Breast Imaging Essentials

Transcription

1 Breast Imaging Essentials Module 8 Transcript 2017 ASRT. All rights reserved.

2 Breast Imaging Essentials Module 8 Digital Procedures and Techniques 1. ASRT Animation 2. Welcome Welcome to Module 8 of Breast Imaging Essentials Digital Procedures and Techniques. This module was written by Stephanie Johnston, M.S.R.S., R.T.(R)(M)(BD)(BS), FASRT. 3. License Agreement 4. Objectives After completing this module, you will be able to: List the requirements associated with image labeling. List the projections and positions used for mammographic imaging. Know the circumstances for using various mammographic positions. Distinguish between screening and diagnostic positions. Describe effective steps for handling special patient situations. Discuss criteria for evaluating digital mammograms. Understand localization techniques used in breast procedures. Describe various interventional breast procedures. 5. Mammographic Positioning Quality breast positioning is an art, and breasts do not come as one size fits all. It is up to the mammographer to determine the patient s habitus, to use the mammography equipment properly and to apply education and training to acquire quality mammographic images that can help detect and define breast abnormalities. Over the years, breast positioning has changed significantly, especially since the time that mammography was performed on conventional x-ray equipment. The introduction of dedicated mammography equipment with a rotating C-arm has allowed for a greater range of motion, made it easier to maneuver the breast and increased positioning possibilities. A better understanding of breast anatomy, specifically the movable and immovable aspects of the breast in conjunction with dedicated equipment, provides the mammographer a variety of positioning techniques to enhance breast images. According to the American Registry of Radiologic Technologists, women currently hold more than 99% of all mammography and breast sonography certifications. For the purposes of this module, we will assume that the mammographer is female as we discuss positioning patients for the various mammographic procedures. 6. Image Identification An essential component of breast imaging is image identification. Most of the information is input into the computer before acquiring the image. It is imperative that images are labeled correctly with the projection and laterality. Furthermore, the Mammography Quality Standards Act, or MQSA, regulations require that images include specific identification information. This information must be permanent, legible and unambiguous, and it must not obscure any patient anatomy. MQSA requirements state the image must be labeled with the patient s full name and an additional unique patient identifier, such as a medical record number. The patient s date of birth can be used as an additional identifier, but is less desirable. The label also must display the date of the examination and the facility name and location, to include the city, state, and ZIP code. If there is more than one mammography unit in the facility, a unique identifier for the unit must appear on the image.

3 The image also must indicate the laterality and mammographic view. This information must be placed near the axilla and should comply with standardized codes. Additionally, there must be an identifier for the mammographer who performed the exam, usually using her initials or a site-assigned number. Although not required by MQSA, it is also recommended to include the technical factors used for the mammogram. These factors include: target and filter, kvp, mas, degree of obliquity, compression and breast thickness. 7. Projections Mammographic positioning is divided into 3 categories: standard projections, additional projections to localize abnormalities, and additional projections to better define findings. The standard projections for mammography are the craniocaudal, or CC, and mediolateral oblique, or MLO. These two projections are used routinely in all mammography examinations. Also, these are generally the only standard projections used in screening mammography; therefore, they must be performed with the best possible positioning to show the greatest amount of breast tissue. For diagnostic mammography, several projections can be used to help localize the exact position of an abnormality in the breast. The location of an abnormality and the goal of the examination determine which projection should be used to display the abnormality. For example, if an abnormality is seen on the CC view in the outer aspect, a 90 lateral projection can help determine whether the abnormality is in the upper outer or lower outer quadrant of the breast. Finally, some projections are used to define an abnormality. Magnification and spot compression are used to clarify and characterize an abnormality. Mammographers must position standard projections to display the greatest amount of breast tissue for the interpreting physician. Then, at the radiologist's direction, the mammographer localizes or helps define the abnormality using the appropriate projection. All of these examinations assist the radiologist in determining whether there truly is an abnormality and whether the findings warrant further action. 8. C-arm The C-arm of the mammography unit can be rotated to allow the mammographer to properly position the patient for the standard and additional projections. The C-arm can move in both directions and can rotate 180. All projections are correlated with the C-arm rotation. There are standard terminology and abbreviations for each projection, and each is named according to the direction of the x-ray beam from the tube to the image receptor. Some projections fall into more than one category of localize and define. 9. Proper Breast Positioning Proper breast positioning requires knowledge of the breast s outer anatomy. The mobile borders of a normal breast are its lateral and inferior aspects. The fixed borders are the medial and superior aspects of the breast. Understanding the mobile and fixed borders of the breast allows the mammographer to adjust the mobile borders and keep from moving the compression paddle against the fixed borders. The use of compression in breast imaging is critical. Compression reduces the thickness of the breast, which decreases the dose to the patient. Compression also spreads out the breast tissue and reduces the object-to-image receptor distance, both of which make the images sharper so that it is easier to see abnormalities. Taut compression is applied in all projections to immobilize the breast. However, compressing the fixed borders can make an examination unnecessarily uncomfortable or even painful for the patient. 10. Mediolateral Oblique (MLO) The MLO projection is the best opportunity to display the most amount of breast tissue in one projection. The x-ray beam is directed from the upper-inner breast to the lower-outer breast. The C-arm angle is the most important aspect of this position and is based on the patient s habitus. For the average patient, the C-arm is positioned at about 40 to 50. Imaging tall, thin patients requires a steeper C-arm angle, usually

