**E-prints and Preprints**

- P. Chandrasekaran, C. Chen, Y. Liu, S. M. Arshad, C. Crabtree, M. Tong, Y. Han, and R. Ahmad, “Accelerated real-time cine and flow under in-magnet staged exercise,”
*arXiv preprint arXiv:2402.17877*, 2024. - X. Lei, P. Schniter, C. Chen, and R. Ahmad, “Surface coil intensity correction for MRI,”
*arXiv preprint arXiv:2312.00936*, 2023. - M. A. Sultan, C. Chen, Y. Liu, and R. Ahmad, “Deep image prior with structured sparsity (DISCUS) for dynamic MRI reconstruction,”
*arXiv preprint arXiv:2312.00953*, 2023. - S. M. Arshad, L. C. Potter, C. Chen, Y. Liu, P. Chandrasekaran, C. Crabtree, Y. Han, and R. Ahmad, “Motion-robust free-running cardiovascular MRI,”
*arXiv preprint arXiv:2308.02088*, 2023. - S. Liu, M. Shafique, P. Schniter, and R. Ahmad, “MRI recovery with self-calibrated denoisers without fully-sampled data,”
*arXiv preprint arXiv:2304.12890*, 2023. - M. Joshi, A. Pruitt, C. Chen, Y. Liu, and R. Ahmad, “Technical report (v1.0)–Pseudo-random Cartesian sampling for dynamic MRI,”
*arXiv preprint arXiv:2206.03630*, 2022. - C. Chen, Y. Liu, P. Schniter, M. Tong, K. Zareba, O. Simonetti, L. Potter, and R. Ahmad, “OCMR (v1.0)–Open-access multi-coil k-space dataset for cardiovascular magnetic resonance imaging,”
*arXiv preprint arXiv:2008.03410*, 2020.

**Journal Publications**

- C. Chen, Y. Liu, O. P. Simonetti, M. Tong, N. Jin, M. Bacher, P. Speier, and R. Ahmad, “Cardiac and respiratory motion extraction for MRI using Pilot Tone–a patient study,”
*The International Journal of Cardiovascular Imaging*, vol. 40, no. 1, pp. 93–105, 2024. - J. Varghese, N. Jin, D. Giese, C. Chen, Y. Liu, Y. Pan, N. Nair, M. T. Shalaan, M. Khan, M. S. Tong, et al., “Building a comprehensive cardiovascular magnetic resonance exam on a commercial 0.55 T system: A pictorial essay on potential applications,”
*Frontiers in Cardiovascular Medicine*, vol. 10, p. 1120982, 2023. - D. Tucker, S. Zhao, R. Ahmad, and L. C. Potter, “Alias-free arrays,”
*IEEE Signal Processing Letters*, vol. 29, pp. 2457–2461, 2022. - S. K. Shastri, R. Ahmad, C. A. Metzler, and P. Schniter, “Denoising generalized expectation-consistent approximation forMR image recovery,”
*IEEE Journal on Selected Areas in Information Theory*, vol. 3, no. 3, pp. 528–542, 2022. - S. Zhao, R. Ahmad, and L. C. Potter, “Venc design and velocity estimation for phase contrast MRI,”
*IEEE Transactions on Medical Imaging*, vol. 41, no. 12, pp. 3712–3724, 2022. - C. Chen, P. Chandrasekaran, Y. Liu, O. P. Simonetti, M. Tong, and R. Ahmad, “Ensuring respiratory phase consistency to improve cardiac function quantification in real-time CMR,”
*Magnetic Resonance in Medicine*, vol. 87, no. 3, pp. 1595–1604, 2022. - H. Dong, R. Ahmad, R. Miller, and A. Kolipaka, “MR elastography inversion by compressive recovery,”
*Physics in Medicine & Biology*, vol. 66, no. 16, p. 165001, 2021. - D. Cristea, H. Wolfson, R. Ahmad, Y. Twig, P. Kuppusamy, and A. Blank, “Compact electron spin resonance skin oximeter: Properties and initial clinical results,”
*Magnetic Resonance in Medicine*, vol. 85, no. 5, pp. 2915–2925, 2021. - Zhao, L. C. Potter, and R. Ahmad, “High-dimensional fast convolutional framework (HICU) for calibrationless MRI,”
