A novel MRI index for paraspinal muscle fatty infiltration: reliability and relation to pain and disability in lumbar spinal stenosis: results from a multicentre study

Hasan Banitalebi; Jørn Aaen; Kjersti Storheim; Anne Negård; Tor Åge Myklebust; Margreth Grotle; Christian Hellum; Ansgar Espeland; Masoud Anvar; Kari Indrekvam; Clemens Weber; Jens Ivar Brox; Helena Brisby; Erland Hermansen

doi:10.1186/s41747-022-00284-y

A novel MRI index for paraspinal muscle fatty infiltration: reliability and relation to pain and disability in lumbar spinal stenosis: results from a multicentre study

Eur Radiol Exp. 2022 Jul 20;6(1):38. doi: 10.1186/s41747-022-00284-y.

Authors

Hasan Banitalebi^{1

2}, Jørn Aaen^{3

4}, Kjersti Storheim⁵, Anne Negård^{6

7}, Tor Åge Myklebust^{8

9}, Margreth Grotle^{5

10}, Christian Hellum¹¹, Ansgar Espeland^{12

13}, Masoud Anvar¹⁴, Kari Indrekvam^{13

15}, Clemens Weber^{16

17}, Jens Ivar Brox¹⁸, Helena Brisby^{19

20}, Erland Hermansen^{3

21}

Affiliations

¹ Department of Diagnostic Imaging, Akershus University Hospital, Lørenskog, Norway. [email protected].
² Institute of Clinical Medicine, University of Oslo, Oslo, Norway. [email protected].
³ Department of Orthopaedic Surgery, Ålesund Hospital, Møre and Romsdal Hospital Trust, Ålesund, Norway.
⁴ Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
⁵ Communication and Research Unit for Musculoskeletal Health (FORMI), Oslo University Hospital, Oslo, Norway.
⁶ Department of Diagnostic Imaging, Akershus University Hospital, Lørenskog, Norway.
⁷ Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
⁸ Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund, Norway.
⁹ Department of Registration, Cancer Registry Norway, Oslo, Norway.
¹⁰ Department of Physiotherapy, Faculty of Health Science, Oslo Metropolitan University, P.O. box 4, St. Olafs plass, Oslo, Norway.
¹¹ Division of Orthopaedic Surgery, Oslo University Hospital Ulleval, Oslo, Norway.
¹² Department of Radiology, Haukeland University Hospital, Bergen, Norway.
¹³ Department of Clinical Medicine, University of Bergen, Bergen, Norway.
¹⁴ Unilabs Radiology, Oslo, Norway.
¹⁵ Kysthospitalet in Hagevik. Orthopaedic Clinic, Haukeland University Hospital, Bergen, Norway.
¹⁶ Department of Neurosurgery, Stavanger University Hospital, Stavanger, Norway.
¹⁷ Department of Quality and Health Technology, University of Stavanger, Stavanger, Norway.
¹⁸ Department of Physical Medicine and Rehabilitation, Oslo University Hospital, Oslo, Norway.
¹⁹ Department of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden.
²⁰ Department of Orthopaedics, Institute for clinical sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
²¹ Hofseth BioCare, Ålesund, Norway.

Abstract

Background: Fatty infiltration of the paraspinal muscles may play a role in pain and disability in lumbar spinal stenosis. We assessed the reliability and association with clinical symptoms of a method for assessing fatty infiltration, a simplified muscle fat index (MFI).

Methods: Preoperative axial T2-weighted magnetic resonance imaging (MRI) scans of 243 patients aged 66.6 ± 8.5 years (mean ± standard deviation), 119 females (49%), with symptomatic lumbar spinal stenosis were assessed. Fatty infiltration was assessed using both the MFI and the Goutallier classification system (GCS). The MFI was calculated as the signal intensity of the psoas muscle divided by that of the multifidus and erector spinae. Observer reliability was assessed in 102 consecutive patients for three independent investigators by intraclass correlation coefficient (ICC) and 95% limits of agreement (LoA) for continuous variables and Gwet's agreement coefficient (AC1) for categorical variables. Associations with patient-reported pain and disability were assessed using univariate and multivariate regression analyses.

Results: Interobserver reliability was good for the MFI (ICC 0.79) and fair for the GCS (AC1 0.33). Intraobserver reliability was good or excellent for the MFI (ICC range 0.86-0.91) and moderate to almost perfect for the GCS (AC1 range 0.55-0.92). Mean interobserver differences of MFI measurements ranged from -0.09 to -0.04 (LoA -0.32 to 0.18). Adjusted for potential confounders, none of the disability or pain parameters was significantly associated with MFI or GCS.

Conclusion: The proposed MFI demonstrated high observer reliability but was not associated with preoperative pain or disability.

Keywords: Magnetic resonance imaging; Paraspinal muscles; Patient-reported outcome measures; Psoas muscles; Spinal stenosis.

Publication types

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

MeSH terms

Female
Humans
Magnetic Resonance Imaging / methods
Pain / pathology
Paraspinal Muscles* / diagnostic imaging
Paraspinal Muscles* / pathology
Reproducibility of Results
Spinal Stenosis* / diagnostic imaging
Spinal Stenosis* / pathology