Một trong những lợi ích liều 1,5 ml / kg là trong trường hợp của một viên thức ăn bị mất hoặc cần một số khác cho chính quyền tương phản bổ sung (ví dụ, opacification một mạch độc lập, chẳng hạn như mạch chủ tĩnh mạch động mạch phổi bên trái), | 422 FRUSH istration is high 2 mL s and the larger detector row 16-64 scanners are used. One of the benefits of mL kg dose is that in the event of a missed bolus or some other need for additional contrast administration ie opacification of an independent circuit such as the inferior vena cava to the left pulmonary artery a second dose of up to mL kg can be used. This is certainly lower than the recommended limits for routine angiography of 5 to 6 mL kg 5 . Rate of administration Rates of administration through various angio-catheters can be found in Table 1. For most children under about 12 years of age 2 mL s is an acceptable rate. Certainly if a larger-gauge angiocatheter eg 20 gauge in a relatively large 10- or 11-year-old child is available then rates of 3 to 4 mL kg are an option. It should be remembered that these faster rates of administration can result in a more unpleasant and frightening experience for the child. If a child is somewhat tenuously cooperative this may effect breathholding or cause movement which affects image quality. Route and technique of administration The route of administration can be either through a peripheral angiocatheter or central venous catheter. Peripherally inserted central venous catheters do not afford sufficient rates of injection to be useful for pediatric CT angiography. In addition I do not use butterfly needles because of the potential for vessel or other soft tissue injury with movement and the lack of sufficient access should additional IV administration be necessary. Injection can be either by manual hand or power injection. Power injection is always preferred given the consistency of contrast flow. Adequate CT angiography can be performed however with manual administration. In this institution manual administration is reserved for angiocatheters that are in hand or feet or which have tenuous or absent blood return. I also use manual injection with central venous catheters although data support that Table 1 .
