Dose length product to effective dose coefficients in children.

BACKGROUND: The most accurate method for estimating effective dose (the most widely understood metric for tracking patient radiation exposure) from computed tomography (CT) requires time-intensive Monte Carlo simulation. A simpler method multiplies a scalar coefficient by the widely available scanner-reported dose length product (DLP) to estimate effective dose. OBJECTIVE: Develop pediatric effective dose coefficients and assess their agreement with Monte Carlo simulation. MATERIALS AND METHODS: Multicenter, population-based sample of 128,397 pediatric diagnostic CT scans prospectively assembled in 2015-2020 from the University of California San Francisco International CT Dose Registry and the University of Florida library of highly realistic hybrid computational phantoms. We generated effective dose coefficients for seven body regions, stratified by patient age, diameter, and scanner manufacturer. We applied the new coefficients to DLPs to calculate effective doses and assessed their correlations with Monte Carlo radiation transport-generated effective doses. RESULTS: The reported effective dose coefficients, generally higher than previous studies, varied by body region and decreased in magnitude with increasing age. Coefficients were approximately 4 to 13-fold higher (across body regions) for patients <1 year old compared with patients 15-21 years old. For example, head CT (54% of scans) dose coefficients decreased from 0.039 to 0.003 mSv/mGy-cm in patients <1 year old vs. 15-21 years old. There were minimal differences by manufacturer. Using age-based conversion coefficients to estimate effective dose produced moderate to strong correlations with Monte Carlo results (Pearson correlations 0.52-0.80 across body regions). CONCLUSIONS: New pediatric effective dose coefficients update existing literature and can be used to easily estimate effective dose using scanner-reported DLP.

Strategies for Dose Optimization: Views From Health Care Systems.

BACKGROUND: Advances in CT have facilitated widespread use of medical imaging while increasing patient lifetime exposure to ionizing radiation. PURPOSE: To describe dose optimization strategies used by health care organizations to optimize radiation dose and image quality. MATERIALS AND METHODS: A qualitative study of semistructured interviews conducted with 26 leaders from 19 health care systems in the United States, Europe, and Japan. Interviews focused on strategies that were used to optimize radiation dose at the organizational level. A directed content analysis approach was used in data analysis. RESULTS: Analysis identified seven organizational strategies used by these leaders for optimizing CT dose: (1) engaging radiologists and technologists, (2) establishing a CT dose committee, (3) managing organizational change, (4) providing leadership and support, (5) monitoring and benchmarking, (6) modifying CT protocols, and (7) changes in equipment and work rules. CONCLUSIONS: Leaders in these health systems engaged in specific strategies to optimize CT dose within their organizations. The strategies address challenges health systems encounter in optimizing CT dose at the organizational level and offer an evolving framework for consideration in dose optimization efforts for enhancing safety and use of medical imaging.

Association of the Intensity of Diagnostic Evaluation With Outcomes in Incidentally Detected Lung Nodules.

