Magnetic Resonance in Medicine最新文献

{"title":"Self-Derived Dynamic Field Map Estimation and Correction in CEST MRI.","authors":"Sultan Z Mahmud, Kevin Ju, Jianping Xu, Linda Knutsson, Peter van Zijl, Hye-Young Heo","doi":"10.1002/mrm.70445","DOIUrl":"10.1002/mrm.70445","url":null,"abstract":"<p><strong>Purpose: </strong>To demonstrate a self-derived, dynamic field map (∆B₀) estimation and correction method for improved CEST measurements without additional scans, especially in the presence of subject motion.</p><p><strong>Methods: </strong>Dynamic ∆B₀ maps were derived directly from the CEST images acquired with rosette readout trajectories by segmenting the rosette k-space data. The rosette ∆B₀ mapping accuracy was validated against standard dual-echo Cartesian GRE ∆B₀ maps. The utility of dynamic ∆B₀ estimation and correction for CEST MRI was demonstrated in healthy volunteers at 3 T with and without the presence of motion.</p><p><strong>Results: </strong>Self-derived dynamic ∆B₀ correction substantially improved the CEST measurements compared to static ∆B₀ correction, particularly under conditions of motion. The mean differences between the motion-free and motion-corrupted global Z-spectra were 0.23% ± 0.06% (p > 0.2) and 3.10% ± 0.70% (p < 0.03) with dynamic and static ΔB₀ correction, respectively. Dynamic ΔB₀-corrected APTw values in the presence of motion also showed very high correlation (R ≥ 0.96) with motion-free values, whereas static ΔB₀-corrected APTw values showed very poor correlation (R ≤ 0.02).</p><p><strong>Conclusion: </strong>By enabling dynamic ΔB₀ mapping, rosette-CEST MRI enhances the accuracy of CEST measurements in the presence of subject motion-induced B₀ fluctuations, eliminating the need for additional scans or separate alignment of ΔB₀ and saturation spectra.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1778-1788"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13419123/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147982064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative Susceptibility Mapping of Kidney Stones: An Ex Vivo MRI Phantom Study.","authors":"Lion H Mücke, Frederik B Laun, Ruben de Figueiredo Cardoso, Guillaume Flé, Jennifer Lorenz, Alexander Fichte, Michael Uder, Nadine Bayerl, Jannis Hanspach","doi":"10.1002/mrm.70460","DOIUrl":"10.1002/mrm.70460","url":null,"abstract":"<p><strong>Purpose: </strong>To visualize and characterize the five most common kidney stone types based on their magnetic susceptibilities in MRI using QSM.</p><p><strong>Methods: </strong>Three water-based agar phantoms were constructed, containing a total of 53 ex vivo kidney stones of varying types and sizes. Seven different MRI multi-echo gradient echo sequences were employed at field strengths of 1.5 T and 3 T. Each acquisition was repeated three times. Susceptibility maps were reconstructed and mean susceptibility values calculated for the individual kidney stones (normalized to the agar gel). Five of the most common kidney stone types-carbonate apatite, calcium oxalate, uric acid, cystine, and struvite-were investigated with respect to different sequence parameters and field strengths.</p><p><strong>Results: </strong>All examined kidney stones were reliably visualized as diamagnetic using QSM. Overall, good repeatability was observed for the mean susceptibility values and standard deviations of the individual kidney stones. Mean susceptibility values were highly consistent across acquisitions at both field strengths for kidney stones belonging to the five major types with diameters larger than 3.0 mm (66% of all stones). The overall mean susceptibility values (± SD) were - 1.25 ± 0.16 ppm for carbonate apatite, -1.08 ± 0.13 ppm for calcium oxalate, -0.94 ± 0.17 ppm for uric acid, -1.32 ± 0.16 ppm for cystine, and -1.28 ± 0.28 ppm for struvite.</p><p><strong>Conclusion: </strong>Our data indicate that QSM is well-suited to reliably visualize kidney stones and distinguish certain types among the five most common kidney stone compositions using MRI. This represents a crucial step toward in vivo imaging of suspected urolithiasis in clinical practice.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1846-1859"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13419359/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148176398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Static Phantom for Harmonization of Hyperpolarized [1-¹³C]Pyruvate Metabolic Magnetic Resonance Imaging.","authors":"Kristina P Jacobsen, Ingeborg S Skre, Rie B Olin, Mathilde H Lerche","doi":"10.1002/mrm.70442","DOIUrl":"10.1002/mrm.70442","url":null,"abstract":"<p><strong>Purpose: </strong>To develop and characterize a static, reusable ¹³C phantom designed to assess and support the harmonization of MRI setups used for hyperpolarized (HP) [1-¹³C]pyruvate imaging.