This study from Italy investigated the potential of ultrahigh-field MRI (7 tesla), in particular phase imaging combined with dynamic contrast enhancement, to provide a better insight into acute MS lesions.
The study included 16 active MS patients. Non-contrast, high-resolution T2* magnitude and phase scans, T1 scans pre- and post-gadolinium and dynamic contrast-enhanced (DCE) T1 scans were acquired, with one year follow-ups performed. They found that centrifugal DCE lesions appeared isointense/hypointense on phase images, while centripedal DCE lesions showed thin, hypointense phase rims that clearly colocalised with the initial site of contrast enhancement. This appearance tended to disappear once enhancement resolved.
In contrast, chronic lesions were stable over time and the hypointense phase rims were typically thicker and darker. This raises the possibility of different underlying pathological processes in the two lesion types. Overall, the ultrahigh-field MRI is very sensitive to tissue changes in acute MS lesions, which have different patterns from those seen on chronic lesions. The hypointense phase rim may represent the expanding inflammatory edge and may correspond to inflammatory byproducts.
Authors: Absinta M, Sati P
Source: Ann Neurol. 2013 Jun 28. doi: 10.1002/ana.23959. [Epub ahead of print]
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