Whole magnetic resonance imaging

Warach S, Gaa J, Siewert B, Wielopolski P, Edelman RR. Acute human stroke studied by whole brain echo planar diffusion-weighted magnetic resonance imaging. Ann Neurol 1995 37 231-241. 

Magnetic Resonance Imaging on whole body units provides visualization of tissue inside slices with a thickness of several millimetres. The spatial resolution in the plain is often better than one millimetre so that even relatively small structures can be well depicted. However, the spatial resolution is not sufficient to resolve the microscopic structures mentioned in Section 2. Only the cross-sections of single muscles and septa from fatty tissue or cormective tissue can be visualized in MR images recorded from humans in vivo. 

The helium supply seemed secure, but then scientists discovered a whole new application for the gas. Helium boils at the lowest temperature of any substance (-269°C) and it never solidifies. Liquid helium is therefore the ideal substance to cool electrical wires and reduce their resistance to the flow of the current. It has allowed us to manufacture superconducting magnets, which have diverse applications, but probably none more useful than in magnetic resonance imaging. This technology affords doctors a noninvasive look inside the human body, and it Is probably the most important medical diagnostic tool ever developed. The future of mri, however, hinges on the availability of helium. Think about that the next time you fill those birthday balloons with the gas. 

The speed with which NMR spectroscopy has been incorporated into scientific inquiry is truly amazing. The first commercial spectrometers became available in the 1950s. By the middle 1980s whole bodies could be placed in the probes of NMR spectrometers (magnetic resonance imaging) and the structures of body parts could be determined in exquisite detail. Today structures of proteins and other macromolecules in solution or in the solid state are determined routinely. What was unthinkable in the 1960s is routinely practiced today even by undergraduates The power of the method and the structural detail it provides have no doubt fueled its rapid development. 

Mehta, M.P. et al. (2002) Lead-in phase to randomized trial of motexafin gadolinium and whole-brain radiation for patients with brain metastases centralized assessment of magnetic resonance imaging, neurocognitive, and neurologic end points, J. Clin. Oncol. 20, 3445-3453. 

Two imaging systems, dual energy X-ray absorptiometry scanning (DEXA) and magnetic resonance imaging (MRI), allow for longitudinal studies of whole body composition. DEXA measures bone mineral density and content, fat content, and lean content in anesthetized mice. Echo MRI from Echo Medical System, Houston, TX, is used to measure whole body composition parameters such as total body fat, lean mass, body fluids, and total body water in live mice without the need for anesthesia or sedation (15). The MRI technology is more rapid, less than a minute to scan one mouse, than DEXA which takes about 5 min per mouse. 

Schlemmer HP, Schafer J, Pfannenherg C, Radny P, Kor-chidi S, Muller-Horvat C, N de T, Tomaschko K, Fenchel M, Claussen CD (2005) Fast whole-body assessment of metastatic disease using a novel magnetic resonance imaging system initial experiences. Invest Radiol 40 64-71... 

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