[Medical imaging clinical appropriateness:rational examination according to evidence-based medical imaging].

The rational clinical examination is important. The authors raised the concept of "medical imaging clinical appropriateness (MICA) " to meet the medical need in clinic (for diagnosis or assessment of a kind of disease or syndrome), which means radiologists and clinicians work together to carefully evaluate the necessity and rationality of an examination according to evidence of evidence-based medicine, expertise, experience, and patient's willing.The necessity is prerequisite, the rationality is the core, the evaluation of evidence is the basis, the application of evidence-based medicine is the important method. This work will provide us a series of criteria in the format of guidelines, providing evidence of rational examination for clinicians. Based on hard working and cooperation between radiologists and clinicians, we will establish the system of MICA in China, standardizing medical process, promoting rationalization, optimizing medical resources allocation and usage.

MR Diffusional Kurtosis Imaging-Based Assessment of Brain Microstructural Changes in Patients with Moyamoya Disease before and after Revascularization.

BACKGROUND AND PURPOSE: Conventional imaging examinations are insufficient to accurately assess brain damage in patients with Moyamoya disease. Our aim was to observe brain microstructural changes in patients with Moyamoya disease by diffusional kurtosis imaging and provide support data for application of this technique in individualized assessment of disease severity and surgical outcome among patients with Moyamoya disease. MATERIALS AND METHODS: A total of 64 patients with Moyamoya disease and 15 healthy volunteers underwent diffusional kurtosis imaging, and a second scanning was offered to surgical patients 3-4 months after revascularization. The diffusional kurtosis imaging parameter maps were obtained for mean kurtosis, axial kurtosis, radial kurtosis, fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity. The parameter values were measured in sensory pathway-related regions for all subjects. Differences in diffusional kurtosis imaging parameters of these brain regions were examined for healthy volunteers, patients without acroparesthesia, and asymptomatic and symptomatic sides of patients with acroparesthesia. Changes in diffusional kurtosis imaging parameters of patients with Moyamoya disease before and after revascularization were compared. RESULTS: Compared with healthy volunteers, patients with Moyamoya disease showed decreased mean kurtosis, axial kurtosis, radial kurtosis, and fractional anisotropy in the corona radiata. Similarly, mean kurtosis, radial kurtosis, and fractional anisotropy decreased in the posterior limb of the internal capsule, whereas axial kurtosis decreased and radial kurtosis increased in the thalami of patients with Moyamoya disease compared with healthy volunteers. Compared with the asymptomatic contralateral hemisphere, the symptomatic group showed increased mean kurtosis in the contralateral primary somatosensory cortex, increased fractional anisotropy in the contralateral corona radiata and posterior limb of the internal capsule, and decreased axial kurtosis in the contralateral thalamus. Among patients with Moyamoya disease with acroparesthesia, mean kurtosis decreased in the primary somatosensory cortex on the operated side following revascularization. CONCLUSIONS: The diffusional kurtosis imaging technique is applicable to patients with Moyamoya disease for detecting brain microstructural changes in white and gray matter before and after revascularization; this feature is useful in the assessment of disease severity and surgical outcome.

Developing an Integrated Modeling Tool for River Water Quality Index Assessment.

The goal of this study was to establish a modeling tool for river water quality with a direct linkage to the water quality index (WQI5) calculation and the river water quality model, the Water Quality Analysis Simulation Program (WASP), for pollutant transport modeling. The integrated WASP and WQI5 tool was field-tested to assess pollutant loadings and their impacts on river environment. Suspended solid (SS) and electric conductivity (EC) correlation equations and the WQI5 calculation tool were included in the water quality model and direct WQI5 calculation. The SS concentration, which was influenced by river flows, had crucial effects on river water quality and WQI5 values. EC value was controlled by dissolution of soil minerals, which was affected by the watershed drainage area and surface runoff. The integrated system could establish a direct correlation for river water quality, river flow, and WQI5.

External quality assessment survey for hematological laboratories in China.

To evaluate the feasibility of improving external quality assessment (EQA), we set up an experimental EQA survey that included 465 participants in China. During the period of this survey, we checked the quality of the EQA samples, divided the participants into different groups, each laboratory's result was assessed by calculation standard deviation index (SDI). The reference values were determined to evaluate the accuracy for peer groups. The data showed that the stability of the EQA samples was acceptable. Except for WBC count of the Abbott group, the mean, median and reference values for each parameter were very close. We found that the main reason affecting the performance of the participants was not using the reagents. calibrator and QC material recommended by manufacturer. From this survey, we obtain a good reference for future improvement.

