Performance benchmarks for diagnostic mammography

PURPOSE: To evaluate a range of performance parameters pertinent to the comprehensive auditing of diagnostic mammography examinations, and to derive performance benchmarks therefrom, by pooling data collected from large numbers of patients and radiologists that are likely to be representative of mammography practice in the United States. MATERIALS AND METHODS: Institutional review board approval was met, informed consent was not required, and this study was Health Insurance Portability and Accountability Act compliant. Six mammography registries contributed data to the Breast Cancer Surveillance Consortium (BCSC), providing patient demographic and clinical information, mammogram interpretation data, and biopsy results from defined population-based catchment areas. The study involved 151 mammography facilities and 646 interpreting radiologists. The study population included women 18 years of age or older who underwent at least one diagnostic mammography examination between 1996 and 2001. Collected data were used to derive mean performance parameter values, including abnormal interpretation rate, positive predictive value (for abnormal interpretation, biopsy recommended, and biopsy performed), cancer diagnosis rate, invasive cancer size, and the percentages of minimal cancers, axillary node-negative invasive cancers, and stage 0 and I cancers. Additional benchmarks were derived for these performance parameters, including 10th, 25th, 50th (median), 75th, and 90th percentile values. RESULTS: The study involved 332,926 diagnostic mammography examinations. Mean performance parameter values were abnormal interpretation rate, 8.0%; positive predictive value for abnormal interpretation, 31.4%; positive predictive value for biopsy recommended, 31.5%; positive predictive value for biopsy performed, 39.5%; cancer diagnosis rate, 25.3 per 1000 examinations; invasive cancer size, 20.2 mm; percentage of minimal cancers, 42.0%; percentage of axillary node-negative invasive cancers, 73.6%; and percentage of stage 0 and I cancers, 62.4%. CONCLUSION: The presented BCSC outcomes data and performance benchmarks may be used by mammography facilities and individual radiologists to evaluate their own performance for diagnostic mammography as determined by means of periodic comprehensive audits.     

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 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.     

Automated management of screening and diagnostic mammography

We designed an automated system for managing large-scale screening and diagnostic mammography. The system collects coded mammographic findings from the radiologist and records a history directly from the patient. This information is stored in an integrated clinical data base to which the results of subsequent examinations or surgery are added. In addition, the system generates letters to the patient and her physician that describe mammographic findings and letters reminding them of routine screening visits. For patients who have positive results on examinations, it checks for records of biopsy or repeat mammography and generates follow-up letters if appropriate intervention is not found. While this system is part of a comprehensive computerized hospital information system, mammography management tools with most of the features described can be designed for relatively inexpensive microcomputers.     

Auditing and benchmarks in screening and diagnostic mammography

Radiologists can use outcome data such as cancer size and stage to determine how well their own practice provides benefit to their patients and can use measures such as screening recall rates and positive predictive values to assess how well adverse consequences are being contained. New data on national benchmarks for screening and diagnostic mammography in the United States allow radiologists to evaluate their own performance with respect to their peers. This article discusses recommended outcome values in the United States and Europe, current Mammography Quality Standards Act audit requirements, and Institute of Medicine proposals for future requirements.     

Clinical outcome assessment in mammography: an audit of 7,506 screening and diagnostic mammography examinations

PURPOSE: To perform an audit of our routine mammographic practice and to compare our results to performance benchmarks. MATERIALS AND METHODS: We analyzed the outcomes of 7,506 consecutive examinations performed in 1 year. Screening and diagnostic cases were evaluated separately and mammographic assessments were based on the Breast Imaging Reporting and Data System (BI-RADS) classification. RESULTS: In 6,858 (91%) screening and 648 (9%) diagnostic cases, outcomes varied substantially. The recall rate was 10.9%. Estimated sensitivity and specificity were similar (100% vs. 98% and 88% vs. 94%) in the screening and diagnostic groups. Positive predictive values (PPV1, PPV2, and PPV3) were higher in the diagnostic group compared to the screening group (64%, 65%, and 68% vs. 4.9%, 33%, and 39%, respectively). Cancer outcomes in the screening and diagnostic groups were, respectively, as follows: cancer detection rate, 6.1 per thousand vs. 86.4 per thousand; mean invasive cancer size, 15.7 mm vs. 24.5 mm; minimal cancers, 38% vs. 19%; stage 0-1 cancers, 50% vs. 21%; and lymph node negativity, 76% vs. 29%. CONCLUSION: The measures of our screening outcomes were concordant with the literature and the performance benchmarks for screening mammography; however, in our diagnostic group, the reasons for the higher PPV, higher cancer detection rate, and the diagnosis of cancer in a more advanced stage compared to the performance benchmarks should be investigated with more detailed periodic audits.     

