bluuebunny/crossref_metadata_2025 huggingface dataset:
BOLD fMRI responses to low and high frequency of sensory stimulation may reflect excitation and inhibition (im)balance
Authors: Vo Thanh , Im Geun Ho , Kim Seong-Gi
Published: November 2024

Motivation: The hyper- or hyporeactivity to sensory input is a common diagnostic criterion in autism, potentially influencing BOLD signals. Goal(s): Our study was centered on unraveling the underlying mechanisms governing the positive and negative BOLD responses to low and high sensory stimulus frequencies. A ratio of BOLD responses of high frequency to low frequency may reflect E:I balance. Approach: Our study delved into BOLD responses during varied sensory stimulation frequenciesResults: We observed increased neural activity and BOLD responses at lower frequencies, contrasting with suppressed cortical activity and subsequent negative BOLD responses at higher frequencies. Impact: A ratio of BOLD responses of high frequency to low frequency may reflect E:I balance, necessary for the clinical utility of BOLD fMRI to hyper- or hypo-reactivity responses to sensory inputs in autism
Improved diagnostic value for prostate cancer with bpMRI PI-RADS v2.1 integrating quantitative synthetic magnetic resonance imaging
Authors: Yun You , Guo Jinxia , Shao Nannan , Liu Wentao , Wang Lifeng , Zhang Xiaoxian , Shan Dongqiu , Chen Xuejun
Published: November 2024

Motivation: It’s essential to explore new imaging methods to improve the diagnostic performance of bp-MRI (T2W+DWI) PI-RADS v2.1 in the absence of DCE. Goal(s): To evaluate the potential of quantitative relaxometry from synthetic MRI in combination with bp-MRI PI-RADS v2.1 score for differentiating clinically significant prostate cancer. Approach: T2WI, T2WI fs, DWI and synthetic MRI with magnetic resonance image compilation (MAGiC) imaging in 3T MRResults: Integrating T1, T2, PD and ADC with PI-RADS score improves the diagnostic performance for lesions in peripheral zone significantly with increased both sensitivity and specificity, but not significantly for the lesions in transitional zone. Impact: The introduction of relaxometry from synthetic MRI can help improve the diagnostic efficiency in the peripheral zone when integrated with PI-RADS in the absence of DCE, which avoid the increase of peripheral zone lesions with PI-RADS score of 3.
Accelerated MR Fingerprinting with 1 mm3 spatial resolution for prostate cancer at 3.0 T
Authors: Freites Jesus Ernesto Fajardo , Yang Jiayao , Kaur Tejinder , Seiberlich Nicole , Gulani Vikas , Jiang Yun
Published: November 2024

Motivation: MRF has shown to have potential to separate cancer from non-cancer in the prostate. Improving resolution and accuracy of tissue property maps while lowering acquisition times could expedite clinical adoption of this technique. Goal(s): To obtain high-resolution 3D T1 and T2 maps in the prostate in a single rapid scan. Approach: A highly undersampled isotropic 1 mm3 SoS MRF FISP sequence with B1+ and B0 correction was developed. Results: We obtained high-resolution 3D T1 and T2 maps of the prostate from a single 6-minute scan and report these values in the normal-appearing prostate from 6 subjects and a PIRADS 5 suspected lesion. Impact: High-resolution quantitative 3D T1 and T2 maps using a single 6-minute scan may enable this technology to be used for detection and characterization of prostate lesions and encourage clinical adoption.
Association of Systemic inflammatory response index with intracranial plaque vulnerability and the severity of ischemic events
Authors: Wei Xiaofan , Zhang Wei , Cheng Jie , Zhang Limin , Xu Ruoyu , Zhang Xiaoyong
Published: November 2024

Motivation: The activation of inflammation can aggravate plaque rupture, thrombosis and cause brain tissue ischemia and infarction. Looking for reliable inflammatory markers might provide potential targets for the treatment of atherosclerosis patients. Goal(s): We investigated the relationship between systemic inflammatory response index (SIRI)and intracranial plaque features, as well as the risk factors related to the severity of cerebral ischemic events. Approach: Compare the differences in imaging features and SIRI among patients with transient ischemic attack, mild stroke, and moderate-severe stroke. Results: SIRI levels were significantly associated with plaque vulnerable characteristics and burden. Higher SIRIlevels and plaque featureswere independently related to moderate-severe stroke. Impact: Our study suggested that immune inflammation may have adverse effects on intracranial atherosclerosis, and link to the severity of cerebral ischemic events. Therefore, the regulation of immune inflammation may be a potential therapeutic target for sICAD.
Hemodynamics Contrast Investigation of Intracranial Aneurysms before and after Flow Diverter Stent Treatment
Authors: Li Xueyan , Wei Haining , Fu Mingzhu , Tian Bing , Hou Yuxi , Li Rui
Published: November 2024

Motivation: The research aims to investigate the changes in hemodynamics in intracranial aneurysms before and after treatment with blood flow shunt stents treatment. Goal(s): The technical goal is to quantify common hemodynamic parameters, and use statistical comparison to analyze the variation patterns. Approach: A set of program was utilized to separate aneurysms from complex environments, calculate hemodynamic values within the region, and analyze the trend of changes in preoperative and postoperative data. Results: The results of simple statistical analysis showed that the average flow velocity, average WSS and OSI at the aneurysm presented a decreasing trend in different degrees after the shunt stent treatment. Impact: In this study, the number of subjects and hemodynamic parameters can be increased to obtain more comprehensive experimental results. Researchers can also focus on the relationship between aneurysm stability and hemodynamics, and establish corresponding prediction and evaluation models.
GRASP-MRA: Ultra-high temporal resolution 3D-cine MRI of pulsatile aneurysmal motion at 7T
Authors: Akasaka Thai , Fujimoto Koji , Cloos Martijn , Urayama Shinichi , Okada Tomohisa
Published: November 2024

