Variability of Postsurgical Imaging Surveillance of Breast Cancer Patients: A Nationwide Survey Study.

OBJECTIVE: Because of observed clinical variance and the discretion of referring physicians and radiologists in patient follow-up, the purpose of this study was to conduct a survey to explore whether broad discrepancy exists in imaging protocols used for postsurgical surveillance. SUBJECTS AND METHODS: An online survey was created to assess radiologists' use of diagnostic versus screening mammography for women with a personal history of breast cancer and determine whether the choice of protocol was associated with practice characteristics (setting, region, and reader type). RESULTS: Of 8170 surveys sent, 849 (10%) completed responses were returned. Seventy-nine percent of respondents recommended initial diagnostic mammography after lumpectomy (65% at 6 months, 14% at 12 months); 49% recommended diagnostic surveillance for up to 2 years before a return to screening mammography; and 33% continued diagnostic surveillance for 2-5 years before returning to screening. For imaging after mastectomy, 57% of respondents recommended diagnostic mammography of the unaffected breast. Among the 57%, however, 37% recommended diagnostic screening for only the first postmastectomy follow-up evaluation, and the other 20% permanently designated patients for diagnostic mammography after mastectomy. CONCLUSION: The optimal surveillance mammography regimen must be better defined. This preliminary study showed variability in diagnostic versus screening surveillance mammography for women with a history of breast cancer. Future studies should evaluate why these variations occur and how to standardize recommendations to tailor personalized imaging.

Can Breast Compression Be Reduced in Digital Mammography and Breast Tomosynthesis?

OBJECTIVE: The objective of this study was to investigate the impact of decreasing breast compression during digital mammography and breast tomosynthesis (DBT) on perceived pain and image quality. MATERIALS AND METHODS: In this two-part study, two groups of women with prior mammograms were recruited. In part 1, subjects were positioned for craniocaudal (CC) and mediolateral oblique (MLO) views, and four levels of compression force were applied to evaluate changes in breast thickness, perceived pain, and relative tissue coverage. No imaging was performed. In part 2, two MLO DBT images of one breast of each patient were acquired at standard and reduced compression. Blurring artifacts and tissue coverage were judged by three breast imaging radiologists, and compression force, breast thickness, relative tissue coverage, and perceived pain were recorded. RESULTS: Only the first reduction in force was feasible because further reduction resulted in inadequate breast immobilization. Mean force reductions of 48% and 47% for the CC and MLO views, respectively, resulted in a significantly reduced perceived pain level, whereas the thickness of the compressed breast increased by 0.02 cm (CC view) and 0.09 (MLO view, part 1 of the study) and 0.38 cm (MLO view, part 2 of the study), respectively, with no change in tissue coverage or increase in motion blurring. CONCLUSION: Mammography and DBT acquisitions may be possible using half of the compression force used currently, with a significant and substantial reduction in perceived pain with no clinically significant change in breast thickness and tissue coverage.

X-ray scatter correction method for dedicated breast computed tomography: improvements and initial patient testing.

A previously proposed x-ray scatter correction method for dedicated breast computed tomography was further developed and implemented so as to allow for initial patient testing. The method involves the acquisition of a complete second set of breast CT projections covering 360° with a perforated tungsten plate in the path of the x-ray beam. To make patient testing feasible, a wirelessly controlled electronic positioner for the tungsten plate was designed and added to a breast CT system. Other improvements to the algorithm were implemented, including automated exclusion of non-valid primary estimate points and the use of a different approximation method to estimate the full scatter signal. To evaluate the effectiveness of the algorithm, evaluation of the resulting image quality was performed with a breast phantom and with nine patient images. The improvements in the algorithm resulted in the avoidance of introduction of artifacts, especially at the object borders, which was an issue in the previous implementation in some cases. Both contrast, in terms of signal difference and signal difference-to-noise ratio were improved with the proposed method, as opposed to with the correction algorithm incorporated in the system, which does not recover contrast. Patient image evaluation also showed enhanced contrast, better cupping correction, and more consistent voxel values for the different tissues. The algorithm also reduces artifacts present in reconstructions of non-regularly shaped breasts. With the implemented hardware and software improvements, the proposed method can be reliably used during patient breast CT imaging, resulting in improvement of image quality, no introduction of artifacts, and in some cases reduction of artifacts already present. The impact of the algorithm on actual clinical performance for detection, diagnosis and other clinical tasks in breast imaging remains to be evaluated.

Does Preoperative MRI Workup Affect Mastectomy Rates and/or Re-excision Rates in Patients with Newly Diagnosed Breast Carcinoma? A Retrospective Review.