Importance: Whether guideline-concordant lung nodule evaluations lead to better outcomes remains unknown. Objective: To examine the association between the intensity of lung nodule diagnostic evaluations and outcomes, safety, and health expenditures. Design, Setting, and Participants: This comparative effectiveness research study analyzed health plan enrollees at Kaiser Permanente Washington in Seattle, Washington, and Marshfield Clinic in Marshfield, Wisconsin, with an incidental lung nodule detected between January 1, 2005, and December 31, 2015. Included patients were 35 years or older, had no high suspicion of infection, had no history of malignant neoplasm, and had no evidence of advanced lung cancer on nodule detection. Data analysis was conducted from January 7 to August 19, 2020. Exposures: With the 2005 Fleischner Society guidelines (selected for their applicability to the time frame under investigation) as the comparator, 2 other intensities of lung nodule evaluation were defined. Guideline-concordant evaluation followed the guidelines. Less intensive evaluation was the absence of recommended testing, longer-than-recommended surveillance intervals, or less invasive testing than recommended. More intensive evaluation consisted of testing when the guidelines recommended no further testing, shorter-than-recommended surveillance intervals, or more invasive testing than recommended. Main Outcomes and Measures: The main outcome was the proportion of patients with lung cancer who had stage III or IV disease, radiation exposure, procedure-related adverse events, and health expenditures 2 years after nodule detection. Results: Among the 5057 individuals included in this comparative effectiveness research study, 1925 (38%) received guideline-concordant, 1863 (37%) less intensive, and 1269 (25%) more intensive diagnostic evaluations. The entire cohort comprised 2786 female patients (55%), and the mean (SD) age was 67 (13) years. Adjusted analyses showed that compared with guideline-concordant evaluations, less intensive evaluations were associated with fewer procedure-related adverse events (risk difference [RD], -5.9%; 95% CI, -7.2% to -4.6%), lower mean radiation exposure (-9.5 milliSieverts [mSv]; 95% CI, -10.3 mSv to -8.7 mSv), and lower mean health expenditures (-$10 916; 95% CI, -$16 112 to -$5719); no difference in stage III or IV disease was found among patients diagnosed with lung cancer (RD, 4.6%; 95% CI, -22% to +31%). More intensive evaluations were associated with more procedure-related adverse events (RD, +8.1%; 95% CI, +5.6% to +11%), higher mean radiation exposure (+6.8 mSv; 95% CI, +5.8 mSv to +7.8 mSv), and higher mean health expenditures ($20 132; 95% CI, +$14 398 to +$25 868); no difference in stage III or IV disease was observed (RD, -0.5%; 95% CI, -28% to +27%). Conclusions and Relevance: This study found inconclusive evidence of an association between less intensive diagnostic evaluations and more advanced stage at lung cancer diagnosis compared with guideline-concordant care; higher intensities of diagnostic evaluations were associated with greater procedural complications, radiation exposure, and expenditures. These findings underscore the need for more evidence on better ways to evaluate lung nodules and to avoid unnecessarily intensive diagnostic evaluations of lung nodules.

A Scalable Database of Organ Doses for Common Diagnostic Fluoroscopy Procedures of Children: Procedures of Historical Practice for Use in Radiation Epidemiology Studies.

Assessment of health effects from low-dose radiation exposures in patients undergoing diagnostic imaging is an active area of research. High-quality dosimetry information pertaining to these medical exposures is generally not readily available to clinicians or epidemiologists studying radiation-related health risks. The purpose of this study was to provide methods for organ dose estimation in pediatric patients undergoing four common diagnostic fluoroscopy procedures: the upper gastrointestinal (UGI) series, the lower gastrointestinal (LGI) series, the voiding cystourethrogram (VCUG) and the modified barium swallow (MBS). Abstracted X-ray film data and physician interviews were combined to generate procedure outlines detailing X-ray beam projections, imaged anatomy, length of X-ray exposure, and presence and amount of contrast within imaged anatomy. Monte Carlo radiation transport simulations were completed for each of the four diagnostic fluoroscopy procedures across the 162-member (87 males and 75 females) University of Florida/National Cancer Institute pediatric phantom library, which covers variations in both subject height and weight. Absorbed doses to 28 organs, including the active marrow and bone endosteum, were assigned for all 162 phantoms by procedure. Additionally, we provide dose coefficients (DCs) in a series of supplementary tables. The DCs give organ doses normalized to procedure-specific dose metrics, including: air kerma-area product (µGy/mGy · cm2), air kerma at the reference point (µGy/µGy), number of spot films (SF) (µGy/number of SFs) and total fluoroscopy time (µGy/s). Organs accumulating the highest absorbed doses per procedure were as follows: kidneys between 0.9-25.4 mGy, 1.1-16.6 mGy and 1.1-9.7 mGy for the UGI, LGI and VCUG procedures, respectively, and salivary glands between 0.2-3.7 mGy for the MBS procedure. Average values of detriment-weighted dose, a phantom-specific surrogate for the effective dose based on ICRP Publication 103 tissue-weighting factors, were 0.98 mSv, 1.16 mSv, 0.83 mSv and 0.15 mSv for the UGI, LGI, VCUG and MBS procedures, respectively. Scalable database of organ dose coefficients by patient sex, height and weight, and by procedure exposure time, reference point air kerma, kerma-area product or number of spot films, allows clinicians and researchers to compute organ absorbed doses based on their institution-specific and patient-specific dose metrics. In addition to informing on patient dosimetry, this work has the potential to facilitate exposure assessments in epidemiological studies designed to investigate radiation-related risks.

