Inversion recovery with embedded self-calibration (IRES).
With self-calibrated parallel acquisition, the calibration data used to characterize coil response are acquired within the actual, parallel scan. Although this eliminates the need for a separate calibration scan, it reduces the net acceleration factor of the parallel scan. Furthermore, this reduction gets worse at higher accelerations. A method is described for three-dimensional inversion recovery gradient-echo imaging in which calibration is incorporated into the sequence but with no loss of net acceleration. This is done by acquiring the calibration data using very small (<or=4 degrees) tip angle acquisitions during the delay interval after acquisition of the accelerated imaging data. The technique is studied at 3 Tesla with simulation, phantom, and in vivo experiments using both image-space-based and k-space-based parallel reconstruction methods. At nominal acceleration factors of 3 and 4, the newly described inversion recovery with embedded self-calibration (IRES) method can retain effective acceleration with comparable SNR and contrast to standard self-calibration. At a net two-dimensional acceleration factor of 4, IRES can achieve higher SNR than standard self-calibration having a nominal acceleration factor of 6 but the same acquisition time.
MR Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA.
Ek T
ET
Tan
Stephen J
SJ
Riederer
D000328:Adult; D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D002138:Calibration; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods / Q000592:standards; D007090:Image Interpretation, Computer-Assisted / Q000379:methods* / Q000592:standards*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States