Patient Communication Innovations in Breast Imaging.

Effective patient communication is paramount in breast radiology, where standardized reporting and patient-centered care practices have long been established. This communication profoundly affects patient experience, well-being, and adherence to medical advice. Breast radiologists play a pivotal role in conveying diagnostic findings and addressing patient concerns, particularly in the context of cancer diagnoses. Technological advances in radiology reporting, patient access to electronic medical records, and the demand for immediate information access have reshaped radiologists' communication practices. Innovative approaches, including image-rich reports, visual timelines, and video radiology reports, have been used in various institutions to enhance patient comprehension and engagement.

NCCN Guidelines® Insights: Breast Cancer Screening and Diagnosis, Version 1.2023.

The NCCN Guidelines for Breast Cancer Screening and Diagnosis provide health care providers with a practical, consistent framework for screening and evaluating a spectrum of clinical presentations and breast lesions. The NCCN Breast Cancer Screening and Diagnosis Panel is composed of a multidisciplinary team of experts in the field, including representation from medical oncology, gynecologic oncology, surgical oncology, internal medicine, family practice, preventive medicine, pathology, diagnostic and interventional radiology, as well as patient advocacy. The NCCN Breast Cancer Screening and Diagnosis Panel meets at least annually to review emerging data and comments from reviewers within their institutions to guide updates to existing recommendations. These NCCN Guidelines Insights summarize the panel's decision-making and discussion surrounding the most recent updates to the guideline's screening recommendations.

Model observer performance in contrast-enhanced lesions in breast CT: The influence of contrast concentration on detectability.

BACKGROUND: The use of iodine-based contrast agent for better delineation of tumors in breast CT (bCT) has been shown to be compelling, similar to the tumor enhancement in contrast-enhanced breast MRI. Contrast-enhanced bCT (CE-bCT) is a relatively new tool, and a structured evaluation of different imaging parameters at play has yet to be conducted. In this investigation, data sets of acquired bCT images from 253 patients imaged at our institution were used in concert with simulated mathematically inserted spherical contrast-enhanced lesions to study the role of contrast enhancement on detectability. PURPOSE: To quantitatively evaluate the improvement in lesion detectability due to contrast enhancement across lesion diameter, section thickness, view plane, and breast density using a pre-whitened matched filter (PWMF) model observer. METHODS: The relationship between iodine concentration and Hounsfield units (HU) was measured using spectral modeling. The lesion enhancement from clinical CE-bCT images in 22 patients was evaluated, and the average contrast enhancement (ΔHU) was determined. Mathematically generated spherical mass lesions of varying diameters (1, 3, 5, 9, 11, 15 mm) and contrast enhancement levels (0, 0.25, 0.50, 0.75, 1) were inserted at random locations in 253 actual patient bCT datasets. Images with varying thicknesses (0.4-19.8 mm) were generated by slice averaging, and the role of view plane (coronal and axial planes) was studied. A PWMF was used to generate receiver operating characteristic (ROC) curves across parameters of lesion diameter, contrast enhancement, section thickness, view plane, and breast density. The area under the ROC curve (AUC) was used as the primary performance metric, generated from over 90,000 simulated lesions. RESULTS: An average 20% improvement (ΔAUC = 0.1) in lesion detectability due to contrast enhancement was observed across lesion diameter, section thickness, breast density, and view plane. A larger improvement was observed when stratifying patients based on breast density. For patients with VGF ≤ 40%, detection performance improved up to 20% (until AUC →1), and for patients with denser breasts (VGF > 40%), detection performance improved more drastically, ranging from 20% to 80% for 1- and 5-mm lesions. For the 1 mm lesion, detection performance raised slightly at the 1.2 mm section thickness before falling off as thickness increased. For larger lesions, detection performance was generally unaffected as section thickness increased up until it reached 5.8 mm, where performance began to decline. Detection performance was higher in the axial plane compared to the coronal plane for smaller lesions and thicker sections. CONCLUSIONS: For emerging diagnostic tools like CE-bCT, it is important to optimize imaging protocols for lesion detection. In this study, we found that intravenous contrast can be used to detect small lesions in dense breasts. Optimal section thickness for detectability has dependencies on breast density and lesion size, therefore, display thickness should be adjusted in real-time using display software. These findings may be useful for the development of CE-bCT as well as other x-ray-based breast imaging modalities.

