Characterization of hematopoietic bone marrow in male professional cyclists by magnetic resonance imaging of the lumbar spine

Abstract

Purpose To prospectively evaluate hematopoietic bone marrow of male professional cyclists in relation to performance data and laboratory data, and in comparison to age‐matched healthy volunteers. Materials and Methods Twenty male cyclists and 44 volunteers (27 males and 17 females) were prospectively studied by magnetic resonance imaging (MRI) at high‐field strength. A sagittal T1‐weighted (T1‐w) spin‐echo (SE) sequence, a gradient‐echo (GE) sequence with an echo time (TE) for out‐of‐phase (OOP) imaging, and a turbo inversion‐recovery sequence with short inversion time (TIRM) for fat suppression was used. The averaged bone marrow signal intensity (SI) of three adjacent vertebrae was related to the signal of an adjacent nondegenerative disk. Results The cyclists revealed a significantly different SI as compared to male volunteers in the OOP (0.34 ± 0.14 vs. 0.28 ± 0.09, P < 0.05) and T1‐w sequences (1.62 ± 0.19 vs. 1.77 ± 0.30, P < 0.05). Only in TIRM was there a significant difference compared to female volunteers (0.36 ± 0.08 vs. 0.44 ± 0.04, P < 0.01). MRI data of cyclists did not correlate to hemoglobin, erythrocyte, or reticulocyte counts; ferritin, relative heart volume, relative maximal power (rPmax; W/kg bw), or relative maximal oxygen consumption (VO₂max). A borderline linear correlation was found for hematocrit (OOP: r = 0.42, P = 0.06; TIRM: r = 0.44, P = 0.06). Conclusion Bone marrow hyperplasia is observed in male professional cyclists in the axial skeleton. The MR findings are probably independent of mechanically induced marrow edema. A multifactorial cause must be considered, as single laboratory and performance data did not appear to contribute significantly to these results. J. Magn. Reson. Imaging 2002;16:284–288.