Uloga magnetske rezonancije srca u dijagnostičkoj obradi bolesnika s kardiomiopatijama

Dora Grgat, Maja Hrabak Paar

Magnetska rezonancija srca je neinvazivna dijagnostička metoda kojom se dobiva detaljan uvid u morfologiju i funkciju srca. Visoko je reproducibilna i iznimno precizna. Kardiovaskularne bolesti vodeći su uzrok smrti u svijetu. Kardiomiopatije definiramo kao poremećaj miokarda u kojem je miokard strukturalno i funkcionalno abnormalan u odsutnosti koronaropatije, hipertenzije, bolesti zalistaka i kongenitalnih bolesti srca koje bi uzrokovale toliki poremećaj. Uzevši u obzir da su kardiomiopatije često asimptomatske te da prvi simptom može biti iznenadna srčana smrt, jasna je potreba za točnom i pravovremenom dijagnozom. Pravovremeno liječenje može znatno produljiti životni vijek i kvalitetu života bolesnika. Danas je magnetska rezonancija srca postala nezaobilaznim dijelom dijagnostike i praćenja liječenja bolesnika s kardiomiopatijama. Osim dijagnostike i praćenja, magnetska rezonancija srca može ukazati na etiologiju i prognozu same bolesti. Danas su u upotrebi različite tehnike snimanja, a temelje se na principima nuklearne magnetske rezonancije. Steady state-free precession dinamički prikaz omogućava dinamično oslikavanje kretanja stijenki miokarda s jasnom granicom između krvi i endokarda. Kontrastnim sredstvima baziranima na gadoliniju prikazuju se područja fibroze i nekroze, a temeljem distribucije takvih lezija možemo donositi zaključke o etiologiji kardiomiopatije. Mjerena slika T2 sa supresijom signala masti koristi se za prikaz edema miokarda. Mapiranjem T1 i T2 kvantificira se vrijeme relaksacije T1, odnosno T2 u svakom pikselu. Mapiranje T2* omogućuje kvantifikaciju količine nakupljenog željeza u miokardu. U ovom radu prikazane su suvremene tehnike magnetske rezonancije srca i njihova uloga u dijagnostici kardiomiopatija.

Cardiac magnetic resonance imaging is a noninvasive imaging modality that gives us a better look at cardiac function and morphology. It is highly accurate and reproducible.Cardiovascular diseases are the leading cause of mortality worldwide. Cardiomyopathy is a myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease, and congenital heart disease sufficient to cause the observed myocardial abnormality. Considering that most cardiomyopathies are often asymptomatic and their first manifestation is sometimes sudden cardiac death, the need for accurate and timely diagnosis is obvious. Early management can extend the patients’ life expectancy and provide a better quality of life. Today cardiac magnetic resonance is an integral part of diagnosing and monitoring patients with cardiomyopathies. Besides diagnosing and monitoring patients, cardiac magnetic resonance can provide aetiological assessment and prognosis.Multiple imaging techniques are used and are all based on principles of nuclear magnetic resonance. Steady-state free precession cine imaging allows dynamic imaging of cardiac wall motion with superior blood-endocardial border definition. Gadolinium based contrast agents highlight areas of myocardial fibrosis and necrosis, and based on distribution of enhancing areas it is possible to determine the aetiology of cardiomiopathy. T2-weighted fat-suppressed short-tau inversion recovery imaging shows increased signal in the presence of myocardial oedema. T1 and T2 mapping provide a pixel-by-pixel method of quantifying T1 and T2 relaxation time, respectively. T2* mapping allows quantification of myocardial tissue iron levels.This review paper explains modern cardiac magnetic resonance imaging modalities and their role in the diagnostic work-up of patients with cardiomyopathy.