*Magnetic Resonance in Medicine*, vol. 86, no. 3, pp. 1212–1225, 2021. - A. Pruitt, A. Rich, Y. Liu, N. Jin, L. Potter, M. Tong, S. Rajpal, O. Simonetti, and R. Ahmad, “Fully self-gated whole-heart 4D flow imaging from a 5-minute scan,”
*Magnetic Resonance in Medicine*, vol. 85, no. 3, pp. 1222–1236, 2021. - M. A. Bush, Y. Pan, N. Jin, Y. Liu, J. Varghese, R. Ahmad, and O. P. Simonetti, “Prospective correction of patient-specific respiratory motion in myocardial T1 and T2 mapping,”
*Magnetic Resonance in Medicine*, vol. 85, no. 2, pp. 855–867, 2021. - D. A. Komarov, A. Samouilov, R. Ahmad, and J. L. Zweier, “Algebraic reconstruction of 3D spatial EPR images from high numbers of noisy projections: An improved image reconstruction technique for high resolution fast scan EPR imaging,”
*Journal of Magnetic Resonance*, vol. 319, p. 106812, 2020. - J. Varghese, M. Smyke, Y. Pan, S. Rajpal, J. Craft, L. C. Potter, S. V. Raman, R. Ahmad, and O. P. Simonetti, “Patient-adaptive magnetic resonance oximetry: Comparison with invasive catheter measurement of blood oxygen saturation in patients with cardiovascular disease,”
*Journal of Magnetic Resonance Imaging*, vol. 52, no. 5, pp. 1449–1459, 2020. - S. D. Serai, H. H. Hu, R. Ahmad, S. White, A. Pednekar, S. A. Anupindi, and E. Y. Lee, “Newly developed methods for reducing motion artifacts in pediatric abdominal MRI: tips and pearls,”
*American Journal of Roentgenology*, vol. 214, no. 5, pp. 1042–1053, 2020. - A. Rich, M. Gregg, N. Jin, Y. Liu, L. Potter, O. Simonetti, and R. Ahmad, “Cartesian sampling with variable density and adjustable temporal resolution (CAVA),”
*Magnetic Resonance in Medicine*, vol. 83, no. 6, pp. 2015–2025, 2020. - R. Ahmad, C. A. Bouman, G. T. Buzzard, S. Chan, S. Liu, E. T. Reehorst, and P. Schniter, “Plug-and-play methods for magnetic resonance imaging: Using denoisers for image recovery,”
*IEEE Signal Processing Magazine*, vol. 37, no. 1, pp. 105–116, 2020. [long version (arxiv)] - P. Kuppusamy, M. M. Kmiec, D. Tse, J. M. Mast, and R. Ahmad, “Estimation of pO2 histogram from a composite EPR spectrum of multiple random implants,”
*Biomedical Microdevices*, vol. 22, no. 1, p. 3, 2020. - J. Varghese, J. Craft, C. D. Crabtree, Y. Liu, N. Jin, K. Chow, R. Ahmad, and O. P. Simonetti, “Assessment of cardiac function, blood flow and myocardial tissue relaxation parameters at 0.35 T,”
*NMR in Biomedicine*, vol. 33, no. 7, p. e4317, 2020. - A. Rich, L. C. Potter, N. Jin, Y. Liu, O. P. Simonetti, and R. Ahmad, “A Bayesian approach for 4D flow imaging of aortic valve in a single breath-hold,”
*Magnetic Resonance in Medicine*, vol. 81, no. 2, pp. 811–824, 2019. - M. A. Bush, R. Ahmad, N. Jin, Y. Liu, and O. P. Simonetti, “Patient-specific prospective respiratory motion correction for efficient, free-breathing cardiovascular MRI,”
*Magnetic Resonance in Medicine*, vol. 81, no. 6, pp. 3662–3674, 2019. - M. Kmiec, D. Tse, J. Mast, R. Ahmad, and P. Kuppusamy, “Implantable microchip containing oxygen-sensing paramagnetic crystals for long-term, repeated, and multisite in vivo oximetry,”