The purpose of this study is to determine whether including breast magnetic resonance imaging (MRI) in the preoperative workup of patients with known breast cancer has an impact on mastectomy and/or re-excision rates. This is an Institutional Review Board approved HIPAA compliant retrospective study reviewing the impact MRI has on mastectomy and re-excision rates in patients with newly diagnosed breast cancer. Our study compares two groups: (i) 154 patients who did not receive preoperative MRIs and served as a control group and (ii) 96 patients who received preoperative breast MRIs. Patient race and age between the two populations were not statistically different. The difference in mastectomy rates between the two populations was 10.7%; although not statistically different, the p value of 0.10 suggests a trend toward significance. The re-excision rates between the two populations, however, were significantly different (p < 0.001), with women in the control group having a higher re-excision rate than those in the study group. The difference between involved and clear margins was significant as well (p = 0.002), with patients undergoing preoperative MRI more likely to have negative margins. Preoperative breast MRI significantly decreases the likelihood of involved margins as well as the need for surgical re-excision. Preoperative breast MRI does not result in a statistically significant difference in mastectomy rates, although further investigation is required to determine whether there is a trend towards statistical significance.

X-ray scatter correction in breast tomosynthesis with a precomputed scatter map library.

PURPOSE: To develop and evaluate the impact on lesion conspicuity of a software-based x-ray scatter correction algorithm for digital breast tomosynthesis (DBT) imaging into which a precomputed library of x-ray scatter maps is incorporated. METHODS: A previously developed model of compressed breast shapes undergoing mammography based on principal component analysis (PCA) was used to assemble 540 simulated breast volumes, of different shapes and sizes, undergoing DBT. A Monte Carlo (MC) simulation was used to generate the cranio-caudal (CC) view DBT x-ray scatter maps of these volumes, which were then assembled into a library. This library was incorporated into a previously developed software-based x-ray scatter correction, and the performance of this improved algorithm was evaluated with an observer study of 40 patient cases previously classified as BI-RADS® 4 or 5, evenly divided between mass and microcalcification cases. Observers were presented with both the original images and the scatter corrected (SC) images side by side and asked to indicate their preference, on a scale from -5 to +5, in terms of lesion conspicuity and quality of diagnostic features. Scores were normalized such that a negative score indicates a preference for the original images, and a positive score indicates a preference for the SC images. RESULTS: The scatter map library removes the time-intensive MC simulation from the application of the scatter correction algorithm. While only one in four observers preferred the SC DBT images as a whole (combined mean score = 0.169 ± 0.37, p > 0.39), all observers exhibited a preference for the SC images when the lesion examined was a mass (1.06 ± 0.45, p < 0.0001). When the lesion examined consisted of microcalcification clusters, the observers exhibited a preference for the uncorrected images (-0.725 ± 0.51, p < 0.009). CONCLUSIONS: The incorporation of the x-ray scatter map library into the scatter correction algorithm improves the efficiency of the algorithm. The observer study presented here is also the first test of the scatter correction algorithm with patient images and human observers, and demonstrates its potential to improve the clinical performance of DBT.

Stereoscopic digital mammography: improved specificity and reduced rate of recall in a prospective clinical trial.

PURPOSE: To compare stereoscopic digital mammography (DM) with standard DM for the rate of patient recall and the detection of cancer in a screening population at elevated risk for breast cancer. MATERIALS AND METHODS: Starting in September 2004 and ending in December 2007, this prospective HIPAA-compliant, institutional review board-approved screening trial, with written informed consent, recruited female patients at elevated risk for breast cancer (eg, personal history of breast cancer or breast cancer in a close relative). A total of 1298 examinations from 779 patients (mean age, 58.6 years; range, 32-91 years) comprised the analyzable data set. A paired study design was used, with each enrolled patient serving as her own control. Patients underwent both DM and stereoscopic DM examinations in a single visit, findings of which were interpreted independently by two experienced radiologists, each using a Breast Imaging Reporting and Data System (BI-RADS) assessment (BI-RADS category 0, 1, or 2). All patients determined to have one or more findings with either or both modalities were recalled for standard diagnostic evaluation. The results of 1-year follow-up or biopsy were used to determine case truth. RESULTS: Compared with DM, stereoscopic DM showed significantly higher specificity (91.2% [1167 of 1279] vs 87.8% [1123 of 1279]; P = .0024) and accuracy (90.9% [1180 of 1298] vs 87.4% [1135 of 1298]; P = .0023) for detection of cancer. Sensitivity for detection of cancer was not significantly different for stereoscopic DM (68.4% [13 of 19]) compared with DM (63.2% [12 of 19], P .99). The recall rate for stereoscopic DM was 9.6% (125 of 1298) and that for DM was 12.9% (168 of 1298) (P = .0018). CONCLUSION: Compared with DM, stereoscopic DM significantly improved specificity for detection of cancer, while maintaining comparable sensitivity. The recall rate was significantly reduced with stereoscopic DM compared with DM. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120382/-/DC1.

Evaluating imaging and computer-aided detection and diagnosis devices at the FDA.

This report summarizes the Joint FDA-MIPS Workshop on Methods for the Evaluation of Imaging and Computer-Assist Devices. The purpose of the workshop was to gather information on the current state of the science and facilitate consensus development on statistical methods and study designs for the evaluation of imaging devices to support US Food and Drug Administration submissions. Additionally, participants expected to identify gaps in knowledge and unmet needs that should be addressed in future research. This summary is intended to document the topics that were discussed at the meeting and disseminate the lessons that have been learned through past studies of imaging and computer-aided detection and diagnosis device performance.

The risk for medial arterial calcification in CKD.

BACKGROUND AND OBJECTIVES: CKD is a risk factor for medial artery calcification, but the CKD stage at which this risk begins is unknown. Because breast arterial calcification (BAC) is a marker of generalized medial arterial calcification, mammography was used to detect medial arterial calcification in women with different CKD stages. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This was a retrospective, cross-sectional study of women with and without CKD matched for age and diabetes and identified from mammograms obtained in 2006-2011. BAC was scored as present or absent per visual inspection. RESULTS: A total of 146 women with stage 3 CKD and 54 with stage 4/5 CKD were identified. An additional 21 patients with ESRD were identified and added to a previous cohort of 71 patients. Mean age was 64 years for CKD 3, 63 for CKD 4, and 59 for ESRD. Half of each group had diabetes. Compared with controls, the odds ratios for BAC were 1.44 in CKD 3 (95% confidence interval [CI], 0.82-2.53), 2.69 in CKD 4 (95% CI, 1.14-6.33), and 7.19 in ESRD (95% CI, 3.77-13.7) and did not differ with diabetic status or race. In a multivariable logistic model, age (P<0.001) and estimated GFR (P=0.005) were independent predictors of BAC. The odds ratio for BAC increased 4% for each milliliter per minute per 1.73 m(2) decrease in estimated GFR. The prevalence of BAC in CKD was increased in each decade of age over 49 years. CONCLUSIONS: CKD is an independent risk factor for medial arterial calcification.

On the frontline of screening for breast cancer.

The mainstay of screening for breast cancer is the mammogram. There are several randomized control trials that demonstrate a significant decrease in breast cancer mortality when compared to women without screening mammography included in their care. Digital mammography has improved detection in the dense breast. With the introduction of digital mammography, other novel techniques such as stereo digital mammography (SDM) and tomosynthesis can reduce recall significantly without a negative effect on cancer detection. Magnetic resonance imaging (MRI) and ultrasound added to mammography can improve cancer detection for high-risk women but can have false positive consequences.

Breast arterial calcification: a marker of medial vascular calcification in chronic kidney disease.

BACKGROUND AND OBJECTIVES: Because previous studies have not distinguished between intimal (atherosclerotic) and medial vascular calcification, the prevalence and clinical significance of either condition in chronic or end-stage kidney disease (CKD or ESKD) are unknown. We hypothesized that breast arterial calcification (BAC) is exclusively medial and that mammography can serve as a useful marker of generalized medial calcification in CKD and ESKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Arterial calcification was identified histologically in breast tissue or visually in mammograms and radiographs of extremities from patients with CKD or ESKD. RESULTS: Medial calcification but no intimal calcification was present in all 16 specimens from patients with CKD or ESKD. In 71 women with ESKD, BAC was present on mammograms in 63% compared with 17% in women without renal insufficiency matched for age, race, and diabetes (P<0.001). Age and ESKD duration were significant, independent predictors of BAC. BAC was also present in 36% of mammograms from the same patients performed 5.5±0.7 years before the onset of ESKD (P<0.05 versus control) but in only 14% of patients with stage 3 CKD. Comparison of mammograms and extremity radiographs revealed that BAC was present in over 90% of patients with peripheral arterial calcification (PAC), and PAC was observed in less than 6% of patients without BAC. CONCLUSIONS: BAC is a specific and useful marker of medial vascular calcification in CKD, and its prevalence is markedly increased in ESKD and advanced CKD.

ACR Appropriateness Criteria® on nonpalpable mammographic findings (excluding calcifications).

Screening mammography can detect breast cancer before it becomes clinically apparent. However, the screening process identifies many false-positive findings for each cancer eventually confirmed. Additional tools are available to help differentiate spurious findings from real ones and to help determine when tissue sampling is required, when short-term follow-up will suffice, or whether the finding can be dismissed as benign. These tools include additional diagnostic mammographic views, breast ultrasound, breast MRI, and, when histologic evaluation is required, percutaneous biopsy. The imaging evaluation of a finding detected at screening mammography proceeds most efficiently, cost-effectively, and with minimization of radiation dose when approached in an evidence-based manner. The appropriateness of the above-referenced tools is presented here as they apply to a variety of findings often encountered on screening mammography; an algorithmic approach to workup of these potential scenarios is also included. The recommendations put forth represent a compilation of evidence-based data and expert opinion of the ACR Appropriateness Criteria(®) Expert Panel on Breast Imaging.

Imaging for the diagnosis and management of ductal carcinoma in situ.

Diagnosis of ductal carcinoma in situ (DCIS) has increased dramatically in parallel with the increased use of screening mammography. There are specific mammographic findings, most associated with shapes (amorphous, fine and coarse pleomorphic, and fine linear) and distributions (linear and segmental) of calcifications that permit a reasonable sensitivity for detection of DCIS without an unreasonable decrease in specificity, especially in view of the dramatic decrease in breast cancer mortality associated with early detection. While some DCIS may never progress to invasive disease, at this time, we cannot make that separation. This should be an active area for research.

Dosimetric characterization of a dedicated breast computed tomography clinical prototype.

PURPOSE: To investigate the glandular dose magnitudes and characteristics resulting from image acquisition using a dedicated breast computed tomography (BCT) clinical prototype imaging system. METHODS: The x-ray spectrum and output characteristics of a BCT clinical prototype (Koning Corporation, West Henrietta, NY) were determined using empirical measurements, breast phantoms, and an established spectrum model. The geometry of the BCT system was replicated in a Monte Carlo-based computer simulation using the GEANT4 toolkit and was validated by comparing the simulated results for exposure distribution in a standard 16 cm CT head phantom with those empirically determined using a 10 cm CT pencil ionization chamber and dosimeter. The computer simulation was further validated by replicating the results of a previous BCT dosimetry study. Upon validation, the computer simulation was modified to include breasts of varying sizes and homogeneous compositions spanning those encountered clinically, and the normalized mean glandular dose resulting from BCT was determined. Using the system's measured exposure output determined automatically for breasts of different size and density, the mean glandular dose for these breasts was computed and compared to the glandular dose resulting from mammography. Finally, additional Monte Carlo simulations were performed to study how the glandular dose values vary within the breast tissue during acquisition with both this BCT prototype and a typical craniocaudal (CC) mammographic acquisition. RESULTS: This BCT prototype uses an x-ray spectrum with a first half-value layer of 1.39 mm Al and a mean x-ray energy of 30.3 keV. The normalized mean glandular dose for breasts of varying size and composition during BCT acquisition with this system ranges from 0.278 to 0.582 mGy/mGy air kerma with the reference air kerma measured in air at the center of rotation. Using the measured exposure outputs for the tube currents automatically selected by the system for the breasts of different sizes and densities, the mean glandular dose for a BCT acquisition with this prototype system varies from 5.6 to 17.5 mGy, with the value for a breast of mean size and composition being 17.06 mGy. The glandular dose throughout the breast tissue of this mean breast varies by up to +/- 50% of the mean value. During a typical CC view mammographic acquisition of an equivalent mean breast, which typically results in a mean glandular dose of 2.0-2.5 mGy, the glandular dose throughout the breast tissue varies from approximately 15% to approximately 400% of the mean value. CONCLUSIONS: Acquisition of a BCT image with the automated tube output settings for a mean breast with the Koning Corp. clinical prototype results in mean glandular dose values approximately equivalent to three to five two-view mammographic examinations for a similar breast. For all breast sizes and compositions studied, this glandular dose ratio between acquisition with this BCT prototype and two-view mammography ranges from 1.4 to 7.2. In mammography, portions of the mean-sized breast receive a considerably higher dose than the mean value for the whole breast. However, only a small portion of a breast undergoing mammography would receive a glandular dose similar to that from BCT.

Dedicated breast computed tomography: the optimal cross-sectional imaging solution?

Dedicated breast computed tomography (DBCT) is a burgeoning technology that has many advantages over current breast-imaging systems. Three-dimensional visualization of the breast mitigates the limiting effects of superimposition noted with mammography. Postprocessing capabilities will allow application of advanced technologies, such as creation of maximum-intensity projection and subtraction images, and the use of both computer-aided detection and possible computer-aided diagnosis algorithms. Excellent morphologic detail and soft tissue contrast can be achieved, due in part to the isotropic image data that DBCT produces. The expected cost should be more reasonable than magnetic resonance imaging. At present, because the breast is not compressed, patients find it more comfortable than mammography. Physiologic information can be obtained when intravenous contrast material is used and/or when DBCT is combined with single photon emission-computed tomography or positron emission tomography. DBCT provides an excellent platform for multimodality systems including integration with interventional and therapeutic procedures. With a slightly altered design, the DBCT platform may also be useful for external-beam radiation with image guidance.