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Breast Imaging: From 1965 to the Present¹

¹ From the Department of Radiology, University of California Medical Center, 2330 Post St, Room 180, San Francisco, CA 94115. Received August 31, 1999; revision requested October 12; revision received November 4; accepted November 12. Address reprint requests to the author.

Abstract

The current state of the art for breast imaging is reviewed in comparison with the methods of practice commonly in use 25–35 years ago to demonstrate the most important advances that have taken place in imaging techniques, operational considerations, interpretive approaches, and interventional procedures. Since 1965, breast imaging has progressed from the simple assessment of breast disease in a selected small number of symptomatic women to the comprehensive evaluation of both breast health and disease in a substantial percentage of all women aged 40 years and older. In the process, breast imaging has become an established radiologic subspecialty that accounts for at least 10% of all examinations performed by radiologists. Indeed, mammography now is the most common imaging examination that directly results in the reduction of mortality from disease.

Index terms: Breast, diseases • Breast neoplasms, 00.3 • Radiology and radiologists, history • Reflections

Over the past 35 years, the practice of breast imaging has experienced a wide variety of technologic, procedural, interpretive, and interventional advances, in addition to a series of regulatory requirements, all of which have contributed to the creation of a greatly improved and far more effective set of imaging tools to permit the reliable detection and diagnosis of breast disease.

In this article, I will review what it was like to conduct a breast imaging practice as far back in time as I can reconstruct from memory and available personal records, as well as how the practice of breast imaging has changed from then to now. I will do this not only in text but also by providing both past and current illustrations of several common breast lesions encountered in day-to-day practice, to demonstrate the most important advances since 1965 in the imaging, the radiologic work-up, and the management of breast disease. For those readers who have personal recollections of the earlier days of breast imaging, this trip down memory lane likely will induce some reflections on times past. However, all readers, regardless of previous experience, should gain a greater appreciation of the extensive advances in breast imaging practice that have taken place over the past several decades.

OPENING THE TIME CAPSULE: BREAST IMAGING PRACTICE 25–35 YEARS AGO

In July 1975, when I began to conduct and interpret breast imaging studies, virtually all such activity involved x-ray mammography (some enthusiasts also performed thermography, an indirect method to depict the surface temperature of the breast). I had just completed a residency in diagnostic radiology, and as the most junior staff radiologist in the practice, I was assigned to mammography because the two previous mammographers had just resigned and because all of the other radiologists declined to assume the responsibility for interpreting mammograms. I had not planned a subspecialty career in breast imaging. How could one envision success in a field that most other radiologists avoided so scrupulously, especially with a caseload that had averaged only five examinations per day? However, a major redeeming aspect of my new job was that as the only mammographer in my practice, I rapidly became indispensable, albeit underemployed, in that capacity.

I was fortunate to have inherited from my predecessors a fairly extensive collection of pathology-proved teaching file cases, spanning the previous 10 years of mammographic experience. It is from careful study of these cases that I am able to reconstruct the state of breast imaging practice dating back to 1965, and it is also from these cases that I have chosen many of the illustrations used in this article.

I had received no breast imaging training at all during residency. Like most of the few other radiologists who read mammograms at that time, I acquired my training "on the job," prefaced by diligent cover-to-cover reading of several now classic textbooks (1–4) and attendance at a 1-week postgraduate course taught at a major university medical center. Energized by the enthusiasm of a neophyte and unconcerned about the then inconsequential level of malpractice exposure, I gradually learned my trade.

In 1975, most mammography was performed with a ceiling-mounted general-purpose x-ray tube powered by a generator specially adapted to produce low-kilovoltage exposures (35–40 kVp), which were recorded either on direct-exposure film or with xeroradiography, an imaging technique adapted from the xerographic photocopying process. In addition to the performance of these standard types of mammography, my practice had acquired a specialized breast x-ray unit (dedicated to the performance of mammography) that introduced two important technologic advances: a molybdenum-anode x-ray tube and built-in uniform-thickness breast compression (5). We used this new equipment in conjunction with the first commercially available mammographic screen-film system (single-emulsion film coupled with a single radiographic screen), which permitted imaging with shorter, lower-dose exposures that were less subject to degradation by motion blur (6).

Encouraging results had recently been published from the landmark Health Insurance Plan of Greater New York randomized clinical trial of breast screening with mammography and clinical examination; these results showed a statistically significant reduction in breast cancer deaths among women offered screening, compared with a control group of women who were not offered screening (7). This had prompted the National Cancer Institute and the American Cancer Society to begin a widely publicized large-scale multi-institutional Breast Cancer Detection Demonstration Project (8,9). Breast cancers also had recently been detected in the wives of President Ford and Vice President Rockefeller, which further heightened public awareness of breast disease and the potential value of mammography.

Nevertheless, in 1975, little mammographic screening was being performed as usual care in the United States. In my practice, almost all women undergoing mammography had signs or symptoms of breast disease, most commonly involving the chance self-discovery of a palpable mass, usually measuring 2 cm or larger in diameter. Many of these were young women; in my practice, at least 25% were younger than 40 years of age.

The mammographic features of cancer and many benign lesions had been known for years, derived principally from experience with large palpable masses. However, because mammographic diagnoses were not definitive and because there were no other reliable diagnostic tests, subsequent management in the great majority of cases involved excisional biopsy, a practice that resulted in the removal of several benign lesions (usually cysts and fibroadenomas) for each cancer discovered (10). The surgeon commonly would request intraoperative frozen-section histologic analysis of any lesion judged to be suspicious for malignancy at gross inspection; such analysis was often followed by immediate mastectomy if the diagnosis of carcinoma was confirmed.

