背景:在2017年批准临床使用后,超高场腹部磁共振成像(MRI)的早期研究已经证明了肝脏的可行性和诊断能力,肾,和7特斯拉的前列腺MRI。然而,场强提高到7特斯拉,不仅给腹部MRI带来了优势,也带来了相当大的挑战和缺点,主要源于增强的伪影和比吸收率的限制,等。此外,与幻影/动物研究相比,文献中关于人类研究的证据相对较少,这需要对迄今为止人类的证据进行调查并总结所有相关证据。
目的:为了全面概述当前关于腹部7TMRI临床的文献,强调当前的趋势,详细说明相关挑战,并提供了一套简洁的潜在解决方案。
方法:本系统评价遵循系统评价和荟萃分析指南的首选报告项目。PubMed搜索,利用医学主题词,如“7-Tesla”和器官特异性术语,是针对1985年1月1日至2023年7月25日之间发表的文章进行的。合格标准包括探索7TMRI对人体腹部器官成像的研究,涵盖各种研究类型(体内/离体,方法开发,评论/荟萃分析)。排除标准涉及动物研究和缺乏可提取数据的研究。研究选择涉及通过标题/摘要进行初始识别,随后是两位研究人员的全文回顾,通过讨论解决了差异。数据提取涵盖出版物详细信息,研究设计,人口,样本量,7TMRI协议,图像特征,端点,和结论。
结果:系统评价共纳入21项研究。临床7T腹部成像研究的分布显示主要集中在前列腺上(n=8),其次是肾脏(n=6)和肝胆系统(n=5)。对这些器官的研究,在胰腺中,在7T时表现出明显的优势。然而,与1.5T时的传统MRI相比,小肠研究没有显着改善。评估的大多数研究都来自德国(n=10),其次是荷兰(n=5),美国(n=5)奥地利(n=2),英国(n=1),意大利(n=1)。
结论:腹部临床MRI场强进一步增加至7T显示出很高的成像潜力,然而,限制也主要是由于相对于较低的场强的不均匀的射频(RF)激发场。因此,专用RF线圈元件和脉冲序列的进一步优化有望在高磁场强度下更好地优化临床成像。
BACKGROUND: After approval for clinical use in 2017 early investigations of ultra-high-field
abdominal magnetic resonance imaging (MRI) have demonstrated the feasibility as well as diagnostic capabilities of liver, kidney, and prostate MRI at 7-Tesla. However, the elevation of the field strength to 7-Tesla not only brought advantages to
abdominal MRI but also presented considerable challenges and drawbacks, primarily stemming from heightened artifacts and limitations in Specific Absorption Rate, etc. Furthermore, evidence in the literature is relatively scarce concerning human studies in comparison to phantom/animal studies which necessitates an investigation into the evidence so far in humans and summarizing all relevant evidence.
OBJECTIVE: To offer a comprehensive overview of current literature on clinical abdominal 7T MRI that emphasizes current trends, details relevant challenges, and provides a concise set of potential solutions.
METHODS: This systematic
review adheres to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A PubMed search, utilizing Medical Subject Headings terms such as \"7-Tesla\" and organ-specific terms, was conducted for articles published between January 1, 1985, and July 25, 2023. Eligibility criteria included studies exploring 7T MRI for imaging human abdominal organs, encompassing various study types (in-vivo/ex-vivo, method development, reviews/meta-analyses). Exclusion criteria involved animal studies and those lacking extractable data. Study selection involved initial identification via title/abstract, followed by a full-text
review by two researchers, with discrepancies resolved through discussion. Data extraction covered publication details, study design, population, sample size, 7T MRI protocol, image characteristics, endpoints, and conclusions.
RESULTS: The systematic
review included a total of 21 studies. The distribution of clinical 7T abdominal imaging studies revealed a predominant focus on the prostate (n = 8), followed by the kidney (n = 6) and the hepatobiliary system (n = 5). Studies on these organs, and in the pancreas, demonstrated clear advantages at 7T. However, small bowel studies showed no significant improvements compared to traditional MRI at 1.5T. The majority of studies evaluated originated from Germany (n = 10), followed by the Netherlands (n = 5), the United States (n = 5), Austria (n = 2), the United Kingdom (n = 1), and Italy (n = 1).
CONCLUSIONS: Further increase of abdominal clinical MRI field strength to 7T demonstrated high imaging potential, yet also limitations mainly due to the inhomogeneous radiofrequency (RF) excitation field relative to lower field strengths. Hence, further optimization of dedicated RF coil elements and pulse sequences are expected to better optimize clinical imaging at high magnetic field strength.