Accuracy and Precision in Quantitative Rotating Frame Relaxometry at High and Ultra-High Magnetic Fields

Purpose: This work is based on the review of novel MRI methods for generating the longitudinal relaxation contrast, T1ρ, and the transverse relaxation contrast, T2ρ in the rotating reference frame regime at high and ultra-high magnetic fields. Clinical application of the T1ρ and T2ρ contrasts using the onor off-resonance spin-lock (SL) radiofrequency (RF) irradiation has been a challenging task. Long acquisition time and high RF energy deposition into the tissue (specific absorption rate i.e., SAR) in the SL based methods are the major problems. SL RF pulse cluster and adiabatic RF pulses based MRI acquisition schemes for accurate and precise quantitative estimation of T1ρ and T2ρ have been reviewed in detail in this work.