Browsing by Subject "Quality Assurance, Health Care"

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    ItemOpen Access
    Automated quality control in nuclear medicine using the structured noise index.
    (Journal of applied clinical medical physics, 2020-04) Nelson, Jeffrey S; Samei, Ehsan

    Purpose

    Daily flood-field uniformity evaluation serves as the central element of nuclear medicine (NM) quality control (QC) programs. Uniformity images are traditionally analyzed using pixel value-based metrics, that is, integral uniformity (IU), which often fail to capture subtle structure and patterns caused by changes in gamma camera performance, requiring visual inspections which are subjective and time demanding. The goal of this project was to implement an advanced QC metrology for NM to effectively identify nonuniformity issues, and report issues in a timely manner for efficient correction prior to clinical use. The project involved the implementation of the program over a 2-year period at a multisite major medical institution.

    Methods

    Using a previously developed quantitative uniformity analysis metric, the structured noise index (SNI) [Nelson et al. (2014), \textit{J Nucl Med.}, \textbf{55}:169-174], an automated QC process was developed to analyze, archive, and report on daily NM QC uniformity images. Clinical implementation of the newly developed program ran in parallel with the manufacturer's reported IU-based QC program. The effectiveness of the SNI program was evaluated over a 21-month period using sensitivity and coefficient of variation statistics.

    Results

    A total of 7365 uniformity QC images were analyzed. Lower level SNI alerts were generated in 12.5% of images and upper level alerts in 1.7%. Intervention due to image quality issues occurred on 26 instances; the SNI metric identified 24, while the IU metric identified eight. The SNI metric reported five upper level alerts where no clinical engineering intervention was deemed necessary.

