Radiology

Radiology

Andrew S. Nencka, PhD

Andrew S. Nencka, PhD

Associate Director

Contact Information

Education

PhD, Biophysics, Medical College of Wisconsin, Milwaukee, WI, 2009
BS, Physics & Mathematics, Marquette University, Milwaukee, WI, 2004

Research Experience

  • Data Interpretation, Statistical
  • Echo-Planar Imaging
  • Image Enhancement
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging
  • Models, Statistical
  • Monte Carlo Method
  • Regression Analysis

Leadership Positions

  • Associate Director, Center for Imaging Research, 2016-Present
  • Chair, Faculty IT Committee, 2014-2016
  • Chair, Research MRI Safety Committee, 2012-Present
  • Secretary, Faculty IT Committee, 2016-Present

Research Interests

Image Acquisition Acceleration

One aspect of my research work has been to leverage the phase of acquired images, along with varying receive coil sensitivities, to further spatially encode the acquired data. With the assumption of real-valued images—an assumption often made for partial Fourier image reconstruction—this insight theoretically enables acceleration factors of 2N for an array of N coils. We have used this technology to implement a parallel slice acquisition method that simultaneously excites an array of slices with varying magnetization phase such that the magnetization phase and receive coil sensitivity profiles can be used to unalias the acquired slices. We have also used this technology to acquire and unalias accelerated single-slice images acquired with a single-channel body receiver coil.

Fast MR Relaxometry

Image acceleration techniques have enabled the development of a fast relaxometry pulse sequence, which we have named the gradient-recalled echo, asymmetric spin echo (GREASE) pulse sequence. The pulse sequence, including six echo-planar imaging readouts, two 90-degree excitation pulses, and two 180-degree refocusing pulses in each repetition, allows the computation of T1, T2, and T2* with each repetition. The acceleration techniques of GRAPPA and partial Fourier acquisition in the echo-planar imaging readouts reduce the duration of the imaging readout train so that signal decay does not eliminate the needed signal in later echoes. Thus, the relaxivity values for a single slice of 2 mm isotropic resolution can be acquired in less than 300 ms with this sequence. Further, the nearly simultaneous acquisition of the six images, the identical echo-planar imaging readouts, and the usage of the six images from each repetition for the estimation of relaxivity parameters allow the perfect coregistration of the computed maps.             

Publications

  • Cerebral blood flow in acute concussion: preliminary ASL findings from the NCAA-DoD CARE consortium.

    (Wang Y, Nencka AS, Meier TB, Guskiewicz K, Mihalik JP, Alison Brooks M, Saykin AJ, Koch KM, Wu YC, Nelson LD, McAllister TW, Broglio SP, McCrea MA.) Brain Imaging Behav. 2019 Oct;13(5):1375-1385 PMID: 30159767 SCOPUS ID: 2-s2.0-85053283280 08/31/2018

  • Prevalence of Potentially Clinically Significant Magnetic Resonance Imaging Findings in Athletes with and without Sport-Related Concussion.

    (Klein AP, Tetzlaff JE, Bonis JM, Nelson LD, Mayer AR, Huber DL, Harezlak J, Mathews VP, Ulmer JL, Sinson GP, Nencka AS, Koch KM, Wu YC, Saykin AJ, DiFiori JP, Giza CC, Goldman J, Guskiewicz KM, Mihalik JP, Duma SM, Rowson S, Brooks A, Broglio SP, McAllister T, McCrea MA, Meier TB.) J Neurotrauma. 2019 Jun;36(11):1776-1785 PMID: 30618331 PMCID: PMC6551984 SCOPUS ID: 2-s2.0-85066742597 01/09/2019

  • Resting-state functional connectivity after concussion is associated with clinical recovery.

    (Kaushal M, España LY, Nencka AS, Wang Y, Nelson LD, McCrea MA, Meier TB.) Hum Brain Mapp. 2019 03;40(4):1211-1220 PMID: 30451340 PMCID: PMC6365215 SCOPUS ID: 2-s2.0-85056732323 11/20/2018

  • Effective Connectivity Within the Default Mode Network in Left Temporal Lobe Epilepsy: Findings from the Epilepsy Connectome Project.

