RESUMO
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.
Assuntos
Doses de Radiação , Tomografia Computadorizada por Raios X , Humanos , Tomografia Computadorizada por Raios X/métodos , Radiologistas , Estados Unidos , Melhoria de QualidadeRESUMO
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.
Assuntos
Exposição à Radiação , Tomografia Computadorizada por Raios X , Adulto , Humanos , Doses de Radiação , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , AbdomeRESUMO
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.
Assuntos
Biomarcadores Tumorais/análise , Neoplasias da Mama/terapia , Recidiva Local de Neoplasia , Adulto , Idoso , Neoplasias da Mama/química , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Neoplasias da Mama/secundário , Proliferação de Células , Intervalo Livre de Doença , Feminino , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Londres , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Modelos de Riscos Proporcionais , Receptor ErbB-2/análise , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do TratamentoRESUMO
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.
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Astrocitoma/patologia , Colina/metabolismo , Adulto , Astrocitoma/metabolismo , Biópsia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Proliferação de Células , Feminino , Glioma/metabolismo , Glicerilfosforilcolina/farmacologia , Humanos , Imuno-Histoquímica/métodos , Antígeno Ki-67/biossíntese , Espectroscopia de Ressonância Magnética/métodos , Masculino , Neovascularização Patológica , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
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.
Assuntos
Neoplasias/diagnóstico , Neoplasias/patologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Metástase Neoplásica/diagnóstico por imagem , Estadiamento de Neoplasias , Neoplasias/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Estudos Retrospectivos , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios XRESUMO
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.
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Neoplasias da Mama/diagnóstico por imagem , Comportamentos Relacionados com a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Mamografia/psicologia , Mamografia/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/psicologia , Etnicidade/psicologia , Feminino , Comportamentos Relacionados com a Saúde/etnologia , Acessibilidade aos Serviços de Saúde/economia , Humanos , Mamografia/economia , Pessoa de Meia-Idade , Razão de Chances , Relações Médico-Paciente , Fatores de Risco , Fatores Socioeconômicos , Adulto JovemRESUMO
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.
Assuntos
Biomarcadores , Fígado Gorduroso/diagnóstico , Gordura Intra-Abdominal/anatomia & histologia , Fígado , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Idoso , Biópsia , Índice de Massa Corporal , Criança , Fígado Gorduroso/complicações , Fígado Gorduroso/patologia , Feminino , Infecções por HIV/complicações , Hepatite C/complicações , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
BACKGROUND: Medicare data may be a useful source for determining the utilization of mammography among elderly women, but the accuracy of these data has not been established. OBJECTIVE: We determined whether Medicare physician billing claims are an accurate reflection of mammography utilization among women ages 65 and older and whether they can be used to assess the use of screening as compared with diagnostic mammography. DATA SOURCES: Mammography use was assessed using Medicare billing claims and radiology reports from 2 mammography registries; the San Francisco Mammography Registry and the New Mexico Mammography Registry. METHODS: Completeness of the Medicare data was assessed by comparing mammography use based on Medicare, with radiology reports from the mammography registries, which served as the referent standard. Capture rates for Medicare claims for individual mammograms were examined, and women were characterized as having undergone at least 1 mammogram within each 2-year period based on the Medicare data, and these rates were compared with the referent standard. To determine whether Medicare data can distinguish between screening and diagnostic mammography, we performed a classification analysis using the mammography registries screening/diagnostic designation as the referent standard (dependent variable) and Medicare claim information as the independent/predictor variable. On the basis of the mammogram level classification analysis, women were categorized as having been frequently screened (at least 2 screening mammograms spaced by 12 to 36 months), screened (at least 1 screening mammogram), or not screened. SUBJECTS: Women ages 65 and older, diagnosed with breast cancer between 1992-1999, who had at least 1 mammogram between 1992-1999 were examined. RESULTS: A total of 3340 mammograms were obtained in 1371 women between 1992 and 1999. Overall, 83% of mammograms obtained by these women had a corresponding billing claim in Medicare. This increased from 65% in 1992 to 90% in 1999. Of women who underwent at least 1 mammogram during each 2-year period per the referent standard, 94% of women were accurately classified by Medicare claims as also having undergone mammography during the same 2-year period. In multivariable analysis, a mammogram was more likely to be associated with a billing claim over time, for women 80 years or older, and for white and Asian as compared with Hispanic women. Neither socioeconomic status nor screening/diagnostic designation affected the likelihood that a mammogram would be associated with a billing claim. The Medicare data accurately categorized a given mammogram as screening or diagnostic for 87.5% of mammograms. Lastly, there was moderate to substantial agreement in the categorization of women as frequently screened, screened or not screened between the 2 data sets (weighted kappa 0.74, 95% confidence interval 0.70-0.78). CONCLUSION: Medicare administrative claims are reliable for assessment of mammography utilization and have become more accurate over time. Medicare claims data also provide a mechanism for designating mammography as screening or diagnostic, which subsequently may allow accurate description of a woman's screening history.
