
Andrew S. Nencka, PhD
Associate Director
Contact Information
Education
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
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
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Optimization of hyperparameters for SMS reconstruction.
(Muftuler LT, Arpinar VE, Koch K, Bhave S, Yang B, Kaushik S, Banerjee S, Nencka A.) Magn Reson Imaging. 2020 11;73:91-103 PMID: 32835848 SCOPUS ID: 2-s2.0-85089907300 08/25/2020
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(Rivera Bonet CN, Hwang G, Hermann B, Struck AF, J Cook C, A Nair V, Mathis J, Allen L, Almane DN, Arkush K, Birn R, Conant LL, DeYoe EA, Felton E, Maganti R, Nencka A, Raghavan M, Shah U, Sosa VN, Ustine C, Prabhakaran V, Binder JR, Meyerand ME.) Epilepsy Behav. 2020 09;110:107172 PMID: 32554180 PMCID: PMC7483612 SCOPUS ID: 2-s2.0-85086476142 06/20/2020
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Longitudinal white-matter abnormalities in sports-related concussion: A diffusion MRI study.
(Wu YC, Harezlak J, Elsaid NMH, Lin Z, Wen Q, Mustafi SM, Riggen LD, Koch KM, Nencka AS, Meier TB, Mayer AR, Wang Y, Giza CC, DiFiori JP, Guskiewicz KM, Mihalik JP, LaConte SM, Duma SM, Broglio SP, Saykin AJ, McCrea MA, McAllister TW.) Neurology. 2020 08 18;95(7):e781-e792 PMID: 32641518 PMCID: PMC7605507 SCOPUS ID: 2-s2.0-85089787382 07/10/2020
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Generalized simultaneous multi-orientation 2D imaging.
(Mickevicius NJ, Nencka AS, Paulson ES.) Magn Reson Med. 2020 08;84(2):847-856 PMID: 31872496 SCOPUS ID: 2-s2.0-85077067040 12/25/2019
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(Nencka AS.) J Magn Reson Imaging. 2020 07;52(1):255-256 PMID: 31922318 SCOPUS ID: 2-s2.0-85078051911 01/11/2020
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(Bobholz SA, Lowman AK, Barrington A, Brehler M, McGarry S, Cochran EJ, Connelly J, Mueller WM, Agarwal M, O'Neill D, Nencka AS, Banerjee A, LaViolette PS.) Tomography. 2020 06;6(2):160-169 PMID: 32548292 PMCID: PMC7289245 SCOPUS ID: 2-s2.0-85086686895 06/18/2020
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(Koch KM, Bhave S, Kaushik SS, Nencka AS, Budde MD.) Eur Spine J. 2020 05;29(5):1071-1077 PMID: 31832875 PMCID: PMC7225051 SCOPUS ID: 2-s2.0-85076835282 12/14/2019
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Network, clinical and sociodemographic features of cognitive phenotypes in temporal lobe epilepsy.
(Hermann B, Conant LL, Cook CJ, Hwang G, Garcia-Ramos C, Dabbs K, Nair VA, Mathis J, Bonet CNR, Allen L, Almane DN, Arkush K, Birn R, DeYoe EA, Felton E, Maganti R, Nencka A, Raghavan M, Shah U, Sosa VN, Struck AF, Ustine C, Reyes A, Kaestner E, McDonald C, Prabhakaran V, Binder JR, Meyerand ME.) Neuroimage Clin. 2020;27:102341 PMID: 32707534 PMCID: PMC7381697 SCOPUS ID: 2-s2.0-85088252788 07/25/2020
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(Pahapill PA, Chen G, Arocho-Quinones EV, Nencka AS, Li SJ.) PLoS One. 2020;15(2):e0228306 PMID: 32074111 PMCID: PMC7029839 SCOPUS ID: 2-s2.0-85079521450 02/20/2020
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Brain aging in temporal lobe epilepsy: Chronological, structural, and functional.
(Hwang G, Hermann B, Nair VA, Conant LL, Dabbs K, Mathis J, Cook CJ, Rivera-Bonet CN, Mohanty R, Zhao G, Almane DN, Nencka A, Felton E, Struck AF, Birn R, Maganti R, Humphries CJ, Raghavan M, DeYoe EA, Bendlin BB, Prabhakaran V, Binder JR, Meyerand ME.) Neuroimage Clin. 2020;25:102183 PMID: 32058319 PMCID: PMC7016276 SCOPUS ID: 2-s2.0-85079141146 02/15/2020
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Just Another CNN in K-space to De-Alias N Individual Excited Locations Simultaneously (JACKDANIELS)
(Sampada Bhave, Volkan E Arpinar, Nikolai Mickevicius, Kevin M. Koch, Andrew S Nencka.) Proc. ISMRM Data Sampling and Reconstruction Workshop. (2020): 53 01/26/2020
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(Brett BL, Wu YC, Mustafi SM, Saykin AJ, Koch KM, Nencka AS, Giza CC, Goldman J, Guskiewicz KM, Mihalik JP, Duma SM, Broglio SP, McAllister TW, McCrea MA, Meier TB.) Front Neurol. 2019;10:1345 PMID: 32038451 PMCID: PMC6990104 SCOPUS ID: 2-s2.0-85079132454 02/11/2020