| 13:45 | 1257.
 | Double Inversion Recovery in myocardial Arterial Spin Labeling (ASL) for reduced physiological noise Maša Božić-Iven1,2,3, Yi Zhang3, Qian Tao3, Stanislas Rapacchi4, Lothar R. Schad1, and Sebastian Weingärtner3
1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany, 2Mannheim Institute for Intelligent Systems in Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany, 3Department of Imaging Physics, Delft University of Technology, Delft, Netherlands, 4Centre de Resonance Magnetique Biologique et Medicale, Aix-Marseille Universite, Marseille, France Keywords: Arterial Spin Labelling, Arterial spin labelling, Myocardial perfusion Motivation: Myocardial Arterial Spin Labeling (myoASL) presents a promising contrast-agent-free approach for assessing myocardial blood flow (MBF), but its clinical translation is hampered by high levels of physiological noise (PN). Goal(s): We introduce double inversion recovery (DIR) preparations for FAIR-myoASL to mitigate sensitivity to heart rate variations and reduce PN. Approach: A flip-back inversion pulse was added immediately after the FAIR-labeling, to allow for near-complete recovery and, thus, for more effective cancellation of the myocardial background signal in the presence of heart rate variations. Results: Using DIR preparations in vivo, led to a PN reduction of up to 66 % compared to conventional myoASL. Impact: FAIR-myoASL with double inversion recovery (DIR) labeling can compensate for fluctuating myocardial background signals due to heart rate variability. In vivo, experiments suggest that DIR-preparations substantially reduce PN, thus, improving overall robustness and potentially facilitating broader clinical translation of myoASL. |
| 13:57 | 1258.
 | Time-Resolved pCASL MRA Using A Multi-Echo 3D-Radial SPGR Sequence Andreas Petrovic1,2, Martin Soellradl1,2, Thomas Okell3, Leon Lai1,2, Shalini A Amukotuwa1,2, and Roland Bammer1,2
1Department of Diagnostic Imaging, Monash Health, Melbourne, Australia, 2Department of Radiology, Monash University, Melbourne, Australia, 3Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom Keywords: Arterial Spin Labelling, Arterial spin labelling Motivation: To improve signal, spatial and temporal resolution, and acquisition time for time resolved ASL imaging for cerebral angiography. Goal(s): To exploit a time-resolved multi-echo radial 3D ASL sequence to acquire ASL MRA data in a shorter amount of time. Approach: We performed three flip angle optimized scans with a 1, 2, and 3 echo readout, respectively, and compared image quality and acquisition time. Results: Using a 3-echo readout, scan time could be reduced from 9:32 min to 6:23 min, without the loss of image quality. Multi-echo scans even showed more details than in the single-echo case. Impact: Multi-echo
3D radial ASL angiography enables substantial scan time reduction for
high-resolution time-resolved cerebral angiography. This will improve clinical
applicability and scanner throughput, avoid the use of contrast agents, and is
of direct benefit to patients. |
| 14:09 | 1259.
 | Self-Supervised SUper-Resolution ASL Enhancement based on Conditional Diffusion Models (SURED) Yunzhi Xu1, Liangchen Shi1, Jiaxin Zheng1, Jiaxin Li1, Yu Zeng1, Weiying Dai2, David Alsop 3, and Li Zhao1
1College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, 2Department of Computer Science, State University of New York, Binghamton, NY, United States, 3Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States Keywords: Arterial Spin Labelling, Arterial spin labelling, Super-resolution, Conditional diffusion model Motivation: Arterial spin labeling (ASL) MRI is a non-invasive technique used for measuring perfusion. However, the resolution of ASL is limited by its low SNR. Goal(s): to propose an ASL super-resolution method based on a self-supervised training strategy and the conditional diffusion model. Approach: Synthetic high resolution ASL images were generated by utilizing paired T1w images and low-resolution ASL images. A modified conditional diffusion model was trained to simultaneously achieve resolution enhancement and denoising. The proposed model was tested on simulated and volunteer images. Results: The proposed network demonstrates superior enhanced image details, improved SNR, and preserved original contrast in conventional low-resolution ASL images. Impact: The proposed method enhanced the ASL images without requiring the high-resolution ASL for training. It enables super-resolution ASL images from 4 minutes scans to approach those acquired in 17min. |
| 14:21 | 1260.