Motivation: The mortality and disability rates following cerebral aneurysm rupture remain significantly high. Recently, pulsation of aneurysms has been suggested as a novel risk factor of rupture. Goal(s): To harness the ultra-high temporal resolution and signal-to-noise ratio of the modified GRASP technique with 7T MRI to visualize pulsatile motions of cerebral aneurysms. Approach: A pulsatile aneurysm phantom and aneurysm patient were scanned using a 3D-cine MRI technique, aiming to capture dynamic aneurysmal wall movements at high spatial and ultra-high temporal resolution. Results: The new imaging technique successfully depicted pulsatile movements in the aneurysm phantom and subject, suggesting a novel predictor for aneurysm rupture. Impact: This study presents a 3D-cine MRI method at 7T, capturing aneurysm pulsations with ultra-high frame rates in the tens of milliseconds range, promising to refine rupture risk assessments and potentially reducing adverse outcomes in cerebral aneurysm management.
3D phase contrast MRI of the coronary arteries – Improvements and adaptations at 3T
Authors: Lichthardt Denise , Wetzl Jens , Schmidt Michaela , Speier Peter , Tillmanns Christoph , Nagel Armin , Giese Daniel
Published: November 2024

Motivation: 3D Phase contrast MRI of the coronary arteries remains challenging due to low SNR and motion. Goal(s): Develop a 3D PC sequence for flow quantification in the coronary arteries at 3T with improved SNR and reduced motion artefacts compared to 1.5T. Approach: The sequence was optimized by acquiring datasets separately, enabling inter-scan motion compensation while circumventing SAR limitations. Coronary flow was quantified in 5 subjects at 3T. Results: Phantom measurements showed reduced image artefacts using the proposed sequence. In-vivo mean peak velocities per slice along the left and right coronary arteries were 15.9±5.0cm/s and 14.1±4.9cm/s respectively. Impact: High SNR 3D flow measurements in the proximal coronary arteries are now possible, as SAR restrictions at 3T have been overcome. This may enable the non-invasive hemodynamic assessment of coronary arteries in patients with CAD.
Delivery of small mocluer drugs with Metal-Organic Cage-Based Microenvironment-Responsive Nanomedicine for Atherosclerosis theranostic
Authors: Li Dongye , Deng Kan , Yan Xinyu , Yang Xieqing , Zheng Cunjing
Published: November 2024

Motivation: Due to the complex pathogenesis of AS formation, the clinical treatment of AS with medicine is durable and often ineffective. it is necessary to seek a new strategy that is broadly applicable to all patients for AS theranostics . Goal(s): MM nanoparticles could delivering small molecule drugs to plaques and monitored by MR in real time upon Mn2+ released from AS microenvironment-responsive MnO2 nanoparticles. Approach: In vitro and vivo studies on 3.0T and 9.4T MR scaner. Results: In vitro and vivo studies showed that MM could be monitored by MR in real time upon Mn2+ released from acidic- and H2O2- microenvironment-responsive MnO2 nanoparticles. Impact: Nanocarriers(MM) exhibited remarkable in vivo MRI monitoring of the therapeutic process with a long imaging window and good biocompatibility and biosafety. This MRI-visible nanomedicine shows immense potential as a theranostic platform for AS therapy.
Turbo spin-echo based enhanced acceleration-selective arterial spin labeling (eAccASL) for the lower extremity MR angiography
Authors: Konta Natsuo , Shibukawa Shuhei , Horie Tomohiko , Niwa Tetsu , Obara Makoto , Okazaki Takashi , Kawamura Yui , Miyati Toshiaki
Published: November 2024

Motivation: The lower extremity MR angiography (MRA) without electrocardiography (ECG) or peripheral pulse unit (PPU) triggering and contrast enhancement is useful for diagnosing peripheral arterial disease (PAD), which can avoid synchronization failure and nephrogenic systemic fibrosis (NSF). Goal(s): Our goal was to improve peripheral arterial depiction without ECG or PPU and contrast agent. Approach: TSE-based enhanced acceleration-selective arterial spin labeling (eAccASL) (TSE-Acc) was compared with TFE-based eAccASL (TFE-Acc), and TRANCE as a reference standard by SIR, CNR, and visual inspection. Results: CNR and arterial visibility score for TSE-Acc were higher than TFE-Acc, but no difference compared with TRANCE. Impact: TSE-based enhanced acceleration-selective arterial spin labeling (eAccASL) can provide clear depiction of the peripheral arteries without ECG or PPU and contrast agent, providing sufficient diagnostic performance in PAD patients with arrhythmia and CKD.
Optimizing Pulmonary Vascular Resistances in Single Ventricle Children at Glenn Physiology using Computational Fluid Dynamics
Authors: Laudenschlager Sebastian , Schofield Samuel , Drysdale Nicolas , Stone Matthew , Romanowicz Jennifer , Frank Benjamin , DiMaria Michael , Kheyfets Vitaly , Hedjazi-Moghari Mehdi
Published: November 2024

