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Purpose: Ktrans$$ {K}^{\mathrm{trans}} $$ has often been proposed as a quantitative imaging biomarker for diagnosis, prognosis, and treatment response assessment for various tumors. None of the many software tools for Ktrans$$ {K}^{\mathrm{trans}} $$ quantification are standardized. The ISMRM Open Science Initiative for Perfusion Imaging–Dynamic Contrast‐Enhanced (OSIPI‐DCE) challenge was designed to benchmark methods to better help the efforts to standardize Ktrans$$ {K}^{\mathrm{trans}} $$ measurement. Methods: A framework was created to evaluate Ktrans$$ {K}^{\mathrm{trans}} $$ values produced by DCE‐MRI analysis pipelines to enable benchmarking. The perfusion MRI community was invited to apply their pipelines for Ktrans$$ {K}^{\mathrm{trans}} $$ quantification in glioblastoma from clinical and synthetic patients. Submissions were required to include the entrants' Ktrans$$ {K}^{\mathrm{trans}} $$ values, the applied software, and a standard operating procedure. These were evaluated using the proposed OSIPIgold$$ \mathrm{OSIP}{\mathrm{I}}_{\mathrm{gold}} $$ score defined with accuracy, repeatability, and reproducibility components. Results: Across the 10 received submissions, the OSIPIgold$$ \mathrm{OSIP}{\mathrm{I}}_{\mathrm{gold}} $$ score ranged from 28% to 78% with a 59% median. The accuracy, repeatability, and reproducibility scores ranged from 0.54 to 0.92, 0.64 to 0.86, and 0.65 to 1.00, respectively (0–1 = lowest–highest). Manual arterial input function selection markedly affected the reproducibility and showed greater variability in Ktrans$$ {K}^{\mathrm{trans}} $$ analysis than automated methods. Furthermore, provision of a detailed standard operating procedure was critical for higher reproducibility. Conclusions: This study reports results from the OSIPI‐DCE challenge and highlights the high inter‐software variability within Ktrans$$ {K}^{\mathrm{trans}} $$ estimation, providing a framework for ongoing benchmarking against the scores presented. Through this challenge, the participating teams were ranked based on the performance of their software tools in the particular setting of this challenge. In a real‐world clinical setting, many of these tools may perform differently with different benchmarking methodology. [ABSTRACT FROM AUTHOR]

This manuscript describes the ISMRM OSIPI (Open Science Initiative for Perfusion Imaging) lexicon for dynamic contrast‐enhanced and dynamic susceptibility‐contrast MRI. The lexicon was developed by Taskforce 4.2 of OSIPI to provide standardized definitions of commonly used quantities, models, and analysis processes with the aim of reducing reporting variability. The taskforce was established in February 2020 and consists of medical physicists, engineers, clinicians, data and computer scientists, and DICOM (Digital Imaging and Communications in Medicine) standard experts. Members of the taskforce collaborated via a slack channel and quarterly virtual meetings. Members participated by defining lexicon items and reporting formats that were reviewed by at least two other members of the taskforce. Version 1.0.0 of the lexicon was subject to open review from the wider perfusion imaging community between January and March 2022, and endorsed by the Perfusion Study Group of the ISMRM in the summer of 2022. The initial scope of the lexicon was set by the taskforce and defined such that it contained a basic set of quantities, processes, and models to enable users to report an end‐to‐end analysis pipeline including kinetic model fitting. We also provide guidance on how to easily incorporate lexicon items and definitions into free‐text descriptions (e.g., in manuscripts and other documentation) and introduce an XML‐based pipeline encoding format to encode analyses using lexicon definitions in standardized and extensible machine‐readable code. The lexicon is designed to be open‐source and extendable, enabling ongoing expansion of its content. We hope that widespread adoption of lexicon terminology and reporting formats described herein will increase reproducibility within the field. [ABSTRACT FROM AUTHOR]

Purpose: Cardiac-induced liver motion can bias liver ADC measurements and compromise reproducibility. The purpose of this work was to enable motion-robust DWI on multiple MR scanners and assess reproducibility of the resulting liver ADC measurements., Methods: First moment-optimized diffusion imaging (MODI) was implemented on three MR scanners with various gradient performances and field strengths. MODI-DWI and conventional Stejskal-Tanner monopolar (MONO) DWI were acquired in eight (N = 8) healthy volunteers on each scanner, and DWI repetitions were combined using three different averaging methods. For each combination of scanner, acquisition, and averaging method, ADC measurements from each liver segment were collected. Systematic differences in ADC values between scanners and methods were assessed with linear mixed effects modeling, and reproducibility was quantified via reproducibility coefficients., Results: MODI reduced left-right liver lobe ADC bias from 0.43 × 10 -3  mm 2 /s (MONO) to 0.19 × 10 -3  mm 2 /s (MODI) when simple (unweighted) repetition averaging was used. The bias was reduced from 0.23 × 10 -3  mm 2 /s to 0.06 × 10 -3  mm 2 /s using weighted averaging, and 0.14 × 10 -3  mm 2 /s to 0.01 × 10 -3  mm 2 /s using squared weighted averaging. There was no significant difference in ADC measurements between field strengths or scanner gradient performance. MODI improved reproducibility coefficients compared to MONO: 0.84 × 10 -3  mm 2 /s vs. 0.63 × 10 -3  mm 2 /s (MODI vs. MONO) for simple averaging, 0.66 × 10 -3  mm 