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

{"title":"Fast 3D-MRSI using sparse acquisition and 4D compressed sensing reconstruction.","authors":"Jian-Xiong Wang","doi":"10.1007/s10334-025-01301-y","DOIUrl":"10.1007/s10334-025-01301-y","url":null,"abstract":"<p><strong>Background: </strong>Magnetic Resonance Spectroscopic Imaging (MRSI), also known as Chemical Shift Imaging (CSI), is a pivotal tool in both clinical and preclinical metabolic research. Traditional MRSI offers high sensitivity to weak metabolites and covers a wide spectral bandwidth. However, the large number of RF excitations required for fully sampled 3D-MRSI acquisitions renders it impractical for hyperpolarized (HP) MRI applications, especially given the rapid signal decay and non-renewable magnetization of HP agents such as [1-¹³C]pyruvate.</p><p><strong>Purpose: </strong>This study aims to develop and validate an accelerated MRSI method that can preserve broad spectral bandwidth and weak metabolite detectability without aliasing, overcoming limitations of fast MRSI techniques such as echo-planar spectroscopic imaging (EPSI), which typically cause narrower spectral bandwidth and can suffer from spectral aliasing.</p><p><strong>Methods: </strong>We implemented a sparsely sampled 3D-MRSI pulse sequence on an MRI scanner, acquiring data with large reduction ratios. A 4D compressed sensing (CS) reconstruction algorithm was developed to recover high-resolution spectroscopic data from undersampled measurements. The algorithm jointly reconstructs the three spatial dimensions and the frequency dimension, leveraging sparsity priors and iterative conjugate gradient optimization. The in vivo experiments were performed on a GE 3 T clinical MRI scanner (GE MR750W) using hyperpolarized [1-¹³C]pyruvate in one rat, with two acquisitions (R = 8 and R = 16) performed sequentially.</p><p><strong>Results: </strong>Our method achieved high-quality reconstructions even at acceleration factors of R = 16 and R = 32, corresponding to 6.25 and 3.125% sampling, respectively. The normalized root-mean-square error (nRMSE) and structural similarity index (SSIM) remained low (nRMSE < 4 × 10^-3, SSIM > 0.95) even at high undersampling rates. In vivo experiments using hyperpolarized [1-¹³C]pyruvate in rat kidneys demonstrated the ability to resolve lactate, alanine, pyruvate, and bicarbonate distributions with high spatial and spectral fidelity.</p><p><strong>Conclusion: </strong>The integration of sparse MRSI acquisition and 4D-CS reconstruction enables rapid, high-fidelity MRSI with HP ¹³C-MRSI. This approach reduces acquisition time by up to 32-fold, facilitating dynamic metabolic studies and improving feasibility for routine preclinical and future clinical use.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"253-264"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13124777/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145426515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<ArticleTitle xmlns:ns0=\"http://www.w3.org/1998/Math/MathML\">Motion-robust proton density fat fraction and <ns0:math> <ns0:msup> <ns0:mrow><ns0:msub><ns0:mi>T</ns0:mi> <ns0:mn>2</ns0:mn></ns0:msub> </ns0:mrow> <ns0:mo>∗</ns0:mo></ns0:msup> </ns0:math> mapping in supraclavicular adipose tissue using radial stack-of-stars imaging.","authors":"Johannes Raspe, Jonathan Stelter, Philipp Braun, Daniela Junker, Mingming Wu, Dimitrios C Karampinos","doi":"10.1007/s10334-025-01302-x","DOIUrl":"10.1007/s10334-025-01302-x","url":null,"abstract":"<p><strong>Purpose: </strong>Accurate quantification of proton density fat fraction (PDFF) and <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> in the supracalvicular (SCV) fossa is critical for studying brown adipose tissue (BAT), but is challenged by respiratory motion-induced <math><msub><mi>B</mi> <mn>0</mn></msub> </math> fluctuations. This study compares conventional Cartesian imaging to a radial stack-of-stars (SoS) trajectory, with and without retrospective temporal <math><msub><mi>B</mi> <mn>0</mn></msub> </math> correction, in terms of PDFF and <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> mapping precision.</p><p><strong>Methods: </strong>Motion-induced <math><msub><mi>B</mi> <mn>0</mn></msub> </math> fluctuations and tissue displacement were modeled using a digital anatomical phantom. Both Cartesian and radial SoS trajectories were simulated, with temporal <math><msub><mi>B</mi> <mn>0</mn></msub> </math> correction, relying on oversampling of the k-space center, applied to the radial SoS data. Additionally, repeated in vivo scans were performed in four volunteers using both trajectories. PDFF and <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> were quantified across repetitions.