[Magnetic resonance imaging in the warm and cold forms of algodystrophy of the foot].
PURPOSE: To report magnetic resonance imaging abnormalities in reflex sympathetic dystrophy of the foot. METHODS: Retrospective study of 22 algodystrophies of the foot, in warm phase in 17 cases, in cold phase in 5. RESULTS: Algodystrophy in warm phase: Bone medullary abnormalities were noted in 17 cases (decrease of signal intensity was found in T1 weighted images, increase of signal intensity in T2 weighted images, in T1 and T2 with fat-saturation, in T1 with gadolinium), located at the increased uptake technetium site in 16 cases. T1 and T2 weighted images with fat-saturation and T1 with fat-saturation after injection of gadolinium were pathological in all cases, T1 was normal in 2 cases. Soft tissues abnormalities were noted in 11 cases, joint effusion in 8 cases, synovial hypertrophy enhanced by gadolinium in 2 cases and a subchondral linear area of hypointense signal on T1 and T2 images was not present after gadolinium injection in 1 case. Six fractures were detected. Algodystrophy in cold phase: no bone edema, no synovial hypertrophy, no joint effusion, no soft tissues abnormalities, no fractures are detected. CONCLUSION: The results suggest that the MRI has a considerable value in diagnosis during the warm phase of reflex sympatetic dystrophy of the foot. The normal MRI findings during the cold phase could be important to understand its etiology.