About 50% of the patients with heart failure suffer from predominant diastolic dysfunction.

Diastolic dysfunction is a sensitive marker of cardiac disease.

MRI offers a variety of structural and functional parameters in order to diagnose diastolic dysfunction.

Clinicians (radiologists and cardiologists) who wish to obtain a survey over the possibilities of diastolic function analysis using MRI as well as physicists and engineers who want to get a basic understanding of diastolic dysfunction and the clinical needs with respect to this topic.Normal diastolic function and the patho-physiology of diastolic dysfunction will be explained. The importance of diastolic function analysis for heart failure patients will be highlighted. Furthermore, structural and functional MRI parameters of diastolic function will be presented and their diagnostic value will be discussed.Diastolic dysfunction is characterized by an impaired active relaxation and/or passive ventricular compliance resulting in an increase in intraventricular end-diastolic pressure. Diastolic dysfunction often precedes reduced systolic function and is therefore a sensitive marker of cardiac disease. Furthermore, diastolic dysfunction accounts for up to 50% of all heart failure cases. The incidence of predominant diastolic heart failure with preserved left ventricular ejection fraction is increasing as the population gets older. Underlying diseases are hypertensive heart disease, hypertrophic cardiomyopathy, aortic valve stenosis or storage diseases of the heart. In contrast to systolic heart failure, there is no therapeutic strategy currently available which might improve the outcome of the patients ¹. One aspect contributing to this therapeutic dilemma is the fact that the making of the diagnosis of diastolic dysfunction is still challenging. Usually the diagnosis is based on parameters derived from echocardiography in combination with laboratory findings such as elevated BNP values ². But echo-derived parameters are limited by reduced reproducibility and high dependency on the examiner as well as the acoustic window of the patient. In addition, diastolic Doppler parameters are dependent on the Doppler angle and on loading conditions. On the other hand, diastolic function analysis relies on a high temporal resolution since the isovolumetric relaxation time, the time period of active relaxation, is very short. Therefore there is an unmet need for imaging methods providing robust and reproducible parameters of diastolic dysfunction with adequate temporal resolution suited for multi-center studies evaluating potential new therapies for diastolic dysfunction.Cardiac MRI offers various applications for the detection of diastolic dysfunction. MRI is regarded as the gold standard for the quantification of left and right ventricular volumes and masses. Raised left ventricular masses as well as augmented left atrial volumes quantified by MRI directly reflect structural aspects of diastolic dysfunction. An increased left atrial size may reflect raised left ventricular filling pressure and is associated with heart failure ³ and increased mortality ⁴. Furthermore, there are several functional MRI markers of disturbed diastolic performance. A phase-contrast based assessment of mitral inflow and pulmonary vein flow curves allows the diagnosis of diastolic dysfunction and correlates with Doppler echo values ⁵. Phase- contrast imaging of the myocardial wall (Tissue Phase Mapping) enables the analysis of myocardial early diastolic long-axis velocities with good agreement with tissue Doppler values ⁶. Myocardial long-axis motion correlates with the early diastolic pressure decay in the left ventricle ⁷. In analogy to echocardiography, the combination of velocity- encoded MR measurements of early mitral inflow and early diastolic long- axis peak velocities of the myocardium (E/Ea value) is associated with invasively measured pulmonary capillary wedge pressures as invasive marker of diastolic function. In addition, a correlation of the MRI values with E/Ea values based on echocardiography has been demonstrated ⁸. Another MRI technique used for diastolic function analysis is the calculation of peak filling rates from ventricular time-volume curves. Reduced or prolonged peak filling rates are associated with diastolic dysfunction ⁹. Ventricular time volume curves are calculated from the cine short- axis slices used for volumetric assessment of the heart without need for additional sequences. However, automated segmentation software for the delineation of the endocardium in all cardiac phases is required. MR myocardial Tagging, Tissue Phase Mapping or MR Feature Tracking allow for the evaluation of regional parameters of diastolic function or untwist. It has been demonstrated that reduced or prolonged diastolic long-axis velocities, diastolic strain-rate or untwist are associated with diastolic dysfunction in cardiac diseases ^{10 11 12}. As well as long- axis motion ⁷, untwist is also a left ventricular motion component associated with the intraventricular pressure decay during active relaxation ¹³. MR Tagging, Tissue Phase Mapping and MR Feature Tracking enable a comprehensive regional evaluation of all ventricular motion components and segments during diastole. Regional markers of diastolic dysfunction are promising in first studies but their diagnostic and prognostic value has to be evaluated in studies including more patients.Diastolic function analysis is important but still challenging in daily clinical practise. MRI offers an alternative to echocardiography providing structural as well as functional imaging parameters of diastolic dysfunction. In addition to the exact quantification of left atrial size and left ventricular mass, MRI enables a comprehensive and robust evaluation of diastolic function including the assessment of blood flow curves, peak filling rates or of three-directional regional motion or deformation.