Reproducibility of magnetic resonance imaging measurements of spinal cord atrophy: The role of quality assurance

A sensitive magnetic resonance imaging (MRI) method to measure spinal cord cross-sectional area with the potential to monitor disease progression has recently been developed, As changes in cord area due to disease are usually small, assessment of the reliability of the methodology is essential in se rial studies of spinal cord atrophy. The aim of this study was to institute and evaluate a protocol of quality assurance to determine long-term reprod ucibility of serial studies, Serial MRI of the spinal cord was carried out in five healthy volunteer controls over 1 year, Cross-sectional spinal cord areas were measured in a total of 46 scans, The mean coefficient of variat ion of all subjects over one year was 1.35%. The intra-observer coefficient of variation for same scan analysis was 0.63%. This study has confirmed hi gh reliability of our serial data over one year and the on-going quality as surance protocol enables continuing evaluation of the reproducibility of re sults in serial studies, Quality assurance is an essential and practical co mponent of all serial MRI studies, without which the clinical implications of change cannot be reliably evaluated. (C) 1999 Elsevier Science Inc.