Fig. 2.

(A) Axial PA image in a representative mouse showing 800-nm background (grayscale) with HbO₂ (red) and HHb (blue) unmixed overlay with signal from femoral BM (indicated by teal circles); (B) matched X-ray CT to show anatomy. (C) Overlay of X-ray CT on PA image shows that the hemoglobin signal seen in the PA image co-locates with the BM cavity seen on X-ray CT, indicating that the signal originated in the BM. Femoral arteries are indicated by red circles. (D) SNR-masked SO₂ image overlaid on 800-nm PA image demonstrates that sufficient SNR is achieved in the BM cavity to reliably estimate femoral SO₂.