4 50 to 60, and imaging shorter, heavier patients requires a lesser angle, usually 30 to 40. The same angle can be used on both breasts in most patients. 11. Positioning the MLO To position the MLO projection, the mammographer angles the tube part of the C-arm 30 to 60 away from the side to be imaged and elevates the image receptor to approximately the height of the suprasternal notch. She should rotate the C-arm to the approximate angle that is appropriate for the patient s body habitus average, tall and thin, or short and heavy. This puts the image receptor at approximately the correct angle. The final angle can then be determined and any fine adjustments made. From behind the patient, the mammographer should have the patient place the hand of the side being imaged on the handlebar. Next, she should ensure that all of the breast tissue is pushed forward and that the patient is standing close to the image receptor. The mammographer then moves the medial aspect of the breast and lifts the patient s breast and pectoral muscle forward with a flat hand to visualize the lateral border. The image receptor must be parallel to the pectoral muscle of the patient. Any fine adjustments should then be made to ensure the image receptor is at the correct angle for the patient. 12. Positioning the MLO Once the angle of obliquity has been established, the mammographer should step around to check the patient s hand and position the shoulder. She should ask the patient not to squeeze the handlebar. The patient's hand should be loose, just resting on the handle with the arm draped on the top of the image receptor. This allows for optimal imaging of the pectoral muscle. The mammographer should move the patient's shoulder out of the field of view and ensure that the patient s axilla is resting on the corner of the image receptor. The patient should not move the shoulder and arm from that position. Communication is very important, and gaining the patient s cooperation during the procedure assists in acquiring optimal images. Patient communication also minimizes the number of times the mammographer must go back and forth from the mammography unit to behind the patient to reposition the shoulder. 13. Positioning the MLO The mammographer then moves back around to the medial aspect of the breast and places her thumb on the medial side of the patient s breast and her fingers on the lateral side of the patient s breast, moving the lateral border of the breast toward the fixed medial border. She then gently lifts and places the breast against the image receptor, using her opposite arm to support and keep the patient close to the image receptor. The mammographer should hold the breast upward and outward with her medial hand as she applies compression using the foot pedal. Compression should be applied so that the breast maintains the position while the mammographer removes her hand and stays in that position so there is adequate separation of the breast tissue. The breast should be taut. This combination of movements is called the up and out maneuver. If the mammographer removes her hand too soon or if inadequate compression is applied, the breast could fall, resulting in a poor image. Finally, the mammographer should pull down on the abdominal tissue under the breast to open the inframammary fold, or IMF, and she should instruct the patient to raise the chin and keep it out of the field of view. Patients should suspend respiration during exposures to minimize motion. 14. Optimal Positioning of the MLO The criteria for optimal positioning of patients for the MLO projection include: The entire breast from axilla to the inframammary fold is centered on the image receptor. No breast tissue extends beyond the margins of the image. The breast tissue is well separated. The image displays a convex pectoral muscle that is wide at the superior aspect and extends to or below the posterior nipple line. The image displays fat posterior to the fibroglandular tissue.

5 There is an open inframammary fold. The nipple is in profile. 15. Knowledge Check 16. Knowledge Check 17. Knowledge Check 18. Craniocaudal (CC) The CC projection is a standard projection used to make sure that any breast tissue missed on the MLO projection is imaged. Medial tissue is most likely to be missed, therefore it is important to demonstrate the medial tissue on the CC image, but without excessive exaggeration. As with the MLO projection, the mobile and fixed borders of the breast are used to facilitate positioning. For better control, the mammographer should position this projection from the medial side of the breast being imaged. 19. Positioning the CC To position the CC projection, the C-arm is placed at 0 and the image receptor is adjusted to a height of approximately the upper part of the patient s breast. Further adjustments can be made once the breast has been elevated. Once again, clear communication is very important to ensure the patient s cooperation during the procedure. The mammographer should instruct the patient to drop the arm of the side being imaged and relax that shoulder, placing a hand on the patient's shoulder while giving these instructions. She should then turn the patient s head toward her and away from the breast being imaged. Using the hand that is opposite from the patient s breast, the mammographer should place a flat pronated hand under the breast to elevate the breast to its highest level. Then she adjusts the image receptor to a level so that the breast can be placed on top. 20. Positioning the CC After the image receptor is adjusted, the mammographer should place her other hand on the top of the breast and gently pull the breast away from the chest wall. With one motion, the mammographer pulls the breast onto the center of the image receptor and removes her lower hand. The mammographer keeps her upper hand on the top of the breast while applying manual compression to keep the breast in place. As soon as her lower hand is free, the mammographer replaces her upper hand to hold the breast in position while making minor positioning adjustments. The patient should be rotated so the chest is against the front of the image receptor and the contralateral breast is draped over the edge. This positioning helps ensure that the medial tissue is included in the image. The nipple should be pointed forward so it will appear in profile. The mammographer should begin to apply compression with the foot control while removing the upper hand. The compression should maintain the position and adequately separate the breast tissue. The breast should be taut. The mammographer should place the patient s contralateral hand on the handlebar to keep the medial chest against the image receptor. Patients should suspend respiration during the exposure to minimize motion. 21. Optimal Positioning of the CC The criteria for optimal positioning of the CC projection include: The entire breast, from the lateral aspect to the medial aspect, is centered on the image receptor. No breast tissue extends beyond the margins of the image. The breast tissue is well separated. The posterior nipple line is within 1 cm of the MLO. Medial tissue is displayed without exaggeration. The nipple is in profile.

6 When possible, display of the pectoral muscle is at the chest wall. Visualized about 30-40% of the time. The nipple should be in profile on at least one of the standard views. The primary goal in mammography is to display the most amount of breast tissue, so mammographers should not sacrifice breast tissue for the nipple. If the nipple is not viewed in profile in at least one projection, a separate nipple in profile projection may be acquired. 22. Optimal Positioning of the CC This mammogram demonstrates all of the patient s breast tissue adequately imaged. Note the light gray area at the chest wall that represents the pectoralis muscle. The breast is evenly compressed. However, the breast tissue was not centered to the image receptor, and you can see the medial portion of the right breast in the lower corner of the image. In this mammogram, the breast tissue is centered, but there is no pectoralis muscle and breast tissue has been missed. 23. Knowledge Check 24. Knowledge Check 25. Knowledge Check Lateral Projection The most commonly used additional projection is the 90 lateral, also called a true lateral or straight lateral. This projection is used in combination with the standard projections to localize or triangulate an abnormality. The 90 lateral also is used to define calcifications known as milk of calcium. The true lateral projection can indicate whether a lesion is located in the medial, central or lateral aspect of the breast. If a lesion visualized on the MLO image appears to have moved up on the true lateral view, then the lesion is in the medial aspect of the breast. A helpful mnemonic for this is the phrase muffins rise, which emphasizes the m in medial. If the lesion visualized on the MLO projection appears to have moved down on the true lateral view, then it is in the lateral aspect of the breast. Remember the phrase lead falls for the l in lateral. Lesions that appear in approximately the same place on the MLO and true lateral projections are located centrally in the breast. The true lateral can be performed as a mediolateral or lateromedial projection, and the directional setting is based on the location of the abnormality in the breast. The goal is to achieve the shortest object-toimage receptor distance; therefore, the mediolateral or ML projection is preferred for localization of lateral abnormalities, and the lateromedial or LM projection is used for localization of medial abnormalities. 27. Positioning the ML To position the mediolateral projection, the mammographer rotates the C-arm tube away from the side to be imaged at a 90 angle and adjusts the height with the top of the image receptor approximately at the level of the suprasternal notch. Next, the mammographer should step the patient close to the image receptor and place the patient s arm on the side being imaged on the handlebar, resting the arm on top of the image receptor. The patient's shoulder should be as close as possible to the image receptor, with the corner of the image receptor posterior to the axilla. The mammographer should instruct the patient not to move the shoulder and arm from that position. The patient should bend at the waist and lean forward as if to bow to assist with positioning. With both hands holding the patient's breast, one on the lateral aspect and one on the medial, the mammographer pulls the breast medially and away from the chest wall anteriorly. When the breast is centered against the image receptor, the mammographer removes her hand from the lateral aspect; the

7 image receptor and one hand should hold the breast in position. The mammographer rotates the patient inward toward the image receptor and begins to compress with the foot control, removing the medial hand as compression is applied. The compression should maintain the position and adequately separate the breast tissue. The breast should be taut. The mammographer should pull down on the patient s abdominal tissue to open the inframammary fold. The patient should hold the contralateral breast flat and out of the imaging area with the free hand. Patients also should be instructed to suspend respiration during the exposure to minimize motion. 28. Optimal Positioning of the ML The criteria for optimal positioning of the ML projection include: The breast is centered on the image receptor. No breast tissue extends beyond the margins of the image. The breast tissue is well separated. The pectoral muscle is seen at the chest wall. Fat can be seen posterior to the fibroglandular tissue. The nipple is in profile. 29. Positioning the LM To position the lateromedial projection, the C-arm tube is rotated 90 toward the side to be imaged. The mammographer adjusts the height with the top of the image receptor approximately at the level of the suprasternal notch. The patient should step closer to the image receptor, with the image receptor between the breasts. Next, the mammographer places the patient s arm across the top of the image receptor. With both hands holding the breast, one on the medial aspect and one on the lateral, the mammographer pushes the lateral breast toward the midline while lifting up. The breast is placed against the image receptor and the mammographer removes her medial hand after making sure the breast is centered. The image receptor and one hand hold the breast in position. The patient can be rotated as needed to demonstrate the breast in a true lateral position; the mammographer begins to compress the breast with the foot control, removing the lateral hand as compression is applied. The compression should maintain the position and adequately separate the breast tissue. The breast should be taut. The mammographer then pulls down on the patient s abdominal tissue to open the inframammary fold. Instructing patients to suspend respiration during the exposure minimizes motion. 30. Optimal Positioning of the LM The criteria for optimal positioning of the LM projection include: The breast is centered on the image receptor. No breast tissue extends beyond the margins of the image. The breast tissue is well separated. The pectoral muscle can be seen at the chest wall. Fat can be seen posterior to the fibroglandular tissue. The nipple is in profile. This patient is correctly positioned for the LM projection. However, the mammographer should have used a smaller paddle because the patient has a small breast. 31. Exaggerated Craniocaudal (XCC) An exaggerated craniocaudal projection can be used to localize an abnormality not seen well in both standard projections. The exaggerated craniocaudal lateral, or XCCL, projection demonstrates more of

8 the breast's outer aspect, including most of the axillary tail. The exaggerated craniocaudal medial, or XCCM, projection demonstrates more of the inner aspect of the breast. 32. Positioning the XCC To position exaggerated craniocaudal projections, the C-arm tube is placed at 0 and elevated to approximately the upper part of the patient s breast. A 5 rotation away from the side being imaged may be used, but is not preferred. The mammographer begins positioning similarly to the CC projection by placing her flat pronated hand under the breast and elevating it to its highest level. The mammographer adjusts the image receptor to the proper level so that the breast can be placed on top of the image receptor. Next, the mammographer places her other hand on the top of the breast. With one motion, she pulls the breast onto the image receptor and rotates the patient laterally for the XCCL projection or medially for the XCCM projection, depending on the area of interest. The mammographer gently pulls the breast tissue away from the chest wall and places the breast onto the image receptor while removing her lower hand. Keeping her upper hand on the top of the breast helps the breast remain in place. As soon as the lower hand is free, the upper hand is replaced and compression with the foot control can begin. The compression should maintain the position and adequately separate the breast tissue. The breast should be taut. The patient stands with square shoulders and slightly angled laterally or medially. Instructing patients to suspend respiration during the exposure minimizes motion. 33. Optimal Positioning of the XCC The criteria for optimal positioning of the XCCL and XCCM projections include: The axillary breast tissue and pectoral muscle are displayed on the XCCL. The medial breast tissue can be seen on the XCCM. The nipple is in profile. The breast tissue is well separated. Compared to a standard craniocaudal image of the breast, the exaggerated craniocaudal lateral image displays more of the lateral tissue and less medial tissue. 34. Cleavage View (CV) The cleavage or CV projection is used to localize abnormalities in the posteromedial aspect of the breast. It may be called the valley or double breast compression projection. This view demonstrates the medial aspect of both breasts and the area between the breasts. 35. Positioning the CV To position the cleavage projection, the C-arm tube is placed at 0 and elevated to approximately the upper part of the patient s breast. The mammographer may position a patient from behind for this projection if she is able to wrap her arms around the patient and place both of the patient s breasts on the image receptor. However, to make sure that the area of interest is localized, positioning from one side may be easier. Both breasts and the inframammary fold should be elevated and gently pulled anteriorly while placing the patient s breasts on the image receptor. Depending on the technique selected to expose the image, positioning a bit off center allows breast tissue to cover the detector for automatic exposure control, or AEC, exposures. If a manual technique is used, the cleavage may be centered on the image receptor with the medial aspect of both breasts spaced equally. While holding the breast tissue away from the chest wall, the mammographer begins compression with the foot control, removing her hand as the compression is applied. The compression should maintain the position and adequately separate the breast tissue. The compressed part of the breasts should be taut. The patient should suspend respiration during the exposure to minimize motion.

