bluuebunny/crossref_metadata_2025 huggingface dataset:
MULti-TImepoint VElocity-selective Reconciled with Spatially-sElective (MULTIVERSE) ASL: Pushing the Limit of Arterial Transit Time
Authors: Xu Feng , Liu Dapeng , Zhu Dan , Soldan Anja , Albert Marilyn , Lindquist Martin , Lin Doris , Qin Qin
Published: November 2024

Motivation: Existing multi-timepoint arterial spin labeling (ASL) methods can only estimate cerebral blood flow (CBF) and arterial transit time (ATT) with a limited range of ATT (<2000ms). Goal(s): Improve quantification of CBF and ATT for a wide range of ATT. Approach: MULTIVERSE ASL applies combined fitting of multi-PLD pseudo-continuous (PC) ASL and multi-PLD velocity-selective (VS) ASL to measure CBF and ATT. Results: With the same scan time, MULTIVERSE ASL improved the accuracy and precision and reduced uncertainty in CBF and ATT quantification across an extended range of ATT (500-4000ms). Impact: This novel and straightforward approach improves perfusion measurement over the extended range of arterial transit time which was not possible with existing ASL methods. It highlights the clinical potential of ASL-based perfusion mapping in various altered physiological and pathological conditions.
Quantifying microscopic anisotropy in the human heart in vivo using ultra-strong gradients
Authors: Afzali Maryam , Mueller Lars , Coveney Sam , Jones Sarah , Evans John , Fasano Fabrizio , Dall'Armellina Erica , Szczepankiewicz Filip , Teh Irvin , Jones Derek , Schneider Jürgen
Published: November 2024

Motivation: Tensor-valued diffusion encoding has been shown to provide more information on tissue microstructure than conventional diffusion weighting/tensor imaging. Goal(s): Quantifying microscopic anisotropy, isotropic and anisotropic kurtosis in a human heart in vivo with a TE commonly used for DTI. Approach: We used strong gradients ($$$\mathrm{G_{max}=300\,mT/m}$$$) in combination with linear, planar, and spherical tensor encoding with up to second-order motion compensation to achieve $$$\mathrm{b_{max} = 1500\,s/mm^2}$$$ with a TE of 74 ms. Results: Estimated diffusion metrics matched the values reported in the literature while a shorter echo time was achieved due to the strong gradients used resulting in increased SNR and therefore image quality. Impact: We implemented tensor-valued diffusion encoding with ultra-strong gradients for in vivo cardiac diffusion MRI in humans. This allows us to quantify microscopic anisotropy and kurtosis.
Enabling high SNR cardiac spin echo DTI with a Cima.X MR System featuring 200 mT/m maximum gradient strength
Authors: Kara Danielle , Liu Yuchi , Chen Shi , Garrett Thomas , Bi Xiaoming , Kwon Deborah , Nguyen Christopher
Published: November 2024

Motivation: SNR and parameter map accuracy in cardiac DTI are limited by maximum gradient strength related to motion-compensation and diffusion encoding time, precluding evaluation of helical cardiomyocyte structure. Goal(s): Our goal was to improve SNR and cardiac DTI tissue microstructure characterization using an MR system capable of 200mT/m maximum gradient strength. Approach: DTI was performed in human and swine subjects using standard (40mT/m), performance (80mT/m), and ultra-high-performance (200mT/m) maximum gradient strengths, with zeroth, first, and second-order motion compensating gradients. Results: SNR and DTI tissue characterization were improved with ultra-high-performance gradients, however second-order motion compensation continued to be required to prevent motion artifacts. Impact: Ultra-high performance 200mT/m gradients enable high SNR cardiac DTI with improved characterization of helical cardiomyocytes, potentially addressing the clinical need for noninvasive cardiac microstructure evaluation.
Axonal Diameter Mapping as a biomarker for mTBI as detected by ultrahigh-bvalue DWI in a high performance Head-only gradient system, MAGNUS.
Authors: Morris H. Douglas , Abad Nastaren , Bhushan Chitresh , Marinelli Luca , Kohls Gail , Hood Maureen , DeMarco James , Shih Robert , Ho Vincent , Foo Thomas
Published: November 2024

Motivation: Detect a mild traumatic brain injury with a reliable diagnostic for staging disease state and the testing therapies for treating the malady in acute and long term phase. Goal(s): Develop a MRI biomarker that can be repeated used on patients especially in the warfighter population which have more that 500,000 diagnosed mTBI over the past 30 year. Approach: Use of diffusion MRI to determine the white matter microstructural state namely the axon diameter. Results: MAGNUS SE-DWI high-B can detect changes in axon diameter and follow these changes in single subject over time. Impact: High B-value diffusion imaging (b > 30000 mm2/sec) can detect changes in mild TBI subjects that can be seen to progress through the recovery process. The high-performance gradient system, MAGNUS, (200mT/m, 500T/m/s) scanning without peripheral nerve stimulation in the subject.
Diffusion Tensor Imaging at 0.05 T
Authors: Ding Ye , Xiao Linfang , Su Shi , Hu Jiahao , Zhao Yujiao , Wu Ed
Published: November 2024

Motivation: The employment of DTI in ULF MRI systems demonstrates considerable potential for examining microstructural variations in neuropathology and therapy. Although confronted with the inherent obstacle of low SNR at ULF, incorporating DTI yields an array of benefits. These advantages involve heightened accessibility, diminished costs, and superior patient care, while simultaneously extending the range of application possibilities for this crucial imaging modality throughout diverse healthcare contexts. Goal(s): The implementation of DTI on an ULF MRI scanner. Approach: DTI protocol was successfully implemented at 0.05 T. Results: This study demonstrated the successful implementation of DTI protocol on an ULF MRI system. Impact: This study explored the potential of a 0.05 T MRI system to increase MRI accessibility. Successful DTI implementation demonstrated the scanner's capacity to examine microstructural changes, highlighting its promising application in this field.
Evaluation of Magnetic Resonance Mediated Radiofrequency Ablation in Bovine Liver Tissue Using Textile Antenna-Enhanced MR Thermometry.
Authors: Ullah Sana , Oh Sukhoon , Yoo Hyoungsuk
Published: November 2024

