Menstrual cycle-related fluctuations in breast density measured by using three-dimensional MR imaging

Breast Glandular and Ductal Volume Changes during the Menstrual Cycle: A Study in 48 Breasts Using Ultralow-Frequency Transmitted Ultrasound Tomography/Volography

The aim of this study was to show for the first time that low-frequency 3D-transmitted ultrasound tomography (3D UT, volography) can differentiate breast tissue types using tissue properties, accurately measure glandular and ductal volumes in vivo, and measure variation over time. Data were collected for 400 QT breast scans on 24 women (ages 18-71), including four (4) postmenopausal subjects, 6-10 times over 2+ months of observation. The date of onset of menopause was noted, and the cases were further subdivided into three (3) classes: pre-, post-, and peri-menopausal. The ducts and glands were segmented using breast speed of sound, attenuation, and reflectivity images and followed over several menstrual cycles. The coefficient of variation (CoV) for glandular tissue in premenopausal women was significantly larger than for postmenopausal women, whereas this is not true for the ductal CoV. The glandular standard deviation (SD) is significantly larger in premenopausal women vs. postmenopausal women, whereas this is not true for ductal tissue. We conclude that ducts do not appreciably change over the menstrual cycle in either pre- or post-menopausal subjects, whereas glands change significantly over the cycle in pre-menopausal women, and 3D UT can differentiate ducts from glands in vivo.

Diagnostic performance of screening mammography according to menstrual cycle among Asian women

PURPOSE

To investigate the performance metrics of screening mammography according to menstrual cycle week in premenopausal Asian women.

METHODS

This retrospective study included 69,556 premenopausal Asian women who underwent their first screening mammography between 2011 and 2019. The presence or absence of a breast cancer diagnosis within 12 months after the index screening mammography served as the reference standard, determined by linking the study data to the national cancer registry data. Menstrual cycles were calculated, and participants were assigned to groups according to weeks 1-4. The performance metrics included cancer detection rate (CDR), sensitivity, specificity, and positive predictive value (PPV), with comparisons across menstrual cycles.

RESULTS

Among menstrual cycles, the lowest CDR at 4.7 per 1000 women (95% confidence interval [CI], 3.8-5.8 per 1000 women) was observed in week 4 (all P < 0.05). The highest sensitivity of 72.7% (95% CI, 61.4-82.3) was observed in week 1, although the results failed to reach statistical significance. The highest specificity of 80.4% (95% CI, 79.5-81.3%) was observed in week 1 (P = 0.01). The lowest PPV of 2.2% (95% CI, 1.8-2.7) was observed in week 4 (all P < 0.05).

CONCLUSION

Screening mammography tended to show a higher performance during week 1 and a lower performance during week 4 of the menstrual cycle among Asian women. These results emphasize the importance of timing recommendations that consider menstrual cycles to optimize the effectiveness of screening mammography for breast cancer detection.

Magnitude of radial forearm free flaps and factors associated with loss of volume in oral cancer reconstructive surgery: Prospective study

BACKGROUND

Adequate flap volume is key to maintaining oral function after oral cancer surgery. This study aimed to evaluate changes in radial forearm free flap (RFFF) volumes after 1 year of follow-up following ablative tumor surgery in the head and neck.

METHODS

A prospective study that recorded the clinical data of 20 patients with head and neck cancer who underwent RFFF reconstruction. Magnetic resonance (MR) and Mimics Research 19.0 software were used to measure the RFFF volumes at 1, 3, 6, and 12 postoperative months.

RESULTS

Compared with one postoperative month, the RFFF volume decreased by 15.5%, 29.4%, and 42.0% at 3, 6, and 12 months, respectively, after surgery. A significant positive correlation between postoperative radiotherapy and RFFF volume changes was detected.

CONCLUSION

The volume of RFFF decreases with time. It is recommended to use overcorrection, with a 40% increase in RFFF volume, to reconstruct head and neck tumor-related defects.

Harmonization of Quantitative Parenchymal Enhancement in T1 -Weighted Breast MRI

BACKGROUND

Differences in imaging parameters influence computer-extracted parenchymal enhancement measures from breast MRI.

PURPOSE

To investigate the effect of differences in dynamic contrast-enhanced MRI acquisition parameter settings on quantitative parenchymal enhancement of the breast, and to evaluate harmonization of contrast-enhancement values with respect to flip angle and repetition time.

STUDY TYPE

Retrospective.

PHANTOM/POPULATIONS

We modeled parenchymal enhancement using simulations, a phantom, and two cohorts (N = 398 and N = 302) from independent cancer centers.

SEQUENCE FIELD/STRENGTH

1.5T dynamic contrast-enhanced T1 -weighted spoiled gradient echo MRI. Vendors: Philips, Siemens, General Electric Medical Systems.

ASSESSMENT

We assessed harmonization of parenchymal enhancement in simulations and phantom by varying the MR parameters that influence the amount of T1 -weighting: flip angle (8°-25°) and repetition time (4-12 msec). We calculated the median and interquartile range (IQR) of the enhancement values before and after harmonization. In vivo, we assessed overlap of quantitative parenchymal enhancement in the cohorts before and after harmonization using kernel density estimations. Cohort 1 was scanned with flip angle 20° and repetition time 8 msec; cohort 2 with flip angle 10° and repetition time 6 msec.

STATISTICAL TESTS

Paired Wilcoxon signed-rank-test of bootstrapped kernel density estimations.

