Aid and Trade

Wholesale Price:     $347.00

We experimented with MR compatible contrast injectors and have not found them to be very useful. Injectors are extremely useful in CT and conventional X-ray angiography so that technologists and radiologists do not have to be in the room during X-irradiation of the patient. It adds an element of complexity to the injection process for the benefit of reducing radiation exposure to personnel. With CT, large volumes of iodinated contrast need to be injected at high rates, which could be difficult to do by hand. But in MRI, just like with ultrasound, there is no risk from being in the room during scanning. Furthermore, the relatively smaller volume of dynamic gadolinium contrast injections is easy to manage by hand injection. The Fourier nature of 3D spoiled gradient echo MRA data acquisition does not require the constant, precise injection rate that is essential for CT and X-ray angiography. Three-dimensional MRA is acquired with a single center of k-space that determines image contrast for the entire volume of data. Timing with respect to the center of k-space is more important than having a constant, mechanically controlled injection rate. Actually we not only found that injectors were not necessary, in many ways they were not as good as injecting by hand. Injecting by hand made it easier to identify problems with the iv. Especially when using a tenuous I.V. in the hand or wrist we were much more comfortable with hand injection. Power injectors tended to destroy the tenuous I.V. while with hand injection, the operator discovers the problem in time to salvage the iv and avoid wasting gadolinium. For patients with PICC or central lines or for pediatric patients, use of power injectors is forbidden because they can explode central lines and damage delicate pediatric veins. Also, standing next to the patient to perform hand injections made it a lot easier to give the patient hyperventilation and breath holding instructions. In fact, the whole process of coordinating contrast infusion, breath holding and activation of the scanner was much easier standing next to the magnet with hand injection than from outside the magnet using the power injector. For these reasons, our power injector sits idle in the corner of the room. The rare times when we actually use our power injector are for research projects when we want to have a mechanically precise injection rate for experimental purposes. Benefits: No delays switching from contrast infusion to saline flush. Stronger tubing resists kinking. Minimal tubing resistance. Twist lock connectors prevent accidental disconnections prone to std. connectors.