An Automatic Method for Generating an Unbiased Intensity Normalizing Factor in Positron Emission Tomography Image Analysis After Stroke / 神经科学通报·英文版

Positron emission tomography (PET) imaging of functional metabolism has been widely used to investigate functional recovery and to evaluate therapeutic efficacy after stroke. The voxel intensity of a PET image is the most important indicator of cellular activity, but is affected by other factors such as the basal metabolic ratio of each subject. In order to locate dysfunctional regions accurately, intensity normalization by a scale factor is a prerequisite in the data analysis, for which the global mean value is most widely used. However, this is unsuitable for stroke studies. Alternatively, a specified scale factor calculated from a reference region is also used, comprising neither hyper- nor hypo-metabolic voxels. But there is no such recognized reference region for stroke studies. Therefore, we proposed a totally data-driven automatic method for unbiased scale factor generation. This factor was generated iteratively until the residual deviation of two adjacent scale factors was reduced by < 5%. Moreover, both simulated and real stroke data were used for evaluation, and these suggested that our proposed unbiased scale factor has better sensitivity and accuracy for stroke studies.

Characteristics of brain functional alterations and task functional magnetic resonance imaging in patients with Cushing's disease / 解放军医学杂志

Objective To analyze the relationship between the brain functional alterations of patients with Cushing's disease (CD) and patients' mental symptom by applying the Evaluating Emotional Scales and task functional magnetic resonance imaging (Task fMRI).Methods Task fMRI was performed on 8 patients with diagnosed CD admitted in the Department of Endocrinology of Chinese PLA General Hospital from Nov. 2015 to Nov. 2016 and 21 healthy people with matched age, gender and education level as control. Meanwhile, Self-Rating Depression Scale (SDS), Self-Rating Anxiety Scale (SAS), Positive and Negative Affective Scale (PANAS) and Cushing Quality of Life Scale (Cushing QOL) were obtained to assess the brain functions.Results Significant depression and anxiety were observed in patients with CD, and their positive affective score was substantially lower while the negative affective score was relatively higher compared with that in the controls. Task fMRI revealed that, when watching the positive pictures, the activation degree of left cerebellum and right postcentral gyrus weakened in CD patients than in the controls, and the positive correlations existed between the activation degree of left cerebellum and the 16 o'clock adrenocorticotrophic hormone (ACTH) level, and between the activation degree of right postcentral gyrus and the urinary free cortisol (UFC) level in CD patients. In contrast, when watching the negative pictures, the activation degree of left cerebellum, bilateral parahippocampal gyrus and left inferior frontal gyrus was weakened in CD patients than in the controls, and the activation degree of left cerebellum was negatively correlated to the 0 o'clock cortisol level and SAS score, but is positively correlated to the UFC level. When watching the neutral pictures, the activation degree of left cerebellum and left parahippocampal gyrus was weakened in CD patients than in the controls.Conclusions CD patients may have impaired brain function with depression and anxiety mental symptoms. By Task fMRI, it can be found that the weakened activation degree of left inferior frontal gyrus, right postcentral gyrus, bilateral parahippocampal gyrus and left cerebellum may be related to CD patients' mental symptoms.