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Abstract Background Little is known about the frequency with which different combinations of phytochemicals (chemovars) arise in Cannabis flower or whether common chemovars are associated with distinct pharmacodynamics and patient health outcomes. This study created a clinically relevant, user-friendly, scalable chemovar indexing system summarizing primary cannabinoid and terpene contents and tested whether the most frequently consumed chemovars differ in their treatment effectiveness and experienced side effects. Methods Between 09/10/2016 and 03/11/2021, 204 people used the freely available, educational mobile software application, Releaf App, to record 6309 real-time consumption sessions using 633 distinct Cannabis flower products, unique at the user level, with terpene and cannabinoid potency information. The indexing system is based on retrospective data analysis of the products’ primary and secondary terpene contents and tetrahydrocannabinol (THC) and cannabidiol (CBD) potencies and yielded a total of 478 distinct chemovars. Analyses of covariances (ANCOVAs) were used to compare symptom levels and side effects experienced across the five most common chemovars before and after cannabis consumption for app users overall and for those treating chronic pain and depression or anxiety. Results Examination of the five most frequently consumed chemovars showed significant differences in symptom treatment effectiveness for chronic pain and for depression and anxiety (ps

Introduction: We measure for the first time the associations between subjective patient experiences of feeling “high” and treatment outcomes during real-time Cannabis flower consumption sessions.Methods: Our study uses data from the mobile health app, Releaf App™, through which 1,882 people tracked the effects of Cannabis flower on a multitude of health conditions during 16,480 medical cannabis self-administration sessions recorded between 6/5/2016 and 3/11/2021. Session-level reported information included plant phenotypes, modes of administration, potencies, baseline and post-administration symptom intensity levels, total dose used, and real-time side effect experiences.Results: Patients reported feeling high in 49% of cannabis treatment sessions. Using individual patient-level fixed effects regression models and controlling for plant phenotype, consumption mode, tetrahydrocannabinol (THC) and cannabidiol (CBD) potencies, dose, and starting symptom level, our results show that, as compared to sessions in which individuals did not report feeling high, reporting feeling high was associated with a 7.7% decrease in symptom severity from a mean reduction of −3.82 on a 0 to 10 analog scale (coefficient = −0.295, p < 0.001) with evidence of a 14.4 percentage point increase (p < 0.001) in negative side effect reporting and a 4.4 percentage point (p < 0.01) increase in positive side effect reporting. Tetrahydrocannabinol (THC) levels and dose were the strongest statistical predictors of reporting feeling high, while the use of a vaporizer was the strongest inhibitor of feeling high. In symptom-specific models, the association between feeling high and symptom relief remained for people treating pain (p < 0.001), anxiety (p < 0.001), depression (p < 0.01) and fatigue (p < 0.01), but was insignificant, though still negative, for people treating insomnia. Although gender and pre-app cannabis experience did not appear to affect the relationship between high and symptom relief, the relationship was larger in magnitude and more statistically significant among patients aged 40 or less.Discussion: The study results suggest clinicians and policymakers should be aware that feeling high is associated with improved symptom relief but increased negative side effects, and factors such as mode of consumption, product potency, and dose can be used to adjust treatment outcomes for the individual patient.

Objectives: Many annual, nationally representative US surveys that assess cannabis use do not collect information on product characteristics despite varying health risks and benefits. Capitalizing on a rich dataset of primarily medical users, the purpose of this study was to describe the degree of potential misclassification in clinically relevant cannabis use measures when primary mode of use is recorded but not product type. Methods: Analyses consider user-level data from the Releaf App™ database on product types, consumption modes, and potencies in a non-nationally representative sample of 26,322 cannabis administration sessions occurring in 2018, across 3,258 users. Proportions, means, and 95% confidence intervals were calculated and compared across products and modes. Results: Primary consumption modes were smoking (47.1%), vaping (36.5%), and eating/drinking (10.4%), with 22.7% of users reporting multiple modes of use. Moreover, mode of use did not signify a single product type: users reported vaping both flower (41.3%) and concentrates (68.7%). Of those who smoked cannabis, 8.1% reported smoking concentrates. Concentrates averaged 3.4 times higher tetrahydrocannabinol (THC) potency and 3.1 times higher cannabidiol (CBD) potency than flower. Conclusions: Cannabis consumers employ multiple consumption modes, and product type cannot be inferred from mode of use. With THC potencies markedly higher in concentrates, these findings underscore the importance of including information on cannabis product types and mode of use in surveillance surveys. Clinicians and policymakers need these data to inform treatment decisions and assess cannabis policies’ implications for population health.

Objectives: We measure for the first time how commercially available Cannabis flower products affect feelings of fatigue. Methods: A total of 1,224 people recorded 3,922 Cannabis flower self-administration sessions between June 6, 2016, and August 7, 2019, using the Releaf App. Usage sessions included real-time subjective changes in fatigue intensity levels prior to and following Cannabis consumption, Cannabis flower characteristics (labeled phenotype, cannabinoid potency levels), combustion method, and any potential experienced side effects. Results: On average, 91.94% of people experienced decreased fatigue following consumption with an average symptom intensity reduction of 3.48 points on a 0–10 visual analog scale (SD = 2.70, d = 1.60, p < 0.001). While labeled plant phenotypes (“C. indica,” “C. sativa,” or “hybrid”) did not differ in symptom relief, people that used joints to combust the flower reported greater symptom relief than pipe or vaporizer users. Across cannabinoid levels, tetrahydrocannabinol, and cannabidiol levels were generally not associated with changes in symptom intensity levels. Cannabis use was associated with several negative side effects that correspond to increased feelings of fatigue (e.g., feeling unmotivated, couch-locked) among a minority of users (

Objective: A relationship between T1ρ relaxation time and glycosaminoglycan (GAG) content has been demonstrated in chemically degraded bovine cartilage, but has not been demonstrated with quantitative biochemistry in human cartilage. A relationship has also been established between T2 relaxation time in cartilage and osteoarthritis (OA) severity. We hypothesized that T1ρ relaxation time would be associated with GAG content in human cartilage with normal T2 relaxation times.Methods: T2 relaxation time, T1ρ relaxation time, and glycosaminoglycan as a percentage of wet weight (sGAG) were measured for top and bottom regions at 7 anatomical locations in 21 human cadaver patellae. For our analysis, T2 relaxation time was classified as normal or elevated based on a threshold defined by the mean plus one standard deviation of the T2 relaxation time for all samples.Results: In the normal T2 relaxation time subset, T1ρ relaxation time correlated with sGAG content in the full-thickness and bottom regions, but only marginally in the top region alone. sGAG content decreased significantly with age in all regions.Conclusion: In the subset of cartilage specimens with normal T2 relaxation time, T1ρ relaxation time was inversely associated with sGAG content, as hypothesized. A predictive model, which accounts for T2 relaxation time and the effects of age, might be able to determine longitudinal trends in GAG content in the same person based on T1ρ relaxation time maps. [ABSTRACT FROM AUTHOR]

