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Elevated mean pulmonary arterial pressure (mPAP), or pulmonary hypertension (PH), is associated with vortical blood flow along the main pulmonary artery. We present and validate a method for automated detection and tracking of the PH-related vortex from magnetic resonance 4D flow data that allows estimation of mPAP.The proposed method detects the presence of a PH-related vortex in the main pulmonary artery based on geometrical properties of swirling streamlines and estimates mPAP from the PH-related vortex duration (tVisually and automatically determined tAn automated method for PH-related vortex detection and tracking from magnetic resonance 4D flow data was introduced, which demonstrated very good agreement with visual analysis and accurate estimation of elevated mPAP.

Objectives The aims of this study were to develop a comprehensive cardiovascular magnetic resonance (CMR) approach to diastolic dysfunction (DD) grading and to evaluate the accuracy of CMR in the diagnosis of DD compared with echocardiography. Background Left ventricular DD is routinely assessed using echocardiography. Methods Consecutive clinically referred patients (n = 46; median age 59 years; interquartile range: 46 to 68 years; 33% women) underwent both conventional echocardiography and CMR. CMR diastolic transmitral velocities (E and A) and myocardial tissue velocity (e′) were measured during breath-hold using a validated high–temporal resolution radial sector-wise golden-angle velocity-encoded sequence. CMR pulmonary artery pressure was estimated from 4-dimensional flow analysis of blood flow vortex duration in the pulmonary artery. CMR left atrial volume was measured using the biplane long-axis area-length method. Both CMR and echocardiographic data were used to perform blinded grading of DD according to the 2016 joint American and European recommendations. Results Grading of DD by CMR agreed with that by echocardiography in 43 of 46 cases (93%), of which 9% were normal, 2% indeterminate, 63% grade 1 DD, 4% grade 2 DD, and 15% grade 3 DD. There was a very good categorical agreement, with a weighted Cohen kappa coefficient of 0.857 (95% confidence interval: 0.73 to 1.00; p Conclusions A comprehensive CMR protocol for grading DD encompassing diastolic blood and myocardial velocities, estimated pulmonary artery pressure, and left atrial volume showed very good agreement with echocardiography.

BACKGROUND Quantification of myocardial blood flow (MBF) from dynamic contrast-enhanced (DCE) MRI can be performed using a signal intensity model that incorporates T1 values of blood and myocardium. PURPOSE To assess the impact of T1 values on pixelwise MBF quantification, specifically to evaluate the influence of 1) study population-averaged vs. subject-specific, 2) diastolic vs. systolic, and 3) regional vs. global myocardial T1 values. STUDY TYPE Prospective. SUBJECTS Fifteen patients with chronic coronary heart disease. FIELD STRENGTH/SEQUENCE 3T; modified Look-Locker inversion recovery for T1 mapping and saturation recovery gradient echo for DCE imaging, both acquired in a mid-ventricular short-axis slice in systole and diastole. ASSESSMENT MBF was estimated using Fermi modeling and signal intensity nonlinearity correction with different T1 values: study population-averaged blood and myocardial, subject-specific systolic and diastolic, and segmental T1 values. Myocardial segments with perfusion deficits were identified visually from DCE series. STATISTICAL TESTS The relationships between MBF parameters derived by different methods were analyzed by Bland-Altman analysis; corresponding mean values were compared by t-test. RESULTS Using subject-specific diastolic T1 values, global diastolic MBF was 0.61 ± 0.13 mL/(min·g). It did not differ from global MBF derived from the study population-averaged T1 (P = 0.88), but the standard deviation of differences was large (0.07 mL/(min·g), 11% of mean MBF). Global diastolic and systolic MBF did not differ (P = 0.12), whereas global diastolic MBF using systolic (0.62 ± 0.13 mL/(min·g)) and diastolic T1 values differed (P

Objectives Longitudinal hemodynamic follow-up is important in the management of pulmonary hypertension (PH). This study aimed to evaluate the potential of MR 4-dimensional (4D) flow imaging to predict changes in the mean pulmonary arterial pressure (mPAP) during serial investigations. Methods Forty-four adult patients with PH or at risk of developing PH repeatedly underwent routine right heart catheterization (RHC) and near-term MR 4D flow imaging of the main pulmonary artery. The duration of vortical blood flow along the main pulmonary artery was evaluated from MR 4D velocity fields using prototype software and converted to an MR 4D flow imaging-based mPAP estimate (mPAPMR) by a previously established model. The relationship of differences between RHC-derived baseline and follow-up mPAP values (ΔmPAP) to corresponding differences in mPAPMR (ΔmPAPMR) was analyzed by means of regression and Bland-Altman analysis; the diagnostic performance of ΔmPAPMR in predicting mPAP increases or decreases was investigated by ROC analysis. Results Areas under the curve for the prediction of mPAP increases and decreases were 0.92 and 0.93, respectively. With the natural cutoff ΔmPAPMR = 0 mmHg, mPAP increases (decreases) were predicted with an accuracy, sensitivity, and specificity of 91% (91%), 85% (89%), and 94% (92%), respectively. For patients in whom 4D flow allowed a point estimate of mPAP (mPAP > 16 mmHg), ΔmPAPMR correlated strongly with ΔmPAP (r = 0.91) and estimated ΔmPAP bias-free with a standard deviation of 5.1 mmHg. Conclusions MR 4D flow imaging allows accurate non-invasive prediction and quantification of mPAP changes in adult patients with PH or at risk of developing PH. Trial registration ClinicalTrials.gov identifier: NCT00575692 and NCT01725763 Key Points • MR 4D flow imaging allows accurate non-invasive prediction of mean pulmonary arterial pressure increases and decreases in adult patients with or at risk of developing pulmonary hypertension. • In adult patients with mean pulmonary arterial pressure > 16 mmHg, MR 4D flow imaging allows estimation of longitudinal mean pulmonary arterial pressure changes without bias with a standard deviation of 5.1 mmHg.

