An approach for the measurement of the surface area of scalp flap over the cranial defect after decompressive craniectomy / 中国医疗器械杂志

<p><b>OBJECTIVE</b>To introduce a simple, fast and universal measuring method used in measurement of the surface area of scalp flap over the cranial defect after decompressive craniectomy.</p><p><b>METHODS</b>The first step: CT images of the patient with craniocerebral trauma after decompressive craniectomy were obtained and imported into Mimics. The second step: based on the defined threshold, the 3D geometric models of brain and skull were reconstructed after the original Dicom format pictures three-dimensional processed by Mimics. The third step: based on the two builded 3D models, utilizing the segmentation and measurement tools of Mimics to conduct cutting, splitting and measuring operations for the 3D model of brain. The forth step: estimating the surface area of scalp flap over the removed bone flap by using mathematical computation methods.</p><p><b>RESULTS</b>The application of the introduced method estimated the surface area of scalp flap over the cranial defect of different people with different position of craniocerebral trauma.</p><p><b>CONCLUSIONS</b>This paper introduces a simple, fast and universal new measuring method. We can conveniently estimate the surface area of scalp flap by using the introduced method.</p>

Using CTS and PK-PD models to predict the effect of uncertainty about population parameters on clinical trial power / 生物医学工程学杂志

The traditional clinical trail designs always depend on expert opinions and lack statistical evaluations. In this article, we present a method and illustrate how population parameter uncertainty may be incorporated in the overall simulation model. Using the techniques of clinical trail simulation (CTS) and setting up predictions on the basis of pharmacokinetics-pharmacodynamics (PK-PD) models, we advance the modeling methods for simulation, for treatment effects, and for the clinical trail power under the given PK-PD conditions. Then we discuss the model of uncertainty, suggest an ANOVA-based method, add eta2 statistics for sensitivity analysis, and canvass the effect of uncertainty about population parameters on clinical trail power. The results from simulations and the indices derived from this type of sensitivity analysis may be used for grading the influence on the prediction quality of uncertainty about different population parameters. The experiment results are satisfactory and the approach presented has practical value in clinical trails.

Evaluation studies of ultrasonic image features extraction for cervical lymph nodes / 生物医学工程学杂志

Abstract Ultrasonic image features of cervical lymph nodes were extracted by a computerized scheme. The scheme quantified the parameters of shape, border, cortex to medulla ratio, distributing of medulla, long axis to short axis ratio, vascular density and vascular pattern features. Then correlations between the experts andthe computerized scheme for assessing parameters in corresponding categories were computed to evaluate the validity of the parameters extracted by the computer. 106 cervical lymph nodes were studied, and the results showed that good agreement was seen in NRL (normalized radial length) zero crossing count, convex hull depth, long axis to short axis ratio, the vascular density and the entropy of the blood mapping boundary points' distribution.

Monitoring rehabilitation system for the cervical spine based on computer software / 中国组织工程研究

BACKGROUND:Conventional rehabilitation evaluation call not provide more objective data for analysis,so all innovative method to monitor rehabilitation of the cervical spine is introduced.OBJECTIVE:The monitoring rehabilitation system of the cervical spine develops independently under Visual Basic 6.0 environment.It can gather both video and photos at dynamic and static states.According to the suitable feature points of the video,the system could calculate characteristic parameters,such as moving angles,distances,speed,acceleration,and integral curves.Thus,the system could create patients'database.RESULTS:The system could calculate different kinds of patients'characteristic parameters through data recording.Through the objective comparison of characteristic parameters,the turning flexibility of head and controlling capability for head turning could be reflected.CONCLUSl0N:The design is an innovation in the monitoring rehabilitation systems of the cervical spine.It makes up the shortcomings of conventional rehabilitation evaluation and objectively reflects the rehabilitation status of patients.

The Doppler fetal heart rate detection with wavelet transform / 生物医学工程学杂志

Various interference and noises should be eliminated while picking up the signal of fetal heart rate from the Doppler fetal signal in order to obtain smooth curve of the fetal heart Doppler signal and so to figure out the fetal heart rate. In this study, the mean frequency shift curve estimated from the Doppler fetal signals was smoothed using wavelet transform. The results showed that the fetal-heart rate obtained by computing from the autocorrelation waveform based on the smoothed mean frequency shift curve was more accurate than that based on unsmoothed curve.

Application of Burg algorithm in time-frequency analysis of Doppler blood flow signal based on AR modeling / 生物医学工程学杂志

The Doppler blood flow signal is inherently a nonstationary Gaussian random process whose time-frequency representation associates with the time-varying velocity of blood flow and its variations. With the assumption that the signal being analyzed is stationary during a short time interval, we can not get Doppler time-frequency representations with satisfactory time and frequency resolution. AR modeling based on Levinson-Durbin algorithm has been used to generate time-frequency representations of Doppler blood flow signals. But the errors of the parameters computed by the algorithm will be aggrandized by the shortening of the time interval. Burg has advanced an algorithm, which computes the parameters by making the sum of forward and backward forecasting errors minimum. In the paper, time-frequency representations computed by Burg and Levinson-Durbin algorithm were compared with the theoretical representation. We found that the time-frequency representations computed by Burg algorithm are more similar to the theoretical representation, especially in frequency band.