Jing-Tzyh Alan Chiang1, Michael Carl2, Mark Bydder1, Jiang Du1, Robert F. Mattrey1, Graeme Bydder1
1Radiology, University of California San Diego, San Diego, CA, USA; 2Applied Science Laboratory, GE Health Care
MR imaging of tissues with submillisecond T2s is possible with UTE (ultrashort TE) sequences that utilize half RF excitation pulses and radial projection readouts. For UTE sequences, TE is customarily defined to be from the end of the half RF pulse to the beginning of radial projection readout. We present data here that show phase accrual in UTE imaging to be more than expected for this customary definition of TE. Numerical calculations show this is largely due to phase accrual before the end of the RF pulse, and we suggest an alternate definition of TE for phase calculations in UTE.