An investigation into the use of sensitivity-encoded techniques to increase temporal resolution in dynamic contrast-enhanced breast imaging

Gadolinium-enhanced dynamic magnetic resonance (MR) imaging is playing an increasingly important diagnostic role in patients with breast cancer. Because of the multi-focal nature of the disease, it is mandatory to cover all of both breasts, not only in the initial scan, but also at subsequent follow-up. This requires volume acquisitions with a temporal resolution limited to 60-80 seconds, which is insufficient to clearly discriminate malignant from benign rates of contrast uptake. In this work, we performed sensitivity-encoded imaging using a commercially available four-channel breast coil (MRI Devices Corporation) on a commercial 0.5-T scanner with moderate gradient performance to give increased temporal resolution in these dynamic contrast-enhanced scans. A two-fold increase in temporal resolution was readily achievable with this coil. Image reconstruction was robust and image quality was assessed qualitatively to be good. We also investigated higher speed-up factors using two directions of sensitivity-encoded reduction and discussed some of the potential artifacts associated with such imaging.

Can tamoxifen cause a significant mammographic density change in breast parenchyma?

To evaluate tamoxifen-induced glandular tissue density changes in women who are on an adjuvant tamoxifen therapy. We examined serial mammograms of 27 women (average age 67) who had surgery for unilateral breast carcinoma and were on tamoxifen for 5 years. Mammograms obtained at the beginning of treatment, within 2 or 3 years, at the end of 5 years and 1 year after cessation of tamoxifen treatment, were evaluated by two radiologists experienced in reading mammograms. Four 1-cm-diameter circular areas of the glandular tissue and retroglandular fat were sampled by a densitometer and a relative glandular density (glandular tissue/fat density) was used for comparison between serial mammograms. Most cases (79%) did not show tamoxifen-induced change in glandular density. Three patients (13%) showed an early and two (8%) a delayed mild reduction in glandular density as compared to baseline mammograms. No patient was found to have increased glandular density following the cessation of tamoxifen therapy (in subjective evaluation). Densitometer readings showed a mild reduction in glandular densities in 16 cases (60%) during treatment and a minimal increase in 13 cases (48%) following cessation of treatment. There was a slight decrease in breast density during treatment [relative density of 0.012+/-0.006 (standard error) per interval, P value:.06] and the difference between years 5 and 6 was nearly zero [relative density of 0.00042+/-0.01 (standard error), P value:.97]. Long-term use of tamoxifen may cause a mild reduction in breast glandular density, although this, in part, may be attributed to the age-related mammographic density change. Following cessation of tamoxifen, no significant increase in glandular density was observed. Therefore, any increase in mammographic density during or after tamoxifen treatment should be viewed with suspicion and further evaluated.

Mammary gland architecture as a determining factor in the susceptibility of the human breast to cancer

The developmental pattern of the breast can be assessed by determining the composition of the breast in specific lobular structures, which are designated as lobules type 1 (Lob 1), lobules type 2 (Lob 2), and lobules type 3 (Lob 3), with Lob 1 being the less developed and Lob 3 being the most differentiated or with the highest number of ductules per lobular unit. In the present work, the patient population consisted of three groups of women who underwent surgical procedures: The first group included women who underwent reduction mammoplasty (RM) for cosmetic reasons. The second group included women who underwent prophylactic subcutaneous mastectomy after genetic counseling for either carrying the BRCA-1 gene or belonging to a pedigree with familial breast cancer (FAM), and the third group included women who underwent modified radical mastectomy (MRM) for the diagnosis of invasive carcinoma. The RM group consisted of 33 women, of whom 9 were nulliparous and 24 were parous. The FAM group consisted of 17 women, of whom 8 were nulliparous and 9 were parous. The MRM group consisted of 43 women, of whom 7 were nulliparous and 36 were parous. The analysis of the lobular composition of all of the samples from the RM group, which is considered the control group, revealed that Lob 1 represented 22%, Lob 2 represented 37%, and Lob 3 represented 38%, whereas the tissue examined from the FAM and MRM groups contained a preponderance of Lob 1 at 48% and 74%, respectively, over Lob 3, which was 10% and 3%, respectively. When the results of the analysis of breast tissue were separated according to the pregnancy history of the donor, it was found that in the control group or RM, there was a significant difference in lobular composition. Nulliparous women of the RM group showed a preponderance of Lob 1 (46%) over parous women, which contained only 17%, whereas the percentage of Lob 3 in the nulliparous group was significantly lower (7%) than the parous group (48%). In the breast tissues obtained from FAM and MRM, no significant differences in lobular composition were observed, as all of the samples contained a higher concentration of Lob 1, independent of the pregnancy history. The breast tissue of FAM and MRM of parous women had a developmental pattern that was similar to that of nulliparous women of the same group and that was less developed than the breast of parous women of the control group. An important difference between the Lob 1 of the FAM group versus the control (RM) and the MRM group was that most of these lobules had thin ductules with an increase in hyalinization of the intralobular stroma manifested in the whole-mount preparation as an alteration in the branching pattern. The data suggest that the breast tissue of women with invasive cancer, as well as those from a background of familial breast cancer, have an architectural pattern different from the control or normal tissues and that the BRCA-1 or related genes may have a functional role in the branching pattern of the breast during lobular development, mainly in the epithelial stroma interaction.

