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Purpose To investigate the accuracy, reproducibility and sensitivity to respiratory gating, field strength and ventricle segmentation of hemodynamic force quantification in the left and right ventricles of the heart (LV and RV) using 4D-flow magnetic resonance imaging (MRI), and to provide free hemodynamic force analysis software. Materials and methods A pulsatile flow phantom was imaged using 4D flow MRI and laser-based particle image velocimetry (PIV). Cardiac 4D flow MRI was performed in healthy volunteers at 1.5T (n = 23). Reproducibility was investigated using MR scanners from two different vendors on the same day (n = 8). Subsets of volunteers were also imaged without respiratory gating (n = 17), at 3T on the same day (n = 6), and 1–12 days later on the same scanner (n = 9, median 6 days). Agreement was measured using the intraclass correlation coefficient (ICC). Results Phantom validation showed good accuracy for both scanners (Scanner 1: bias -14±9%, y = 0.82x+0.08, R2 = 0.96, Scanner 2: bias -12±8%, y = 0.99x-0.08, R2 = 1.00). Force reproducibility was strong in the LV (0.09±0.07 vs 0.09±0.07 N, bias 0.00±0.04 N, ICC = 0.87) and RV (0.09±0.06 vs 0.09±0.05 N, bias 0.00±0.03, ICC = 0.83). Strong to very strong agreement was found for scans with and without respiratory gating (LV/RV: ICC = 0.94/0.95), scans on different days (ICC = 0.92/0.87), and 1.5T and 3T scans (ICC = 0.93/0.94). Conclusion Software for quantification of hemodynamic forces in 4D-flow MRI was developed, and results show high accuracy and strong to very strong reproducibility for both the LV and RV, supporting its use for research and clinical investigations. The software including source code is released freely for research. (Less)

Four-dimensional (4D) flow magnetic resonance imaging (MRI) enables quantification of kinetic energy (KE) in intraventricular blood flow. This provides a novel way to understand the cardiovascular physiology of the Fontan circulation. In this study, we aimed to quantify the KE in functional single ventricles. 4D flow MRI was acquired in eleven patients with Fontan circulation (median age 12 years, range 3–29) and eight healthy volunteers (median age 26 years, range 23–36). Follow-up MRI after surgical or percutaneous intervention was performed in 3 patients. Intraventricular KE was calculated throughout the cardiac cycle and indexed to stroke volume (SV). The systolic/diastolic ratio of KE in Fontan patients was similar to the ratio of the controls’ left ventricle (LV) or right ventricle (RV) depending on the patients’ ventricular morphology (Cohen´s κ = 1.0). Peak systolic KE/SV did not differ in patients compared to the LV in controls (0.016 ± 0.006 mJ/ml vs 0.020 ± 0.004 mJ/ml, p = 0.09). Peak diastolic KE/SV in Fontan patients was lower than in the LV of the control group (0.028 ± 0.010 mJ/ml vs 0.057 ± 0.011 mJ/ml, p

Intraventricular pressure gradients or hemodynamic forces, which are their global measure integrated over the left ventricular volume, have a fundamental importance in ventricular function. They may help revealing a sub-optimal cardiac function that is not evident in terms of tissue motion, which is naturally heterogeneous and variable, and can influence cardiac adaptation. However, hemodynamic forces are not utilized in clinical cardiology due to the unavailability of simple non-invasive measurement tools. Hemodynamic forces depend on the intraventricular flow; nevertheless, most of them are imputable to the dynamics of the endocardial flow boundary and to the exchange of momentum across the mitral and aortic orifices. In this study, we introduce a simplified model based on first principles of fluid dynamics that allows estimating hemodynamic forces without knowing the velocity field inside the LV. The model is validated with 3D phase-contrast MRI (known as 4D flow MRI) in 15 subjects, (5 healthy and 10 patients) using the endocardial surface reconstructed from the three standard long-axis projections. Results demonstrate that the model provides consistent estimates for the base-apex component (mean correlation coefficient r = 0.77 for instantaneous values and r = 0.88 for root mean square) and good estimates of the inferolateral-anteroseptal component (r = 0.50 and 0.84, respectively). The present method represents a potential integration to the existing ones quantifying endocardial deformation in MRI and echocardiography to add a physics-based estimation of the corresponding hemodynamic forces. These could help the clinician to early detect sub-clinical diseases and differentiate between different cardiac dysfunctional states.

Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only left ventricular (LV) forces. Right ventricular (RV) forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify 3D hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. Twenty five controls, 14 elite endurance athletes, and 2 patients with LV dyssynchrony were included. 4D flow data were used as input for the Navier-Stokes equations to compute hemodynamic forces over the entire cardiac cycle. Hemodynamic forces were found in a qualitatively consistent pattern in all healthy subjects, with variations in amplitude. LV forces were mainly aligned along the apical-basal longitudinal axis, with an additional component aimed toward the aortic valve during systole. Conversely, RV forces were found in both longitudinal and short-axis planes, with a systolic force component driving a slingshot-like acceleration that explains the mechanism behind the redirection of blood flow toward the pulmonary valve. No differences were found between controls and athletes when indexing forces to ventricular volumes, indicating that cardiac force expenditures are tuned to accelerate blood similarly in small and large hearts. Patients’ forces differed from controls in both timing and amplitude. Normal cardiac pumping is associated with specific force patterns for both ventricles, and deviation from these forces may be a sensitive marker of ventricular dysfunction. Reference values are provided for future studies.NEW & NOTEWORTHY Biventricular hemodynamic forces were quantified for the first time in healthy controls and elite athletes (n = 39). Hemodynamic forces constitute a slingshot-like mechanism in the right ventricle, redirecting blood flow toward the pulmonary circulation. Force patterns were similar between healthy subjects and athletes, indicating potential utility as a cardiac function biomarker.

The study by Stokke et al. [(1)][1] notes that circumferential strain contributes more than twice as much as longitudinal strain to left ventricular ejection fraction, but previous research has shown that 60% of stroke volume is generated by left ventricular longitudinal function [(2)][2]. The

Background Time-resolved three-dimensional, three-directional phase-contrast magnetic resonance velocity mapping (4D PC-MRI) is a powerful technique to depict dynamic blood flow patterns in the human body. However, the impact of phase background effects on flow visualizations has not been thoroughly studied previously, and it has not yet been experimentally demonstrated to what degree phase offsets affect flow visualizations and create errors such as inaccurate particle traces. Purpose To quantify background phase offsets and their subsequent impact on particle trace visualizations in a 4D PC-MRI sequence. Additionally, we sought to investigate to what degree visualization errors are reduced by background phase correction. Material and Methods A rotating phantom with a known velocity field was used to quantify background phase of 4D PC-MRI sequences accelerated with SENSE as well as different k-t BLAST speed-up factors. The deviation in end positions between particle traces in the measured velocity fields were compared before and after the application of two different phase correction methods. Results Phantom measurements revealed background velocity offsets up to 7 cm/s (7% of velocity encoding sensitivity) in the central slice, increasing with distance from the center. Background offsets remained constant with increasing k-t BLAST speed-up factors. End deviations of up to 5.3 mm (1.8 voxels) in the direction perpendicular to the rotating disc were found between particle traces and the seeding plane of the traces. Phase correction by subtraction of the data from the stationary phantom reduced the average deviation by up to 56%, while correcting the data-set with a first-order polynomial fit to stationary regions decreased average deviation up to 78%. Conclusion Pathline visualizations can be significantly affected by background phase errors, highlighting the importance of dedicated and robust phase correction methods. Our results show that pathline deviation can be substantial if adequate phase background errors are not minimized.