*Biomedical Microdevices*, vol. 21, no. 71, 2019. - A. A. Pruitt, N. Jin, Y. Liu, O. P. Simonetti, and R. Ahmad, “A method to correct background phase offset for phase-contrast MRI in the presence of steady flow and spatial wrap-around artifact,”
*Magnetic Resonance in Medicine*, vol. 81, no. 4, pp. 2424–2438, 2019. - C. Chen, Y. Liu, P. Schniter, N. Jin, J. Craft, O. Simonetti, and R. Ahmad, “Sparsity adaptive reconstruction for highly accelerated cardiac MRI,”
*Magnetic Resonance in Medicine*, vol. 81, no. 6, pp. 3875–3887, 2019. - O. Zgadzai, Y. Twig, H. Wolfson, R. Ahmad, P. Kuppusamy, and A. Blank, “Electron-spin-resonance dipstick,”
*Analytical Chemistry*, vol. 90, no. 13, pp. 7830–7836, 2018. - A. Samouilov, R. Ahmad, J. Boslett, X. Liu, S. Petryakov, and J. L. Zweier, “Development of a fast-scan EPR imaging system for highly accelerated free radical imaging,”
*Magnetic Resonance in Medicine*, vol. 82, no. 2, pp. 842–853, 2019. - R. Ahmad, H. H. Hu, R. Krishnamurthy, and R. Krishnamurthy, “Reducing sedation for pediatric body MRI using accelerated and abbreviated imaging protocols,”
*Pediatric Radiology*, vol. 48, no. 1, pp. 37–49, 2018. - C. Ebersole, R. Ahmad, A. V. Rich, L. C. Potter, H. Dong, and A. Kolipaka, “A Bayesian method for accelerated magnetic resonance elastography of the liver,”
*Magnetic Resonance in Medicine*, vol. 80, no. 3, pp. 1178–1188, 2018. - J. S. da Silveira, M. Smyke, A. V. Rich, Y. Liu, N. Jin, D. Scandling, J. A. Dickerson, C. E. Rochitte, S. V. Raman, L. C. Potter, R. Ahmad, and O. P. Simonetti, “Quantification of aortic stenosis diagnostic parameters: comparison of fast 3 direction and 1 direction phase contrast CMR and transthoracic echocardiography,”
*Journal of Cardiovascular Magnetic Resonance*, vol. 19, no. 1, p. 35, 2017. - J. Varghese, L. C. Potter, R. LaFountain, X. Pan, S. V. Raman, R. Ahmad, and O. P. Simonetti, “CMR-based blood oximetry via multi-parametric estimation using multiple T2 measurements,”
*Journal of Cardiovascular Magnetic Resonance*, vol. 19, no. 1, p. 88, 2017. - S. T. Ting, R. Ahmad, N. Jin, J. Craft, J. Serafim da Silveira, H. Xue, and O. P. Simonetti, “Fast implementation for compressive recovery of highly accelerated cardiac cine MRI using the balanced sparse model,”
*Magnetic Resonance in Medicine*, vol. 77, no. 4, pp. 1505–1515, 2017. - O. P. Simonetti and R. Ahmad, “Low-field cardiac magnetic resonance imaging: A compelling case for cardiac magnetic resonance’s future,”
*Circulation: Cardiovascular Imaging*, vol. 10, no. 6, p. e005446, 2017. - R. Ahmad, A. Samouilov, and J. L. Zweier, “Accelerated dynamic EPR imaging using fast acquisition and compressive recovery,”
*Journal of Magnetic Resonance*, vol. 273, pp. 105–112, 2016. - A. Rich, L. C. Potter, N. Jin, J. Ash, O. P. Simonetti, and R. Ahmad, “A Bayesian model for highly accelerated phase-contrast MRI,”
*Magnetic Resonance in Medicine*, vol. 76, no. 2, pp. 689–701, 2016. - R. Ahmad, H. Xue, S. Giri, Y. Ding, J. Craft, and O. P. Simonetti, “Variable density incoherent spatiotemporal acquisition (VISTA) for highly accelerated cardiac MRI,”