 | Vessel-Encoded Arterial Spin Labeling at 7 Tesla Hongwei Li1, Yang Ji2, He Wang1,3, Zhensen Chen1,3, Joseph G. Woods2, and Thomas W. Okell2
1Institute of Science and Technology for Brain-inspired Intelligence, Fudan University, Shanghai, China, 2University of Oxford, Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, Oxford, United Kingdom, 3Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China Keywords: Arterial Spin Labelling, Arterial spin labelling, ultra-high field Motivation: Vessel-encoded arterial spin labeling (VEASL) allows the visualization of collateral blood flow and blood supply to lesions, but has limited SNR. At ultra-high field, ASL benefits from significantly improved SNR and longer blood T1 relaxation time. However, B0 field inhomogeneity can reduce labeling efficiency and disrupt encoding patterns. Goal(s): Implementing VEASL robustly at 7 Tesla. Approach: Optimized ASL parameters, dynamic B0 shimming and OES-based correction methods were used to mitigate the impact of B0 field inhomogeneity. Results: Good vascular territory maps, labeling both the neck and above the circle of Willis, were achieved, including at high spatial resolution. Impact: We demonstrate the first vessel-encoded ASL perfusion maps at ultra-high field, and the vascular
territory maps significantly improved after applying B0 correction techniques,
with the potential to push for even higher spatial resolution. |
| 14:33 | 1261.
 | Sub-space Low-rank Imaging for mapping of blood-brain barrier Water Exchange Rate (SLIWER) using multi-PLD diffusion-weighted pCASL Xingfeng Shao1, Chenyang Zhao2, Rong Guo3,4, Qinyang Shou2, Zhi-Pei Liang4,5, Keith S St Lawrence6,7, and Danny J.J. Wang2
1Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Arcadia, CA, United States, 2Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 3Siemens Medical Solutions USA, Inc., Urbana, IL, United States, 4Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 5Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 6Lawson Health Research Institute, London, ON, Canada, 7Department of Medical Biophysics, Western University, London, ON, Canada Keywords: Arterial Spin Labelling, Permeability, Blood-brain barrier, water exchange, cerebral small vessel disease Motivation: Non-invasive MRI mapping of the blood-brain barrier (BBB) function using water as an endogenous tracer can be a valuable tool for early detection of subtle BBB dysfunctions. Goal(s): To develop an advanced MRI technique and reconstruction methods for reliable BBB water exchange rate (kw) mapping. Approach: We introduce a Sub-space Low-rank Imaging method for mapping BBB Water Exchange Rate (SLIWER) with an innovative pulse sequence termed motion compensated diffusion weighted pCASL (MCDW-pCASL). Results: The SLIWER method demonstrated high test-retest reliability, indicating its potential in clinical settings, such as in evaluating cerebral small vessel disease (cSVD). Impact: We developed a reliable tool for early BBB dysfunction detection, potentially transforming the diagnosis and treatment of neurological disorders such as cerebral small vessel disease. |
| 14:45 | 1262.
 | High-Fidelity ASL Perfusion Imaging Using Unsuppressed Water Signals in MR Spectroscopic Imaging Rong Guo1,2, Xingfeng Shao3, Yudu Li2,4, Yibo Zhao2,5, Wen Jin2,5, Yao Li6, Danny JJ Wang3, Brad Sutton2,4,7, and Zhi-Pei Liang2,5
1Siemens Medical Solutions USA, Inc., Urbana, IL, United States, 2Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Laboratory of FMRI technology (LOFT), USC Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 4National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 5Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 6School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, 7Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States Keywords: Arterial Spin Labelling, Arterial spin labelling, Spectroscopy Motivation: ASL and MRSI experiments are currently performed using different sequences, and EPI-based ASL methods suffer from spatial distortion and limited SNR. Goal(s): To develop a water unsuppressed MRSI based imaging method for high-fidelity ASL-based perfusion imaging. Approach: The SPICE sequence was integrated with a PASL module for ASL acquisition, and a GS model-based method was used for image reconstruction. Results: The proposed method achieved ASL at 2×2×2 mm3 resolution and MRSI at 2×3×3 mm3 within 9 minutes in total. Compared with typical EPI-based methods, the resulting ASL images were free from spatial distortion, and had adequate SNR within a short scan time. Impact: This work presents a new method for
high-fidelity ASL-based perfusion imaging combining with MRSI-based metabolic
imaging. With further development, it may provide a powerful brain imaging tool
for both functional studies and clinical applications. |
| 14:57 | 1263.
