Magnetic Resonance in Medicine最新文献

{"title":"Higher spatial resolution and sensitivity in whole brain functional MRI at 7T using 3D EPI accelerated with variable density CAIPI sampling and temporal random walk","authors":"Suhyung Park,&nbsp;Alexander Beckett,&nbsp;Suvi Häkkinen,&nbsp;Erica Walker,&nbsp;Samantha J. Ma,&nbsp;Sugil Kim,&nbsp;Hahnsung Kim,&nbsp;David A. Feinberg","doi":"10.1002/mrm.30512","DOIUrl":"10.1002/mrm.30512","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To develop an efficient 3D EPI encoding technique for high spatiotemporal resolution functional MRI.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To exploit spatiotemporal fMRI data structure, we introduce a variable density 2D CAIPI sampling in the spatial domain combined with time-wise extra random encoding in the time domain, thus achieving pseudo-regular sampling with a regular blip while allowing incoherent sampling in a complementary manner across time. This enabled temporally regularized reconstruction of highly accelerated functional data acquisition. The encoding scheme was then validated against temporally invariant CAIPI encoding by applying to locally confined and whole-brain around the primary visual cortex, respectively, with increasing the spatial resolutions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>For partial brain imaging, our proposed method achieved higher reconstruction accuracy, resulting in a substantial increase of SSIM compared to an alternative method for 0.64 mm-isotropic resolution. When used for whole brain imaging at 0.56 mm-isotropic resolution, our method showed a decreased spatial extent of activation and produced high-quality images for a clear distinction between activated and non-activated regions around calcarine fissure with high spatial specificity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The proposed 3D EPI encoding scheme, which exploits coherent and incoherent sampling properties, can significantly improve the image quality while providing a good balance between sensitivity and specificity in the activated regions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 2","pages":"678-693"},"PeriodicalIF":3.0,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30512","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144064024","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":"High-resolution and high-fidelity diffusion tensor imaging of cervical spinal cord using 3D reduced-FOV multiplexed sensitivity encoding (3D-rFOV-MUSE)","authors":"","doi":"10.1002/mrm.30558","DOIUrl":"https://doi.org/10.1002/mrm.30558","url":null,"abstract":"","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 1","pages":"C1"},"PeriodicalIF":3.0,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30558","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143871710","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":"Erratum to “First in-human evaluation of [1-13C]pyruvate in D2O for hyperpolarized MRI of the brain: A safety and feasibility study”","authors":"","doi":"10.1002/mrm.30524","DOIUrl":"10.1002/mrm.30524","url":null,"abstract":"<p>\u0000 <span>Kofi Deh, K</span>, <span>Zhang, G</span>, <span>Park, AH</span>, et al. <span>First in-human evaluation of [1-¹³C]pyruvate in D₂O for hyperpolarized MRI of the brain: a safety and feasibility study</span>. <i>Magn Reson Med</i> <span>2024</span>; <span>91</span>: <span>2559</span>–<span>2567</span>.</p><p>In the article entitled “First in-human evaluation of [1-¹³C]pyruvate in D₂O for hyperpolarized MRI of the brain: A safety and feasibility study”, the authors stated that five volunteers were imaged; however, Figures 3 and 4 show data from only four subjects. One volunteer's data was omitted from the analysis because of the premature termination of the acquisition due to a loose cable.</p><p>The inclusion of the partial data does not change the conclusion of the article. We apologize for not mentioning this in the original manuscript.</p><p>Additionally, here, we clarify study details not fully described in the original manuscript. The study was compared between two sites using the same imaging protocol for phantom tests and human studies. Ethics at site 2 was approved by the Sunnybrook Research Ethics Board and by Health Canada as a Clinical Trail Application.<span>¹</span> The coil setup at site 2 used an 8-rung low-pass birdcage for ¹³C, interchanged with an 8-channel in vivo head coil.