MAGNETIC-RESONANCE-IMAGING OF VERTEBRAL B ONE-MARROW - A DENSITOMETRIC ANALYSIS

BACKGROUND: Images obtained by magnetic resonance can present changes in a variety of haematologic disorders, The vertebral magnetic resonan ce signal depends chiefly on the relationship between fatty and cellul ar components of the haemopoietic bone marrow. A quantitative analysis of signal can be performed either during the magnetic resonance exami nation or on the computer-stored images. In this work, a densitometric grey-scale method is presented allowing to analyze the signal intensi ty on printed magnetic resonance images for those cases in which the c omputer-stored information is lacking. PATIENTS AND METHODS: A compara tive study between magnetic resonance signal and the result of the den sitometric analysis was carried out in 29 patients with different haem atologic disorders. In order to achieve a suitable standardization, an internal control in both measures was used, i.e., the magnetic resona nce signal intensity and the grey intensity of an area of spinal cord, respectively, yielding two ratios: magnetic resonance ratio and grey ratio. RESULTS: The precision analysis of the densitometric method gav e the following results: within-batch coefficient of variation was 1.7 8%, between-batch coefficient of variation was 1.94% and overall repro ducibility 6.4%. The correlation between magnetic resonance ratio and grey ratio was very high, i.e., 0.98 (p < 0.001). Moreover, the regres sion line displayed an ideal location since it originated in the point 0 and showed a slope of 45 degrees. CONCLUSION: The densitometric met hod presented in this paper can be useful for the quantitative analysi s of the magnetic resonance signal intensity generated by the haemopoi etic bone marrow, for those cases in which the computer-stored informa tion is lacking.