Occasionally, a clinically occult lesion was detected at mammography that raised some suspicion of malignancy. However, the subsequent management of such a lesion often was problematic because it was difficult to excise a lesion that in most cases was nonpalpable even in retrospect. Usually, the surgeon chose to resect a major portion of the breast quadrant described by the radiologist in the mammographic report. The alternative procedure, which was performed principally to maximize the likelihood of including the questionable lesion in the resected tissue, involved preoperative mammographic localization (11,12). This was accomplished with the freehand insertion of a needle into the general region of the questionable lesion, with verification of satisfactory needle position with mammography, after which the patient was taken promptly to the operating room, with the needle taped to the skin of the breast.

TODAY'S TIME CAPSULE: BREAST IMAGING AT PRESENT

Almost every aspect of breast imaging has undergone major changes in the past 25–35 years. Screen-film mammography has completely replaced imaging with direct-exposure film and xeroradiography. Both the contrast and resolution of conventional film images have increased considerably because of improvements in x-ray tubes, breast-compression devices, radiographic screens, film, and the introduction of reciprocating grids. Deeper portions of the breast now are included routinely in the image field because of improvements in the design of dedicated mammography units, the introduction of the mediolateral oblique (MLO) view to the standard imaging protocol (13), the development of effective methods to teach positioning of the breast during mammography (14), and the recruitment of a large number of well-trained technologists who specialize in mammography. New mammographic techniques also have been developed to portray screening-detected lesions with greater clarity, including magnification views (15,16), spot-compression views (17,18), roll views (19), and implant-displaced views (20).

The routine use of mammographic screening has become much more widespread, primarily because of favorable results from multiple randomized controlled trials and the development of improved methods of preoperative needle localization. A larger percentage of radiologists now interpret mammograms, with daily caseloads having increased in many practices to 50 or more examinations per day. Screening examinations currently account for more than 75% of all mammography performed in the United States, and as a result, the majority of detected lesions, both benign and malignant, are small and nonpalpable. In most general radiology practices, mammography accounts for at least 10% (sometimes as much as 20%) of all examinations performed.

Breast imaging also has become an established radiologic subspecialty, which is now taught in all residency training programs and included in the written and oral certification examinations of the American Board of Radiology. Some radiologists even choose to acquire an extra year of postgraduate fellowship training in breast imaging, in preparation for full-time or majority-time breast imaging practice. The Society of Breast Imaging has become one of the largest radiologic subspecialty organizations in the United States, with almost 2,000 members.

The widespread use of mammographic screening in asymptomatic women, coupled with a high level of general awareness of breast cancer as a public health problem, has prompted a series of governmental regulations that affect mammography, both at state and federal levels (21,22). These regulations, although costly, also have resulted in an overall improvement in the quality of mammographic images (23) and, because of the imposition of initial-education, continuing-education, and continuing-experience requirements for radiologists, probably an improvement in the quality of mammographic interpretation as well (24).

During the past several decades, substantial advances have been made in nonmammographic breast imaging techniques. Ultrasonography (US) has been found to reliably characterize simple cysts if rigorous interpretive criteria are used, thereby avoiding tissue diagnosis for these common, invariably benign lesions (25–27). In addition, several sonographic features have been identified that are sufficiently suggestive of malignancy to prompt biopsy (which often results in cancer diagnosis), even in the absence of suspicious findings at mammography or clinical breast examination (28–30). These are major reasons why US has become an integral part of modern breast imaging practice, although it has not yet been shown to be effective for screening asymptomatic women (31–34).

Magnetic resonance (MR) imaging also can be used to make valuable contributions to the diagnosis and management of breast disease. MR imaging is the most accurate noninvasive examination to evaluate the integrity of silicone-filled breast implants (35), and because of its high sensitivity, MR imaging appears to be more effective than either mammography or US in assessing for multifocal and multicentric tumor in patients with a known primary carcinoma (36,37), an important consideration because most cancers now are treated with breast preservation rather than mastectomy.

Several major advances have involved imaging-guided breast interventional procedures, which now permit more accurate and less invasive approaches to tissue diagnosis. Needle placement during preoperative mammographic localization can now be done more rapidly and with greater precision by using specially designed fenestrated breast-compression paddles, and a variety of hooked wires have been developed, which anchor in breast tissue after deployment through the localizing needle (38).

Highly accurate procedures for performing percutaneous tissue diagnosis also have been developed, with either sonographic or stereotactic mammographic guidance. Coupled with either fine-needle aspiration or core biopsy, these approaches allow for reliable diagnosis of most benign lesions without the need for surgical resection, thereby reducing morbidity and cost (39–44). Furthermore, the percutaneous diagnosis of malignancy prior to open surgery often permits the delivery of definitive surgical treatment in a streamlined and also less costly manner (45–47).

ILLUSTRATIONS OF HOW BREAST IMAGING HAS CHANGED FROM 25–35 YEARS AGO

I have chosen to illustrate the changes in breast imaging that have taken place over the past several decades by presenting a series of matched then-and-now cases involving commonly encountered mammographic lesions. When considered in the light of current (greatly superior) imaging standards, it seems improbable that the mammography of 25–35 years ago could have served any useful clinical role at all because even the best of older images would now be judged to be unacceptable in quality. However, judged in the context of the typical large and palpable lesions encountered in everyday practice at that time, one can understand why mammography then actually did enjoy a modicum of success. On the other hand, the much greater success of modern breast imaging is directly related to the many technologic, procedural, interpretive, and interventional advances that I have already described.

