Right ventricular midwall surface motion and deformation using magnetic resonance tagging

1996 ◽  
Vol 271 (6) ◽  
pp. H2677-H2688 ◽  
Author(s):  
A. A. Young ◽  
Z. A. Fayad ◽  
L. Axel
Keyword(s):  
Magnetic Resonance ◽  
Right Ventricular ◽  
Mean Squared Error ◽  
Three Dimensional ◽  
Element Model ◽  
Right Ventricular Free Wall ◽  
Tissue Tagging ◽  
Magnetic Resonance Tagging ◽  
The Right

We describe a method for reconstructing the three-dimensional motion and deformation of the midwall surface of the right ventricular free wall (RVFW) using magnetic resonance tissue tagging. Tag points were defined where the tag stripes intersected the midwall contour and were tracked through systole in both short- and long-axis images. A finite-element model of the midwall surface of the RVFW was constructed to fit the midwall shape at end diastole. The model was then deformed to each subsequent frame by fitting the tag displacements and midwall contour locations. The method was applied to two human studies, a normal subject and a patient with right ventricular hypertrophy. The root mean squared error between model tag planes and tracked tag points was 0.70 mm for the normal heart (180 points) and 0.67 mm for the hypertrophic heart (52 points), both less than the image pixel size of approximately 1.0 mm. The differences in contraction patterns were visualized between the two studies. We conclude that this method allows accurate, noninvasive measurement of in vivo RVFW deformation.

scholarly journals Alteration within the Hippocampal Volume in Patients with LHON Disease—7 Tesla MRI Study

2020 ◽  
Vol 10 (1) ◽  
pp. 14
Author(s):  
Cezary Grochowski ◽  
Kamil Jonak ◽  
Marcin Maciejewski ◽  
Andrzej Stępniewski ◽  
Mansur Rahnama-Hezavah
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Molecular Layer ◽  
Three Dimensional ◽  
Hippocampal Volume ◽  
7 Tesla ◽  
Diagnostic Process ◽  
Resonance Imaging ◽  
The Right

Purpose: The aim of this study was to assess the volumetry of the hippocampus in the Leber’s hereditary optic neuropathy (LHON) of blind patients. Methods: A total of 25 patients with LHON were randomly included into the study from the national health database. A total of 15 patients were selected according to the inclusion criteria. The submillimeter segmentation of the hippocampus was based on three-dimensional spoiled gradient recalled acquisition in steady state (3D-SPGR) BRAVO 7T magnetic resonance imaging (MRI) protocol. Results: Statistical analysis revealed that compared to healthy controls (HC), LHON subjects had multiple significant differences only in the right hippocampus, including a significantly higher volume of hippocampal tail (p = 0.009), subiculum body (p = 0.018), CA1 body (p = 0.002), hippocampal fissure (p = 0.046), molecular layer hippocampus (HP) body (p = 0.014), CA3 body (p = 0.006), Granule Cell (GC) and Molecular Layer (ML) of the Dentate Gyrus (DG)–GC ML DG body (p = 0.003), CA4 body (p = 0.001), whole hippocampal body (p = 0.018), and the whole hippocampus volume (p = 0.023). Discussion: The ultra-high-field magnetic resonance imaging allowed hippocampus quality visualization and analysis, serving as a powerful in vivo diagnostic tool in the diagnostic process and LHON disease course assessment. The study confirmed previous reports regarding volumetry of hippocampus in blind individuals.

scholarly journals ECG-gated dynamic magnetic resonance imaging method for examination of the pig heart

2001 ◽  
Vol 49 (3) ◽  
pp. 275-284
Author(s):  
Zs. Petrási ◽  
R. Romvári ◽  
G. Bajzik ◽  
B. Fenyves ◽  
I. Repa ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Three Dimensional ◽  
Dynamic Magnetic Resonance Imaging ◽  
Imaging Method ◽  
Resonance Imaging ◽  
Dynamic Magnetic Resonance ◽  
Heart Cycle ◽  
The Right

