Mr. Pietro Levoni Profile

Pietro Levoni

PhD Candidate at Politecnico di Milano

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Publications (3)

SPIE Journal Paper | 17 July 2023 Open Access

Robustness of tissue oxygenation estimates by continuous wave space-resolved near infrared spectroscopy

Caterina Amendola, Davide Contini, Rebecca Re, Lorenzo Spinelli, Lorenzo Frabasile, Pietro Levoni, Alessandro Torricelli

JBO, Vol. 28, Issue 07, 075002, (July 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.7.075002

KEYWORDS: Tissues, Hemodynamics, Scattering, Near infrared spectroscopy, Oxygenation, Error analysis, Simulations, Muscles, Adaptive optics, Oxygen

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SignificanceContinuous wave near infrared spectroscopy (CW-NIRS) is widely exploited in clinics to estimate skeletal muscles and brain cortex oxygenation. Spatially resolved spectroscopy (SRS) is generally implemented in commercial devices. However, SRS suffers from two main limitations: the a priori assumption on the spectral dependence of the reduced scattering coefficient [μs′(λ)] and the modeling of tissue as homogeneous.AimWe studied the accuracy and robustness of SRS NIRS. We investigated the errors in retrieving hemodynamic parameters, in particular tissue oxygen saturation (StO2), when μs′(λ) was varied from expected values, and when layered tissue was considered.ApproachWe simulated hemodynamic variations mimicking real-life scenarios for skeletal muscles. Simulations were performed by exploiting the analytical solutions of the photon diffusion equation in different geometries: (1) semi-infinite homogeneous medium and constant μs′(λ); (2) semi-infinite homogeneous medium and linear changes in μs′(λ); (3) two-layered media with a superficial thickness s1 = 5, 7.5, 10 mm and constant μs′(λ). All simulated data were obtained at source-detector distances ρ = 35, 40, 45 mm, and analyzed with the SRS approach to derive hemodynamic parameters (concentration of oxygenated and deoxygenated hemoglobin, total hemoglobin concentration, and tissue oxygen saturation, StO2) and their relative error.ResultsVariations in μs′(λ) affect the estimated StO2 (up to ±10 % ), especially if changes are different at the two wavelengths. However, the main limitation of the SRS method is the presence of a superficial layer: errors strongly larger than 20% were retrieved for the estimated StO2 when the superficial thickness exceeds 5 mm.ConclusionsThese results highlight the need for more sophisticated strategies (e.g., the use of multiple short and long distances) to reduce the influence of superficial tissues in retrieving hemodynamic parameters and warn the SRS users to be aware of the intrinsic limitation of this approach, particularly when exploited in the clinical environment.

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SPIE Journal Paper | 15 June 2022 Open Access

Multi-laboratory performance assessment of diffuse optics instruments: the BitMap exercise

Pranav Lanka, Lin Yang, David Orive-Miguel, Joshua Deepak Veesa, Susanna Tagliabue, Aleh Sudakou, Saeed Samaei, Mario Forcione, Zuzana Kovacsova, Anurag Behera, Thomas Gladytz, Dirk Grosenick, Lionel Hervé, Turgut Durduran, Karolina Bejm, Magdalena Morawiec, Michał Kacprzak, Piotr Sawosz, Anna Gerega, Adam Liebert, Antonio Belli, Ilias Tachtsidis, Frédéric Lange, Gemma Bale, Luca Baratelli, Sylvain Gioux, Alexander Kalyanov, Martin Wolf, Sanathana Konugolu-Venkata-Sekar, Marta Zanoletti, Ileana Pirovano, Michele Lacerenza, Lina Qiu, Edoardo Ferocino, Giulia Maffeis, Caterina Amendola, Lorenzo Colombo, Lorenzo Frabasile, Pietro Levoni, Mauro Buttafava, Marco Renna, Laura Di Sieno, Rebecca Re, Andrea Farina, Lorenzo Spinelli, Alberto Dalla Mora, Davide Contini, Paola Taroni, Alberto Tosi, Alessandro Torricelli, Hamid Dehghani, Heidrun Wabnitz, Antonio Pifferi

JBO, Vol. 27, Issue 07, 074716, (June 2022) https://doi.org/10.1117/12.10.1117/1.JBO.27.7.074716

KEYWORDS: Raster graphics, Optical properties, Diffuse optical imaging, Scattering, Imaging spectroscopy, Absorption, Tissue optics, Spectroscopes, Sensors, Oximetry

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SPIE Journal Paper | 2 February 2022 Open Access

Reproducibility of identical solid phantoms

Fangzhou Zhao, Pietro Levoni, Lorenzo Frabasile, Hong Qi, Michele Lacerenza, Pranav Lanka, Alessandro Torricelli, Antonio Pifferi, Rinaldo Cubeddu, Lorenzo Spinelli

JBO, Vol. 27, Issue 07, 074713, (February 2022) https://doi.org/10.1117/12.10.1117/1.JBO.27.7.074713

KEYWORDS: Scattering, Silicon, Absorption, Solids, Optical properties, Picosecond phenomena, Near infrared spectroscopy, Epoxies, Diffuse optical imaging, Visible radiation

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