    Conclusion

    An SNI-based QC program provides a robust quantification of the performance of gamma camera uniformity. It operates seamlessly across a fleet of multiple camera models and, additionally, provides effective workflow among the clinical staff. The reliability of this process could eliminate the need for visual inspection of each image, saving valuable time, while enabling quantitative analysis of inter- and intrasystem performance.
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    Causes of the change in the rates of mortality and severe complications of diabetes mellitus: 1992-2012.
    (Med Care, 2015-03) Yashkin, Arseniy P; Picone, Gabriel; Sloan, Frank
    OBJECTIVE: To quantify the causes of the changes in the rates of mortality and select severe complications of diabetes mellitus, type 2 (T2D) among the elderly between 1992 and 2012. RESEARCH DESIGN: A retrospective cohort study design based on Medicare 5% administrative claims data from 1992 to 2012 was used. Traditional fee-for-service Medicare beneficiaries, age 65 and older, diagnosed with T2D and living in the United States between 1992 and 2012 were included in the study. Blinder-Oaxaca decomposition was used to quantify the potential causes of the change in the rates of death, congestive heart failure and/or acute myocardial infarction, stroke, amputation of lower extremity and end-stage renal disease between 1992 and 2012. RESULTS: The number of beneficiaries in the analysis sample diagnosed with T2D increased from 152,191 in 1992 to 289,443 in 2012. Over the same time period, rates of mortality decreased by 1.2, congestive heart failure and/or acute myocardial infarction by 2.6, stroke by 1.6, amputation by 0.6 while rates of end-stage renal disease increased by 1.5 percentage points. Improvements in the management of precursor conditions and utilization of recommended healthcare services, not population composition, were the primary causes of the change. CONCLUSIONS: With the exception of end-stage renal disease, outcomes among Medicare beneficiaries diagnosed with T2D improved. Analysis suggests that persons diagnosed with T2D are living longer with fewer severe complications. Much of the improvement in outcomes likely reflects more regular contact with health professionals and better management of care.
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    Comparisons of volumetric modulated arc therapy (VMAT) quality assurance (QA) systems: sensitivity analysis to machine errors.
    (Radiation Oncology (London, England), 2016-11-07) Liang, Bin; Liu, Bo; Zhou, Fugen; Yin, Fang-Fang; Wu, Qiuwen
    In volumetric modulated arc therapy (VMAT), gantry angles, dose rate and the MLC positions vary with the radiation delivery. The quality assurance (QA) system should be able to catch the planning and machine errors. The aim of this study was to investigate the sensitivity of three VMAT QA systems to machine errors.Several types of potential linac machine errors unique to VMAT delivery were simulated in sinusoidal function of gantry angle, including gantry angle itself, MLC position and linac output. Two commercial QA systems, ArcCheck and Delta4, and an in-house developed EPID technique were compared in this study. Fifteen full arcs from head and neck plans were selected and modified to include five magnitudes of each type of error, resulting in measurements and γ analyses of 240 arcs on each system. Both qualitative and quantitative comparisons were performed using receiver operating characteristic (ROC), γ pass rate gradient, and overlap histogram methods.In ROC analysis, the area under curve (AUC) represents the sensitivity and increases with the error magnitude. Using the criteria of 2 %/2 mm/2° (angle to agreement, ATA, only for EPID) and keeping AUC > 0.95, the minimum error detectable of ArcCheck, Delta4 and EPID are (2, 3, 3)° in gantry angle and (4, 2, 3) mm in MLC positions for the head and neck plans. No system is sensitive to the simulated output error, the AUC values were all below 0.70 even with 5 % output error. The γ gradient for gantry angle, MLC position and output errors are (-5.1, -2.6, -3.6)%/°, (-2.6, -7.1, -3.3)%/mm and (-0.2, -0.2, -0.3)%/% for ArcCheck, Delta4 and EPID, respectively. Therefore, these two analyses are consistent and support the same conclusion. The ATA parameter in EPID technique can be adjusted to tune its sensitivity.We found that ArcCheck is more sensitive to gantry angle error and Delta4 is more sensitive to MLC position error. All three systems are not sensitive to the simulated output error. With additional analysis parameter, the EPID technique can be tuned to have optimal sensitivity and is able to perform QA for full field size with highest resolution. In addition, ROC analysis avoids the choice of γ pass rate threshold and is more robust compared with other analysis methods.
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    ItemOpen Access
    Critical Review of Current Approaches for Echocardiographic Reproducibility and Reliability Assessment in Clinical Research.
    (Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography, 2016-12) Crowley, Anna Lisa; Yow, Eric; Barnhart, Huiman X; Daubert, Melissa A; Bigelow, Robert; Sullivan, Daniel C; Pencina, Michael; Douglas, Pamela S

    Background

    There is no broadly accepted standard method for assessing the quality of echocardiographic measurements in clinical research reports, despite the recognized importance of this information in assessing the quality of study results.

    Methods

    Twenty unique clinical studies were identified reporting echocardiographic data quality for determinations of left ventricular (LV) volumes (n = 13), ejection fraction (n = 12), mass (n = 9), outflow tract diameter (n = 3), and mitral Doppler peak early velocity (n = 4). To better understand the range of possible estimates of data quality and to compare their utility, reported reproducibility measures were tabulated, and de novo estimates were then calculated for missing measures, including intraclass correlation coefficient (ICC), 95% limits of agreement, coefficient of variation (CV), coverage probability, and total deviation index, for each variable for each study.

    Results

    The studies varied in approaches to reproducibility testing, sample size, and metrics assessed and values reported. Reported metrics included mean difference and its SD (n = 7 studies), ICC (n = 5), CV (n = 4), and Bland-Altman limits of agreement (n = 4). Once de novo estimates of all missing indices were determined, reasonable reproducibility targets for each were identified as those achieved by the majority of studies. These included, for LV end-diastolic volume, ICC > 0.95, CV < 7%, and coverage probability > 0.93 within 30 mL; for LV ejection fraction, ICC > 0.85, CV < 8%, and coverage probability > 0.85 within 10%; and for LV mass, ICC > 0.85, CV < 10%, and coverage probability > 0.60 within 20 g.