Motivation: Magnetic resonance-mediated radiofrequency ablation (MR-RFA) combines diagnostic and therapeutic functions within MRI scanners, and its significance has grown rapidly, particularly in tumor treatment diagnosis. Goal(s): In this study, a 3T Philips MRI scanner is channeled toward the ablation site in the bovine liver by means of an antenna and a needle, with the objective of generating RF heating at the tumor location. Approach: MR thermometry was used to evaluate the MR-RFA procedure and predict local specific absorption rate (SAR) escalation and temperature increase. Results: Our research demonstrated that temperature maps with a 73 oC peak value were observed at the needle tip. Impact: In contrast to existing ablation designs, this design provides enhanced patient comfort, localized heating, minimal skin burns, and avoids the use of external RF power sources, all while ensuring there is no distortion in MR images.
First Evidence of sustained reduction of Essential Tremor with MR-Guided Low-Energy Ultrasound Neuromodulation
Authors: Pyatigorskaya Nadya , Bancel Thomas , Beranger Benoit , Didier Melanie , Daniel Maxime , Bardinet Eric , Santin Mathieu , Vidal Sara Fernandez , Galléa Cécile , Rachmilevitch Itay , Shapira Yeruham , Dizeux Alexandre , Attali David , Tanter Mickael , Grabli David , Vidailhet Marie , Lehericy Stephane , Karachi Carine , Hainque Elodie , Aubry Jean-Francois
Published: November 2024

Motivation: Transcranial Ultrasound Stimulation (TUS) is a non-invasive technology for brain stimulation, particularly suited for the neuromodulation of deep brain structures. Goal(s): We investigated the behavioral effects of low-energy TUS in the thalamus in Essential Tremor patients scheduled for MR-guided ultrasound treatment. Approach: Two targets were tested: the ventral intermediate nucleus of the thalamus (VIM) and the dentato-rubro-thalamic tract (DRT). MRI was used for procedure guidance and monitoring. The effect was recorded using MR-compatible accelerometers. Results: VIM low-energy neuromodulation induced transient change in tremor power (p-value< 0.001). DRT neuromodulation reduced tremor power (p-value<0.001) with a sustained post-effect, without MR-thermometry exhibiting any significant thermal rise. Impact: High precision focusing enhanced by state of the art transcranial aberration correction allowed unprecedent transient tremor reduction in Essential Tremor patients following low-energy thalamic ultrasound stimulation under MRI guidance.
Acute versus chronic ventral lateral thalamus intrinsic connectivity after MR-guided focused ultrasound thalamotomy for essential tremor
Authors: Clark Darren , Rockel Conrad , Pichardo Samuel , Sankar Tejas , Girgis Fady , Aquino Camila , Martino Davide , Kiss Zelma , Pike G. Bruce
Published: November 2024

Motivation: To address the gap in understanding the longitudinal impact of MR-guided focused ultrasound (MRgFUS)-thalamotomy on motor network connectivity in essential tremor (ET). Goal(s): To elucidate the changes in functional connectivity within the motor network following MRgFUS thalamotomy, distinguishing between acute and chronic phases. Approach: Connectivity changes in the ventrolateral (VL) thalamus of 19 ET patients were tracked using fMRI at three intervals—pre-operation, one day, and three months post-MRgFUS. Results: Initially, both VLs showed diminished connectivity with sensorimotor regions. By three months, left VL had enhanced connections with associative and visual areas, while right VL demonstrated sustained reduced sensorimotor connectivity, reflecting hemisphere-specific functional reorganization. Impact: Mapping evolving connectivity of ventrolateral thalamus after MR-guided focused ultrasound (MRgFUS) thalamotomy enables tailored essential tremor treatments, potentially yielding better outcomes and informing treatment parameters, while also providing putative biomarkers for treatment efficacy and broader insights into neurological network management.
Functional conductivity imaging: quantitative mapping of brain activity
Authors: Rae Caroline , Cao Jun , Cassidy Ben , Ball Iain
Published: November 2024

Motivation: Theory and modelling suggest that detection of neuronal activity may be feasible using phase sensitive MRI methods. Goal(s): To demonstrate successful application of phase-based MREPT to functional tasks in brainApproach: Using bFFE optimised for fast acquisition, data were acquired from 5 participants undertaking visual stimulation or somatosensory stimulation. Electrical conductivity values extracted from phase images were fitted with the measured stimulus response function. Results: Images showed consistent activation of visual circuitry (~0.1 S/m) in both grey and white matter with similar circuit responses to somatosensory stimulation. Conductivity increased with stimulus duration or increased contrast and was faster, temporally, than BOLD. Impact: Functional conductivity imaging (funCI) reveals activity in both grey and white matter. The sensitivity, repeatability and time course of funCI shows that MRI can detect brain activation beyond changes in blood supply.
High-Frequency Oscillation-Based Rotary Saturation: a functional imaging technique for epilepsy lateralization in MRI-negative patients
Authors: Capiglioni Milena , Cardoso Pedro , Robinson Simon , Kiefer Claus , Trattnig Siegfried , Pataraia Ekaterina , Beisteiner Roland , Wiest Roland
Published: November 2024

