Fiber Tractography Lab

High-Definition Fiber Tractography (HDFT) is an advanced MRI-based non-invasive imaging technique used to study the intrinsic structure and connectivity of the living human brain, both in normal subjects and neurosurgery/neurology patients.

The Fiber Tractography Lab—under the direction of Fang-Cheng (Frank) Yeh, MD, PhD—is focused on the application of HDFT for presurgical planning and intraoperative navigation to facilitate brain function preservation and improve resection rates in patients with complex brain lesions. Dr. Yeh’s work is also centered on studying the structure and connectivity of the fiber tracts forming the “normal” human brain, and their structural alteration in patients with brain tumors, vascular lesions, stroke, and neurodegenerative diseases. 

These are the main areas of research:

Neuroanatomy of Fiber Tracts

Nearly two decades ago, Sir Francis Crick, neuroscientist, discoverer of the DNA molecule and 1962 Nobel Prize for Medicine, wrote: “to interpret the activity of living human brains, their neuroanatomy must be known in detail. New techniques to do this are urgently needed, since most of the methods now used on monkeys cannot be used on humans.” Nowadays, HDFT allows doctors and scientists to investigate the intrinsic structure of the brain with unprecedented detail, which will invariably facilitate a better understanding of brain functioning.

Studies in the Fiber Tractography Lab have contributed to elucidate the structure, connectivity, and potential functional role of the Middle Longitudinal Fascicle, Superior Longitudinal Fascicle and Arcuate Tract. We have also completed studies on the superior fronto-occipital fascicle, the claustro-cortical connections, and the dentate-rubro-thalamic tract.

Innovative studies using data from the Human Connectome Project are being completed to further elucidate the complex anatomy of the brainstem pathways, inferior longitudinal fascicle, and cingulum.

Presurgical Assessment of Fiber Tracts and Surgical Planning

HDFT provides a superior presurgical evaluation of the fiber tracts for patients with complex brain lesions, including low grade and high grade gliomas. Presurgical studies are built upon precise and accurate neuroanatomical knowledge, which allows doctors to reconstruct perilesional or intralesional fiber tracts, design the less invasive trajectory into the target lesion, and apply more effectively intraoperative electrical mapping techniques for maximal and safe tumor resection in eloquent cortical and subcortical regions. 

Our clinical experience applying HDFT has been reported in Neurosurgery, Journal of Neurosurgery, and Neuro-oncology among others; we are actively investigating its potential for not only presurgical planning and intraoperative navigation but also for neurostructural damage assessment, estimation of postsurgical neural pathways damage and recovery, and tracking of postsurgical changes and responses to rehabilitation therapy.

The latest innovation in the lab is HDFT reconstruction of cranial nerves for presurgical evaluation in skull base surgery, with very promising results. The ultimate goal is to facilitate brain function preservation and recovery in patients undergoing complex brain surgery.

Fiber Tract Integrity and Damage Progression in Neurodegenerative Disorders

Researchers are currently studying patients with ALS and Huntington Disease aiming to obtain quantifiable measures of white matter tract integrity that can be correlated with the speed of disease progression and with clinical measures. The ultimate goal is to find an accurate biomarker of the disease that can be monitored and serve as a reference for treatment response.

For more detailed information on the Fiber Tractography Lab, please visit