This work discusses nuclear magnetic relaxation effects in glycerol subject to a strong electric field. The methods used are 1.5 T magnetic resonance imaging (MRI), referenced by 9.4 T nuclear magnetic resonance (NMR). While MRI allows a glycerol probe to be sampled with a high voltage (HV) of 16 kV applied to the probe, NMR provides precise molecular data from the sample, but the sample cannot be tested under HV. Using MRI, the recording of magnetic relaxation times was possible while HV was applied to the glycerol. NMR spectroscopy was used to confirm that MRI provides a reasonably accurate estimation of temperature. The applied HV was observed to have a negligible effect on the spin–lattice relaxation time T1, which represents the energy release to the thermal bath or system enthalpy. In contrast to that, the spin–spin relaxation time T2, which does represent the local entropy of the system, shows a lower response to temperature while the liquid is electrically stressed. These observations point toward a proton population in electrically stressed glycerol that is more mobile than that found in the bulk, an observation that is in agreement with previously published results for water.

Background Pulmonary hypertension is definitively diagnosed by the measurement of mean pulmonary artery (PA) pressure (mPAP) using right heart catheterization. Cardiovascular magnetic resonance (CMR) four-dimensional (4D) flow analysis can estimate mPAP from blood flow vortex duration in the PA, with excellent results. Moreover, the peak systolic tricuspid regurgitation (TR) pressure gradient (TRPG) measured by Doppler echocardiography is commonly used in clinical routine to estimate systolic PA pressure. This study aimed to compare CMR and echocardiography with regards to quantitative and categorical agreement, and diagnostic yield for detecting increased PA pressure. Methods Consecutive clinically referred patients (n = 60, median [interquartile range] age 60 [48–68] years, 33% female) underwent echocardiography and CMR at 1.5 T (n = 43) or 3 T (n = 17). PA vortex duration was used to estimate mPAP using a commercially available time-resolved multiple 2D slice phase contrast three-directional velocity encoded sequence covering the main PA. Transthoracic Doppler echocardiography was performed to measure TR and derive TRPG. Diagnostic yield was defined as the fraction of cases in which CMR or echocardiography detected an increased PA pressure, defined as vortex duration ≥15% of the cardiac cycle (mPAP ≥25 mmHg) or TR velocity > 2.8 m/s (TRPG > 31 mmHg). Results Both CMR and echocardiography showed normal PA pressure in 39/60 (65%) patients and increased PA pressure in 9/60 (15%) patients, overall agreement in 48/60 (80%) patients, kappa 0.49 (95% confidence interval 0.27–0.71). CMR had a higher diagnostic yield for detecting increased PA pressure compared to echocardiography (21/60 (35%) vs 9/60 (15%), p 2 = 0.65, p Conclusions There is good quantitative and fair categorical agreement between estimated mPAP from CMR and TRPG from echocardiography. CMR has higher diagnostic yield for detecting increased PA pressure compared to echocardiography, potentially due to a lower sensitivity of echocardiography in detecting increased PA pressure compared to CMR, related to limitations in the ability to adequately visualize and measure the TR jet by echocardiography. Future comparison between echocardiography, CMR and invasive measurements are justified to definitively confirm these findings.

Cardiac magnetic resonance imaging (MRI) represents the established reference standard method for the assessment of cardiac function and non-invasive evaluation of myocardial tissue in a variety of clinical questions, wherein quantification of cardiac parameters gains growing diagnostic and differential-diagnostic importance. This review aims to summarize established and newly emerging quantitative parameters, which are assessed in routine cardiac MRI. Interrelations and interdependencies between metrics are explained, and common factors affecting quantitative results are discussed. The review is based on a PubMed literature research using the search terms "cardiac magnetic resonance" and "quantification", "recommendations", "quantitative evaluation/assessment", "reference method", "reference/normal values", "pitfalls" or "artifacts" published between 2000-2019. Quantitative functional, phase contrast, and perfusion imaging, as well as relaxation time mapping techniques give opportunity for assessment of a large number of quantitative cardiac MRI parameters in clinical routine. Application of these techniques allows for characterization of function, morphology and perfusion of the heart beyond visual analysis of images, either in primary evaluation and comparison to normal values or in patients' follow-up and treatment monitoring. However, with implementation of quantitative parameters in clinical routine, standardization is of particular importance as different acquisition and evaluation strategies and algorithms may substantially influence results, though not always immediately apparent. · Clinical cardiac MRI provides numerous functional and morphological quantitative parameters.. · Quantitative cardiac MRI enables assessment of diffuse and global myocardial alterations.. · Standardized data acquisition/evaluation is the prerequisite for diagnostic use of quantitative cardiac MRI parameters..· Reiter U, Reiter C, Kräuter C et al. Quantitative Clinical Cardiac Magnetic Resonance Imaging. Fortschr Röntgenstr 2020; 192: 246 - 256. Die kardiale Magnetresonanztomografie (MRT) stellt sowohl in der Beurteilung der Herzfunktion als auch zur nichtinvasiven Gewebsanalyse des Myokards in vielen klinischen Fragestellungen die Referenz-Standard-Methode dar. Speziell die Quantifizierung kardialer Parameter nimmt eine immer zentralere diagnostische und differenzialdiagnostische Rolle ein. Im vorliegenden Review sollen etablierte und vielversprechende neue quantitative Herz-MRT-Parameter der klinischen Routine zusammengefasst, ihre Zusammenhänge beschrieben sowie ihre Abhängigkeiten von substanziellen Einflussfaktoren dargestellt werden. Die Übersichtsarbeit basiert auf einer PubMed-Literaturrecherche zu den Begriffen „cardiac magnetic resonance“ und „quantification“, „recommendations“, „quantitative evaluation/assessment“, „reference method“, „reference/normal values“, „pitfalls“ sowie „artifacts“ innerhalb des Publikationszeitraums 2000–2019. Funktionelle, Phasenkontrast- und Perfusionsbildgebung sowie Relaxationszeit-Kartierung ermöglichen die Erfassung einer Vielzahl quantitativer Herz-MRT-Parameter. Diese erlauben eine über die visuelle Beurteilung von Herz-MRT-Bildern hinausgehende Charakterisierung der Funktion, Morphologie und Perfusion des Herzens, sei es im Vergleich zu Normalwerten oder im Therapieverlauf. Bei der Interpretation ausgewerteter Herz-MRT-Parameter in der klinischen Routine muss allerdings zunehmend auf Standardisierung geachtet werden, da Aufnahmetechniken und Auswertealgorithmen quantitative Ergebnisse maßgeblich – jedoch mitunter nicht unmittelbar erkennbar – beeinflussen können. · Die Routine-Herz-MRT erlaubt die Bestimmung einer Vielzahl funktioneller und morphologischer quantitativer Parameter.. · Quantitative Herz-MRT-Parameter ermöglichen die Erfassung diffuser und globaler myokardialer Veränderungen.. · Standardisierte Aufnahmetechniken und Auswertealgorithmen sind zentrale Voraussetzung zur diagnostischen Interpretation quantitativer Herz-MRT-Parameter..· Reiter U, Reiter C, Kräuter C et al. Quantitative Clinical Cardiac Magnetic Resonance Imaging. Fortschr Röntgenstr 2020; 192: 246 – 256.

