Magnetic Resonance in Medicine最新文献

{"title":"Age-specific optimization of the T₂-weighted MRI contrast in infant and toddler brain.","authors":"Jiani Wu, Fenjie Qin, Fengyu Tian, Haotian Li, Xingwang Yong, Tingting Liu, Hongxi Zhang, Dan Wu","doi":"10.1002/mrm.30339","DOIUrl":"10.1002/mrm.30339","url":null,"abstract":"<p><strong>Purpose: </strong>In 0-2-year-old brains, the T₂-weighted (T2w) contrast between white matter (WM) and gray matter (GM) is weaker compared with that in adult brains and rapidly changes with age. This study aims to design variable-flip-angle (VFA) trains in 3D fast spin-echo sequence that adapt to the dynamically changing relaxation times to improve the contrast in the T2w images of the developing brains.</p><p><strong>Methods: </strong>T₁ and T₂ relaxation times in 0-2-year-old brains were measured, and several age groups were defined according to the age-dependent pattern of T₂ values. Based on the static pseudo-steady-state theory and the extended phase graph algorithm, VFA trains were designed for each age group to maximize WM/GM contrast, constrained by the maximum specific absorption rate and overall signal intensity. The optimized VFA trains were compared with the default one used for adult brains based on the relative contrast between WM and GM. Dice coefficient was used to demonstrate the advantage of contrast-improved images as inputs for automatic tissue segmentation in infant brains.</p><p><strong>Results: </strong>The 0-2-year-old pool was divided into groups of 0-8 months, 8-12 months, and 12-24 months. The optimal VFA trains were tested in each age group in comparison with the default sequence. Quantitative analyses demonstrated improved relative contrasts in infant and toddler brains by 1.5-2.3-fold at different ages. The Dice coefficient for contrast-optimized images was improved compared with default images (p < 0.001).</p><p><strong>Conclusion: </strong>An effective strategy was proposed to improve the 3D T2w contrast in 0-2-year-old brains.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1014-1025"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142469032","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":"Layer-specific BOLD effects in gradient and spin-echo acquisitions in somatosensory cortex.","authors":"Zhangyan Yang, Mishra Arabinda, Feng Wang, Li Min Chen, John C Gore","doi":"10.1002/mrm.30326","DOIUrl":"10.1002/mrm.30326","url":null,"abstract":"<p><strong>Purpose: </strong>Previous studies have shown varied BOLD signals with gradient echo (GE) across cortical depth. To interpret these variations, and understand the effects of vascular geometry and size, the magnitudes and layer distributions of GE and spin-echo (SE) BOLD functional MRI signals were compared in the somatosensory cortex of squirrel monkeys during tactile stimulation and in a resting state at high spatial resolution and high field.</p><p><strong>Methods: </strong>A block-design stimulation was used to identify tactile-evoked activation signals in somatosensory Areas 3b and 1. Layer-specific connectivities were calculated using resting-state data. Signal power spectra were compared by depth and pulse sequence. The measured ratios of transverse relaxation rate changes were compared with Anderson and Weiss's model.</p><p><strong>Results: </strong>SE signals showed a 26% lower percentage signal change during tactile stimulation compared with GE, along with a slower time course. SE signals remained consistent but weaker in lower layers, whereas GE signals decreased with cortical depth. This pattern extended to resting-state power spectra. Resting-state functional connectivity indicated larger connectivity between the top layers of Area 3b and Area 1 for GE, with minimal changes for SE. Comparisons with theory suggest vessel diameters ranging from 19.4 to 9 microns are responsible for BOLD effects across cortical layers at 9.4 T.</p><p><strong>Conclusion: </strong>These results provide further evidence that at high field, SE BOLD signals are relatively free of contributions from sources other than microvascular changes in response to neural activity, whereas GE signals, even in the superficial layers, are not dominated by very large vessels.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1314-1328"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11680728/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142381227","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":"Single-shot echo planar time-resolved imaging for multi-echo functional MRI and distortion-free diffusion imaging.","authors":"Zijing Dong, Lawrence L Wald, Jonathan R Polimeni, Fuyixue Wang","doi":"10.1002/mrm.30327","DOIUrl":"10.1002/mrm.30327","url":null,"abstract":"<p><strong>Purpose: </strong>To develop a single-shot SNR-efficient distortion-free multi-echo imaging technique for dynamic imaging applications.