Imaging of axillary lymph nodes.

There is increasing interest in the radiological diagnosis of axillary lymph nodes in patients with breast cancer, especially in the preoperative diagnosis of metastatic nodes. Both CT (computed tomography) and MRI (magnetic resonance imaging) are cross-sectional imaging methods that produce high-quality images of the axilla. MRI also uses contrast enhancement profile, for example in imaging of breast lesions. Few studies have been published on this subject, but the latest have shown high sensitivity and specificity (CT 93.8 and 82.1%, respectively; MRI 90 and 82%, respectively), although, both CT and MRI are restricted to imaging only. US (ultrasound) is widely spread and is fast and accurate with high resolution. Sensitivity and specificity vary (68.2-92% and 90-100%, respectively). Most importantly, there is the possibility of US-guided FNAB (fine-needle aspiration biopsy) of pathological nodes, which increases the specificity. Initial results with colour Doppler are promising, but a recent study has shown that the presence of colour Doppler flow signal is highly non-specific. Other parameters such as flow pattern and distribution may prove to be of value in this method. Today, the method of choice for the daily routine is US in conjunction with FNAB.