Reliable volumetry of the cervical spinal cord in MS patient follow-up data with cord image analyzer (Cordial)

Abstract

Spinal cord (SC) atrophy is an important contributor to the development of disability in many neurological disorders including multiple sclerosis (MS). To assess the spinal cord atrophy in clinical trials and clinical practice, largely automated methods are needed due to the sheer amount of data. Moreover, using these methods in longitudinal trials requires them to deliver highly reliable measurements, enabling comparisons of multiple data sets of the same subject over time. We present a method for SC volumetry using 3D MRI data providing volume measurements for SC sections of fixed length and location. The segmentation combines a continuous max flow approach with SC surface reconstruction that locates the SC boundary based on image voxel intensities. Two cutting planes perpendicular to the SC centerline are determined based on predefined distances to an anatomical landmark, and the cervical SC volume (CSCV) is then calculated in-between these boundaries. The development of the method focused on its application in MRI follow-up studies; the method provides a high scan-rescan reliability, which was tested on healthy subject data. Scan-rescan reliability coefficients of variation (COV) were below 1 %, intra- and interrater COV were even lower (0.1-0.2 %). To show the applicability in longitudinal trials, 3-year follow-up data of 48 patients with a progressive course of MS were assessed. In this cohort, CSCV loss was the only significant predictor of disability progression (p = 0.02). We are, therefore, confident that our method provides a reliable tool for SC volumetry in longitudinal clinical trials.

Spinal cord volume loss

“…SCV analysis was performed using an established semiautomatic software (CORDIAL), which allows a fast and reliable segmentation and volumetry of the SC with minimal user interaction. 22,23 The segmentation was performed over a 35-mm-long SC segment, starting 27 mm below the cisterna pontis, which corresponds approximately to the SCV between the foramen magnum and the C2-3 intervertebral disk (figure e-1, links.lww.com/WNL/A588). Segmentations were visually inspected for quality and excluded from further statistical analysis in case of segmentation errors.…”

MAGNIMS consensus recommendations on the use of brain and spinal cord atrophy measures in clinical practice

“…Assessment of spinal cord atrophy is more difficult than brain segmentation owing to particular anatomical (higher mobility and smaller dimensions than the brain) and imaging (lower tissue contrast) features of the spinal cord. Semiautomated (Cordial) 147 and automated (Spinal Cord Toolbox) 148 tools have now been developed, based on deformable models. These promising new software tools still need to be extensively validated on independent datasets before they can even be considered for use in clinical practice.…”

Classification of multiple sclerosis based on patterns of CNS regional atrophy covariance

“…Spinal cord volume analysis was performed using the established CORDIAL semi-automatic software, as described in previous methodological and clinical studies (Amann et al, 2016;Tsagkas et al, 2018b). Shortly, the segmentation was carried out over a 35 mm long spinal cord segment, starting 27 mm below the cisterna pontis, which corresponds roughly to the spinal cord volume between the Foramen magnum and the C2/C3 intervertebral disk.…”