Improving the Safety of Computed Tomography Through Automated Quality Measurement: A Radiologist Reader Study of Radiation Dose, Image Noise, and Image Quality.

OBJECTIVES: The Centers for Medicare and Medicaid Services funded the development of a computed tomography (CT) quality measure for use in pay-for-performance programs, which balances automated assessments of radiation dose with image quality to incentivize dose reduction without compromising the diagnostic utility of the tests. However, no existing quantitative method for assessing CT image quality has been validated against radiologists' image quality assessments on a large number of CT examinations. Thus to develop an automated measure of image quality, we tested the relationship between radiologists' subjective ratings of image quality with measurements of radiation dose and image noise. MATERIALS AND METHODS: Board-certified, posttraining, clinically active radiologists rated the image quality of 200 diagnostic CT examinations from a set of 734, representing 14 CT categories. Examinations with significant distractions, motion, or artifact were excluded. Radiologists rated diagnostic image quality as excellent, adequate, marginally acceptable, or poor; the latter 2 were considered unacceptable for rendering diagnoses. We quantified the relationship between ratings and image noise and radiation dose, by category, by analyzing the odds of an acceptable rating per standard deviation (SD) increase in noise or geometric SD (gSD) in dose. RESULTS: One hundred twenty-five radiologists contributed 24,800 ratings. Most (89%) were acceptable. The odds of an examination being rated acceptable statistically significantly increased per gSD increase in dose and decreased per SD increase in noise for most categories, including routine dose head, chest, and abdomen-pelvis, which together comprise 60% of examinations performed in routine practice. For routine dose abdomen-pelvis, the most common category, each gSD increase in dose raised the odds of an acceptable rating (2.33; 95% confidence interval, 1.98-3.24), whereas each SD increase in noise decreased the odds (0.90; 0.79-0.99). For only 2 CT categories, high-dose head and neck/cervical spine, neither dose nor noise was associated with ratings. CONCLUSIONS: Radiation dose and image noise correlate with radiologists' image quality assessments for most CT categories, making them suitable as automated metrics in quality programs incentivizing reduction of excessive radiation doses.

Large variation in radiation dose for routine abdomen CT: reasons for excess and easy tips for reduction.

OBJECTIVE: To characterize the use and impact of radiation dose reduction techniques in actual practice for routine abdomen CT. METHODS: We retrospectively analyzed consecutive routine abdomen CT scans in adults from a large dose registry, contributed by 95 hospitals and imaging facilities. Grouping exams into deciles by, first, patient size, and second, size-adjusted dose length product (DLP), we summarized dose and technical parameters and estimated which parameters contributed most to between-protocols dose variation. Lastly, we modeled the total population dose if all protocols with mean size-adjusted DLP above 433 or 645 mGy-cm were reduced to these thresholds. RESULTS: A total of 748,846 CTs were performed using 1033 unique protocols. When sorted by patient size, patients with larger abdominal diameters had increased dose and effective mAs (milliampere seconds), even after adjusting for patient size. When sorted by size-adjusted dose, patients in the highest versus the lowest decile in size-adjusted DLP received 6.4 times the average dose (1680 vs 265 mGy-cm) even though diameter was no different (312 vs 309 mm). Effective mAs was 2.1-fold higher, unadjusted CTDIvol 2.9-fold, and phase 2.5-fold for patients in the highest versus lowest size-adjusted DLP decile. There was virtually no change in kV (kilovolt). Automatic exposure control was widely used to modulate mAs, whereas kV modulation was rare. Phase was the strongest driver of between-protocols variation. Broad adoption of optimized protocols could result in total population dose reductions of 18.6-40%. CONCLUSION: There are large variations in radiation doses for routine abdomen CT unrelated to patient size. Modification of kV and single-phase scanning could result in substantial dose reduction. CLINICAL RELEVANCE: Radiation dose-optimization techniques for routine abdomen CT are routinely under-utilized leading to higher doses than needed. Greater modification of technical parameters and number of phases could result in substantial reduction in radiation exposure to patients. KEY POINTS: • Based on an analysis of 748,846 routine abdomen CT scans in adults, radiation doses varied tremendously across patients of the same size and optimization techniques were routinely under-utilized. • The difference in observed dose was due to variation in technical parameters and phase count. Automatic exposure control was commonly used to modify effective mAs, whereas kV was rarely adjusted for patient size. Routine abdomen CT should be performed using a single phase, yet multi-phase was common. • kV modulation by patient size and restriction to a single phase for routine abdomen indications could result in substantial reduction in radiation doses using well-established dose optimization approaches.

