Magnetic Resonance in Medicine最新文献

{"title":"Reassessment of peripheral nerve stimulation thresholds for the impulse model-optimized asymmetric head gradient coil.","authors":"David A Feinberg, Samantha J Ma, Erica Walker, Alexander J S Beckett, Dominik Rattenbacher, Elmar Rummert, Peter Dietz, Mathias Davids, Nicolas Boulant","doi":"10.1002/mrm.30523","DOIUrl":"https://doi.org/10.1002/mrm.30523","url":null,"abstract":"<p><strong>Purpose: </strong>Peripheral nerve stimulation (PNS) remains a physiologic limitation to boosting spatiotemporal resolution with more powerful gradients. We investigate discrepancies in previous measurements and model predictions from PNS experienced by volunteers scanned with the investigational \"Impulse\" gradient coil on the NexGen 7T scanner.</p><p><strong>Methods: </strong>Twenty-nine volunteers (18 males, mean ± standard deviation age 52.2 ± 17.1 years) underwent PNS characterizations in the scanner. The process was repeated after the subject positions were moved by 2 and 4 cm toward the feet, away from isocenter. These new data were compared with prior experimental data acquired at the factory (32 volunteers, 16 males, mean ± standard deviation age 58.3 ± 13.5 years) and to modeling results initially used to guide the gradient winding pattern.</p><p><strong>Results: </strong>The PNS threshold for the x-axis (left-right) was significantly below the threshold level predicted by the model used to optimize the wiring pattern and thresholds measured in the factory, whereas there was closer agreement for the y-axis (anterior-posterior) and z-axis (superior-inferior). The x-axis threshold increased as the subject was moved in the Z-direction toward the foot end of the magnet, at the expense of gradient nonlinearity distortions. Sensitivity of the threshold for the x-axis was measured as 20 mT/m per centimeter Z-offset.</p><p><strong>Conclusion: </strong>The PNS threshold of the x-axis measured in the scanner was much lower than predicted by the optimization model and as measured at the factory. Our measurements verified that PNS thresholds of asymmetric head gradient coils were sensitive to head position, subject variability, and age. The discrepancy of the PNS prediction model remains to be elucidated.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128123","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":"Cross-site harmonization of diffusion MRI data without matched training subjects.","authors":"Alberto De Luca, Tine Swartenbroekx, Harro Seelaar, John van Swieten, Suheyla Cetin Karayumak, Yogesh Rathi, Ofer Pasternak, Lize Jiskoot, Alexander Leemans","doi":"10.1002/mrm.30575","DOIUrl":"https://doi.org/10.1002/mrm.30575","url":null,"abstract":"<p><strong>Purpose: </strong>Diffusion MRI (dMRI) data typically suffer of significant cross-site variability, which prevents naively performing pooled analyses. To attenuate cross-site variability, harmonization methods such as the rotational invariant spherical harmonics (RISH) have been introduced to harmonize the dMRI data at the signal level. A common requirement of the RISH method is the availability of healthy individuals who are matched at the group level, which may not always be readily available, particularly retrospectively. In this work, we propose a framework to harmonize dMRI without matched training groups.</p><p><strong>Methods: </strong>Our framework learns harmonization features while controlling for potential covariates using a voxel-based generalized linear model (GLM). RISH-GLM allows us to simultaneously harmonize data from any number of sites while also accounting for covariates of interest, thus not requiring matched training subjects. Additionally, RISH-GLM can harmonize data from multiple sites in a single step, whereas RISH is performed for each site independently.</p><p><strong>Results: </strong>We considered data of training subjects from retrospective cohorts acquired with three different scanners and performed three harmonization experiments of increasing complexity. First, we demonstrate that RISH-GLM is equivalent to conventional RISH when trained with data of matched training subjects. Second, we demonstrate that RISH-GLM can effectively learn harmonization with two groups of highly unmatched subjects. Third, we evaluate the ability of RISH-GLM to simultaneously harmonize data from three different sites.