Cardiac digital twins (Cardiac Digital Twin (CDT)s) of human electrophysiology (Electrophysiology (EP)) are digital replicas of patient hearts derived from clinical data that match like-for-like all available clinical observations. Due to their inherent predictive potential, CDTs show high promise as a complementary modality aiding in clinical decision making and also in the cost-effective, safe and ethical testing of novel EP device therapies. However, current workflows for both the anatomical and functional twinning phases within CDT generation, referring to the inference of model anatomy and parameters from clinical data, are not sufficiently efficient, robust and accurate for advanced clinical and industrial applications. Our study addresses three primary limitations impeding the routine generation of high-fidelity CDTs by introducing; a comprehensive parameter vector encapsulating all factors relating to the ventricular EP; an abstract reference frame within the model allowing the unattended manipulation of model parameter fields; a novel fast-forward electrocardiogram (Electrocardiogram (ECG)) model for efficient and bio-physically-detailed simulation required for parameter inference. A novel workflow for the generation of CDTs is then introduced as an initial proof of concept. Anatomical twinning was performed within a reasonable time compatible with clinical workflows ( 4h) for 12 subjects from clinically-attained magnetic resonance images. After assessment of the underlying fast forward ECG model against a gold standard bidomain ECG model, functional twinning of optimal parameters according to a clinically-attained 12 lead ECG was then performed using a forward Saltelli sampling approach for a single subject. The achieved results in terms of efficiency and fidelity demonstrate that our workflow is well-suited and viable for generating biophysically-detailed CDTs at scale.

While an enormous number of studies have documented pathological alterations of the myocardial native longitudinal relaxation time (T1) and the fraction of the extracellular myocardial volume (ECV), it has also become clear that continuously evolving T1 mapping sequence, acquisition and evaluation techniques have a substantial impact on quantitative results, making the translation of reported findings into routine clinical use particularly challenging. To provide a basis for the discussion of pathological myocardial T1 and ECV alterations, the present review aims to summarize the methodological aspects of myocardial T1 mapping along with technical and physiological factors influencing results and normal ranges of myocardial native T1 and ECV reported across studies.

Non-invasive identification and differentiation of myocardial diseases represents the primary objectives of cardiac magnetic resonance (CMR) longitudinal relaxation time (T1) and extracellular volume (ECV) mapping. Given the fact that myocardial T1 and ECV values overlap throughout and within left ventricular phenotypes, a central issue to be addressed is whether and to what extent myocardial T1 and ECV mapping provides additional or superior diagnostic information to standard CMR imaging, and whether native T1 mapping could be employed as a non-contrast alternative to late gadolinium enhancement (LE) imaging. The present review aims to summarize physiological and pathophysiological alterations in native T1 and ECV values and summarized myocardial T1 and ECV alterations associated with cardiac diseases to support the translation of research findings into routine CMR imaging.

Background Quantification of myocardial blood flow (MBF) from dynamic contrast‐enhanced (DCE) MRI can be performed using a signal intensity model that incorporates T1 values of blood and myocardium. Purpose To assess the impact of T1 values on pixelwise MBF quantification, specifically to evaluate the influence of 1) study population‐averaged vs. subject‐specific, 2) diastolic vs. systolic, and 3) regional vs. global myocardial T1 values. Study Type Prospective. Subjects Fifteen patients with chronic coronary heart disease. Field Strength/Sequence 3T; modified Look–Locker inversion recovery for T1 mapping and saturation recovery gradient echo for DCE imaging, both acquired in a mid‐ventricular short‐axis slice in systole and diastole. Assessment MBF was estimated using Fermi modeling and signal intensity nonlinearity correction with different T1 values: study population‐averaged blood and myocardial, subject‐specific systolic and diastolic, and segmental T1 values. Myocardial segments with perfusion deficits were identified visually from DCE series. Statistical Tests The relationships between MBF parameters derived by different methods were analyzed by Bland–Altman analysis; corresponding mean values were compared by t‐test. Results Using subject‐specific diastolic T1 values, global diastolic MBF was 0.61 ± 0.13 mL/(min·g). It did not differ from global MBF derived from the study population‐averaged T1 (P = 0.88), but the standard deviation of differences was large (0.07 mL/(min·g), 11% of mean MBF). Global diastolic and systolic MBF did not differ (P = 0.12), whereas global diastolic MBF using systolic (0.62 ± 0.13 mL/(min·g)) and diastolic T1 values differed (P

