There are a variety of types of dementia and cognitive impairment, which can have various underlying causes, ranging from Alzheimer’s disease (AD) to vascular dementia to name but a few, requiring different therapeutical approaches. Hence various risk factors need to be assessed. While imaging and laboratory tests have traditionally been used independently on a diagnostic basis to rule out other causes of dementia, they may in the future help to assess multiple different aspects of AD pathology and have immediate prognostic importance. Siemens provides technology and laboratory equipment to help effectively differentiate AD from other dementias and venture forward in AD research.
The ɛ4 allele of the apolipoprotein E (APOE) gene has been identified as a major genetic risk factor for AD. It encodes a protein that plays a key role in cholesterol metabolism and has been found to increase the risk of developing AD. APOE-ɛ4 contributes to AD pathogenesis seems to act primarily as a risk factor in brain beta-amyloid deposition.1 Hence, screening for APOE gene mutations and micro RNA pattern indicating a risk profile will become important screening tools in the future.
In patients with suspected AD, the clinical evaluation essentially includes lab tests for a number of mimicking diseases such as hypo- and hyperthyroidism, vitamin deficiencies, and infections of the central nervous system (Creutzfeldt-Jakob disease, AIDS dementia, neurosyphilis). As your partner in thyroid testing, Siemens solutions help labs keep pace with the evolving standards in thyroid disease diagnostics.
Brain scans are used to rule out other possible causes of dementia, including brain tumors, stroke, subdural hematomas, normal-pressure hydrocephalus, and other conditions. Non-contrast and contrast-enhanced CT imaging is a highly efficient neuro-imaging technique that provides differential and cause-related information on possible causes of dementia. The unmatched soft tissue contrast of MRI and additional information gained from dedicated sequences enables to reliably rule out differential diagnoses. With state-of-theart CT and MR scanners together with software for all your clinical and research related data handling, Siemens is the ideal partner in AD image based evaluation.
The simultaneous acquisition of MR imaging (MRI)/ CT imaging and positron emission tomography (PET) data provides exceptional insights into brain anatomy, functions, and metabolism. Biograph mMR and Biograph mCT/Biograph mCT Flow have the ability to precisely visualize areas of decreased or increased glucose metabolism in the brain. This supports differentiation between AD, frontoemporal dementia and other dementias. It also allows a determination of the extent and progression of the disease. In AD, a characteristic pattern of decreased uptake can be seen in the posterior temporo parietal association cortex.1 PET imaging is utilized to estimate beta-amyloid neuritic plaque density in adult patients with cognitive impairment who are being evaluated for AD and other causes of cognitive decline.2 Through the combination of CT or MR with PET in one modality, Siemens technology enables shorter acquisition times and optimizes accuracy with motion compensation in agitated patients. Siemens’ exceptional molecular PET/MR and PET/CT technology promises unprecedented insights into AD pathology, more comprehensive brain imaging, and improved functional analysis.
1Clifford R. J. Alzheimer disease: New Concepts on Its Neurobiology and the Clinical Role Imaging Will Play. Radiology 2012;263 (2): 344-361
2Adam S. Fleisher et al: “Using Positron Emission Tomography and Florbetapir F 18 to Image Cortical Amyloid in Patients With Mild Cognitive Impairment or Dementia Due to Alzheimer Disease”, Archives of Neurology, July 12, 2011