Browsing by Author "Filipovic, N. (35749660900)"

Objectives: The study aimed to identify differences and compare anatomical and biomechanical features between elective and ruptured abdominal aortic aneurysms (AAAs). Methods: Data (clinical, anatomical, and biomechanical) of 98 patients with AAA, 75 (76.53%) asymptomatic (Group aAAA) and 23 (23.46%) ruptured AAA (Group rAAA), were prospectively collected and analyzed. Anatomical, morphological, and biomechanical imaging markers like peak wall stress (PWS) and rupture risk equivalent diameter (RRED), comorbid conditions, and demographics were compared between the groups. Biomechanical features were assessed by analysis of Digital Imaging and Communication in Medicine images by A4clinics (Vascops), and anatomical features were assessed by 3Surgery (Trimensio). Binary and multiple logistic regression analysis were used and adjusted for confounders. Accuracy was assessed using receiving operative characteristic (ROC) curve analysis. Results: In a multivariable model, including gender and age as confounder variables, maximal aneurysm diameter [MAD, odds ratio (OR) = 1.063], relative intraluminal thrombus (rILT, OR = 1.039), and total aneurysm volume (TAV, OR = 1.006) continued to be significant predictors of AAA rupture with PWS (OR = 1.010) and RRED (OR = 1.031). Area under the ROC curve values and correct classification (cc) for the same parameters and the model that combines MAD, TAV, and rILT were measured: MAD (0.790, cc = 75%), PWS (0.713, cc = 73%), RRED (0.717, cc = 55%), TAV (0.756, cc = 79%), rILT (0.656, cc = 60%), and MAD + TAV + rILT (0.797, cc = 82%). Conclusion: Based on our results, in addition to MAD, other important predictors of rupture that might be used during aneurysm surveillance are TAV and rILT. Biomechanical parameters (PWS, RRED) as valuable predictors should be assessed in prospective clinical trials. Similar studies on AAA smaller than 55 mm in diameter, even difficult to organize, would be of even greater clinical value. 2023 Koncar, Nikolic, Milosevic, Bogavac-Stanojevic, Ilic, Dragas, Sladojevic, Markovic, Vujcic, Filipovic and Davidovic.

The aim of this study was to demonstrate how fluid dynamic parameters are affected by aortic geometry and flow condition in two cases. Case A included blood flow analysis in aortic system with abdominal aortic aneurysm and left common iliac aneurysm before stent graft placement, while in case B was included stent graft geometry, at the site of the aneurysms. An individual patient-specific geometry and a 3D finite element meshes were reconstructed, based on Computed tomography (CT) scan images. The analysis was performed using the possibilities of computational fluid dynamics. It uses numeric methods and algorithms for the simulation of blood flow by solving the Navier-Stokes equations on computational meshes. The computational simulations of cardiac cycles were performed for average blood properties and blood flow rate. The velocity field, pressure and shear stress, as main fluid dynamics parameters, were visualized and compared for cases A and B. © 2018 S. Djorovic et al.

The aim of this study was to demonstrate how fluid dynamic parameters are affected by aortic geometry and flow condition in two cases. Case A included blood flow analysis in aortic system with abdominal aortic aneurysm and left common iliac aneurysm before stent graft placement, while in case B was included stent graft geometry, at the site of the aneurysms. An individual patient-specific geometry and a 3D finite element meshes were reconstructed, based on Computed tomography (CT) scan images. The analysis was performed using the possibilities of computational fluid dynamics. It uses numeric methods and algorithms for the simulation of blood flow by solving the Navier-Stokes equations on computational meshes. The computational simulations of cardiac cycles were performed for average blood properties and blood flow rate. The velocity field, pressure and shear stress, as main fluid dynamics parameters, were visualized and compared for cases A and B. © 2018 S. Djorovic et al.