Background: The Releaf AppTM mobile software application (app) data was used to measure self-reported effectiveness and side effects of medical cannabis used under naturalistic conditions.Methods: Between 5/03/2016 and 12/16/2017, 2,830 Releaf AppTM users completed 13,638 individual sessions self-administering medical cannabis and indicated their primary health symptom severity rating on an 11-point (0–10) visual analog scale in real-time prior to and following cannabis consumption, along with experienced side effects.Results: Releaf AppTM responders used cannabis to treat myriad health symptoms, the most frequent relating to pain, anxiety, and depressive conditions. Significant symptom severity reductions were reported for all the symptom categories, with mean reductions between 2.8 and 4.6 points (ds ranged from 1.29–2.39, ps < 0.001). On average, higher pre-dosing symptom levels were associated with greater reported symptom relief, and users treating anxiety or depression-related symptoms reported significantly more relief (ps < 0.001) than users with pain symptoms. Of the 42 possible side effects, users were more likely to indicate and showed a stronger correlation between symptom relief and experiences of positive (94% of sessions) or a context-specific side effects (76%), whereas negative side effects (60%) were associated with lessened, yet still significant symptom relief and were more common among patients treating a depressive symptom relative to patients treating anxiety and pain-related conditions.Conclusion: Patient-managed cannabis use is associated with clinically significant improvements in self-reported symptom relief for treating a wide range of health conditions, along with frequent positive and negative side effects.

Background: We use a mobile software application (app) to measure for the first time, which fundamental characteristics of raw, natural medical Cannabis flower are associated with changes in perceived insomnia under naturalistic conditions. Methods: Four hundred and nine people with a specified condition of insomnia completed 1056 medical cannabis administration sessions using the Releaf AppTM educational software during which they recorded real-time ratings of self-perceived insomnia severity levels prior to and following consumption, experienced side effects, and product characteristics, including combustion method, cannabis subtypes, and/or major cannabinoid contents of cannabis consumed. Within-user effects of different flower characteristics were modeled using a fixed effects panel regression approach with standard errors clustered at the user level. Results: Releaf AppTM users showed an average symptom severity reduction of −4.5 points on a 0–10 point visual analogue scale (SD = 2.7, d = 2.10, p < 0.001). Use of pipes and vaporizers was associated with greater symptom relief and more positive and context-specific side effects as compared to the use of joints, while vaporization was also associated with lower negative effects. Cannabidiol (CBD) was associated with greater statistically significant symptom relief than tetrahydrocannabinol (THC), but the cannabinoid levels generally were not associated with differential side effects. Flower from C. sativa plants was associated with more negative side effects than flower from C. indica or hybrid plant subtypes. Conclusions: Consumption of medical Cannabis flower is associated with significant improvements in perceived insomnia with differential effectiveness and side effect profiles, depending on the product characteristics.

Objective: This work presents an automated quality control (QC) system within quantitative MRI (qMRI) workflows. By leveraging the ISMRM/NIST quantitative MRI system phantom, we establish an open-source pipeline for rapid, repeatable, and accurate validation and stability tracking of sequence quantification performance across diverse clinical settings., Materials and Methods: A microservice-based QC system for automated vial segmentation from quantitative maps was developed and tested across various MRF acquisition and protocol designs, with reports generated and returned to the scanner in real time., Results: The system demonstrated consistent and repeatable value segmentation and reporting, successfully extracted all 252 T1 and T2 vial samples tested. Values extracted from the same sequence were found to be repeatable with 0.09% ± 1.23% and - 0.26% ± 2.68% intersession error, respectively., Discussion: By providing real-time quantification performance assessment, this easily deployable automated QC approach streamlines sequence validation and long-term performance monitoring, vital for the broader acceptance of qMRI as a standard component of clinical protocols., (© 2024. The Author(s), under exclusive licence to European Society for Magnetic Resonance in Medicine and Biology (ESMRMB).)

Purpose: To compare T1 and T2 measurements across commercial and prototype 0.55T MRI systems in both phantom and healthy participants using the same vendor-neutral pulse sequences, reconstruction, and analysis methods., Methods: Standard spin echo measurements and abbreviated protocol measurements of T1, B1, and T2 were made on two prototype 0.55 T systems and two commercial 0.55T systems using an ISMRM/NIST system phantom. Additionally, five healthy participants were imaged at each system using the abbreviated protocol for T1, B1, and T2 measurement. The phantom measurements were compared to NMR-based reference measurements to determine accuracy, and both phantom and in vivo measurements were compared to assess reproducibility and differences between the prototype and commercial systems., Results: Vendor-neutral sequences were implemented across all four systems, and the code for pulse sequences and reconstruction is freely available. For participants, there was no difference in the mean T1 and T2 relaxation times between the prototype and commercial systems. In the phantom, there were no significant differences between the prototype and commercial systems for T1 and T2 measurements using the abbreviated protocol., Conclusion: Quantitative T1 and T2 measurements at 0.55T in phantom and healthy participants are not statistically different across the prototype and commercial systems., (© 2024 International Society for Magnetic Resonance in Medicine. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Presenting quantitative data using non-standardized color maps potentially results in unrecognized misinterpretation of data. Clinically meaningful color maps should intuitively and inclusively represent data without misleading interpretation. Uniformity of the color gradient for color maps is critically important. Maximal color and lightness contrast, readability for color vision-impaired individuals, and recognizability of the color scheme are highly desirable features. This article describes the use of color maps in five key quantitative MRI techniques: relaxometry, diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE)-MRI, MR elastography (MRE), and water-fat MRI. Current display practice of color maps is reviewed and shortcomings against desirable features are highlighted. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 2., (© 2024 The Author(s). Journal of Magnetic Resonance Imaging published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

In this paper, we review the value of phantoms for body MRI in the context of their uses for quantitative MRI methods research, clinical trials, and clinical imaging. Certain uses of phantoms are common throughout the body MRI community, including measuring bias, assessing reproducibility, and training. In addition to these uses, phantoms in body MRI methods research are used for novel methods development and the design of motion compensation and mitigation techniques. For clinical trials, phantoms are an essential part of quality management strategies, facilitating the conduct of ethically sound, reliable, and regulatorily compliant clinical research of both novel MRI methods and therapeutic agents. In the clinic, phantoms are used for development of protocols, mitigation of cost, quality control, and radiotherapy. We briefly review phantoms developed for quantitative body MRI, and finally, we review open questions regarding the most effective use of a phantom for body MRI., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Rumination is a significant risk factor for psychopathology in adolescent girls and is associated with heightened and prolonged physiological arousal following social rejection. However, no study has examined how rumination relates to neural responses to social rejection in adolescent girls; thus, the current study aimed to address this gap. Adolescent girls (N = 116; ages 16.95-19.09) self-reported on their rumination tendency and completed a social evaluation fMRI task where they received fictitious feedback (acceptance, rejection) from peers they liked or disliked. Rejection-related neural activity and subgenual anterior cingulate cortex (sgACC) connectivity were regressed on rumination, controlling for rejection sensitivity and depressive symptoms. Rumination was associated with distinctive neural responses following rejection from liked peers including increased neural activity in the precuneus, inferior parietal gyrus, dorsolateral prefrontal cortex, and supplementary motor area (SMA) and reduced sgACC connectivity with multiple regions including medial prefrontal cortex, precuneus and ventrolateral prefrontal cortex. Greater precuneus and SMA activity mediated the effect of rumination on slower response time to report emotional state after receiving rejection from liked peers. These findings provide clues for distinctive cognitive processes (e.g., mentalizing, conflict processing, memory encoding) following the receipt of rejection in girls with high levels of rumination., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