Motivation: Delineation of the seizure onset zone (SOZ) in surgical planning for drug-resistant epilepsy requires invasive procedures. The Stimulus-Induced Rotary Saturation (SIRS) sequence targets biomagnetic field associated with epileptic discharges. Goal(s): To evaluate the efficiency of SIRS in epilepsy lateralization using high-frequency oscillations (HFOs) as biomarkers and compare it with EEG and clinical seizure semiology. Approach: We investigated 11 epilepsy patients using SIRS at a 120 Hz spin-lock frequency, assessing the localizing value at hemispheric and lobar levels. Results: SIRS-identified activations were above threshold in 8 of 11 patients, offering potential for improved SOZ localization. Hemispheric concordance was found with EEG in 7 cases. Impact: Spin-lock based rotary saturation imaging lateralized brain areas in epilepsy patients with negative MRI findings in concordance with EEG and seizure semiology. Combined with state-of-the-art non-invasive methods such as EEG, it offers potential for improved seizure lateralization.
Monitoring brain glucose metabolism using magnetic resonance fingerprinting at 9.4 T
Authors: Jiang Mou , Yuan Yaping , Zhang Lei , Chen Shizhen , Zhou Xin
Published: November 2024

Motivation: The monitoring of brain glucose metabolism plays an important role in the diagnosis of neurological diseases. Goal(s): The glucose uptake and clearance in the mouse brain were monitored following intravenous administration of glucose using magnetic resonance fingerprinting. Approach: A magnetic resonance fingerprinting imaging sequence was developed to simultaneously measure the T1, T2 and T1ρ of tissue. Results: With the intravenous administration of glucose, there was a rapid increase followed by a gradual decrease in R1, R2 and R1ρ values in the brain. Impact: The application of magnetic resonance fingerprinting in the study of brain glucose metabolism facilitates rapid and simultaneous measurement of multiple parameters, thereby yielding valuable information for the diagnosis of brain-related diseases.
Enhanced prostate imaging in ultra-low field MRI using a passive LC-resonator.
Authors: Chen Fangge , Xu Zheng
Published: November 2024

Motivation: As gold standard, MRI indeed matters in prostate imaging. The relative low image quality in ultra-low field MRI precludes its application in prostate imaging. Goal(s): Our goal was to improve prostate image quality in ultra-low field MRI, particularly emphasizing the target prostate region. Approach: We utilized an additional specially designed passive LC-resonator in imaging process. Results: By using the LC-resonator, the prostate image quality in ultra-low field MRI was improved, giving a higher image contrast to the prostate region. Impact: Adopting passive LC-resonator in imaging process is of highly cost effective, not only highlighting the target region, but offering a new imaging idea for other organs when it comes to bad SNR situations.
Evaluating simultaneously derived T2, T2*, vCBV and OEF from GE-SE EPIK in brain tumour patients
Authors: Küppers Fabian , Kassem Mohamed , Yun Seong Dae , Filss Christian , Stoffels Gabriele , Mottaghy Felix , Kooi Eline , Langen Karl-Josef , Lohmann Philipp , Shah Nadim
Published: November 2024

Motivation: Multi-contrast GE/SE acquisitions provide versatile, simultaneously acquired MR parameters, with fast, non-invasive OEF quantification proving potentially exceptionally valuable in clinical practice. Goal(s): The tumour characterisation capability of 10-echo GE-SE EPIK-derived MR parameters was evaluated in standardised tumour VOIs compared to healthy brain tissue. Approach: A full-brain 2-minute protocol was acquired from 18 tumour patients during hybrid 3T MR and FET-PET acquisitions. Quantified MR parameters were analyzed in tumour VOIs defined by FET-PET. Results: The increased T2/T2* values and decreased vCBV/OEF obtained using 2-minute GE-SE EPIK acquisitions were in agreement with literature values. Impact: Whole-brain T2, T2*, vCBV, and OEF quantification can be obtained within a 2-minute TA using 10-echo GE-SE EPIK MRI, revealing changes in tumour VOIs in agreement with literature values, potentially providing fast clinical access to MR parameters, especially OEF.
Anisotropy of Longitudinal Relaxation in White Matter: Comparison of T1 and Magnetization Transfer
Authors: Wallstein Niklas , Pampel André , Jäger Carsten , Müller Roland , Stieler Jens , Martin Sven , Morawski Markus , Möller Harald
Published: November 2024

Motivation: Studies on the orientation dependence of T1 have led to contradictory observations, indicating that this effect is not well understood. Goal(s): Our primary objective was to meticulously explore the orientation dependency of T₁ under precisely controlled and stable conditions. Approach: Comprehensive T1 (inversion recovery) and magnetization-transfer (MT) experiments were performed in fixed spinal-cord samples, with systematic variation of the fiber-to-field angle θFB . Results: No relevant T1 variation with θFB was observed in the IR experiments. However, a clear orientation dependence was consistently observed in all MT experiments,Impact: Precise quantitative MR measurements in spinal cord with varying fiber-to-field angle showed no consistent orientation dependence of T1 but a clear effect for the MT saturation, indicating the MT effects may be responsible for the previously observed T1 anisotropy.
Development of a musculoskeletal relaxometry phantom for T1, T2, and T1rho measurements
Authors: Kim Jeehun , Russek Stephen , Stupic Karl , Stoffer Cassandra , Keenan Kathryn , Rutkowski David , Kammerman Jeff , Brittain Jean , Li Xiaojuan
Published: November 2024

