Magnetic Resonance Materials in Physics, Biology and Medicine最新文献

{"title":"Self-supervised learning for MRI reconstruction: a review and new perspective.","authors":"Xinzhen Li, Jinhong Huang, Guanglong Sun, Zihan Yang","doi":"10.1007/s10334-025-01274-y","DOIUrl":"https://doi.org/10.1007/s10334-025-01274-y","url":null,"abstract":"<p><strong>Objective: </strong>To review the latest developments in self-supervised deep learning (DL) techniques for magnetic resonance imaging (MRI) reconstruction, emphasizing their potential to overcome the limitations of supervised methods dependent on fully sampled k-space data.</p><p><strong>Background: </strong>While DL has significantly advanced MRI, supervised approaches require large amounts of fully sampled k-space data for training-a major limitation given the impracticality and expense of acquiring such data clinically. Self-supervised learning has emerged as a promising alternative, enabling model training using only undersampled k-space data, thereby enhancing feasibility and driving research interest.</p><p><strong>Methods: </strong>We conducted a comprehensive literature review to synthesize recent progress in self-supervised DL for MRI reconstruction. The analysis focused on methods and architectures designed to improve image quality, reduce scanning time, and address data scarcity challenges, drawing from peer-reviewed publications and technical innovations in the field.</p><p><strong>Conclusions: </strong>Self-supervised DL holds transformative potential for MRI reconstruction, offering solutions to data limitations while maintaining image quality and accelerating scans. Key challenges include robustness across diverse anatomies, standardization of validation, and clinical integration. Future research should prioritize hybrid methodologies, domain-specific adaptations, and rigorous clinical validation. This review consolidates advancements and unresolved issues, providing a foundation for next-generation medical imaging technologies.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144497469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Open-source, customizable phantom for low-field magnetic resonance imaging.","authors":"Kalina V Jordanova, Stephen E Russek, Kathryn E Keenan","doi":"10.1007/s10334-025-01270-2","DOIUrl":"https://doi.org/10.1007/s10334-025-01270-2","url":null,"abstract":"<p><strong>Objective: </strong>This study aimed to describe important criteria for phantom design, while designing an open-source phantom that uses accessible materials and fabrication processes, and that can be easily reproduced and modified by others in the MRI research community.</p><p><strong>Materials and methods: </strong>We enumerate considerations related to designing a phantom based on literature and previous experience. We design and use an open-source phantom on a low-field MRI system. The phantom was 3D printed and assembled, and the imaged samples were made from commonly available materials. T1-weighted and T2-weighted axial and coronal images were acquired at 64 mT, and signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and geometric distortion along one dimension were assessed for each image.</p><p><strong>Results: </strong>Two iterations of the phantom design were made to improve the construction materials and overall form factor for imaging. T1-weighted and T2-weighted images showed contrast between samples and background. T2-weighted images had an 8-10× increase in SNR and CNR compared to T1-weighted images. Geometric distortion measurements were within one-pixel spacing for all scans.</p><p><strong>Discussion: </strong>An open-source phantom was created to assess MRI scans at low-field. Future users may modify the phantom to suit their needs. User-designed inserts can be added, allowing for validation of many MRI-related measurements.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144484885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison between fast-interrupted steady-state (FISS) and rapid water-excitation pulses for fat signal suppression in free-running whole-heart MRI at 1.5 T.","authors":"Yasaman Safarkhanlo, Jérôme Yerly, Mariana B L Falcão, Adèle L C Mackowiak, Davide Piccini, Matthias Stuber, Bernd Jung, Christoph Gräni, Jessica A M Bastiaansen","doi":"10.1007/s10334-025-01273-z","DOIUrl":"https://doi.org/10.1007/s10334-025-01273-z","url":null,"abstract":"<p><strong>Background: </strong>Free-running whole-heart MRI using balanced steady-state free precession (bSSFP) sequences offer high SNR and myocardial tissue contrast. However, an inadequate fat signal suppression may introduce artifacts and is particularly challenging with non-Cartesian readouts. The aim of this study was to evaluate different fat-signal suppression methods for whole-heart free-running MRI at 1.5 T using numerical simulations, phantom, and cardiac MRI experiments without the use of contrast agents.