To analyze differences in systolic and diastolic left ventricular (LV) as well as left atrial (LA) function parameters obtained from identical cardiac magnetic resonance (MR) imaging techniques during inspiratory breath-holding and breathing (breath-hold to breathing differences).56 subjects without signs of heart failure (23/33 male/female, age 58 ± 14 years) underwent 3 T MR cine real-time and transmitral phase contrast imaging with the same spatial and temporal resolution during inspiratory breath-holding and free breathing. LV and LA volumetric function parameters were derived from segmentation of cine series, transmitral peak velocities and early-diastolic myocardial peak velocity from phase contrast series. Corresponding breath-hold and breathing parameters were compared by Bland-Altman analysis; repeatability of breath-hold and breathing measurements was quantified by variance component analysis. p 0.05 was regarded as statistically significant.Mean differences between results obtained during inspiratory breath-holding vs. breathing were significant for LV volumetric function (end-diastolic volume=-7 mL, p = 0.002; end-systolic volume=-7 mL, p 0.001; ejection fraction = 3 %, p 0.001; peak ejection rate = 22 mL/s, p = 0.002; early-diastolic peak filling rate=-34 mL/s, p = 0.025), LA volumetric function (maximum volume=-6 mL, p 0.001; total ejection fraction=-4%, p 0.001; active ejection fraction=-2%, p = 0.013; before contraction ejection fraction=-4%, p 0.001) and early-diastolic velocities (transmitral=-6 cm/s, p 0.001; tissue velocity=-1.8 cm/s, p 0.001). Standard deviations of breath-hold-to-breathing differences exceeded the corresponding repeatabilities of breath-hold and breathing measurements.Systolic and diastolic LV and LA function parameters acquired during inspiratory breath-holding and breathing differ, and large inter-individual breath-hold-to-breathing variations are possible. Thus, the breathing state should be taken into account, especially when comparing results in patient follow-up acquired in different respiratory states.

Here, we report on the feasibility and use of magnetic resonance imaging-based methods to the study of electrohydrodynamic (EHD) liquid bridges. High-speed tomographic recordings through the longitudinal axis of water bridges were used to characterize the mass transfer dynamics, mixing, and flow structure. By filling one beaker with heavy water and the other with light water, it was possible to track the spread of the proton signal throughout the total liquid volume. The mixing kinetics are different depending on where the light nuclei are located and proceeds faster when the anolyte is light water. Distinct flow and mixing regions are identified in the fluid volumes, and it is shown that the EHD flow at the electrodes can be counteracted by the density difference between water isotopes. MR phase contrast imaging reveals that within the bridge section, two separate counter-propagating flows pass one above the other in the bridge.

To analyze alterations in left ventricular (LV) myocardial T1 times in patients with pulmonary hypertension (PH) and to investigate their associations with ventricular function, mass, geometry and hemodynamics. Fifty-eight patients with suspected PH underwent right heart catheterization (RHC) and 3T cardiac magnetic resonance imaging. Ventricular function, geometry and mass were derived from cine real-time short-axis images. Myocardial T1 maps were acquired by a prototype modified Look-Locker inversion-recovery sequence in short-axis orientations. LV global, segmental and ventricular insertion point (VIP) T1 times were evaluated manually and corrected for blood T1. Septal, lateral, global and VIP T1 times were significantly higher in PH than in non-PH subjects (septal, 1249 ± 58 ms vs. 1186 ± 33 ms, p

Introduction: The study aimed to validate formulas from the literature calculating mean pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR) from cardiac magnetic resonance (CMR)-derived measures in our prospective cohort of pulmonary hypertension (PH) patients (n=77) and patients at risk of PH (n=38). Methods: Literature research revealed multiple CMR-derived measures of PAP and PVR, based on main pulmonary artery area, blood flow velocity, its product (Q), ventricular mass index, stroke volume, and multiparametric models including right ventricular ejection fraction (PAPMR=Area min/RVEF, Moral, S. et al. Int J Cardiol 2012;161:25-30; PVRMR=19.38-(4.62xln(velocity;mean, avgerage)-(0.08xRVEF), Garcia-Alvarez, A. et al. Eur Heart J 2011;32:2438-45). All our patients underwent CMR and RHC and the formulas from the literature research were applied to our data. Results: We included 115 patients with complete CMR and RHC data (PH group: n=31 pulmonary arterial hypertension, n=9 left heart disease, n=16 lung disease, n=15 chronic thromboembolic disease, n=6 other). We found significant correlations, according to the literature formula, with r values ranging from 0.43 to 0.72 for PAP and 0.26 to 0.75 for PVR. The best correlations were found using the multiparametric models described above (r=0.72, and r=0.75, for PAP and PVR, respectively). The correlations found in the original cohorts were r=0.61 and r=0.84, respectively. Conclusions: In our prospective cohort, the literature-based formulas for calculation of PAP and PVR based on CMR-based measures could largely be validated. The best correlations were derived from multiparametric formulas including right ventricular ejection fraction.

