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

Background and Purpose Magnetic susceptibility values of multiple sclerosis (MS) lesions increase as they change from gadolinium (Gd) enhancing to non-enhancing. Can susceptibility values measured on quantitative susceptibility mapping (QSM) without Gd injection be used to identify the status of lesion enhancement in surveillance MRI used to monitor MS patients? Materials and Methods In patients who had a prior MRI and are having QSM in a current MRI, new T2-weighted lesions were evaluated for enhancement on a conventional T1-weighted with Gd, and their susceptibility values were measured on QSM. Receiver-operating-characteristics (ROC) analysis was used to assess the diagnostic accuracy of using QSM in distinguishing new Gd enhancing from new non-enhancing lesions. A generalized estimated equation was used to assess difference in susceptibility values between lesion types. Results In 54 patients, we identified 86 out of 133 new lesions that were Gd enhancing and had relative susceptibility values significantly lower than those of non-enhancing lesions (β=−17.17(−20.2 to −14.2), p <.0001). Using susceptibility values to discriminate enhancing from non-enhancing lesions, we performed receiver operating characteristic (ROC) analysis and found that the area-under-the-curve (AUC) was 0.95 (0.92 to 0.99). Sensitivity was measured at 88.4% and specificity at 91.5% with a cutoff-value of 11.2 ppb for QSM-measured susceptibility. Conclusion During routine MRI monitoring to detect new MS lesion activity, QSM can be used without gadolinium injection for accurate identification of the BBB leakage status in new T2w lesions.

Section: Discussionmentioning

confidence: 99%

Magnetic Susceptibility from Quantitative Susceptibility Mapping Can Differentiate New Enhancing from Nonenhancing Multiple Sclerosis Lesions without Gadolinium Injection

Zhang

Gauthier

Gupta

et al. 2016

“…For example, the data in Fig.6 suggest that 1) T2w lesions with relative susceptibility value near zero may be nodular enhancing, opening another venue for the current exploration of identifying enhancing lesions without gadolinium injection 33–35 , and 2) simultaneous QSM and R2* increase indicates iron accumulation in MS lesion, offering an in vivo tool to study iron-related inflammation behind a sealed BBB that cannot be demonstrated with conventional imaging.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Susceptibility Mapping and R2* Measured Changes during White Matter Lesion Development in Multiple Sclerosis: Myelin Breakdown, Myelin Debris Degradation and Removal, and Iron Accumulation

Zhang

Gauthier²,

Gupta³

et al. 2016

Background and Purpose QSM and R2* are sensitive to myelin and iron changes in MS lesions. This study was designed to characterize lesion changes on QSM and R2* at various gadolinium-enhancement stages. Materials and Methods 64 MS patients were included with different enhancing patterns in white matter lesions: nodular, shell-like, non-enhancing < 1 year old and non-enhancing 1–3 years old, representing acute, late acute, early chronic and late chronic lesions respectively. Susceptibility values measured on QSM and R2* values were compared among the four lesion types. Their differences were assessed with a generalized estimating equation, controlling for EDSS, age and disease duration. Results 203 lesions were analyzed: 80 were nodular-enhancing, of which 77 (96.2%) were QSM isointense; 33 were shell-enhancing, of which 30 (90.9%) were QSM hyperintense; 49 were non-enhancing lesions < 1 year old and 41 were non-enhancing lesions 1–3 years old, all were QSM hyperintense. Their relative susceptibility/R2* values were 0.50 ± 4.44 ppb/−5.59 ± 2.92 Hz, 10.21 ± 5.45 ppb/−7.99 ± 2.63, 20.21 ± 7.81 ppb /−3.06 ± 2.34 Hz and 33.22 ± 8.16 ppb/−2.00 ± 2.59 Hz, respectively, and were significantly different (p <.005). Conclusions Early active MS lesions with nodular enhancement show R2* decrease but no QSM change, reflecting myelin breakdown; late active lesions with peripheral enhancement show R2* decrease and QSM increase in the lesion center, reflecting further degradation and removal of myelin debris; early or late chronic non-enhancing lesions show both QSM and R2* increase, reflecting iron accumulation.

“…Given that blood-brain barrier disruption and edema formation are correlated phenomena, 28 a higher V EPW may suggest the existence of blood-brain barrier disruption. Although R1, R2, and PD are good predictors of lesion enhancement, 29 the combination of V MY and V EPW may be a better predictor because it provides a more specific description of a lesion. This conjecture was not validated here because almost all lesions investigated were chronic and no contrast medium was used.…”

Section: Discussionmentioning

confidence: 99%

Utility of a Multiparametric Quantitative MRI Model That Assesses Myelin and Edema for Evaluating Plaques, Periplaque White Matter, and Normal-Appearing White Matter in Patients with Multiple Sclerosis: A Feasibility Study

Hagiwara

Hori²,

Yokoyama

et al. 2016

BACKGROUND AND PURPOSE: T1 and T2 values and proton density can now be quantified on the basis of a single MR acquisition. The myelin and edema in a voxel can also be estimated from these values. The purpose of this study was to evaluate a multiparametric quantitative MR imaging model that assesses myelin and edema for characterizing plaques, periplaque white matter, and normal-appearing white matter in patients with MS.