New Cardiac Magnetic Resonance Reference Ranges for Right Ventricular Volumes and Systolic Function

Abstract

A ccurate quantitation of right ventricular (RV) volumes and systolic function provides important diagnostic and prognostic information in a wide range of conditions. In the case of heart failure, a preserved RV ejection fraction (RVEF) is associated with improved long-term survival. 1 The most recent task force criteria for the diagnosis of arrhythmogenic RV cardiomyopathy require the presence of abnormal measurements of RV end-diastolic volume or RVEF to fulfil the major imaging criterion for diagnosis of the condition.2 In pulmonary arterial hypertension, increased RV end-diastolic volume and decreased RV stroke volume independently predict mortality 3 and after myocardial infarction, RV function is an independent prognostic marker of clinical outcome. CMR methods have undergone considerable evolution and standardization during the past 2 decades. Today, balanced steady-state free precession (SSFP) is the standard for acquisition of cine CMR images because it provides much better endocardial border delimitation, shorter scan times, and higher signal:noise ratios than the formerly used spoiled gradient echo methods. 6 The overall better image quality of balanced SSFP acquisition and the ability to more clearly differentiate trabeculation from the endocardial border leads to different estimates of left ventricular and RV chamber size, with typically larger volumes and lower mass. 7 Many older studies reporting normal values are, therefore, largely obsolete, and it is important that normal values for contemporary CMR methods are available. The largest study of those using older acquisition methods was the Multi-Ethnic Study of Atherosclerosis (MESA), which included a cohort of 4204 participants for whom CMR measurements of RV volumes were available. The authors reported increased RVEF with advancing age, increased RV end-diastolic volume but lower RVEF in men versus women, lower RVEF in black versus white individuals as well as higher right ventricular enddiastolic volume and lower RVEF in obese individuals. 8,9 Several other studies 7,10 have provided normal reference ranges for RV volumes and systolic function using contemporaneous SSFP acquisition, but these are on a much smaller scale than the study by Foppa et al 11 in this issue of Circulation: Cardiovascular Imaging.Foppa et al 11 report sex-specific normative values for RV measurement from a cross-sectional study of members of the Framingham Heart Study Offspring cohort. The reported normal values are derived from the 1336 participants remaining after exclusion of those with a history of either respiratory disease, previous venous thromboembolic disease, or significant left ventricular systolic impairment, ensuring a wellcharacterized sample. In addition to providing a normal range, the study makes several important observations. RVEF was greater in women, RV volumes were higher in males, and RV volumes increased with body size while there were smaller RV volumes in older subjects. Indexation of values according to body surface area adjusted appropriatel...

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“…In some of the presented cases, the functional analysis had resulted in reduced ejection fractions, which may be attributed to suboptimal slice planning and a low number of obtained cardiac phases. It is important to highlight, as has been discussed elsewhere, that the functional parameters such as the volumes especially of the RV are dependent on chosen sequences and sequence settings, as well as on the imaging planes used for the analysis, and an uncritical comparison with clinical CMR data should be avoided [44]. The long axis view was more affected by flow artifacts when compared to the short axis view.…”