140 likes | 145 Views
This research study aims to provide normative data for articulatory therapy, speech synthesis, and speech science by imaging speech anatomy and behavior. It also explores clinical applications such as surgical planning and diagnosis of biomechanical defects. The study addresses difficult imaging problems through segmentation techniques and high-speed dynamic imaging.
E N D
Preliminary Work and Proposed Continuation: Imaging of Speech Anatomy and Behavior Mark Hasegawa-Johnson, ECE Department Thomas Conturo, Washington University Xuming He, Illinois David Kuehn, Illinois Zhi-Pei Liang, Illinois Jeff Marsh, Children's Hospital St. Louis Lynn Marty-Grames, Children's Hospital Jerry Moon, Iowa Victor Schepkin, Illinois Reiner Wilhelms-Tricarico, MIT
Outline • History: Normative Data • Future: Clinical Data • Difficult Imaging Problems and Possible Solutions
Normative Data: Speech PostureHasegawa-Johnson et al., http://www.ifp.uiuc.edu/speech/mri • Purpose: Normative data for articulatory therapy, speech synthesis, speech science. • 3mm Multislice, 750ms/image, 25 seconds breath hold.
Normative Tagged Cine-MRIStone et al., 2001 • Purpose: Direct observation of biomechanical quantities. • Limitation: 32 repetitions per image sequence.
Diffusion Tensor MRI, Bovine TongueWedeen et al., 2001 • Purpose: Muscle segmentation, structure. • Limitation: Long acquisition => animal specimens.
Clinical Objective: Surgical PlanningKacker, 2000 Beckwith-Wiedemann Syndrome • Normal intelligence, personality. • At least 9 published resection methods; no quantitative comparison of results.
Finite Element Modeling of Surgery Objective of Proposed Preliminary Study: Simulate effects of two common surgeries. Limitation: detailed knowledge of structure & biomechanical properties.
Clinical Data: Surgical, Cadaver Samples Microscopic imaging of surgically excised tissue, Diffusion tensor imaging of muscle structure (goal: first DTI of human tongue). Target Resolution: fascicle thickness = 0.1mm.
Clinical Data: Pre-operative and Post-operative MRI Objective: Surgical Planning Objective: Post-surgical follow-up, correlation of anatomical and behavioral variables Limitation: Muscle-Muscle Segmentation
Clinical: Kinematic Diagnosis Objective: Identify correlations between anatomy, behavior. Limitation: Speed.
Difficult Imaging Problems • Segmentation: Transverse and longitudinal muscle indistinguishable w/o diffusion weighting. • Diffusion Weighting: Ambiguous in presence of blood flow. • Speed: • Sedated: 20 minutes. • Breath hold: 5 seconds. • Dynamic: 10-50 ms.
Possible Solution: Segmentation • Bayesian image segmentation -- combine: • Prior knowledge (other segmented volumes) • Ambiguous anatomical image • Ambiguous diffusion tensor image • User-supplied "hints"
Possible Solutions: Speed • Image-recognition based image reconstruction • RIGR (Liang 1992): Morph a prior image to match partial k-space data. • Prior information about tongue shape, e.g. from factor analysis of normative tongue shapes (Hasegawa-Johnson & Zheng, 1999):
Conclusions • Speech Science Research Issues • Muscle fiber organization • Strain dynamics of soft tissue • Clinical Applications • Surgical planning • Diagnosis of biomechanical defects • Difficult Imaging Problems • Segmentation of inter-muscle boundaries • High-speed dynamic imaging