</p><p><strong>Methods: </strong>The phantom was designed as a 200-mm-diameter polycarbonate sphere filled with 8M natural abundance urea and incorporating distinct modules for assessing field and SNR homogeneity, geometric fidelity, spatial resolution, and metabolite quantification. The structural design, materials and chemical composition were selected to match the current technical requirements and capabilities in HP [1-¹³C]pyruvate MRI. The phantom was characterized on a 3T clinical MR scanner to demonstrate representative use cases.</p><p><strong>Results: </strong>The phantom enabled assessment of field homogeneity ( <math> <mrow><msub><mi>B</mi> <mn>0</mn></msub> </mrow> </math> variation was approximately 20 Hz and <math> <mrow><msubsup><mi>B</mi> <mn>1</mn> <mo>+</mo></msubsup> </mrow> </math> relative flip angle was 1.0 <math><mrow><mo>±</mo></mrow> </math> 0.1) and Signal-to-Noise Ratio of the MRI setup. Spectral-spatial (SPSP) spiral imaging of the geometric module and resolution module demonstrated how post-processing pipelines can influence spatial fidelity and effective resolution. The quantification module, containing compounds with chemical shifts matching those of pyruvate and its principal metabolites and mixed in physiologically relevant ratios, enabled metabolite ratio quantification using both CSI and SPSP spiral imaging.</p><p><strong>Conclusion: </strong>Initial characterization demonstrates that the proposed ¹³C phantom is a practical and versatile tool for benchmarking HP ¹³C MRI system performance, thereby supporting harmonization in multicenter clinical HP ¹³C MRI studies.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1769-1777"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13419006/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148016369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collaborative Reconstruction of PROPELLER-EPI Data Using POCSMUSE (CORPUSE) for High-Fidelity Diffusion MRI.","authors":"Hailin Xiong, Liyuan Liang, Shihui Chen, Yi Li, Chenglang Yuan, Tianbaige Liu, Xiaorui Xu, Hing-Chiu Chang","doi":"10.1002/mrm.70448","DOIUrl":"10.1002/mrm.70448","url":null,"abstract":"<p><strong>Purpose: </strong>To develop a reconstruction framework for DW-PROPELLER-EPI that improves image quality and SNR efficiency under per-blade acceleration while minimizing EPI-related artifacts, enabling high-resolution diffusion-tensor imaging (DTI) with fewer blades.</p><p><strong>Methods: </strong>We propose CORPUSE, a joint reconstruction framework adapted from POCSMUSE and tailored for multiblade DW-PROPELLER-EPI. The method integrates distortion-correction operators into a joint-blade reconstruction model and exploits the inherent redundancy of multiblade sampling. Leveraging self-extracted composite 2D phase errors and blade-specific field maps as physics-based constraints, CORPUSE improves reconstruction performance. By using wider blades with higher per-blade acceleration, the framework increases scan efficiency while preserving image quality and geometric fidelity. The framework was evaluated in healthy volunteers on a 1.5T MRI scanner across varying numbers of blades and with two PROPELLER-EPI trajectories: long-axis (LAP) and short-axis (SAP), under different per-blade accelerations and scan conditions.</p><p><strong>Results: </strong>In vivo experiments showed that CORPUSE improved image sharpness, geometric fidelity, and overall reconstruction quality compared with conventional PROPELLER-EPI reconstruction. These improvements enabled higher per-blade acceleration and wider blades without compromising image quality, thereby supporting more flexible and efficient reconstruction for LAP and SAP trajectory. Additionally, CORPUSE demonstrated greater motion resilience than multishot EPI based on multiplexed sensitivity encoding (MUSE), preserving structural detail even under subtle motion conditions.</p><p><strong>Conclusion: </strong>The CORPUSE framework enables high-resolution, high-quality DTI with fewer blades, improving the practicality of DW-PROPELLER-EPI. By maintaining SNR and geometric accuracy under high per-blade acceleration, it offers a robust and efficient alternative to other multishot diffusion imaging approaches.