Comparison of the Harms, Advantages, and Costs Associated With Alternative Guidelines for the Evaluation of Hematuria.

IMPORTANCE: Existing recommendations for the diagnostic testing of hematuria range from uniform evaluation of varying intensity to patient-level risk stratification. Concerns have been raised about not only the costs and advantages of computed tomography (CT) scans but also the potential harms of CT radiation exposure. OBJECTIVE: To compare the advantages, harms, and costs associated with 5 guidelines for hematuria evaluation. DESIGN, SETTING, AND PARTICIPANTS: A microsimulation model was developed to assess each of the following guidelines (listed in order of increasing intensity) for initial evaluation of hematuria: Dutch, Canadian Urological Association (CUA), Kaiser Permanente (KP), Hematuria Risk Index (HRI), and American Urological Association (AUA). Participants comprised a hypothetical cohort of patients (n = 100 000) with hematuria aged 35 years or older. This study was conducted from August 2017 through November 2018. EXPOSURES: Under the Dutch and CUA guidelines, patients received cystoscopy and ultrasonography if they were 50 years or older (Dutch) or 40 years or older (CUA). Under the KP and HRI guidelines, patients received different combinations of cystoscopy, ultrasonography, and CT urography or no evaluation on the basis of risk factors. Under the AUA guidelines, all patients 35 years or older received cystoscopy and CT urography. MAIN OUTCOMES AND MEASURES: Urinary tract cancer detection rates, radiation-induced secondary cancers (from CT radiation exposure), procedural complications, false-positive rates per 100 000 patients, and incremental cost per additional urinary tract cancer detected. RESULTS: The simulated cohort included 100 000 patients with hematuria, aged 35 years or older. A total of 3514 patients had urinary tract cancers (estimated prevalence, 3.5%; 95% CI, 3.0%-4.0%). The AUA guidelines missed detection for the fewest number of cancers (82 [2.3%]) compared with the detection rate of the HRI (116 [3.3%]) and KP (130 [3.7%]) guidelines. However, the simulation model projected 108 (95% CI, 34-201) radiation-induced cancers under the KP guidelines, 136 (95% CI, 62-229) under the HRI guidelines, and 575 (95% CI, 184-1069) under the AUA guidelines per 100 000 patients. The CUA and Dutch guidelines missed detection for a larger number of cancers (172 [4.9%] and 251 [7.1%]) but had 0 radiation-induced secondary cancers. The AUA guidelines cost approximately double the other 4 guidelines ($939/person vs $443/person for Dutch guidelines), with an incremental cost of $1 034 374 per urinary tract cancer detected compared with that of the HRI guidelines. CONCLUSIONS AND RELEVANCE: In this simulation study, uniform CT imaging for patients with hematuria was associated with increased costs and harms of secondary cancers, procedural complications, and false positives, with only a marginal increase in cancer detection. Risk stratification may optimize the balance of advantages, harms, and costs of CT.

Cost Analysis of the STONE Randomized Trial: Can Health Care Costs be Reduced One Test at a Time?

BACKGROUND: Decreasing the use of high-cost tests may reduce health care costs. OBJECTIVE: To compare costs of care for patients presenting to the emergency department (ED) with suspected kidney stones randomized to 1 of 3 initial imaging tests. RESEARCH DESIGN: Patients were randomized to point-of-care ultrasound (POC US, least costly), radiology ultrasound (RAD US), or computed tomography (CT, most costly). Subsequent testing and treatment were the choice of the treating physician. SUBJECTS: A total of 2759 patients at 15 EDs were randomized to POC US (n=908), RAD US, (n=893), or CT (n=958). Mean age was 40.4 years; 51.8% were male. MEASURES: All medical care documented in the trial database in the 7 days following enrollment was abstracted and coded to estimate costs using national average 2012 Medicare reimbursements. Costs for initial ED care and total 7-day costs were compared using nonparametric bootstrap to account for clustering of patients within medical centers. RESULTS: Initial ED visit costs were modestly lower for patients assigned to RAD US: $423 ($411, $434) compared with patients assigned to CT: $448 ($438, $459) (P<0.0001). Total costs were not significantly different between groups: $1014 ($912, $1129) for POC US, $970 ($878, $1078) for RAD US, and $959 ($870, $1044) for CT. Hospital admissions contributed over 50% of total costs, though only 11% of patients were admitted. Mean total costs (and admission rates) varied substantially by site from $749 to $1239. CONCLUSIONS: Assignment to a less costly test had no impact on overall health care costs for ED patients. System-level interventions addressing variation in admission rates from the ED might have greater impact on costs.