<span>¹</span> SNR differences between two sites were because of the use of different coils, confirmed by phantom studies, which contributed to the failure to detect bicarbonate at site 1, whereas site 2 successfully detected it.<span>¹</span> T₁ estimates of the pyruvate sample were performed using a multi-nuclear spectroscopy software (GE Healthcare, NY), with a sequence using a 2D spectral-spatial excitation pulse and single-shot spiral readout.</p><p>These clarifications do not impact the conclusions of the study, and we apologize for any confusion.</p>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 2","pages":""},"PeriodicalIF":3.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30524","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144042180","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":"Contactless cardiac gating at 0.55T using high-amplitude pilot tone with interference cancellation (HAPTIC)","authors":"Bilal Tasdelen,&nbsp;Ecrin Yagiz,&nbsp;Baran R. Cinbis,&nbsp;Ye Tian,&nbsp;Krishna S. Nayak","doi":"10.1002/mrm.30528","DOIUrl":"10.1002/mrm.30528","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To enable contactless cardiac gating at 0.55T using pilot tone (PT). Current PT methods are unable to extract weak motions, including cardiac motion, at lower B₀ field strengths (&lt;1.5T).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We utilize high-amplitude pilot tone with interference cancellation, termed HAPTIC. The use of high amplitude PT improves sensitivity to cardiac motion, but introduces noise leakage into the imaging bandwidth. This leakage is removed using External Dynamic InTerference Estimation and Removal (EDITER) interference cancellation. HAPTIC performance at 0.55T is evaluated in healthy volunteers and patients with cardiac arrhythmia, over a 100-fold range in PT amplitude. Contactless HAPTIC gating performance is compared against conventional electrocardiogram (ECG). Noise enhancement due to HAPTIC is evaluated using noise-only scans acquired with varying PT amplitude levels.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We demonstrate robust extraction of cardiac PT signals at 0.55T, with cardiac gating (ECG vs. HAPTIC) jitter &lt;9 ms, and noise enhancement ˜12%–35%. We demonstrate the ability to track cardiac and respiratory phase during real-time MRI and demonstrate reliable separation of cardiac and respiratory phases for retrospective binning using HAPTIC. Furthermore, we demonstrate that HAPTIC provides accurate cardiac gating in the challenging case of arrhythmia to showcase initial feasibility.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>HAPTIC enables contactless cardiac gating at 0.55T, which has not previously been demonstrated with any PT variant. This could simplify clinical workflow and could serve as a solution for mid- and low-field MRI scanners that do not include built-in physiological monitoring.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 3","pages":"1182-1190"},"PeriodicalIF":3.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30528","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143989310","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":"In vivo 2H-MR spectroscopy and imaging of hepatic metabolic formation of trimethylamine-N-oxide","authors":"Hadar Dessau,&nbsp;Talia Harris,&nbsp;Robin A. de Graaf,&nbsp;Elton T. Montrazi,&nbsp;Hyla Allouche-Arnon,&nbsp;Amnon Bar-Shir","doi":"10.1002/mrm.30531","DOIUrl":"10.1002/mrm.30531","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>Despite growing evidence of the link between elevated levels of trimethylamine-N-oxide (TMAO) and multiple diseases, there is no method with which to spatially monitor its hepatic formation from the interstitially produced trimethylamine (TMA). This study aimed to develop a deuterium metabolic spectroscopy (DMS) and imaging (DMI) approach to detect the TMA-to-TMAO metabolism in vivo.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The metabolism of ²H₉-TMA (TMA-<i>d</i>_<i>9</i>) to ²H₉-TMAO (TMAO-<i>d</i>_<i>9</i>) in cells overexpressing the hepatic enzyme flavin-dependent monooxygenase 3 (FMO3) was monitored in vitro with ²H-NMR. Using an ultrahigh-field (15.2T) MRI scanner, the hepatic metabolism of the orally administered TMA-<i>d</i>_<i>9</i> to TMAO-<i>d</i>_<i>9</i> was studied in mice with DMS and DMI.