</p><p><strong>Methods: </strong>Echo planar time-resolved imaging (EPTI) was first introduced as a multi-shot technique for distortion-free multi-echo imaging. This work aims to develop single-shot EPTI (ss-EPTI) to achieve improved robustness to motion/physiological noise, increased temporal resolution, and higher SNR efficiency. A new spatiotemporal encoding that enables reduced phase-encoding blips and minimized echo spacing under the single-shot regime was developed, which improves sampling efficiency and enhances spatiotemporal correlation in the k-TE space for improved reconstruction. A continuous readout with minimized deadtime was employed to optimize SNR efficiency. Moreover, k-TE partial Fourier and simultaneous multi-slice acquisition were integrated for further acceleration.</p><p><strong>Results: </strong>ss-EPTI provided distortion-free imaging with densely sampled multi-echo images at standard resolutions (e.g., ˜1.25 to 3 mm) in a single-shot. Improved SNR efficiency was observed in ss-EPTI due to improved motion/physiological-noise robustness and efficient continuous readout. Its ability to eliminate dynamic distortions-geometric changes across dynamics due to field changes induced by physiological variations or eddy currents-further improved the data's temporal stability. For multi-echo fMRI, ss-EPTI's multi-echo images recovered signal dropout in short- <math> <semantics> <mrow><msubsup><mi>T</mi> <mn>2</mn> <mo>*</mo></msubsup> </mrow> <annotation>$$ {mathrm{T}}_2^{ast } $$</annotation></semantics> </math> regions and provided TE-dependent functional information to distinguish non-BOLD noise for further tSNR improvement. For diffusion MRI, it achieved shortened TEs for improved SNR and provided images free from both B₀-induced and diffusion-encoding-dependent eddy-current-induced distortions with multi-TE diffusion metrics.</p><p><strong>Conclusion: </strong>ss-EPTI provides SNR-efficient distortion-free multi-echo imaging with comparable temporal resolutions to ss-EPI, offering a new acquisition tool for dynamic imaging.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"993-1013"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11680730/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142469066","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":"Zero-echo-time sequences in highly inhomogeneous fields.","authors":"Jose Borreguero, Fernando Galve, José M Algarín, Joseba Alonso","doi":"10.1002/mrm.30352","DOIUrl":"10.1002/mrm.30352","url":null,"abstract":"<p><strong>Purpose: </strong>Zero-echo-time (ZTE) sequences have proven a powerful tool for MRI of ultrashort <math> <semantics> <mrow> <msub><mrow><mi>T</mi></mrow> <mrow><mn>2</mn></mrow> </msub> </mrow> <annotation>$$ {T}_2 $$</annotation></semantics> </math> tissues, but they fail to produce useful images in the presence of strong field inhomogeneities (14 000 ppm). Here we seek a method to correct reconstruction artifacts from non-Cartesian acquisitions in highly inhomogeneous <math> <semantics> <mrow> <msub><mrow><mi>B</mi></mrow> <mrow><mn>0</mn></mrow> </msub> </mrow> <annotation>$$ {mathrm{B}}_0 $$</annotation></semantics> </math> , where the standard double-shot gradient-echo approach to field mapping fails.</p><p><strong>Methods: </strong>We present a technique based on magnetic field maps obtained from two geometric distortion-free point-wise (SPRITE) acquisitions. To this end, we employ three scanners with varying field homogeneities. These maps are used for model-based image reconstruction with iterative algebraic techniques (ART). For comparison, the same prior information is fed also to widely used Conjugate Phase (CP) algorithms.</p><p><strong>Results: </strong>Distortions and artifacts coming from severe <math> <semantics> <mrow> <msub><mrow><mi>B</mi></mrow> <mrow><mn>0</mn></mrow> </msub> </mrow> <annotation>$$ {mathrm{B}}_0 $$</annotation></semantics> </math> inhomogeneities, at the level of the encoding gradient, are largely reverted by our method, as opposed to CP reconstructions. This holds even close to the limit where intra-voxel bandwidths (determined by <math> <semantics> <mrow> <msub><mrow><mi>B</mi></mrow> <mrow><mn>0</mn></mrow> </msub> </mrow> <annotation>$$ {mathrm{B}}_0 $$</annotation></semantics> </math> inhomogeneities, up to 1.2 kHz) are comparable to the encoding inter-voxel bandwidth (determined by the gradient fields, 625 Hz in this work).