What techniques can help to increase the conspicuity of a needle during a Ultrasound guided procedure?
There are several very helpful techniques that may improve visualization of the needle during deep US-guided procedures where the needle angle is steep in order to reach the target. The first is the jiggle technique, during which the operator moves the needle minimally forward and backward along the needle path. This motion results in movement/vibration of the adjacent soft tissues, which often discloses the needle location. The needle is not advanced or moved side to side during this maneuver, just minimally pulsed to and fro. One may also rotate the needle, as the bevel is often more echogenic appearing. Hydrodissection refers to injecting a small amount of fluid, which not only aids in confirming needle tip position with a small anechoic pocket of fluid, but also opens up a space between anatomic structures, resulting in an obstacle-free path for further needle adjustments. Special US settings/features such as beam steering and virtual convex imaging also significantly increase the conspicuity of the needle. However, the most important technique for improving visualization of the needle is to keep the needle as perpendicular to the sound beam, or as parallel to the transducer footprint, as possible. This may be accomplished by moving the puncture site farther from the transducer, performing the procedure along the curvature of an extremity, or using the transducer to deform the soft tissues with a heel-toe maneuver.