Background-Magnetic resonance imaging (MRI) permits 3-dimensional (3D) cardiac imaging with high soft tissue contrast. X-ray fluoroscopy provides high-resolution, 2-dimensional (2D) projection imaging. We have developed real-time x-ray fused with MRI (XFM) to guide invasive procedures that combines the best features of both imaging modalities. We tested the accuracy of XFM using external fiducial markers to guide endomyocardial cell injections in infarcted swine hearts. Methods and Results-Endomyocardial injections of iron-labeled mesenchymal stromal cells admixed with tissue dyewere performed in previously infarcted hearts of 12 Yucatan miniswine (weight, 33 to 67 kg). Features from cardiac MRI were displayed combined with x-ray in real time to guide injections. During 130 injections, operators were provided with 3D surfaces of endocardium, epicardium, myocardial wall thickness (range, 2.6 to 17.7 mm), and infarct registered with live x-ray images to facilitate device navigation and choice of injection location. XFM-guided injections were compared with postinjection MRI and with necropsy specimens obtained 24 hours later. Visual inspection of the pattern of dye staining on 2,3,5-triphenyltetrazolium chloride-stained heart slices agreed (ϭ0.69) with XFM-derived injection locations mapped onto delayed hyperenhancement MRI and the susceptibility artifacts seen on the postinjection T2*-weighted gradient echo MRI. The distance between the predicted and actual injection locations in vivo was 3.2Ϯ2.6 mm (nϭ64), and 75% of injections were within 4.1 mm of the predicted location. Conclusions-Three-dimensional to two-dimensional registration of x-ray and MR images with the use of external fiducial markers accurately targets endomyocardial injection in a swine model of myocardial infarction.

Background-We have developed and validated a system for real-time X-ray fused with magnetic resonance imaging, MRI (XFM), to guide catheter procedures with high spatial precision. Our implementation overlays roadmaps-MRI-derived soft-tissue features of interest-onto conventional X-ray fluoroscopy. We report our initial clinical experience applying XFM, using external fiducial markers, electrocardiogram (ECG)-gating, and automated real-time correction for gantry and table movement.

X-ray images acquired on systems with image intensifiers (II) exhibit characteristic distortion which is due to both external and internal factors. The distortion is dependent on the orientation of the II, a fact particularly relevant to II's mounted on C arms which have several degrees of freedom of motion. Previous descriptions of distortion correction strategies have relied on a dense sampling of the C-arm orientation space, and as such have been limited mostly to a single arc of the primary angle, alpha. We present a new method which smooths the trajectories of the segmented vertices of the grid phantom as a function of a prior to solving the two-dimensional warping problem. It also shows that the same residual errors of distortion correction could be achieved without fitting the trajectories of the grid vertices, but instead applying the previously described global method of distortion correction, followed by directly smoothing the values of the polynomial coefficients as functions of the C-arm orientation parameters. When this technique was applied to a series of test images at arbitrary alpha, the root-mean-square (RMS) residual error was 0.22 pixels. The new method was extended to three degrees of freedom of the C-arm motion: the primary angle, alpha; the secondary angle, beta; and the source-to-intensifier distance, lambda. Only 75 images were used to characterize the distortion for the following ranges: alpha, +/- 45 degrees (Deltaalpha = 22.5 degrees); beta, +/- 36 degrees (Deltabeta = 18 degrees); lambda, 98-118 cm (Deltalambda = 10 cm). When evaluated on a series of test images acquired at arbitrary (alpha, beta, lambda), the RMS residual error was 0.33 pixels. This method is targeted at applications such as guidance of catheter-based interventions and treatment planning for brachytherapy, which require distortion-corrected images over a large range of C-arm orientations.

Objectives We hypothesize that X-ray fused with MRI (XFM) roadmaps might permit direct antegrade crossing and delivery of a VSD closure device and thereby reduce procedure time and radiation exposure. Background Percutaneous device closure of membranous ventricular septal defect (VSD) is cumbersome and time-consuming. The procedure requires crossing the defect retrograde, snaring and exteriorizing a guidewire to form an arteriovenous loop, then delivering antegrade a sheath and closure device. Methods MRI roadmaps of cardiac structures were obtained from miniature swine with spontaneous ventricular septal defect and registered with live X-ray using external fiducial markers. We compared antegrade XFM-guided VSD crossing with conventional retrograde X-ray guided crossing for repair. Results Antegrade XFM crossing was successful in all animals. Compared with retrograde X-ray, antegrade XFM was associated with shorter time to crossing (167 ± 103 seconds versus 284 ± 61 seconds; p = 0.025), shorter time to sheath delivery (71 ± 32 seconds versus 366 ± 145 seconds; p = 0.001), shorter fluoroscopy time (158 ± 95 seconds versus 390 ± 137s; p = 0.003), and reduced radiation dose-area product (2394 ± 1522 mG•m2 versus 4865 ± 1759 mG•m2; p = 0.016). Conclusions XFM facilitates antegrade access to membranous VSD from the right ventricle in swine. The simplified procedure is faster and reduces radiation exposure compared with the conventional retrograde approach.

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Wine differentiation is an important issue for the Chilean winemaking industry, especially for the Carménère variety, which was rediscovered in this country around 20 years ago. Authentication parameters are required for this wine due to its frequent confusion with Merlot. The concentration of anthocyanins, shikimic acid, and the principal flavonols found in wine allowed some varietal differentiation between Carménère and Merlot wines. Myricetin and quercetin are the most concentrated flavonols in wine in which they are present in free and conjugated forms. These compounds are responsible for important wine antioxidant properties.In the present work, using only the concentrations of free and conjugated quercetin and myricetin, differentiation between Carménère and Merlot varieties was better achieved. Flavonol profiles of wine produced in Chile were studied with HPLC-DAD-ESI-MSn . An overview of the concentration range of flavonols present in 248 Chilean red wines is presented, finding that the mean concentration of the sum of total myricetin and total quercetin were higher in Carménère (81.5 mgL ) wines. These mean levels were higher than the majority of the concentrations reported in the literature. The chemometric analysis shows that the ratio of total quercetin/total myricetin combined with the concentration of free myricetin allowed the varietal differentiation between Carménère and Merlot wines.

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