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Center for NMR Research

Christopher M. Collins, Ph.D.

Assistant Professor
Center for NMR Research
Department of Radiology/ NMR Building, H066
Penn State College of Medicine
500 University Drive
Hershey, PA 17033
Phone: 717-531-7402
Fax: 717-531-8486
Email: cmcollins@psu.edu

Education

Ph.D. (Bioengineering) University of Pennsylvania, 1999
M.S. (Bioengineering) University of Pennsylvania, 1995
B.S. (Engineering Science) Pennsylvania State University, 1993

Research Interests

Engineering of electromagnetic (EM) fields in the human body for MRI is an important, interesting, and complex problem. The tissues in the body have their own electromagnetic properties and thus interact with the fields we apply in MRI in several ways. Some of these interactions result in the signal we use to create images, some give us image contrast yielding important anatomical and physiological information, and some act to distort the fields and adversely affect image integrity. Also, while we strive to use MRI to improve human health, there are certain hazards associated with exposure to EM fields.

There are potentially many creative wasy to improve MRI and MRI safety by manipulating the EM fields in the human body, but doing so first requires means of accurately predicting these fields. Calculation of EM field behavior in the body requires accurate models of both the human body and MRI magnets (with frequencies currently ranging from 0 to 400MHz for imaging of humans), as well as complete consideration of Maxwell’s equations for electromagnetics in three dimensions. We have developed methods for predicting the effects of field distortions caused by the human body as seen in MRI, validated these methods with comparison to analytical calculations and experimental measurements, and made some interesting observations and predictions regarding these interactions. We are currently seeking new ways to improve MRI in the presence of such distortions.

