Perera Molligoda Arachchige Arosh S, Teixeira de Castro Gonçalves Ortega Ana Claudia, Catapano Federica, Politi Letterio S, Hoff Michael N
Faculty of Medicine, Humanitas University, Pieve Emanuele 20072, Milan, Italy.
Department of Biomedical Sciences, Humanitas University, Pieve Emanuele 20072, Milan, Italy.
World J Radiol. 2024 Jan 28;16(1):20-31. doi: 10.4329/wjr.v16.i1.20.
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, 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.
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.
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 (/, method development, reviews/meta-analyses). Exclusion criteria involved animal studies and those lacking extractable data. Study selection involved initial identification 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.
The systematic review included a total of 21 studies. The distribution of clinical 7T abdominal imaging studies revealed a predominant focus on the prostate ( = 8), followed by the kidney ( = 6) and the hepatobiliary system ( = 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 ( = 10), followed by the Netherlands ( = 5), the United States ( = 5), Austria ( = 2), the United Kingdom ( = 1), and Italy ( = 1).
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.
2017年超高场腹部磁共振成像（MRI）获批临床应用后，早期研究已证明7特斯拉下肝脏、肾脏和前列腺MRI的可行性及诊断能力。然而，场强提升至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，主要源于伪影增加和比吸收率限制。此外，与体模/动物研究相比，关于人体研究的文献证据相对较少，因此有必要对目前人体研究的证据进行调查并总结所有相关证据。
全面概述当前关于临床腹部7T MRI的文献，强调当前趋势，详述相关挑战，并提供一套简洁的潜在解决方案。
本系统评价遵循系统评价和Meta分析的首选报告项目指南。利用“7特斯拉”等医学主题词和器官特异性术语在PubMed上搜索1985年1月1日至2023年7月25日发表的文章。纳入标准包括探索7T MRI用于人体腹部器官成像的研究，涵盖各种研究类型（/、方法开发、综述/Meta分析）。排除标准包括动物研究和缺乏可提取数据的研究。研究选择包括首先通过标题/摘要进行初步识别，然后由两名研究人员进行全文审查，分歧通过讨论解决。数据提取涵盖发表细节、研究设计、人群、样本量、7T MRI方案、图像特征、终点和结论。
该系统评价共纳入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（=8），其次是肾脏（=6）和肝胆系统（=5）。对这些器官以及胰腺的研究表明，7T具有明显优势。然而，与1.5T的传统MRI相比，小肠研究未显示出显著改善。大多数评估的研究来自德国（=10），其次是荷兰（=5）、美国（=5）、奥地利（=2）、英国（=1）和意大利（=1）。
腹部临床MRI场强进一步提高到7T显示出高成像潜力，但也存在局限性，主要是相对于较低场强而言，射频（RF）激发场不均匀。因此，预计进一步优化专用RF线圈元件和脉冲序列将更好地优化高磁场强度下的临床成像。
