J. Struijk, Dagbjört Helga Eiriksdóttir, Ásgerdur Arna Pálsdóttir, S. Schmidt
{"title":"Heart Sounds Obtained With Non-Contact Continuous-Wave Echo Doppler","authors":"J. Struijk, Dagbjört Helga Eiriksdóttir, Ásgerdur Arna Pálsdóttir, S. Schmidt","doi":"10.22489/CinC.2018.342","DOIUrl":null,"url":null,"abstract":"Heart sounds can be obtained in various ways. A recent modality is airborne ultrasound echo Doppler, which has been used either in a pulsed wave mode or a continuous wave mode. In the present work we analyse the continuous wave ultrasound echo from the chest. In 10 subjects a piezo ultrasound transceiver was used to transmit a 40 kHz acoustic sine wave directed to the chest wall. The reflected signal (echo) was recorded with a microphone and sampled at 1 MHz. The FM modulated echo was demodulated in MatLab using a quadrature signal. The signal thus obtained represented the chest displacement, which was subdivided into three frequency bands: respiration (below 0.5 Hz), movement of the myocardium (>1 Hz) and valve sounds (30–100 Hz). Above 100 Hz the signal decayed by 20 dB/decade with a noise floor above 1–2 kHz. Interestingly, signals obtained directly from the skin and signals obtained through a thin layer of clothes were similar. Non-contact continuous-wave echo Doppler thus is a promising new modality for the recording of heart sounds, although its true potential has to be further investigated.","PeriodicalId":215521,"journal":{"name":"2018 Computing in Cardiology Conference (CinC)","volume":"128 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2018 Computing in Cardiology Conference (CinC)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.22489/CinC.2018.342","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 2
Abstract
Heart sounds can be obtained in various ways. A recent modality is airborne ultrasound echo Doppler, which has been used either in a pulsed wave mode or a continuous wave mode. In the present work we analyse the continuous wave ultrasound echo from the chest. In 10 subjects a piezo ultrasound transceiver was used to transmit a 40 kHz acoustic sine wave directed to the chest wall. The reflected signal (echo) was recorded with a microphone and sampled at 1 MHz. The FM modulated echo was demodulated in MatLab using a quadrature signal. The signal thus obtained represented the chest displacement, which was subdivided into three frequency bands: respiration (below 0.5 Hz), movement of the myocardium (>1 Hz) and valve sounds (30–100 Hz). Above 100 Hz the signal decayed by 20 dB/decade with a noise floor above 1–2 kHz. Interestingly, signals obtained directly from the skin and signals obtained through a thin layer of clothes were similar. Non-contact continuous-wave echo Doppler thus is a promising new modality for the recording of heart sounds, although its true potential has to be further investigated.