Research vessels at the centre of the lesion

Epub: Gaitán et al. Initial investigation of the blood-brain barrier in MS lesions at 7 tesla. Mult Scler. 2012 Dec 17.

BACKGROUND: We previously described two dynamics of contrast enhancement in scans of active multiple sclerosis lesions: Medium-sized, early lesions enhance centrifugally, whereas larger, slightly older lesions enhance centripetally. Due to technical limitations, our previous study did not characterize lesions < 5 mm in diameter, cortical enhancement, and anatomical structures within lesions.

OBJECTIVE: The objective of this paper is to obtain initial observations of these important aspects of lesion development on a 7 tesla scanner at high spatial resolution. 

METHODS: We scanned eight patients, acquiring precontrast T2*-weighted scans, T1-weighted scans before and after contrast, and high-resolution dynamic contrast-enhanced scans during and up to 30 min after contrast. 

RESULTS: We detected 15 enhancing lesions, obtaining dynamic data in 10: Five lesions < 4 mm enhanced centrifugally (initial central enhancement expanded outward), and five lesions > 4 mm enhanced centripetally (initial peripheral enhancement gradually filled the lesion). A leukocortical lesion (lesion spanning the grey and white matter) initially showed enhancement in its white matter portion, which gradually spread into the cortex. Seventy-three percent of lesions were clearly perivenular.

CONCLUSION: Most active lesions are perivenular, and the smallest lesions enhance centrifugally. This supports the idea that lesions grow outward from a central vein.



Well more data indicating that the lesions expand from around vessels. This is consistent with the histology, but it does not necessaily say what the trigger is and may not centre on the vasculature but may be just outside this. The MRI does not have the resolution for this 4mm could be 40-400 cells thick  and we know that gadolium (the tracer) is entering the brain from the vasculature but as it expands from it does point to a central role in lesion formation.

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