Motivation: There is not a commercially available musculoskeletal (MSK) relaxometry phantom. Goal(s): Develop a dedicated MSK relaxometry phantom for T1, T2, and T1rho measurement quality assurance. Approach: A cylindrical phantom with 12 vials containing modulated T1 and T2 samples was created, with an MR-visible thermometer for temperature tracking. Phantom stands were used for consistent positioning. MRI/NMR measurements were collected for longitudinal stability and temperature dependence. Results: MRI measurements were in good agreement between two vendors with CVs<3% and demonstrated longitudinal stability with CVs<3% over a 3-month period. NMR measurements showed clear changes in T1, T2, and T1rho with changing temperature. Impact: A stable MSK relaxometry phantom prototype was successfully developed and characterized, including changes with temperature. With harmonized measurement protocols, this phantom will facilitate the use of quantitative relaxometry MRI in large-scale multi-site multi-vendor trials.
A novel 3D printed anthropomorphic phantom for evaluation of MR image characteristics
Authors: Tao Shengzhen , Lin Chen , Eagle Carleigh , Zhou Xiangzhi , Pooley Robert
Published: November 2024

Motivation: The typical MRI phantoms with simple geometric inserts in homogenous background do not allow in-depth evaluation of MR image characteristics necessary for assessing advanced imaging and reconstruction techniques. Goal(s): To develop phantoms that can produce images with realistic anatomical structure that are more suitable for thorough evaluation of MR image characteristics. Approach: We developed an approach to construct novel anthropomorphic phantoms using 3D-printing technique and use an example to demonstrate the utilization of this phantom for image quality evaluation. Results: The phantom created with this approach can produce images resembling original MRI images acquired on human subjects. Impact: The phantom generated using the proposed approach allows in-depth evaluation of MR image characteristics utilizing images with realistic anatomical structure, which may be especially beneficial for developing and evaluating advanced data acquisition and reconstruction techniques.
Modular open-source imaging phantom
Authors: Tyshchenko Igor , Zeng Youheng , Blunck Yasmin , Moffat Bradford , Glarin Rebecca , Johnston Leigh
Published: November 2024

Motivation: Overcome the high cost, lack of customisation and low global uptake of standard MRI imaging phantoms. Goal(s): Design an affordable open-source MRI imaging phantom, imaging protocols and analysis tools demonstrated, showcasing their efficacy through the evaluation of slice profile and spatial resolution assessment. Approach: A complex, multilayered phantom is designed with careful material selection aimed at low cost (US$500 worth of materials) and accessible construction principles. Slice profile and resolution measurements were performed using a double-wedge and a coarse resolution grid, respectively. Results: This study has successfully produced an affordable open-source imaging phantom with detailed MRI assessment protocols. Impact: This project's affordable, open-source MRI phantom and specialised assessment protocol benefit researchers by reducing costs and encouraging collaboration. The findings on slice profiles and resolution parameters enhance MRI research, improving imaging outcomes and accessibility.
A 16-channel MR-PET array coil for high-resolution parallel transmit brain imaging at 7T
Authors: Mareyam Azma , Kirsch John , Kazemivalipour Ehsan , Scipioni Michele , Allen Magdelena , Short Jeffrey , Almurani Hammodi , Catana Ciprian , Wald Lawrence
Published: November 2024

Motivation: We are developing the Human Dynamic NeuroChemical Connectome, a high spatio-temporal resolution brain PET (HSTR-BrainPET) scanner integrated with a 7T MR systemGoal(s): To build a 16-channel PET-compatible RF coil with parallel transmit capability based on an 8-channel test array for high-resolution imaging. Approach: We designed and built multi-channel transmit-receive coils with RF screen that fits inside the spherical geometry of the PET camera. Coil performance was characterized with and without PET modules present. Results: The performance of the 8-channel coil was satisfactory. Preliminary tests with the 16-channel array showed some loss in sensitivity in the CP mode. Impact: By designing a 16-channel transmit-receive RF head coil and RF screen that both conform to the novel spherical geometry PET camera, we can acquire high-quality MR data simultaneously with PET data while also minimizing 511 keV photon attenuation.
Concurrent ultra-high field fMRI and optical imaging of hemodynamic parameters and intracellular calcium
Authors: Bernard Rebekka , Scheffler Klaus , Pohmann Rolf
Published: November 2024

Motivation: BOLD fMRI is widely used as an indirect measure of neuronal activity. However, the spatial and temporal specificity of the BOLD signal is still under debate. Goal(s): Being able to measure both hemodynamics and neuronal activity simultaneously with fMRI can help to improve interpretation of the BOLD signal. Approach: A combined in-bore setup for concurrent intrinsic optical imaging, calcium imaging and ultra-high field fMRI in rats was designed. Results: Measurements of BOLD, intrinsic hemodynamic and calcium signals with high temporal and spatial resolution reveal high correlation between these signals with specific characteristics regarding localization, vascularization and fMRI sequence. Impact: A combined in-bore setup for concurrently recording calcium, intrinsic optical signals and fMRI was developed, which can be used to investigate spatial and temporal characteristics and correlations between brain activation, hemodynamic changes and BOLD signals.
PET Recon with MR Priors: Application in Ambiguously Rated Amyloid PET Scans
Authors: Khalighi Mehdi , Zaharchuk Greg , Zeineh Michael , Davidzon Guido , Young Christina , Poston Kathleen , Mormino Elizabeth
Published: November 2024

Motivation: Uptake in the supratentorial cortex defines clinical amyloid positivity. Because of PET’s low spatial resolution, there is a spill-in effect from adjacent white-matter to gray-matter in amyloid PET scans, which may cause inconsistent rating between trained readers. Goal(s): Reduce the spill-in effect by using MR priors in PET recon to improve the consistency of reading amyloid PET scans. Approach: A recently developed PET recon with MR-priors and motion correction is applied to a set of 18F-florbetaben (amyloid) PET/MRI scans and is compared with regular TOF-OSEM PET recon using SUVR. Results: PET recon with MR priors improves reading of negative amyloid PET scans. Impact: PET-recon with MR-priors can make identifying negative cases more consistent between readers. Given how common inconsistent ratings are for amyloid-PET, methods that improve the ability to distinguish intermediate amyloid levels may be valuable for the widespread use of this modality.
Robust data-driven cerebral artery segmentation using functional magnetic resonance imaging
Authors: Xu Tianyin , Wright Adam , Koo John , Zhao Yi , Tong Yunjie , Wen Qiuting
Published: November 2024

