The purpose of this study is to present a new semi-automated methodology for threedimensional (3D) reconstruction of coronary arteries and their plaque morphology using Computed Tomography Angiography (CTA) images. The methodology is summarized in seven stages: pre-processing of the acquired CTA images, extraction of the vessel tree centerline, estimation of a weight function for lumen, outer wall and calcified plaque, lumen segmentation, outer wall segmentation, plaque detection, and finally 3D surfaces construction.The methodology was evaluated using both expert's manual annotations and estimations of a recently presented Intravascular Ultrasound (IVUS) reconstruction method. As far as the manual annotation validation process is concerned, the mean value of the comparison metrics for the 3D segmentation were 0.749 and 1.746 for the Dice coefficient and Hausdorff distance, respectively. On the other hand, the correlation coefficients for the degree of stenosis 1, the degree of stenosis 2, the plaque burden, the minimal lumen area and the minimal lumen diameter, when comparing the derived from the proposed methodology 3D models with the IVUS reconstructed models, were 0.79, 0.77, 0.75, 0.85, 0.81, respectively. The proposed methodology is an innovative approach for reconstruction of coronary arteries, since it provides 3D models of the lumen, the outer wall and the CP plaques, using the minimal user interaction.Its first implementation demonstrated that it provides an accurate reconstruction of coronary arteries and thus, it may have a wide clinical applicability.

This MR imaging protocol is a safe and well-tolerated method for evaluating disease activity and extraintestinal manifestations of IBD in children.

Objectives Application of computational fluid dynamics (CFD) to three-dimensional CTCA datasets has been shown to provide accurate assessment of the hemodynamic significance of a coronary lesion. We aim to test the feasibility of calculating a novel CTCA-based virtual functional assessment index (vFAI) of coronary stenoses >30% and ≤90% by using an automated in-house developed software and to evaluate its efficacy as compared to the invasively measured fractional flow reserve (FFR). Methods and results In 63 patients with chest pain symptoms and intermediate (20-90%) pre-test likelihood of coronary artery disease undergoing CTCA and invasive coronary angiography with FFR measurement, vFAI calculations were performed after 3D reconstruction of the coronary vessels and flow simulations using the Finite Element Method. A total of 74 vessels were analysed. Mean CTCA processing time was 25(±10) minutes. There was a strong correlation between vFAI and FFR, (R=0.93, p<0.001) and a very good agreement between the two parameters by the Bland-Altman method of analysis. The mean difference of measurements from the two methods was 0.03 (SD=0.033), indicating a small systematic overestimation of the FFR by vFAI. Using a receiver-operating characteristic curve analysis, the optimal vFAI cutoff value for identifying an FFR threshold of ≤0.8 was ≤0.82 (95% CI: 0.81 to 0.88). Conclusions vFAI can be effectively derived from the application of Computational Fluid Dynamics to threedimensional CTCA datasets. In patients with coronary stenoses severity >30% and ≤90%, vFAI performs well against FFR and may efficiently distinguish between hemodynamically significant from non significant lesions.

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We present the contrast-enhanced spiral CT findings in a case of acute celiac artery occlusion with gastric perforation and total splenic infarction. Spiral CT depicted thrombus in the celiac axis and its branches, stenosis of the superior mesenteric artery, splenic infarction and lack of enhancement of the gastric wall with a large necrotic gap. Spiral CT enabled prompt diagnosis and therapy in this rare condition in a patient with suspicion of acute mesenteric ischemia.