It has been suggested that unerupted lower third molars (M3) increase the fragility of the mandibular angle and simultaneously decrease the risk of condylar fracture. However, it is unknown whether this applies regardless of the direction and point of impact of the traumatic force. The aim of this study was to investigate the impact of an unerupted M3 on the fragility of the angle and condyle in terms of a force acting from different directions and affecting different regions of the mandible. Computed tomography scans of a human mandible and finite element methodology were used to obtain two three-dimensional models: a model with, and the other without an unerupted M3. A force of 2000 N was applied to three different regions of the models: the symphysis, ipsilateral body, and contralateral body, respectively. When the force was applied to the mandibular body, the results revealed increased angle fragility in cases with unerupted M3. When the force was applied to the symphysis, the condyle region showed higher fragility, irrespective of the presence of an unerupted M3. In summary, fragility of the angle and condyle regions depends on the presence of an unerupted M3 and on the direction and point of impact of the force. © 2014 International Association of Oral and Maxillofacial Surgeons

It has been suggested that unerupted lower third molars (M3) increase the fragility of the mandibular angle and simultaneously decrease the risk of condylar fracture. However, it is unknown whether this applies regardless of the direction and point of impact of the traumatic force. The aim of this study was to investigate the impact of an unerupted M3 on the fragility of the angle and condyle in terms of a force acting from different directions and affecting different regions of the mandible. Computed tomography scans of a human mandible and finite element methodology were used to obtain two three-dimensional models: a model with, and the other without an unerupted M3. A force of 2000 N was applied to three different regions of the models: the symphysis, ipsilateral body, and contralateral body, respectively. When the force was applied to the mandibular body, the results revealed increased angle fragility in cases with unerupted M3. When the force was applied to the symphysis, the condyle region showed higher fragility, irrespective of the presence of an unerupted M3. In summary, fragility of the angle and condyle regions depends on the presence of an unerupted M3 and on the direction and point of impact of the force. © 2014 International Association of Oral and Maxillofacial Surgeons

The role of intraluminal thrombus (ILT) has special attention in these studies. One of the papers showed that asymmetrical intraluminal thrombus deposition (ATDI) has an important role in growth of the AAA. The aim of our study was to assess the asymmetrical thrombus deposition index in ruptured and symptomatic aneurysms. We collected data for 33 aneurysms, 21 (63.63%) asymptomatic and 12 (33.37%) ruptured or symptomatic. Asymmetrical thrombus deposition index (ATDI) was measured by Onis DICOM viewer software. Also, lumen's geometrical centre (LGC) was defined and ATDI was considered positive when the LGC was laid on the posterior section of the sac (meaning dominant anterior ILT distribution) and negative when it was laid on the anterior section (meaning dominant posterior ILT distribution). Maximum aneurysm diameter was 63.4mm in average (50-100mm, SD=12.89); 59.8mm in asymptomatic and 71.16mm in symptomatic or ruptured aneurysm (p=0.012). The absolute value of asymmetric thrombus deposition index was significantly higher in symptomatic/ruptured compared to asymptomatic aneurysm, 0.54 and 0.33, respectively (p=0.041), while there was no difference in frequency of positive or negative thrombus deposition (p=0.261). There was no significant correlation between maximal aneurysm size and absolute value of ATDI (p=0.505). Values of thrombus deposition index are correlating with the development of symptomatology or rupture of the AAA. This variable should be included in much wider mathematical rupture prediction model in order to have more accurate rupture risk assessment. © 2015 IEEE.

The role of intraluminal thrombus (ILT) has special attention in these studies. One of the papers showed that asymmetrical intraluminal thrombus deposition (ATDI) has an important role in growth of the AAA. The aim of our study was to assess the asymmetrical thrombus deposition index in ruptured and symptomatic aneurysms. We collected data for 33 aneurysms, 21 (63.63%) asymptomatic and 12 (33.37%) ruptured or symptomatic. Asymmetrical thrombus deposition index (ATDI) was measured by Onis DICOM viewer software. Also, lumen's geometrical centre (LGC) was defined and ATDI was considered positive when the LGC was laid on the posterior section of the sac (meaning dominant anterior ILT distribution) and negative when it was laid on the anterior section (meaning dominant posterior ILT distribution). Maximum aneurysm diameter was 63.4mm in average (50-100mm, SD=12.89); 59.8mm in asymptomatic and 71.16mm in symptomatic or ruptured aneurysm (p=0.012). The absolute value of asymmetric thrombus deposition index was significantly higher in symptomatic/ruptured compared to asymptomatic aneurysm, 0.54 and 0.33, respectively (p=0.041), while there was no difference in frequency of positive or negative thrombus deposition (p=0.261). There was no significant correlation between maximal aneurysm size and absolute value of ATDI (p=0.505). Values of thrombus deposition index are correlating with the development of symptomatology or rupture of the AAA. This variable should be included in much wider mathematical rupture prediction model in order to have more accurate rupture risk assessment. © 2015 IEEE.