Measuring multi-site pulse transit time with an AI-enabled mmWave radar

Clinical Snapshot

Key Findings

• P Value: Not reported

• Effect Size: Correlation coefficients 0.75-0.86 for PTT measurement

• Primary Outcome: Pulse transit time correlation with reference sensors across three physiological pathways

• Nnt Or Sensitivity: DBP estimation correlation 0.90-0.91, mean error -0.62 to 0.06 mmHg, SD 4.54-5.20 mmHg

• Confidence Interval: Not reported

Clinical Application

Requires specialized mmWave radar equipment and trained operators; feasibility depends on cost-effectiveness and integration with existing monitoring systems Could complement existing cardiovascular monitoring under Medicare if proven cost-effective; would require TGA approval for therapeutic goods registration; aligns with RACGP guidelines for cardiovascular risk assessment Adults requiring cardiovascular monitoring, particularly those needing continuous or frequent blood pressure assessment

Abstract

Pulse Transit Time (PTT) is a measure of arterial stiffness and a physiological marker associated with cardiovascular function, with an inverse relationship to diastolic blood pressure (DBP). We present an AI-enabled mmWave system for contactless multi-site PTT measurement using a single radar. By leveraging radar beamforming and deep learning algorithms our system simultaneously measures PTT and estimates diastolic blood pressure at multiple sites. The system was evaluated across three physiological pathways - heart-to-radial artery, heart-to-carotid artery, and mastoid area-to-radial artery - achieving correlation coefficients of 0.75-0.86 compared to contact-based reference sensors for measuring PTT. Furthermore, the system demonstrated correlation coefficients of 0.90-0.91 for estimating DBP, and achieved a mean error of -0.62-0.06 mmHg and standard deviation of 4.54-5.20 mmHg, meeting the FDA's AAMI guidelines for non-invasive blood pressure monitors. These results suggest that our proposed system has the potential to provide a non-invasive measure of cardiovascular health across multiple regions of the body.