Standard Negative Examination
In the 1965–1975 period, the amount of breast tissue close to the chest wall that was included in the mammographic image field varied greatly with the type of equipment used. Images also were relatively low in contrast and clearly depicted the skin and subcutaneous tissues but often showed little difference in opacity between areas of dense fibroglandular tissue and fatty lobules within the parenchyma (Fig 1).

View larger version (63K): [in this window] [in a new window] [Download PPT slide]   Figure 1a. Standard negative mammograms: 1965-1975. Standard examination included a 90° lateral and craniocaudal (CC) view of each breast. (a) Lateral and (b) CC direct-exposure film mammograms. There was only slight (if any) compression of the breast during exposure, which impaired depiction of tissues close to the chest wall because the x-ray beam could not effectively penetrate these thicker regions of the breast without grossly overexposing the thinner regions close to the nipple. (c) Lateral and (d) CC xeromammograms. The wide latitude of the xeroradiographic imaging process overcame the previously described limitation of direct-exposure film mammography. However, the perceived need to include chest wall structures in the image field on the 90° lateral view compromised the detail of these images, because this required placement of a sponge between the breast and imaging cassette to permit use of gentle compression. (e) Lateral and (f) CC screen-film mammograms. This imaging technique was coupled with the use of a dedicated molybdenum-anode x-ray unit that provided uniform-thickness breast compression so that both thick and thin regions of the breast were properly exposed in the image. However, the combination of uniform-thickness breast compression and the use of the 90° lateral projection limited the amount of posterior tissues included in the image field.

View larger version (44K): [in this window] [in a new window] [Download PPT slide]   Figure 1b. Standard negative mammograms: 1965-1975. Standard examination included a 90° lateral and craniocaudal (CC) view of each breast. (a) Lateral and (b) CC direct-exposure film mammograms. There was only slight (if any) compression of the breast during exposure, which impaired depiction of tissues close to the chest wall because the x-ray beam could not effectively penetrate these thicker regions of the breast without grossly overexposing the thinner regions close to the nipple. (c) Lateral and (d) CC xeromammograms. The wide latitude of the xeroradiographic imaging process overcame the previously described limitation of direct-exposure film mammography. However, the perceived need to include chest wall structures in the image field on the 90° lateral view compromised the detail of these images, because this required placement of a sponge between the breast and imaging cassette to permit use of gentle compression. (e) Lateral and (f) CC screen-film mammograms. This imaging technique was coupled with the use of a dedicated molybdenum-anode x-ray unit that provided uniform-thickness breast compression so that both thick and thin regions of the breast were properly exposed in the image. However, the combination of uniform-thickness breast compression and the use of the 90° lateral projection limited the amount of posterior tissues included in the image field.

View larger version (97K): [in this window] [in a new window] [Download PPT slide]   Figure 1c. Standard negative mammograms: 1965-1975. Standard examination included a 90° lateral and craniocaudal (CC) view of each breast. (a) Lateral and (b) CC direct-exposure film mammograms. There was only slight (if any) compression of the breast during exposure, which impaired depiction of tissues close to the chest wall because the x-ray beam could not effectively penetrate these thicker regions of the breast without grossly overexposing the thinner regions close to the nipple. (c) Lateral and (d) CC xeromammograms. The wide latitude of the xeroradiographic imaging process overcame the previously described limitation of direct-exposure film mammography. However, the perceived need to include chest wall structures in the image field on the 90° lateral view compromised the detail of these images, because this required placement of a sponge between the breast and imaging cassette to permit use of gentle compression. (e) Lateral and (f) CC screen-film mammograms. This imaging technique was coupled with the use of a dedicated molybdenum-anode x-ray unit that provided uniform-thickness breast compression so that both thick and thin regions of the breast were properly exposed in the image. However, the combination of uniform-thickness breast compression and the use of the 90° lateral projection limited the amount of posterior tissues included in the image field.

View larger version (86K): [in this window] [in a new window] [Download PPT slide]   Figure 1d. Standard negative mammograms: 1965-1975. Standard examination included a 90° lateral and craniocaudal (CC) view of each breast. (a) Lateral and (b) CC direct-exposure film mammograms. There was only slight (if any) compression of the breast during exposure, which impaired depiction of tissues close to the chest wall because the x-ray beam could not effectively penetrate these thicker regions of the breast without grossly overexposing the thinner regions close to the nipple. (c) Lateral and (d) CC xeromammograms. The wide latitude of the xeroradiographic imaging process overcame the previously described limitation of direct-exposure film mammography. However, the perceived need to include chest wall structures in the image field on the 90° lateral view compromised the detail of these images, because this required placement of a sponge between the breast and imaging cassette to permit use of gentle compression. (e) Lateral and (f) CC screen-film mammograms. This imaging technique was coupled with the use of a dedicated molybdenum-anode x-ray unit that provided uniform-thickness breast compression so that both thick and thin regions of the breast were properly exposed in the image. However, the combination of uniform-thickness breast compression and the use of the 90° lateral projection limited the amount of posterior tissues included in the image field.

