With Doppler spectrum analysis,resistance index in primary malignant tumors was 0.77±0.12,in metastatic tumors that was 0.71±0.07,whereas the average RI in benign lesions was below 0.6.The difference was significant.
Results All patients with postabortal intrauterine fetal residue were diagnosed by pathology,58 patients with much intraulerine fetal residue and 71 patients with less intrauterine fetal residue,2 cases with fetal residue in cervix,the display rate of colour flow was 93.2%, the pulsed wave Doppler spectrum showed lower resistance: RI 0.46±0.11.Conclusion TVS-CD has a certain diagnostic value in dectecting the incomplete abortion.
Analysis of the experiment results under differentconditions reveals the effects of the different SNRs and the Doppler spectrum forms onthe accuracy of the correlation method, thus providing a guideline for the application ofthe method.
Based on the differences of Doppler spectrum signatures,two micro-Doppler features are presented for helicopter identification. One feature describes the asymmetry of Doppler spectrum distribution,and the other shows the contrast between the energy of echo-signals from fuselage and that from blades. Finally a simulation with synthetic data and experiment data is presented,and the simulation result shows the validity of the method.
In the second chapter, a wideband MIMO channel model with multiple-tap was integrated according to the angle of departure of the transmitting signal and its spread angle, the angle of arrival of the receiving signal and its spread angle, power azimuth spectra, Doppler spectrum and the geometric construction of antenna array both sides of transmit and receive, on the basis of full research on the theories of space-time channel model proposed in the recent literature.
QTVI found abnormal diastolic function in patients even with the normal value of VE/VA. Furthermore,QTVI was able to demonstrate localized ventricular movement and seems more sensitive than the Doppler spectrum analysis.
Objective To compare the value of conventional ultrasonography (US, including gray-scale ultrasonography, color Doppler flow imaging and Doppler spectrum) and ultrasonic elastography (UE) in differentiating the benign and malignant breast lesions.
Methods In 28 patients with hypertrophic cardiomyopathy left anterior descending artery and interventricular septum branch flow were displayed using coronary flow Doppler imaging system before and after PTSMA,and flow velocity were measured by Doppler spectrum.
Important channel parameters measured at the mobile terminal such as the angular power distribution, Doppler spectrum, and multipath shape factors are also investigated to further exemplify the usefulness of the proposed model.
The analysis provides the required information about the temporal stability of the channel, the probability of occurrence and depth of fades, the Doppler spectrum and, in general, the influence of the environment on the signal behaviour.
In particular, the slow time varying nature of the channel is studied and the narrow Doppler spectrum shape is approximated.
The simulations are conducted in a multipath channel with Rayleigh fading and 300 Hz Doppler spectrum with additive white Gaussian noise.
Comparison with the experimental data shows that the developed theoretical model of a Doppler spectrum is in good agreement with the observations.