</p><p><strong>Conclusion: </strong>We have benchmarked the performance of a new method for ZTE imaging in highly inhomogeneous magnetic fields. For example, this can be exploited for dental imaging in affordable low-field MRI systems, and can be expanded for arbitrary pulse sequences and extreme magnet geometries, as in, for example, single-sided MRI.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1190-1204"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11680741/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142469068","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":"Parallel-transmission spatial spectral pulse design with local specific absorption rate control: Demonstration for robust uniform water-selective excitation in the human brain at 7 T.","authors":"Xin Shao, Zhe Zhang, Xiaodong Ma, Fan Liu, Hua Guo, Kamil Ugurbil, Xiaoping Wu","doi":"10.1002/mrm.30346","DOIUrl":"10.1002/mrm.30346","url":null,"abstract":"<p><strong>Purpose: </strong>To propose a novel method for parallel-transmission (pTx) spatial-spectral pulse design and demonstrate its utility for robust uniform water-selective excitation (water excitation) across the entire brain.</p><p><strong>Theory and methods: </strong>Our design problem is formulated as a magnitude-least-squares minimization with joint RF and k-space optimization under explicit specific-absorption-rate constraints. For improved robustness against off-resonance effects, the spectral component of the excitation target is prescribed to have a water passband and a fat stopband. A two-step algorithm was devised to solve our design problem, with Step 1 aiming to solve a reduced problem to find a sensible start point for Step 2 to solve the original problem. The efficacy of our pulse design was evaluated in simulation, phantom, and human experiments using the commercial Nova head coil. Universal pulses were also designed based on a 10-subject training data set to demonstrate the utility of our method for plug-and-play pTx.</p><p><strong>Results: </strong>For k_T-points and spiral nonselective parameterizations, our design method outperformed the pTx interleaved binomial approach, reducing RMS error by up to about 35% for water excitation and about 97% for fat suppression (over a 200-Hz bandwidth) while decreasing local specific absorption rate by about 30%. Both our subject-specific and universal pulses improved water excitation, restoring signal loss in the cerebellum while suppressing fat signal even in regions of large susceptibility-induced off-resonances.</p><p><strong>Conclusion: </strong>Demonstrated useful for 4D (3D spatial, one-dimensional spectral) pTx spatial-spectral pulse design, our proposed method provides an effective solution for robust volumetric uniform water excitation, holding a promise to many ultrahigh-field applications.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1238-1255"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11682926/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142558189","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":"Regional variations in hyperpolarized 129Xe lung MRI: Insights from CSI-CSSR and CSSR in healthy and irradiated rat models.","authors":"Kai Ruppert, Luis Loza, Hooman Hamedani, Mostafa Ismail, Jiawei Chen, Ian F Duncan, Harrilla Profka, Stephen Kadlecek, Rahim R Rizi","doi":"10.1002/mrm.30313","DOIUrl":"10.1002/mrm.30313","url":null,"abstract":"<p><strong>Purpose: </strong>To compare pulmonary function metrics obtained with hyperpolarized xenon-129 (HXe) MRS, using chemical shift saturation recovery (CSSR) and CSI-CSSR, in healthy rats and a rat model of radiation-induced lung injury.</p><p><strong>Methods: </strong>HXe-MR data were acquired in two healthy rats and one rat with radiation-induced lung injury using whole-lung spectroscopy and CSI-CSSR techniques. The CSI-CSSR acquisitions were performed with both fixed TE and variable TE. Apparent alveolar septal wall thickness, gas transfer dynamics, and regional lung function were quantified and compared across acquisition methods. Spectral analysis included alignment of dissolved-phase frequency spectra using the membrane resonance as reference, segmentation of gas-phase (GP) frequency distribution, and characterization of gas uptake in the vasculature.