To introduce blood normalization for myocardial T1 values at magnetic resonance (MR) imaging and to evaluate regional differences between systolic and diastolic myocardial T1 values in healthy subjects.This prospective study (ClinicalTrials.gov identification number, NCT01728597) was approved by the institutional review board, and volunteer informed consent was obtained. Forty healthy subjects (20 women; age range, 20-35 years) underwent electrocardiographically gated 1.5-T MR imaging. A modified Look-Locker inversion recovery sequence was used to acquire myocardial T1 maps in systole and diastole. Regional T1 values were evaluated in 16 myocardial segments; blood T1 was derived from the blood pool in the center of the left ventricular cavity. Linear regression slopes between myocardial and blood T1 values were used to normalize myocardial T1 to the mean blood T1 of the study population. Mean T1 values were compared by using the t test, with P.05 considered to indicate a significant difference.Mean myocardial T1 (984 msec ± 28 [standard deviation] in diastole, 959 msec ± 21 in systole) and all segmental T1 values between diastole and systole differed significantly (P.001). Blood T1 correlated well with segmental myocardial T1 (R = 0.73 for diastole, R = 0.72 for systole). After normalization to blood T1, significant sex differences in myocardial T1 disappeared and variances in mean myocardial T1 decreased. Blood-normalized diastolic and systolic myocardial T1 values correlated strongly with each other on segmental (r = 0.72) and global (r = 0.89) levels. Subregional myocardial T1 distribution characteristics in diastole were similar to those in systole.In normal myocardium, diastolic and systolic myocardial T1 values differ significantly but correlate strongly. Blood normalization eliminates sex differences in myocardial T1 values and reduces their variability.

Background Red blood cells (RBCs) are routinely stored in liquid state at temperatures below 6°C, and RBC unit core temperature should not exceed 10°C during transport. Since the critical temperature of 10°C was chosen mostly arbitrarily, this study investigated the effect of both constant temperature settings as well as multiple rewarming cycles on stored RBCs with respect to morphology, biochemical parameters and haemolysis. Materials and Methods Buffy coat-depleted filtered RBCs were used as standard products. RBCs were stored at 1–6°C (reference group, n = 12), 13 and 22°C (test groups, n = 12 each) or stored at 1–6°C and warmed up five times to 10, 13, or 22°C for a period of 24 h each. Various biochemical parameters were measured weekly. RBCs were further investigated using electron microscopy. Results Red blood cells stored constantly at 13 or 22°C showed stable haemolysis rates until day 28 and day 14, respectively. RBCs stored at 1–6°C with five warming-up periods to 10, 13 or 22°C each lasting 24 h (total 120 h) did not exceed the limit of the haemolysis rate at the end of storage. Differently shaped erythrocytes were found in all samples, but more crenate erythrocytes appeared after 42 days of storage independent of temperature profiles. Conclusion Red cells can be kept at constant temperatures above 6°C without apparent harmful effects at least until day 14, whereas multiple warming cycles for no longer than 24 h at 10, 13 or 22°C with subsequent cooling do not cause quality loss as assessed using the in vitro assays employed in this study.

Background: The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated pig (hereafter, DOCA pig) was recently introduced as large animal model for early-stage heart failure with preserved ejection fraction (HFpEF). The aim of the present study was to evaluate cardiovascular magnetic resonance (CMR) of DOCA pigs and weight-matched control pigs to characterize ventricular, atrial and myocardial structure and function of this phenotype model.Methods: Five anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during dobutamine stress. Left ventricular/atrial (LV/LA) function and myocardial mass (LVMM), strains and torsion were evaluated from (tagged) cine imaging. 4D phase-contrast measurements were used to assess blood flow and peak velocities, including transmitral early-diastolic (E) and myocardial tissue (E’) velocities and coronary sinus blood flow. Myocardial perfusion reserve was estimated from stress-to-rest time-averaged coronary sinus flow. Global native myocardial T1 times were derived from prototype modified Look-Locker inversion-recovery (MOLLI) short-axis T1 maps. After in-vivo measurements, transmural biopsies were collected for stereological evaluation including the volume fractions of interstitium (VV(int/LV)) and collagen (VV(coll/LV)). Rest, stress, and stress-to-rest differences of cardiac and myocardial parameters in DOCA and control animals were compared by t-test.Results: In DOCA pigs LVMM (p p = 0.003/p = 0.007) were elevated. During stress, increase of LV ejection-fraction and decrease of end-systolic volume accounted for normal contractility reserves in DOCA and control pigs. Rest-to-stress differences of cardiac index (p = 0.040) and end-diastolic volume (p = 0.042) were documented. Maximal (p = 0.042) and minimal (p = 0.012) LA volumes in DOCA pigs were elevated at rest; total LA ejection-fraction decreased during stress (p = 0.006). E’ was lower in DOCA pigs, corresponding to higher E/E’ at rest (p = 0.013) and stress (p = 0.026). Myocardial perfusion reserve was reduced in DOCA pigs (p = 0.031). T1-times and VV(int/LV) did not differ between groups, whereas VV(coll/LV) levels were higher in DOCA pigs (p = 0.044).Conclusions: LA enlargement, E’ and E/E’ were the markers that showed the most pronounced differences between DOCA and control pigs at rest. Inadequate increase of myocardial perfusion reserve during stress might represent a metrics for early-stage HFpEF. Myocardial T1 mapping could not detect elevated levels of myocardial collagen in this model.Trial registration: The study was approved by the local Bioethics Committee of Vienna, Austria (BMWF-66.010/0091-II/3b/2013).