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The spectrally resolved ²H-NMR peaks of intracellularly produced TMAO-<i>d</i>_<i>9</i> (3.1 ppm) from that of supplemental TMA-<i>d</i>_<i>9</i> (2.7 ppm) could be detected only in cells that overexpressed FMO3. In vivo, DMS and DMI experiments performed after oral administration of TMA-<i>d</i>_<i>9</i> revealed the conversion to high TMAO-<i>d</i>_<i>9</i> levels in the liver of females, which express high levels of FMO3. In contrast, there was no indication of TMAO-<i>d</i>_<i>9</i> production in the liver of males, in agreement with reports of the role of testosterone in downregulating the expression of FMO3.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>This work shows the ability to use ²H-MR-based methodologies to spatially monitor the TMA-to-TMAO metabolic pathway in vivo, and thus should be explored further to investigate the role of TMAO in diverse pathologies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 2","pages":"521-529"},"PeriodicalIF":3.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30531","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143969948","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":"Saturation transfer MR fingerprinting for magnetization transfer contrast and chemical exchange saturation transfer quantification","authors":"Munendra Singh,&nbsp;Beomgu Kang,&nbsp;Sultan Z. Mahmud,&nbsp;Peter van Zijl,&nbsp;Jinyuan Zhou,&nbsp;Hye-Young Heo","doi":"10.1002/mrm.30532","DOIUrl":"10.1002/mrm.30532","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>The aim of this study was to develop a saturation transfer MR fingerprinting (ST-MRF) technique using a biophysics model-driven deep learning approach.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A deep learning–based quantitative saturation transfer framework was proposed to estimate water, magnetization transfer contrast, and amide proton transfer (APT) parameters plus B₀ field inhomogeneity. This framework incorporated a Bloch-McConnell simulator during neural network training and enforced consistency between synthesized MRF signals and experimentally acquired ST-MRF signals. Ground-truth numerical phantoms were used to assess the accuracy of estimated tissue parameters, and in vivo tissue parameters were validated using synthetic MRI analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The proposed ST-MRF reconstruction network achieved a normalized root mean square error (nRMSE) of 9.3% when tested against numerical phantoms with a signal-to-noise ratio of 46 dB, which outperformed conventional Bloch-McConnell fitting (nRMSE of 15.3%) and dictionary-matching approaches (nRMSE of 19.5%). Synthetic MRI analysis indicated excellent similarity (RMSE = 3.2%) between acquired and synthesized ST-MRF images, demonstrating high in vivo reconstruction accuracy. In healthy human brains, the APT pool size ratios for gray and white matter were 0.16 ± 0.02% and 0.13 ± 0.02%, respectively, and the exchange rates for gray and white matter were 101 ± 25 Hz and 131 ± 27 Hz, respectively. The reconstruction network processed the eight tissue parameter maps in approximately 27 s for ST-MRF data sized at 256 × 256 × 9 × 103.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>This study highlights the feasibility of the deep learning–based ST-MRF imaging for rapid and accurate quantification of free bulk water, magnetization transfer contrast, APT parameters, and B₀ field inhomogeneity.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 3","pages":"993-1009"},"PeriodicalIF":3.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30532","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144007492","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":"Age dependency of neurometabolite T1 relaxation times","authors":"Saipavitra Murali-Manohar,&nbsp;Helge J. Zöllner,&nbsp;Kathleen E. Hupfeld,&nbsp;Yulu Song,&nbsp;Emily E. Carter,&nbsp;Vivek Yedavalli,&nbsp;Steve C. N. Hui,&nbsp;Dunja Simicic,&nbsp;Aaron T. Gudmundson,&nbsp;Gizeaddis Lamesgin Simegn,&nbsp;Christopher W. Davies-Jenkins,&nbsp;Georg Oeltzschner,&nbsp;Eric C. Porges,&nbsp;Richard A. E. Edden","doi":"10.1002/mrm.30507","DOIUrl":"10.1002/mrm.30507","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To measure T₁ relaxation times of metabolites at 3 T in a healthy aging population and investigate age dependence.