Evaluation of reproducibility of diffusion tensor image analysis along the perivascular space index using a reorientation technique

Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index is expected to reflect the glymphatic function of the brain, however, head rotation may reduce reliability. This study evaluated whether a reorientation technique, which registers image and vector information of DTI data, improves the reproducibility of the calculation of the ALPS index. A total of 234 cognitively normal subjects were selected from the OASIS-3 dataset. In the evaluation of the intra- and inter-reliability, the reorientation technique enabled to show good to excellent reproducibility (intraclass correlation coefficients > 0.85) in calculating ALPS index even when head rotation existed.