Magnetic Resonance in Medicine最新文献

{"title":"Fast, motion-robust MR elastography with distributed, generalized encoding","authors":"Mary K. Kramer,&nbsp;Alex M. Cerjanic,&nbsp;Curtis L. Johnson","doi":"10.1002/mrm.30631","DOIUrl":"10.1002/mrm.30631","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>MR elastography (MRE) data are susceptible to poor quality often caused by long scan times and subject motion, due in part to the specific data sampling requirements for determining motion fields to estimate mechanical properties. By reformulating how motion is encoded and estimated, a more efficient and flexible MRE method that allows for accelerated acquisition and motion robustness is established.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Theory and Methods</h3>\u0000 \u0000 <p>A novel motion-encoding technique was implemented that uses fully distributed sampling directions in an optimized encoding matrix to collect data efficiently. These data are used in an optimization algorithm to estimate harmonic displacement fields. Simulations and in vivo brain MRE data demonstrate the performance of distributed encoding compared with traditional encoding. Estimation of motion from partial data sets after retrospective volume rejection demonstrates new capabilities for robustness to subject motion.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The proposed method achieved significant acceleration over standard methods, allowing for whole-brain 3D MRE in under 1 min, while maintaining an average 2% difference from traditionally sampled images. If scan time is not prospectively shortened, retrospective removal of images from the data set, such as those corrupted by motion, maintains less than 10% voxel-wise error after removing up to half of a complete data set.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Through prospective reduction in sampling, reducing acquisition time, and retrospective volume rejection, this distributed encoding technique adds significant capability and flexibility to MRE acquisitions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2113-2128"},"PeriodicalIF":3.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144608721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing computation speed and accuracy in deep image prior-based parameter mapping.","authors":"Max Hellström, Polina Kurtser, Tommy Löfstedt, Anders Garpebring","doi":"10.1002/mrm.30630","DOIUrl":"https://doi.org/10.1002/mrm.30630","url":null,"abstract":"<p><strong>Purpose: </strong>To make Deep Image Prior (DIP)-based parameter mapping faster, more accurate, and suitable for clinical applications, with added support for multislice and 3D datasets.</p><p><strong>Methods: </strong>DIP leverages the inherent structure of an untrained image generator to address various inverse imaging tasks, including denoising. In this study, we enhance DIP-based denoising for parameter mapping with warm-start across neighboring image slices and different patient subjects. This approach leverages spatial similarity to reduce computation time. Additionally, we introduce an early-stopping criterion that selects the denoising level based on MRI signal noise. We further investigate uncertainty calibration through dropout probability tuning to address issues with miscalibrated uncertainty estimates from Monte Carlo dropout. Furthermore, we explore reducing computation time by tuning learning rates and network complexity.</p><p><strong>Results: </strong>We show that reusing image generator weights with warm-start significantly accelerates the denoising of large datasets, reducing computation time by 78% to 95% across various tasks. The early stopping approach proved effective, eliminating the need to manually select the number of optimization steps. Dropout probability tuning helps mitigate the issue of miscalibrated uncertainty, though further refinements are necessary, particularly to achieve better calibration on a per-pixel level. Additionally, tuning learning rates and network complexity provided valuable insights into optimizing the model for different tasks.</p><p><strong>Conclusion: </strong>The proposed developments enable DIP-based parameter mapping to become faster, more accurate, and, consequently, more practical and scalable for clinical applications involving larger datasets.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144608720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneous liver T1, T2, and ADC MR fingerprinting using optimized motion-compensated diffusion preparations: An initial validation on volunteers","authors":"C. Velasco,&nbsp;C. Castillo-Passi,&nbsp;N. Chaher,&nbsp;D. C. Karampinos,&nbsp;P. Irarrazaval,&nbsp;A. Phinikaridou,&nbsp;R. M. Botnar,&nbsp;C. Prieto","doi":"10.1002/mrm.30622","DOIUrl":"10.1002/mrm.30622","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To develop a novel MR fingerprinting sequence using optimized motion-compensated diffusion preparations for simultaneous T₁, T₂, and ADC quantification of liver tissue in a single breath-held scan.