Background In patients with pulmonary hypertension (PH), duration of vortical blood flow along the main pulmonary artery enables estimation of the mean pulmonary arterial pressure (mPAP) non-invasively. It remains to date not known, if this method is applicable in patients with pulmonary arterial hypertension (PAH) and abnormal aortic-to-pulmonary shunting. Case presentation The present case analyzes the effect of a patent ductus arteriosus (PDA) on pulmonary artery flow patterns in PAH (mPAP from right heart catheterization, 75 mmHg). PH-associated vortical blood flow, which is typically observed rotating in a clockwise direction when viewed in right ventricular outflow tract orientation, was found nested in PDA left-to-right shunting. Even though rotating counter-clockwise, duration of vortical flow translated into correct non-invasive mPAP estimate. Conclusions This case indicates that PH-associated vortex rotation is not restricted to clockwise direction, and that vortex-based estimation of elevated mPAP might also be feasible in patients with PAH and PDA. Electronic supplementary material The online version of this article (doi:10.1186/s12880-016-0150-z) contains supplementary material, which is available to authorized users.

Pulmonary hypertension (PH) is a life-threatening, multifactorial pathophysiological haemodynamic condition, diagnosed when the mean pulmonary arterial pressure equals or exceeds 25 mmHg at rest during right heart catheterization. Cardiac MRI, in general, and MR phase-contrast (PC) imaging, in particular, have emerged as potential techniques for the standardized assessment of cardiovascular function, morphology and haemodynamics in PH. Allowing the quantification and characterization of macroscopic cardiovascular blood flow, MR PC imaging offers non-invasive evaluation of haemodynamic alterations associated with PH. Techniques used to study the PH include both the routine two-dimensional (2D) approach measuring predominant velocities through an acquisition plane and the rapidly evolving four-dimensional (4D) PC imaging, which enables the assessment of the complete time-resolved, three-directional blood-flow velocity field in a volume. Numerous parameters such as pulmonary arterial mean velocity, vessel distensibility, flow acceleration time and volume and tricuspid regurgitation peak velocity, as well as the duration and onset of vortical blood flow in the main pulmonary artery, have been explored to either diagnose PH or find non-invasive correlates to right heart catheter parameters. Furthermore, PC imaging-based analysis of pulmonary arterial pulse-wave velocities, wall shear stress and kinetic energy losses grants novel insights into cardiopulmonary remodelling in PH. This review aimed to outline the current applications of 2D and 4D PC imaging in PH and show why this technique has the potential to contribute significantly to early diagnosis and characterization of PH.

BACKGROUND: Recommended by current guidelines, red blood cell (RBC) temperature should not exceed 10°C during transport. Since warming is a generically three-dimensional process that is not homogeneous, it is necessary to clarify the term “temperature during warming.” The purpose of this study was therefore to investigate laws and relations between surface, mean, and core temperature and the corresponding times when they exceed 10°C during warm-up. STUDY DESIGN AND METHODS: Time-resolved three-dimensional temperature distributions of 53 resuspended RBC units (mean volume, 253 ± 17 mL) were measured noninvasively by magnetic resonance thermometry. Warm-up temperature maps were visualized and analyzed by dedicated software. RESULTS: Mean times when surface, mean, and core temperature exceeded 10°C were 16 ± 4, 24 ± 5, and 36 ± 7 minutes, respectively. Times strongly correlated with each other (r = 0.78-0.95) and their variances mainly depended on RBC storage temperature and RBC pouch width (R2 = 0.81-0.89). Measured mean temperature time courses were well described by a lumped capacitive model of heat transfer with a sample width-dependent time constant τRBC = 56.3 ± 3.5 minutes (mean R2 = 0.996). CONCLUSION: Times when RBC surface, mean, and core temperature exceed 10°C can be estimated from each other. Moreover RBC mean temperature can be calculated for arbitrary storage and ambient temperatures. Findings might serve as a helpful tool in RBC temperature monitoring.

BACKGROUND: Radiofrequency identification (RFID) technology is emerging as one of the most pervasive computing technologies due to its broad applicability. Storage of red blood cells (RBCs) is a routine procedure worldwide. Depending on the additive solution, RBCs can be stored at 4 ± 2°C up to 49 days. To support the decision of discarding or further using a blood product, temperature measurement of each unit could be provided by RFID application. The safety evaluation of RFID devices was demonstrated in a regulatory agency required study. It has been concluded in limit tests that high frequency–based RFID technology performed safely for blood products; therefore, a longer exposure of radiofrequency (RF) energy on blood units was performed in this study to detect any biologic effects in RBC samples. STUDY DESIGN AND METHODS: Buffy coat–depleted, in line–filtered RBCs were used as standard products in all tests. Various variables like pH, potassium, glucose, lactate, hemoglobin (Hb), hematocrit, free Hb, and hemolysis rate were measured in a test group with RFID tags placed on their surface and continuously radiated with 13.56-MHz RFID reader radiation for 42 days while stored at 4 ± 2°C and compared to a control group by two-sample t test. RESULTS: In both groups glucose and pH levels decreased while lactate, free Hb, and potassium increased within the expected levels. The hemolysis rate showed increase after the 25th day but remained below the maximum acceptable threshold of 0.8%. CONCLUSION: It is feasible to implement RFID-enabled processes, without detecting any known biologic effects of longer exposure of RF energy on the quality of RBCs.

