Magnetic Resonance in Medicine最新文献

{"title":"Relaxometry and contrast-free cerebral microvascular quantification using balanced steady-state free precession MR fingerprinting.","authors":"Thomas Coudert, Aurélien Delphin, Antoine Barrier, Loïc Legris, Jan M Warnking, Laurent Lamalle, Mariya Doneva, Benjamin Lemasson, Emmanuel L Barbier, Thomas Christen","doi":"10.1002/mrm.30434","DOIUrl":"https://doi.org/10.1002/mrm.30434","url":null,"abstract":"<p><strong>Purpose: </strong>This study proposes a novel, contrast-free Magnetic Resonance Fingerprinting (MRF) method using balanced Steady-State Free Precession (bSSFP) sequences for the quantification of cerebral blood volume (CBV), vessel radius (R), and relaxometry parameters (T <math> <semantics> <mrow> <msub><mrow><mo> </mo></mrow> <mrow><mn>1</mn></mrow> </msub> </mrow> <annotation>$$ {}_1 $$</annotation></semantics> </math> , T <math> <semantics> <mrow> <msub><mrow><mo> </mo></mrow> <mrow><mn>2</mn></mrow> </msub> </mrow> <annotation>$$ {}_2 $$</annotation></semantics> </math> , T <math> <semantics> <mrow> <msub><mrow><mo> </mo></mrow> <mrow><mn>2</mn></mrow> </msub> </mrow> <annotation>$$ {}_2 $$</annotation></semantics> </math> *) in the brain.</p><p><strong>Methods: </strong>The technique leverages the sensitivity of bSSFP sequences to intra-voxel frequency distributions in both transient and steady-state regimes. A dictionary-matching process is employed, using simulations of realistic mouse microvascular networks to generate the MRF dictionary. The method is validated through in silico and in vivo experiments on six healthy subjects, comparing results with standard MRF methods and literature values.</p><p><strong>Results: </strong>The proposed method shows strong correlation and agreement with standard MRF methods for T <math> <semantics> <mrow> <msub><mrow><mo> </mo></mrow> <mrow><mn>1</mn></mrow> </msub> </mrow> <annotation>$$ {}_1 $$</annotation></semantics> </math> and T <math> <semantics> <mrow> <msub><mrow><mo> </mo></mrow> <mrow><mn>2</mn></mrow> </msub> </mrow> <annotation>$$ {}_2 $$</annotation></semantics> </math> values. High-resolution maps provide detailed visualizations of CBV and microvascular structures, highlighting differences in white matter (WM) and gray matter (GM) regions. The measured GM/WM ratio for CBV is 1.91, consistent with literature values.</p><p><strong>Conclusion: </strong>This contrast-free bSSFP-based MRF method offers an new approach for quantifying CBV, vessel radius, and relaxometry parameters. Further validation against DSC imaging and clinical studies in pathological conditions is warranted to confirm its clinical utility.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007852","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":"Three-dimensional high-isotropic-resolution MR fingerprinting optimized for 0.55 T.","authors":"Xiaozhi Cao, Congyu Liao, Zheren Zhu, Zhitao Li, Rupsa Bhattacharjee, Mark Nishmura, Zhixing Wang, Nan Wang, Zihan Zhou, Quan Chen, Daniel Abraham, Sharmila Majumdar, Javier Villanueva-Meyer, Yang Yang, Kawin Setsompop","doi":"10.1002/mrm.30420","DOIUrl":"https://doi.org/10.1002/mrm.30420","url":null,"abstract":"<p><strong>Purpose: </strong>To provide a fast quantitative imaging approach for a 0.55T scanner, where signal-to-noise ratio is limited by the field strength and k-space sampling speed is limited by a lower specification gradient system.</p><p><strong>Methods: </strong>We adapted the three-dimensional spiral projection imaging MR fingerprinting approach to 0.55T scanners, with additional features incorporated to improve the image quality of quantitative brain and musculoskeletal imaging, including (i) improved k-space sampling efficiency, (ii) Cramér-Rao lower bound optimized flip-angle pattern for specified T₁ and T₂ at 0.55 T, (iii) gradient trajectory correction, (iv) attention-based denoising, and (v) motion estimation and correction.</p><p><strong>Results: </strong>The proposed MRF acquisition and reconstruction framework can provide high-quality 1.2-mm isotropic whole-brain quantitative maps and 1-mm isotropic knee quantitative maps, each acquired in 4.5 min. The proposed method was validated in both phantom and in vivo brain and knee studies.</p><p><strong>Conclusion: </strong>By proposing novel methods and integrating advanced techniques, we achieved high-isotropic-resolution MRF on a 0.55T scanner, demonstrating enhanced efficiency, motion resilience, and quantitative accuracy.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007921","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":"In vivo GABA detection by single-pulse editing with one shot.","authors":"Li An, Sungtak Hong, Tara Turon, Adriana Pavletic, Christopher S Johnson, John A Derbyshire, Jun Shen","doi":"10.1002/mrm.30423","DOIUrl":"https://doi.org/10.1002/mrm.30423","url":null,"abstract":"<p><strong>Purpose: </strong>Two-shot γ-aminobutyric acid (GABA) difference editing techniques have been used widely to detect the GABA H4 resonance at 3.01 ppm. Here, we introduce a single-shot method for detecting the full GABA H2 resonance signal, which avoids contamination from the coedited M_3.00 macromolecules.