</p><p><strong>Conclusion: </strong>RISH-GLM can learn cross-site harmonization both from matched and unmatched groups of training subjects and can effectively be used to harmonize data of multiple sites in one single step.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128121","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":"Impact of lateral movement of patients on radiofrequency-induced heating of active and passive implantable medical devices at 3T MRI.","authors":"Mir Khadiza Akter, Ao Shen, Md Zahidul Islam, Jianfeng Zheng, Michael Steckner, Ji Chen","doi":"10.1002/mrm.30578","DOIUrl":"https://doi.org/10.1002/mrm.30578","url":null,"abstract":"<p><strong>Purpose: </strong>To investigate the implications of lateral patient position on radiofrequency (RF)-induced heating of active and passive implantable medical devices (AIMDs and PIMDs) in a wide-bore 3T MRI system.</p><p><strong>Methods: </strong>In vitro simulations for two rod positions and three lateral phantom shifts were experimentally validated inside a wide-bore 3T MRI scanner. Three commercially available AIMDs (40-cm peripheral nerve stimulator [PNS], 45-cm restorative neurostimulator, and 50-cm cardiac rhythm management system) were analyzed. RF-induced heating for AIMDs was assessed using the transfer function method, which combines transfer functions with tangential electric fields along clinically relevant device pathways for the Duke, Ella, and Fats human body models. Thirty-minute temperature rises were numerically simulated near four orthopedic PIMDs (shoulder, hand-wrist plate, femoral plate, hip replacement) inside human body models.</p><p><strong>Results: </strong>RF-induced heating of the titanium rod varied with lateral phantom shifts due to changes in electric-field distribution. Centrally positioned cardiac rhythm management and restorative neurostimulator devices exhibited less than 4°C and 1°C 95th percentile temperature rise variation, respectively. Meanwhile, some PNS devices, due to their peripheral placement in regions with varying electric-field exposure, showed up to 8.8°C variation in 95th percentile temperature rise. Similarly, 1-g mass-averaged specific absorption rate near PIMDs increased by up to 50 W/Kg, and a 19.7% increase in temperature rise is noted.</p><p><strong>Conclusion: </strong>The increased flexibility in lateral patient position within wide-bore MRI can increase RF-induced heating with implications for MR conditional labeling, especially for PNS devices and PIMDs.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128122","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":"Referenceless reduction of spin-echo echo-planar imaging distortion with generative displacement mapping.","authors":"Chung-Chin Kuo, Teng-Yi Huang, Yi-Ru Lin, Tzu-Chao Chuang, Shang-Yueh Tsai, Ming-Long Wu, Hsiao-Wen Chung","doi":"10.1002/mrm.30577","DOIUrl":"https://doi.org/10.1002/mrm.30577","url":null,"abstract":"<p><strong>Purpose: </strong>We aimed to develop a fully automatic, referenceless method for correcting distortions in echo-planar imaging (EPI) data sets, specifically designed for applications in retrospective studies lacking reference field maps or reversed-gradient scans. This work primarily targets data sets acquired with anterior-posterior or posterior-anterior phase-encoding protocols.</p><p><strong>Methods: </strong>Our approach used a generative adversarial network to generate a displacement map. The network model took a three-dimensional raw b0 volume from a diffusion-tensor data set as input and reproduced a displacement map, similar to that originally derived using a reversed-gradient correction method. This generative displacement map was used to correct echo-planar images across an entire diffusion data set.</p><p><strong>Results: </strong>The performance of our method was evaluated across multiple institutions using large-scale databases. We found that it effectively reduced geometric distortions in EPI data sets and improved the accuracy of diffusion indices. Moreover, it significantly enhanced the coregistration between EPI and high-resolution T₁-weighted images (p < 0.01).</p><p><strong>Conclusions: </strong>Our referenceless EPI distortion correction method has been publicly shared as a standalone application and offers a practical solution for enhancing the quality of EPI data sets in retrospective studies. It effectively reduces distortions and increases the accuracy of diffusion measures, making it a valuable tool for studies where EPI data contain no distortion calibration scan.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128124","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":"Controlling sharpness, SNR, and specific absorption rate for 3D fast-spin echo at 7T by end-to-end learning.","authors":"Peter Dawood, Martin Blaimer, Jürgen Herrler, Patrick Liebig, Simon Weinmüller, Shaihan Malik, Peter M Jakob, Moritz Zaiss","doi":"10.1002/mrm.30533","DOIUrl":"https://doi.org/10.1002/mrm.30533","url":null,"abstract":"<p><strong>Purpose: </strong>To non-heuristically identify dedicated variable flip angle (VFA) schemes optimized for the point-spread function (PSF) and SNR of multiple tissues in 3D FSE sequences with very long echo trains at 7T.</p><p><strong>Methods: </strong>The proposed optimization considers predefined specific absorption rate (SAR) constraints and target contrast using an end-to-end learning framework. The cost function integrates components for contrast fidelity (SNR) and a penalty term to minimize image blurring (PSF) for multiple tissues. By adjusting the weights of PSF/SNR cost-function components, PSF- and SNR-optimized VFAs were derived and tested in vivo using both the open-source Pulseq standard on two volunteers as well as vendor protocols on a 7T MRI system with parallel transmit extension on three volunteers.</p><p><strong>Results: </strong>PSF-optimized VFAs resulted in significantly reduced image blurring compared to standard VFAs for T2-weighted while maintaining contrast fidelity. Small white and gray matter structures, as well as blood vessels, were more visible with PSF-optimized VFAs. Quantitative analysis shows that the optimized VFA yields 50% less deviation from a reference PSF (sinc) than the standard VFA. The SNR-optimized VFAs yielded images with significantly improved SNR in a white and gray matter region relative to standard (77.1 vs. 40.7, respectively) as trade-off for elevated image blurring.</p><p><strong>Conclusion: </strong>This study demonstrates the potential of end-to-end learning frameworks to optimize VFA schemes in very long echo trains for 3D FSE acquisition at 7T in terms of PSF and SNR. It paves the way for fast and flexible adjustment of the trade-off between PSF and SNR for 3D FSE.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128120","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":"A retraced spiral strategy with semi-automatic deblurring for volumetric thermometry.","authors":"Steven P Allen, Sheng Chen, Kang Yan, Dave A Moore, Craig H Meyer","doi":"10.1002/mrm.30560","DOIUrl":"https://doi.org/10.1002/mrm.30560","url":null,"abstract":"<p><strong>Purpose: </strong>To develop a 3D MRI-thermometry technique for transcranial MR-guided focused ultrasound (MRgFUS).</p><p><strong>Methods: </strong>A stack of retraced in-out (RIO) spirals was incorporated into a 3D, RF-spoiled, gradient recalled echo (GRE) sequence with a minimized energy deblurring strategy. Bloch simulations examined isochromat precession during RIO readout under temperature profiles matching those encountered during transcranial MRgFUS and measured the resulting effects on observed peak temperatures and FWHM of the heating patterns. The sequence then monitored temperatures in a phantom undergoing insonation from an MRgFUS device. Finally, the sequence monitored temperatures, without insonation, in four patients immediately after MRgFUS thalamotomy. For comparison, temperatures were also monitored using a frequently used, 2D, Cartesian, multi-echo, spoiled GRE sequence.</p><p><strong>Results: </strong>The RIO sequence removed under-and over-estimation of peak temperatures produced by spiral-in and spiral-out portions, respectively, of the RIO readout. In phantoms, peak temperatures from the RIO sequence were statistically indistinguishable from those from the Cartesian sequence (p > 0.05). While, in silico, the RIO sequence accurately estimated heating FWHM (error <1 mm), in phantoms, the RIO sequence overestimated FWHM (error ˜ 1 mm, p < 0.05), when compared to the Cartesian sequence. In patients, the RIO sequence had a 40% improvement in temperature efficiency compared to the Cartesian sequence, with average temperature uncertainties of 1.32 and 1.75°C, respectively. The RIO sequence also produced residual blur artifacts at tissue interfaces.