Differentiation of breast calcifications

Breast calcifications display a variety of characteristics, depending on the physiological process leading to their development. Because certain types of calcifications can be indicative of breast cancer, it is important that mammographers recognize which calcifications signify a benign or malignant process. In addition to discussing the causes of breast calcifications and describing ways to optimize their mammographic depiction, this article explains the differences in the mammographic appearances of various types of breast calcifications.

Computer-assisted complete three-dimensional reconstruction of the mammary ductal/lobular systems: implications of ductal anastomoses for breast-conserving surgery

BACKGROUND

The intraductal spread of breast carcinoma can occur along the mammary ductal/lobular systems (MDLS) with no invasion of tissues. Because ductal anastomoses in the MDLS are considered to be a possible risk factor for extensive intraductal spread of breast carcinoma, the architecture of the MDLS has important therapeutic implications for patients treated with breast-conserving surgery.

METHODS

An entire breast resected by subcutaneous mastectomy from a 69-year-old woman with ductal carcinoma in situ (DCIS) was examined in submacroscopic sections by stereomicroscopic and histologic techniques. Serial 2-mm sections underwent computer-assisted complete three-dimensional reconstruction of all MDLS.

RESULTS

The entire breast that was studied contained 16 MDLS that were arranged radially, with the nipple at the center. Of these 16 MDLS, 4 (25.0%) had ductal anastomoses whereas the remaining 12 MDLS had no ductal anastomoses and completely independent regional anatomy. Ductal anastomoses were observed at 11 sites in the 4 MDLS. The 2 of 11 ductal anastomoses that connected different MDLS (18.2%) were situated > 4 cm from the nipple. The remaining nine ductal anastomoses connected ducts within the same MDLS; their location varied from near the nipple to the peripheral region. In the specimen examined, DCIS extended only within a single MDLS and did not spread between different MDLS via ductal anastomoses.

CONCLUSIONS

To the authors' knowledge, the current study is the first time the complete architecture of all MDLS in an entire breast has been studied three-dimensionally. The risk of promoting the intraductal spread of disease during surgery may be greater when intraductal lesions extend more peripherally than centrally. The features of ductal anastomoses may provide a significant anatomic clue regarding negative surgical margins in breast-conserving surgery.

Comparison of Immunoperoxidase Staining of 3 Different Types of CD5 Antibodies in a Spectrum of Breast Lesions

Context.—We recently described a patient with chronic lymphocytic leukemia who presented with a breast carcinoma that stained positive for CD5 using a commercially available antibody (CD5-4C7, Novocastra, Newcastle upon Tyne, UK).

Objectives.—To study the distribution of CD5 immunoreactivity in tissue sections of a variety of benign and malignant breast lesions using the antibody CD5-4C7 and to compare the results with those obtained with 2 other commercially available CD5 antibodies (CD5/54/F6, Dako, Ely, Cambridgeshire, UK, and CD5/54/B4, Novocastra).

