Evaluation of Reliability of Dynamic Scapholunate Distance Measured on 4D CT-Acquired Images

Purpose  A technique to measure scapholunate distance based on four-dimensional computed tomography (4D CT)-acquired images is presented. Materials and Methods  Intra-observer variability was evaluated through a repeated-measures study. A 4D CT of seven patients suspected of scapholunate lesion was performed. Anatomical landmarks were identified on a three-dimensional reconstructed model of the wrist. All 4D CT datasets were evaluated thrice by two observers. Standard deviation of the differences between two measurements, interclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated. Results  Intra-observer variability for the expert observer (ICC > 0.95) was lower than that of the novice observer (ICC > 0.77) and interobserver variability was low (ICC > 0.85). For the expert observer, measurement error (SEM < 0.13 mm and MDC < 0.36 mm) was smaller than that of the novice observer (SEM < 0.45 mm and MDC < 1.24 mm). Both SEM and MDC values were low, compared to the scan resolution and the absolute value of intervals. Conclusion  The proposed assessment results in a reproducible and reliable measurement of scapholunate distance.