 | MULti-TImepoint VElocity-selective Reconciled with Spatially-sElective (MULTIVERSE) ASL: Pushing the Limit of Arterial Transit Time Feng Xu1,2, Dapeng Liu1,2, Dan Zhu1,2, Anja Soldan3, Marilyn Albert3, Martin Lindquist4, Doris D. M. Lin1, and Qin Qin1,2
1The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Department of Neurology, Johns Hopkins University, Baltimore, MD, United States, 4Department of Biostatistics, Johns Hopkins University, Baltimore, MD, United States Keywords: Arterial Spin Labelling, Perfusion, Cerebral blood flow, arterial transit time, multi time point, arterial spin labeling 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. |
| 15:09 | 1264.
 | Iso-1.25mm Whole-cerebrum pCASL at 7T for Mapping Depth-dependent Cortical Gray Matter and Tract-specific White Matter Cerebral Blood Flow Chenyang Zhao1, Fanhua Guo1, Qinyang Shou1, Xingfeng Shao1, Yuan Li2, Shuo Huang2, Yonggang Shi2, and Danny JJ Wang1,3
1Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 2Neuro Image Computing Research (NICR), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, 3Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States Keywords: Arterial Spin Labelling, Arterial spin labelling, 7T, Compressed Sensing Motivation: Mapping CBF in the whole cerebrum extent at a microvascular level at 7T has been hampered by SNR, susceptibility artifacts, BOLD effect, and field inhomogeneity. Goal(s): We aim to achieve an isotropic 1.25 whole cerebrum pCASL imaging. Approach: We developed a pCASL sequence which incorporates recent optimizations of labeling and background suppression and a 3D TFL readout. Poisson-disc undersampling and compressed sensing were used to improve image quality. Results: CBF mapping with high SNR and resolution was achieved, revealing depth-dependent CBF and an inverse relationship between tract-specific CBF and fractional anisotropy. Impact: The proposed pCASL imaging technique will impact neuroscientists by enabling fine-grained mapping of CBF at microvascular level in cortical gray matter and white matter at 7T. |
| 15:21 | 1265.
 | Optimization of Echo Time for BOLD Dynamic Susceptibility Contrast MRI THUY THI LE1, SANG HAN CHOI1, CHAN HEE LEE1, GEUN HO IM1, and SEONG-GI KIM1
1Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea, Suwon, Korea, Republic of Keywords: Perfusion, Perfusion, TE-dependency Motivation: Achieving accurate quantification of absolute CBV and CBF in BOLD-DSC depends on maximizing the hypoxia-induced signal changes and accurately determining the arterial input function. Goal(s): The choice of echo time affects both baseline signal-to-noise ratio and hypoxia-induced changes1,2, our study aimed to investigate the effects of different TEs on the quantification of CBV and CBF. Approach: We systematically varied TE within the range of 11.57 ms to 20 ms , measured hypoxia-induced signal changes in arterial, venous, and somatosensory tissue voxels, and quantified perfusion metrics. Results: We discovered that a shorter TE, which produces sufficient signal changes without causing arterial peak saturation, is preferable. Impact: Shorter
TE leads to less hypoxia-induced signal changes, while longer TE decreases
baseline SNR and increase the risk of arterial signal saturation. This signal
saturation leads to the underestimation of AIF, and consequently, overestimation
of perfusion quantification. |
| 15:33 | 1266.
 | Validation and assessment of venous transit time in the human brain using VICTR MRI Wen Shi1,2, Dengrong Jiang2, Zhiyi Hu1,2, Kaisha Hazel2, George Pottanat2, Ebony Jones2, Cuimei Xu2, Vivek Yedavalli2, Doris Lin2, Sevil Yasar3, Yulin Ge4, Abhay Moghekar3, and Hanzhang Lu1,2
1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States Keywords: Velocity/Flow, Perfusion, Transit Time, Vein Motivation: Venous transit time (VTT) is insufficiently investigated and can be a useful marker for clinical populations with abnormalities in the cerebral venous system. Goal(s): To further verify a novel non-contrast VICTR MRI and investigate advanced VTT properties and their age effects in the brain. Approach: We compared the VTT from VICTR and a contrast-based method. Statistical properties of VTT distribution were studied in a caffeine challenge and compared between young and older subjects. Results: VTT from VICTR MRI showed great agreement with contrast-based VTT. The mean, peak, and spread of VTT increased in the caffeine challenge. VTT is longer in the older subjects. Impact: VICTR MRI can measure venous transit time in
the adult brain which increases with age. The non-contrast measurement of venous
transit time paves the way for several research avenues to better understand
vascular function in the normal and pathological brain. |