From GE Healthcare;
the New Signa Profile/i is a patient friendly open MRI system that virtually eliminates patient anxiety and claustrophobia, without compromising diagnostic utility.

GE Healthcare is the result of the merger between GE Medical and Amersham Health in Nov. 2004, after GE acquired Amersham Health for 9.5 billion in Oct. 2003. Jeffrey R. Immelt, Chairman of the Board and Chief Executive of General Electric, said, 'Amersham's diagnostic pharmaceutical and life sciences business will add new, high growth platforms to GE Medical's diagnostic imaging, services and healthcare information technology businesses'. GE Healthcare, a UK company, is a unit of General Electric (NYSE: GE). GE Healthcare is a global leader in medical imaging, diagnostic imaging contrast agents, interventional procedures, healthcare services, and information technology. For more than 100 years, health care providers have relied on GE Medical Systems, now GE Healthcare, for high quality medical technology and productivity solutions. GE Healthcare, headquartered now at formerly seat of Amersham Health in Great Britain, operates facilities around the world. Global Operations include organizations on the Americas, Europe, and Asia, including India, Japan, Korea China, Thailand and Vietnam.

MRI Scanners:

0.2T to 1.0T:
to 1.5T:
to 3.0T:

MRI Contrast Agents:

(FAIR) In this sequence 2 inversion recovery images are acquired, one with a nonselective and the other with a slice selective inversion pulse. The z-magnetization in the first sequence is independent of flow. Inflowing spins give z-magnetization from second pulse. A major signal loss in FAIR is the T1 relaxation of tagged blood in transit to the imaging slice. Sharper edges of the inversion pulse give narrow spacing between the inversion edge and the 1st slice because reduced transit time gives lower T1 relaxation induced signal loss. The difference of the images in a consequence contains information proportional to flow (blood partition coefficient). Standard adiabatic inversion RF pulse does not have good slice-profile, because of power/SAR limitation. A c-shaped frequency offset corrected inversion (FOCI) RF pulse can help to increase the signal.
Perfusion imaging, e.g. myocardial, using tissue water as endogenous contrast is suggested.

(FWHM) A commonly used measure of the width at half the maximum value of peaked functions such as spectral lines or slice profiles and important measure of the quality of an imaging device and its spatial resolution. As the name states, the FWHM is measured by identifying the points on the signal curve, which are half the maximum value. The horizontal distance between these two points is called the FWHM. For a spectral line, this will be proportional to 1/T2.

(THK) The thickness of an imaging slice. As the slice profile may not be sharp edged, a criterion such as the distance between the points at half the sensitivity of the maximum (FWHM) or the equivalent rectangular width (the width of a rectangular slice profile with the same maximum height and same area) is used to determine thickness.

For the image quality its important to choose the best fitting slice thickness for an examination. When a small item is entirely contained within the slice thickness with other tissue of differing signal intensity then the resulting signal displayed on the image is a combination of these two intensities. If the slice is the same thickness or thinner than the small structure, only that structures signal intensity is displayed on the image. This partial volume averaging effect explains the vanishing of fine details by choosing slices too large for the scanned object.

See also Partial Volume Artifact.