Estimation of bone marrow cellularity using digital image nucleated cell counts in patients receiving chemotherapy

Introduction: Bone marrow cellularity under microscopic examination has a wide range of variation. The number of nucleated cells in a certain volume of bone marrow could represent more accurate cellularity. In this study, we compared the cellularity under the microscope with the nucleated cell counts on the biopsy sections to assess the usefulness of nucleated cell count as a representative cellularity marker. Methods: Three hundred and twenty-five bone marrow biopsies were analyzed. Two pathologists determined bone marrow cellularity using digital images with ×100 magnification from biopsy sections. Nucleated cell counts on the digital images with ×100 magnification were determined using automated cell counting software. Results: A wide range of variation was observed in the nucleated cell counts among the biopsies with the same cellularity. A good correlation was observed between the cellularity under the microscope (×100 magnification) and the nucleated cell counts (r = 0.816, P < 0.05). The nucleated cell counts, using the automated cell counting software, had no significant interobserver difference (F = 0.001, P = 0.972). The intraclass correlation coefficient (ICC) of the nucleated cell count between two observers was 0.952. Conclusion: The nucleated cell counts in the bone marrow biopsy could represent the number of residual hematopoietic cells more accurately than the method of cellularity under the microscope. The nucleated cell counts in the bone marrow biopsy could be especially helpful to determine cellularity after initial chemotherapy.