Breast tomosynthesis: A diagnostic addition to screening digital mammography

Objectives

Comparison between digital mammography alone and with adding digital breast tomosynthesis in breast cancer screening.

Nuclear medicine for general radiologists: endocrinological examinations

We reviewed nuclear endocrinological examinations of the thyroid, parathyroid, and adrenal glands that are clinically performed in Japan as well as somatostatin receptor imaging, which is widely used in Europe, the United States, and other countries. 123I thyroid scintigraphy is especially useful in detecting ectopic goiters and differentiating between Basedow's disease and subacute thyroiditis or Plummer's disease, all of which exhibit thyrotoxicosis. 201Tl is useful to detect foci metastasized from well differentiated thyroid cancer and to differentiate malignant from benign tumors. 67Ga-citrate is an agent used for patients suspected of having malignant lymphoma or undifferentiated carcinoma of the thyroid. Radioiodinated MIBG is a specific agent for medullary thyroid carcinoma. 99mTc-MIBI is a good agent for locating hyperfunctioning parathyroid tissues. 131I-adosterol is useful to locate the lesions of primary aldosteronism, Cushing's syndrome, adrenogenital syndrome, and select adenomas among incidental tumors. Radioiodinated MIBG scintigraphy has high diagnostic accuracy in locating pheochromocytomas and neuroblastomas. 111In-labeled octreotide is useful in locating, hormone-producing gastrointestinal and pancreatic tumors including carcinoids, gastrinomas, and insulinomas. Radiolabeled somatostatin receptor analogs are used not only to locate but also to treat malignant somatostatin receptor-positive tumors. We hope that Octreoscan will be available in Japan in the near future.     

Tumor markers: essential diagnostic tools for radiologists]

A tumor marker is defined as a substance that is produced by the body in response to cancer or by the cancer tissue itself. Since discovery of the Bence-Jones protein in 1848 and AFP (alpha-fetoprotein), CEA (carcino-embryonic antigen), and SCC (squamous cell carcinoma antigen) in the 1960s and 1970s, a number of tumor markers have been developed for routine clinical laboratory tests. Some tumor markers are specific for one type of cancer, while others are positive for several cancer types. Furthermore, tumor markers are seen in non-cancerous conditions as well as in cancer. A positive result for one tumor marker does not necessarily indicate the presence of a malignant lesion. Because of insufficient sensitivity and specificity, most tumor markers cannot be used in screening for cancer in the early stage. When the presence of cancer is suspected, it must be confirmed using other diagnostic approaches such as radiological tests, pathological tests, or meticulous observation of disease progress. Tumor markers are useful in the follow-up of patients after treatment for malignant lesions, and they are usually superior to radiological tests in detecting recurrent lesions. When cancer is evaluated radiologically, knowledge of tumor markers is of great help to radiologists. Basic knowledge regarding tumor markers and pitfalls in their clinical usage are described.     

Medical audit of diagnostic mammography examinations: comparison with screening outcomes obtained concurrently

OBJECTIVE: We performed a medical audit of our diagnostic mammography practice and compared clinical outcomes with those of screening mammography examinations performed concurrently. MATERIALS AND METHODS: We analyzed 46,857 consecutive mammography examinations (10,007 diagnostic, 36,850 screening) from 1997 to 2000, including data on demographics, image interpretation, and biopsy (including size, nodal status, and cancer stage). RESULTS: The mean age at diagnostic mammography was 55.8 years (mean age at screening mammogram, 59.1 years; p < 0.0001). Among patients who underwent diagnostic examinations, 14.7% had a strong or very strong family history of breast cancer (screening, 11.6%; p < 0.0001). Examination findings were interpreted as abnormal in 14.4% (screening, 5.2%; p < 0.0001). Biopsy was performed in 11.9% (screening, 1.4%; p < 0.0001). Forty-six percent of the biopsies were positive for malignancy (screening, 38%; p < 0.0001). The cancer detection rate was 55 per 1000 (screening, 5/1000; p < 0.0001). Of cancers found, 74.4% were stage 0 or I (screening, 89.3%; p < 0.0001), average size was 18.0 mm (screening, 12.9 mm; p < 0.0001), and axillary nodes were positive for malignancy in 19.9% of invasive cancers (screening, 6.3; p < 0.0001). Differences between diagnostic and screening outcomes were attributable predominantly to the subgroup of diagnostic examinations performed for evaluation of palpable masses. CONCLUSION: Medical auditing of diagnostic mammography examinations yields substantially different results compared with those of screening examinations, including different patient demographics; higher number of positive biopsies; higher cancer detection rates; and larger, more advanced-stage cancers. Diagnostic and screening data should be segregated during auditing, or if this is not possible, analysis of combined results should be based on known differences between diagnostic and screening outcomes.     

