TAILIEUCHUNG - Tissue harmonic imaging with coded excitationa

It becomes more important to obtain medical ultrasound images with higher signal-to-noise ratio (SNR) and higher spatial resolution. In the last decade, tissue harmonic imaging (THI) and coded excitation to medical ultrasound imaging have been investigated. | 6 Tissue Harmonic Imaging with Coded Excitation Masayuki Tanabe1 2 Takuya Yamamura2 Kan Okubo2 and Norio Tagawa2 1JSPS Research Fellow 2Graduate School of System Design Tokyo Metropolitan University Japan 1. Introduction It becomes more important to obtain medical ultrasound images with higher signal-to-noise ratio SNR and higher spatial resolution. In the last decade tissue harmonic imaging THI and coded excitation to medical ultrasound imaging have been investigated. Coded excitation can overcome the trade-off between spatial resolution and penetration which occurs when using the conventional pulse Chiao 2005 Hu et al. 2001 Tanabe et al. 2008 . It is said that chirp signal is the most robust code for medical ultrasound image Misaridis Jensen 2005 . THI can acquire higher spatial resolution image and has been used in the commercial medical ultrasound system. A combination of coded excitation and THI coded THI has been investigated Arshadi et al. 2007 Hu et al. 2001 Song et al. 2010 Tanabe et al. 2010 . As a problem of THI the frequency bandwidths of the fundamental and the harmonic components often overlap. The spectral overlap causes degradation of spatial resolution and the undesirable artifact. For the solution to the problem only the harmonic component is extracted by pulse inversion PI method. However if reflectors in the region of interest ROI move even a little the fundamental components of echos are not cancelled completely. The intensity of the extracted harmonic components is still much smaller than the intensity of the residual fundamental component. Hence the residual fundamental component has a bad effect on THI. In sections II through IV THI coded excitation and the combination of them are explained. In section V we propose a new method which can extract broader bandwidth of the harmonic component for coded THI. The feasibility of the method is evaluated with experiments and simulations and the expected performance in term of axial resolution and SNR

• Y khoa - Dược
• Tissue harmonic imaging
• Imaging with coded excitationa
• Coded excitation
• Degradation of spatial resolution
• The extracted harmonic components
• BMC Cancer
• Collagen organization
• Renal cell carcinoma
• Tumor grading
• Second harmonic generation imaging
• Tissue microarray