    Conclusions

    Assessment of data quality in echocardiographic clinical research is infrequent, and methods vary substantially. A first step to standardizing echocardiographic quality reporting is to standardize assessments and reporting metrics. Potential benefits include clearer communication of data quality and the identification of achievable targets to benchmark quality improvement initiatives.
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    Cross-platform analysis of HIV-1 RNA data generated by a multicenter assay validation study with wide geographic representation.
    (J Clin Microbiol, 2012-08) Jennings, Cheryl; Harty, Brian; Granger, Suzanne; Wager, Carrie; Crump, John A; Fiscus, Susan A; Bremer, James W
    HIV-1 RNA quantitation continues to be extremely important for monitoring patients infected with HIV-1, and a number of assays have been utilized for this purpose. Differences in assay performance with respect to log(10) recovery and HIV-1 subtype specificity have been well documented for commercially available assays, although comparisons are usually limited to one or two assay platforms. Two new FDA-approved assays, the Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 test (RT) and the Abbott RealTime HIV-1 assay (AR), that utilize real-time PCR have replaced previous HIV-1 RNA platforms. Inadequate detection of some strains of HIV-1 resulted in the addition of a new primer/probe set and the introduction of a second version of the RT assay. In this study, comparisons of assay performance between the different FDA-approved HIV-1 RNA assay platforms (both new and existing) were performed by using validation data that included both well-characterized virus stock and locally collected clinical samples. Laboratories across diverse geographical regions performed the validation testing and submitted data to the Virology Quality Assurance program (VQA) for analysis. Correlation values for clinical sample testing varied across the assay platforms (r = 0.832 to 0.986), and average log(10) recoveries for HIV-1 RNA controls (compared to the nominal value) ranged from -0.215 to 0.181. These data demonstrate the need for use of one assay platform for longitudinal patient monitoring, but the data also reinforce the notion that no one assay is superior and that testing across platforms may be required for discordance reconciliation.
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    ItemOpen Access
    Current definitions of central line-associated bloodstream infection: is the emperor wearing clothes?
    (Infect Control Hosp Epidemiol, 2010-12) Sexton, Daniel J; Chen, Luke F; Anderson, Deverick J
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    Diode-based transmission detector for IMRT delivery monitoring: a validation study.
    (Journal of applied clinical medical physics, 2016-09-08) Li, Taoran; Wu, Q Jackie; Matzen, Thomas; Yin, Fang-Fang; O'Daniel, Jennifer C
    The purpose of this work was to evaluate the potential of a new transmission detector for real-time quality assurance of dynamic-MLC-based radiotherapy. The accuracy of detecting dose variation and static/dynamic MLC position deviations was measured, as well as the impact of the device on the radiation field (surface dose, transmission). Measured dose variations agreed with the known variations within 0.3%. The measurement of static and dynamic MLC position deviations matched the known deviations with high accuracy (0.7-1.2 mm). The absorption of the device was minimal (~ 1%). The increased surface dose was small (1%-9%) but, when added to existing collimator scatter effects could become significant at large field sizes (≥ 30 × 30 cm2). Overall the accuracy and speed of the device show good potential for real-time quality assurance.
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    ItemOpen Access
    Implementing diffusion-weighted MRI for body imaging in prospective multicentre trials: current considerations and future perspectives.
    (European radiology, 2018-03) deSouza, NM; Winfield, JM; Waterton, JC; Weller, A; Papoutsaki, M-V; Doran, SJ; Collins, DJ; Fournier, L; Sullivan, D; Chenevert, T; Jackson, A; Boss, M; Trattnig, S; Liu, Y
    For body imaging, diffusion-weighted MRI may be used for tumour detection, staging, prognostic information, assessing response and follow-up. Disease detection and staging involve qualitative, subjective assessment of images, whereas for prognosis, progression or response, quantitative evaluation of the apparent diffusion coefficient (ADC) is required. Validation and qualification of ADC in multicentre trials involves examination of i) technical performance to determine biomarker bias and reproducibility and ii) biological performance to interrogate a specific aspect of biology or to forecast outcome. Unfortunately, the variety of acquisition and analysis methodologies employed at different centres make ADC values non-comparable between them. This invalidates implementation in multicentre trials and limits utility of ADC as a biomarker. This article reviews the factors contributing to ADC variability in terms of data acquisition and analysis. Hardware and software considerations are discussed when implementing standardised protocols across multi-vendor platforms together with methods for quality assurance and quality control. Processes of data collection, archiving, curation, analysis, central reading and handling incidental findings are considered in the conduct of multicentre trials. Data protection and good clinical practice are essential prerequisites. Developing international consensus of procedures is critical to successful validation if ADC is to become a useful biomarker in oncology.• Standardised acquisition/analysis allows quantification of imaging biomarkers in multicentre trials. • Establishing "precision" of the measurement in the multicentre context is essential. • A repository with traceable data of known provenance promotes further research.
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    Measuring blood pressure for decision making and quality reporting: where and how many measures?
    (Annals of internal medicine, 2011-06) Powers, Benjamin J; Olsen, Maren K; Smith, Valerie A; Woolson, Robert F; Bosworth, Hayden B; Oddone, Eugene Z

