Tractography-based connectomes are dominated by false-positive connections

Abstract

Fiber tractography based on non-invasive diffusion imaging is at the heart of connectivity studies of the human brain. To date, the approach has not been systematically validated in ground truth studies. Based on a simulated human brain dataset with ground truth white matter tracts, we organized an open international tractography challenge, which resulted in 96 distinct submissions from 20 research groups. While most state-of-the-art algorithms reconstructed 90% of ground truth bundles to at least some extent, on average they produced four times more invalid than valid bundles. About half of the invalid bundles occurred systematically in the majority of submissions. Our results demonstrate fundamental ambiguities inherent to tract reconstruction methods based on diffusion orientation information, with critical consequences for the approach of diffusion tractography in particular and human connectivity studies in general.

Adolescent Tuning of Association Cortex in Human Structural Brain Networks

“…Still, an advantage of structural correlation networks over structural connectomes derived from diffusion imaging using tractography is the relative simplicity of the structural MRI acquisitions compared with diffusion imaging, which in light of its longer acquisition is more prone to motion artefacts (Yendiki et al 2014), and within which tractography presents considerable challenges (Thomas et al 2014; Reveley et al 2015; Maier-Hein et al 2016). Efforts to derive measures of individual contribution to structural correlation networks (Saggar et al 2015) or fully individual networks from structural imaging (Tijms et al 2012; Kong et al 2014, 2015) including through the combination of multimodal features (Seidlitz et al 2017) should increase the practical applicability of structural correlation network research.…”

Toward an electrophysiological “sweet spot” for deep brain stimulation in the subthalamic nucleus

“…Data was processed using a generalized q‐sampling imaging algorithm [Yeh et al, ] as implemented in DSI studio (http://dsi-studio.labsolver.org; RRID:SCR_009557). With the 92% valid connections, the deterministic fiber tracking approach implemented in DSI studio achieved the highest valid connection count in comparison to 96 methods submitted from 20 different research groups in a recent open competition [Maier‐Hein et al, ]. A white matter mask was estimated by segmenting the T2‐weighted anatomical images and co‐registering the images to the b0 image of the diffusion data using SPM12.…”

Short-range connections in the developmental connectome during typical and atypical brain maturation

“…Current available dMRI-based tractography algorithms are known to suffer from false positives, especially in periventricular regions (e.g. Maier-Hein et al, 2016). All these challenges are further amplified in studies that involve developmental brains as there is no reliable way to check the accuracy of the trajectories due to lack of comprehensive and longitudinal dMRI atlas for developing brain.…”