The range of diagnostics and imaging systems of Siemens Medical Systems covers ultrasound, nuclear medicine, angiography, magnetic resonance, computer tomography and patient monitoring. Siemens is one of the three leading MRI manufacturers, which together account for approximately 80 percent of the MRI machines installed worldwide. Siemens currently offers the Allegra 3T MRI, which is for head scanning only, but the company will also be launching the Trio MRI, a 3T whole body scanner.
Siemens has formed partnerships with more than ten research institutions and private practitioners to define a comprehensive MRI examination and compare MR to currently established cardiovascular modalities, thereby defining optimal diagnosis and treatment.

MRI Scanners:

0.2T to 1.0T:
1.5T:
3.0T to 7.0T:
Hybrid Scanners:
Mobile Solutions:

(USPIO) The class of the ultrasmall superparamagnetic iron oxide includes several chemically and pharmacologically very distinct materials, which may or may not be interchangeable for a specific use. Some ultrasmall SPIO particles (median diameter less than 50nm) are used as MRI contrast agents (Sinerem®, Combidex®), e.g. to differentiate metastatic from inflammatory lymph nodes. USPIO shows also potential for providing important information about angiogenesis in cancer tumors and could possibly complement MRI helping physicians to identify dangerous arteriosclerosis plaques.
Because of the disadvantageous large T2*//T1 ratio, USPIO compounds are less suitable for arterial bolus contrast enhanced magnetic resonance angiography than gadolinium complexes. The tiny ultrasmall superparamagnetic iron oxides do not accumulate in the RES system as fast as larger particles, which results in a long plasma half-life. USPIO particles, with a small median diameter (less than 10 nm), will accumulate in lymph nodes after an intravenous injection by e.g. direct transcapillary passage through endothelial venules. Once within the nodal parenchyma, phagocytic cells of the mononuclear phagocyte system take up the particles.
As a second way, USPIOs are subsequently taken up from then interstitium by lymphatic vessels and transported to regional lymph nodes. A lymph node with normal phagocytic function takes up a considerable amount and shows a reduction of the signal intensity caused by T2 shortening effects and magnetic susceptibility. Caused by the small uptake of the USPIOs in metastatic lymph nodes, they appear with less signal reduction, and permit the differentiation of healthy lymph nodes from normal-sized, metastatic nodes.

See also Superparamagnetic Contrast Agents, Superparamagnetic Iron Oxide, Very Small Superparamagnetic Iron Oxide Particles, Blood Pool Agents, Intracellular Contrast Agents.

Chemical shift depends on the nucleus and its environment and is defined as nuclear shielding / applied magnetic field. Nuclei are shielded by a small magnetic field caused by circulating electrons, termed nuclear shielding. The strength of the shield depends on the different molecular environment in that the nucleus is embedded. Nuclear shielding is the difference between the magnetic field at the nucleus and the applied magnetic field.
Chemical shift is measured in parts per million (ppm) of the resonance frequency relative to another or a standard resonance frequency.
The major part of the MR signal comes from hydrogen protons; lipid protons contribute a minor part. The chemical shift between water and fat nuclei is about 3.5 ppm (~220 Hz; 1.5T). Through this difference in resonance frequency between water and fat protons at the same location, a misregistration (dislocation) by the Fourier Transformation take place, when converting MR signals from frequency to spatial domain. This effect is called chemical shift artifact or chemical shift misregistration artifact.

Founded in 1969, Elscint is headquartered in Haifa, Israel. Elscint developed advanced computerized imaging systems in Computed Tomography (CT), Magnetic Resonance Imaging (MRI), Nuclear Medicine (NM) and Mammography (MAM) for international markets.
In November 1998, General Electric Medical Systems (GEMS) acquired the Nuclear Medicine and MRI divisions of Elscint, including an unique MRI gradient system concept and technology (twin gradient system).
Elscint Ltd. signs definitive agreement to sell its Nuclear Medicine and Magnetic Resonance Imaging Businesses for $100 Million. Elscint's shareholders approved the sale of its NM, and MRI division to GE (now GE Healthcare). Picker International acquires the Computed Tomography Division of Elscint Ltd. in the same year.

See also Marconi Medical Systems.

Inert hyperpolarized gases are under development for imaging air spaces, including those in the lungs. Because they mostly contain air and water, lungs are difficult organs to image.
These ventilation agents (gases) have potential in lung imaging and are currently used in studies of the pulmonary ventilation:
Specific isotopes of inert gases can be hyperpolarized. Hyperpolarized is a state in which almost all of the atoms nuclei are spinning in the same direction. Once the nuclei in the isotope 3He have been hyperpolarized using a laser, they remain in this state for several days. The inert, hyperpolarized gas can then be used in a lung imaging study, where the high concentration of polarized nuclei provides a sharp contrast in MRI. The technique is already being developed with a view to commercialization by Magnetic Imaging Technologies in Durham, North Carolina. According to the company, existing MRI equipment can be used with a few minor modifications, along with a gas polarizer. The technique could provide early detection and monitoring of pulmonary disease.
Hyperpolarized 129Xe can also be used as a magnetic resonance tracer because of its MR-enhanced sensitivity combined with its high solubility. This isotope differs from 3He in that it can dissolve in the blood. Strong enhancement of the nuclear spin polarization of xenon in the gas phase can be achieved by optical pumping of rubidium and subsequent spin-exchange with the xenon nuclei. This technique can increase the magnetic resonance signal of xenon by five orders of magnitude, thus allowing NMR detection of xenon in very low concentration. MR spectroscopy and imaging of optically polarized xenon shows considerable potential for medical applications (see also back projection imaging).
Nycomed Amersham anticipated the market for inert gases in pulmonary imaging. The company obtained an exclusive license for the use of helium (He) and xenon (Xe) as MRI contrast agents. Currently, the US FDA has not yet approved the commercial distribution of inert gas imaging equipment, because the technique is still undergoing trials.