</p><p><strong>Results: </strong>Complex GP line shapes were observed in rat lungs, necessitating pixel-wise CSI analysis and membrane resonance alignment for improved quantification. Notable differences in alveolar septal wall thickness, dissolved-phase GP ratios, and GP and red blood cell frequencies were found between acquisition techniques and lung conditions. CSI-CSSR provided unique insights into regional lung function, including the identification of distinct GP frequency zones potentially corresponding to different airway structures, and the ability to map relative xenon gas transport. Metrics from fixed-TE and variable-TE acquisitions usually differed by less than 10%, but the latter yielded a 20% SNR gain.</p><p><strong>Conclusion: </strong>HXe-MRS and CSI-CSSR techniques provide similar but not universally interchangeable insights into lung function, particularly in the presence of pathology.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"902-915"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11682931/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142582856","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":"Two-parametric prescan calibration of gradient-induced sampling errors for rosette MRI.","authors":"Peter Latta, Radovan Jiřík, Jiří Vitouš, Ondřej Macíček, Lubomír Vojtíšek, Ivan Rektor, Michal Standara, Jan Křístek, Zenon Starčuk","doi":"10.1002/mrm.30355","DOIUrl":"10.1002/mrm.30355","url":null,"abstract":"<p><strong>Purpose: </strong>The aim of this study was to develop a simple, robust, and easy-to-use calibration procedure for correcting misalignments in rosette MRI k-space sampling, with the objective of producing images with minimal artifacts.</p><p><strong>Methods: </strong>Quick automatic calibration scans were proposed for the beginning of the measurement to collect information on the time course of the rosette acquisition trajectory. A two-parameter model was devised to match the measured time-varying readout gradient delays and approximate the actual rosette sampling trajectory. The proposed calibration approach was implemented, and performance assessment was conducted on both phantoms and human subjects.</p><p><strong>Results: </strong>The fidelity of phantom and in vivo images exhibited significant improvement compared with uncorrected rosette data. The two-parameter calibration approach also demonstrated enhanced precision and reliability, as evidenced by quantitative <math> <semantics> <mrow><msubsup><mi>T</mi> <mn>2</mn> <mo>*</mo></msubsup> </mrow> <annotation>$$ {mathrm{T}}_2^{ast } $$</annotation></semantics> </math> relaxometry analyses.</p><p><strong>Conclusion: </strong>Adequate correction of data sampling is a crucial step in rosette MRI. The presented experimental results underscore the robustness, ease of implementation, and suitability for routine experimental use of the proposed two-parameter rosette trajectory calibration approach.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1285-1297"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11680729/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142469067","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":"Automatic segmentation and diameter measurement of deep medullary veins.","authors":"Yichen Zhou, Bingbing Zhao, Julia Moore, Xiaopeng Zong","doi":"10.1002/mrm.30341","DOIUrl":"10.1002/mrm.30341","url":null,"abstract":"<p><strong>Purpose: </strong>As one of the pathogenic factors of cerebral small vessel disease, venous collagenosis may result in the occlusion or stenosis of deep medullary veins (DMVs). Although numerous DMVs can be observed in susceptibility-weighted MRI images, their diameters are usually smaller than the MRI resolution, making it difficult to segment them and quantify their sizes. We aim to automatically segment DMVs and measure their diameters from gradient-echo images.</p><p><strong>Methods: </strong>A neural network model was trained for DMV segmentation based on the gradient-echo magnitude and phase images of 20 subjects at 7 T. The diameters of DMVs were obtained by fitting measured complex images with model images that accounted for the DMV-induced magnetic field and point spread function. A phantom study with graphite rods of different diameters was conducted to validate the proposed method. Simulation was carried out to evaluate the voxel-size dependence of measurement accuracy for a typical DMV size.</p><p><strong>Results: </strong>The automatically segmented DMV masks had Dice similarity coefficients of 0.68 ± 0.03 (voxel level) and 0.83 ± 0.04 (cluster level). The fitted graphite-rod diameters closely matched their true values. In simulation, the fitted diameters closely matched the true value when voxel size was ≤ 0.45 mm, and 92.2% of DMVs had diameters between 90 μm and 200 μm with a peak at about 120 μm, which agreed well with an earlier ex vivo report.