Friday, 20 March 2015

Testing your metal - imaging veins in MS lesions

Characterization of Multiple Sclerosis Plaques Using Susceptibility-Weighted Imaging at 1.5 T: Can Perivenular Localization Improve Specificity of Imaging Criteria?

Lane JI, Bolster B, Campeau NG, Welker KM, Gilbertson JR. J Comput Assist Tomogr 2015 Mar 17. [Epub ahead of print]
BACKGROUND AND PURPOSE:The purpose of this study was to determine if magnetic resonance (MR) susceptibility-weighted imaging (SWI) can increase the conspicuity of corticomedullary veins within the white matter lesions of multiple sclerosis (MS) and, thus, aid in distinguishing plaques from leukoaraiosis.
METHODS: We retrospectively reviewed MR examinations in 21 patients with a clinical diagnosis of MS and 18 patients with a clinical diagnosis of dementia. Examinations included fluid-attenuated inversion recovery (FLAIR) and SWI sequences obtained in the axial plane. Lesions greater than 5 mm in diameter on the axial FLAIR sequence were identified as periventricular or subcortical. Three neuroradiologists evaluated SWI images, compared with FLAIR, for a centrally located signal void in each lesion that was scored as present, absent, or indeterminate.
RESULTS:In patients with MS, central veins were present in both periventricular lesions (75%, P < 0.001) and subcortical lesions (52%, P < 0.005). In patients with dementia, central veins were seen much less frequently in subcortical lesions (14%, P < 0.001); their association with periventricular lesions was not significant.
CONCLUSION: Central veins were detected in MS lesions with a significantly greater frequency than that in patients with dementia. Susceptibility-weighted imaging increases the conspicuity of corticomedullary veins and may improve the specificity of MR findings in MS.


MRI is regularly being used in the diagnostic work-up when MS is suspected, however the current revised "McDonald" criteria, which rely on the size, shape and distribution pattern ("dissemination in time and space") of lesions in the brain and spinal cord are not entirely fool proof.  A recent approach to make MRI more specific to support (or rule out) a diagnosis of MS is based on a histological hallmark of MS lesions: the central vein around which most lesions - certainly in the brain white matter - evolve. This feature, the "central vein sign" (CVS) can be visualised using MRI techniques that are particularly sensitive ("susceptible") to the iron in haemoglobin in veins. There are several variations on the theme, sometimes combining "lesion scans" (such as T2 or FLAIR) with "iron" scans (for example T2*) to refine the detection of CVS as a new diagnostic tool such as in the example below by Pascal Sati and colleagues in Danny Reich's group at the NIH/NINDS:
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Those attending the BartsMS/UCLP Research Day tomorrow will learn what our team is currently doing to develop the non-invasive histological diagnosis of MS further.

4 comments:

  1. So what's the big idea ?

    Regards as always.

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    Replies
    1. The first idea is to be quicker and more accurate in diagnosis. However, looking for veins in lesions may also be of value in people with MS who have a co-morbidity such as high blood pressure. High blood pressure can lead to lesions in the brain, a condition called cerebral small vessel disease (CSVD). These lesions can look identical to MS lesions on standard MRI. In situations where disease activity needs to be assessed using MRI it would be very useful to be confident new lesion(s) are due to MS rather than CSVD.

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  2. You mentioned veins so CCSVI must be true....ha ha.

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  3. I didn't even remotely think of that, but I appreciate your "ha ha", so thanks for the joke:-)

    ReplyDelete

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