Myocardial tissue motion influence on laser Doppler perfusion monitoring using tissue Doppler imaging

Abstract

Tissue motion of the beating heart generates large movement artifacts in the laser Doppler perfusion monitoring (LDPM) signal. The aim of the study was to use tissue Doppler imaging (TDI) to localise intervals during the cardiac cycle where the influence of movement artifacts on the LDPM signal is minimum. TDI velocities and LDPM signals were investigated on three calves, for normal heartbeat and during occlusion of the left anterior descending coronary artery. Intervals of low tissue velocity (TDIint, < 1 cm s(-1)) during the cardiac cycle were identified. During occlusion, these intervals were compared with low LDPM signal intervals (LDPMint, <50% compared with baseline). Low-velocity intervals were found in late systole (normal and occlusion) and late diastole (normal). Systolic intervals were longer and less sensitive to heart rate variation compared with diastolic ones. The overlap between LDPMint and TDIint in relation to TDIint length was 84+/-27% (n = 14). The LDPM signal was significantly (p < 0.001, n = 14) lower during occlusion if calculated during minimum tissue motion (inside TDIint), compared with averaging over the entire cardiac cycle without taking tissue motion into consideration. In conclusion, movement artifacts are reduced if the LDPM signal is correlated to the ECG and investigated during minimum wall motion. The optimum interval depends on the application; late systole and late diastole can be used.

Continuous Regional Myocardial Blood Flow Measurement: Validation of a Near‐Infrared Laser Doppler Device in a Porcine Model

“…In addition, the laser Doppler signal is mainly influenced by hemoglobin during end diastole. The influence of myoglobin on the Doppler shift during end diastole is negligible [13].…”

“…Our laser Doppler system utilized a nontraumatic probe position on the surface of the myocardium in combination with an LVP signal to allow triggered measurements end‐diastolically to avoid confounding artifacts caused by myocardial tissue movements [13,29].…”

“…[11] reported detachment of their intramyocardially positioned probe and bleeding after probe insertion. Suturing the laser Doppler probe epicardially to the heart prevents movement artifacts by avoiding probe movements within the created intramyocardial channel after probe insertion [11–13,16,25,29,30] or handheld application [3]. In addition, suturing the probe onto the epicardial surface eliminates relative motion of the probe to the heart [29].…”

A System for On-Line Laser Doppler Monitoring of ECG-Traced Myocardial Perfusion

“…Studies using echocardiographic tissue Doppler imaging (TDI) indicate reduced tissue velocity in the myocardial wall in relation to late systole and late diastole [3], [4]. A study performed by our group on the beating calf heart using both LDPM and TDI demonstrated intervals with low tissue velocity of the left anterior myocardial wall at late systole and late diastole [5], [6]. During these intervals a stable laser Doppler signal was recorded during normal blood flow conditions.…”

Optical Monitoring of Cerebral Microcirculation

“…Previous animal studies with optical measurements in myocardial and brain tissue have shown a potential for using LDF to study the microvascular perfusion [8][9][10]. Currently the techniques are being adapted for human studies together with research and in close collaboration with clinics for different interventions and treatments.…”