Microscopic MRI

For the purposes of this review we define microscopic MRI as studies with spatial resolution on the order of 100 pm or less and will concentrate on developments since 1999. We recommend texts by Callaghan, Mansfield and Morris, Morris, Vlaardingerbroek and den Boer and Haacke et al. Two... 

The bottom image in Figure 2.2.15 is a maximum intensity projection of a 100 xm cubic-resolution 3D-image dataset of a blue berry acquired with this system. The network structure of the fruit is clearly visualized. If the MRI console and permanent magnet can be made smaller, a true desktop or handy M R microscope will then be constructed. 

While it is possible to perform rheo-NMR in large scale MRI systems, the use of microscopic geometries with sub-millilitre volumes is highly desirable, especially where expensive speciality materials are to be examined. Such sample volumes... 

Clinical signs, brain MRI and microscope investigation of skin or lymphocytes... 

There is a very cogent reason to believe that the atrophy found on CT scans cannot be the product of schizophrenia. Brain atrophy is far more accurately and definitively evaluated by a direct postmortem pathological examination than on a CT or MRI brain scan. The actual pathology, if it exists, can more easily be identified and accurately measured by direct observation and microscopic analyses. 

An autopsy can also obtain tissue slices for examination with a light microscope or an electron microscope. Furthermore, on gross examination of the brain, instead of estimating tissue loss from MRI pictures, an autopsy can actually weigh and measure the brain and examine cell density under the microscope. As a result, many diseases of the brain, such as Alzheimer s, require an autopsy rather than an MRI or CT scan to make the definitive diagnosis (Caine et al., 1995). 

Magnetic resonance imaging (MRI) is finding increasing application in areas that require microscopic resolution. While typical resolutions employed clinically are on the order of a millimeter, the notion of using MRI at microscopic resolutions arose... 

The bio-heat transfer equation with both of these assumptions has been solved for various tissue geometries and initial and boundary conditions (Shitzer and Eberhart, 1985). Because of scalar treatment of the convective heat transport by blood, the use of the bio-heat transfer equation has been questioned repeatedly (Charny, 1992). Considering tissue as porous media, Wulff (1974, 1980) introduced the blood velocity vector ub, in the bio-heat transfer equation. Unfortunately, the complex nature of the system defies any attempt to specify the circulation vector at the microscopic level. As non-invasive technologies (e.g., MRI) provide improved spatial resolution, it may be possible to incorporate such data numerically (Dutton et al., 1992). 

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