Model-Assisted Time-Synchronization of Cardiac MR Image and Catheter Pressure Data

Abstract

When combining cardiovascular magnetic resonance imaging (CMR) with pressure catheter measurements, the acquired image and pressure data need to be synchronized in time. The time offset between the image and pressure data depends on a number of factors, such as the type and settings of the MR sequence, duration and shape of QRS complex or the type of catheter, and cannot be typically estimated beforehand. In the present work we propose using a biophysical heart model to synchronize the left ventricular (LV) pressure and volume (P-V) data. Ten patients, who underwent CMR and LV catheterization, were included. A biophysical model of reduced geometrical complexity with physiologically substantiated timing of each phase of the cardiac cycle was first adjusted to individual patients using basic morphological and functional indicators. The pressure and volume waveforms simulated by the patient-specific models were then used as templates to detect the time offset between the acquired ventricular pressure and volume waveforms. Time-varying ventricular elastance was derived from clinical data both as originally acquired as well as when time-synchronized, and normalized with respect to end-systolic time and maximum elastance value (E N orig (t), E N t-syn (t), respectively). E N t-syn (t) was significantly closer to the experimentally obtained E N exp (t) published in the literature (p<0.05, L 2 norm). The work concludes that the model-driven time-synchronization of P-V data obtained by catheter measurement and CMR allows to generate high quality P-V loops, which can then be used for clinical interpretation.

Data-driven computational models of ventricular-arterial hemodynamics in pediatric pulmonary arterial hypertension

“…However, in most cases, the shape of the resulting PV loop lacked defined isovolumetric contraction and relaxation phases ( Figure 3A ), which can even occur when PV loop data is acquired simultaneously with an interventional cardiac MRI. Gusseva et al (2021 ; 2022) developed a biophysical heart model to align PV data. In this work, we developed an algorithm to systematically shift the pressure waveforms to determine optimally aligned PV loops.…”

Time‐Synchronization of Interventional Cardiovascular Magnetic Resonance Data Using a Biomechanical Model for Pressure‐Volume Loop Analysis

“…Pressure-volume (P-V) data is often acquired by different modalities and subject to time-synchronization errors yielding skewed shapes of PV diagrams (Figure 1 (A)). A temporal dyssynchrony could be associated with cardiac magnetic resonance imaging (MRI) acquisition and reconstruction techniques: the temporal resolution of the scanner, the type of ECG trigger / gating (prospective vs. retrospective), averaging over cardiac cycles, and detection of R-peak from a wide QRS complex (3). In addition, some delays could arise from the inertia effect of the fluid-filled catheter that varies depending on the catheter type and size (4).…”

“…A temporal dyssynchrony could be associated with cardiac magnetic resonance imaging (MRI) acquisition and reconstruction techniques: the temporal resolution of the scanner, the type of ECG trigger/gating (prospective vs. retrospective), averaging over cardiac cycles, and detection of R-peak from a wide QRS complex. 3 In addition, some delays could arise from the inertia effect of the fluid-filled catheter that varies depending on the catheter type and size. 4 A complete synchronization of the P-V signals is possible when using an intraventricular conductance catheter.…”

“…Our previous pilot study demonstrated the potential of such an approach on P-V data acquired sequentially (volumetric data during cardiac MRI followed by pressure data during cardiac catheterization) without valvular regurgitation. 3 In the present study, we aim to extend the method for simultaneously acquired P-V data (i.e. during interventional cardiac MRI) and for patients with pulmonary regurgitation (i.e.…”