</p><p><strong>Methods: </strong>Binomial off-resonant rectangular (BORR), lipid insensitive binomial off-resonant RF excitation (LIBRE), and lipid insensitive binomial off-resonant (LIBOR) pulses were implemented within a 3D radial bSSFP sequence. Their pulse parameters were optimized for fat signal suppression at 1.5 T using simulations and phantom experiments. Optimized protocols, along with a free-running fast interrupted steady-state (FISS) and non-fat suppressed bSSFP sequence, were used to acquire phantom and cardiac data in five volunteers. SAR values were recorded. The SNR and CNR_Water-Fat were measured in phantom data, while SNR and CNR_{Blood-Myocardium} were quantified in volunteers using reconstruction without motion correction. Motion-resolved reconstructions were used for qualitative assessments. Statistical differences were analyzed using one-way ANOVA.</p><p><strong>Results: </strong>LIBOR had the highest CNR_Water-Fat (276.8 ± 2.5) in phantoms, followed by LIBRE (268.1 ± 2.6), BORR (249.9 ± 2.2), and FISS (212.7 ± 2.7), though these differences were not statistically significant (p > 0.05). In volunteers, BORR had the highest SNR in the ventricular blood pool (17.0 ± 1.5), and LIBRE had the highest CNR_Blood-Fat (29.4 ± 9.3). FISS had the highest CNR_{Blood-Myocardium} (29.0 ± 8.9), but the differences were not significant (p > 0.05). Motion-resolved cardiac imaging showed comparable quality across all fat-suppressed sequences, with no significant streaking artifacts observed. Free-running bSSFP with LIBOR required the lowest SAR, up to a sixfold decrease compared with FISS.</p><p><strong>Conclusion: </strong>The tested sequences performed similarly in SNR and CNR but LIBOR offered the lowest SAR, making it a promising candidate for applications where RF energy deposition is a concern.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144475835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Open-source cardiac magnetic resonance fingerprinting.","authors":"Patrick Schuenke, Catarina Redshaw Kranich, Max Lutz, Jakob Schattenfroh, Matthias Anders, Philine Reisdorf, Jeanette Schulz-Menger, Ingolf Sack, Jesse Hamilton, Nicole Seiberlich, Christoph Kolbitsch","doi":"10.1007/s10334-025-01269-9","DOIUrl":"10.1007/s10334-025-01269-9","url":null,"abstract":"<p><strong>Purpose: </strong>Cardiac magnetic resonance fingerprinting (cMRF) is a powerful quantitative imaging technique that provides multi-parametric diagnostic information. Here, we introduce an open-source framework for cardiac MRF including open-source pulse sequences, image reconstruction, and parameter estimation tools that are needed for the processing of the data.</p><p><strong>Methods: </strong>A 2D cMRF sequence with a variable-density spiral readout is implemented using the open-source and vendor-agnostic sequence format Pulseq. Cardiac triggering is used to synchronize acquisition with the rest period of the heart. <math><msub><mi>T</mi> <mn>1</mn></msub> </math> inversion and <math><msub><mi>T</mi> <mn>2</mn></msub> </math> preparation pulses are added to ensure accurate parameter estimation. Data acquisition is carried out over 15 heartbeats. The images showing the signal changes over time are reconstructed and matched to a pre-calculated signal dictionary. In addition to the cMRF sequence, spin-echo reference sequences for quality control in phantoms are provided. The method is evaluated in phantom experiments using a T1MES phantom on four different scanners. In vivo experiments were performed to compare the open-source cMRF sequence with a vendor-specific cMRF sequence and clinical sequences used for <math><msub><mi>T</mi> <mn>1</mn></msub> </math> and <math><msub><mi>T</mi> <mn>2</mn></msub> </math> mapping of the heart. Three volunteers were imaged on two different scanners.</p><p><strong>Results: </strong>The error of <math><msub><mi>T</mi> <mn>1</mn></msub> </math> and <math><msub><mi>T</mi> <mn>2</mn></msub> </math> over all tissue types present in the T1MES phantom was comparable between all four scanners and on average 4.50 ± 2.48%. <math><msub><mi>T</mi> <mn>1</mn></msub> </math> and <math><msub><mi>T</mi> <mn>2</mn></msub> </math> maps obtained in vivo were comparable between the open-source and vendor-specific implementation of cMRF.</p><p><strong>Conclusion: </strong>The proposed open-source cMRF implementation enables accurate parameter estimation across multiple different scanners. Sequence files, image reconstruction, and parameter estimation scripts are available for reproducible quantitative MRI.