</p><p><strong>Results: </strong>Simulations demonstrated smaller PDFF and <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> errors in radial SoS compared to Cartesian imaging under the influence of simulated motion effects. In the simulations, the mean absolute PDFF error decreased from <math> <msub><mrow><mn>1.07</mn> <mspace></mspace> <mo>%</mo></mrow> <mtext>PDFF</mtext></msub> </math> with Cartesian to <math> <msub><mrow><mn>0.47</mn> <mspace></mspace> <mo>%</mo></mrow> <mtext>PDFF</mtext></msub> </math> with radial SoS, and the <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> error decreased from 7.50 ms to 3.37 ms. In vivo, radial SoS provided higher repeatability for both parameters compared to Cartesian acquisitions, as measured by the inter-scan coefficient of variation. Retrospective temporal <math><msub><mi>B</mi> <mn>0</mn></msub> </math> correction further improved the repeatability of <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> quantification.</p><p><strong>Conclusions: </strong>Radial SoS imaging improves motion robustness and repeatability of PDFF and <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> quantification in the SCV fossa compared to Cartesian acquisitions. Incorporating retrospective temporal <math><msub><mi>B</mi> <mn>0</mn></msub> </math> correction further enhances <math> <msup> <mrow><msub><mi>T</mi> <mn>2</mn></msub> </mrow> <mo>∗</mo></msup> </math> reliability and may strengthen the precision of BAT activation studies.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"237-252"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13124760/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145495785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BOLD fMRI at 9.4T with 3D stack-of-spirals readouts.","authors":"Alejandro Monreal-Madrigal, Denizhan Kurban, Desmond H Y Tse, Dimo Ivanov, Nicolas Boulant, Benedikt A Poser","doi":"10.1007/s10334-025-01298-4","DOIUrl":"10.1007/s10334-025-01298-4","url":null,"abstract":"<p><strong>Objective: </strong>To investigate the use of spiral readouts for sub-millimeter BOLD fMRI at 9.4T and to verify simulations of the BOLD point spread function (PSF) with functional experiments.</p><p><strong>Materials and methods: </strong>Spiral readouts were evaluated through simulations and functional experiments to test their performance in sub-millimeter BOLD fMRI. Both spiral-out and spiral-in readout strategies were considered, with attention to echo time (TE) relative to T₂*.</p><p><strong>Results: </strong>We confirmed that a TE shorter than T₂* can be employed for spiral-out readouts without compromising BOLD sensitivity. The use of shorter TE provided a reduced repetition time (TR), improved temporal signal-to-noise ratio (tSNR), and minimized off-resonance effects.</p><p><strong>Discussion: </strong>Spiral-in readouts were found to be mainly useful for lower-resolution applications at ultra-high field (UHF). In contrast, segmented spiral-out readouts demonstrated strong potential for mesoscopic BOLD fMRI at ultra-high fields (> 7T).</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"201-215"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13124969/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145186214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of tractography parameters for dentato-rubro-thalamic tract reconstruction during pediatric posterior fossa tumor surgery.","authors":"Pien E J Jellema, Karina J Kersbergen, Eelco W Hoving, Maarten H Lequin, Kirsten M van Baarsen, Thomas Lindner, Wouter P Nieuwenhuis, Alberto De Luca, Jannie P Wijnen","doi":"10.1007/s10334-025-01297-5","DOIUrl":"10.1007/s10334-025-01297-5","url":null,"abstract":"<p><strong>Objective: </strong>Intraoperative fiber tractography can help neurosurgeons in localizing eloquent tracts potentially displaced by tumors. In pediatric posterior fossa tumor (pPFT) patients, disturbances to the eloquent dentato-rubro-thalamic tract (DRTT) might contribute to cerebellar mutism syndrome. This study investigates the effect of fiber tractography parameters on DRTT reconstruction in pre- and intraoperative settings.</p><p><strong>Methods: </strong>T1-weighted and diffusion MRI data were acquired from ten pPFT patients and two healthy volunteers. The patients were scanned pre- and intraoperatively. The DRTT was reconstructed using multiple fiber orientation distribution (FOD) and angle thresholds. An expert panel evaluated tract reconstructions to identify optimal parameters in our dataset. The corticospinal tract (CST) served as a control. Relative tract volumes of the DRTT and the CST were calculated.