Search Results (9)

Background/Objectives: The aim of the current investigation was to assess the short-term changes in retinal-choroidal vasculature and the morphological complexity of non-exudative macular neovascularization (NE-MNV) using optical coherence tomography angiography (OCTA) and spectral-domain optical coherence tomography (SD-OCT). Methods: Sixteen eyes of 12 patients with NE-MNV underwent baseline and six-month follow-up examinations, including comprehensive ophthalmological assessment and imaging. Central macular thickness, foveal avascular zone, vessel density, flow area, and choroidal vascularity index were analyzed. NE-MNV morphology was quantitatively assessed for area, vessel characteristics, and fractal dimensions. Results: Significant changes in NE-MNV morphology were noted over six months, especially in fractal dimensions, vessel junctions, and vessel length (p-values: 0.01, 0.037, and 0.036, respectively). While there was an increase in the NE-MNV area, it did not reach statistical significance. No significant changes were shown regarding the standard SD-OCT and OCTA output parameters or choroidal measurements. Conclusions: The increase in NE-MNV fractal dimensions suggests rising complexity in the neovascular network and may indicate possible implications for clinical management. The correlation between baseline and follow-up measures underscores a trend toward complexity, pointing to the necessity for closer monitoring of patients with higher NE-MNV fractal dimensions. Full article

Angiogenesis is acknowledged as a pivotal feature in the pathology of human cancer. Despite the absence of universally accepted markers for gauging the comprehensive angiogenic activity in prostate cancer (PCa) that could steer the formulation of focused anti-angiogenic treatments, the scrutiny of diverse facets of tumoral blood vessel development may furnish significant understanding of angiogenic processes. Malignant neoplasms, encompassing PCa, deploy a myriad of strategies to secure an adequate blood supply. These modalities range from sprouting angiogenesis and vasculogenesis to intussusceptive angiogenesis, vascular co-option, the formation of mosaic vessels, vasculogenic mimicry, the conversion of cancer stem-like cells into tumor endothelial cells, and vascular pruning. Here we provide a thorough review of these angiogenic mechanisms as they relate to PCa, discuss their prospective relevance for predictive and prognostic evaluations, and outline the prevailing obstacles in quantitatively evaluating neovascularization via histopathological examinations. Full article

Anti-VEGF (vascular endothelial growth factor) treatment improves response rates, but not progression-free or overall survival in advanced breast cancer. It has been suggested that subgroups of patients may benefit from this treatment; however, the effects of adding anti-VEGF treatment to a standard chemotherapy regimen in breast cancer patients are not well studied. Understanding the effects of the anti-vascular treatment on tumor vasculature may provide a selection of patients that can benefit. The aim of this study was to study the vascular effect of bevacizumab using clinical dynamic contrast-enhanced MRI (DCE-MRI). A total of 70 women were randomized to receive either chemotherapy alone or chemotherapy with bevacizumab for 25 weeks. DCE-MRI was performed at baseline and at 12 and 25 weeks, and in addition 25 of 70 patients agreed to participate in an early MRI after one week. Voxel-wise pharmacokinetic analysis was performed using semi-quantitative methods and the extended Tofts model. Vascular architecture was assessed by calculating the fractal dimension of the contrast-enhanced images. Changes during treatment were compared with baseline and between the treatment groups. There was no significant difference in tumor volume at any point; however, DCE-MRI parameters revealed differences in vascular function and vessel architecture. Adding bevacizumab to chemotherapy led to a pronounced reduction in vascular DCE-MRI parameters, indicating decreased vascularity. At 12 and 25 weeks, the difference between the treatment groups is severely reduced. Full article

Convective transport of drug solutes in biological tissues is regulated by the interstitial fluid pressure, which plays a crucial role in drug absorption into the lymphatic system through the subcutaneous (SC) injection. In this paper, an approximate continuum poroelasticity model is developed to simulate the pressure evolution in the soft porous tissue during an SC injection. This poroelastic model mimics the deformation of the tissue by introducing the time variation of the interstitial fluid pressure. The advantage of this method lies in its computational time efficiency and simplicity, and it can accurately model the relaxation of pressure. The interstitial fluid pressure obtained using the proposed model is validated against both the analytical and the numerical solution of the poroelastic tissue model. The decreasing elasticity elongates the relaxation time of pressure, and the sensitivity of pressure relaxation to elasticity decreases with the hydraulic permeability, while the increasing porosity and permeability due to deformation alleviate the high pressure. An improved Kedem–Katchalsky model is developed to study solute transport across the lymphatic vessel network, including convection and diffusion in the multi-layered poroelastic tissue with a hybrid discrete-continuum vessel network embedded inside. At last, the effect of different structures of the lymphatic vessel network, such as fractal trees and Voronoi structure, on the lymphatic uptake is investigated. In this paper, we provide a novel and time-efficient computational model for solute transport across the lymphatic vasculature connecting the microscopic properties of the lymphatic vessel membrane to the macroscopic drug absorption. Full article

The study population contains 145 patients who were prospectively recruited for coronary CT angiography (CCTA) and fundoscopy. This study first examined the association between retinal vascular changes and the Coronary Artery Disease Reporting and Data System (CAD-RADS) as assessed on CCTA. Then, we developed a graph neural network (GNN) model for predicting the CAD-RADS as a proxy for coronary artery disease. The CCTA scans were stratified by CAD-RADS scores by expert readers, and the vascular biomarkers were extracted from their fundus images. Association analyses of CAD-RADS scores were performed with patient characteristics, retinal diseases, and quantitative vascular biomarkers. Finally, a GNN model was constructed for the task of predicting the CAD-RADS score compared to traditional machine learning (ML) models. The experimental results showed that a few retinal vascular biomarkers were significantly associated with adverse CAD-RADS scores, which were mainly pertaining to arterial width, arterial angle, venous angle, and fractal dimensions. Additionally, the GNN model achieved a sensitivity, specificity, accuracy and area under the curve of 0.711, 0.697, 0.704 and 0.739, respectively. This performance outperformed the same evaluation metrics obtained from the traditional ML models (p < 0.05). The data suggested that retinal vasculature could be a potential biomarker for atherosclerosis in the coronary artery and that the GNN model could be utilized for accurate prediction. Full article