In March 2022, the first ISMRM Workshop on Low-Field MRI was held virtually. The goals of this workshop were to discuss recent low field MRI technology including hardware and software developments, novel methodology, new contrast mechanisms, as well as the clinical translation and dissemination of these systems. The virtual Workshop was attended by 368 registrants from 24 countries, and included 34 invited talks, 100 abstract presentations, 2 panel discussions, and 2 live scanner demonstrations. Here, we report on the scientific content of the Workshop and identify the key themes that emerged. The subject matter of the Workshop reflected the ongoing developments of low-field MRI as an accessible imaging modality that may expand the usage of MRI through cost reduction, portability, and ease of installation. Many talks in this Workshop addressed the use of computational power, efficient acquisitions, and contemporary hardware to overcome the SNR limitations associated with low field strength. Participants discussed the selection of appropriate clinical applications that leverage the unique capabilities of low-field MRI within traditional radiology practices, other point-of-care settings, and the broader community. The notion of "image quality" versus "information content" was also discussed, as images from low-field portable systems that are purpose-built for clinical decision-making may not replicate the current standard of clinical imaging. Speakers also described technical challenges and infrastructure challenges related to portability and widespread dissemination, and speculated about future directions for the field to improve the technology and establish clinical value., (© 2023 International Society for Magnetic Resonance in Medicine. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

We have investigated the efficacy of superparamagnetic iron oxide nanoparticles (SPIONs) as positive T 1 contrast agents for low-field magnetic resonance imaging (MRI) at 64 millitesla (mT). Iron oxide-based agents, such as the FDA-approved ferumoxytol, were measured using a variety of techniques to evaluate T 1 contrast at 64 mT. Additionally, we characterized monodispersed carboxylic acid-coated SPIONs with a range of diameters (4.9-15.7 nm) in order to understand size-dependent properties of T 1 contrast at low-field. MRI contrast properties were measured using 64 mT MRI, magnetometry, and nuclear magnetic resonance dispersion (NMRD). We also measured MRI contrast at 3 T to provide comparison to a standard clinical field strength. SPIONs have the capacity to perform well as T 1 contrast agents at 64 mT, with measured longitudinal relaxivity (r 1 ) values of up to 67 L mmol -1  s -1 , more than an order of magnitude higher than corresponding r 1 values at 3 T. The particles exhibit size-dependent longitudinal relaxivities and outperform a commercial Gd-based agent (gadobenate dimeglumine) by more than eight-fold at physiological temperatures. Additionally, we characterize the ratio of transverse to longitudinal relaxivity, r 2 /r 1 and find that it is ~ 1 for the SPION based agents at 64 mT, indicating a favorable balance of relaxivities for T 1 -weighted contrast imaging. We also correlate the magnetic and structural properties of the particles with models of nanoparticle relaxivity to understand generation of T 1 contrast. These experiments show that SPIONs, at low fields being targeted for point-of-care low-field MRI systems, have a unique combination of magnetic and structural properties that produce large T 1 relaxivities., (© 2023. The Author(s).)

Existing magnetic resonance imaging (MRI) reference objects, or phantoms, are typically constructed from simple liquid or gel solutions in containers with specific geometric configurations to enable multi-year stability. However, there is a need for phantoms that better mimic the human anatomy without barriers between the tissues. Barriers result in regions without MRI signal between the different tissue mimics, which is an artificial image artifact. We created an anatomically representative 3D structure of the brain that mimicked the T1 and T2 relaxation properties of white and gray matter at 3 T. While the goal was to avoid barriers between tissues, the 3D printed barrier between white and gray matter and other flaws in the construction were visible at 3 T. Stability measurements were made using a portable MRI system operating at 64 mT, and T2 relaxation time was stable from 0 to 22 weeks. The phantom T1 relaxation properties did change from 0 to 10 weeks; however, they did not substantially change between 10 weeks and 22 weeks. The anthropomorphic phantom used a dissolvable mold construction method to better mimic anatomy, which worked in small test objects. The construction process, though, had many challenges. We share this work with the hope that the community can build on our experience., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Objective: To measure healthy brain [Formula: see text] and [Formula: see text] relaxation times at 0.064 T., Materials and Methods: [Formula: see text] and [Formula: see text] relaxation times were measured in vivo for 10 healthy volunteers using a 0.064 T magnetic resonance imaging (MRI) system and for 10 test samples on both the MRI and a separate 0.064 T nuclear magnetic resonance (NMR) system. In vivo [Formula: see text] and [Formula: see text] values are reported for white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) for automatic segmentation regions and manual regions of interest (ROIs)., Results: [Formula: see text] sample measurements on the MRI system were within 10% of the NMR measurement for 9 samples, and one sample was within 11%. Eight [Formula: see text] sample MRI measurements were within 25% of the NMR measurement, and the two longest [Formula: see text] samples had more than 25% variation. Automatic segmentations generally resulted in larger [Formula: see text] and [Formula: see text] estimates than manual ROIs., Discussion: [Formula: see text] and [Formula: see text] times for brain tissue were measured at 0.064 T. Test samples demonstrated accuracy in WM and GM ranges of values but underestimated long [Formula: see text] in the CSF range. This work contributes to measuring quantitative MRI properties of the human body at a range of field strengths., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Objective: Temperature controlled T 1 and T 2 relaxation times are measured on NiCl 2 and MnCl 2 solutions from the ISMRM/NIST system phantom at low magnetic field strengths of 6.5 mT, 64 mT and 550 mT., Materials and Methods: The T 1 and T 2 were measured of five samples with increasing concentrations of NiCl 2 and five samples with increasing concentrations of MnCl 2 . All samples were scanned at 6.5 mT, 64 mT and 550 mT, at sample temperatures ranging from 10 °C to 37 °C., Results: The NiCl 2 solutions showed little change in T 1 and T 2 with magnetic field strength, and both relaxation times decreased with increasing temperature. The MnCl 2 solutions showed an increase in T 1 and a decrease in T 2 with increasing magnetic field strength, and both T 1 and T 2 increased with increasing temperature., Discussion: The low field relaxation rates of the NiCl 2 and MnCl 2 arrays in the ISMRM/NIST system phantom are investigated and compared to results from clinical field strengths of 1.5 T and 3.0 T. The measurements can be used as a benchmark for MRI system functionality and stability, especially when MRI systems are taken out of the radiology suite or laboratory and into less traditional environments., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

