Rete Mirabile Research Articles

Abstract 1122‐000236: Intravascular Delivery and Crosslinking of Photosensitive Hydrogels for Embolizing Animal Models of AVMs and Tumors

Introduction : Embolization represents a minimally invasive treatment modality for arteriovenous malformations (AVMs), tumors, and other indications, but can be limited by currently available embolic agents, in terms of safety and efficacy. Discovery of new and improved agents could lead to better treatment outcomes. The goal of this project was to test a novel embolization methodology for the treatment of AVMs and tumors. Methods : We formulated low‐viscosity, shear‐thinning hydrogel formulations which were mixed with a photo‐initator agent and non‐ionic contrast medium. We then developed a method of intravascular hydrogel delivery with photo crosslinking at the tip of the catheter, using an integrated optical fibre. This allowed for rapid transition from a low viscosity liquid to a crosslinked solid‐state hydrogel to block blood flow to the vascular target. In addition, the UV intensity can be dynamically modulated, in real‐time, to modify the degree of crosslinking and thus the viscosity of the embolic agent. We utilized the swine rete mirabile as an animal model for AVMs, and the swine renal arterial tree (inferior segmental artery) as a model for hypervascular tumors. 5 animals were utilized without prior preparation. Embolization was graded based on degree of complete obliteration of the rete nidus or the renal arterial tree. Any non‐target embolization or other complications were recorded. Follow‐up angiography was performed at the 4‐week interval. Results : With a combination of shear‐thinning properties and dynamic modulation of photo crosslinking, we show that we are able to deliver an embolic agent with a viscosity range of up to 10^4 Pa*s through a single low viscosity precursor that is injectable through microcatheters (Figure 1). Using this methodology, hydrogel embolization was technically successful in all animals. Following embolization, 4/5 rete mirabile and 5/5 inferior renal arterial trees were completely obliterated. Representative angiographic images are shown in Figures 2 and 3. There were no instances of clinical or angiographic complications. Conclusions : We demonstrated a novel method of intravascular delivery of low viscosity photosensitive hydrogels, with photo crosslinking at the tip of the catheter, to successfully embolize animal models for AVMs and tumors. This promising technology will be investigated further with longer‐term comparative animal trials.

Vascular Effects of Pseudoxanthoma Elasticum

Background: Pseudoxanthoma elasticum (PXE) is a rare hereditary disease caused by mutations in the ABCC6 gene, characterized by ectopic calcification of connective tissue throughout the body. Vascular conditions associated with PXE have been well-documented in the literature, but to our knowledge, analysis of the myriad of PXE case reports with associated vascular diseases in addition to larger cohort studies, has not been undertaken.
 Objective: To review existing literature reporting peripheral vascular disease (PVD), cardiovascular disease (CVD), cerebrovascular disease (CeVD), hypertension, and carotid rete mirabile (CRM) in PXE patients as of June 2021.
 Methods: A search of the PubMed database using the key words “pseudoxanthoma elasticum” and “vascular” was performed.
 Results: A total of 345 cases of PVD, 97 cases of CVD, and 123 case of CeVD were reported. Additionally, 88 cases of hypertension and 5 cases of CRM were reported.
 Conclusions: PXE patients are at risk of developing serious vascular conditions, particularly peripheral vascular disease. This condition also appears to have some connection to carotid rete mirabile, which is extremely rare in humans. Further research should be conducted to analyze the connection between PXE and CRM in order to better understand and treat both conditions.

The rostral epidural rete mirabile of the llama as a place of retrograde transport of various substances – anatomical basics

Abstract The aim of this study was to analyse the structure of the rostral epidural rete mirabile in the llama. Some specimens were prepared by injecting stained chemically cured acrylic into the bilateral common carotid arteries. After about 1 month received vascular corrosion casts on the bone scaffold. Some specimens made using red and blue latex introduced into the bilateral common carotid arteries and the bilateral external jugular vein. The rostral epidural rete mirabile is a well-developed, bilateral structure composed of numerous arteries, which are multiply anastomosed with each other. The cranial section of the rete is asymmetrical. Its lateral part is much better developed, because there are rostral branches to the rostral epidural rete mirabile at this point. The arterial vessels are not accompanied by homonymous veins. However, the arteries of the rostral epidural rete mirabile are accompanied by venous vessels of the cavernous sinus. That rete plays an important role in selective brain cooling, the conservation of body water, and retrograde transport of neurotransmitters. CO, GnRH, beta-endorphin, progesterone, testosterone, oxytocin, LHRH and dopamine diffuse from the venous blood of the cavernous sinus to the arterial blood of the rostral epidural rete mirabile.