Motivation: Individual pulmonary vascular resistances (PVR) of the left and right lung are needed to perform in-silico virtual cardiac surgery to improve Fontan conduit designs, yielding more balanced blood flow to the lungs. Goal(s): Predict patient-specific PVR of both lungs using clinical flow and pressure data acquired from cardiovascular magnetic resonance exams and catheterizations. Approach: Utilize computational fluid dynamics (CFD) and lumped parameter (LP) models to iteratively optimize the PVR of both lungs. Results: There is excellent correlation between the PVR estimates of the CFD and LP models, and both models fit to clinical outlet flow and pressure with less than 10% error. Impact: Accurate prediction of individual lung resistances is needed for patient-specific in-silico virtual cardiac surgery to optimize the design of the Fontan conduit. This design could then be implemented by surgeons to provide more balanced pulmonary blood flow in Fontan patients.
A preliminary study of accelerated mDIXON for segmented coronary adipose tissue evaluation in patients with suspected coronary artery disease
Authors: Peng Pengfei , Sun Jiayu , Zhang Xiaoyong
Published: November 2024

Motivation: We attempted to assess pericoronary adipose tissue using the mDIXON sequence of magnetic resonance imagingGoal(s): To evaluate the relationship between pericoronary adipose tissue and coronary stenosis grade and plaque typeApproach: Study design to test the hypothesisResults: Pericoronary adipose tissue volume is independently associated with the type of coronary plaqueImpact: Magnetic resonance imaging is more accurate for the assessment of adipose tissue. This is the first time to apply MRI to the assessment of pericoronary adipose tissue, and to verify its direct relationship with coronary plaque type and stenosis grade.
Quantitative evaluation of carotid atherosclerotic characteristics using in vivo carotid MR imaging with MULTIPLEX
Authors: Huo Ran , Qiao Huiyu , Chen Shuo , Han Hualu , Zhao Qiang , Xu Jiajia , Liu Ying , Zhao Xihai , Yuan Huishu
Published: November 2024

Motivation: Conventional carotid artery wall MR imaging is time-consuming due to multiple MR acquisitions. MULTIPLEX, a fast single-scan MRI technique, provides T1W/PDW/T2* maps simultaneously. Its potential in evaluating arterial plaque remains unexplored. Goal(s): Evaluating MULTIPLEX in characterising carotid plaque. Approach: We compared T1/PD/T2* values of arterial morphology and plaque components (lipid-rich necrotic core/intraplaque haemorrhage/loose matrix) in 33 participants using ANOVA between conventional technique and MULTIPLEX. Results: Significant T1/PD/T2* differences of plaque compositions mentioned above were found across all three groups with MULTIPLEX, similar to conventional technique. Varied plaque components displayed T1/PD/T2* differences. Impact: MULTIPLEX shows promises in characterising arterial plaque beyond the brain.
Real-time, multi-shot imaging improves image quality in an iCMR simulation study
Authors: Chung Nuri , Rodríguez-Soto Ana , Mahajan Niraj , Hegde Sanjeet , Schuchardt Eleanor Lehnert , Gordon Brent , Blood Joni , Potersnak Amanda , Contijoch Francisco
Published: November 2024

Motivation: Interventional cardiac MRI (iCMR) can be used to guide catheterizations, but image quality is limited by real-time imaging constraints (acquisition/reconstruction times). Goal(s): To evaluate the extent to which real-time multi-shot imaging (via adaptive radial k-space sampling, ARKS) improves iCMR image quality relative to single-shot imaging. Approach: Both ARKS and golden angle radial sampling were simulated using pediatric ECG recordings. Image quality was evaluated via mean squared error (MSE) and structural similarity index metric (SSIM). Results: ARKS increases the number of samples available for reconstruction, relative to single shot imaging with the same temporal footprint. This led to lower MSE and higher SSIM. Impact: Multi-shot real-time imaging has the potential to significantly improve interventional imaging by increasing the amount of data available for image reconstruction. In this study, we demonstrate that combining multi-shot data can improve image quality.
3D isotropic dual-phase whole-heart MRI with interleaved cardiac-triggered acquisition at 3.0T: Initial clinical experience
Authors: Zhang Shuo , Yoneyama Masami , Isaak Alexander , Katemann Christoph , Weber Oliver , Attenberger Ulrike , Luetkens Julian , Hart Christopher
Published: November 2024

Motivation: 3D dual-phase whole-heart MRI has shown advantage for simultaneous morphological and functional cardiac imaging but is so far not available at 3.0T due to bSSFP susceptibility artifacts and specific absorption rate limitation at high field. Goal(s): Our goal was to develop a new sequence to circumvent the problems and allow 3D dual-phase whole-heart MRI for high-field cardiac imaging. Approach: We implemented an interleaved cardiac-triggered acquisition with non-balanced readout and applied it in patients with congenital heart disease at 3.0T. Results: 3D dual-phase whole-heart MRI at 3.0T successfully depicted morphological and functional changes within one single scan in concordance with standard techniques. Impact: 3D isotropic dual-phase whole-heart MRI with interleaved ECG-triggered acquisition and non-balanced readout now permits visualization and assessment of cardiac morphology and function with high resolutions within one single scan at 3.0T and promises wider clinical applications in congenital heart disease.
Myocardial Pre-contrast T1 at 3T Detects Progressive Changes in Duchenne Muscular Dystrophy
Authors: Maforo Nyasha , Prosper Ashley , Renella Pierangelo , Halnon Nancy , Wu Holden , Ennis Daniel
Published: November 2024

