Tractography of the ansa lenticularis in the human brain

Abstract

The aim of this study was to make a thorough investigation of the trajectory of the ansa lenticularis (AL) and its subcomponents using high‐resolution fiber‐tracking tractography. The subcomponents of the AL were reconstructed from one region of interest (ROI) in the area of the globus pallidus combined with another ROI in the red nucleus, substantia nigra, subthalamic nucleus, or thalamus. This fiber‐tracking protocol was tested in an HCP‐1065 template, 35 healthy subjects from Massachusetts General Hospital (MGH), and 20 healthy subjects from the human connectome project (HCP) using generalized q‐sampling imaging (GQI)‐based tractography. Quantitative anisotropy and fractional anisotropy were also computed for the AL subcomponents. The subcomponents of the AL could be reconstructed in the HCP‐1065 template, 35 MGH healthy subjects, and 20 HCP healthy subjects. The AL descends from the globus pallidus and joins the ansa peduncularis for a short distance, subdividing later into fibers that continue separately to the red nucleus, substantia nigra, subthalamic nucleus, and thalamus. The study demonstrated the trajectory of the ansa lenticularis and its subcomponents using GQI‐based tractography, improving our understanding of the anatomical connectivity between the globus pallidus and the thalamo‐subthalamic region in the human brain. One Sentence Summary The investigation of the ansa lenticularis and its subcomponents using high‐resolution diffusion images based tractography.

In vivo probabilistic atlas of white matter tracts of the human subthalamic area combining track density imaging and optimized diffusion tractography

“…The few works attempting in vivo reconstruction of the pallidothalamic tracts, such as the AL or FL, are often based on small clinical samples (Rozanski et al 2017 ; Schlaier et al 2017 ) or group-averaged DWI datasets (Middlebrooks et al 2020 ; Li et al 2021 ). During its course from the anteromedial GPi, the AL first loops around the internal capsule describing a curve with anterior concavity and then it bends upwards forming a second curve at the level of the tegmentum to reach the ventral thalamus (Chung and Park 2020 ).…”

Correlation of diffusion tensor tractography with obstructive sleep apnea severity

“…Furthermore, QA quantifies anisotropy for each fiber population individually, providing a measurement for each fiber, unlike FA, which is shared by all fiber populations within a voxel. QA values are less affected by crossing fibers and partial volume effects, exhibiting better resolution and increased sensitivity to physiological variations (M. Li et al., 2022 , 2021 ). In clinical applications, diffusivity measurements like FA values demonstrate higher sensitivity to pathological conditions, whereas density measurements such as QA values exhibit heightened sensitivity to physiological variations (Yeh, Vettel et al., 2016 ).…”

Differential Tractography and Correlation Tractography Findings on Patients With Mild Traumatic Brain Injury: A Pilot Study

“…DTI will result in a large variation in the complexity of the biological changes due to its limitation in the restricted diffusion contributed by axonal myelination. The GQI can reconstruct fibers in complex neuroanatomical regions ( Panesar et al, 2019 ; Li et al, 2021a , b ) and tumors surrounding edema zones with accuracy ( Zhang et al, 2013 ; Celtikci et al, 2018 ). Furthermore, the QA, an anisotropy index calculated from the peak orientations on SDF through GQI, is less sensitive to the partial volume effects of crossing fibers.…”