</p><p><strong>Methods: </strong>Density matrix simulation was conducted to optimize the pulse-sequence timing, aiming to reduce the interfering glutamate H4 signal and minimize the correlation between glutamate and GABA arising from spectral overlap. The optimized sequence was used to acquire MR spectroscopy data from a 14-mL voxel in the anterior cingulate cortex of 6 healthy participants. ¹H-MRS experiments following the oral administration of [U-¹³C]glucose were also conducted.</p><p><strong>Results: </strong>The GABA H2 peak was consistently observed in all participants. The GABA/creatine ratios in the participants were determined to be 0.07 ± 0.01 with Cramer-Rao lower bounds of 8.0% ± 2.2%. Spectra acquired following [U-¹³C]glucose intake demonstrated the feasibility of using GABA H2 as a highly sensitive reporter for GABA C2.</p><p><strong>Conclusion: </strong>The proposed single-shot GABA editing method effectively minimizes interference from the glutamate H4 signal in the detection of the full GABA H2 signal, which resonates at a spectral region with much reduced macromolecule contamination.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950873","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":"Third trimester fetal 4D flow MRI with motion correction","authors":"Reagan M. Tompkins,&nbsp;Takashi Fujiwara,&nbsp;Eric M. Schrauben,&nbsp;Lorna P. Browne,&nbsp;Joost van Schuppen,&nbsp;Sally-Ann Clur,&nbsp;Richard M. Friesen,&nbsp;Erin K. Englund,&nbsp;Alex J. Barker,&nbsp;Pim van Ooij","doi":"10.1002/mrm.30411","DOIUrl":"10.1002/mrm.30411","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To correct maternal breathing and fetal bulk motion during fetal 4D flow MRI.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A Doppler-ultrasound fetal cardiac-gated free-running 4D flow acquisition was corrected post hoc for maternal respiratory and fetal bulk motion in separate automated steps, with optional manual intervention to assess and limit fetal motion artifacts. Compressed-sensing reconstruction with a data outlier rejection algorithm was adapted from previous work. Pre- and post–motion correction comparison included qualitative visibility of vasculature on phase-contrast MR angiograms (five-point Likert scale), conservation of mass of the aortic isthmus, ductus arteriosus, and descending aorta, and coefficient of variation of flow along the descending aorta.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Twenty-nine third trimester acquisitions were performed for 15 healthy fetuses and two patients with postnatally confirmed aortic coarctation during a single examination for each participant. Only 15/27 (56%) of all volunteers and 1/2 (50%) of all patient precorrection acquisitions were suitable for flow analysis. Motion correction recovered eight “failed” acquisitions, including one patient, with 24/29 (83%) suitable for flow analysis. In the 15 viable uncorrected volunteer acquisitions, motion correction improved phase-contrast MR angiograms visibility significantly in the ductus arteriosus (from 4.0 to 4.3, <i>p</i> = 0.04) and aortic arch (3.7 to 4.0, <i>p</i> = 0.03). Motion correction improved conservation of mass to a median (interquartile range) percent difference of 5% (9%) from 14% (24%) with improvement shown in 14/15 acquisitions (<i>p</i> = 0.002), whereas coefficient of variation changes were not significantly different (uncorrected: 0.15 (0.09), corrected: 0.11 (0.09), <i>p</i> = 0.3).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Motion correction compensated for maternal and fetal motion in fetal 4D flow MRI data, improving image quality and conservation of mass.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"93 5","pages":"1969-1983"},"PeriodicalIF":3.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30411","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950876","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":"Minimally invasive measurement of carotid artery and brain temperature in the mouse","authors":"Lisa M. Gazdzinski,&nbsp;Luke Chung,&nbsp;Shoshana Spring,&nbsp;Owen Botelho,&nbsp;Bojana Stefanovic,&nbsp;Brian J. Nieman,&nbsp;Chinthaka C. Heyn,&nbsp;John G. Sled","doi":"10.1002/mrm.30405","DOIUrl":"10.1002/mrm.30405","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Brain temperature is tightly regulated and reflects a balance between cerebral metabolic heat production and heat transfer between the brain, blood, and external environment. Blood temperature and flow are critical to the regulation of brain temperature. Current methods for measuring in vivo brain and blood temperature are invasive and impractical for use in small animals. This work presents a methodology to measure both brain and arterial blood temperature in anesthetized mice by MRI using a paramagnetic lanthanide complex: thulium tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (TmDOTMA^-).