Purpose: Prototype phantoms were designed, constructed, and characterized for the purpose of calibrating ultralow field magnetic resonance imaging (ULF MRI) systems. The phantoms were designed to measure spatial resolution and to quantify sensitivity to systematic variation of proton density and relaxation time, T1 .
Methods: The phantoms were characterized first with conventional magnetic resonance scanners at 1.5 and 3 T, and subsequently with a prototype ULF MRI scanner between 107 and 128 μT .
Results: The ULF system demonstrated a 2-mm spatial resolution and, using T1 measurements, distinguished aqueous solutions of MnCl2 differing by 20 μM [Mn(2+) ].
Conclusion: The prototype phantoms proved well-matched to ULF MRI applications, and allowed direct comparison of the performance of ULF and clinical systems.
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http://dx.doi.org/10.1002/mrm.25060 | DOI Listing |
Gels
December 2024
Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Russia.
Hydrogels have a wide range of medical applications, including use within implantable systems. However, when used in implants, their visibility under conventional medical imaging techniques is limited, creating safety risks for patients. In the current work, we assessed the possibility of enhancing hydrogels using Ln-based contrasting agents to facilitate their visualization in photon-counting computed tomography (PCCT).
View Article and Find Full Text PDFJ Xray Sci Technol
December 2024
Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA.
Background And Objective: Optimization based image reconstruction algorithm is an advanced algorithm in medical imaging. However, the corresponding solving algorithm is challenging because the model is usually large-scale and non-smooth. This work aims to devise a simple and convergent solver for optimization model.
View Article and Find Full Text PDFJ Appl Clin Med Phys
December 2024
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, West Java, Indonesia.
Purpose: The goal of this study was to assess the feasibility of a cost-effective prototype of a laser-based respiratory motion detection system utilizing a Leuze LDS for breath monitoring through calibration and volunteer tests.
Methods: This study was performed using the Anzai AZ-773 V and computerized imaging reference systems (CIRS) motion phantoms for calibration tests. The calibration of the laser-based respiratory motion detection system involved spatial accuracy testing, amplitude calibration, and temporal accuracy.
Quant Imaging Med Surg
December 2024
Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, USA.
Background: Low-field open magnetic resonance imaging (MRI) systems, typically operating at magnetic field strengths below 1 Tesla, has greatly expanded the accessibility of MRI technology to meet a wide range of patient needs. However, the inherent challenges of low-field MRI, such as limited signal-to-noise ratios and limited availability of dedicated radiofrequency (RF) coils, have prompted the need for innovative coil designs that can improve imaging quality and diagnostic capabilities. In this work, we introduce a multimodal axial array resonator and its implementation in a volume coil, or referred to as a coupled stack-up volume coil, to address these challenges in low-field open MRI.
View Article and Find Full Text PDFInt J Med Robot
December 2024
Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
Background: In-bore MRI prostate biopsy offers improved visualisation and detection of significant prostate cancer; however, it is not widely practiced in cancer diagnosis due to its associated costs.
Methods: This work introduces the first prototype towards a 7-degrees-of-freedom (DOF) MRI-conditional piezoelectrically actuated robotic system for transperineal prostate biopsy. The robot enables needle insertions in the desired trajectories.
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