Motivation: Duchenne muscular dystrophy (DMD) leads to pediatric cardiomyopathy. Pre-contrast T1 in DMD identifies myocardial remodeling, but it remains unclear if T1-Mapping biomarkers can detect longitudinal changes in DMD. Goal(s): The objective was to characterize progressive myocardial pre-contrast T1 changes in DMD at 3T. Approach: Boys with DMD and healthy controls underwent a 3T CMR exam that included standard functional and pre-contrast T1 mapping sequences. Boys with DMD were examined at two points (18 months apart). Results: Pre-contrast T1 was capable of detecting progressive changes in boys with DMD 18 months post baseline while functional metrics like LVEF did not. Impact: T1 Mapping biomarkers can detect disease progression in DMD. T1 Mapping biomarkers, in combination with biomarkers of function have the potential to track patient-specific changes.
Optimization of bSSFP pulse sequence parameters for low-field fetal cardiac MRI at 0.55T
Authors: Zhang Charlie , Woodgate Tomas , Verdera Jordina Aviles , Story Lisa , Hajnal Joseph , Rutherford Mary , Pushparajah Kuberan , Lloyd David , Hutter Jana , Payette Kelly
Published: November 2024

Motivation: Low field MRI at 0.55T offers advantages such as increased field homogeneities for fetal cardiac MRI and early diagnosis of congenital heart diseases (CHDs) but required careful optimization specific to the properties of low field. Goal(s): This study aimed to optimize the bSSFP sequence parameters at 0.55T to compensate for the reduced SNR and improve diagnostic capabilities in fetal cardiac MRI. Approach: Phantom experiments and in-utero studies were conducted to evaluate the impact of optimized parameters of bSSFP sequences on SNR, image quality, and clinical applicability. Results: The optimized bSSFP sequence parameters demonstrate increased SNR and good visualization of cardiac structures. Impact: The optimized bSSFP sequence at 0.55T has the potential to be used at low field strengths to prenatally diagnose congenital heart disease, thereby increasing accessibility for patients.
Novel Doppler US-gated 3D fetal whole-heart MRI with motion correction: initial validation using paired phase-contrast flow data
Authors: Woodgate Tomas , Steinweg Johannes , Franklin Rachael , Price Anthony , Roberts Thomas , Boutillon Arnaud , Uus Alena , Hutter Jana , Hajnal Jo , Deprez Maria , Pushparajah Kuberan , Lloyd David
Published: November 2024

Motivation: A novel pipeline for the creation of 3D fetal whole-heart datasets has been devised by combining Doppler US-gating and slice-to-volume registration. Goal(s): Our goal was to perform initial validation of the resultant 3D+t datasets. Approach: We assessed for internal consistency by deriving fetal stroke volume data from two methods in six subjects. Stroke volume data were obtained through volumetric analysis of the 3D+t volume alongside assessment of paired 2D+t phase-contrast flow data. Results: There was correlation between volumetrically derived stroke-volume data with that derived from 2D+t phase contrast flow, however the volumetric method was biased toward lower readings. Impact: Initial validation of a novel pipeline for the creation 3D fetal whole-heart datasets shows correlation between stroke volumes derived from volumetry and phase contrast flow data. Future work will explore the bias toward lower stroke volumes obtained by volumetry.
Using saturation bands to null signal from inflowing blood in single-slice fMRI: Toward a rapidly sampled black-blood functional contrast
Authors: Proulx Sébastien , Hodono Shota , Naradarajan Divya , Hu Zhangxuan , Cloos Martijn , Polimeni Jonathan
Published: November 2024

Motivation: Magnetization-preparation schemes using inversion recovery measure aspects of hemodynamics like perfusion and blood volume, but their temporal resolution is limited by physiology, i.e., long blood arrival/transit times. Goal(s): To study brain hemodynamics at high temporal resolutions with novel inflow saturation. Approach: We applied saturation bands on both sides of a rapidly-sampled single imaging slice to suppress inflow-related signal and produce black-blood functional contrast sensitive to macrovascular blood volume. Results: Phantom experiments show successful suppression of inflow signal with flow-velocity-dependence at low- and high-velocity regimes but independence at mid-regime. Human brain vessels exhibited partial signal suppression, with more functional suppression seen in larger vessels. Impact: Fast blood nulling may be achievable using local saturation bands contiguous to an imaging slice rather than a global inversion slab, enabling functional contrasts sensitive to macrovascular blood flow-velocity and volume suitable for studying fast hemodynamics in specific vascular compartments.
T1-weighted fMRI in mouse visual cortex at 0.1 mm resolution using a UTE sequence after iron-oxide contrast injection
Authors: Jain Naman , Bollmann Saskia , Chuang Kai-Hsiang , Polimeni Jonathan , Barth Markus
Published: November 2024

Motivation: Conventional use of typical T2* weighted sequences such as FLASH post iron-oxide contrast injection exhibits an enhanced microvascular weighting but neglects changes in pial vessels due to strong dephasing defects. Goal(s): Our goal is to study changes in the pial vessels which will hopefully aid in the interpretation of non-BOLD fMRI signals and help us understand the CBV fMRI signal at a deeper level. Approach: We utilised a radial UTE sequence post-contrast injection with short TE and short readout duration Results: We found consistent positive signal changes in the visual cortex and pial surface. Impact: We found positive signal changes at the pial surface and in the visual cortex upon stimulation. This might indicate the involvement of both micro- and macrovasculature and provide further insights into cerebral-blood-volume changes across vascular compartments.
Simultaneous high-resolution BOLD and fiber photometry of awake mice whisking shows neuromodulation response of acetylcholine
Authors: Hike David , Zhou Xiaoqing , Man Weitao , Liu Xiaochen , Jiang Yuanyuan , Lin Changrun , Tasich Ksenija , Cid Lidia Gomez , Yu Xin
Published: November 2024