Impact of the COVID-19 Pandemic on Breast Imaging Education.

OBJECTIVE: To determine the impact of the COVID-19 pandemic on breast imaging education. METHODS: A 22-item survey addressing four themes during the early pandemic (time on service, structured education, clinical training, future plans) was emailed to Society of Breast Imaging members and members-in-training in July 2020. Responses were compared using McNemar's and Mann-Whitney U tests; a general linear model was used for multivariate analysis. RESULTS: Of 136 responses (136/2824, 4.8%), 96 U.S. responses from radiologists with trainees, residents, and fellows were included. Clinical exposure declined during the early pandemic, with almost no medical students on service (66/67, 99%) and fewer clinical days for residents (78/89, 88%) and fellows (48/68, 71%). Conferences shifted to remote live format (57/78, 73%), with some canceled (15/78, 19%). Compared to pre-pandemic, resident diagnostic (75/78, 96% vs 26/78, 33%) (P < 0.001) and procedural (73/78, 94% vs 21/78, 27%) (P < 0.001) participation fell, as did fellow diagnostic (60/61, 98% vs 47/61, 77%) (P = 0.001) and procedural (60/61, 98% vs 43/61, 70%) (P < 0.001) participation. Most thought that the pandemic negatively influenced resident and fellow screening (64/77, 83% and 43/60, 72%, respectively), diagnostic (66/77, 86% and 37/60, 62%), and procedural (71/77, 92% and 37/61, 61%) education. However, a majority thought that decreased time on service (36/67, 54%) and patient contact (46/79, 58%) would not change residents' pursuit of a breast imaging fellowship. CONCLUSION: The pandemic has had a largely negative impact on breast imaging education, with reduction in exposure to all aspects of breast imaging. However, this may not affect career decisions.

Anxiety and Its Association With Screening Mammography.

Anxiety is often cited as a risk of screening mammography, and organizations such as the U.S. Preventive Services Task Force list anxiety as a screening-associated "harm" that should be mitigated. However, the level of mammography-related anxiety risk is difficult to assign clearly for myriad reasons, including the variability of individuals' baseline susceptibility to anxiety, the self-reported nature of subjective anxiety states, and the multiple sources of breast cancer screening-related anxiety. In addition, anxiety measures differ between studies and psychological responses to screening mammography vary across racial and ethnic groups. Nonetheless, breast radiology practices should acknowledge the existence of mammography-associated anxiety and consider strategies to decrease it. These strategies include immediate screening interpretations, patient education efforts, and relaxation techniques.

Screening Breast MRI and the Science of Premenopausal Background Parenchymal Enhancement.

The significance of background parenchymal enhancement (BPE) on screening and diagnostic breast MRI continues to be elucidated. Background parenchymal enhancement was initially deemed probably benign and followed or thought of as an artifact degrading the accuracy of breast cancer detection on breast MRI examinations. Subsequent research has focused on understanding the role of BPE regarding screening breast MRI. Today, there is growing evidence that a myriad of factors affect BPE, which in turn may influence patient outcomes. Additionally, BPE could represent an important risk factor for the future development of breast cancer. This article aims to describe the most up-to-date research on BPE as it relates to screening breast MRI in premenopausal women.

Adaptations of Breast Imaging Centers to the COVID-19 Pandemic: A Survey of California and Texas.

OBJECTIVE: To determine the early impact of the COVID-19 pandemic on breast imaging centers in California and Texas and compare regional differences. METHODS: An 11-item survey was emailed to American College of Radiology accredited breast imaging facilities in California and Texas in August 2020. A question subset addressed March-April government restrictions on elective services ("during the shutdown" and "after reopening"). Comparisons were made between states with chi-square and Fisher's tests, and timeframes with McNemar's and paired t-tests. RESULTS: There were 54 respondents (54/240, 23%, 26 California, 28 Texas). Imaging volumes fell during the shutdown and remained below pre-pandemic levels after reopening, with reduction in screening greatest (ultrasound 12% of baseline, mammography 13%, MRI 23%), followed by diagnostic MRI (43%), procedures (44%), and diagnostics (45%). California reported higher volumes during the shutdown (procedures, MRI) and after reopening (diagnostics, procedures, MRI) versus Texas (P = 0.001-0.02). Most screened patients (52/54, 96% symptoms and 42/54, 78% temperatures), and 100% (53/53) modified check-in and check-out. Reading rooms or physician work were altered for social distancing (31/54, 57%). Physician mask (45/48, 94%), gown (15/48, 31%), eyewear (22/48, 46%), and face shield (22/48, 46%) use during procedures increased after reopening versus pre-pandemic (P < 0.001-0.03). Physician (47/54, 87%) and staff (45/53, 85%) financial impacts were common, but none reported terminations. CONCLUSION: Breast imaging volumes during the early pandemic fell more severely in Texas than in California. Safety measures and financial impacts on physicians and staff were similar in both states.

