Cardiovascular magnetic resonance imaging of myocardium and pulmonary arterial pressure

Abstract

Heart failure (HF) is a clinical syndrome characterized by high morbidity and mortality. HF can be associated with alteration in myocardial tissue composition such as focal myocardial fibrosis, also referred to as scarring, as well as the development of pulmonary hypertension (PH). The prevalence of HF and PH is increasing worldwide, mainly due to the aging population. This emphasizes the need for early diagnosis, identification of underlying etiology and appropriate treatment.

Cardiovascular magnetic resonance (CMR) is not only the reference standard for the assessment of cardiac morphology, function, and myocardial viability, but can also provide precise quantitative information on myocardial tissue composition and cardiovascular hemodynamics.

In study I, we found that synthetic late gadolinium enhancement (SynLGE) generated from post-contrast T1 mapping was highly accurate in identifying both ischemic and non-ischemic focal myocardial fibrosis. This method proved to be a valuable complement to conventional late gadolinium enhancement (LGE) imaging. Study II, employed T1 mapping to quantify the dynamic distribution of an intravenous iron substitution agent, ferric carboxymaltose, into different tissues including the myocardium. This understanding is of value for determining the potential benefits of iron substitution therapy in patients with HF.

In studies III and IV we investigated the application of the compressed sensing (CS) acceleration technique to multi-two-dimensional (CS-M2D) and true fourdimensional (4D) flow image acquisition by CMR. CS enabled a substantial reduction in image acquisition time while maintaining accuracy in determining mean pulmonary artery pressure (mPAP). Moreover, in study IV, we validated CSM2D and CS-4D flow and achieved excellent agreement in mPAP estimation when compared to invasively measured mPAP by right heart catheterization as the reference standard.

In conclusion, this thesis highlights the importance of quantitative CMR in understanding etiological and pathophysiological aspects in HF. These findings are valuable for the early detection of HF and PH and show promise for guiding therapeutic decision to prevent disease progression and complications in patients with HF.