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Stereotactic Breast Biopsy.

When a woman is informed about a mass in her breast, anxiety and concern over possible malignancy naturally follow. A rapid, accurate and minimally invasive diagnostic technique can help ease some of that anxiety. Stereotactic breast biopsy, a relatively new procedure, offers quick assessment of breast lesions and provides an alternative to surgical biopsy for many indications.

First introduced in Switzerland in 1976, stereotactic procedures use mammography and stereotactic principles to biopsy breast lesions with needles. The first dedicated, prone stereotactic table was introduced at the University of Chicago in the mid 1980s, and in 1989 Parker reported on stereotactic biopsies using an automated biopsy gun and a large-gauge needle. Accuracy rates increased dramatically with this approach.[1] In late 1992, the time required to process images decreased with development of digital spot mammography for stereotactic guidance, making biopsies faster and more accurate.

One hurdle to the growth of stereotactic breast biopsy, at least early on, was lack of acceptance by surgeons. Because the technique shifted greater responsibility to radiologists, some surgeons felt threatened. However, from a patient's point of view, competent, uninterrupted care is more important than who provides the care.[2]

Today, stereotactic core-needle biopsies have become an accepted method for biopsy of nonpalpable lesions, with a reported sensitivity ranging from 79% to 100%. In addition to saving money (they are about 75% less expensive than surgical biopsies), stereotactic procedures have achieved a high level of patient and physician acceptance.[3]

Stereotactic Biopsy Vs Needle Localization

In traditional breast biopsy, radiography assisted solely in placement of a localization wire. The patient was transferred, with wire in place, to a surgical suite for open biopsy. With stereotactic biopsy, the entire procedure can be performed in the radiology department. (See Fig. 1.) In some cases, the procedure can take place immediately following mammography.[2]

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Many physicians argue that one-stage procedures, in which excisional biopsy is followed immediately by definitive surgery, such as mastectomy or lumpectomy, represent an advantage for open biopsy. However, one-stage procedures are uncommon, partly because of low rates of malignancy and partly because the physician normally consults with a patient about all treatment options prior to definitive surgery.

Studies have shown that as many as 9 out of 10 patients biopsied may have benign lesions. The documented miss rate for excisional biopsy, its substantial cost compared with percutaneous methods and the physical and psychological trauma associated with surgical procedures have increased favor for all percutaneous methods.[1]

Core Biopsy vs Fine-needle Aspiration

Physicians began replacing open biopsy with fine-needle aspiration biopsy of the breast to reduce the number of 2-stage surgical procedures (ie, open biopsy and a second, definitive surgical treatment.) In fine-needle aspiration biopsy, a 21- to 23-gauge needle with an attached syringe is passed through the suspicious area several times, and the extracted samples are placed on glass slides. Fine-needle aspiration yields cellular material suitable for cytologic evaluation only. Accurate evaluation of fine-needle samples requires a cytopathologist, a specialty not available in all facilities.[1]

Many surgeons did not like relying on fine-needle aspiration biopsy results because in many cases insufficient tissue was obtained. Samples acquired with this method also produced a high false-negative rate and occasional false-positive results. Often, the physician was unable to deliver a definitive benign diagnosis.[4] (See Table 1.)
Table 1
Comparison of Fine-needle Aspiration
And Core-needle Biopsy Techniques
For Nonpalpable Breast Lesions1

                         Fine-needle    Core Biopsy
                         Aspiration

Needle size (gauge)      20 to 22       11 to 14

Guidance techniques      Ultrasound,    Ultrasound,
                         stereotactic   stereotactic

Pathologic evaluation    Cytology       Histology
of sample

Rate of inadequate       0% to 37%      <1%
sample

Differentiates in situ   No             Yes
from invasive cancer?

Cost(*)                  $              $$

(*) The cost per procedure depends predominantly on the
choice of guidance technique. The cost of the needle is also
a contributing factor: 22-gauge hypodermic needles used for
fine-needle aspiration are relatively inexpensive; automated
biopsy guns use needles of variable gauges, ranging from 14
to 21, and are intermediate in price; the 11-gauge core biopsy
needles used with the vacuum-assisted biopsy probe are
most expensive at approximately $200 each.


Core biopsy uses a different needle than fine-needle aspiration biopsy. In core biopsy, a large cutting needle, most commonly 14 gauge, is advanced into the breast using an automated instrument to extract a core of tissue. Because more tissue is removed, insufficient sampling is rare. Tissue obtained from stereotactic core biopsy requires only histologic examination.

Most of the preliminary steps for fine-needle aspiration are the same as for core biopsy. However, in the fine-needle technique, placement of the needle in the lesion differs slightly -- it should be in the distal portion of the mass.[5]

Advantages and Contraindications For Core-needle Biopsy

To core biopsy a breast lesion with stereotactic guidance, only a small incision is required. The core needle is passed through that incision, leaving little to no breast deformity or scarring. Internally, the technique leaves no permanent effect that might interfere with interpretation of subsequent mammograms.[6] In addition to offering clinical accuracy, stereotactic biopsy is much less expensive than surgical biopsy.[3]

For nonpalpable and low-risk lesions, stereotactic biopsy is generally the procedure of choice. Over the past few years, it also has become increasingly useful for high-risk lesions. For patients with a suspicious abnormality seen on only one mammographic projection, lesions that are not visible with ultrasound and lesions located deep within large, fatty breasts, stereotactic biopsy is indicated. Certain patients with prior surgical treatment of breast cancer are also good candidates for this minimally invasive technique.[7,8]

Stereotactic biopsy is not the preferred procedure for every patient with a nonpalpable breast lesion. In some cases, patients are too large for the dedicated table. On the other hand, patients with smaller breasts may not be good candidates for this procedure because the compressed thickness of their breasts does not allow for a full throw of the biopsy gun.[9]

Patients undergoing stereotactic biopsy must be able to lie prone (depending on the equipment) and still for as long as 30 to 60 minutes.[10] Lesions measuring less than 5 mm in the longest dimension may be contraindicated for core biopsy because the entire lesion could be removed.

Procedural and Patient Considerations

Appropriate work-up and patient selection for stereotactic biopsy ensure that the procedure is performed on the right patients. The decision to perform a stereotactic biopsy depends on the particular lesion identified with mammography as well as other considerations.[11]

Medical History

Pertinent medical history questions include current medications, any physical limitations that would prohibit the procedure and any medical condition that would indicate use of prophylactic antibiotics.[12] A medical history can reveal several possible contraindications to stereotactic breast biopsy. For example, patients with certain bleeding disorders and those on anticoagulant therapy should not have the procedure unless their coagulation status is corrected. Bleeding can occur in any patient who has taken aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) within the previous week. Movement disorders, such as Parkinson disease, usually cause too much patient motion for successful stereotactic biopsy. Patients who have undergone recent abdominal surgery and patients with pacemakers may have trouble maintaining the prone position.[5]

A complete imaging work-up includes mammographic studies and follow-up imaging. It is helpful to check the thickness of breast parenchyma under compression at the time of the diagnostic workup to ensure the thickness is adequate to accommodate the movement of the needle.

Imaging and medical history information help physicians determine if stereotactic biopsy is the best procedure to study a given lesion. At times, findings of diagnostic mammography or sonography plus physical exam findings reveal a low probability of malignancy and may eliminate the need for biopsy.[5,11]

Scheduling, Screening and Informed Consent

Scheduling patients for stereotactic breast biopsy normally occurs through a referral channel guided by physicians and payers. An appropriate referral allows for follow-up reports to be sent from the radiology facility to the referring physician.

Other times, the biopsy occurs immediately following the discovery of an abnormality. This depends on the facility's readiness for emergency procedures and referral patterns and requirements. Normal scheduling protocols for stereotactic breast biopsy include obtaining pertinent patient information, completing a medical history, reviewing insurance and discussing follow-up appointments for benign biopsies.

Scheduling during set time periods better integrates stereotactic biopsy procedures into the general radiology practice. Approximately 45 minutes to I hour per case is the norm. Scheduling generally is done by the referring physician's office, and the scheduler should inquire about pertinent medical history, such as use of anticoagulants, at that time. This allows the patient to discontinue anticoagulants, aspirin, etc prior to the procedure. Likewise, prophylactic antibiotics can be prescribed.[11-13] Patients scheduled for prone-position procedures may be instructed to have only a light meal prior to the biopsy.[11]

Before beginning the procedure, staff must obtain the patient's informed consent. This includes describing the proposed biopsy method, its limitations, the procedure's risks and possible side effects.[14]

The purpose of informed consent is to encourage patient autonomy in medical decision making. Consent takes a variety of forms, but generally consists of written agreements after the patient receives verbal and written information. The actual steps depend on state and federal laws, hospital or provider policy and adherence to national standards and guidelines.[7]

Explanation of the procedure is best provided in the room where the biopsy will take place, so that the patient can see the setup and equipment.[5] Experts caution that information should be presented factually, with no possibility of perceived coercion or manipulation of the patient. Too often, patients receive a great deal of information about the procedure and its risks, but not enough about the procedure's goal. To make an informed decision, patients should understand what the biopsy is expected to accomplish.[7]

Although they occur rarely, risks discussed in the consent process should include potential bleeding and infection. Hematoma also occurs rarely, and normal bruising and discomfort can be expected. Patients should be informed of the possibility that a stereotactic breast biopsy procedure may not yield adequate material for study and that surgical resection after the procedure may be indicated.[5]

Patient Cooperation and Debility

Patient cooperation is critical for stereotactic breast biopsy because of the effects of patient motion on the procedure's accuracy.[2] A report on canceled stereotactic biopsy procedures indicated that 8% of cancellations were caused by patients' inability to tolerate the procedure.[1] The medical history may reveal possible problems. These include:

* Indications that a patient cannot maintain a prone position for the duration of the procedure, such as arthritis or other musculoskeletal conditions, heart failure, abdominal conditions, psychosis, extreme anxiety or certain emotional difficulties.

* Severe coughing.

* Excessive weight. Most prone tables have weight limits, generally about 300 lbs.

* In the case of upright rather than prone procedures, inability to remain immobile and upright for an hour or so.

* Inability to understand informed consent and comply with instructions during the procedure.[1,9,12]

Medications

Aspirin should be discontinued 48 to 72 hours prior to breast biopsy. Heparin and warfarin should be discontinued for 24 hours prior to the procedure. There is some controversy over the use of prophylactic antibiotics prior to low-risk procedures such as stereotactic breast biopsy. Patients with prosthetic heart valves, mitral valve prolapse or a history of rheumatic fever may require preprocedural antibiotics, usually cephalexin or erythromycin. Generally, if a patient receives antibiotics prior to a dental procedure, use is indicated before stereotactic biopsy. Patients usually take one dose within an hour of the procedure and a second dose about 6 hours later. No other medications are considered contraindications. If a patient requires or requests a sedative, diazepam or another sedative can be administered just prior to the procedure.[5,13]

Lesion Selection and Suitability

The American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS) developed a lexicon for mammography designed to standardize reporting and reduce confusion in breast imaging interpretation. The system also helps facilitate outcome monitoring. The lexicon categorizes mammographic findings as follows:

1. Negative (N).

2. Benign finding (B).

3. Probably benign finding (P).

4. Suspicious abnormality (S).

5. Highly suggestive of malignancy (M).

Lesions in category 3 (probably benign) usually are managed with 6-month follow-up mammograms, while those in categories 4 and 5 (suspicious or highly suggestive of malignancy) indicate biopsy.[1] Classic benign abnormalities do not require biopsy. Those that are probably benign have such a low incidence of subsequent malignancy that, in most cases, biopsy adds unnecessary cost and cannot be justified.[13]

Some clinicians argue that fine-needle or core biopsy of low-suspicion lesions reduces anxiety for nervous women, but one study showed that stress was greater for those undergoing biopsy than for those following up with mammography.[1] On the other hand, stereotactic biopsy is a viable alternative for patients who are unwilling to wait 6 months for follow-up mammography.[15] The greatest cost benefit comes from percutaneous biopsy of intermediate-suspicion lesions (ie, Bi-RADS category 4).[1]

Lesions classified as BI-RADS category 5 (probably malignant) increasingly undergo stereotactic biopsy. Even though surgery may be inevitable, the preoperative diagnosis offered by the biopsy gives the surgeon a chance to discuss treatment options with the patient prior to surgery. Studies show a high histologic agreement between stereotactic core biopsy and surgical excision for differentiating among several types of breast cancer, such as ductal carcinoma in situ vs invasive cancer. Distinction between lobular carcinoma and intraductal carcinoma also is very good.[15]

When a highly suspicious abnormality indicates percutaneous biopsy, the clinician must select the imaging technique for guidance and the method to be used (fine needle, core or both) based on characteristics of the abnormality. For example, the physician considers factors such as the lesion's size. Fine-needle aspiration may be preferred for very small abnormalities because a core biopsy might remove the entire lesion. Patients who present with multiple, separate and discrete lesions benefit from stereotactic biopsy because biopsy findings distinguish benign abnormalities from those that require surgical excision.[16]

Fine-needle aspiration of solid tumors has increasingly reduced the need for excisional biopsy in these palpable masses. Introduction of stereotactic imaging to guide fine-needle placement resulted in increased sensitivity and specificity. For nonpalpable lesions, stereotactic core biopsy generally has replaced fine-needle aspiration as the biopsy method of choice.[17]

Some types of lesions are more problematic for stereotactic methods. Lesions that reveal atypical ductal hyperplasia histology at core biopsy have about a 50% chance of proving to be carcinoma after surgical excision. Many clinicians recommend following up a diagnosis of atypical ductal hyperplasia with surgical excision.[15]

Likewise, suspected radial scars or scattered, non-clustered, indeterminate calcifications may not be suitable for needle biopsy. Radial scars are difficult for the histologist to distinguish from tubular carcinoma. Scattered calcifications without focal clustering make diagnosis difficult because they can represent sclerosing adenosis or ductal carcinoma in situ. An excisional biopsy more completely evaluates the abnormality and may find disease remote from the area of calcification.[16]

Microcalcifications

Core-needle biopsy is particularly helpful in evaluating multiple clusters of microcalcifications because microcalcifications that are fine and scattered are poor candidates for fine-needle aspiration. Imaging of fine microcalcifications has sometimes been difficult under stereotactic technique.[18] However, stereotactic imaging and core biopsy remain the standards of choice for work-up of most microcalcifications.[19]

The advent of digital imaging in stereotactic guidance has led to improved localization of microcalcifications. The technology offers increased resolution and additional magnification, thus improving visualization.[13] (See Fig. 2.)

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Development of core sampling techniques and, in particular, vacuum-assisted sampling has led to more accurate sampling of calcifications. One study showed that stereotactic vacuum biopsy provided wide sampling of calcifications and allowed complete removal of the mammographic lesion in some cases.[20]

Specimen radiography can confirm that a calcification sample was indeed obtained. If calcifications are not present in the initial cores, sampling should continue until calcifications are obtained. However, patients can tolerate only so many attempts, and if no calcifications appear in the first 5 to 10 specimens, additional attempts have a low possibility of success and should be discontinued. This is particularly true with vacuum-assisted sampling because repeated attempts can destroy breast architecture and cause hemorrhaging. Failure to retrieve microcalcifications with this method usually indicates that the wrong site in the breast has been sampled.[21]

Principles of Stereotactic Guidance

Coordinate systems are used to target a precise location in the breast for the biopsy needle. (See Fig. 3.) In general, stereotactic localizations are accurate to within 1 mm. Two types of coordinate systems typically are used in stereotactic guidance: the polar coordinate system and the Cartesian coordinate system.

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The polar coordinate system defines a target by distances from a fixed point and the angular distances from a reference line. Most often, coordinates are represented by H (horizontal), V (vertical) and D (depth). The polar system is accurate, but it is more difficult for the user to notice errors.

The Cartesian coordinate system defines the target using distances from the 3 axes that intersect at right angles: x, y and z. This system is advantageous because it is intuitive and familiar to operators. Because it is so simple to use, the needle position can he adjusted easily.

With the Cartesian system, the x (horizontal), y (vertical) and z (depth) axes are assigned number coordinates.[13] Angled stereotactic images are acquired by moving the x-ray tube 15 [degrees] to the right and then to the left along the x axis. (See Fig. 4.) The lesion's position on these 2 images is compared with a standard reference point, and a formula is applied to precisely calculate the lesion's depth. This allows for accurate 3-D needle positioning and collection of multiple samples.[22,23]

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Dedicated vs Add-on Equipment

Stereotactic breast biopsy cannot be performed with standard mammography equipment. It requires a dedicated unit for prone positioning or an add-on unit

for upright positioning.[6] (See Fig. 5.) The upright add-on unit was introduced in 1988 to accommodate the automated biopsy gun. However, the original add-on unit had some significant clinical and technical limitations. Because patients sat upright in a chair during the biopsy, many felt faint, while others had trouble keeping still in that position. All patients had some degree of motion, which reduces the technique's accuracy.[2]

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Despite improvements, current upright units still allow the patient to see the procedure as it is performed, increasing anxiety and the likelihood of patient motion. Positioning of the needle may need to be within millimeters of a small lesion, so any motion is generally unacceptable. Also, patients are more likely to experience a vasovagal reaction during upright procedures. Finally, these units provide less space for the radiologist and mammographer to perform the procedure.

Advantages of upright add-on units include cost (about one fourth the cost of dedicated prone tables), the ability to use the mammography equipment for standard exams and better imaging of certain lesions. When lesions are located near the chest wall or in the axilla, they can be better imaged with upright units.[23]

Dedicated prone units are designed so that the patient can lie prone on the unit's table with her breast through an opening near the head of the table.[4] The mammography unit and needle guidance stage are located under the table, allowing the radiologist and mammographer more working space. Compression holds the breast against the image acquisition device, and the biopsy probe is located between the device and the x-ray tube.[23]

Because the patient cannot see the needle piercing her breast, she is generally less anxious. She is also more comfortable and able to remain still in the prone position.[4] Prone units with center aperture design allow for patient positioning at either end of the table, providing 360 [degrees] access to the breast. (See Fig. 6.)[24] Unfortunately, prone tables are much more expensive than add-on units and can be used only for stereotactic breast biopsies. Facilities using this equipment must have a high enough volume of procedures to justify the cost and space requirements.[1]

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At some facilities, prone tables are used for sonography as well. This makes it possible to perform ultrasound-guided and stereotactic-guided procedures in the same room, so that all supplies can be stocked in one room. Patients with lesions near the chest wall and in the axilla may require sonographic guidance because the position of these lesions makes them difficult to image stereotactically on prone tables.[23]

A 1998 study by a New Zealand hospital radiology department found that 90% of patients could undergo stereotactic breast biopsy using an add-on unit with the patient in the decubitus position. This positioning eliminated problems with syncope or vasovagal reaction. Another report described similar success with a dedicated reclining chair, although there were some minor technical problems such as larger breasts sliding when the x-ray tube was horizontal and the film holder vertical. Overall, however, the study reported good patient comfort and adequate immobilization.[25]

The Mammographer's Duties

Mammographers who assist in performing stereotactic breast biopsies should be experienced and knowledgeable in mammography technique. Prior to the procedure, the mammographer should review the mammographic work-up with the physician, discussing the lesion's location and planning the biopsy approach.

The mammographer is responsible for calibrating the equipment according to manufacturers' recommendations prior to the procedure. The mammographer greets the patient on arrival, reviews procedural details and is responsible for positioning the patient. In addition, he or she is responsible for imaging the lesion's region.[11]

Image Acquisition and Management

Stereotactic breast biopsy requires that lesions be visualized with enough clarity to distinguish them from surrounding tissues. This clarity provides the basis for targeting, localization and sampling with the biopsy needle. This differs from the goals of standard mammographic imaging, which are detection and characterization of lesions.

Unlike mammography, positioning the lesion close to the compression surface and away from the image receptor increases the object-image receptor distance. Also, stereotactic breast biopsy results in reduced compression over the imaging area. These 2 factors complicate imaging by increasing geometric blur and degrading visibility of detail. Other imaging properties become even more critical as the mammographer attempts to minimize further image degradation.[24]

Successful lesion targeting is critical to the success of stereotactic breast biopsy.[23] Stereotactic image acquisition begins with obtaining a scout image in the projection that places the lesion nearest the skin. By placing the lesion nearer the skin, more room is given for the excursion of the biopsy needle. The lesion should be centered within the aperture in the compression plate.

The shortest distance approach also allows for greater needle placement accuracy. Caution should be taken to ensure that the lesion is deep enough relative to the skin surface to accommodate the prefire position of the needle tip.[4,5] The chosen approach should offer good visualization of the target lesion.[23] (See Fig. 7.)

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With an alpha-numeric grid over the breast during scout image filming, the skin over the lesion can be marked with a felt-tip pen. This mark is used to position the patient's breast for the biopsy procedure, with the mark at the center of the compression plate. When the scout film is made, the lesion should be centered on the horizontal, or x axis.

After a small scalpel incision is made and the needle placed to the right depth, prefire images are obtained with the needle in place. These films allow the radiologist to check the accuracy of needle placement. If the needle is correctly placed according to the z axis (depth) position, both prefire stereotactic images should show the needle directly superimposed on the center of the lesion. The radiologist then pulls back just enough to accommodate firing distance. In the case of a vacuum suction probe, the chamber should be adjacent to or within the lesion.

With x-axis errors, the needle is too far right or left of the lesion on both prefire images when looking directly at the aperture of the compression plate. Y-axis errors mean the needle is placed caudad or cephalad to the desired location on the 2 images. If the needle appears well positioned on one of the stereotactic views, the view with poorer position is actually more accurate.

If positioning is incorrect, the radiologist has 2 options. He or she can make corrections based on prefire image information (removing and repositioning the needle) or retarget with another set of coordinates and the needle still in place. However, if the needle obscures the lesion in any way, it should be removed and a new set of prefire images obtained.

After correct positioning, the patient is told that the biopsy will be performed and that she will hear the needle or vacuum gun. (This sound should be demonstrated for her prior to the procedure.) Two stereotactic postfire images are then obtained to document the needle traversing the center of the lesion.[5,23]

The Role of Digital Imaging

Digital imaging technology has dramatically improved stereotactic guidance for breast biopsy. With a digital image receptor, the time required to perform the procedure is decreased by one half, enhancing the patient's comfort and her ability to remain motionless. Digital technology offers near real-time imaging.

Another advantage of digital imaging is reduced radiation exposure. The technology provides a small field of view and hence a smaller area of the

breast is exposed to radiation. Imaging of faint lesions, especially calcifications, can be improved in digital imaging by increasing the kVp. While this would decrease contrast in film-screen imaging, it improves digital imaging.[5,13,26] Image display is more operator dependent with digital imaging.[23]

Positioning

Proper positioning of the patient and the C-arm are a critical responsibility for the mammographer. Optimal positioning can be achieved only through close cooperation of the radiologist, mammographer and patient. With dedicated prone equipment, the patient's arms are usually at her side and her face turned away from the radiologist's work area. For comfort, the mammographer can place a thin pillow between the table and the patient's abdomen. A small pad may help shoulder (generally the ipsilateral shoulder) or rib discomfort.

When helping a patient who is uncomfortable, the mammographer should be careful not to raise the shoulder or ribs from the table. Pillows should be placed in the hollow of the neck rather than under the head, which can cause additional stress and strain on the shoulder and neck.[5,27]

When the patient is comfortably positioned on the table, the mammographer positions the breast. The mammographer and physician work together to determine the starting projection, and mammographers should use their creativity, experience and knowledge to alter the position when necessary. A variety of projections and oblique angles can be used. Adequate tissue thickness, visualization and lesion location all factor into deciding on an imaging approach. Standard projections for each breast quadrant can be chosen with 360 [degrees] capabilities.[23,27] (See Fig. 8.)
Fig. 8. This table correlates access to the 4 quadrants with the
possible projections. (Reprinted with permission from: Willison KM,
to Stereotactic Breast Biopsy. Cambridge, Mass: Blackwell Inc;
1996:157.)

Stereotactic Projections

                 Cranio-         Caudal-         Medio-
                 Caudal          Cranial         Lateral

Location      [ILLUSTRATION   [ILLUSTRATION   [ILLUSTRATION
of              OMITTED]        OMITTED]        OMITTED]
abnormality

Upper Outer         X
Quadrant

Upper Inner         X                               X
Quadrant

Lower Inner                         X               X
Quadrant

Lower Outer                         X
Quadrant

                 Latero-         (SM-IL)          IL-SM(*)
                 Medial        (ACR-MLO)(*)      (ACR-LMO or
                                 Supero-       Reverse Infero-
                                Medial to        Lateral to
                              Infero-Lateral    Supero-Medial
                                 Oblique           Oblique

Location      [ILLUSTRATION   [ILLUSTRATION     [ILLUSTRATION
of              OMITTED]         OMITTED]         OMITTED]
abnormality

Upper Outer         X            X slight             X
Quadrant                       oblique only

Upper Inner                         X
Quadrant

Lower Inner                         X                 X
Quadrant

Lower Outer         X                                 X
Quadrant

                  SL-IM         IM-SL(*)
              (ACR-SIO)(*)       Infero-
                 Supero-        Medial to
               Lateral to        Supero-
              Infero-Medial      Lateral
                 Oblique         Oblique

Location      [ILLUSTRATION   [ILLUSTRATION
of              OMITTED]        OMITTED]
abnormality

Upper Outer         X
Quadrant

Upper Inner         X         X
Quadrant

Lower Inner                   X
Quadrant

Lower Outer         X         X
Quadrant


Positioning on a prone table can be disorienting at first compared with standard mammography positioning. When the breast hangs from the body in the prone position, perspective is altered.

With mammography add-on units, speed is critical for the patient's sake, and the mammographer and entire biopsy team should be comfortable with their roles to complete the procedure efficiently and accurately. More preparation before the patient is positioned can shorten the procedure time and reduce complications. Practice with a phantom can help the mammographer maintain skill with stereotactic equipment.

Mammographers should make patients as comfortable as possible in the upright position. Pillows or other props can provide back support. Support for the patient's feet and legs also helps her remain comfortable and motionless. When possible, the patient should be positioned to prevent her from seeing the biopsy procedure and sterile tray. Constant communication with the mammographer and radiologist help keep the patient comfortable.[27]

Mammographers and radiologists should remain well versed in new techniques for positioning difficult lesions. For example, posterior abnormalities may seem inaccessible but can be successfully imaged on stereotaxis by repositioning the patient with her rib cage relaxed or the ipsilateral shoulder at the rim of the opening or by rolling her into a steeper oblique position. Larger breasts pull posterior tissue down into the opening, making it easier to image posterior lesions. Also, lowering the ipsilateral arm through the opening helps bring a posterior lesion into view. (See Fig. 9.)

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Subareolar abnormalities make coverage of the biopsy window difficult because of inadequate amounts of tissue. If the breast is large enough, the nipple can be rotated upward or downward in the appropriate projection to bring more breast tissue behind the lesion.

Small breasts also can be difficult to manage, but many of the same techniques applied to posterior lesions can help.[27] A recent study estimated that as many as 10% of patients' breasts were compressed to dangerously thin depths considering the needle stroke margin. Because many of these exams had to be cancelled, the authors of the study developed a breast bolster that helps control the radius or peripheral dispersion of a compressed breast.

Made of plastic sponge, these compressible devices are compatible with all biopsy tables or platforms. The bolster is placed between the compression plates and surrounds the entire periphery of the breast. An overall increase in breast tissue depth of 36% was demonstrated, but the authors cautioned that the bolster worked only with sufficiently large breasts.[28]

Large breasts can touch the C-arm, and caution should be used to avoid injury. Larger breasts present the imaging complication of increased blur due to the greater distance between the lesion and the image receptor. Also, thicker breast tissue creates more scatter, reducing abnormality contrast. Choosing a C-arm approach that makes the breast as thin as possible and demonstrates the abnormality in fat helps improve the quality of lesion imaging in large breasts.[27]

Sterile Procedure and Tray

Even though risk of infection from percutaneous breast biopsy is low, it still is critical to maintain sterile techniques. In core biopsy, the skin under the aperture, the needle and the needle guide remain sterile. The remainder of the field is nonsterile. Mammographers and physicians should use caution when handling the needle and when touching the patient's skin surface to avoid any contamination.[18]

A sterile tray should be set up before the radiologist arrives to perform the biopsy. Sterile supplies are placed on a towel and are basically the same for procedures using biopsy guns or vacuum-assisted devices. A scalpel blade, syringes with prefilled local anesthetic, a small needle-nosed hemostat, alcohol-soaked swabs, sponge sticks, sterile saline solution, 4 x 4-inch sterile gauze sponges, forceps, sponge clamps and a specimen cup and lid are standard tray contents.[13,29] Gloves, wound closure strips, additional dressings and instant icepacks also are normally included on the tray.

Specimen Retrieval and Handling

When the time comes for needle insertion, the skin is prepped with an antiseptic swab. A local anesthetic, such as lidocaine, usually is injected into the skin at the insertion site. A small needle, typically 25-gauge, is used to help prevent the patient from pulling away and moving from the targeting position. Most patients can tolerate breast biopsy with minimal local anesthesia. After the breast is anesthetized, the physician makes an incision about 2 to 3 mm long to allow for manual insertion of the needle to target depth.[11]

Automated biopsy guns with 14-gauge Tru-Cut-type needles obtain core samples at the push of a button. Ease of firing allows the radiologist to concentrate completely on lesion targeting. Because the guns fire rapidly, mobile lesions can be penetrated quickly, before they move out of the way. Rapid-fire technology also makes for better penetration of firm or fibrotic lesions.[4] The biopsy guns require multiple needle insertions to acquire the recommended number of cores. This number varies, but generally falls in the range of about 5 specimens per mass.[30]

Directional, vacuum-assisted biopsy devices are inserted once and rotated while in the breast to obtain cores from multiple lesion sites. A vacuum pulls some tissue into the sample notch, where it is cut and then transported back through the needle and out to the collection chamber.[1] Between each sample collection, the specimen is retrieved from the device's needle trough or collection chamber using forceps.

The samples are placed on a saline-soaked pad or in a small amount of sterile saline solution. Cores are placed in formalin for transportation to the pathology department.[11] Mammographers should label the specimens according to pathology department or lab requirements and submit the required requisitions and paperwork.[12]

Complete lesion removal may inadvertently occur with core sampling of small lesions. If postbiopsy images reveal that the lesion has been totally, or even largely, removed, the physician should place a percutaneous clip to mark the site. If the abnormality proves cancerous, the clip helps to locate the lesion for needle localization and therapeutic surgery. Even if the lesion proves benign, the clip helps locate the exact location of the previous biopsy. The clips are tiny and don't obstruct future mammograms. All blood and fluid should be suctioned from the biopsy cavity before clip placement. After deployment of the clip through the biopsy probe, a final set of stereotactic views should be taken to document appropriate placement.[1,29]

Specimen radiography is an important part of stereotactic breast biopsy used to evaluate microcalcifications. Cores can be placed on a piece of x-ray film that is attached to the 5-cm aperture in the front compression paddle. A magnified view of the cores confirms that some of the calcified lesion was obtained. Otherwise, another pass of the target area is required.[11]

A 1999 study outlined how core specimens could be aligned in a dry plastic container for specimen radiography. The cores containing calcium were identified radiographically and placed in a histologic tissue cassette. Each cassette was closed and placed in ajar of formalin. Remaining core samples then were placed free-floating in the same jar. This allowed the pathologist to concentrate on the samples identified as calcifications.

Specimen radiography and this specimen handling technique also may be helpful in confirming the presence of any targeted mass in a specimen.[31]

Universal Precautions

Mammographers, radiologists and other personnel involved in the biopsy procedure, including those who transport specimens, should be trained in universal precautions pertaining to handling blood and bloodborne pathogens. The Occupational Safety and Health Administration (OSHA) sets the rules and regulations for handling blood and specimens, equipment cleaning and staff training.[12]

Primarily, OSHA is concerned with transmission of the human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). The agency issued the Bloodborne Pathogens (BBP) standard in 1991 based on the premise that a combination of engineering and work practice controls, training, personal protective equipment, medical surveillance, hepatitis B vaccination, various signs and labels and other requirements would minimize the risk of disease transmission to health care workers.

In November 2000, President Clinton signed the Needlestick Safety and Prevention Act, which required OSHA to revise parts of the BBP standard within 6 months of enactment. The revisions were meant to clarify broad categories rather than to impose new restrictions on employers. Comments on the revised BBP were solicited until March 19, 2001[32] and the new standard became effective on April 19, 2001.

Wound Management

Mammographers continue to play a key role after the biopsy procedure. First, the breast is compressed for several minutes until hemostasis is secured.[4,11] Compression can be applied while the patient's breast is still in the compression paddles. This puts pressure on the lesion and the path of the biopsy.[29] The skin is cleaned, and antibiotic cream can be applied. The incision should be closed with a sterile bandage and covered with a dressing. An ice pack can be provided to help reduce swelling when bleeding is pronounced.

The patient should be instructed to leave the bandage on for 24 to 48 hours. No dressing care normally is required after that. For the most part, patients can shower and return to normal activity, although they should avoid strenuous arm activity for about 24 to 48 hours. Over-the-counter pain medications can help with discomfort. Patients should be informed about when to expect results and follow-up. In many cases, the patient is re-examined the next day and again in about 1 week to check for complications.[11,29]

Complications

Complications are rare for stereotactic breast biopsy procedures. These complications include vasovagal reaction, infection and bleeding.[1]

During the procedure, vasovagal reactions and fainting can occur in patients in the upright position. Anxiety is the chief cause of this complication, and many patients suffer a reaction before needle placement. Mammographers should watch for clinical features such as light-headedness, nausea, perspiration, pallor, yawning, sighing and subsequent fainting. To manage vasovagal reactions, mammographers should place the patient in a recumbent position with legs elevated and monitor blood pressure.[7]

With the standard 14-gauge needle, estimated frequencies of hematoma and infections are less than 2 in 1000 for both complications. Because infections are rare, debate still exists on the use of prophylactic antibiotics before stereotactic breast biopsy. Patients with severe valvular disease probably should take these preventive measures.[1]

About 4% of patients experience internal bleeding, but none serious enough to require intervention. Hematomas can occur but rarely require surgical intervention. Significant postbiopsy discomfort occurs in only about 5% of patients and nearly all can be treated with nonprescription anti-inflammatory drugs.[29]

Mild bruising and discomfort are expected following percutaneous breast biopsy. Long-term changes to mammograms resulting from the procedure have not been documented. Short-term findings of air and hematoma occur immediately after vacuum-assisted biopsy, but resolve rapidly. Other effects that result from surgical biopsy, such as parenchymal scarring, architectural distortion and fat necrosis, do not occur with less-invasive approaches. Results of tissue sampling, such as defects in a lesion or missing calcifications, can be seen on 6-month follow-up mammograms.[5,20]

Follow-up

In addition to immediate postprocedure follow-up, recommended follow-up based on biopsy results is important. Core biopsy is a sampling method, and follow-up is particularly crucial for patients with benign but nonspecific findings. Accidental sampling of normal adjacent tissue can produce this result.[1]

Patient tracking after breast biopsy is the responsibility of the physician who performed the procedure. He or she should review the pathology reports on all biopsies.[1,5] Although no clear guidelines exist for follow-up, serial mammograms are recommended for patients with benign findings on core biopsy.[1,3] Because it is possible for any biopsy method to miss a cancer, follow-up is important to detect suspicious changes in abnormalities. Every facility performing stereotactic breast biopsy should develop a procedure for patient follow-up and reminders.

Follow-up guidelines should specify who will receive follow-up reminders (patient and referring physician), when letters are sent (1 or 2 months before scheduled follow-up) and how many letters are sent before the patient is considered lost in terms of follow-up.[33]

Specific recommendations for follow-up are based on the combined mammographic findings and histologic results of the biopsy. If there is discordance between histologic and imaging results, a repeat core biopsy or surgical biopsy may be recommended. If stereotactic biopsy results show atypical ductal hyperplasia, surgical excision always is recommended. If the biopsy's histology suggests the possibility of lesions best sampled with more tissue, such as phyllodes tumors or those with high malignant association (eg, radial scars), surgical biopsy should follow core biopsy.

Mammography usually is recommended in 6 months for concordant benign findings and at 6-month intervals thereafter for an undetermined period.[34] Unfortunately, compliance with follow-up recommendations is much better among patients recommended for surgical excision than for those recommended for imaging follow-up. Despite quality assurance programs with rigorous tracking procedures, patient compliance following percutaneous breast biopsy is problematic.[1]

A study to collect long-term, follow-up data on patients with benign biopsy findings determined a mean follow-up period of 34.6 months. In most studies, follow-up data was lacking for at least 25% of patients with benign findings. Authors have suggested improved education of physicians and patients about the importance of strict adherence to follow-up protocol, noting that physicians who received additional training regarding patient noncompliance issues ultimately had patients with better compliance results on follow-up.[34]

Follow-up discussion should be included in the patient's informed consent prior to the procedure,s Discussion of all results and follow-up communication should be documented in the patient's chart.[33]

Quality Assurance

Quality assurance in stereotactic breast biopsy has the same goals as in screening and diagnostic mammography: to determine the level of care physicians and the facility deliver, to ensure equipment functions properly and to help identify problems as they arise.[23]

ACR Requirements and Guidelines

In 1996 the ACR developed the ACR Standard for the Performance of Stereotactically Guided Breast Interventional Procedures. The standard was revised in 2000, and the most recent version took effect in January 2001.[35]

The ACR accreditation program for stereotactic breast biopsy is a voluntary program developed by the ACR Committee on Stereotactic Breast Biopsy Accreditation of the Commission on Standards and Accreditation.[36] However, in some states, accreditation by the ACR or a similar accreditation program of the American College of Surgeons is required for a facility to offer the service.[23]

The ACR program was developed as a result of concerns of radiologists, the government, national medical organizations and the public that only qualified personnel perform stereotactic breast biopsies. Many people also were concerned that biopsies be performed using appropriate equipment and that women receive the best possible tissue sampling with the lowest possible risk.

Specifically, accreditation goals are to confirm that the biopsied lesion corresponds to the one identified mammographically and to provide educational feedback to facilities. Other goals include providing feedback on ways to reduce the number of exposures required for appropriate positioning, establishing whether histologic findings concur with imaging findings and optimizing use of equipment. Stereotactic biopsy accreditation is available for 3 types of procedures: biopsy of masses, calcification biopsies and fine-needle aspiration cytology.

To apply for accreditation, the facility must complete a questionnaire concerning qualifications of all key personnel (physicians, medical physicists and radiologic technologists) and the facility's current quality control/quality assurance program. The supervising physician must ensure that all involved personnel meet the program's required qualifications. Phantom and clinical images must be submitted for review by a panel of medical physicists and radiologists. Facilities must submit images on hard copy film only; those that use film-screen systems may submit copies of films.

After all stages of initial evaluation are completed, the ACR issues a final report with specific assessments and recommendations. If a facility meets the criteria, the ACR awards a 3-year accreditation and sends a certificate and machine label for each accredited stereotactic unit. Units that do not meet the criteria receive specific recommendations to help them reapply.

On-site surveys are not required for accreditation, but to ensure that they maintain consistent quality, the ACR may conduct an on-site survey at any time during the 3-year accreditation period. Facilities chosen for survey receive advance notice.

New equipment from manufacturers may not be included in ACR accreditation until it is properly assessed and reviewed in the literature.[36]

MQSA Requirements

The Food and Drug Administration (FDA) conducts a mammography program through its Center for Devices and Radiologic Health (CDRH). Congress enacted the program, which regulates mammography but not stereotactic biopsy, under the legislation titled "Mammography Quality Standards Act" (MQSA) in 1992. The act ensures that all women have access to mammography to detect breast cancer at its earliest stages and that all have access to good quality mammography services. After several comment and amendment periods, the final regulations took effect on April 28, 1999.[37]

The FDA has stated that unless facilities performing stereotactic breast biopsy become voluntarily accredited with the ACR, the agency will implement a mandatory program under MQSA.[23]

Both ACR and MQSA accreditation provide an excellent basis for developing a quality assurance program and attesting to patients, referring physicians and payers that a facility performs at the accredited level. When a facility receives accreditation, the ACR notifies agencies such as the American Cancer Society. A facility should publicize its accreditation appropriately as well.[23,36]

Mammographer Qualifications for Stereotactic Breast Biopsy

Specific qualifications for radiologic technologists who perform mammography are outlined by MQSA.[38]

For a facility to be accredited by the American College of Radiology (ACR) Stereotactic Breast Biopsy Accreditation Program, its mammographers must meet the qualifications required under ACR's Standard for the Performance of Screening Mammography and the Standard for the Performance of Stereotactically Guided Breast Interventional Procedures. The standards are similar to MQSA and require that mammographers:

* Be certified by the American Registry of Radiologic Technologists (ARRT), hold state licensure or both.

* Participate in mammography-specific continuing education (CE) programs and on-the-job training under the supervision of experienced mammographers.

* Perform mammography on a regular basis.

* Demonstrate competence in breast positioning and compression and knowledge concerning technical factors, radiation safety, radiation protection and quality control.

* Receive continual supervision on image quality from the interpreting physicians.

Mammographers must have 3 hours of Category A CE in stereotactic biopsy to qualify for initial accreditation. Further, the ACR requires documentation of 5 stereotactic breast biopsy hands-on procedures on patients under the guidance of a qualified physician or mammographer.

For reaccreditation, the mammographer must complete 3 hours of Category A CE every 3 years after initial accreditation and must provide documentation of performing an average of at least 12 stereotactic biopsies per year.[35,36]

Acceptance Testing

The mammographer is critical to maintaining and documenting quality assurance efforts. Every facility performing stereotactic breast biopsy should appoint a designated quality control technologist. Radiology department managers should understand the significant time and training these duties entail and should allow adequate time in the mammographer's schedule to perform them.[14]

For stereotactic equipment, quality control begins with acceptance testing of the units prior to their use. Someone other than the equipment installer should perform these tests. This person should be qualified to evaluate the equipment's performance and objectively measure patient and operator safety. Medical physicists who perform acceptance testing on mammography units should receive additional training or preparation specific to stereotactic breast biopsy systems.[23,39]

Acceptance testing should include:

* Evaluation of equipment assembly, including the function of motorized and manual controls, verification of light-field to x-ray-field coincidence and assessment of x-ray beam limitation.

* Output calibration. Medical physicists can verify output and calibration of the stereotactic unit using a number of procedures modified from mammography unit testing.

* Phantom imaging. Multiple exposures are required on standard digital stereotactic units to capture all details of the standard ACR accreditation phantom.

* Focal spot measurement and line-pair resolution. Established procedures for evaluating focal spot size or line-pair resolution can be performed by the medical physicist. Both screen-film and digital modes are used to perform line-pair resolution evaluation.

* Radiation protection survey. Standard measurement techniques for mammography units help a qualified medical physicist evaluate the radiation safety of stereotactic equipment. The physicist must consider the range of orientations of the x-ray beam with respect to the table.

* Other acceptance tests. These include grid artifact evaluation to check for nonuniformities, targeting accuracy (a closed-loop test of the needle position, stereo position calculations and the user interface) and average glandular dose.

Acceptance testing not only ensures equipment is ready for use, but also provides baseline performance data to check for possible image degradation.[39]

Routine Equipment Testing After Installation

Routine testing after installation helps verify that equipment functions optimally. The ACR outlines a quality control program for stereotactic breast biopsy units. Tests are recommended at set intervals. Although medical physicists perform some of these tests, the following fall under the responsibility of radiologic technologists:

* Semiannual compression force testing in automatic and manual modes.

* Weekly phantom image testing to check image quality. The phantom test checks that film density, contrast, uniformity and image quality are optimal.

* Weekly visual checklist to guarantee stability and mechanical safety of the equipment, as well as proper functioning of the imaging system.

* Daily testing of localization accuracy before procedures are performed to ensure proper system alignment and calibration. Test procedures vary by manufacturer and type of system, and radiologic technologists should follow manufacturers' testing recommendations.

* If film is used, daily film processor quality control checks for consistent performance of the film processor. For facilities using a film-screen system, processor quality control for a 30-day period must be submitted for evaluation with clinical and phantom images. Film processor tests must include assessment of base plus fog density, mid-density and density difference, using the same film used at the facility. Base fog plus density should be within [+ or -] 0.05 of the established operating level, mid-density within [+ or -] 7-0.15 and density difference within [+ or -] 0.15.[23,36,38]

For digital equipment, proper functioning and setup of the monitor are important considerations. The coupling system and digital camera (charge-coupled device or CCD, analog-to-digital converter and the cooling system) should be tested based on the manufacturer's recommendations and information from the ACR.[12]

Stereotactic equipment requires daily calibration to check against the manufacturer's variances. The components of the micrometer (Fisher table) can loosen or become damaged, causing errors in alignment.[13]

Documentation, Charting and Reports

The ACR Standard for the Performance of Stereotactically Guided Breast Interventional Procedures outlines requirements for each procedure's permanent record. These include:

* Facility name and location.

* Date of examination.

* Patient's first and last names.

* Identification number or date of birth.

* Designation of left or right breast.

* Technologist identification number or initials. The physician's report should include:

* Location of the lesion in the breast.

* Type of procedure performed.

* Approach used.

* Local anesthesia, if used, with amount and type.

* Skin incision, if made.

* Any complications and resulting treatments.

* Specimen radiographs, if performed, and results of those radiographs.

* Clip placement, if done.

* Postprocedure mammograms, if any were performed.

The ACR standard also outlines documentation of patient follow-up. This includes:

* Identification of any delayed complications and required treatment.

* Pathology results.

* Record of communication with the patient, referring physician or both.

* Recommendations based on biopsy results and imaging information.

The standard adds that reporting of results to the referring physician or patient is the responsibility of the physician who performed the procedure and that reporting should be done in accordance with the ACR Standard for Communication: Diagnostic Radiology.[35]

Data for the entire facility should be collected and tabulated consistently. The number of each type of procedure performed (eg, stereotactic core, sonographically guided core, etc.), number of cancers diagnosed and number of complications requiring treatment should be recorded. Recording the number of lesions requiring repeat biopsy and the reason for repeat helps with outcomes and quality measurements.[23]

Patient images (both hard copy and digital) must be stored according to state and federal record retention laws for mammograms. Local health care facility procedures and clinical need also factor into record retention considerations.[35]

Medical Audit

Quality assurance is not just concerned with personnel qualifications and equipment function. Accuracy of image interpretation, appropriate patient recommendations and follow-up also are measured. The concepts and specifics of an MQSA mammography practice audit also can be applied to stereotactic programs.

To be useful, any audit must be well planned and properly executed and interpreted. The outcomes of the audit should be used to improve stereotactic breast biopsy procedures. The volume and type of data required for an audit can be daunting,[40] but ongoing medical audits are a necessity.[36]

Audit Data

At the very least, the ACR accreditation program requires data on the number of procedures done by type, the number of cancers diagnosed and the number of complications requiring treatment. For repeat biopsies and excisional biopsies following stereotactically guided procedures, the biopsy should be listed by number and indication (eg, whether or not the repeat resulted from a previous inconclusive result, technical failure, inadequate sample or a clinical finding that required more tissue.)[36]

Audit data can be collected manually, or the facility can purchase specially designed software to gather data. Many of these programs were developed recently for guiding complete mammography reporting systems.

Deciding the type of data to collect poses some challenges. The first step is to meet documentation and medical audit requirements of the ACR. Next, facilities should decide on a minimal or basic audit that meets these requirements or a more comprehensive audit.

Raw data is the actual data collected; "derived data" refers to subsequent calculations based on the raw data. Raw data typically includes information such as audit period dates, total number of examinations performed, risk factors, mammographic recommendation and biopsy results. Derived data includes categories like true-positive and false-positive result rates, recall rates, an estimate of procedure sensitivity, positive predictive value, cancer detection rate (per 1000 examinees) and accuracy of interpretation.[40]

Needle biopsies generally don't remove the entire lesion, but rely on sampling parts of lesions. Because the sample is small, as is the lesion, these procedures are subject to missing a significant portion of the lesion, or sampling error. Therefore, this statistic is one that should be tracked in medical audit/quality assurance data.[22,40]

Appropriate levels for comparison of medical audit data for stereotactic breast biopsy are not well established, but facilities can set their own levels of performance and identify deviations from it.[23]

Clinical Image Submission

When submitting films for accreditation or review, the images should demonstrate that needles are positioned within a lesion accurately for biopsy and that physicians performing biopsies possess the necessary skills for accurate needle placement. Accreditation reviewers assume that the images submitted for their review represent examples of the biopsy team's best work.

Some biopsy devices don't allow the clinical image reviewer to adequately assess pre- and postbiopsy needle position. Lateral arm devices and large core (larger than 11-gauge) device films may not be accepted for accreditation evaluation.

A 2-view mammogram (2 orthogonal projections) helps show the lesion to be biopsied clearly, and these films are required under the ACR accreditation evaluation guidelines. Additional criteria include marking only one lesion to be biopsied on each mammogram and labeling them according to ACR specifications. Facilities should make every effort to submit films of obvious lesions that show well-performed positioning and good biopsy technique. Images must be properly labeled with identifying information. Both phantom and clinical images must be from the same 3-month period.[36]

Conclusion

Aside from use of medical audit statistics for individual facility quality assurance efforts, the collection of follow-up and positive predictive value measurement data helps demonstrate overall effectiveness of stereotactic breast biopsy procedures. The ability to plan a definitive operation based on the findings of a percutaneous biopsy has simplified the treatment of many breast cancers.[3] High negative predictive values help patients and surgeons feel confident of a benign finding following stereotactic biopsy.[41]

Core biopsy has evolved to the point where its frequency in sampling nonpalpable lesions is now as much as double the use of preoperative needle localization in radiology practices. However, anxious patients who prefer excisional biopsy are not good candidates for percutaneous procedures, as it adds one more procedure to diagnosis and treatment.[1]

Stereotactic core biopsy is a cost-effective, well-tolerated and extremely accurate method for diagnosing certain breast lesions.[15] Because breast biopsy is associated with strong emotional responses from patients, and because most biopsies prove that lesions are benign, physicians promote techniques that minimize the surgical or invasive extent of the procedure.[6]

As technology continues to evolve, percutaneous diagnostic methods may advance to therapeutic use. In theory, stereotactic imaging combined with improvements in biopsy collection equipment and cancer therapies could lead to therapeutic excision or radiation/ laser therapy using stereotactic biopsy techniques.[2]

Directed Reading Continuing Education Quiz

Stereotactic Breast Biopsy

DRI0001007 Expiration Date: June 30, 2003(*) Approved for 2.5 Cat. A CE credits

To receive Category A continuing education credit for this Directed Reading, read the preceding article and circle the correct response to each statement. Choose the answer that is most correct based on the text. Transfer your responses to the answer sheet on Page 474 and then follow the directions for submitting the answer sheet to the American Society of Radiologic Technologists. You also may take Directed Reading quizzes online at www.asrt.org.

(*) Your answer sheet for this Directed Reading must be received in the ASRT office on or before this date.
1. According to the text, stereotactic breast procedures
   are less expensive than surgical biopsies at a
   rate of about -- %.
   a. 15.
   b. 50.
   c. 75.
   d. 90.

2. According to the text, one-stage procedures, in
   which excisional biopsy is combined with definitive
   surgery, are uncommon because:
   1. of low rates of malignancy.
   2. of high incidence of complications.
   3. physicians normally consult with patients
      concerning treatment options.

   a. 1 and 2.
   b. 1 and 3.
   c. 2 and 3.
   d. 1, 2 and 3.

3. In performing fine-needle aspiration, physicians
   normally use a -- gauge needle.
   a. 11 to 14.
   b. 15 to 17.
   c. 18 to 20.
   d. 21 to 23.

4. Which procedure yields cellular material suitable
   only for cytologic evaluation?
   a. fine-needle aspiration.
   b. core biopsy.
   c. surgical excision.
   d. needle localization.

5. Which of the following types of lesions are good
   candidates for stereotactic breast biopsy?
   1. nonpalpable, low-risk lesions.
   2. lesions not visible on ultrasound.
   3. lesions deep within large, fatty breasts.

   a. 1 and 2.
   b. 1 and 3.
   c. 2 and 3.
   d. 1, 2 and 3.

6. Medical questions at scheduling of breast biopsy
   can eliminate possible complications due to:
   1. recent use of nonsteroidal anti-inflammatory
      drugs.
   2. history of preprocedural antibiotic use.
   3. use of anticoagulant therapy.

   a. 1 and 2.
   b. 1 and 3.
   c. 2 and 3.
   d. 1, 2 and 3.

