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[IM‐02]: Basic principles of spectroscopy, and perfusion weighted imaging
Author(s) -
Schuff Norbert W.
Publication year - 2005
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2005.06.042
Subject(s) - dementia , magnetic resonance imaging , arterial spin labeling , neuroimaging , medicine , perfusion , neuroscience , in vivo magnetic resonance spectroscopy , perfusion scanning , positron emission tomography , alzheimer's disease , in vivo , nuclear medicine , pathology , disease , psychology , radiology , biology , microbiology and biotechnology
In this course, the physical principles of magnetic resonance (MR) spectroscopy, which detects cerebral metabolites and arterial spin labeling (ALS) magnetic resonance imaging (MRI), which can measure regional brain perfusion, are reviewed. Furthermore, applications of MR spectroscopy and ASL-MRI as they relate to neuroimaging studies in aging, Alzheimer’s disease (AD) and in other types of dementia are discussed. Both techniques are entirely non-invasive, do not require injection of tracers, and can be performed in the same session together with anatomical MRI, providing complementary information to structural brain alterations. In AD, MRS studies consistently revealed diminished concentrations of N-acetylaspartate (NAA), an in-vivo marker of viable neurons, axons, and dendrites as well as increased levels of myo-inositol (MI), a proposed marker for glial activation. More than a dozen MRS studies in various brain disorders, including AD have also reported recovery of diminished NAA after pharmaceutical intervention, suggesting MRS might help assessing therapeutic outcomes in trials of brain dysfunction. ASL-MRI, on the other hand, is a relatively new technique and there have been only a few ASL-MRI studies in aging and dementia. Initial results demonstrated that ASL-MRI reveals a stereotypical regional pattern of cerebral hypoperfusion in AD, similar to the patterns observed with SPECT and PET. Moreover, ASL-MRI showed regional hypoperfusion already in mild cognitively impaired subjects, who are at increased risk for AD, suggesting that early signs of AD before clinical symptoms develop may be detected using ASL-MRI. Further improvements in accuracy and reliability of metabolite and perfusion measurements are expected with high magnetic field applications of MRS and ALS-MRI. However, both techniques also face several obstacles at high magnetic fields. Both benefits and pitfalls of high magnetic field MRS and ASL-MRI will also be discussed.