Motivation: Anesthesia causes alterations in brain functional data and internal brain states affect sensory perception. Goal(s): We sought to investigate how the Blood Oxygen Level Dependence (BOLD) response from spontaneous and stimulated whisker motion in awake mice is related to cerebral arousal state monitored by acetylcholine. Approach: Mice with implanted RF coils and fiber optic cable were simultaneously imaged and acetylcholine signals were monitored to measure correlation between BOLD and acetylcholine signals. Results: We found stimulating the whiskers produced the expected contralateral BOLD response in awake animals but also an acetylcholine spike in the ipsilateral side indicating whole-brain dynamic activation occurs in awake mice. Impact: This work shows feasibility of simultaneous high-resolution EPI-based functional imaging and fiber photometry of acetylcholine response to whisker stimulation in awake mice as a multimodal method for investigating brain state from external sensory stimulation using implantable RF coils.
Submillimeter Whole-Brain VASO fMRI using a View-Sharing with Temporal Random Walk at 7 Tesla
Authors: Park Suhyung , Häkkinen Suvi , Beckett Alexander , Walker Erica , Ma Samantha , Feinberg David
Published: November 2024

Motivation: Cerebral blood volume (CBV) fMRI has inherent limitations regarding its imaging efficiency, restricting the spatial volume coverage and spatiotemporal resolutionGoal(s): To improve imaging efficiency for whole-brain VASO fMRI with high temporal resolutionApproach: we introduce a view sharing approach combined with flexible temporal encodingResults: Proposed method achieves whole-brain VASO and BOLD imaging in 8.3 seconds, while resulting in higher VASO and BOLD activations with high sensitivityImpact: We confirmed that 1) a view-sharing approach allows VASO and BOLD signal detection without contrast confounding and 2) the random encoding coupled with view sharing significantly improves the imaging efficiency by achieving an 8.3 second whole-brain VASO imaging.
7T fMRI connectivity analysis reveals decreased cerebellar motor function in MS patients
Authors: Brouwer Emma , Priovoulos Nikos , Mukerjee Renan , Strik Myrte , Wessels Mark , Strijbis Eva , Barkhof Frederik , Schoonheim Menno , van der Zwaag Wietske
Published: November 2024

Motivation: The cerebellum is a prevalent lesion site in Multiple Sclerosis but due to lack of acquisition methods its function remains understudied in MS. Goal(s): Our goal was to compare the cerebellar motor (network) function of Multiple Sclerosis patients to Healthy Controls using 7T fMRI. Approach: We employed a B1-shimmed 7T fMRI protocol and submillimetre anatomical acquisitions. This enabled us to identify cerebellar function during a motor task and identify subject specific regions of interest to analyse cerebellar motor network connectivity. Results: Our methods revealed decreased connectivity as well as lower motor task activation in Multiple Sclerosis patients compared to Healthy Controls. Impact: Our results demonstrate the use of 7T-fMRI to study cerebellar function in patients with Multiple Sclerosis. The differences found in motor and resting state activation may contribute to the overall understanding of the role of cerebellar function in Multiple Sclerosis.
Assessing motion-associated tSNR of brainstem and spinal cord fMRI in a cohort with chronic hemiparetic stroke
Authors: Hemmerling Kimberly , Reddy Neha , Dewald Julius , Bright Molly
Published: November 2024

Motivation: Motor-task fMRI is a critical modality for studying post-stroke neuronal changes in the brainstem and spinal cord, but data quality is reduced in these regions. Goal(s): We aimed to anticipate the degree of head-motion confounds before a motor-task fMRI scan and assess how this head motion affects fMRI data quality. Approach: Six post-stroke individuals performed a hand-grasp task during a head motion-capture session, then during cortical-brainstem and spinal-cord fMRI scans. Results: Head motion in the lab was positively correlated with head and spinal-cord motion during fMRI. Head and spinal-cord motion were correlated with decreased tSNR in the cortex, brainstem, and spinal cord. Impact: Head motion outside of the scanner is linked with head and spinal-cord fMRI motion and tSNR. With lab-based motion capture systems, we can anticipate motion and tSNR impacts in motor-task fMRI, useful as screening in clinical populations with increased movement.
Nonlinear kernel-based fMRI activation detection
Authors: Han Chendi , Yang Zhengshi , Zhuang Xiaowei , Cordes Dietmar
Published: November 2024

Motivation: Kernel Canonical Correlation Analysis (KCCA) is an efficient way to detect brain activation globally with less computational complexity. However, the current KCCA is limited to the linear kernel, and the performance for other more general types of kernels is not completely understood due to a lack of inverse mapping. Goal(s): This study aims to expand the current KCCA method to arbitrary nonlinear kernels. Approach: Compute correlation vector r measures the importance of each voxel’s contributing to the signal in kernel space. Results: Our results suggest that nonlinear kernels, such as the Gaussian kernel, can increase the prediction robustness under voxel shuffling. Impact: The method proposed in this abstract allows us to get the activation pattern from fMRI for any type of linear or nonlinear kernel mapping.
Sex Differences and Age-Related Decline in Absolute Cerebral Metabolic Rate of Oxygen (CMRO2) Consumption
Authors: Williams Rebecca , Cohen Alexander , Lebel R. Marc , MacDonald M. Ethan , Wang Yang , Pike G. Bruce
Published: November 2024

