Co-registered spectral photoacoustic tomography and ultrasonography of breast cancer

Many breast cancer patients receive neoadjuvant treatment to reduce tumor size and enable breast conserving therapy. Most imaging methods used to monitor response to neoadjuvant chemotherapy or hormone therapy depend on overall gross tumor morphology and size measurements, which may not be sensitive or specific, despite tumor response on a cellular level. A more sensitive and specific method of detecting response to therapy might allow earlier adjustments in treatment, and thus result in better outcomes while avoiding unnecessary morbidity. We developed an imaging system that combines spectral photoacoustic tomography and ultrasonography to predict breast neoadjuvant therapeutic response based on blood volume and blood oxygenation contrast. The system consists of a tunable dye laser pumped by a Nd:YAG laser, a commercial ultrasound imaging system (Philips iU22), and a multichannel data acquisition system which displays co-registered photoacoustic and ultrasound images in real time. Early studies demonstrate functional imaging capabilities, such as oxygen saturation and total concentration of hemoglobin, in addition to ultrasonography of tumor morphology. Further study is needed to determine if the co-registered photoacoustic tomography and ultrasonography system may provide an accurate tool to assess treatment efficacy by monitoring tumor response in vivo

Effect of Radiologists’ Diagnostic Work-up Volume on Interpretive Performance

We found that radiologists with a higher annual volume of work-ups for recalled screening mammograms they initially interpreted had consistently higher screening sensitivity and cancer detection rates; however, these performance improvements were accompanied by higher false-positive rates

Establishing a Gold Standard for Test Sets. Variation in Interpretive Agreement of Expert Mammographers

Test sets for assessing and improving radiologic image interpretation have been used for decades and typically evaluate performance relative to gold-standard interpretations by experts. To assess test sets for screening mammography, a gold-standard for whether a woman should be recalled for additional work-up is needed, given that interval cancers may be occult on mammography and some findings ultimately determined to be benign require additional imaging to determine if biopsy is warranted. Using experts to set a gold-standard assumes little variation occurs in their interpretations, but this has not been explicitly studied in mammography

Educational Interventions to Improve Screening Mammography Interpretation: A Randomized Controlled Trial

Conduct a randomized controlled trial of educational interventions to improve performance of screening mammography interpretation

Criteria for identifying radiologists with acceptable screening mammography interpretive performance on basis of multiple performance measures.

ObjectiveUsing a combination of performance measures, we updated previously proposed criteria for identifying physicians whose performance interpreting screening mammography may indicate suboptimal interpretation skills.Materials and methodsIn this study, six expert breast imagers used a method based on the Angoff approach to update criteria for acceptable mammography performance on the basis of two sets of combined performance measures: set 1, sensitivity and specificity for facilities with complete capture of false-negative cancers; and set 2, cancer detection rate (CDR), recall rate, and positive predictive value of a recall (PPV1) for facilities that cannot capture false-negative cancers but have reliable cancer follow-up information for positive mammography results. Decisions were informed by normative data from the Breast Cancer Surveillance Consortium (BCSC).ResultsUpdated combined ranges for acceptable sensitivity and specificity of screening mammography are sensitivity≥80% and specificity≥85% or sensitivity 75-79% and specificity 88-97%. Updated ranges for CDR, recall rate, and PPV1 are: CDR≥6 per 1000, recall rate 3-20%, and any PPV1; CDR 4-6 per 1000, recall rate 3-15%, and PPV1≥3%; or CDR 2.5-4.0 per 1000, recall rate 5-12%, and PPV1 3-8%. Using the original criteria, 51% of BCSC radiologists had acceptable sensitivity and specificity; 40% had acceptable CDR, recall rate, and PPV1. Using the combined criteria, 69% had acceptable sensitivity and specificity and 62% had acceptable CDR, recall rate, and PPV1.ConclusionThe combined criteria improve previous criteria by considering the interrelationships of multiple performance measures and broaden the acceptable performance ranges compared with previous criteria based on individual measures

Diagnostic Mammography: Identifying Minimally Acceptable Interpretive Performance Criteria