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1929-1946"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421002/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148055587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"T1-weighting in Steady-State FLASH MRI-Diffusion Is Not Only Supportive but Mandatory for the Contrast.","authors":"Simon Weinmüller, Deepak Charles Chellapandian, Jonathan Endres, Jochen Leupold, Florian Gritsch, Fabian Wagner, Rainer Schneider, Moritz Zaiss","doi":"10.1002/mrm.70443","DOIUrl":"10.1002/mrm.70443","url":null,"abstract":"<p><strong>Purpose: </strong>FLASH imaging is widely assumed to produce a T₁-weighted steady-state contrast using RF- and gradient-spoiling. We observed substantial overestimation of CSF signals in simulations, when diffusion was neglected and realistic proton density was applied. This work investigates the role of diffusion in steady-state FLASH contrast formation and its implications for simulation-based modeling and measurement.</p><p><strong>Methods: </strong>FLASH sequences were simulated using phase graph simulations using a synthetic brain phantom with and without diffusion and realistic PD values to show the contrast change. The impact of neglecting diffusion in synthetic training data was evaluated using a segmentation network trained on simulated data and tested on in vivo measurement. Experimental validation of the contrast change was performed using a 3D-printed brain phantom using silicone oil as a low-diffusivity compartment.</p><p><strong>Results: </strong>Without diffusion, simulations showed CSF signal intensities higher than WM, resulting in a contrast change. Diffusion suppresses higher-order echoes in long T₂ tissues and is essential for achieving the T₁-weighted steady-state contrast. A NN trained without diffusion fails to generalize to in vivo data and measurements with silicone oil compartments confirm the contrast changes in low-diffusivity media.</p><p><strong>Conclusion: </strong>Diffusion is essential for realistic FLASH simulations of long T₂ tissues such as CSF. Steady-state FLASH contrast arises from the interplay of RF-, gradient-spoiling, and \"multi-TR-relaxation-spoiling\" governed by T₂-decay and diffusion effects. For many quadratic phase cycling schemes, diffusion is required to obtain realistic T₁-weighted contrast in MR simulations and should not be neglected in simulations or simulation-based deep learning applications.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1789-1797"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421012/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148295271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Sub-Microsecond Switch Enabling SWIFT ²³Na Imaging at 10.5 T.","authors":"Russell L Lagore, Simon Schmidt, Edward J Auerbach, Naoharu Kobayashi, Christoph Schildknecht, Steen Moeller, Elnaz Mahmoudi Mahmoudalilou, Štefan Zbýň, Jutta Ellermann, Gregor Adriany, Gregory J Metzger","doi":"10.1002/mrm.70461","DOIUrl":"10.1002/mrm.70461","url":null,"abstract":"<p><strong>Purpose: </strong>To enable sodium SWIFT imaging, which is a zero-echo time imaging technique, at ultra-high magnetic fields through the development of custom electronics hardware, and to showcase this capability with in vivo imaging results.</p><p><strong>Methods: </strong>The custom hardware developed consists of a high-speed optical trigger with 10 ns resolution, an in-bore PIN diode driver capable of sourcing high current, and RF switches (both an in-line switchable attenuator and transmit/receive switch) optimized to achieve sub-microsecond switching speeds while also producing isolation between the transmitter and receiver.</p><p><strong>Results: </strong>Practical switching speeds of 0.6 μs (receive to transmit) and 1.7 μs (transmit to receive) are achieved on the RF switches, limited by transient-induced spurious emissions from the low noise amplifier. Transmit to receive isolation of 115 dB is achieved over a 1 MHz bandwidth, with 120 dB of isolation at the Larmor frequency. This was crucial to suppress unblanked RFPA noise. SWIFT images of the human wrist with 1.5 mm isotropic resolution were acquired in less than 5 min to demonstrate the utility of sodium SWIFT imaging at ultra-high field. SWIFT imaging signal-to-noise ratio in a reference phantom with heterogeneous sodium concentrations was comparable to ultra-short echo time imaging, which provided assurance that hardware had achieved the necessary specifications.</p><p><strong>Conclusions: </strong>The feasibility of sodium SWIFT imaging at ultra-high field was established, and a musculoskeletal imaging application was demonstrated. The success of this work enables further development of SWIFT at high and ultra-high fields for imaging of sodium, proton, and other nuclei.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1991-2003"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13419349/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148205360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Denoising of ASL Data Using Deep Learning Priors Generated From Distribution Remapping.","authors":"Ziyang Xu, Rong Guo, Ziwen Ke, Yudu Li, Yibo Zhao, Wen Jin, Ruihao Liu, Ziyu Meng, Yao Li, Zhi-Pei Liang","doi":"10.1002/mrm.70471","DOIUrl":"10.1002/mrm.70471","url":null,"abstract":"<p><strong>Purpose: </strong>To develop an effective deep learning (DL)-based method to denoise arterial spin labeling (ASL) data.