 A noninvasive assessment of hepatic fibrosis is desperately needed to advance the care of children with CF significant liver disease and to provide for measurements during clinical trials. That global assessment might serve as both a predictordescriptor of disease course but also as a critical biomarker for clinical research. FibroScan measurement of liver stiffness has great potential to fill this void. The underlying hypothesis of this proposal is that elastography in addition to US can improved the prediction of the development of a nodular liver on US and development of portal hypertension over time in children and young adults with CF. 