Figure 3.

Four images from unstained bone marrow biopsies obtained from patients with myeloproliferative neoplasms with a spectrum of marrow fibrosis ranging from 0–3 according to the revised European consensus system for grading bone marrow fibrosis. The red is a pseudo color that highlights all tissue elements in the bone marrow according to two-photon excitation. The technology utilizes the second harmonic generation phenomenon to highlight fibrillar collagen with high specificity as highlighted by the green fluorescent colored structures.