Use of modulated excitation signals in medical ultrasound. Part II: Design and performance for medical imaging applications

Misaridis, T; Jensen, JA

dc.contributor.author	Misaridis, T	en
dc.contributor.author	Jensen, JA	en
dc.date.accessioned	2014-03-01T01:23:18Z
dc.date.available	2014-03-01T01:23:18Z
dc.date.issued	2005	en
dc.identifier.issn	0885-3010	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16896
dc.subject.classification	Acoustics	en
dc.subject.classification	Engineering, Electrical & Electronic	en
dc.subject.other	Bandwidth	en
dc.subject.other	Computer simulation	en
dc.subject.other	Frequencies	en
dc.subject.other	Impulse response	en
dc.subject.other	Medical imaging	en
dc.subject.other	Signal processing	en
dc.subject.other	Signal to noise ratio	en
dc.subject.other	Spectrum analysis	en
dc.subject.other	Frequency modulated (FM) signals	en
dc.subject.other	Image contrast	en
dc.subject.other	Time bandwidth (TB)	en
dc.subject.other	Ultrasound systems	en
dc.subject.other	Ultrasonics	en
dc.title	Use of modulated excitation signals in medical ultrasound. Part II: Design and performance for medical imaging applications	en
heal.type	journalArticle	en
heal.identifier.primary	10.1109/TUFFC.2005.1406546	en
heal.identifier.secondary	http://dx.doi.org/10.1109/TUFFC.2005.1406546	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	In the first paper, the superiority of linear FM signals was shown in terms of signal-to-noise ratio and robustness to tissue attenuation. This second paper in the series of three papers on the application of coded excitation signals in medical ultrasound presents design methods of linear FM signals and mismatched filters, in order to meet the higher demands on resolution in ultrasound imaging. It is shown that for the small time-bandwidth (TB) products available in ultrasound, the rectangular spectrum approximation is not valid, which reduces the effectiveness of weighting. Additionally, the distant range sidelobes are associated with the ripples of the spectrum amplitude and, thus, cannot be removed by weighting. Ripple reduction is achieved through amplitude or phase predistortion of the transmitted signals. Mismatched filters are designed to efficiently use the available bandwidth and at the same time to be insensitive to the transducer's impulse response. With these techniques, temporal sidelobes are kept below 60 to 100 dB, image contrast is improved by reducing the energy within the sidelobe region, and axial resolution is preserved. The method is evaluated first for resolution performance and axial sidelobes through simulations with the program Field II. A coded excitation ultrasound imaging system based on a commercial scanner and a 4 MHz probe driven by coded sequences is presented and used for the clinical evaluation of the coded excitation/compression scheme. The clinical images show a significant improvement in penetration depth and contrast, while they preserve both axial and lateral resolution. At the maximum acquisition depth of 15 cm, there is an improvement of more than 10 dB in, the signal-to-noise ratio of the images. The paper also presents acquired images, using complementary Golay codes, that show the deleterious effects of attenuation on binary codes when processed with a matched filter, also confirmed by presented simulated images. © 2005 IEEE.	en
heal.publisher	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC	en
heal.journalName	IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control	en
dc.identifier.doi	10.1109/TUFFC.2005.1406546	en
dc.identifier.isi	ISI:000227598700005	en
dc.identifier.volume	52	en
dc.identifier.issue	2	en
dc.identifier.spage	192	en
dc.identifier.epage	206	en