</p><p><strong>Conclusion: </strong>The proposed methods enabled efficient and quantitative study of DMVs, which may help illuminate the role of DMVs in the etiopathogenesis of cerebral small vessel disease.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1380-1393"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11682923/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142558187","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":"Giving the prostate the boost it needs: Spiral diffusion MRI using a high-performance whole-body gradient system for high b-values at short echo times.","authors":"Malwina Molendowska, Lars Mueller, Fabrizio Fasano, Derek K Jones, Chantal M W Tax, Maria Engel","doi":"10.1002/mrm.30351","DOIUrl":"10.1002/mrm.30351","url":null,"abstract":"<p><strong>Purpose: </strong>To address key issues of low SNR and image distortions in prostate diffusion MRI (dMRI) by means of using strong gradients, single-shot spiral readouts and an expanded encoding model for image reconstruction.</p><p><strong>Methods: </strong>Diffusion-weighted spin echo imaging with EPI and spiral readouts is performed on a whole-body system equipped with strong gradients (up to 250 mT/m). An expanded encoding model including static off-resonance, coil sensitivities, and magnetic field dynamics is employed for image reconstruction. The acquisitions are performed on a phantom and in vivo (one healthy volunteer and one patient with prostate cancer). The resulting images are compared to conventional dMRI EPI with navigator-based image reconstruction and assessed in terms of their congruence, SNR, tissue contrast, and quantitative parameters.</p><p><strong>Results: </strong>Using the expanded encoding model, high-quality images of the prostate gland are obtained across all b-values (up to 3 ms/μm²), clearly outperforming the results obtained with conventional image reconstruction. Compared to EPI, spiral imaging provides an SNR gain up to 45% within the gland and even higher in the lesion. In addition, prostate dMRI with single-shot spirals at submillimeter in-plane resolution (0.85 mm) is accomplished.</p><p><strong>Conclusion: </strong>The combination of strong gradients and an expanded encoding model enables imaging of the prostate with unprecedented image quality. Replacing the commonly used EPI with spirals provides the inherent benefit of shorter echo times and superior readout efficiency and results in higher SNR, which is in particular relevant for considered applications.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1256-1272"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11680736/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142576324","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":"Low-rank iterative infilling for zero echo-time (ZTE) imaging.","authors":"Zimu Huo, José de Arcos, Florian Wiesinger, Joshua D Kaggie, Martin J Graves","doi":"10.1002/mrm.30345","DOIUrl":"10.1002/mrm.30345","url":null,"abstract":"<p><strong>Purpose: </strong>A new referenceless low-rank reconstruction technique has been introduced to address the issue of missing samples within the Zero Echo Time (ZTE) dead-time gap.</p><p><strong>Methods: </strong>The proposed method reformulates the in-filling of the missing samples as an inverse problem subject to low-rank constraints. Its performance and robustness are evaluated through a comparative analysis that combines Monte Carlo computational simulations and data obtained from in vivo experiments.</p><p><strong>Results: </strong>The proposed method is tested for dead-time gaps ranging up to 4.5 Nyquist dwells, across signal-to-noise ratio levels of 5, 10, 15, and 20 dB. Consistently superior performance is observed across all cases compared to algebraic and parallel imaging methods. The speed for convergence decreases exponentially as the dead-time gap expands.</p><p><strong>Conclusion: </strong>The proposed method enables artifact-free reconstruction up to dead-time gap of 4 Nyquist dwells and thereby supports ZTE imaging up to an imaging bandwidth of <math> <semantics><mrow><mo>±</mo> <mn>41</mn> <mo>.</mo> <mn>67</mn></mrow> <annotation>$$ pm 41.67 $$</annotation></semantics> </math> kHz (assuming transmit and receive switching less than 30 <math> <semantics><mrow><mi>μ</mi></mrow> <annotation>$$ mu $$</annotation></semantics> </math> s). It demonstrates superior performance compared to algebraic and parallel imaging methods.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":"1149-1162"},"PeriodicalIF":3.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11680738/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142576328","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}