Design.—Paraffin sections of 102 breast biopsy specimens with various diagnoses were examined using the avidin-biotin immunoperoxidase complex technique.

Setting.—The histopathology department of a tertiary referral teaching hospital.

Results.—The staining results obtained with CD5-4C7 were different from those obtained with the other 2 antibodies. With 4C7, the normal and benign biopsy specimens showed varying numbers of positive epithelial cells and lymphocytes. Heterogeneous positive staining was also present in 47 (78%) of 60 invasive female breast carcinomas and in all 3 male breast carcinomas examined. A statistically significant correlation was found between CD5 positivity and tumor grade, with grade 3 tumors being less likely to be CD5 positive than grades 1 and 2 (P = .0035). No correlation was found between CD5 positivity and patient's age, tumor histologic type, axillary lymph node status, or progesterone receptors. On the other hand, the CD5/54/F6 and CD5/54/B4 antibodies only stained lymphocytes and occasional normal breast ducts, mostly those showing apocrine metaplasia. All other normal benign and malignant epithelial cells were negative.

Conclusions.—Positive staining for CD5 using the antibody 4C7 is seen in normal and benign breast tissue and 78% of invasive breast carcinomas. The positivity is more common in low-grade tumors. No significant staining was seen with the 2 other CD5 clones used in this study. The significance of the positive staining obtained with CD5-4C7 is not obvious, but this clone may be more sensitive than the others, or it may be recognizing an epitope shared by another antigen.

The lateral thoracodorsal flap in breast reconstruction: a long-term follow up study

Fifty-four patients were studied a mean of five years after their breasts had been reconstructed between 1984 and 1990 using the lateral thoracodorsal (LTD) flap in combination with either a thin shell, non-low-bleed (n = 35) or a thick shell, low bleed (n = 19) silicone gel implant. The rate of capsular contracture (Baker III-IV) was 11% in the first group and 10% in the second according to a modified Baker classification. Open capsulotomy was common in both groups of patients (15/35 in the first group and 13/19 in the second). Investigation by applanation tonometry of the capsular contracture agreed with the modified Baker classification. The cosmetic results were evaluated clinically and from photographs. Best scores were recorded for scars and ptosis in both evaluations. There were no significant differences between the general cosmetic results in the two groups. The patients graded their estimations of the final outcome of their breast reconstruction on a 10-point visual analogue scale (VAS); the mean for the first group was 8.7 and for the second 9.2. None of the patients regretted her operation and they would all recommend the procedure to another patient.

Computerized image analysis: estimation of breast density on mammograms

An automated image analysis tool is being developed for the estimation of mammographic breast density. This tool may be useful for risk estimation or for monitoring breast density change in prevention or intervention programs. In this preliminary study, a data set of 4-view mammograms from 65 patients was used to evaluate our approach. Breast density analysis was performed on the digitized mammograms in three stages. First, the breast region was segmented from the surrounding background by an automated breast boundary-tracking algorithm. Second, an adaptive dynamic range compression technique was applied to the breast image to reduce the range of the gray level distribution in the low frequency background and to enhance the differences in the characteristic features of the gray level histogram for breasts of different densities. Third, rule-based classification was used to classify the breast images into four classes according to the characteristic features of their gray level histogram. For each image, a gray level threshold was automatically determined to segment the dense tissue from the breast region. The area of segmented dense tissue as a percentage of the breast area was then estimated. To evaluate the performance of the algorithm, the computer segmentation results were compared to manual segmentation with interactive thresholding by five radiologists. A "true" percent dense area for each mammogram was obtained by averaging the manually segmented areas of the radiologists. We found that the histograms of 6% (8 CC and 8 MLO views) of the breast regions were misclassified by the computer, resulting in poor segmentation of the dense region. For the images with correct classification, the correlation between the computer-estimated percent dense area and the "truth" was 0.94 and 0.91, respectively, for CC and MLO views, with a mean bias of less than 2%. The mean biases of the five radiologists' visual estimates for the same images ranged from 0.1% to 11%. The results demonstrate the feasibility of estimating mammographic breast density using computer vision techniques and its potential to improve the accuracy and reproducibility of breast density estimation in comparison with the subjective visual assessment by radiologists.

