cdfi is an acronym that stands for blood flow signal. During a breast ultrasound, the blood flow supply is described in terms of the breast tissue, breast nodule or lump, and whether there is a blood flow signal around or within the lump. It is a criterion for determining the benign or malignant nature. If there is an abundant supply of blood flow, it suggests a higher likelihood of malignancy. If there is no or little blood flow signal, it suggests a higher likelihood of benign. This is only a hint of the imaging examination, can not be used as the only criterion to determine the benign and malignant, the diagnosis needs to be confirmed by puncture needle biopsy or direct surgical resection, to clarify the diagnosis.