To develop and assess a technique for self-gated fetal cardiac cine magnetic resonance imaging (MRI) using tiny golden angle radial sampling combined with iGRASP (iterative Golden-angle RAdial Sparse Parallel) for accelerated acquisition based on parallel imaging and compressed sensing.Fetal cardiac data were acquired from five volunteers in gestational week 29-37 at 1.5T using tiny golden angles for eddy currents reduction. The acquired multicoil radial projections were input to a principal component analysis-based compression stage. The cardiac self-gating (CSG) signal for cardiac gating was extracted from the acquired radial projections and the iGRASP reconstruction procedure was applied. In all acquisitions, a total of 4000 radial spokes were acquired within a breath-hold of less than 15 seconds using a balanced steady-state free precession pulse sequence. The images were qualitatively compared by two independent observers (on a scale of 1-4) to a single midventricular cine image from metric optimized gating (MOG) and real-time acquisitions.For iGRASP and MOG images, good overall image quality (2.8 ± 0.4 and 2.6 ± 1.3, respectively, for observer 1; 3.6 ± 0.5 and 3.4 ± 0.9, respectively, for observer 2) and cardiac diagnostic quality (3.8 ± 0.4 and 3.4 ± 0.9, respectively, for observer 1; 3.6 ± 0.5 and 3.6 ± 0.9, respectively, for observer 2) were obtained, with visualized myocardial thickening over the cardiac cycle and well-defined myocardial borders to ventricular lumen and liver/lung tissue. For iGRASP, MOG, and real time, left ventricular lumen diameter (14.1 ± 2.2 mm, 14.2 ± 1.9 mm, 14.7 ± 1.1 mm, respectively) and wall thickness (2.7 ± 0.3 mm, 2.6 ± 0.3 mm, 3.0 ± 0.4, respectively) showed agreement and no statistically significant difference was found (all P 0.05). Images with iGRASP tended to have higher overall image quality scores compared with MOG and particularly real-time images, albeit not statistically significant in this feasibility study (P 0.99 and P = 0.12, respectively).Fetal cardiac cine MRI can be performed with iGRASP using tiny golden angles and CSG. Comparison with other fetal cardiac cine MRI methods showed that the proposed method produces high-quality fetal cardiac reconstructions.2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:207-217.

Background— Contrast-enhanced steady state free precession (CE-SSFP) and T2-weighted short tau inversion recovery (T2-STIR) have been clinically validated to estimate myocardium at risk (MaR) by cardiovascular magnetic resonance while using myocardial perfusion single-photon emission computed tomography as reference standard. Myocardial perfusion single-photon emission computed tomography has been used to describe the coronary perfusion territories during myocardial ischemia. Compared with myocardial perfusion single-photon emission computed tomography, cardiovascular magnetic resonance offers superior image quality and practical advantages. Therefore, the aim was to describe the main coronary perfusion territories using CE-SSFP and T2-STIR cardiovascular magnetic resonance data in patients after acute ST-segment–elevation myocardial infarction. Methods and Results— CE-SSFP and T2-STIR data from 2 recent multicenter trials, CHILL-MI and MITOCARE (n=215), were used to assess MaR. Angiography was used to determine culprit vessel. Of 215 patients, 39% had left anterior descending artery occlusion, 49% had right coronary artery occlusion, and 12% had left circumflex artery occlusion. Mean extent of MaR using CE-SSFP was 44±10% for left anterior descending artery, 31±7% for right coronary artery, and 30±9% for left circumflex artery. Using T2-STIR, MaR was 44±9% for left anterior descending artery, 30±8% for right coronary artery, and 30±12% for left circumflex artery. MaR was visualized in polar plots, and expected overlap was found between right coronary artery and left circumflex artery. Detailed regional data are presented for use in software algorithms as a priori information on the extent of MaR. Conclusions— For the first time, cardiovascular magnetic resonance has been used to show the main coronary perfusion territories using CE-SSFP and T2-STIR. The good agreement between CE-SSFP and T2-STIR from this study and myocardial perfusion single-photon emission computed tomography from previous studies indicates that these 3 methods depict MaR accurately in individual patients and at a group level. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifiers: NCT01379261 and NCT01374321.

Background: Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) using magnitude inversion recovery (IR) or phase sensitive inversion recovery (PSIR) has become clinical standard for assessment of myocardial infarction (MI). However, there is no clinical standard for quantification of MI even though multiple methods have been proposed. Simple thresholds have yielded varying results and advanced algorithms have only been validated in single center studies. Therefore, the aim of this study was to develop an automatic algorithm for MI quantification in IR and PSIR LGE images and to validate the new algorithm experimentally and compare it to expert delineations in multi-center, multi-vendor patient data.Methods: The new automatic algorithm, EWA (Expectation Maximization, weighted intensity, a priori information), was implemented using an intensity threshold by Expectation Maximization (EM) and a weighted summation to account for partial volume effects.The EWA algorithm was validated in-vivo against triphenyltetrazolium-chloride (TTC) staining (n = 7 pigs with paired IR and PSIR images) and against ex-vivo high resolution T1-weighted images (n = 23 IR and n = 13 PSIR images). The EWA algorithm was also compared to expert delineation in 124 patients from multi-center, multi-vendor clinical trials 2–6 days following first time ST-elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI) (n = 124 IR and n = 49 PSIR images).Results: Infarct size by the EWA algorithm in vivo in pigs showed a bias to ex-vivo TTC of −1 ± 4%LVM (R = 0.84) in IR and −2 ± 3%LVM (R = 0.92) in PSIR images and a bias to ex-vivo T1-weighted images of 0 ± 4%LVM (R = 0.94) in IR and 0 ± 5%LVM (R = 0.79) in PSIR images. In multi-center patient studies, infarct size by the EWA algorithm showed a bias to expert delineation of −2 ± 6 %LVM (R = 0.81) in IR images (n = 124) and 0 ± 5%LVM (R = 0.89) in PSIR images (n = 49).Conclusions: The EWA algorithm was validated experimentally and in patient data with a low bias in both IR and PSIR LGE images. Thus, the use of EM and a weighted intensity as in the EWA algorithm, may serve as a clinical standard for the quantification of myocardial infarction in LGE CMR images.Clinical trial registration: CHILL-MI: NCT01379261 . MITOCARE: NCT01374321 .