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A cohort of 101 healthy adults was recruited with approximately 10 male and 10 female participants in each “decade” band: 18 to 29, 30 to 39, 40 to 49, 50 to 59, and 60+ years old. Inversion-recovery PRESS data (TE/TR: 30/2000 ms) were acquired at 8 inversion times (TIs) (300, 400, 511, 637, 780, 947, 1148, and 1400 ms) from voxels in white-matter-rich centrum semiovale (CSO) and gray-matter-rich posterior cingulate cortex (PCC). Modeling of TI-series spectra was performed in Osprey 2.5.0. Quantified metabolite amplitudes for total <i>N</i>-acetylaspartate (tNAA_2.0), total creatine at 3.0 ppm (tCr_3.0), and 3.9 ppm (tCr_3.9), total choline (tCho), myo-inositol (mI), and the sum of glutamine and glutamate (Glx) were modeled to calculate T₁ relaxation times of metabolites.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>T₁ relaxation times of tNAA_2.0 in CSO and tNAA_2.0, tCr_3.0, mI, and Glx in PCC decreased with age. These correlations remained significant when controlling for cortical atrophy. T₁ relaxation times were significantly different between PCC and CSO for all metabolites except tCr_3.0. We also propose linear models for predicting metabolite T₁s at 3 T to be used in future aging studies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Metabolite T₁ relaxation times change significantly with age, an effect that will be important to consider for accurate quantitative MRS, particularly in studies of aging.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 2","pages":"508-520"},"PeriodicalIF":3.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144017430","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":"When CEST meets diffusion: Multi-echo diffusion-encoded CEST (dCEST) MRI to measure intracellular and extracellular CEST signal distributions","authors":"Sultan Z. Mahmud,&nbsp;Hye-Young Heo","doi":"10.1002/mrm.30530","DOIUrl":"10.1002/mrm.30530","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To develop a multi-echo, diffusion-encoded chemical exchange saturation transfer (dCEST) imaging technique for estimating the intracellular and extracellular/intravascular contributions to the conventional CEST signal.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A dCEST pulse sequence was developed to quantify the signal fractions, transverse relaxation times (T₂), and apparent diffusion coefficient (ADC) of the intracellular and extracellular/intravascular water compartments. dCEST images were acquired across a wide range of TE, b-values, RF saturation strengths, and frequency offsets. The data were analyzed using a two-compartment model with distinct diffusivities and T₂ values. Intracellular and extracellular fractions of conventional water-saturation spectra (Z-spectra) and corresponding amide proton transfer (APT) signals were estimated from human brain scans of healthy volunteers at 3 T.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The multi-echo diffusion results showed that the intracellular water fractions were significantly higher than the extracellular water fractions, whereas the intracellular T₂ values were shorter than those of the extracellular/intravascular compartments. The ADC for the intracellular compartment was significantly lower than that of the extracellular compartment. The dCEST analysis showed that the average intracellular and extracellular fractions of the Z-spectra were 85 ± 7% and 15 ± 4%, respectively. The overall intracellular APT-weighted values were higher than the total (i.e., intracellular + extracellular) APT-weighted values.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The dCEST imaging technique provides valuable insight into the source of signals in conventional CEST MRI, offering potential utility for clinical applications.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 3","pages":"982-992"},"PeriodicalIF":3.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30530","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144064135","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":"MR-Cavitation Dynamics Encoded (MR-CaDE) imaging","authors":"Dinank Gupta,&nbsp;Tarana P. Kaovasia,&nbsp;Steven P. Allen,&nbsp;Jon-Fredrik Nielsen,&nbsp;Timothy L. Hall,&nbsp;Zhen Xu,&nbsp;Douglas C. Noll","doi":"10.1002/mrm.30517","DOIUrl":"10.1002/mrm.30517","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 develop methods for dynamic cavitation monitoring of a non-invasive ultrasound mechanical ablation technology (histotripsy) in the brain and test its feasibility for treatment monitoring in &lt;i&gt;ex-vivo&lt;/i&gt; brain in a human MRI scanner.