**6.2 Cardiac magnetic resonance imaging**

Multimodality imaging can provide crucial preoperative information, such as a functional and structural assessment of the right ventricle and the tricuspid valve anomaly. This data helps with surgical planning and preoperative counseling. Multimodality imaging can provide personalized details of distinct components of the tricuspid valve. While echocardiography provides correct valvar anatomical details and assessment of right ventricular pressure, cardiac magnetic resonance (CMR) enables a more accurate evaluation of the regurgitant fraction and right ventricular function, which complements the information provided by echocardiography.

Before the cone operation, CMR enables functional and anatomical examination of the RV and tricuspid valve abnormality, which is crucial for surgical planning [30]. Preoperative CMR offered extra information in more than three-quarters of patients, according to a study by Johnson et al., with 69% of the findings changing surgical therapy [31] . Leaflet attachments of the posterior/inferior and anterior leaflets to the RV wall can also be assessed using CMR. There are two types of attachments—focal attachments and linear attachments. Normal attachments, such as focal attachments, allow unobstructed communication between the atrialized and functional RV. Linear attachments occur when the leaflet is completely or partially attached to a muscle shelf at the joint (**Figure 13**).

Additionally, CMR can measure the degree of displacement and rotation of the tricuspid valve and can also measure the Great Ormond Street Hospital score

#### **Figure 14.**

*Cardiac MRI image in four-chamber view showing the calculation of the great Ormond street hospital index using the right atrium and atrialized right ventricle area divided by the sum of the functional right ventricle, left atrium, and left ventricle.*

(**Figure 14**). Most importantly, CMR gives an accurate assessment of chamber size including atrialized and functional right ventricle and RV function. CMR is the gold standard for RV size and function and overcomes the limitations of 2D echocardiography to measure RV size and function.