Background Cardiac magnetic resonance ( CMR ) can quantify myocardial infarct ( MI ) size and myocardium at risk (MaR), enabling assessment of myocardial salvage index ( MSI ). We assessed how MSI impacts the number of patients needed to reach statistical power in relation to MI size alone and levels of biochemical markers in clinical cardioprotection trials and how scan day affect sample size. Methods and Results Controls (n=90) from the recent CHILL ‐ MI and MITOCARE trials were included. MI size, MaR, and MSI were assessed from CMR . High‐sensitivity troponin T (hsTnT) and creatine kinase isoenzyme MB ( CKMB ) levels were assessed in CHILL ‐ MI patients (n=50). Utilizing distribution of these variables, 100 000 clinical trials were simulated for calculation of sample size required to reach sufficient power. For a treatment effect of 25% decrease in outcome variables, 50 patients were required in each arm using MSI compared to 93, 98, 120, 141, and 143 for MI size alone, hsTnT (area under the curve [ AUC ] and peak), and CKMB ( AUC and peak) in order to reach a power of 90%. If average CMR scan day between treatment and control arms differed by 1 day, sample size needs to be increased by 54% (77 vs 50) to avoid scan day bias masking a treatment effect of 25%. Conclusion Sample size in cardioprotection trials can be reduced 46% to 65% without compromising statistical power when using MSI by CMR as an outcome variable instead of MI size alone or biochemical markers. It is essential to ensure lack of bias in scan day between treatment and control arms to avoid compromising statistical power.

The laws of fluid dynamics govern vortex ring formation and precede cardiac development by billions of years, suggesting that diastolic vortex ring formation is instrumental in defining the shape of the heart. Using novel and validated magnetic resonance imaging measurements, we show that the healthy left ventricle moves in tandem with the expanding vortex ring, indicating that cardiac form and function is epigenetically optimized to accommodate vortex ring formation for volume pumping. Healthy hearts demonstrate a strong coupling between vortex and cardiac volumes (R2 = 0.83), but this optimized phenotype is lost in heart failure, suggesting restoration of normal vortex ring dynamics as a new and possibly important consideration for individualized heart failure treatment. Vortex ring volume was unrelated to early rapid filling (E-wave) velocity in patients and controls. Characteristics of vortex-wall interaction provide unique physiologic and mechanistic information about cardiac diastolic function that may be applied to guide the design and implantation of prosthetic valves and have potential clinical utility as therapeutic targets for tailored medicine or measures of cardiac health.

New automatic algorithm for segmentation of myocardial scar in both inversion recovery and phase sensitive inversion recovery late gadolinium enhancement: validation against TTC and in multi-center, multi-vendor patient data Jane Tufvesson, Robert Jablonowski, Henrik Engblom, Marcus Carlsson, Anthony H Aletras, Pavel Hoffmann, Alexis Jacquier, Frank Kober, Bernhard Metzler, David Erlinge, Dan Atar, Hakan Arheden, Einar Heiberg

The kinetic energy (KE) of intracardiac blood may play an important role in cardiac function. The aims of the present study were to 1) quantify and investigate the determinants of KE, 2) compare the KE expenditure of intracardiac blood between athletes and control subjects, and 3) quantify the amount of KE inside and outside the diastolic vortex. Fourteen athletes and fourteen volunteers underwent cardiac MRI, including four-dimensional phase-contrast sequences. KE was quantified in four chambers, and energy expenditure was calculated by determining the mean KE/cardiac index. Left ventricular (LV) mass was an independent predictor of diastolic LVKE ( R2= 0.66, P < 0.001), whereas right ventricular (RV) end-diastolic volume was important for diastolic RVKE ( R2= 0.76, P < 0.001). The mean KE/cardiac index did not differ between groups (control subjects: 0.53 ± 0.14 mJ·l−1·min·m2and athletes: 0.56 ± 0.21 mJ·l−1·min·m2, P = 0.98). Mean LV diastolic vortex KE made up 70 ± 1% and 73 ± 2% of total LV diastolic KE in athletes and control subjects ( P = 0.18). In conclusion, the characteristics of the LV as a pressure pump and the RV as a volume pump are demonstrated as an association between LVKE and LV mass and between RVKE and end-diastolic volume. This also suggests different filling mechanisms where the LV is dependent on diastolic suction, whereas the RV fills with a basal movement of the atrioventricular plane over “stationary” blood. Both groups had similar energy expenditure for intracardiac blood flow, indicating similar pumping efficiency, likely explained by the lower heart rate that cancels the higher KE per heart beat in athletes. The majority of LVKE is found within the LV diastolic vortex, in contrast to earlier findings.

Background T1 mapping is widely used today in CMR, however, it underestimates true T1 values and its measurement error is influenced by several acquisition parameters. The purpose of this study was the extraction of accurate T1 data through the utilization of comprehensive, parallel Simulations for QUAntifying RElaxation Magnetic Resonance constants (SQUAREMR) of the MOLLI pulse sequence on a large population of spins with physiologically relevant tissue relaxation constants. Methods A CMR protocol consisting of different MOLLI schemes was performed on phantoms and healthy human volunteers. For every MOLLI experiment, the identical pulse sequence was simulated for a large range of physiological combinations of relaxation constants, resulting in a database of all possible outcomes. The unknown relaxation constants were then determined by finding the simulated signals in the database that produced the least squared difference to the measured signal intensities. Results SQUAREMR demonstrated improvement of accuracy in phantom studies and consistent mean T1 values and consistent variance across the different MOLLI schemes in humans. This was true even for tissues with long T1s and MOLLI schemes with no pause between modified-Look-Locker experiments. Conclusions SQUAREMR enables quantification of T1 data obtained by existing clinical pulse sequences. SQUAREMR allows for correction of quantitative CMR data that have already been acquired whereas it is expected that SQUAREMR may improve data consistency and advance quantitative MR across imaging centers, vendors and experimental configurations. While this study is focused on a MOLLI-based T1-mapping technique, it could however be extended in other types of quantitative MRI throughout the body.

Background Measurement of intracardiac kinetic energy (KE) provides new insights into cardiac hemodynamics and may improve assessment and understanding of heart failure. We therefore aimed to investigate left ventricular (LV) KE time curves in patients with heart failure and in controls. Methods Patients with heart failure (n = 29, NYHA class I-IV) and controls (n = 12) underwent cardiovascular magnetic resonance (CMR) including 4D flow. The vortex-ring boundary was computed using Lagrangian coherent structures. The LV endocardium and vortex-ring were manually delineated and KE was calculated as ½mv2 of the blood within the whole LV and the vortex ring, respectively. Results The systolic average KE was higher in patients compared to controls (2.2 ± 1.4 mJ vs 1.6 ± 0.6 mJ, p = 0.048), but lower when indexing to EDV (6.3 ± 2.2 μJ/ml vs 8.0 ± 2.1 μJ/ml, p = 0.025). No difference was seen in diastolic average KE (3.2 ± 2.3 mJ vs 2.0 ± 0.8 mJ, p = 0.13) even when indexing to EDV (9.0 ± 4.4 μJ/ml vs 10.2 ± 3.3 μJ/ml, p = 0.41). In patients, a smaller fraction of diastolic average KE was observed inside the vortex ring compared to controls (72 ± 6 % vs 54 ± 9 %, p

