Regional Shape Abnormalities in Thalamus and Verbal Memory Impairment After Subcortical Infarction.

Background. Subcortical infarcts can result in verbal memory impairment, but the potential underlying mechanisms remain unknown. Objective. We investigated the spatiotemporal deterioration patterns of brain structures in patients with subcortical infarction and identified the regions that contributed to verbal memory impairment. Methods. Cognitive assessment and structural magnetic resonance imaging were performed 1, 4, and 12 weeks after stroke onset in 28 left-hemisphere and 22 right-hemisphere stroke patients with subcortical infarction. Whole-brain volumetric analysis combined with a further-refined shape analysis was conducted to analyze longitudinal morphometric changes in brain structures and their relationship to verbal memory performance. Results. Between weeks 1 and 12, significant volume decreases in the ipsilesional basal ganglia, inferior white matter, and thalamus were found in the left-hemisphere stroke group. Among those 3 structures, only the change rate of the thalamus volume was significantly correlated with that in immediate recall. For the right-hemisphere stroke group, only the ipsilesional basal ganglia survived the week 1 to week 12 group comparison, but its change rate was not significantly correlated with the verbal memory change rate. Shape analysis of the thalamus revealed atrophies of the ipsilesional thalamic subregions connected to the prefrontal, temporal, and premotor cortices in the left-hemisphere stroke group and positive correlations between the rates of those atrophies and the change rate in immediate recall. Conclusions. Secondary damage to the thalamus, especially to the left subregions connected to specific cortices, may be associated with early verbal memory impairment following an acute subcortical infarct.

Advanced-Stage Nasopharyngeal Carcinoma: Restaging System after Neoadjuvant Chemotherapy on the Basis of MR Imaging Determines Survival.

Purpose To evaluate the prognostic value of the restaging system after neoadjuvant chemotherapy (NACT) in patients with advanced-stage nasopharyngeal carcinoma (NPC). Materials and Methods This study was approved by the clinical research committee and a written informed consent was required before enrolling in the study. Prospectively enrolled were 412 consecutive patients with stage III-IVb NPC treated with NACT followed by concurrent chemotherapy and radiation therapy. Patients were staged before NACT and restaged after NACT. The progression-free survival (PFS) and distant metastasis-free survival (DMFS) were calculated with the Kaplan-Meier method, and differences were compared by using the log-rank test. Results Post-NACT T classification (PFS, P = .001) and N classification (PFS, P < .001; DMFS, P = .001) resulted in better survival curve separations than pre-NACT T classification and N classification. Patients downstaged from N2-N3 to N0-N1 disease had a better prognosis than did patients who continued to have N2-N3 diseases (3-year PFS, 83.8% vs 66.6%, P = .001; 3-year DMFS, 88.0% vs 78.4%, P = .026). Multivariate analysis revealed that post-NACT T classification (hazard ratio [HR] = 1.67; 95% confidence interval [CI]: 1.18, 2.36; P = .003) and post-NACT N classification (HR = 1.54; 95% CI: 1.17, 2.03; P = .002) were independent prognostic factors for PFS; also, post-NACT N classification (HR = 1.48; 95% CI: 1.05, 2.07; P = .025) was an independent prognostic factor for DMFS. Multivariate analysis in patients with N2-N3 disease demonstrated that the N downstaging effects of NACT was the only independent prognostic factor for PFS (HR = 0.48; 95% CI: 0.29, 0.81; P = .006) and DMFS (HR = 0.52; 95% CI: 0.28, 0.97; P = .039). Conclusion The post-NACT stage is more representative of prognosis than the pre-NACT stage in advanced-stage NPC patients, which suggests that major clinical decisions should be based on the post-NACT stage. © RSNA, 2016 Online supplemental material is available for this article.