</p><p><strong>Conclusions: </strong>The 3D RIO strategy with deblurring monitored focal heating under transcranial MRgFUS conditions with similar accuracy and precision as an existing 2D Cartesian method.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144111126","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":"Development and optimization of human deuterium MR spectroscopic imaging at 3 T in the abdomen.","authors":"Mary A McLean, Ines Horvat Menih, Pascal Wodtke, Joshua D Kaggie, Jonathan R Birchall, Rolf F Schulte, Ashley Grimmer, Elizabeth Latimer, Marta Wylot, Maria J Zamora Morales, Alixander S Khan, Huanjun Wang, James Armitage, Thomas J Mitchell, Grant D Stewart, Ferdia A Gallagher","doi":"10.1002/mrm.30556","DOIUrl":"https://doi.org/10.1002/mrm.30556","url":null,"abstract":"<p><strong>Purpose: </strong>To establish and optimize abdominal deuterium MR spectroscopic imaging in conjunction with orally administered ²H-labeled molecules.</p><p><strong>Methods: </strong>A flexible transmit-receive surface coil was used to image naturally abundant deuterium signal in phantoms and healthy volunteers and after orally administered ²H₂O in a patient with a benign renal tumor (oncocytoma).</p><p><strong>Results: </strong>Water and lipid peaks were fitted with high confidence from both unlocalized spectra and from voxels within the liver, kidney, and spleen on spectroscopic imaging. Artifacts were minimal, despite the high ²H₂O concentration in the stomach immediately after ingestion, which can be problematic with the use of a volume coil.</p><p><strong>Conclusion: </strong>We have shown the feasibility of abdominal deuterium MR spectroscopic imaging at 3 T using a flexible surface coil. Water measurements were obtained in healthy volunteers, and images were acquired in a patient with a renal tumor after drinking ²H₂O. The limited depth penetration of the surface coil may have advantages in characterizing early uptake of orally administered agents in abdominal organs, despite the high concentrations in the stomach which can pose challenges with other coil combinations.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144111129","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":"gammaSTAR: A framework for the development of dynamic, real-time capable MR sequences.","authors":"Simon Konstandin, Matthias Günther, Daniel C Hoinkiss","doi":"10.1002/mrm.30573","DOIUrl":"https://doi.org/10.1002/mrm.30573","url":null,"abstract":"<p><strong>Purpose: </strong>To present the real-time capability and advanced MR sequence library of the MR sequence development framework gammaSTAR.</p><p><strong>Methods: </strong>The presented platform consists of four different components: (1) a frontend for sequence development combined with a Python backend for sequence generation; (2) a Lua backend for the creation of hardware instructions; (3) a vendor-specific driver for translation of these instructions into scanner-specific objects; and (4) an interface for real-time feedback capability. In vivo measurements of the same volunteer were performed for comparison of imaging and spectroscopy sequences implemented in this framework with those of one main vendor (Siemens Healthineers) at magnetic field strengths of 3 T and 1.5 T. Prospective motion correction was integrated into a spin echo EPI sequence to demonstrate the real-time feedback capability.</p><p><strong>Results: </strong>The imaging and spectroscopy results of the gammaSTAR sequences show very similar image contrasts and qualities compared to those by the vendor. ADC maps were calculated and show values of (0.80 ± 0.14)10^-3 mm²/s in white matter. Results of pseudo-continuous spin-echo (pCASL GRASE) and 3D radial UTE imaging demonstrate the ability to run complex sequences without long sequence preparation times. Prospective motion correction is possible by means of real-time feedback and shows much fewer movement artifacts with mean voxel displacement of 1.63 mm (uncorrected) versus 0.37 mm (corrected). All images were reconstructed using the vendor's reconstruction pipeline.</p><p><strong>Conclusion: </strong>The platform gammaSTAR allows for MR sequence development with real-time feedback capability demonstrated by a large number of MR sequences and applications.