
Andrew S. Nencka, PhD
Associate Professor; Associate Director, Center for Imaging Research (CIR); Section of Imaging Research, Division of Imaging Sciences
Locations
- Medical College of Wisconsin
Department of Radiology
Contact Information
Education
BS, Physics & Mathematics, Marquette University, Milwaukee, WI, 2004
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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(Chu DY, Adluru N, Nair VA, Choi T, Adluru A, Garcia-Ramos C, Dabbs K, Mathis J, Nencka AS, Gundlach C, Conant L, Binder JR, Meyerand ME, Alexander AL, Struck AF, Hermann B, Prabhakaran V.) Epilepsia. 2023 Sep;64(9):2484-2498 PMID: 37376741 SCOPUS ID: 2-s2.0-85164792241 06/28/2023
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(Pahapill PA, Chen G, Arocho-Quinones EV, Nencka AS.) Neuromodulation. 2023 Jul;26(5):1009-1014 PMID: 37204362 SCOPUS ID: 2-s2.0-85159401230 05/19/2023
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(Garcia-Ramos C, Adluru N, Chu DY, Nair V, Adluru A, Nencka A, Maganti R, Mathis J, Conant LL, Alexander AL, Prabhakaran V, Binder JR, Meyerand ME, Hermann B, Struck AF.) Cereb Cortex. 2023 Jun 08;33(12):8056-8065 PMID: 37067514 PMCID: PMC10267614 SCOPUS ID: 2-s2.0-85163480791 04/18/2023
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Development and Stability Analysis of Carpal Kinematic Metrics from 4D Magnetic Resonance Imaging.
(Sharafi A, Nencka AS, Koch KM.) ArXiv. 2023 May 25 PMID: 37292477 PMCID: PMC10246087 06/09/2023
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(Pommy J, Conant L, Butts AM, Nencka A, Wang Y, Franczak M, Glass-Umfleet L.) Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2023 Jan 17:1-20 PMID: 36648118 SCOPUS ID: 2-s2.0-85146479741 01/18/2023
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(Koch KM, Nencka AS, Klein A, Wang M, Kurpad S, Vedantam A, Budde M.) Front Neurol. 2023;14:1172833 PMID: 37273696 PMCID: PMC10236479 SCOPUS ID: 2-s2.0-85161052826 06/05/2023
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(Duenweg SR, Brehler M, Bobholz SA, Lowman AK, Winiarz A, Kyereme F, Nencka A, Iczkowski KA, LaViolette PS.) PLoS One. 2023;18(3):e0278084 PMID: 36928230 PMCID: PMC10019669 SCOPUS ID: 2-s2.0-85150250210 03/18/2023
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(Peterson KJ, Simpson MT, Drezdzon MK, Szabo A, Ausman RA, Nencka AS, Knechtges PM, Peterson CY, Ludwig KA, Ridolfi TJ.) J Gastrointest Surg. 2023 Jan;27(1):122-130 PMID: 36271199 SCOPUS ID: 2-s2.0-85140356180 10/23/2022
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(Reiter K, Butts AM, Janecek JK, Correro AN, Nencka A, Agarwal M, Franczak M, Glass Umfleet L.) Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2022 Dec 26:1-17 PMID: 36573001 SCOPUS ID: 2-s2.0-85145338983 12/28/2022
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(Brett BL, Walton SR, Meier TB, Nencka AS, Powell JR, Giovanello KS, Guskiewicz KM, McCrea MA.) J Neurotrauma. 2022 Apr;39(7-8):497-507 PMID: 35044240 PMCID: PMC8978573 SCOPUS ID: 2-s2.0-85128039718 01/20/2022
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Dynamic tracking of scaphoid, lunate, and capitate carpal bones using four-dimensional MRI.
(Zarenia M, Arpinar VE, Nencka AS, Muftuler LT, Koch KM.) PLoS One. 2022;17(6):e0269336 PMID: 35653348 PMCID: PMC9162359 SCOPUS ID: 2-s2.0-85131243073 06/03/2022
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(Franczak S, Pommy J, Minor G, Zolliecoffer C, Bhalla M, Agarwal M, Nencka A, Wang Y, Klein A, O'Neill D, Henry J, Umfleet G.) Journal of Alzheimer's Disease Reports. 2022;6(1):493-501 SCOPUS ID: 2-s2.0-85136808060 01/01/2022