PMID- 17375821
OWN - NLM
STAT- MEDLINE
DCOM- 20070424
LR  - 20191210
IS  - 0885-3010 (Print)
IS  - 0885-3010 (Linking)
VI  - 54
IP  - 3
DP  - 2007 Mar
TI  - Contrast imaging with chirped excitation.
PG  - 520-9
AB  - Coded excitation has been successfully used in imaging to increase the 
      signal-to-noise ratio (SNR) and penetration depth. With a contrast agent, 
      wideband signals have been hypothesized to increase the contrast-to-tissue ratio 
      (CTR). However, nonlinear properties of contrast agents make decoding difficult 
      when applying coded excitation to contrast imaging. We propose two chirped 
      excitation methods to image contrast agents, with a mechanical index (MI) ranging 
      from 0.05 to 0.34. In the single chirp method, one chirp is transmitted, followed 
      by a clutter filter to reject tissue echoes, then a matched filter is used to 
      recover range resolution. In the chirp sequence method, an increasing and 
      decreasing chirp sequence is transmitted followed by subtraction of the 
      compressed echoes to reject tissue echoes (assuming tissue is a linear scatterer 
      at low MI). Ten independent acoustic experiments were performed to evaluate the 
      CTR for chirp and tone burst insonation, with the same spatial peak temporal 
      averaged intensity (I(SPTA)). A significant increase in CTR, ranging from 4 dB to 
      8 dB, is observed for chirped excitation as compared with tone burst insonation, 
      at an I(SPTA) of 0.1 and 0.3 mW/cm2 (P < or = 5e-3). To achieve the same CTR of 
      15 dB, the spatial peak pulse averaged intensity (I(SPPA)) can be decreased by 6 
      dB for chirp insonation as compared with tone burst insonation (P < 1e-5). 
      Additionally, an increase of more than 10 dB in tissue rejection ratio (TRR) is 
      observed for a chirp sequence insonation compared to tone burst phase inversion 
      for this set of parameters (P < or = 1e-9). Deconvolution of the linear 
      microbubble response from the received echoes is proposed as a method to recover 
      spatial resolution. The difference in the axial resolution resulting from chirp 
      and three-cycle tone burst insonation is approximately 220 microm. The difference 
      in the mainlobe width between experimental and predicted compressed echoes is 
      less than 20%. The side-lobe amplitude is 9 dB to 16 dB below the mainlobe with a 
      transmitted I(SPTA) from 0.1 to 6.6 mW/cm2.
FAU - Sun, Yang
AU  - Sun Y
AD  - Department of Biomedical Engineering, University of California Davis, Davis, CA 
      95616, USA. ywsun@ucdavis.edu
FAU - Kruse, Dustin E
AU  - Kruse DE
FAU - Ferrara, Katherine W
AU  - Ferrara KW
LA  - eng
GR  - R01 CA 112356/CA/NCI NIH HHS/United States
GR  - R01 CA 76062/CA/NCI NIH HHS/United States
PT  - Evaluation Study
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PL  - United States
TA  - IEEE Trans Ultrason Ferroelectr Freq Control
JT  - IEEE transactions on ultrasonics, ferroelectrics, and frequency control
JID - 9882735
RN  - 0 (Contrast Media)
SB  - IM
MH  - *Algorithms
MH  - *Contrast Media
MH  - Image Enhancement/*methods
MH  - Image Interpretation, Computer-Assisted/*methods
MH  - *Microbubbles
MH  - Phantoms, Imaging
MH  - Reproducibility of Results
MH  - Sensitivity and Specificity
MH  - *Signal Processing, Computer-Assisted
MH  - Ultrasonography/instrumentation/*methods
EDAT- 2007/03/23 09:00
MHDA- 2007/04/25 09:00
CRDT- 2007/03/23 09:00
PHST- 2007/03/23 09:00 [pubmed]
PHST- 2007/04/25 09:00 [medline]
PHST- 2007/03/23 09:00 [entrez]
AID - 10.1109/tuffc.2007.275 [doi]
PST - ppublish
SO  - IEEE Trans Ultrason Ferroelectr Freq Control. 2007 Mar;54(3):520-9. doi: 
      10.1109/tuffc.2007.275.