ISSN# 1545-4428 | Published date: 19 April, 2024
You must be logged in to view entire program, abstracts, and syllabi
At-A-Glance Session Detail
   
Acquisition Strategies II
Digital Poster
Acquisition & Reconstruction
Wednesday, 08 May 2024
Exhibition Hall (Hall 403)
08:15 -  09:15
Session Number: D-04
No CME/CE Credit

Computer #
3234.
1A novel diffusion MRI acquisition scheme for optimal orientation sampling and susceptibility distortion correction at 7T
Antoine Legouhy1, Martina F Callaghan2,3, Hui Zhang1, and David L Thomas2
1CMIC, University College London, London, United Kingdom, 2UCL Queen Square Institute of Neurology, University College London, London, United Kingdom, 3Imaging Neuroscience, University College London, London, United Kingdom

Keywords: Data Acquisition, Diffusion/other diffusion imaging techniques, Distortion correction

Motivation: 7T provides higher SNR compared to clinical field strengths, but susceptibility-induced distortion compromises diffusion imaging at 7T. Current methods to accurately correct distortion require doubling of scan time.

Goal(s): Develop an efficient acquisition scheme to enable distortion correction of multi-direction diffusion images without increased scan time.

Approach: Two ‘half-density’ acquisitions with opposing phase-encoding directions are collected, such that their gradient orientations uniformly sub-sample the sphere in a complementary manner. Spherical harmonics are used to interpolate image pairs for distortion correction.

Results: The proposed method provides distortion correction comparable to the full blip-up/blip-down approach, in half the acquisition time, while retaining the orientation density.

Impact: As the clinical benefits of 7T become established, it is crucial for all sequence types to be available for use. The methods proposed here enable advanced distortion-corrected diffusion imaging to be routinely and efficiently included in 7T imaging protocols.

3235.
2Contactless Cardiac Triggering Using Camera PPG in Cardiac MR
Steffen Weiss1, Julien Sénégas1, Christian Stehning2, Bert den Brinker3, Krelis Blom4, Annette Kok4, Cecilia Possanzini4, Jouke Smink4, Rudolf Springorum4, Pradhayini Ramamurthy4, and Jan Hendrik Wuelbern1
1Research Laboratories Hamburg, Philips GmbH Innovative Technologies, Hamburg, Germany, 2Philips Healthcare, Hamburg, Germany, 3Digital Standardization & Licensing Research, Philips, Eindhoven, Netherlands, 4Philips Healthcare, Best, Netherlands

Keywords: Data Acquisition, Heart, cardiac triggering

Motivation: Contactless cardiac triggering makes cardiac and cardiovascular MRI (cMRI) more accessible by improving patient comfort, reducing complexity, facilitating swift workflow, and increasing patient throughput.

Goal(s): In this work we demonstrate feasibility of contactless cardiac trigger detection using an in-bore camera in two routine cMRI sequences.

Approach: Building on an existing in-bore camera hardware we developed a cardiac trigger detection method for cMRI that extracts a remote photoplethysmography (rPPG) signal acquired at the patient’s forehead. The quality of the acquired MR images is compared with ECG triggering.

Results: rPPG and ECG triggering delivered comparable image quality in the majority of study volunteers.

Impact: The presented work provides evidence that cMRI is feasible with contactless, camera-based cardiac signal detection. The proposed method allows cMRI without placement of ECG electrodes, thus increasing accessibility of cardiac MR.

3236.
3Ultra-fast SWI using 3D-EPI and CAIPIRINHA: a feasibility study at 3-tesla
Sreekanth Madhusoodhanan Nair1, Nader Binesh2, Jin Jin3, Fei Han4, Elaina Gombos1, Brian Renner1, Mustafa Subhi1, Omar Al-Louzi1, Marwa Kaisey1, Nancy L Sicotte1, Debiao Li5, Marcel Maya2, and Pascal Sati1,5
1Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 3Siemens Healthcare Pty Ltd, Brisbane, Australia, 4Siemens Medical Solutions, Los Angeles, CA, United States, 5Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States

Keywords: Data Acquisition, Data Acquisition

Motivation: Conventional gradient echo SWI has a slow acquisition speed, thus limiting the minimal scan time achievable. However, accelerated 3D-EPI sequence can perform fast MR acquisition.

Goal(s): In this study, we evaluated the feasibility of SWI-EPI to generate ultra-fast susceptibility weighted images.

Approach: SWI-EPI combines a 3D (muti-shot) EPI sequence with CAIPIRINHA acceleration to significantly reduce the scan time.