Motivation: In this work, we address the challenge of cerebral artery segmentation when time-of-flight (TOF) imaging is unavailable. Goal(s): Develop an automatic data-driven segmentation of large cerebral arteries. Approach: Arteries were identified within the fMRI signal by leveraging large pulsation-driven fluctuations. Results: In the local subjects with TOF images, the approach displayed high levels of agreement with TOF-derived segmentation. Additionally, the segmentation demonstrated high scan-to-scan reproducibility in 430 subjects with four repeated fMRI scans from the HCP aging cohort. Lastly, the segmentation performed robustly across two different scanning protocols supporting its potential to be used for datasets with various acquisition parameters. Impact: Our robust data-driven approach reliably automatically segments the large cerebral arteries of fMRI datasets. This work enables more accessible large cerebral artery segmentation in existing MRI datasets, independent of TOF images.
Automatic Segmentation of Large Blood Vasculature in DCE-MRI Data of Brain Tumor Using Different Clustering Algorithms
Authors: Kesari Anshika , Gupta Rakesh , Singh Anup
Published: November 2024

Motivation: The presence of normal large-blood-vessels(LBV) in tumor region can impact the evaluation of quantitative DCE-MRI parameters and tumor classification. Goal(s): To develop an automated framework for segmenting LBVs present within or around the tumor region using different clustering algorithms and compare their accuracy in tumor grading. Approach: LBV masks were generated using three different clustering algorithms on the DCE-MRI derived maps CBV and Slope-2. Generated tumor mask using AI tool on FLAIR images. Statistical analysis was performed. Results: Overall, k-means clustering based algorithm provided superior performance in segmentation of LBV and tumor grading in less computational time. Impact: The proposed automatic LBV segmentation algorithm can assist radiologists in objective and accurate assessment of tumor including tumor grading. This will reduce errors in tumor assessment.
Reproducibility of intracranial vascular pulsatility on 3D cine black-blood MRI
Authors: Zhang Kaiyu , Kerwin William , Ma Xiaodong , Wang Xin , Guo Yin , Hatsukami Thomas , Mossa-Basha Mahmud , Yuan Chun , Balu Niranjan
Published: November 2024

Motivation: This research investigates the lesser-explored domain of lumen area changes in intracranial vascular pulsatility, providing insight into cerebral vasculature's mechanical behavior. Goal(s): To employ cine black-blood MRI for delineating and quantifying intracranial artery pulsatility by monitoring cardiac cycle-induced lumen variations. Approach: We utilized a sophisticated vessel analysis system to discern pulsatility within the lumen and adjacent tissues, validating our findings with reproducibility scans. Results: Cine black-blood imaging successfully visualized intracranial vascular pulsatility. The method displayed robust reproducibility in detecting lumen area changes, proving comparable to velocity pulsatility measurements. Impact: This study illuminates the often-overlooked aspect of lumen area pulsatility, with implications for a holistic assessment of vascular health and disease.
Determinants of 7T MRI microvascular function and link with small vessel disease burden in an ageing population
Authors: Pham Stanley , Linders Madouc , Streiber Anna , Dieleman Nikki , Zwanenburg Jaco , Neitzel Julia , Ikram Arfan , Vernooij Meike , Biessels Geert Jan
Published: November 2024

Motivation: Novel 7T MR techniques allow non-invasive assessment of cerebral small vessel function, potentially relevant to small vessel disease (SVD), a common cause of stroke and dementia. Goal(s): Assess determinants of small vessel function and its link to SVD lesion burden. Approach: Perforating artery blood flow velocity and pulsatility were measured with 7T MRI in 200 participants >60 years from a population-based sample and linked to vascular risk factors and white matter hyperintensity (WMH) volume using linear regression. Results: Age, blood pressure, and BMI were determinants of small vessel function. In turn, vessel function did not relate to WMH burden. Impact: In the general aging population, perforating artery blood flow velocity and pulsatility do not relate to whole-brain SVD-lesion load. Other complementary small vessel function measures should be investigated as a potential early marker of SVD.
Simulation-based optimization and experimental comparison of intracranial T2-weighted DANTE-SPACE vessel wall imaging at 3T and 7T
Authors: de Buck Matthijs , Hess Aaron , Jezzard Peter
Published: November 2024

Motivation: T2-weighted DANTE-SPACE is a promising sequence for intracranial black-blood vessel wall imaging at 7T. However, it is limited by signal and contrast variations and its performance versus 3T remains unclear. Goal(s): To optimize T2-weighted DANTE-SPACE at both 3T and 7T, and to quantitatively compare their performance. Approach: A recently introduced DANTE-SPACE simulation framework was used for protocol optimization. Data acquired from six healthy volunteers at 3T and 7T were then quantitatively compared. Results: Optimization of DANTE-SPACE parameters at 7T provides a 24% increase in vessel visibility over a literature protocol. Contrasts at 7T are 90% higher than at 3T. Impact: Through simulation-based optimization, the vessel wall contrasts from T2-weighted DANTE-SPACE at 7T were improved by 24% versus a literature protocol. When optimized and implemented at 3T, in-vivo data showed a much lower vessel wall contrast-to-noise relative to 7T.
Analysis of Bolus Arrival Time in Moyamoya Disease Using Ultra-Fast 3D Dynamic Contrast-Enhanced MR Imaging by GRASP technique
Authors: Ito Shuichi , Okuchi Sachi , Fushimi Yasutaka , Fujimoto Koji , Nakajima Satoshi , Sakata Akihiko , Otani Sayo , Sakurama Azusa , Tagawa Hiroshi , Wang Yang , Ikeda Satoshi , Umehana Masaki , Ma Yongping , Funaki Takeshi , Nakamoto Yuji
Published: November 2024

