Fig. 1

Magnetic resonance imaging-based assessment of the surface and area of the superior oblique muscle (SOM). Imaging sequence: High-resolution-3D-T2-gradient-echo CISS sequence centered on the SOM. Left column: native view, not used for study measurements. Right column: multiplanar reconstructions - perpendicular (axial view) and longitudinal (sagittal view) along the muscle axis (arrows) using an oblique three-dimensional tool, representing the measurement methodology applied in the study. The coronal muscle section slice is the plane of interest for SOM analysis. SOM analysis row: demonstrates measurement differences between native and reconstructed SOM analysis. Surface measurement: performed using the “irregular region of interest” tool. Area calculation: defined as width (larger axis of the muscle section) multiplied by length (shortest axis).