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A phase-based imaging approach using a multi-TE gradient echo sequence was used to measure the temperature-dependent chemical shift difference between thulium tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid methyl protons and water, and from this calculate absolute temperature using calibration data.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In a series of mice in which core body temperature was held stable but at different values within the range of 33° to 37°C, brain temperature away from the midline was independent of carotid artery blood temperature. In contrast, midline voxels correlated with carotid artery blood temperature, likely reflecting the preponderance of larger arteries and veins in this region.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>These results are consistent with brain temperature being actively regulated. A limitation of the present implementation is that the spatial resolution in the brain is coarse relative to the size of the mouse brain, and further optimization is required for this method to be applied for finer spatial scale mapping or to characterize focal pathology.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"93 5","pages":"2049-2058"},"PeriodicalIF":3.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950874","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":"Noninvasive blood–brain barrier integrity mapping in patients with high-grade glioma and metastasis by multi–echo time–encoded arterial spin labeling","authors":"Gabriel Hoffmann,&nbsp;Christine Preibisch,&nbsp;Matthias Günther,&nbsp;Amnah Mahroo,&nbsp;Matthias J. P. van Osch,&nbsp;Lena Václavů,&nbsp;Marie-Christin Metz,&nbsp;Kirsten Jung,&nbsp;Claus Zimmer,&nbsp;Benedikt Wiestler,&nbsp;Stephan Kaczmarz","doi":"10.1002/mrm.30415","DOIUrl":"10.1002/mrm.30415","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;In brain tumors, disruption of the blood–brain barrier (BBB) indicates malignancy. Clinical assessment is qualitative; quantitative evaluation is feasible using the &lt;i&gt;K&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt; leakage parameter from dynamic susceptibility contrast MRI. However, contrast agent–based techniques are limited in patients with renal dysfunction and insensitive to subtle impairments. Assessing water transport times across the BBB (&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt;) by multi-echo arterial spin labeling promises to detect BBB impairments noninvasively and potentially more sensitively.&lt;/p&gt;\u0000 \u0000 &lt;p&gt;We hypothesized that reduced &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt; indicates impaired BBB. Furthermore, we assumed higher sensitivity for &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt; than dynamic susceptibility contrast–based &lt;i&gt;K&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;, because arterial spin labeling uses water as a freely diffusible tracer.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;We acquired 3T MRI data from 28 patients with intraparenchymal brain tumors (World Health Organization Grade 3 &amp; 4 gliomas [&lt;i&gt;n&lt;/i&gt; = 17] or metastases [&lt;i&gt;n&lt;/i&gt; = 11]) and 17 age-matched healthy controls. The protocol included multi-echo and single-echo Hadamard-encoded arterial spin labeling, dynamic susceptibility contrast, and conventional clinical imaging. &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt; was calculated using a T&lt;sub&gt;2&lt;/sub&gt;-dependent multi-compartment model.&lt;/p&gt;\u0000 \u0000 &lt;p&gt;Areas of contrast-enhancing tissue, edema, and normal-appearing tissue were automatically segmented, and parameter values were compared across volumes of interest and between patients and healthy controls.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt; was significantly reduced (−20.3%) in contrast-enhancing tissue compared with normal-appearing gray matter and correlated well with |&lt;i&gt;K&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;| (&lt;i&gt;r&lt;/i&gt; = −0.347). Compared with healthy controls, &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt; was significantly lower in tumor patients' normal-appearing gray matter (&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex,tumor&lt;/sub&gt; = 0.141 ± 0.032 s vs. &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex,HC&lt;/sub&gt; = 0.172 ± 0.036 s) and normal-appearing white matter (&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex,tumor&lt;/sub&gt; = 0.116 ± 0.015 vs. &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex,HC&lt;/sub&gt; = 0.127 ± 0.017 s), whereas |&lt;i&gt;K&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;| did not differ significantly. Receiver operating characteristic analysis showed a larger area under the curve for &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt; (0.784) than &lt;i&gt;K&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt; (0.604).