منابع مشابه
Transient response harmonic imaging: an ultrasound technique related to brain perfusion.
BACKGROUND AND PURPOSE Gray-scale harmonic imaging is the first method to visualize blood perfusion and capillary blood flow with ultrasound after intravenous contrast agent application. The purpose of the present study was to evaluate the potential of transient response second harmonic imaging (TRsHI) to assess normal echo contrast characteristics in different brain areas by transcranial ultra...
متن کاملAnalysis and Reduction of the Transient Response in SSFP Imaging
Introduction: Fully refocused steady-state free precession (SSFP) is a fast imaging sequence offering high SNR efficiency. Extensions to SSFP such as fluctuating equilibrium [l] and linear combination SSFP [2] enable water-fat separation and immunity to off-resonance. Because of the volatile transient response during the approach to steady state, data acquisition is usually delayed until this t...
متن کاملTissue harmonic imaging
Harmonics have much significance in music. A musical note has three characteristics. 1 Pitch (or frequency) 2 Loudness 3 Quality (or tone). Quality is the audible difference heard between two musical notes of the same pitch and loudness. Hence, a piano based C-note does not sound the same as a C-note played on a guitar, due to the existence of harmonic frequencies. The same note from various in...
متن کاملComparison of contrast-enhanced fundamental imaging, second-harmonic imaging, and pulse-inversion harmonic imaging.
RATIONALE AND OBJECTIVES To investigate the feasibility of recent contrast-specific ultrasound techniques in depicting vascular flow and the effects of changing the output power of the transducer and insonation mode on contrast enhancement, the authors performed an experimental study with a flow phantom. METHODS While changing the mechanical index and the sound insonation mode (continuous and...
متن کاملNumerical conversion of transient to harmonic response functions for linear viscoelastic materials.
Viscoelastic material behavior is often characterized using one of the three measurements: creep, stress-relaxation or dynamic sinusoidal tests. A two-stage numerical method was developed to allow representation of data from creep and stress-relaxation tests on the Fourier axis in the Laplace domain. The method assumes linear behavior and is theoretically applicable to any transient test which ...
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ژورنال
عنوان ژورنال: Stroke
سال: 1998
ISSN: 0039-2499,1524-4628
DOI: 10.1161/01.str.29.9.1901