HAFT

Fiber Tractography Lab

The Fiber Tractography Lab—under the direction of Fang-Cheng (Frank) Yeh, MD, PhD—is focused on the application of novel imaging methods 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 diseasess. 

These are the main areas of research:

High Accuracy Fiber Tracking

High Accuracy Fiber Tracking (HAFT) is a technology that applies the combination of a novel acquisition method of brain MRI images with generalized q-sampling imaging to map brain connections. This unique combination allows HAFT to achieve an error rate down to 7~8%, a substantial improvement over the 50~40% error of existing technologies. This high accuracy was examined in an open competition, which was later published in Nature Communication. HAFT has been used to study the intrinsic structure and connectivity of the living human brain, both in normal subjects and neurosurgery/neurology patients.

Neuroanatomy of Fiber Tracts

Innovative studies using data from the Human Connectome Project have been conducted to elucidate the complex anatomy of the brain pathways. In the Fiber Tractography Lab, HAFT 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 major fiber pathways

Presurgical Assessment of Fiber Tracts and Surgical Planning

HAFT 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 HAFT 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 HAFT 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 sites.google.com/view/hdft-at-pitts.