Rofo 2020; 192(06): 537-548
DOI: 10.1055/a-1123-7944

Low-Field Magnetic Resonance Imaging

Article in several languages: English | deutsch
Hans-Martin Klein
MRI, Medical Center Siegerland Airport, Burbach, Germany
› Author Affiliations


Background For more than two decades, the focus of technological progress in MRI was restricted to systems with a field strength of 1.5 T and higher. Low- and mid-field MRI systems, which offer some specific advantages, are vanishing from the market. This article is intended to initiate a re-evaluation of the factor ‘field strength’ in MR imaging.

Method Literature review was carried out using MEDLINE database (via Pubmed) over a time span from 1980 to 2019 using free-text and Medical Subject headings (MeSH). Article selection was based on relevance and evidence.

Results and Conclusion Low-field MR systems are meanwhile rare in clinical imaging. MRI systems with a lower field strength provide a reduced signal-noise ratio (SNR) and spectral differentiation. However, these systems offer a variety of advantages: Shorter T1 relaxation, better T1 contrast, fewer metal artifacts, reduced susceptibility and chemical shift artifacts, fewer dielectric effects, better tissue penetration, less RF-power deposition, fewer ‘missile effects’, reduced effect on biomedical implants such as shunt valves, less energy and helium consumption. If we free ourselves from the constraints of high-field strength, we are able to offer multiple medical, economic and ecologic advantages to our patients. The development of high-quality low-field MRI is possible and necessary.

Key Points:

  • Static magnetic field strength is only one of many parameters influencing image quality in MR imaging.

  • Lower field strength results in a lower signal-to-noise ratio (SNR).

  • Modern MR systems offer technical tools to improve signal strength and reduce noise. This makes it possible to provide a diagnostic SNR at a lower field strength.

  • Low-field MR systems offer important advantages which have to be made available to our patients.

Citation Format

  • Klein H-M. Low-Field Magnetic Resonance Imaging. Fortschr Röntgenstr 2020; 192: 537 – 548

Publication History

Received: 21 November 2019

Accepted: 23 January 2020

Publication Date:
12 May 2020 (online)

© Georg Thieme Verlag KG
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