A dynamic magnetic resonance imaging (MRI) method was developed for in vivo examination of the pig heart. Measurements were carried out on 15 meat-type pigs of different liveweight using a 1.5 T equipment. Inhalation anaesthesia was applied, then data acquisition was synchronised by ECG gating. Depending on the heart rate and heart size, in each case 8 to 10 slices and in each slice 8 to 14 phases were acquired prospectively according to one heart cycle. During the post-processing of the images the left and the right ventricular volumes were determined. The values measured at 106 kg liveweight are 2.5 times higher than those obtained at 22 kg, while the ejection fractions are equal. The calculated cardiac output values were 3.5 l (22 kg, 132 beats/min.), and 6.0 l (106 kg, 91 beats/min.), respectively. After measuring the wall thickness, the contraction values were also determined for the septum (70%), and for the anterior (61%), posterior (41%) and lateral (54%) walls of the left ventricle. Three-dimensional animated models of the ventricles were constructed. Based on the investigations performed, the preconditioning, the anaesthetic procedure, the specific details of ECG measurement and the correct MR imaging technique were worked out.

scholarly journals The vectorcardiogram and the main dromotropic disturbances

2020 ◽  
Vol 16 ◽  
Author(s):  
Andrés Ricardo Pérez-Riera ◽  
Raimundo Barbosa-Barros ◽  
Rodrigo Daminello-Raimundo ◽  
Luiz Carlos de Abreu ◽  
Kjell Nikus
Keyword(s):  
Differential Diagnosis ◽  
Right Ventricular ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Three Dimensional ◽  
Myocardial Infarctions ◽  
Right Ventricular Free Wall ◽  
Intraventricular Conduction ◽  
Conduction Disturbances ◽  
The Right ◽  
Ventricular Preexcitation

: Until the mid-1980s, it was believed that the vectorcardiogram (VCG) presented a greater specificity, sensitivity and accuracy in comparison to the 12-lead electrocardiogram (ECG), in the cardiology diagnosis. Currently, the VCG still is superior to the ECG in specific situations, such as in the evaluation of myocardial infarctions when associated with intraventricular conduction disturbances, in the identification and location of accessory pathways in ventricular preexcitation, in the differential diagnosis of patterns varying from normal of electrical axis deviation, in the evaluation of particular aspects of Brugada syndrome, Brugada phenocopies, concealed form of arrhythmogenic right ventricular cardiomyopathy and zonal or fascicular blocks of the right bundle branch on right ventricular free wall .VCG allows us to analyze the presence of left septal fascicular block more accurately than ECG and in the diagnosis of the interatrial blocks and severity of some chambers enlargements. The three-dimensional spatial orientation of both the atrial and the ventricular activity provides a far more complete observation tool than the linear ECG. We believe that the ECG/VCG binomial simultaneously obtained by the technique called electro-vectorcardiography (ECG/VCG) brought a significant gain for the differential diagnosis of several pathologies. Finally, in the field of education and research, VCG provided a better and more rational tridimensional insight into the electrical phenomena that occurs spatially, and represented an important impact on the progress of electrocardiography.

scholarly journals An In Vivo 3D Micro-CT Evaluation of Tooth Movement After the Application of Different Force Magnitudes in Rat Molar

2009 ◽  
Vol 79 (4) ◽  
pp. 703-714 ◽  
Author(s):  
Carmen Gonzales ◽  
Hitoshi Hotokezaka ◽  
Yoshinori Arai ◽  
Tadashi Ninomiya ◽  
Junya Tominaga ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Three Dimensional ◽  
Element Model ◽  
Longitudinal Change ◽  
Micro Ct ◽  
Linear Measurements ◽  
Center Of Rotation ◽  
Ct Evaluation ◽  
Space Width

Abstract Objective: To investigate the precise longitudinal change in the periodontal ligament (PDL) space width and three-dimensional tooth movement with continuous-force magnitudes in living rats. Materials and Methods: Using nickel-titanium closed-coil springs for 28 days, 10-, 25-, 50-, and 100-g mesial force was applied to the maxillary left first molars. Micro-CT was taken in the same rat at 0, 1, 2, 3, 10, 14, and 28 days. The width of the PDL was measured in the pressure and tension sides from 0 to 3 days. Angular and linear measurements were used to evaluate molar position at day 0, 10, 14, and 28. The finite element model (FEM) was constructed to evaluate the initial stress distribution, molar displacement, and center of rotation of the molar. Results: The initial evaluation of PDL width showed no statistical differences among different force magnitudes. Tooth movement was registered 1 hour after force application and gradually increased with time. From day 10, greater tooth movement was observed when 10 g of force was applied. The FEM showed that the center of rotation in the molar is located in the center of five roots at the apical third of the molar roots. Conclusion: The rat's molar movement mainly consists of mesial tipping, extrusion of distal roots, intrusion of mesial root, palatal inclination, and mesial rotation. Although the initial tooth movement after the application of different force magnitudes until day 3 was not remarkably different, 10 g of force produced more tooth movement compared with heavier forces at day 28.

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