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144340254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reproducibility and quality assurance in MRI.","authors":"Tony Stöcker, Kathryn E Keenan, Florian Knoll, Nikos Priovoulos, Martin Uecker, Maxim Zaitsev","doi":"10.1007/s10334-025-01271-1","DOIUrl":"https://doi.org/10.1007/s10334-025-01271-1","url":null,"abstract":"","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144317344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ESMRMB 2025 focus topic: cycle of quality-from concept to clinical and scientific impact.","authors":"Thomas Küstner, Roy Haast, Nikos Priovoulos, Patricia Clement, Daniel Pinto Dos Santos","doi":"10.1007/s10334-025-01272-0","DOIUrl":"https://doi.org/10.1007/s10334-025-01272-0","url":null,"abstract":"","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144293978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utility of multiparametric MRI including T1/T2 mapping and IVIM/diffusion imaging for the evaluation of non-obstructive azoospermia.","authors":"Hiram Shaish, Sachin Jambawalikar, Firas Ahmed, Patrick Quarterman, Maggie Fung, Mitsuharu Miyoshi, Christopher Sayegh, Leon Telis, Valary Raup, George Wayne, Albert Ha, Joseph P Alukal","doi":"10.1007/s10334-025-01267-x","DOIUrl":"https://doi.org/10.1007/s10334-025-01267-x","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Introduction and objectives: &lt;/strong&gt;The management of non-obstructive azoospermia (NOA) remains challenging because no predictive test for the presence of localized spermatogenesis exists. Previous work considered MRI techniques, such as spectroscopy (MRS) and diffusion weighted imaging (DWI), in this role. We report here data from a prospective study evaluating additional advanced MRI sequences for predicting spermatogenesis in patients with NOA.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;9 fertile volunteers and 18 men with NOA were prospectively recruited. Each participant underwent a novel multi-parametric MRI consisting of T1 and T2 mapping as well as intravoxel incoherent motion (IVIM) and diffusion weighted imaging (DWI). A single radiologist drew representative regions of interest on the best quality images for each sequence and recorded the mean values. Sperm extraction procedure results were recorded. Two-end points were evaluated: NOA versus fertile controls and the presence of viable sperm within the NOA cohort. The data were analyzed per patient. Nonparametric and logistic regression statistical analysis were used.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;9 fertile men (median 43 years old, 2 children) and 18 men with NOA (median 37 years old, 0 children) were studied. 11 of the 18 men with NOA had testicle sampling. 4 men with NOA had viable sperm. Follicle-stimulating hormone and testosterone levels were not significantly different among NOAmen with and without sperm (p-value = 0.58 and 0.25). Nonparametric analysis with the Wilcoxon rank sum test showed T2 relaxation time was lower among NOA patients (median 101 vs 135 ms, p-value = 0.002), apparent diffusion coefficient (ADC) was higher among NOA patients (median 127.9 vs. 106.7 × 10&lt;sup&gt;-5&lt;/sup&gt; mm&lt;sup&gt;2&lt;/sup&gt;/sec, p-value = 0.005). T1 relaxation time, alpha (Water diffusion heterogeneity index), D (IVIM-based apparent diffusion coefficient), DDC (Distributed diffusion coefficient) and D* (pseudodiffusion) were also significantly different. On logistic regression analysis, both T2 and ADC were associated with NOA; The odds of NOA decreased by 6% for each msec increase in T2 (p-value = 0.02) while the odds of NOA increased by 11% for each 10⁻&lt;sup&gt;5&lt;/sup&gt; mm&lt;sup&gt;2&lt;/sup&gt;/sec increase in ADC, (p-value = 0.02). T2 yielded a larger area under the receiver operating characteristic curve than ADC (0.87 versus 0.84). Alpha, D, DDC and D* also predicted NOA. Amongst men with NOA who underwent testicle sampling, T2 was lower in testicles of patients with no sperm retrieved (median 73 vs 134. msec, p-value = 0.02). The remaining variables were not significantly different between the cohorts.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;In spite of the small sample size, particularly for men with NOA who underwent sperm extraction, these results suggest that several novel MRI parameters, such as T2 relaxation time and certain IVIM/DWI parameters, are able to distinguish between fertile men and men with NOA ","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144293979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Agreement of image quality metrics with radiological evaluation in the presence of motion artifacts.","authors":"Elisa Marchetto, Hannah Eichhorn, Daniel Gallichan, Julia A Schnabel, Melanie Ganz","doi":"10.1007/s10334-025-01266-y","DOIUrl":"10.1007/s10334-025-01266-y","url":null,"abstract":"<p><strong>Objective: </strong>Reliable image quality assessment is crucial for evaluating new motion correction methods for magnetic resonance imaging. We compare the performance of common reference-based and reference-free image quality metrics on unique datasets with real motion artifacts, and analyze the metrics' robustness to typical pre-processing techniques.