Clarke, Geoffrey D PhDSchool of Medicine |
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Dr. Clarke received his PhD in Radiological Sciences from the University of Texas Health Science Center in Dallas in 1984. He has worked as a hospital physicist and pursued research interests in medical imaging physics, with emphasis on cardiovascular imaging and MRI. He is Director of the Graduate Program in Radiological Sciences. He is also Chief of the MRI Division and Assistant Director for Research at the UTHSCSA Research Imaging Institute. He serves as lead scientist for the NIH-funded Southwest Primate Research Center imaging core. His current research is concerned with developing imaging biomarkers for diabetes and cardiovascular research. |
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| 9/2006 - Present | Professor & Chief of Graduate Education | The University of Texas Health Science Center at San Antonio, Radiology, San Antonio, TX |
| Year | Degree | Discipline | Institution |
| 2013 | Postdoctoral Training | Translational Science | Institute for the Integration of Medicine and Science, UTHSCSA San Antonio , TX |
| 1984 | PhD | Radiological Sciences | The University of Texas Health Science Center at Dallas Dallas , TX |
| 1979 | MS | Radiological Physics | The University of Texas Health Science Center at Dallas Dallas , TX |
| 1979 | BA | Russian Language | The University of Texas at Arlington Arlington , TX |
| 1977 | BA | Physics & Psychology | North Texas State University Denton , TX |
Cardiovascular Imaging Physics- Magnetic Resonance Imaging of Coronary FLow and flow reserve, Regional Myocardial Blood Volume , Myocrdial Perfusion, and Vascular Imaging Agents. |
Imaging Physics and Equipment Quality Control- Procedures and programs for clinical MRI quality control and acceptance testing. Development of standard MRI phantom for quality control and accreditation. Supervised equipment quality control programs at Parkland Hospital and other clinical facilities. Taught graduate courses in the Physics of Diagnostic Radiology. |
In-vivo Magnetic Resonance Spectroscopy- P31 myocardial MRS in diabetes, x-linked hypophosphatemia and canine models of cardiac disease. H1 & P31 brain MRS in a blunt force head truama. |
Magnetic Resonance Imaging Physics- Managed MRI Laboratory at VCU/MCV 1984-1988; Proficent in design of RF coils and MRI pulse programming; taught graduate courses in MRI physics; dveeloped clinical MRI quality control tests & standards |
Metabolism, Diabetes and Reproductive Science- Research into the development of imaging biomarkers that correlate with traditional clinical metabolic parameters and molecular biological assay results. |
Radiation Safety in Diagnostic Radiology- Developed standards and methods for estiimating patient doses in diagnostic radiology - CT imaging and x-ray fluroroscopy. Methods for estimating dose for x-ray angiographic and cardiological imaging equipment. |
Radiation and Nuclear Physics- PET and SPECT measurements of metabolism and physiology in cardiac and diabetes research. Clinical nuclear medicine physics. |
| Date | Description | Institution | # Students |
| 8/2016 - Present | Pre-Doctoral Student Supervision | University of Texas Health Science Center | |
| 8/2016 - Present | Pre-Doctoral Student Supervision | University of Texas Health Science Center | |
| 7/2016 - Present | Pre-Doctoral Student Supervision | University of Texas Health Science Center | |