</p><p><strong>Results: </strong>Diffusion MRI data were sufficient for reliable DRTT reconstruction in healthy volunteers. In most pPFT patients, an FOD of 0.01 and a 60° angle threshold were evaluated as optimal for DRTT reconstruction in our dataset. Preoperative DRTT reconstructions showed more reconstructed streamlines and larger relative volumes, particularly in non-decussating tracts. CST reconstructions remained consistent across both timepoints.</p><p><strong>Discussion: </strong>DRTT reconstruction is feasible in pPFT patients before and during surgery. However, inter-subject variability suggests that some patients may require adjusted thresholds for optimal results.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"275-288"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13124821/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145199772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scanner repeatability and reproducibility of qRF-MRF breath-held and free-breathing with pilot tone in the abdomen.","authors":"Madison E Kretzler, Jessie E P Sun, Eduardo Thadeu de Oliveira Correia, Leonardo K Bittencourt, Chris A Flask, Mark A Griswold, Rasim Boyacioglu","doi":"10.1007/s10334-025-01305-8","DOIUrl":"10.1007/s10334-025-01305-8","url":null,"abstract":"<p><strong>Object: </strong>Repeatability and reproducibility are imperative for new Magnetic Resonance Imaging (MRI) methods, such as the quantitative technique MR Fingerprinting (MRF), to be clinically adopted for regular patient usage.</p><p><strong>Materials and methods: </strong>We tested the repeatability and reproducibility of a new free-breathing (FB) quadratic RF phase Magnetic Resonance Fingerprinting (qRF-MRF) with Pilot Tone (PT) navigator in the abdominal cavity with a focus on liver by performing repeat scan-rescan collection comparisons for 8 healthy volunteers on 2 different Siemens Vida 3T scanners at the same site running different software versions.</p><p><strong>Results: </strong>Using Bland-Altman analysis, our results for T1, T2, and T2* establish the repeatability and reproducibility, via the limits of agreement and bias estimations, of the FB qRF-MRF sequence and compare to its breath-held qRF-MRF and clinical standard counterparts across scanners and scan conditions.  DISCUSSION: Based on the bias and limits of agreement of breath-hold and FB qRF-MRF patients can receive reliable and comparable imaging at different sessions for prognosis and treatment planning.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"319-330"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13124824/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145668973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free-running time-resolved first-pass myocardial perfusion using a multi-scale dynamics decomposition: CMR-MOTUS.","authors":"Thomas E Olausson, Maarten L Terpstra, Niek R F Huttinga, Casper Beijst, Niels Blanken, Dominika Suchá, Teresa Correia, Birgitta K Velthuis, Cornelis A T van den Berg, Alessandro Sbrizzi","doi":"10.1007/s10334-025-01291-x","DOIUrl":"10.1007/s10334-025-01291-x","url":null,"abstract":"<p><strong>Objective: </strong>First-pass myocardial perfusion involves several types of dynamics, including cardiac motion, respiratory motion, bulk motion and contrast agent inflow. To accurately quantify the initial inflow of the contrast agent, high spatiotemporal resolution MR imaging must be obtained. To achieve this, we present a novel approach, named CMR-MOTUS, for the reconstruction of time-resolved free-running first-pass myocardial perfusion by jointly estimating high-quality motion fields and contrast-varying images.</p><p><strong>Materials and methods: </strong>We propose CMR-MOTUS, which extends the MR-MOTUS framework by integrating a contrast-varying reference image with a low-rank plus sparse decomposition to capture additional dynamics such as blood flow and contrast agent inflow. This joint reconstruction framework alternates between solving for time-dependent image contrast changes and motion fields, eliminating the need for a pre-acquisition motion-static reference image. The method was tested on simulations and in-vivo datasets.</p><p><strong>Results: </strong>In simulations, CMR-MOTUS showed improved image similarity and motion field accuracy compared to state-of-the-art methods. In in-vivo tests, the methods effectively captured cardiac and respiratory motion dynamics, resulting in cine images with sharper features than state-of-the-art.</p><p><strong>Discussion: </strong>CMR-MOTUS presents significant advantages by modelling motion and contrast dynamics in the reconstruction of first-pass myocardial perfusion. The framework enables a data-efficient free-running workflow since the entire acquisition is correlated with high-quality motion fields. This approach has the potential to enhance the diagnostic value of cardiac MRI but needs further clinical validations.