Selected Publications

Collins CM, Liu W, Swift BJ, Smith MB. Combination of optimized transmit arrays and some parallel imaging reconstruction methods can yield homogeneous images at very high frequencies. Magn. Reson. Med. 54:1327-1332, 2005.
Van de Moortele P-F, Akgun C, Adriany G, Moeller S, Ritter J, Collins CM, Smith MB, Vaughan JT, Ugurbil K. B1 interferences and spatial phase patterns at 7 tesla with a head transceiver array coil. Magn. Reson. Med. 54:1503-1518, 2005.
Maril N, Collins CM, Greenman RL, Lenkinski RE. Strategies for shimming the breast. Magn. Reson. Med. 54:1139-1145, 2005.
Sun L, Collins CM, Schiano JL, Smith MB, Smith NB. Adaptive real-time closed-loop temperature control for ultrasound hyperthermia using magnetic resonance thermometry. Concepts Magn. Reson. 27B:51-63, 2005.
Liu W, Collins CM, Smith MB. Calculations of B1 distribution, Specific Energy Absorption Rate, and Intrinsic Signal-to-Noise Ratio for a Body-size Birdcage Coil Loaded with Different Human Subjects at 64 and 128 MHz. Applied Magn. Reson. 29:5-18, 2005.
Lazovic J, Wrzos HF, Yang QX, Collins CM, Smith MB, Norgren R, Matyas K, Ouyang A. Regional activation in the rat brain during visceral stimulation detected by c-FOS expression and fMRI. Neurogastroenterology and Motility 17:548-556, 2005.
Lazovic J, Stokovic DS, Collins CM, Yang QX, Vaughan JT, Smith MB. Hexagonal zero-mode TEM coil: a single-channel coil design for imaging of multiple small animals. Magn. Reson. Med., 53:1150-1157, 2005.
Collins CM, Liu W, Schreiber W, Yang QX, and Smith MB. Central Brightening Due to Constructive Interference With, Without, and Despite Dielectric Resonance. J. Magn. Reson. Imag. 21:192–196, 2005.
Collins CM, Smith MB, and Turner RW: Model of local temperature changes in brain upon functional activation. J. Appl. Physiol. 97:2051-2055, 2004.
Yang QX, Wang J, Collins CM, Smith MB, Zhang X, Ugurbil K, and Chen W: Phantom Design Method for High-Field MRI Human Systems. Magn. Reson. Med., 52:1016-1020, 2004.
Collins CM, Liu W, Wang JH, Gruetter R, Vaughan JT, Ugurbil K, and Smith MB: Temperature and SAR calculations for a human head within volume and surface coils at 64 and 300 MHz. J. Magn. Reson. Imag., 19:650-656, 2004.
Mosher TJ, Collins CM, Smith HE, Moser LE, Sivarajah RT, Dardzinski BJ, and Smith MB: Effect of gender on in vivo cartilage magnetic resonance imaging T2 mapping. J. Magn. Reson. Imag., 19:323-328, 2004.
Liu W, Collins CM, Delp PJ, and Smith MB: Effects of end-ring/shield configuration on homogeneity and signal-to-noise ratio in a birdcage-type coil loaded with a human head. Magn. Reson. Med., 51:217-221, 2004.
Collins CM and Smith MB: Spatial resolution of numerical models of man and calculated specific absorption rate using the FDTD method: a study at 64 MHz in a magnetic resonance imaging coil. J. Magn. Reson. Imag., 18:383-388, 2003.
Beck B, Plant DH, Grant SC, Thelwall PE, Silver X, Mareci TH, Benveniste H, Smith M, Collins C, Crozier S. Blackband SJ: Progress in High Field MRI at the University of Florida. Magn. Reson. Materials in Physics, Biology and Medicine 13:152-157, 2002.
Alecci M, Collins CM, Wilson J, Liu W, Smith MB, Jezzard P: Theoretical and Experimental Evaluation of Detached Endcaps for 3T Birdcage Coils. Magn. Reson. Med., 49:363-370, 2003.
CollinsCM, YangB, YangQX, and SmithMB: Numerical Calculations of the Static Magnetic Field in Three-Dimensional Multi-Tissue Models of the Human Head. Magn. Reson. Imag., 20:413-424, 2002.
Wang JH, Yang QX, Collins CM, Smith MB, Zhang X, Liu H, Zhu X-H, Adriany G, Ugurbil K, Chen W: The Polarization of the Radio Frequency Field in a Human Head at High Field: a Study with a Quadrature Surface Coil at 7.0 Tesla. Magn. Reson. Med., 48(2):362-369, August 2002.
Chin CL, Collins CM, LiS, DardzinskiBJ, Smith MB: BirdcageBuilder: Design of Specified-Geometry Birdcage Coils with Desired Current Pattern and Resonant Frequency, Concepts in Magn. Reson. B (Magn. Reson. Eng.) 15(2):156-163, June 2002.
Yang QX, Wang JH, Collins CM, Smith MB, Zhang X, Liu H, Michaeli S, Zhu X-H, Adriany G, Vaughan JT, Anderson P, Ugurbil K, Chen W: Analysis of Wave Behavior in Dielectric Samples at High Field. Magn. Reson. Med., 47:982-989, 2002.
Collins CM, Yang QX, Wang JH, Zhu X-H, Adriany G, Michaeli S, Vaughan JT, Zhang X, Liu H, Anderson P, Ugurbil K, Smith MB, and Chen W: Different Excitation and Reception Distributions with a Single-Loop Transmit-Receive Surface Coil Near a Head-Sized Spherical Phantom at 300 MHz. Magn. Reson. Med., 47:1026-1028, 2002.
Vaughan JT, Garwood M, Collins CM, Liu W, DelaBarre L, Kim SG, Adriany G, Andersen P, Merkle H, Goebel R, Smith MB, and Ugurbil K: 7T vs. 4T: RF Power, Homogeneity, and Signal-to-Noise Comparison in Head Images. Magn. Reson. Med., 46:24-30, 2001.
Smith HE, Mosher TJ, Dardzinski BJ, Collins BG, Collins CM, Yang QX, Schmithorst VJ, Smith MB: Spatial Variation in Cartilage T2 of the Knee. J. Magn. Reson. Imag., 14:50-55, 2001.
Alecci M, Collins CM, Smith MB, and Jezzard P: Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties. Magn. Reson. Med., 46:379-385, 2001.
Collins CM and Smith MB: Calculations of B₁ Distribution, SNR, and SAR for a Surface Coil Against an Anatomically-accurate Human Body Model. Magn. Reson. Med., 45:692-699, 2001.
Collins CM and Smith MB: Signal-to-Noise Ratio and Absorbed Power as Functions of Main Magnetic Field Strength and Definition of “90°” RF Pulse for the Head in the Birdcage Coil. Magn. Reson. Med. 45:684-691, 2001.
Collins CM, Li S, Smith MB: SAR and B1 Field Distributions in a Heterogeneous Human Head Model within a Birdcage Coil. Magn. Reson. Med. 40:847-856, 1998.
Strilka RJ, Li S, Martin JT, Collins CM, Smith MB: A numerical study of radiofrequency deposition in a spherical phantom using surface coils. Magn. Reson. Imag. 16(7):787-798, 1998.
Dardzinski BJ, Li S, Collins CM, Williams GD, Smith MB: A birdcage coil tuned by RF shielding for application at 9.4 T. J. Magn. Reson., 131(1):32-8, 1998.
Collins CM, Li S, Yang QX, Smith MB: A Method for Accurate Calculation of B₁ Fields in Three Dimensions: Effects of Shield Geometry on Field Strength and Homogeneity in the Birdcage Coil. J. Magn. Reson., 125:233-241, 1997.
Li S, Collins CM, Dardzinski BJ, Chin C-L, Smith MB: A Method to Create an Optimum Current Distribution and Homogeneous B₁ Field for Elliptical Birdcage Coils. Magn. Reson. Med., 37:600-608, 1997.
Li S, Dardzinski BJ, Collins CM, Yang QX, Smith MB: Three-Dimensional Mapping of the Static Magnetic Field Inside the Human Head. Magn. Reson. Med., 36:705-714, 1996.

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