Aug 2026· Magnetic Resonance in Medicine· 0 citations· 39 references
Medicine
TL;DR
A gradient-recalled echo (GRE) sequence is presented alongside an image-based analysis for SNR estimation and QC of 13C coils, advancing the clinical translation of 13C MRS methodologies.
Abstract
Purpose
Due to the inherently low signal-to-noise ratio (SNR) domain for 13C imaging, optimal coil performance is essential to maximize data quality. Quality control (QC) for 13C coils employed in magnetic resonance spectroscopy (MRS) is of paramount importance. This study presents a gradient-recalled echo (GRE) sequence alongside an image-based analysis for SNR estimation and QC of 13C coils.
Methods
The proposed GRE sequence (slice selective RF pulse, slice thickness 100 mm, 16 averages, 64 × 64 matrix size, 400 × 400 mm FOV, 60 Hz/px BW, 50° FA, 80 ms TR, 14 ms TE, cartesian acquisition trajectory) was comprehensively evaluated on four clinical 3 T systems, across three sites and two vendors. Thirteen coils were evaluated, including multiple surface coils (transmit/receive and receive only) and volume coils for different body parts. The GRE sequence was compared with a previously described chemical shift imaging (CSI) technique for QC of 13C coils. The GRE sequence is widely available and built into all MR systems. In contrast, the CSI sequence is more specialized and is not available for all imaging systems.
Results
A Passing-Bablok regression and a Spearman correlation of 0.78 demonstrated good agreement of the two methods. The GRE approach offers reduced acquisition time and simplified analysis with SNR trends demonstrating reproducible coil performance across all sites and vendors.
Conclusion
This standardization aims to strengthen multi-center trials by ensuring data comparability and reliability, advancing the clinical translation of 13C MRS methodologies. The results and analysis pipeline is made publicly available to facilitate implementation and coil comparisons across institutions.
PURPOSE
To evaluate k-space acquisition strategies for magnetic resonance imaging (MRI) in a nonuniform B0 (NuBo) field-cycling system, focusing on image quality, scan-time efficiency, robustness to B0 inhomogeneity, and RF coil bandwidth constraints.
METHODS
Three acquisition strategies were compared: single-shot turbo spin echo (SS-TSE), multi-echo spin echo (MESE) with repeated phase encoding, and spin echo single-point imaging (SE-SPI) without applied readout (RO) gradients. Experiments were performed on an open, low-field, field-cycling MRI system using a nonuniform electromagnet. Imaging performance was assessed using a phantom and biological samples under matched total scan-time conditions. RF coils with wide- and narrow-bandwidth designs were evaluated to study sensitivity trade-offs. Retrospective k-space undersampling and compressed sensing reconstruction were applied to investigate potential scan-time reduction for all acquisition strategies.
RESULTS
SE-SPI consistently achieved larger full width at half maximum (FWHM) values than SS-TSE and MESE, indicating improved edge definition. Edge sharpness was higher along the RO (PE1) direction but comparable along the PE (PE2) direction. SS-TSE provided the fastest k-space acquisition and the highest central k-space SNR but exhibited increased blurring and bandwidth-related signal loss. MESE improved edge definition over SS-TSE while requiring additional polarization cycles. SE-SPI also showed greater robustness to compressed sensing undersampling.
CONCLUSION
SE-SPI provides a robust acquisition strategy for MRI in nonuniform B0 field-cycling systems by improving image fidelity, maintaining uniform signal intensity, enabling efficient use of high-Q RF coils, and supporting compressed sensing acceleration.
Y. Ha, Chenhao Sun, Anja Samardzija et al.· Magnetic Resonance in Medici...· 0 citations
CS-MPRAGE provides high-quality 3D images and reliable volume data with significantly reduced acquisition time and comparable image quality by comparing its scan time and image quality with standard MPRAGE.
This work presents an open-source, optimized solenoid head coil tailored for the 50 mT open-source scanner (OSII ONE v2.1), set the basis for a fully reliable and reproducible component for the open-source OSII ONE MRI scanner.
Umberto Zanovello, Julia Pfitzer, Ariane Ernst et al.· 1 citation
BACKGROUND
Access to MRI is limited by lengthy exam times and inefficient utilization. Focused protocols can reduce exam times, but workflow variability and inefficient room turnaround contribute to conservative scheduling with long exam slots.
PURPOSE
To develop and evaluate a high-throughput clinical MRI suite architecture and workflow, using an AI-prescribed free-breathing chemical shift-encoded (CSE) MRI exam to quantify liver proton density fat fraction (PDFF) in under 5 min of total MRI room time.
STUDY TYPE
Prospective.
SUBJECTS
24 healthy volunteers in two cohorts: 12 research staff (7 women/5 men; age 26.8 ± 5.8 years) and 12 community volunteers (6 women/6 men; age 41.3 ± 13.5 years).
FIELD STRENGTH/SEQUENCE
1.5 T; free-breathing 2D multi-echo gradient echo CSE-MRI.
ASSESSMENT
Each participant underwent three nonconsecutive CSE-MRI exams in a continuously queued workflow to characterize timing and PDFF repeatability. Workflow intervals were recorded from timestamped video review and image metadata. Staff cohort exams included two CSE-MRI acquisitions to assess within-exam repeatability, while community cohort exams included one to simulate clinical practice. Three radiologists (8/13/14 years of experience) independently evaluated AI-automated prescriptions for complete liver coverage and rated CSE-MRI image quality (five-point Likert scale).