Background: The clinical appearance of macular neovascularization (MNV) in age-related macular degeneration (nAMD) varies widely, but so far, this has had no relevance in terms of therapeutic approaches or prognosis. Therefore, our purpose was to investigate if and which differences exist in the vascular architecture of MNV and to quantify them. Methods: In 90 patients with newly diagnosed nAMD, MNV was identified by means of optical coherence tomography angiography (OCTA), and automated quantitative vascular analysis was carried out. The analyzed vascular parameters were area, flow, fractal dimension (FD), total vascular length (sumL), number of vascular nodes (numN), flow, and average vessel caliber (avgW). The current classification of MNVs divides them according to their localization into type 1 (grown from the choroid below the RPE), type 2 (grown from the choroid through RPE), and type 3 (grown from the retina toward the RPE). We compared the analyzed vascular parameters of each of the three MNV types. Kruskal–Wallis test was applied, Dunn test was performed for post hoc analysis, and for pairwise comparison, p-values were adjusted using Bonferroni comparison. Results: Regarding the MNV area, there was no significant difference between types 1 and 2, but type 3 was significantly smaller than types 1 and 2 (p < 0.00001). For FD, types 1 and 2 did not differ significantly, but again, type 3 was lower than type 1 and 2 (p < 0.00001). The numN were significantly higher in types 1 and 3 than in 2 (p < 0.005), but not between types 1 and 3. No significant differences were found between MNV types for flow. As for sumL, types 1 and 2 did not differ significantly, but type 3 was significantly lower than types 1 and 2 (p < 0.00001). For avgW, there was no significant difference between types 1 and 2 or between types 2 and 3, but type 3 was significantly larger than type 1 (p < 0.05). Conclusions OCTA yields detailed information on the vascular morphology of MNV in patients with nAMD and is able to show differences among types 1, 2, and 3. Especially comparing types 1 and 2 with type 3 reveals significant differences in area, FD, sumL, and numN. One explanation could be the similar pathogenesis of types 1 and 2 with their origin in the choroid and their growth towards the retinal pigment epithelium (RPE), whereas type 3 originates in the deep capillary plexus. Between types 1 and 2, however, only the numN differ significantly, which could be due to the fact that type 1 spreads horizontally below the RPE and, thus, display more vascular branching, while type 2 grows more vertically through the RPE and under the neurosensory retina. Detailed information about the pathologic vasculature is important for proper monitoring of the disease and to assess the efficacy of medication, especially with regard to new substances. This should be taken into consideration in future studies. Full article

Carfilzomib is mainly used to treat multiple myeloma. Several side effects have been reported in patients treated with carfilzomib, especially those associated with cardiovascular events, such as hypertension, congestive heart failure, and coronary artery disease. However, the side effects, especially the manifestation of cardiovascular events through capillaries, have not been fully investigated. Here, we performed a pilot experiment to monitor peripheral vascular dynamics in a mouse ear under the effects of carfilzomib using a quantitative photoacoustic vascular evaluation method. Before and after injecting the carfilzomib, bortezomib, and PBS solutions, we acquired high-resolution three-dimensional PAM data of the peripheral vasculature of the mouse ear during each experiment for 10 h. Then, the PAM maximum amplitude projection (MAP) images and five quantitative vascular parameters, i.e., photoacoustic (PA) signal, diameter, density, length fraction, and fractal dimension, were estimated. Quantitative results showed that carfilzomib induces a strong effect on the peripheral vascular system through a significant increase in all vascular parameters up to 50%, especially during the first 30 min after injection. Meanwhile, bortezomib and PBS do not have much impact on the peripheral vascular system. This pilot study verified PAM as a comprehensive method to investigate peripheral vasculature, along with the effects of carfilzomib. Therefore, we expect that PAM may be useful to predict cardiovascular events caused by carfilzomib. Full article

Ultrasound imaging of the liver is an everyday, worldwide clinical tool. The echoes are produced by inhomogeneities within the interrogated tissue, but what are the mathematical properties of these scatterers? In theory, the spatial correlation function and the backscatter coefficient are linked by a Fourier transform relationship, however direct measures of these are relatively rare. Under the hypothesis that the fractal branching vasculature and fluid channels are the predominant source of scattering in normal tissues, we compare theory and experimental measures of the autocorrelation function, the frequency dependence of scattering, and fractal dimension estimates from high contrast 3D micro-CT data sets of rat livers. The results demonstrate a fractal dimension of approximately 2.2 with corresponding power law estimates of autocorrelation and ultrasound scattering. These results support a general framework for the analysis of ultrasound scattering from soft tissues. Full article

The fractal branching vasculature within soft tissues and the mathematical properties of the branching system influence a wide range of important phenomena from blood velocity to ultrasound backscatter. Among the mathematical descriptors of branching networks, the spatial autocorrelation function plays an important role in statistical measures of the tissue and of wave propagation through the tissue. However, there are open questions about analytic models of the 3D autocorrelation function for the branching vasculature and few experimental validations for soft vascularized tissue. To address this, high resolution computed tomography scans of a highly vascularized placenta perfused with radiopaque contrast through the umbilical artery were examined. The spatial autocorrelation function was found to be consistent with a power law, which then, in theory, predicts the specific power law behavior of other related functions, including the backscatter of ultrasound. Full article