Introduction

Significant improvements in both imaging modalities and biopsy devices have occurred in the past two decades, which have changed the standard care pathways in breast diagnosis. Vastly improved near-field ultrasound equipment, digital mammography, and breast MRI now allow for much better visualization of the breast tissue and any abnormality within. Surgical biopsy for diagnosis has been supplanted by minimally invasive tissue acquisition techniques. Image-guided fine-needle aspiration (FNA) has been replaced by histologic methods beginning in the 1980s with automated large-core biopsies. Subsequent improvements in tissue acquisition have been realized with vacuum-assisted biopsies (VABs) with their inherent ability to remove most, if not all, of the visualized lesion. These improvements have in turn raised the possibility of percutaneous or minimally invasive therapy.

Manufacturers of ultrasound equipment have realized the importance of breast-specific hardware and software. High-frequency, broadband width transducers (up to 17 MHz) have allowed for exquisite resolution of very small structures within the breast and the detection of subcentimeter cancer as well as ductal carcinoma in situ (DCIS) (Fig. 10-1). Coded harmonics and spatial compound imaging techniques reduce artifacts and allow for more confident lesion visualization. Color Doppler flow can be used in the setting of complex cysts and intraductal lesions to detect blood flow (Fig. 10-2). All these improvements have brought breast ultrasound to a level which makes it an indispensable tool in breast diagnosis.

Figure 10-1 Biopsy-proven ductal carcinoma in situ (DCIS) as found at targeted second-look ultrasound after diagnostic breast MRI in patient with recent diagnosis of breast cancer.

Figure 10-2 Complex cystic and solid mass with color Doppler flow proof of intracystic mass. Biopsy-proven papilloma with atypia.

Stereotactic mammographic units have digital imaging, which provides superior contrast resolution and near instantaneous image display compared with film screen imaging (Fig. 10-3). This has improved both efficiency and accuracy of the biopsy procedures. In addition, many manufacturers now offer digital mammographic spot-imaging capabilities. There are also units designed exclusively for specimen radiography (Fig. 10-4). These devices allow for immediate evaluation of breast tissue for the presence of calcifications and post-biopsy metallic markers, thus speeding the performance of both stereotactic biopsies as well as surgical lumpectomies. Finally, several manufacturers now have full-field digital mammography, which provides superior contrast resolution, increased throughput, and reduced radiation exposure compared with standard film screening mammography (Fig. 10-5). Full-field digital has also been shown to be superior to film screen for women with dense breasts, premenopausal women, and women under 50 years old.¹

Figure 10-3 Mammo Test Stereotactic Biopsy Table.

(Courtesy of Fischer Imaging, Inc. Denver, Colorado.)

Figure 10-4 DX 50 Core Specimen Radiography System.

(Courtesy of Faxitron X-Ray, Lincolnshire, Illinois.)

Figure 10-5 Selenia Digital Mammography.

(Courtesy of Lorad, a Hologic Company, Bedford, Massachusetts.)

Breast MRI, though expensive, is an exceptionally helpful tool in treatment planning. There are in general two types of breast MRI, both of which use gadolinium contrast injection: dynamic breast MRI and high-resolution breast MRI (Fig. 10-6A through C). Dynamic breast MRI images the breast multiple times in the first few minutes after contrast injection. This allows for analysis of contrast uptake and washout with an improved specificity compared with the high-resolution breast MRI. High-resolution breast MRI results in very high sensitivity with impressive spatial resolution. The specificity is not as high as with dynamic imaging, however.^2,³ Most modern breast MRI equipment and software can do both dynamic and high-resolution imaging while imaging both breasts simultaneously.

Figure 10-6 A, Spiculated biopsy-proven invasive ductal carcinoma (IDC). B, Color map overlay of washout pattern of enhancement in IDC. C, Slope image-dynamic representation of suspicious pattern of enhancement—washout pattern.

Our experience has been that the increased specificity associated with dynamic imaging is not sufficient to eliminate the need for biopsy in enhancing lesions (Fig. 10-7A and B). However, in the patient with multiple enhancing nodules with benign morphology or diffuse fibroglandular enhancement, the dynamic information may assist in identifying the more suspicious lesion(s) to target. We rely heavily on the morphologic characteristics gleaned from the high-resolution images (Fig. 10-8A through D). We have found that MRI is most useful in the preoperative assessment of a patient with a biopsy-proven breast carcinoma.⁴^–⁷ In these instances, the true extent of disease is much better appreciated than with standard mammographic images, and the surgery can be appropri ately tailored. In addition, in approximately 5% to 7% of patients, otherwise unsuspected carcinoma is detected in a different quadrant of the same breast (multicentric disease) (Fig. 10-9A and B). Also, in approximately 5% to 7% of patients, otherwise unsuspected carcinoma is found in the opposite breast⁸^–¹⁰ (Fig. 10-10A and B). More frequently, we are performing breast MRI on high-risk patients. These include patients with BRAC 1 and BRAC 2 genetic risk and patients with previous high-risk biopsy results or previous breast cancer¹¹^–¹⁶ (Fig 10-11A through C). Occasionally, MRI is used for monitoring regression of disease during neoadjuvant chemotherapy. Other uses include postlumpectomy margin assessment^17,¹⁸ and evaluating patients with adenocarcinoma of an axillary node and an unknown primary.¹⁹

