Surgical ventricular restoration (SVR) was designed to treat patients with aneurysms or large akinetic walls and dilated ventricles. Yet, crucial aspects essential to the efficacy of this procedure like optimal shape and size of the left ventricle (LV) are still debatable. The objective of this study is to quantify the efficacy of SVR based on LV regional shape in terms of curvedness, wall stress, and ventricular systolic function. A total of 40 patients underwent magnetic resonance imaging (MRI) before and after SVR. Both short-axis and long-axis MRI were used to reconstruct end-diastolic and end-systolic three-dimensional LV geometry. The regional shape in terms of surface curvedness, wall thickness, and wall stress indexes were determined for the entire LV. The infarct, border, and remote zones were defined in terms of end-diastolic wall thickness. The LV global systolic function in terms of global ejection fraction, the ratio between stroke work (SW) and end-diastolic volume (SW/EDV), the maximal rate of change of pressure-normalized stress (dσ*/dt(max)), and the regional function in terms of surface area change were examined. The LV end-diastolic and end-systolic volumes were significantly reduced, and global systolic function was improved in ejection fraction, SW/EDV, and dσ*/dt(max). In addition, the end-diastolic and end-systolic stresses in all zones were reduced. Although there was a slight increase in regional curvedness and surface area change in each zone, the change was not significant. Also, while SVR reduced LV wall stress with increased global LV systolic function, regional LV shape and function did not significantly improve.

Tan RS, Kassab G. Right ventricular regional wall curvedness and area strain in patients with repaired tetralogy of Fallot. Am J Physiol Heart Circ Physiol 302: H1306 -H1316, 2012. First published December 30, 2011 doi:10.1152/ajpheart.00679.2011.-A quantitative understanding of right ventricular (RV) remodeling in repaired tetralogy of Fallot (rTOF) is crucial for patient management. The objective of this study is to quantify the regional curvatures and area strain based on three-dimensional (3-D) reconstructions of the RV using cardiac magnetic resonance imaging (MRI). Fourteen (14) rTOF patients and nine (9) normal subjects underwent cardiac MRI scan. 3-D RV endocardial surface models were reconstructed from manually delineated contours and correspondence between end-diastole (ED) and end systole (ES) was determined. Regional curvedness (C) and surface area at ED and ES were calculated as well as the area strain. The RV shape and deformation in rTOF patients differed from normal subjects in several respects. Firstly, the curvedness at ED (mean for 13 segments, 0.030 Ϯ 0.0076 vs. 0.029 Ϯ 0.0065 mm Ϫ1 ; P Ͻ 0.05) and ES (mean for 13 segments, 0.040 Ϯ 0.012 vs. 0.034 Ϯ 0.0072 mm Ϫ1 ; P Ͻ 0.001) was decreased by chronic pulmonary regurgitation. Secondly, the surface area increased significantly at ED (mean for 13 segments, 982 Ϯ 192 vs. 1,397 Ϯ 387 mm 2 ; P Ͻ 0.001) and ES (mean for 13 segments, 576 Ϯ 130 vs. 1,012 Ϯ 302 mm 2 ; P Ͻ 0.001). In particular, rTOF patients had significantly larger surface area than that in normal subjects in the free wall but not for the septal wall. Thirdly, area strain was significantly decreased (mean for 13 segments, 56 Ϯ 6 vs. 34 Ϯ 7%; P Ͻ 0.0001) in rTOF patients. Fourthly, there were increases in surface area at ED (5,726 Ϯ 969 vs. 6,605 Ϯ 1,122 mm 2 ; P Ͻ 0.05) and ES (4,280 Ϯ 758 vs. 5,569 Ϯ 1,112 mm 2 ; P Ͻ 0.01) and decrease in area strain (29 Ϯ 8 vs. 18 Ϯ 8%; P Ͻ 0.001) for RV outflow tract. These findings suggest significant geometric and strain differences between rTOF and normal subjects that may help guide therapeutic treatment. magnetic resonance imaging; curvature; right ventricular remodeling; deformation; three-dimensional reconstruction TETRALOGY OF FALLOT (TOF) is the most common cyanotic congenital heart disease (19). The main features include ventricular septum defect, subpulmonary stenosis, and overriding aorta and right ventricular (RV) hypertrophy. Surgical repair is usually performed in early infancy to widen the passage from the RV to the pulmonary artery and close the ventricular septal defect. This ensures separation of oxygen-rich and oxygenpoor blood flows to the proper chambers. Surgical repair of TOF often involves disruption of pulmonary valve integrity that leads to pulmonary regurgitation (PR; Refs. 8, 37). This in turn causes RV dilation (9, 23) and RV outflow tract (RVOT) aneurysm (2-3, 13, 28 -29). The RV dilation is usually tolerated with little or no symptoms during the first two to three decades of age. If left untreated, however, continued...

<p><strong>Abstract.</strong> Singapore, branded as a “City in a Garden”, has a long standing commitment to green the nation, one which has resulted in trees becoming an integral component of the urban environment. Similarly for its digital twin, Virtual Singapore, we undertake the research to automate the population of this virtual city with semantically and biologically representative trees in a CityGML (City Geography Markup Language) format. This paper presents our framework of modeling trees for Virtual Singapore, showcasing an array of methodologies in data acquisition of light detection and ranging (LiDAR) and satellite images, tree extraction and quantification, and 3D tree modeling at LODs (level of details) 1, 2 and 3. The paper will also highlight challenges and chosen methodologies along with the preliminary results of this framework.</p>