Cranial nerve tractography with 3T PROPELLER Diffusion Tensor Imaging

[Introduction] Cranial nerves are small nerves that control various sensory and/or motor functions and these nerves emerge from the brainstem. Conventional anatomical scan such as T1/T2 weighed MRI is commonly used to identify these nerves, but sometimes it is difficult to track the pathways due to complex structure. To visualize complex fiber structure, Diffusion Tensor Imaging (DTI) has been successfully demonstrated in elsewhere. 3Tesla MRI has high signal to noise ratio (SNR) comparing to lower field (1.5T) MRI, so it is expected that small neuro anatomy such as cranial nerves can be visualized by using high SNR of 3T. Single shot Echo Planar Imaging (ssEPI) based DTI acquisition is commonly used to suppress image ghost caused by phase shift induced from patient motion. Although ssEPI made great success in DTI and DTT application, it is sensitive to magnetic susceptibility and image distortion artifact or signal loss may result, especially at high field strength such as 3T. PROPELLER-DWI [1] is a FSE based diffusion acquisition sequence and PROPELLER based diffusion tensor image acquisition technique was used to avoid severe susceptibility effect on high field MRI. In this paper, 3T PROPELLER-DTT was studied to show its usefulness for cranial nerves tractography.