Background: Myocardial perfusion single-photon emission computed tomography (MPS) can be used to assess myocardium at risk in occlusive coronary ischaemia. The aim was to develop a method to quantify myocardium at risk as perfusion defect size on ex vivo MPS using co-registration and fusion with ex vivo magnetic resonance imaging (MRI). Methods: Pigs (n = 19) were injected 99mTc-tetrofosmin prior to concluding 40 min of coronary artery occlusion, followed by reperfusion and MRI contrast injection. The excised heart was imaged with T1-weighted MRI and MPS, and images were co-registered using freely available software (Segment v1.8, http://segment.heiberg.se). The left ventricle was semi-automatically delineated in MRI and copied to MPS. The threshold for a MPS perfusion defect was defined as the mean counts in the MPS image at the MRI-determined border between remote myocardium and air. The threshold was measured using count maxima set to the 100th-95th percentile of counts within the myocardium. The count maximum that gave the lowest threshold variability (SD) was considered the most robust. Results: A count maximum using the 100th percentile yielded a threshold of (mean ± SD) 55 ± 6·2%. This method showed the lowest SD compared to 99th-95th percentile count maxima (6·6-7·2%). Conclusions: We describe a method for objective quantification of myocardium at risk as perfusion defect size on MPS using knowledge of the anatomy of the myocardium from co-registered MRI. This enables simultaneous quantification of myocardium at risk by MPS and infarct size by MRI for the evaluation of treatments for myocardial infarction. (Less)

Aim Spatial evolutionary and ecological vicariance analysis (SEEVA) is a simple analytical method that evaluates environmental or ecological divergence associated with evolutionary splits. It integrates evolutionary hypotheses, phylogenetic data, and spatial, temporal, environmental and geographical information to elucidate patterns. Using a phylogeny of Prepusa Mart. and Senaea Taub. (Angiospermae: Gentianaceae), SEEVA is used to describe the radiation and ecological patterns of this basal gentian group across south-eastern Brazil. Location Latin America, global. Methods Environmental data for 151 geolocated botanical collections, associated with specimens from seven species, were compiled with ARCGIS, and were matched with geolocated base layers of eight climatological variables, as well as one each of geological, soil type, elevational and vegetation variables. Sister groups were defined on the basis of the six nested nodes that defined the phylogenetic tree of these two genera. A (0, 1)-scaled divergence index (D) was defined and tested for each of 12 environmental and for each of the six phylogenetic nodes, by means of contingency analyses. We contrast divergence indices of nested clades, allopatric and sympatric sister clades. Results The level of ecological divergence between sister clades/species, defined in terms of D measures, was substantial for five of six nodes, with 21 of 72 environmental comparisons having D > 0.75. Soil types and geological age of bedrock were strongly divergent only for basal nodes in the phylogeny, by contrast with temperature and precipitation, which exhibited strong divergence at all nodes. There has been strong divergence and progressive occupation of wetter and colder habitats throughout the history of Prepusa. Nodes separating allopatric sister clades exhibited larger niche divergence than did those separating sympatric sister clades. Main conclusions SEEVA provides a multi-source, direct analysis method for correlating field collections, phylogenetic hypotheses, species distributions and georeferenced environmental data. Using SEEVA, it was possible to quantify and test the divergence between sister lineages, illustrating both niche conservatism and ecological specialization. SEEVA permits elucidation of historical and ecological vicariance for evolutionary lineages, and is amenable to wide application, taxonomically, geographically and ecologically.

Anteroseptal myocardial infarction (MI) is traditionally defined on the electrocardiogram (ECG) by ST elevations (STE) in leads V1-V3, with or without involvement of lead V4. While existing pedagogy depicts such MIs as affecting the basal anteroseptal myocardial segment, there are reports that the

ST changes in leads V4-V6 have been associated with more extensive coronary artery disease and worse outcomes in patients with inferior ST elevation myocardial infarction (iSTEMI). Correlation of electrocardiographic (ECG) findings to myocardial injury, assessed by cardiac magnetic resonance (CMR)

The pains Macrocarpaea (Griseb.) Gilg (Gentianaceae. Helieae) is among the largest woody genera of tropical gentians, with most of its species occurring in the wet mountainous forest., of the Andes. Phylogenetic and dispersal-vicariance analyses (DIVA) of 57 of the 105 currently recognized species in the genus. Using two data sets front nuclear DNA (ITS and 5S-NTS sequences) and morphology. show it single origin of the Andean species front all ancestral distribution that includes southeastern Brazil. Within the Andes. species divide into two major clades: (1) northern species front the cordilleras of northern Ecuador, Colombia. and Venezuela; and (2) southern species of the Andean Amotape-Huancabamba Zone in Ecuador and Peru as well as the Andes of central and southern Peru and Bolivia. The Amotape-Huancabamba zone is supported as the ancestral area for Macrocarpaea within the Andes. There are repeated speciation patterns within the Andes, and three Mesoamerican species derive front the northern clade, as is the single sampled species front the Guayana Shield. The position of the subclade of the three Caribbean Species is less certain. but it currently nests among Andean species. An Atlantic coastal Brazilian clade is placed its sister group to all other Macrocarpaea, providing further support for all ancestral refuge in southeastern Brazil for the Helieae. The biogeographic analysis showed that local speciation is more common than long-distance dispersal, and allopatric speciation is more common than sympatric speciation. Using detailed, georeferenced herbarium collection data. patterns in environmental characteristics between clades and sister species were analyzed with Spatial Evolutionary and Ecological Vicariance, Analysis (SEEVA), utilizing geographic information system (GIS) and statistical methods. Sister clades and taxa were evaluated for statistical significance in variables such as annual rainfall and temperature, elevation, temperature and rainfall seasonality, geological bedrock age, and soil type to evaluate ecological vicariance between sister group. The results indicate that there are no general patterns for each variable, but that there are significant divergences in ecological niches between both larger sister groups and sister species, and ecological niche conservation was also observed when subsequent nodes in the phylogeny were compared.

