March 15, 2007 The older people become, the greater risk they have of sharing the tragic fate of those who remain alive yet are increasingly unaware of the world around them. In industrialised countries, one to six percent of the population over the age of 65 and an even more alarming ten to twenty percent over the age of 80 suffer a progressive loss of their cognitive abilities. Alzheimers disease is the most common cause, affecting 50 to 60 percent of all cases, followed by circulatory disorders in small blood vessels, capillaries and venules (calcifications), which make up about 20 percent. These disorders cause ever larger parts of the brain to become necrotic due to an insufficient supply of blood.
The earlier these disorders and their causes are detected, the more effective the therapies can be for preventing the disease or at least substantially slowing down its progress. Increasingly higher-resolution imaging techniques making major contributions to early detection are now being presented at the European Congress of Radiology (ECR 2007), held in Vienna from March 9 to 13, 2007, and attended by some 16,000 participants from 92 countries. University Professor Dr. Daniela Prayer from the Clinical Department for Neuroradiology at the Vienna University of Medicine states, “Although we cannot yet depict individual cells, we can image ultra-tiny bundles of fibre with high resolution. That is a spectacular breakthrough!”
Voxel-based morphometry allows for the volume of grey matter and white matter in the brain to be determined to the nearest cubic millimetre. A reduction in brain mass (atrophy) in certain areas indicates Alzheimer’s disease and in other areas, other forms of dementia, according to Professor Prayer. An MR study by Professor Dr. Riccardo della Nave and his colleagues at the University of Florence, for instance, found that certain degenerative phenomena occurring in the left thalamus and in a zone in the left cerebral cortex are the first signs of family-related Alzheimer’s disease. “These findings are quite valuable. They enable us not only to differentiate precisely but also to detect the patterns of the disease before symptoms even occur and to check the efficacy of new drugs, namely, whether they can really stop the loss of brain mass.”
Another advance allows insights into the circuitry architecture of individual bundles of cerebral fibre. It is based on special techniques applicable with modern magnetic resonance devices to render visible the movements of water molecules in the space between fibres. Professor Prayer explains, “Wherever protons change direction, there has to be an obstacle, a cell wall or a fibre connection. Applying the reverse conclusion, we obtain a picture of these structures and see early on where swelling occurs or cells die off.”
No less fascinating are the prospects opened up by magnetic resonance spectroscopy (MRS). It allows a non-contact x-ray view of biochemical processes within the regions of the brain under examination. Changes in metabolism detectable by using this method enable neurologists to distinguish clearly between the onset of Alzheimer=E2=80=99s disease, a mild cognitive impairment, MCI, and normal, non-pathological aging.
All in all, Professor Prayer notes, “the new methodological advances of magnetic resonance technology provide us with a hopeful view of the future in terms of the early diagnosis and efficacy testing of therapies for dementias. If this happens in the near future, the spectre of old-age dementia will lose much of its threatening effect.”