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Periarticular bone findings in rheumatoid arthritis: T2-weighted versus contrast-enhanced T1-weighted MRI.

OBJECTIVE
The purpose of this study was to establish the relative predictive value of T2-weighted and contrast-enhanced T1-weighted MRI techniques for bone erosions that are evident on CT. Because it is known that MRI depicts abnormalities in the periarticular bone of patients with rheumatoid arthritis, we wanted to compare the outcomes of T2-weighted versus contrast-enhanced T1-weighted MRI techniques.


MATERIALS AND METHODS
Eleven patients with rheumatoid arthritis underwent CT imaging of their most affected wrist. Fast spin-echo T2-weighted MR images were then acquired with spectral fat saturation. Enhanced T1-weighted spin-echo images acquired before and after IV administration of gadopentetate dimeglumine were used to determine the percent enhancement. Imaging examinations were scored for 15 anatomic zones. The CT score was based on cortical bone erosion. The MR score was based on periarticular bone marrow signal alteration.


RESULTS
Both T2-weighted MR images with spectral fat saturation and enhanced T1-weighted images were concordant for the presence or absence of bone abnormalities in 122 of 165 zones (74%). Of the 43 zones that were discordant for an abnormality by the two MR techniques, the T2-weighted images were positive in five zones, and enhanced T1-weighted images were positive in 38 zones (p < 0.001). Of the 43 zones that were discordant by the two MR techniques, enhanced T1-weighted images were concordant with CT in 20 zones, whereas the T2-weighted images were concordant with CT in 23 zones (p = 0.76). A greater proportion of lesions detected by the T2-weighted images were "edema-like" signal patterns.


CONCLUSION
In rheumatoid arthritis, contrast-enhanced T1-weighted MRI depicts more periarticular bone abnormalities than fat-suppressed T2-weighted MRI. These MR techniques are equally predictive of frank, erosive disease that is evident on CT.