrophy. A yearly decline in hippocampal volume approximately 2.5 times greater in patients with AD than in normal aged subjects is reported, and a relationship Inhibitors,research,lifescience,medical exists between memory loss

and hippocampal damage across the spectrum from normal aging to dementia. Neuroanatomical changes over time may be too mild, diffuse, or topographically complex to be detected by simple visual inspection, or even with manually traced measurements of regions of interest. New serial volumetric imaging techniques developed in the last few years represent an added value to identify subtle structural brain changes, Inhibitors,research,lifescience,medical which have brought extensive neocortical changes to the fore, extending well beyond the medial temporal lobe.6 Vascular changes Besides atrophy, cerebrovascular pathology has been associated with AD, especially in the late Inhibitors,research,lifescience,medical onset form. As such, overlap with vascular dementia (VaD) may occur and patients may actually fulfil criteria for both AD and VaD. Unfortunately, no operational criteria for so-called mixed dementia exist, so it is left to the judgement of the clinician, which label fits best with the clinical picture of the patient. Further, use of PET or CSF may help to tease out the relevant pathologies. In AD most often

Inhibitors,research,lifescience,medical signs of small-vessel disease are present on MRI in the form of white matter hyperintensities (WMFI), lacunar infarcts (lacunes) (Figure 2,Figure 5) and microbleeds (Figure 6) . Microbleeds have been associated with amyloid angiopathy, but their clinical relevance is still uncertain. Figure 4. Cerebrovascular pathology on axial fluid attenuated mafosfamide inversion Abiraterone molecular weight recovery (FLAIR) MRI scans. Confluent white matter changes (Fazekas scale 3). Figure 5. Cerebrovascular pathology on axial fluid attenuated inversion recovery (FLAIR) MRI scans. Lacunar infarcts in basal ganglia on both sides. Figure 6. Microbleeds on Flash/T2*/2D axial MRI scan. On the left, predominantly in the basal ganglia; on the right, predominantly located cortically. Functional (molecular) imaging Positron emission tomography Brain metabolism can be studied using PET. Changes in brain metabolism may precede structural brain changes. Glucose metabolism can be visualized using the metabolic tracer [18F]fluorodeoxyglucose (FDG).