Validation of a Medicare Claims-based Algorithm for Identifying Breast Cancers Detected at Screening Mammography.

BACKGROUND: The breast cancer detection rate is a benchmark measure of screening mammography quality, but its computation requires linkage of mammography interpretive performance information with cancer incidence data. A Medicare claims-based measure of detected breast cancers could simplify measurement of this benchmark and facilitate mammography quality assessment and research. OBJECTIVES: To validate a claims-based algorithm that can identify with high positive predictive value (PPV) incident breast cancers that were detected at screening mammography. RESEARCH DESIGN: Development of a claims-derived algorithm using classification and regression tree analyses within a random half-sample of Medicare screening mammography claims followed by validation of the algorithm in the remaining half-sample using clinical data on mammography results and cancer incidence from the Breast Cancer Surveillance Consortium (BCSC). SUBJECTS: Female fee-for-service Medicare enrollees aged 68 years and older who underwent screening mammography from 2001 to 2005 within BCSC registries in 4 states (CA, NC, NH, and VT), enabling linkage of claims and BCSC mammography data (N=233,044 mammograms obtained by 104,997 women). MEASURES: Sensitivity, specificity, and PPV of algorithmic identification of incident breast cancers that were detected by radiologists relative to a reference standard based on BCSC mammography and cancer incidence data. RESULTS: An algorithm based on subsequent codes for breast cancer diagnoses and treatments and follow-up mammography identified incident screen-detected breast cancers with 92.9% sensitivity [95% confidence interval (CI), 91.0%-94.8%], 99.9% specificity (95% CI, 99.9%-99.9%), and a PPV of 88.0% (95% CI, 85.7%-90.4%). CONCLUSIONS: A simple claims-based algorithm can accurately identify incident breast cancers detected at screening mammography among Medicare enrollees. The algorithm may enable mammography quality assessment using Medicare claims alone.

Calculation of Organ Doses for a Large Number of Patients Undergoing CT Examinations.

OBJECTIVE: The objective of our study was to develop an automated calculation method to provide organ dose assessment for a large cohort of pediatric and adult patients undergoing CT examinations. MATERIALS AND METHODS: We adopted two dose libraries that were previously published: the volume CT dose index-normalized organ dose library and the tube current-exposure time product (100 mAs)-normalized weighted CT dose index library. We developed an algorithm to calculate organ doses using the two dose libraries and the CT parameters available from DICOM data. We calculated organ doses for pediatric (n = 2499) and adult (n = 2043) CT examinations randomly selected from four health care systems in the United States and compared the adult organ doses with the values calculated from the ImPACT calculator. RESULTS: The median brain dose was 20 mGy (pediatric) and 24 mGy (adult), and the brain dose was greater than 40 mGy for 11% (pediatric) and 18% (adult) of the head CT studies. Both the National Cancer Institute (NCI) and ImPACT methods provided similar organ doses (median discrepancy < 20%) for all organs except the organs located close to the scanning boundaries. The visual comparisons of scanning coverage and phantom anatomies revealed that the NCI method, which is based on realistic computational phantoms, provides more accurate organ doses than the ImPACT method. CONCLUSION: The automated organ dose calculation method developed in this study reduces the time needed to calculate doses for a large number of patients. We have successfully used this method for a variety of CT-related studies including retrospective epidemiologic studies and CT dose trend analysis studies.

Classification accuracy of claims-based methods for identifying providers failing to meet performance targets.