&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusion&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;ex&lt;/sub&gt; is sensitive to pathophysiologically impaired BBB. It a","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"93 5","pages":"2086-2098"},"PeriodicalIF":3.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30415","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950875","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":"Impact of particle size on \u0000 \u0000 \u0000 R\u0000 2\u0000 *\u0000 \u0000 and fat fraction estimation for accurate assessment of hepatic iron overload and steatosis using MRI","authors":"Utsav Shrestha,&nbsp;Sarah Brasher,&nbsp;Zachary Abramson,&nbsp;Cara E. Morin,&nbsp;Aaryani Tipirneni-Sajja","doi":"10.1002/mrm.30419","DOIUrl":"10.1002/mrm.30419","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;To investigate the impact of iron particle size on &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;*&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {R}_2^{ast } $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and fat fraction (FF) estimations for coexisting hepatic iron overload and steatosis condition using Monte Carlo simulations and phantoms.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Three iron particle sizes (0.38, 0.52, and 0.71 μm) were studied using simulations and phantoms. Virtual liver models mimicking in vivo spatial distribution of fat droplets and iron deposits were created, and MRI signals were synthesized using Monte Carlo simulations for FF 1%–30% and liver iron concentration (LIC) 1–20 mg/g. Seventy-five fat-iron phantoms with varying iron (0–8 μg/mL) and fat (0%–40%) concentrations and particle sizes were constructed. Three-way analysis of variance was used to assess the effect of iron particle size on &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;*&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {R}_2^{ast } $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and FF estimations.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;In simulations, estimated and true FF were in excellent agreement (slope: 0.93–1.09) for liver iron concentration ≤ 13 mg/g. For both simulations and phantoms, FF estimation bias increased as iron concentration increased and particle size decreased, with 0.71μm iron particle having the lowest bias (≤ 20%), and 0.52 μm and 0.38 μm iron particles producing higher bias (≥ 20%) for higher iron concentrations and lower FFs. Additionally, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;*&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {R}_2^{ast } $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; increased linearly with increasing iron concentration (&lt;i&gt;r&lt;/i&gt; ≥ 0.87) and decreasing particle size. Iron particle size significantly influenced the estimated versus true FF (simulations: &lt;i&gt;p&lt;/i&gt; = 0.04; phantoms: &lt;i&gt;p&lt;/i&gt; = 0.03) and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 ","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"93 5","pages":"2176-2185"},"PeriodicalIF":3.0,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142922044","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":"T2* relaxometry of fetal brain structures using low-field (0.55T) MRI","authors":"Kelly Payette,&nbsp;Alena U. Uus,&nbsp;Ella Kollstad,&nbsp;Jordina Aviles Verdera,&nbsp;Dario Gallo,&nbsp;Megan Hall,&nbsp;Joseph V. Hajnal,&nbsp;Mary A. Rutherford,&nbsp;Lisa Story,&nbsp;Jana Hutter","doi":"10.1002/mrm.30409","DOIUrl":"10.1002/mrm.30409","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Human brain development during gestation is complex, as both structure and function are rapidly forming. Structural imaging methods using MRI are well developed to explore these changes, but functional imaging tools are lacking. Low-field MRI is a promising modality to bridge this gap. The longer intrinsic T₂* values at low field strengths increase the dynamic range and enable the quantification of individual brain regions with low T₂* values, such as deep gray matter. This study investigates regional brain T₂* quantification throughout the second half of gestation on low-field 0.55T MRI.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Dynamic multi-echo gradient-echo sequences were acquired in 135 cases at 0.55 T between 20 and 40 weeks' gestation. Automatic high-resolution reconstruction and segmentation tools were developed, resulting in T₂* values of seven individual anatomical brain structures for each subject. These regional brain T₂* values were analyzed throughout gestation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>All regional fetal brain T₂* values decreased throughout gestation (<i>p</i> &lt; 0.01). Each anatomical brain structure had varying ranges and decay rates, with the cerebellum and white matter displaying the highest (nonfluid structure) values, with the maximum values between 350 and 400 ms at about 20 weeks. The brainstem and deep gray matter had the lowest range of T₂* values, reaching values of 250 ms early in gestation. The matched volumetric assessment of the different structures demonstrated expected growth, matching current literature.