Synthetic T2-weighted images of the lumbar spine derived from an accelerated T2 mapping sequence: Comparison to conventional T2w turbo spin echo

Marcus Raudner; Daniel F Toth; Markus M Schreiner; Tom Hilbert; Tobias Kober; Vladimir Juras; Reinhard Windhager; Siegfried Trattnig

doi:10.1016/j.mri.2021.09.011

Synthetic T₂-weighted images of the lumbar spine derived from an accelerated T₂ mapping sequence: Comparison to conventional T₂w turbo spin echo

Magn Reson Imaging. 2021 Dec:84:92-100. doi: 10.1016/j.mri.2021.09.011. Epub 2021 Sep 23.

Authors

Marcus Raudner¹, Daniel F Toth², Markus M Schreiner³, Tom Hilbert⁴, Tobias Kober⁴, Vladimir Juras⁵, Reinhard Windhager³, Siegfried Trattnig⁶

Affiliations

¹ Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging (MOLIMA), High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria. Electronic address: marcus.raudner@meduniwien.ac.at.
² Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria.
³ Department of Orthopaedics and Trauma Surgery, Medical University of Vienna, Austria.
⁴ Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland; Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland; LTS5, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
⁵ Christian Doppler Laboratory for Clinical Molecular MR Imaging (MOLIMA), High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria; Department of Imaging Methods, Institute of Measurement Science, Bratislava, Slovakia.
⁶ Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging (MOLIMA), High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria.

PMID: 34562566
DOI: 10.1016/j.mri.2021.09.011

Abstract

Objectives: To evaluate the diagnostic usefulness of synthetic T₂-weighted images of the lumbar spine derived from ten-fold undersampled k-space data using GRAPPATINI, a combination of a model-based approach for rapid T₂ and M₀ quantification (MARTINI) extended by generalized autocalibrating partial parallel acquistion (GRAPPA).

Materials and methods: Overall, 58 individuals (26 female, mean age 23.3 ± 8.1 years) were examined at 3 Tesla with sagittal and axial T₂w turbo spin echo (TSE) sequences compared to synthetic T₂_-weighted contrasts derived at identical effective echo times and spatial resolutions. Two blinded readers graded disk degeneration and evaluated the lumbar intervertebral disks for present herniation or annular tear. One reader reassessed all studies after four weeks. Weighted kappa statistics were calculated to assess inter-rater and intra-rater agreement. Also, all studies were segmented manually by one reader to compute contrast ratios (CR) and contrast-to-noise ratios (CNR) of the nucleus pulposus and the annulus fibrosus.

Results: Overall, the CR_T2w was 4.45 ± 1.80 and CR_T2synth was 4.71 ± 2.14. Both correlated (rsp = 0.768;p < 0.001) and differed (0.26 ± 1.38;p = 0.002) significantly. The CNR_T2w was 1.73 ± 0.52 and CNR_T2synth was 1.63 ± 0.50. Both correlated (rsp = 0.875;p < 0.001) and differed (-0.10 ± 0.25;p < 0.001) significantly. The inter-rater agreement was substantial to almost perfect (κ = 0.808-0.925) with the intra-rater agreement also substantial to almost perfect (κ = 0.862-0.963). The area under the curve of the receiver operating characteristics assessing disk herniation or annular tear ranged from 0.787 to 0.892.

Conclusions: This study concludes that synthetic images derived by GRAPPATINI can be used for clinical routine assessment with inter-rater and intra-rater agreements comparable to conventional T₂w TSE.

Keywords: Intervertebral disc; Intervertebral disc degeneration; Intervertebral disc discplacement; Spine.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Female
Humans
Intervertebral Disc Degeneration* / diagnostic imaging
Intervertebral Disc Displacement* / diagnostic imaging
Intervertebral Disc* / diagnostic imaging
Lumbar Vertebrae / diagnostic imaging
Magnetic Resonance Imaging / methods
Young Adult