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144111131","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":"Initial experience of cardiac T₁ρ mapping at 0.55 T: Continuous wave versus adiabatic spin-lock preparation pulses.","authors":"Dongyue Si, Michael G Crabb, Simon J Littlewood, Karl P Kunze, Juliet Varghese, Katherine Binzel, Mahmood Khan, Orlando P Simonetti, Claudia Prieto, René M Botnar","doi":"10.1002/mrm.30582","DOIUrl":"https://doi.org/10.1002/mrm.30582","url":null,"abstract":"<p><strong>Purpose: </strong>To propose and validate a cardiac T₁ρ mapping sequence at 0.55 T comparing continuous-wave and adiabatic spin-lock (SL) preparation pulses.</p><p><strong>Methods: </strong>The proposed 2D sequence acquires four single-shot balanced SSFP readout images with differing contrasts in a single breath-hold. The first three images are prepared with T₁ρ preparation pulses with different durations, while the last image uses a saturation pulse immediately before data acquisition. The T₁ρ map is calculated using a 3-parameter fitting method. Bloch equation simulations were performed to optimize the parameters of the adiabatic-SL pulses. Phantom studies and in vivo experiments in 10 healthy volunteers, a porcine myocardial infarction model, and a patient with suspected hypertrophic cardiomyopathy were performed to validate the performance of the proposed adiabatic T₁ρ (T₁ρ_Ad) mapping in comparison with conventional continuous-wave T₁ρ (T₁ρ_CW) mapping.</p><p><strong>Results: </strong>The adiabatic-SL pulse with simulation-optimized parameters demonstrated robust performance despite B₀ and B₁ field inhomogeneities. Phantom T₁ρ_CW and T₁ρ_Ad mapping exhibited comparable precision. In vivo experiments on healthy volunteers showed that myocardial T₁ρ_Ad is higher than T₁ρ_CW (106.1 ± 7.1 vs. 47.0 ± 5.1 ms, p < 0.01) with better precision (11.4% ± 2.6% vs. 14.5% ± 2.1%, p < 0.01) and less spatial variation (10.9% ± 3.0% vs. 14.4% ± 3.4%, p < 0.01). Both T₁ρ_CW and T₁ρ_Ad mapping agreed with late gadolinium enhancement findings in the porcine model and the patient, and exhibited improved contrast compared to T₁ and T₂ mapping.</p><p><strong>Conclusion: </strong>Both T₁ρ_CW and T₁ρ_Ad are promising for non-contrast detection of various cardiomyopathies at 0.55 T, but T₁ρ_Ad demonstrates better spatial uniformity than T₁ρ_CW.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144111135","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":"Using PINS pulses to saturate inflow effects on fMRI data at 3 and 7 T.","authors":"Shota Hodono, Chia-Yin Wu, Jin Jin, Jonathan R Polimeni, Martijn A Cloos","doi":"10.1002/mrm.30584","DOIUrl":"https://doi.org/10.1002/mrm.30584","url":null,"abstract":"<p><strong>Purpose: </strong>To suppress inflow effects by saturating the magnetization within slice gaps.</p><p><strong>Methods: </strong>Power independent of number of slices (PINS) pulses was designed to saturate the magnetization in all slice gaps at once. The PINS saturation module was played before every excitation. The saturation and excitation profiles were validated in simulation and phantom experiments. To demonstrate the efficacy of the method to suppress inflow, experiments were performed using a flow phantom. As an example use-case, fMRI experiments with and without PINS inflow saturation were performed at 3 T and 7 T.</p><p><strong>Results: </strong>Simulations and phantom experiments showed that the PINS saturation module successfully saturated the magnetization in the slice gaps without degrading the slice profile of the imaging slices. Flow phantom experiments showed that the PINS saturation module suppresses through-plane inflow better than no-gap acquisitions. In vivo fMRI experiments demonstrated that the PINS saturation module can be used to modulate the spin-echo BOLD signal. At 3 T application of PINS pulses to saturate the magnetization in the slice gaps resulted in approximately 25% fewer activated voxels (PINS-ON vs. PINS-OFF). Interestingly, at 7 T the activation patterns remained more similar and only approximately 10% fewer activated voxels were detected. The observed difference between 3 and 7 T may be linked to the relative shortening of the blood T₂.</p><p><strong>Conclusion: </strong>Using PINS pulses, inflow effects from slice gaps were effectively and efficiently saturated. The proposed PINS saturation module can be used to further study the contribution of inflow effects in fMRI data.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144111143","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}