Automatic segmentation of the core of the acoustic radiation in humans

Abstract

IntroductionAcoustic radiation is one of the most important white matter fiber bundles of the human auditory system. However, segmenting the acoustic radiation is challenging due to its small size and proximity to several larger fiber bundles. TractSeg is a method that uses a neural network to segment some of the major fiber bundles in the brain. This study aims to train TractSeg to segment the core of acoustic radiation.MethodsWe propose a methodology to automatically extract the acoustic radiation from human connectome data, which is both of high quality and high resolution. The segmentation masks generated by TractSeg of nearby fiber bundles are used to steer the generation of valid streamlines through tractography. Only streamlines connecting the Heschl's gyrus and the medial geniculate nucleus were considered. These streamlines are then used to create masks of the core of the acoustic radiation that is used to train the neural network of TractSeg. The trained network is used to automatically segment the acoustic radiation from unseen images.ResultsThe trained neural network successfully extracted anatomically plausible masks of the core of the acoustic radiation in human connectome data. We also applied the method to a dataset of 17 patients with unilateral congenital ear canal atresia and 17 age- and gender-paired controls acquired in a clinical setting. The method was able to extract 53/68 acoustic radiation in the dataset acquired with clinical settings. In 14/68 cases, the method generated fragments of the acoustic radiation and completely failed in a single case. The performance of the method on patients and controls was similar.DiscussionIn most cases, it is possible to segment the core of the acoustic radiations even in images acquired with clinical settings in a few seconds using a pre-trained neural network.

Microstructural Changes in the Brainstem Auditory Pathway in Children With Hearing Loss

“…Prior studies of tractography on the auditory pathway have mainly focused on characterizing fibers of the auditory radiations (16,17). The novelty of our study stems from our application of tractography within the brainstem regions of the auditory pathway.…”

“…Furthermore, brain changes identified by DTI have been used to predict long-term auditory and speech outcomes after cochlear implantation (13,14), as well as school performance in children with hearing loss (15). Prior studies of the auditory pathway have mainly focused on characterizing more central ROIs and fibers that correspond to the auditory radiations (10,16,17). However, investigations of the brainstem in children with SNHL remains sparse, and no previous study has applied tractography to characterize this area in the context of congenital hearing loss.…”

Diffusion indices alteration in major white matter tracts of children with tic disorder using TRACULA

“…The increased RD in the left acoustic radiation found in our study is another novel finding. This tract originates in the medial geniculate nucleus (MGN) and curves anteriorly through the white matter within the transverse temporal gyrus to the primary auditory cortex [ 40 ]. The acoustic radiation, involved in auditory processing, has not been traditionally associated with motor function.…”

Automated three-dimensional major white matter bundle segmentation using diffusion magnetic resonance imaging

“…12 ), severe lesions in the pathways, or brain atrophy, similar to the manual approach and better compared with other methods (Wasserthal et al 2019 ). Furthermore, TractSeg was able to segment the core of the acoustic radiation, a relatively short fiber bundle (4–6 cm), in patients with congenital ear canal atresia (Siegbahn et al 2022 ).

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