| Computer # |
| 4453.
 | 129 | A Comparative Analysis of CEST Techniques for Mapping Muscle Creatine and Phosphocreatine at 3T Licheng Ju1, Kexin Wang1, Michael Schär1, Su Xu2, Joshua Rogers2, Dan Zhu1, Qin Qin1, Robert G. Weiss1, and Jiadi Xu1
1Johns Hopkins University, Baltimore, MD, United States, 2University of Maryland, Baltimore, MD, United States Keywords: CEST / APT / NOE, CEST & MT Motivation: Creatine and phosphocreatine metabolites imaging at 3T are essential for related disease in muscle. Goal(s): Estimate creatine proton exchange rate in muscle; Simultaneous mapping of PCr and Cr by PLOF CEST method at 3T. Approach: Antemortem and postmortem animal study was to validate PCr/Cr CEST peak position and creatine exchange rate. Three types of CEST acquisition methods were compared on human leg muscle. Results: Z-spectra in mouse hindlimb before and after euthanasia indicated CrCEST is a slow-exchanging process (<150 s-1). This allowed us to simultaneously extract PCr/CrCEST signals and mapping in muscle at 3T using the PLOF method on both human and animal. Impact: Amide, Cr, and PCr CEST in
the skeletal muscle can be mapped simultaneously at 3T by PLOF CEST within a
clinically feasible acquisition duration, which has potential to assist
in the diagnosis of related diseases. |
| 4454.
 | 130 | A generalized QUCESOP method with evaluating CEST peak overlap Yi Wang1, Yang Fan2, Xiaolei Song3, and Jia-Hong Gao4
1Public Health Science and Engineering College,Tianjin University of Traditional Chinese Medicine, Tianjin, China, 2MR Research China, GEHealthcare, Beijing, China, 3Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, 4Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China Keywords: CEST / APT / NOE, CEST & MT Motivation: When quantifying the CE-parameters (fb, kb and R2b) of the specific CEST solute with existence of other unknown solutes, the peak overlap condition needs to be assessed to evaluate the reliability of the quantification result. Goal(s): To develop a method for CE-parameters quantification and peak overlap assessment. Approach: CEST data was acquired with various saturation offsets and powers. When fitting the targeted CE-parameters, the peak overlap was evaluated using RMSE between the trajectories of the acquired and synthesized data. Simulation and experiments were taken to test the performance. Results: The feasibility of the approach in CE-parameters quantification and peak overlap assessment was verified. Impact: The proposed method would be helpful for evaluating the reliability of the empirically set model for CE-parameters quantification, and then that of the quantification result. |
| 4455.
 | 131 | Clinical Pulsed CEST MRF Optimization using the Cramer-Rao Bound and Sequential Quadratic Programming Nikita Vladimirov1, Simon Weinmüller2, Moritz Zaiss2,3,4, and Or Perlman1,5
1Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel, 2Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 3Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany, 4Department of Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany, 5Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel Keywords: CEST / APT / NOE, CEST & MT, MRF Motivation: The lack of a protocol optimization technique suitable for practical pulsed acquisition impedes the clinical translation of CEST MRF. Goal(s): To develop a pulsed CEST MRF protocol optimization method, enabling improved parameter discrimination ability and accelerated acquisition. Approach: The Cramer-Rao bound for variance assessment was employed on Bloch-McConnell-based simulated signals, followed by a numerical sequential quadratic programming optimization of MRF saturation pulse powers. Validation was performed using L-arginine phantoms for preclinical (7T) and clinical (3T) scanners. Results: The proposed optimization approach resulted in significantly lower CEST-MRF reconstruction error (p<0.001) compared to baseline and a drastically short acquisition time (<20 s). Impact: A pulsed CEST MRF optimization technique was
developed, bridging the gap imposed by the lack of accurate
analytical solutions and CEST optimization methods for practical clinical
settings. The technique increases
the translation potential of quantitative and rapid CEST
imaging. |
| 4456.
