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Investigations of spectral resolution and angle dependency in a 2-D tracking Doppler method

, : Investigations of spectral resolution and angle dependency in a 2-D tracking Doppler method. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 61(7): 1161-1170

An important source of error in velocity measurements from conventional pulsed wave (PW) Doppler is the angle used for velocity calibration. Because there are great uncertainties and interobserver variability in the methods used for Doppler angle correction in the clinic today, it is desirable to develop new and more robust methods. In this work, we have investigated how a previously presented method, 2-D tracking Doppler, depends on the tracking angle. A signal model was further developed to include tracking along any angle, providing velocity spectra which showed good agreement with both experimental data and simulations. The full-width at half-maximum (FWHM) bandwidth and the peak value of predicted power spectra were calculated for varying tracking angles. It was shown that the spectra have lowest bandwidth and maximum power when the tracking angle is equal to the beam-to-flow angle. This may facilitate new techniques for velocity calibration, e.g., by manually adjusting the tracking angle, while observing the effect on the spectral display. An in vitro study was performed in which the Doppler angles were predicted by the minimum FWHM and the maximum power of the 2-D tracking Doppler spectra for 3 different flow angles. The estimated Doppler angles had an overall error of 0.24° ± 0.75° when using the minimum FWHM. With an in vivo example, it was demonstrated that the 2-D tracking Doppler method is suited for measurements in a patient with carotid stenosis.


PMID: 24960705

DOI: 10.1109/TUFFC.2014.3015

Other references

Bronner, F.; Yost, J.H., 1985: Saturable and nonsaturable copper and calcium transport in mouse duodenum. Duodenal copper and calcium absorption was evaluated in 30-day-old normal male Swiss mice by an in situ loop procedure. For both ions, the 90-min absorption values yielded a curve that was resolvable into a hyperbolic (saturable) and a linear (non...

Lieflander, Manfred, 1963: The reaction of carbonate-hydro-lyase in heavy water. The rate of the enzymic hydration of CO2, catalysed by carbonate hydro-lyase, is lower in D2O than in H2O, while the respective rates of the reverse reaction are the same. The enzyme is therefore not inactivated. Base catalysis by imidazole residu...

Hansen, T.W.; Allen, J.W., 2000: Bilirubin oxidation by brain mitochondrial membranes is not affected by hyperosmolality. Brain mitochondrial membranes oxidize bilirubin at a rate that may be biologically significant. Hyperosmolality delays clearance of bilirubin from rat brain. We hypothesized that this might be due to a decrease in brain bilirubin metabolism. Rats...

Maffia, M.; Rizzello, A.; Acierno, R.; Rollo, M.; Chiloiro, R.; Storelli, C., 2002: Carbonic anhydrase activity in tissues of the icefish Chionodraco hamatus and of the red-blooded teleosts Trematomus bernacchii and Anguilla anguilla. Carbonic anhydrase (CA) activity was measured in blood, intestine, kidney and gill of two Antarctic teleosts, the haemoglobinless Chionodraco hamatus and the red-blooded Trematomus bernacchii, and of the temperate teleost Anguilla anguilla. In all...

Daessle L.W.; Carriquiry J.D.; Navarro R.; Villaescusa Celaya J.A., 2000: Geochemistry of surficial sediments from Sebastian Vizcaino Bay, Baja California. Thirty-seven surficial sediment samples from Vizcaino Bay, Baja California, are analysed for their phosphate, organic matter, carbonate, as well as metal contents (Al, Fe, Mn, Zn, Cu, Ni, Cr, Cd and Sr). Highest organic carbon concentrations (up t...

Lopatin, D.E.; Voss, E.W., 1974: Anti-lysergyl antibody: measurement of binding parameters in IgG fractions. Immunochemistry 11(6): 285-293

Richardson, Harriet., 1912: Note on an isopod name. Proceedings of the Biological Society of Washington, 25 188

Paivarinta H.; Eranko O., 1982: Number of neurons and dexamethasone induced small intensely fluorescent cells in developing sympathetic ganglia and in intra ocular ganglion transplants. Daily dexamethasone (DM) injections to newborn rats caused in a week an increase in the number of small intensely fluorescent (SIF) cells in the superior cervical ganglion to a value 9 times that in the ganglia of saline-treated controls. The numb...

BALGOZHINA.S.Zh., 1963: Myeloblastic Attacks In Chronic Myeloleukosis And Their Treatment. Terapevticheskii Arkhiv 35: 97-101

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