False positive ECG reports of anterior myocardial infarction in women

The prevalence of electrocardiographic poor R-wave progression was estimated by reviewing all electrocardiograms recorded in Glasgow Royal Infirmary over a 2-week period. It was found to be higher in women (19% vs. 11%) than in men. To investigate one possible reason, the effect of chest electrode positioning in women was thereafter examined. Eighty four women were recruited to a study in which chest electrodes were placed strictly in adherence with recommendations of using the 4th and 5th intercostal spaces as references and also using the more widely adopted technique of placing electrodes V3 to V6 under the left breast. R wave amplitudes were compared in V3 to V6 from both sets of recordings. It was found that measurements recorded on the breast by electrode V3 have a significantly smaller R wave magnitude compared to corresponding measurements below the breast, the mean difference being 34 (95% confidence interval [CI] of 7 to 60) microvolts. For V5 and V6, the reverse is true with measurements taken on the breast being larger, on average, than those taken below the breast by 119 (95% CI of 87 to 152) and 134 (95% CI of 108 to 160) microvolts respectively. For V4, there was no significant difference. Seventeen women with poor R wave progression suggestive of old anterior myocardial infarction had clinical data examined from which it was determined that 11 had a history suggestive of myocardial infarction, ie, the positive predictive value was 65% (95% CI of 42% to 87%). It was concluded that positioning of electrodes beneath rather than on top of the breast was not responsible for the increased prevalence of poor R wave progression in women and that the criterion of isolated poor R wave progression was too nonspecific to be of clinical value.

A TiO(2) dielectric filled toroidal radio frequency cavity resonator for high-field NMR

R(F) performance in high-field MRI applications is improved by filling the resonator with material of relative dielectric constant approximating that of human soft tissue. We demonstrate this by filling a toroidal cavity resonator operating in TEM(00) (cyclotron) mode with titanium dioxide (TiO(2)) in powdered rutile form, and acquiring phantom, human lower leg and human breast images of good quality at 4.1 T. Images made with this resonator had unusually high SNR, while the level of R(f) power required to produce a 90 degrees flip angle pulse was about a quartes as high for the filled resonator as for the same resonator before filling. Phantom images obtained with the filled resonator had an SNR of nearly 300 at a resolution of 256 x 256 voxels, nearly three times that of images of the same phantom obtained using a standard volume R(f) coil in frequent use at this laboratory. Breast images made at 256 x 256 voxels resolution had an SNR of 174, also unusually high for a volume coil. High-resolution (512 x 512 voxels) were also obtained, with SNR = 60. Preliminary phantom and in vivo human images are presented in this article. Acquiring the phantom and leg images required significantly less R(f) power than did comparable imaging using a conventional coil. In addition, the field lines were focused as they penetrated into the sample, and this resulted in a more homogeneous B(1)-field. We believe that these improvements occurred because the dielectric presence minimizes the large dielectric mismatch between air and sample.

A simulation of the effects of set-up error and changes in breast volume on conventional and intensity-modulated treatments in breast radiotherapy

The effect of interfractional patient movement on dosimetry has been investigated for breast radiotherapy. Errors in patient set-up and changes in breast volume were simulated individually to determine how each contributes to the total dosimetric error. Two treatment techniques were investigated: a conventional treatment and an intensity-modulated treatment delivered using compensators. Six patients were investigated and anterior-posterior (AP) and superior-inferior (SI) displacements were simulated by displacing the isocentre in both directions by 2, 5 and 10 mm. A model of the breast was developed from the six patients to simulate changes in breast volume. In this model, the breast was described as a set of semi-ellipses. The volume of the breast was changed by varying the magnitude of the semi-major and semi-minor axes. Anisotropic changes in breast volume were also investigated. The dosimetric error was evaluated for each dose plan by calculating the volume outside the 95-105% dose range resulting from the simulations. A number of parameters describing the size and shape of the breast were also investigated to determine whether a susceptibility of outline sets to interfractional patient movement could be predicted. A parameter describing the increase in the breast volume outside the 95-105% dose range was calculated for AP a

Stereotactic breast biopsy

This overview of stereotactic breast biopsy describes the procedure's advantages over surgical biopsy as well as contraindications for its use. Patient and procedural considerations are discussed, along with the equipment used, technologist qualifications and imaging and positioning techniques. The article concludes with a discussion of quality assurance requirements.