 | 132 | Towards Temperature-Corrected pH Mapping using CEST Imaging: Quantification of the Underlying Calibration as a Function of Temperature Philip S Boyd1, Jana C Lechner1,2, Jannis B Wirtz1,2, Mark E Ladd1,2,3, Peter Bachert1,2, and Andreas Korzowski1
1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany, 3Faculty of Medicine, University of Heidelberg, Heidelberg, Germany Keywords: CEST / APT / NOE, CEST & MT Motivation: CEST-based pH mapping relies on a strongly temperature-dependent calibration, yielding the parameter kc characterizing the exchange rate. Previously, this calibration has only been performed at T=37°C, thus impeding quantitative pH mapping at different temperatures. Goal(s): Enabling more reliable, i.e. temperature-corrected, quantitative CEST-based pH mapping. Approach: We quantified the temperature dependency of kc(T) for amide, amine and guanidino protons at B0=9.4T using creatine and protamine model solutions at various pH and temperatures. Results: For all proton species, the measured kc(T) showed exponential temperature dependencies with doubling of kc(T) for distinct temperature increases (ΔT=Tdouble) of around 4−11°C. Interestingly, each proton species exhibited a characteristic Tdouble. Impact: These findings enable CEST-based pH
mapping at any desired temperature, which, previously, has only been possible
at T=37°C. Prospectively, quantitative pH mapping will now also be possible in anatomical
regions, e.g. human lower leg, where temperatures may deviate from T=37°C. |
| 4457.
 | 133 | B1 inhomogeneity corrected APT MRI based on direct saturation removed omega plot model at 5 T Qiting Wu1, Ye Li1, Dong Liang1, Hairong Zheng1, and Yin Wu1
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China Keywords: CEST / APT / NOE, CEST & MT Motivation: B1 inhomogeneity correction is critical in CEST MRI. Reliable correction methods are desired. Goal(s): This study developed a B1 inhomogeneity correction method based on a direct saturation removed omega plot model and tested its performance in human brain APTw imaging at 5 T. Approach: Four healthy volunteers were scanned under four B1 levels. Corrected signal at nominal B1 was calculated from the omega plot model determined from either two or four B1 levels. Results: B1 inhomogeneity-induced artifact was shown on uncorrected APTw images, which was effectively mitigated after correction. Comparably homogeneous APTw maps were obtained between two and four B1 levels.
Impact: The proposed method enables reliable B1 inhomogeneity correction from at least two B1 levels, providing an efficient way to improve quantitative CEST MRI, especially on high-field scanners. |
| 4458.
 | 134 | A reassessment of quasi-steady-state enhanced T1 normalization in quantitative CEST analysis Phillip Sun1
1Emory University, Atlanta, GA, United States Keywords: CEST / APT / NOE, Tumor Motivation: Correction of T1 contribution in quantitative CEST MRI often assumes an equilibrium CEST signal. However, most CEST scans were not and will unlikely to be performed under equilibrium conditions. Goal(s): To investigate T1 correction and improve CEST quantification using CEST scans under practical scan (non-equilibrium) protocols. Approach: We performed numerical simulation and in vivo experiments to evaluate T1 correction without and with quasi-steady-state analysis. Results: Our study demonstrated that QUASS postprocessing enhances the accuracy of T1 correction with the AREX metric independent of the RF saturation time, relaxation delay, and T1. Impact: Our study provides a practical qCEST solution that lays the foundation for future clinical translation to improve the quantification and specificity of CEST imaging. |
| 4459.
 | 135 | Comparison between a new quantitative APT parameter APT_T1 by solving Bloch equation of multiple pool model and MTR_Rex Mitsuharu Miyoshi1, Kazuhiro Oguchi2, and Tetsuya Wakayama1
1GE HealthCare, Hino, Japan, 2Jisenkai Brain Imaging Research Center, Nagano, Japan Keywords: CEST / APT / NOE, CEST & MT, NOE Motivation: Quantitative parameter is required for APT. Goal(s): Comparing a new quantitative APT parameter APT_T1 (the ratio of APT transfer rate to longitudinal relaxation rate) with MTR_Rex Approach: APT_T1 was calculated by solving the Bloch equation of multiple pool model. APT_T1 was compared with MTR_Rex in numerical simulation and a clinical case. Results: MTR_asym was influenced by rNOE and differed from MTR_Rex. On the other hand, although calculation methods of APT_T1 and MTR_Rex were different, APT_T1 approximated MTR_Rex under the condition with strong CEST RF. APT_T1 and MTR_Rex can be used as complementary quantitative APT parameters. Impact: A new quantitative APT parameter APT_T1 was
calculated by solving Bloch equation of multiple pool model. APT_T1 approximated MTR_Rex under
the condition with strong and long CEST RF with 100% duty cycle. |
| 4460.
