Doppler ultrasound compared with electrocardiogram and pulse oximetry cardiac triggering: A pilot study

Abstract

Cine cardiac MRI using DUS was successfully demonstrated. DUS triggering is an alternative method for cardiac MRI and may be applied in a clinical setting.

Doppler ultrasound triggering for cardiac MRI at 7T

“…Image quality was quantitatively analyzed by assessing endocardial blurring. The wave‐like pattern is in accordance with previously reported findings at 1.5 T and 3 T and can be explained by peak radial and longitudinal velocities of the midventricular and basal myocardium at this phase of the cardiac cycle . The difference in EB between systolic and diastolic heart phases is a consequence of reduced EB during cardiac quiescence as a result of reduced radial, tangential, and longitudinal myocardial velocities.…”

“…To evaluate DUS for cardiac triggering, DUS was compared with POX during MRI, where all trigger signals were recorded simultaneously. The quality between DUS and POX trigger signals was not significantly different and allowed freezing cardiac motion with good image quality with a similar confidence interval than previously reported (19). Image quality was quantitatively analyzed by assessing endocardial blurring.…”

“…The DUS trigger setup is schematically shown in Figure 1 and was similar to the previously used setup for DUS gating at 1.5 and 3 T (19,20). The custom-built DUS electronic was placed outside of the scanner room, transmitting 1-MHz ultrasound pulses with a repetition frequency of 3.2 kHz and an acoustic intensity of 4.6 mW/cm 2 to a single piezoelectric element.…”

“…Therefore, it is not objected to the MHD effects and does not interact with the MR image acquisition. Doppler ultrasound triggering has already been evaluated successfully in healthy volunteer studies at 1.5 and 3 T and showed no significant differences to ECG or POX gating, and no disturbances. However, the main benefit of DUS gating is expected at 7T, where the ECG is subject to the MHD effect, but the applicability at ultrahigh field has not been investigated yet.…”

Is Abdominal Fetal Electrocardiography an Alternative to Doppler Ultrasound for FHR Variability Evaluation?

“…Their straight application to the FHR signals being provided by fetal monitors raised a question how a limited accuracy of the ultrasound approach affects determination of the cardiac intervals, and thus the variability indices values. Several research studies were aimed at evaluation of the reliability of the ultrasound method in reference to the direct electrocardiography (Ibrahimy et al, 2003; Reinhard et al, 2010, 2012; Cohen et al, 2012; Kimura et al, 2012; Desai et al, 2013; Kording et al, 2015). However, they were aimed at comparing the signal loss episodes or directly the FHR values.…”