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Low-field MRI allows for a detailed, regional T₂* analysis of the fetal brain, with more inclusive norms to be developed due to its wider bore.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"93 5","pages":"1942-1953"},"PeriodicalIF":3.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30409","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142906531","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":"Detection of elevated succinate in brain during circulatory arrest in a piglet model: A 3T 1H MR spectroscopy study","authors":"Ralph E. Hurd,&nbsp;Meng Gu,&nbsp;Kenichi Okamura,&nbsp;Masafumi Shibata,&nbsp;Yoshikazu Ono,&nbsp;Moussa Haidar,&nbsp;R. Kirk Riemer,&nbsp;Frank L. Hanley,&nbsp;Daniel M. Spielman","doi":"10.1002/mrm.30414","DOIUrl":"10.1002/mrm.30414","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To measure and validate elevated succinate in brain during circulatory arrest in a piglet model of cardiopulmonary bypass.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using data from an archive of 3T ¹H MR spectra acquired in previous in-magnet studies, dynamic plots of succinate, spectral simulations and difference spectra were generated for analysis and validation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Elevation of succinate during circulatory arrest was observed and validated. Fitting bias was evaluated as a function of the line-widths and signal-to-noise ratios of the archived data. Succinate increases were independent of bypass temperature. Succinate elevation was also not observed with antegrade cerebral perfusion.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Although spectrally overlapped and at sub-millimolar levels, elevated brain succinate can be reliably measured by dynamic MR spectroscopy at 3T. Noise dependent bias of the stronger overlapping signals did not impact the succinate measurement. Elevated succinate during circulatory arrest and its recovery after reperfusion was observed. This finding is consistent with earlier reports that correlate elevated succinate with ischemic-reperfusion injury.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"93 5","pages":"1874-1885"},"PeriodicalIF":3.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142907370","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":"WALINET: A water and lipid identification convolutional neural network for nuisance signal removal in \u0000 \u0000 \u0000 \u0000  \u0000 \u0000 1\u0000 \u0000 \u0000 H\u0000 \u0000 $$ {}^1mathrm{H} $$\u0000 MR spectroscopic imaging","authors":"Paul J. Weiser,&nbsp;Georg Langs,&nbsp;Stanislav Motyka,&nbsp;Wolfgang Bogner,&nbsp;Sébastien Courvoisier,&nbsp;Malte Hoffmann,&nbsp;Antoine Klauser,&nbsp;Ovidiu C. Andronesi","doi":"10.1002/mrm.30402","DOIUrl":"10.1002/mrm.30402","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Purpose&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Proton magnetic resonance spectroscopic imaging (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mo&gt; &lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {}^1mathrm{H} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-MRSI) provides noninvasive spectral-spatial mapping of metabolism. However, long-standing problems in whole-brain &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mo&gt; &lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {}^1mathrm{H} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-MRSI are spectral overlap of metabolite peaks with large lipid signal from scalp, and overwhelming water signal that distorts spectra. Fast and effective methods are needed for high-resolution &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mo&gt; &lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {}^1mathrm{H} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-MRSI to accurately remove lipid and water signals while preserving the metabolite signal. The potential of supervised neural networks for this task remains unexplored, despite their success for other MRSI processing.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;We introduce a deep learning method based on a modified Y-NET network for water and lipid removal in whole-brain &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mo&gt; &lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {}^1mathrm{H} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-MRSI. The WALINET (WAter and LIpid neural NETwork) was compa","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"93 4","pages":"1430-1442"},"PeriodicalIF":3.0,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11782715/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142907369","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}