Ultrasound Imaging and Characterization of Biofilms Based on聽Wavelet De-noised Radiofrequency Data

详细信息    查看全文

• 作者：Kunal Vaidya ; Robert Osgood ; Dabin Ren ; Michael E. Pichichero ; Mar铆a Helguera
• 关键词：Acute otitis media ; Biofilms ; Characterization ; High-frequency ultrasound ; Haemophilus influenzae ; Streptococcus pneumoniae ; Wavelet de-noising
• 刊名：Ultrasound in Medicine and Biology
• 出版年：March, 2014
• 年：2014
• 卷：40
• 期：3
• 页码：583-595
• 全文大小：2859 K

文摘

The ability to non-invasively image and characterize bacterial biofilms in children during nasopharyngeal colonization with potential otopathogens and during acute otitis media would represent a significant advance. We sought to determine if quantitative high-frequency ultrasound techniques could be used to achieve that goal. Systematic time studies of bacterial biofilm formation were performed on three preparations of an isolated Haemophilus influenzae (NTHi) strain, a Streptococcus pneumoniae (Sp) strain and a combination of H. influenzae and S. pneumoniae (NTHi聽+ Sp) in an in聽vitro environment. The process of characterization included conditioning of the acquired radiofrequency data obtained with a 15-MHz focused, piston transducer by using a seven-level wavelet decomposition scheme to de-noise the individual A-lines acquired. All subsequent spectral parameter estimations were done on the wavelet de-noised radiofrequency data. Various spectral parameters鈥攑eak frequency shift, bandwidth reduction and integrated backscatter coefficient鈥攚ere recorded. These parameters were successfully used to map the progression of the biofilms in time and to differentiate between single- and multiple-species biofilms. Results were compared with those for confocal microscopy and theoretical evaluation of form factor. We conclude that high-frequency ultrasound may prove a useful modality to detect and characterize bacterial biofilms in humans as they form on tissues and plastic materials.