Abstract
BACKGROUND AND PURPOSE: Increasing evidence suggests that iron deposition is present in the later stages of MS. In this study we examined abnormal phase values, indicative of increased iron content on SWI-filtered phase images of the SDGM in CIS patients and HC. We also examined the association of abnormal phase with conventional MR imaging outcomes at first clinical onset.
MATERIALS AND METHODS: Forty-two patients with CIS (31 female, 11 male) and 65 age and sex-matched HC (41 female, 24 male) were scanned on a 3T scanner. Mean age was 40.1 (SD = 10.4) years in patients with CIS, and 42.8 (SD = 14) years in HC, while mean disease duration was 1.2 years (SD = 1.3) in patients with CIS. MP-APT, NPTV, and normalized volume measurements were derived for all SDGM structures. Parametric and nonparametric group-wise comparisons were performed, and associations were determined with other MR imaging metrics.
RESULTS: Patients with CIS had significantly increased MP-APT (P = .029) and MP-APT volume (P = .045) in the pulvinar nucleus of the thalamus compared with HC. Furthermore, the putamen (P = .004), caudate (P = .035), and total SDGM (P = .048) displayed significant increases in MP-APT volume, while MP-APT was also significantly increased in the putamen (P = .029). No global or regional volumetric MR imaging differences were found between the study groups. Significant correlations were observed between increased MP-APT volumes of total SDGM, caudate, thalamus, hippocampus, and substantia nigra with white matter atrophy and increased T2 lesion volume (P < .05).
CONCLUSION: Patients with CIS showed significantly increased content and volume of iron, as determined by abnormal SWI-phase measurement, in the various SDGM structures, suggesting that iron deposition may precede structure-specific atrophy.
ABBREVIATIONS:
- CIS
- clinically isolated syndrome
- EDSS
- Expanded Disability Status Scale
- ETL
- echo-train length
- FIRST
- fMRI-integrated registration and segmentation tool
- Gd
- gadolinium
- GM
- gray matter
- HC
- healthy controls
- LV
- lesion volume
- MP-APT
- mean phase of the abnormal phase tissue
- NBV
- normalized brain volume
- NGMV
- normalized gray matter volume
- NLVV
- normalized lateral ventricle volume
- NPTV
- normal phase tissue volume
- NWMV
- normalized white matter volume
- pFOV
- phase FOV
- RRMS
- relapsing-remitting MS
- SDGM
- subcortical deep GM
- © 2012 by American Journal of Neuroradiology
Indicates open access to non-subscribers at www.ajnr.org