. Author manuscript; available in PMC: 2014 May 19.
Published in final edited form as: Ultrasound Med Biol. 2011 Aug;37(8):1240–1251. doi: 10.1016/j.ultrasmedbio.2011.05.011
© 2011 Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology.