Bone marrow MR imaging findings in disuse osteoporosis.

OBJECTIVE

To demonstrate MR imaging findings in the cortical and trabecular bone as well as marrow changes in patients with disuse osteoporosis (DO).

MATERIALS AND METHODS

Sixteen patients (14 men, 2 women, aged 27-86 years) with clinical and radiographic evidence of DO of a lower limb joint (10 knees, 6 ankles) with MR examination of the same joint performed within a 1-month period were selected, as well as 16 healthy volunteers (7 men, 9 women, aged 25-75 years, 10 knees and 6 ankles). MR imaging findings of the bone marrow were analyzed by 2 musculoskeletal radiologists in consensus regarding: diffuse or focal signal alteration, reinforcement of vertical or longitudinal trabecular lines, and presence of abnormal vascularization.

RESULTS

All patients (100%,16/16) with DO presented MR imaging abnormalities of the bone marrow, such as: accentuation of vertical trabecular lines (50%, 8/16), presence of subchondral lobules of fat (37.5%, 6/16), presence of horizontal trabecular lines (31%, 5/16), prominence of bone vessels (25%, 4/16), and presence of dotted areas of high signal intensity on T2-weighted fat-suppressed sequences (12.5%, 2/16). Such MR findings did not appear in the control individuals.

CONCLUSION

There are several MR imaging findings in bones with DO that range from accentuation of vertical and horizontal marrow lines, presence of subchondral lobules of fat, prominent bone vascularization and the presence of dotted foci of high signal intensity on T2-weighted fat-suppressed sequences. Recognition of these signs may prove helpful in the identification of DO as well as distinguishing these findings from other entities.