Millimetre-wave radar-based spirometry for the preliminary diagnosis of chronic obstructive pulmonary disease

Chronic respiratory diseases, especially chronic obstructive pulmonary disease (COPD), have high morbidity and mortality worldwide. Spirometry is regarded as the gold standard for the diagnosis of COPD. However, conventional spirometry requires expensive devices and trained personnel. Therefore, it is not feasible for conventional spirometry to popularise outside the hospital. Millimetre-wave radar has the characteristics of low cost and high integration. It can accurately capture the motion of the chest, which makes it possible to evaluate the pulmonary function of humans. A method to measure important respiratory indices in spirometry based on a 60-GHz frequency-modulated continuous-wave radar system is proposed. The impact of body motion is reduced via a dedicated body twitch correction algorithm. A new fitting formula was utilised to estimate forced expiratory volume in one second and forced vital capacity. Experimental results demonstrated that millimetre-wave radar-based spirometry can achieve a high agreement with conventional spirometry. It is potential for radar-based spirometry to be an alternative to conventional spirometry in the preliminary diagnosis of COPD outside the hospital. A method based on a 60-GHz frequency-modulated continuous-wave (FMCW) radar system is proposed to measure respiratory indices, including FEV1, FVC and FEV1/FVC. Experimental results carried out on 35 subjects demonstrated that radar-based spirometry could achieve a high agreement with conventional spirometry. It is potential for radar-based spirometry to be an alternative to conventional spirometry in the preliminary diagnosis of COPD outside the hospital.image