9 36. Optimal Positioning of the CV The criteria for optimal positioning of the cleavage view include: The cleavage area of interest is displayed on the image receptor. The breast tissue is well separated. 37. Axillary Tail (AT) The axillary tail or AT projection is used to localize or define abnormalities in the lateral aspect of the breast. This projection can show the entire axillary tail and most of the lateral breast tissue. Because this projection concentrates on the lateral aspect of the breast, the medial breast tissue is not a significant consideration for positioning. 38. Positioning the AT To position the axillary tail projection, the mammographer rotates the C-arm tube away from the breast to an angle that places the image receptor parallel to the axillary tail. This angle is not the same as the angle used for the MLO projection. Once the angle of obliquity has been determined, the patient gently rests the hand of the side being imaged on the handlebar. The hand should be loose, just resting on the handle with the arm draped on top of the image receptor. The mammographer places one hand laterally on the breast and one hand medially over the breast, gently pulling the axillary region and lateral part of the breast inward. The lateral hand is removed as the tail of the breast is placed on the image receptor. As soon as the lateral hand is free, the mammographer replaces the medial hand to hold the breast in position while making minor positioning adjustments. While holding the breast in place with the other hand, she can begin compression with the foot control and remove her hand as the compression is applied. The compression should maintain the position and adequately separate the breast tissue. The compressed part of the breast should be taut. Instructing patients to suspend respiration during the exposure minimizes motion. 39. Optimal Positioning of the AT The criteria for optimal positioning of the axillary tail include: The axillary tail and pectoral muscle are seen on the image. The breast tissue is well separated. 40. Knowledge Check 41. Knowledge Check 42. Tangential (TAN) Projection The tangential or TAN projection can be used in two different ways. First, it can help define palpable lesions that are obscured by dense glandular tissue. By using a tangential view, the area of interest can be displaced over subcutaneous fat where it is more distinguishable from surrounding tissue. Secondly, the tangential projection can be used to localize calcifications located in the skin. A marker such as a BB usually is used when performing the tangential projection. 43. Positioning the TAN Projection To position the tangential projection for a palpable abnormality, the mammographer first places a BB marker directly over the palpable area. Once the area is marked, the breast is rotated to move the palpable nodule until it is tangential to the C-arm. The C-arm may need to be rotated to accommodate this position. The shadow of the BB can be seen on the image receptor if positioning is correct. The mammographer begins compression with the foot control while holding the breast in the correct position, removing her hand as the compression is applied. The compression should hold the breast in position, and the compressed part of the breast should be taut. Patients should suspend respiration during the exposure to minimize motion.

10 44. Marking Calcifications Before positioning the patient for a tangential projection for calcifications, the calcifications must be visualized and marked. This is performed using a localization paddle with radiopaque alphanumeric indicators or holes. The mammographer should know the general location of the calcifications, such as lateral vs medial or superior vs inferior, in order to position the patient in the localization paddle with the area of interest closest to the paddle. For calcifications on the superior aspect of the breast, the patient is placed in the CC position. For calcifications on the lateral aspect, the patient is positioned in the LM position, and so on. When the position is determined, the automatic compression release must be turned off. The compression paddle needs to hold the breast in place until the image is evaluated. The alphanumeric crossing or closest hole over the calcification is determined from the image, and a BB marker is placed on the patient s skin over that area. The mammographer then releases compression, making sure the marker is not disturbed. 45. Positioning the TAN View for Calcifications Once the area has been marked, the breast is rotated to move the BB tangential to the C-arm. The C-arm may need to be rotated to accommodate this position. The shadow of the BB should be seen on the image receptor if the position is correct. The mammographer begins compression with the foot control while holding the breast in the correct position, removing her hand as the compression is applied. The compression should hold the breast in position, and the compressed part of the breast should be taut. Patients should suspend respiration during the exposure to minimize motion. 46. Optimal Positioning of the TAN Projection The criteria for optimal positioning of tangential views include: The mammographer places a BB marker at the skin line over the palpable abnormality or calcifications. The area of interest is displayed on the image. The breast tissue is well separated. 47. Rolled Projections The rolled projections can be used in several circumstances, such as helping to separate breast tissue that is superimposed or assisting in locating an abnormality only displayed in one standard projection. Rolled images also can help confirm that an abnormality is present or better define it. The rolled projections are rolled lateral, or RL; rolled medial, or RM; rolled superior, or RS; and rolled inferior, or RI. Rolled projections require carefully rolling the breast along its x-axis in a sort of twisting motion to change the position of inner tissue. Doing so requires attention to labeling of the projection and rolling technique to further aid the radiologist in understanding the tissue and lesion displacement. 48. Positioning the RL and RM It is important for the mammographer to know the general location of the abnormality before rolling or compressing the breast. To position the RL and RM projections, the C-arm tube is placed at 0 and the image receptor is at the level of the upper breast. A radiopaque BB marker is placed on the superior aspect of the breast. This is only used as a reference, so the BB placement does not have to be precise. The mammographer positions the patient exactly as for a CC examination, with her pronated hand lifting the breast and the other on top pulling it away from the chest wall. Before removing her lower hand, the mammographer rolls the breast. To roll laterally, the mammographer pushes the top of the breast away (laterally) while pulling the bottom toward her (medially). To roll medially, the mammographer pulls the top of the breast toward her (medially) and rolls the bottom of the breast away (laterally). As soon as the breast is rolled, the mammographer removes her lower hand and places the breast on the image receptor without moving the breast from its rolled position. She replaces her upper hand with the free hand to hold the breast in position while beginning compression with the foot control. The mammographer applies enough compression to hold the breast in the rolled position. The