OBJECTIVES: Our goal was to validate myocardium at risk on T2-weighted short tau inversion recovery (T2-STIR) cardiac magnetic resonance (CMR) over time, compared with that seen with perfusion single-photon emission computed tomography (SPECT) in patients with ST-segment elevation myocardial infarction, and to assess the amount of salvaged myocardium after 1 week. BACKGROUND: To assess reperfusion therapy, it is necessary to determine how much myocardium is salvaged by measuring the final infarct size in relation to the initial myocardium at risk of the left ventricle (LV). METHODS: Sixteen patients with first-time ST-segment elevation myocardial infarction received (99m)Tc tetrofosmin before primary percutaneous coronary intervention. SPECT was performed within 4 h and T2-STIR CMR within 1 day, 1 week, 6 weeks, and 6 months. At 1 week, patients were injected with a gadolinium-based contrast agent for quantification of infarct size. RESULTS: Myocardium at risk at occlusion on SPECT was 33 +/- 10% of the LV. Myocardium at risk on T2-STIR did not differ from SPECT, at day 1 (29 +/- 7%, p = 0.49) or week 1 (31 +/- 6%, p = 0.16) but declined at week 6 (10 +/- 12%, p = 0.0096 vs. 1 week) and month 6 (4 +/- 11%, p = 0.0013 vs. 1 week). There was a correlation between myocardium at risk demonstrated by T2-STIR at week 1 and myocardium at risk by SPECT (r(2) = 0.70, p < 0.001), and the difference between the methods on Bland-Altman analysis was not significant (-2.3 +/- 5.7%, p = 0.16). Both modalities identified myocardium at risk in the same perfusion territory and in concordance with angiography. Final infarct size was 8 +/- 7%, and salvage was 75 +/- 19% of myocardium at risk. CONCLUSIONS: This study demonstrates that T2-STIR performed up to 1 week after reperfusion can accurately determine myocardium at risk as it was before opening of the occluded artery. CMR can also quantify salvaged myocardium as myocardium at risk minus final infarct size.

This study describes and validates a new method for automatic segmentation of left ventricular mass (LVM) in myocardial perfusion SPECT (MPS) images. This is important for estimating the size of a perfusion defect as percentage of the left ventricle. METHODS: A total of 101 patients with known or suspected coronary artery disease underwent both rest and stress MPS and MRI. A new automated algorithm was trained in 20 patients (40 MPS studies) and tested in 81 patients (162 MPS studies). The algorithm, which segmented the left ventricle in the MPS images, is based on Dijkstra's algorithm and finds an optimal mid-mural line through the left ventricular wall. From this line, the endocardium and epicardium are identified on the basis of an individually estimated wall thickness and signal intensity. The algorithm was validated by comparing LVM in both stress and rest MPS, with LVM of the manually segmented left ventricle from MRI as the reference standard. For comparison, LVM was quantified using the software quantitative perfusion SPECT (QPS). RESULTS: The mean difference +/- SD in LVM between MPS and MRI was lower for the new method (6% +/- 15% LVM) than for QPS (18% +/- 19% LVM) for both mean difference (P < 0.001) and SD (P = 0.015). Linear regression analysis of LVM, comparing MPS and MRI, yielded R(2) = 0.83 using the new method and R(2) = 0.80 using QPS. Interstudy variability, measured as the coefficient of variance between rest MPS and stress MPS, was 6% for both the new method and QPS. Both the new algorithm and QPS systematically overestimated LVM in hearts with thin myocardium and underestimated LVM in hearts with thick myocardium. CONCLUSION: The new segmentation algorithm quantifies LVM with a significantly lower bias and variability than does the commercially available QPS software, when compared to manually segmented LVM by MRI. This makes the new algorithm an attractive method to use for estimating the size of the perfusion defect when expressing it as percentage of the left ventricle. This study shows that inaccurate estimation of wall thickness is the main source of error in automatic segmentation. (Less)

Historically, Q-wave myocardial infarction (MI) has been equated with transmural MI. This association have, however, recently been rejected. The endocardial extent of MI is another potential determinant of pathological Q waves, since the first part of the QRS complex where the Q wave appears reflects depolarization of subendocardial myocardium. Therefore, the aim of the present study was to test the hypothesis that endocardial extent of MI is more predictive of pathological Q waves than is MI transmurality and to investigate the relationship between QRS scoring of the ECG and MI characteristics. Twenty-nine patients with reperfused first-time MI were prospectively enrolled. One week after admission, delayed contrast-enhanced magnetic resonance imaging (DE-MRI) was performed and 12-lead ECG was recorded. Size, transmurality and endocardial extent of MI were assessed by DE-MRI. Q waves were identified with Minnesota coding and electrocardiographic MI size was estimated by QRS scoring of the ECG. There was a significant difference between patients with and without Q waves with regard to MI size (P = 0.03) and endocardial extent of MI (P = 0.01), but not to mean and maximum MI transmurality (P = 0.09 and P = 0.14). Endocardial extent was the only independent predictor of pathological Q waves. Endocardial extent of MI was most strongly correlated to QRS score (r = 0.86, P < 0.001) of the MI variables tested. The endocardial extent of reperfused first-time acute MI is more predictive of pathological Q waves than is MI transmurality. (Less)

To present and validate a new method for 4D flow quantification of vortex-ring mixing during early, rapid filling of the left ventricle (LV) as a potential index of diastolic dysfunction and heart failure.4D flow mixing measurements were validated using planar laser-induced fluorescence (PLIF) in a phantom setup. Controls (n = 23) and heart failure patients (n = 23) were studied using 4D flow at 1.5T (26 subjects) or 3T (20 subjects) to determine vortex volume (VV) and inflowing volume (VVinflow ). The volume mixed into the vortex-ring was quantified as VVmix-in = VV-VVinflow . The mixing ratio was defined as MXR = VVmix-in /VV. Furthermore, we quantified the fraction of the end-systolic volume (ESV) mixed into the vortex-ring (VVmix-in /ESV) and the fraction of the LV volume at diastasis (DV) occupied by the vortex-ring (VV/DV).PLIF validation of MXR showed fair agreement (R(2) = 0.45, mean ± SD 1 ± 6%). MXR was higher in patients compared to controls (28 ± 11% vs. 16 ± 10%, P0.001), while VVmix-in /ESV and VV/DV were lower in patients (10 ± 6% vs. 18 ± 12%, P0.01 and 25 ± 8% vs. 50 ± 6%, P0.0001).Vortex-ring mixing can be quantified using 4D flow. The differences in mixing parameters observed between controls and patients motivate further investigation as indices of diastolic dysfunction. J. Magn. Reson. Imaging 2016;43:1386-1397.

Background Accurate quantification of iron load is of importance in tailoring the therapy for patients with iron load disease. Magnetic resonance (MR) imaging is commonly used to assess iron load in different organs by calculating the T2* value. Estimation of precision and uncertainty of the obtained T2* value may be useful for determining changes in iron load between follow-up scans and for titration of treatment. Therefore, the purpose of this study was to develop and validate a new T2* analysis method, providing certainty estimates for quantification of iron load in heart and liver. Methods The proposed method is ar egion of interest (ROI)based algorithm which changes curve-fitting procedure based on the results from an initial T2* estimate using a 3-parameter, noise-corrected model. The certainty estimate, presented as the T2* value confidence interval, is derived from multiple sub-regions within the selected ROI. Except for ROI delineation, the proposed method does not require any user interaction. Phantom imaging was performed on a 1.5T system, with two clinically available multi-echo gradient-recalled echo sequences for cardiac and liver imaging. Phantoms were constructed to cover the clinically important range of T2*. A T2* single-echo gradient-echo sequence with TR set to 6 × T1 and a 50° flip angle was used as reference standard. Computer simulations were performed to assess accuracy and precision from 2 000 repetitions at SNR=15. Inter- and intra-observer variability was obtained in patients (n=22) by one experienced and one inexperienced observer.

