T2 measurement of the human myocardium using a T2-prepared transient-state TrueFISP sequence.
A fast and motion-insensitive technique suitable for myocardial BOLD contrast imaging is presented. The method, termed T2-TrueFISP, combines T2 magnetization preparation with steady-state free precession (SSFP) imaging for T2 relaxation mapping of the myocardium in healthy volunteers. The T2 contrast-to-noise ratio (CNR) was optimized with the use of transient-state TrueFISP readout and half-Fourier readout with linear phase encoding. Single-slice myocardial T2-weighted image was obtained within one heartbeat, and a single slice T2 map of the myocardium was obtained in under 5-7 s. A respiratory navigator-gating method was incorporated for serial measurements and signal averaging, with the subjects breathing freely. The mean myocardial T2 relaxation time measured in 12 healthy volunteers was 54 +/- 5.7 ms. Regional variations of T2 values across the myocardium were 7%. Temporal variations across serial T2 measurements in a transmural region covering approximately 0.5 cc of the left ventricular (LV) wall were 3.6% without signal averaging (number of excitations (NEX) = 1) and 1.7% with signal averaging (NEX = 10). According to our preliminary results, the T2-TrueFISP method is expected to provide a robust and sensitive tool for clinical application of myocardial BOLD contrast imaging.
Huang
Teng-Yi
TY
Massachusetts General Hospital, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA. tyhuang@mail.ntust.edu.tw
Liu
Yi-Jui
YJ
Stemmer
Alto
A
Poncelet
Brigitte P
BP
D000328:Adult; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009206:Myocardium; D019047:Phantoms, Imaging