11 compression should maintain the position and adequately separate the breast tissue. The breast should be taut. Patients should suspend respiration during the exposure to minimize motion. The breast usually is rolled and imaged in both the lateral and medial directions. The mammographer performs either the RL or RM, and releases compression to return the breast to a neutral position before rolling the breast in the opposite direction. The radiopaque BB marker moves with the direction of the roll. It is important to mark the projection correctly with the roll of the breast. 49. Optimal Positioning of the RL and RM The criteria for optimal positioning of rolled lateral and rolled medial views include: The area of interest is displayed on the image. The breast tissue is well separated. The BB marker is displaced laterally and medially. 50. Positioning the RS and RI Usually, an abnormality seen only on the MLO or true lateral images can be seen more clearly using RS and RI projections. Once the mammographer knows the general location of the breast abnormality, the C- arm tube is rotated to 90 and the image receptor is placed at the level of the suprasternal notch. The mammographer places a radiopaque BB marker on the medial aspect of the breast. The BB is only used as a reference, so its placement does not have to be precise. The mammographer positions the patient exactly as if acquiring a true lateral image. The patient steps close to the image receptor, with the arm of the side being imaged on the handlebar, resting on top of the image receptor. With both hands holding the breast, one on the lateral aspect and one on the medial, the mammographer pulls the breast medially and away from the chest wall anteriorly. Before removing the lower hand, the mammographer rolls the breast. To roll superiorly, the mammographer pushes the medial aspect of the breast up (superiorly) and pulls the lateral aspect of the breast down (inferiorly). To roll inferiorly, the mammographer pulls the medial aspect of the breast down (inferiorly) and pushes the lateral aspect of the breast up (superiorly). As soon as the breast is rolled, the mammographer removes her lower hand and places the breast against the image receptor without moving the breast from its rolled position. The mammographer holds the breast with the medial hand and begins compression with the foot control, applying enough compression to hold the breast in the rolled position. The compression should maintain the position and adequately separate the breast tissue. The breast should be taut. Patients should suspend respiration during the exposure to minimize motion. The breast usually is rolled and imaged in both the inferior and superior directions. The mammographer performs either the RS or RI, and releases compression to return the breast to a neutral position before rolling the breast in the opposite direction. The radiopaque BB marker moves with the direction of the roll. It is important to mark the projection correctly with the roll of the breast. 51. Optimal Positioning of the RS and RI The criteria for optimal positioning of rolled superior and rolled inferior views include: The area of interest is displayed on the image. The breast tissue is well separated. The BB marker is displaced superiorly and inferiorly. 52. Caudocranial Projection (FB) The caudocranial projection, also called from below, FB or reverse CC, can help define abnormalities in the upper region of the breast because the object-to-image receptor distance is reduced. Also, the FB projection can be used during needle localizations or core biopsy procedures if the shortest distance to a lesion is from the inferior aspect. This projection also can be used for imaging of the male breast or for

12 patients with kyphosis. Because it works against the fixed superior border of the breast, the FB projection is a little more difficult to position and more uncomfortable for the patient. 53. Positioning the Caudocranial (FB) To position the FB projection, the mammographer rotates the C-arm tube 180 and raises the image receptor to the level of the upper breast. The patient may have to place a leg on each side of the tube. The mammographer positions the patient from the medial aspect of the patient, placing a flat, pronated hand under the patient's breast and elevating the breast to its highest level. The image receptor is adjusted so that it is level to the superior border of the breast. The mammographer places her other hand on top of the breast and gently pulls the breast inferiorly away from the chest wall. With one motion, the mammographer pulls the breast onto the image receptor, making sure that the breast is centered and the nipple is straight out. The mammographer places the superior aspect of the breast against the image receptor and removes her upper hand. The mammographer begins to apply compression with the foot control while holding the inferior breast in position, then removes her lower hand as the compression is applied. The compression should maintain the position and adequately separate the breast tissue. The breast should be taut. Instructing patients to suspend respiration during the exposure minimizes motion. 54. Optimal Positioning of the Caudocranial (FB) The criteria for optimal positioning of the FB projection include: The entire breast from lateral aspect to medial aspect should be centered on the image receptor. No breast tissue extends beyond the margins of the image. No evidence of blur or motion. Breast tissue is well separated. If possible, the posterior nipple line is within 1 cm of the MLO image. However, this may not be attainable because of the fixed borders of the breast. The medial tissue is displayed without exaggeration. The nipple is in profile. If possible, visualization of the pectoral muscle at the chest wall. However, this may not be attainable because of the fixed borders of the breast. 55. Lateromedial Oblique (LMO) The lateromedial oblique or LMO projection, also called the true reverse MLO, can help define abnormalities in the medial aspect of the breast because the object-to-image receptor distance is reduced. In this projection, the beam is directed from the lower-outer breast to the upper-inner breast, which is exactly opposite of the MLO projection. The LMO projection also can be used for a patient who has a sunken chest or who recently has undergone open heart surgery. It also may be a more comfortable position for patients who have prominent pacemakers. 56. Positioning the LMO To position the LMO projection, the C-arm tube is angled 110 to 130, and the x-ray beam will enter the breast tissue from the inferolateral to the superomedial aspect. The image receptor should be placed on the medial aspect of the breast and elevated to the height where the breast will be centered. The patient s arm of the side being imaged is flexed and placed across the top of the image receptor, resting on the unit. The patient cannot hold on to the handlebar in this position. The mammographer should gently pull the breast up and out from the chest wall with one hand placed medially and the other laterally. Then, she should place the medial aspect of the breast against the image receptor while removing her lower hand. The upper hand is replaced while holding the breast in place. The mammographer should adjust the patient's position to make sure the breast and pectoral muscle are imaged. The mammographer begins compressing with the foot control while holding the breast in the correct position, removing her hand as the compression is applied. The compression should maintain the

