Purpose: Spiral readouts combine several favorable properties that promise superior net sensitivity for diffusion imaging. The purpose of this study is to verify the signal-to-noise ratio (SNR) benefit of spiral acquisition in comparison with current echo-planar imaging (EPI) schemes.
Methods: Diffusion-weighted in vivo brain data from three subjects were acquired with a single-shot spiral sequence and several variants of single-shot EPI, including full-Fourier and partial-Fourier readouts as well as different diffusion-encoding schemes. Image reconstruction was based on an expanded signal model including field dynamics obtained by concurrent field monitoring. The effective resolution of each sequence was matched to that of full-Fourier EPI with 1 mm nominal resolution. SNR maps were generated by determining the noise statistics of the raw data and analyzing the propagation of equivalent synthetic noise through image reconstruction. Using the same approach, maps of noise amplification due to parallel imaging (g-factor) were calculated for different acceleration factors.
Results: Relative to full-Fourier EPI at b = 0 s/mm , spiral acquisition yielded SNR gains of 42-88% and 40-89% in white and gray matter, respectively, depending on the diffusion-encoding scheme. Relative to partial-Fourier EPI, the gains were 36-44% and 34-42%. Spiral g-factor maps exhibited less spatial variation and lower maxima than their EPI counterparts.
Conclusion: Spiral readouts achieve significant SNR gains in the order of 40-80% over EPI in diffusion imaging at 3T. Combining systematic effects of shorter echo time, readout efficiency, and favorable g-factor behavior, similar benefits are expected across clinical and neurosciences uses of diffusion imaging.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/mrm.28554 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Development of a low-dose strategy for propagation-based imaging helical computed tomography (PBI-HCT): high image quality and reduced radiation dose.
Biomed Phys Eng Express
December 2024
Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada.
Article Synopsis
- Propagation-based imaging computed tomography (PBI-CT) is gaining popularity for visualizing low-density materials thanks to its high resolution and image contrast, but it poses radiation risks in live animal imaging due to high doses.
- This study integrates a deep learning method called Sparse2Noise with PBI-CT to significantly reduce radiation exposure (up to 90%) while preserving image quality, showing improved results over traditional low-dose imaging methods.
- The findings indicate that Sparse2Noise provides a better signal-to-noise ratio compared to two other advanced low-dose algorithms, enhancing the effectiveness of PBI-CT for biomedical applications.
NON-CARTESIAN SELF-SUPERVISED PHYSICS-DRIVEN DEEP LEARNING RECONSTRUCTION FOR HIGHLY-ACCELERATED MULTI-ECHO SPIRAL FMRI.
Proc IEEE Int Symp Biomed Imaging
May 2024
Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.
Functional MRI (fMRI) is an important tool for non-invasive studies of brain function. Over the past decade, multi-echo fMRI methods that sample multiple echo times has become popular with potential to improve quantification. While these acquisitions are typically performed with Cartesian trajectories, non-Cartesian trajectories, in particular spiral acquisitions, hold promise for denser sampling of echo times.
View Article and Find Full Text PDFSpiral cardiac quantitative susceptibility mapping for differential cardiac chamber oxygenation-Initial validation in relation to invasive blood sampling.
Magn Reson Med
December 2024
Department of Radiology, Weill Cornell Medicine, New York, New York, USA.
Purpose: To develop a breath-hold cardiac quantitative susceptibility mapping (QSM) sequence for noninvasive measurement of differential cardiac chamber blood oxygen saturation (ΔSO).
Methods: A non-gated three-dimensional stack-of-spirals QSM sequence was implemented to continuously sample the data throughout the cardiac cycle. Measurements of ΔSO between the right and left heart chamber obtained by the proposed sequence and a previously validated navigator Cartesian QSM sequence were compared in three cohorts consisting of healthy volunteers, coronavirus disease 2019 survivors, and patients with pulmonary hypertension.
Magnetic resonance acoustic radiation force imaging (MR-ARFI) is an exceptionally promising technique to non-invasively confirm targeting accuracy and estimate exposure of low-intensity transcranial focused ultrasound stimulation. MR-ARFI uses magnetic field motion encoding gradients to visualize the MR phase changes generated by microscopic displacements at the ultrasound focus. Implementing MR-ARFI in the human central nervous system has been hindered by 1) phase distortion caused by subject motion, and 2) insufficient signal-to-noise ratio at low (<1.
View Article and Find Full Text PDFAirborne electro-optical countermeasure systems necessitate designs that are both lightweight and miniaturized. This study examines a single-detector composite-axis system that integrates a large-stroke, large-aperture two-axis mirror for coarse tracking tasks and a piezoelectric fast-steering mirror for fine tracking adjustments. Addressing the system's initial pointing and spiral scanning challenges, the study derives dynamic target-pointing equations using coordinate transformation and optical geometry.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!