RESULTS

Before harmonization, simulated enhancement values had a median (IQR) of 0.46 (0.34-0.49). After harmonization, the IQR was reduced: median (IQR): 0.44 (0.44-0.45). In the phantom, the IQR also decreased, median (IQR): 0.96 (0.59-1.22) before harmonization, 0.96 (0.91-1.02) after harmonization. Harmonization yielded significantly (P < 0.001) better overlap in parenchymal enhancement between the cohorts: median (IQR) was 0.46 (0.37-0.58) for cohort 1 vs. 0.37 (0.30-0.44) for cohort 2 before harmonization (57% overlap); and 0.35 (0.28-0.43) vs. .0.37 (0.30-0.44) after harmonization (85% overlap).

DATA CONCLUSION

The proposed practical harmonization method enables an accurate comparison between patients scanned with differences in imaging parameters.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 4.

"Are changes in breast density during the menstrual cycle relevant? To what?"

PURPOSE

Cancers can be hidden by high breast density (BDen)- the masking effect (ME). BDen is also a modifiable and highly prevalent breast cancer risk (BCR) factor. The purposes of this study were to determine how much glandular volume (GVol), breast volume (BVol) and their ratio: BDen change during the menstrual cycle, and if these changes could affect ME or be relevant to results of interventional studies aiming to diminish BCR using these parameters as surrogates.

METHODS

We retrieved GVol, BVol and BDen data values obtained from 39,997 right mammograms performed with photon counting technique of 19,904 premenopausal women who reported their first day of last menses (FDLM). Many women had more than one study included over the years (with a different FDLM) but were not studied longitudinally. We segregated women by age (yearly), divided the menstrual cycle in 4 weeks, and assigned results with respect to the FDLM.

RESULTS

All parameters vary cyclically, with higher values in week 4 (GVol and BDen) or week 1 (BVol). Mean inter-week differences were very small for the three parameters, and diminished with age. However, especially in the youngest women, inter-week differences could be more than 10% for BDen, 15% for GVol, and 50% for BVol.

CONCLUSION

Small inter-week mean differences almost certainly rule out relevant changes to ME directly attributable to BDen. However, the possibility of large differences during the menstrual cycle in younger women, who are the ideal targets of interventional studies to diminish BCR, might distort results and should be accounted for.

Exploring Association of Breast Pain, Pregnancy, and Body Mass Index with Breast Tissue Elasticity in Healthy Women: Glandular and Fat Differences

Breast sonoelastography is a relatively novel ultrasound (US) method that enables estimation of tissue stiffness to estimate the elasticity of normal breast tissue and seek to correlate it with well-known breast cancer risk factors. Two hundred women of different age were included in the study and completed a questionnaire about personal, familiar, and reproductive history. Glandular and fatty tissue elasticity in all breast quadrants was measured by shear wave elastography (SWE). Mean elastographic values of breast tissue were calculated and compared to personal history risk factors. Elasticity of normal glandular tissue (66.4 kilopascals (kPa)) was higher than fatty tissue (26.1 kPa) in all breast quadrants and in both breasts. Lower outer quadrant (LOQ) had the lowest elasticity values of both parenchyma and fat. Higher elasticity values of breast tissue were confirmed in the left breast than in the right breast. Glandular and fat tissue elasticity negatively correlated with body mass index (BMI). Women with mastodynia had higher glandular elastographic values compared to subjects without breast pain. Nuliparity was also associated with higher elasticity of glandular breast tissue. The results of this study are promising and could, over time, contribute to a better understanding of glandular breast tissue elasticity as a potential risk factor for breast cancer.

Relationship Between Breast Ultrasound Background Echotexture and Magnetic Resonance Imaging Background Parenchymal Enhancement and the Effect of Hormonal Status Thereon

We studied the relationship between breast ultrasound background echotexture (BET) and magnetic resonance imaging (MRI) background parenchymal enhancement (BPE) and whether this relationship varied with hormonal status and amount of fibroglandular tissue (FGT) on MRI. Two hundred eighty-three Korean women (52.1 years; range = 27-79 years) with newly diagnosed primary breast cancer who underwent preoperative breast ultrasound and MRI were retrospectively studied. Background echotexture, BPE, and FGT were classified into 4 categories, and age, menopausal status, menstrual cycle regularity, and menstrual cycle stage at MRI were recorded. Background echotexture and BPE relationship was assessed overall, and in menopausal, FGT, menstrual cycle regularity, and menstrual cycle stage subgroups. Background echotexture and BPE correlated in women overall, and menopausal, FGT, and menstrual cycle subgroups and those in the first half of the cycle (all P < 0.001). Background echotexture reflects BPE, regardless of menopausal status, menstrual cycle regularity, and FGT and may be a biomarker of breast cancer risk.

Divergent Impact of Breast Cancer Laterality on Clinicopathological, Angiogenic, and Hemostatic Profiles: A Potential Role of Tumor Localization in Future Outcomes

