Diffusion tensor imaging (DTI) and tractography in a normal subject depicting the decussation of the superior cerebellar peduncle (SCP). Axial FLAIR MR image with FA map overlay (A) shows the SCP decussation (arrow, red fibers) centrally in the ventral midbrain. Coronal FLAIR with FA map overlay (B) again depicts the SCP (arrow). By convention red denotes transversely orientated fibers, blue denotes craniocaudal orientated fibers and green denotes anteroposterior orientated fibers on DTI.
Tractographic reconstructions of the SCP (arrow) in the frontal plane (C) showing the central red dot of the SCP at the level of the midbrain. Abbreviations: CST (corticospinal tract), SLF (superior longitudinal fasciculus), MCP (middle cerebellar peduncle), PCF (pontocerebellar fiber).
Images obtained on a Siemens 3T Skyra scanner. Diffusion tensor imaging sequence parameter: diffusion-weighted single-shot spin-echo echoplanar sequence along 30 different geometric directions. An effective b-value of 1000 s/mm 2 was used for each of the 30 diffusion-encoding directions. Tractography was performed on Siemens Neuro 3D syngo software with ROI placed in the midbrain. Software setting: tract length 50-400 mm, 2 seed points per voxel length, angle threshold 30 degrees and FA threshold of 0.3.