View larger version (65K): [in this window] [in a new window] [Download PPT slide]   Figure 1e. Standard negative mammograms: 1965-1975. Standard examination included a 90° lateral and craniocaudal (CC) view of each breast. (a) Lateral and (b) CC direct-exposure film mammograms. There was only slight (if any) compression of the breast during exposure, which impaired depiction of tissues close to the chest wall because the x-ray beam could not effectively penetrate these thicker regions of the breast without grossly overexposing the thinner regions close to the nipple. (c) Lateral and (d) CC xeromammograms. The wide latitude of the xeroradiographic imaging process overcame the previously described limitation of direct-exposure film mammography. However, the perceived need to include chest wall structures in the image field on the 90° lateral view compromised the detail of these images, because this required placement of a sponge between the breast and imaging cassette to permit use of gentle compression. (e) Lateral and (f) CC screen-film mammograms. This imaging technique was coupled with the use of a dedicated molybdenum-anode x-ray unit that provided uniform-thickness breast compression so that both thick and thin regions of the breast were properly exposed in the image. However, the combination of uniform-thickness breast compression and the use of the 90° lateral projection limited the amount of posterior tissues included in the image field.

View larger version (59K): [in this window] [in a new window] [Download PPT slide]   Figure 1f. Standard negative mammograms: 1965-1975. Standard examination included a 90° lateral and craniocaudal (CC) view of each breast. (a) Lateral and (b) CC direct-exposure film mammograms. There was only slight (if any) compression of the breast during exposure, which impaired depiction of tissues close to the chest wall because the x-ray beam could not effectively penetrate these thicker regions of the breast without grossly overexposing the thinner regions close to the nipple. (c) Lateral and (d) CC xeromammograms. The wide latitude of the xeroradiographic imaging process overcame the previously described limitation of direct-exposure film mammography. However, the perceived need to include chest wall structures in the image field on the 90° lateral view compromised the detail of these images, because this required placement of a sponge between the breast and imaging cassette to permit use of gentle compression. (e) Lateral and (f) CC screen-film mammograms. This imaging technique was coupled with the use of a dedicated molybdenum-anode x-ray unit that provided uniform-thickness breast compression so that both thick and thin regions of the breast were properly exposed in the image. However, the combination of uniform-thickness breast compression and the use of the 90° lateral projection limited the amount of posterior tissues included in the image field.

View larger version (81K): [in this window] [in a new window] [Download PPT slide]   Figure 2a. Standard negative mammograms: current. Standard examination now involves (a) MLO and (b) CC views of the breasts because the oblique view includes more posterior tissues in the image field than does the 90° lateral view. Also note that most breast structures are depicted more effectively than in the 1965-1975 period because of improvements in mammographic equipment, film, screens, film processing, grids, breast compression, and positioning.

View larger version (74K): [in this window] [in a new window] [Download PPT slide]   Figure 2b. Standard negative mammograms: current. Standard examination now involves (a) MLO and (b) CC views of the breasts because the oblique view includes more posterior tissues in the image field than does the 90° lateral view. Also note that most breast structures are depicted more effectively than in the 1965-1975 period because of improvements in mammographic equipment, film, screens, film processing, grids, breast compression, and positioning.

View larger version (70K): [in this window] [in a new window] [Download PPT slide]   Figure 3a. Standard negative mammograms: 1975 and current. Images of the same breast over a 25-year period. (a) A 90° lateral screen-film mammogram from 1975. (b) Current MLO screen-film mammogram. (c) CC screen-film mammogram from 1975. (d) Current CC screen-film mammogram. Note that the current images not only display much greater contrast and sharpness, but they also include in the image field several centimeters of additional breast tissue close to the chest wall. This latter comparison is facilitated by noting the amount of parenchyma included in the image field that is posterior to the (stable) island of benign fibroglandular tissue (arrow) in the upper medial portion of the breast (take into account that a and c are displayed relatively larger in size than b and d).

View larger version (104K): [in this window] [in a new window] [Download PPT slide]   Figure 3b. Standard negative mammograms: 1975 and current. Images of the same breast over a 25-year period. (a) A 90° lateral screen-film mammogram from 1975. (b) Current MLO screen-film mammogram. (c) CC screen-film mammogram from 1975. (d) Current CC screen-film mammogram. Note that the current images not only display much greater contrast and sharpness, but they also include in the image field several centimeters of additional breast tissue close to the chest wall. This latter comparison is facilitated by noting the amount of parenchyma included in the image field that is posterior to the (stable) island of benign fibroglandular tissue (arrow) in the upper medial portion of the breast (take into account that a and c are displayed relatively larger in size than b and d).

View larger version (61K): [in this window] [in a new window] [Download PPT slide]   Figure 3c. Standard negative mammograms: 1975 and current. Images of the same breast over a 25-year period. (a) A 90° lateral screen-film mammogram from 1975. (b) Current MLO screen-film mammogram. (c) CC screen-film mammogram from 1975. (d) Current CC screen-film mammogram. Note that the current images not only display much greater contrast and sharpness, but they also include in the image field several centimeters of additional breast tissue close to the chest wall. This latter comparison is facilitated by noting the amount of parenchyma included in the image field that is posterior to the (stable) island of benign fibroglandular tissue (arrow) in the upper medial portion of the breast (take into account that a and c are displayed relatively larger in size than b and d).

