A Novel 4D EP-COSI Sequence Development Research Featured on the Cover of Magnetic Resonance in Medicine
11/01/2010
Dr. Albert Thomas and his colleagues' paper,
"Echo planar correlated spectroscopic imaging: Implementation and pilot evaluation in human calf in vivo", has been selected as the cover feature article for the 2010 October issue of
Magnetic Resonance in Medicine.
Abstract
Exploiting the speed benefits of echo-planar imaging (EPI), the echo-planar spectroscopic imaging (EPSI) sequence facilitates recording of one spectral and two to three spatial dimensions faster than the conventional magnetic resonance spectroscopic imaging (MRSI). A novel four dimensional (4D) echo-planar correlated spectroscopic imaging (EP-COSI) was implemented on a whole body 3 T MRI scanner combining two spectral with two spatial encodings. Similar to EPSI, the EP-COSI sequence used a bipolar spatial read-out train facilitating simultaneous spatial and spectral encoding, and the conventional phase and spectral encodings for the other spatial and indirect spectral dimensions, respectively. Multiple 2D correlated spectroscopy (COSY) spectra were recorded over the spatially resolved volume of interest (VOI) localized by a train of three slice-selective radiofrequency (RF) pulses (90°-180°-90°). After the initial optimization using phantom solutions, the EP-COSI data were recorded from the lower leg of eight healthy volunteers including one endurance trained volunteer. Pilot results showed acceptable spatial and spectral quality achievable using the EP-COSI sequence. There was a detectable separation of cross peaks arising from the skeletal muscle intramyocellular lipids (IMCLs) and extramyocellular lipids (EMCLs) saturated and unsaturated pools. Residual dipolar interaction between the N-methylene and N-methyl protons of creatine/phosphocreatine (Cr/PCr) was also observed in the tibialis anterior region.
Dr. Thomas' co-authors are Dr. Scott Lipnick (currently a fellow at NIH). Mr. Gaurav Verma of UCLA Geffen School of Medicine, Dr. Saadallah Ramadan of Brigham and Women's Hospital & Harvard Medical School, and Dr. Jon Furuyama of UCLA Geffen School of Medicine. Dr. Saad Ramadan had worked as a paid consultant for one month at UCLA during the earlier phase of this project. The entire work was funded by NIH R01 and US Army IDEA grants.