*Magnetic Resonance in Medicine*, vol. 74, no. 5, pp. 1266–1278, 2015. - R. Ahmad and P. Schniter, “Iteratively reweighted l
_{1}approaches to sparse composite regularization,”*IEEE Transactions on Computational Imaging*, vol. 1, no. 4, pp. 220–235, 2015. [constrained version (arxiv)] - Y. Ding, H. Xue, R. Ahmad, T.-c. Chang, S. T. Ting, and O. P. Simonetti, “Paradoxical effect of the signal-to-noise ratio of GRAPPA calibration lines: A quantitative study,”
*Magnetic Resonance in Medicine*, vol. 74, no. 1, pp. 231–239, 2015. - R. Ahmad, Y. Ding, and O. P. Simonetti, “Edge sharpness assessment by parametric modeling: application to magnetic resonance imaging,”
*Concepts in Magnetic Resonance Part A*, vol. 44, no. 3, pp. 138–149, 2015. - H. Woflson, R. Ahmad, Y. Twig, B. Williams, and A. Blank, “A magnetic resonance probehead for evaluating the level of ionizing radiation absorbed in human teeth,”
*Health Physics*, vol. 108, no. 3, pp. 326–335, 2015. - D. H. Johnson, R. Ahmad, Y. Liu, Z. Chen, A. Samouilov, and J. L. Zweier, “Uniform spinning sampling gradient electron paramagnetic resonance imaging,”
*Magnetic Resonance in Medicine*, vol. 71, no. 2, pp. 893–900, 2014. - H. Wolfson, R. Ahmad, Y. Twig, P. Kuppusamy, and A. Blank, “A miniature electron spin resonance probehead for transcutaneous oxygen monitoring,”
*Applied Magnetic Resonance*, vol. 45, no. 10, pp. 955–967, 2014. - D. H. Johnson, R. Ahmad, G. He, A. Samouilov, and J. L. Zweier, “Compressed sensing of spatial electron paramagnetic resonance imaging,”
*Magnetic Resonance in Medicine*, vol. 72, no. 3, pp. 893–901, 2014. - J. A. Bender, R. Ahmad, and O. P. Simonetti, “The importance of k-space trajectory on off-resonance artifact in segmented echo-planar imaging,”
*Concepts in Magnetic Resonance Part A*, vol. 42, no. 2, pp. 23–31, 2013. - F. Golub, L. C. Potter, J. N. Ash, A. Blank, and R. Ahmad, “Estimation of spin-echo relaxation time,”
*Journal of Magnetic Resonance*, vol. 237, pp. 17–22, 2013. - R. Ahmad, S. Som, D. H. Johnson, J. L. Zweier, P. Kuppusamy, and L. C. Potter, “Multisite EPR oximetry from multiple quadrature harmonics,”
*Journal of Magnetic Resonance*, vol. 214, pp. 135–143, 2012. - J. Palmer, L. C. Potter, D. H. Johnson, J. L. Zweier, and R. Ahmad, “Dual-scan acquisition for accelerated continuous-wave EPR oximetry,”
*Journal of Magnetic Resonance*, vol. 222, pp. 53–58, 2012. - Y. Ding, H. Xue, R. Ahmad, S. T. Ting, and O. P. Simonetti, “SC-GRAPPA: Self-constraint noniterative GRAPPA reconstruction with closed-form solution,”
*Medical Physics*, vol. 39, no. 12, pp. 7686–7693, 2012. - R. Ahmad, L. C. Potter, and V. V. Khramtsov, “Spectral modeling for accelerated pH spectroscopy using EPR,”
*Journal of Magnetic Resonance*, vol. 218, pp. 86–92, 2012. - J. Palmer, L. C. Potter, and R. Ahmad, “Optimization of magnetic field sweep and field modulation amplitude for continuous-wave EPR oximetry,”
*Journal of Magnetic Resonance*, vol. 209, no. 2, pp. 337–340, 2011. - R. Ahmad and P. Kuppusamy, “Theory, instrumentation, and applications of electron paramagnetic resonance oximetry,”
