Central intra-lesional iron deposits as a possible novel imaging marker at 7 Tesla MRI in Susac Syndrome - an exploratory study.

BACKGROUND: Susac syndrome (SuS) is a rare autoimmune disease that leads to hearing impairment, visual field deficits, and encephalopathy due to an occlusion of precapillary arterioles in the brain, retina, and inner ear. Given the potentially disastrous outcome and difficulties in distinguishing SuS from its differential diagnoses, such as multiple sclerosis (MS), our exploratory study aimed at identifying potential new SuS-specific neuroimaging markers. METHODS: Seven patients with a definite diagnosis of SuS underwent magnetic resonance imaging (MRI) at 7 Tesla (7T), including T2* weighted and quantitative susceptibility mapping (QSM) sequences. T2 weighted hyperintense lesions were analyzed with regard to number, volume, localization, central vein sign, T1 hypointensity, and focal iron deposits in the center of SuS lesions ("iron dots"). Seven T MRI datasets from the same institute, comprising 75 patients with, among others, MS, served as controls. RESULTS: The "iron dot" sign was present in 71.4% (5/7) of the SuS patients, compared to 0% in our control cohort. Thus, sensitivity was 71.4% and specificity 100%. A central vein sign was only incidentally detected. CONCLUSION: We are the first to demonstrate this type of "iron dot" lesions on highly resolving 7T T2*w and QSM images in vivo as a promising neuroimaging marker of SuS, corroborating previous histopathological ex vivo findings.

Is electrical cardioversion independently associated with infarcts on brain magnetic resonance imaging or clinical outcomes in patients with atrial fibrillation?

BACKGROUND: Electrical cardioversion (ECV) is frequently performed in symptomatic atrial fibrillation. OBJECTIVE: This study aimed to assess the association of ECV with infarcts on brain magnetic resonance imaging (bMRI) and clinical outcomes. METHODS: The Swiss Atrial Fibrillation Cohort Study included 2386 patients; 1731 patients were evaluated by bMRI. ECVs were recorded by questionnaire. Patients were assigned to categories by number of ECVs performed before enrollment (0, 1, ≥2). A bMRI study was conducted at baseline and after 2 years (n = 1227) and analyzed for large noncortical or cortical infarcts and small noncortical infarcts. Clinical outcomes were recorded during follow-up. Associations of ECV and outcome measures were assessed by multivariate analyses. RESULTS: There was no independent association between the number of ECVs and infarct prevalence (large noncortical or cortical infarcts and small noncortical infarcts) on baseline bMRI (ECV 1 vs 0: odds ratio [OR], 0.95 [95% CI, 0.68-1.24]; ECV ≥2 vs 0: OR, 1.04 [0.72-1.44]) or between ECVs performed during follow-up and new infarcts on bMRI at 2 years (OR, 1.46 [0.54-3.31]). ECVs were not associated with overt stroke or transient ischemic attack (ECV 1 vs 0: hazard ratio [HR], 1.36 [0.88-2.10]; ECV ≥2 vs 0: HR, 1.53 [0.94-2.48]), hospitalization for heart failure (ECV 1 vs 0: HR, 1.06 [0.82-1.37]; ECV ≥2 vs 0: HR, 1.03 [0.77-1.38]), or death (ECV 1 vs 0: HR, 0.90 [0.70-1.15]; ECV ≥2 vs 0: HR, 0.91 [0.69-1.20]). CONCLUSION: There was no association between ECV performed before enrollment and cerebral infarcts on baseline bMRI or between ECV performed during follow-up and new infarcts at 2 years. Moreover, ECV was not associated with clinical events.