 | 136 | Accelerating CEST-MRI for 3D renal imaging Xiaojing Wang1, Ivan Dimitrov2,3, Jochen Keupp4, Ananth Madhuranthakam1,3, Holger Eggers4, Alexander Asturias1, and Elena Vinogradov1,3
1Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, 2Philips Healthcare, Gainesville, FL, United States, 3Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 4Philips Research, Hamburg, Germany Keywords: CEST / APT / NOE, CEST & MT Motivation: CEST-MRI is gaining recognition as a valuable tool for characterization of tumors and other ailments. However, its application in body imaging is still relatively limited. Specifically, applications to renal imaging are hampered by fat artifacts, motion, and limited coverage. Goal(s): The goal of our work is to achieve reliable renal CEST MRI. Approach: We are developing and compare acceleration of 3D GRE multi-point Dixon methods, to work in conjunction with timed breathing. The acquisition acceleration strategies include Compressed Sensing (CS) and CS with CASPR k-space sampling pattern. Results: The developments allow expansion of the previous single-slice CEST MRI to a 3D whole-kidney coverage. Impact: CEST-MRI for renal assessment will provide valuable information on kidney health and function, adding to existing multiparameteric MRI protocols, to serve as a molecular-level assessment of diseases, such as differentiation of renal cancers and acute renal failure. |
| 4461.
 | 137 | Whole-cerebrum guanidino and amide CEST mapping at 3T by 3D EPI GRE and 3D stack-of-spiral GRE acquisitions Kexin Wang1,2, Licheng Ju2, Yulu Song3, Kevin Xie2, Claire Liu2, Anna Li2, Dan Zhu2,3, Feng Xu2,3, Guanshu Liu2,3, Hye-Young Heo2,3, Nirbhay Narayan Yadav2,3, Georg Oeltzschner2,3, Richard A.E. Edden2,3, Qin Qin2,3, Lindsay Blair4, David Olayinka Kamson4, and Jiadi Xu2
1Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, MD, United States Keywords: CEST / APT / NOE, CEST & MT Motivation: We are driven by the critical need to efficiently map guanidino and amide CEST in the human brain at 3T, enabling the investigation of brain creatine and protein while adhering to clinical scan time constraints. Goal(s): Our aim is to validate the efficacy of 3D EPI GRE and 3D stack-of-spiral (3DSOS) GRE techniques for rapid guanidino and amide CEST mapping at 3T. Approach: We optimized saturation parameters, conducted a comparative analysis of SNR and reproducibility, and demonstrated 3DSOS in a low-grade glioma patient. Results: Both techniques yielded similar CEST signal intensities, with 3DSOS showing superior reproducibility. Impact: While 3DEPI and 3DSOS yielded similar signal intensity in whole-cerebrum guanidino and amide CEST mappings at 3T, the latter is recommended for clinical application with its enhanced reproducibility and showed an increase of guanidino CEST in the tumor. |
| 4462.
 | 138 | Periodically Rotated Spiral Sampling (PRSS) and Multi-offset Transformer Reconstruction (MoTR) for CEST MRI Huabing LIU1,2,3, Yang LIU1, Abdul-Mojeed Olabisi ILYAS2, Jianpan HUANG4, Dinggang SHEN2,3,5,6, and Kannie W.Y. CHAN1,2,7
1Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China, 2Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China, 3School of Biomedical Engineering & State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai, China, 4Department of Diagnostic Radiology, University of Hong Kong, Hong Kong, China, 5Shanghai United Imaging Intelligence Co., Ltd., Shanghai, China, 6Shanghai Clinical Research and Trial Center, Shanghai, China, 7Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins Medicine, Baltimore, MD, United States Keywords: Image Reconstruction, CEST & MT, Spiral Sampling Motivation: CEST MRI is often limited in its application due to its time-consuming nature. Also, multiple saturation frequency offsets are required to accurately measure CEST effects. Goal(s): Accelerate CEST imaging by undersampling k-space of each frequency offset below Nyquist rate. Approach: Periodically rotated spiral sampling (PRSS) is proposed to make adjacent offsets capture different k-space subregions. Besides, a multi-offset transformer reconstruction (MoTR) network is further presented to fuse complementary information from multiple offsets. Results: Compared to fully-sampled images, reconstructed images using our method can achieve an average SSIM/MAE of 0.9899/0.0032, resulting a coefficient R value of 0.93/0.95 in terms of CEST signals at -3.5ppm/+3.5ppm. Impact: Our method can realize 4× acceleration of CEST imaging without sacrificing down-stream CEST analysis performance. Besides, our method has the potential to work on MRI scanner for CEST acceleration, which can further expand the application of CEST MRI. |
| 4463.