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A radial spoiled gradient echo acquisition with magnetization preparation modules for T₁, T_2, and ADC encoding is proposed. To compensate for the signal voids generated by the diffusion preparation, the combination of (1) a breath-held scan, (2) peripheral pulse signal triggering, and (3) an optimized motion-compensated diffusion-preparation module is employed. Phantom experiments were performed to test the accuracy of the technique. The sequence was evaluated in 11 healthy subjects in comparison to conventional mapping techniques. Additional in vivo repeatability assessment experiments were performed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>T₁, T₂, and ADC quantification showed good correlation (r² &gt; 0.9 for all cases) with reference maps in phantoms and good agreement in vivo against clinical scans (bias not significantly different from zero). A peripheral pulse trigger delay of 200 ms was used to reduce cardiovascular motion artifacts. The repeatability tests prove a low interscan coefficient of variation and a high intraclass correlation coefficient of greater than 0.9 for all cases.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Simultaneous quantification of T₁, T₂, and ADC in liver tissue in a single MR fingerprinting scan of ˜16 s has been proposed, enabling a comprehensive evaluation of hepatic disease through co-registered multiparametric imaging. Further studies are warranted to test this approach in patients with suspected diffuse liver disease to evaluate its potential for liver tissue characterization and tumor staging.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2173-2189"},"PeriodicalIF":3.0,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30622","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144600924","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":"Fast MR signal simulations of microvascular and diffusion contributions using histogram-based approximation and recurrent neural networks","authors":"Thomas Coudert,&nbsp;Maitê Silva Martins Marçal,&nbsp;Aurélien Delphin,&nbsp;Antoine Barrier,&nbsp;Lila Cunge,&nbsp;Loïc Legris,&nbsp;Jan M. Warnking,&nbsp;Benjamin Lemasson,&nbsp;Emmanuel L. Barbier,&nbsp;Thomas Christen","doi":"10.1002/mrm.30629","DOIUrl":"10.1002/mrm.30629","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Accurate MR signal simulation, including microvascular structures and water diffusion, is crucial for MRI techniques like fMRI BOLD modeling and MR vascular Fingerprinting (MRF), which use susceptibility effects on MR signals for tissue characterization. However, integrating microvascular features and diffusion remains computationally challenging, limiting the accuracy of the estimates. Using advanced modeling and deep neural networks, we propose a novel simulation tool that efficiently accounts for susceptibility and diffusion effects.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used dimension reduction of magnetic field inhomogeneity matrices combined with deep learning methodology to accelerate the simulations while maintaining their accuracy. We validated our results through an in silico study against a reference method and in vivo MRF experiments.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>This approach accelerates MR signal generation by a factor of almost 13 000 compared to previously used simulation methods while preserving accuracy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The MR-WAVES method allows fast generation of MR signals accounting for microvascular structures and water-diffusion contribution.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2234-2248"},"PeriodicalIF":3.0,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30629","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144584289","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":"Development of an echo-shifted, multi-echo, gradient-echo sequence for T2* quantification of slow-relaxing water pools","authors":"Seonyeong Shin,&nbsp;Ana-Maria Oros-Peusquens,&nbsp;Seong Dae Yun,&nbsp;Ezequiel Farrher,&nbsp;N. Jon Shah","doi":"10.1002/mrm.30624","DOIUrl":"10.1002/mrm.30624","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Although conventional multi-echo gradient-echo (GRE) sequences effectively quantify short and intermediate T₂* in brain tissue, and general interest in cerebrospinal fluid (CSF) is growing due to its association with the glymphatic system, quantifying T₂* in CSF remains underexplored. Accurate quantification of the slow-relaxing water pools requires imaging at long echo times, significantly increasing acquisition time. This study proposes a novel sequence capable of quantifying the entire range of T₂* without prolonged acquisition time, mapping T₂* in both CSF and brain tissue.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The proposed echo-shifted, multi-echo GRE (ES-mGRE) combines the conventional multi-echo GRE sequence with an echo-shifting technique. Additional gradients are introduced, producing echoes in the next sub–repetition time interval.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>ES-mGRE generates artifact-free images at both short and long echo times without extending acquisition time. Increasing the area of the additional gradients enhances diffusion sensitivity, allowing simultaneous quantification of T₂* and <i>D</i> in CSF. The mean T₂* of white matter and gray matter is 55.9 ms and 51.5 ms at 3 T, respectively. The mean T₂* in the ventricles is 234.5 ms. The simultaneously quantified mean <i>D</i> value of 3.07 μm²/ms is closely aligned with the reference diffusivity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>We demonstrate that the proposed ES-mGRE sequence can effectively quantify the T₂* of both CSF and brain tissue while also providing simultaneous diffusion information.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2057-2070"},"PeriodicalIF":3.0,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30624","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144567619","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":"Fast and High-Resolution luminal water imaging for prostate cancer diagnosis","authors":"Hao Li,&nbsp;Nikita Sushentsev,&nbsp;Dimitri Kessler,&nbsp;Shaohang Li,&nbsp;Kang-Lung Lee,&nbsp;Andrew Nicholas Priest,&nbsp;Ferdia A. Gallagher,&nbsp;Tristan Barrett","doi":"10.1002/mrm.30628","DOIUrl":"10.1002/mrm.30628","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study aims to address the limitation of long acquisition times in luminal water imaging (LWI), a promising noninvasive MRI technique for prostate cancer detection and grading, by implementing an accelerated multi-echo spin-echo method termed T2 mapping using echo merging plus k-t undersampling with reduced flip angles (<i>TEMPURA)</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>TEMPURA enables faster acquisition through echo merging, <i>k</i>-t undersampling, and reduced refocusing flip angles. A prospective study was conducted on 24 patients (age 59–75 years) with biopsy-proven prostate cancer. Imaging was performed on a 3 T MRI system, comparing two TEMPURA-based LWI sequences—Fast (standard resolution) and High-Resolution (HR, doubled spatial resolution)—against a standard LWI sequence (Standard). Luminal water fraction and five additional parameters were compared across the methods. Statistical analyses included Spearman rank correlation, Wilcoxon rank sum test, receiver operating characteristic analysis, Bland–Altman plots, and Delong tests.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Compared to Standard, Fast reduced the acquisition time from 8.3 to 2.8 min, whereas HR reduced it to 5.4 min and doubled spatial resolution. Both Fast and HR showed high correlation with Standard for luminal water fraction (<i>r</i> = 0.97/0.90 in peripheral zone, <i>r</i> = 0.91/0.93 in transition zone), with low bias (0.014/0.018 in peripheral zone, 0.024/0.024 in transition zone) and no significant differences (<i>p</i> = 0.05–0.84/0.08–0.51). No significant difference was observed in area under the curve values between Fast/HR and Standard among all parameters (<i>p</i> = 0.05–0.87).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The acceleration method greatly reduced the acquisition time and increased the spatial resolution of LWI. Compared with the Standard acquisition, both the Fast and HR methods showed a high correlation for LWI measurements and consistent diagnostic performance in detecting malignant lesions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2150-2157"},"PeriodicalIF":3.0,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30628","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144567620","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":"Cardiac diffusion kurtosis imaging in the human heart in vivo using 300 mT/m gradients","authors":"Maryam Afzali,&nbsp;Sam Coveney,&nbsp;Lars Mueller,&nbsp;Sarah Jones,&nbsp;Fabrizio Fasano,&nbsp;C. John Evans,&nbsp;Irvin Teh,&nbsp;Erica Dall'Armellina,&nbsp;Filip Szczepankiewicz,&nbsp;Derek K. Jones,&nbsp;Jürgen E. Schneider","doi":"10.1002/mrm.30626","DOIUrl":"10.1002/mrm.30626","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Diffusion