13 position and adequately separate the breast tissue. The breast should be taut. Pulling the abdominal tissue under the breast opens the inframammary fold. Instructing the patients to suspend respiration during the exposure minimizes motion. 57. Optimal Positioning of the LMO The criteria for optimal positioning of the LMO projection include: The entire breast from axilla to inframammary fold should be centered on the image receptor. No breast tissue extends beyond the margins of the image. Breast tissue is well separated. The convex pectoral muscle is wide at the superior aspect and extends to or below the posterior nipple line. Fat is seen posterior to the fibroglandular tissue. The inframammary fold is open. The nipple is in profile. 58. Knowledge Check 59. Knowledge Check 60. Superolateral-to-Inferomedial Oblique (SIO) The superolateral-to-inferomedial oblique, or SIO, projection can help define abnormalities in the medial aspect of the breast because the object-to-image receptor distance is reduced. In this projection, the x- ray beam is directed from the upper-outer breast to the lower-inner breast, or opposite from the LMO projection. The SIO projection has mistakenly been called a reverse oblique. This projection is not very practical and can be difficult to position. 61. Positioning the SIO To position a patient for an SIO image, the C-arm tube is rotated 40 to 50 toward the side to be imaged and raised to the level of the suprasternal notch. The arm on the side to be imaged is placed over the face shield and draped on the top of the image receptor. The front of the image receptor is situated between the breasts. Compression should be applied to maintain the position and adequately separate the breast tissue. The breast should be taut. Patients should suspend respiration during the exposure to minimize motion. 62. Optimal Positioning of the SIO Criteria for optimal positioning of the SIO view include: The breast should be centered on the image receptor. No breast tissue extends beyond the margins of the image. No evidence of blur or motion. Breast tissue is well separated. The nipple is in profile. 63. Augmented Breast Exams The augmented breast can be a challenge both for the mammographer and the radiologist. The mammographer must acquire adequate information for the radiologist s interpretation. For this reason, additional images of the augmented breast are required. Usually the examination includes the standard CC and MLO projections with the implant included, and modified CC and MLO views with the implant displaced. Since the implant displaced, or ID, projections are performed in the CC and MLO positions, in most situations a total of 8 images comprise the augmented breast study. In some instances, a 90 lateral image might be added. As with other patients' breasts, augmented breasts are not all alike. Subpectoral implants are placed under the pectoralis muscle, and subglandular implants are placed in front of the pectoralis muscle, between the breast tissue and muscle. Some patients may have ample breast tissue to display on the ID