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"173-186"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13124790/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variable density and anisotropic field-of-view for 3D Stack-of-Stars radial imaging.","authors":"Joao Tourais, Guruprasad Krishnamoorthy, Jouke Smink, Marcel Breeuwer, Marc Kouwenhoven","doi":"10.1007/s10334-025-01283-x","DOIUrl":"10.1007/s10334-025-01283-x","url":null,"abstract":"<p><strong>Objective: </strong>To develop a non-iterative method for applying elliptical field-of-view (FOV) to radial imaging and evaluate it for Stack-Of-Stars (SOS) with variable radial density in the <math><msub><mi>k</mi> <mi>z</mi></msub> </math> direction.</p><p><strong>Materials and methods: </strong>New analytic expressions were derived to compute the radial profile angles for an elliptical FOV with and without golden angle sampling. With a major-to-minor-axis FOV ratio of 1:0.5, anisotropic FOV and variable density SOS were evaluated, using point spread function analysis, phantom imaging, and in vivo pelvic imaging.</p><p><strong>Results: </strong>Compared with conventional SOS, elliptical density in <math><msub><mi>k</mi> <mi>z</mi></msub> </math> reduced scan time by 20%, while maintaining similar levels of radial aliasing artifacts. Anisotropic FOV reduced scan time by 31%, resulting in similar levels of radial aliasing artifacts at low undersampling for objects with matching in-plane anisotropy. Combining both techniques resulted in a 45% scan time reduction. Alternatively, when compared to conventional SOS using identical scan time, variable density and anisotropic FOV both displayed a lower level of radial aliasing artifacts, although for anisotropic FOV this effect was less pronounced at higher undersampling.</p><p><strong>Discussion: </strong>Variable density and anisotropic FOV can reduce scan time and/or reduce aliasing artifacts for SOS. The new analytical expressions for elliptical FOV will facilitate future studies on anisotropic FOV radial imaging.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"217-236"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13124947/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145292635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exercise MRI stress testing of the human heart at 3 Tesla: measurement precision of biventricular function and aortic blood flow during steady-state bicycling exercise.","authors":"Hugo Klarenberg, Martijn Froeling, Tim Leiner, Hildo J Lamb, S Matthijs Boekholdt, Harald T Jørstad, Gustav J Strijkers, Adrianus J Bakermans","doi":"10.1007/s10334-025-01304-9","DOIUrl":"10.1007/s10334-025-01304-9","url":null,"abstract":"<p><strong>Objective: </strong>This work aimed to demonstrate the feasibility of quantifying heart function during bicycling exercise with dynamic real-time cine MRI at 3 Tesla, and to assess its measurement precision.</p><p><strong>Materials and methods: </strong>Twelve volunteers performed steady-state bicycling exercise, while real-time cine MR images were collected using a 72-channel receiver coil array and a parallel imaging acceleration factor of 5. Biventricular end-diastolic and end-systolic (ESV) volumes and function during exercise were compared with resting-state real-time cine MRI and conventional cardiac-gated cine MRI under breath holding, and validated against 2D phase-contrast MRI-based estimates of aortic blood flow. Precision was evaluated as the inter-session measurement repeatability.</p><p><strong>Results: </strong>Left (LV) and right ventricular (RV) stroke volumes (SV) increased progressively with exercise intensity, which was mediated by a decrease in ESV. Likewise, LV SV estimated with 2D phase-contrast MRI increased from 90 ± 17 mL at rest to 114 ± 29 mL during vigorous-intensity exercise. Repeatability coefficients were 52% and 41% for LV SV at moderate- and vigorous-intensity exercise, while RV SV repeatability coefficients were 58% and 42%, respectively.</p><p><strong>Discussion: </strong>We established an exercise MRI stress testing protocol for quantifying biventricular volumes and function during moderate- and vigorous-intensity steady-state bicycling exercise.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"187-200"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13078410/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145668943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wireless and batteryless two-dimensional opto-electro-mechanical positioner inside 3 T MRI scanner.","authors":"Senol Mutlu, Ahmet Akif Kaya, Mert Yazgan, Sabri Şirolu, Aslı Mutlu, Mahmut Beşer","doi":"10.1007/s10334-025-01303-w","DOIUrl":"10.1007/s10334-025-01303-w","url":null,"abstract":"<p><strong>Objective: </strong>To present a wireless, batteryless, and optically powered two-dimensional (2D) electro-mechanical positioner operable inside a 3 T MRI scanner.