7. Which of the following conditions might prevent a
   patient from undergoing stereotactic biopsy?
   1. severe cough.
   2. heart failure.
   3. inability to understand informed consent.

   a. 1 and 2.
   b. 1 and 3.
   c. 2 and 3.
   d. 1, 2 and 3.

8. The lexicon for standardized mammography
   reporting is called:
   a. MQSA.
   b. CDRH.
   c. BI-RADS.
   d. OSHA.

9. According to this reporting system, a category 3
   lesion is:
   a. benign.
   b. probably benign.
   c. suspicious.
   d. highly suggestive of malignancy.

10. Which lesion is more problematic for definitive
    biopsy through the stereotactic method?
    a. ductal carcinoma in situ.
    b. atypical ductal hyperplasia.
    c. intraductal carcinoma.
    d. phyllodes tumor.

11. Which type of lesion is difficult to distinguish from
    tubular carcinoma and may not be suitable for
    needle biopsy?
    a. radial scar.
    b. sclerosing adenosis.
    c. ductal carcinoma in situ.
    d. fibroadenoma.

12. Which of the following are credited with improving
    the localization and sampling of microcalcifications
    under stereotactic technique?
    1. digital imaging.
    2. polar coordinate system.
    3. vacuum-assisted sampling.

    a. 1 and 2.
    b. 1 and 3.
    c. 2 and 3.
    d. 1, 2 and 3

13. In general, stereotactic positioning systems are
    accurate to within -- mm.
    a. 0.5.
    b. 1.
    c. 3.
    d. 5.

14. Which coordinate system defines a target based on
    3 axes that intersect at right angles?
    a. polar.
    b. BI-RADS.
    c. Z-depth.
    d. Cartesian.

15. According to the text, upright units have an
    advantage over prone units when imaging lesions
    located in:
    a. the subareolar area.
    b. the axilla or near the chest wall.
    c. large breasts.
    d. the upper inner quadrant.

16. Advantages of the dedicated prone table over an
    upright add-on unit include:
    1. lower cost.
    2. more workspace for the radiologist and
    mammographer.
    3. 360 [degrees] access to the breast.

    a. 1 and 2.
    b. 1 and 3.
    c. 2 and 3.
    d. 1, 2 and 3.

17. According to the text, which factors complicate
    imaging in stereotactic technique by increasing
    geometric blur and degrading visibility of detail?
    1. increased object-image receptor distance.
    2. reduced compression over the imaging area.
    3. increased scatter.

    a. 1 and 2.
    b. 1 and 3.
    c. 2 and 3.
    d. 1, 2 and 3.

18. With stereotactic guidance, placement of the
    lesion nearer to the skin results in:
    a. good visualization of the target lesion.
    b. increased accuracy of scout images.
    c. more room for excursion of the biopsy needle.
    d. greater patient comfort.

19. When the scout image is made, the lesion should
    be centered over the:
    a. x axis.
    b. y axis.
    c. z axis.
    d. alpha-numeric grid.

20. Advantages of digital imaging in stereotactic guidance
    include:
    1. decreased procedure time.
    2. reduced radiation exposure.
    3. improved viewing of calcifications.

    a. 1 and 2.
    b. 1 and 3.
    c. 2 and 3.
    d. 1, 2 and 3.

21. Which of the following positioning tips can help
    make a posterior lesion more accessible?
    1. place the patient's ipsilateral arm through the
       opening in the table.
    2. roll the patient into a steeper oblique position.
    3. raise the patient's ipsilateral shoulder with
       pillows.

    a. 1 and 2.
    b. 1 and 3.
    c. 2 and 3.
    d. 1, 2 and 3.

22. The average number of core samples extracted
    per mass is:
    a. 1.
    b. 3.
    c. 5.
    d. 10.

23. Percutaneous clips can be used to mark the location
    of the biopsy and do not obstruct future
    mammograms.
    a. true.
    b. false.

24. Specimen radiography is important in stereotactic
    biopsy of which type of lesion?
    a. atypical ductal hyperplasia.
    b. intraductal carcinoma.
    c. axillary masses.
    d. microcalcifications.

25. Short-term mammographic findings of air and
    hematoma occur immediately after:
    a. excisional biopsy.
    b. fine-needle aspiration.
    c. vacuum-assisted biopsy.
    d. needle localization.

26. When biopsy findings are benign, follow-up mammography
    is recommended in
    months.
    a. 3.
    b. 6.
    c. 12.
    d. 24.

27. Initial application for ACR stereotactic program
    accreditation includes:
    1. questionnaire on personnel qualifications.
    2. site visit with medical audit.
    3. submission of current quality assurance
       program details.

    a. 1 and 2.
    b. 1 and 3.
    c. 2 and 3.
    d. 1, 2 and 3.

28. The ACR accreditation program requires that
    mammographers receive -- hours of
    Category A CE in stereotactic biopsy for a facility
    to qualify for initial accreditation.
    a. 2.
    b. 3.
    c. 5.
    d. 6.

29. How often should mammographers test stereotactic
    equipment to determine localization accuracy?
    a. daily.
    b. weekly.
    c. monthly.
    d. semiannually.

30. Examples of derived data include:
    1. recall rates.
    2. cancer detection rates.
    3. false-positive rates.

    a. 1 and 2.
    b. 1 and 3.
    c. 2 and 3.
    d. 1, 2 and 3.

Reference No. DRI0001007


References

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[2.] Burbank FM. Stereotactic breast biopsy: its history, its present and its future. Am Surg. 1996;62:128-149.

[3.] Makoske T, Preletz R, Riley L, et al. Long-term outcomes of stereotactic breast biopsies. Am Surg. 2000;66:1104-1109.

[4.] Parker SH, Jobe WE, Yates WF. Breast intervention. In: Castaneda-Zuniga WR, ed. Interventional Radiology. 3rd ed. Baltimore, Md: Williams & Wilkins; 1997:1722-1743.

[5.] Liberman L. Stereotaxic biopsy technique. In: Dershaw DD. Interventional Breast Procedures. New York, NY: Churchill Livingstone Inc; 1996:107-128.

[6.] Schwartz GF, Feig SA. Management of patients with mammographically detected breast lesions. In: Marchant DJ. Breast Disease. Philadelphia, Pa: WB Saunders Co; 1997:163-177.

[7.] Kline TS. Breast. 2nd ed. Baltimore, Md: Lippincott Williams & Wilkins; 1999:253-289.

[8.] Hyser MJ, Vanuno D, Mallesh A, et al. Changing patterns of care for occult breast lesions in a community teaching hospital. Am Surg. 2000;66:438443.

[9.] Fisher PR. Problems and pitfalls in core biopsy. In: Fajardo LL, Willison LM, Pizzutiello RJ, eds. A Comprehensive Approach to Stereotactic Breast Biopsy. Cambridge, Mass: Blackwell Science Inc; 1996:73-92.

[10.] Velanovich V, Lewis FR, Hathanson SD, et al. Comparison of mammographically guided breast biopsy techniques. Ann Surg. 1999;229:625-630.

[11.] Fine R, Boyd BR. Stereotactic breast biopsy: a practical approach. Am Surg. 1996;62:96-101.

[12.] Willison KM. Overview of breast needle biopsy. In: Fajardo LL, Willison LM, Pizzutiello RJ, eds. A Comprehensive Approach to Stereotactic Breast Biopsy. Cambridge, Mass: Blackwell Science Inc; 1996:1-12.

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Teresa Norris, B.A., is a freelance writer living in northeastern New Mexico. She is a former manager of a large radiology practice and the recipient of national writing awards. Ms. Norris edits 2 national newsletters on group practice managenent and is a member of the American Medical Writers Association.

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Author:NORRIS, TERESA G.
Publication:Radiologic Technology
Geographic Code:1USA
Date:May 1, 2001
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