Kasra Naftchi-Ardebili

All Publications

• Rapid optimization of focused ultrasound for complex targeting with phased array transducers and precomputed propagation operators. Physics in medicine and biology Hasslberger, M. V., Abraham, M. G., Naftchi-Ardebili, K., Paulus, A. H., Butts Pauly, K. 2026

  Abstract

  Low-intensity focused ultrasound has emerged as a versatile tool for various applications including noninvasive neuromodulation and blood-brain barrier (BBB) opening. To achieve precise individual targeting, phase aberration correction (PAC) is essential to compensate for the heterogeneities introduced by the skull. Traditional methods for PAC are restricted to single point-based targets, resulting in elongated, cigar-shaped focal beams that often fail to align with the geometry of the intended target. Additionally, these approaches demand lengthy simulation times, making the simultaneous sonication of multiple targets within a reasonable timeframe infeasible. This work introduces real-time optimization-based sonication of volumetric brain targets. By leveraging a pair of linear phased array transducers aligned orthogonally over the skull, the approach is capable of optimizing phase and amplitude parameters within seconds to focus acoustic pressure at multiple targets inside target volumes while limiting potential off-target activation. Three brain areas were targeted under different orthogonal transducer alignments, enforcing the desired intracranial peak pressure at a minimum of three target points in each region. Further results demonstrate the sensitivity of transducer displacements, particularly with translational and rotational misalignments. A ray tracing correction scheme was employed, restoring the peak pressure at the intended target region while keeping the increase in off-target pressure below 20%. Overall, these advancements hold promise for enhancing targeting in Focused Ultrasound-guided BBB opening and neuromodulatory applications, expanding the utility of ultrasound in clinical and experimental settings.

  View details for DOI 10.1088/1361-6560/ae3afe

  View details for PubMedID 41558167

• A deep-learning model for one-shot transcranial ultrasound simulation and phase aberration correction. Medical physics Naftchi-Ardebili, K., Singh, K., Popelka, G. R., Pauly, K. B. 2026; 53 (1): e70259

  Abstract

  Transcranial ultrasound is a promising non-invasive neuromodulation technique with applications, including neuronal activity modulation, blood-brain barrier opening, targeted drug delivery, and thermal ablation. Its ability to deliver focused ultrasound waves to precise brain regions has led to over 50 clinical trials targeting conditions such as opioid addiction, Alzheimer's disease, dementia, epilepsy, and glioblastoma. However, skull heterogeneity complicates accurate focal spot prediction and energy delivery, requiring rapid yet precise phase aberration correction in clinical workflows.To address the trade-off between computational efficiency and accuracy in current focus prediction methods, we introduce TUSNet, a deep learning framework for rapid and accurate transcranial ultrasound pressure field and phase aberration correction computation.TUSNet, an end-to-end neural network, was trained to predict both 2D transcranial ultrasound pressure fields and phase corrections. TUSNet was trained on 180432 synthetic skull Computed Tomography (CT) segments, and tested on 1232 real skull CT segments. Its performance was benchmarked against k-Wave, a MATLAB-based acoustic simulation package, evaluating computation speed, focal spot accuracy, phase correction accuracy, and pressure magnitude estimation.TUSNet computed pressure fields and phase corrections in 21 ms, which is over 1200 × $\times$ faster than k-Wave, while achieving 98.3% accuracy in peak pressure magnitude estimation and a mean focal positioning error of only 0.18 mm relative to k-Wave ground truth. End-to-end training took approximately 8 h on 4x NVIDIA A100 80 GB GPUs.TUSNet demonstrates that deep learning can provide accurate and rapid estimates of phase aberrations and transcranial pressure fields, offering a promising direction for accelerating ultrasound treatment planning. While the present validation is based on simulated, noise-free ultrasound fields, the results establish a foundation that future experimental studies can build on to assess performance under real-world clinical conditions.

  View details for DOI 10.1002/mp.70259

  View details for PubMedID 41474058

  View details for PubMedCentralID PMC12754752

• Biophysical effects and neuromodulatory dose of transcranial ultrasonic stimulation. Brain stimulation Nandi, T., Kop, B. R., Naftchi-Ardebili, K., Stagg, C. J., Pauly, K. B., Verhagen, L. 2025

  Abstract

  Transcranial ultrasonic stimulation (TUS) has the potential to usher in a new era for human neuroscience by allowing spatially precise and high-resolution non-invasive targeting of both deep and superficial brain regions. Currently, fundamental research on the mechanisms of interaction between ultrasound and neural tissues is progressing in parallel with application-focused research. However, a major hurdle in the wider use of TUS is the selection of optimal parameters to enable safe and effective neuromodulation in humans. In this paper, we will discuss the major factors that determine the efficacy of TUS. We will discuss the thermal and mechanical biophysical effects of ultrasound, which underlie its biological effects, in the context of their relationships with tunable parameters. Based on this knowledge of biophysical effects, and drawing on concepts from radiotherapy, we propose a framework for conceptualising TUS dose.

  View details for DOI 10.1016/j.brs.2025.02.019

  View details for PubMedID 40054576

• Focal Volume, Acoustic Radiation Force, and Strain in Two-Transducer Regimes IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL Naftchi-Ardebili, K., Menz, M. D., Salahshoor, H., Popelka, G. R., Baccus, S. A., Pauly, K. 2024; 71 (10): 1199-1216

  Abstract

  Transcranial ultrasound stimulation (TUS) holds promise for noninvasive neural modulation in treating neurological disorders. Most clinically relevant targets are deep within the brain (near or at its geometric center), surrounded by other sensitive regions that need to be spared clinical intervention. However, in TUS, increasing frequency with the goal of improving spatial resolution reduces the effective penetration depth. We show that by using a pair of 1-MHz orthogonally arranged transducers, we improve the spatial resolution afforded by each of the transducers individually, by nearly 40 folds, achieving a subcubic millimeter target volume of [Formula: see text]. We show that orthogonally placed transducers generate highly localized standing waves with acoustic radiation force (ARF) arranged into periodic regions of compression and tension near the target. We further present an extended capability of the orthogonal setup, which is to impart selective pressures-either positive or negative, but not both-on the target. Finally, we share our preliminary findings that strain can arise from both particle motion (PM) and ARF with the former reaching its maximum value at the focus and the latter remaining null at the focus and reaching its maximum around the focus. As the field is investigating the mechanism of interaction in TUS by way of elucidating the mapping between ultrasound parameters and neural response, orthogonal transducers expand our toolbox by making it possible to conduct these investigations at much finer spatial resolutions, with localized and directed (compression versus tension) ARF and the capability of applying selective pressures at the target.

  View details for DOI 10.1109/TUFFC.2024.3456048

  View details for Web of Science ID 001338565700012

  View details for PubMedID 39240744

• Rank restriction for the variational calculation of two-electron reduced density matrices of many-electron atoms and molecules PHYSICAL REVIEW A Naftchi-Ardebili, K., Hau, N. W., Mazziotti, D. A. 2011; 84 (5)

  View details for DOI 10.1103/PhysRevA.84.052506

  View details for Web of Science ID 000296850500003