Image Quality of Lumbar Spine Imaging at 0.55T Low-Field MRI is Comparable to Conventional 1.5T MRI - Initial Observations in Healthy Volunteers

Hanns-Christian Breit; Jan Vosshenrich; Verena Hofmann; Thilo Rusche; Balázs K Kovacs; Michael Bach; Sebastian Manneck; Dorothee Harder

doi:10.1016/j.acra.2023.01.037

Image Quality of Lumbar Spine Imaging at 0.55T Low-Field MRI is Comparable to Conventional 1.5T MRI - Initial Observations in Healthy Volunteers

Acad Radiol. 2023 Nov;30(11):2440-2446. doi: 10.1016/j.acra.2023.01.037. Epub 2023 Feb 24.

Authors

Hanns-Christian Breit¹, Jan Vosshenrich², Verena Hofmann¹, Thilo Rusche¹, Balázs K Kovacs¹, Michael Bach¹, Sebastian Manneck³, Dorothee Harder¹

Affiliations

¹ Department of Radiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
² Department of Radiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland. Electronic address: jan.vosshenrich@usb.ch.
³ Department of Radiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland; Department of Radiology, Gesundheitszentrum Fricktal AG, Rheinfelden, Switzerland.

PMID: 36841743
DOI: 10.1016/j.acra.2023.01.037

Abstract

Rationale and objectives: To assess the potential of 0.55T low-field MRI system in lumbar spine imaging with and without the use of additional advanced postprocessing techniques.

Materials and methods: The lumbar spine of 14 volunteers (32.9 ± 3.6 years) was imaged both at 0.55T and 1.5T using sequences from clinical routine. On the 0.55T scanner system, additional sequences with simultaneous multi-slice acquisition and artificial intelligence-based postprocessing techniques were acquired. Image quality of all 28 examinations was assessed by three musculoskeletal radiologists with respect to signal/contrast, resolution, and assessability of the spinal canal and neuroforamina using a 5-point Likert scale (1 = non-diagnostic to 5 = perfect quality). Interrater agreement was evaluated with the Intraclass Correlation Coefficient and the Mann-Whitney U test (significance level: p < 0.05).

Results: Image quality at 0.55T was rated lower on the 5-point Likert scale compared to 1.5T regarding signal/contrast (mean: 4.16 ± 0.29 vs. 4.54 ± 0.29; p < 0.001), resolution (4.07 ± 0.31 vs. 4.49 ± 0.30; p < 0.001), assessability of the spinal canal (4.28 ± 0.13 vs. 4.73 ± 0.26; p < 0.001) and the neuroforamina (4.14 ± 0.28 vs. 4.70 ± 0.27; p < 0.001). Image quality for the AI-processed sagittal T1 TSE and T2 TSE at 0.55T was also rated slightly lower, but still good to perfect with a concomitant reduction in measurement time. Interrater agreement was good to excellent (range: 0.60-0.91).

Conclusion: While lumbar spine image quality at 0.55T is perceived inferior to imaging at 1.5T by musculoskeletal radiologists, good overall examination quality was observed with high interrater agreement. Advanced postprocessing techniques may accelerate intrinsically longer acquisition times at 0.55T.

Keywords: 0.55T; Low-Field MRI; lumbar spine; magnetic resonance imaging.