*Chemical Reviews*, vol. 110, no. 5, pp. 3212–3236, 2010. - R. Ahmad, S. Som, E. Kesselring, P. Kuppusamy, J. L. Zweier, and L. C. Potter, “Digital detection and processing of multiple quadrature harmonics for EPR spectroscopy,”
*Journal of Magnetic Resonance*, vol. 207, no. 2, pp. 322–331, 2010. - R. Ahmad, G. Caia, L. C. Potter, S. Petryakov, P. Kuppusamy, and J. L. Zweier, “In vivo multisite oximetry using EPR–NMR coimaging,”
*Journal of Magnetic Resonance*, vol. 207, no. 1, pp. 69–77, 2010. - S. Som, L. C. Potter, R. Ahmad, D. S. Vikram, and P. Kuppusamy, “EPR oximetry in three spatial dimensions using sparse spin distribution,”
*Journal of Magnetic Resonance*, vol. 193, no. 2, pp. 210–217, 2008. - D. S. Vikram, R. Ahmad, B. K. Rivera, and P. Kuppusamy, “Mapping of oxygen concentration in biological samples using EPR imaging,”
*Israel Journal of Chemistry*, vol. 48, no. 1, pp. 39–43, 2008. - D. S. Vikram, R. Ahmad, R. P. Pandian, S. Petryakov, and P. Kuppusamy, “Evaluation of oxygen-response times of phthalocyanine-based crystalline paramagnetic spin probes for EPR oximetry,”
*Journal of Magnetic Resonance*, vol. 193, no. 1, pp. 127–132, 2008. - R. Ahmad, D. S. Vikram, L. C. Potter, and P. Kuppusamy, “Estimation of mean and median pO2 values for a composite EPR spectrum,”
*Journal of Magnetic Resonance*, vol. 192, no. 2, pp. 269–274, 2008. - R. Ahmad, B. Clymer, D. S. Vikram, Y. Deng, H. Hirata, J. L. Zweier, and P. Kuppusamy, “Enhanced resolution for EPR imaging by two-step deblurring,”
*Journal of Magnetic Resonance*, vol. 184, no. 2, pp. 246–257, 2007. - R. Ahmad, Y. Deng, D. S. Vikram, B. Clymer, P. Srinivasan, J. L. Zweier, and P. Kuppusamy, “Quasi Monte Carlo-based isotropic distribution of gradient directions for improved reconstruction quality of 3D EPR imaging,”
*Journal of Magnetic Resonance*, vol. 184, no. 2, pp. 236–245, 2007. - S. Som, L. C. Potter, R. Ahmad, and P. Kuppusamy, “A parametric approach to spectral–spatial EPR imaging,”
*Journal of Magnetic Resonance*, vol. 186, no. 1, pp. 1–10, 2007. - R. Ahmad, D. S. Vikram, B. Clymer, L. C. Potter, Y. Deng, P. Srinivasan, J. L. Zweier, and P. Kuppusamy, “Uniform distribution of projection data for improved reconstruction quality of 4D EPR imaging,”
*Journal of Magnetic Resonance*, vol. 187, no. 2, pp. 277–287, 2007. - D. S. Vikram, A. Bratasz, R. Ahmad, and P. Kuppusamy, “A comparative evaluation of EPR and oxylite oximetry using a random sampling of pO2 in a murine tumor,”
*Radiation Research*, vol. 168, no. 3, pp. 308–315, 2007. - Y. Deng, R. P. Pandian, R. Ahmad, P. Kuppusamy, and J. L. Zweier, “Application of magnetic field over-modulation for improved EPR linewidth measurements using probes with Lorentzian lineshape,”
*Journal of Magnetic Resonance*, vol. 181, no. 2, pp. 254–261, 2006. - R. Ahmad, B. Clymer, Y. Deng, G. He, D. Vikram, P. Kuppusamy, and J. L. Zweier, “Optimization of data acquisition for EPR imaging,”
*Journal of Magnetic Resonance*, vol. 179, no. 2, pp. 263–272, 2006. - R. Ahmad, D. S. Vikram, S. Petryakov, Y. Deng, J. L. Zweier, P. Kuppusamy, and B. Clymer, “Automated on-the-fly detection and correction procedure for EPR imaging data acquisition,”
*Magnetic Resonance in Medicine*, vol. 56, no. 3, pp. 644–653, 2006.

