Dataset Information

T1 mapping performance and measurement repeatability: results from the multi-national T1 mapping standardization phantom program (T1MES).

ABSTRACT: BACKGROUND:The T1 Mapping and Extracellular volume (ECV) Standardization (T1MES) program explored T1 mapping quality assurance using a purpose-developed phantom with Food and Drug Administration (FDA) and Conformité Européenne (CE) regulatory clearance. We report T1 measurement repeatability across centers describing sequence, magnet, and vendor performance. METHODS:Phantoms batch-manufactured in August 2015 underwent 2?years of structural imaging, B0 and B1, and "reference" slow T1 testing. Temperature dependency was evaluated by the United States National Institute of Standards and Technology and by the German Physikalisch-Technische Bundesanstalt. Center-specific T1 mapping repeatability (maximum one scan per week to minimum one per quarter year) was assessed over mean 358 (maximum 1161) days on 34 1.5?T and 22 3?T magnets using multiple T1 mapping sequences. Image and temperature data were analyzed semi-automatically. Repeatability of serial T1 was evaluated in terms of coefficient of variation (CoV), and linear mixed models were constructed to study the interplay of some of the known sources of T1 variation. RESULTS:Over 2?years, phantom gel integrity remained intact (no rips/tears), B0 and B1 homogenous, and "reference" T1 stable compared to baseline (% change at 1.5?T, 1.95?±?1.39%; 3?T, 2.22?±?1.44%). Per degrees Celsius, 1.5?T, T1 (MOLLI 5s(3s)3s) increased by 11.4?ms in long native blood tubes and decreased by 1.2?ms in short post-contrast myocardium tubes. Agreement of estimated T1 times with "reference" T1 was similar across Siemens and Philips CMR systems at both field strengths (adjusted R2 ranges for both field strengths, 0.99-1.00). Over 1?year, many 1.5?T and 3?T sequences/magnets were repeatable with mean CoVs

SUBMITTER: Captur G

PROVIDER: S-EPMC7204222 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

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T<sub>1</sub> mapping performance and measurement repeatability: results from the multi-national T<sub>1</sub> mapping standardization phantom program (T1MES).

Captur Gabriella G Bhandari Abhiyan A Brühl Rüdiger R Ittermann Bernd B Keenan Kathryn E KE Yang Ye Y Eames Richard J RJ Benedetti Giulia G Torlasco Camilla C Ricketts Lewis L Boubertakh Redha R Fatih Nasri N Greenwood John P JP Paulis Leonie E M LEM Lawton Chris B CB Bucciarelli-Ducci Chiara C Lamb Hildo J HJ Steeds Richard R Leung Steve W SW Berry Colin C Valentin Sinitsyn S Flett Andrew A de Lange Charlotte C DeCobelli Francesco F Viallon Magalie M Croisille Pierre P Higgins David M DM Greiser Andreas A Pang Wenjie W Hamilton-Craig Christian C Strugnell Wendy E WE Dresselaers Tom T Barison Andrea A Dawson Dana D Taylor Andrew J AJ Mongeon François-Pierre FP Plein Sven S Messroghli Daniel D Al-Mallah Mouaz M Grieve Stuart M SM Lombardi Massimo M Jang Jihye J Salerno Michael M Chaturvedi Nish N Kellman Peter P Bluemke David A DA Nezafat Reza R Gatehouse Peter P Moon James C JC

Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance 20200507 1

<h4>Background</h4>The T<sub>1</sub> Mapping and Extracellular volume (ECV) Standardization (T1MES) program explored T<sub>1</sub> mapping quality assurance using a purpose-developed phantom with Food and Drug Administration (FDA) and Conformité Européenne (CE) regulatory clearance. We report T<sub>1</sub> measurement repeatability across centers describing sequence, magnet, and vendor performance.<h4>Methods</h4>Phantoms batch-manufactured in August 2015 underwent 2 years of structural imaging, ...[more]