Dose length product to effective dose coefficients in adults.

OBJECTIVES: The most accurate method for estimating patient effective dose (a principal 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. We developed new adult effective dose coefficients using actual patient scans and assessed their agreement with Monte Carlo simulation. METHODS: A multicenter sample of 216,906 adult CT scans was prospectively assembled in 2015-2020 from the University of California San Francisco International CT Dose Registry and the University of Florida library of computational phantoms. We generated effective dose coefficients for eight body regions, stratified by patient sex, diameter, and scanner manufacturer. We applied the new coefficients to DLPs to calculate effective doses and assess their correlations with Monte Carlo radiation transport-generated effective dose. RESULTS: Effective dose coefficients varied by body region and decreased in magnitude with increasing patient diameter. Coefficients were approximately twofold higher for torso scans in smallest compared with largest diameter categories. For example, abdomen and pelvis coefficients decreased from 0.027 to 0.013 mSv/mGy-cm between the 16-20 cm and 41+ cm categories. There were modest but consistent differences by sex and manufacturer. Diameter-based coefficients used to estimate effective dose produced strong correlations with the reference standard (Pearson correlations 0.77-0.86). The reported conversion coefficients differ from previous studies, particularly in neck CT. CONCLUSIONS: New effective dose coefficients derived from empirical clinical scans can be used to easily estimate effective dose using scanner-reported DLP. CLINICAL RELEVANCE STATEMENT: Scalar coefficients multiplied by DLP offer a simple approximation to effective dose, a key radiation dose metric. New effective dose coefficients from this study strongly correlate with gold standard, Monte Carlo-generated effective dose, and differ somewhat from previous studies. KEY POINTS: • Previous effective dose coefficients were derived from theoretical models rather than real patient data. • The new coefficients (from a large registry/phantom library) differ from previous studies. • The new coefficients offer reasonably reliable values for estimating effective dose.

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.

Reference phantom selection in pediatric computed tomography using data from a large, multicenter registry.

BACKGROUND: Radiation dose metrics vary by the calibration reference phantom used to report doses. By convention, 16-cm diameter cylindrical polymethyl-methacyrlate phantoms are used for head imaging and 32-cm diameter phantoms are used for body imaging in adults. Actual usage patterns in children remain under-documented. OBJECTIVE: This study uses the University of California San Francisco International CT Dose Registry to describe phantom selection in children by patient age, body region and scanner manufacturer, and the consequent impact on radiation doses. MATERIALS AND METHODS: For 106,837 pediatric computed tomography (CT) exams collected between Jan. 1, 2015, and Nov. 2, 2020, in children up to 17 years of age from 118 hospitals and imaging facilities, we describe reference phantom use patterns by body region, age and manufacturer, and median and 75th-percentile dose-length product (DLP) and volume CT dose index (CTDIvol) doses when using 16-cm vs. 32-cm phantoms. RESULTS: There was relatively consistent phantom selection by body region. Overall, 98.0% of brain and skull examinations referenced 16-cm phantoms, and 95.7% of chest, 94.4% of abdomen and 100% of cervical-spine examinations referenced 32-cm phantoms. Only GE deviated from this practice, reporting chest and abdomen scans using 16-cm phantoms with some frequency in children up to 10 years of age. DLP and CTDIvol values from 16-cm phantom-referenced scans were 2-3 times higher than 32-cm phantom-referenced scans. CONCLUSION: REFERENCE PHANTOM SELECTION IS HIGHLY CONSISTENT, WITH A SMALL BUT SIGNIFICANT NUMBER OF ABDOMEN AND CHEST SCANS (~5%) USING 16-CM PHANTOMS IN YOUNGER CHILDREN, WHICH PRODUCES DLP VALUES APPROXIMATELY TWICE AS HIGH AS EXAMS REFERENCED TO 32-CM PHANTOMS.

Effect of Present-on-Admission (POA) Reporting Accuracy on Hospital Performance Assessments Using Risk-Adjusted Mortality.

