Abstract
BACKGROUND AND PURPOSE: Spinal cord atrophy is commonly measured from cerebral MRIs, including the upper cervical cord. However, rescan intraparticipant measures have not been investigated in healthy cohorts. This study investigated technical and rescan variability in the mean upper cervical cord area calculated from T1-weighted cerebral MRIs.
MATERIALS AND METHODS: In this retrospective study, 8 healthy participants were scanned and rescanned with non-distortion- and distortion-corrected MPRAGE sequences (11–50 sessions in 6–8 months), and 50 participants were scanned once with distortion-corrected MPRAGE sequences in the Day2day daily variability study. From another real-world observational cohort, we collected non-distortion-corrected MPRAGE scans from 27 healthy participants (annually for 2–4 years) and cross-sectionally from 77 participants. Statistical analyses included coefficient of variation, smallest real difference, intraclass correlation coefficient, Bland-Altman limits of agreement, and paired t tests.
RESULTS: Distortion- versus non-distortion-corrected MPRAGE-derived mean upper cervical cord areas were similar; however, a paired t test showed incomparability (t = 11.0, P = <.001). Higher variability was found in the mean upper cervical cord areas calculated from an automatic segmentation method. Interrater analysis yielded incomparable measures in the same participant scans (t = 4.5, P = <.001). Non-distortion-corrected mean upper cervical cord area measures were shown to be robust in real-world data (t = −1.04, P = .31). The main sources of variability were found to be artifacts from movement, head/neck positioning, and/or metal implants.
CONCLUSIONS: Technical variability in cord measures decreased using non-distortion-corrected MRIs, a semiautomatic segmentation approach, and 1 rater. Rescan variability was within ±4.4% for group mean upper cervical cord area when MR imaging quality criteria were met.
ABBREVIATIONS:
- CoV
- coefficient of variation
- HP
- healthy participants
- ICC
- intraclass correlation coefficient
- MUCCA
- mean upper cervical cord area
- SC
- spinal cord
- SCT
- Spinal Cord Toolbox
- SRD
- smallest real difference
- UCC
- upper cervical cord
- DND
- Day2day non-distortion corrected
- DDC
- Day2day distortion corrected cross-sectional
- CNDC
- clinical non-distortion corrected cross-sectional
- D’AD
- asymptotic test of equality
- LoA
- Bland-Altman limits of agreement
- SEM
- standard error of measurement
Footnotes
Funding for this work was provided by the Deutsche Forschungsgemeinschaft DFG (EXC 257), awarded to F.P. and A.U.B.
Disclosures: Michael Scheel—UNRELATED: Patents (Planned, Pending or Issued): patent for 3D printing method; Royalties: from education books from Elsevier. Alexander Brandt—RELATED: Grant: BMBF, Comments: Neu2 ADVISIMS*; UNRELATED: Patents (planned, pending or issued): Retinal Image Analysis, Multiple sclerosis serum biomarkers, perceptive visual computing; Stock/stock options: Motognosis GmbH Nocturne GmbH. Friedemann Paul—OTHER RELATIONSHIPS: FP has received research support from Bayer, Novartis, Biogen Idec, Teva, Sanofi-Aventis/Genzyme, Merck Serono, Alexion, Chugai, Arthur Arnstein Foundation Berlin, Guthy Jackson Charitable Foundation and the US National Multiple Sclerosis Society; has received travel funding and/or speaker honoraria from Bayer, Novartis, Biogen Idec, Teva, Sanofi-Aventis/Genzyme and Merck Serono; and has consulted for Sanofi Genzyme, Biogen Idec and MedImmune; none of this is related to the present study. *Money paid to the institution.
- © 2020 by American Journal of Neuroradiology
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