Quantitative Susceptibility Mapping in Multiple Sclerosis

Abstract

Purpose:To apply quantitative susceptibility mapping (QSM) in the basal ganglia of patients with multiple sclerosis (MS) and relate the findings to R2* mapping with regard to the sensitivity for clinical and morphologic measures of disease severity. Materials and Methods:The local ethics committee approved this study, and all subjects gave written informed consent. Sixty-eight patients (26 with clinically isolated syndrome, 42 with relapsing-remitting MS) and 23 control subjects underwent 3-T magnetic resonance (MR) imaging. Susceptibility and R2* maps were reconstructed from the same three-dimensional multiecho spoiled gradient-echo sequence. Mean susceptibilities and R2* rates were measured in the basal ganglia and were compared between different phenotypes of the disease (clinically isolated syndrome, MS) and the control subjects by using analysis of variance, and regressing analysis was used to identify independent predictors. Results:Compared with control subjects, patients with MS and clinically isolated syndrome had increased (more paramagnetic) magnetic susceptibilities in the basal ganglia. R2* mapping proved less sensitive than QSM regarding group differences. The strongest predictor of magnetic susceptibility was age. Susceptibilities were higher with increasing neurologic deficits (r = 0.34, P , .01) and lower with normalized volumes of gray matter (r = 20.35, P , .005) and the cortex (r = 20.35, P , .005). Conclusion:QSM provides superior sensitivity over R2* mapping in the detection of MS-related tissue changes in the basal ganglia. With QSM but not with R2* mapping, changes were already observed in patients with clinically isolated syndrome, which suggests that QSM can serve as a sensitive measure at the earliest stage of the disease.q RSNA, 2013

Usefulness of Quantitative Susceptibility Mapping for the Diagnosis of Parkinson Disease

“…11,31-34 Our ROC and interobserver agreement results here show that QSM is more accurate than R2* mapping for measuring substantia nigra change in PD; this finding is consistent with that in a recent study showing that QSM is more accurate than R2* mapping in measuring basal ganglia change in multiple sclerosis. 23 Therefore, QSM may replace R2* mapping for MR imaging measurement of iron-associated change in the brain.…”

“…21,22 Clinical data from patients with multiple sclerosis suggest that QSM is more sensitive than R2* mapping in detecting changes in multiple sclerosis brains. 23 According to a previously published study using QSM, a significant difference was not found between patients with PD and healthy control subjects for the susceptibility value of the substantia nigra. 24 However, because only 9 patients were available for the previous study, the clinical potential of QSM has not been fully elucidated.…”

The Prognostic Utility of MRI in Clinically Isolated Syndrome: A Literature Review

“…However, iron deposition was noted in the absence of any significant volume change. In addition to R2* relaxometry, Langkammer et al 90 performed quantitative susceptibility mapping on 26 subjects with CIS. Quantitative susceptibility mapping detects magnetic charge variations attributable not only to iron, but also but also to myelin.…”

“…Apparently conflicting results by these 2 recently published studies may be attributable to differences in image processing techniques. Langkammer et al 90 …”

MRI in the assessment and monitoring of multiple sclerosis: an update on best practice

“…112,130 The presence of iron is suggestive of microglia activity, and positive signal has been associated with chronic active MS lesions. 34,[131][132][133][134][135][136][137][138][139][140][141] Longitudinal QSM studies, conducted in our center, showed that lesion susceptibility increased as the lesion evolved from contrast enhanced to nonenhanced, indicating that it could be used as a biomarker. [142][143][144] All of these advanced magnetic resonance modalities require further validation in larger cohorts of patients and over a longitudinal time span.…”