T1 relaxation times of the 14 T1 phantom spheres that make up the standard International Society for Magnetic Resonance in Medicine (ISMRM)/National Institute of Standards and Technology (NIST) system phantom are reported at 7 T. T1 values of six of the 14 T1 spheres at 7 T (with T1 > 270 ms) have been reported previously, but, to the best of our knowledge, not all of the T1s of the 14 T1 spheres at 7 T have been reported before. Given the increasing number of 7-T MRI systems in clinical settings and the increasing need for T1 phantoms that cover a wide range of T1 relaxation times to evaluate rapid T1 mapping techniques at 7 T, it is of high interest to obtain accurate T1 values for all the ISMRM/NIST T1 spheres at 7 T. In this work, T1 relaxation time was measured on a 7-T MRI scanner using an inversion-recovery spin-echo pulse sequence and derived by curve fitting to a signal equation that exhibits insensitivity to B 1 + inhomogeneity. Day-to-day reproducibility was within 0.4% and differences between two different RF coils within 1.5%. T1s of a subset of the 14 spheres were also measured by NMR at 7 T for comparison, and the T1 results were consistent between the MRI and NMR measurements. T1 measurements performed at 3 T on the same 14 spheres using the same sequence and fitting method yielded good agreement (mean percentage difference of -0.4%) with the reference T1 values available from the NIST, reflecting the accuracy of the reported technique despite being without the standard phantom housing. We found that the T1 values of all 14 NiCl 2 spheres are consistently lower at 7 T than at 3 T. Although our results were well reproduced, this study represents initial work to quantify the 7-T T1 values of all 14 NIST T1 spheres outside of the standard housing and does not warrant reproducibility of the ISMRM/NIST system phantom as a whole. A future study to assess the T1 values of a version of the ISMRM/NIST system phantom that fits inside typical commercial coils at 7 T will be very helpful. Nonetheless, the details on our acquisition and curve-fitting methods reported here allow the T1 measurements to be reproduced elsewhere. The T1 values of all 14 spheres reported here will be valuable for the development of quantitative MR fingerprinting and rapid T1 mapping for a large variety of research projects, not only in neuroimaging but also in body MRI, musculoskeletal MRI, and gadolinium contrast-enhanced MRI, each of which is concerned with much shortened T1., (© 2022 John Wiley & Sons Ltd.)

Introduction: A long T 2 relaxation time can reflect oedema, and myocardial inflammation when combined with increased plasma troponin levels. Cardiovascular magnetic resonance (CMR) T 2 mapping therefore has potential to provide a key diagnostic and prognostic biomarkers. However, T 2 varies by scanner, software, and sequence, highlighting the need for standardization and for a quality assurance system for T 2 mapping in CMR., Aim: To fabricate and assess a phantom dedicated to the quality assurance of T 2 mapping in CMR., Method: A T 2 mapping phantom was manufactured to contain 9 T 1 and T 2 (T 1 |T 2 ) tubes to mimic clinically relevant native and post-contrast T 2 in myocardium across the health to inflammation spectrum (i.e., 43-74 ms) and across both field strengths (1.5 and 3 T). We evaluated the phantom's structural integrity, B 0 and B 1 uniformity using field maps, and temperature dependence. Baseline reference T 1 |T 2 were measured using inversion recovery gradient echo and single-echo spin echo (SE) sequences respectively, both with long repetition times (10 s). Long-term reproducibility of T 1 |T 2 was determined by repeated T 1 |T 2 mapping of the phantom at baseline and at 12 months., Results: The phantom embodies 9 internal agarose-containing T 1 |T 2 tubes doped with nickel di-chloride (NiCl 2 ) as the paramagnetic relaxation modifier to cover the clinically relevant spectrum of myocardial T 2 . The tubes are surrounded by an agarose-gel matrix which is doped with NiCl 2 and packed with high-density polyethylene (HDPE) beads. All tubes at both field strengths, showed measurement errors up to ≤ 7.2 ms [< 14.7%] for estimated T 2 by balanced steady-state free precession T 2 mapping compared to reference SE T 2 with the exception of the post-contrast tube of ultra-low T 1 where the deviance was up to 16 ms [40.0%]. At 12 months, the phantom remained free of air bubbles, susceptibility, and off-resonance artifacts. The inclusion of HDPE beads effectively flattened the B 0 and B 1 magnetic fields in the imaged slice. Independent temperature dependency experiments over the 13-38 °C range confirmed the greater stability of shorter vs longer T 1 |T 2 tubes. Excellent long-term (12-month) reproducibility of measured T 1 |T 2 was demonstrated across both field strengths (all coefficients of variation < 1.38%)., Conclusion: The T 2 mapping phantom demonstrates excellent structural integrity, B 0 and B 1 uniformity, and reproducibility of its internal tube T 1 |T 2 out to 1 year. This device may now be mass-produced to support the quality assurance of T 2 mapping in CMR., (© 2023. The Author(s).)

Background: To date, the accuracy and variability of diffusion-weighted MRI (DW-MRI) metrics have been reported in a limited number of scanner/protocol/coil combinations., Purpose: To evaluate the reproducibility of DW-MRI estimates across multiple scanners and DW-MRI protocols and to assess the effects of using an 8-channel vs. 16-channel breast coil in a breast phantom., Study Type: Prospective., Phantom: Breast phantom containing tubes of water and differing polyvinylpyrrolidone (PVP) concentrations with apparent diffusion coefficients (ADCs) matching breast tissue., Field Strength/sequence: 3 T (three standard and one wide bore), three DW-MRI single-shot echo planar imaging protocols of varying acquired spatial resolution., Assessment: Accuracy of estimated ADCs was assessed using percent differences (PD) relative to nuclear magnetic resonance spectroscopy-derived reference values. Coefficients of variation (CV) were calculated to determine variation across scanners. CVs based on the median standard deviation (CV M ) were used to evaluate tube-specific dispersion using 8- or 16-channel coils at a single scanner. ADCs of PVP-containing tubes were additionally normalized by the median water tube ADC to account for temperature effects., Statistical Tests: Two-way repeated measures analysis of variance and post hoc tests were used to evaluate differences in ADC, CV, and CV M across scanners and protocols (α = 0.05)., Results: ADCs were within 11% (interquartile range [IQR] 7%) of reference values and significantly improved to 2% (IQR 7%) after normalization to an internal water reference. Normalization significantly reduced interscanner variability of ADC estimates from 7% to 4%. DW-MRI protocol did not affect ADC accuracy; however, the clinical and higher-resolution clinical protocols resulted in the greatest (9%) and least (6%) interscanner variability, respectively. The 8- and 16-channel receive coils yielded similar accuracy (PD: 12% vs. 16%) and precision (CV M : 2.7% vs. 2.9%)., Data Conclusion: Normalization by an internal reference improved interscanner ADC reproducibility. High-resolution protocols yielded comparably accurate and significantly less variable ADCs compared to a clinical standard protocol., Evidence Level: 2 TECHNICAL EFFICACY: Stage 1., (© 2022 International Society for Magnetic Resonance in Medicine. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Anhedonia is a transdiagnostic symptom of psychopathology that includes diminished positive emotions and anticipation and enjoyment of reward, with particular salience during adolescence. However, the construct validity of anhedonia dimensions is not well established, thus limiting operationalization and generalization of the construct. We applied exploratory and confirmatory factor analyses to identify latent dimensions of anhedonia across four commonly used self-report measures covering different facets of anhedonic experience within a nonclinical sample of female adolescents across two waves of data collection ( N = 173, M age = 19.25; N = 147, M age = 20.23). Factor analyses yielded a two-factor model with a physical anhedonia factor emphasizing enjoyment from physical sensations and a social anhedonia factor focusing on emotional connections with other people. These results have implications for the measurement of anhedonia in women's emotional well-being and mental health research, including research designed to identify facets of anhedonia that predict the onset, severity, and persistence of psychopathology. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

