Image guided biopsy, performed for lesions seen mammographically.
A stereotactic core biopsy is an image guided procedure, where a mammographically detected lesion can be sampled. This is a minimally invasive method, to obtain a tissue diagnosis. This type of biopsy is done most often for calcifications, seen on a mammogram. These mammographic findings are typically not palpable (cannot be felt on physical exam), so, biopsy will require image guidance. The procedure is most typically performed in the Breast Imaging Department, rather than the office.
During this procedure, the patient is in the prone position (face down). The breast is then placed through an aperture found in the biopsy table. The breast is then placed within compression, while a mammogram is performed. The lesion in questions is then identified, and sophisticated computer generated coordinates are determined. These coordinates are then entered into the biopsy instrument, so as to guided the needle to the proper location. The radiologist will numb the skin and tissues within the breast, along the anticipated course of the biopsy needle. A small skin incision is made, and, under direct mammographic guidance, the needles is placed to the site of the abnormality. The typical biopsy needle is vacuum assisted. This means that multiple biopsies can be taken, without having to re-insert the needle each time. Once positioned, the procedure typically takes only 20 minutes. The removed tissue is imaged, with a mammogram, to assure that the area in question has been properly sampled.
Following the biopsy (as is the case with all core needle biopsies), a small titanium clip is placed at biopsy site. The purpose of this marker, which is visible mammographically, is to mark the site where the biopsy was done. This serves many purposes: (1) allows the area of concerned to be followed radiographically; (2) allows the confirmation that the correct site has been biopsied; (3) marks the site for excision, should the biopsy result require surgical intervention. The clip is made of an inert substance, so, the risk of allergy is next to zero.