Background and Objectives Temperature tracing of stored red-blood-cell concentrates (RBCs) is inevitable with respect to RBC quality control. RBC temperature, which should not exceed 10°C, is usually assessed by devices attached to the surface of the RBC pouch, assuming that surface temperature adequately represents the thermal state of RBC. We investigated under which conditions this assumption is true. Materials and Methods Eighteen thermocouples (TC) equidistantly mounted on a two-layer plastic grid were installed in a pouch to determine temperature distribution in the unit. Two TCs were attached to each side of the bag to evaluate surface temperatures. One was further installed in each investigation room to assess ambient room temperatures. Temperature distributions and time–temperature courses were measured under constant temperatures and various warming and cooling conditions. Results At homogeneous storage temperatures, only small gradients were measured between core and surface temperatures. Removed from cooling chamber to room temperature or back from room to storage temperature, core and surface time–temperature curves drifted apart. Surface and core temperature diverged the more, the faster ambient temperatures altered. The situation could be stabilized by thermal isolation: handled in a transport box, or even better in an air cushion envelope, surface and core courses approached and ultimately closely followed each other, respectively. Conclusion RBC temperature monitoring devices attached to the surface of the RBC pouch very well describe the core temperature under constant temperature conditions. During transport, thermal isolation of the RBC unit is necessary to control RBC temperature precisely by surface temperature measurements.

To approximate the functional relationship between invasively measured mean pulmonary arterial pressure (mPAP) and the phase-contrast magnetic resonance (MR) imaging-derived duration of vortical blood flow along the main pulmonary artery and to analyze its applicability for noninvasive diagnosis of pulmonary hypertension (PH) and borderline mPAP.The local ethics review board approved this prospective study of 145 patients suspected of having PH (69 patients with PH, 19 patients with borderline mPAP, and 57 patients with normal mPAP) who underwent right heart catheterization (RHC) and three-directional phase-contrast MR imaging of the main pulmonary artery. Velocity fields were viewed with dedicated software and evaluated for the duration of vortical blood flow in the main pulmonary artery (tvortex, the percentage of cardiac phases with vortex present). The relationship between mPAP at RHC and tvortex was assessed by means of a segmented linear regression model, and by Bland-Altman and receiver operating characteristic curve analyses.The relationship between mPAP and tvortex was described adequately (R(2) = 0.95) as linearly increasing, from tvortex of 0% (mPAP ≤ 16.0 mm Hg) with a slope of 1.59% per millimeter of mercury. The standard deviation between mPAP values derived from RHC and those estimated by using tvortex was 3.9 mm Hg. The area under the curve for tvortex-based diagnosis of PH was 0.994 (95% confidence interval [CI]: 0.982, 0.998), and the calculated PH cut-off value (tvortex ≥ 14.3%) resulted in sensitivity of 0.97 (95% CI: 0.90, 0.99) and specificity of 0.96 (95% CI: 0.89, 0.99). Vortical blood flow with tvortex less than 14.3% was specific for borderline mPAP.Duration of vortical blood flow in the main pulmonary artery that is determined by using phase-contrast MR imaging allows accurate estimation of elevated mPAP and diagnosis of PH. Clinical trial registration no. NCT00575692.

The clinical role of magnetic resonance in diseases of the heart and great vessels is rapidly evolving. Cardiovascular magnetic resonance (CMR) has become an established non-invasive imaging modality for the assessment of various cardiac disorders, such as congenital heart disease, cardiac masses, cardiomyopathies, aortic and pericardial diseases. Moreover, due to its accuracy and reproducibility, CMR is currently considered the gold standard for quantification of ventricular volumes, function, and mass. Thus, this technique is ideally suited to assess the efficacy of therapeutic interventions on ventricular hypertrophy and remodelling, which may allow a reduction in sample size to show clinically relevant effects. Comprehensive functional assessment is possible by CMR due to its capability to measure flow velocity and flow volume, which is a basic requirement to quantify lesion severity in valvular heart disease. Within the past years, major technical advances have considerably improved acquisition speed and image quality making CMR a useful tool for the evaluation of patients with ischaemic heart disease. Although the clinical robustness of coronary magnetic resonance angiography still needs improvement, CMR currently provides valuable information to detect reversible ischemia, myocardial infarction, and residual viability. In this review we will present in detail the well-established indications of CMR accompanied by an outlook on new applications that are likely to enter the clinical arena in the near future.

Purpose Three-dimensional (3D) magnetic resonance phase contrast imaging (PC-MRI) allows non-invasive diagnosis of pulmonary hypertension (PH) and estimation of elevated mean pulmonary arterial pressure (mPAP) based on vortical motion of blood in the main pulmonary artery. The purpose of the present study was to compare the presence and duration of PH-associated vortices derived from different flow visualization techniques with special respect to their performance for non-invasive assessment of elevated mPAP and diagnosis of PH. Methods Fifty patients with suspected PH (23 patients with and 27 without PH) were investigated by right heart catheterization and time-resolved PC-MRI of the main pulmonary artery. PC-MRI data were visualized with dedicated prototype software, providing 3D vector, multi-planar reformatted (MPR) 2D vector, streamline, and particle trace representation of flow patterns. Persistence of PH-associated vortical blood flow (tvortex) was evaluated with all visualization techniques. Dependencies of tvortex on visualization techniques were analyzed by means of correlation and receiver operating characteristic (ROC) curve analysis. Results tvortex values from 3D vector visualization correlated strongly with those from other visualization techniques (r = 0.98, 0.98 and 0.97 for MPR, streamline and particle trace visualization, respectively). Areas under ROC curves for diagnosis of PH based on tvortex did not differ significantly and were 0.998 for 3D vector, MPR vector and particle trace visualization and 0.999 for streamline visualization. Correlations between elevated mPAP and tvortex in patients with PH were r = 0.96, 0.93, 0.95 and 0.92 for 3D vector, MPR vector, streamline and particle trace visualization, respectively. Corresponding standard deviations from the linear regression lines ranged between 3 and 4 mmHg. Conclusion 3D vector, MPR vector, streamline as well as particle trace visualization of time-resolved 3D PC-MRI data of the main pulmonary artery can be employed for accurate vortex-based diagnosis of PH and estimation of elevated mPAP.