</p><p><strong>Methods: </strong>Conventional DL-based ASL denoising methods often suffer from overfitting and poor generalization when training data are limited. The proposed method overcame this problem using two strategies: (i) perform data augmentation to create large training data and (ii) denoise in-distribution and out-of-distribution components of the target perfusion-weighted image separately. Specifically, Image-to-Image Schrödinger Bridge (I²SB)-based distribution remapping transforms were applied to the large public ASL datasets so that their intensity distribution matched that of the data to be denoised. U-Net-based DL denoisers were trained on the remapped data to capture in-distribution features. High-SNR outputs from the DL-denoiser were incorporated into a Bayesian model to reconstruct the out-of-distribution features with sparsity constraints, generating denoised images for cerebral blood flow (CBF) quantification.</p><p><strong>Results: </strong>Simulation studies highlighted the importance of distribution remapping for effective data augmentation in limited-data scenarios. Both simulation and in vivo experiments showed that the proposed method outperformed state-of-the-art approaches, achieving an average SNR improvement of approximately 7 dB. Evaluations on multiple datasets confirmed robust and generalizable performance across different ASL sequences and imaging protocols. To demonstrate clinical potential, our method was applied to denoising stroke patient data (using only one-sixth of total averages with ˜83% reduction in scan time) and produced comparable CBF maps to the conventional ASL method.</p><p><strong>Conclusion: </strong>The proposed method enables effective ASL denoising with limited training data. It has the potential to accelerate ASL acquisition, enhance image quality, and improve clinical utility.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1972-1982"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421004/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148218038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Respiratory Motion Management in Abdominal MRI: Revisiting the Gap Between Technical Advances and Clinical Translation.","authors":"Li Feng, Hersh Chandarana","doi":"10.1002/mrm.70475","DOIUrl":"10.1002/mrm.70475","url":null,"abstract":"<p><p>The inherently slow acquisition speed of MRI makes abdominal imaging highly sensitive to respiratory motion artifacts. Since the early days of MRI, the development of respiratory motion compensation techniques has been an active research topic, and this field has seen substantial progress. Despite these advances, the majority of these techniques are not used in daily clinical practice, and motion management methods used in clinical abdominal MRI today have changed little over the past decades. This observation points to a significant gap between technical innovation and clinical translation in this area. This review is motivated by this question: why have so many motion management techniques not been adopted into routine clinical workflows? Unlike conventional survey-style reviews that focus on summarizing emerging methods, this article takes a different, and perhaps opposite, perspective to investigate why those technologically sophisticated innovations are misaligned with practical clinical needs. Specifically, we discuss the barriers behind the gap between research advances and clinical practice, clarify the clinical requirements for effective respiratory motion management in abdominal MRI, and highlight research directions with stronger relevance to routine workflows. The review begins with an overview of the clinical impact of respiratory motion in abdominal MRI, followed by a discussion of standard abdominal MRI sequences and their motion sensitivity. We then summarize current clinical strategies and advanced approaches, along with the barriers that hinder their clinical adoption. The article concludes with future directions and broader lessons learned from this translational gap, with the goal of guiding future developments toward improved clinical integration.