To date, lateral differences of invasive breast cancer (IBrC) with respect to the angiogenic and hemostatic profiles were never studied. Here, we aimed to determine the relationship of tumor laterality with various clinical and pathological parameters including angiogenic and hemostatic profiles. A total of 92 women that were initially non-metastatic and treated by surgery were included in this single-center prospective study. Patients were grouped according to tumor localization. A four-year follow-up was accomplished in all patients with a 15.22% recurrence rate. An immunoassay of selected angiogenic and hemostatic parameters, as well as immunohistochemistry of estrogen and progesterone receptors, human epidermal growth factor receptor 2 (HER2), and Ki67, was comparatively performed in groups with right- and left-sided IBrC. The same analysis was carried out in a subgroup of patients with luminal A molecular subtype of cancer. Patients with right-sided tumors free of nodal involvement had a significantly longer overall survival compared to their left-sided counterparts (p = 0.0491). Additionally, right-sided tumors had a higher predisposition to be a luminal-A subtype of IBrC (p = 0.0016). Furthermore, 10% of left-sided tumors exhibited an overexpression of HER2, while only 2% patients suffering right-sided tumors displayed a positive score (p = 0.0357). Our findings revealed a significantly higher concentration of vascular endothelial growth factor (VEGF)-A (p = 0.0136), lower anti-angiogenic ratios (sVEGFR1/VEGF-A (p = 0.0208) and sVEGFR2/VEGF-A (p = 0.0068)), and elevated plasminogen activator inhibitor type 1 (PAI-1) (p = 0.0229) in patients with breast cancer localized in the left breast, regardless of the molecular subtype of IBrC. Our study showed that left-sided breast tumors without lymph node metastases demonstrate worse overall survival. Laterality of IBrC is associated with pro-angiogenic and pro-thrombotic conditions. We propose to consider laterality as a prognostic factor of IBrC.

Correcting time-intensity curves in dynamic contrast-enhanced breast MRI for inhomogeneous excitation fields at 7T

Purpose

Inhomogeneous excitation at ultrahigh field strengths (7T and above) compromises the reliability of quantified dynamic contrast‐enhanced breast MRI. This can hamper the introduction of ultrahigh field MRI into the clinic. Compensation for this non‐uniformity effect can consist of both hardware improvements and post‐acquisition corrections. This paper investigated the correctable radiofrequency transmit (B1+) range post‐acquisition in both simulations and patient data for 7T MRI.

Methods

Simulations were conducted to determine the minimum B1+ level at which corrections were still beneficial because of noise amplification. Two correction strategies leading to differences in noise amplification were tested. The effect of the corrections on a 7T patient data set (N = 38) with a wide range of B1+ levels was investigated in terms of time‐intensity curve types as well as washin, washout and peak enhancement values.

Results

In simulations assuming a common amount of T₁ saturation, the lowest B1+ level at which the SNR of the corrected images was at least that of the original precontrast image was 43% of the nominal angle. After correction, time‐intensity curve types changed in 24% of included patients, and the distribution of curve types corresponded better to the distribution found in literature. Additionally, the overlap between the distributions of washin, washout, and peak enhancement values for grade 1 and grade 2 tumors was slightly reduced.

Conclusion

Although the correctable range varies with the amount of T₁ saturation, post‐acquisition correction for inhomogeneous excitation was feasible down to B1+ levels of 43% of the nominal angle in vivo.

Breast Density Assessment in Young Women with Ultrasound based on Speed of Sound: Influence of the Menstrual Cycle

To investigate changes in breast density (BD) during the menstrual cycle in young women in comparison to inter-breast and -segment changes as well as reproducibility of a novel Speed-of-Sound (SoS) Ultrasound (US) method.SoS-US uses a conventional US system with a reflector and a software add-on to quantify SoS in the retro-mammillary, inner and outer segments of both breasts. Twenty healthy women (18-40 years) with regular menstrual cycles were scanned twice with two weeks in-between. Three of these were additionally measured twice per week for 25 days. Average SoS (m/s) and ΔSoS (segment-variation SoS; m/s) were measured. Variations between follicular and luteal phases and changes over the four-week period were assessed. Inter-examiner and inter-reader agreements were also evaluated. Variances between cycle phases, examiners and readers were compared.No significant SoS difference was observed between follicular and luteal phases for the twenty women (P = .126), and between all different days for the three more frequently measured women (P = .892). Inter-reader (ICC = 0.999) and inter-examiner (ICC = 0.990) agreements were high. The SoS variance due to menstrual variations was not significantly larger than the inter-examiner uncertainty (P = .461). Inter-reader variations were significantly smaller than menstrual and examiner variations (P < .001).SoS-US showed high inter-examiner and inter-reader reproducibility. The alterations during the menstrual cycles were not significantly larger than the confidence interval of measurements.

Quantitative Measurements of Breast Density Using Magnetic Resonance Imaging: A Systematic Review and Meta-Analysis

Breast density, a measure of dense fibroglandular tissue relative to non-dense fatty tissue, is confirmed as an independent risk factor of breast cancer. Although there has been an increasing interest in the quantitative assessment of breast density, no research has investigated the optimal technical approach of breast MRI in this aspect. Therefore, we performed a systematic review and meta-analysis to analyze the current studies on quantitative assessment of breast density using MRI and to determine the most appropriate technical/operational protocol. Databases (PubMed, EMBASE, ScienceDirect, and Web of Science) were searched systematically for eligible studies. Single arm meta-analysis was conducted to determine quantitative values of MRI in breast density assessments. Combined means with their 95% confidence interval (CI) were calculated using a fixed-effect model. In addition, subgroup meta-analyses were performed with stratification by breast density segmentation/measurement method. Furthermore, alternative groupings based on statistical similarities were identified via a cluster analysis employing study means and standard deviations in a Nearest Neighbor/Single Linkage. A total of 38 studies matched the inclusion criteria for this systematic review. Twenty-one of these studies were judged to be eligible for meta-analysis. The results indicated, generally, high levels of heterogeneity between study means within groups and high levels of heterogeneity between study variances within groups. The studies in two main clusters identified by the cluster analysis were also subjected to meta-analyses. The review confirmed high levels of heterogeneity within the breast density studies, considered to be due mainly to the applications of MR breast-imaging protocols and the use of breast density segmentation/measurement methods. Further research should be performed to determine the most appropriate protocol and method for quantifying breast density using MRI.