**Conference Publications**

- M. Bendel, R. Ahmad, and P. Schniter, “A regularized conditional GAN for posterior sampling in image recovery problems,”
*Advances in Neural Information Processing Systems*, vol. 36, 2024. - J. Wen, R. Ahmad, and P. Schniter, “A conditional normalizing flow for accelerated multi-coil MR imaging,”
*Proceedings of Machine Learning Research*, vol. 202, p. 36926, 2023. - S. K. Shastri, R. Ahmad, C. A. Metzler, and P. Schniter, “Expectation consistent plug-and-play for MRI,” in
*International Conference on Acoustics, Speech and Signal Processing (ICASSP)*, pp. 8667–8671, IEEE, 2022. - S. Liu, P. Schniter, and R. Ahmad, “MRI recovery with a self-calibrated denoiser,” in
*International Conference on Acoustics, Speech and Signal Processing (ICASSP)*, pp. 1351–1355, IEEE, 2022. - S. Zhao, R. Ahmad, and L. C. Potter, “Maximizing unambiguous velocity range in phase-contrast MRI with multipoint encoding,” in
*19th International Symposium on Biomedical Imaging (ISBI)*, pp. 1–5, IEEE, 2022. - S. Sarkar, R. Ahmad, and P. Schniter, “MRI image recovery using damped denoising vector AMP,” in
*ICASSP 2021 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)*, pp. 8108–8112, IEEE, 2021. - S. Zhao, L. C. Potter, and R. Ahmad, “Calibrationless MRI reconstruction with a plug-in denoiser,” in
*2021 IEEE 18thInternational Symposium on Biomedical Imaging (ISBI)*, pp. 1846–1849, IEEE, 2021. - S. K. Shastri, R. Ahmad, and P. Schniter, “Autotuning plug-and-play algorithms for MRI,” in
*2020 54th Asilomar Conference on Signals, Systems, and Computers*, pp. 1400–1404, IEEE, 2020. - S. Liu, E. Reehorst, P. Schniter, and R. Ahmad, “Free-breathing cardiovascular MRI using a plug-and-play method with learned denoiser,” in
*2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI)*, pp. 1748–1751, IEEE, 2020. - S. Zhao, L. C. Potter, K. Lee, and R. Ahmad, “Convolutional framework for accelerated magnetic resonance imaging,” in
*2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI)*, pp. 1–4, IEEE, 2020. - C. Chen, Y. Liu, O. P. Simonetti, and R. Ahmad, “Automatic extraction and sign determination of respiratory signal in real-time cardiac magnetic resonance imaging,” in
*2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI)*,pp. 1–4, IEEE, 2020. - A. Rich, L. C. Potter, J. N. Ash, and R. Ahmad, “Factor graphs for inverse problems: Accelerated phase contrast magnetic resonance imaging,” in
*2015 IEEE International Conference on Image Processing (ICIP)*, pp. 1026–1030, IEEE, 2015. - H. Wolfson, R. Ahmad, Y. Twig, A. Blank, and P. Kuppusamy, “A hand-held EPR scanner for transcutaneous oximetry,” in
*Medical Imaging 2015: Biomedical Applications in Molecular, Structural, and Functional Imaging*, vol. 9417, p. 941706, International Society for Optics and Photonics, SPIE, 2015. - R. Ahmad, C. Austin, and L. C. Potter, “Toeplitz embedding for fast iterative regularized imaging,” in
*Algorithms for Synthetic Aperture Radar Imagery XVIII*, vol. 8051, p. 80510E, International Society for Optics and Photonics, SPIE, 2011. - R. Ahmad, P. Kuppusamy, and L. C. Potter, “Nested uniform sampling for multiresolution 3-D tomography,” in
*2010 IEEE International Conference on Acoustics, Speech and Signal Processing*, pp. 461–464, IEEE, 2010.