Dynamic contrast-enhanced MR imaging in symptomatic bone stress of the pelvis and the lower extremity

Purpose: To assess the value of dynamic contrast-enhanced MR imaging in bone stress of the pelvis and the lower extremity.Material and Methods: Thirty patients (37 reactions; aged 17-25 years, mean 20.5 years) with MR findings of 37 bone stress reactions were examined using dynamic gadolinium contrast enhancement. The enhancement was evaluated with time-intensity curves. The highest slope and maximum enhancement values were calculated and compared with the different precontrast MR imaging signs of bone stress reactions.Results: There was a significant difference in the highest slope values between the site of the bone stress reaction and the reference points. In 24 of the 37 reactions the dynamic contrast enhancement was regarded as positive. A fracture line, callus, and muscle edema were the MR imaging signs which had a significant correlation to the dynamic contrast enhancement. Neither periosteal nor marrow changes showed any significant correlation. A new MR grading system for bone stress reactions could be assessed.Conclusion: Increased tissue perfusion could be seen if precontrast MR imaging revealed callus, fracture line or muscle edema surrounding the bone stress reaction.