| 7/2013 - Present | Post-Doctoral Student Supervision | UTHSCSA | |
| 9/2012 - Present | Pre-Doctoral Student Supervision | UTHSCSA | |
Book/Monograph |
| Bushong SC, Clarke GD. Magnetic Resonance Imaging: Physical and Biological Principles, 4th edition St. Louis, MO: Elsevier Mosby; 2015. 513 p. |
Electronic/Web Publication |
| Valaparla SK,Gao F, Abdul-Ghani M, Clarke GD. Intramyocellular Lipid dependence on skeletal muscle fiber type and orientation characterized by diffusion tensor imaging and 1H-MRS 2014 Mar. Available from: http://dx.doi.org/10.1117/12.2041728 When muscle fibers are aligned with the B0 field, intramyocellular lipids (IMCL), important for providing energy during physical activity, can be resolved in proton magnetic resonance spectra (1H-MRS). Various muscles of the leg differ significantly in their proportion of fibers and angular distribution. This study determined the influence of muscle fiber type and orientation on IMCL using 1H-MRS and diffusion tensor imaging (DTI). Muscle fiber orientation relative to B0 was estimated by pennation angle (PA) measurements from DTI, providing orientation-specific extramyocellular lipid (EMCL) chemical shift data that were used for subject-specific IMCL quantification. Vastus lateralis (VL), tibialis anterior (TA) and soleus (SO) muscles of 6 healthy subjects (21-40 yrs) were studied on a Siemens 3T MRI system with a flex 4-channel coil. 1H-MRS were acquired using stimulated echo acquisition mode (STEAM, TR=3s, TE=270ms). DTI was performed using single shot EPI (b=600s/mm2, 30 directions, TR=4.5s, TE=82ms, and ten?5mm slices) with center slice indexed to the MRS voxel. The average PA?s measured from ROI analysis of primary eigenvectors were PA=19.46?5.43 for unipennate VL, 15.65?3.73 for multipennate SO, and 7.04?3.34 for bipennate TA. Chemical shift (CS) was calculated using [3cos2θ-1] dependence: 0.17?0.02 for VL, 0.18?0.01 for SO and 0.19?0.004 ppm for TA. IMCL-CH2 concentrations from spectral analysis were 12.77?6.3 for VL, 3.07?1.63 for SO and 0.27?0.08 mmol/kg ww for TA. Small PA?s were measured in TA and large CS with clear separation between EMCL and IMCL peaks were observed. Larger variations in PA were measured VL and SO resulting in an increased overlap of the EMCL on IMCL peaks. |
Journal Article |
| Kuo AD, Li C, Huber HF, Schwab M, Nathanielsz PW, Clarke GD. Maternal nutrient restriction during pregnancy and lactation leads to impaired right ventricular function in young adult baboons Journal of Physiology 2017 Apr;. |
| Franke K, Clarke GD, Dahnke R, Gaser C, Kuo AH, Li C, Schwab M, Nathanielsz PW. Premature Brain Aging in Baboons Resulting from Moderate Fetal Undernutrition Frontiers in Aging Neuroscience 2017 Apr;9(92). |
| Kuo AK, Li J, Li C, Huber HF, Schwab M, Nathanielsz PW, Clarke GD. Prenatal steroid administration leads to adult pericardial and hepatic steatosis in male baboons International Journal of Obesity (Lond) 2017 Apr;. |
| Kuo AK, Li C, Li J, Huber HF, Nathanielsz PW, Clarke GD. Cardiac Remodeling in a Baboon Model of Intrauterine Growth Restriction Mimics Accelerated Aging The Journal of Physiology 2017 Feb;595(4):1093-1110. |
| McGuire SA, Boone GR, Sherman PM, Tate DF, Wood JD, Patel B, Eskandar G, Wijtenburg SA, Rowland LM, Clarke GD, Grogan PM. White Matter Integrity in High-Altitude Pilots Exposed to Hypobaria Aerospace Medicine and Human Performance 2016 Dec;87(12):983-988. |