OBJECTIVE: To evaluate how the accuracy of present-on-admission (POA) reporting affects hospital 30-day acute myocardial infarction (AMI) mortality assessments. DATA SOURCES: A total of 2005 California patient discharge data (PDD) and vital statistics death files. STUDY DESIGN: We compared hospital performance rankings using an established model assessing hospital performance for AMI with (1) a model incorporating POA indicators of whether a secondary condition was a comorbidity or a complication of care, and (2) a simulation analysis that factored POA indicator accuracy into the hospital performance assessment. For each simulation, we changed POA indicators for six major acute risk factors of AMI mortality. The probability of POA being changed depended on patient and hospital characteristics. PRINCIPAL FINDINGS: Comparing the performance rankings of 268 hospitals using the established model with that using the POA indicator, 67 hospitals' (25 percent) rank differed by ≥10 percent. POA reporting inaccuracy due to overreporting and underreporting had little additional impact; POA overreporting contributed to 4 percent of hospitals' difference in rank compared to the POA model and POA underreporting contributed to <1 percent difference. CONCLUSION: Incorporating POA indicators into risk-adjusted models of AMI care has a substantial impact on hospital rankings of performance that is not primarily attributable to inaccuracy in POA hospital reporting.

Accuracy of do not resuscitate (DNR) in administrative data.

This article evaluates the accuracy of reporting do not resuscitate (DNR) orders in administrative data for use in risk-adjusted hospital assessments. We compared DNR reporting by 48 California hospitals in 2005 patient discharge data (PDD) with gold-standard assessments made by registered nurses (RNs) who reabstracted 1,673 records of patients with myocardial infarction, pneumonia, or heart failure. The PDD agreed with the RN reabstraction in 1,411 (84.3%) cases. The administrative data did not reflect a DNR order in 71 of 512 records where the RN indicated there was (14% false negative rates), and reflected a DNR order in 191 of 1,161 records where the RN indicated there was not (16% false positive rate). The accuracy of DNR was more problematic for patients who died, suggesting that hospital-reported DNR is problematic for capturing patient preferences for resuscitation that can be used for risk-adjusted outcomes assessments.

Federally qualified health centers and private practice performance on ambulatory care measures.

BACKGROUND: The 2010 Affordable Care Act relies on Federally Qualified Health Centers (FQHCs) and FQHC look-alikes (look-alikes) to provide care for newly insured patients, but ties increased funding to demonstrated quality and efficiency. PURPOSE: To compare FQHC and look-alike physician performance with private practice primary care physicians (PCPs) on ambulatory care quality measures. METHODS: The study was a cross-sectional analysis of visits in the 2006-2008 National Ambulatory Medical Care Survey. Performance of FQHCs and look-alikes on 18 quality measures was compared with private practice PCPs. Data analysis was completed in 2011. RESULTS: Compared to private practice PCPs, FQHCs and look-alikes performed better on six measures (p<0.05); worse on diet counseling in at-risk adolescents (26% vs 36%, p=0.05); and no differently on 11 measures. Higher performance occurred in ACE inhibitors use for congestive heart failure (51% vs 37%, p=0.004); aspirin use in coronary artery disease (CAD; 57% vs 44%, p=0.004); ß-blocker use for CAD (59% vs 47%, p=0.01); no use of benzodiazepines in depression (91% vs 84%, p=0.008); blood pressure screening (90% vs 86%, p<0.001); and screening electrocardiogram (EKG) avoidance in low-risk patients (99% vs 93%, p<0.001). Adjusting for patient characteristics yielded similar results, except that private practice PCPs no longer performed better on any measures. CONCLUSIONS: FQHCs and look-alikes demonstrated equal or better performance than private practice PCPs on select quality measures despite serving patients who have more chronic disease and socioeconomic complexity. These findings can provide policymakers with some reassurance as to the quality of chronic disease and preventive care at Federally Qualified Health Centers and look-alikes, as they plan to use these health centers to serve 20 million newly insured individuals.

The accuracy of present-on-admission reporting in administrative data.

