Medical image processing: Quantitative evidence of digital gray scale inversion in chest radiographic examinations
DOI:
https://doi.org/10.33448/rsd-v14i11.50128Keywords:
Computer-Assisted Image Processing, Chest Radiography, Image Enhancement, Signal-to-Noise Ratio.Abstract
This study aimed to evaluate the impact of grayscale inversion, also known as the negative filter, on the physical quality of chest radiographs. This technique emerges as a promising alternative for enhancing anatomical details in low-contrast regions, thereby contributing to the optimization of diagnostic interpretation. The investigation was conducted through a comparative analysis of quantitative image quality (IQ) descriptors: Signal-to-Noise Ratio (SNR), Contrast-to-Noise Ratio (CNR), and Radiographic Contrast (RC). The results showed an increase of 15.7% in SNR and 9.9% in CNR, indicating, respectively, greater definition of anatomical structures and improved ability to differentiate tissues with similar densities—an essential characteristic for highlighting subtle details in pulmonary parenchyma. Conversely, a 5.71% reduction in RC was observed, a predictable effect resulting from tonal inversion, which smooths the overall contrast inherent to the positive scale. Therefore, it is concluded that the application of the negative filter preserves diagnostic image quality while enhancing the perception of subtle anatomical structures in chest radiographs.
References
Alvarez, M., et al. (2022). Dose efetiva e nível de referência de dose (DRL) em radiologia em um hospital terciário. Revista Brasileira de Física Médica, 16, 678–678.
Baroni, R. H., et al. (2025). Volume 13 – Tórax. Editora dos Editores.
Bontrager, K. L., & Lampignano, J. P. (2015). Tratado de posicionamento radiográfico e anatomia associada. Elsevier Brasil.
Bushberg, J. T., & Boone, J. M. (2011). The essential physics of medical imaging. Lippincott Williams & Wilkins.
Bushong, S. C. (2022). Manual de radiología para técnicos: Física, biología y protección radiológica. Elsevier Health Sciences.
Carestream. (n.d.). Documento técnico | Software CARESTREAM Bone Suppression: Supressão do osso para imagens radiográficas do tórax. Carestream Health. Recuperado em 17 de outubro de 2025, de https://www.carestream.com
Claus, T. V., et al. (2024). A influência da lei do inverso do quadrado da distância nos indicadores de exposição e qualidade de imagem para exames radiográficos de pelve. Research, Society and Development, 13(4), e1013445448.
Dance, D. R., et al. (2014). Diagnostic radiology physics. International Atomic Energy Agency, 299, 12–14.
Ledda, R. E., et al. (2022). The diagnostic value of grey-scale inversion technique in chest radiography. La Radiologia Medica, 127(3), 294–304.
Mendes, H. R., Silva, J. C., & Tomal, A. (2019). Simulação Monte Carlo em radiografia de tórax: Estudos de dose e qualidade da imagem. Revista Brasileira de Física Médica, 13(1), 145–153.
Mraity, H. A. A. B., et al. (2016). Development and validation of a visual grading scale for assessing image quality of AP pelvis radiographic images. The British Journal of Radiology, 89(1061), 20150430.
Pereira, A. S. et al. (2018). Metodologia da pesquisa científica. [free ebook]. Santa Maria. Editora da UFSM.
Robinson, J. W., et al. (2013). Grey-scale inversion improves detection of lung nodules. The British Journal of Radiology, 86(1021), 27961545.
Tompe, A., & Sargar, K. (2020). X-ray image quality assurance.
Queiroz, J. E. R., & Gomes, H. M. (2006). Introdução ao processamento digital de imagens. Rita, 13(2), 11–42.
Vianna, E. R. L., & Schwarz, A. P. (2020). Desenvolvimento e construção de um fantoma de tórax para uso nos estudos de imagens radiológicas [Trabalho de Conclusão de Curso, Universidade Franciscana – UFN].
Wayne, R. (2021). Software para processamento e análise de imagens. National Institute of Mental Health, Java. Recuperado em 5 de setembro de 2025, de http://rsbweb.nih.gov/ij/download.html
Weis, G. L., Müller, F. M., & Schuch, L. A. (2013). Redução da dose de radiação em pacientes e equipes médicas pelo uso de filtros adicionais de cobre e alumínio nas saídas de tubos de raios X em equipamentos de hemodinâmica. Revista Brasileira de Física Médica, 7(3), 138-144.
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Copyright (c) 2025 Thiago Victorino Claus, Stéfani König Alves da Silva, Bruna Gai Ruviaro, Maria Luísa Silva Mendes, Marina Luiz Alves, Karoline Adriana Catelãn Pereira, Silvio Atilio Michelin Bertagnolli
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