Menstrual Cycle-Related Fluctuations in Breast Volume Measured Using Three-Dimensional Imaging: Implications for Volumetric Evaluation in Breast Augmentation

BACKGROUND

Breast volume is a key parameter of breast measurement in breast augmentation. However, the correlation between menstrual cycle phases and variation in breast volume has not been well studied.

METHODS

Young female patients with regular menstrual cycles underwent eight three-dimensional imaging scans during a single menstrual cycle from November 2017 to January 2018. Breast volumetric difference at each timepoint and basic breast volume were measured for each subject. Preovulatory phase and postovulatory phase values were compared using an unpaired t test. A Pearson's linear correlated analysis was performed to identify the correlation between the basic breast volume and maximum range of breast volumetric difference during the menstrual cycle.

RESULTS

Thirteen patients (26 breasts) met the inclusion criteria. During the menstrual cycle, the breast volumetric difference showed first a rising trend followed by a fall. A significant difference in the breast volumetric difference between the preovulatory phase and postovulatory phase (- 19.6 ± 2.1 ml pre-ovulation vs. - 6.9 ± 3.3 ml post-ovulation, p = 0.002) was noted. There was a positive linear association between breast volume and maximum range of breast volumetric difference when a Pearson correlation was used (r = 0.45, p = 0.021).

CONCLUSIONS

The breast volume fluctuates during the menstrual cycle, and there is a significant difference between the preovulatory phase and postovulatory phase for breast volumetric change. The influence of the menstrual cycle on breast volume should be taken into consideration by plastic surgeons performing breast augmentation.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Imaging and Clinical Features of an Unusual Unilateral Breast Enlargement Diagnosed as Fibrocystic Change: A Case Report

Patient: Female, 38

Final Diagnosis: Fibrocystic change

Symptoms: Breast swelling

Medication: —

Clinical Procedure: Breast biopsy

Specialty: Radiology

A comprehensive tool for measuring mammographic density changes over time

Background

Mammographic density is a marker of breast cancer risk and diagnostics accuracy. Density change over time is a strong proxy for response to endocrine treatment and potentially a stronger predictor of breast cancer incidence. We developed STRATUS to analyse digital and analogue images and enable automated measurements of density changes over time.

Method

Raw and processed images from the same mammogram were randomly sampled from 41,353 healthy women. Measurements from raw images (using FDA approved software iCAD) were used as templates for STRATUS to measure density on processed images through machine learning. A similar two-step design was used to train density measures in analogue images. Relative risks of breast cancer were estimated in three unique datasets. An alignment protocol was developed using images from 11,409 women to reduce non-biological variability in density change. The protocol was evaluated in 55,073 women having two regular mammography screens. Differences and variances in densities were compared before and after image alignment.

Results

The average relative risk of breast cancer in the three datasets was 1.6 [95% confidence interval (CI) 1.3–1.8] per standard deviation of percent mammographic density. The discrimination was AUC 0.62 (CI 0.60–0.64). The type of image did not significantly influence the risk associations. Alignment decreased the non-biological variability in density change and re-estimated the yearly overall percent density decrease from 1.5 to 0.9%, p < 0.001.

Conclusions

The quality of STRATUS density measures was not influenced by mammogram type. The alignment protocol reduced the non-biological variability between images over time. STRATUS has the potential to become a useful tool for epidemiological studies and clinical follow-up.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4690-5) contains supplementary material, which is available to authorized users.

Longitudinal fluctuation in mammographic percent density differentiates between interval and screen-detected breast cancer

Interval breast cancer (IC) has a more aggressive phenotype and higher mortality than screen-detected cancer (SDC). In this case-case study, we investigated whether the size of longitudinal fluctuations in mammographic percent density (PD fluctuation) was associated with the ratio of IC versus SDC among screened women with breast cancer. The primary study population consisted of 1,414 postmenopausal breast cancer cases, and the validation population of 1,241 cases. We calculated PD fluctuation as the quadratic mean of deviations between actual PD and the long-term trend estimated by a mixed effects model. In a logistic regression model we examined the association between PD fluctuation and IC versus SDC including adjustments for PD at last screening, age at diagnosis, BMI and hormone replacement therapy. All statistical tests were two-sided. There were 385 IC and 1,029 SDC in the primary study population, with PD fluctuations of 0.44 and 0.41 respectively (p = 0.0309). After adjustments, PD fluctuation was associated with an increased ratio of IC versus SDC, with an estimated per-standard deviation odds ratio of 1.17 (95% CI = 1.03-1.33), compared to 1.19 (95% CI = 1.04-1.38) in the validation population. In screened women with breast cancer, high fluctuation in mammographic percent density was associated with an increased ratio of IC versus SDC. Whether this is entirely related to a reduced mammographic detectability or to a biological phenotype promoting faster tumor growth remains to be elucidated.

Impact of positional difference on the measurement of breast density using MRI

PURPOSE

This study investigated the impact of arms/hands and body position on the measurement of breast density using MRI.

METHODS

Noncontrast-enhanced T1-weighted images were acquired from 32 healthy women. Each subject received four MR scans using different experimental settings, including a high resolution hands-up, a low resolution hands-up, a high resolution hands-down, and finally, another high resolution hands-up after repositioning. The breast segmentation was performed using a fully automatic chest template-based method. The breast volume (BV), fibroglandular tissue volume (FV), and percent density (PD) measured from the four MR scan settings were analyzed.