PMID: 32375896

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Project description:Recent innovations in quantitative magnetic resonance imaging (MRI) measurement methods have led to improvements in accuracy, repeatability, and acquisition speed, and have prompted renewed interest to reevaluate the medical value of quantitative T1. The purpose of this study was to determine the bias and reproducibility of T1 measurements in a variety of MRI systems with an eye toward assessing the feasibility of applying diagnostic threshold T1 measurement across multiple clinical sites. We used the International Society of Magnetic Resonance in Medicine/National Institute of Standards and Technology (ISMRM/NIST) system phantom to assess variations of T1 measurements, using a slow, reference standard inversion recovery sequence and a rapid, commonly-available variable flip angle sequence, across MRI systems at 1.5 tesla (T) (two vendors, with number of MRI systems n = 9) and 3 T (three vendors, n = 18). We compared the T1 measurements from inversion recovery and variable flip angle scans to ISMRM/NIST phantom reference values using Analysis of Variance (ANOVA) to test for statistical differences between T1 measurements grouped according to MRI scanner manufacturers and/or static field strengths. The inversion recovery method had minor over- and under-estimations compared to the NMR-measured T1 values at both 1.5 T and 3 T. Variable flip angle measurements had substantially greater deviations from the NMR-measured T1 values than the inversion recovery measurements. At 3 T, the measured variable flip angle T1 for one vendor is significantly different than the other two vendors for most of the samples throughout the clinically relevant range of T1. There was no consistent pattern of discrepancy between vendors. We suggest establishing rigorous quality control procedures for validating quantitative MRI methods to promote confidence and stability in associated measurement techniques and to enable translation of diagnostic threshold from the research center to the entire clinical community.

Project description:Absolute quantification of radiotracer distribution using SPECT/CT imaging is of great importance for dosimetry aimed at personalized radionuclide precision treatment. However, its accuracy depends on many factors. Using phantom measurements, this multi-vendor and multi-center study evaluates the quantitative accuracy and inter-system variability of various SPECT/CT systems as well as the effect of patient size, processing software and reconstruction algorithms on recovery coefficients (RC). METHODS:Five SPECT/CT systems were included: Discovery™ NM/CT 670 Pro (GE Healthcare), Precedence™ 6 (Philips Healthcare), Symbia Intevo™, and Symbia™ T16 (twice) (Siemens Healthineers). Three phantoms were used based on the NEMA IEC body phantom without lung insert simulating body mass indexes (BMI) of 25, 28, and 47 kg/m2. Six spheres (0.5-26.5 mL) and background were filled with 0.1 and 0.01 MBq/mL 99mTc-pertechnetate, respectively. Volumes of interest (VOI) of spheres were obtained by a region growing technique using a 50% threshold of the maximum voxel value corrected for background activity. RC, defined as imaged activity concentration divided by actual activity concentration, were determined for maximum (RCmax) and mean voxel value (RCmean) in the VOI for each sphere diameter. Inter-system variability was expressed as median absolute deviation (MAD) of RC. Acquisition settings were standardized. Images were reconstructed using vendor-specific 3D iterative reconstruction algorithms with institute-specific settings used in clinical practice and processed using a standardized, in-house developed processing tool based on the SimpleITK framework. Additionally, all data were reconstructed with a vendor-neutral reconstruction algorithm (Hybrid Recon™; Hermes Medical Solutions). RESULTS:RC decreased with decreasing sphere diameter for each system. Inter-system variability (MAD) was 16 and 17% for RCmean and RCmax, respectively. Standardized reconstruction decreased this variability to 4 and 5%. High BMI hampers quantification of small lesions (< 10 ml). CONCLUSION:Absolute SPECT quantification in a multi-center and multi-vendor setting is feasible, especially when reconstruction protocols are standardized, paving the way for a standard for absolute quantitative SPECT.