Study of simplified measures for malaria surveillance in the late consolidation phase in China.

This paper presents the results of a study on simplified surveillance methods conducted in 23 pilot counties in 11 provinces and municipalities in China where reside 15 million people and malaria control has been in the late consolidation phase. Two simplified surveillance Schemes (A and B) taking treatment of clinical cases as the main measure were implemented in 1992-1994. The rate of annual blood examination for case detection was 1.0% in pilot Scheme A, while in areas of scheme B it was 0.3%. The implementation of both Scheme A and Scheme B, simplified or without treatment of infection foci and management of mobile populations, acquired satisfactory effects against malaria. Consequently, malaria incidence was declining steadily, only a few indigenous and introduced cases were detected. The parasite rate in residents and the IFA positive rate in children were very low. The results of pilot studies and cost-effectiveness analysis indicated that Scheme B is effective, rational and economic, and can be implemented to replace the routine surveillance measures in areas where malaria has been at the late consolidation phase in China.

Molecular epidemiology of tuberculosis in Denmark in 1992.

The incidence of tuberculosis (TB) is increasing all over the world, including in countries with a high standard of living and good social security. Denmark represents such a region. Furthermore, it is a small country (5 million inhabitants) with a long tradition in TB control, including a centralization of the bacteriological diagnostic facility. The present study was intended to analyze the transmission of Mycobacterium tuberculosis in a country in which TB has low endemicity by a combination of conventional epidemiological approaches and DNA fingerprinting techniques, whereby individual bacterial strains can be traced. M. tuberculosis isolates from 92% of all new cases of bacteriologically verified TB in Denmark during 1992 were subjected to IS6110 DNA fingerprinting to visualize the DNA restriction fragment length polymorphism (RFLP) patterns of the isolated strains. The data obtained from the RFLP analyses were interpreted by using demographic data, such as age, sex, ethnicity, and residence, for the patients. The risk factors among the patients for being part of an active chain of transmission, as opposed to demonstrating reactivation of a previously acquired latent infection, were estimated by statistical analyses. The magnitude of TB transmission in 1992 in Denmark was determined, and transmitted infections were shown to comprise at least one quarter of the total number of cases. Almost half of the TB cases involved patients of foreign origin. However, most of these isolates showed unique DNA fingerprint patterns and were rarely part of an active chain of transmission. The major chains of recent transmission were localized to distinct geographical regions in the country. TB is frequent among immigrants, especially from Asia and Africa, but it is apparently readily suspected, diagnosed, and treated by the health care system. Danish patients with pulmonary symptoms are not primarily suspected to have TB and, therefore, play an important role in recent TB transmission in Denmark.

[Effects of longterm selection on the genetic structure of populations--a simulation study. I. Simulation models and selection responses].

Monte Carlo method has been utilized to investigate responses to longterm selection. The simulation involves 3 gene effect models (additive, dominant, and over-dominant), two population sizes, three linkage intensities, and three heritability levels, thus making 54 combinations. For each combination, 5 replicate populations are selected over 49 consecutive non-overlapping generations. The results demonstrate that under all the gene effect models, linkage is important only in the case of small populations and intense linkage, when it reduces responses significantly due to hampering the fixation of favourable alleles and accelerating their loss. Linkage has no apparent effect if it is not very tight or if the population is large. Much greater responses are achieved in the large populations than in the small ones, especially for traits with low heritability. Among those discussed are problems of crossing selected lines to obtain extra responses, and discrepancy of some theoretic results on selection limits.

[A tentative discussion on the reproduction of population in China].

PIP: Population reproduction is a physiological phenomenon necessary to continue the human race, replacing the older generation with a new one. Population reproduction is also closely related to material production. Both are mutually restricted and supportive of each other. Population reproduction can be divided into 2 types: 1) short life span and rapid generation replacement or high birth rate and high mortality rate, and 2) long life span and slow generation replacement or low birth rate and low mortality rate. Since 1949 China has significantly reduced the mortality rate because of the improvement of our health system and working conditions and the increased living standard. The birth rate, however, still remains high because we are a developing country and our levels of education, science, and technology are quite low. This intermediate stage of low mortality rate but high birth rate also existed in most developed countries for several decades. China's large population and high population growth rate severely inhibit the development of social production and the achievement of the "Four Modernizations." The only way to resolve this contradiction of population reproduction and development of productivity is to control the population growth. Family planning and advocation of 1 child per couple are important strategic tasks in realizing the "Four Modernizations."^ieng