Motivation: To better understand the hemodynamics in moyamoya disease (MMD), high temporal and spatial resolution DCE-MRI using GRASP technique could estimate bolus arrival time (BAT) in MMD. Goal(s): To find optimal condition for measuring BAT and to elucidate clinical value of BAT on MMD. Approach: Thirty-seven MMD patients were included. Images with 5, 8, 13, and 21 spokes/frame were post-processed to derive time-intensity curves and estimate BATs. Results: Using the optimal 13 spokes/frame, BATs were delayed on the side with severe stenosis/occlusion and were in the order of MCA M2, basal ganglia, thalamus, and choroid plexus. Impact: Bolus arrival time in moyamoya disease estimated by using high temporal and spatial resolution 3D dynamic contrast-enhanced MR imaging using GRASP technique facilitates our understanding of the hemodynamics in moyamoya disease by elucidating regional difference.
Investigating the relationship between multi-scale perfusion and myelin content in MS
Authors: Sadrabadi Mohammadreza Soltany , Ott Lauren , Borazanci Aimee , Dortch Richard , Stokes Ashley
Published: November 2024

Motivation: This study investigates the complex pathology of multiple sclerosis (MS), focusing on the relationship between cerebral perfusion and myelin integrity. Goal(s): Utilizing selective inversion recovery (SIR) to determine myelin content through the macromolecular (PSR), and a combined spin- and gradient-echo (SAGE) sequence to assess micro- and macrovascular perfusion,Approach: This study aims to uncover the interplay of hemodynamic impairments and myelin repair in MS. Results: In a cohort of individuals with RRMS and healthy controls, we found significant correlations between PSR and microvascular perfusion within lesions, suggesting a possible link between myelin integrity and cerebral blood flow. Impact: Uncovering specific pathological changes in MS lesions may enhance diagnostic accuracy and disease monitoring. Such insights could also drive the creation of new therapies focused on remyelination and neuroprotection, potentially altering the treatment landscape for MS.
Depicting ability of 7 Tesla MRA for lenticulostriate arteries: practical assessment based on intraoperative video of aneurysm neck clipping
Authors: Yanagihara Wataru , Koji Takahiro , Kubo Yoshitaka , Akamatsu Yosuke , Sasaki Makoto , Wada Tsukasa , Fujiwara Shunrou , Ogasawara Kuniaki
Published: November 2024

Motivation: To clear the depicting ability for the lenticulostriate arteries at 7 Tesla in patients with unruptured the middle cerebral artery aneurysm. Goal(s): MRA at 7 Tesla can depict the lenticulostriate arteries more than that at 3 Tesla in assessment using the intraoperative video. Approach: Comparison of accuracy of identification of LSAs at standard 3D TOF imaging at 3T, standard 3D TOF imaging at 7Tand high-resolution 3D TOF at 7T, using the findings of intraoperative video as the reference. Results: LSAs were identified more accurately by HR7T 3D TOF than by S3T 3D TOF. Impact: In patients with an unruptured MCA aneurysm, LSAs were identified more accurately by HR7T 3D TOF than by S3T 3D TOF; however, the ability to depict the vessels could depend on the resolution rather than the signal-to-noise ratio.
Time-dependent diffusion MRI-based microstructural mapping for preoperative prediction of intraductal component in invasive breast cancer
Authors: Xu Hao , Deng Heping , Liu Jieke , Chen Meining , Feiweier Thorsten , Zhou Peng
Published: November 2024

Motivation: Conventional MRI falls short in detecting specific imaging markers for an intraductal component(ductal carcinoma in situ) in invasive breast cancer (IBC-IC), thus affecting breast-conserving surgery. Advanced MRI techniques can help in preoperative evaluations. Goal(s): We evaluated the efficacy of td-dMRI for preoperatively identifying IBC-IC for surgical planning. Approach: We used td-dMRI to examine microstructural mapping in IBC patients by IMPULSED model, focusing on the parameters Dex, d, and vin to differentiate IBC-IC from IBC. Results: We revealed that elevated d and Dex and reduced vin are distinct microstructural markers of IBC-IC, which might facilitate surgical planning for IBC-IC patients. Impact: Parameters derived from td-dMRI have the potential to act as imaging biomarkers for distinguishing IBC-IC, thereby enhancing the precision of breast-conserving surgery planning.
Image space formalism of k-space interpolation networks for analytical expression of noise characteristics
Authors: Dawood Peter , Breuer Felix , Homolya István , Jakob Peter , Blaimer Martin
Published: November 2024

Motivation: Robust Artificial Neural Networks for k-space Interpolation (RAKI) exhibit superior image reconstructions compared to traditional Parallel Imaging. It is crucial to thoroughly characterize RAKI to gain insights into its functionality and stimulate further enhancements. Goal(s): Exploring how k-space interpolation with convolutional neural networks can be transformed into image domain to obtain an analytical description of noise characteristics. Approach: The nonlinear activation in k-space is expressed as elementwise multiplication. This can be transformed into convolution in image space. Results: The proposed image space formalism yields image reconstructions quasi-equivalent to k-space interpolation. The analytical expression of noise characteristics is in correspondence with Monte Carlo simulations. Impact: We propose an image space formalism for k-space interpolation with convolutional neural networks. This enables an analytical expression of the noise characteristics, analogous to g-factor maps in traditional parallel imaging methods.
3D Free-Breathing Ungated Spiral bSSFP Functional Cardiac Imaging Using a Deep Image Prior
Authors: Hamilton Jesse , Cruz Gastao Lima da , Seiberlich Nicole
Published: November 2024

