A score that predicts aquaporin-4 IgG positivity in patients with longitudinally extensive transverse myelitis

Eur J Neurol. 2023 Aug;30(8):2534-2538. doi: 10.1111/ene.15863. Epub 2023 May 26.


Background and purpose: Longitudinally extensive transverse myelitis (LETM) associated with aquaporin-4 autoantibodies (AQP4-IgG) can cause severe disability. Early diagnosis and prompt treatment are critical to prevent relapses. A novel score is described based on clinical and neuroimaging characteristics that predicts AQP4-IgG positivity in patients with LETM.

Methods: Patients were enrolled both retrospectively and prospectively from multiple Italian centers. Clinical and neuroimaging characteristics of AQP4-IgG positive and negative patients were compared through univariate and multivariate analysis.

Results: Sixty-six patients were included. Twenty-seven (41%) were AQP4-IgG positive and median age at onset was 45.5 years (range 19-81, interquartile range 24). Female sex (odds ratio [OR] 17.9, 95% confidence interval [CI] 2.6-381.9; p = 0.014), tonic spasms (OR 45.6, 95% CI 3.1-2197; p = 0.017) and lesion hypointensity on T1-weighted images (OR 52.9, 95% CI 6.8-1375; p = 0.002) were independently associated with AQP4-IgG positivity. The AQP4-IgG positivity in myelitis (AIM) score predicted AQP4-IgG positivity with 85% sensitivity and 95% specificity. Positive and negative likelihood ratios were 16.6 and 0.2 respectively. The inter-rater and intra-rater agreement in the score application were both excellent.

Conclusions: The AIM score predicts AQP4-IgG positivity with good sensitivity and specificity in patients with a first episode of LETM. The score may assist clinicians in early diagnosis and treatment of AQP4-IgG positive LETM.

Keywords: aquaporin 4; myelitis; neuromyelitis optica; transverse.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aquaporin 4
  • Autoantibodies
  • Female
  • Humans
  • Immunoglobulin G
  • Middle Aged
  • Myelitis, Transverse* / diagnostic imaging
  • Neoplasm Recurrence, Local
  • Neuromyelitis Optica* / diagnostic imaging
  • Retrospective Studies
  • Young Adult


  • Aquaporin 4
  • Immunoglobulin G
  • Autoantibodies