View larger version (97K): [in this window] [in a new window] [Download PPT slide]   Figure 3d. Standard negative mammograms: 1975 and current. Images of the same breast over a 25-year period. (a) A 90° lateral screen-film mammogram from 1975. (b) Current MLO screen-film mammogram. (c) CC screen-film mammogram from 1975. (d) Current CC screen-film mammogram. Note that the current images not only display much greater contrast and sharpness, but they also include in the image field several centimeters of additional breast tissue close to the chest wall. This latter comparison is facilitated by noting the amount of parenchyma included in the image field that is posterior to the (stable) island of benign fibroglandular tissue (arrow) in the upper medial portion of the breast (take into account that a and c are displayed relatively larger in size than b and d).

View larger version (212K): [in this window] [in a new window] [Download PPT slide]   Figure 4a. Circumscribed noncalcified mass: 1965-1975. Most such lesions were large and palpable, and therefore patients underwent excisional biopsy. (a) CC xeromammogram shows a 3-cm round circumscribed mass (arrow), which was excised and found to be a simple cyst. (b) A 90° lateral direct-exposure film mammogram in a different patient shows a 2.5-cm oval circumscribed mass (arrow), which was excised and found to be a fibroadenoma.

View larger version (161K): [in this window] [in a new window] [Download PPT slide]   Figure 4b. Circumscribed noncalcified mass: 1965-1975. Most such lesions were large and palpable, and therefore patients underwent excisional biopsy. (a) CC xeromammogram shows a 3-cm round circumscribed mass (arrow), which was excised and found to be a simple cyst. (b) A 90° lateral direct-exposure film mammogram in a different patient shows a 2.5-cm oval circumscribed mass (arrow), which was excised and found to be a fibroadenoma.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 5a. Circumscribed noncalcified mass: 1965-1975. (a) CC screen-film mammogram demonstrates a nonpalpable mass (arrow). During the course of needle localization prior to planned excision of this mass, clear fluid was seen to come from the hub of the localizing needle, which was suggestive of fortuitous puncture of a cyst. Additional fluid was then aspirated, air was injected in its place, and mammography was repeated. (b) CC screen-film pneumocystogram demonstrates an air-filled cavity (with no mural irregularity) instead of the mass. This established the diagnosis of a simple cyst, which obviated excisional biopsy.

View larger version (110K): [in this window] [in a new window] [Download PPT slide]   Figure 5b. Circumscribed noncalcified mass: 1965-1975. (a) CC screen-film mammogram demonstrates a nonpalpable mass (arrow). During the course of needle localization prior to planned excision of this mass, clear fluid was seen to come from the hub of the localizing needle, which was suggestive of fortuitous puncture of a cyst. Additional fluid was then aspirated, air was injected in its place, and mammography was repeated. (b) CC screen-film pneumocystogram demonstrates an air-filled cavity (with no mural irregularity) instead of the mass. This established the diagnosis of a simple cyst, which obviated excisional biopsy.

View larger version (127K): [in this window] [in a new window] [Download PPT slide]   Figure 6a. Circumscribed noncalcified mass: current. Most such lesions now are detected at mammographic screening, are nonpalpable even in retrospect, and are next evaluated with US to establish or exclude the diagnosis of a simple cyst. (a) CC screen-film mammogram demonstrates a 6 x 8-mm circumscribed mass (arrow). (b) Transverse sonogram shows the mass (arrow) to be anechoic and to exhibit smooth margins, a well-defined posterior border, and increased sound transmission. These sonographic features permit the reliable diagnosis of a simple cyst, a benign lesion that requires no further work-up.

View larger version (145K): [in this window] [in a new window] [Download PPT slide]   Figure 6b. Circumscribed noncalcified mass: current. Most such lesions now are detected at mammographic screening, are nonpalpable even in retrospect, and are next evaluated with US to establish or exclude the diagnosis of a simple cyst. (a) CC screen-film mammogram demonstrates a 6 x 8-mm circumscribed mass (arrow). (b) Transverse sonogram shows the mass (arrow) to be anechoic and to exhibit smooth margins, a well-defined posterior border, and increased sound transmission. These sonographic features permit the reliable diagnosis of a simple cyst, a benign lesion that requires no further work-up.

View larger version (152K): [in this window] [in a new window] [Download PPT slide]   Figure 7a. Circumscribed noncalcified mass: current. (a) CC screen-film spot-compression magnification mammogram demonstrates a 10 x 12-mm circumscribed mass (arrow), which was nonpalpable. (b) Transverse sonogram shows that the mass (cursors, arrow) is hypoechoic with homogeneous low-amplitude internal echoes, is wider than tall, and has smooth margins with a thin echogenic rim. This combination of mammographic and sonographic features indicates that the mass is solid, rather than cystic, and that it is probably benign (likelihood of malignancy, <2%). Most such lesions now are managed with periodic mammographic surveillance, rather than with any form of tissue diagnosis; the illustrated lesion was stable over a 3-year period of surveillance.

View larger version (154K): [in this window] [in a new window] [Download PPT slide]   Figure 7b. Circumscribed noncalcified mass: current. (a) CC screen-film spot-compression magnification mammogram demonstrates a 10 x 12-mm circumscribed mass (arrow), which was nonpalpable. (b) Transverse sonogram shows that the mass (cursors, arrow) is hypoechoic with homogeneous low-amplitude internal echoes, is wider than tall, and has smooth margins with a thin echogenic rim. This combination of mammographic and sonographic features indicates that the mass is solid, rather than cystic, and that it is probably benign (likelihood of malignancy, <2%). Most such lesions now are managed with periodic mammographic surveillance, rather than with any form of tissue diagnosis; the illustrated lesion was stable over a 3-year period of surveillance.