Motivation: Real-time imaging methods are useful for patients with limited breathhold capacity or arrhythmias, but are typically limited to 2D scans that prevent evaluation of wall motion in 3D over the heart. Goal(s): The goal of this project is to develop a technique for 3D real-time (free-breathing ungated) cine imaging. Approach: The proposed method combines a highly undersampled 3D stack-of-spirals trajectory with a deep image prior reconstruction, which does not require ground truth training data. Results: Real-time 3D imaging is demonstrated in healthy subjects with temporal resolutions of 36ms per volume at 1.5T and 58ms per volume at 0.55T. Impact: Real-time 3D imaging could enable streamlined cardiac MRI exams, with whole-heart 3D cine images obtained in 10s without breathholds or gating. This technique may also simplify quantification compared to 2D real-time methods, since motion is synchronized over all partitions.
In vivo mapping of the intra-cortical vasculature and layer-specific changes in Δχ and ΔR2* of human cerebral cortex using USPIO-MRI at 7T
Authors: Li Chenyang , Chen Yongsheng , Buch Sagar , Sun Zhe , Jiang Li , Muccio Marco , Haacke E. Mark , Ge Yulin
Published: November 2024

Motivation: In vivo imaging of intra-cortical vessels of human brain, including penetrating arteries, veins and capillary density are still scarce. Goal(s): To reconstruct the in vivo intra-cortical vessels of the human brain and estimate the cortical layer-specific changes in susceptibility (χ) in the presence of superparamagnetic iron oxides. Approach: With aid of Ferumoxytol at 7T, high resolution gradient echo imaging was implemented to reconstruct pre-/post-SWI, R2* and χ maps. Results: Intra-cortical penetrating arteries and veins can be differentiated by pre- and post-contrast SWI. Changes in R2* and χ revealed variations reflective of capillary density across different layers, which is in agreement with histological findings. Impact: This study provides in vivo imaging characterization of intra-cortical vessels of human brain using high-resolution Ferumoxytol-enhanced SWI at 7T. Utilizing changes in R2* and χ enables us delve deeper into the laminar distribution of capillary density across various cortical layers.
Time-dependent diffusion discriminates healthy and hypertrophic mouse hearts ex vivo
Authors: Afzali Maryam , Khazin Leah , Foster Richard , Mueller Lars , Coveney Sam , Plein Sven , Dall'Armellina Erica , Yuldasheva Nadira , Schneider Jürgen , Teh Irvin
Published: November 2024

Motivation: Oscillating gradient spin-echo (OGSE) diffusion MRI provides information about the cardiac microstructure that is complementary to conventional pulsed gradient spin echo (PGSE). Goal(s): Using gradient waveforms with different frequencies enables the assessment of diffusion at sub-cellular length scales. Approach: OGSE diffusion tensor imaging (DTI) was applied in the ex vivo mouse heart to investigate the ability of OGSE to disentangle hypertrophic from healthy hearts. Results: Our results show that hypertrophic hearts exhibited significantly different OGSE parameters (8 of 10) compared to control hearts. These and DTI observations are in agreement with expected microstructural changes. Impact: Gradient waveforms with different frequencies enable the assessment of diffusion at sub-cellular length scales. OGSE may potentially serve as an imaging biomarker, to enhance the specificity of measurements with DTI.
Whole Heart, Whole Cardiac Cycle, Motion-Resolved, 3D T2*-Mapping Reveals Myocardial T2* Differences Between Wild-Type and HCM Mice
Authors: Shalikar Shahriar , Malagi Archana , Guan Xingmin , Huang Yuheng , Laghzali Oumaima , Yang Chia-Chi , Dharmakumar Rohan , Waiczies Sonia , Niendorf Thoralf , Yang Hsin-Jung , Ku Min-Chi
Published: November 2024

Motivation: To explore various stages of myocardial pathophysiology and improve prediction and interception of disease progression by capturing myocardial T2* variations across cardiac cycle. Goal(s): To establish a framework that operates independently of ECG- and respiratory-gating, enabling cinematic, whole-heart myocardial T2*-mapping in mouse models. Approach: A tailored framework was developed using modified Multi-Gradient-Echo (MGE) sequence and Low-Rank-Tensor (LRT) reconstruction technique. In vivo study was performed. Results: Our preliminary findings demonstrate the feasibility of flow-compensated, free breathing, fully ungated, cardiac motion-resolved, whole heart and whole cardiac cycle coverage CINE imaging and T2* mapping in healthy and diseased mice heart. Impact: The differences in myocardial T2* obtained for wild-type mice and HCM model provide a new metric ΔT2*,rel for myocardial tissue characterization, and springboard to inform on the different stages of myocardial pathophysiology and improve prediction and interception of disease progression.
Assessment of Cardiomyopathy at Different CKD Stages using Free-breathing Simultaneous Myocardial T1, T2 and T1ρ Mapping: Initial Experience
Authors: Lyu Zhenfeng , Hua Sha , Gong Yiwen , Hu Peng , Qi Haikun
Published: November 2024

