RT Journal Article
SR Electronic
T1 Considerations for Mean Upper Cervical Cord Area Implementation in a Longitudinal MRI Setting: Methods, Interrater Reliability, and MRI Quality Control
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
DO 10.3174/ajnr.A6394
A1 C. Chien
A1 V. Juenger
A1 M. Scheel
A1 A.U. Brandt
A1 F. Paul
YR 2020
UL http://www.ajnr.org/content/early/2020/01/23/ajnr.A6394.abstract
AB 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.CoVcoefficient of variationHPhealthy participantsICCintraclass correlation coefficientMUCCAmean upper cervical cord areaSCspinal cordSCTSpinal Cord ToolboxSRDsmallest real differenceUCCupper cervical cordDNDDay2day non-distortion correctedDDCDay2day distortion corrected cross-sectionalCNDCclinical non-distortion corrected cross-sectionalD’ADasymptotic test of equalityLoABland-Altman limits of agreementSEMstandard error of measurement