Motivation: Resting CMRO2 is a marker of brain health that may inform typical and pathological brain aging. However, there is conflicting literature describing how CMRO2 changes across the lifespan, which may be influenced by extraneous variables such as sex and end-tidal partial pressure of carbon dioxide (PETCO2). Goal(s): This study aimed to evaluate CMRO2 changes across the lifespan, after considering these possible confounding variables. Approach: Dual-calibrated BOLD fMRI quantified grey matter absolute CMRO2 in 83 participants. Results: Sex and age significantly predicted CMRO2. Females had higher CMRO2 than males, and CMRO2 decreased with increasing age for females. Impact: Grey matter CMRO2 decreases in normal healthy aging. Considering both sexes, the CMRO2 decline rate was -0.88 per year, after accounting for PETCO2 and sex. When males and females were analysed separately, females only showed a significant decline with age.
An Eigenmode-Based GLM Method For Task-fMRI Data Analysis
Authors: Cai Fang , Zhang Jieying , Wang Yishi , Liu Wenzhang , Hong Bo , Qian Tianyi
Published: November 2024

Motivation: In traditional fMRI experiments, the BOLD signal is influenced by the spatial distribution of veins, which is closely linked to the morphological characteristics of the cortex. Goal(s): Cortical eigenmode decomposition represents a frequency-domain approach for analyzing brain structures, yielding a set of spatial bases for dissecting large-scale brain activities. Approach: In this study, we introduced an eigenmode-based General Linear Model method to investigate the influence of spatial patterns on the activation of specific fMRI tasks. Results: The results reveal a strong correlation in spatial distribution between the reconstructed z-map and the conventional activation map. Impact: Quantitative cortical eigenmode analysis offers a frequency-domain perspective for integrating structural and functional neuroimages. Eigenmodes encode connectivity patterns within the cortical structure, offering a promising avenue for unveiling implicit connections across cortical surface through their application to brain activity analysis.
Association of blood pressure metrics with amplitudes of physiological brain pulsations
Authors: Raitamaa Lauri , Kiviniemi Vesa
Published: November 2024

Motivation: Vascular factors, like blood pressure, play a role in brain disorders, but their pathological mechanisms are still unknown. Goal(s): The study's objective was to examine the impact of blood pressure (systole/diastole) on the physiological pulsations assessed through ultrafast resting-state functional magnetic resonance imaging. Approach: We quantified brain pulsation amplitudes with the ALFF method and employed multiple linear regression to model the influence of blood pressure metrics on very low-frequency, respiratory, and cardiovascular pulsations. Results: Systolic blood pressure positively correlated with vasomotor pulsation amplitudes, while both systolic and diastolic pressures were positively correlated with cardiovascular pulsation amplitudes. Impact: Precise knowledge regarding the influence of blood pressure on brain pulsations plays a pivotal role in future developments of treatments, particularly in conditions like Alzheimer's disease, where blood pressure is a significant risk factor affecting cerebral function.
Human Resting-State Complexity of BOLD fMRI in Ultra-High-Field MRI at 7T: a primer
Authors: Grieder Matthias , Jann Kay , Denier Niklaus , Strik Werner , Soravia Leila , Jehli Elisabeth
Published: November 2024

Motivation: BOLD-fMRI intrinsic functional connectivity has limited capability to assess the temporal dynamics of complex brain networks. The insufficient signal-to-noise ratio of 3T MRI might prevent the detection of subtle alterations. Goal(s): Detecting resting-state complexity alterations in healthy subsamples using 7T MRI. Approach: Multiscale entropy was computed for ten scales from 0.1 to 1 Hz. A whole-brain ANCOVA was conducted to assess entropy differences of the scales between 30 healthy adults with spider phobia and 45 without. Results: Spider phobia showed decreased entropy in several fear-related brain regions in all scales except 1 Hz. Impact: 7T fMRI detected reduced high-frequency resting-state multiscale entropy related to spider phobia, indicating worse local processing of fear and memory-related brain regions.
Procedure for Normalization of Cerebrovascular Reactivity in Bilateral and Indeterminate Patterns of Hypoperfusion using Dynamic BOLD-CVR
Authors: Dogra Siddhant , Wang Xiuyuan , Gee James , Zhu Yihui , Ishida Koto , Dehkharghani Seena
Published: November 2024

Motivation: The BOLD response to acetazolamide offers robust estimation of cerebrovascular reactivity (CVR) with dynamic interrogation for maximal (CVRmax) augmentation. The lack of physiologic units limits use to relative CVR reductions versus normal hemispheres, confounding use for bilateral steno-occlusive disease (SOD). Goal(s): Develop normal voxel search procedure for BOLD-CVR informed by DSC perfusion in SOD. Approach: DSC in unilateral SOD patients undergoing BOLD-CVR were used to train random forest classifiers and identify voxels with CVRmax within 10% of ground-truth normal hemispheric CVRmax. Results: Median percent-differences <8% from ground-truth were achieved, indicating robust performance for extension of BOLD-CVR to bilateral SOD. Impact: We demonstrate the feasibility of a random forest classifier as a normal voxel search algorithm, in order to identify candidate voxels serving as an auto-normalization for CVR studies in settings of bilateral or indeterminate patters of steno-occlusive disease.
Estimating transcytolemmal water exchange from the Kärger model using a Bayesian method in the human brain
Authors: Ba Ruicheng , Zhu Qinfeng , Zheng Tianshu , Li Haotian , Wu Dan
Published: November 2024

Motivation: Transcytolemal water exchange time (tex) can be estimated using diffusion-time-dependent diffusion kurtosis imaging (tDKI) acquired at long diffusion times(td). However, dMRI signals acquired at long td's using STEAM sequence are noisy, fitting of tDKI model accumulates errors. Goal(s): proposed a Bayesian strategy to improve the accuracy and robustness of tex mapping based on the Kärger model (KM). Approach: we fitted the tex map based on the simulation and in vivo human brain data using Bayesian and the nonlinear least square methods to compare the fitting results. Results: Bayesian fitting significantly reduced the estimation error and variance in the simulation and in vivo scan. Impact: The proposed a Bayesian strategy significantly reduced the estimation error and variance and improved microstructural maps in vivo. And the proposed 10-minute td-dMRI protocol showed potential value for water exchange mapping in the human brain in clinical practice.
DIMOND: Universal Microstructural Model Solver for Diffusion MRI
Authors: Li Zihan , Li Ziyu , Bilgic Berkin , Lee Hong-Hsi , Ying Kui , Huang Susie , Liao Hongen , Tian Qiyuan
Published: November 2024

Motivation: Diffusion modeling is an important tool for quantifying microstructure properties from diffusion data, but its optimization is computationaly expensive. Goal(s): To achieve rapid microstructure model parameter estimation while outperforming conventional methods. Approach: DIMOND employs a neural network (NN) to map input diffusion data to model parameters and optimizes NN by minimizing the difference between the input data and the synthetic data generated via the diffusion model parametrized by NN outputs. Results: DIMOND outperforms conventional methods for fitting kurtosis and NODDI models in terms of metric accuracy. DIMOND reduces NODDI model fitting time from hours to minutes, or even seconds by leveraging transfer learning. Impact: DIMOND has a high potential to transform diffusion model fitting. Its self-supervised training paradigm, high efficacy and efficiency may dramatically improve the feasibility and accessibility of diffusion MRI based microstructure and connectivity mapping in clinical and neuroscientific applications.
Time-dependent diffusion in one-dimensional disordered media decorated by permeable membranes
Authors: Herberthson Magnus , Özarslan Evren , Basser Peter
Published: November 2024

Motivation: Characterizing water diffusion in its long-time regime is relevant to most medical applications of diffusion MRI. However, this process is challenging to model even for a one-dimensional structure with semipermeable membranes. Goal(s): Developing methods that predict the asymptotic instantaneous diffusivity from the bulk diffusivity and the membranes’ locations and permeabilities. Approach: We studied the problem theoretically and expressed the instantaneous diffusivity as an infinite sum. An independent numerical scheme is developed. Several types of disorder in the membranes’ positions were considered. Results: Our findings show excellent agreement with simulations. Our methods provide an alternative means for studying time-dependent diffusion. Impact: This report provides an improved understanding of how tissue organization and disorder may affect water diffusivity, thus making it relevant to diffusion MR studies characterizing tissue microstructure. We also provide methods for readily estimating the instantaneous diffusivity.
Time-Dependent Standard Model of diffusion in human brain white matter evaluated in vivo on the high gradient performance Connectome 2.0 scanner
Authors: Chan Kwok-Shing , Ma Yixin , Lee Hansol , Coelho Santiago , Fieremans Els , Novikov Dmitry , Huang Susie , Lee Hong-Hsi
Published: November 2024

Motivation: While most biophysical models in brain white matter estimate Gaussian compartment parameters, characteristic length scales of tissue microstructure can only be obtained from non-Gaussian features. Goal(s): To introduce time dependence into the Standard Model of diffusion; to in vivo evaluate non-Gaussian signatures of diffusion in intra- and extra-neurite spaces, irrespective of neurite orientation dispersion. Approach: We perform diffusion measurements on the Connectome 2.0 scanner in healthy volunteers at short times (13-30 ms) and estimate time-dependent diffusion parameters using GPU-accelerated fitting. Results: Time-dependent diffusion signals up to 2nd-order in spherical harmonics provide sensitivity potentially related to axonal beadings and packing correlation length. Impact: We demonstrated the feasibility of mapping time-dependent diffusion in human white matter in vivo using the Connectome 2.0 scanner. This potentially provides novel biomarkers sensitive to axon beadings and packing length scales for investigation of neurological disorders.
Cell radius and membrane permeability in the developing brain
Authors: Huynh Khoi , Ahmad Sahar , Yap Pew-Thian
Published: November 2024

Motivation: Axon and soma radii and membrane permeability are important features of brain structure and pathology but in-vivo noninvasive measurement of these biomarkers is challenging due to complex tissue architectures and inherent simplifying assumptions in MR biophysical models. Goal(s): We study membrane permeability and axon and soma radii of the developing brain during the first 5 years of life, the most dynamic and complex postnatal neurodevelopment. Approach: Different microstructure models were fitted to 389 diffusion MRI scans of 217 subjects. Measurements and developmental trends were compared with histological evidence. Results: MF-SMSI yields results that are closest to histological expectations with biologically plausible developmental trends. Impact: Noninvasive measurements of cell physical properties in the developing brain were compared with histological evidence. We present a method that yields results that are closest to histological expectations with biologically plausible developmental trends. The method can potentially facilitate neurodevelopmental studies.
The “recipe” to know the type of dynamics “before” applying the diffusion models: application in water-soluble polymer
Authors: Maiuro Alessandra , Costantini Giulio , Villani Elisa , Favero Gabriele , Taloni Alessandro , Capuani Silvia
Published: November 2024

Motivation: Currently, diffusion models are applied without knowing the type of dynamics a priori. The risk is to quantify parameters that do not reflect the dynamics of the system. Goal(s): Here we show that it is possible to carry out a preliminary check to know the type of dynamics a priori. Approach: We tested our recipe in 40% w/w Poly(ethylene glycol) (PEG) water-solution using PGSTE at different big Delta, little Delta and gradient strength. Results: We showed that both water and PEG CH2 showed a Super-Statistic dynamic while the dynamics of the OH tail of PEG is an unknown process. Impact: Currently, diffusion models are applied without knowing the type of dynamics a priori. We introduce a recipe to know the type of dynamics. This method avoids the quantification of diffusion-parameters that do not reflect the true diffusion of the system.
Linking sub-diffusion model parameters and brain cell morphometrics
Authors: Yang Qianqian , Farquhar Megan , Vegh Viktor , Palombo Marco
Published: November 2024