RESULTS

A high correlation of BV, FV, and PD between any pair of the four MR scans was noted (r > 0.98 for all). Using the generalized estimating equation method, a statistically significant difference in mean BV among four settings was noted (left breast, score test p = 0.0056; right breast, score test p = 0.0016), adjusted for age and body mass index. Despite differences in BV, there were no statistically significant differences in the mean PDs among the four settings (p > 0.10 for left and right breasts). Using Bland-Altman plots, the smallest mean difference/bias and standard deviations for BV, FV, and PD were noted when comparing hands-up high vs low resolution when the breast positions were exactly the same.

CONCLUSIONS

The authors' study showed that BV, FV, and PD measurements from MRI of different positions were highly correlated. BV may vary with positions but the measured PD did not differ significantly between positions. The study suggested that the percent density analyzed from MRI studies acquired using different arms/hands and body positions from multiple centers can be combined for analysis.

Imaging Breast Density: Established and Emerging Modalities

Mammographic density has been proven as an independent risk factor for breast cancer. Women with dense breast tissue visible on a mammogram have a much higher cancer risk than women with little density. A great research effort has been devoted to incorporate breast density into risk prediction models to better estimate each individual’s cancer risk. In recent years, the passage of breast density notification legislation in many states in USA requires that every mammography report should provide information regarding the patient’s breast density. Accurate definition and measurement of breast density are thus important, which may allow all the potential clinical applications of breast density to be implemented. Because the two-dimensional mammography-based measurement is subject to tissue overlapping and thus not able to provide volumetric information, there is an urgent need to develop reliable quantitative measurements of breast density. Various new imaging technologies are being developed. Among these new modalities, volumetric mammographic density methods and three-dimensional magnetic resonance imaging are the most well studied. Besides, emerging modalities, including different x-ray–based, optical imaging, and ultrasound-based methods, have also been investigated. All these modalities may either overcome some fundamental problems related to mammographic density or provide additional density and/or compositional information. The present review article aimed to summarize the current established and emerging imaging techniques for the measurement of breast density and the evidence of the clinical use of these density methods from the literature.

Effect of menstrual cycle phase on background parenchymal uptake at molecular breast imaging

RATIONALE AND OBJECTIVES

The level of Tc-99m sestamibi uptake within normal fibroglandular tissue on molecular breast imaging (MBI), termed background parenchymal uptake (BPU), has been anecdotally observed to fluctuate with menstrual cycle. Our objective was to assess the impact of menstrual cycle phase on BPU appearance.

MATERIALS AND METHODS

Premenopausal volunteers who reported regular menstrual cycles and no exogenous hormone use were recruited to undergo serial MBI examinations during the follicular and luteal phase. A study radiologist, blinded to cycle phase, categorized BPU as photopenic, minimal mild, moderate, or marked. Change in BPU with cycle phase was determined, as well as correlations of BPU with mammographic density and hormone levels.

RESULTS

In 42 analyzable participants, high BPU (moderate or marked) was observed more often in luteal phase compared to follicular (P = .016). BPU did not change with phase in 30 of 42 participants (71%) and increased in the luteal phase compared to follicular in 12 (29%). High BPU was more frequent in dense breasts compared to nondense breasts at both the luteal (58% [15 of 26] vs. 13% [2 of 16], P = .004) and follicular phases (35% [9 of 26] vs. 6% [1 of 16], P = .061). Spearman correlation coefficients did not show any correlation of BPU with hormone levels measured at either cycle phase and suggested a weak correlation between change in BPU and changes in estrone and estradiol between phases.

CONCLUSIONS

We observed variable effects of menstrual cycle on BPU among our cohort of premenopausal women; however, when high BPU was observed, it was most frequently seen during the luteal phase compared to follicular phase and in women with dense breasts compared to nondense breasts.

Quantification of Regional Breast Density in Four Quadrants Using 3D MRI-A Pilot Study

PURPOSE: This study presented a three-dimensional magnetic resonance (MR)–based method to separate a breast into four quadrants for quantitative measurements of the quadrant breast volume (BV) and density. METHODS: Breast MR images from 58 healthy women were studied. The breast and the fibroglandular tissue were segmented by using a computer-based algorithm. A breast was divided into four quadrants using two perpendicular planes intersecting at the nipple or the nipple-centroid line. After the separation, the BV, the fibroglandular tissue volume, and the percent density (PD) were calculated. The symmetry of the quadrant BV in the left and right breasts separated by using the nipple alone, or the nipple-centroid line, was compared. RESULTS: The quadrant separation made on the basis of the nipple-centroid line showed closer BVs in four quadrants than using the nipple alone. The correlation and agreement for the BV in corresponding quadrants of the left and the right breasts were improved after the nipple-centroid reorientation. Among the four quadrants, PD was the highest in the lower outer and the lowest in the upper outer (significant than the other three) quadrants (P < .05). CONCLUSIONS: We presented a quantitative method to divide a breast into four quadrants. The reorientation based on the nipple-centroid line improved the left to right quadrant symmetry, and this may provide a better standardized method to measure quantitative quadrant density. The cancer occurrence rates are known to vary in different sites of a breast, and our method may provide a tool for investigating its association with the quantitative breast density.

Validation of electrical impedance tomography qualitative and quantitative values and comparison of the numeric pain distress score against mammography

Electrical impedance tomography (EIT) is a potential supplement for mammogram screening. This study aimed to evaluate and feasibility of EIT as opposed to mammography and to determine pain perception with both imaging methods. Women undergoing screening mammography at the Radiology Department of National University of Malaysia Medical Centre were randomly selected for EIT imaging. All women were requested to give a pain score after each imaging session. Two independent raters were chosen to define the image findings of EIT. A total of 164 women in the age range from 40 to 65-year-old participated and were divided into two groups; normal and abnormal. EIT sensitivity and specificity for rater 1 were 69.4% and 63.3, whereas for rater 2 they were 55.3% and 57.0% respectively. The reliability for each rater ranged between good to very good (p<0.05). Quantitative values of EIT showed there were significant differences in all values between groups (ANCOVA, p<0.05). Interestingly, EIT scored a median pain score of 1.51±0.75 whereas mammography scored 4.15±0.87 (Mann Whitney U test, p<0.05). From these quantitative values, EIT has the potential as a health discriminating index. Its ability to replace image findings from mammography needs further investigation.

Smaller reduction in 3D breast density associated with subsequent cancer recurrence in patients with breast cancer receiving adjuvant tamoxifen therapy

OBJECTIVE

The purpose of this study was to retrospectively investigate whether 3D breast density changes measured using MRI were associated with recurrent cancer in patients with breast cancer who received adjuvant tamoxifen.

MATERIALS AND METHODS

A search of the breast MRI database (2007-2008) revealed a dataset that included 80 women (mean age, 44 years; range, 27-68 years) with breast cancer who underwent breast-conserving surgery, adjuvant tamoxifen treatment, and breast MRI before and after tamoxifen. The following clinicopathologic variables were collected: age, body mass index, menopausal status, family history, tumor stage, tumor grade, hormonal receptor status, and adjuvant chemotherapy status. MRI variables (total breast volume, fibro-glandular volume, and breast density) were measured for the contralateral untreated breast before and after tamoxifen treatment, and the percentage changes were recorded. A multivariate logistic regression analysis was performed to identify independent factors that were associated with cancer recurrence.

RESULTS

Overall, 12 (15%) of the 80 women developed recurrence. No recurrent cancers were found in the remaining 68 patients (85%) at a median follow-up of 48 months (range, 37-60 months). Percentage reduction of breast density after tamoxifen was the only independent factor associated with recurrence (adjusted odds ratio [OR] = 0.848, 95% CI = 0.769-0.935, and p = 0.001 for observer 1; adjusted OR = 0.957, 95% CI = 0.919-0.996, and p = 0.032 for observer 2) in the multivariate analysis.

CONCLUSION

Three-dimensional breast density changes measured using MRI during tamoxifen treatment were an independent factor associated with cancer recurrence in patients with breast cancer who received adjuvant tamoxifen.

Effect of taxane-based neoadjuvant chemotherapy on fibroglandular tissue volume and percent breast density in the contralateral normal breast evaluated by 3T MR

The aim of this study was to evaluate the change of breast density in the normal breast of patients receiving neoadjuvant chemotherapy (NAC). Forty-four breast cancer patients were studied. MRI acquisition was performed before treatment (baseline), and 4 and 12 weeks after treatment. A computer-algorithm-based program was used to segment breast tissue and calculate breast volume (BV), fibroglandular tissue volume (FV), and percent density (PD) (the ratio of FV over BV × 100%). The reduction of FV and PD after treatment was compared with baseline using paired t-tests with a Bonferroni-Holm correction. The association of density reduction with age was analyzed. FV and PD after NAC showed significant decreases compared with the baseline. FV was 110.0 ml (67.2, 189.8) (geometric mean (interquartile range)) at baseline, 104.3 ml (66.6, 164.4) after 4 weeks (p < 0.0001), and 94.7 ml (60.2, 144.4) after 12 weeks (comparison with baseline, p < 0.0001; comparison with 4 weeks, p = 0.016). PD was 11.2% (6.4, 22.4) at baseline, 10.6% (6.6, 20.3) after 4 weeks (p < 0.0001), and 9.7% (6.2, 17.9) after 12 weeks (comparison with baseline, p = 0.0001; comparison with 4 weeks, p = 0.018). Younger patients tended to show a higher density reduction, but overall correlation with age was only moderate (r = 0.28 for FV, p = 0.07, and r = 0.52 for PD, p = 0.0003). Our study showed that breast density measured from MR images acquired at 3T MR can be accurately quantified using a robust computer-aided algorithm based on non-parametric non-uniformity normalization (N3) and an adaptive fuzzy C-means algorithm. Similar to doxorubicin and cyclophosphamide regimens, the taxane-based NAC regimen also caused density atrophy in the normal breast and showed reduction in FV and PD. The effect of breast density reduction was age related and duration related.

Background parenchymal enhancement in the contralateral normal breast of patients undergoing neoadjuvant chemotherapy measured by DCE-MRI

The purpose of this study was to analyze background parenchymal enhancement (BPE) in the contralateral normal breast of cancer patients during the course of neoadjuvant chemotherapy (NAC). Forty-five subjects were analyzed. Each patient had three MRIs, one baseline (B/L) and two follow-up (F/U) studies. The fibroglandular tissue in the contralateral normal breast was segmented using a computer-assisted algorithm. Based on the segmented fibroglandular tissue, BPE was calculated. BPE measured in baseline (B/L) and follow-up (F/U) MR studies were compared. The baseline BPE was also correlated with age and compared between pre/peri-menopausal (<55 years old) and post-menopausal women (≥55 years old). The pre-treatment BPE measured in B/L MRI was significantly higher in women <55 years old than in women ≥55 years old (20.1%±7.4% vs. 12.1%±5.1%, p≤0.01). A trend of negative correlation between BPE and age was noted (r=-0.29). In women <55years old, BPE at F/U-1 (18.8%±6.9%) was decreased compared to B/L, and was further decreased in F/U-2 (13.3%±5.7%) which was significant compared to B/L and F/U-1. In women ≥55 years old, no significant difference was noted in any paired comparison among B/L, F/U-1 and F/U-2 MRI. A higher baseline BPE was associated with a greater reduction of BPE in F/U-2 MRI (r=0.73). Our study showed that younger women tended to have higher BPE than older women. BPE was significantly decreased in F/U-2 MRI after NAC in women <55 years old. The reduction in BPE was most likely due to the ovarian ablation induced by chemotherapeutic agents.

Correlation of endogenous hormonal levels, fibroglandular tissue volume and percent density measured using 3D MRI during one menstrual cycle

BACKGROUND

We measured breast density (BD) on MRI and correlated with endogenous hormonal levels.

PATIENTS AND METHODS

Twenty-four premenopausal women received four weekly breast MRI. A blood sample was collected on the same day of MRI. BD was measured using a computer-based algorithm. The generalized estimation equation method was applied to model mean fibroglandular tissue volume (FV) and mean percent density (PD) from predictor variables including estradiol, progesterone, and week during a cycle.

RESULTS

In week 3, a borderline significant correlation between estradiol and PD (r = 0.43, P = 0.04), estradiol and FV (r = 0.40, P = 0.05) and between progesterone and FV (r = 0.42, P = 0.04) was noted. The FV and PD measured in weeks 4 and 1 were higher than in weeks 2 and 3, adjusted for variation in endogenous estradiol and progesterone, indicating that the hormone change could not account for the changes in density. No lag effect of endogenous hormone on the change of FV or PD was noted (all P-values > 0.05).

CONCLUSIONS

Our results showed that BD is not strongly associated with the endogenous hormone. Their association with breast cancer risk was likely coming from different mechanisms, and they should be considered as independent risk factors.

Diet across the Lifespan and the Association with Breast Density in Adulthood

Studies have shown inconsistent results regarding the association between dietary factors across the lifespan and breast density and breast cancer in women. Breast density is a strong risk factor for breast cancer, and the mechanism through which it influences cancer risk remains unclear. Breast density has been shown to be modifiable, potentially through dietary modifications. The goal of this paper is to summarize the current studies on diet and diet-related factors across all ages, determine which dietary factors show the strongest association with breast density, the most critical age of exposure, and identify future directions. We identified 28 studies, many of which are cross-sectional, and found that the strongest associations are among vitamin D, calcium, dietary fat, and alcohol in premenopausal women. Longitudinal studies with repeated dietary measures as well as the examination of overall diet over time are needed to confirm these findings.

Comparison of 3-point Dixon imaging and fuzzy C-means clustering methods for breast density measurement

PURPOSE

To assess two methods of fat and fibroglandular tissue (FGT) segmentation for measuring breast MRI FGT volume and FGT%, the volume percentage of FGT in the breast, in longitudinal studies.

MATERIALS AND METHODS

Nine premenopausal women provided one MRI per week for 4 weeks during a natural menstrual cycle for a total of 36 datasets. We compared a fuzzy c-means (FC) and a 3-point Dixon segmentation method for estimation of changes in FGT volume and FGT% across the menstrual cycle. We also assessed whether differences due to changes in positioning each week could be minimized by coregistration, i.e., the application of the breast boundary selected at one visit to images obtained at other visits.

RESULTS

FC and Dixon FGT volume were highly correlated (r = 0.93, P < 0.001), as was FC and Dixon FGT% (r = 0.86, P = 0.01), although Dixon measurements were on average 10-20% higher. Although FGT measured by both methods showed the expected pattern of increase during the menstrual cycle, the magnitude, and for one woman the direction, of change varied according to the method used. Measurements of FGT for coregistered images were in close agreement with those for which the boundaries were determined independently.

CONCLUSION

The method of segmentation of fat and FGT tissue may have an impact on the results of longitudinal studies of changes in breast MRI FGT.

Response of bilateral breasts to the endogenous hormonal fluctuation in a menstrual cycle evaluated using 3D MRI

The normal breast tissue responds to the fluctuation of endogenous hormones during a menstrual cycle (MC) and shows changes in breast density. The changes between left and right breasts of the same women were compared to evaluate the symmetrical response. Twenty-four healthy women were recruited in this study. Four weekly magnetic resonance imaging (MRI) studies were performed during one MC. A computer algorithm was used to segment the breast and the fibroglandular tissue to measure the fibroglandular tissue volume (FV) and three morphological parameters: circularity, convexity and irregularity. The coefficient of variation (CV) for each parameter measured among four MRI studies was calculated; also, the maximal percent change between two MRI studies that show the highest and the lowest FV was calculated. These parameters measured from left and right breasts were compared using Pearson correlation. For the FV, the CV measured between left and right breasts of 24 subjects was highly correlated, with r=0.91; the maximal percent difference was also highly correlated, with r=0.93. Overall, the mean left-to-right difference in the measured FV was small: 1.2%±1.1% for CV and 2.6%±2.3% for the maximal percent difference. For the three morphological parameters, the mean left-to-right percentage difference was similar to the differences seen in FV; however, these morphological parameters do not reveal a high functional symmetry between left and right breasts. The results showed that the measured FV from left and right breasts of the same woman revealed a high functional symmetry. Since endogenous hormone plays an important role in the development of breast cancer, it would be interesting to investigate whether the functional asymmetry of response in some patients is associated with the risk of developing unilateral breast cancer.

