Image-Guided Fine-Needle Aspiration Cytology

Abstract

Several factors make image guidance necessary in fine-needle aspiration cytology (FNAC): A lesion is diffuse and difficult to palpate; the cytologist requires it for all deep-seated nonpalpable lesions; there may be sampling issues in a nonhomogeneous lesion with areas of different tissue characteristics (e.g., necrosis versus viable tumor or purely fatty areas versus contrast-enhancing areas in liposarcomas); and/or the lesion may be inaccessible behind bony structures or located inside bone. In many cases, the cytologist may simply prefer to use image guidance for a more exact needle placement. In all cases, however, the first step should be a thorough and careful review of all pertinent imaging studies to select the appropriate guiding modality, evaluate all possible access routes, and select appropriate needles and devices to reach the lesion. At this stage, the patient should also be considered: Is there coagulopathy or is the patient on an anticoagulant, antiplatelet, or thrombolytic medication? Are there any other absolute or relative contraindications to the procedure or to any imaging modality (e.g., magnetic resonance imaging [MRI])? If needed, the coagulant status should be corrected to acceptable levels.