Results: A significant reduction in scan time (up to 70%) was achieved with similar image quality and without any apparent artefacts, thus confirming the feasibility of ultra-fast SWI for future clinical neuro-applications at 3T.

Impact: This study demonstrates the feasibility of ultra-fast SWI-EPI at 3T.

3237.
4Practical sampling strategies for volumetric cardiac real-time MRI using stack-of-spirals at 0.55T
Prakash Kumar1, Rajiv Ramasawmy2, Ahsan Javed2, Ye Tian1, Adrienne Campbell-Washburn2, and Krishna S. Nayak1
1Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, United States, 2Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States

Keywords: Data Acquisition, Data Acquisition, Low-field MRI, Acquisition Methods, Cardiovascular

Motivation: Volumetric real-time MRI is desirable to accurately characterize beat-to-beat cardiac function in patients with arrythmia or heart failure.

Goal(s): To identify practical data sampling strategies for volumetric real-time MRI and evaluate cardiac volume measurements against gated reference scans.

Approach: We focus on stack-of-spirals bSSFP at 0.55T. We use simulations and in-vivo experiments to compare three sampling strategies that minimize eddy currents.

Results: A Gaussian distribution of the stack-of-spirals was found to provide the best real-time image quality and most accurate LV volumes, with under-estimation of end-diastolic volume by 7.44% and over-estimation of end-systolic volume by 18.33%.

Impact: Beat-to-beat cardiac function is important to measure in the context of arrhythmia, cardiac stress testing and in interventional MRI, where real-time volumetric coverage will facilitate assessment and monitoring of cardiac function.

3238.
5Spiral Time Resolved Imaging (SPTI)
Xiaoxi Liu1, Peder E.Z. Larson1, Yan Li1, Duan Xu1, and Di Cui1
1Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States

Keywords: Data Acquisition, Quantitative Imaging

Motivation: Spiral is the most efficient k-space coverage strategies in current MR gradient systems with robustness to motion and flow, but the implementation of long spiral trajectories keeps challenging due to accumulated off resonance effect and local susceptibility.

Goal(s): SPTI is proposed for artifact- and distortion-free spiral imaging and quantification.

Approach: Modified segmented spiral readout and subspace reconstruction were performed in SPTI technique.

Results: SPTI sequence was validated in a phantom study and feasibility was evaluated on a brain volunteer. In human study, SPTI method showed consistent results with MRF-EPTI on quantitative mapping, including PD, T1, T2 and T2*.

Impact: SPTI method can simultaneously quantify PD, T1, T2 and T2* mapping and is potential to expand to other body regions, especially in the liver and cardiac MRI.

3239.
6Accelerated Diffusion-Weighted MRI at 7T: Joint Reconstruction for Shift-Encoded Navigated Interleaved Echo Planar Imaging (JETS-NAViEPI)
Zhengguo Tan1, Patrick Liebig2, Robin Heidemann2, Frederik Laun3, and Florian Knoll1
1Artificial Intelligence in Biomedical Engineering, University of Erlangen-Nuremberg, Erlangen, Germany, 2Siemens Healthcare GmbH, Erlangen, Germany, 3University Hospital Erlangen, University of Erlangen-Nuremberg, Erlangen, Germany

Keywords: Data Acquisition, Diffusion/other diffusion imaging techniques

Motivation: Diffusion-weighted MRI suffers from limited spatial resolution, residual geometric distortion, and long acquisition.

Goal(s): To develop high spatial-angular-temporal resolution DW-MRI at 7T.

Approach: We developed ky-shift encoding and navigated interleaved EPI (NAViEPI) with consistent echo spacing, enabling efficient sampling and minimal distortion mismatch between echoes. We developed joint reconstruction with locally low-rank regularization, encompassing multi-band slices and multiple diffusion directions.

Results: We achieved (1) whole brain 3-scan trace acquisition at a resolution of 0.5 x 0.5 x 2.0 mm3 and 98 seconds, and (2) 3-shell 126 diffusion encodings with 1.0 mm isotropic resolution and 22 minutes scan time.

Impact: JETS-NAViEPI enables accelerated submillimeter resolution in vivo brain DW-MRI at 7T, offering both clinically relevant 3-scan trace and neuroscientific DTI protocols.

3240.
7Novel Sampling Schemes of Spin-locking Times to Improve Reproducibility of Quantitative 3D T1rho Mapping
Sandeep Panwar Jogi1, Qi Peng2, Ramin Jafari3, Ricardo Otazo1,4, and Can Wu1
1Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2Department of Radiology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, United States, 3MR Clinical Science, Philips Healthcare, Cambridge, MA, United States, 4Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States

Keywords: Data Acquisition, Quantitative Imaging, T1rho, Reproducibility, TSLs Sampling, Magnetization Preparation

Motivation: Reproducibility of T1rho measurements is crucial for longitudinal studies, as highly reproducible measurements are needed to detect treatment-induced changes in tissue properties. 

