Chunheng Wang

Quantification of the Human Lateral Geniculate Nucleus In Vivo Using MR Imaging Based on Morphometry: Volume Loss with Age

BACKGROUND AND PURPOSE: Because it is a small subcortical structure, the precise measurement of the human LGN is still a technical challenge. In this article, we identify the LGN in vivo, measure its volume based on high-resolution MR imaging, and then relate its volume to subject age to evaluate the potential clinical application. MATERIALS AND METHODS: A semiautomatic LGN isolation method was developed on scans obtained with 1.5T MR imaging, which involves highlighting the surrounding landmarks, obtaining candidate LGN voxels with a region-growing algorithm, and isolating the LGN from the ventral diencephalon. The method was accessed with a test-retest reliability on the results from 55 healthy subjects at different ages. RESULTS: This method showed high test-retest within-subject reliability (ICC, 0.950 and 0.948 in left and right hemispheres, respectively) among 3 independent measurements in each subject. The unilateral volume was highly variable, ranging from 52 to 102 mm3 in the left and 66 to 105 mm3 in the right hemisphere, with significantly larger volumes on the right (86 mm3) than on the left (77 mm3). The combined bilateral volumes (controlled for ICV) significantly decreased in size with progressing age from 20 to 65 years (r = −0.512, P = .000). There was no sex difference in bilateral LGN volumes (male/female: 163.1 ± 18.2/162.2 ± 21.4 mm3). CONCLUSIONS: Using our new technique, we were able to reliably determine the human LGN volume in vivo, which was found to decline with age. The volumes obtained by our method corresponded well with previously reported postmortem values, so our method may be considered to be superior for investigating the pathology of LGN.

Alterations of grey matter asymmetries in adolescents with prelingual deafness: a combined VBM and cortical thickness analysis.

PURPOSE Prelingual deafness has been shown to lead to brain reorganization as demonstrated by functional parameters, but anatomical evidences still remain controversial. The present study investigated hemispheric asymmetry changes in deaf subjects using MRI, hypothesizing auditory-, language- or visual-related regions after early deafness. METHODS Prelingually deaf adolescents (n = 16) and age- and gender-matched normal controls (n = 16) were recruited and hemispheric asymmetry was evaluated with voxel-based morphometry (VBM) from MRI combined with analysis of cortical thickness (CTh). RESULTS Deaf adolescents showed more rightward asymmetries (L < R) of grey matter volume (GMV) in the cerebellum and more leftward CTh asymmetries (L > R) in the posterior cingulate gyrus and gyrus rectus. More rightward CTh asymmetries were observed in the precuneus, middle and superior frontal gyri, and middle occipital gyrus. The duration of hearing aid use was correlated with asymmetry of GMV in the cerebellum and CTh in the gyrus rectus. Interestingly, the asymmetry of the auditory cortex was preserved in deaf subjects. CONCLUSIONS When the brain is deprived of auditory input early in life there are signs of both irreversible morphological asymmetry changes in different brain regions but also signs of reorganization and plasticity which are dependent on hearing aid use, i.e. use-dependent.

Fighting link spam with a two-stage ranking strategy

Most of the existing combating web spam techniques focus on the spam detection itself, which are separated from the ranking process. In this paper, we propose a two-stage ranking strategy, which makes good use of hyperlink information among Websites and Websites intra structure information. The proposed method incorporates web spam detection into the ranking process and penalizes the ranking score of potential spam pages, instead of removing them arbitrarily. Preliminary experimental results show that our method is feasible and effective.

CWME: a framework of group support system for emergency responses

As the world becomes more and more interconnected and complex, the emergent events, such as terrorist acts, infectious diseases and natural disasters challenge the rapid response ability of the public and the governments more and more. In general, emergency responses always involve so many complex problems that it beyond the decision capacity of a single person or organization. To meet this challenge, some new approaches of decision support for emergency responses need to be discovered. In this paper, a framework of this type of system, CWME, is introduced. It’s based on the theories for Open Complex Giant Systems[1]. The key point of this system is to synthesize the intelligence of experts, the high performance of computers and data, information to understand the problems comprehensively and to make better decisions.

Segmentation of mixed chinese/english document including scattered italic characters

It is difficult to segment mixed Chinese/English documents when there are many italic characters scattered in documents. Most contributions attach more attention to English documents. However, mixed document is different from English document and some special features should be considered. This paper gives a new way to solve the problem. At first, an appropriate character area is chosen to detect italic. Next, a two-step strategy is adopted. Italic determination is done first and then if the character pattern is identified as italic, the estimation of slant angle will be done. Finally the italic character pattern is corrected by shear transform. A method of adopting two-step weighted projection profile histogram for italic determination is introduced. And a fast algorithm to estimate slant angle is also introduced. Three large sample collections, including character and character-pair and document respectively, are provided to evaluate our method and encouraging results are achieved.

Correcting bound document images based on automatic and robust curved text lines estimation

Geometric distortion often occurs when taking images of bound documents. This phenomenon greatly impairs recognition accuracy. In this paper, a new one-image based method is proposed to correct geometric distortion in bound document images. According to this method, the document image is binarized first. Next, curved text-line features are extracted. Thirdly, locally optimized text curves are detected using a graph model. Finally, the technique of texture warping is applied to correct the image. Experimental results show that images restored by our proposed method can achieve good perception and recognition results.

Abnormalities of hippocampal-cortical connectivity in temporal lobe epilepsy patients with hippocampal sclerosis

Hippocampal sclerosis (HS) is the most common damage seen in the patients with temporal lobe epilepsy (TLE). In the present study, the hippocampal-cortical connectivity was defined as the correlation between the hippocampal volume and cortical thickness at each vertex throughout the whole brain. We aimed to investigate the differences of ipsilateral hippocampal-cortical connectivity between the unilateral TLE-HS patients and the normal controls. In our study, the bilateral hippocampal volumes were first measured in each subject, and we found that the ipsilateral hippocampal volume significantly decreased in the left TLE-HS patients. Then, group analysis showed significant thinner average cortical thickness of the whole brain in the left TLE-HS patients compared with the normal controls. We found significantly increased ipsilateral hippocampal-cortical connectivity in the bilateral superior temporal gyrus, the right cingulate gyrus and the left parahippocampal gyrus of the left TLE-HS patients, which indicated structural vulnerability related to the hippocampus atrophy in the patient group. However, for the right TLE-HS patients, no significant differences were found between the patients and the normal controls, regardless of the ipsilateral hippocampal volume, the average cortical thickness or the patterns of hippocampal-cortical connectivity, which might be related to less atrophies observed in the MRI scans. Our study provided more evidence for the structural abnormalities in the unilateral TLE-HS patients.

Providing personalized services for HWME system by item-based collaborative filtering

The Hall for Workshop of Metasynthetic Engineering (HWME) is a methodology that can be used to deal with problems in open complex giant systems, such as strategic decisions of national emergency actions. The discussion process is the key component of the HWME system, in which the generalized experts provide a valuable knowledge to human experts. In this paper, a novel framework is proposed, which can explore the personalized information of generalized experts. An item-based collaborative filtering approach is adopted to recommendation for HWME system. Under this framework, human experts can make the best use of information provided by the generalized experts and then give a more effective judgment.

Cyberspace community analysis and simulation using complex dynamic social networks

Social network analysis (SNA) is the study of social relations among a set of actors. It is an emerging discipline that maps and measures the relationships between people, groups, organizations, computers or other information processing entities. SNA has been widely applied into many areas [1-3].