Rapid spectroscopic velocity quantification using periodically oscillating gradients
| Autor: | Florian Fidler, Peter M. Jakob, Constanze Schelhorn |
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| Rok vydání: | 2012 |
| Předmět: |
Models
Molecular Physics Nuclear and High Energy Physics Magnetic Resonance Spectroscopy Field (physics) Spins business.industry Biophysics Condensed Matter Physics Biochemistry Spectral line Computational physics Optics Models Chemical Flow velocity Flow (mathematics) Oscillometry Spin echo Range (statistics) Group velocity Computer Simulation business Algorithms |
| Zdroj: | Journal of Magnetic Resonance. 214:175-183 |
| ISSN: | 1090-7807 |
| DOI: | 10.1016/j.jmr.2011.11.005 |
| Popis: | In this work two spectroscopic methods are described which allow rapid flow velocity quantification in the presence of a parabolic velocity distribution. This method requires only a single excitation and is based on flow encoding by periodically oscillating gradients. In the shown spin echo variant additional refocusing pulses correct for field inhomogeneities. A theoretical model is introduced, which describes the course of the derived spectra even in high flow region, where a significant part of the encoded spins leaves the sensitive area of the coil during data acquisition (outflow-effect). It was demonstrated that both methods can quantify flow velocities within the velocity range of 1 mm / s up to 36 cm / s in the presence of a parabolic flow velocity distribution. The maximum velocity of the parabolic distribution is indicated in this method by a peak in the acquired spectrum from which the velocity could be quantified. Flow velocity quantification by periodically oscillating gradients seems a reasonable and fast alternative to established imaging techniques. |
| Databáze: | OpenAIRE |
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