Quality assessment is critical for healthcare reform, but data sources are lacking for measurement of many important healthcare outcomes. With over 49 million people covered by Medicare as of 2010, Medicare claims data offer a potentially valuable source that could be used in targeted health care quality improvement efforts. However, little is known about the operating characteristics of provider profiling methods using claims-based outcome measures that may estimate provider performance with error. Motivated by the example of screening mammography performance, we compared approaches to identifying providers failing to meet guideline targets using Medicare claims data. We used data from the Breast Cancer Surveillance Consortium and linked Medicare claims to compare claims-based and clinical estimates of cancer detection rate. We then demonstrated the performance of claim-based estimates across a broad range of operating characteristics using simulation studies. We found that identification of poor performing providers was extremely sensitive to algorithm specificity, with no approach identifying more than 65% of poor performing providers when claims-based measures had specificity of 0.995 or less. We conclude that claims have the potential to contribute important information on healthcare outcomes to quality improvement efforts. However, to achieve this potential, development of highly accurate claims-based outcome measures should remain a priority.

Study of Tomography Of Nephrolithiasis Evaluation (STONE): methodology, approach and rationale.

BACKGROUND: Urolithiasis (kidney stones) is a common reason for Emergency Department (ED) visits, accounting for nearly 1% of all visits in the United States. Computed tomography (CT) has become the most common imaging test for these patients but there are few comparative effectiveness data to support its use in comparison to ultrasound. This paper describes the rationale and methods of STONE (Study of Tomography Of Nephrolithiasis Evaluation), a pragmatic randomized comparative effectiveness trial comparing different imaging strategies for patients with suspected urolithiasis. METHODS: STONE is a multi-center, non-blinded pragmatic randomized comparative effectiveness trial of patients between ages 18 and 75 with suspected nephrolithiasis seen in an ED setting. Patients were randomized to one of three initial imaging examinations: point-of-care ultrasound, ultrasound performed by a radiologist or CT. Participants then received diagnosis and treatment per usual care. The primary aim is to compare the rate of severe SAEs (Serious Adverse Events) between the three arms. In addition, a broad range of secondary outcomes was assessed at baseline and regularly for six months post-baseline using phone, email and mail questionnaires. RESULTS: Excluding 17 patients who withdrew after randomization, a total of 2759 patients were randomized and completed a baseline questionnaire (n=908, 893 and 958 in the point-of-care ultrasound, radiology ultrasound and radiology CT arms, respectively). Follow-up is complete, and full or partial outcomes were assessed on over 90% of participants. CONCLUSIONS: The detailed methodology of STONE will provide a roadmap for comparative effectiveness studies of diagnostic imaging conducted in an ED setting.

Distinguishing screening from diagnostic mammograms using Medicare claims data.

BACKGROUND: Medicare claims data may be a fruitful data source for research or quality measurement in mammography. However, it is uncertain whether claims data can accurately distinguish screening from diagnostic mammograms, particularly when claims are not linked with cancer registry data. OBJECTIVES: To validate claims-based algorithms that can identify screening mammograms with high positive predictive value (PPV) in claims data with and without cancer registry linkage. RESEARCH DESIGN: Development of claims-derived algorithms using classification and regression tree analyses within a random half-sample of bilateral mammogram claims with validation in the remaining half-sample. SUBJECTS: Female fee-for-service Medicare enrollees aged 66 years and older, who underwent bilateral mammography from 1999 to 2005 within Breast Cancer Surveillance Consortium (BCSC) registries in 4 states (CA, NC, NH, and VT), enabling linkage of claims and BCSC mammography data (N=383,730 mammograms obtained from 146,346 women). MEASURES: Sensitivity, specificity, and PPV of algorithmic designation of a "screening" purpose of the mammogram using a BCSC-derived reference standard. RESULTS: In claims data without cancer registry linkage, a 3-step claims-derived algorithm identified screening mammograms with 97.1% sensitivity, 69.4% specificity, and a PPV of 94.9%. In claims that are linked to cancer registry data, a similar 3-step algorithm had higher sensitivity (99.7%), similar specificity (62.7%), and higher PPV (97.4%). CONCLUSIONS: Simple algorithms can identify Medicare claims for screening mammography with high predictive values in Medicare claims alone and in claims linked with cancer registry data.

Use of diagnostic imaging studies and associated radiation exposure for patients enrolled in large integrated health care systems, 1996-2010.

