Imaging features of intraductal papillary neoplasm of bile duct (IPN-B) on baseline ultrasound and contrast-enhanced ultrasound / 中华超声影像学杂志

ABSTRACT

Objective To investigate the features of intraductal papillary neoplasm of the bile duct (IPN-B) on baseline ultrasound and contrast-enhanced ultrasound (CEUS).Methods A retrospective analysis of the baseline ultrasound and CEUS in nine pathologically proven IPN-B lesions in eight patients.CEUS was performed with low mechanical index and continuous real-time imaging technique and the contrast agent of SonoVue.Results On conventional ultrasound,5 lesions were appeared as expansion of bile duct type,whose main features were cauliflower shape tumor (n =1) or papillary nodes (n =3) in expanded bile duct with rare blood supply;the other 3 lesions were appeared as complex cystic type,which contained cystic and solid components in the lesions.Many tiny anechoic areas were observed inside the solid lesions.Two lesions were rich in blood supply and another one was rare.All were communicated with adjacent slightly dilated bile duct.On CEUS,solid components of eight lesions appeared homogeneous (n =5) or heterogeneous (n =3) hyper-enhancement in the arterial phase and declined into hypo-enhancement in the portal and late phases.One lesion,on the contrary,was invisible on both conventional ultrasound and CEUS.Conclusions Understanding the ultrasound features of IPN-B is mandatory because of its low preoperative diagnosis rate on CEUS.IPN-B should be taken into consideration when cauliflower shape tumors or papillary nodules in expanded bile duct,as well as hyper-enhancement in the arterial phase and hypo-enhancement in the portal and late phases on CEUS,were demonstrated.