Grouped Microcalcifications
In the 1965–1975 period, the ease of depiction of grouped microcalcifications at mammography depended to a great extent on the image recording system that was used. Because of the low contrast and relatively poor compression (hence, frequent motion blur) that characterized film mammography at that time, tiny calcifications often were difficult to identify (Fig 8). However, the edge enhancement inherent in xeroradiography readily portrayed microcalcifications, even when only a small number of calcifications were present (Fig 9). Once detected, almost all clusters of microcalcifications were excised because at that time, there was no other reliable means to differentiate benign from malignant cases.

View larger version (104K): [in this window] [in a new window] [Download PPT slide]   Figure 8. Grouped microcalcifications: 1965-1975. CC direct-exposure film mammogram demonstrates grouped microcalcifications (curved arrow) within a large irregular mass (straight arrows). The calcifications are seen only faintly, primarily because of the low contrast inherent in direct-exposure film mammography. Findings from biopsy showed invasive ductal carcinoma with areas of ductal carcinoma in situ (DCIS).

View larger version (159K): [in this window] [in a new window] [Download PPT slide]   Figure 9. Grouped microcalcifications: 1965-1975. CC xeromammogram demonstrates a small cluster of microcalcifications (arrow), which was suggestive of malignancy. Findings from biopsy showed DCIS.

View larger version (181K): [in this window] [in a new window] [Download PPT slide]   Figure 10. Grouped microcalcifications: 1965-1975. A 90° lateral xeromammogram shows a large irregular mass (straight arrows) close to the chest wall; mass is associated with numerous microcalcifications. Also note a separate 6 x 9-mm cluster of microcalcifications (curved arrow) close to the nipple. Findings from biopsy showed invasive ductal carcinoma with multifocal DCIS.

View larger version (149K): [in this window] [in a new window] [Download PPT slide]   Figure 11a. Grouped microcalcifications: current. (a) CC screen-film mammogram shows a 3 x 4-mm cluster of microcalcifications (arrow). (b) CC screen-film spot-compression magnification mammogram displays the pleomorphic shapes of the calcific particles (straight arrow) more effectively but also demonstrates a second group of microcalcifications several centimeters distant (curved arrow). Findings from biopsy showed multifocal DCIS, which was subsequently treated with mastectomy rather than breast preservation.

View larger version (139K): [in this window] [in a new window] [Download PPT slide]   Figure 11b. Grouped microcalcifications: current. (a) CC screen-film mammogram shows a 3 x 4-mm cluster of microcalcifications (arrow). (b) CC screen-film spot-compression magnification mammogram displays the pleomorphic shapes of the calcific particles (straight arrow) more effectively but also demonstrates a second group of microcalcifications several centimeters distant (curved arrow). Findings from biopsy showed multifocal DCIS, which was subsequently treated with mastectomy rather than breast preservation.

View larger version (132K): [in this window] [in a new window] [Download PPT slide]   Figure 12a. Typical breast cancer—mass: 1965-1975. Most such lesions were large and palpable. Many were locally advanced tumors. (a) CC direct-exposure mammogram shows a 3-cm spiculated mass (straight arrow), associated with nipple retraction (curved arrow). Findings from biopsy showed invasive ductal carcinoma extending centrally to involve the nipple. (b) CC direct-exposure mammogram shows a poorly defined area of increased opacity (straight arrows), associated with generalized skin thickening (curved arrows). Findings from biopsy showed invasive ductal carcinoma with tumor extending to the skin and subdermal lymphatic vessels. (c) A 90° lateral xeromammogram shows a subtle 4-cm spiculated mass (straight arrows), associated with generalized skin thickening (curved arrows). Findings from biopsy showed invasive ductal carcinoma (inflammatory carcinoma).

View larger version (66K): [in this window] [in a new window] [Download PPT slide]   Figure 12b. Typical breast cancer—mass: 1965-1975. Most such lesions were large and palpable. Many were locally advanced tumors. (a) CC direct-exposure mammogram shows a 3-cm spiculated mass (straight arrow), associated with nipple retraction (curved arrow). Findings from biopsy showed invasive ductal carcinoma extending centrally to involve the nipple. (b) CC direct-exposure mammogram shows a poorly defined area of increased opacity (straight arrows), associated with generalized skin thickening (curved arrows). Findings from biopsy showed invasive ductal carcinoma with tumor extending to the skin and subdermal lymphatic vessels. (c) A 90° lateral xeromammogram shows a subtle 4-cm spiculated mass (straight arrows), associated with generalized skin thickening (curved arrows). Findings from biopsy showed invasive ductal carcinoma (inflammatory carcinoma).

View larger version (112K): [in this window] [in a new window] [Download PPT slide]   Figure 12c. Typical breast cancer—mass: 1965-1975. Most such lesions were large and palpable. Many were locally advanced tumors. (a) CC direct-exposure mammogram shows a 3-cm spiculated mass (straight arrow), associated with nipple retraction (curved arrow). Findings from biopsy showed invasive ductal carcinoma extending centrally to involve the nipple. (b) CC direct-exposure mammogram shows a poorly defined area of increased opacity (straight arrows), associated with generalized skin thickening (curved arrows). Findings from biopsy showed invasive ductal carcinoma with tumor extending to the skin and subdermal lymphatic vessels. (c) A 90° lateral xeromammogram shows a subtle 4-cm spiculated mass (straight arrows), associated with generalized skin thickening (curved arrows). Findings from biopsy showed invasive ductal carcinoma (inflammatory carcinoma).