CONTEXT: Use of diagnostic imaging has increased significantly within fee-for-service models of care. Little is known about patterns of imaging among members of integrated health care systems. OBJECTIVE: To estimate trends in imaging utilization and associated radiation exposure among members of integrated health care systems. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of electronic records of members of 6 large integrated health systems from different regions of the United States. Review of medical records allowed direct estimation of radiation exposure from selected tests. Between 1 million and 2 million member-patients were included each year from 1996 to 2010. MAIN OUTCOME MEASURE: Advanced diagnostic imaging rates and cumulative annual radiation exposure from medical imaging. RESULTS: During the 15-year study period, enrollees underwent a total of 30.9 million imaging examinations (25.8 million person-years), reflecting 1.18 tests (95% CI, 1.17-1.19) per person per year, of which 35% were for advanced diagnostic imaging (computed tomography [CT], magnetic resonance imaging [MRI], nuclear medicine, and ultrasound). Use of advanced diagnostic imaging increased from 1996 to 2010; CT examinations increased from 52 per 1000 enrollees in 1996 to 149 per 1000 in 2010, 7.8% annual increase (95% CI, 5.8%-9.8%); MRI use increased from 17 to 65 per 1000 enrollees, 10% annual growth (95% CI, 3.3%-16.5%); and ultrasound rates increased from 134 to 230 per 1000 enrollees, 3.9% annual growth (95% CI, 3.0%-4.9%). Although nuclear medicine use decreased from 32 to 21 per 1000 enrollees, 3% annual decline (95% CI, 7.7% decline to 1.3% increase), PET imaging rates increased after 2004 from 0.24 to 3.6 per 1000 enrollees, 57% annual growth. Although imaging use increased within all health systems, the adoption of different modalities for anatomic area assessment varied. Increased use of CT between 1996 and 2010 resulted in increased radiation exposure for enrollees, with a doubling in the mean per capita effective dose (1.2 mSv vs 2.3 mSv) and the proportion of enrollees who received high (>20-50 mSv) exposure (1.2% vs 2.5%) and very high (>50 mSv) annual radiation exposure (0.6% vs 1.4%). By 2010, 6.8% of enrollees who underwent imaging received high annual radiation exposure (>20-50 mSv) and 3.9% received very high annual exposure (>50 mSv). CONCLUSION: Within integrated health care systems, there was a large increase in the rate of advanced diagnostic imaging and associated radiation exposure between 1996 and 2010.

External validation of Medicare claims codes for digital mammography and computer-aided detection.

BACKGROUND: While Medicare claims are a potential resource for clinical mammography research or quality monitoring, the validity of key data elements remains uncertain. Claims codes for digital mammography and computer-aided detection (CAD), for example, have not been validated against a credible external reference standard. METHODS: We matched Medicare mammography claims for women who received bilateral mammograms from 2003 to 2006 to corresponding mammography data from the Breast Cancer Surveillance Consortium (BCSC) registries in four U.S. states (N = 253,727 mammograms received by 120,709 women). We assessed the accuracy of the claims-based classifications of bilateral mammograms as either digital versus film and CAD versus non-CAD relative to a reference standard derived from BCSC data. RESULTS: Claims data correctly classified the large majority of film and digital mammograms (97.2% and 97.3%, respectively), yielding excellent agreement beyond chance (κ = 0.90). Claims data correctly classified the large majority of CAD mammograms (96.6%) but a lower percentage of non-CAD mammograms (86.7%). Agreement beyond chance remained high for CAD classification (κ = 0.83). From 2003 to 2006, the predictive values of claims-based digital and CAD classifications increased as the sample prevalences of each technology increased. CONCLUSION: Medicare claims data can accurately distinguish film and digital bilateral mammograms and mammograms conducted with and without CAD. IMPACT: The validity of Medicare claims data regarding film versus digital mammography and CAD suggests that these data elements can be useful in research and quality improvement.

Environmental causes of breast cancer and radiation from medical imaging: findings from the Institute of Medicine report.

