Removing the effect of SVD algorithmic artifacts present in quantitative MR perfusion studies.

Quantitative cerebral blood flow (CBF) values can be obtained from dynamic susceptibility contrast (DSC) MR perfusion studies using the standard singular value decomposition (sSVD) deconvolution algorithm. Reports in the literature from simulation and in vivo studies suggest that CBF estimates obtained using sSVD deconvolution depend on the arterial-tissue delay (ATD). By contrast, Fourier transform (FT) deconvolution produces CBF estimates that are independent of ATD. The diagnostic reliability of quantitative CBF measurements to define areas of normal tissue flow and tissue at risk is brought into doubt by such gross sensitivity to the specifics of the deconvolution approach. This variation of CBF values with ATD is shown to be an artifact associated with the current implementation of the sSVD deconvolution algorithm. A reformulated version of the SVD deconvolution algorithm (rSVD) is presented and compared to the standard SVD algorithm through simulation and patient case studies.     

Quantification of atherosclerotic plaque components using in vivo MRI and supervised classifiers.

In this work we aimed to study the possibility of using supervised classifiers to quantify the main components of carotid atherosclerotic plaque in vivo on the basis of multisequence MRI data. MRI data consisting of five MR weightings were obtained from 25 symptomatic subjects. Histological micrographs of endarterectomy specimens from the 25 carotids were used as a standard of reference for training and evaluation. The set of subjects was divided in a training set (12 subjects) and an evaluation set (13 subjects). Four different classifiers and two human MRI readers determined the percentages of calcified tissue, fibrous tissue, lipid core, and intraplaque hemorrhage on the subject level for all subjects in the evaluation set. Quantification of the relatively small amounts of calcium could not be done with statistical significance by either the classifiers or the MRI readers. For the other tissues a simple Bayesian classifier (Bayes) performed better than the other classifiers and the MRI readers. All classifiers performed better than the MRI readers in quantifying the sum of hemorrhage and lipid proportions. The MRI readers overestimated the hemorrhage proportions and tended to underestimate the lipid proportions. In conclusion, this pilot study demonstrates the benefits of algorithmic classifiers for quantifying plaque components.     

Clinical course and outcome of cycloid psychotic disorder: a three-year prospective study

The course and outcome of cycloid psychotic disorder was explored by means of a prospective three-year follow-up of a sample of patients fulfilling the diagnostic criteria for the disorder provided by Perris & Brockington, compared to patients with a diagnosis of affective or schizoaffective disorder. The most striking difference between cycloids and affectives was the lack of manic episodes during the follow-up period in the former group. Moreover, the mean age at onset was lower in cycloids. No difference between these patient groups was observed with regard to outcome. Compared to schizoaffectives, cycloids showed several differences in the clinical picture during the index episode, and their symptomatological pattern was more consistent from one episode to another during the follow-up. Moreover, the outcome of cycloids was significantly more favourable than that of schizodepres-sives.     

关于卫生监督医疗纠纷类图书归类探析

指出第四版《中图法》中有关卫生监督、医疗事故、医疗纠纷等类目中存在的一些问题和不足,并提出具体改进措施和分类建议。     

A Bayesian approach to subvoxel tissue classification in NMR microscopic images of trabecular bone

NMR microscopy is currently being used as an investigational tool for the evaluation of micromorphometric parameters of trabecular bone as a possible means to assess its strength. Since, typically, the image voxel size is not significantly smaller than individual trabecular elements, partial volume blurring can be a major complication for accurate tissue classification. In this paper, a Bayesian segmentation technique is reported that achieves improved subvoxel tissue classification. Each voxel is subdivided either into eight subvoxels twice the original resolution, or up to four subvoxels along the transaxial direction and the subvoxels optimally classified as either bone or marrow. Based on a statistical model for partial volume blurring, the likelihood for the number of marrow subvoxels in each voxel can be computed on the basis of its measured signal. To resolve the ambiguity of the location of the marrow subvoxels, a Gibbs distribution is introduced to model the interaction between the subvoxels. Neighboring subvoxel pairs with the same tissue label are encouraged, and pairs with distinct labels are penalized. The segmentation is achieved by maximizing the a posteriori probability of the label image using the block ICM (iterative conditional mode) algorithm. The potential of the proposed technique is demonstrated in real and synthetic NMR microscopic images.     

应用单克隆抗体(MoAb)对白血病免疫分型的临床研究

报告了应用单克隆抗体对25例淋巴细胞白血病、5例慢性粒细胞白血病及15例急性非淋巴细胞白血病进行免疫分型并与AB分型作比较,结果提示免疫分型可以弥补FAB分型的不足,它有助于白血病临床诊断、鉴别诊断、指导治疗和判断预后。     

Colonoscopic classification of internal hemorrhoids: Usefulness in endoscopic band ligation

Background:  Bleeding is one of the main symptoms of internal hemorrhoids. However, the conventional Goligher's classification of internal hemorrhoids does not consider the severity of bleeding. We intended to establish a useful method for evaluating internal hemorrhoids using a colonoscope that reflected the severity of the symptoms.
Methods:  Using a colonoscope in the retroflexed and forward viewing position, 104 patients with symptomatic internal hemorrhoids were evaluated based on the criteria of range, form and red color signs (RCS). Range was determined by the circumferential distribution of internal hemorrhoids and scaled from 0 to 4. Form was determined by size and scaled from 0 to 2. The presence of RCS was also evaluated. Symptoms were determined by interview and scaled from 0 to 3. Patients were treated by endoscopic band ligation (EBL) and were examined endoscopically before and 4 weeks after the treatment.
Results:  Before the treatment, range, form and RCS were significantly correlated to bleeding ( P <  0.01), and form was significantly correlated to prolapse ( P <  0.05). The endoscopic classification scores at 4 weeks after EBL improved significantly (range from 3.25 ± 0.05–0.56 ± 0.08 [ P <  0.01] and form from 2.81 ± 0.04–0.56 ± 0.07 P <  0.01).
Conclusion:  The new endoscopic classification of internal hemorrhoids proved to be closely correlated to symptoms, particularly bleeding, and thus highly useful in evaluating the effectiveness of the treatment.     

采用修正正交分段线性函数求解时滞系统和卷积的方法

应用修正正交分段线性函数的时滞和反向特性，推导出求解时滞系统和卷积的公式。数字仿真表明，它具有计算简单，精度高的优点。     

神经网络分析方法用于心脏病诊断的研究

神经网络可以很好的拟合任意的非线性函数。我们从 QRS波群的高频三维频谱中提取出一些定量的特征参数 ,用神经网络的方法对这些参数进行有监督的学习训练 ,最终能在由这些特征参数张成的 m维空间中构建出一个 m维的曲面来区分病人和健康人的 QRS波群高频三维频谱 ,从而使得训练后的网络能基于 QRS波群的高频三维频谱自行诊断出病人和健康人     

Effect of atrial pacing therapy with selective pacing algorithms on paroxysmal atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia among the elderly. Its incidence increases dramatically with increasing age and decreasing left ventrieular function, peaking in subjects with overt congestive heart failure, Because of the unsatisfactory efficacy and possible serious side effects of clinically available anti-AF drugs for AF patients with sick sinus syndrome, pacing techniques have recently been applied in the treatment of AF. The cardiac pacemaker Vitatron