 | 139 | Obtaining exchange rate maps using Multitasking SS-CEST Karandeep Cheema1,2, Dante Rigo De Righi2, Chushu Shen1,2, Anthony Christodoulou1, Yibin Xie2, and Debiao Li1,2
1Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA, United States, 2Biomedical Imaging Research Institute, Cedars Sinai Medical Center, Los Angeles, CA, United States Keywords: Image Reconstruction, CEST & MT Motivation: To make qCEST clinically feasible by reducing the imaging time Goal(s): Multitasking steady-state (SS) approach was used to get 3D volume acquisition that reduced the imaging time per slice by a factor of 22 as compared to conventional qCEST. Approach: 6 Yucatan minipigs were scanned at four time points post interverbal disk injury. The injury was done at the lower three lumbar discs. Conventional 2D qCEST and 3D Multitasking steady state CEST were performed. Results: Scan time for conventional qCEST is 24 minutes/slice while the imaging time for Multitasking SS qCEST is 36 minutes for 32 slices, representing a factor of 22 improvement. Impact: This study represents the initial step in validating an accelerated
qCEST using Multitasking. The development of MRI-based pain assessment biomarkers in
this model is crucial for advancing our understanding and treatment of lower
back pain. |
| 4464.
 | 140 | Challenges for in-vivo hepatic GlycoNOE on human subjects at 7T Simone Poli1,2, Angeline Laura Buser3, David Herzig3, Lia Bally3, and Roland Kreis1,2
1Magnetic Resonance Methodology, Institute of Diagnostic and Interventional Neuroradiology, University of Bern, Bern, Switzerland, Bern, Switzerland, 2Translational Imaging Center, Sitem-insel, Bern, Switzerland, Bern, Switzerland, 3Insel Hospital, University Hospital Bern, Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism UDEM, Bern, Switzerland, Bern, Switzerland Keywords: CEST / APT / NOE, Spectroscopy, 13C-MRS, metabolism, validation, 7T, human Motivation: The GlycoNOE technique promises advantages compared to GlycoCEST and spectroscopic methods for fast non-invasive determination of hepatic glycogen content on standard MRI systems. Goal(s): Establish a robust glycoNOE technique at 7T for hepatic glycogen quantification in humans. Approach: A single-voxel MRS technique was combined with CEST modules and tested in vitro and in human subjects together with standard 13C-MRS. Results: The method gave excellent results in vitro, but in vivo the failure rate was substantial and shows that further refinements of the method are needed to provide robust measurements of hepatic glycogen in human subjects, especially in pathological conditions. Impact: The GlycoNOE technique promises advantages compared to GlycoCEST and
spectroscopic methods for determining hepatic glycogen content in vivo. Lack of
robustness as implemented for a combined CEST-spectroscopy technique hinders
its use in humans. |
| 4465.
 | 141 | Comparison of fast quantitative magnetization transfer imaging methods on a 1.5 T MR-Linac Brandon T. T. Tran1,2, Liam S. P. Lawrence1,2, Rachel W. Chan2, James Stewart3, Mark Ruschin3, Aimee Theriault3, Jay Detsky3, Sten Myrehaug3, Pejman J. Maralani4,5, Chia-Lin Tseng3, Hany Soliman3, Arjun Sahgal3, and Angus Z. Lau1,2
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Physical Sciences, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 3Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 4Medical Imaging, University of Toronto, Toronto, ON, Canada, 5Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada Keywords: Magnetization Transfer, Magnetization transfer, MR-Linac Motivation: Quantitative magnetization transfer (qMT) could guide radiotherapy on MRI-linear accelerators (MR-Linacs), but limited scan time requires a fast sequence. Fast 3D qMT is possible with balanced steady-state free precession (bSSFP) or echo-planar imaging (EPI), but which method is superior is unclear. Goal(s): Our goal was to determine whether bSSFP or EPI qMT on a 1.5T MR-Linac was best for imaging glioblastoma patients. Approach: Eight patients were scanned using both methods. Repeatability in normal tissue and magnitude of tumor changes were compared. Results: A 2 minute 20 second EPI qMT scan was more repeatable than bSSFP qMT and detected greater tumor changes. Impact: The improvement in quantitative
magnetization transfer acquisition speed through using 3D EPI enables
integration into MR-Linac radiotherapy workflows, an unmet need as qMT can
detect white matter changes which could be used to assess tumor response during
treatment. |
| 4466.