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1814-1833"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13359306/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148252100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-Time Monitoring of Tissue Oxygenation During Hyperbaric Oxygen Exposure Using In Vivo EPR Oximetry.","authors":"Maciej M Kmiec, Sergey V Petryakov, Alireza Kheirollah, Conner S Ubert, Ryan C O'Connell, Periannan Kuppusamy","doi":"10.1002/mrm.70444","DOIUrl":"10.1002/mrm.70444","url":null,"abstract":"<p><strong>Purpose: </strong>Hyperbaric oxygen (HBO) therapy increases blood oxygen levels by exposing patients to 100% oxygen under elevated pressure and is used clinically for conditions such as decompression sickness, carbon monoxide poisoning, chronic wounds, and impaired tissue healing. However, real-time precise and quantitative measurement of tissue oxygen tension (pO₂) under hyperbaric conditions remains technically very challenging.</p><p><strong>Methods: </strong>We developed a specialized small-animal hyperbaric chamber compatible with in vivo electron paramagnetic resonance (EPR) oximetry using customized OxyTrack oxygen detectors. Up to two detectors were implanted simultaneously to measure pO₂ in skeletal muscle and tumor tissue in mice. Animals were exposed to air (21% O₂) and 100% O₂ at both normobaric pressure and 2 atmospheres absolute (ATA) in a stepwise protocol.</p><p><strong>Results: </strong>The chamber operated safely and stably up to 2 ATA, enabling continuous real-time pO₂ monitoring without adverse events and issues with the hardware for up to 90 min. In B16-F10 melanoma, tumor pO₂ increased from ∼9 mmHg at baseline to ∼26 mmHg at 100% O₂ (1 ATA) and ∼50 mmHg at 2 ATA, with partial retention after decompression. In contrast, SCC7 tumors showed minimal responsiveness (∼9-10 mmHg), whereas skeletal muscle demonstrated marked pressure-dependent increases (up to ∼50 mmHg).</p><p><strong>Conclusion: </strong>The small-animal HBO chamber enables real-time, tissue-specific assessment of oxygen dynamics under clinically relevant hyperbaric conditions. The approach could facilitate optimization of HBO protocols and support translational investigation of oxygen-modulated therapies, including radiation and drug responses in solid tumors.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"2019-2028"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13419272/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148295654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneous T₂, T₂*, and R₂' Mapping for Multiple Sclerosis Using Nonlinear Model-Based Reconstruction of Undersampled Radial RARE-EPI MRI.","authors":"Jose Raul Velasquez Vides, Carl J J Herrmann, Thomas Gladytz, Hoby P Hetherington, Hendrik Mattern, Xiaoqing Wang, Jason M Millward, Shahriar Shalikar, Igor Fabian Tellez Ceja, Beate Endemann, Sonia Waiczies, Joseph Kuchling, Friedemann Paul, Georg Rose, Min-Chi Ku, Franz Schmitt, Thoralf Niendorf","doi":"10.1002/mrm.70465","DOIUrl":"10.1002/mrm.70465","url":null,"abstract":"<p><strong>Purpose: </strong>To demonstrate the synergy of undersampled radial 2in1-RARE-EPI acquisition and nonlinear model-based reconstruction for accelerated and simultaneous T₂, T₂*, and R₂' mapping in brains of patients with multiple sclerosis (MS).</p><p><strong>Methods: </strong>2in1-RARE-EPI combines a RARE module with an EPI module to capture T₂ and T₂* information. Nonlinear model-based reconstruction was applied to estimate T₂, T₂* maps directly from undersampled k-space data. A retrospective undersampling experiment was conducted to compare nonlinear model-based and parallel imaging compressed sensing (PICS) reconstruction. The proposed approach was validated and compared to reference methods multiecho spin-echo (T₂, MSE) and multiecho gradient-echo (T₂*, MGRE) in a phantom, healthy subjects, and MS patients.</p><p><strong>Results: </strong>2in1-RARE-EPI together with nonlinear model-based reconstruction enabled T₂, T₂*, and R₂' mapping with 7.5-fold scan-time acceleration relative to the references, while addressing key limitations of reference techniques, including long acquisition times, misregistration, motion and off-resonance sensitivity, and the need for calibration scans. Phantom and in vivo validation showed that the parametric maps obtained with this approach were in agreement with the reference methods. Compared with PICS, nonlinear model-based reconstruction showed more consistent spatial detail and accuracy at higher acceleration factors. The proposed method detected small focal lesions in T₂, T₂*, and R₂' maps of MS patients and enabled visualization of the central vein sign.</p><p><strong>Conclusion: </strong>Scan time reduction facilitated by nonlinear model-based reconstruction of 2in1-RARE-EPI provides a technical foundation for enhanced patient compliance, and is a fundamental precursor for broader clinical studies on the potential of T₂, T₂*, and R₂' as imaging biomarkers.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1872-1892"},"PeriodicalIF":3.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13419268/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148278097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}