Monitoring and Synchronization of Cardiac and Respiratory Traces in Magnetic Resonance Imaging: A Review

Fiber-Optic Cardiorespiratory Monitoring and Triggering in Magnetic Resonance Imaging

“…Such time-triggered images are characterized by higher contrast of the tissues of interest, contrast of contours, signal-to-noise ratio (SNR) and both temporal and spatial resolution. Further, this form of triggering provides a scan of the heart in its specific phase of cycle that could be an important diagnostic parameter [19], [23], [24].…”

“…One can observe that the main benefits of measuring using the FOS's lie in its high sensitivity, indifference to magnetic field environment and its ability to sense both the respiratory and cardiac signals. Contrary, most standardly used triggering systems are known to be more or less sensitive to the increasing MR field strength, which makes its use limited in the ultra-high fields [19]. These limitations are summarized in Table I.…”

“…Moreover, the complexity and cost of self-gating software could put this method out of the reach for some MRI facilities [50], [51], [52], [53]. Despite having relatively higher accuracy, among the alternative approaches that were described above which require use of physical sensors have two main drawbacks: 1) Lack of standardization for placement of the required sensors which results in different signal morphology and consequently different outcome when placed on different sites of the body; and 2) Significant signal delays compared to ECG (see Figure 3), which are inherent in the sensing principle of the method and in the signal transmission or filtration [19]. Therefore, it is advantageous to develop measuring systems without the need for attachment of sensors to the patient's body.…”

“…This review paper focuses on the recent advances in monitoring of patient's cardiorespiratory activity during MRI with the option of MRI synchronization. This problematic has been already outlined in our previous paper [19] that provides a comprehensive summary of methods suitable for MRI gating and their comparison. In contrast, the focus of this paper is more in-depth and only includes the overview of the sensors based on fiber optics that were successfully tested and validated in the MR environment.…”

A Simple Low-Cost Electrocardiogram Synchronizer

“…Electrocardiogram (ECG) synchronization is sometimes required to avoid the effects of cardiac motion in medical measurements performed on the chest and abdomen [1]. This technique is widely used in standard medical imaging techniques, including magnetic resonance imaging (MRI) [2,3], intracoronary optical coherent tomography (OCT) [4], and triggered angiography non-contrast enhanced (TRANCE) [5], to prevent motion artifacts, such as shadows and blurred contours, on images.…”