PurposeTo develop criteria to identify thresholds for the minimally acceptable performance of physicians interpreting diagnostic mammography studies.Materials and methodsIn an institutional review board-approved HIPAA-compliant study, an Angoff approach was used to set criteria for identifying minimally acceptable interpretive performance for both workup after abnormal screening examinations and workup of a breast lump. Normative data from the Breast Cancer Surveillance Consortium (BCSC) was used to help the expert radiologist identify the impact of cut points. Simulations, also using data from the BCSC, were used to estimate the expected clinical impact from the recommended performance thresholds.ResultsFinal cut points for workup of abnormal screening examinations were as follows: sensitivity, less than 80%; specificity, less than 80% or greater than 95%; abnormal interpretation rate, less than 8% or greater than 25%; positive predictive value (PPV) of biopsy recommendation (PPV2), less than 15% or greater than 40%; PPV of biopsy performed (PPV3), less than 20% or greater than 45%; and cancer diagnosis rate, less than 20 per 1000 interpretations. Final cut points for workup of a breast lump were as follows: sensitivity, less than 85%; specificity, less than 83% or greater than 95%; abnormal interpretation rate, less than 10% or greater than 25%; PPV2, less than 25% or greater than 50%; PPV3, less than 30% or greater than 55%; and cancer diagnosis rate, less than 40 per 1000 interpretations. If underperforming physicians moved into the acceptable range after remedial training, the expected result would be (a) diagnosis of an additional 86 cancers per 100,000 women undergoing workup after screening examinations, with a reduction in the number of false-positive examinations by 1067 per 100,000 women undergoing this workup, and (b) diagnosis of an additional 335 cancers per 100,000 women undergoing workup of a breast lump, with a reduction in the number of false-positive examinations by 634 per 100,000 women undergoing this workup.ConclusionInterpreting physicians who fall outside one or more of the identified cut points should be reviewed in the context of an overall assessment of all their performance measures and their specific practice setting to determine if remedial training is indicated

Correlation Between Screening Mammography Interpretive Performance on a Test Set and Performance in Clinical Practice.

Rationale and objectivesEvidence is inconsistent about whether radiologists' interpretive performance on a screening mammography test set reflects their performance in clinical practice. This study aimed to estimate the correlation between test set and clinical performance and determine if the correlation is influenced by cancer prevalence or lesion difficulty in the test set.Materials and methodsThis institutional review board-approved study randomized 83 radiologists from six Breast Cancer Surveillance Consortium registries to assess one of four test sets of 109 screening mammograms each; 48 radiologists completed a fifth test set of 110 mammograms 2 years later. Test sets differed in number of cancer cases and difficulty of lesion detection. Test set sensitivity and specificity were estimated using woman-level and breast-level recall with cancer status and expert opinion as gold standards. Clinical performance was estimated using women-level recall with cancer status as the gold standard. Spearman rank correlations between test set and clinical performance with 95% confidence intervals (CI) were estimated.ResultsFor test sets with fewer cancers (N = 15) that were more difficult to detect, correlations were weak to moderate for sensitivity (woman level = 0.46, 95% CI = 0.16, 0.69; breast level = 0.35, 95% CI = 0.03, 0.61) and weak for specificity (0.24, 95% CI = 0.01, 0.45) relative to expert recall. Correlations for test sets with more cancers (N = 30) were close to 0 and not statistically significant.ConclusionsCorrelations between screening performance on a test set and performance in clinical practice are not strong. Test set performance more accurately reflects performance in clinical practice if cancer prevalence is low and lesions are challenging to detect

Diagnostic Mammography: Identifying Minimally Acceptable Interpretive Performance Criteria

PURPOSE: To develop criteria to identify thresholds for the minimally acceptable performance of physicians interpreting diagnostic mammography studies. MATERIALS AND METHODS: In an institutional review board–approved HIPAA–compliant study, an Angoff approach was used to set criteria for identifying minimally acceptable interpretive performance for both workup after abnormal screening examinations and workup of a breast lump. Normative data from the Breast Cancer Surveillance Consortium (BCSC) was used to help the expert radiologist identify the impact of cut points. Simulations, also using data from the BCSC, were used to estimate the expected clinical impact from the recommended performance thresholds. RESULTS: Final cut points for workup of abnormal screening examinations were as follows: sensitivity, less than 80%; specificity, less than 80% or greater than 95%; abnormal interpretation rate, less than 8% or greater than 25%; positive predictive value (PPV) of biopsy recommendation (PPV(2)), less than 15% or greater than 40%; PPV of biopsy performed (PPV(3)), less than 20% or greater than 45%; and cancer diagnosis rate, less than 20 per 1000 interpretations. Final cut points for workup of a breast lump were as follows: sensitivity, less than 85%; specificity, less than 83% or greater than 95%; abnormal interpretation rate, less than 10% or greater than 25%; PPV(2), less than 25% or greater than 50%; PPV(3), less than 30% or greater than 55%; and cancer diagnosis rate, less than 40 per 1000 interpretations. If underperforming physicians moved into the acceptable range after remedial training, the expected result would be (a) diagnosis of an additional 86 cancers per 100 000 women undergoing workup after screening examinations, with a reduction in the number of false-positive examinations by 1067 per 100 000 women undergoing this workup, and (b) diagnosis of an additional 335 cancers per 100 000 women undergoing workup of a breast lump, with a reduction in the number of false-positive examinations by 634 per 100 000 women undergoing this workup. CONCLUSION: Interpreting physicians who fall outside one or more of the identified cut points should be reviewed in the context of an overall assessment of all their performance measures and their specific practice setting to determine if remedial training is indicated. © RSNA, 201