A cotton ball soaked in heparinized saline is used to lubricate the guidewire before it is placed into the target blood artery along with a guiding catheter as directed. In order to get rid of air bubbles around the ultrasonic transducer, further flushing is typically performed. The imaging catheter's Guidewires rail is placed via the guiding catheter, and the guidewire is threaded through the rail. Then, with the imaging catheter momentarily halted in the guiding catheter, an IVUS test image with sensor rotation is evaluated. After stopping sensor rotation, the imaging catheter is reinserted. The depth indicators on the catheter sheath are used to calculate the insertion distance prior to fluoroscopy. On a monitor, the operator follows the marker close to the imaging catheter's tip.