Histologic Examination of a Sea Pig (Scotoplanes sp.) Using Bright Field Light Microscopy

Sea pigs (Scotoplanes spp.) are deep-sea dwelling sea cucumbers of the phylum Echinodermata, class Holothuroidea, and order Elasipodida. Few reports are available on the microscopic anatomy of these deep-sea animals. This study describes the histologic findings of two, wild, male and female Scotoplanes sp. collected from Monterey Bay, California. Microscopic findings were similar to other holothuroids, with a few notable exceptions. Sea pigs were bilaterally symmetrical with six pairs of greatly enlarged tube feet arising from the lateral body wall and oriented ventrally for walking. Neither a rete mirabile nor respiratory tree was identified, and the large tube feet may function in respiration. Dorsal papillae protrude from the bivium and are histologically similar to tube feet with a large, muscular water vascular canal in the center. There were 10 buccal tentacles, the epidermis of which was highly folded. Only a single gonad was present in each animal; both male and female had histologic evidence of active gametogenesis. In the male, a presumed protozoal cyst was identified in the aboral intestinal mucosa, and was histologically similar to previous reports of coccidians. This work provides control histology for future investigations of sea pigs and related animals using bright field microscopy.

Did Andreas Vesalius’s De Humani Corporis Fabrica and/or Juan Valverde’s Historia De La Composicion Del Cuerpo Humano Really Influence the Anatomy Knowledge in the Ottoman Empire? A Preliminary Study on Shams al-Dīn ʿItāqī’s Tashrīh al-Abdān*

Aim of this study was to determine whether Vesalius and Valverde influenced Shams al-Dīn ʿItāqī considering the figures and several statements in Tashrīḥ al-Abdān wa Tarjamān Qibāla Faylasūfān. The statements and figures in illustrated copies of ʿItāqī’s book were examined and compared to those in Galen’s, Avicenna’s, Vesalius’s, and Valverde’s works, then the findings were evaluated. ʿItāqī’s book contains some figures only from Vesalius and/or Valverde’s works, but there is no new explanation related to issues such as the mandible, the sacrum, the rete mirabile, and the uterus. The Latin edition of Valverde’s book published in 1607 was probably the source of the Western-originated illustrations in the manuscript Hüsrev Paşa, Nr. 464 and of all the Western-based illustrations, except for the female figure in the manuscript of Istanbul University, Turkish Manuscripts, TY 2662. Spanish and/or Italian and/or Latin (1589) editions of Valverde’s book were the sources of most of the Western-originated illustrations, except the human skeleton figure in the manuscript of Prof. Uzluk’s personal collection. The information given by the works of Vesalius and Valverde has not influenced the explanations of ʿItāqī. ʿItāqī wrote his book according to the classical anatomical knowledge in the Islamic world of his era and he added Eastern- and Western-originated figures to his book to support/strengthen his statements. Or ʿItāqī work Tasrīḥ al-Abdān originally contained no illustrations. However, later, scribes/copiers added Eastern- and Western-originated anatomical figures to the book to support/strengthen statements at different times.

The structure of the rostral epidural rete mirabile in selected representatives of the Cervidae and Bovidae families

AbstractThe rostral epidural rete mirabile appears in many studies on cerebral vascularisation; however, its exact characteristics are poorly understood. Its structure and location have a mechanism of selective cooling of the brain, protecting the animal from hyperthermia and affecting the body water balance. The aim of this study was to analyse the structure of the rostral epidural rete mirabile along with its tributaries. The study material consisted of a total of 61 specimens from the deer family belonging to the European roe deer, red deer and fallow deer species and those belonging to the beef family: domestic cattle, European bison, domestic sheep and domestic goat. The rostral epidural rete mirabile in the families of this study is well developed. It is formed of many small arteries anastomosing with each other and its main tributary is the maxillary artery, which is an extension of the external carotid artery. Additionally, in cervids, blood is supplied by the condylar artery. Within the families analysed, there was considerable similarity in the plan of construction within the rostral epidural rete mirabile, with minor differences among individual taxa.

Vertebrobasilar Contribution to Cerebral Arterial System of Dromedary Camels (Camelus dromedarius).