Background The development of treatments to limit myocardial injury in patients with acute STEMI is dependent on methods that accurately determine the amount of mycoardium at risk (MaR). Both T2-weighted imaging and contrast enhanced SSFP (CE-SSFP) have been validated against SPECT and can determine the MaR by CMR one week after an infarct. CE-SSFP has recently been used in two multi-center studies 1,2 . An automatic algorithm for quantification of MaR from T2-weighted images has previously been described but not been tested in CE-SSFP. The aim of this study was to further develop and validate this automatic method for CE-SSFP. Methods

Background Infarct size is increasingly used as an efficacy endpoint in randomized trials comparing acute myocardial infarct (AMI) therapies. Infarct size, depicted by delayedenhancement-CMR, is quantified using manual planimetry (MANUAL), visual scoring (VISUAL), or automated techniques using signal-intensity thresholding to define infarct borders (AUTO). Although AUTO is considered the most reproducible, prior studies did not account for the subjective determination of endocardial/epicardial borders, which all methods require. For MANUAL and VISUAL, prior studies have not explicitly defined how to treat intermediate signal-intensities due to partial volume. We wanted to assess sources of variability among 6 methods in quantification of AMI size, and illustrate the significance of these findings on sample size calculations for clinical trials.

Background Cardiac magnetic resonance imaging (CMR) can be used to determine both myocardial infarct (MI) size and myocardium at risk (MaR), enabling assessment of myocardial salvage index (MSI). MI size as assessed by hyperenhancement on late gadolinium enhancement (LGE) has been shown to decrease approximately 25% during the first week after infarction. The aim of this study was to determine to what extent assessment of MSI and a narrow inclusion window affect the number of patients needed to reach sufficient statistical power in a clinical CMR cardioprotection trial. Methods Control subjects (n=91) from the recent CHILL-MI 1 and MITOCARE 2 cardioprotection trials, examined by CMR 2-6 days after acute reperfusion therapy, were used to assess the difference in sample size required to reach sufficient statistical power when using MI size alone compared to MSI as outcome variable. In addition, 22 patients undergoing CMR at day 1 and 7 after acute reperfused infarction from a previous follow-up study 3 were included to assess to what extent sample size is affected by the decrease in hyperenhancement seen during the first week after infarction. The variability of MI size by LGE, MaR by contrast-enhanced SSFP and MSI was used to simulate 100.000 clinical trials for different assumed treatment effects to determine the number of patients needed to reach sufficient statistical power. Results

Background Arterial stiffness is one of the most potent prognostic factors of cardiovascular morbidity and mortality. Its surrogate parameter, pulse wave velocity (PWV), is most commonly assessed by carotid-femoral applanation tonometry (AT). Limited availability of the AT equipment limits its application in clinical practice. Phase contrast cardiac magnetic resonance (CMR) offers insight in arterial stiffness at no extra cost, without significant protocol extension. As CMR accessibility increases, validated post-processing tools for CMRderived PWV measurement are needed. The aim of the study was to provide a validated, freely available tool to measure PWV using a routine CMR protocol.

Background The heterogeneous peri-infarction zone surrounding the core infarct with cardiac magnetic resonance imaging (CMR) late gadolinium enhancement (LGE) has been linked to all-cause mortality in patients with coronary artery disease. Previously, the heterogeneity of fibrotic areas has been analyzed by threshold algorithms. We hypothesized that the heterogeneous peri-infarction zone is related to appropriate ICD-therapy in ischemic cardiomyopathy patients. Therefore, the purpose of this study was to investigate if 1) infarct heterogeneity can predict appropriate ICD-therapy and 2) evaluate which analysis method best depicts and quantifies the periinfarction zone.

AIM: The MITOCARE study evaluated the efficacy and safety of TRO40303 for the reduction of reperfusion injury in patients undergoing revascularization for ST-elevation myocardial infarction (STEMI).METHODS: Patients presenting with STEMI within 6 h of the onset of pain randomly received TRO40303 (n = 83) or placebo (n = 80) via i.v. bolus injection prior to balloon inflation during primary percutaneous coronary intervention in a double-blind manner. The primary endpoint was infarct size expressed as area under the curve (AUC) for creatine kinase (CK) and for troponin I (TnI) over 3 days. Secondary endpoints included measures of infarct size using cardiac magnetic resonance (CMR) and safety outcomes.RESULTS: The median pain-to-balloon time was 180 min for both groups, and the median (mean) door-to-balloon time was 60 (38) min for all sites. Infarct size, as measured by CK and TnI AUCs at 3 days, was not significantly different between treatment groups. There were no significant differences in the CMR-assessed myocardial salvage index (1-infarct size/myocardium at risk) (mean 52 vs. 58% with placebo, P = 0.1000), mean CMR-assessed infarct size (21.9 g vs. 20.0 g, or 17 vs. 15% of LV-mass) or left ventricular ejection fraction (LVEF) (46 vs. 48%), or in the mean 30-day echocardiographic LVEF (51.5 vs. 52.2%) between TRO40303 and placebo. A greater number of adjudicated safety events occurred in the TRO40303 group for unexplained reasons.CONCLUSION: This study in STEMI patients treated with contemporary mechanical revascularization principles did not show any effect of TRO40303 in limiting reperfusion injury of the ischaemic myocardium.

The aim of this study was to evaluate the accuracy of maximum velocity measurements using volumetric phase-contrast imaging with spiral readouts in a stenotic flow phantom. In a phantom model, maximum velocity, flow, pressure gradient, and streamline visualizations were evaluated using volumetric phase-contrast magnetic resonance imaging (MRI) with velocity encoding in one (extending on current clinical practice) and three directions (for characterization of the flow field) using spiral readouts. Results of maximum velocity and pressure drop were compared to computational fluid dynamics (CFD) simulations, as well as corresponding low-echo-time (TE) Cartesian data. Flow was compared to 2D through-plane phase contrast (PC) upstream from the restriction. Results obtained with 3D through-plane PC as well as 4D PC at shortest TE using a spiral readout showed excellent agreements with the maximum velocity values obtained with CFD (

In order to determine the cardioprotective efficacy of acute reperfusion therapy, assessed as myocardial salvage, in patients with acute coronary occlusion, the final myocardial infarct (MI) size needs to be related to the amount of ischemic myocardium during coronary occlusion, referred to as the myocardium at risk (MaR). There are currently several imaging approaches available for quantification of both MI size and MaR in vivo of which some have been validated both in pre-clinical and clinical settings. These methods often involve the use of either myocardial perfusion SPECT or cardiac magnetic resonance (CMR). These imaging methods could potentially be used to further develop and validate ECG methods for determination of MI size and MaR. Therefore, the aim of the present review is to give an overview of myocardial perfusion SPECT and CMR methods available for assessment of myocardial salvage by determination of MI size and MaR.

