Reliable and fast volumetry of the lumbar spinal cord using cord image analyser (Cordial)
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To 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 methods
40 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.
While 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).
While under-estimating the lumbar SCV, Cordial still provides excellent inter- and intra-session reproducibility showing high potential for application in longitudinal trials.
• 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.
KeywordsSpinal cord Volumetry Semi-automated segmentation Magnetic resonance imaging Imaging biomarker
Central nervous system
Coefficient of variation
Intra-class correlation coefficient
Magnetisation-prepared rapid gradient-echo
Spinal cord volume
Volumetric interpolated breath-hold examination
We would like to thank Tanja Haas and Pascal Kuster for MRI data acquisition and data management. Most of all, we are grateful to the healthy controls for participating in the study. Data acquisition was funded by F. Hoffman La Roche. F. Hoffman La Roche did not have any additional role in the study design, data collection, analysis, interpretation of data, writing of the report and decision to submit the paper for publication.
Data acquisition was funded by F. Hoffman La Roche. F. Hoffman La Roche did not have any additional role in the study design, data collection, analysis, interpretation of data, writing of the report and decision to submit the paper for publication.
KP holds a personal grant of the Baasch Medicus Foundation Switzerland.
Compliance with ethical standards
The scientific guarantor of this publication is PD Dr. Katrin Parmar.
Conflict of interest
C.T., A.A., U.B., S.P., J.R., M.A., P.C. and D.F. declare no relationships with any companies whose products or services may be related to the subject matter of the article.
J.W. is CEO of MIAC AG Basel. Unrelated to this work he received grants from the German Ministry of Science (BMBF), the German Ministery of Economy (BMWI), the EU (Horizon2020) and compensation for talks and advisory boards from Actelion, Bayer, Biogen, Genzyme, Novartis, Roche.
K.P. received travel support from Novartis Switzerland unrelated to this work.
A.F. reports travel support from Bracco Switzerland unrelated to this work.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Written informed consent was obtained from all subjects in this study.
Institutional Review Board approval was obtained.
• method validation
• performed at one institution
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