Fig. 1

Gadobutrol bolus infusion setup. a Intravenous (IV) extension tubing is connected between the end of the injector line and the IV connected to the patient; either 2 pieces (if patient is ≤50 kg) or 3 pieces (if patient is >50 kg). This provides 5 or 7.5 mL of IV tubing volume between the injector and the patient, respectively. A three-way stopcock is attached between the injector and extension tubing. Both pumps of the power injector are loaded with saline. b When the patient is ready for time-resolved MRA, the technician turns the stopcock off to the injector, and 0.1 mL/kg undiluted gadobutrol is infused into the extension tubing. The power injector is set for pump A to inject 10 mL at 2 mL/s, and pump B is set to inject 20 mL/s at 2 mL/s. The stopcock is then turned back to allow flow from injector to patient. c Injection is then started at the appropriate time, and thus the contrast in the tubing is injected into the patient