Improvement in mammography interpretation skills in a community radiology practice after dedicated teaching courses: 2-year medical audit of 38,633 cases

Auditing Abbreviated Breast MR Imaging: Clinical Considerations and Implications

Abbreviated breast MR (AB-MR) imaging is a relatively new breast imaging tool, which maintains diagnostic accuracy while reducing image times compared with full-protocol breast MR (FP-MR) imaging. Breast imaging audits involve calculating individual and organizational metrics, which can be compared with established benchmarks, providing a standard against which performance can be measured. Unlike FP-MR imaging, there are no established benchmarks for AB-MR imaging but studies demonstrate comparable performance for cancer detection rate, positive predictive value 3, sensitivity, and specificity with T2. We review the basics of performing an audit, including strategies to implement if benchmarks are not being met.

Effect of a dedicated PI-QUAL curriculum on the assessment of prostate MRI quality

PURPOSE

The Prostate Imaging Quality (PI-QUAL) score is a metric to evaluate the diagnostic quality of multiparametric magnetic resonance imaging (MRI) of the prostate. This study evaluated the impact of a prostate MRI quality training lecture on the participant's ability to assess prostate MRI image quality.

METHODS

Eighteen in-training-radiologists of varying experience in reviewing diagnostic prostate MRI assessed the image quality of ten examinations. Then, they attended a dedicated lecture on MRI quality assessment using the PI-QUAL score. After the lecture, the same participants evaluated the image quality of a new set of ten scans applying the PI-QUAL score. Results were assessed using receiver operating characteristic (ROC) analysis. The reference standard was the PI-QUAL score assessed by a fellowship trained abdominal radiologist with experience in reading prostate MRI.

RESULTS

There was a significant improvement in the average area under the curve (AUC) for assessment of prostate MRI image quality from baseline (0.82; [0.576 - 0.888]) to post teaching (1.0; [0.954-1]), with an improvement of 0.18 (p < 0.03). When ROC curves were computed for different cohorts stratified based on year of training, difference ranged from 0.48 for second year residents to 0.32 for fourth year residents (p < 0.001-0.01). For abdominal imaging fellows, the pre-teaching AUC was 0.9 [0.557-1] and post teaching AUC was 1 [0.957-1], a difference of 0.1 (p = 0.20).

CONCLUSIONS

A dedicated lecture on PI-QUAL improved the ability of radiologists-in-training to assess prostate MRI image quality, with variable impact depending on year of training.

Promoting the use of the PI-QUAL score for prostate MRI quality: results from the ESOR Nicholas Gourtsoyiannis teaching fellowship

OBJECTIVES

The Prostate Imaging Quality (PI-QUAL) score is a new metric to evaluate the diagnostic quality of multiparametric magnetic resonance imaging (MRI) of the prostate. This study assesses the impact of an intervention, namely a prostate MRI quality training lecture, on the participant's ability to apply PI-QUAL.

METHODS

Sixteen participants (radiologists, urologists, physicists, and computer scientists) of varying experience in reviewing diagnostic prostate MRI all assessed the image quality of ten examinations from different vendors and machines. Then, they attended a dedicated lecture followed by a hands-on workshop on MRI quality assessment using the PI-QUAL score. Five scans assessed by the participants were evaluated in the workshop using the PI-QUAL score for teaching purposes. After the course, the same participants evaluated the image quality of a new set of ten scans applying the PI-QUAL score. Results were assessed using receiver operating characteristic analysis. The reference standard was the PI-QUAL score assessed by one of the developers of PI-QUAL.

RESULTS

There was a significant improvement in average area under the curve for the evaluation of image quality from baseline (0.59 [95 % confidence intervals: 0.50-0.66]) to post-teaching (0.96 [0.92-0.98]), an improvement of 0.37 [0.21-0.41] (p < 0.001).

CONCLUSIONS

A teaching course (dedicated lecture + hands-on workshop) on PI-QUAL significantly improved the application of this scoring system to assess the quality of prostate MRI examinations.

KEY POINTS

• A significant improvement in the application of PI-QUAL for the assessment of prostate MR image quality was observed after an educational intervention. • Appropriate training on image quality can be delivered to those involved in the acquisition and interpretation of prostate MRI. • Further investigation will be needed to understand the impact on improving the acquisition of high-quality diagnostic prostate MR examinations.

Idiosyncratic biases in the perception of medical images

Introduction

Radiologists routinely make life-altering decisions. Optimizing these decisions has been an important goal for many years and has prompted a great deal of research on the basic perceptual mechanisms that underlie radiologists' decisions. Previous studies have found that there are substantial individual differences in radiologists' diagnostic performance (e.g., sensitivity) due to experience, training, or search strategies. In addition to variations in sensitivity, however, another possibility is that radiologists might have perceptual biases-systematic misperceptions of visual stimuli. Although a great deal of research has investigated radiologist sensitivity, very little has explored the presence of perceptual biases or the individual differences in these.

Methods

Here, we test whether radiologists' have perceptual biases using controlled artificial and Generative Adversarial Networks-generated realistic medical images. In Experiment 1, observers adjusted the appearance of simulated tumors to match the previously shown targets. In Experiment 2, observers were shown with a mix of real and GAN-generated CT lesion images and they rated the realness of each image.

Results

We show that every tested individual radiologist was characterized by unique and systematic perceptual biases; these perceptual biases cannot be simply explained by attentional differences, and they can be observed in different imaging modalities and task settings, suggesting that idiosyncratic biases in medical image perception may widely exist.

Discussion

Characterizing and understanding these biases could be important for many practical settings such as training, pairing readers, and career selection for radiologists. These results may have consequential implications for many other fields as well, where individual observers are the linchpins for life-altering perceptual decisions.

Using the Medical Audit to Improve Practice Performance

Feedback to physicians on their clinical performance is critical to continuous learning and maintenance of skills as well as maintaining patient safety. However, it is fraught with challenges around both implementation and acceptance. Additionally, rewarding of performance improvement is not often done, putting into question the efficacy of the process. Physician audit and feedback have been studied extensively and shown to be beneficial in many fields of medicine. Documenting physician performance and sharing individual and group data have been positively linked to changing physician behavior, ultimately leading to improved patient outcomes. Although casual review of one's own performance is often the easiest approach, it is frequently over- or underestimated by self-evaluation. Objective measures are therefore important to provide concrete data on which physicians can act. A fundamental question remains in mammography: Is reporting the information to the physician and accreditation bodies enough, or should there be consequences for the radiologist and/or facility if there is outlier behavior?

Promoting the use of the PRECISE score for prostate MRI during active surveillance: results from the ESOR Nicholas Gourtsoyiannis teaching fellowship

Objectives

The PRECISE criteria for serial multiparametric magnetic resonance imaging (MRI) of the prostate during active surveillance recommend the use of a dedicated scoring system (PRECISE score) to assess the likelihood of clinically significant radiological change. This pilot study assesses the effect of an interactive teaching course on prostate MRI during active surveillance in assessing radiological change in serial imaging.

Methods

Eleven radiology fellows and registrars with different experience in prostate MRI reading participated in a dedicated teaching course where they initially evaluated radiological change (based on their previous training in prostate MRI reading) independently in fifteen patients on active surveillance (baseline and follow-up scan), and then attended a lecture on the PRECISE score. The initial scans were reviewed for teaching purposes and afterwards the participants re-assessed the degree of radiological change in a new set of images (from fifteen different patients) applying the PRECISE score. Receiver operating characteristic analysis was performed. Confirmatory biopsies and PRECISE scores given in consensus by two radiologists (involved in the original draft of the PRECISE score) were the reference standard.

Results

There was a significant improvement in the average area under the curve (AUC) for the assessment of radiological change from baseline (AUC: 0.60 [Confidence Intervals: 0.51–0.69] to post-teaching (AUC: 0.77 [0.70–0.84]). This was an improvement of 0.17 [0.016–0.28] (p = 0.004).

Conclusions

A dedicated teaching course on the use of the PRECISE score improves the accuracy in the assessment of radiological change in serial MRI of the prostate.

Transitioning to Practice: Getting up to Speed in Efficiency and Accuracy

The transition from trainee to breast radiologist is challenging. The many new responsibilities that breast radiologists acquire while establishing themselves as clinicians may increase stress and anxiety. Taking inventory of existing knowledge and skills and addressing deficits toward the end of one's training can be beneficial. New breast radiologists should expect to be slower and gain proficiency in the first several years out of training. Having realistic expectations for oneself with respect to screening mammography interpretation and following up on the subsequent diagnostic imaging workup of screening callback examinations can increase competence and confidence. Familiarity with the available literature to guide management in the diagnostic setting can increase efficiency. Planning ahead for localizations and biopsies also allows for efficiency while alleviating anxiety. Ultimately, adapting to a new work environment using a collaborative approach with primary healthcare providers, pathologists, and surgeons while remembering to have mentors within and beyond the field of radiology allows for a more successful transition.

Improving radiologist's ability in identifying particular abnormal lesions on mammograms through training test set with immediate feedback

It has been shown that there are differences in diagnostic accuracy of cancer detection on mammograms, from below 50% in developing countries to over 80% in developed world. One previous study reported that radiologists from a population in Asia displayed a low mammographic cancer detection of 48% compared with over 80% in developed countries, and more importantly, that most lesions missed by these radiologists were spiculated masses or stellate lesions. The aim of this study was to explore the performance of radiologists after undertaking a training test set which had been designed to improve the capability in detecting a specific type of cancers on mammograms. Twenty-five radiologists read two sets of 60 mammograms in a standardized mammogram reading room. The first test set focused on stellate or spiculated masses. When radiologists completed the first set, the system displayed immediate feedback to the readers comparing their performances in each case with the truth of cancer cases and cancer types so that the readers could identify individual-based errors. Later radiologists were asked to read the second set of mammograms which contained different types of cancers including stellate/spiculated masses, asymmetric density, calcification, discrete mass and architectural distortion. Case sensitivity, lesion sensitivity, specificity, receiver operating characteristics (ROC) and Jackknife alternative free-response receiver operating characteristics (JAFROC) were calculated for each participant and their diagnostic accuracy was compared between two sessions. Results showed significant improvement among radiologists in case sensitivity (+ 11.4%; P < 0.05), lesion sensitivity (+ 18.7%; P < 0.01) and JAFROC (+ 11%; P < 0.01) in the second set compared with the first set. The increase in diagnostic accuracy was also recorded in the detection of stellate/spiculated mass (+ 20.6%; P < 0.05). This indicated that the performance of radiologists in detecting malignant lesions on mammograms can be improved if an appropriate training intervention is applied after the readers' weakness and strength are identified.

Errors in Breast Imaging: How to Reduce Errors and Promote a Safety Environment

Medical errors have a significant impact on patient care, worker safety, and health care finances. Breast imaging has the most common cause of organ-related misdiagnosis subject to malpractice suits. In order to effectively develop strategies to prevent errors, breast imaging radiologists must first understand the underlying causes of the errors that occur in the breast imaging setting. Errors in breast imaging can be related to errors in interpretation, improper workup of imaging findings, procedural errors, or errors in communication to the patient or other medical staff. The Yorkshire contributory factors framework was developed to identify factors that contribute to the errors in a hospital setting and can be adapted for use in the breast imaging setting. Within this framework, active failures refer to errors that directly affect the patient. Active errors include slips (including biases), lapses, and mistakes. The framework describes how active errors often result from factors that occur uphill from these active errors at different levels within the system. Once error causes are understood, there are concrete strategies and tools that breast imaging radiologists can implement to decrease adverse events, reduce medical errors, and promote a safety environment in the breast imaging clinic. Error mitigation tools can be summarized using the acronym SAFE, which includes support the team, ask questions, focus on a task, and effectively communicate/ensure equipment optimization/safe environment. Knowledge of errors commonly seen in a breast imaging clinic represent an opportunity for constructive changes and, ultimately, improved health care delivery.

Missed Breast Cancer: Effects of Subconscious Bias and Lesion Characteristics

Medical errors are a substantial cause of morbidity and mortality and the third leading cause of death in the United States. Errors resulting in missed breast cancer are the most common reason for medical malpractice lawsuits against all physicians. Missed breast cancers are breast malignancies that are detectable at retrospective review of a previously obtained mammogram that was prospectively reported as showing negative, benign, or probably benign findings. Investigators in prior studies have found that up to 35% of both interval cancers and screen-detected cancers could be classified as missed. As such, in conjunction with having awareness of the most common misleading appearances of breast cancer, it is important to understand the cognitive processes and unconscious biases that can impact image interpretation, thereby helping to decrease the number of missed breast cancers. The various cognitive processes that lead to unconscious bias in breast imaging, such as satisfaction of search, inattention blindness, hindsight, anchoring, premature closing, and satisfaction of reporting, are outlined in this pictorial review of missed breast cancers. In addition, strategies for reducing the rates of these missed cancers are highlighted. The most commonly missed and misinterpreted lesions, including stable lesions, benign-appearing masses, one-view findings, developing asymmetries, subtle calcifications, and architectural distortion, also are reviewed. This information will help illustrate why and how breast cancers are missed and aid in the development of appropriate minimization strategies in breast imaging. ^©RSNA, 2020.

Investigation of spectral performance for single-scan contrast-enhanced breast CT using photon-counting technology: A phantom study

PURPOSE

Contrast-enhanced imaging of the breast is frequently used in breast MRI and has recently become more common in mammography. The purpose of this study was to make single-scan contrast-enhanced imaging feasible for photon-counting breast CT (pcBCT) and to assess the spectral performance of a pcBCT scanner by evaluating iodine maps and virtual non-contrast (VNC) images.

METHODS

We optimized the settings of a pcBCT to maximize the signal-to-noise ratio between iodinated contrast agent and breast tissue. Therefore, an electronic energy threshold dividing the x-ray spectrum used into two energy bins was swept from 23.17 keV to 50.65 keV. Validation measurements were performed by placing syringes with contrast agent (2.5 mg/ml to 40 mg/ml) in phantoms with 7.5 cm and 12 cm in diameter. Images were acquired at different tube currents and reconstructed with 300 μm isotropic voxel size. Iodine maps and VNC images were generated using image-based material decomposition. Iodine concentrations and CT values were measured for each syringe and compared to the known concentrations and reference CT values.

RESULTS

Maximal signal-to-noise ratios were found at a threshold position of 32.59 keV. Accurate iodine quantification (average root mean square error of 0.56 mg/ml) was possible down to a concentration of 2.5 mg/ml for all tube currents investigated. The enhancement has been sufficiently removed in the VNC images, so they can be interpreted as unenhanced CT images. Only minor changes of CT values compared to a conventional CT scan were observed. Noise was increased by the decomposition by a factor of 2.62 and 4.87 (7.5 cm and 12 cm phantoms) but did not compromise the accuracy of the iodine quantification.

CONCLUSIONS

Accurate iodine quantification and generation of VNC images can be achieved using contrast-enhanced pcBCT from a single CT scan in the absence of temporal or spatial misalignment. Using iodine maps and VNC images, pcBCT has the potential to reduce dose, shorten examination and reading time, and to increase cancer detection rates.

Utility of Supplemental Training to Improve Radiologist Performance in Breast Cancer Screening: A Literature Review

PURPOSE

The authors evaluate whether supplemental training for radiologists improves their breast screening performance and how this is measured.

METHODS

A systematic search was conducted in PubMed on August 3, 2017. Articles were included if they described supplemental training for radiologists reading mammograms to improve their breast screening performance and at least one outcome measure was reported. Study quality was assessed using the Medical Education Research Study Quality Instrument.

RESULTS

Of 2,199 identified articles, 18 were included, of which 17 showed improvement on at least one of the outcome measures, for at least one training activity or subgroup. Two measurement approaches were found. For the first approach, measuring performance on test sets, sensitivity, and specificity were the most reported outcomes (8 of 11 studies). Recall rate is the most reported outcome (6 of 7 studies) for the second approach, which measures performance in actual screening practice. The studies were mainly of moderate quality (Medical Education Research Study Quality Instrument score 11.7 ± 1.7), caused by small sample sizes and the lack of a control group.

CONCLUSIONS

Supplemental training helps radiologists improve their screening performance, despite the mainly moderate quality of the studies. There is a need for better designed studies. Future studies should focus on performance in actual screening practice and should look for methods to isolate the training effect. If test sets are used, focus should be on knowledge about correlation between performance on test sets and actual screening practice.

Medical auditing of whole-breast screening ultrasonography

Since breast ultrasonography (US) has been used as an adjunctive screening modality in women with dense breasts, the need has arisen to evaluate and monitor its possible harm and benefits in comparison with other screening modalities such as mammography. Recently, the fifth edition of the Breast Imaging Reporting and Data System published by the American College of Radiology has suggested auditing methods for screening breast US. However, the method proposed therein is slightly different from how diagnostic performance was calculated in previous studies on screening breast US. In this article, the background and core aspects of medical audits of breast cancer screening will be reviewed to provide an introduction to the medical auditing of screening breast US, with the goal of helping radiologists to understand and identify potential ways to improve outcomes.

Performance of a subsidised mammographic screening programme in Malaysia, a middle-income Asian country

BACKGROUND

The incidence of breast cancer in Asia is increasing because of urbanization and lifestyle changes. In the developing countries in Asia, women present at late stages, and mortality is high. Mammographic screening is the only evidence-based screening modality that reduces breast cancer mortality. To date, only opportunistic screening is offered in the majority of Asian countries because of the lack of justification and funding. Nevertheless, there have been few reports on the effectiveness of such programmes. In this study, we describe the cancer detection rate and challenges experienced in an opportunistic mammographic screening programme in Malaysia.

METHODS

From October 2011 to June 2015, 1,778 asymptomatic women, aged 40-74 years, underwent subsidised mammographic screening. All patients had a clinical breast examination before mammographic screening, and women with mammographic abnormalities were referred to a surgeon. The cancer detection rate and variables associated with a recommendation for adjunct ultrasonography were determined.

RESULTS

The mean age for screening was 50.8 years and seven cancers (0.39%) were detected. The detection rate was 0.64% in women aged 50 years and above, and 0.12% in women below 50 years old. Adjunct ultrasonography was recommended in 30.7% of women, and was significantly associated with age, menopausal status, mammographic density and radiologist's experience. The main reasons cited for recommendation of an adjunct ultrasound was dense breasts and mammographic abnormalities.

DISCUSSION

The cancer detection rate is similar to population-based screening mammography programmes in high-income Asian countries. Unlike population-based screening programmes in Caucasian populations where the adjunct ultrasonography rate is 2-4%, we report that 3 out of 10 women attending screening mammography were recommended for adjunct ultrasonography. This could be because Asian women attending screening are likely premenopausal and hence have denser breasts. Radiologists who reported more than 360 mammograms were more confident in reporting a mammogram as normal without adjunct ultrasonography compared to those who reported less than 180 mammograms.

CONCLUSION

Our subsidised opportunistic mammographic screening programme is able to provide equivalent cancer detection rates but the high recall for adjunct ultrasonography would make screening less cost-effective.

Using computer-extracted image features for modeling of error-making patterns in detection of mammographic masses among radiology residents

PURPOSE

Mammography is the most widely accepted and utilized screening modality for early breast cancer detection. Providing high quality mammography education to radiology trainees is essential, since excellent interpretation skills are needed to ensure the highest benefit of screening mammography for patients. The authors have previously proposed a computer-aided education system based on trainee models. Those models relate human-assessed image characteristics to trainee error. In this study, the authors propose to build trainee models that utilize features automatically extracted from images using computer vision algorithms to predict likelihood of missing each mass by the trainee. This computer vision-based approach to trainee modeling will allow for automatically searching large databases of mammograms in order to identify challenging cases for each trainee.

METHODS

The authors' algorithm for predicting the likelihood of missing a mass consists of three steps. First, a mammogram is segmented into air, pectoral muscle, fatty tissue, dense tissue, and mass using automated segmentation algorithms. Second, 43 features are extracted using computer vision algorithms for each abnormality identified by experts. Third, error-making models (classifiers) are applied to predict the likelihood of trainees missing the abnormality based on the extracted features. The models are developed individually for each trainee using his/her previous reading data. The authors evaluated the predictive performance of the proposed algorithm using data from a reader study in which 10 subjects (7 residents and 3 novices) and 3 experts read 100 mammographic cases. Receiver operating characteristic (ROC) methodology was applied for the evaluation.

RESULTS

The average area under the ROC curve (AUC) of the error-making models for the task of predicting which masses will be detected and which will be missed was 0.607 (95% CI,0.564-0.650). This value was statistically significantly different from 0.5 (p<0.0001). For the 7 residents only, the AUC performance of the models was 0.590 (95% CI,0.537-0.642) and was also significantly higher than 0.5 (p=0.0009). Therefore, generally the authors' models were able to predict which masses were detected and which were missed better than chance.

CONCLUSIONS

The authors proposed an algorithm that was able to predict which masses will be detected and which will be missed by each individual trainee. This confirms existence of error-making patterns in the detection of masses among radiology trainees. Furthermore, the proposed methodology will allow for the optimized selection of difficult cases for the trainees in an automatic and efficient manner.

Evaluation of lossy data compression in primary interpretation for full-field digital mammography

OBJECTIVE. For full-field digital mammography (FFDM), federal regulations prohibit lossy data compression for primary reading and archiving, unlike all other medical images, where reading physicians can apply their professional judgment in implementing lossy compression. Faster image transfer, lower costs, and greater access to expert mammographers would result from development of a safe standard for primary interpretation and archive of lossy-compressed FFDM images. This investigation explores whether JPEG 2000 80:1 lossy data compression affects clinical accuracy in digital mammography. MATERIALS AND METHODS. Randomized FFDM cases (n = 194) were interpreted by six experienced mammographers with and without JPEG 2000 80:1 lossy compression applied. A cancer-enriched population was used, with just less than half of the cases (42%) containing subtle (< 1 cm) biopsy-proven cancerous lesions, and the remaining cases were negative as proven by 2-year follow-up. Data were analyzed using the jackknife alternative free-response ROC (JAFROC) method. RESULTS. The differences in reader performance between lossy-compressed and non-lossy-compressed images using lesion localization (0.660 vs 0.671), true-positive fraction (0.879 vs 0.879), and false-positive fraction (0.283 vs 0.271) were not statistically significant. There was no difference in the JAFROC figure of merit between lossy-compressed and non-lossy-compressed images, with a mean difference of -0.01 (95% CI, -0.03 to 0.01; F1,5 = 2.30; p = 0.189). CONCLUSION. These results suggest that primary interpretation of JPEG 2000 80:1 lossy-compressed FFDM images may be viable without degradation of clinical quality. Benefits would include lower storage costs, faster telemammography, and enhanced access to expert mammographers.

Educational interventions to improve screening mammography interpretation: a randomized controlled trial

OBJECTIVE

The objective of our study was to conduct a randomized controlled trial of educational interventions that were created to improve performance of screening mammography interpretation.

MATERIALS AND METHODS

We randomly assigned physicians who interpret mammography to one of three groups: self-paced DVD, live expert-led educational seminar, or control. The DVD and seminar interventions used mammography cases of varying difficulty and provided associated teaching points. Interpretive performance was compared using a pretest-posttest design. Sensitivity, specificity, and positive predictive value (PPV) were calculated relative to two outcomes: cancer status and consensus of three experts about recall. The performance measures for each group were compared using logistic regression adjusting for pretest performance.

RESULTS

One hundred two radiologists completed all aspects of the trial. After adjustment for preintervention performance, the odds of improved sensitivity for correctly identifying a lesion relative to expert recall were 1.34 times higher for DVD participants than for control subjects (95% CI, 1.00-1.81; p = 0.050). The odds of an improved PPV for correctly identifying a lesion relative to both expert recall (odds ratio [OR] = 1.94; 95% CI, 1.24-3.05; p = 0.004) and cancer status (OR = 1.81; 95% CI, 1.01-3.23; p = 0.045) were significantly improved for DVD participants compared with control subjects, with no significant change in specificity. For the seminar group, specificity was significantly lower than the control group (OR relative to expert recall = 0.80; 95% CI, 0.64-1.00; p = 0.048; OR relative to cancer status = 0.79; 95% CI, 0.65-0.95; p = 0.015).

CONCLUSION

In this randomized controlled trial, the DVD educational intervention resulted in a significant improvement in screening mammography interpretive performance on a test set, which could translate into improved interpretative performance in clinical practice.

A Performance Weighted Collaborative Filtering algorithm for personalized radiology education

Devising an accurate prediction algorithm that can predict the difficulty level of cases for individuals and then selects suitable cases for them is essential to the development of a personalized training system. In this paper, we propose a novel approach, called Performance Weighted Collaborative Filtering (PWCF), to predict the difficulty level of each case for individuals. The main idea of PWCF is to assign an optimal weight to each rating used for predicting the difficulty level of a target case for a trainee, rather than using an equal weight for all ratings as in traditional collaborative filtering methods. The assigned weight is a function of the performance level of the trainee at which the rating was made. The PWCF method and the traditional method are compared using two datasets. The experimental data are then evaluated by means of the MAE metric. Our experimental results show that PWCF outperforms the traditional methods by 8.12% and 17.05%, respectively, over the two datasets, in terms of prediction precision. This suggests that PWCF is a viable method for the development of personalized training systems in radiology education.

A content-boosted collaborative filtering algorithm for personalized training in interpretation of radiological imaging

Devising a method that can select cases based on the performance levels of trainees and the characteristics of cases is essential for developing a personalized training program in radiology education. In this paper, we propose a novel hybrid prediction algorithm called content-boosted collaborative filtering (CBCF) to predict the difficulty level of each case for each trainee. The CBCF utilizes a content-based filtering (CBF) method to enhance existing trainee-case ratings data and then provides final predictions through a collaborative filtering (CF) algorithm. The CBCF algorithm incorporates the advantages of both CBF and CF, while not inheriting the disadvantages of either. The CBCF method is compared with the pure CBF and pure CF approaches using three datasets. The experimental data are then evaluated in terms of the MAE metric. Our experimental results show that the CBCF outperforms the pure CBF and CF methods by 13.33 and 12.17 %, respectively, in terms of prediction precision. This also suggests that the CBCF can be used in the development of personalized training systems in radiology education.

Feasibility and acceptability of conducting a randomized clinical trial designed to improve interpretation of screening mammography

PURPOSE

To describe recruitment, enrollment, and participation in a study of US radiologists invited to participate in a randomized controlled trial of two continuing medical education (CME) interventions designed to improve interpretation of screening mammography.

METHODS

We collected recruitment, consent, and intervention-completion information as part of a large study involving radiologists in California, Oregon, Washington, New Mexico, New Hampshire, North Carolina, and Vermont. Consenting radiologists were randomized to receive either a 1-day live, expert-led educational session; to receive a self-paced DVD with similar content; or to a control group (delayed intervention). The impact of the interventions was assessed using a preintervention-postintervention test set design. All activities were institutional review board approved and HIPAA compliant.

RESULTS

Of 403 eligible radiologists, 151 of 403 (37.5%) consented to participate in the trial and 119 of 151 (78.8%) completed the preintervention test set, leaving 119 available for randomization to one of the two intervention groups or to controls. Female radiologists were more likely than male radiologists to consent to and complete the study (P = .03). Consenting radiologists who completed all study activities were more likely to have been interpreting mammography for 10 years or less compared to radiologists who consented and did not complete all study activities or did not consent at all. The live intervention group was more likely to report their intent to change their clinical practice as a result of the intervention compared to those who received the DVD (50% versus 17.6%, P = .02). The majority of participants in both interventions groups felt the interventions were a useful way to receive CME mammography credits.

CONCLUSIONS

Community radiologists found interactive interventions designed to improve interpretative mammography performance acceptable and useful for clinical practice. This suggests CME credits for radiologists should, in part, be for examining practice skills.

Impact of an educational intervention designed to reduce unnecessary recall during screening mammography

RATIONALE AND OBJECTIVES

The aim of this study was to describe the impact of a tailored Web-based educational program designed to reduce excessive screening mammography recall.

MATERIALS AND METHODS

Radiologists enrolled in one of four mammography registries in the United States were invited to take part and were randomly assigned to receive the intervention or to serve as controls. The controls were offered the intervention at the end of the study, and data collection included an assessment of their clinical practice as well. The intervention provided each radiologist with individual audit data for his or her sensitivity, specificity, recall rate, positive predictive value, and cancer detection rate compared to national benchmarks and peer comparisons for the same measures; profiled breast cancer risk in each radiologist's respective patient populations to illustrate how low breast cancer risk is in population-based settings; and evaluated the possible impact of medical malpractice concerns on recall rates. Participants' recall rates from actual practice were evaluated for three time periods: the 9 months before the intervention was delivered to the intervention group (baseline period), the 9 months between the intervention and control groups (T1), and the 9 months after completion of the intervention by the controls (T2). Logistic regression models examining the probability that a mammogram was recalled included indication of intervention versus control and time period (baseline, T1, and T2). Interactions between the groups and time period were also included to determine if the association between time period and the probability of a positive result differed across groups.

RESULTS

Thirty-one radiologists who completed the continuing medical education intervention were included in the adjusted model comparing radiologists in the intervention group (n = 22) to radiologists who completed the intervention in the control group (n = 9). At T1, the intervention group had 12% higher odds of positive mammographic results compared to the controls, after controlling for baseline (odds ratio, 1.12; 95% confidence interval, 1.00-1.27; P = .0569). At T2, a similar association was found, but it was not statistically significant (odds ratio, 1.10; 95% confidence interval, 0.96 to 1.25). No associations were found among radiologists in the control group when comparing those who completed the continuing medical education intervention (n = 9) to those who did not (n = 10). In addition, no associations were found between time period and recall rate among radiologists who set realistic goals.

CONCLUSIONS

This study resulted in a null effect, which may indicate that a single 1-hour intervention is not adequate to change excessive recall among radiologists who undertook the intervention being tested.

Identifying error-making patterns in assessment of mammographic BI-RADS descriptors among radiology residents using statistical pattern recognition

RATIONALE AND OBJECTIVE

The objective of this study is to test the hypothesis that there are patterns in erroneous assessment of BI-RADS features among radiology trainees when interpreting mammographic masses and that these patterns can be captured in individualized statistical user models. Identifying these patterns could be useful in personalizing and adapting educational material to complement the individual weaknesses of each trainee during his or her mammography education.

MATERIALS AND METHODS

Reading data of 33 mammographic cases containing masses was used. The cases were individually described by 10 radiology residents using four BI-RADS features: mass shape, mass margin, mass density and parenchyma density. For each resident, an individual model was automatically constructed that predicts likelihood (HIGH or LOW) of erroneously assigning each BI-RADS descriptor by the resident. Error was defined as deviation of the resident's assessment from the expert assessments. We evaluated the predictive performance of the models using leave-one-out crossvalidation.

RESULTS

The user models were able to predict which assessments have higher likelihood of error. The proportion of actual errors to the number of situations in which these errors could potentially occur was significantly higher (P < .05) when user-model assigned HIGH likelihood of error than when LOW likelihood of error was assigned for three of the four BI-RADS features. Overall, the difference between the HIGH and LOW likelihood of error groups was statistically significant (P < .0001) combining all four features.

CONCLUSION

Error making in BI-RADS descriptor assessment appears to follow patterns that can be captured with statistical pattern recognition-based user models.

Surgical mammography reporting in a limited resource environment

BACKGROUND

Lack of resources and dedicated breast radiology has forced professionals other than radiologists to read mammography. We report a series of surgeon-read mammography in a developing country.

METHODS

Data were collected prospectively form January 2003 to June 2008 for all mammography performed at a tertiary hospital. The data acquired were demographics, previous treatment for breast pathology, and indication for and outcome of mammography, including diagnostic procedures and their results. The results were benchmarked against standard performance indicators.

RESULTS

Of 8,743 mammograms performed, 1,468 were for palpable lumps; the cancer diagnosis rate was 640 per 1,000 investigations (for 885 of these reported as compatible with malignancy, the cancer diagnosis rate was 95%; for 183 reported as indeterminate 60%, for 400 reported as benign/no abnormality 4%). Of 4,998 cancer follow-up mammograms, the cancer diagnosis rate was 15 per 1,000. For 76 of these reported as compatible with malignancy, the cancer diagnosis rate was 67%, for 161 reported as indeterminate, the biopsy rate was 36%, and cancer diagnosis rates of biopsy was 41%. Of 75 cancers diagnosed, 26 were locally recurrent after breast conservation and 49 new contralateral primaries, 84% of these were stage 0-I. Of 2,001 mammograms performed for screening, the biopsy rate was 4.5% and the cancer diagnosis rate of biopsy was 27%; the overall cancer diagnosis rate was 11 per 1,000 examinations; 96% of these were stage 0-1.

CONCLUSIONS

Dedicated breast surgeons are equally proficient at mammography interpretation as radiologists. In resource-restricted environments, nonavailability of dedicated breast radiologists should not preclude development of breast units.

Interactive dedicated training curriculum improves accuracy in the interpretation of MR imaging of prostate cancer

OBJECTIVE

To assess the effect of interactive dedicated training on radiology fellows' accuracy in assessing prostate cancer on MRI.

METHODS

Eleven radiology fellows, blinded to clinical and pathological data, independently interpreted preoperative prostate MRI studies, scoring the likelihood of tumour in the peripheral and transition zones and extracapsular extension. Each fellow interpreted 15 studies before dedicated training (to supply baseline interpretation accuracy) and 200 studies (10/week) after attending didactic lectures. Expert radiologists led weekly interactive tutorials comparing fellows' interpretations to pathological tumour maps. To assess interpretation accuracy, receiver operating characteristic (ROC) analysis was conducted, using pathological findings as the reference standard.

RESULTS

In identifying peripheral zone tumour, fellows' average area under the ROC curve (AUC) increased from 0.52 to 0.66 (after didactic lectures; p<0.0001) and remained at 0.66 (end of training; p<0.0001); in the transition zone, their average AUC increased from 0.49 to 0.64 (after didactic lectures; p=0.01) and to 0.68 (end of training; p=0.001). In detecting extracapsular extension, their average AUC increased from 0.50 to 0.67 (after didactic lectures; p=0.003) and to 0.81 (end of training; p<0.0001).

CONCLUSION

Interactive dedicated training significantly improved accuracy in tumour localization and especially in detecting extracapsular extension on prostate MRI.

Individualized computer-aided education in mammography based on user modeling: concept and preliminary experiments

PURPOSE

The authors propose the framework for an individualized adaptive computer-aided educational system in mammography that is based on user modeling. The underlying hypothesis is that user models can be developed to capture the individual error making patterns of radiologists-in-training. In this pilot study, the authors test the above hypothesis for the task of breast cancer diagnosis in mammograms.

METHODS

The concept of a user model was formalized as the function that relates image features to the likelihood/extent of the diagnostic error made by a radiologist-in-training and therefore to the level of difficulty that a case will pose to the radiologist-in-training (or "user"). Then, machine learning algorithms were implemented to build such user models. Specifically, the authors explored k-nearest neighbor, artificial neural networks, and multiple regression for the task of building the model using observer data collected from ten Radiology residents at Duke University Medical Center for the problem of breast mass diagnosis in mammograms. For each resident, a user-specific model was constructed that predicts the user's expected level of difficulty for each presented case based on two BI-RADS image features. In the experiments, leave-one-out data handling scheme was applied to assign each case to a low-predicted-difficulty or a high-predicted-difficulty group for each resident based on each of the three user models. To evaluate whether the user model is useful in predicting difficulty, the authors performed statistical tests using the generalized estimating equations approach to determine whether the mean actual error is the same or not between the low-predicted-difficulty group and the high-predicted-difficulty group.

RESULTS

When the results for all observers were pulled together, the actual errors made by residents were statistically significantly higher for cases in the high-predicted-difficulty group than for cases in the low-predicted-difficulty group for all modeling algorithms (p < or = 0.002 for all methods). This indicates that the user models were able to accurately predict difficulty level of the analyzed cases. Furthermore, the authors determined that among the two BI-RADS features that were used in this study, mass margin was the most useful in predicting individual user errors.

CONCLUSIONS

The pilot study shows promise for developing individual user models that can accurately predict the level of difficulty that each case will pose to the radiologist-in-training. These models could allow for constructing adaptive computer-aided educational systems in mammography.

A radiologist's perspective on efficiency and economics in a quality breast center

As a former general radiologist and current full time clinical breast radiologist, I have observed and experienced both good and suboptimal practice patterns, operations, and economics. Proper organization of a high quality, efficient breast center requires basic infrastructure including functional space, quality imaging equipment, data reporting systems, as well as a highly motivated, dedicated, and focused team. People on the breast care team need to share the same passion and commitment to provide superior care for patients and families. Each member of this interdisciplinary team provides an important role that contributes to best practices and patient satisfaction. Efficiency and quality are essential for the long-term survival of clinical breast radiology, a highly regulated and scrutinized medical subspecialty. This paper reflects personal perspectives and perceptions about how to make a good breast care practice great by incorporating strategies such as the simple hedgehog concept used in other successful businesses.

Qualidade da interpretação do diagnóstico mamográfico

OBJETIVO: Demonstrar o conhecimento mamográfico dos médicos interpretadores que trabalham na rede de saúde pública do Estado do Rio de Janeiro e avaliar o conhecimento adquirido após um curso elaborado com o objetivo de capacitar profissionais médicos no diagnóstico precoce do câncer de mama. MATERIAIS E MÉTODOS: Foram convidados 53 médicos que laudam exames mamográficos para o treinamento. Esses médicos eram submetidos a um pré-teste, no qual se avaliava o grau de conhecimento inicial. Depois, foram lecionadas aulas previamente elaboradas por mamografistas experientes, e para conclusão do curso esses médicos eram submetidos a um pós-teste para avaliação do conhecimento adquirido. RESULTADOS: O curso de capacitação de profissionais médicos, com ênfase em aulas teóricas, não mostrou aumento significativo na qualidade da interpretação mamográfica, destacando-se a persistência do erro na descrição morfológica das lesões fundamentais da mama, erro da classificação pelo sistema de padronização das lesões mamárias (BI-RADS®), falta de coerência entre a classificação BI-RADS adotada e a recomendação de conduta, tanto no pré-teste como no pós-teste. CONCLUSÃO: Concluiu-se que os médicos interpretadores mostram conhecimento insuficiente em relação ao diagnóstico precoce por imagem do câncer de mama e que o curso teórico não mostrou aumento significativo na qualidade da interpretação mamográfica.

When radiologists perform best: the learning curve in screening mammogram interpretation

PURPOSE

To examine changes in screening mammogram interpretation as radiologists with and radiologists without fellowship training in breast imaging gain clinical experience.

MATERIALS AND METHODS

In an institutional review board-approved HIPAA-compliant study, the performance of 231 radiologists who interpreted screen-film screening mammograms from 1996 to 2005 at 280 facilities that contribute data to the Breast Cancer Surveillance Consortium was examined. Radiologists' demographic data and clinical experience levels were collected by means of a mailed survey. Mammograms were grouped on the basis of how many years the interpreting radiologist had been practicing mammography, and the influence of increasing experience on performance was examined separately for radiologists with and those without fellowship training in breast imaging, taking into account case-mix and radiologist-level differences.

RESULTS

A total of 1 599 610 mammograms were interpreted during the study period. Performance for radiologists without fellowship training improved most during their 1st 3 years of clinical practice, when the odds of a false-positive reading dropped 11%-15% per year (P < .015) with no associated decrease in sensitivity (P > .89). The number of women recalled per breast cancer detected decreased from 33 for radiologists in their 1st year of practice to 24 for radiologists with 3 years of experience to 19 for radiologists with 20 years of experience. Radiologists with fellowship training in breast imaging experienced no learning curve and reached desirable goals during their 1st year of practice.

CONCLUSION

Radiologists' interpretations of screening mammograms improve during their first few years of practice and continue to improve throughout much of their careers. Additional residency training and targeted continuing medical education may help reduce the number of work-ups of benign lesions while maintaining high cancer detection rates.

Variability in interpretive performance at screening mammography and radiologists' characteristics associated with accuracy

PURPOSE

To identify radiologists' characteristics associated with interpretive performance in screening mammography.

MATERIALS AND METHODS

The study was approved by institutional review boards of University of Washington (Seattle, Wash) and institutions at seven Breast Cancer Surveillance Consortium sites, informed consent was obtained, and procedures were HIPAA compliant. Radiologists who interpreted mammograms in seven U.S. regions completed a self-administered mailed survey; information on demographics, practice type, and experience in and perceptions of general radiology and breast imaging was collected. Survey data were linked to data on screening mammograms the radiologists interpreted between January 1, 1998, and December 31, 2005, and included patient risk factors, Breast Imaging Reporting and Data System assessment, and follow-up breast cancer data. The survey was returned by 71% (257 of 364) of radiologists; in 56% (205 of 364) of the eligible radiologists, complete data on screening mammograms during the study period were provided; these data were used in the final analysis. An evaluation of whether the radiologists' characteristics were associated with recall rate, false-positive rate, sensitivity, or positive predictive value of recall (PPV(1)) of the screening examinations was performed with logistic regression models that were adjusted for patients' characteristics and radiologist-specific random effects.

RESULTS

Study radiologists interpreted 1 036 155 screening mammograms; 4961 breast cancers were detected. Median percentages and interquartile ranges, respectively, were as follows: recall rate, 9.3% and 6.3%-13.2%; false-positive rate, 8.9% and 5.9%-12.8%; sensitivity, 83.8% and 74.5%-92.3%; and PPV(1), 4.0% and 2.6%-5.9%. Wide variability in sensitivity was noted, even among radiologists with similar false-positive rates. In adjusted regression models, female radiologists or fellowship-trained radiologists had significantly higher recall and false-positive rates (P < .05, all). Fellowship training in breast imaging was the only characteristic significantly associated with improved sensitivity (odds ratio, 2.32; 95% confidence interval: 1.42, 3.80; P < .001) and the overall accuracy parameter (odds ratio, 1.61; 95% confidence interval: 1.05, 2.45; P = .028).

CONCLUSION

Fellowship training in breast imaging may lead to improved cancer detection, but it is associated with higher false-positive rates.

Errors in cancer diagnosis: current understanding and future directions

PURPOSE

Errors in cancer diagnosis are likely the most harmful and expensive types of diagnostic errors. We reviewed the literature to understand the prevalence, origins, and prevention of errors in cancer diagnosis, focusing on common cancers for which early diagnosis offers clear benefit (melanoma and cancers of the breast, colon, and lung).

METHODS

We searched the Cochrane Library and PubMed from 1966 until April 2007 for publications that met our review criteria and manually searched references of key publications. Our search yielded 110 studies, of which nine were prospective studies and the remaining were retrospective studies.

RESULTS

Errors in cancer diagnosis were not uncommon in autopsy studies and were associated with significant harm and expense in malpractice claims. Literature on prevalence was scant. For each type of cancer, we classified preventable errors according to their origins in patient-physician encounters in the clinic setting, diagnostic test or procedure performance, pathologic confirmation of diagnosis, follow-up of patient or test result, or patient-related delays.

CONCLUSION

The literature reflects advanced knowledge of contributory factors and prevention for diagnostic errors related to the performance of procedures and imaging tests and emerging understanding of pathology errors. However, prospective studies are few, as are studies of diagnostic errors arising from the clinical encounter and patient follow-up. Future research should examine further the system and cognitive problems that lead to the many contributory factors we identified, and address interdisciplinary interventions to prevent errors in cancer diagnosis.

Quality and variability in diagnostic radiology

Achieving and delivering optimal quality of care in radiology requires continual self-examination by the profession, particularly with regard to technical, interpretive, and communication skills. The importance of empirical data pertaining to quality and variability in radiology, the underlying causes of error, and the sources of variability are discussed. Key measures (e.g., receiver operating characteristics, kappa) and approaches (professional audits and peer reviews, surveys, inspections, and risk management programs) used in improvement efforts are reviewed, and data from key studies are highlighted. Diagnostic errors are important because of their connection to outcomes and the wide variability observed with modalities such as chest radiography and mammography.

BI-RADS: Use in the French radiologic community

In the United States, BI-RADS (Breast Imaging Reporting and Data System) has been set up as a quality assurance system for better communication between professionals and for the follow-up of breast screening programs. It has become a reference in the field of mammographic imaging and has been adopted by several countries throughout the world. It has been translated in French. The aim of this article is to discuss the difficulties in using it in the French radiologic communities. There are few problems with vocabulary excepted for microcalcifications. BI-RADS includes a guidance chapter giving some recommendations for using properly the lexicon. Classification of normal breast remains of concern, as it is difficult to evaluate precisely the content of fat and as the final image is also dependant of technical factors. The main difficulties are related to final classification in BI-RADS categories as the lexicon does not explicit which mammographic features should be included in the categories from three to five. In France, a table concerning the classification of mammographic abnormalities has been established by the HAS (former ANAES) which represents the highest scientific health authority in France. There are no major problems for using the BI-RADS for US and MRI. BI-RADS is suitable for different categories of women and for male and training has an important impact on acceptance and proper use of the lexicon.

Performance benchmarks for screening mammography

PURPOSE

To retrospectively evaluate the range of performance outcomes of the radiologist in an audit of screening mammography by using a representative sample of U.S. radiologists to allow development of performance benchmarks for screening mammography.

MATERIALS AND METHODS

Institutional review board approval was obtained, and study was HIPAA compliant. Informed consent was or was not obtained according to institutional review board guidelines. Data from 188 mammographic facilities and 807 radiologists obtained between 1996 and 2002 were analyzed from six registries from the Breast Cancer Surveillance Consortium (BCSC). Contributed data included demographic information, clinical findings, mammographic interpretation, and biopsy results. Measurements calculated were positive predictive values (PPVs) from screening mammography (PPV(1)), biopsy recommendation (PPV(2)), biopsy performed (PPV(3)), recall rate, cancer detection rate, mean cancer size, and cancer stage. Radiologist performance data are presented as 50th (median), 10th, 25th, 75th, and 90th percentiles and as graphic presentations by using smoothed curves.

RESULTS

There were 2 580 151 screening mammographic studies from 1 117 390 women (age range, <30 to >/=80 years). The respective means and ranges of performance outcomes for the middle 50% of radiologists were as follows: recall rate, 9.8% and 6.4%-13.3%; PPV(1), 4.8% and 3.4%-6.2%; and PPV(2), 24.6% and 18.8%-32.0%. Mean cancer detection rate was 4.7 per 1000, and the median [corrected] mean size of invasive cancers was 13 mm. The range of performance outcomes for the middle 80% of radiologists also was presented.

CONCLUSION

Community screening mammographic performance measurements of cancer outcomes for the majority of radiologists in the BCSC surpass performance recommendations. Recall rate for almost half of radiologists, however, is higher than the recommended rate.

Randomized Clinical Trials for Cancer Screening: Rationale and Design Considerations for Imaging Tests

Since the 1960s, there have been revolutionary developments in imaging technology. Undoubtedly, these advances in imaging technology have made it possible to detect most cancers much earlier than they would have presented with clinical signs or symptoms. However, there are harms from screening, including false-positive results and overdiagnosis, and the costs of screening can be substantial. Therefore, screening for cancer must be rigorously evaluated to ensure that it provides more benefit than harm at an acceptable cost. Unfortunately, the evaluation of cancer screening is difficult and susceptible to several forms of bias. Randomized clinical trials are the most valid study design for cancer screening, but they cannot be expected to answer all the questions that arise with the implementation of screening. Decision modeling can be used to extrapolate the results of randomized clinical trials to help inform public policy and individual decision making.

Lesion detection and characterization in a breast US phantom: results of the ACRIN 6666 Investigators

PURPOSE

To prospectively evaluate ultrasonographic (US) lesion detection and characterization in a breast phantom by potential investigators in a screening US protocol, American College of Radiology Imaging Network (ACRIN) 6666.

MATERIALS AND METHODS

National Cancer Institute Cancer Experimental Therapeutic Protocol review and ACRIN internal institutional review board approved the protocol; potential investigators were informed of the study purpose prior to participation. Six equivalent anthropomorphic phantoms were prepared with 17 masses (2-10 mm in mean diameter) in different locations at different depths. Sixty-six investigators, experienced in breast US, from 23 institutions scanned a phantom with high-frequency linear-array transducers (12-5 MHz). Lesion location, diameters, echogenicity, shape, and posterior features were recorded. Reader-specific phantom maps were generated and compared with known lesion locations and features. Results from 64 observers could be analyzed and were masked to investigator identity. Agreement on US features was measured with kappa statistics. A generalized linear model generated log relative risks for detection rates as a function of lesion diameter, depth, and features.

RESULTS

Of 17 lesions, a median of 14 (82%) were detected (range, 9-16), and 86% of observers detected at least 12 lesions. Of 1088 potential detections, 861 (79.1%) were made. Among 5-10-mm lesions, 499 (97.5%) of 512 detections were made (excluding a 6-mm "skin" lesion seen by only seven observers [11%]). One 4-mm mass was seen by 53 observers (83%). Among 3-mm lesions, 274 (71.4%) of 384 detections were made. One 2-mm lesion was seen by 28 (44%) observers. Relative risk of detection decreased to 0.55 (95% confidence interval: 0.51, 0.59) for each centimeter increase in lesion depth. Agreement was slight for lesion shape (kappa=0.14), substantial for echogenicity (kappa=0.61), and moderate for posterior features (kappa=0.45). Feature description errors were common for 2-4-mm lesions; only 33% of 3-mm anechoic masses were so characterized. Among eight 6-10-mm lesions, investigators erred in feature description of a median of 1 lesion (mean, 1.3; range, 0-4).

CONCLUSION

US detection and description of lesions in a breast phantom were highly consistent for lesions 5-10 mm in diameter; those smaller than 5 mm were less reliably identified or characterized by experienced investigators.

Performance of clinical mammography: A nationwide study from Denmark

Clinical mammography is the key tool for breast cancer diagnosis, but little is known about the impact of the organisational set-up on the performance. We evaluated whether organisational factors influence the performance of clinical mammography. Clinical mammography data from all clinics in Denmark in the year 2000 were collected and linked to cancer outcome. Use of the National Institute of Radiation Hygiene register for identification of radiology clinics ensured comprehensive nationwide registration. We used the final mammographic assessment at the end of the imaging work-up to determine sensitivity, specificity and accuracy, the latter using a receiver-operating characteristics (ROC) analysis. In 96,534 clinical mammography examinations, sensitivity was 75% and specificity 99%. The presence of at least one high volume-reading radiologist in the clinic increased accuracy (AUC = 0.91 for <1,000 examinations/year and 0.92 for >2,000 examinations/year, p = 0.017). The examination volume per clinic showed no clear effect on performance, as accuracy was significantly higher in clinics with a medium number of examinations (AUC = 0.93 for 2,000-4,000 examinations/year and 0.90 for >6,000 examinations/year, p = 0.003). Accuracy was significantly lower in regions with high annual utilisation rate of clinical mammography, which means the proportion of examined women in a region (AUC = 0.90 for 3.0-5.0% annual utilisation rate and AUC = 0.93 for 2.0-2.5% annual utilisation rate, and p = 0.001), indicating that clinical mammography worked best in patient populations of purely symptomatic women. Our data indicate that to increase the accuracy of clinical mammography at the community level, the presence of an experienced radiologist should be prioritized ahead of raising the clinic size.

Screening for Breast Cancer

Strong evidence supports the value of breast cancer screening with mammography, and high-quality mammography screening can be considered a major public health achievement. As noted earlier in the discussion about the evaluation of service screening, the group of women who did not participate in mammographic screening in the decades after screening had been introduced had essentially unchanged or only minor improvements in mortality compared with the pattern before the introduction of screening, despite widespread use of adjuvant chemotherapy or hormonal therapy. Breast cancer should be treated in its preclinical phase if we are to save the lives of women with this disease, and a considerable body of evidence outlines best practices that, with broader adherence, would result in greater breast cancer mortality reductions than have been observed to date.

The use of additional imaging increased specificity and decreased sensitivity in screening mammography

BACKGROUND AND OBJECTIVES

To examine the use of additional imaging after standard mammographic screening views to better understand the value of these additional testing in improving accuracy.

MATERIALS AND METHODS

Statewide population data on screening mammography were used to report accuracy measures at screening and after additional imaging tests. Pathology data from biopsies performed within 1 year following the screening mammogram were used to determine cancer outcome (489 in situ and invasive cancers). Pathologic and population characteristics of women receiving different types of imaging were assessed by chi-square or t-tests. Similar tests compared women with the same imaging and differing outcomes.

RESULTS

Of 77,799 women with screening mammograms 9.9% had additional imaging. Additional imaging reduced false positives from 7,765 (100/1,000 mammograms) to 1,112 (14/1,000 mammograms). The majority of false negatives (82%) occurred in women receiving only screening views, and additional imaging increased the number of false negatives from 82 (1/1,000 mammograms) to 115 (1.5/1,000 mammograms).

CONCLUSION

Additional imaging can reduce unnecessary biopsy but at the cost of some additional false negatives. Additional imaging's potential for improving the sensitivity of screening is limited because most missed cancers occur in women who do not have additional imaging.

Screening for breast cancer

CONTEXT

Breast cancer screening in community practices may be different from that in randomized controlled trials. New screening modalities are becoming available.

OBJECTIVES

To review breast cancer screening, especially in the community and to examine evidence about new screening modalities.

DATA SOURCES AND STUDY SELECTION

English-language articles of randomized controlled trials assessing effectiveness of breast cancer screening were reviewed, as well as meta-analyses, systematic reviews, studies of breast cancer screening in the community, and guidelines. Also, studies of newer screening modalities were assessed.

DATA SYNTHESIS

All major US medical organizations recommend screening mammography for women aged 40 years and older. Screening mammography reduces breast cancer mortality by about 20% to 35% in women aged 50 to 69 years and slightly less in women aged 40 to 49 years at 14 years of follow-up. Approximately 95% of women with abnormalities on screening mammograms do not have breast cancer with variability based on such factors as age of the woman and assessment category assigned by the radiologist. Studies comparing full-field digital mammography to screen film have not shown statistically significant differences in cancer detection while the impact on recall rates (percentage of screening mammograms considered to have positive results) was unclear. One study suggested that computer-aided detection increases cancer detection rates and recall rates while a second larger study did not find any significant differences. Screening clinical breast examination detects some cancers missed by mammography, but the sensitivity reported in the community is lower (28% to 36%) than in randomized trials (about 54%). Breast self-examination has not been shown to be effective in reducing breast cancer mortality, but it does increase the number of breast biopsies performed because of false-positives. Magnetic resonance imaging and ultrasound are being studied for screening women at high risk for breast cancer but are not recommended for screening the general population. Sensitivity of magnetic resonance imaging in high-risk women has been found to be much higher than that of mammography but specificity is generally lower. Effect of the magnetic resonance imaging on breast cancer mortality is not known. A balanced discussion of possible benefits and harms of screening should be undertaken with each woman.

CONCLUSIONS

In the community, mammography remains the main screening tool while the effectiveness of clinical breast examination and self-examination are less. New screening modalities are unlikely to replace mammography in the near future for screening the general population.

Physician Predictors of Mammographic Accuracy

BACKGROUND

The association between physician experience and the accuracy of screening mammography in community practice is not well studied. We identified characteristics of U.S. physicians associated with the accuracy of screening mammography.

METHODS

Data were obtained from the Breast Cancer Surveillance Consortium and the American Medical Association Master File. Unadjusted mammography sensitivity and specificity were calculated according to physician characteristics. We modeled mammography sensitivity and specificity by multivariable logistic regression as a function of patient and physician characteristics. All statistical tests were two-sided.

RESULTS

We studied 209 physicians who interpreted 1,220,046 screening mammograms from January 1, 1995, through December 31, 2000, of which 7143 (5.9 per 1000 mammograms) were associated with breast cancer within 12 months of screening. Each physician interpreted a mean of 6011 screening mammograms (95% confidence interval [CI] = 4998 to 6677), including a mean of 34 (95% CI = 28 to 40) from women diagnosed with breast cancer. The mean sensitivity was 77% (range = 29%-97%), and the mean false-positive rate was 10% (range = 1%-29%). After adjustment for the patient characteristics of those whose mammograms they interpreted, physician characteristics were strongly associated with specificity. Higher specificity was associated with at least 25 years (versus less than 10 years) since receipt of a medical degree (for physicians practicing for 25-29 years, odds ratio [OR] = 1.54, 95% CI = 1.14 to 2.08; P = .006), interpretation of 2500-4000 (versus 481-750) screening mammograms annually (OR = 1.30, 95% CI = 1.06 to 1.59; P = .011) and a high focus on screening mammography compared with diagnostic mammography (OR = 1.59, 95% CI = 1.37 to 1.82; P<.001). Higher overall accuracy was associated with more experience and with a higher focus on screening mammography. Compared with physicians who interpret 481-750 mammograms annually and had a low screening focus, physicians who interpret 2500-4000 mammograms annually and had a high screening focus had approximately 50% fewer false-positive examinations and detected a few less cancers.

CONCLUSION

Raising the annual volume requirements in the Mammography Quality Standards Act might improve the overall quality of screening mammography in the United States.

Adverse effects of screening mammography

The main risks and other adverse consequences from screening mammography include discomfort from breast compression, patient recall for additional imaging, and false positive biopsies. Although these risks affect a larger number of women than those who benefit from screening, the risks are less consequential than the life-sparing benefits from early detection. Radiation risk, even for multiple screenings, is negligible at current mammography doses. Anxiety before screening or resulting from supplementary imaging work-up, short-term follow-up, cyst aspiration, and biopsy has not dampened the enthusiasm of most women for the value of early detection.

Digital mammography

Despite its technical advantages, early clinical trials comparing digital mammography with film mammography for screening have been somewhat disappointing. Digital mammography,however, is in its infancy and can be expected to improve more rapidly than film mammography. Some areas of improvement being observed now include the development of new detector technologies; more powerful and better-designed interpretation workstations; and novel advanced applications, such as tomosynthesis and contrast-enhanced mammography, which are not possible with standard film mammography.