Papers by Avice O'Connell
Medical Physics, 2012
ABSTRACT Purpose: To test the hypothesis that the mean skin thickness determined using cone-beam ... more ABSTRACT Purpose: To test the hypothesis that the mean skin thickness determined using cone-beam dedicated breast CT varied between breasts with malignant, hyperplasia and benign pathology, and to determine the appropriate skin thickness for Monte Carlo based estimation of normalized glandular dose coefficients. Methods: Breast skin thickness was estimated in 137 women scheduled for biopsy (BI-RADS 4 or 5), who underwent unilateral cone-beam dedicated CT of the breast to be biopsied, after providing written informed consent and in adherence to an IRB-approved protocol. Pathology results were available for 132 women and there were 38 malignancies. A previously reported method [Huang et al., Med Phys 35(4): 1199-206, 2008] was applied to coronal (transverse) images reconstructed to 0.273 mm voxel size. The accuracy of the method was determined by imaging two phantoms of differing wall thickness and shape. For each breast, the mean, intra-breast standard deviation (SD) and the median skin thickness were computed. The mean skin thickness and associated confidence intervals (CI) in our study population were obtained from the mean skin thickness of each breast. Results: The estimated mean wall thicknesses for both phantoms were within +/-1% of the measured thickness. At the 0.05 level (ANOVA), the skin thickness means did not vary significantly with pathology (p=0.61). For each breast, the median, mean and intra-breast SD, in mm, were in the range [0.87,2.23], [0.87,2.34], and [0.22,0.85], respectively. From all 137 women, the mean +/- inter-breast SD and 95% CI were 1.44+/-0.25 and [1.40,1.48], respectively. Conclusions: The skin thickness means were not different between breasts with malignant and non-malignant pathology. Our estimate of mean skin thickness is in agreement with a previous report. Skin thickness of approximately 1.45 mm, rather than the standard 4 mm [Wu et al., Radiology 193:83-9, 1994], is appropriate for Monte Carlo based determination of normalized glandular dose coefficients. Supported in part by the National Institutes of Health (NIH) grants R01 CA128906 and R21 CA134129. The contents are solely the responsibility of the authors and do not represent the official views of the NIH or NCI.
Diagnostic and Interventional Radiology, 2012
Enlargement of lymph nodes can be due to a variety of benign and malignant causes. The most commo... more Enlargement of lymph nodes can be due to a variety of benign and malignant causes. The most common malignant cause is invasive ductal carcinoma, which is usually visualized with mammography. Excluding breast cancer, other causes of abnormal lymph nodes that produce a negative mammogram include lymphoma, metastases from other malignancies, and benign etiologies such as inflammatory processes, infectious diseases, collagen vascular diseases, and miscellaneous causes. In this essay, we described common causes of abnormal axillary lymph nodes on negative mammograms excluding breast cancer.
2022 IEEE International Ultrasonics Symposium (IUS)
Journal of Ultrasound in Medicine
Journal of Breast Imaging, 2021
European Radiology, 2020
Objectives To investigate the association of contrast-enhanced cone beam breast CT (CE-CBBCT) fea... more Objectives To investigate the association of contrast-enhanced cone beam breast CT (CE-CBBCT) features, immunohistochemical (IHC) receptors, and molecular subtypes in breast cancer. Methods In this retrospective study, patients who underwent preoperative CE-CBBCT and received complete IHC results were analyzed. CE-CBBCT features were evaluated by two radiologists. Observer reproducibility and feature reliability were assessed. The association between CE-CBBCT features, IHC receptors, and molecular subtypes was analyzed using the chi-square, Mann-Whitney, and Kruskal-Wallis tests. Multivariate logistic regression was performed to assess the ability of combined imaging features to discriminate molecular subtypes. ROC curve was used to evaluate prediction performance. Results A total of 240 invasive cancers identified in 211 women were enrolled. Molecular subtypes of breast cancer were significantly associated with focality number of lesions, lesion type, tumor size, lesion density, internal enhancement pattern, degree of lesion enhancement (ΔHU), mass shape, spiculation, calcifications, calcification distribution, and increased peripheral vascularity of lesion (all p < 0.005), some of which also helped to differentiate IHC receptor status. A multivariate logistic regression model showed that tumor size (odds ratio, OR = 1.244), mass shape (OR = 0.311), spiculation (OR = 0.159), and internal enhancement pattern (OR = 0.227) were associated with differentiation between luminal and non-luminal subtypes (AUC = 0.809). Combined CE-CBBCT features, including lesion type (OR = 0.118), calcifications (OR = 0.181), and ΔHU (OR = 0.962), could be significant indicators of triple-negative versus HER-2-enriched subtypes (AUC = 0.913). Conclusions CE-CBBCT features have the potential to help predict IHC receptor status and distinguish molecular subtypes of breast cancer, which could in turn help to develop individual treatment decisions and prognosis predictions. Key Points • A total of 11 CE-CBBCT features were associated with molecular subtypes, some of which also helped to differentiate IHC receptor status. • Tumor size, irregular mass shape, spiculation, and internal enhancement pattern could help identify luminal subtype. • Lesion type, calcification, and ΔHU could be significant indicators of HER-2-enriched versus triple-negative breast cancers.
