Percutaneous image-guided breast biopsy is less invasive, less expensive, and more efficient than diagnostic surgical biopsy.

• Sensitivity of ultrasound-guided breast core needle biopsy (CNB): 97–9%
  
• Fine-needle aspiration biopsy (FNAB) is less sensitive, but can be very useful in evaluating additional lesions or abnormal lymph nodes in the setting of a known primary breast cancer.
  
• Most breast masses are amenable to ultrasound-guided biopsy.

American College of Radiology (ACR) Practice Guidelines for performance of ultrasound-guided breast biopsy recommends that radiologists who are beginning to perform these procedures meet practice guidelines for performing breast ultrasound and obtain

• At least 3 hours of continuing professional education hours in breast ultrasound intervention, and perform at least three procedures under direct supervision. These training suggestions can be met in residency or fellowship training programs.
  
• In addition, the ACR recommends that radiologists perform at least 12 ultrasound-guided procedures annually to maintain skills.

Advantages of image-guided preoperative diagnosis of breast cancer over diagnostic surgical biopsy:

• Reduces the number of women undergoing surgical procedures
  
• Allows the patient and surgeon to discuss therapeutic options in advance of surgery
  
• Once a breast cancer has been diagnosed, the extent of disease can be evaluated by ultrasound or magnetic resonance imaging (MRI). Ultrasound-guided biopsy documenting multifocal or multicentric disease may alter surgical management.
  
  
  
  • Percutaneous biopsy of nonpalpable cancer results in a single therapeutic surgical operation in 81% of women. Receptor status as determined by CNB samples can also guide neoadjuvant chemotherapy if needed.

Other advantages of ultrasound guidance for breast CNB over stereotactic guidance include

• The lack of ionizing radiation is particularly important for pregnant women with a breast mass.
  
• Real-time visualization of the needle during biopsy improves confidence that a small lesion has been accurately sampled.
  
• The supine position of the patient for an ultrasoundguided procedure is often more comfortable than the prone or sitting position used for stereotactic procedures.
  
• Stereotactic biopsy is also limited by compressed breast thickness of at least 2.5 cm, whereas small breast thickness rarely affects the ability to perform ultrasound-guided breast biopsy.
  
• Ultrasound-guided breast biopsies (in experienced hands) are often more efficient than stereotactic biopsy.

Percutaneous image-guided biopsy has largely replaced diagnostic surgical biopsy in the evaluation of breast lesions in many practices. Most breast lesions that are visible on ultrasound that are suspicious (Breast Imaging Reporting and Data System [BI-RADS] assessment category 4) or malignant (BI-RADS 5) are amenable to ultrasoundguided core needle biopsy. Image-guided biopsy is not typically performed for

• Lesions with BI-RADS assessment category 3: Probably benign, unless there is undue patient anxiety or the reliability of the patient for return visit is uncertain, for example a homeless woman with limited healthcare resources.
  
• In the setting of a palpable finding, diagnostic ultrasound-guided biopsy can be an alternative to excision.

• Lesion was difficult to visualize for image-guided biopsy.
  
• Patient preference
  
• Lesion was superficial or very small.

• Can reduce the number of women undergoing sentinel lymph node biopsy.
  
• Women with a newly diagnosed invasive breast cancer undergo sentinel lymph node biopsy at the time of lumpectomy or mastectomy (unless there is palpable adenopathy).
  
• If FNA of an axillary lymph node in a woman with diagnosed breast cancer shows metastatic breast cancer, she can undergo axillary dissection at the first surgical procedure.
  
• If ultrasound shows normal axillary lymph nodes or the ultrasound-guided FNA or CNB is negative, sentinel node biopsy can be performed.

Contraindications to ultrasound-guided breast biopsy:

• Uncooperative patient during the procedure
  
  
  
  • Mild sedation using fast-acting oral agents can be helpful if necessary.
  
  
• An uncorrectable known bleeding disorder
  
  
  
  • For these women, FNA or surgical biopsy may be reasonable alternatives.

Women who are not good candidates for stereotactic biopsy due to stroke or small breast size can usually undergo ultrasound-guided breast biopsy if the lesion is identified. The presence of a breast implant can increase the complexity of the approach, but is not necessarily a contraindication.

• Use of 10 MHz or higher linear transducer is highly recommended.
  
• Focal zones should be adjustable rather than fixed in position.

Either automated throw needle (CNB) or vacuum-assisted (VAB) biopsy devices may be used for ultrasound-guided breast biopsy.

• 14-gauge needles are most commonly used for ultrasound-guided CNB, but range in size from 12–18 gauge.
  
• Higher diagnostic yields have been demonstrated for 14-gauge needles compared with 16- or 18-gauge core biopsy needles.

• Needle size ranges from 8–14 gauge.
  
• VAB devices may collect single samples that must be retrieved after each pass (similar to CNB devices) or may collect multiple samples with a single needle insertion.
  
• VAB is more advantageous for calcified lesions. Bleeding complications may be slightly higher with VAB devices than CNB devices.

VAB can be useful for selective cases:

• A small lesion that may be difficult to visualize after the first one or two samples. In these cases, the needle can be placed posterior to the lesion and kept stationary during the biopsy. The lesion can be observed for resolution during sampling under real-time.
  
• VAB is also useful for the uncommon case when calcifications are sampled by ultrasound rather than stereotactic-guidance as VAB devices that require only one needle insertion often result in less introduction of air that may obscure calcifications.

• The Radiologic Diagnostic Oncology Group V found the sensitivity and specificity of FNAB of nonpalpable breast lesions to be 85–88% and 56–90%, respectively, which is considerably lower than CNB.
  
• FNAB has lower sensitivity for invasive lobular carcinoma compared with invasive ductal carcinoma.
  
• CNB should be performed instead of FNAB for most breast lesions.

FNAB can be very useful in

• The evaluation of cystic lesions of the breast
  
• A complicated cyst or complex mass may initially undergo FNAB. If a residual solid component remains, CNB can then be performed.
  
• FNAB of suspicious axillary lymph nodes can circumvent the need for sentinel node biopsy in the setting of known breast cancer.

Prior to beginning the procedure, diagnostic breast imaging including any mammograms, ultrasound, and MR images should be reviewed.

• An examination table that is adjustable in height is convenient to accommodate for radiologist stature.
  
• A table that rotates is useful for radiologists who prefer to use their dominant hand to manage the biopsy device.
  
• Lights should be dim enough to visualize the lesion well on the ultrasound screen.