This review on brain multiparametric quantitative MRI (MP-qMRI) focuses on the primary subset of quantitative MRI (qMRI) parameters that represent the mobile ("free") and bound ("motion-restricted") proton pools. Such primary parameters are the proton densities, relaxation times, and magnetization transfer parameters. Diffusion qMRI is also included because of its wide implementation in complete clinical MP-qMRI application. MP-qMRI advances were reviewed over the past 2 decades, with substantial progress observed toward accelerating image acquisition and increasing mapping accuracy. Areas that need further investigation and refinement are identified as follows: (a) the biologic underpinnings of qMRI parameter values and their changes with age and/or disease and (b) the theoretical limitations implicitly built into most qMRI mapping algorithms that do not distinguish between the different spatial scales of voxels versus spin packets, the central physical object of the Bloch theory. With rapidly improving image processing techniques and continuous advances in computer hardware, MP-qMRI has the potential for implementation in a wide range of clinical applications. Currently, three emerging MP-qMRI applications are synthetic MRI, macrostructural qMRI, and microstructural tissue modeling., (© RSNA, 2022.)

Purpose: To assess the technical performance of the apparent diffusion coefficient (ADC) on a dedicated 3T radiotherapy scanner, using a standardized phantom and sequences. Investigations into factors that could impact the technical performance of ADC in the clinic were also completed, including changing the slice-encoded imaging direction and the reference sample ADC value., Methods: ADC acquisitions were performed monthly on an isotropic diffusion phantom over 1 year. Measurements of ADC %bias, coefficients of variation for short-/long-term repeatability and precision (CV ST /CV LT and CV P ), and b-value dependency (Dep b ) were calculated. The measurements were then assessed according to the Quantitative Imaging Biomarker Alliance (QIBA) Diffusion Profile specifications., Results: The average of all measurements over the year was within Profile recommended ranges. This included when testing was performed in different imaging directions, and on samples that had different ADC reference values (0.4-1.1 μm 2 /ms). Results in the axial plane for the central water vial included a bias of +0.05%, CV ST /CV LT /CV P  = 0.1%/ 0.9%/0.4% and Dep b  = 0.4%., Conclusions: The technical performance of ADC on a radiotherapy dedicated MRI scanner over the course of 12 months was considered conformant to the QIBA Profile. Quantifying these metrics and factors that may affect the performance is essential in progressing the use of ADC clinically: ensuring that the observed change of ADC in a tissue is due to a physiological response and not measurement variability., (© 2022 The Authors. Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)

Image quantitation methods including quantitative MRI, multiparametric MRI, and radiomics offer great promise for clinical use. However, many of these methods have limited clinical adoption, in part due to issues of generalizability, that is, the ability to translate methods and models across institutions. Researchers can assess generalizability through measurement of repeatability and reproducibility, thus quantifying different aspects of measurement variance. In this article, we review the challenges to ensuring repeatability and reproducibility of image quantitation methods as well as present strategies to minimize their variance to enable wider clinical implementation. We present possible solutions for achieving clinically acceptable performance of image quantitation methods and briefly discuss the impact of minimizing variance and achieving generalizability towards clinical implementation and adoption., (© 2021 American Association of Physicists in Medicine. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

On behalf of the International Society for Magnetic Resonance in Medicine (ISMRM) Quantitative MR Study Group, this article provides an overview of considerations for the development, validation, qualification, and dissemination of quantitative MR (qMR) methods. This process is framed in terms of two central technical performance properties, i.e., bias and precision. Although qMR is confounded by undesired effects, methods with low bias and high precision can be iteratively developed and validated. For illustration, two distinct qMR methods are discussed throughout the manuscript: quantification of liver proton-density fat fraction, and cardiac T 1 . These examples demonstrate the expansion of qMR methods from research centers toward widespread clinical dissemination. The overall goal of this article is to provide trainees, researchers, and clinicians with essential guidelines for the development and validation of qMR methods, as well as an understanding of necessary steps and potential pitfalls for the dissemination of quantitative MR in research and in the clinic., (© 2021 International Society for Magnetic Resonance in Medicine.)

The coronavirus disease 2019 (COVID-19) pandemic led to the need for tracking of physical contacts and potential exposure to disease. Traditional contact tracing can be augmented by electronic tools called "electronic contact tracing" or "exposure notification.". Some methods were built to work with smartphones; however, smartphones are not prevalent in some high-contact areas (e.g., schools and nursing homes). We present the design and initial testing of low-cost, highly privacy preserving wearable exposure notification devices. Several devices were constructed based on existing hardware and operated independently of a smartphone. The method (devices and analyses) was not able to reliably use the received signal strength indicator (RSSI) as a proxy for distance between pairs of devices; the accuracy of RSSI as a proxy for distance decreased dramatically outside of the idealized conditions. However, even an imperfect device could be useful for research on how people use and move through spaces. With some improvement, these devices could be used to understand disease spread and human or animal interaction in indoor environments.

Quantitative Susceptibility Mapping (QSM) is an MRI tool with the potential to reveal pathological changes from magnetic susceptibility measurements. Before phase data can be used to recover susceptibility (Δ χ ), the QSM process begins with two steps: data acquisition and phase estimation. We assess the performance of these steps, when applied without user intervention, on several variations of a phantom imaging task. We used a rotating-tube phantom with five tubes ranging from Δ χ =0.05 ppm to Δ χ =0.336 ppm. MRI data was acquired at nine angles of rotation for four different pulse sequences. The images were processed by 10 phase estimation algorithms including Laplacian, region-growing, branch-cut, temporal unwrapping, and maximum-likelihood methods, resulting in approximately 90 different combinations of data acquisition and phase estimation methods. We analyzed errors between measured and expected phases using the probability mass function and Cumulative Distribution Function. Repeatable acquisition and estimation methods were identified based on the probability of relative phase errors. For single-echo GRE and segmented EPI sequences, a region-growing method was most reliable with Pr (relative error <0.1) = 0.95 and 0.90, respectively. For multiecho sequences, a maximum-likelihood method was most reliable with Pr (relative error <0.1) = 0.97. The most repeatable multiecho methods outperformed the most repeatable single-echo methods. We found a wide range of repeatability and reproducibility for off-the-shelf MRI acquisition and phase estimation approaches, and this variability may prevent the techniques from being widely integrated in clinical workflows. The error was dominated in many cases by spatially discontinuous phase unwrapping errors. Any postprocessing applied on erroneous phase estimates, such as QSM's background field removal and dipole inversion, would suffer from error propagation. Our paradigm identifies methods that yield consistent and accurate phase estimates that would ultimately yield consistent and accurate Δ χ estimates., Competing Interests: The authors K. E.K, B. P.B, S. C., S. E.R., W.-T.W., J. A.B, and D. L.P. have no conflicts of interest. J. D. is the inventor of the MAGPI method and is the founder of MAGPI LLC., (Copyright © 2021 Kathryn E. Keenan et al.)

