Using catheter-mounted two-dimensional array transducers, we have obtained real-time three-dimensional color flow and spectral Doppler ultrasound images in phantoms. We have constructed several transducers operating at 5 MHz with up to 137 channels inside a 12 French catheter lumen. The transducer configuration may be side scanning or beveled with respect to the long axis of the catheter lumen....

Sub-Doppler broadband multi-heterodyne spectroscopy is proposed and experimentally demonstrated. Using two laser frequency combs of slightly different repetition frequencies, we have recorded Doppler-free two-photon dual-comb spectra of atomic rubidium resonances of a width of 6 MHz, while simultaneously interrogating a spectral span of 10 THz. The atomic transitions are uniquely identified via...

We present a new Doppler estimation for time division duplex (TDD) systems using power spectral density (PSD) based method. First, a detailed analysis of the effect of TDD frame structure is proposed. Based on the results of analysis, we proposed a method of getting the best detection of Doppler spread by adaptive thresholding and a method of eliminating the partial aliasing of PSD by linear in...

Synovial vascularization in metacarpophalangeal joints of a patient with rheumatoid arthritis treated with leukocytapheresis (LCAP) was evaluated by Doppler sonography. After the treatment with LCAP, evaluation with American College of Rheumatology core set showed improvement, and the levels of C-reactive protein and serum amyloid A protein decreased. Power Doppler sonography demonstrated a red...

Pulsed wave Doppler ultrasound has been used for estimation of blood velocity in human body as an implicit result of being non-invasive method. In this research, to compensate the drawbacks such as long observation window of prevalent methods in the Doppler ultrasound, we proposed a new adaptive method based on projection of the cross spectral metric technique into the amplitude and phase estim...

In this study, the effects of non-sidelooking airborne radar clutter dispersion on space-time adaptive processing (STAP) is considered, and an efficient adaptive angle-Doppler compensation (EAADC) approach is proposed to improve the clutter suppression performance. In order to reduce the computational complexity, the reduced-dimension sparse reconstruction (RDSR) technique is introduced into th...

T e incorporation of color Doppler systems on trans\'aginal probes has made it possible to evaluate the normally occurring cyclical haemodynamic changes in the I"male pelvis. In addition to the depiction of major \ascularchannels, small intraparenchymal vessels within the uterus and ovaries can be easily demonstrated. While color flo\\ imaging improves the ability to demonstrate \ascular struct...

Doppler spectra, collected from a vertically pointing radar, are a measure of spectral reflectivity per interval of Doppler velocity. Ideally, the velocity interval can be converted to an equivalent drop size interval via an appropriate size versus velocity relationship. Since radar backscatter from a population of drops depends on the size and number density of the drops, and the size interval...

We demonstrate electromagnetically induced transparency in a four-level cascade system where the upper level is a Rydberg state. The observed spectral features are sub-Doppler and can be enhanced due to the compensation of Doppler shifts with AC Stark shifts. A theoretical description of the system is developed that agrees well with the experimental results, and an expression for the optimum pa...

BACKGROUND Echocardiographic measurements of left ventricular (LV) myocardial displacement may produce different results depending on the choice of employed modality and subjective adjustments during data acquisition and analysis. METHODS In this study, left ventricular longitudinal systolic displacement was quantified in 57 patients (31 women and 26 men, 50 +/- 16 years) using colour (colour...