Septal systolic motion is towards the left ventricle (LV) in healthy hearts. Patients with pulmonary regurgitation (PR) and right ventricular (RV) volume overload have systolic septal motion toward the RV. This may affect the longitudinal contribution from atrioventricular plane displacement (AVPD) and septal and lateral contribution to stroke volume (SV). The study aimed to quantify these contributions to SV in patients with PR. Cardiac magnetic resonance imaging was used for assessment of cardiac volumes. Patients ( n = 30; age 9–59 yr) with PR due to surgically corrected tetralogy of Fallot and 54 healthy controls (age 10–66 yr) were studied. Longitudinal contribution to RVSV was 47 ± 2% (means ± SE) in patients with PR and 79 ± 1% in controls ( P < 0.001). Lateral contribution to RVSV and LVSV was 40 ± 1 and 62 ± 2% in patients and 31 ± 1 and 36 ± 1% in controls ( P < 0.001 for both). Septal motion contributed to RVSV by 8 ± 1% in patients and by 7 ± 1% to LVSV in controls ( P < 0.001). PR patients have decreased longitudinal contribution to RVSV and increased lateral pumping, resulting in larger outer volume changes and septal motion towards the RV. The changes in RV pumping physiology may be explained by RV remodeling resulting in lower systolic inflow of blood into the right atrium in relation to SV. This avoids the development of pendulum volume between the caval veins and right atrium, which would occur in PR patients if longitudinal contribution to SV was preserved. Decreased AVPD suggests that tricuspid annular excursion, a marker of RV function, is less valid in these patients.

Myocardial perfusion SPECT (MPS) is one of the frequently used methods for quantification of perfusion defects in patients with known or suspected coronary artery disease. This article describes open access software for automated quantification in MPS of stress-induced ischemia and infarction and provides phantom and in vivo validation. A total of 492 patients with known or suspected coronary artery disease underwent both stress and rest MPS. The proposed perfusion analysis algorithm (Segment) was trained in 140 patients and validated in the remaining 352 patients using visual scoring in MPS by an expert reader as reference standard. Furthermore, validation was performed with simulated perfusion defects in an anthropomorphic computer model. Total perfusion deficit (TPD, range 0-100), including both extent and severity of the perfusion defect, was used as the global measurement of the perfusion defects. Mean bias ± SD between TPD by Segment and the simulated TPD was 3.6 ± 3.8 (R 2 = 0.92). Mean bias ± SD between TPD by Segment and the visual scoring in the patients was 1.2 ± 2.9 (R 2 = 0.64) for stress-induced ischemia and −0.3 ± 3.1 (R 2 = 0.86) for infarction. The proposed algorithm can detect and quantify perfusion defects in MPS with good agreement to expert readers and to simulated values in a computer phantom.

Background Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is considered the gold standard for quantification of myocardial infarction in vivo. Myocardium with increased fractional distribution volume (fDV) due to acute necrosis or chronic scar exhibit hyperenhancement relative to viable myocardium when using a gadoliniumbased extracellular contrast agent. Previous studies have

Background Cardiovascular-MR (CMR) is the gold standard for quantifying myocardial infarction using late gadolinium enhancement (LGE) technique. Both 2D- and 3D-LGE-sequences are used in clinical practise and in clinical and experimental studies for infarct quantification. Therefore the aim of this study was to investigate if image acquisitions with 2D- and 3D-LGE show the same infarct size in patients and ex vivo. Methods Twenty-six patients with previous myocardial infarction who underwent a CMR scan were included. Images were acquired 10-20 minutes after an injection of 0.2 mmol/kg gadolinium-based contrast agent. Two LGE-sequences, 3D-inversion recovery (IR) and 2D-phase-sensitive (PS) IR, were used in all patients to quantify infarction size. Furthermore, six pigs with reperfused infarction in the left anterior descending artery (40 minutes occlusion and 4 hours of reperfusion) were scanned with 2D- and 3D-LGE ex vivo. A high resolution T1-sequence was used as reference for the infarct quantification ex vivo. Spearman’s rank-order correlation, Wilcoxon matched pairs test and bias according to Bland-Altman was used for comparison of infarct size with different LGE-sequences. Results There was no significant difference between the 2D- and 3D-LGE sequence in left ventricular mass (LVM) (2D: 115 ± 25 g; 3D: 117 ± 24 g: p = 0.35). Infarct size in vivo using 2D- and 3D-LGE showed high correlation and low bias for both LGE-sequences both in absolute volume of infarct (r = 0.97, bias 0.47 ± 2.1 ml) and infarct size as part of LVM (r = 0.94, bias 0.16 ± 2.0%). The 2D- and 3D-LGE-sequences ex vivo correlated well (r = 0.93, bias 0.67 ± 2.4%) for infarct size as part of the LVM. The IR LGE-sequences overestimated infarct size as part of the LVM ex vivo compared to the high resolution T1-sequence (bias 6.7 ± 3.0%, 7.3 ± 2.7% for 2D-PSIR and 3D-IR respectively, p Conclusions Infarct quantification with 2D- and 3D-LGE gives similar results in vivo with a very low bias. IR LGE-sequences optimized for in vivo use yield an overestimation of infarct size when used ex vivo.

Kinetic energy (KE) of atrial blood has been postulated as a possible contributor to ventricular filling. Therefore, we aimed to quantify the left (LA) and right (RA) atrial blood KE using cardiac magnetic resonance (CMR). Fifteen healthy volunteers underwent CMR at 3 T, including a four-dimensional phase-contrast flow sequence. Mean LA KE was lower than RA KE (1.1 ± 0.1 vs. 1.7 ± 0.1 mJ, P < 0.01). Three KE peaks were seen in both atria: one in ventricular systole, one during early ventricular diastole, and one during atrial contraction. The systolic LA peak was significantly smaller than the RA peak ( P < 0.001), and the early diastolic LA peak was larger than the RA peak ( P < 0.05). Rotational flow contained 46 ± 7% of total KE and conserved energy better than nonrotational flow did. The KE increase in early diastole was higher in the LA ( P < 0.001). Systolic KE correlated with the combination of atrial volume and systolic velocity of the atrioventricular plane displacement ( r2 = 0.57 for LA and r2 = 0.64 for RA). Early diastolic KE of the LA correlated with left ventricle (LV) mass ( r2 = 0.28), however, no such correlation was found in the right heart. This suggests that LA KE increases during early ventricular diastole due to LV elastic recoil, indicating that LV filling is dependent on diastolic suction. Right ventricle (RV) relaxation does not seem to contribute to atrial KE. Instead, RA KE generated during ventricular systole may be conserved in a hydraulic “flywheel” and transferred to the RV through helical flow, which may contribute to RV filling.