Breast ultrasound

Ultrasound is second in importance only to mammography in the evaluation of breast abnormalities. The ability of US to diagnose benign simple cysts accurately has spared innumerable women from needless biopsies and aspirations. When a suspicious solid abnormality is detected by ultrasound, it readily provides convenient, inexpensive, accurate imaging guidance for interventional procedures. Future studies of US as a screening tool must weigh potential benefits against the potential risks because of increased biopsies performed for false-positive results.

Three-dimensional subzone-based reconstruction algorithm for MR elastography

Accurate characterization of harmonic tissue motion for realistic tissue geometries and property distributions requires knowledge of the full three-dimensional displacement field because of the asymmetric nature of both the boundaries of the tissue domain and the location of internal mechanical heterogeneities. The implications of this for magnetic resonance elastography (MRE) are twofold. First, for MRE methods which require the measurement of a harmonic displacement field within the tissue region of interest, the presence of 3D motion effects reduces or eliminates the possibility that simpler, lower-dimensional motion field images will capture the true dynamics of the entire stimulated tissue. Second, MRE techniques that exploit model-based elastic property reconstruction methods will not be able to accurately match the observed displacements unless they are capable of accounting for 3D motion effects. These two factors are of key importance for MRE techniques based on linear elasticity models to reconstruct mechanical tissue property distributions in biological samples. This article demonstrates that 3D motion effects are present even in regular, symmetric phantom geometries and presents the development of a 3D reconstruction algorithm capable of discerning elastic property distributions in the presence of such effects. The algorithm allows for the accurate determination of tissue mechanical properties at resolutions equal to that of the MR displacement image in complex, asymmetric biological tissue geometries. Simulation studies in a realistic 3D breast geometry indicate that the process can accurately detect 1-cm diameter hard inclusions with 2.5x elasticity contrast to the surrounding tissue.

The effect of age and density of the breast on the sensitivity of breast cancer diagnostic by mammography and ultasonography

PURPOSE

We studied which, age of the patient or density of the breast accounts for the sensitivity of mammography and ultrasonography (US). Furthermore we studied whether the overall impression on the density of the breast or the density in tumour area accounts for the sensitivity of mammography and ultrasonography.

MATERIALS AND METHODS

The material consisted of 572 consecutive histologically and 5 cytologically verified breast cancer cases. Mammography and US examinations were performed immediately before breast cancer operations and information on the findings were received from the original patient files and classified as malignant or benign. The density of breast parenchyma to fatty, mixed or dense in total breast and separately in tumour area was defined by a radiologist group from the original mammograms by comparing to model mammograms. The sensitivity (Se) of mammography and US was compared in 3 age groups (26-49, 50-59 and 60-92) and in the different density classes.

RESULTS

Sensitivity of mammography increased by age (density-adjusted OR = 0.2, 95%, CI 0.1-0.5) in age group 26-49 compared to age group 60-92) and with fattiness of the breast (age-adjusted OR= 0.4, 95%, CI 0.1-1.0 for dense breast parenchyma in tumour area compared to fatty breast). Sensitivity of US was inversely related to age (density-adjusted OR = 2.3, 95%, CI 1.0-5.2 in age group 26-49 compared to age group 60-92) and directly related with fattiness of breast (age-adjusted OR = 0.5, 95%, CI 0.2-0.9 by dense breast parenchyma in tumour area compared to fatty breast). Density in the tumour area compared to total breast density was related only mariginally better sensitivity both of mammography (0.4 vs. 0.6) and of US (0.5 vs. 0.6).

