Intravenous sedation and local anesthesia are generally used for percutaneous biopsy, but in some cases general anesthesia is required. Once the lesion is identified under ultrasound, CT or MR imaging, anesthesia is generally administered.
Generally, biopsies can be performed using multiple punctures or by using a coaxial system. With a coaxial system, an introducer needle is positioned at the biopsy site. Without a coaxial system, the needle tip is positioned at the proximal edge of the region to be sampled.
Laser-etched markings along the cannula are intended to provide visual confirmation of depth of penetration. An echogenic cannula tip may enhance sonographic imaging.
The needle is introduced through the cannula until the handle is flush with the hub. Single-handed operation is possible when a thumb action controls cocking, firing and sample retrieval. A precision-ground, electropolished stylet and cutting-cannula are designed to provide the sharpness required to obtain a clean, uncrushed specimen. Repositioning the cannula allows for subsequent samples to be obtained.
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