Purpose: To determine baseline accuracy and reproducibility of T 1 and T 2 relaxation times over 12 months on a dedicated radiotherapy MRI scanner., Methods: An International Society of Magnetic Resonance in Medicine/National Institute of Standards and Technology (ISMRM/NIST) System Phantom was scanned monthly on a 3T MRI scanner for 1 year. T 1 was measured using inversion recovery (T 1 -IR) and variable flip angle (T 1 -VFA) sequences and T 2 was measured using a multi-echo spin echo (T 2 -SE) sequence. For each vial in the phantom, accuracy errors (%bias) were determined by the relative differences in measured T 1 and T 2 times compared to reference values. Reproducibility was measured by the coefficient of variation (CV) of T 1 and T 2 measurements across monthly scans. Accuracy and reproducibility were mainly assessed on vials with relaxation times expected to be in physiological ranges at 3T., Results: A strong linear correlation between measured and reference relaxation times was found for all sequences tested (R 2  > 0.997). Baseline bias (and CV[%]) for T 1 -IR, T 1 -VFA and T 2 -SE sequences were +2.0% (2.1), +6.5% (4.2), and +8.5% (1.9), respectively., Conclusions: The accuracy and reproducibility of T 1 and T 2 on the scanner were considered sufficient for the sequences tested. No longitudinal trends of variation were deduced, suggesting less frequent measurements are required following the establishment of baselines., (© 2021 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)

Objectives: Opioid receipt during medical hospitalizations may be associated with subsequent long-term use. Studies, however, have not accounted for pain, which may explain chronic use. The objective of this study was to identify the association between opioid exposure during a medical hospitalization and use 6 to 12 months later., Methods: This was an observational cohort study using electronic health record data from 10 hospitals in the Cleveland Clinic Health System in 2016. Eligible patients were opioid-naïve adults with pain age 18 years and older, admitted to a medical service. Outcomes were opioid receipt during hospitalization and on discharge, and long-term opioid use, defined as ≥2 prescriptions for at least 30 pills 6 to 12 months posthospitalization. We estimated the odds of long-term opioid use by opioid exposure during the hospitalization. Models controlled for patient demographic and clinical characteristics, including patient-reported pain., Results: Among the 2971 patients in the sample, 64% received opioids during their hospitalization and 28% were discharged with opioids. Overall, 3% of patients had long-term use. Higher pain score was associated with greater odds of long-term use (adjusted odds ratio [aOR] per point increase 1.11; 95% confidence interval [CI] 1.03-1.19). No patient factors were associated with long-term use. Receipt of an opioid during a hospitalization only was not associated with long-term use (aOR 1.44, 95% CI 0.81-2.57), but receipt at discharge was (aOR 1.96, 95% CI 1.08-3.56)., Conclusions: Although opioid receipt at discharge was associated with long-term use, the number of patients this applied to was small. Pain severity was an important predictor of long-term use and should be accounted for in future studies.

Purpose: A standard MRI system phantom has been designed and fabricated to assess scanner performance, stability, comparability and assess the accuracy of quantitative relaxation time imaging. The phantom is unique in having traceability to the International System of Units, a high level of precision, and monitoring by a national metrology institute. Here, we describe the phantom design, construction, imaging protocols, and measurement of geometric distortion, resolution, slice profile, signal-to-noise ratio (SNR), proton-spin relaxation times, image uniformity and proton density., Methods: The system phantom, designed by the International Society of Magnetic Resonance in Medicine ad hoc committee on Standards for Quantitative MR, is a 200 mm spherical structure that contains a 57-element fiducial array; two relaxation time arrays; a proton density/SNR array; resolution and slice-profile insets. Standard imaging protocols are presented, which provide rapid assessment of geometric distortion, image uniformity, T 1 and T 2 mapping, image resolution, slice profile, and SNR., Results: Fiducial array analysis gives assessment of intrinsic geometric distortions, which can vary considerably between scanners and correction techniques. This analysis also measures scanner/coil image uniformity, spatial calibration accuracy, and local volume distortion. An advanced resolution analysis gives both scanner and protocol contributions. SNR analysis gives both temporal and spatial contributions., Conclusions: A standard system phantom is useful for characterization of scanner performance, monitoring a scanner over time, and to compare different scanners. This type of calibration structure is useful for quality assurance, benchmarking quantitative MRI protocols, and to transition MRI from a qualitative imaging technique to a precise metrology with documented accuracy and uncertainty., (© 2021 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

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., Competing Interests: The authors have declared that no competing interests exist.

Background: Diffusion-weighted (DW) echo-planar imaging (EPI) is prone to geometric distortions due to B 0 inhomogeneities. Both prospective and retrospective approaches have been developed to decrease and correct such distortions., Purpose: The purpose of this work was to evaluate the performance of reduced-field-of-view (FOV) acquisition and retrospective distortion correction methods in decreasing distortion artifacts for breast imaging. Coverage of the axilla in reduced-FOV DW magnetic resonance imaging (MRI) and residual distortion were also assessed., Study Type: Retrospective., Population/phantom: Breast phantom and 169 women (52.4 ± 13.4 years old) undergoing clinical breast MRI., Field Strength/sequence: A 3.0 T/ full- and reduced-FOV DW gradient-echo EPI sequence., Assessment: Performance of reversed polarity gradient (RPG) and FSL topup in correcting breast full- and reduced-FOV EPI data was evaluated using the mutual information (MI) metric between EPI and anatomical images. Two independent breast radiologists determined if coverage on both EPI data sets was adequate to evaluate axillary nodes and identified residual nipple distortion artifacts., Statistical Tests: Two-way repeated-measures analyses of variance and post hoc tests were used to identify differences between EPI modality and distortion correction method. Generalized linear mixed effects models were used to evaluate differences in axillary coverage and residual nipple distortion., Results: In a breast phantom, residual distortions were 0.16 ± 0.07 cm and 0.22 ± 0.13 cm in reduced- and full-FOV EPI with both methods, respectively. In patients, MI significantly increased after distortion correction of full-FOV (11 ± 5% and 18 ± 9%, RPG and topup) and reduced-FOV (8 ± 4% both) EPI data. Axillary nodes were observed in 99% and 69% of the cases in full- and reduced-FOV EPI images. Residual distortion was observed in 93% and 0% of the cases in full- and reduced-FOV images., Data Conclusion: Minimal distortion was achieved with RPG applied to reduced-FOV EPI data. RPG improved distortions for full-FOV images but with more modest improvements and limited correction near the nipple., Evidence Level: 3 TECHNICAL EFFICACY: Stage 1., (© 2021 International Society for Magnetic Resonance in Medicine.)

Heart rate variability (HRV) is an important biomarker for parasympathetic function and future health outcomes. The present study examined how the structure of regions in a neural network thought to maintain top-down control of parasympathetic function is associated with HRV during both rest and social stress. Participants were 127 young women (90 Black American), who completed a structural MRI scan and the Trier Social Stress Test (TSST), during which heart rate was recorded. Regression analyses were used to evaluate associations between cortical thickness in five regions of the Central Autonomic Network (CAN; anterior midcingulate cortex [aMCC], pregenual and subgenual anterior cingulate cortex [pgACC, sgACC], orbitofrontal cortex [OFC], and anterior insula) and high-frequency HRV during rest and stress. Results indicated that cortical thickness in CAN regions did not predict average HRV during rest or stress. Greater cortical thickness in the right pgACC was associated with greater peak HRV reactivity during the TSST, and survived correction for multiple comparisons, but not sensitivity analyses with outliers removed. The positive association between cortical thickness in the pgACC and peak HRV reactivity is consistent with the direction of previous findings from studies that examined tonic HRV in adolescents, but inconsistent with findings in adults, which suggests a possible neurodevelopmental shift in the relation between brain structure and autonomic function with age. Future research on age-related changes in brain structure and autonomic function would allow a more thorough understanding of how brain structure may contribute to parasympathetic function across neurodevelopment.

Imaging phantoms are used to calibrate and validate the performance of medical computed tomography (CT) systems. Many new materials developed for three-dimensional (3D) printing processes may be useful in the direct printing or casting of biomimetic and geometrically accurate CT and X-ray phantoms. The X-ray linear attenuation coefficients of polymer samples were measured to discover materials for use as tissue mimics in phantoms. This study included a cohort of polymer compounds that were tested in cured form. The cohort consisted of 101 standardized polymer samples fabricated from: two-part silicones and polyurethanes used in commercial casting processes; one-part optically cured polyurethanes used in 3D printing; and fused deposition thermoplastics used in 3D printing. The testing was performed with a commercial micro-CT imaging system from 40 kVp to 140 kVp. The X-ray linear coefficients of the samples and human tissues were plotted with error bars to allow the reader to identify suitable mimics. The X-ray linear attenuation coefficients of the tested material samples spanned a wide range of values, with a small number of them overlapping established human tissue mimic values. Twenty 3D printer materials and one castable polyurethane tracked nylon and polymethyl methacrylate (PMMA) as established X-ray mimics for fat. Five 3D printer materials tracked water as an established X-ray mimic for muscle.

Imaging phantoms are used to calibrate and validate the performance of magnetic resonance imaging (MRI) systems. Many new materials have been developed for additive manufacturing (three-dimensional [3D] printing) processes that may be useful in the direct printing or casting of dimensionally accurate, anatomically accurate, patient-specific, and/or biomimetic MRI phantoms. The T1, T2, and T2* spin relaxation times of polymer samples were tested to discover materials for use as tissue mimics and structures in MRI phantoms. This study included a cohort of polymer compounds that was tested in cured form. The cohort consisted of 101 standardized polymer samples fabricated from: two-part silicones and polyurethanes used in commercial casting processes; one-part optically cured polyurethanes used in 3D printing; and fused deposition thermoplastics used in 3D printing. The testing was performed at 3 T using inversion recovery, spin echo, and gradient echo sequences for T1, T2, and T2*, respectively. T1, T2, and T2* values were plotted with error bars to allow the reader to assess how well a polymer matches a tissue for a specific application. A correlation was performed between T1, T2, T2* values and material density, elongation, tensile strength, and hardness. Two silicones, SI&#95;XP-643 and SI&#95;P-45, may be usable mimics for reported liver values; one silicone, SI&#95;XP-643, may be a useful mimic for muscle; one silicone, SI&#95;XP-738, may be a useful mimic for white matter; and four silicones, SI&#95;P-15, SI&#95;GI-1000, SI&#95;GI-1040, and SI&#95;GI-1110, may be usable mimics for spinal cord. Elongation correlated to T2 (p = 0.0007), tensile strength correlated to T1 (p = 0.002), T2 (p = 0.0003), and T2* (p = 0.003). The 80 samples not providing measurable signal with T1, T2, T2* relaxation values too short to measure with the standard sequences, may be useful for MRI-invisible fixturing and medical devices at 3 T.

Purpose: MRI parameters, such as T 1 , T 2 , and ADC, of tissue-mimicking materials in MRI phantoms can exhibit temperature dependence, and bore temperatures can vary over a 10°C range across different MRI systems. If this variation is not accurately corrected for, the quantitative nature of reference or phantom measurements is irrelevant. Available thermometers require opening the phantoms to probe the temperature, which can introduce contaminants that may affect the stability and accuracy of the phantom. An integrated, MRI-visible thermometer that can be read using typical imaging protocols is needed., Theory and Methods: An MRI-compatible thermometer was designed using liquid crystals (LCs) that exhibit rapid transitions between the LC cholesteric state and isotropic state in the room temperature range spanning 17°C to 23°C in 1.0°C increments. The LC thermometer was assessed visually and using superconducting quantum interference device magnetometry, NMR, and MRI techniques., Results: The signal generated from the LC thermometer was visible with spin-echo and gradient-echo MRI images. The LC state transition temperatures were visually referenced to a National Institute of Standards and Technology-traceable thermometer, and these LC state transitions were confirmed using superconducting quantum interference device magnetometry and NMR., Conclusions: The LC MR-visible thermometer had measurable changes in relative signal with temperature, which were invariant to a variety of imaging sequences used., (© 2020 International Society for Magnetic Resonance in Medicine.)

Background: The T 1 Mapping and Extracellular volume (ECV) Standardization (T1MES) program explored T 1 mapping quality assurance using a purpose-developed phantom with Food and Drug Administration (FDA) and Conformité Européenne (CE) regulatory clearance. We report T 1 measurement repeatability across centers describing sequence, magnet, and vendor performance., Methods: Phantoms batch-manufactured in August 2015 underwent 2 years of structural imaging, B 0 and B 1 , and "reference" slow T 1 testing. Temperature dependency was evaluated by the United States National Institute of Standards and Technology and by the German Physikalisch-Technische Bundesanstalt. Center-specific T 1 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 T 1 mapping sequences. Image and temperature data were analyzed semi-automatically. Repeatability of serial T 1 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 T 1 variation., Results: Over 2 years, phantom gel integrity remained intact (no rips/tears), B 0 and B 1 homogenous, and "reference" T 1 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, T 1 (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 T 1 times with "reference" T 1 was similar across Siemens and Philips CMR systems at both field strengths (adjusted R 2 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 < 1 and 2% respectively. Repeatability was narrower for 1.5 T over 3 T. Within T1MES repeatability for native T 1 was narrow for several sequences, for example, at 1.5 T, Siemens MOLLI 5s(3s)3s prototype number 448B (mean CoV = 0.27%) and Philips modified Look-Locker inversion recovery (MOLLI) 3s(3s)5s (CoV 0.54%), and at 3 T, Philips MOLLI 3b(3s)5b (CoV 0.33%) and Siemens shortened MOLLI (ShMOLLI) prototype 780C (CoV 0.69%). After adjusting for temperature and field strength, it was found that the T 1 mapping sequence and scanner software version (both P < 0.001 at 1.5 T and 3 T), and to a lesser extent the scanner model (P = 0.011, 1.5 T only), had the greatest influence on T 1 across multiple centers., Conclusion: The T1MES CE/FDA approved phantom is a robust quality assurance device. In a multi-center setting, T 1 mapping had performance differences between field strengths, sequences, scanner software versions, and manufacturers. However, several specific combinations of field strength, sequence, and scanner are highly repeatable, and thus, have potential to provide standardized assessment of T 1 times for clinical use, although temperature correction is required for native T 1 tubes at least.