CONCLUSION

Sensitivity of both mammography and sensitivity of US are independently related both to the age of the patient and to the density of the breast. The effect of age is inverse and that of density parallel between mammography and US on sensitivity. The effect of overall breast density was close to the effect of density at the site of the tumour on the sensitivity of both mammography and US.

Dual Plane Breast Augmentation: Optimizing Implant-Soft-Tissue Relationships in a Wide Range of Breast Types

In breast augmentation, surgeons usually choose a pocket location for the implant behind breast parenchyma (retromammary), partially behind the pectoralis major muscle (partial retropectoral), or totally behind pectoralis major and serratus (total submuscular). Each of these implant pocket locations has specific indications, but each also has a unique set of tradeoffs. When applied to a wide range of breast types, each pocket location has limitations. Glandular ptotic and constricted lower pole breasts offer unique challenges that often are not solved without tradeoffs when using a strictly retromammary, partial retropectoral, or total submuscular pocket. This article describes specific indications and techniques for a dual plane approach to breast augmentation in several different breast types, introducing techniques that combine retromammary and partial retropectoral pocket locations in a single patient to optimize the benefits of each pocket location while limiting the tradeoffs and risks of a single pocket location. A total of 468 patients had dual plane augmentation between January of 1992 and March of 1998 using the specific techniques of dual plane augmentation described in this article. All patients were treated as outpatients and received general anesthesia. Indications, operative techniques, results, and complications for this series of patients are presented. Dual plane augmentation mammaplasty adjusts implant and tissue relationships to ensure adequate soft-tissue coverage while optimizing implant-soft-tissue dynamics to offer increased benefits and fewer tradeoffs compared with a single pocket location in a wide range of breast types.

Biomechanical 3-D finite element modeling of the human breast using MRI data

Breast tissue deformation modeling has recently gained considerable interest in various medical applications. A biomechanical model of the breast is presented using a finite element (FE) formulation. Emphasis is given to the modeling of breast tissue deformation which takes place in breast imaging procedures. The first step in implementing the FE modeling (FEM) procedure is mesh generation. For objects with irregular and complex geometries such as the breast, this step is one of the most difficult and tedious tasks. For FE mesh generation, two automated methods are presented which process MRI breast images to create a patient-specific mesh. The main components of the breast are adipose, fibroglandular and skin tissues. For modeling the adipose and fibroglandular tissues, we used eight noded hexahedral elements with hyperelastic properties, while for the skin, we chose four noded hyperelastic membrane elements. For model validation, an MR image of an agarose phantom was acquired and corresponding FE meshes were created. Based on assigned elasticity parameters, a numerical experiment was performed using the FE meshes, and good results were obtained. The model was also applied to a breast image registration problem of a volunteer's breast. Although qualitatively reasonable, further work is required to validate the results quantitatively.

Is a dense mammographic parenchymal pattern a contraindication to hormonal replacement therapy?

The aim of the study was to find out whether the effect of hormonal replacement therapy (HRT) is modified by the mammographic parenchymal patterns on the risk of breast cancer. Subjects were 4163 Finnish women aged 40-47 years at entry who were invited to breast cancer screening every second year from 1982 to 1990. Mammographic parenchymal patterns (Wolfe's classification) were recorded at each screening round. The information, on use of HRT, was recorded from 1984. The follow-up ended in 1993 and up until that time 68 new breast cancers were diagnosed. A Poisson regression model was used in the analysis of the data. Use of HRT was not related to the risk of breast cancer (RR = 0.7, 95% CI 0.4-1.4), whereas mammographic parenchymal pattern was statistically significantly associated with risk of breast cancer. The age-adjusted relative risk of breast cancer among women with P2 versus N1 pattern was 2.5 (95% CI 1.3-4.8) and with DY versus N1 pattern 4.9 (951% CI 1.6-15.1). Women using HRT and with DY pattern were at substantially increased risk of breast cancer (RR = 11.6, 95% CI 2.5-53.6) compared with women not using HRT and with N1 pattern. There was an increased risk of breast cancer among women with DY mammographic parenchymal pattern who used HRT, which was consistent with a synergistic joint effect.

