Figure 2:

Timing diagram of the “dual-band-Kidney Metabolism of Oxygen via T₂ and Interleaved Velocity Encoding” (db-K-MOTIVE) pulse sequence. db-K-MOTIVE builds on the K-MOTIVE sequence and measures T₂ and blood flow velocity at two locations simultaneously (i.e., a total of four parameters). T₂ is converted to venous oxygenation (SvO₂) by calibration model. Following an initial global saturation, an ungated dual-band golden-angle radial phase-contrast module is applied (A) with a zero and nonzero first moment to achieve flow compensation and velocity-encoding, respectively. Dual-band RF-pulse was designed as a combination of two single-band RF-pulses, where the polarity of the second (β) pulse alternates throughout the acquisition (“n” represents pulse index). Dual-band background suppression (B) consists of selective and non-selective adiabatic inversion pulses. The selective adiabatic inversion pulses are in turn a summation of two single-band slice-selective adiabatic inversion pulses that are partially shifted in time to minimize peak RF power. T₂-preparation is based on Malcolm-Levitt (MLEV-4) pattern (C). Lastly, a dual-band bSSFP module sampled the magnetization with a partial-Fourier Cartesian readout (D). In this module, the dual-band RF-pulse also comprises two single-band RF-pulses. However, the phase increments of the (α) and (β) pulses are +π/2 and –π/2, respectively, to shift one slice by half of the FOV. The entire scheme is then repeated N times (N = number of TEs) to result in additional velocity-encoded spokes and T₂-weighted images. With an inter-refocusing pulse time (τ₁₈₀) of 12ms, each additional interleaf extends the MLEV preparation by another four composite pulses to increase the effective TE by 4*τ₁₈₀ ms. In the present study, five TEs were included corresponding to a pulse sequence duration of 21 seconds. Figure is not to scale.