Investigating Local Receive Arrays in tcMRgFUS System and Their Influence by Passive Antennas: A Simulation Study.
Authors: Lu M, Yan X
Transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) revolutionizes non-invasive therapy by combining MRI and high-intensity focused ultrasound for precise thermal treatment. MRI scans play an essential role during tcMRgFUS treatment in that they are used to localize the target and monitor temperature. Using the body coil for MRI introduces imaging challenges, notably extremely low signal-to-noise ratio (SNR) and a distinct dark band in 3 Tesla brain images. This study explores the impact of diverse local receive coils on SNR and parallel imaging capabilities in tcMRgFUS. Simulation results underscore the significant SNR enhancement, especially with helmet-shaped coils, crucial for capturing signals from the head's top and sides. Additionally, the study delves into integrating passive antennas to address the dark band issue, revealing a combined improvement in SNR and transmit field recovery. The study demonstrates that even a coil array outside the water bath can enhance SNR. This work offers critical insights into optimizing the imaging quality, improving temperature mapping accuracy, and recovering the transmit field in tcMRgFUS technology, holding potential for refined treatment visualization, targeting precision, and real-time monitoring.
Introduction
Purpose
Thermal ablation
Study Objective
To evaluate the effects of various local receive coil designs and passive antennas on signal-to-noise ratio, parallel imaging performance, and transmit field recovery in transcranial MR-guided focused ultrasound (tcMRgFUS).
Animal model / Human subject
Human (Homo sapiens; vendor-provided anatomical model), strain: N/A, age: None, sex: None
Disease model
Healthy
MRI or image guidance method
MRI-guided (transcranial MR-guided focused ultrasound, tcMRgFUS)
Outcomes and Safety
Summary of Outcomes
Using local receive coils markedly improved MRI performance for tcMRgFUS— a close‑fitting dual‑row 12‑channel helmet coil gave the largest central SNR gain (~12× vs the body coil), with 6‑ch submerged ~6×, 2‑ch submerged ~4.2×, and an outside 6‑ch ~2.7×; adding passive “Propeller Beanie” antennas increased central SNR of single‑row arrays by ~15–24% and helped recover the transmit field, while causing a small (~9%) SNR drop and higher g‑factor in the dual‑row 12‑ch array due to coupling.
Safety-related matter
The paper does not report any safety issues or adverse effects; no adverse events or patient safety concerns are mentioned in the text.
Brain Region
Ultrasound Parameters
Ultrasound instrument
Insightec tcMRgFUS (Insightec); transducer: 30-cm diameter hemispherical transducer bowl
Focal Characteristics
Focal depth: None; Focal length: None; Aperture size: 30 cm diameter
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