Developmental, cellular, and molecular basis of human breast cancer

Breast cancer, which is the most common neoplastic disease in females and accounts for up to one third of all new cases of women's cancer in North America, continues to rise in incidence. In addition, the mortality caused by this disease has remained almost unchanged for the past 5 decades, becoming only second to lung cancer as a cause of cancer-related death. The failure in eradicating this disease is largely due to the lack of identification of a specific etiologic agent, the precise time of initiation, and the molecular mechanisms responsible for cancer initiation and progression. Despite the numerous uncertainties surrounding the origin of cancer, there is substantial evidence that breast cancer risk relates to endocrinologic and reproductive factors. The development of breast cancer strongly depends on the ovary and on endocrine conditions modulated by ovarian function, such as early menarche, late menopause, and parity. However, the specific hormone or hormone combinations responsible for cancer initiation have not been identified, and their role as protective or risk factors is still incompletely understood. A highly significant female hormone is estrogen, which is involved in the development of a variety of cancers, but it is still unclear whether estrogens are carcinogenic to the human breast. An understanding of whether estrogens cause mutations, and, if so, whether they act through hormonal effects activated by receptor binding, cytochrome P450-mediated metabolic activation, or compromise the DNA repair system, is essential for determining whether this steroid hormone is involved in the initiation or progression of breast cancer. This knowledge has to be based on a multidisciplinary approach encompassing studies of the development of the breast, influence of hormones on the differentiation of individual structures, and their interrelations in the pathogenesis of breast cancer. The analysis of the mechanisms involved would require confirmation in the adequate in vitro models and determination of the role played by genomic alterations in both cancer initiation and progression.

Lymph nodes in the human female breast: a review of their detection and significance

Our experience led us to test the hypothesis that lymph nodes are not uncommon within the substance of the human female breast mound. The following specimen types and sources were used to survey the presence of intramammary lymph nodes in the human female breast mound: (1) cadaver breasts; (2) community hospital breast specimens; and (3) university and VA hospital specimens. We found true lymph nodes within and associated with breast specific tissue (ie, tissue that includes duct and gland structures), thereby validating the hypothesis posed. We discuss the significance of these findings in terms of our dominant patient care paradigm (the Triple Test-physical examination, imaging, and fine-needle aspiration [FNA]) and the choice of patient care management options. We conclude the following: lymph nodes occur in any quadrant of the breast mound; recognizing the possibility of intramammary lymph nodes is important when choosing between patient management options; intramammary lymph nodes can be sampled by FNA; intramammary lymph nodes can contain various disease processes; and in the Oregon Health Sciences University Multidisciplinary Breast Clinic, these intramammary lymph nodes are commonly identified by imaging methods and are more likely to be sampled by FNA than either by core or excisional biopsy.

Anatomy and physiology of lactation

Milk secretion is a robust process that proceeds normally in at least 85% of women postpartum. Anecdotal evidence suggests that, with assistance in the techniques of breastfeeding, at least 97% of women can successfully breastfeed their infants. The causes of lack of success in breastfeeding are not well understood because, at least in Western societies, when infants fail to thrive on the breast, formula substitution is easy. Although this article is not the place to discuss possible pathologic mechanisms, breastfeeding failure usually occurs at approximately the first week postpartum, and a much better understanding of the mechanisms by which milk secretion is initiated during this period may help researchers to understand why some women have severe problems with lactation. The general understanding of the mechanisms of milk secretion is fairly good, but the regulatory mechanisms at the cellular and molecular levels have not been given adequate attention and are ripe for future investigation. Other areas that require attention are the behavior correlates of breastfeeding and the transfer of drugs and toxins into milk. The latter may have a long-term impact on infant health and should receive increased attention.

A 3D electrical impedance tomography (EIT) system for breast cancer detection

A medical device which allows imaging of the distribution of conductivity in 3D in regions below the skin surface has been developed and tested. Its purpose is to enable early detection and preliminary diagnosis of breast tumours. Design of the measuring system and software are described. Results of clinical evaluation of the system are presented. EIT images of healthy and cancerous breasts are presented and discussed. The system is able to visualize various states of the breast and it may be possible to apply it to breast cancer detection.