| Malloy KE, Li JQ, Choudhury GR, Torres A, Gupta S, Kantorak C, Goble T, Fox PT, Clarke GD, Daadi MM. Magnetic Resonance Imaging-Guided Delivery of Neural Stem Cells Into the Basal Ganglia of Nonhuman Primates Reveals a Pulsatile Mode of Cell Dispersion Stem Cells Transl Med 2016 Oct;(0269):877-885. |
| DeFronzo RA, Chilton R, Norton L, Clarke G, Ryder RE, Abdul-Ghani M. Revitalization of Pioglitazone: The Optimal Agent to be Combined with an SGLT2 Inhibitor Diabetes Obes Metab 2016 Feb;. |
| Papanikolaou N, Clarke GD, Watts LT, Maris, Thomas G, Pappas, Evangelos. MRI in Clinical Radiation Oncology: Dosimetry and Patient-Specific Plan Verification Magnetom World 2016 Jan;65(2):66-71. |
| Valaparla SK, Gao F, Daniele G, Abdul-Ghanni M, Clarke GD. Fiber orientation measurements by diffusion tensor imaging improve hydrogen-1 magnetic resonance spectroscopy of intramyocellular lipids in human leg muscles Journal of Medical Imaging 2015 Jun;2(2):1-9. |
| Prisciandaro JI, Willis CE, Burmeister JW, Clarke GD, Das RK, Esthappan J, Gerbi BJ, Harkness BA, Patton JA, Peck DJ, Pizzutiello RJ, Sandison GA, White SL, Wichman BD, Ibbott GS, Both S. Essentials and guidelines for clinical medical physics residency training programs: executive summary of AAPM Report Number 249 J Appl Clin Med Phys 2014 May;15(3):4763-4763. |
| Kasraie N, Mah P, Keener CR, Clarke GD. Characterization of atherosclerotic plaque: a contrast-detail study using multidetector and cone-beam computed tomography J Appl Clin Med Phys 2014 Jan;15(1). |
| Daniele G, Eldor R, Merovci A, Clarke GD, Xiong J, Tripathy D, Taranova A, Abdul-Ghani M, Defronzo RA. Chronic Reduction of Plasma FFA Improves Mitochondrial Function and Whole Body Insulin Sensitivity in Obese and Type 2 Diabetic Individuals Diabetes 2014 Jan;63(8):2812-2820. |
| Goerner F Duong T Stafford RJ Clarke GD . A comparison of five standard methods for evaluating image intensity uniformity in partially parallel imaging MRI Medical Physics 2013 Aug;40(8). |
| Goerner F, Clarke GD. Measuring Signal to Noise Ratio in Partially Parallel Imaging MRI Medical Physics 2011 Sep;38(9):5049-5057. |
| KasraieN, Oviatt HW, Clarke GD. On the Use of Molecular Weight Cutoff Cassettes to Measure Dynamic Relaxivity of Novel Gadolinium Contrast Agents: Example using Hyaluronic Acid Polymer Complexes in Phosphate Buffered Saline Radiology Research and Practice 2011 Jan;2011. |
Review Article |
| Clarke GD. Book Review: The Essential Physics of the Medical Imaging, 3rd edition Radiology 2015 Jan;274(1):64-65. |
| Drost DJ Riddle W CLARKE GD. Proton magnetic resonance spectroscopy in the brain: Report of AAPM MR task group #9 Medical Physics 2002 Sep;29(9):2177-2197. |
| Price RR, Allison J, Massoth RJ, CLARKE GD, Drost DJ. Practical aspects of functional MRI (NMR Task Group #8) Med Phys 2002 Aug;29(8):1892-1912. |
Federal |
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| Funding Agency | NIH |
| Title | The Southwest National Primate Research Center |
| Status | Active |
| Period | 6/2015 - 5/2016 |
| Role | Contributor |
| Grant Detail | Core Scientist (Scientific Unit for Regenerative Medicine and Aging), PI on Sub-Contract |
| Funding Agency | NIH / NIKKD |
| Title | Imaging Biomarkers for Evaluating Mitochondrial Function in Diabetes |
| Status | Active |
| Period | 9/2011 - 8/2015 |
| Role | Principal Investigator |
| Grant Detail | The overall goals of the proposed project are to develop these imaging methods to measure the concentrations of various chemicals in skeletal muscle that are important intermediaries of metabolism |