Timothy Michael Shepherd

Timothy Michael Shepherd, MD, PhD
Assistant Professor of Radiology
Key Personnel
2nd Floor 660 First Avenue New York, NY 10016
Educational Details: 

2006 MD/PhD (Neuroscience), University of Florida (Gainesville, FL)

2007 Internal Medicine Internship, University of Florida (Jacksonville, FL)

2011 Radiology Residency, University of California (San Francisco, CA)

2012 Neuroradiology Fellowship, University of California (San Francisco, CA)

Research Interest: 

I am seeking to understand the how the structural and functional organization of medial temporal lobe structures and cerebral cortex are affected by diseases such as epilepsy and Alzheimer’s disease. My approach is to use ex vivo MRI microscopy and ultra-high-field MRI of clinical patients to study human cerebral cortex and medial temporal lobe structures in normal and diseased states. The thesis of this research is that early changes to the functional organization of these structures can be detected by emerging MRI techniques during the preclinical stages of disease. This translational research focus could have an important impact on the contributions of neuroradiology to clinical management of patients, while also altering our fundamental understanding of local neuronal network organization in important brain substructures, such as the hippocampus. 

Selected Publications: 

1. TM Shepherd, SJ Blackband, ED Wirth. Simultaneous diffusion MRI measurements from multiple perfused rat hippocampal slices. Magn. Res. Med. 2002;48(3):565-569.

2. TM Shepherd, ED Wirth, PE Thelwall, HX Chen, SN Roper, SJ Blackband. Water diffusion measurements in perfused human hippocampal slices undergoing tonicity changes. Magn. Res. Med. 2003;49(5):856-863.

3. TM Shepherd, PE Thelwall, SJ Blackband, BR Pike, RL Hayes, ED Wirth. Diffusion magnetic resonance imaging studies of a rat hippocampal slice model of acute brain injury. J. Cereb. Bld. Flow. Metab. 2003;23(11):1461-1470.

4. E Özarslan, TM Shepherd, BC Vemuri, SJ Blackband, TH Mareci. Fast orientation mapping from HARDI. Medical Image Computing and Computer-Assisted Intervention – MICCAI 2005, Pt. 1 Lecture Notes in Computer Science. 2005;3749:156-163.

5. TM Shepherd, B Scheffler, MA King, GJ Stanisz, SJ Blackband. Magnetic resonance imaging of tissue slice cultures – A novel tissue model for studying chronic pathology and cell processes. Neuroimage 2006;30(3):780-6.

6. E Özarslan, TM Shepherd, BC Vemuri, SJ Blackband, TH Mareci. Resolution of complex tissue microarchitecture using the diffusion orientation transform (DOT). Neuroimage 2006;31(3):1086-1103.

7. PE Thelwall, TM Shepherd, GJ Stanisz, SJ Blackband. Effects of temperature and aldehyde fixation on tissue water diffusion properties, studied in an erythrocyte ghost tissue model. Magn. Res. Med. 2006;56(2):282-289.

8.  TM Shepherd, E Özarslan, MA King, TH Mareci, SJ Blackband. Structural insights from high-resolution diffusion tensor imaging and tractography of the isolated rat hippocampus. Neuroimage 2006;32(4):1499-509.

9. E Özarslan, PJ Basser, TM Shepherd, PE Thelwall, BC Vemuri, SJ Blackband. Observation of anomalous diffusion in excised tissue by characterizing the diffusion time dependence of the MR signal. J Magn Reson 2006;183(2):315-23.

10. E Özarslan, PJ Basser, TM Shepherd, PE Thelwall, BC Vemuri, SJ Blackband. Characterization of anomalous diffusion from MR signal may be a new probe to tissue microstructure. Conf Proc IEEE Eng Med Biol Soc. 2006;1:2256-9.

11. TM Shepherd, MA King, AT Yachnis, E Özarslan, SJ Blackband. Diffusion tensor microscopy indicates the cytoarchitectural basis for diffusion anisotropy in the human hippocampus. AJNR Am J Neuroradiol 2007;28:958-964.

12. A Barmpoutis, B Jian, BC Vemuri, TM Shepherd. Symmetric positive 4th order tensors & their estimation from diffusion-weighted MRI. Inf Process Med Imaging. 2007;20:308-19.

13. A Barmpoutis, BC Vemuri, TM Shepherd, JR Forder. Tensor splines for interpolation and approximation of DT-MRI with applications to segmentation of isolated rat hippocampi. IEEE Transactions on Medical Imaging  2007;26(11):1537-1546.

14. TM Shepherd, JJ Flint, PE Thelwall, GJ Stanisz, TH Mareci, AT Yachnis, SJ Blackband. Postmortem interval alters the water relaxation and diffusion properties of rat nervous tissue – Implications for MRI studies of human autopsy samples. Neuroimage 2009;44(3):820-826.

15.  TM Shepherd, PE Thelwall, GJ Stanisz, SJ Blackband. Aldehyde fixative solutions alter the water relaxation and diffusion properties of nervous tissue. Magn. Res. Med. 2009;62(1):26-34.

16. C von Morze, DA Kelley, TM Shepherd, S Banerjee, D Xu, CP Hess. Reduced field-of-view diffusion-weighted imaging of the brain at 7-T. Magn. Reson. Imaging. 2010;28(10):1541-5.

17. TM Shepherd, CP Hess, CT Chin, R Gould, WP Dillon. Reducing patient radiation dose during CT-guided procedures – demonstration in spinal injections for pain. AJNR Am J Neuroradiol 2011;32(10):1776-82.

18. TM Shepherd, IA Idokaji, M Hernandez-Pampaloni. Incidental detection of gastrointestinal stromal tumor by technetium 99m MDP bone scan. Clin Nuc Med 2011;37(2):198-9.

19. E Ozarslan, TM Shepherd, CG Koay, SJ Blackband, PJ Basser. Temporal scaling characteristics of diffusion as a new MRI contrast: Findings in rat hippocampus. Neuroimage 2012;60(2):1380-1393.

20. D Karampinos, G Melkus, TM Shepherd, S Banerjee, A Shankaranarayanan, CP Hess, T Link, WP Dillon, S Majumdar. Diffusion tensor imaging and T2 relaxometry of bilateral lumbar nerve roots: feasibility of in-plane imaging. NMR in Biomed 2013 (in press).

Research Projects: 

1.  PET-MRI and advanced structural MRI approaches to characterizing presymptomatic Alzheimer's disease.

2.  Quantitative structural 3-T MRI investigation of temporal lobe epilepsy and cortical dysplasia.

3.  Novel 3-T MRI sequence for specific diagnosis and prognosis in white matter hyperintensities.

4.  Coil and sequence development for acute spine imaging.

5.  MR microscopy of human brain specimens.


Philanthropic Support

We gratefully acknowledge generous support for radiology research at NYU Langone Health from:
• The Big George Foundation
• Raymond and Beverly Sackler
• Bernard and Irene Schwartz

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