STATISTICAL TESTS
Student's t-tests; Gwet's AC2; repeatability coefficients (RCs) with bootstrap 95% confidence intervals; Bland-Altman analysis. p < 0.05 was significant.
RESULTS
Diagnostic image quality was achieved in all 72 exams (median PDFF Likert score 5/5, inter-rater AC2 ≥ 0.86). Total MRI room times averaged 4:09 ± 0:14 min (staff) and 3:35 ± 0:34 min (community). Turnaround times averaged under 2 min, enabling throughput of 16.1 exams per hour in the community cohort. Automated prescription achieved complete liver coverage in all exams. PDFF RCs were 0.78% (staff within-exam), 0.99% (staff between-exam), and 1.21% (community between-exam) absolute PDFF.
DATA CONCLUSION
The proposed high-throughput MRI workflow achieved over 16 exams per hour with highly repeatable liver fat quantification, demonstrating a framework for improving MRI utilization and access.
EVIDENCE LEVEL
1.
STAGE OF TECHNICAL EFFICACY
2.
Garrett C Fullerton, Jiayi Tang, Jitka Starekova et al.· Journal of Magnetic Resonanc...· 1 citation
PURPOSE
To evaluate the clinical feasibility and quantitative performance of adaptive complex signal average (ACSA) diffusion-weighted imaging (DWI) in abdominal MRI and to compare ACSA DWI with conventional non-ACSA DWI in terms of signal intensity (SI), SNR, apparent diffusion coefficient (ADC), signal intensity difference ratio (SIDR), and lesion contrast across different numbers of excitations (NEX).
METHODS
This retrospective study included 82 patients who underwent free-breathing abdominal DWI on a 3T system between January and July 2025. ACSA DWI was reconstructed from the same raw data as non-ACSA DWI using a combination of adaptive averaging and complex-domain averaging. ROIs were placed in the liver, pancreas, left adrenal gland, and spinal muscles to measure SI, SNR, and ADC. SIDR and inter-lobar right-left (R-L) ratio in SI and ADC were calculated at NEX 2, 3, and 4. For 37 patients with non-cystic hepatic nodules, lesion SI, ADC, contrast ratio, and contrast-to-noise ratio (CNR) were assessed.
RESULTS
ACSA DWI significantly increased SI and SNR in motion-prone organs, including the lateral hepatic segment, pancreas, and left adrenal gland, at all NEX levels (P < 0.05). ADC values in abdominal parenchymal organs and hepatic nodules were lower with ACSA DWI, reflecting the noise-floor suppression and adaptive average effects. R-L SI and ADC ratios were significantly different and were closer to 1 in ACSA DWI, indicating improved hepatic signal homogeneity. Lesion SI, contrast ratio, and CNR were significantly higher with ACSA DWI, enhancing nodule conspicuity.
CONCLUSION
ACSA DWI improves signal uniformity, SNR, and lesion contrast while maintaining reasonable ADC quantification. Without prolonging scan time or modifying acquisition parameters, ACSA provides a robust, clinically feasible post-processing technique for enhancing both image quality and quantitative reliability in abdominal DWI.
Miwa Matsukuma, M. Tanabe, M. Higashi et al.· Magnetic Resonance in Medica...· 0 citations
Abstract Objectives To evaluate the feasibility and clinical utility of cardiovascular four-dimensional flow magnetic resonance imaging (4D Flow MRI) for multidirectional hemodynamic visualization and quantitative assessment. Methods This single-centre observational study included 30 cardiovascular MRI cases acquired at Huaqiao University Affiliated Strait Hospital using a Siemens MAGNETOM Skyra 3.0-T system with an 18-channel phased-array coil. Time-resolved three-dimensional velocity-encoded 4D Flow MRI was performed with retrospective electrocardiographic gating, respiratory compensation, and region-adjusted velocity encoding. Acquisition parameters included TR/TE 38.88/6.88 ms, flip angle 8°, matrix 256 × 256, field of view 300 mm, in-plane spatial resolution 1.4 × 1.4 mm, slice thickness 3 mm, and slice gap 0.6 mm. Preprocessing corrected background phase offsets, Maxwell terms, velocity aliasing, and noise artefacts. Results 4D Flow MRI enabled assessment of intracardiac shunting, pulmonary regurgitation, Fontan circulation, bicuspid aortic valve hemodynamics, aortic regurgitation, and atrioventricular valve dysfunction. Quantified parameters included pulmonary-to-systemic flow ratio, shunt volume, regurgitant fraction, peak velocity, pressure gradient, wall shear stress, vorticity, helicity, kinetic energy, turbulent kinetic energy, oscillatory shear index, and energy loss. Conclusions Cardiovascular 4D Flow MRI supports patient-specific hemodynamic assessment across complex cardiovascular conditions within a practical single-centre clinical workflow with retrospective quantification.
Yuguang Ye, Taisheng Zeng, Yusi Chen et al.· Biomedizinische Technik. Bio...· 0 citations