Figure 10-7 A, Sagittal breast MRI of known invasive ductal carcinoma at minimally invasive ultrasound-guided biopsy. B, Known cancer demonstrates blue/continuous pattern of dynamic enhancement.

Figure 10-8 Atypical papilloma in the 6 SA location. Separate enhancing masslike lesion in the upper outer quadrant has slightly irregular margins and is an invasive ductal carcinoma (IDC) at targeted ultrasound-guided biopsy. A, IDC at 2:00 location. B, Color map applied to IDC at 2:00 location. C, Different patient with MRI image of classic IDC. D, MRI image with color map applied to IDC.

Figure 10-9 Unsuspected multifocal and multicentric breast cancer. A, Biopsied invasive ductal carcinoma (IDC) at 6:00 with targeted ultrasound biopsy-proven high nuclear grade ductal carcinoma in situ (DCIS) extending toward the nipple. B, Unsuspected small IDC with DCIS in upper outer quadrant identified with MRI and proven with targeted ultrasound-guided biopsy.

Figure 10-10 A, Known right breast invasive ductal carcinoma (IDC), sagittal MRI image. B, Unsuspected left intermediate nuclear grade ductal carcinoma in situ, identified and biopsied with targeted breast ultrasound, sagittal MRI subtraction image.

Figure 10-11 A, Mammogram of patient with extremely strong family history of breast cancer, including two sisters and a maternal aunt. BRCA analysis was negative. Dense breast tissue was found on mammography with no focal abnormality. B, Screening breast MRI demonstrates spiculated enhancing mass in the upper inner quadrant of the left breast, sagittal view. C, MRI axial view. Targeted breast ultrasound and ultrasound-guided biopsy demonstrating an invasive ductal carcinoma.

Two main issues must be decided in any minimally invasive breast biopsy: which guidance modality is to be used, and what needle is best suited for the lesion undergoing the biopsy. Of the three breast imaging modalities (ultrasound, stereotactic mammography, and MRI), we prefer ultrasound guidance in the majority of cases. Stereotactic guidance is reserved almost exclusively for targeting microcalcifications, and MRI is used for guidance only in those rare cases in which the MRI-detected abnormality cannot be seen on second-look ultrasound. Ultrasound guidance confers many advantages. It is performed in a more comfortable position than the other two guidance modalities, it uses no ionizing radiation, and it provides real-time visualization of the needle. It is our belief that a physician performing minimally invasive procedures should be facile with ultrasound and ultrasound-guided interventions to provide the patient with the advantages of this guidance modality enumerated above.

In concert with the improvements in imaging, there have been marked improvements in tissue acquisition. Percutaneous histologic tissue acquisition techniques currently in use, also referred to as minimally invasive breast biopsy, include large-core biopsy (typically 12–14 gauge) (Fig. 10-12A through C), including the Monopty and Maxcore by Bard and the Achieve needle by Cardinal Health; the vacuum-assisted biopsy (VAB) (typically 7–11 gauge), such as the Mammotome from Ethicon Endo-Surgery, the EnCor from SenoRx, and ATEC from Hologic (Fig. 10-13A through C), and larger tissue acquisition systems, such as the Halo from Rubicor and the en-bloc from Neothermia Corporation (Fig. 10-14A and B). Using smaller needles may risk the occurrence of higher false-negative rates. Fine-needle aspiration (FNA) techniques may be used for biopsy of axillary or internal mammary lymph nodes but are otherwise felt to be less desirable than histologic tissue acquisition techniques. The larger tissue acquisition systems (Rubicor and en-bloc) appear to offer little advantage over VAB for diagnostic procedures. Investigation of their therapeutic potential is ongoing.

Figure 10-12 A, Monopty Disposable Biopsy System. B, Maxcore Disposable Biopsy Instrument. C, Achieve Automatic Biopsy System.

(A, Courtesy of C.R. Bard, Covington, Georgia. B, Courtesy of Bard Peripheral Vascular, Inc., Tempe, Arizona. C, Courtesy of Cardinal Health, Dublin, Ohio.)

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