Improving the adherence of urban women to mammography guidelines: strategies for radiologists

Only 16% of women over 40 years of age are being screened regularly with mammography. To learn what radiologists and technologists can do to increase patient adherence to the screening guidelines of the American Cancer Society, especially by poor, urban women, the authors surveyed patients at a county facility immediately after mammography to document the patients' experiences with technologists and the procedure. Analysis of these data led to the conclusion that the radiologist should encourage an expanded role for the technologist as a breast health educator. By incorporating the use of a well-designed patient brochure, technologists can greatly enhance their effectiveness by decreasing the patient's anxiety and increasing her understanding of the procedure and of the importance of screening. Radiologists need to appreciate the potential of an expanded technologist's role for increasing future referrals.     

Nanotechnology development and utilization: a primer for diagnostic and interventional radiologists

The term nanotechnology refers to the design, creation, and manipulation of structures on the nanometer scale. Much of the ongoing research and development of nanotechnology is focused on the development of novel methods of imaging and delivery of therapeutics through minimally invasive means. Multifunctional nanoparticles offer great promise for molecular imaging and directing novel therapeutics to molecular targets, which was never before possible. Nanoparticle-based contrast agents have been developed for all imaging modalities. A rapidly increasing number of companies and government funding initiatives have led to a large number of novel agents in various stages of development, ranging from in vitro and in vivo animal studies to clinical use. However, barriers to the delivery of nanoparticles for tumor imaging and therapy exist. Interventional radiologists may circumvent these barriers by using imaging to guide delivery of nanoparticles.     

Interpreting data from audits when screening and diagnostic mammography outcomes are combined

OBJECTIVE: The objective of this study was to use mathematic models to aid mammography practices in interpreting outcomes data derived from a combination of screening and diagnostic examinations, and in interpreting diagnostic mammography outcomes data that are not segregated by indication for examination. MATERIALS AND METHODS: We analyzed outcomes from 51,805 consecutive mammography examinations. Screening and diagnostic examinations were audited separately. Diagnostic examinations were audited by indication for examination. Extrapolating from our known mix of screening (79%) and diagnostic (21%) examinations, we determined expected combined outcomes for various mixes that might be encountered in clinical practice. Similarly, we determined the expected overall diagnostic mammography outcomes for various clinically relevant mixes of indications for examination. RESULTS: Outcomes vary substantially depending on the mix of screening and diagnostic examinations performed. For example, expected outcomes for practices with screening-diagnostic mixes of 90-10% and 50-50% are, respectively: rate of abnormal findings, 6% versus 11%; rate of positive biopsy findings, 38% versus 42%; cancer detection rate, 10 per 1,000 versus 30 per 1,000; mean invasive cancer size, 14.4 mm versus 16.0 mm; nodal metastasis rate, 8% versus 11%; and rate of stage 0 and stage I cancers, 87% versus 82%. Diagnostic outcomes also vary substantially according to indication for examination, with a higher rate of abnormal findings, a higher rate of positive biopsy findings, and a larger mean invasive cancer size expected for mixes involving a high percentage of workups for palpable lesions. CONCLUSION: When screening and diagnostic mammography outcomes are not segregated during auditing, and when diagnostic outcomes are not segregated by indication for examination, analysis of combined audit data should be based on extrapolations from known outcomes.     

Computer-aided detection for screening mammography

Mammographic film reading is a highly demanding task, particularly in screening programs where the reader must perform a detailed visual search of a large number of images for signs of abnormality that are often subtle or small, and which occur very infrequently. False-negative cases, in which signs of abnormality are missed by a film reader, are known to occur. Computer-aided detection (CAD) systems, which automatically detect potential abnormalities and indicate their locations to the reader, have the capacity to reduce the frequency of such errors by ensuring that all suspicious regions of the images are thoroughly searched and by increasing the weighting attached to subtle signs that may otherwise have been dismissed. CAD systems depend on suites of detection algorithms, but each algorithm has a different sensitivity and specificity and the effect of prompting errors on human performance with CAD is complex. This article is a brief review of CAD for screening mammography; it highlights both the strengths and the weaknesses of the approach, and describes some of the methodologies used to evaluate CAD in a clinical setting.     

The supply of and requirements for diagnostic and therapeutic radiologists

This report summarizes the findings of a national study to examine the future requirements for and supply of radiologists. By 1990, there is expected to be a moderate shortage of the therapeutic radiologists, coupled with a substantial oversupply of diagnostic radiologists.