Coaxial needle system of MR- and CT-guided aspiration cytology.

The use of aspiration cytology guided by imaging devices such as ultrasound, CT, or magnetic resonance (MR) has revolutionized the evaluation of disease processes throughout the body. Previously described coaxial needle systems for interventional procedures have a variety of limitations that are particularly problematic for use in the head and neck, CNS, and other areas where critical and complex anatomy is present in a very small region. We describe a new coaxial needle system for CT- and MR-guided aspiration cytology that overcomes these limitations.