Mythreyi Bhargavan-Chatfield

U.S. Diagnostic Reference Levels and Achievable Doses for 10 Adult CT Examinations

Purpose To develop diagnostic reference levels (DRLs) and achievable doses (ADs) for the 10 most common adult computed tomographic (CT) examinations in the United States as a function of patient size by using the CT Dose Index Registry. Materials and Methods Data from the 10 most commonly performed adult CT head, neck, and body examinations from 583 facilities were analyzed. For head examinations, the lateral thickness was used as an indicator of patient size; for neck and body examinations, water-equivalent diameter was used. Data from 1 310 727 examinations (analyzed by using SAS 9.3) provided median values, as well as means and 25th and 75th (DRL) percentiles for volume CT dose index (CTDIvol), dose-length product (DLP), and size-specific dose estimate (SSDE). Applicable results were compared with DRLs from eight countries. Results More than 46% of the facilities were community hospitals; 13% were academic facilities. More than 48% were in metropolitan areas, 39% were suburban, and 13% were rural. More than 50% of the facilities performed fewer than 500 examinations per month. The abdomen and pelvis was the most frequently performed examination in the study (45%). For body examinations, DRLs (75th percentile) and ADs (median) for CTDIvol, SSDE, and DLP increased consistently with the patients size (water-equivalent diameter). The relationships between patient size and DRLs and ADs were not as strong for head and neck examinations. These results agree well with the data from other countries. Conclusion DRLs and ADs as a function of patient size were developed for the 10 most common adult CT examinations performed in the United States.

The ACR Computed Tomography Dose Index Registry: The 5 Million Examination Update

The ACR opened the Computed Tomography Dose Index Registry (DIR) for general participation by all facilities in May 2011. Just over 2 years after its launch, the registry has more than 750 registered facilities, 465 of which were actively contributing data at the end of August 2013. The registry has dose index information on 5.5 million CT examinations, which in turn include 9.4 million irradiation events. Participating facilities receive semiannual reports that provide comparisons of dose indices for each procedure relative to all other facilities in the registry and to facilities similar by type and location. The purpose of the registry is to provide facilities a tool to allow them to compare their dose indices with those at peer facilities and make improvements where appropriate. Data on dose indices for all CT examinations are collected and transmitted automatically from each facility to the DIR, after anonymization of data at the site. For each examination, dose indices are compared using volume CT dose index (CTDIvol), dose-length product, and, for body examinations, size-specific dose estimate (SSDE). Fair and meaningful comparison required us to standardize data collection and estimation, procedure nomenclature, and reporting. This article describes the current state of the registry and the implementation of these standards.

The National Mammography Database: Preliminary Data

OBJECTIVE The purposes of our study were to analyze screening mammography data submitted to the National Mammography Database (NMD) since its inception to confirm data collection feasibility, to draw parallels to data from the Breast Cancer Surveillance Consortium (BCSC), and to examine trends over time. We also retrospectively evaluated practice-level variation in terms of practice type, practice setting, census region, and annual volume. MATERIALS AND METHODS Data from 90 mammography facilities in the NMD registry were analyzed. The registry receives mammography data collected as part of standard clinical practice, including self-reported demographic information, clinical findings, screening mammography interpretation, and biopsy results. Outcome metrics calculated were cancer detection rate, recall rate, and positive predictive values for biopsy recommended (PPV2) and biopsy performed (PPV3). RESULTS The NMD successfully collected and analyzed data for 3,181,437 screening mammograms performed between January 2008 and December 2012. Mean values for outcomes were cancer detection rate of 3.43 per 1000 (95% CI, 3.2-3.7), recall rate of 10% (95% CI, 9.3-10.7%), PPV2 of 18.5% (95% CI, 16.7-20.2%), and PPV3 of 29.2% (95% CI, 26.2-32.3%). No statistically significant difference was seen in performance measurements on the basis of practice type, practice setting, census region, or annual volume. NMD performance measurements parallel those reported by the BCSC. CONCLUSION The NMD has become the fastest growing mammography registry in the United States, providing nationwide performance metrics and permitting comparison with published benchmarks. Our study shows the feasibility of using the NMD to audit mammography facilities and to provide current, ongoing benchmark data.