Project description:PURPOSE:To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3?T. METHODS:A T1 phantom with 14 samples was imaged at eight centers with a common inversion-recovery spin-echo (IR-SE) protocol and a variable flip angle (VFA) protocol using seven flip angles, as well as site-specific protocols (VFA with different flip angles, variable repetition time, proton density, and Look-Locker inversion recovery). Factors influencing the accuracy (deviation from reference NMR T1 measurements) and repeatability were assessed using general linear mixed models. Interplatform reproducibility was assessed using coefficients of variation. RESULTS:For the common IR-SE protocol, accuracy (median error across platforms?=?1.4-5.5%) was influenced predominantly by T1 sample (P?<?10-6 ), whereas test-retest repeatability (median error?=?0.2-8.3%) was influenced by the scanner (P?<?10-6 ). For the common VFA protocol, accuracy (median error?=?5.7-32.2%) was influenced by field strength (P?=?0.006), whereas repeatability (median error?=?0.7-25.8%) was influenced by the scanner (P?<?0.0001). Interplatform reproducibility with the common VFA was lower at 3?T than 1.5?T (P?=?0.004), and lower than that of the common IR-SE protocol (coefficient of variation 1.5T: VFA/IR-SE?=?11.13%/8.21%, P?=?0.028; 3?T: VFA/IR-SE?=?22.87%/5.46%, P?=?0.001). Among the site-specific protocols, Look-Locker inversion recovery and VFA (2-3 flip angles) protocols showed the best accuracy and repeatability (errors?<?15%). CONCLUSIONS:The VFA protocols with 2 to 3 flip angles optimized for different applications achieved acceptable balance of extensive spatial coverage, accuracy, and repeatability in T1 quantification (errors?<?15%). Further optimization in terms of flip-angle choice for each tissue application, and the use of B1 correction, are needed to improve the robustness of VFA protocols for T1 mapping. Magn Reson Med 79:2564-2575, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Project description:BackgroundA calibration phantom-based method has been developed for predicting small lung nodule volume measurement bias and precision that is specific to a particular computed tomography (CT) scanner and acquisition protocol.MethodsThe approach involves CT scanning a simple reference object with a specific acquisition protocol, analyzing the scan to estimate the fundamental imaging properties of the CT acquisition system, generating numerous simulated images of a target geometry using the fundamental imaging properties, measuring the simulated images with a standard nodule volume segmentation algorithm, and calculating bias and precision performance statistics from the resulting volume measurements. We evaluated the ability of this approach to predict volume measurement bias and precision of Teflon spheres (diameters =4.76, 6.36, and 7.94 mm) placed within an anthropomorphic chest phantom when using 3M Scotch Magic™ tape as the reference object. CT scanning of the spheres was performed with 0.625, 1.25, and 2.5 mm slice thickness and spacing.ResultsThe study demonstrated good agreement between predicted volumetric performance and observed volume measurement performance for both volumetric measurement bias and precision. The predicted and observed volume mean for all slice thicknesses was found to be 28% and 13% lower on average than the manufactured sphere volume, respectively. When restricted to 0.625 and 1.25 mm slice thickness scans, which are recommended for small lung nodule volume measurement, we found that the difference between predicted and observed volume coefficient of variation was less than 1.0 %. The approach also showed a resilience to varying CT image acquisition protocols, a critical capability when deploying in a real-world clinical setting.ConclusionsThis is the first report of a calibration phantom-based method's ability to predict both small lung nodule volume measurement bias and precision. Volume measurement bias and precision for small lung nodules can be predicted using simple low-cost reference objects to estimate fundamental CT image characteristics and modeling and simulation techniques. The approach demonstrates an improved method for predicting task specific, clinically relevant measurement performance using advanced and fully automated image analysis techniques and low-cost reference objects.