Motivation: The diffusion MRI signal in brain tissues can be modelled as a sub-diffusion process. The connection between sub-diffusion model parameters and microstructure of brain cells is yet to be explored. Goal(s): The research aims to investigate the link between sub-diffusion model parameters and brain cell morphometrics. Approach: Monte Carlo simulations are performed for representative brain cell types. The sub-diffusion model are then fitted to the simulated diffusion MRI data for each cell type. Results: Results reveal that the sub-diffusion model parameters are sensitive to the branch order of the cell, with higher parameter values indicating higher branch order. Impact: This is the first study to investigate how the sub-diffusion model parameters link to brain cell morphometrics. Our findings may provide new opportunities in diffusion MRI, where cell morphology and potentially cell type are of interest.
Investigating the potential of tensor-valued diffusion encoding to detect and characterise Focal Cortical Dysplasia in paediatric epilepsy
Authors: Li Yi Jie , Kerkelä Leevi , D'Arco Felice , Seunarine Kiran , Banks Tina , Szczepankiewicz Filip , Baldeweg Torsten , Clark Chris
Published: November 2024

Motivation: Radiological assessment of focal cortical dysplasia (FCD), the most common form of drug-resistant paediatric epilepsy, remains challenging on conventional MRI. Goal(s): Our goal was to test whether tensor-valued diffusion encoding, which provides metrics related to size variance and microscopic anisotropy, can be used to detect and characterise FCD. Approach: Paediatric patients were scanned with a prototype tensor-valued diffusion encoding sequence and parameter estimates were visually and statistically compared. Results: While the diffusion maps provide no strong contrast compared to structural images, our statistical results reflect FCD microstructural heterogeneity when comparing FCD and homotopic grey matter regions. Impact: Comparison of tensor-valued diffusion encoding parameters reflects FCD heterogeneity, potentially relating to lesion subtype. Despite weak contrast for FCD detection at present, this method could aid in vivo FCD characterisation in radiological assessment workflow prior to surgery.
Exploring the Potential Applications of Relaxation-Diffusion Spectrum Imaging in Neurosurgical Studies
Authors: Wu Ye , Liu Xiaoming , Sun Peng , Zhang Yizhe , Qin Jiaolong , Zhou Tao
Published: November 2024

Motivation: Relaxation-Diffusion Spectrum Imaging (RDSI) characterizes tissue apparent relaxation coefficients and factors out the effects of intra-voxel orientation heterogeneity. However, it needs to be clarified how RDSI has potential in neurosurgical research. Goal(s): We aim to investigate how RDSI can be conducive to characterizing tissue abnormalities in various neurosurgical patients. Approach: We presented two RDSI-derived indices, R2RF and RICR, to characterize tissue abnormalities. We examined the indices with an in vivo dataset, acquired using a clinical scanner, involving eight different health conditions. Results: R2RF and RICR have potential in lesion grading and treatment response evaluation. Impact: Our study promises to improve its clinical applicability and enhance our understanding of glioma biology and treatment response.
Apparent Diffusion Coefficient Measures of Metabolite in HIV: A pilot study
Authors: Joy Ajin , Saucedo Andres , Carmichael Robert , Daar Eric , Macey Paul , Emir Uzay , Thomas M. Albert
Published: November 2024

Motivation: Neurocognitive impairment in HIV and compromised neuronal integrity are characterized by varying metabolite levels. However, ADC values of metabolites have not been reported. Goal(s): To measure the metabolite ADC values at multiple locations in the brain and compare between HIV+ and healthy control groups. Approach: Use a diffusion weighted radial echo planar spectroscopic imaging technique with single-shot diffusion trace-weighted scheme to measure the metabolite ADC values. Results: Statistically significant variations were observed in Water and tCr ADCs. Further analysis of metabolite ratios showed significantly reduced tNAA and increased tCr and tCho in HIV patients compared to HC. Impact: Metabolite ADC values in HIV brain compared to HC is demonstrated using single-shot diffusion trace-weighted DW-REPSI. Statistically significant variations were observed in Water and tCr ADCs. Metabolite ratios showed significantly reduced tNAA and increased tCr and tCho in HIV patients.
Oscillating Gradient Spin Echo Shows Elevated Diffusion Dispersion Rate in Human Acute Ischemic Stroke
Authors: Zhou Mi , Stobbe Robert , Buck Brian , Kate Mahesh , Fairall Paige , Emery Derek , Feiweier Thorsten , Beaulieu Christian
Published: November 2024

Motivation: The diffusion dispersion rate (DDR, slope of diffusion with frequency of oscillating-gradient-spin-echo - OGSE) has been probed in animal stroke models and healthy human brain, but has not been explored in human acute ischemic stroke. Goal(s): Our goal is to map DDR in human stroke and explore its insight on the biophysical mechanisms related to reduced diffusion in stroke. Approach: DDR maps using OGSE 25/40/50Hz were acquired in 12 acute ischemic stroke patients. Results: DDR is significantly higher in ischemic lesions relative to contralateral white matter, and is highest in brain regions with presumably larger axons. Impact: The application of oscillating-gradient-spin-echo diffusion MRI with different oscillating frequencies highlights greater diffusion time effects in acute stroke than healthy tissue, which agrees with earlier preclinical ischemia models, and implicates changes of short range microstructural disorder (e.g. beading).