Fig. 10.
Simulation comparison between SE, STE and super-STE diffusion sequences, assuming a typical clinical system maximum gradient strength of 4 G/cm, neglecting gradient ramps, and a single-exponential model for the super-STE (Eq. 26). (A) For hyperpolarized 13C-pyruvate imaging with estimated in vivo relaxation rates. The dashed gray lines indicate the approximate b-value threshold where a super-STE approach is advantageous over a SE. The colored dashed lines demonstrate key tradeoffs: (left) The STE and super-STE have less signal as T1 is shortened due to mixing time relaxation. (right) Increased RF pulse dead-time reduces signal for all sequences, and the loss is greater in the super-STE due to a larger number of pulses used. (B) 1H diffusion for several tissue types with Tdead = 2 ms. For skeletal muscle and cartilage, which have shorter T2s, the super-STE is advantageous for large b-values.