Mitigating skin tone bias in linear array in vivo photoacoustic imaging with short-lag spatial coherence beamforming

Guilherme S P Fernandes; João H Uliana; Luciano Bachmann; Antonio A O Carneiro; Muyinatu A Lediju Bell; Theo Z Pavan

doi:10.1016/j.pacs.2023.100555

Mitigating skin tone bias in linear array in vivo photoacoustic imaging with short-lag spatial coherence beamforming

Photoacoustics. 2023 Sep 11:33:100555. doi: 10.1016/j.pacs.2023.100555. eCollection 2023 Oct.

Authors

Guilherme S P Fernandes^{1

2}, João H Uliana¹, Luciano Bachmann¹, Antonio A O Carneiro¹, Muyinatu A Lediju Bell^{2

3

4}, Theo Z Pavan¹

Affiliations

¹ Department of Physics, FFCLRP, University of Sao Paulo, Brazil.
² Department of Electrical and Computer Engineering, Johns Hopkins University, USA.
³ Department of Biomedical Engineering, Johns Hopkins University, USA.
⁴ Department of Computer Science, Johns Hopkins University, USA.

Abstract

Photoacoustic (PA) imaging has the potential to deliver non-invasive diagnostic information. However, skin tone differences bias PA target visualization, as the elevated optical absorption of melanated skin decreases optical fluence within the imaging plane and increases the presence of acoustic clutter. This paper demonstrates that short-lag spatial coherence (SLSC) beamforming mitigates this bias. PA data from the forearm of 18 volunteers were acquired with 750-, 810-, and 870-nm wavelengths. Skin tones ranging from light to dark were objectively quantified using the individual typology angle (ITA $°$ ). The signal-to-noise ratio (SNR) of the radial artery (RA) and surrounding clutter were measured. Clutter was minimal (e.g., -16 dB relative to the RA) with lighter skin tones and increased to -8 dB with darker tones, which compromised RA visualization in conventional PA images. SLSC beamforming achieved a median SNR improvement of 3.8 dB, resulting in better RA visualization for all skin tones.

Keywords: 0000; 1111; Clutter artifact; Fitzpatrick scale; Individual typology angle; Melanin; Photoacoustic imaging; Short-lag spatial coherence; Skin pigmentation; Ultrasound.

Abstract

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