View larger version (99K): [in this window] [in a new window] [Download PPT slide]   Figure 13a. Typical breast cancer—mass: 1965-1975. (a) CC direct-exposure film mammogram shows a 7-mm spiculated mass (arrow), which was subtle in manifestation. Findings from biopsy showed invasive ductal carcinoma. (b) CC direct-exposure film mammogram shows a 1-cm mass (arrow) with indistinct margins, which was subtle in manifestation. Findings from biopsy showed invasive ductal carcinoma.

View larger version (84K): [in this window] [in a new window] [Download PPT slide]   Figure 13b. Typical breast cancer—mass: 1965-1975. (a) CC direct-exposure film mammogram shows a 7-mm spiculated mass (arrow), which was subtle in manifestation. Findings from biopsy showed invasive ductal carcinoma. (b) CC direct-exposure film mammogram shows a 1-cm mass (arrow) with indistinct margins, which was subtle in manifestation. Findings from biopsy showed invasive ductal carcinoma.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 14a. Typical breast cancer—mass: current. The superior image quality of current mammography facilitates the detection of small nonpalpable breast cancers (compare with Fig 13). (a) MLO screen-film mammogram and (b) 90° lateral screen-film spot-compression magnification mammogram demonstrate a 6 x 9-mm spiculated mass (arrow). Both the mass and its spiculations are depicted more clearly in b. Findings from biopsy showed invasive ductal carcinoma. (c) MLO and (d) CC screen-film mammograms show a 7 x 9-mm mass (arrow) with indistinct margins in the lower outer quadrant, close to the chest wall. Findings from biopsy showed invasive ductal carcinoma.

View larger version (128K): [in this window] [in a new window] [Download PPT slide]   Figure 14b. Typical breast cancer—mass: current. The superior image quality of current mammography facilitates the detection of small nonpalpable breast cancers (compare with Fig 13). (a) MLO screen-film mammogram and (b) 90° lateral screen-film spot-compression magnification mammogram demonstrate a 6 x 9-mm spiculated mass (arrow). Both the mass and its spiculations are depicted more clearly in b. Findings from biopsy showed invasive ductal carcinoma. (c) MLO and (d) CC screen-film mammograms show a 7 x 9-mm mass (arrow) with indistinct margins in the lower outer quadrant, close to the chest wall. Findings from biopsy showed invasive ductal carcinoma.

View larger version (129K): [in this window] [in a new window] [Download PPT slide]   Figure 14c. Typical breast cancer—mass: current. The superior image quality of current mammography facilitates the detection of small nonpalpable breast cancers (compare with Fig 13). (a) MLO screen-film mammogram and (b) 90° lateral screen-film spot-compression magnification mammogram demonstrate a 6 x 9-mm spiculated mass (arrow). Both the mass and its spiculations are depicted more clearly in b. Findings from biopsy showed invasive ductal carcinoma. (c) MLO and (d) CC screen-film mammograms show a 7 x 9-mm mass (arrow) with indistinct margins in the lower outer quadrant, close to the chest wall. Findings from biopsy showed invasive ductal carcinoma.

View larger version (120K): [in this window] [in a new window] [Download PPT slide]   Figure 14d. Typical breast cancer—mass: current. The superior image quality of current mammography facilitates the detection of small nonpalpable breast cancers (compare with Fig 13). (a) MLO screen-film mammogram and (b) 90° lateral screen-film spot-compression magnification mammogram demonstrate a 6 x 9-mm spiculated mass (arrow). Both the mass and its spiculations are depicted more clearly in b. Findings from biopsy showed invasive ductal carcinoma. (c) MLO and (d) CC screen-film mammograms show a 7 x 9-mm mass (arrow) with indistinct margins in the lower outer quadrant, close to the chest wall. Findings from biopsy showed invasive ductal carcinoma.

View larger version (185K): [in this window] [in a new window] [Download PPT slide]   Figure 15. Typical breast cancer—calcifications: 1965-1975. Those cancers detected at mammography as grouped microcalcifications often were large lesions. CC xeromammogram shows extensive grouped microcalcifications (arrows) occupying a large area in the middle and posterior thirds of the breast. Findings from biopsy showed a 2.5-cm invasive ductal carcinoma (not depicted at mammography), with extensive associated DCIS.

View larger version (141K): [in this window] [in a new window] [Download PPT slide]   Figure 16a. Typical breast cancer—calcifications: current. (a) CC screen-film mammogram and (b) CC screen-film spot-compression magnification mammogram show a 5 x 9-mm area of subtle microcalcifications (arrows), adjacent to one coarse calcification. Pleomorphic microcalcifications are seen more clearly in b. Findings from biopsy showed DCIS. (c) CC screen-film mammogram shows subtle, possibly linearly distributed microcalcifications (arrow), which prompted further work-up with (d) CC screen-film spot-compression magnification mammogram, which demonstrates that the microcalcifications (arrows) are much more extensive, include some linear-shaped calcific particles, and occupy a segmental distribution. Findings from biopsy showed multifocal DCIS.