2 /s vs. 0.50 × 10 -3  mm 2 /s for weighted averaging, and 0.61 × 10 -3  mm 2 /s vs. 0.47 × 10 -3  mm 2 /s for squared weighted averaging., Conclusion: The feasibility of motion-robust liver DWI using MODI was demonstrated on multiple MR scanners. MODI improved interlobar agreement and reproducibility of ADC measurements in a healthy cohort., (© 2024 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Objectives: Ferumoxytol is a superparamagnetic iron-oxide product that is increasingly used off-label for contrast-enhanced magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). With the recent regulatory approval of generic ferumoxytol, there may be an opportunity to reduce cost, so long as generic ferumoxytol has similar imaging performance to brand name ferumoxytol. This study aims to compare the relaxation-concentration dependence and MRI performance of brand name ferumoxytol with generic ferumoxytol through phantom and in vivo experiments. The secondary purpose was to determine the optimal flip angle and optimal weight-based dosing., Materials and Methods: Phantom experiments were performed using both brand name (AMAG Pharmaceuticals) and generic (Sandoz Pharmaceuticals) ferumoxytol products. Each ferumoxytol product was diluted in saline, and separately in adult bovine whole blood, at 5 iron concentrations ranging from 0.3 to 2.1 mM. Vials were placed in an MR-compatible water bath at 37°C and imaged at both 1.5 T and 3.0 T. Longitudinal and transverse relaxation rate constants (R1, R2, R2*) were measured for each ferumoxytol concentration, and relaxation-concentration curves were estimated. An in vivo dose accumulation study with flip angle optimization was also implemented using a cross-over design, in healthy volunteers. Cumulative doses of 1, 3, 5, and 7 mg/kg diluted ferumoxytol were administered prior to MRA of the chest on a 3.0 T clinical MRI system. For each incremental dose, the flip angle was varied from 40° to 10° in -10° increments over 5 breath-holds followed by a repeated 40° flip angle acquisition. Regions of interest were drawn in the aortic arch, paraspinous muscles, and a noisy area outside of the patient, free from obvious artifact. Signal-to-noise ratio (SNR) was calculated as the quotient of the average signal in the aortic arch and the standard deviation of the noise, corrected for a Rician noise distribution. Contrast-to-noise ratio was calculated as the difference in SNR between the aorta and paraspinous muscles. Absolute SNR and contrast-to-noise ratio values were compared between products for different flip angles and doses., Results: There were no statistically significant or clinically relevant differences in relaxation-concentration curves between AMAG and Sandoz products in phantom experiments. Six healthy volunteers (38.8 ± 11.5 years, 3 female, 3 male) were successfully recruited and completed both imaging visits. No clinically relevant differences in image quality were observed between ferumoxytol products. The optimal flip angle range and dose for both products was 20°-30° and 5 mg/kg, respectively., Conclusions: Brand name and generic ferumoxytol products can be used interchangeably for MRA., Competing Interests: Conflicts of interest and sources of funding: No author has any relevant conflicts. Unrelated to this work, Dr Reeder has ownership interests in Calimetrix, Reveal Pharmaceuticals, Cellectar Biosciences, Elucent Medical, Vista.AI, and RevOps. Dr Reeder provides consulting services to Bracco Diagnostics, ProTara, Bayer Healthcare, and Marea Therapeutics. Further, the University of Wisconsin receives research support from GE Healthcare, Bracco Diagnostics, Bayer Healthcare, and Pfizer. This project was supported by the Departments of Radiology and Medical Physics, University of Wisconsin., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: To determine the efficacy of genicular artery embolisation (GAE) compared with sham GAE for pain reduction in patients with symptomatic mild-to-moderate knee osteoarthritis (KOA)., Design: Double-blind randomised sham-controlled clinical trial conducted from June 2019 to December 2021. The follow-up period was 4 months., Setting: Single-centre study conducted at a university medical centre in Rotterdam, Netherlands., Participants: 58 adults with symptomatic mild-to-moderate KOA not improving with conservative treatment., Interventions: Participants were randomised to receive either GAE treatment or a sham GAE treatment., Main Outcome Measures: The primary outcome was reduction of pain measured with the Knee Injury and Osteoarthritis Outcome Score pain subscale (0-100, with 0 representing the worst pain outcome and 100 the best) after 4 months. Outcomes were assessed at baseline and 1 and 4 months., Results: From June 2019 to December 2021, 58 patients were included. 29 patients were randomised to the GAE group and 29 to the sham group. All participants completed the study. The mean pain reduction after 4 months was 21.4 (95% CI 13.9 to 28.8) for the GAE group and 18.4 points (95% CI 11.6 to 25.1) for the sham group. The between-group difference for the mean pain reduction was 3.0 (95% CI -7.1 to 13.0) with an estimated Cohen's d effect size of d = 0.15 (95% CI -0.37 to 0.66). Group allocation was not a significant contributor to pain reduction (p = 0.31). No serious adverse events (AEs) occurred. 23 mild AEs occurred in the GAE group and 5 in the sham group., Conclusion: We did not establish a clinical effect of GAE in patients with mild-to-moderate KOA as GAE produced a similar effect on pain reduction as a sham GAE procedure., Trial Registration Number: NCT03884049., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)