FIG. 4.

Calibration curves for concentration-dependent LW broadening. (A) Relationship between the concentration (spin density) of Oxo63 and the extrapolated signal intensity at τ = 0 ns. (B) Relationship between the concentration of Oxo63 and LW at 0 mmHg. Each symbol indicates an independent measurement. Circles indicate 0.25, 0.5, 1.0, and 1.5 mM Oxo63 solutions. Triangles indicate 0.5, 1.0, 1.5, and 2.0 mM solutions. Squares indicate 1.0, 1.5, 2.0, and 3.0 mM solutions. Diamonds indicate 5, 10, 15, and 20 mM solutions. Data points >3 mM (marked with open circles) in (B) were used to observe a linear equation. Inset shows the relationship in an expanded scale of 0–5 mM. Relationship between pO₂ and the oxygen-dependent LW broadenings. (C) LW mapping of a phantom containing 3 mM Oxo63 solutions with different oxygen levels. (D) Oxygen-dependent LW broadening was obtained after the correction of concentration broadening. Values are plotted as average ± SD of 374 pixels. Image acquisition time for a matrix of 31 × 31 size in three gradient ranges was 264 s. Adapted from Ref. (38) with permission. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars