Breast MRI during Neoadjuvant Chemotherapy: Lack of Background Parenchymal Enhancement Suppression and Inferior Treatment Response.

Background Suppression of background parenchymal enhancement (BPE) is commonly observed after neoadjuvant chemotherapy (NAC) at contrast-enhanced breast MRI. It was hypothesized that nonsuppressed BPE may be associated with inferior response to NAC. Purpose To investigate the relationship between lack of BPE suppression and pathologic response. Materials and Methods A retrospective review was performed for women with menopausal status data who were treated for breast cancer by one of 10 drug arms (standard NAC with or without experimental agents) between May 2010 and November 2016 in the Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging and Molecular Analysis 2, or I-SPY 2 TRIAL (NCT01042379). Patients underwent MRI at four points: before treatment (T0), early treatment (T1), interregimen (T2), and before surgery (T3). BPE was quantitatively measured by using automated fibroglandular tissue segmentation. To test the hypothesis effectively, a subset of examinations with BPE with high-quality segmentation was selected. BPE change from T0 was defined as suppressed or nonsuppressed for each point. The Fisher exact test and the Z tests of proportions with Yates continuity correction were used to examine the relationship between BPE suppression and pathologic complete response (pCR) in hormone receptor (HR)-positive and HR-negative cohorts. Results A total of 3528 MRI scans from 882 patients (mean age, 48 years ± 10 [standard deviation]) were reviewed and the subset of patients with high-quality BPE segmentation was determined (T1, 433 patients; T2, 396 patients; T3, 380 patients). In the HR-positive cohort, an association between lack of BPE suppression and lower pCR rate was detected at T2 (nonsuppressed vs suppressed, 11.8% [six of 51] vs 28.9% [50 of 173]; difference, 17.1% [95% CI: 4.7, 29.5]; P = .02) and T3 (nonsuppressed vs suppressed, 5.3% [two of 38] vs 27.4% [48 of 175]; difference, 22.2% [95% CI: 10.9, 33.5]; P = .003). In the HR-negative cohort, patients with nonsuppressed BPE had lower estimated pCR rate at all points, but the P values for the association were all greater than .05. Conclusions In hormone receptor-positive breast cancer, lack of background parenchymal enhancement suppression may indicate inferior treatment response. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Philpotts in this issue.

Predicting breast cancer response to neoadjuvant treatment using multi-feature MRI: results from the I-SPY 2 TRIAL.

Dynamic contrast-enhanced (DCE) MRI provides both morphological and functional information regarding breast tumor response to neoadjuvant chemotherapy (NAC). The purpose of this retrospective study is to test if prediction models combining multiple MRI features outperform models with single features. Four features were quantitatively calculated in each MRI exam: functional tumor volume, longest diameter, sphericity, and contralateral background parenchymal enhancement. Logistic regression analysis was used to study the relationship between MRI variables and pathologic complete response (pCR). Predictive performance was estimated using the area under the receiver operating characteristic curve (AUC). The full cohort was stratified by hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status (positive or negative). A total of 384 patients (median age: 49 y/o) were included. Results showed analysis with combined features achieved higher AUCs than analysis with any feature alone. AUCs estimated for the combined versus highest AUCs among single features were 0.81 (95% confidence interval [CI]: 0.76, 0.86) versus 0.79 (95% CI: 0.73, 0.85) in the full cohort, 0.83 (95% CI: 0.77, 0.92) versus 0.73 (95% CI: 0.61, 0.84) in HR-positive/HER2-negative, 0.88 (95% CI: 0.79, 0.97) versus 0.78 (95% CI: 0.63, 0.89) in HR-positive/HER2-positive, 0.83 (95% CI not available) versus 0.75 (95% CI: 0.46, 0.81) in HR-negative/HER2-positive, and 0.82 (95% CI: 0.74, 0.91) versus 0.75 (95% CI: 0.64, 0.83) in triple negatives. Multi-feature MRI analysis improved pCR prediction over analysis of any individual feature that we examined. Additionally, the improvements in prediction were more notable when analysis was conducted according to cancer subtype.

Effect of Arrival of Prior Mammograms on Recall Negation for Screening Mammograms Performed With Digital Breast Tomosynthesis in a Clinical Setting.

PURPOSE: This retrospective study evaluates the effect of comparison with prior mammograms on recall negation for screening mammography performed with digital breast tomosynthesis (DBT) in a clinical setting and compares it with that performed without DBT. METHODS: This is an Institutional Review Board-approved, HIPAA-compliant retrospective review of the electronic medical record for all nonbaseline screening mammograms performed in clinical practice over 13 months. For each mammogram, we recorded if DBT were used, the BI-RADS assigned at initial interpretation, and whether prior mammograms were available at initial interpretation. If prior mammograms arrived later for comparison, the final BI-RADS assigned after comparison was recorded. A mammogram assigned a BI-RADS 0 at initial interpretation and assigned a BI-RADS 1 or BI-RADS 2 after prior mammograms arrived for comparison was labeled as a recall that was negated by the arrival of prior mammograms. The number of recalls negated for mammograms that used DBT was compared with that for mammograms that did not use DBT. RESULTS: Arrival of prior mammograms for comparison negated the need for recall for mammograms performed with DBT by 67.67% and negated the need for recall for mammograms performed without DBT by 55.80%. After adjusting for age, density, and time between mammograms, the percentage of recalls negated by comparison with prior mammograms was not significantly different for mammograms performed with DBT than it was for those performed without DBT. CONCLUSION: Comparison with prior mammograms remains important for the minimization of recall rates during the use of DBT for screening mammography in the clinical setting.

Breast Cancers Found with Digital Breast Tomosynthesis: A Comparison of Pathology and Histologic Grade.

To compare the pathology and histologic grading of breast cancers detected with digital breast tomosynthesis to those found with conventional digital mammography. The institutional review board approved this study. A database search for all breast cancers diagnosed from June 2012 through December 2013 was performed. Imaging records for these cancers were reviewed and patients who had screening mammography with tomosynthesis as their initial examination were selected. Five dedicated breast imaging radiologists reviewed each of these screening mammograms to determine whether the cancer was visible on conventional digital mammography or whether tomosynthesis was needed to identify the cancer. A cancer was considered mammographically occult if all five radiologists agreed that the cancer could not be seen on conventional digital mammography. The size, pathology and histologic grading for all diagnosed breast cancers were then reviewed. The Mann-Whitney U and Fisher exact tests were utilized to determine any association between imaging findings and cancer size, pathologic type and histologic grade. Sixty-five cancers in 63 patients were identified. Ten of these cancers were considered occult on conventional digital mammography and detected with the addition of tomosynthesis. These mammographically occult cancers were significantly associated with Nottingham grade 1 histologic pathology (p = 0.02), were smaller (median size: 6 mm versus 10 mm, p = 0.07) and none demonstrated axillary nodal metastases. Breast cancers identified through the addition of tomosynthesis are associated with Nottingham grade 1 histologic pathology and prognostically more favorable than cancers identified with conventional digital mammography alone.

Digital Breast Tomosynthesis Utilization in the United States: A Survey of Physician Members of the Society of Breast Imaging.

PURPOSE: To assess utilization of digital breast tomosynthesis (DBT) and examine criteria for offering DBT to patients. METHODS: We created an online survey for physician members of the Society of Breast Imaging to assess their use of DBT. The questions covered availability of DBT at the participant's practice, whether DBT was used for clinical care or research, clinical decision rules guiding patient selection for DBT, costs associated with DBT, plans to obtain DBT, and breast imaging practice characteristics. Fisher's exact tests and logistic regression were used to compare DBT users and nonusers. RESULTS: In all, 670 members responded (response rate = 37%). Of these, 200 (30.0%) respondents reported using DBT, with 89% of these using DBT clinically. Participants were more likely to report DBT use if they worked at an academic practice (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.41 to 3.03; P < .001), a practice with more than 3 breast imagers (OR, 2.36; 95% CI, 1.62 to 3.43; P < .001), or a practice with 7 or more mammography units (OR, 3.05; 95% CI, 2.11 to 4.39; P < .001). Criteria used to select patients to undergo DBT varied, with 107 (68.2%) using exam type (screening versus diagnostic), 25 (15.9%) using mammographic density, and 25 (15.9%) using breast cancer risk. Fees for DBT ranged from $25 to $250. In addition, 62.3% of nonusers planned to obtain DBT. CONCLUSION: DBT is becoming more common but remains a limited resource. Clinical guidelines would assist practices in deciding whether to adopt DBT and in standardizing which patients should receive DBT.

Direct Interactive Public Education by Breast Radiologists About Screening Mammography: Impact on Anxiety and Empowerment.

PURPOSE: Anxiety has been called a "harm" of screening mammography. The authors provided direct, interactive education to lay audiences and measured these sessions' impact on anxiety and any increased understanding of breast cancer screening. METHODS: Academic breast radiologist provided seven 1-hour sessions of structured lectures and question-and-answer periods. Lay language and radiologic images were used to discuss disease background, screening guidelines, and areas of debate. One hundred seventeen participants (mean age, 45 ± 15 years) completed voluntary, anonymous, institutional review board-approved pre and postsession questionnaires relaying their attitudes regarding screening and the impact of the sessions. Results are summarized descriptively. RESULTS: Mean reported anxiety regarding screening (on a scale ranging from 1-5; 1 = no anxiety) was 2.5 ± 1.3. Anxiety was attributed to unknown results (56.4%), anticipation of pain (21.8%), known risk factors (14.5%), general uncertainty (12.7%), waiting for results (9.1%), possibility of more procedures (3.6%), and personal breast cancer history (3.6%). Ninety-seven percent reported that immediate results would lower anxiety (78% of those women indicated a 75%-100% decrease in anxiety); 93% reported that radiologist consultation with images would lower anxiety (75.6% indicated a 75%-100% decrease in anxiety). After the lecture, women reported (on a scale ranging from 1-5) increased understanding of the topic (4.7 ± 0.6), encouragement to screen (4.6 ± 0.7), and reduced anxiety (4.0 ± 1.1). Ninety-seven percent to 100% provided correct responses to these questions: rationale for screening in the absence of family history, recall does not equate to cancer diagnosis, benefit of prior films, and continued importance of physical examination. CONCLUSION: Attendees of radiologist-provided direct public lectures reported decreased anxiety and improved knowledge regarding screening mammography. The resultant reduced anxiety ("harm") and educational empowerment help enable informed decision making and may promote screening attendance.

Compliance With Screening Mammography Guidelines After a False-Positive Mammogram.

PURPOSE: To assess whether women with a false-positive mammogram who do return for screening are less likely to be compliant with screening mammography guidelines than are women with a negative mammogram. METHODS: This institutional review board-approved, HIPAA-compliant retrospective cohort study includes women >40 years old who received 9,385 consecutive, nonbaseline screening mammograms between December 1, 2012 and December 31, 2013. Using linear regression, we evaluated differences in time between mammograms by prior recall status, after adjusting for location of current mammogram (outpatient office versus mobile unit) and age. Using Fisher's exact test, we evaluated the association between compliance with screening guidelines and the recall status on prior mammogram, and compared by location the proportions of noncompliant women who were recalled from prior mammogram. RESULTS: Time between mammograms does not differ based on prior recall status (P = .83). There is no association between compliance with screening mammography guidelines and recall status on prior mammogram (ACR guidelines P = .398, United States Preventive Services Task Force guidelines P = .416). Noncompliant women recalled on prior mammogram are more likely to undergo mammography at the outpatient office rather than the mobile unit (ACR guidelines P = .0004, United States Preventive Services Task Force guidelines P = .0032). CONCLUSIONS: A prior false-positive mammogram is not a significant deterrent to compliance with screening guidelines in those women who return for screening.

Direct Interactive Public Education by Breast Radiologists About Screening Mammography: Impact on Anxiety and Empowerment.

PURPOSE: Anxiety has been called a "harm" of screening mammography. The authors provided direct, interactive education to lay audiences and measured these sessions' impact on anxiety and any increased understanding of breast cancer screening. METHODS: Academic breast radiologist provided seven 1-hour sessions of structured lectures and question-and-answer periods. Lay language and radiologic images were used to discuss disease background, screening guidelines, and areas of debate. One hundred seventeen participants (mean age, 45 ± 15 years) completed voluntary, anonymous, institutional review board-approved pre and postsession questionnaires relaying their attitudes regarding screening and the impact of the sessions. Results are summarized descriptively. RESULTS: Mean reported anxiety regarding screening (on a scale ranging from 1-5; 1 = no anxiety) was 2.5 ± 1.3. Anxiety was attributed to unknown results (56.4%), anticipation of pain (21.8%), known risk factors (14.5%), general uncertainty (12.7%), waiting for results (9.1%), possibility of more procedures (3.6%), and personal breast cancer history (3.6%). Ninety-seven percent reported that immediate results would lower anxiety (78% of those women indicated a 75%-100% decrease in anxiety); 93% reported that radiologist consultation with images would lower anxiety (75.6% indicated a 75%-100% decrease in anxiety). After the lecture, women reported (on a scale ranging from 1-5) increased understanding of the topic (4.7 ± 0.6), encouragement to screen (4.6 ± 0.7), and reduced anxiety (4.0 ± 1.1). Ninety-seven percent to 100% provided correct responses to these questions: rationale for screening in the absence of family history, recall does not equate to cancer diagnosis, benefit of prior films, and continued importance of physical examination. CONCLUSION: Attendees of radiologist-provided direct public lectures reported decreased anxiety and improved knowledge regarding screening mammography. The resultant reduced anxiety ("harm") and educational empowerment help enable informed decision making and may promote screening attendance.

Issues to consider before implementing digital breast tomosynthesis into a breast imaging practice.

OBJECTIVE. The purpose of this article is to discuss issues surrounding the implementation of digital breast tomosynthesis (DBT) into a clinical breast imaging practice and assist radiologists, technologists, and administrators who are considering the addition of this new technology to their practices. CONCLUSION. When appropriate attention is given to image acquisition, interpretation, storage, technologist and radiologist training, patient selection, billing, radiation dose, and marketing, implementation of DBT into a breast imaging practice can be successful.

Implications of CISNET modeling on number needed to screen and mortality reduction with digital mammography in women 40-49 years old.

OBJECTIVE: In this article, we evaluate the implications of recent Cancer Intervention and Surveillance Modeling Network (CISNET) modeling of benefits and harms of screening to women 40-49 years old using annual digital mammography. CONCLUSION: We show that adding annual digital mammography of women 40-49 years old to biennial screening of women 50-74 years old increases lives saved by 27% and life-years gained by 47%. Annual digital mammography in women 40-49 years old saves 42% more lives and life-years than biennial digital mammography. The number needed to screen to save one life (NNS) with annual digital mammography in women 40-49 years old is 588.

Digital breast tomosynthesis utilization in the United States: a survey of physician members of the Society of Breast Imaging.

PURPOSE: To assess utilization of digital breast tomosynthesis (DBT) and examine criteria for offering DBT to patients. METHODS: We created an online survey for physician members of the Society of Breast Imaging to assess their use of DBT. The questions covered availability of DBT at the participant's practice, whether DBT was used for clinical care or research, clinical decision rules guiding patient selection for DBT, costs associated with DBT, plans to obtain DBT, and breast imaging practice characteristics. Fisher's exact tests and logistic regression were used to compare DBT users and nonusers. RESULTS: In all, 670 members responded (response rate = 37%). Of these, 200 (30.0%) respondents reported using DBT, with 89% of these using DBT clinically. Participants were more likely to report DBT use if they worked at an academic practice (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.41 to 3.03; P < .001), a practice with more than 3 breast imagers (OR, 2.36; 95% CI, 1.62 to 3.43; P < .001), or a practice with 7 or more mammography units (OR, 3.05; 95% CI, 2.11 to 4.39; P < .001). Criteria used to select patients to undergo DBT varied, with 107 (68.2%) using exam type (screening versus diagnostic), 25 (15.9%) using mammographic density, and 25 (15.9%) using breast cancer risk. Fees for DBT ranged from $25 to $250. In addition, 62.3% of nonusers planned to obtain DBT. CONCLUSION: DBT is becoming more common but remains a limited resource. Clinical guidelines would assist practices in deciding whether to adopt DBT and in standardizing which patients should receive DBT.

Agreement of the order of overall performance levels under different reading paradigms.

RATIONALE AND OBJECTIVES: To investigate consistency of the orders of performance levels when interpreting mammograms under three different reading paradigms. MATERIALS AND METHODS: We performed a retrospective observer study in which nine experienced radiologists rated an enriched set of mammography examinations that they personally had read in the clinic ("individualized") mixed with a set that none of them had read in the clinic ("common set"). Examinations were interpreted under three different reading paradigms: binary using screening Breast Imaging Reporting and Data System (BI-RADS), receiver-operating characteristic (ROC), and free-response ROC (FROC). The performance in discriminating between cancer and noncancer findings under each of the paradigms was summarized using Youden's index/2+0.5 (Binary), nonparameteric area under the ROC curve (AUC), and an overall FROC index (JAFROC-2). Pearson correlation coefficients were then computed to assess consistency in the ordering of observers' performance levels. Statistical significance of the computed correlation coefficients was assessed using bootstrap confidence intervals obtained by resampling sets of examination-specific observations. RESULTS: All but one of the computed pair-wise correlation coefficients were larger than 0.66 and were significantly different from zero. The correlation between the overall performance measures under the Binary and ROC paradigms was the lowest (0.43) and was not significantly different from zero (95% confidence interval -0.078 to 0.733). CONCLUSION: The use of different evaluation paradigms in the laboratory tends to lead to consistent ordering of the overall performance levels of observers. However, one should recognize that conceptually similar performance indexes resulting from different paradigms often measure different performance characteristics and thus disagreements are not only possible but frequently quite natural.

Binary and multi-category ratings in a laboratory observer performance study: a comparison.

The authors investigated radiologists, performances during retrospective interpretation of screening mammograms when using a binary decision whether to recall a woman for additional procedures or not and compared it with their receiver operating characteristic (ROC) type performance curves using a semi-continuous rating scale. Under an Institutional Review Board approved protocol nine experienced radiologists independently rated an enriched set of 155 examinations that they had not personally read in the clinic, mixed with other enriched sets of examinations that they had individually read in the clinic, using both a screening BI-RADS rating scale (recall/not recall) and a semi-continuous ROC type rating scale (0 to 100). The vertical distance, namely the difference in sensitivity levels at the same specificity levels, between the empirical ROC curve and the binary operating point were computed for each reader. The vertical distance averaged over all readers was used to assess the proximity of the performance levels under the binary and ROC-type rating scale. There does not appear to be any systematic tendency of the readers towards a better performance when using either of the two rating approaches, namely four readers performed better using the semi-continuous rating scale, four readers performed better with the binary scale, and one reader had the point exactly on the empirical ROC curve. Only one of the nine readers had a binary "operating point" that was statistically distant from the same reader's empirical ROC curve. Reader-specific differences ranged from -0.046 to 0.128 with an average width of the corresponding 95% confidence intervals of 0.2 and p-values ranging for individual readers from 0.050 to 0.966. On average, radiologists performed similarly when using the two rating scales in that the average distance between the run in individual reader's binary operating point and their ROC curve was close to zero. The 95% confidence interval for the fixed-reader average (0.016) was (-0.0206, 0.0631) (two-sided p-value 0.35). In conclusion the authors found that in retrospective observer performance studies the use of a binary response or a semi-continuous rating scale led to consistent results in terms of performance as measured by sensitivity-specificity operating points.

The "laboratory" effect: comparing radiologists' performance and variability during prospective clinical and laboratory mammography interpretations.

PURPOSE: To compare radiologists' performance during interpretation of screening mammograms in the clinic with their performance when reading the same mammograms in a retrospective laboratory study. MATERIALS AND METHODS: This study was conducted under an institutional review board-approved, HIPAA-compliant protocol; the need for informed consent was waived. Nine experienced radiologists rated an enriched set of mammograms that they had personally read in the clinic (the "reader-specific" set) mixed with an enriched "common" set of mammograms that none of the participants had previously read in the clinic by using a screening Breast Imaging Reporting and Data System (BI-RADS) rating scale. The original clinical recommendations to recall the women for a diagnostic work-up, for both reader-specific and common sets, were compared with their recommendations during the retrospective experiment. The results are presented in terms of reader-specific and group-averaged sensitivity and specificity levels and the dispersion (spread) of reader-specific performance estimates. RESULTS: On average, the radiologists' performance was significantly better in the clinic than in the laboratory (P = .035). Interreader dispersion of the computed performance levels was significantly lower during the clinical interpretations (P < .01). CONCLUSION: Retrospective laboratory experiments may not represent either expected performance levels or interreader variability during clinical interpretations of the same set of mammograms in the clinical environment well.

A method to improve visual similarity of breast masses for an interactive computer-aided diagnosis environment.

The purpose of this study was to develop and test a method for selecting "visually similar" regions of interest depicting breast masses from a reference library to be used in an interactive computer-aided diagnosis (CAD) environment. A reference library including 1000 malignant mass regions and 2000 benign and CAD-generated false-positive regions was established. When a suspicious mass region is identified, the scheme segments the region and searches for similar regions from the reference library using a multifeature based k-nearest neighbor (KNN) algorithm. To improve selection of reference images, we added an interactive step. All actual masses in the reference library were subjectively rated on a scale from 1 to 9 as to their "visual margins speculations". When an observer identifies a suspected mass region during a case interpretation he/she first rates the margins and the computerized search is then limited only to regions rated as having similar levels of spiculation (within +/-1 scale difference). In an observer preference study including 85 test regions, two sets of the six "similar" reference regions selected by the KNN with and without the interactive step were displayed side by side with each test region. Four radiologists and five nonclinician observers selected the more appropriate ("similar") reference set in a two alternative forced choice preference experiment. All four radiologists and five nonclinician observers preferred the sets of regions selected by the interactive method with an average frequency of 76.8% and 74.6%, respectively. The overall preference for the interactive method was highly significant (p < 0.001). The study demonstrated that a simple interactive approach that includes subjectively perceived ratings of one feature alone namely, a rating of margin "spiculation," could substantially improve the selection of "visually similar" reference images.

Head-mounted versus remote eye tracking of radiologists searching for breast cancer: a comparison.

PURPOSE: We compared performance and visual search parameters of radiologists detecting masses on mammograms by using both a head-mounted (HDMT) and a remote (REM) eye tracker. MATERIALS AND METHODS: Five experienced radiologists read twice a case set of 20 one-view (medial-lateral oblique) mammograms, of which 12 contained a malignant mass and eight were lesion-free. For each observer, one trial used an HDMT eye-tracking system and the other used an REM system. Trials were separated on average by 2 months. Time to hit the location of the mass, dwell, and number of fixations in the location of the mass were measured. The same parameters were measured on a per-trial basis to determine whether there were memory effects from the previous trial. RESULTS: Dwell times in the location of true-positive, false-positive, and false-negative results were significantly shorter (P < .05) using the HDMT (median, 0.395 seconds) than REM (median, 0.482 seconds) systems, but the number of fixations in the location of the response was smaller using the REM system (median, 4.33 versus 5.0 for the HDMT). The observed differences did not seem to be caused by a memory effect. In addition, the relative lack of head mobility using the REM system caused observers to report neck strain. CONCLUSION: Overall, radiologists' visual search behavior was very similar using both types of eye-tracking device. However, because the REM system did not contain a magnetic head tracker, radiologists were allowed very limited head movements when using it, which made them uncomfortable during the experiment.

Effects of lesion conspicuity on visual search in mammogram reading.

RATIONALE AND OBJECTIVES: The goal of mammography screening is to detect breast cancer at early stages, but because of the complexity of the breast parenchyma and the variability of signs of the disease, many cancers go unreported when initially visible on the mammogram. We compared the visual search strategy used by experienced mammographers in a case set where they examined both the mammogram in which a malignant mass was discovered at screening mammography and the most recent prior mammogram. MATERIALS AND METHODS: Four experienced mammographers participated in this experiment. They read a case set of 20 two-view mammograms, of which 15 contained a malignant mass and 5 were lesion-free, in two trials. For each of the cancer cases, two versions were shown to the observers: the one in which the cancer was reported in the clinical practice, called the "current" mammograms, and the most recent prior. Each trial had a balanced mix of current and prior mammograms. In addition, the same set of lesion-free cases was shown to the observers in both trials. The eye movements of the observers were tracked, and visual search parameters such as time to hit the location of the malignant mass, dwell, and mean pupil size in the location of the cancer were collected. Statistical analyses were used to determine whether there were differences between the current and prior mammograms. RESULTS: A total of 66% of the malignant masses in the current mammograms and 57% in the priors attracted some amount of visual attention. From these, 71% yielded a report on the current mammograms, but only 40% on the priors. In the cases where the observer saw the malignant mass, they did so within 2 seconds of image display, regardless of whether the mammogram was current or prior. CONCLUSION: Most unreported malignant masses attracted some amount of visual attention, but it was in the processing of the information extracted in the location of the lesion that most errors occurred. In our experiment, approximately 70% of the total time used by the observers for visual scan of the cases was spent gathering information to corroborate the hypothesis already formed by the radiologist.

Is maximum positive predictive value a good indicator of an optimal screening mammography practice?

OBJECTIVE: Positive predictive value (PPV1) has been used as one important indicator of the quality of screening mammography programs. We show how the relationship between sensitivity and recall rate may affect the operating point at which optimal (maximum) PPV1 occurs. CONCLUSION: Optimal (maximum) PPV1 can occur at any sensitivity level and should not be used as the sole indicator for practice optimization because it does not take into account the number of cancers that would be missed at that sensitivity.