Susan G. Komen for the Cure asked the Institute of Medicine (IOM) to perform a comprehensive review of environmental causes and risk factors for breast cancer. Interestingly, none of the consumer products (ie, bisphenol A, phthalates), industrial chemicals (ie, benzene, ethylene oxide), or pesticides (ie, DDT/DDE) considered could be conclusively linked to an increased risk of breast cancer, although the IOM acknowledged that the available evidence was insufficient to draw firm conclusions for many of these exposures, calling for more research in these areas. The IOM found sufficient evidence to conclude that the 2 environmental factors most strongly associated with breast cancer were exposure to ionizing radiation and to combined postmenopausal hormone therapy. The IOM's conclusion of a causal relation between radiation exposure and cancer is consistent with a large and varied literature showing that exposure to radiation in the same range as used for computed tomography will increase the risk of cancer. It is the responsibility of individual health care providers who order medical imaging to understand and weigh the risk of any medical procedures against the expected benefit.

Facility characteristics do not explain higher false-positive rates in diagnostic mammography at facilities serving vulnerable women.

BACKGROUND: Facilities serving vulnerable women have higher false-positive rates for diagnostic mammography than facilities serving nonvulnerable women. False positives lead to anxiety, unnecessary biopsies, and higher costs. OBJECTIVE: Examine whether availability of on-site breast ultrasound or biopsy services, academic medical center affiliation, or profit status explains differences in false-positive rates. DESIGN: We examined 78,733 diagnostic mammograms performed to evaluate breast problems at Breast Cancer Surveillance Consortium facilities from 1999 to 2005. We used logistic-normal mixed effects regression to determine if adjusting for facility characteristics accounts for observed differences in false-positive rates. MEASURES: Facilities were characterized as serving vulnerable women based on the proportion of mammograms performed on racial/ethnic minorities, women with lower educational attainment, limited household income, or rural residence. RESULTS: Although the availability of on-site ultrasound and biopsy services was associated with greater odds of a false positive in most models [odds ratios (OR) ranging from 1.24 to 1.88; P<0.05], adjustment for these services did not attenuate the association between vulnerability and false-positive rates. Estimated ORs for the effect of vulnerability indexes on false-positive rates unadjusted for facility services were: lower educational attainment [OR 1.33; 95% confidence intervals (CI), 1.03-1.74]; racial/ethnic minority status (OR 1.33; 95% CI, 0.98-1.80); rural residence (OR 1.56; 95% CI, 1.26-1.92); limited household income (OR 1.38; 95% CI, 1.10-1.73). After adjustment, estimates remained relatively unchanged. CONCLUSIONS: On-site diagnostic service availability may contribute to unnecessary biopsies, but does not explain the higher diagnostic mammography false-positive rates at facilities serving vulnerable women.

Radiation-related cancer risks from CT colonography screening: a risk-benefit analysis.

OBJECTIVE: The purpose of this study was to estimate the ratio of cancers prevented to induced (benefit-risk ratio) for CT colonography (CTC) screening every 5 years from the age of 50 to 80 years. MATERIALS AND METHODS: Radiation-related cancer risk was estimated using risk projection models based on the National Research Council's Biological Effects of Ionizing Radiation (BEIR) VII Committee's report and screening protocols from the American College of Radiology Imaging Network's National CT Colonography Trial. Uncertainty intervals were estimated using Monte Carlo simulation methods. Comparative modeling with three colorectal cancer microsimulation models was used to estimate the potential reduction in colorectal cancer cases and deaths. RESULTS: The estimated mean effective dose per CTC screening study was 8 mSv for women and 7 mSv for men. The estimated number of radiation-related cancers resulting from CTC screening every 5 years from the age of 50 to 80 years was 150 cases/100,000 individuals screened (95% uncertainty interval, 80-280) for men and women. The estimated number of colorectal cancers prevented by CTC every 5 years from age 50 to 80 ranged across the three microsimulation models from 3580 to 5190 cases/100,000 individuals screened, yielding a benefit-risk ratio that varied from 24:1 (95% uncertainty interval, 13:1-45:1) to 35:1 (19:1-65:1). The benefit-risk ratio for cancer deaths was even higher than the ratio for cancer cases. Inclusion of radiation-related cancer risks from CT examinations performed to follow up extracolonic findings did not materially alter the results. CONCLUSION: Concerns have been raised about recommending CTC as a routine screening tool because of potential harms including the radiation risks. Based on these models, the benefits from CTC screening every 5 years from the age of 50 to 80 years clearly outweigh the radiation risks.

