Mitigating gyral bias in cortical tractography via asymmetric fiber orientation distributions

Ye Wu, Yoonmi Hong, Yuanjing Feng, Dinggang Shen, Pew Thian Yap

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Diffusion tractography in brain connectomics often involves tracing axonal trajectories across gray-white matter boundaries in gyral blades of complex cortical convolutions. To date, gyral bias is observed in most tractography algorithms with streamlines predominantly terminating at gyral crowns instead of sulcal banks. This work demonstrates that asymmetric fiber orientation distribution functions (AFODFs), computed via a multi-tissue global estimation framework, can mitigate the effects of gyral bias, enabling fiber streamlines at gyral blades to make sharper turns into the cortical gray matter. We use ex-vivo data of an adult rhesus macaque and in-vivo data from the Human Connectome Project (HCP) to show that the fiber streamlines given by AFODFs bend more naturally into the cortex than the conventional symmetric FODFs in typical gyral blades. We demonstrate that AFODF tractography improves cortico-cortical connectivity and provides highly consistent outcomes between two different field strengths (3T and 7T).

Original languageEnglish
Article number101543
JournalMedical Image Analysis
Publication statusPublished - 2020 Jan


  • Asymmetric fiber orientation distribution
  • Diffusion MRI
  • Gyral bias
  • Tractography

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Computer Vision and Pattern Recognition
  • Health Informatics
  • Computer Graphics and Computer-Aided Design


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