14 projection, but others may have very little breast tissue. For patients with very little breast tissue, the implant may not be adequately displaced. In this case, the 90 lateral implant-included projection should be performed along with the implant-included CC and MLO projections, making the exam complete with 6 images. 64. Augmented Breast Imaging The standard implant-included projections require use of a manual technique and compression limited to the stiffness of the implant. Firm implants require less compression and soft implants require more. The purpose of the compression on the implant-included view is to hold the breast in position so that as much of the implant and surrounding breast tissue as possible can be clearly demonstrated without motion. Extreme compression could cause damage to the implant. The implant-displaced projections pull the breast tissue anteriorly and displace the implant posteriorly and superiorly; sufficient compression is used to separate the breast tissue. 65. Positioning the Implant To position the implant-included CC and MLO views, the mammographer uses the same positioning technique as the standard CC and MLO views. At the point where compression is applied, the mammographer uses the foot control to compress the breast and implant only enough to make sure that the breast stays in position. A manual technique is used to image the implant-included views, and the patient should suspend respiration during the exposure. 66. Displaced CC Projection To position the implant-displaced CC projection, the mammographer should stand on the medial side of the breast being imaged. With the patient standing in front of the image receptor, the mammographer adjusts the height to approximately the upper part of the patient s breast. Fine adjustments can be made once the breast has been elevated and pulled anteriorly away from the implant. One hand is placed on the superior aspect and the other on the inferior aspect of the breast. Using the fingers of both hands in a kneading motion, the mammographer pulls the breast tissue forward while pushing the implant back. In most cases, the implant can be felt in the breast tissue. The breast is elevated with both hands as done for the CC view. The mammographer instructs the patient to move forward to the image receptor and places the inferior aspect of the breast on the image receptor while removing the lower hand. The edge of the image receptor holds the implant back and the upper hand should still be in place superiorly, holding the breast tissue out and the implant back. The mammographer uses the foot control to apply compression while removing the upper hand. Adequate compression is applied to hold the implant back and spread out the anterior breast tissue. The breast should be taut. Instruct the patient to suspend respiration during the exposure. 67. Displaced MLO Projection To position the implant-displaced MLO projection, the mammographer rotates the C-arm tube until it is angled 30 to 60 away from the side to be imaged. The mammographer adjusts the height of the image receptor to center the breast on the image receptor with the patient standing in front of it. Fine adjustments can be made once the breast has been elevated and pulled anteriorly away from the implant. One hand is placed on the lateral aspect and the other on the medial aspect of the breast. Using the fingers of both hands in a kneading motion, the mammographer pulls the breast tissue forward while pushing the implant back. Again, the implant usually can be felt in the breast tissue. The patient moves forward to the image receptor and the mammographer places the lateral aspect of the breast on the image receptor while removing her lower hand. The edge of the image receptor holds the implant back and the upper hand should still be in place medially, holding the breast tissue out and the implant back. The mammographer uses the foot control to apply compression while removing her upper hand. Adequate compression is applied to hold the implant back and spread out the anterior breast tissue. The breast should be taut. Instruct the patient to suspend respiration during the exposure. 68. Optimal Positioning of the CC and MLO Implant-Included The criteria for optimal positioning of the CC and MLO implant-included projections include:

15 The entire breast should be centered on the image receptor. No breast tissue should extend beyond the margins of the image. There is no evidence of blur or motion. There is inadequate separation of breast tissue due to the reduced amount of compression. The nipple is in profile. The implant should be visible at the chest wall. 69. Optimal Positioning of the CC and MLO ID The criteria for optimal positioning of the CC and MLO implant-displaced views include: The breast centered on the image receptor. No breast tissue extends beyond the margins of the image. The breast tissue is well separated. The nipple is in profile. The pectoral muscle is visible at the chest wall if the implant is subpectoral. 70. Spot Compression Spot compression is used to define specific areas of abnormalities identified on standard mammography images. There are a variety of spot compression and contact paddles that can be used with the standard image receptor or magnification attachments. The paddles reduce the thickness of the area of interest and improve separation of tissue. The smaller the spot compression paddle, the more effective the localized compression should be. Localizing a specific area in the breast with spot compression results in a higher contrast image. To determine the location of the abnormality to spot compress, the mammographer must triangulate the location using the original mammogram. On the images, the mammographer draws a straight line from the nipple to the back of the image. Next, the mammographer draws a perpendicular line that dissects the lesion and meets the closest edge of the skin line and the first line. In the CC view, if the abnormality is in the lower aspect of the breast, a line is drawn to the medial border, and if the abnormality is in the upper aspect of the breast, a line is drawn to the lateral border. In the MLO view, if the abnormality is in the upper aspect, the mammographer draws a line to the superior border, and if the abnormality is in the lower aspect of the breast, a line is drawn to the inferior border. 71. Positioning the Spot Compression Once the area has been triangulated, the mammographer can acquire a spot compression image. The appropriate spot compression paddle is positioned directly over the area of interest. The mammographer compresses the breast to hold it in position and adequately separate the breast tissue. Because the entire breast is not compressed, the breast will not be taut. Spot compression images generally are acquired in two different planes, such as CC and MLO, or CC and ML. The criteria for optimal positioning of spot compression projections include: The area of interest is centered in the spot compression paddle. There is adequate separation of breast tissue to allow display of abnormalities. 72. Magnification Magnification can be used with or without spot compression. The purpose of magnification is to display the margins and architectural characteristics of a density or mass and delineate calcification characteristics such as number, distributions and morphology. Spot compression magnification is particularly beneficial because it compresses the indicated area and magnifies it at the same time, giving the radiologist an image with clearer definition of an abnormality. The magnification platform increases the distance between the compressed breast and the image receptor, resulting in 1.5 to 2 times magnification. Use of magnification requires a smaller focal spot and thus a longer exposure time. It is important to have the patient remain very still during the exposure.