Dynamic contrast-enhanced MR imaging of the water fraction of normal bone marrow and diffuse bone marrow disease.

PURPOSE

To clarify the contrast-enhancement pattern of the normal hematopoietic element by isolating the signal of the water fraction in vertebral bone marrow and to investigate whether this approach can be used to characterize bone marrow pathology in several diffuse bone marrow diseases.

METHODS

Two groups were examined: 30 normal healthy volunteers and 19 patients with primary diffuse bone marrow disease (aplastic anemia [n=8], myelodysplastic syndrome (MDS) [n=5], chronic myelogenic leukemia (CML) [n=4], polycythemia vera [n=2]). Isolation of the signal of hematopoietic tissue was done by the chemical-shift misregistration effect. Twenty consecutive T1-weighted midsagittal lumbar vertebral images were obtained immediately after the intravenous administration of Gd-DTPA of 0.1 mmol/kg body weight, and the pattern of the time-intensity curve, the peak contrast-enhancement (CE) ratio, and the washout rate (%/min) of bone marrow in normal volunteers were compared with those in patients suffering from primary diffuse bone marrow disease.

RESULTS

The pattern of the time-intensity curve of patients with aplastic anemia showed a low peak value followed by a slow washout. However, the pattern of time-intensity curves in patients with MDS, CML, and polycythemia vera was similar to that of normal volunteers. The peak CE ratio of the water fraction in normal marrow ranged from 0.45 to 1.26 (mean +/- S.D.: 0.87 +/- 0.18). Patients with aplastic anemia showed an abnormally lower peak CE ratio of the water fraction (mean +/- S.D.: 0.34 +/- 0.19, p<0.0001). On the other hand, the peak CE ratio of the water fraction in patients with MDS was significantly higher than that of normal volunteers (mean +/- S.D. 1.35 +/- 0.39, p<0.05). In contrast, the peak CE ratio of patients with CML or polycythemia vera did not differ significantly from that of normal volunteers. The mean washout rate of patients with aplastic anemia was significantly lower than that of normal volunteers (mean +/- S.D.: 3.50 +/- 2.51%/min vs. 7.13 +/- 1.74%/min, p<0.01). However, there was no significant difference in the washout rate among patients with MDS, CML, polycythemia vera, and normal volunteers.

CONCLUSION

Dynamic contrast-enhanced MR imaging of the water fraction provides additional valuable qualitative information about structural changes of the hematopoietic element.