Intravenous Contrast Extravasation During CT: A National Data Registry and Practice Quality Improvement Initiative

PURPOSE Establish 3 performance benchmarks for intravenous contrast extravasation during CT examinations: extravasation frequency, distribution of extravasation volumes, and severity of injury. Evaluate the effectiveness of implementing practice quality improvement (PQI) methodology in improving performance for these 3 benchmarks. METHODS The Society of Abdominal Radiology and ACR developed a registry collecting data for contrast extravasation events. The project includes a PQI initiative allowing for process improvement. RESULTS As of December 2013, a total of 58 radiology practices have participated in this project, and 32 practices have completed the 2-cycle PQI. There were a total of 454,497 contrast-enhanced CT exams and 1,085 extravasation events. The average extravasation rate is 0.24%. The median extravasation rate is 0.21%. Most extravasations (82.9%) were between 10 mL and 99 mL. The majority of injuries, 94.6%, are mild in severity, with 4.7% having moderate and 0.8% having severe injuries. Data from practices that completed the PQI process showed a change in the average extravasation rate from 0.28% in the first 6 months to 0.23% in the second 6 months, and the median extravasation rate dropped from 0.25% to 0.16%, neither statistically significant. The distribution of extravasation volumes and the severity of injury did not change between the first and second measurement periods. CONCLUSIONS National performance benchmarks for contrast extravasation rate, distribution of volumes of extravasate, and distribution of severity of injury are established through this multi-institutional practice registry. The application of PQI failed to have a statistically significant positive impact on any of the 3 benchmarks.

Interreader Reliability of LI-RADS Version 2014 Algorithm and Imaging Features for Diagnosis of Hepatocellular Carcinoma: A Large International Multireader Study

Purpose To determine in a large multicenter multireader setting the interreader reliability of Liver Imaging Reporting and Data System (LI-RADS) version 2014 categories, the major imaging features seen with computed tomography (CT) and magnetic resonance (MR) imaging, and the potential effect of reader demographics on agreement with a preselected nonconsecutive image set. Materials and Methods Institutional review board approval was obtained, and patient consent was waived for this retrospective study. Ten image sets, comprising 38-40 unique studies (equal number of CT and MR imaging studies, uniformly distributed LI-RADS categories), were randomly allocated to readers. Images were acquired in unenhanced and standard contrast material-enhanced phases, with observation diameter and growth data provided. Readers completed a demographic survey, assigned LI-RADS version 2014 categories, and assessed major features. Intraclass correlation coefficient (ICC) assessed with mixed-model regression analyses was the metric for interreader reliability of assigning categories and major features. Results A total of 113 readers evaluated 380 image sets. ICC of final LI-RADS category assignment was 0.67 (95% confidence interval [CI]: 0.61, 0.71) for CT and 0.73 (95% CI: 0.68, 0.77) for MR imaging. ICC was 0.87 (95% CI: 0.84, 0.90) for arterial phase hyperenhancement, 0.85 (95% CI: 0.81, 0.88) for washout appearance, and 0.84 (95% CI: 0.80, 0.87) for capsule appearance. ICC was not significantly affected by liver expertise, LI-RADS familiarity, or years of postresidency practice (ICC range, 0.69-0.70; ICC difference, 0.003-0.01 [95% CI: -0.003 to -0.01, 0.004-0.02]. ICC was borderline higher for private practice readers than for academic readers (ICC difference, 0.009; 95% CI: 0.000, 0.021). Conclusion ICC is good for final LI-RADS categorization and high for major feature characterization, with minimal reader demographic effect. Of note, our results using selected image sets from nonconsecutive examinations are not necessarily comparable with those of prior studies that used consecutive examination series.

Association of Patient Age With Outcomes of Current-Era, Large-Scale Screening Mammography: Analysis of Data From the National Mammography Database

This study analyzes mammography screening data from the National Mammography Database to determine the age cutoff point for screening.

American College of Radiology Dose Index Registry: A User's Guide for Cardiothoracic Radiologists Part 1: Dose Index Registry (DIR)-What it Means and Does for CT?

Computed tomography (CT) is an indispensable part of diagnostic imaging and contributes significantly to patient care. With increasing use of CT, there have been growing concerns regarding risks from radiation exposure. This has prompted efforts to introduce measures to optimize the radiation dose used in CT imaging. The Dose Index Registry (DIR) was launched by the American College of Radiology (ACR) in 2011. It provides a national database of radiation dose indices for various CT examinations performed at participating institutions. It affords an opportunity for institutions to compare and tailor their CT protocols against existing national averages. In this article, we review the history, mechanism, and major elements of the DIR. We also briefly discuss similar radiation dose registries in other countries.