 | 142 | Advancing Z-Spectrum Analysis Protons (ZAP) Using Machine Learning with Random Forest Regression. Vadim Malis1 and Mitsue Miyazaki1
1Radiology, UC San Diego, La Jolla, CA, United States Keywords: Magnetization Transfer, CEST & MT, Z-Spectrum, AI Motivation: To overcome long scan times in MRI's Z-Spectrum Analysis Protons (ZAP), impairing its clinical utility and patient comfort. Goal(s): This study aimed to refine ZAP, targeting a reduction in scan duration while maintaining high accuracy in proton exchange measurements. Approach: We applied Random Forest Regression to identify key offset frequencies, focusing on the most informative data and potentially reducing the scanning time. Results: Our approach successfully reduced scan times without compromising accuracy. The RFR model’s predictions aligned closely with traditional ZAP methods, indicating that fewer offset frequencies are needed for reliable data interpretation. Impact: This study may allow for targeted anatomical and disease-specific imaging with reduced scan times, potentially improving diagnostic accuracy and patient experience, and facilitating quicker, more focused clinical decisions. |
| 4467.
 | 143 | A Simple Approach for Quantifying T1 and Macromolecular Proton Fraction from Rapid Inversion Recovery with 3D stack-of-spiral FLASH readout Zhen Hu1, Dan Zhu2,3, Yuguo Li2,3, Jiadi Xu2,3, and Qin Qin2,3
1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3The F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States Keywords: Magnetization Transfer, Magnetization transfer, T1, stack-of-spiral FLASH Motivation: Simultaneous Quantification of T1 and macromolecular proton fraction (fm) is desired but current methods are time consuming. Goal(s): To develop an approach for quantitative mapping of both apparent T1 and fM from inversion recovery (IR) curves. Approach: IR curves with efficient 3D stack-of-spiral FLASH readout were fitted with a monoexponential function, extracting both the apparent T1 and the inversion degree with the latter to determine fm. This method was evaluated through theory, simulation, phantom, and brain experiments. Results: This study demonstrated a simple and rapid approach for 3D mapping of both apparent T1 and fm. Impact: A simple and rapid approach for quantitative mapping of both apparent T1 and macromolecular proton fraction (fm) will help understanding the T1 contrast mechanism and facilitate developing pathological biomarkers for various clinical applications. |
| 4468.
 | 144 | Investigating the feasibility of reverse cross polarization for the development of a new myelin detection technique in MRI Alex Ensworth1,2, Cariad-Arianna Knight1, Piotr Kozlowski1,2,3,4, Cornelia Laule1,2,3,5, Alex L. MacKay1,3,4, and Carl A. Michal1
1Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, 2International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada, 3Radiology, University of British Columbia, Vancouver, BC, Canada, 4UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada, 5Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada Keywords: Non-Proton, Non-Proton, myelin, spectroscopy, phosphorus, hydrogen, spinal cord, cross polarization, NMR, magnetization transfer, brain Motivation: The potential of phosphorous MRI to enhance in vivo myelin detection and improve neurodegenerative disease diagnosis inspired our project. However, the challenge lies in transferring the solid phosphorus signal to aqueous protons for MRI measurement. Goal(s): To demonstrate the feasibility of detecting an aqueous proton signal originating from myelin phosphorous, providing a proof of principle result. Approach: We employed gradients in solid-state NMR experiments to investigate signal transfer between aqueous proton signal originating from myelin phosphorous, incorporating encoding and decoding gradients. Results: While individual transfer steps were successful, the complete transfer experiment yielded an unexpected negative result, indicating that further investigation is needed. Impact: The successful transfer of signal from phosphorous in myelin to aqueous hydrogen would lead to a new method for direct myelin detection. This could potentially offer earlier and more direct measurements of demyelination, benefiting those with neurodegenerative diseases. |