In-vivo assessment of tissue metabolite levels using 1H MRS and the Electric REference To access In vivo Concentrations (ERETIC) method.

Quantitative values of metabolite concentrations in (1)H magnetic resonance spectroscopy have been obtained using the Electric REference To access In vivo Concentrations (ERETIC) method, whereby a synthetic reference signal is injected during the acquisition of spectra. The method has been improved to enable quantification of metabolite concentrations in vivo. Optical signal transmission was used to eliminate random fluctuations in ERETIC signal coupling to the receiver coil due to changes in position of cables and highly dielectric human tissue. Stability and reliability of the signal were tested in vitro, achieving stability with a mean error of 2.83%. Scaling of the signal in variable loading conditions was demonstrated and in-vivo measurements of brain were acquired on a 3T Philips system using a transmit/receive coil. The quantitative brain water and metabolite concentration values are in good agreement with those in the literature.

Interactive reduced FOV imaging for projection reconstruction and spiral acquisition.

MR fluoroscopy is likely to gain increasing importance for the visualization of dynamic processes such as cardiac function and for the guidance of interventional procedures. In many applications the dynamic processes are restricted to a part of the object under study making reduced field of view (rFOV) imaging desirable. The restriction to a smaller FOV can either be used to increase the spatial or the temporal resolution. In projection reconstruction (PR) and spiral imaging severe backfolding artifacts occur if a rFOV is used. In this paper efficient suppression schemes are proposed for PR- and spiral imaging to avoid backfolding artifacts. Evaluation of the proposed schemes was done on an interactive real-time MR-scanner. Cardiac function studies clearly showed the potential of this technique for PR- and spiral imaging.