The Vascular Architecture of Cavernous Sinus Dural Arteriovenous Fistula and Its Impact on Endovascular Treatment Approach Selection and Outcome

BACKGROUND

A cavernous sinus (CS) dural arteriovenous fistula (DAVF) is a form of abnormal arteriovenous communication that can be treated with endovascular embolization. Establishing an optimal access route should be based on vascular architecture. We reviewed 64 patients with CS-DAVF who underwent endovascular embolization and report the endovascular treatment approach selection and outcome.

METHODS

Clinical data were obtained from 64 patients with CS-DAVF who had been surgically treated at the authors' hospital between 2009 and 2022. Patients' medical records, imaging data, and follow-up outcomes were retrospectively analyzed.

RESULTS

All 64 patients (15 male, 49 female; mean age, 50 years) underwent CS-DAVF embolization. The most common symptoms were exophthalmos (39.1%), chemosis (35.9%), and headache (28.1%). On digital subtraction angiography images, 34.4% of the DAVFs were unilateral, and 82.8% were fed by both the external carotid artery and internal carotid artery. Of the patients' inferior petrosal sinuses (IPSs), 54.7% were nonopacified. The most common intravascular approaches included trans-IPS (37.5%) and trans-artery (28.1%) approaches. More than half of the CS-DAVFs were embolized by both coils and Onyx (62.5%). A total of 85.9% of the fistulas were completely embolized, and the follow-up rate was 76.6%. The modified Rankin Scale score was 0.9 ± 1.0.

CONCLUSIONS

The vascular architecture of CS-DAVF is closely related to endovascular treatment approach selection and outcome. Combined with the modified IPS recanalization technique, the trans-IPS approach is the safest and most effective approach. Dual microcatheter and balloon assistance techniques ensure the safety and completeness of embolization.

EyeCi: Optical clearing and imaging of immunolabeled mouse eyes using light-sheet fluorescence microscopy

Immunofluorescent imaging is an indispensable technique to study morphology and molecular aspects in tissues. Classical approaches make it necessary to cut physical sections of tissue samples to overcome the limited penetration depth of light, restricting the available information to two dimensions. Recent advances in tissue-clearing techniques enable imaging of fluorescently labeled organs and entire organisms on a cellular level in three dimensions without the need of sectioning. Volume imaging of immunolabeled and cleared tissues started a new era of systems biology, because these techniques provide information on connectivity and circuits, especially in structures with projections in three dimensions such as vascular or nervous systems. The variety of published clearing protocols allows the imaging of every organ with a single exception: the eye. Whole-eye clearing approaches were unsuccessful so far due to the strong pigmentation of the retinal pigment epithelium. Here, we present a new protocol that combines a highly effective melanin bleaching step with solvent-based clearing, termed EyeCi. The protocol is compatible with immunolabeling as demonstrated by the visualization of ocular and retinal vasculature in the intact mouse eye by means of light-sheet fluorescence microscopy. This novel protocol is rapid (1 week) and inexpensive, hence allowing high-throughput, high resolution analysis of vascular architecture of healthy and diseased eyes, in its native, three-dimensional organization within intact eyeballs. Volume imaging of whole cleared eyeballs further enables three-dimensional surface reconstruction and automated quantification of choroidal and retinal vasculature extending ocular imaging to a global level. Thus, EyeCi represents an extension to state-of-the-art light microscopy techniques and is potentially suitable for the investigation of vascular leakage or neovascularization processes.

Vascular architecture in free flaps: Analysis of vessel morphology and morphometry in murine free flaps

The aim of this study was to analyze the development of vascular architecture as well as vascular morphometry and morphology of anastomosed microvascular free flaps. Free pectoral skin flaps were raised in 25 rats and anastomosed to the femoral vessels in the groin region. CD31 immunohistology was performed after 3, 7 and 12 d (each 5 animals each) to analyze microvessel density (MVD), microvessel area (MVA) and microvessel size (MVS). Microvascular corrosion casting was performed after 7 and 12 d (5 animals each) to analyze vessel diameter (VD), intervascular distance (IVD), interbranching distance (IBD), and branching angle (BA). Further on, sprout and pillar density as hallmarks of sprouting and intussusceptive angiogenesis were analyzed. Pectoral skin isles from the contralateral side served as controls. A significantly increased MVD was found after 7 and 12 d (p each <0.001). MVA was significantly increased after 3, 7 and 12 d (p each <0.001) and a significantly increased MVS was analyzed after 3 and 7 d (p each <0.001). VD and IVD were significantly increased after 7 and 12 d (p each <0.001). For IBD, a significantly increase was measured after 7 d (p < 0.001). For IBA, sprout and pillar density, no significant differences were found (p each ≥0.05). Significant changes in the vascular architecture of free flaps after successful microvascular anastomosis were seen. Since there was no evidence for sprout and pillar formation within the free flaps, the increased MVD and flap revascularization might be induced by the receiving site.

Physiological, vascular and nanomechanical assessment of hybrid poplar leaf traits in micropropagated plants and plants propagated from root cuttings: A contribution to breeding programs

Micropropagated plants experience significant stress from rapid water loss when they are transferred from an in vitro culture to either greenhouse or field conditions. This is caused both by inefficient stomatal control of transpiration and the change to a higher light intensity and lower humidity. Understanding the physiological, vascular and biomechanical processes that allow micropropagated plants to modify their phenotype in response to environmental conditions can help to improve both field performance and plant survival. To identify changes between the hybrid poplar [Populus tremula × (Populus × canescens)] plants propagated from in vitro tissue culture and those from root cuttings, we assessed leaf performance for any differences in leaf growth, photosynthetic and vascular traits, and also nanomechanical properties of the tracheary element cell walls. The micropropagated plants showed significantly higher values for leaf area, leaf length, leaf width and leaf dry mass. The greater leaf area and leaf size dimensions resulted from the higher transpiration rate recorded for this stock type. Also, the micropropagated plants reached higher values for chlorophyll a fluorescence parameters and for the nanomechanical dissipation energy of tracheary element cell walls which may indicate a higher damping capacity within the primary xylem tissue under abiotic stress conditions. The performance of the plants propagated from root cuttings was superior for instantaneous water-use efficiency which signifies a higher acclimation capacity to stressful conditions during a severe drought particularly for this stock type. Similarities were found among the majority of the examined leaf traits for both vegetative plant origins including leaf mass per area, stomatal conductance, net photosynthetic rate, hydraulic axial conductivity, indicators of leaf midrib vascular architecture, as well as for the majority of cell wall nanomechanical traits. This research revealed that there were no drawbacks in the leaf physiological performance which could be attributed to the micropropagated plants of fast growing hybrid poplar.