    Background

    The optimal setting and number of blood pressure (BP) measurements that should be used for clinical decision making and quality reporting are uncertain.

    Objective

    To compare strategies for home or clinic BP measurement and their effect on classifying patients as having BP that was in or out of control.

    Design

    Secondary analysis of a randomized, controlled trial of strategies to improve hypertension management. (ClinicalTrials.gov registration number: NCT00237692)

    Setting

    Primary care clinics affiliated with the Durham Veterans Affairs Medical Center.

    Patients

    444 veterans with hypertension followed for 18 months.

    Measurements

    Blood pressure was measured repeatedly by using 3 methods: standardized research BP measurements at 6-month intervals; clinic BP measurements obtained during outpatient visits; and home BP measurements using a monitor that transmitted measurements electronically.

    Results

    Patients provided 111,181 systolic BP (SBP) measurements (3218 research, 7121 clinic, and 100,842 home measurements) over 18 months. Systolic BP control rates at baseline (mean SBP<140 mm Hg for clinic or research measurement; <135 mm Hg for home measurement) varied substantially, with 28% classified as in control by clinic measurement, 47% by home measurement, and 68% by research measurement. Short-term variability was large and similar across all 3 methods of measurement, with a mean within-patient coefficient of variation of 10% (range, 1% to 24%). Patients could not be classified as having BP that was in or out of control with 80% certainty on the basis of a single clinic SBP measurement from 120 mm Hg to 157 mm Hg. The effect of within-patient variability could be greatly reduced by averaging several measurements, with most benefit accrued at 5 to 6 measurements.

    Limitation

    The sample was mostly men with a long-standing history of hypertension and was selected on the basis of previous poor BP control.

    Conclusion

    Physicians who want to have 80% or more certainty that they are correctly classifying patients' BP control should use the average of several measurements. Hypertension quality metrics based on a single clinic measurement potentially misclassify a large proportion of patients.

    Primary funding source

    U.S. Department of Veterans Affairs Health Services Research and Development Service.
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    ItemOpen Access
    Performance of accredited social health activists to provide home-based newborn care: a situational analysis.
    (Indian pediatrics, 2014-02) Das, Emily; Panwar, Dharmendra Singh; Fischer, Elizabeth A; Bora, Girdhari; Carlough, Martha C

    Objective

    To assess Accredited social health activists' (ASHAs) ability to recognize illness in infants aged less than 2 months.

    Methods

    Investigators observed 25 ASHAs conducting 47 visits.

    Results

    ASHA-investigator agreement on the need to further assess infants was intermediate (kappa 0.48, P<0.001). Using IMNCI's color codes, ASHAs misclassified 80% of infants. ASHAs did not follow home-based newborn care formats and skipped critical signs. Overall ASHA-investigator agreement on diagnosis was poor (kappa=0.23, P=0.01).

    Conclusion

    There is a need for improved training, tools, and supportive supervision.