OBJECTIVE: To test the accuracy of reporting present-on-admission (POA) and to assess whether POA reporting accuracy differs by hospital characteristics. DATA SOURCES: We performed an audit of POA reporting of secondary diagnoses in 1,059 medical records from 48 California hospitals. STUDY DESIGN: We used patient discharge data (PDD) to select records with secondary diagnoses that are powerful predictors of mortality and could potentially represent comorbidities or complications among patients who either had a primary procedure of a percutaneous transluminal coronary angioplasty or a primary diagnosis of acute myocardial infarction, community-acquired pneumonia, or congestive heart failure. We modeled the relationship between secondary diagnoses POA reporting accuracy (over-reporting and under-reporting) and hospital characteristics. DATA COLLECTION: We created a gold standard from blind reabstraction of the medical records and compared the accuracy of the PDD against the gold standard. PRINCIPAL FINDINGS: The PDD and gold standard agreed on POA reporting in 74.3 percent of records, with 13.7 percent over-reporting and 11.9 percent under-reporting. For-profit hospitals tended to overcode secondary diagnoses as present on admission (odds ratios [OR] 1.96; 95 percent confidence interval [CI] 1.11, 3.44), whereas teaching hospitals tended to undercode secondary diagnoses as present on admission (OR 2.61; 95 percent CI 1.36, 5.03). CONCLUSIONS: POA reporting of secondary diagnoses is moderately accurate but varies by hospitals. Steps should be taken to improve POA reporting accuracy before using POA in hospital assessments tied to payments.

The relationship between Gulf War illness, brain N-acetylaspartate, and post-traumatic stress disorder.

A previous study (Haley RW, Marshall WW, McDonald GG, Daugherty MA, Petty F, Fleckenstein JL: Brain abnormalities in Gulf War syndrome: evaluation with 1H MR spectroscopy. Radiology 2000; 215: 807-817) suggested that individuals with Gulf War Illness (GWI) had reduced quantities of the neuronal marker N-acetylaspartate (NAA) in the basal ganglia and pons. This study aimed to determine whether NAA is reduced in these regions and to investigate correlations with other possible causes of GWI, such as psychological response to stress in a large cohort of Gulf War veterans. Individuals underwent tests to determine their physical and psychological health and to identify veterans with (n=81) and without (n=97) GWI. When concentrations of NAA and ratios of NAA to creatine- and choline-containing metabolites were measured in the basal ganglia and pons, no significant differences were found between veterans with or without GWI, suggesting that GWI is not associated with reduced NAA in these regions. Veterans with GWI had significantly higher rates of post-traumatic stress disorder, supporting the idea that GWI symptoms are stress related.

Biologic markers determine both the risk and the timing of recurrence in breast cancer.

Breast cancer has a long natural history. Established and emerging biologic markers address overall risk but not necessarily timing of recurrence. 346 adjuvant naïve breast cancer cases from Guy's Hospital with 23 years minimum follow-up and archival blocks were recut and reassessed for hormone-receptors (HR), HER2-receptor and grade. Disease-specific survival (DSS) was analyzed by recursive partitioning. To validate insights from this analysis, gene-signatures (proliferative and HR-negative) were evaluated for their ability to predict early versus late metastatic risk in 683 node-negative, adjuvant naïve breast cancers annotated with expression microarray data. Risk partitioning showed that adjuvant naïve node-negative outcome risk was primarily partitioned by tumor receptor status and grade but not tumor size. HR-positive and HER2-negative (HRpos) risk was partitioned by tumor grade; low grade cases have very low early risk but a 20% fall-off in DSS 10 or more years after diagnosis. Higher grade HRpos cases have risk over >20 years. Triple-negative (Tneg) and HER2-positive (HER2pos) cases DSS events occurred primarily within the first 5 years. Among node-positive cases, only low grade conferred late risk, suggesting that proliferative gene signatures that identify proliferation would be important for predicting early but not late recurrence. Using pooled data from four publicly available data sets for node-negative tumors annotated with gene expression and outcome data, we evaluated four prognostic gene signatures: two proliferation-based and two immune function-based. Tumor proliferative capacity predicted early but not late metastatic risk for HRpos cases. The immune function or HRneg specific signatures predicted only early metastatic risk in Tneg and HER2pos cases. Breast cancer prognostic signatures need to inform both risk and timing of metastatic events and may best be applied within subsets. Current signatures predict for outcome risk within 5 years of diagnosis. Predictors of late risk for HR positive disease are needed.

Choline metabolism, proliferation, and angiogenesis in nonenhancing grades 2 and 3 astrocytoma.