European Radiology, 2021
Dedicated breast CT is being increasingly used for breast imaging. This technique provides images... more Dedicated breast CT is being increasingly used for breast imaging. This technique provides images with no compression, removal of tissue overlap, rapid acquisition, and available simultaneous assessment of microcalcifications and contrast enhancement. In this second installment in a 2-part review, the current status of clinical applications and ongoing efforts to develop new imaging systems are discussed, with particular emphasis on how to achieve optimized practice including lesion detection and characterization, response to therapy monitoring, density assessment, intervention, and implant evaluation. The potential for future screening with breast CT is also addressed. • Dedicated breast CT is an emerging modality with enormous potential in the future of breast imaging by addressing numerous clinical needs from diagnosis to treatment. • Breast CT shows either noninferiority or superiority with mammography and numerical comparability to MRI after contrast administration in diagnostic statistics, demonstrates excellent performance in lesion characterization, density assessment, and intervention, and exhibits promise in implant evaluation, while potential application to breast cancer screening is still controversial. • New imaging modalities such as phase-contrast breast CT, spectral breast CT, and hybrid imaging are in the progress of R & D.
Breast Diseases: A Year Book Quarterly, 2012
Ultrasound Quarterly, 2013
Metastases to the thyroid gland are uncommon. We present the sonographic features of metastatic b... more Metastases to the thyroid gland are uncommon. We present the sonographic features of metastatic breast adenocarcinoma to the thyroid in a 67-year-old woman. The lesion measured up to 0.9 cm in diameter, contained an echogenic focus with associated ring-down, and was predominantly cystic, thereby resembling a benign nodule. Because of the patient's history of breast adenocarcinoma, the nodule nevertheless underwent fine-needle aspiration. The unusual appearance of the thyroid nodule underscores the importance of considering patient history in deciding whether obtaining tissue diagnosis of thyroid nodules is warranted.
Medical Physics, 2013
To determine the mean and range of location-averaged breast skin thickness using highresolution d... more To determine the mean and range of location-averaged breast skin thickness using highresolution dedicated breast CT for use in Monte Carlo-based estimation of normalized glandular dose coefficients. Methods: This study retrospectively analyzed image data from a clinical study investigating dedicated breast CT. An algorithm similar to that described by Huang et al. ["The effect of skin thickness determined using breast CT on mammographic dosimetry," Med. Phys. 35(4), 1199-1206 (2008)] was used to determine the skin thickness in 137 dedicated breast CT volumes from 136 women. The location-averaged mean breast skin thickness for each breast was estimated and the study population mean and range were determined. Pathology results were available for 132 women, and were used to investigate if the distribution of location-averaged mean breast skin thickness varied with pathology. The effect of surface fitting to account for breast curvature was also studied. Results: The study mean (± interbreast SD) for breast skin thickness was 1.44 ± 0.25 mm (range: 0.87-2.34 mm), which was in excellent agreement with Huang et al. Based on pathology, pair-wise statistical analysis (Mann-Whitney test) indicated that at the 0.05 significance level, there were no significant difference in the location-averaged mean breast skin thickness distributions between the groups: benign vs malignant (p = 0.223), benign vs hyperplasia (p = 0.651), hyperplasia vs malignant (p = 0.229), and malignant vs nonmalignant (p = 0.172). Conclusions: Considering this study used a different clinical prototype system, and the study participants were from a different geographical location, the observed agreement between the two studies suggests that the choice of 1.45 mm thick skin layer comprising the epidermis and the dermis for breast dosimetry is appropriate. While some benign and malignant conditions could cause skin thickening, in this study cohort the location-averaged mean breast skin thickness distributions did not differ significantly with pathology. The study also underscored the importance of considering breast curvature in estimating breast skin thickness.
Medical Physics, 2013
To determine the mean and range of location-averaged breast skin thickness using highresolution d... more To determine the mean and range of location-averaged breast skin thickness using highresolution dedicated breast CT for use in Monte Carlo-based estimation of normalized glandular dose coefficients. Methods: This study retrospectively analyzed image data from a clinical study investigating dedicated breast CT. An algorithm similar to that described by Huang et al. ["The effect of skin thickness determined using breast CT on mammographic dosimetry," Med. Phys. 35(4), 1199-1206 (2008)] was used to determine the skin thickness in 137 dedicated breast CT volumes from 136 women. The location-averaged mean breast skin thickness for each breast was estimated and the study population mean and range were determined. Pathology results were available for 132 women, and were used to investigate if the distribution of location-averaged mean breast skin thickness varied with pathology. The effect of surface fitting to account for breast curvature was also studied. Results: The study mean (± interbreast SD) for breast skin thickness was 1.44 ± 0.25 mm (range: 0.87-2.34 mm), which was in excellent agreement with Huang et al. Based on pathology, pair-wise statistical analysis (Mann-Whitney test) indicated that at the 0.05 significance level, there were no significant difference in the location-averaged mean breast skin thickness distributions between the groups: benign vs malignant (p = 0.223), benign vs hyperplasia (p = 0.651), hyperplasia vs malignant (p = 0.229), and malignant vs nonmalignant (p = 0.172). Conclusions: Considering this study used a different clinical prototype system, and the study participants were from a different geographical location, the observed agreement between the two studies suggests that the choice of 1.45 mm thick skin layer comprising the epidermis and the dermis for breast dosimetry is appropriate. While some benign and malignant conditions could cause skin thickening, in this study cohort the location-averaged mean breast skin thickness distributions did not differ significantly with pathology. The study also underscored the importance of considering breast curvature in estimating breast skin thickness.
Medical Physics, 2012
Purpose: To determine the mean and range of volumetric glandular fraction (VGF) of the breast in ... more Purpose: To determine the mean and range of volumetric glandular fraction (VGF) of the breast in a diagnostic population using a high-resolution flat-panel cone-beam dedicated breast CT system. This information is important for Monte Carlo-based estimation of normalized glandular dose coefficients and for investigating the dependence of VGF on breast dimensions, race, and pathology. Methods: Image data from a clinical trial investigating the role of dedicated breast CT that enrolled 150 women were retrospectively analyzed to determine the VGF. The study was conducted in adherence to a protocol approved by the institutional human subjects review boards and written informed consent was obtained from all study participants. All participants in the study were assigned BI-RADS R 4 or 5 as per the American College of Radiology assessment categories after standard diagnostic work-up and underwent dedicated breast CT exam prior to biopsy. A Gaussian-kernel based fuzzy c-means algorithm was used to partition the breast CT images into adipose and fibroglandular tissue after segmenting the skin. Upon determination of the accuracy of the algorithm with a phantom, it was applied to 137 breast CT volumes from 136 women. VGF was determined for each breast and the mean and range were determined. Pathology results with classification as benign, malignant, and hyperplasia were available for 132 women, and were used to investigate if the distributions of VGF varied with pathology. Results: The algorithm was accurate to within ±1.9% in determining the volume of an irregular shaped phantom. The study mean (± inter-breast SD) for the VGF was 0.172 ± 0.142 (range: 0.012-0.719). VGF was found to be negatively correlated with age, breast dimensions (chest-wall to nipple length, pectoralis to nipple length, and effective diameter at chest-wall), and total breast volume, and positively correlated with fibroglandular volume. Based on pathology, pairwise statistical analysis (Mann-Whitney test) indicated that at the 0.05 significance level, there was no significant difference in distributions of VGF without adjustment for age between malignant and nonmalignant breasts (p = 0.41). Pairwise comparisons of the distributions of VGF in increasing order of mammographic breast density indicated all comparisons were statistically significant (p < 0.002). Conclusions: This study used a different clinical prototype breast CT system than that in previous studies to image subjects from a different geographical region, and used a different algorithm for analysis of image data. The mean VGF estimated from this study is within the range reported in previous studies, indicating that the choice of 50% glandular weight fraction to represent an average breast for Monte Carlo-based estimation of normalized glandular dose coefficients in mammography needs revising. In the study, the distributions of VGF did not differ significantly with pathology.
Breast Imagers are regularly requested to perform imaging exams for women outside the typical coh... more Breast Imagers are regularly requested to perform imaging exams for women outside the typical cohort of patients in their 40s and older age groups. It is important for referring providers to know what imaging exam to order, what to expect, and how to follow up such patients. This chapter discusses the role of imaging in the management of breast symptoms in the teenage, the pregnant, the lactating women, and the transgender population and special challenges in diagnosing young women with breast cancer. During pregnancy and lactation, physiologic changes induced by pregnancy and lactation-associated hormonal changes pose a unique challenge in both the clinical assessment and in the differential diagnosis of imaging findings. There is increased susceptibility to infections during lactation. Pregnancy-associated breast cancer is the most invasive cancer affecting pregnant women, and delayed diagnosis may result in cancer being at a more advanced stage. Some of the benign tumors encounte...
Journal of Breast Imaging
In the United States, at least 1.4 million adults identify as transgender. Despite growing nation... more In the United States, at least 1.4 million adults identify as transgender. Despite growing national awareness, the transgender population experiences disparities in breast care access and breast health outcomes. One of the challenges of breast care delivery to transgender patients is the lack of evidence-based screening guidelines, which is likely partly due to the infrequency of transgender breast cancer cases. Several gender-affirming hormonal and surgical interventions are available that impact the imaging appearance of the breasts and the risk of breast cancer. Breast imaging radiologists should be familiar with the imaging appearance of expected findings and potential complications following gender-affirming interventions. It has been shown that the incidence of breast cancer in transgender women is higher than in natal males but still lower than in natal females, implying that estrogen supplementation confers an increased breast cancer risk. It is proposed that transgender wom...
Journal of Ultrasound in Medicine
Objectives-We study the performance of an artificial intelligence (AI) program designed to assist... more Objectives-We study the performance of an artificial intelligence (AI) program designed to assist radiologists in the diagnosis of breast cancer, relative to measures obtained from conventional readings by radiologists. Methods-A total of 10 radiologists read a curated, anonymized group of 299 breast ultrasound images that contained at least one suspicious lesion and for which a final diagnosis was independently determined. Separately, the AI program was initialized by a lead radiologist and the computed results compared against those of the radiologists. Results-The AI program's diagnoses of breast lesions had concordance with the 10 radiologists' readings across a number of BI-RADS descriptors. The sensitivity, specificity, and accuracy of the AI program's diagnosis of benign versus malignant was above 0.8, in agreement with the highest performing radiologists and commensurate with recent studies. Conclusion-The trained AI program can contribute to accuracy of breast cancer diagnoses with ultrasound.
Seminars in Ultrasound, CT and MRI
Dedicated breast computed tomography (CT) is the latest in a long history of breast imaging techn... more Dedicated breast computed tomography (CT) is the latest in a long history of breast imaging techniques dating back to the 1960s. Breast imaging is performed both for cancer screening as well as for diagnostic evaluation of symptomatic patients. Dedicated breast CT received US Food and Drug Administration approval for diagnostic use in 2015 and is slowly gaining recognition for its value in diagnostic 3-dimensional imaging of the breast, and also for injected contrast-enhanced imaging applications. Conventional mammography has known limitations in sensitivity and specificity, especially in dense breasts. Breast tomosynthesis was US Food and Drug Administration approved in 2011 and is now widely used. Dedicated breast CT is the next technological advance, combining real 3-dimensional imaging with the ease of contrast administration. The lack of painful compression and manipulation of the breasts also makes dedicated breast CT much more acceptable for the patients.
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Papers by Avice O'Connell