LAUSR

ObjectiveTo validate the precision and accuracy of the semi-automated cord image analyser (Cordial) for lumbar spinal cord (SC) volumetry in 3D T1w MRI data of healthy controls (HC).Materials and methods40 3D T1w images of 10 HC (w/m: 6/4; age range: 18–41 years) were acquired at one 3T-scanner in two MRI sessions (time interval 14.9±6.1 days). Each subject was scanned twice per session, allowing determination of test-retest reliability both in back-to-back (intra-session) and scan-rescan images (inter-session). Cordial was applied for lumbar cord segmentation twice per image by two raters, allowing for assessment of intra- and inter-rater reliability, and compared to a manual gold standard.ResultsWhile manually segmented volumes were larger (mean: 2028±245 mm3 vs. Cordial: 1636±300 mm3, p<0.001), accuracy assessments between manually and semi-automatically segmented images showed a mean Dice-coefficient of 0.88±0.05. Calculation of within-subject coefficients of variation (COV) demonstrated high intra-session (1.22–1.86%), inter-session (1.26–1.84%), as well as intra-rater (1.73–1.83%) reproducibility. No significant difference was shown between intra- and inter-session reproducibility or between intra-rater reliabilities. Although inter-rater reproducibility (COV: 2.87%) was slightly lower compared to all other reproducibility measures, between rater consistency was very strong (intraclass correlation coefficient: 0.974).ConclusionWhile under-estimating the lumbar SCV, Cordial still provides excellent inter- and intra-session reproducibility showing high potential for application in longitudinal trials.Key Points• Lumbar spinal cord segmentation using the semi-automated cord image analyser (Cordial) is feasible.• Lumbar spinal cord is 40-mm cord segment 60 mm above conus medullaris.• Cordial provides excellent inter- and intra-session reproducibility in lumbar spinal cord region.• Cordial shows high potential for application in longitudinal trials.