</p><p><strong>Materials and methods: </strong>We compared five reference-based and five reference-free metrics on brain data acquired with and without intentional motion (2D and 3D sequences). The metrics were recalculated seven times with varying pre-processing steps. Spearman correlation coefficients were computed to assess the relationship between image quality metrics and radiological evaluation.</p><p><strong>Results: </strong>All reference-based metrics showed strong correlation with observer assessments. Among reference-free metrics, Average Edge Strength offers the most promising results, as it consistently displayed stronger correlations across all sequences compared to the other reference-free metrics. The strongest correlation was achieved with percentile normalization and restricting the metric values to the skull-stripped brain region. In contrast, correlations were weaker when not applying any brain mask and using min-max or no normalization.</p><p><strong>Discussion: </strong>Reference-based metrics reliably correlate with radiological evaluation across different sequences and datasets. Pre-processing significantly influences correlation values. Future research should focus on refining pre-processing techniques and exploring approaches for automated image quality evaluation.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A dedicated phantom for exploring the interplay of fat and paramagnetic substances in quantitative susceptibility mapping.","authors":"Simon Graf, Josefine Trapp, Maik Rothe, Alexander Gussew, Walter A Wohlgemuth, Andreas Deistung","doi":"10.1007/s10334-025-01261-3","DOIUrl":"10.1007/s10334-025-01261-3","url":null,"abstract":"<p><strong>Objective: </strong>Accurate quantitative tissue characterization in organs with considerable fat content, like the liver, requires thorough understanding of fat's influence on the MR signal. To continue the investigations into the use of quantitative susceptibility mapping (QSM) in abdominal regions, we present a dedicated phantom that replicates liver-like conditions in terms of effective transverse relaxation rates (R₂*) and proton density fat fractions.</p><p><strong>Materials and methods: </strong>The spherical agar phantom consists of nine smaller spheres (diameter: 3 cm) doped with a paramagnetic substance (iron nanoparticles or manganese chloride) and fat (peanut oil), embedded in a large agar sphere (diameter: 14 cm), ensuring no barriers exist between the enclosed spheres and their surrounding medium. Concentrations were selected to represent both healthy and pathologic conditions. 3T MRI measurements for relaxometry, fat-water imaging, and QSM were conducted with the head coil and for ¹H-spectroscopy with the knee coil at three time points, including a scan-rescan assessment and a follow-up measurement 14 months later.</p><p><strong>Results: </strong>The phantoms' relaxation and magnetic properties are in similar range as reported for liver tissue. Substantial alterations in local field and susceptilibty maps were observed in regions with elevated fat and iron content, where fat correction of the local field via chemical shift-encoded reconstruction effectively reduced streaking artifacts in susceptibility maps and substantially increased susceptibility values. Linear regression analysis revealed a consistent linear relationship between R₂* and magnetic susceptibility, as well as iron concentration and magnetic susceptibility. The relaxation, fat, and susceptibility measurements remained stable across scan-rescan assessment and long-term follow-up.</p><p><strong>Discussion: </strong>We developed a versatile phantom to study fat-iron interactions in abdominal imaging, facilitating the optimization and comparison of susceptibility processing methods in future research.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144199470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ESMRMB 2025 focus topic: cycle of translation.","authors":"Claudia Lenz, Melanie Bauer, Christian Langkammer, Hendrik Mattern, Francesco Santini","doi":"10.1007/s10334-025-01265-z","DOIUrl":"https://doi.org/10.1007/s10334-025-01265-z","url":null,"abstract":"","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}