Magnetic resonance frequency shifts during acute MS lesion formation

Background and Purpose To quantify iron related myelin damage in chronic multiple sclerosis lesions with hyperintense susceptibility rim consistent with iron deposition compared to those without rim. Methods Forty-six patients had two longitudinal quantitative susceptibility mapping (QSM) with automatic zero reference (QSM0) scans with a mean interval of 28.9 ± 11.4 months. Myelin water fraction (MWF) mapping using fast acquisition with spiral trajectory and T2prep (FAST-T2) was obtained at the second time point to measure myelin damage. Mixed-effects models were utilized to assess lesion QSM and MWF values. Results QSM were on average 6.8 ppb higher in 116 rim+ lesions compared to 441 rim− lesions, p<0.0001. All rim+ lesions retained hyperintense rim over time, with increasing QSM values of both rim and core regions, p<0.0001. QSM and MWF in rim+ lesions decreased from rim to core, which is consistent with rim iron deposition. Whole lesion MWF for rim+ and rim− lesions was 0.055 ± 0.07 and 0.066 ± 0.04, respectively. In the mixed-effects model, rim+ lesions had on average 0.01 lower MWF as compared to rim−, p<0.0001. The volume of the rim at initial QSM was negatively associated with follow-up MWF, p=0.0015. Conclusion QSM rim+ lesions maintained a hyperintense rim, increased in susceptibility and had more myelin damage compared to rim− lesions. Our results are consistent with identification of chronic active MS lesions and may provide a target for therapeutic interventions to reduce myelin damage.

Section: Discussionsupporting

confidence: 60%

Combining Quantitative Susceptibility Mapping with Automatic Zero Reference (QSM0) and Myelin Water Fraction Imaging to Quantify Iron-Related Myelin Damage in Chronic Active MS Lesions

Yao

Nguyen²,

Pandya³

et al. 2017

“…By omitting the acquisition of the sagittal 2D-FLAIR, the 2D proton density-weighted image, and potentially the DIR, approximately 20 minutes of acquisition time is saved, which can be invested in acquiring 3D sequences at higher spatial resolution, for instance. In research studies, the remaining scanning time can also be used in the acquisition of advanced MR images, such as myelin water, 26 magnetization transfer imaging, 27 or susceptibility-weighted imaging [28][29][30] for the calculation of frequency maps as measures of MS tissue damage 31 and of R2* maps.…”

Section: Considerations For Data Acquisitionmentioning

confidence: 99%

FLAIR²: A Combination of FLAIR and T2 for Improved MS Lesion Detection

Wiggermann¹,

Hernández‐Torres²,

Traboulsee

et al. 2015

Self Cite

BACKGROUND AND PURPOSE: FLAIR and double inversion recovery are important MR imaging scans for MS. The suppression of signal from CSF in FLAIR and the additional suppression of WM signal in double inversion recovery improve contrast between lesions, WM and GM, albeit at a reduced SNR. However, whether the acquisition of double inversion recovery is necessary is still debated. Here, we present an approach that allows obtaining CSF-suppressed images with improved contrast between lesions, WM and GM without strongly penalizing SNR.

“…Previous studies have reported changes in acute MS lesions regarding MR imaging frequency shift, 10 magnetization transfer ratio, 11 and relaxation values, 12 suggesting the possibility of using quantitative methods to distinguish and characterize the acute lesions. However, so far no method has met the requirements necessary to be considered fully clinically applicable.…”

mentioning

confidence: 99%

Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent

Blystad¹,

Håkansson²,

Tisell³

et al. 2015

BACKGROUND AND PURPOSE:Contrast-enhancing MS lesions are important markers of active inflammation in the diagnostic work-up of MS and in disease monitoring with MR imaging. Because intravenous contrast agents involve an expense and a potential risk of adverse events, it would be desirable to identify active lesions without using a contrast agent. The purpose of this study was to evaluate whether pre-contrast injection tissue-relaxation rates and proton density of MS lesions, by using a new quantitative MR imaging sequence, can identify active lesions.