Goal(s): To evaluate two novel sampling schemes of spin-locking times (TSLs) to improve the reproducibility of T1rho quantification in inhomogeneous fields (B1/B0) compared to previously reported TSL-sampling schemes.

Approach: T1rho sequences with three different T1rho preparation modules and four TSL-sampling schemes were used for repeated scans of phantom and volunteers to evaluate reproducibility in each case.

Results: The proposed TSL-sampling schemes produced significantly better reproducibility (i.e., lower coefficient of variation) than the previously reported TSL-sampling schemes.
 

Impact: The proposed novel TSL-sampling schemes may enable T1rho relaxation parameter as a robust biomarker of imaging tissues with a slow-motional process despite B1/B0 inhomogeneities.

3241.
8Spiral cardiac cine imaging with water/fat separation
Tzu Cheng Chao1, Dinghui Wang1, James G Pipe2, and Tim Leiner1
1Department of Radiology, Mayo Clinic, Rochester, MN, United States, 2Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States

Keywords: Data Acquisition, Heart, spiral MRI, cardiac CINE, water/fat separation

Motivation: Water/fat separation can be helpful to better distinguish adipose tissue, blood and myocardium in a cardiac cine series. However, inclusion of a multi-echo acquisition in the conventional bSSFP sequence can introduce artifacts and reduce temporal efficiency.

Goal(s): To develop a fast and robust water/fat separation method for time-resolved cardiac cine imaging.

Approach: A spoiled gradient echo sequence with spiral acquisition is proposed to perform the cine acquisition with retrospectively cardiac gating.

Results: The image from the proposed method has shorter scan time, lower artifact level and lower RF deposition compared to a multi-echo bSSFP sequence.

Impact: We demonstrate the feasibility of spiral cardiac cine imaging with water/fat separation, enabling faster scanning while preserving adequate contrast among adipose tissue, blood and myocardium. This sequence also has low RF deposition with much lower SAR level for the patient.

3242.
9A novel sequence for Simultaneous imaging of cerebral Arteries and VEins (SAVE) based on velocity-selective arterial spin labeling
Lixin Liu1, Lili Wang1, Ying Hua Chu2, Jian Wang3, Hao Li1,4, He Wang1,4,5, and Zhensen Chen1,4
1Institute of Science and Technology for Brain-inspired Intelligence, Fudan University, Shanghai, China, 2MR Research Collaboration Team, Siemens Healthineers Ltd., Shanghai, China, 3The Department of Neurosurgery, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Changzhou Medical Center, Nanjing Medical University, Changzhou, China, 4Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China, 5Human Phenome Institute, Fudan University, Shanghai, China

Keywords: Data Acquisition, Vessels

Motivation: The conventional velocity-selective ASL-based (VSASL) MRA couldn’t separate arteries and veins unless additional module is used, which would cause long scan time. In addition, its acquisition efficiency is low since a long waiting time for blood refreshing.

Goal(s): To proposed a VSASL-based sequence for Simultaneous imaging of cerebral Arteries and VEins (SAVE). 

Approach: SAVE uses the waiting period between consecutive shots of VSASL MRA to acquire SWI data. VSASL MRA/MRV were obtained by subtracting Control images from Label images, while SWI images were averaged to increase SNR. 

Results: SAVE-VSASL MRA/MRV can well depict arteries and veins, and SAVE-SWI MRV could depict veins well. 

Impact: The novel sequence can obtain decent VSASL MRA/MRV and SWI MRV images. The combination of the VSASL MRA/MRV and SWI MRV in SAVE should allows separation of arteries and veins by post-processing, that may be useful in clinical settings. 

3243.
10Arbitrary Pulse Sequence Execution with Pulseq on Philips MRI Scanners
Imam Ahmed Shaik1, Qiang Liu1, Ryan Robison2,3, Yansong Zhao4, Maxim Zaitsev5, Jon-Fredrik Nielsen6, Yogesh Rathi1, Carl-Fredrik Westin7, Berkin Bilgic8,9, Borjan Gagoski10, Lipeng Ning1, Andrew Ellison11, Richard J Rushmore12, and William A Grissom13
1Brigham & Women's Hospital, Harvard Medical School, Boston, MA, United States, 2Philips, Nashville, TN, United States, 3Vanderbilt University Medical Center, Nashville, TN, United States, 4Philips Healthcare, Cambridge, MA, United States, 5Division of Medical Physics, Department of Radiology, University Medical Center Freiburg, Freiburg, Germany, 6fMRI Laboratory and Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, 7Department of Radiology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, United States, 8Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 9Department of Radiology, Harvard Medical School, Boston, MA, United States, 10Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States, 11Department of Radiology, Boston University Medical School, Boston, MA, United States, 12Department of Neurobiology, Boston University Medical School, Boston, MA, United States, 13Department of Biomedical Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, OH, United States

Keywords: Data Acquisition, Pulse Sequence Design

Motivation: To enable execution of open-source vendor-agnostic pulse sequences on Philips MRI scanners.