Assuntos
Mamografia/estatística & dados numéricos , Programas de Rastreamento/estatística & dados numéricos , Medicare/economia , Medicare/estatística & dados numéricos , Revisão da Utilização de Recursos de Saúde/métodos , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/diagnóstico por imagem , Feminino , Humanos , Mamografia/economia , Programas de Rastreamento/economia , Análise Multivariada , New Mexico , Grupos Raciais/estatística & dados numéricos , Sistema de Registros , São Francisco , Fatores SocioeconômicosRESUMO
CONTEXT: Screening mammography differs between the United States and the United Kingdom; a direct comparison may suggest methods to improve the practice. OBJECTIVE: To compare screening mammography performance between the United States and the United Kingdom among similar-aged women. DESIGN, SETTING, AND PARTICIPANTS: Women aged 50 years or older were identified who underwent 5.5 million mammograms from January 1, 1996, to December 31, 1999, within 3 large-scale mammography registries or screening programs: the Breast Cancer Surveillance Consortium (BCSC, n = 978 591) and National Breast and Cervical Cancer Early Detection Program (NBCCEDP, n = 613 388) in the United States; and the National Health Service Breast Screening Program (NHSBSP, n = 3.94 million) in the United Kingdom. A total of 27 612 women were diagnosed with breast cancer (invasive or ductal carcinoma in situ) within 12 months of screening among the 3 groups. MAIN OUTCOME MEASURES: Recall rates (recommendation for further evaluation including diagnostic imaging, ultrasound, clinical examination, or biopsy) and cancer detection rates were calculated for first and subsequent mammograms, and within 5-year age groups. RESULTS: Recall rates were approximately twice as high in the United States than in the United Kingdom for all age groups; however, cancer rates were similar. Among women aged 50 to 54 years who underwent a first screening mammogram, 14.4% in the BCSC and 12.5% in the NBCCEDP were recalled for further evaluation vs only 7.6% in the NHSBSP. Cancer detection rates per 1000 mammogram screens were 5.8, 5.9, and 6.3, in the BCSC, NBCCEDP, and NHSBSP, respectively. Recall rates were lower for subsequent examinations in all 3 settings but remained twice as high in the United States. A similar percentage of women underwent biopsy in each setting, but rates of percutaneous biopsy were lower and open surgical biopsy higher in the United States. Open surgical biopsies not resulting in a diagnosis of cancer (negative biopsies) were twice as high in the United States than in the United Kingdom. Based on a 10-year period of screening 1000 women aged 50 to 59 years, 477, 433, and 175 women in the BCSC, NBCCEDP, and NHSBSP, respectively, would be recalled; and for women aged 60 to 69 years, 396, 334, and 133 women, respectively. The estimated cancer detection rates per 1000 women aged 50 to 59 years were 24.5, 23.8, and 19.4, respectively, and for women aged 60 to 69 years, 31.5, 26.6, and 27.9, respectively. CONCLUSIONS: Recall and negative open surgical biopsy rates are twice as high in US settings than in the United Kingdom but cancer detection rates are similar. Efforts to improve US mammographic screening should target lowering the recall rate without reducing the cancer detection rate.