</p><p><strong>Methods: </strong>The system uses Lorentz force actuators, each comprising a coil connected to a monocrystalline silicon solar cell, leveraging the scanner's strong B₀ field. Six actuators form a rotor; two rotors are used to construct the 2D positioner using plastic, glass, and ceramic parts for MRI compatibility. The rotor is modeled using circuit-based analytical and numerical simulations, incorporating the solar cell's nonlinear current-voltage behavior. A custom coil is designed for 3 T to maximize mechanical power.</p><p><strong>Results: </strong>Experimental validation includes dynamic torque measurements inside a 53 mT home-made desktop Helmholtz coil. The clinical-grade 3 T MRI scanner experiments demonstrate successful positioning in X and Y directions via remote laser diode control and power transmission through fiber optic cables. The rotor achieves 150 rotations per minute and 3.4 mN∙m torque at 6.3 mW/mm² optical intensity, amplified to 194 mN∙m by the gear train. The positioner attains a linear velocity of 2.2 mm/s with an open-loop accuracy of 1.5 mm, verified using MR images. The system shows stable behavior without imaging artifacts during in-scanner operation.</p><p><strong>Conclusion: </strong>This is the first demonstration of a remotely controlled, optically powered 2D positioner operating wirelessly inside a clinical 3 T MRI. It enables precise marker placement or mechanical stimulation and can be extended to 5 degrees of freedom for MRI-guided interventions such as biopsies.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"331-345"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145495808","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":"Lymphoma classification with multi-parametric texture analysis of DWI and PET imaging in Hodgkin and non-Hodgkin lymphoma: a pilot study.","authors":"Archana Vadiraj Malagi, Esha Baidya Kayal, Devasenathipathy Kandasamy, Deepam Pushpam, Kedar Khare, Raju Sharma, Rakesh Kumar, Sameer Bakhshi, Amit Mehndiratta","doi":"10.1007/s10334-025-01306-7","DOIUrl":"10.1007/s10334-025-01306-7","url":null,"abstract":"<p><strong>Objective: </strong>Texture analysis in quantitative IVIM-DKI parameters was investigated for characterizing malignant and benign lymph nodes and distinguishing lymphoma subtypes, specifically Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL).</p><p><strong>Methods: </strong>A prospective cohort of twenty-one patients (n = 21) diagnosed with biopsy-proven lymphoma (HL: 13 and NHL: 8) were analyzed. All patients underwent conventional MRI including DWI with 9 b-values (0-2000s/mm²) at 1.5 T and whole-body FDG-PET/CT. IVIM-DKI parameters were estimated using IVIM-DKI model with total-variation (TV) spatial-regularization method (IDTV). Apparent diffusion coefficient (ADC) and standard uptake value (SUV) maps were also calculated. Total 31 of 3D texture features using global and second-order textures were extracted from imaging parameters in the volume-of-interest of malignant and benign lymph nodes. Machine learning linear classifier model was developed for distinguishing between malignant from benign lymph nodes and HL from NHL using textural features and area under receiver operating curve (AUROC) that were evaluated to assess diagnostic accuracy.</p><p><strong>Results: </strong>Texture parameters of neighborhood gray-tone difference matrix (NGTDM) in all IVIM-DKI parameters along with ADC demonstrated excellent diagnostic accuracy showing the highest AUROC of 0.99 (individual highest AUROC by ADC: 0.99; AUROC by all: 0.95-0.99) for distinguishing between malignant and benign lymph nodes. While gray-level co-occurrence matrix (GLCM) and gray-level run-length matrix (GLRLM) features in ADC, diffusion coefficient (D), perfusion coefficient (D*), and perfusion fraction (f) displayed the best AUROC of 0.98 (individual highest AUROC by D: 0.96; AUROC by all: 0.85-0.96) for distinguishing HL from NHL.</p><p><strong>Conclusion: </strong>Texture analysis of IVIM-DKI parameters showed promising diagnostic performance in characterizing HL and NHL. Quantitative IVIM-DKI analysis with TV may have a wide range of applicability for the clinical evaluation of lymphomas.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"289-304"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145541290","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}