Which of the Following Statements About Vascular Sonography Is Untrue

Which of the following statements about vascular sonography is untrue?

A) Duplex sonograms are ordered to determine hemodynamic status of the vascular system and to detect the presence of pathology.
B) Vascular imaging is performed to determine the absence or presence of stenosis, aneurysm, thrombosis, or other pathologic conditions without ionizing radiation or contrast agents.
C) Ultrasound of the cerebrovascular system is not safe for pediatric patients.
D) The vascular sonographer must possess a detailed understanding of normal and abnormal blood flow patterns.