PURPOSE: To study choline metabolism in biopsies from nonenhancing Grade 2 (AS2) and Grade 3 (AS3) astrocytomas to determine whether (1) phosphocholine (PC) dominates in AS3, and (2) PC is associated with proliferation or angiogenesis. PC and glycerophosphocholine (GPC) are involved in phospholipid metabolism that accompanies mitosis. PC is the predominant peak in Grade 4 astrocytoma (GBM) while GPC dominates in AS2. MATERIALS AND METHODS: We used high resolution magic angle spinning magnetic resonance spectroscopy to compare the concentrations of 10 metabolites in 41 biopsies (16 AS2 and 25 AS3) from 24 tumors. Immunohistochemistry was performed on paired biopsies to determine the cell density, Ki-67 proliferation index, and vascular endothelial growth factor (VEGF) angiogenic marker expression. RESULTS: AS3 had higher PC than AS2; however, the PC:GPC was less than 1 in all cases irrespective of tumor grade. Within tumors, GPC increased with Ki-67 and PC and tCho increased with cell density. There was no association between any choline compound and VEGF. CONCLUSION: These data suggest that PC:GPC less than 1 is not unique to low grade glioma. Furthermore, the PC concentration that is a marker of aggressive glial tumors is not tightly linked to cell proliferation or angiogenesis in nonenhancing astrocytomas.

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.

A statistical method (cross-validation) for bone loss region detection after spaceflight.

Astronauts experience bone loss after the long spaceflight missions. Identifying specific regions that undergo the greatest losses (e.g. the proximal femur) could reveal information about the processes of bone loss in disuse and disease. Methods for detecting such regions, however, remains an open problem. This paper focuses on statistical methods to detect such regions. We perform statistical parametric mapping to get t-maps of changes in images, and propose a new cross-validation method to select an optimum suprathreshold for forming clusters of pixels. Once these candidate clusters are formed, we use permutation testing of longitudinal labels to derive significant changes.

Diagnostic value of PET/CT for the staging and restaging of pediatric tumors.

OBJECTIVE: The objective of this retrospective study was to compare the diagnostic value of 2-[(18)F]fluoro-2-deoxy-D: -glucose positron emission tomography ((18)F-FDG PET)/CT versus (18)F-FDG PET and CT alone for staging and restaging of pediatric solid tumors. METHODS: Forty-three children and adolescents (19 females and 24 males; mean age, 15.2 years; age range, 6-20 years) with osteosarcoma (n = 1), squamous cell carcinoma (n = 1), synovial sarcoma (n = 2), germ cell tumor (n = 2), neuroblastoma (n = 2), desmoid tumor (n = 2), melanoma (n = 3), rhabdomyosarcoma (n = 5), Hodgkin's lymphoma (n = 7), non-Hodgkin-lymphoma (n = 9), and Ewing's sarcoma (n = 9) who had undergone (18)F-FDG PET/CT imaging for primary staging or follow-up of metastases were included in this study. The presence, location, and size of primary tumors was determined separately for PET/CT, PET, and CT by two experienced reviewers. The diagnosis of the primary tumor was confirmed by histopathology. The presence or absence of metastases was confirmed by histopathology (n = 62) or clinical and imaging follow-up (n = 238). RESULTS: The sensitivities for the detection of solid primary tumors using integrated (18)F-FDG PET/CT (95%), (18)F-FDG PET alone (73%), and CT alone (93%) were not significantly different (p > 0.05). Seventeen patients showed a total of 153 distant metastases. Integrated PET/CT had a significantly higher sensitivity for the detection of these metastases (91%) than PET alone (37%; p < 0.05), but not CT alone (83%; p > 0.05). When lesions with a diameter of less than 0.5 cm were excluded, PET/CT (89%) showed a significantly higher specificity compared to PET (45%; p < 0.05) and CT (55%; p < 0.05). In a sub-analysis of pulmonary metastases, the values for sensitivity and specificity were 90%, 14%, 82% and 63%, 78%, 65%, respectively, for integrated PET/CT, stand-alone PET, and stand-alone CT. For the detection of regional lymph node metastases, (18)F-FDG PET/CT, (18)F-FDG PET alone, and CT alone were diagnostically correct in 83%, 61%, and 42%. A sub-analysis focusing on the ability of PET/CT, PET, and CT to detect osseous metastases showed no statistically significant difference between the three imaging modalities (p > 0.05). CONCLUSION: Our study showed a significantly increased sensitivity of PET/CT over that of PET for the detection of distant metastases but not over that of CT alone. However, the specificity of PET/CT for the characterization of pulmonary metastases with a diameter > 0.5 cm and lymph node metastases with a diameter of <1 cm was significantly increased over that of CT alone.

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.

Liver steatosis: investigation of opposed-phase T1-weighted liver MR signal intensity loss and visceral fat measurement as biomarkers.

PURPOSE: To investigate if opposed-phase T1-weighted and fat-suppressed T2-weighted liver signal intensity (SI) loss and visceral fat measurement at magnetic resonance (MR) imaging and body mass index (BMI) are correlated with grade of liver steatosis in patients with nonalcoholic fatty liver disease (NAFLD) or hepatitis C virus (HCV) and human immunodeficiency virus (HIV)-related liver disease. MATERIALS AND METHODS: Committee on Human Research approval and patient consent were obtained for this HIPAA-compliant study. Fifty-two patients (15 men, 37 women) with NAFLD (n = 29) or HCV and HIV-related liver disease (n = 23) underwent prospective contemporaneous MR imaging and liver biopsy. Liver SI loss was measured on opposed-phase T1-weighted and fat-suppressed T2-weighted MR images. Visceral fat area was measured at three levels on water-suppressed T1-weighted MR images (n = 44). Spearman rank correlation coefficients and recursive partitioning were used to examine correlations. RESULTS: Histopathologic liver steatosis correlated well with liver SI loss on opposed-phase T1-weighted MR images (rho = 0.78), fat-suppressed T2-weighted MR images (rho = 0.75), and average visceral fat area (rho = 0.77) (all P < .01) but poorly with BMI (rho = 0.53, P < .01). Liver SI losses on opposed-phase T1-weighted MR imaging of less than 3%, at least 3% but less than 35%, at least 35% but less than 49%, and at least 49% corresponded to histopathologic steatosis grades of 0 (n = 16 of 17), 1 (n = 11 of 16), 2 (n = 7 of 13), and 3 (n = 5 of 6), respectively. A visceral fat area of greater than or equal to 73.8 cm(2) was associated with the presence of histopathologic steatosis in 41 of 44 patients. CONCLUSION: Liver SI loss on opposed-phase T1-weighted MR images and visceral fat area may be used as biomarkers for the presence of liver steatosis and appear to be superior to BMI.

An update survey of academic radiologists' clinical productivity.

RATIONALE AND OBJECTIVES: The total number of procedures and their relative value units (RVUs) were used to measure the productivity of radiologists. Besides variations in productivity due to differences in the percentage of clinical effort, baseline productivity also varies among clinical subspecialty sections. The authors' previous research used the full-time equivalent (FTE) as the unit to adjust for differences in the percentage of clinical effort and a set of adjustment factors (or calibration constants) to modify the default work RVUs according to types of procedures. These adjustments led to comparable average productivity measurements across subspecialty sections. Since 2003, radiology practice has continued to change, including the introduction of positron emission tomography/computed tomography into clinical practice, suggesting a need to update the understanding of clinical productivity and refine the authors' adjustment procedure. In this study, the authors analyzed the most recent survey of academic departments and derived updated adjustment factors for differences in workload among subspecialty sections. The results can be used to determine faculty staffing requirements and evaluate radiologists' performance. MATERIALS AND METHODS: A survey performed by the Society of Chairmen of Academic Radiology Departments collected data in 2006 for 1,134 radiologists in 24 departments, including 10 departments that also reported productivity in an earlier 2003 survey. These data included the numbers of procedures (represented by Current Procedural Terminology [CPT] codes) performed by radiologists, percentage clinical effort, subspecialty sections, and the number of clinical days. The numbers of CPT codes were converted into total work RVUs per FTE faculty member. By grouping the CPT codes into 6 prespecified examination categories, adjustment factors were created to adjust the RVUs for CPT categories to ensure that the median total adjusted work RVUs from different subspecialty sections were comparable. RESULTS: Overall, the mean clinical workload in 2006 was 9,671 examinations, a statistically significant 15% increase from 2003. The mean number of work RVUs per FTE was 7,136, a 22% increase from 2003. The adjustment factors have been modified from those presented in the authors' earlier paper, including reductions for interventional radiology, computed tomography, magnetic resonance imaging, nuclear medicine, and a new adjustment factor for "special procedures." These adjustments reduced differences in adjusted RVUs per FTE between subspecialty sections. CONCLUSIONS: Clinical workload, as measured by RVUs per FTE and adjusted RVUs per FTE, is very useful for determining optimal staffing in subspecialty sections and in radiology departments in general. Workload continues to increase, both in examination complexity and in numbers of overall procedures. Adjustment factors make workload comparisons between subspecialty sections more valid and meaningful.