The representative metabolite images with color overlay are based on Fourier interpolation to a resolution of 64×64.

<p>Both the PCr and the β-ATP metabolite images show a clear separation between myocardium and skeletal muscle of the thorax. The myocardium is characterized by lower PCr concentrations and higher ATP concentrations compared to skeletal muscle, whereby the higher myocardial ATP concentration is partly caused by blood contamination.</p

The clinical and demographical data of the volunteers separated for the different age groups are given.

<p>Significant differences are marked by bold letters.</p

The montage of localizers and spectra are derived from a 62 year old, healthy man.

<p>The axial, coronal and sagittal images were acquired for localization purposes. The grid reflects the position of the MR spectroscopic slab, originally measured with 8×8 phase encoding steps, which were interpolated to a matrix of 16×16 in the k-space. The large, semi-transparent rectangles on the localizer images show the positions of spectra, which were averaged for the determination of left-ventricular PCr/β-ATP ratio (A–H). The small rectangle on the axial localizer image represents the position of a voxel from the thorax muscles, which is given for comparison. On each spectrum, pictograms of the localizer images are superimposed on the right margin.</p

The scatter plot demonstrates the inverse linear relationship between age and left-ventricular phosphocreatine (PCr) to adenosine-triphosphate (ATP) ratio in 196 healthy volunteers.

<p>Correlation tests between left-ventricular PCr/β-ATP ratios and age were performed for the entire data set as well as the old (already published in 2003) and the new data set by using the Pearson’s correlation coefficient r. In addition, a linear regression analysis was done for the entire data set.</p

Linear correlation between PWV, clinical characteristics, oscillometric measures and CMR-derived parameters.

<p>PWV_OSC: pulse wave velocity assessed by transformation of oscillometrically defined brachial pressure wave form, PWV_CMR: pulse wave velocity assessed by cardiac magnetic resonance, RR_sys: systolic blood pressure, RR_dia: diastolic blood pressure, DC_aA: distensibility coefficient of the ascending aorta, DC_dA: distensibility coefficient of the descending thoracic aorta, DC_abA: distensibility coefficient of the abdominal aorta, DC mean: mean DC of all three aortic levels, DC central: DC at different aortic levels calculated using central aortic pulse pressure.</p><p>Linear correlation between PWV, clinical characteristics, oscillometric measures and CMR-derived parameters.</p

Assessment of aortic pulse wave velocity.

<p>Evaluation of aortic pulse wave velocity using (a1) a transfer function from (a2) brachial pressure wave analysis and (b) the cardiac magnetic resonance-derived transit time method based on phase-contrast imaging. R1 and R2 indicate the aortic region.</p

Methods´ agreement.

<p>Bland-Altman plots representing the agreement between the oscillometric method and cardiac magnetic resonance for the assessment of aortic pulse wave velocity. Corresponding coefficient of variation was 15%.</p

Study population characteristics.

<p>RR_sys: systolic blood pressure, RR_dia: diastolic blood pressure.</p><p>Study population characteristics.</p

Correlation of aortic pulse wave velocity assessed by the two methods.

<p>Linear correlation between aortic pulse wave velocities assessed by brachial oscillometry (PWV_OSC) and cardiac magnetic resonance (PWV_CMR).</p

Oscillometric measures and CMR-derived parameters of the study cohort.

<p>PWV_OSC: pulse wave velocity assessed by transformation of oscillometrically defined brachial pressure wave form, RR_sys: systolic blood pressure, RR_dia: diastolic blood pressure, DC_aA: distensibility coefficient of the ascending aorta, PWV_CMR: pulse wave velocity assessed by cardiac magnetic resonance, DC_aA: distensibility coefficient of the ascending aorta, DC_dA: distensibility coefficient of the descending thoracic aorta, DC_abA: distensibility coefficient of the abdominal aorta, DC mean: mean DC of all three aortic levels, DC central: DC at different aortic levels calculated using central aortic pulse pressure, R1: aortic arch, R2: descending thoracic to abdominal aorta, R3: R1 + R2 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116862#pone.0116862.g001" target="_blank">Fig. 1b</a>).</p><p>Oscillometric measures and CMR-derived parameters of the study cohort.</p