Autor(es)

Ceccato, Roberto C. ; Pigatto, Andre V. ; Aster, Richard C. ; Pai, Chi-Nan ; Mueller, Jennifer L. ; Furuie, Sergio S.

• Tipo de documento: Artigo Científico
• Fonte: IEEE Transactions on Biomedical Engineering; v. 72, n. 9, p. 12-pg., 2025-09-01.

Resumo

Objective: Quantitative time of flight in transmission mode ultrasound computed tomography (TFTM USCT) is a promising, cost-effective, and non-invasive modality, particularly suited for functional imaging. However, TFTM USCT encounters resolution challenges due to path information concentration in specific medium regions and uncertainty in transducer positioning. This study proposes a method to enhance resolution and robustness, focusing on low-frequency TFTM USCT for pulmonary imaging. Methods: The proposed technique improves the orientation of steepest descent algorithm steps, preventing resolution degradation due to path information concentration, while allowing for a posteriori sensor positioning retrieval. Total variation regularization is employed to stabilize the inverse problem, and a modified Barzilai-Borwein method determined the step size in the steepest descent algorithm. The proposed method was validated through simulations of data on healthy and abnormal cross-sections of a human chest using MATLAB's k-Wave toolbox. Additionally, experimental data were collected using a Verasonics Vantage 64 low-frequency system and a ballistic gel torso-mimicking phantom to assess robustness under a more realistic environment, closer to that of a clinical situation. Results: The results showed that the proposed method significantly improved image quality and successfully retrieved sensor locations from imprecise positioning. Significance: This study is the first to address transducer location uncertainty on a transducer belt in TFTM USCT and to apply an estimated gradient approach. Additionally, low-frequency USCT for lung imaging is quite novel, and this work addresses practical questions that will be important for translational development. (AU)

• Processo FAPESP: 23/15074-1 - Avaliação de Alternativas para a Solução do Problema Inverso na Tomografia Quantitativa por Tempo de Voo usando Ultrassom no Modo Pulso-Eco
• Beneficiário: Roberto Costa Ceccato
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto
• Processo FAPESP: 21/13997-0 - Reconstrução tomográfica utilizando ultrassom a partir do hardware de sonotrombólise
• Beneficiário: Roberto Costa Ceccato
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto