Radiolabeled neutrophils in COPD. (A) SPECT/CT
images (coronal,
sagittal, and transverse views, respectively) from (i) a saline-challenged
healthy volunteer, (ii) an LPS-challenged healthy volunteer, and (iii)
a patient with COPD. The large airspaces, with negligible radioactivity,
are black and can be seen in the emphysematous lung (iii). (B) Composite
Patlak–Rutland graphical plot in saline-challenged healthy
volunteers, LPS-challenged healthy volunteers and patients with COPD.
The plot gradient represents blood clearance of 99mTc-neutrophils
to the lungs in mL/min/mL lung volume. The y-axis
intercept corresponds to the 99mTc-neutrophil distribution
volume. The profiles for COPD patients and LPS-treated subjects are
similar to each other and markedly different from saline-treated healthy
subjects. Adapted with permission from Tregay et al., ref (318). Copyright Tregay et
al. 2019. Published by BMJ under CC license [https://creativecommons.org/licenses/by/4.0/].