Project description:The National Comprehensive Cancer Control Program (NCCCP) performance measurement system seeks to understand both the processes that funded programs undertake with their respective coalitions to implement the objectives of their cancer plans and the outcomes of those efforts.To identify areas of achievement and technical assistance needs of NCCCP awardees.Program performance was assessed through surveys completed by program directors on performance indicators in 2009 and 2010 and queries from a Web-based management information system in 2011 and 2012.Programs funded by the Centers for Disease Control and Prevention's NCCCP.Sixty-nine programs.The key performance measures assessed were inclusion of diverse partners and key sectors in cancer coalitions, partners' involvement in activities, receiving in-kind resources from partners, using evidence-based interventions and data for setting priorities, conducting program evaluation, using community- or organization-level strategies to address cancer control efforts, and demonstrating progress toward achieving health outcomes.Most programs reported having active coalitions that represent diverse organizational sectors. Nearly all programs routinely assess the burden of cancer. In-kind resources to implement activities peaked at $64 716 in the second year of a 5-year funding cycle and declined in subsequent project years. By year 3, more than 70% of programs reported having an evaluation plan. While programs reported that nearly two-thirds of their interventions were evidence-based, some programs implemented non-evidence-based interventions. A majority of programs successfully used at least 1 community- or organization-level change strategy. However, many programs did not incorporate objectives linked to health outcomes as they reported progress in implementing interventions.While NCCCP programs were strong at building and maintaining infrastructure, some programs may need additional technical assistance to increase the adoption of evidence-based interventions, develop solid and responsive evaluation plans, and better link efforts to population-based measures that demonstrate impact toward reducing the burden of cancer.

Project description:ObjectivesTo investigate the effect of the phantom-based correction method for standardizing myocardial native T1 and extracellular volume fraction (ECV) in healthy subjects.MethodsSeventy-one healthy asymptomatic adult (≥ 20 years) volunteers of five different age groups (34 men and 37 women, 45.5 ± 15.5 years) were prospectively enrolled in three academic hospitals. Cardiac MRI including Modified Look - Locker Inversion recovery T1 mapping sequence was performed using a 3-Tesla system with a different type of scanner for each hospital. Native T1 and ECV were measured in the short-axis T1 map and analyzed for mean values of the 16 entire segments. The myocardial T1 value of each subject was corrected based on the site-specific equation derived from the T1 Mapping and ECV Standardization phantom. The global native T1 and ECV were compared between institutions before and after phantom-based correction, and the variation in native T1 and ECV among institutions was assessed using a coefficient of variation (CoV).ResultsThe global native T1 value significantly differed between the institutions (1198.7 ± 32.1 ms, institution A; 1217.7 ± 39.9 ms, institution B; 1232.7 ± 31.1 ms, institution C; p = 0.002), but the mean ECV did not (26.6-27.5%, p = 0.355). After phantom-based correction, the global native T1 and ECV were 1289.7 ± 32.4 ms and 25.0 ± 2.7%, respectively, and CoV for native T1 between the three institutions decreased from 3.0 to 2.5%. The corrected native T1 value did not significantly differ between institutions (1284.5 ± 31.5 ms, institution A; 1296.5 ± 39.1 ms, institution B; 1291.3 ± 29.3 ms, institution C; p = 0.440), and neither did the ECV (24.4-25.9%, p = 0.078).ConclusionsThe phantom-based correction method can provide standardized reference T1 values in healthy subjects.Key points• After phantom-based correction, the global native T1 of 16 entire myocardial segments on 3-T cardiac MRI is 1289.4 ± 32.4 ms, and the extracellular volume fraction was 25.0 ± 2.7% for healthy subjects. • After phantom - based correction was applied, the differences in the global native T1 among institutions became insignificant, and the CoV also decreased from 3.0 to 2.5%.

Dataset Information

T1 mapping performance and measurement repeatability: results from the multi-national T1 mapping standardization phantom program (T1MES).

Publications

T<sub>1</sub> mapping performance and measurement repeatability: results from the multi-national T<sub>1</sub> mapping standardization phantom program (T1MES).

Similar Datasets

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