Background Infarct size measurements with delayed-enhancement cardiovascular magnetic resonance (DE-CMR) are being used as surrogate endpoints in acute myocardial infarction (AMI) trials comparing therapeutic strategies. Semiautomated techniques using signal intensity thresholding are thought to be more reproducible than manual planimetry to define AMI borders. For both methods, endo-/ epicardial borders are determined by manual planimetry, which was not considered in prior reproducibility studies. Visual scoring of AMI size based on a standard 17-segment, 5-point score is faster and does not require planimetry of endo-/epicardial borders. We compared the reproducibility of visual scoring, manual planimetry and semiautomated techniques. Methods Thirty patients with first AMI (58+/-11 years, 80% male), who underwent DE-CMR within 7 days after first elevated troponin test were enrolled. All scans were evaluated independently at each participating CMR core lab with at least three months temporal separation between analyses in the following manner: A) manual planimetry of the endo-/epicardial contours and infarct borders (MP), B) manual planimetry of endo-/epicardial contours, AMI size determined using a semiautomated technique with voxel weighting based on signal intensity, without user input (AUTO), C) same as B with user correction for no-reflow, artifact, etc. (AUTOcorrected), and D) visual scoring using a 17-segment, 5-point score (VISUAL). This comparison is based on a total of 30 measurements by three core-labs in four different manners for a total of 360 AMI size measurements. Interobserver reproducibility was assessed using a) standard error of difference from mean (SED), and b) 1-intraclass-correlation coefficient (ICC). A SED

Background Automatic segmentation of the left ventricle (LV) is desirable to assess the cardiac parameters end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) and left ventricular mass (LVM) since manual segmentation is time consuming and observer dependent. A physiologically correct segmentation of the left ventricle requires careful consideration of the long axis displacement and the LV outflow tract which makes the myocardium non-circumferential in the basal slices. To detect the long axis displacement a constraint could be used to keep the LVM fairly constant over the cardiac cycle. However, in order to use this constraint, the error of the segmentation has to be low regarding both endocardial and epicardial borders in the non-basal part of the LV. Therefore, the purpose of this study was to improve and validate an automatic algorithm for LV segmentation in the non-basal part of the LV, as a first step towards fully automatic segmentation.

Background Intracardiac blood flow is known to influence cardiac development through transduction of endothelial shear forces. Vortex rings inside the left ventricle constitute a possible “blueprint” for cardiogenesis, the hemodynamic determinant of final cardiac shape. However, the relationship between the vortex ring and endocardium has previously not been quantified, and the influence of the vortex ring dimensions on the shape of the heart has therefore not been considered. We hypothesized a dynamic coupling between the vortex ring and the healthy left ventricle throughout diastole, and uncoupling in the diseased heart (Fig. 1). Methods 16 healthy volunteers and 23 patients with heart failure (n = 12 ischemic, n = 11 non-ischemic dilated cardiomyopathy), underwent CMR examination at 1.5T (n = 27) or 3T (n = 8), including 4D flow. Vortex ring boundary was calculated using Lagrangian Coherent Structures (LCS) and CUDA parallel computing. Vortex ring and LV endocardium were manually delineated, and the average distance between the delineations was measured for all time points in diastole.

Background In theory, movement of the septum contributes to left ventricular stroke volume (LVSV) if the movement is toward the left ventricle (LV) in systole. If the septum movement is toward the right ventricle (RV), as in dyssynchrony, the septal contribution to LVSV decreases. In patients with increased volume load of the RV the septum may move towards the RV and contribute to right ventricular stroke volume RVSV) at the expense of LVSV. The amount of contribution to stroke volume from septal movement is not kown. The aim of the study was to quantify the percentage of the left ventricular stroke volume, that is derived by the septal movement during systole, in healthy volunteers and patients with volume or pressure load of the RV. Methods Cardiac MRI was used for three-dimensional assessment of cardiac volumes and septal movement. Four groups were examined; healthy subjects (n=29), athletes with high aerobic capacity (n=12), patients with an increased right ventricular volume load from moderate or severe pulmonary insufficiency (PI) in surgically corrected tetralogy of Fallot (n=20) and surgically corrected pulmonary stenosis (PS) (n=2) and patients with an increased right ventricular pressure overload secondary to pulmonary hypertension (n=11). LVSV was calculated by delineation of the endocardium of the LV in diastole and systole. The border between the LV and RV, i.e. the epicardial contour of the septum was delineated in diastole and systole from the apex to the base. Thereby the three-dimensional volume, derived from septal movement, was quantified. Results Septal movement contributed to 8.7±0.7% of stroke volume in healthy subjects and 7.5±0.6% in athletes (p=ns). However, in patients with PI because of surgically corrected tetralogy of Fallot or PS, the septum contributes to right ventricular stroke volume by 14.1±1.7% (p

Treatment of acute ST-elevation myocardial infarction (STEMI) by reperfusion using percutaneous coronary intervention (PCI) or thrombolysis has provided clinical benefits; however, it also induces considerable cell death. This process is called reperfusion injury. The continuing high rates of mortality and heart failure after acute myocardial infarction (AMI) emphasize the need for improved strategies to limit reperfusion injury and improve clinical outcomes. The objective of this study is to assess safety and efficacy of TRO40303 in limiting reperfusion injury in patients treated for STEMI. TRO40303 targets the mitochondrial permeability transition pore, a promising target for the prevention of reperfusion injury. This multicenter, double-blind study will randomize patients with STEMI to TRO40303 or placebo administered just before balloon inflation or thromboaspiration during PCI. The primary outcome measure will be reduction in infarct size (assessed as plasma creatine kinase and troponin I area under the curve over 3 days). The main secondary endpoint will be infarct size normalized to the myocardium at risk (expressed by the myocardial salvage index assessed by cardiac magnetic resonance). The study is being financed under an EU-FP7 grant and conducted under the auspices of the MITOCARE research consortium, which includes experts from clinical and basic research centers, as well as commercial enterprises, throughout Europe. Results from this study will contribute to a better understanding of the complex pathophysiology underlying myocardial injury after STEMI. The present paper describes the rationale, design and the methods of the trial. Copyright (c) 2012 S. Karger AG, Basel (Less)

Recent studies suggest that vortex ring formation during left ventricular (LV) rapid filling is an optimized mechanism for blood transport, and that the volume of the vortex ring is an important measure. However, due to lack of quantitative methods, the volume of the vortex ring has not previously been studied. Lagrangian Coherent Structures (LCS) is a new flow analysis method, which enables in vivo quantification of vortex ring volume. Therefore, we aimed to investigate if vortex ring volume in the human LV can be reliably quantified using LCS and magnetic resonance velocity mapping (4D PC-MR). Flow velocities were measured using 4D PC-MR in 9 healthy volunteers and 4 patients with dilated ischemic cardiomyopathy. LV LCS were computed from flow velocities and manually delineated in all subjects. Vortex volume in the healthy volunteers was 51 ± 6% of the LV volume, and 21 ± 5% in the patients. Interobserver variability was -1 ± 13% and interstudy variability was -2 ± 12%. Compared to idealized flow experiments, the vortex rings showed additional complexity and asymmetry, related to endocardial trabeculation and papillary muscles. In conclusion, LCS and 4D PC-MR enables measurement of vortex ring volume during rapid filling of the LV.