Goal(s): To develop a Pulseq interpreter for Philips scanner.

Approach: An intelligent Philips Pulseq interpreter, denoted "p2p" (Pulseq to Philips), was implemented in MATLAB. It converts Pulseq-generated .seq files into a format compatible with Philips sequence objects.

Results: The p2p interpreter was tested with sequences that included arbitrary gradient waveforms including custom spiral waveforms and crusher waveforms spelling out the words ‘Philips Pulseq’, GRE and DW-EPI scans evaluated in phantoms and in vivo.

Impact: Open-source Pulseq format sequences can be executed with minimal adaptations on Philips scanners. The p2p Pulseq Philips interpreter completes the set of interpreters required to implement harmonized pulse sequences across the three major vendor platforms.

3244.
11Accelerated multislice MRI with patterned excitation
Jacco A de Zwart1, Peter van Gelderen1, Yicun Wang1, and Jeff H Duyn1
1Advanced MRI section, LFMI/NINDS, National Institutes of Health, Bethesda, MD, United States

Keywords: Pulse Sequence Design, Pulse Sequence Design, accelerated imaging; displacement imaging; diffusion imaging

Motivation: Accelerate spin echo multi-slice MRI.

Goal(s): Combine echo dephasing and rephasing segments of different slices to reduce scan time.

Approach: Use a composite RF pulse to excite upcoming slices while refocusing signal from a current slice.

Results: Implementations at 3 T for spin echo based displacement encoding and spin echo and stimulated echo based DTI show 2-3 fold acceleration.

Impact: The proposed technique can accelerate 2D multi-slice imaging techniques that rely on multiple RF pulses per slice for signal generation and acquisition. It can be combined with simultaneous multi-slice and SENSE approaches for additional acceleration.

3245.
12Parallel contrast imaging from multi-echo SSFP
Coraline Beitone1, Mark Chiew2, Karla L Miller3, Neal K Bangerter1,4, and Peter J Lally1,5
1Department of Bioengineering, Imperial College London, London, United Kingdom, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom, 4Department of Electrical and Computer Engineering, Boise State University, Boise, ID, United States, 5Centre for Care Research and Technology, UK Dementia Research Institute, London, United Kingdom

Keywords: Pulse Sequence Design, Pulse Sequence Design

Motivation: Multi-echo steady-state acquisitions (Dual/Triple Echo Steady State) allow for the acquisition of multi-contrast images, but only in a sequential manner, which is time-inefficient, and requires substantial gradient spoiling to avoid banding artifacts.

Goal(s): Our goal was to introduce an alternative multi-contrast acquisition with parallel imaging capabilities.

Approach: By exploiting the effects of partial RF spoiling in Fluctuating Equilibrium MR (FEMR) imaging, we devised a novel acquisition strategy enabling simultaneous acquisition of aliased multi-contrast images and their subsequent reconstruction via SENSE.

Results: Implemented in 3D, our approach yields multiple images in one acquisition while providing flexibility over the acquired imaging contrasts.

Impact: This new acquisition strategy offers more time-efficient multi-contrast imaging while also reducing gradient requirements in comparison to existing approaches, creating new opportunities for rapid quantitative imaging experiments in healthy and diseased tissue.

3246.
13Novel method of Ultrashort TE 4D MR Angiography – Continuous Acquisition Variable TR (CAVTR) with View Sharing.
Haruyuki Fukuchi1,2, Toshiya Akatsu2, Hiroshi Kusahara2, Nao Takano3, Yutaka Ikenouchi2, Michimasa Suzuki2, Kohji Kamagata2, Akihiko Wada2, Osamu Abe1, and Shigeki Aoki2
1Department of Radiology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan, 2Department of Radiology, Juntendo University Graduate School of Medicine, Tokyo, Japan, 3Department of Radiology, Juntendo University Hospital, Tokyo, Japan

Keywords: Pulse Sequence Design, Arterial spin labelling, UTE, 4D MRA

Motivation: The conventional multi-phase Pulsed ASL UTE 4D MRA sometimes provides insufficient signal intensity to visualize hemodynamic flow characteristics in late phases.