Motivation: Chronic kidney disease (CKD) leads to significantly increased risk of cardiovascular death, highlighting the need for a non-contrast and non-invasive method to detect potential cardiomyopathy. Goal(s): To evaluate the performance of cardiac multi-parametric mapping in assessing cardiomyopathy in CKD patients. Approach: A recently proposed free-breathing multi-parametric mapping (FB-MultiMap) technique was employed to obtain myocardial T1, T2 and T1ρ maps of CKD patients. The parametric values were compared between healthy controls, stage 2, and stage 3-5 CKD patients. Results: Myocardial T1, T2 and T1ρ exhibit significant differences between early-stage and moderate-to-end-stage CKD patients, indicating their potential for assessing the progression of cardiomyopathy in CKD. Impact: FB-MultiMap may serve as an effective and easy-to-use tool for early diagnosis and monitoring of cardiomyopathy in CKD, potentially improving the outcome of CKD patients.
MRI-based Biological Age Estimation for Multiple Organs in the UK Biobank Cohort
Authors: Ecker Veronika , Früh Marcel , Yang Bin , Gatidis Sergios , Küstner Thomas
Published: November 2024

Motivation: MRI is a valuable tool for providing health-related information, including visualizing age-associated changes. Aging is influenced by chronic diseases, and assessing the true organ-specific biological age is essential for accurate diagnosis. Goal(s): Development of an organ-specific age estimation for investigation in large imaging cohort with associated non-imaging information. Approach: While prior studies focused on age estimation from non-imaging data or single organs, we propose a multi-organ age estimation framework, operating on brain, cardiac, and abdominal MRIs, and OCT scans. Results: Our results prove the feasibility of imaging-based organ age estimation and initiate further investigations to identify risk factors for accelerated aging. Impact: Reliable imaging-based estimation of biological age in multiple organ systems facilitates research efforts to identify risk factors of accelerated aging, advancing the goal of age-related phenotyping.
RF Shield design for transmit coils to reduce acoustic noise in MRI
Authors: Gunamony Shajan , Boulant Nicolas , Feinberg David
Published: November 2024

Motivation: Eddy currents induced in the RF shield cause vibrations which generate acoustic noise. Goal(s): To develop an RF shield that minimizes eddy currents and preserve the B1+ efficiency. Approach: It was established that eddy-currents induced in the RF shield of the transmit coil are the primary source of acoustic noise in our 7T scanner. Therefore, the conventional slotted double layered RF shield was replaced by a segmented phosphor bronze mesh (PBM) to minimize eddy-currents and acoustic noise. Results: Measurements performed at both ear locations of an anthropometric phantom demonstrate that the segmented PBM-based RF shield reduces the acoustic noise by up to 10dB. Impact: Acoustic noise reduction could be achieved by using segmented PBM without compromising the transmit B1 field compared to the conventional double-layered slotted shield. Further improvements might be achieved with different mesh configurations besides the one implemented in this work.
Evaluation of Metal-Artifact Reduction Techniques at 7T: Hardware adaption, phantom study, and preliminary in vivo results
Authors: Kraff Oliver , Deuermeier Niklas , May Markus , Pfaffenrot Viktor , Theisejans Jana , Theysohn Jens , Quick Harald
Published: November 2024

Motivation: Advanced metal-artifact reduction sequences (MARS) are currently only available in parallel transmission (pTx) research mode at 7T, while clinically approved RF coils are single-channel transmit (sTx) coils. Goal(s): Our goal was to build an adapter to connect a sTx knee coil to a pTx system, and to evaluate MARS techniques in phantom and in vivo scans. Approach: An evaluation of artifact reduction using advanced MARS techniques was performed in a phantom study. Knees of three volunteers with metallic suture plates were imaged. Results: Optimized bandwidth and view-angle-tilting (VAT) effectively reduced metal artifacts while keeping acquisition time and SAR load acceptable. Impact: A hardware adaption for connecting a sTx coil to a pTx system was evaluated for safe in vivo usage. The application of MARS was demonstrated for the first time at 7T in volunteers with metallic suture plates after ACL reconstruction.
Design of RF front-end circuit module for human 14T MRI system
Authors: Yang Gang , Wang Weimin
Published: November 2024

Motivation: The ultra-high field magnetic resonance imaging system can obtain ultra-high sensitivity and signal-to-noise ratio magnetic resonance imaging information, has become an important tool for basic research in brain science . Goal(s): However, with the increase of field strength and operating frequency, the RF signal processing module, faces problems such as clutter interference, mirror frequency interference, which seriously affects the performance of the RF system and the final image quality. Approach: We have solved these problems using methods such as secondary mixing. Results: After key parameter testing and verification, it meets the application requirements of the human 14T ultra-high field magnetic resonance imaging system. Impact: Our work has provided conditions for the construction of multi-channel RF modules in ultra-high fields, improving the quality of RF signal processing. Provided a hardware foundation for improving the quality of MRI images in ultra-high fields.
A stitching method for dynamic field monitoring using NMR probes
Authors: Zhang Zihao , Auerbach Edward , Bratch Alexander , Grant Andrea , Zhuo Yan , He Sheng , Chen Lin , Ugurbil Kamil , Wu Xiaoping
Published: November 2024

Motivation: NMR field probe methods for field monitoring are limited by probe signal loss due to relaxation, dephasing, or both. Goal(s): To develop a method for characterizing sequences with higher resolution or readout length than allowed by current field monitoring approaches. Approach: Long-duration 2D spiral readout gradients were characterized by acquiring and stitching multiple segment-specific dynamic field measurements per segmentation of the readout gradient determined by a signal loss model. Results: For both long-duration and ultrahigh-resolution readouts, our method resulted in plausible 0th-2nd order dynamic field measurements throughout the entire spiral readout, correcting erroneous k-space traversal observed with a traditional approach. Impact: The proposed stitching method provides an effective means to characterize challenging imaging gradients using commercially available hardware and without assuming a linear gradient system, thereby having utility for dynamic field measurements in ultrahigh-resolution MRI using a standard field monitoring system.