Background Even though intra-cardiac cystic lesions are extremely unusual in adults, they should be considered in the differential diagnosis of patients presenting with valvular masses. Cardiac magnetic resonance imaging has emerged as modality of choice for non-invasive characterization of cardiac masses. Case presentation We report a case of an intra-cardiac mass of the mitral valve in a 51-year old male, detected by echocardiography after transient ischemic attack and retinal artery occlusion. Cardiac magnetic resonance (CMR) imaging was performed at 3 T to evaluate and characterize the lesion prior to surgery. Diagnosis of a calcified left-ventricular pseudocyst of the mitral valve was confirmed by histological evaluation. Conclusions This case presents the unusual finding of contrast uptake in an intra-cardiac cystic lesion and points to the potential of T1 and T2 mapping for assisting in the characterization and diagnosis of intra-cardiac masses by CMR.

P levels. A numerical model developed to describe mechanisms involved in the conical emission generation processes indicates that the saturation observed is due to the opposite angular tuning of the near-infrared and yellow conical emission generated in the same process. The mechanisms responsible are assigned to (self)induced phase modulation processes of the waves involved.

Objectives To assess the correlation of relative hepatic enhancement (RHE), relative renal enhancement (RRE) and liver to kidneys enhancement ratio (LKR) with serum hepatic enzyme levels and eGFR in Gd-EOB-DTPA enhanced MRI of the liver and to assess threshold levels for predicting enhancement of the liver parenchyma. Methods Data of 75 patients who underwent Gd-EOB-DTPA enhanced MRI of the liver were collected. Images were obtained before contrast injection, during the early arterial phase, late arterial phase, venous phase, delayed phase, and hepatobiliary phase which was 20 min after Gd-EOB-DTPA administration. Signal intensity of the liver and the kidneys in all phases was defined using region-of-interest measurements for relative enhancement calculation. Serum hepatic enzyme levels and eGFR were available in all patients. Spearman correlation test was used to test the correlation of RHE, RRE and LKR with serum hepatic enzyme levels and eGFR. Results In the hepatobiliary phase all serum hepatic enzymes were significantly correlated with RHE; total bilirubin (TBIL) and cholin esterase (CHE) showed strongest correlations. TBIL and CHE were significantly correlated with RRE in the arterial phases. TBIL and CHE were significantly correlated with LKR in the arterial phase and hepatobiliary phase. eGFR showed no correlation. Conclusions In Gd-EOB-DTPA enhanced MRI, TBIL and CHE levels may predict RHE, RRE and LKR.

Radiofrequency identification (RFID) technology is emerging as one of the most pervasive computing technologies due to its broad applicability. Storage of red blood cells (RBCs) is a routine procedure worldwide. Depending on the additive solution, RBCs can be stored at 4 ± 2°C up to 49 days. To support the decision of discarding or further using a blood product, temperature measurement of each unit could be provided by RFID application. The safety evaluation of RFID devices was demonstrated in a regulatory agency required study. It has been concluded in limit tests that high frequency-based RFID technology performed safely for blood products; therefore, a longer exposure of radiofrequency (RF) energy on blood units was performed in this study to detect any biologic effects in RBC samples.Buffy coat-depleted, in line-filtered RBCs were used as standard products in all tests. Various variables like pH, potassium, glucose, lactate, hemoglobin (Hb), hematocrit, free Hb, and hemolysis rate were measured in a test group with RFID tags placed on their surface and continuously radiated with 13.56-MHz RFID reader radiation for 42 days while stored at 4 ± 2°C and compared to a control group by two-sample t test.In both groups glucose and pH levels decreased while lactate, free Hb, and potassium increased within the expected levels. The hemolysis rate showed increase after the 25th day but remained below the maximum acceptable threshold of 0.8%.It is feasible to implement RFID-enabled processes, without detecting any known biologic effects of longer exposure of RF energy on the quality of RBCs.

Background—Pulmonary hypertension is a disease characterized by an elevation in pulmonary arterial pressure that is diagnosed invasively via right heart catheterization. Such pathological altered pressures in the pulmonary vascular system should lead to changes in blood flow patterns in the main pulmonary artery.Methods and Results—Forty-eight subjects (22 with manifest pulmonary hypertension, 13 with latent pulmonary hypertension, and 13 normal control subjects) underwent time-resolved 3D magnetic resonance phase-contrast imaging of the main pulmonary artery. Velocity fields that resulted from measurements were calculated, visualized, and analyzed with dedicated software. Main findings were as follows: (1) Manifest pulmonary hypertension coincides with the appearance of a vortex of blood flow in the main pulmonary artery (sensitivity and specificity of 1.00, 95% confidence intervals of 0.84 to 1.00 and 0.87 to 1.00, respectively), and (2) the relative period of existence of the vortex correlates significantly with mean pulmonary arterial pressure at rest (correlation coefficient of 0.94). To test the diagnostic performance of the vortex criterion, we furthermore investigated 55 patients in a blinded prospective study (22 with manifest pulmonary hypertension, 32 with latent pulmonary hypertension, and 1 healthy subject), which resulted in a sensitivity of 1.00 and specificity of 0.91 (95% confidence intervals of 0.84 to 1.00 and 0.76 to 0.98, respectively). Comparison of catheter-derived mean pulmonary artery pressure measurements and calculated mean pulmonary artery pressure values resulted in a standard deviation of differences of 3.6 mm Hg.Conclusions—Vortices of blood flow in the main pulmonary artery enable the identification of manifest pulmonary hypertension. Elevated mean pulmonary arterial pressures can be measured from the period of vortex existence.