tensor imaging (DTI) is commonly used in cardiac diffusion magnetic resonance imaging (dMRI). However, the tissue's microstructure (cells, membranes, etc.) restricts the movement of the water molecules, making the spin displacements deviate from Gaussian behavior. This effect may be observed with diffusion kurtosis imaging (DKI) using sufficiently high b-values (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mn&gt;450&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mtext&gt;s/mm&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ mathrm{b}&gt;450kern0.2em mathrm{s}/{mathrm{mm}}^2 $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;), which are presently outside the realm of routine cardiac dMRI due to the limited gradient strength of clinical scanners. The Connectom scanner with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;G&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;max&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;300&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;mT&lt;/mi&gt;\u0000 &lt;mo&gt;/&lt;/mo&gt;\u0000 &lt;mi&gt;m&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {mathrm{G}}_{mathrm{max}}=300kern0.2em mathrm{mT}/mathrm{m} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; enables high b-values at echo times (TE) similar to DTI on standard clinical scanners, therefore facilitating cardiac DKI in humans.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Cardiac-gated, second-order motion-compensated dMRI was performed with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;max&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2100-2112"},"PeriodicalIF":3.0,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30626","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144553926","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":"pTx-Pulseq in hybrid sequences: Accessible and advanced hybrid open-source MRI sequences on Philips scanners","authors":"Thomas H. M. Roos,&nbsp;Edwin Versteeg,&nbsp;Mark Gosselink,&nbsp;Hans Hoogduin,&nbsp;Kyung Min Nam,&nbsp;Nicolas Boulant,&nbsp;Vincent Gras,&nbsp;Franck Mauconduit,&nbsp;Dennis W. J. Klomp,&nbsp;Jeroen C. W. Siero,&nbsp;Jannie P. Wijnen","doi":"10.1002/mrm.30601","DOIUrl":"10.1002/mrm.30601","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To enhance the accessibility of advanced pulse sequences, or parts thereof, through the open-source Pulseq framework. This work extends the Pulseq framework to Philips MRI systems and incorporates dynamic parallel-transmit (pTx) capabilities within the constraints of the existing Pulseq format. This enables the hybrid use of Pulseq sequences within the native vendor's scans, leveraging the combined strengths of both approaches. We showcase a new possibility of these techniques: the use of a portable cross-vendor universal pulse (UP) excitation in a native scan.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>pTx-Pulseq was implemented to add full dynamic pTx within the Pulseq specification. We developed a Pulseq interpreter for Philips systems, supporting both Pulseq-only and hybrid sequences. The hybrid mode was used to integrate a UP from the PASTeUR package into a vendor's native scan. Simulation experiments, safety validations, field measurements, and imaging experiments in phantom and in vivo were conducted to verify the interpreter's and UP's functionality.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The interpreter executed Pulseq sequences on a Philips 7T system, accurately reproducing gradient waveforms and dynamic pTx sequences. The real-time safety systems operated correctly. Phantom and in vivo scans demonstrated comparable image quality to native sequences, validating the effectiveness of the interpreter and the successful cross-vendor use of universal pulses.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The successful cross-vendor application of a universal pulse through pTx-Pulseq in a hybrid sequence demonstrates how advanced MRI techniques can be made accessible. This not only highlights the flexibility and extensibility of Pulseq but also sets the stage for rapid clinical translation of innovative imaging techniques.