Consistency of breast density measured from the same women in four different MR scanners

PURPOSE

To compare the breast volume (BV), fibroglandular tissue volume (FV), and percent density (PD) measured from breast MRI of the same women using four different MR scanners.

METHODS

The study was performed in 34 healthy Asian volunteers using two 1.5T (GE and Siemens) and two 3T (GE and Philips) MR scanners. The BV, FV, and PD were measured on nonfat-suppressed T1-weighted images using a comprehensive computer algorithm-based segmentation method. The scanner-to-scanner measurement difference, and the coefficient of variation (CV) among the four scanners were calculated. The measurement variation between two density morphological patterns presenting as the central type and the intermingled type was separately analyzed and compared.

RESULTS

All four scanners provided satisfactory image quality allowing for successful completion of the segmentation processes. The measured parameters between each pair of MR scanners were highly correlated, with R(2) ≥ 0.95 for BV, R(2) ≥ 0.99 for FV, and R(2) ≥ 0.97 for PD in all comparisons. The mean percent differences between each pair of scanners were 5.9%-7.8% for BV, 5.3%-6.5% for FV, 4.3%-7.3% for PD; with the overall CV of 5.8% for BV, 4.8% for FV, and 4.9% for PD. The variation of FV was smaller in the central type than in the intermingled type (p = 0.04).

CONCLUSIONS

The results showed that the variation of FV and PD measured from four different MR scanners is around 5%, suggesting the parameters measured using different scanners can be used for a combined analysis in a multicenter study.

Height, adiposity and body fat distribution and breast density in young women

Introduction

Breast density is one of the strongest risk factors for breast cancer, but determinants of breast density in young women remain largely unknown.

Methods

Associations of height, adiposity and body fat distribution with percentage dense breast volume (%DBV) and absolute dense breast volume (ADBV) were evaluated in a cross-sectional study of 174 healthy women, 25 to 29 years old. Adiposity and body fat distribution were measured by anthropometry and dual-energy X-ray absorptiometry (DXA), while %DBV and ADBV were measured by magnetic resonance imaging. Associations were evaluated using linear mixed-effects models. All tests of statistical significance are two-sided.

Results

Height was significantly positively associated with %DBV but not ADBV; for each standard deviation (SD) increase in height, %DBV increased by 18.7% in adjusted models. In contrast, all measures of adiposity and body fat distribution were significantly inversely associated with %DBV; a SD increase in body mass index (BMI), percentage fat mass, waist circumference and the android:gynoid fat mass ratio (A:G ratio) was each associated significantly with a 44.4 to 47.0% decrease in %DBV after adjustment for childhood BMI and other covariates. Although associations were weaker than for %DBV, all measures of adiposity and body fat distribution also were significantly inversely associated with ADBV before adjustment for childhood BMI. After adjustment for childhood BMI, however, only the DXA measures of percentage fat mass and A:G ratio remained significant; a SD increase in each was associated with a 13.8 to 19.6% decrease in ADBV. In mutually adjusted analysis, the percentage fat mass and the A:G ratio remained significantly inversely associated with %DBV, but only the A:G ratio was significantly associated with ADBV; a SD increase in the A:G ratio was associated with an 18.5% decrease in ADBV.

Conclusion

Total adiposity and body fat distribution are independently inversely associated with %DBV, whereas in mutually adjusted analysis only body fat distribution (A:G ratio) remained significantly inversely associated with ADBV in young women. Research is needed to identify biological mechanisms underlying these associations.

Contrast enhancement kinetics of normal breast parenchyma in dynamic MR mammography: effects of menopausal status, oral contraceptives, and postmenopausal hormone therapy

OBJECTIVES

To investigate effects of menopausal status, oral contraceptives (OC), and postmenopausal hormone therapy (HT) on normal breast parenchymal contrast enhancement (CE) and non-mass-like enhancing areas in magnetic resonance mammography (MRM).

METHODS

A total of 459 female volunteers (mean age 49.1 ± 12.5 years) underwent T1-weighted 3D MRM 1-5 min after bolus injection of gadobutrol. Quantitative analysis was performed in normal breast parenchyma by manually tracing regions of interest and calculating percentage CE. Semiquantitative analysis was performed in non-mass-like enhancing areas, and signal intensity changes were characterised by five predefined kinetic curve types. The influence of OC (n = 69) and HT (n = 24) on CE was studied using random effects models.

RESULTS

Breast parenchymal enhancement was significantly higher in premenopausal than in postmenopausal women (P < 0.001). CE decreased significantly with the use of OC (P = 0.01), while HT had negligible effects (P = 0.52). Prevalence of kinetic curve types of non-mass-like enhancement differed strongly between pre- and postmenopausal women (P < 0.0001), but was similar in OC users and non-OC users (P = 0.61) as well as HT users and non-HT users (P = 0.77).

CONCLUSIONS

Normal breast parenchymal enhancement and non-mass-like enhancing areas were strongly affected by menopausal status, while they were not affected by HT use and only moderately by OC use.

KEY POINTS

Breast parenchymal enhancement at MR mammography is stronger in premenopausal than postmenopausal women. The prevalence of strong enhancing non-mass-like areas is greater before menopause. Such enhancing non-mass-like areas may impair lesion detection in premenopausal women. Breast parenchymal enhancement is only marginally affected by hormone use. Discontinuation of hormone use before MR mammography may be unnecessary.