TY  - CHAP
M1  - Book, Section
TI  - Chapter 50. Introduction to Ultrasound-Assisted Regional Anesthesia Techniques
A1  - Gray, Andrew T.
A2  - Hadzic, Admir
Y1  - 2007
N1  - 
T2  - NYSORA Textbook of Regional Anesthesia and Acute Pain Management
AB  - Ultrasound  imaging  utilizes  high-frequency  sound  waves  (3–17  MHz).  Because  the  speed  of  sound  in  soft  tissue  is  fairly  constant  (1540  m/sec),  the  position  of  objects  can  be  inferred  from  the  time  of  flight  of  their  received  echoes.  The  product  of  wavelength  and  frequency  is  the  speed  of  sound,  so  high-frequency  sound  waves  have  shorter  wavelengths,  and  therefore  provide  better  axial  resolution.  Attenuation  of  sound  waves  is  frequency-dependent  (approximately  0.75  dB/cm/MHz),  so  penetration  of  high-frequency  sound  waves  into  deep  tissue  is  limited.  For  interventional  guidance,  one  of  the  biggest  advantages  of  ultrasound  over  other  imaging  modalities  is  the  real-time  acquisition  of  images.  Frame  rates  of  30  Hz  or  higher  are  common  in  clinical  practice.  
SN  - 
PB  - The McGraw-Hill Companies
CY  - New York, NY
Y2  - 2024/04/19
UR  - accessanesthesiology.mhmedical.com/content.aspx?aid=3504552
ER  -