Improvement in Intraoperative Image Quality in Transcranial Magnetic Resonance-Guided Focused Ultrasound Surgery Using Transmitter Gain Adjustment.

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2023-01-01 Epub Date: 2023-06-28 DOI:10.1159/000531009

Hiroki Hori, Yusuke Yamada, Masayuki Nakano, Takahiro Ouchi, Masahito Takasaki, Ken Iijima, Takaomi Taira, Keiichi Abe, Hirokazu Iwamuro

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引用次数: 0

Abstract

Introduction: Transcranial magnetic resonance-guided focused ultrasound surgery (TcMRgFUS) has the advantage of allowing immediate evaluation of therapeutic effects after each sonication and intraoperative magnetic resonance imaging (MRI) to visualize the lesion. When the image shows that the lesion has missed the planned target and the therapeutic effects are insufficient, the target of the subsequent ablation can be finely adjusted based on the image. The precision of this adjustment is determined by the image quality. However, the current intraoperative image quality with a 3.0T MRI system is insufficient for precisely detecting the lesion. Thus, we developed and validated a method for improving intraoperative image quality.

Methods: Because intraoperative image quality is affected by transmitter gain (TG), we acquired T2-weighted images (T2WIs) with two types of TG: the automatically adjusted TG (auto TG) and the manually adjusted TG (manual TG). To evaluate the character of images with 2 TGs, the actual flip angle (FA), the image uniformity, and the signal-to-noise ratio (SNR) were measured using a phantom. Then, to assess the quality of intraoperative images, T2WIs with both TGs were acquired during TcMRgFUS for 5 patients. The contrast-to-noise ratio (CNR) of the lesion was retrospectively estimated.

Results: The images of the phantom with the auto TG showed substantial variations between the preset and actual FAs (p < 0.01), whereas on the images with the manual TG, there were no variations between the two FAs (p > 0.05). The total image uniformity was considerably lower with the manual TG than with the auto TG (p < 0.01), indicating that the image's signal values with the manual TG were more uniform. The manual TG produced significantly higher SNRs than the auto TG (p < 0.01). In the clinical study, the lesions were clearly detected in intraoperative images with the manual TG, but they were difficult to identify in images with the auto TG. The CNR of lesions in images with manual TG was considerably higher than in images with auto TG (p < 0.01).

Conclusion: Regarding intraoperative T2WIs using a 3.0T MRI system during TcMRgFUS, the manual TG method improved image quality and delineated the ablative lesion more clearly than the current method with auto TG.

Abstract Image

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利用发射器增益调整改善经颅磁共振引导聚焦超声手术中的术中图像质量。

引言：经颅磁共振引导聚焦超声手术（TcMRgFUS）的优点是可以在每次超声处理后立即评估治疗效果，并在术中进行磁共振成像（MRI）以显示病变。当图像显示病变已经错过了计划目标并且治疗效果不足时，可以基于图像精细地调整后续消融的目标。这种调整的精度由图像质量决定。然而，目前3.0T MRI系统的术中图像质量不足以精确检测病变。因此，我们开发并验证了一种提高术中图像质量的方法。方法：由于术中图像质量受发射增益（TG）的影响，我们采集了两种类型的TG的T2加权图像（T2WIs）：自动调整TG（auto-TG）和手动调整TG（manual-TG）。为了评估具有2个TG的图像的特性，使用体模测量实际翻转角（FA）、图像均匀性和信噪比（SNR）。然后，为了评估术中图像的质量，在5名患者的TcMRgFUS期间采集了具有两种TG的T2WI。对病变的对比噪声比（CNR）进行了回顾性估计。结果：具有自动TG的体模的图像显示预设和实际FA之间存在显著差异（p＜0.01），而在具有手动TG的图像上，两个FA之间没有差异（p＞0.05）。手动TG的总图像均匀性显著低于自动TG（p＜0.05），表明具有手动TG的图像的信号值更加均匀。手动TG产生的SNR明显高于自动TG（p＜0.01）。在临床研究中，手动TG在术中图像中可以清楚地检测到病变，但在自动TG图像中很难识别。手动TG图像中病变的CNR显著高于自动TG图像（p＜0.01）。结论：在TcMRgFUS期间使用3.0T MRI系统的术中T2WI，手动TG方法比当前的自动TG方法提高了图像质量，更清楚地描绘了消融病变。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.