    (Cook CJ, Hwang G, Mathis J, Nair VA, Conant LL, Allen L, Almane DN, Birn R, DeYoe EA, Felton E, Forseth C, Humphries CJ, Kraegel P, Nencka A, Nwoke O, Raghavan M, Rivera-Bonet C, Rozman M, Tellapragada N, Ustine C, Ward BD, Struck A, Maganti R, Hermann B, Prabhakaran V, Binder JR, Meyerand ME.) Brain Connect. 2019 03;9(2):174-183 PMID: 30398367 PMCID: PMC6444922 SCOPUS ID: 2-s2.0-85063100708 11/07/2018

  • Acute White-Matter Abnormalities in Sports-Related Concussion: A Diffusion Tensor Imaging Study from the NCAA-DoD CARE Consortium.

    (Mustafi SM, Harezlak J, Koch KM, Nencka AS, Meier TB, West JD, Giza CC, DiFiori JP, Guskiewicz KM, Mihalik JP, LaConte SM, Duma SM, Broglio SP, Saykin AJ, McCrea M, McAllister TW, Wu YC.) J Neurotrauma. 2018 11 15;35(22):2653-2664 PMID: 29065805 PMCID: PMC6238613 SCOPUS ID: 2-s2.0-85053645863 10/27/2017

  • Stability of MRI metrics in the advanced research core of the NCAA-DoD concussion assessment, research and education (CARE) consortium.

    (Nencka AS, Meier TB, Wang Y, Muftuler LT, Wu YC, Saykin AJ, Harezlak J, Brooks MA, Giza CC, Difiori J, Guskiewicz KM, Mihalik JP, LaConte SM, Duma SM, Broglio S, McAllister T, McCrea MA, Koch KM.) Brain Imaging Behav. 2018 Aug;12(4):1121-1140 PMID: 29064019 PMCID: PMC6445663 SCOPUS ID: 2-s2.0-85032009818 10/25/2017

  • Quantitative Susceptibility Mapping after Sports-Related Concussion.

    (Koch KM, Meier TB, Karr R, Nencka AS, Muftuler LT, McCrea M.) AJNR Am J Neuroradiol. 2018 07;39(7):1215-1221 PMID: 29880474 PMCID: PMC6055518 SCOPUS ID: 2-s2.0-85049830789 06/09/2018

  • Functional connectivity density mapping: comparing multiband and conventional EPI protocols.

    (Cohen AD, Tomasi D, Shokri-Kojori E, Nencka AS, Wang Y.) Brain Imaging Behav. 2018 Jun;12(3):848-859 PMID: 28676985 SCOPUS ID: 2-s2.0-85021816914 07/06/2017

  • Off-resonance based assessment of metallic wear debris near total hip arthroplasty.

    (Koch KM, Koff MF, Bauer TW, Shah PH, Nencka AS, Sivaram Kaushik S, Potter HG.) Magn Reson Med. 2018 03;79(3):1628-1637 PMID: 28643347 PMCID: PMC5741538 SCOPUS ID: 2-s2.0-85021256752 06/24/2017

  • Multiband multi-echo simultaneous ASL/BOLD for task-induced functional MRI.

    (Cohen AD, Nencka AS, Wang Y.) PLoS One. 2018;13(2):e0190427 PMID: 29389985 PMCID: PMC5794066 SCOPUS ID: 2-s2.0-85041307092 02/02/2018

  • Image processing and analysis methods for the Adolescent Brain Cognitive Development Study

    (Donald J Hagler Jr., Sean N. Hatton, Carolina Makowski, M. Daniela Cornejo, Damien A. Fair, Anthony Steven Dick, Matthew T. Sutherland, B.J. Casey, Deanna M. Barch, Michael P. Harms, Richard Watts, James M. Bjork, Hugh P. Garavan, Laura Hilmer, Christopher J. Pung, Chelsea S. Sicat, Joshua Kuperman, Hauke Bartsch, Feng Xue, Mary M. Heitzeg, Angela R. Laird, Thanh T. Trinh, Raul Gonzalez, Susan F. Tapert, Michael C. Riedel, Lindsay M. Squeglia, Luke W. Hyde, Monica D. Rosenberg, Eric A. Earl, Katia D. Howlett, Fiona C. Baker, Mary Soules, Jazmin Diaz, Octavio Ruiz de Leon, Wesley K. Thompson, Michael C. Neale, Megan Herting, Elizabeth R. Sowell, Ruben P. Alvarez, Samuel W. Hawes, Mariana Sanchez, Jerzy Bodurka, Florence J. Breslin, Amanda Sheffield Morris, Martin P. Paulus, W. Kyle Simmons, Jonathan R. Polimeni, Andre van der Kouwe, Andrew S. Nencka, Kevin M. Gray, Carlo Pierpaoli, John A. Matochik, Antonio Noronha, Will M. Aklin, Kevin Conway, Meyer Glantz, Elizabeth Hoffman, Roger Little, Marsha Lopez, Vani Pariyadath, Susan R.B. Weiss, Dana L. Wolff-Hughes, Rebecca DelCarmen-Wiggins, Sarah W. Feldstein Ewing, Oscar Miranda-Dominguez, Bonnie J. Nagel, Anders J. Perrone, Darrick T. Sturgeon, Aimee Goldstone, Adolf Pfefferbaum, Kilian M. Pohl, Devin Prouty, Kristina Uban, Susan Y. Bookheimer, Mirella Dapretto, Adriana Galvan, Kara Bagot, Jay Giedd, M. Alejandra Infante, Joanna Jacobus, Kevin Patrick, Paul D. Shilling, Rahul Desikan, Yi Li, Leo Sugrue, Marie T. Banich, Naomi Friedman, John K. Hewitt, Christian Hopfer, Joseph Sakai, Jody Tanabe, Linda B. Cottler, Sara Jo Nixon, Linda Chang, Christine Cloak, Thomas Ernst, Gloria Reeves, David N. Kennedy, Steve Heeringa, Scott Peltier, John Schulenberg, Chandra Sripada, Robert A. Zucker, William G. Iacono, Monica Luciana, Finnegan J. Calabro, Duncan B. Clark, David A. Lewis, Beatriz Luna, Claudiu Schirda, Tufikameni Brima, John J. Foxe, Edward G. Freedman, Daniel W. Mruzek, Michael J. Mason, Rebekah Huber, Erin McGlade, Andrew Prescot, Perry F. Renshaw, Deborah A. Yurgelun-Todd, Nicholas A Allgaier, Julie A. Dumas, Masha Ivanova, Alexandra Potter, Paul Florsheim, Christine Larson, Krista Lisdahl, Michael E. Charness, Bernard Fuemmeler, John M. Hettema, Joel Steinberg, Andrey P. Anokhin, Paul Glaser, Andrew C. Heath, Pamela A. Madden, Arielle Baskin-Sommers, R. Todd Constable, Steven J. Grant, Gayathri J. Dowling, Sandra A. Brown, Terry L. Jernigan, Anders M. Dale.) biorxiv (preprint). https://doi.org/10.1101/457739 03/18/2019

  • Build-A-FLAIR: Synthetic T2-FLAIR Contrast Generation through Physics Informed Deep Learning

    (Andrew S. Nencka, Andrew Klein, Kevin M. Koch, Sean D. McGarry, Peter S. LaViolette, Eric S. Paulson, Nikolai J. Mickevicius, L. Tugan Muftuler, Brad Swearingen, Michael A. McCrea.) arxiv.org. Nencka AS, Klein A, Koch KM, McGarry SD, LaViolette PS, Paulson ES, Mickevicius NJ, Muftuler LT, Swearingen B, McCrea MA. Build-A-FLAIR: Synthetic T2 Contrast Generation through Physics Informed Deep Learning. arXiv.org (2019): 1901.04871. 01/15/2019