Extramedullary Plasmacytoma of the breast in a patient with Multiple Myeloma.

Extramedullary plasmacytoma of the breast is rare. It is important to recognize the imaging findings and include it as a differential consideration in multiple myeloma patients with a breast mass. A 74-year-old woman undergoing chemotherapy for relapsed multiple myeloma presented with a palpable mass in her right breast. A screening mammogram four months prior was unremarkable. She underwent a diagnostic right mammogram which showed two well-circumscribed hyperdense masses. An ultrasound of the right breast showed mixed echogenic masses with indistinct margins and increased vascularity. Ultrasound guided biopsy confirmed the presence of an extramedullary plasmacytoma. A follow-up whole body PET/CT demonstrated an FDG-avid right breast mass with extensive osseous metastases.

Developmental Approaches to Faculty Development.

An academic career goes through developmental stages and faculty have different needs as they progress through these stages. Faculty development initiatives can target these developmental needs. Early career faculty develop their clinical and academic identities and benefit from orientation programs and mentorship. Mid-career faculty engage in role transitions, consolidating their careers, and focusing on productivity and generativity. They benefit from programs that provide new skills, including leadership skills. Advanced career faculty focus on professional-personal integration, contributing to a community, and changes in roles and power. They can benefit from mentorship, from peers locally and at a distance.

Conspicuity of suspicious breast lesions on contrast enhanced breast CT compared to digital breast tomosynthesis and mammography.

OBJECTIVE: Compare conspicuity of suspicious breast lesions on contrast-enhanced dedicated breast CT (CEbCT), tomosynthesis (DBT) and digital mammography (DM). METHODS: 100 females with BI-RADS 4/5 lesions underwent CEbCT and/or DBT prior to biopsy in this IRB approved, HIPAA compliant study. Two breast radiologists adjudicated lesion conspicuity scores (CS) for each modality independently. Data are shown as mean CS ±standard deviation. Two-sided t-test was used to determine significance between two modalities within each subgroup. Multiple comparisons were controlled by the false-discovery rate set to 5%. RESULTS: 50% of studied lesions were biopsy-confirmed malignancies. Malignant masses were more conspicuous on CEbCT than on DBT or DM (9.7 ±0.5, n = 25; 6.8 ± 3.1, n = 15; 6.7 ± 3.0, n = 27; p < 0.05). Malignant calcifications were equally conspicuous on all three modalities (CEbCT 8.7 ± 0.8, n = 18; DBT 8.5 ± 0.6, n = 15; DM 8.8 ± 0.7, n = 23; p = NS). Benign masses were equally conspicuous on CEbCT (6.6 ± 4.1, n = 22); DBT (6.4 ± 3.8, n = 17); DM (5.9 ± 3.6, n = 24; p = NS). Benign calcifications CS were similar between DBT (8.5 ± 1.0, n = 17) and DM (8.8 ± 0.8, n = 26; p = NS) but less conspicuous on CEbCT (4.0 ± 2.9, n = 25, p < 0.001). 55 females were imaged with all modalities. Results paralleled the entire cohort. 69%(n = 62) of females imaged by CEbCT had dense breasts. Benign/malignant lesion CSs in dense/non-dense categories were 4.8 ± 3.7, n = 33, vs 6.0 ± 3.9, n = 14, p = 0.35; 9.2 ± 0.9, n = 29 vs. 9.4 ± 0.7, n = 14; p = 0.29, respectively. CONCLUSION: Malignant masses are more conspicuous on CEbCT than DM or DBT. Malignant microcalcifications are equally conspicuous on all three modalities. Benign calcifications remain better visualized by DM and DBT than with CEbCT. We observed no differences in benign masses on all modalities. CS of both benign and malignant lesions were independent of breast density. ADVANCES IN KNOWLEDGE: CEbCT is a promising diagnostic imaging modality for suspicious breast lesions.

The Doctor-Patient Relationship With Artificial Intelligence.

OBJECTIVE: The doctor-patient relationship has been evolving from benevolent paternalism to a more patient-centered relationship in the modern era. Although artificial intelligence (AI) has the potential to improve nearly every aspect of health care, many physicians are skeptical about integrating AI into their current medical practice. The purpose of this article is to explore what AI means for the doctor-patient relationship and for breast imaging radiologists. CONCLUSION: The promise of AI is its potential to release physicians from tasks that are better performed by automation. AI may enhance our diagnostic accuracy to the point that we are able to refocus on the art of the doctor-patient relationship.

Radiologist-Patient Communication: Current Practices and Barriers to Communication in Breast Imaging.

PURPOSE: The aim of this study was to assess variability in radiologist-patient communication practices and barriers to communication among members of the Society of Breast Imaging (SBI). METHODS: A 36-item questionnaire developed by the SBI Patient Care and Delivery Task Force was distributed electronically to SBI members to evaluate patient communication, education, and screening practices. Data from 14 items investigating patient communication (eg, practices, comfort, barriers to communication) were analyzed and compared with demographic variables using χ2 or independent t tests as appropriate. RESULTS: Ninety-three percent of radiologists reported that they directly communicate abnormal results of diagnostic mammographic examinations that require biopsy and malignant or high-risk biopsy results that require surgery. Radiologists (66%) and technologists (57%) often provide normal or negative diagnostic mammographic results. Most respondents were completely comfortable discussing the need for additional imaging, recommending biopsy, and discussing biopsy results directly with patients, and 71% rated their communication skills as excellent. Radiologists who spend less time in breast imaging reported only average communication skills. The most frequent barriers to communication were that practices were not set up for direct communication (loss of revenue) and discomfort with angry patients. CONCLUSIONS: Although variation in breast imaging communication practices exists among radiologists and practice types, the majority of radiologists directly communicate the most distressing results to patients, such as those regarding abnormal diagnostic mammographic findings requiring biopsies and abnormal biopsy results leading to cancer diagnoses and surgery. The majority of radiologists are completely comfortable with these conversations, but all feel that enhancing communication with patients will lead to greater patient satisfaction.

Screening Guidelines and Supplemental Screening Tools: Assessment of the Adequacy of Patient-Provider Discussions.

PURPOSE: To assess breast imaging radiologists' perceptions of the adequacy of provider-patient discussions regarding the benefits and risks of screening mammography and supplemental screening in women with elevated risk and dense breasts. METHODS: A 36-item questionnaire developed by the Society of Breast Imaging Patient Care and Delivery Task Force was distributed electronically to Society of Breast Imaging members to evaluate patient communication, education, and screening practices. Data from the 11 items specifically pertaining to screening practices were analyzed. RESULTS: The response rate was 14% (275/1992). Seventy-four percent of survey respondents perceived provider-patient discussions regarding mammography screening guidelines as inadequate, and they agreed that provider-patient discussions regarding screening guidelines (82%) and supplemental screening for increased breast density (74%) should be standardized. Only 38% indicated that mammography screening guidelines are officially endorsed by their institution. Similarly, 37% reported that recommendations were up to the primary provider. Although most respondents include information about breast density in lay letters (73%) and radiology reports (89%), many feel that further patient education regarding breast density, supplemental screening, risk assessment, and screening guidelines should be performed by radiologists, and they are willing to provide additional patient education in these areas in practice. CONCLUSIONS: Survey respondents perceived current provider-patient discussions about the risks and benefits of breast cancer mammography screening and supplemental screening as inadequate and felt that standards should be developed. Respondents reported a willingness to take on patient education as part of their daily practice. These findings could inform future initiatives for radiologists to contribute to enhancing provider-patient education.

Impact of the California Breast Density Law on Screening Breast MR Utilization, Provider Ordering Practices, and Patient Demographics.

PURPOSE: To assess the impact of California's Breast Density Law (BDL) on MRI utilization and clinician ordering practices. MATERIALS AND METHODS: Our institutional review board approved this study that retrospectively compared the ordering pattern for screening breast MRI examinations in the 30-month period before and after the BDL was enacted. Examinations were subcategorized into those with breast density mentioned as an examination indication. Patients were classified into (1) high risk; (2) above average risk, defined but not quantified; and (3) undefined or average risk. χ2 test or Fisher's exact test was used to compare MRI utilization, use of breast density as an indication, patient demographics, and provider characteristics. RESULTS: Screening MRI examinations with breast density as the indication increased from 8.5% (32 of 376) to 21.1% (136 of 646, P < .0001) after BDL. When high-risk patients were excluded, the increase was from 8% to 17.2% (P < .0001). Patient demographics before and after BDL were, by race: white 71.8% versus 71.2%; Asian 6.4% versus 10.5%; black 3.7% versus 3.1%; American Indian 0.3% versus 1.4%; Native Hawaiian or Pacific Islander 1.6% versus 1.7%; by ethnicity: Hispanic or Latino 10.6% versus 7.9%. Before and after BDL, predominantly female providers (81.4% and 77.4%, P = not significant [NS]) and specialists (62.5% and 63.5%, P = NS) ordered the majority of breast MRI examinations compared with males (18.6% and 22.6%, P = NS). CONCLUSION: Screening breast MRI utilization for non-high-risk women more than doubled after the California BDL went into effect. BDL has had an impact on MRI utilization, and its clinical value for changing outcomes deserves further study.

A method to increase reproducibility in adult ventricular myocyte sizing and flow cytometry: Avoiding cell size bias in single cell preparations.

RATIONALE: Flow cytometry (FCM) of ventricular myocytes (VMs) is an emerging technology in adult cardiac research that is challenged by the wide variety of VM shapes and sizes. Cellular variability and cytometer flow cell size can affect cytometer performance. These two factors of variance limit assay validity and reproducibility across laboratories. Washing and filtering of ventricular cells in suspension are routinely done to prevent cell clumping and minimize data variability without the appropriate standardization. We hypothesize that washing and filtering arbitrarily biases towards sampling smaller VMs than what actually exist in the adult heart. OBJECTIVE: To determine the impact of washing and filtering on adult ventricular cells for cell sizing and FCM. METHODS AND RESULTS: Left ventricular cardiac cells in single-cell suspension were harvested from New Zealand White rabbits and fixed prior to analysis. Each ventricular sample was aliquoted before washing or filtering through a 40, 70, 100 or 200µm mesh. The outcomes of the study are VM volume by Coulter Multisizer and light-scatter signatures by FCM. Data are presented as mean±SD. Myocyte volumes without washing or filtering (NF) served as the "gold standard" within the sample and ranged from 11,017 to 46,926µm3. Filtering each animal sample through a 200µm mesh caused no variation in the post-filtration volume (1.01+0.01 fold vs. NF, n = 4 rabbits, p = 0.999) with an intra-assay coefficient of variation (%CV) of <5% for all 4 samples. Filtering each sample through a 40, 70 or 100µm mesh invariably reduced the post-filtration volume by 41±10%, 9.0±0.8% and 8.8±0.8% respectively (n = 4 rabbits, p<0.0001), and increased the %CV (18% to 1.3%). The high light-scatter signature by FCM, a simple parameter for the identification of ventricular myocytes, was measured after washing and filtering. Washing discarded VMs and filtering cells through a 40 or 100µm mesh reduced larger VM by 46% or 11% respectively (n = 6 from 2 rabbits, p<0.001). CONCLUSION: Washing and filtering VM suspensions through meshes 100µm or less biases myocyte volumes to smaller sizes, excludes larger cells, and increases VM variability. These findings indicate that validity and reproducibility across laboratories can be compromised unless cell preparation is standardized. We propose no wash prior to fixation and a 200µm mesh for filtrations to provide a reproducible standard for VM studies using FCM.

Can Radiologists Predict the Presence of Ductal Carcinoma In Situ and Invasive Breast Cancer?

OBJECTIVE: We hypothesize that radiologists' estimated percentage likelihood assessments for the presence of ductal carcinoma in situ (DCIS) and invasive cancer may predict histologic outcomes. MATERIALS AND METHODS: Two hundred fifty cases categorized as BI-RADS category 4 or 5 at four University of California Medical Centers were retrospectively reviewed by 10 academic radiologists with a range of 1-39 years in practice. Readers assigned BI-RADS category (1, 2, 3, 4a, 4b, 4c, or 5), estimated percentage likelihood of DCIS or invasive cancer (0-100%), and confidence rating (1 = low, 5 = high) after reviewing screening and diagnostic mammograms and ultrasound images. ROC curves were generated. RESULTS: Sixty-two percent (156/250) of lesions were benign and 38% (94/250) were malignant. There were 26 (10%) DCIS, 20 (8%) invasive cancers, and 48 (19%) cases of DCIS and invasive cancer. AUC values were 0.830-0.907 for invasive cancer and 0.731-0.837 for DCIS alone. Sensitivity of 82% (56/68), specificity of 84% (153/182), positive predictive value (PPV) of 66% (56/85), negative predictive value (NPV) of 93% (153/165), and accuracy of 84% ([56 + 153]/250) were calculated using an estimated percentage likelihood of 20% or higher as the prediction threshold for invasive cancer for the radiologist with the highest AUC (0.907; 95% CI, 0.864-0.951). Every 20% increase in the estimated percentage likelihood of invasive cancer increased the odds of invasive cancer by approximately two times (odds ratio, 2.4). For DCIS, using a threshold of 40% or higher, sensitivity of 81% (21/26), specificity of 79% (178/224), PPV of 31% (21/67), NPV of 97% (178/183), and accuracy of 80% ([21 + 178]/250) were calculated. Similarly, these values were calculated at thresholds of 2% or higher (BI-RADS category 4) and 95% or higher (BI-RADS category 5) to predict the presence of malignancy. CONCLUSION: Using likelihood estimates, radiologists may predict the presence of invasive cancer with fairly high accuracy. Radiologist-assigned estimated percentage likelihood can predict the presence of DCIS, albeit with lower accuracy than that for invasive cancer.

Inter-reader Variability in the Use of BI-RADS Descriptors for Suspicious Findings on Diagnostic Mammography: A Multi-institution Study of 10 Academic Radiologists.

RATIONALE AND OBJECTIVES: The study aimed to determine the inter-observer agreement among academic breast radiologists when using the Breast Imaging Reporting and Data System (BI-RADS) lesion descriptors for suspicious findings on diagnostic mammography. MATERIALS AND METHODS: Ten experienced academic breast radiologists across five medical centers independently reviewed 250 de-identified diagnostic mammographic cases that were previously assessed as BI-RADS 4 or 5 with subsequent pathologic diagnosis by percutaneous or surgical biopsy. Each radiologist assessed the presence of the following suspicious mammographic findings: mass, asymmetry (one view), focal asymmetry (two views), architectural distortion, and calcifications. For any identified calcifications, the radiologist also described the morphology and distribution. Inter-observer agreement was determined with Fleiss kappa statistic. Agreement was also calculated by years of experience. RESULTS: Of the 250 lesions, 156 (62%) were benign and 94 (38%) were malignant. Agreement among the 10 readers was strongest for recognizing the presence of calcifications (k = 0.82). There was substantial agreement among the readers for the identification of a mass (k = 0.67), whereas agreement was fair for the presence of a focal asymmetry (k = 0.21) or architectural distortion (k = 0.28). Agreement for asymmetries (one view) was slight (k = 0.09). Among the categories of calcification morphology and distribution, reader agreement was moderate (k = 0.51 and k = 0.60, respectively). Readers with more experience (10 or more years in clinical practice) did not demonstrate higher levels of agreement compared to those with less experience. CONCLUSIONS: Strength of agreement varies widely for different types of mammographic findings, even among dedicated academic breast radiologists. More subtle findings such as asymmetries and architectural distortion demonstrated the weakest agreement. Studies that seek to evaluate the predictive value of certain mammographic features for malignancy should take into consideration the inherent interpretive variability for these findings.

Temporal subtraction contrast-enhanced dedicated breast CT.

The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0-16%), NCC (0-6%), NMI (0-13%) and TRE (0-34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was implemented using a parallel processing architecture resulting in rapid execution time for the iterative segmentation and intensity-adaptive registration techniques. Characterization of contrast-enhanced lesions is improved using temporal subtraction contrast-enhanced dedicated breast CT. Adaptation of Demons registration forces as a function of contrast-enhancement levels provided a means to accurately align breast tissue in pre- and post-contrast image acquisitions, improving subtraction results. Spatial subtraction of the aligned images yields useful diagnostic information with respect to enhanced lesion morphology and uptake.