Magnetic resonance fingerprinting (MRF) is a general framework to quantify multiple MR-sensitive tissue properties with a single acquisition. There have been numerous advances in MRF in the years since its inception. In this work we highlight some of the recent technical developments in MRF, focusing on sequence optimization, modifications for reconstruction and pattern matching, new methods for partial volume analysis, and applications of machine and deep learning. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:993-1007., (© 2019 International Society for Magnetic Resonance in Medicine.)

Magnetic resonance fingerprinting (MRF) is a powerful quantitative MRI technique capable of acquiring multiple property maps simultaneously in a short timeframe. The MRF framework has been adapted to a wide variety of clinical applications, but faces challenges in technical development, and to date has only demonstrated repeatability and reproducibility in small studies. In this review, we discuss the current implementations of MRF and their use in a clinical setting. Based on this analysis, we highlight areas of need that must be addressed before MRF can be fully adopted into the clinic and make recommendations to the MRF community on standardization and validation strategies of MRF techniques. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:675-692., (© 2019 International Society for Magnetic Resonance in Medicine.)

Background: Scanner upgrades due to software and hardware changes are an inevitable part of MR research and, without quality assurance protocols, can jeopardize studies., Purpose: To evaluate changes in T 1 relaxation time by inversion recovery (IR) and variable flip angle (VFA) measurements on a 3T system that underwent an "everything but the magnet" upgrade., Study Type: Longitudinal., Phantom: An International Society of Magnetic Resonance in Medicine / National Institute of Standards and Technology (ISMRM/NIST) system phantom with repeated measurements across multiple (n = 3) days., Field Strength/sequence: T 1 IR, VFA at 3T., Assessment: The T 1 measurements by IR and VFA were compared with the nuclear magnetic resonance (NMR) measurements, which constitute the known values for the ISMRM/NIST system phantom, to determine the measurement error., Statistical Tests: Descriptive., Results: The T 1 VFA measurement errors were distributed around zero (-15% to +10%) on the original system and then the errors were distributed entirely above zero post-upgrade (+5% to 30%). The T 1 IR results had a dramatic increase in error distribution (±5% original, ±20% post-upgrade) prior to the identification of signal saturation as an issue. Once the signal saturation was accounted for, the T 1 IR errors decreased to ±10% post-upgrade., Data Conclusion: The T 1 VFA measurement differences between the original and post-upgrade systems can be entirely attributed to contributions from B 1 . The T 1 IR measurements demonstrate the need for quantitative quality assurance (QA) processes. The site under study passed the QA protocols in place, which did not identify the increased T 1 error, nor the signal saturation issue. To improve on this study, we would make systematic, quantitative measurements at intervals less than a year and following any hardware or software upgrade., Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2019;50:1948-1954., (Published 2019. This article is a U.S. Government work and is in the public domain in the USA.)

Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019., (© 2019 International Society for Magnetic Resonance in Medicine.)

Objective: Eating pathology is more prevalent among women compared to men, but prevalence and correlates associated with eating pathology likely vary among subgroups of women. This study examines prevalence and correlates of restrictive and weight control-related eating pathology in sexual minority women., Method: Data were collected from the Pittsburgh Girls Study (PGS). Participants reported on sexual orientation, and race, and body mass index (BMI) was derived from interviewer collected height and weight. Participants completed the Body Image Measure and the Eating Attitudes Test-26., Results: Sexual minority women reported higher BMIs [F (1, 862) = 14.69, p < .001], higher levels of body dissatisfaction [F (1, 960) = 3.12, p < .01], and higher levels of eating pathology [F (1, 950) = 14.21, p < .001] than heterosexual women. Body dissatisfaction mediated the relationship between BMI and eating pathology, and levels of associations were not attenuated by sexual minority status. Race moderated the association between sexual orientation and eating pathology; compared to all other groups, White sexual minority women had the highest level of eating pathology. Discussion Results indicate that White sexual minority women have higher levels of eating pathology than Black sexual minority women and both Black and White heterosexual women. Future studies that draw from larger and more diverse, community-based samples are needed., (© 2019 Wiley Periodicals, Inc.)

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely investigated and utilized as magnetic resonance imaging (MRI) contrast and therapy agents due to their large magnetic moments. Local field inhomogeneities caused by these high magnetic moments are used to generate T 2 contrast in clinical high-field MRI, resulting in signal loss (darker contrast). Here we present strong T 1 contrast enhancement (brighter contrast) from SPIONs (diameters from 11 nm to 22 nm) as observed in the ultra-low field (ULF) MRI at 0.13 mT. We have achieved a high longitudinal relaxivity for 18 nm SPION solutions, r 1  = 615 s -1 mM -1 , which is two orders of magnitude larger than typical commercial Gd-based T 1 contrast agents operating at high fields (1.5 T and 3 T). The significantly enhanced r 1 value at ultra-low fields is attributed to the coupling of proton spins with SPION magnetic fluctuations (Brownian and Néel) associated with a low frequency peak in the imaginary part of AC susceptibility (χ"). SPION-based T 1 -weighted ULF MRI has the advantages of enhanced signal, shorter imaging times, and iron-oxide-based nontoxic biocompatible agents. This approach shows promise to become a functional imaging technique, similar to PET, where low spatial resolution is compensated for by important functional information.

Purpose: To examine the longitudinal cohesion and stability of sexual minority status indicators., Methods: The sample comprised 2,450 girls recruited from the city of Pittsburgh at ages 5-8 years. Sexual attraction, sexual partnering, romantic partnering, and sexual orientation identity were assessed between 14 and 22 years., Results: Repeated measures latent class analysis identified three sexual minority trajectories: primarily other-sex oriented (n = 716), primarily same-sex oriented (n = 90), and bisexually oriented (n = 235). Sexual minority status indicators displayed fluidity over time but cohered within latent classes., Conclusions: Within this large sample of girls, several distinct sexuality trajectories emerged. Trajectories are relatively stable from adolescence to young adulthood., (Copyright © 2018 The Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T 1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3 T., Methods: A T 1 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 T 1 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 T 1 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 T 1 quantification (errors < 15%). Further optimization in terms of flip-angle choice for each tissue application, and the use of B 1 correction, are needed to improve the robustness of VFA protocols for T 1 mapping. Magn Reson Med 79:2564-2575, 2018. © 2017 International Society for Magnetic Resonance in Medicine., (© 2017 International Society for Magnetic Resonance in Medicine.)