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"1946-1962"},"PeriodicalIF":3.0,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30601","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144553927","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":"Myelin water and tensor-valued diffusion imaging: (How) are they related?","authors":"Sharada Balaji,&nbsp;Adam V. Dvorak,&nbsp;Neale Wiley,&nbsp;Erin L. MacMillan,&nbsp;Anthony Traboulsee,&nbsp;Irene M. Vavasour,&nbsp;Guillaume Gilbert,&nbsp;G. R. Wayne Moore,&nbsp;David K. B. Li,&nbsp;Cornelia Laule,&nbsp;Alex L. MacKay,&nbsp;Shannon Kolind","doi":"10.1002/mrm.30620","DOIUrl":"10.1002/mrm.30620","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Conventional MRI offers limited insight into specific characteristics of central nervous system tissue, whereas quantitative MRI measures can provide more detailed information about different aspects of microstructure. A multi-metric approach involving multiple quantitative measures may improve our understanding of healthy tissue and pathology. Previous work shows myelin water fraction (MWF) is related to fractional anisotropy (FA), but this relationship is complicated by confounding factors that may be resolved using tensor-valued diffusion imaging, which yields measurements of microscopic FA (μFA) and tissue heterogeneity (C_MD). Our aims were to better understand how measures from myelin water and tensor-valued diffusion imaging relate to one another, and to demonstrate how these measures can be used to characterize microstructure in both healthy white matter and pathological changes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We assessed the relationship between MWF, FA, μFA, and C_MD from 25 healthy individuals through atlas comparison, correlation analysis, and tract profiling. We also applied z-score analysis and tract profiling in five people with multiple sclerosis (MS) to evaluate the multi-metric utility of these measures in assessing pathology.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Although correlation analysis showed moderate, but potentially misleading relationships between metrics, tract profiling showed consistent tract-specific pattern differences between metrics in healthy tissue. In MS, MWF, μFA, and C_MD were the most sensitive to pathological changes, showing regions of abnormality even in normal-appearing white matter and along lesional tracts, and highlighting different types of damage.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Using MWF, μFA, and C_MD to separately assess myelination, anisotropy, and tissue heterogeneity enhances our ability to investigate development, aging, disease, and injury.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2038-2056"},"PeriodicalIF":3.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30620","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144540754","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":"Feasibility of strong diffusion encoding and fast readout using a plug-and-play head gradient insert at 7 T","authors":"G. C. Arends,&nbsp;E. Versteeg,&nbsp;A. De Luca,&nbsp;F. Marc,&nbsp;T. H. M. Roos,&nbsp;D. W. J. Klomp,&nbsp;M. Froeling,&nbsp;J. C. W. Siero,&nbsp;C. M. W. Tax","doi":"10.1002/mrm.30613","DOIUrl":"10.1002/mrm.30613","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Diffusion weighting is achieved by the application of external field gradients typically for tens of milliseconds, during which the signal also substantially decays due to inherent T₂ relaxation. Employing strong gradients will shorten the echo time (TE) and increase the signal-to-noise ratio. This study demonstrates a proof-of-principle of using an ultrastrong head gradient insert for diffusion MRI at 7 T.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A lightweight (45 kg) single-axis gradient coil operating in the <i>z</i>-direction was interfaced with a 7 T system and operated as an additional fourth-gradient axis to the whole-body gradient setup. Several diffusion MRI experiments were conducted to compare acquisitions taken with a gradient insert operating at full capacity (200 mT/m and 1300 T/m/s) to those using conventional gradient strengths (40–80 mT/m and 200 T/m/s).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>A shorter TE of (28.8, 32.4, 38.5, 48.7) ms was achieved using the insert gradient at full capability for readout and diffusion encoding, compared to (49.7, 54.5, 65.9, 85.5) ms (80 mT/m) or (59.9, 68.8, 88.3, 120.9) ms (40 mT/m) for <i>b</i> = (0, 500, 1000, 3000, 10 000) s/mm² using conventional gradient strength. A SNR increase for all <i>b</i>-value acquisitions was observed. When using strong gradients for readout, TE was shortened by 20 ms, and a lower degree of geometrical distortions was observed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The results illustrate a successful proof-of-concept for performing diffusion MRI using a plug-and-play head gradient insert at 7 T. Use of low-cost gradient inserts could make advanced diffusion MRI experiments more widely available.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 5","pages":"2304-2316"},"PeriodicalIF":3.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30613","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144540753","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}