ABSTRACT
In this chapter, we discuss basic techniques used in the neurointerventional suite and review many devices available to the interventional neuroradiologist. Unfortunately, the sizes of these devices are described in many different units of measurement. Catheters are described in French (Fr), wires are described in inches (¢¢), needles are described in gauge (G), and vessel diameter commonly is measured in millimeters (mm). When determining which instruments to use for an intervention, it is essential to keep in mind that 3-Fr = 1mm = 0.039¢¢, where larger values are used to describe a larger instrument. Gauge describes the outer diameter (O.D.) of a needle, while the inner diameter (I.D.) varies among manufacturers. Unlike the other three units just described, larger caliber needles are described with increasingly lower gauge number (e.g., a 19-G needle has a larger O.D. than a 21-G needle).