&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;A Gradient Echo (GRE) pulse sequence was modified with a bipolar gradient to perform MR-Cavitation Dynamics Encoded (MR-CaDE) imaging. Cavitation generated by histotripsy sonication was monitored using MR-CaDE imaging in &lt;i&gt;ex-vivo&lt;/i&gt; bovine brain tissues on a &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;3&lt;/mn&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ 3mathrm{T} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; human MRI scanner. Bipolar gradients with a b-value of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mtext&gt;b&lt;/mtext&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;50&lt;/mn&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mo&gt;/&lt;/mo&gt;\u0000 &lt;msup&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mtext&gt;mm&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ mathrm{b}=50mathrm{s}/{mathrm{mm}}^2 $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and smaller were used while a trigger was sent from the MR scanner to the histotripsy driving electronics. MR acquisition was performed with TE/TR: &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;19&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mtext&gt;ms&lt;/mtext&gt;\u0000 &lt;mo&gt;/&lt;/mo&gt;\u0000 &lt;mn&gt;100&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mtext&gt;ms&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ 19kern.2em mathrm{ms}/100kern.2em mathrm{ms} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; with 1.5-cycle histotripsy sonications at 1 pulse/TR. Feasibility of treatment monitoring was also evaluated for histotripsy through an excised human skull.&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;The MR-CaDE imaging pulse sequence was used to perform treatment monitoring of cavitation generated ","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 2","pages":"665-677"},"PeriodicalIF":3.0,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30517","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143803425","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":"Cerebrovascular reactivity differences in healthy cerebral gray and white matter","authors":"Harrison T. Levine,&nbsp;Julien Poublanc,&nbsp;Ece Su Sayin,&nbsp;James Duffin,&nbsp;Olivia Sobczyk,&nbsp;Joseph A. Fisher,&nbsp;David J. Mikulis","doi":"10.1002/mrm.30481","DOIUrl":"10.1002/mrm.30481","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>To quantify the speed and magnitude of cerebrovascular reactivity (CVR) metrics in hemispheric gray and white matter.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A standardized isoxic hypercapnic cerebrovascular stimulus was administered using an automated arterial gas targeting system while monitoring blood oxygen–level dependent MRI. The correlation between the blood oxygen–level dependent signal and end-tidal partial pressure of carbon dioxide were measured over time, enabling calculation of CVR metrics including the magnitude and speed (TAU) of the vascular response. The average CVR magnitude and TAU metrics were obtained from 50 healthy participants in the following regions: anterior, middle, and posterior cerebral artery (ACA, MCA, PCA) territory gray matter, the striatum, the thalamus, and hemispheric white matter.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The average MCA CVR is 17.39% greater than ACA CVR (95% confidence interval [CI]: 3.50, 31.28), and the average PCA CVR is 43.03% (95% CI: 29.13, 56.91) and 21.84% (95% CI: 10.00, 33.68) greater than ACA CVR and MCA CVR, respectively. The average TAU in the six regions were ACA = 29.5 ± 9.7 s, MCA = 29.4 ± 8.7 s, PCA = 28.6 ± 10.2 s, striatum = 30.5 ± 8.9 s, thalamus = 25.7 ± 10.0 s, and white matter = 46.3 ± 6.9 s. TAU was similar among all regions investigated except for the white matter, which was approximately 60% slower than the other regions (<i>p</i> &lt; 0.0001).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>In healthy individuals, there are significant differences in CVR metrics among the ACA, MCA, PCA gray-matter vascular territories, thalamus, striatum, and hemispheric white matter. Future investigations of CVR should consider the presence of regional variability in CVR metrics when comparing healthy and diseased populations.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18065,"journal":{"name":"Magnetic Resonance in Medicine","volume":"94 2","pages":"745-753"},"PeriodicalIF":3.0,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrm.30481","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143795811","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}