Diagnostic imaging rates for head injury in the ED and states' medical malpractice tort reforms.

OBJECTIVE: Physicians' fears of being sued may lead to defensive medical practices, such as ordering nonindicated medical imaging. We investigated the association between states' medical malpractice tort reforms and neurologic imaging rates for patients seen in the emergency department with mild head trauma. METHODS: We assessed neurologic imaging among a national sample of 8588 women residing in 10 US states evaluated in an emergency setting for head injury between January 1, 1992, and December 31, 2001. We assessed the odds of imaging as it varied by the enactment of medical liability reform laws. RESULTS: The medical liability reform laws were significantly associated with the likelihood of imaging. States with laws that limited monetary damages (odds ratio [OR], 0.63; 95% confidence interval [CI], 0.40-0.99), mandated periodic award payments (OR, 0.64; 95% CI, 0.43-0.97), or specified collateral source offset rules (OR, 0.62; 95% CI, 0.40-0.96) had an approximately 40% lower odds of imaging, whereas states that had laws that limited attorney's contingency fees had significantly higher odds of imaging (OR, 1.5; 95% CI, 0.99-2.4), compared to states without these laws. When we used a summation of the number of laws in place, the greater the number of laws, the lower the odds of imaging. In the multivariate analysis, after adjusting for individual and community factors, the total number of laws remained significantly associated with the odds of imaging, and the effect of the individual laws was attenuated, but not eliminated. CONCLUSION: The tort reforms we examined were associated with the propensity to obtain neurologic imaging. If these results are confirmed in larger studies, tort reform might mitigate defensive medical practices.

Rising use of diagnostic medical imaging in a large integrated health system.

Little has been published characterizing specific patterns of the dramatic rise in diagnostic imaging during the past decade. In a large health plan, 377,048 patients underwent 4.9 million diagnostic tests from 1997 through 2006. Cross-sectional imaging nearly doubled over those years, rising from 260 to 478 examinations per thousand enrollees per year. Imaging with computed tomography (CT) doubled, and imaging with magnetic resonance imaging (MRI) tripled. Cross-sectional studies added to existing studies instead of replacing them, and the annual per enrollee cost of radiology imaging more than doubled. The dramatic rise in imaging raises both costs and radiation exposure.

Factors associated with mammography utilization: a systematic quantitative review of the literature.

OBJECTIVE: A significant segment of women remains underscreened with mammography. We sought to summarize literature related to factors associated with receipt of mammography. For data sources, we used English language papers published between 1988 and 2007, including 221 studies describing 4,957,347 women. METHODS: We calculated odds ratios (ORs) associated with receipt of mammography. Random effects modeling was used to assess trends in mammography utilization and to calculate summary multivariate point estimates. Results were stratified by age, race/ethnicity, and study year. We summarized results between 1988 and 2004 and compared recent years with these results. RESULTS: Physician access barriers, such as not having a physician-recommend mammography (adjusted OR 0.16, 95% CI 0.08-0.33) and having no primary care provider (OR 0.41, 95% CI 0.32-0.53), were highly predictive of not obtaining mammography. Past screening behavior correlated strongly with receipt of mammography (clinical breast examination, adjusted OR 9.15, 95% CI 3.49-23.98) and Pap test (adjusted OR 3.45, 95% CI 2.12-5.62). With the exception of having no insurance (adjusted OR 0.47, 95% CI 0.39-0.57), several potential socioeconomic barriers did not appear to have an important impact on screening. Racial and ethnic differences were seen. Concerns about cost, mammography safety, and pain were more important to African American and Latina women, and having no insurance was more important to white and Chinese women. Cost concerns and the presence of a family history of breast cancer were less important to older women, whereas screening knowledge had a stronger impact on mammography use in women aged > or =65 years. When we compared study results before 2004 with those later, we found very little difference in the multivariate, adjusted ORs over time. CONCLUSIONS: Women with poor access to physicians are much less likely to undergo mammography. Improving the frequency and scope of mammography recommendation by primary care providers is the single most important direct contribution the medical community can make toward increasing mammography use.