View larger version (142K): [in this window] [in a new window] [Download PPT slide]   Figure 16b. Typical breast cancer—calcifications: current. (a) CC screen-film mammogram and (b) CC screen-film spot-compression magnification mammogram show a 5 x 9-mm area of subtle microcalcifications (arrows), adjacent to one coarse calcification. Pleomorphic microcalcifications are seen more clearly in b. Findings from biopsy showed DCIS. (c) CC screen-film mammogram shows subtle, possibly linearly distributed microcalcifications (arrow), which prompted further work-up with (d) CC screen-film spot-compression magnification mammogram, which demonstrates that the microcalcifications (arrows) are much more extensive, include some linear-shaped calcific particles, and occupy a segmental distribution. Findings from biopsy showed multifocal DCIS.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 16c. Typical breast cancer—calcifications: current. (a) CC screen-film mammogram and (b) CC screen-film spot-compression magnification mammogram show a 5 x 9-mm area of subtle microcalcifications (arrows), adjacent to one coarse calcification. Pleomorphic microcalcifications are seen more clearly in b. Findings from biopsy showed DCIS. (c) CC screen-film mammogram shows subtle, possibly linearly distributed microcalcifications (arrow), which prompted further work-up with (d) CC screen-film spot-compression magnification mammogram, which demonstrates that the microcalcifications (arrows) are much more extensive, include some linear-shaped calcific particles, and occupy a segmental distribution. Findings from biopsy showed multifocal DCIS.

View larger version (132K): [in this window] [in a new window] [Download PPT slide]   Figure 16d. Typical breast cancer—calcifications: current. (a) CC screen-film mammogram and (b) CC screen-film spot-compression magnification mammogram show a 5 x 9-mm area of subtle microcalcifications (arrows), adjacent to one coarse calcification. Pleomorphic microcalcifications are seen more clearly in b. Findings from biopsy showed DCIS. (c) CC screen-film mammogram shows subtle, possibly linearly distributed microcalcifications (arrow), which prompted further work-up with (d) CC screen-film spot-compression magnification mammogram, which demonstrates that the microcalcifications (arrows) are much more extensive, include some linear-shaped calcific particles, and occupy a segmental distribution. Findings from biopsy showed multifocal DCIS.

View larger version (37K): [in this window] [in a new window] [Download PPT slide]   Figure 17. Breast implants: 1965-1975. A 90° lateral direct-exposure film mammogram shows a breast augmented with a prepectoral silicone-filled implant. Note that little breast parenchyma is depicted and that only the anterior portion of the implant (arrows) is included in the image field.

View larger version (122K): [in this window] [in a new window] [Download PPT slide]   Figure 18. Breast implants: 1965-1975. A 90° lateral xeromammogram demonstrates a prepectoral silicone-filled implant. The wide latitude of xeroradiography permits effective simultaneous depiction of all imaged structures, from chest wall to implant to native fibroglandular tissue to breast fat. There is extracapsular rupture of the implant, which is shown by the demonstration of numerous silicone nodules (arrows) superimposed over the implant, indicating the presence of free silicone within the breast parenchyma.

View larger version (60K): [in this window] [in a new window] [Download PPT slide]   Figure 19a. Breast implants: current. MLO screen-film mammograms of a breast augmented with a prepectoral silicone-filled implant, with (a) implant included in the image field and (b) implant displaced posteriorly, which more effectively portrays the native fibroglandular tissue. Just anterior to the implant, there is an area of architectural distortion (arrow), which is seen only in b. This finding prompted further imaging with (c) implant-displaced spot-compression magnification mammogram, obtained with the x-ray beam aligned tangential to the area of architectural distortion, showing a 1.5-cm spiculated mass containing microcalcifications (arrow). Findings from biopsy showed invasive ductal carcinoma with a minor component of DCIS.

View larger version (85K): [in this window] [in a new window] [Download PPT slide]   Figure 19b. Breast implants: current. MLO screen-film mammograms of a breast augmented with a prepectoral silicone-filled implant, with (a) implant included in the image field and (b) implant displaced posteriorly, which more effectively portrays the native fibroglandular tissue. Just anterior to the implant, there is an area of architectural distortion (arrow), which is seen only in b. This finding prompted further imaging with (c) implant-displaced spot-compression magnification mammogram, obtained with the x-ray beam aligned tangential to the area of architectural distortion, showing a 1.5-cm spiculated mass containing microcalcifications (arrow). Findings from biopsy showed invasive ductal carcinoma with a minor component of DCIS.

View larger version (94K): [in this window] [in a new window] [Download PPT slide]   Figure 19c. Breast implants: current. MLO screen-film mammograms of a breast augmented with a prepectoral silicone-filled implant, with (a) implant included in the image field and (b) implant displaced posteriorly, which more effectively portrays the native fibroglandular tissue. Just anterior to the implant, there is an area of architectural distortion (arrow), which is seen only in b. This finding prompted further imaging with (c) implant-displaced spot-compression magnification mammogram, obtained with the x-ray beam aligned tangential to the area of architectural distortion, showing a 1.5-cm spiculated mass containing microcalcifications (arrow). Findings from biopsy showed invasive ductal carcinoma with a minor component of DCIS.

View larger version (82K): [in this window] [in a new window] [Download PPT slide]   Figure 20a. Breast implants: current. MR imaging, because of its ability to produce cross-sectional images and to depict silicone at substantially different signal intensity than all other structures, depicts the integrity of breast implants with a high degree of accuracy. (a) Sagittal T2-weighted fast spin-echo MR image with water suppression (4,000/200 [repetition time msec/echo time msec]) shows a breast augmented with a prepectoral silicone-filled implant and demonstrates free silicone (arrow) immediately posterior to the implant shell. This finding represented the only imaging evidence of extracapsular implant rupture in this case,