Anne-Marie Koop

214 CMR 53,54 .Resultsregardingmyocardialdeformationmeasurementsarestillpreliminary in this specific group of patients 55–57 . Of course, in clinical practice, echocardiography is a very accessible tool to identify abnormal loading conditions by recognition of shunts and valve insufficiencies in case of volume load, and stenosis and pulmonary hypertension by increased gradients and septal flattening in case of pressure load. Pressure-volume analysis by means of invasive heart catheterization is an available alternative for invasive hemodynamic and functional assessments. This technique is widely regarded indicative for load-independent ventricular function, but also comes with limitations that currently hamper the theoretical benchmark status of PV-loops in RV in small animals. For example, deriving reproducible and accurate volume and flow measurements is challenging in these small animals and many procedures require open-chest measurements. Furthermore, serial assessments are difficult if not unfeasible due to the invasive nature of the technique. Compared to both echocardiography and catheterization, assessment of volumes and function will be more accurate with CMR. In research, it is important for translatability to obtain results using modalities that can also be used for clinical practice. Therefore, development of standardized methods and optimization in experimental protocols is highly relevant. The current protocol describes the use of self-gated CMR, which obviates the need for ECG triggering and respiratory gating. This method has been described previously in a report from the same institution, demonstrating good intra- and interobserver variability 58 for example, a myocardial infarction. Cardiac MRI is often used because it is noninvasive and provides high temporal and spatial resolution for the left and right ventricle. In animal cardiac MRI, the quality of the required electrocardiogram signal is variable and sometimes deteriorates over time, especially with infarcted hearts or cardiac hypertrophy. Therefore, we compared the self-gated IntraGateFLASH method with a prospectively triggered FLASH (fast low-angle shot. Another method that could be used if the self-gated method is unavailable, is prospective ECG triggering. However, a previous report from this institution demonstrated that the self-gated method provides less variability, better signal and contrast-to-noise ratios, and less arrhythmia-induced artifacts. Therefore, we recommend using the self-gated method, as stated in the current protocol. Accurate assessment of RV pressure load is crucial in order to validate the PAB model. This can be performed by means of invasive heart catheterization, for example. However, disadvantages of such invasive procedures are that they are very hazardous and complex to perform serially or during the follow- up time of the study and are therefore generally performed just before termination. However, at termination, RV pressure is not only dependent on the tightness of the banding but becomes increasingly dependent on RV function. Whenever RV