Pediatric Chest CT Diagnostic Reference Ranges: Development and Application

Purpose To determine diagnostic reference ranges on the basis of the size of a pediatric patients chest and to develop a method to estimate computed tomographic (CT) scanner-specific mean size-specific dose estimates (SSDEs) as a function of patient size and the radiation output of each CT scanner at a site. Materials and Methods The institutional review boards of each center approved this retrospective, HIPAA-compliant, multicenter study; informed consent was waived. CT dose indexes (SSDE, volume CT dose index, and dose length product) of 518 pediatric patients (mean age, 9.6 years; male patients, 277 [53%]) who underwent CT between July 1, 2012, and June 30, 2013, according to the guidelines of the Quality Improvement Registry in CT Scans in Children were retrieved from a national dose data registry. Diagnostic reference ranges were developed after analysis of image quality of a subset of 111 CT examinations to validate image quality at the lower bound. Pediatric dose reduction factors were calculated on the basis of SSDEs for pediatric patients divided by SSDEs for adult patients. Results Diagnostic reference ranges (SSDEs) were 1.8-3.9, 2.2-4.5, 2.7-5.1, 3.6-6.6, and 5.5-8.4 mGy for effective diameter ranges of less than 15 cm, 15-19 cm, 20-24 cm, 25-29 cm, and greater than or equal to 30 cm, respectively. The fractions of adult doses (pediatric dose reduction factors) used within the consortium for patients with lateral dimensions of 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, and 38 cm were 0.29, 0.33, 0.38, 0.44, 0.50, 0.58, 0.66, 0.76, 0.87, 1.0, and 1.15, respectively. Conclusion Diagnostic reference ranges developed in this study provided target ranges of pediatric dose indexes on the basis of patient size, while the pediatric dose reduction factors of this study allow calculation of unique reference dose indexes on the basis of patient size for each of a sites CT scanners.

Clinical Implementation of the National Electrical Manufacturers Association CT Dose Check Standard at ACR Dose Index Registry Sites

PURPOSE The goal of the study was to determine if and how the National Electrical Manufacturers Association CT Dose Check standard has been implemented in clinical practice. METHODS A survey was conducted of all sites participating in the ACR Dose Index Registry, using a web-based survey instrument, to determine whether respondents were aware of the CT Dose Check standard and the American Association of Physicists in Medicine (AAPM) recommendations for Dose Alert values, and if clinical sites had implemented it. RESULTS A total of 170 responses were received, representing 37% (170/460) of surveys sent and 23% (170/734) of facilities participating in the ACR Dose Index Registry. Of responding facilities, 57.1% (96/168) were aware of the CT Dose Check standard, and 51.2% (86/168) were aware of the AAPM recommendations. At 44% (73/165) of responding facilities, at least 1 CT scanner with Dose Check capability was present. Of sites responding that they had at least 1 CT scanner with this capability, 57% (42/74) had implemented Dose Alerts, and 71% (30/42) had implemented Dose Notifications on CT scanners with the capability. Most responding sites were located in community hospitals (55.8%; 86/154). CONCLUSIONS Although the National Electrical Manufacturers Association CT Dose Check standard and the AAPM recommendations for its use had been available for at least 2 years at the time of the survey, nearly half of the participating sites were not familiar with them. Education and outreach are needed if this tool is to be used effectively.

MRI of the Knee and Shoulder Performed Before Radiography

PURPOSE Available data are limited on the level of adherence to established guidelines for appropriate utilization of MR in musculoskeletal imaging. This study estimates the percentage of MRI examinations for knee and shoulder pain or tendonitis performed without prior radiography, which thus may fall outside the ACR Appropriateness Criteria for the Medicare and commercially insured populations. METHODS The percentage of MRI examinations for knee and shoulder pain or tendonitis performed without prior radiography was estimated among patients in the Medicare 5% carrier claims limited data set and among commercially insured patients in the Truven Marketscan Treatment Pathways database in 2010. RESULTS Approximately 28% of all knee MRIs, and 35%-37% of all shoulder MRIs were performed without recent prior radiographs. The extrapolated expense of these potentially unwarranted MRIs in the entire fee-for-service Medicare population was between