Goal(s): Our goal is to improve the visibility of multi-phase Pulsed ASL UTE 4D MRA.

Approach: We developed a novel method, Continuous Acquisition Variable TR (CAVTR) UTE 4D MRA pulse sequence which utilizes continuously increasing TR. This new pulse sequence has less signal fluctuation and can avoid late phase signal reduction. We combined CAVTR with view sharing and improved late phase image quality without detriment to temporal resolution.

Results: This novel method can improve clinical usability of non-contrast ASL based UTE 4D-MRA.

Impact: The novel method, Continuous Acquisition Variable TR pulse sequence with View Sharing achieved both high temporal resolution and good visibility of arteries in late phases. This novel method can improve clinical usability of non-contrast ASL based UTE 4D-MRA.

3247.
14Pulse Sequence Design for Gradient Arrays in MRI
Mehmet Emin Öztürk1,2, Reza Babaloo1,2, and Ergin Atalar1,2
1Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center, Bilkent University, Ankara, Turkey

Keywords: Pulse Sequence Design, Pulse Sequence Design, Gradient Array

Motivation: Gradient arrays are superior compared to the conventional MR coils. However, there exists no pulse sequence design algorithm for the optimum use of the gradient array.

Goal(s): This work proposes a novel pulse sequence design schema for the optimum use of the gradient arrays

Approach: The algorithm utilizes a waveform optimization method. This method provides the shortest trapezoidal pulses with three inputs: the area to cover, starting and ending amplitudes.

Results: The algorithm is fit for any gradient array weight matrix with an arbitrary number of channels. It can provide the shortest timing values for any imaging plane while preserving the hardware limits.

Impact: There exists no pulse sequence design algorithm for the optimum use of the gradient array. We present a novel algorithm fit for any gradient array weighting with an arbitrary number of channels while providing the shortest timing values.

3248.
15Design of a power independent of finite number of slices (PIFINS) pulse for simultaneous multi-slice imaging
Jason A Reich1, Erin L MacMillan2, and Rebecca E Feldman1,3
1Department of Computer Science, Mathematics, Physics and Statistics, University of British Columbia, Kelowna, BC, Canada, 2UBC MRI Research, Department of Radiology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada, 3Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States

Keywords: Pulse Sequence Design, RF Pulse Design & Fields

Motivation: Simultaneous mutli-slice (SMS) techniques can reduce scan times. Power deposition from multiband pulses and outer slice signal from power independent of number of slices (PINS) pulses has hampered thoracic and cardiac SMS imaging.

Goal(s): To reduce power deposition in thoracic and cardiac SMS imaging, thereby reducing scan times and motion artifacts.

Approach: A power independent of finite number of slices (PIFINS) pulse was designed to excite any number of slices over a desired field of view with power deposition comparable to single-band pulse.

Results: The PIFINS pulse was used to simultaneously acquire 3 slices in a cylindrical ACR phantom.

Impact: Reducing scan time in thoracic and cardiac imaging reduces motion artifacts. Acceleration with simultaneous multi-slice has been hampered due to high power deposition. The new pulse presented here will enable SMS thoracic and cardiac imaging with reduced power deposition.

3249.
16High-Accuracy Ultra-short Inner-Volume Saturation Pulse for 3D Steady-State Imaging
Yongli He1, Rex Fung2, and Jon-Fredrik Nielsen2
1fMRI Laboratory and Applied Physics Program, University of Michigan-Ann Arbor, Ann Arbor, MI, United States, 2fMRI Laboratory and Biomedical Engineering, University of Michigan-Ann Arbor, Ann Arbor, MI, United States

Keywords: Pulse Sequence Design, Software Tools

Motivation: Spatially-tailored excitation is often favorable in MR applications where the region-of-interest only occupies a small portion of the whole FOV.

Goal(s): In this study, we sought to design an inner-volume saturation pulse for steady-state imaging.

Approach: We propose an extension to the AutoDiff tool by Luo et al. Here we use steady-state magnetization error as the design objective instead of one-time excitation error in the original design.

Results: Our proposed pulse design can excite spatially-selective patterns with ultra-short duration(~1.2ms) and high accuracy (error reduced by 50% compared to the original design).

Impact: Our pulse design tool enables highly accurate multi-dimensional spatially-tailored excitations with ultra-short pulses. Such pulses can be plugged into functional MRI sequences, and be played in clinical scenarios where ROI-specific excitations can mitigate motion artifacts and reduce image encoding time.