TY - JOUR AU - Xu, H X; Liu, G J; Lu, M D TI - Characterization of focal liver lesions using contrast-enhanced sonography with a low mechanical index mode and a sulfur hexafluoride-filled microbubble contrast agent JO - J Clin Ultrasound VL - 34 PY - 2006 DO - 10.1002/jcu.20234 SP - 261 EP - 272 N1 - et al. ER -