It is hypothesized that in the “more highly evolved” mammals, including the domesticated mammals, that the brainstem and the cerebellum receive arterial blood through the vertebrobasilar system whilst the internal carotid arteries primarily supply the forebrain. In camels, the arterial blood supply to the brain differs from that of ruminants since the internal carotid artery and the rostral epidural rete mirabile (RERM) are both present and the basilar artery contributes a significant proportion of cerebral afferent blood. In this study, we described the anatomical distribution of the vertebrobasilar system arterial supply in the dromedary. Secondly, we determined the direction of blood flow within the vertebral and basilar arteries using transcranial color doppler ultrasonography. Thirdly, we quantified the percentage arterial contributions of the carotid and vertebrobasilar systems to the dromedary brain. Fifty-five heads of freshly slaughtered male Omani dromedaries aged 2–6 years were dissected to determine the distribution and topography of the arterial distribution to the brain. Their anatomical orientation was assessed by casting techniques using epoxy resin, polyurethane resin and latex neoprene. The epoxy resin and polyurethane resin casts of the head and neck arteries were used to measure the diameter of vertebrobasilar arterial system and carotid arterial system at pre-determined locations. These arterial diameters were used to calculate the percentage of blood supplied by each arterial system. The vertebrobasilar system in dromedary camels consists of paired vertebral arteries that contribute to the ventral spinal artery and basilar artery at multiple locations. In most specimens the vertebral artery was the primary contributor to the basilar artery compared to that of the ventral spinal artery. In four specimens the ventral spinal arteries appear to be the dominant contributor to the basilar artery. Transcranial color doppler ultrasonography confirmed that the direction of blood flow within the vertebral and basilar arteries was toward the brain in animals examined in ventral recumbency and when standing. The vertebrobasilar system contributes 34% of the blood supply to the brain. The vertebrobasilar system is the exclusive supply to the medulla oblongata, pons and cerebellum.

Active Blood Acidification Greatly Enhances Oxygen Supply to the Teleost Retina

Most ray-finned fishes possess a unique system for retinal oxygen delivery, where intracellular acidification of red blood cells (RBCs) in the retinal capillaries induces oxygen offloading from pH-sensitive hemoglobin. A countercurrent vascular network, the choroid rete mirabile, posterior to the retina augments this “oxygen-secretory” mechanism and confers retinal PO2 values that can exceed 1300 mmHg in some species. We hypothesized that the choroid rete mirabile exerts an active role in intracellular RBC acidification to facilitate retinal oxygen secretion. We show the presence and enzymatic activities of extracellular carbonic anhydrase (CA) and vacuolar-type H+-ATPase (VHA) in the lumen of the choroid rete mirabile. These data are consistent with a pathway, where VHA secretes H+ into the choroid rete mirabile lumen, which combines with HCO3– to form CO2 (catalyzed by extracellular CA) that rapidly diffuses into the RBC facilitating hemoglobin oxygen offloading. Next, we validated the model in vivo by injecting an extracellular CA inhibitor (C18) into the dorsal aorta of anesthetized rainbow trout with a PO2 electrode implanted into the retina. Here, the inhibition of extracellular CA resulted in a rapid reduction in retinal PO2 from 517 to 226 mmHg within minutes. These data strongly support the proposed model for RBC acidification in the choroid rete mirabile. Further, in vivo data show that this mechanism primarily augments oxygen diffusion to the inner retinal segments involved in signal-processing and that the evolution of this pathway was tightly associated with the morphological expansion of this part of the retina. Together, these data suggest that the evolutionary origin of retinal oxygen secretion in the early history of the ray-finned fishes was associated with a greatly enhanced capacity for visual processing, potentially permitting improved visual prey detection and the colonization of novel environments.

The Endocranial Cast of Indohyus (Artiodactyla, Raoellidae): The Origin of the Cetacean Brain

We present the first description of the endocranial cast of the small raoellid artiodactyl Indohyus indirae. Raoellidae are sister group to Cetacea and the new morphological observations allow for outlining some of the early steps of the evolutionary history of the cetacean brain. The combination of primitive artiodactyl features and typical cetacean characters is unique about the Indohyus endocast. The fact that it presents the symplesiomorphic brain pattern observed in earliest Artiodactyla indicates that the cetacean brain derives from a very simple, plesiomorphic brain, with simple neocortical folding pattern, widely exposed midbrain, and concurrent small neocortex expansion. On the other hand, the Indohyus endocast shows characters that also occur in early cetaceans. These include modifications of the olfactory tract with narrow, elongated olfactory bulbs and peduncles, accompanied by a posterior location of the braincase in the cranium. The derived endocranial cast features of Indohyus mainly reflect changes in cranial architecture and these are most probably associated with modifications of the masticatory apparatus and a shift in diet. Indohyus meninges were very thin as in most terrestrial artiodactyls and it had no extensive rostral or lateral retia mirabilia. It however shows a branching pattern of ramification of intraosseous blood sinuses above the cerebellum that might represent the initial development of the caudal venous rete mirabile that would have colonized the endocranial cavity later on, in early archaeocetes.

Comparing N-hexyl cyanoacrylate (Magic Glue) and N-butyl cyanoacrylate (NBCA) for neurovascular embolization using the pressure cooker technique: An experimental study in swine

BackgroundThe pressure cooker (PC) technique uses a second microcatheter to produce a proximal occlusion to prevent the reflux of liquid embolic agent (LEA) injected through a more distal microcatheter, and can be used to treat arteriovenous malformations and dural arteriovenous fistulae. The liquid embolic Magic Glue (MG) (N-hexyl cyanoacrylate (NHCA)) has been introduced as an alternative to N-butyl cyanoacrylate (NBCA). Our goals were to compare the extent of embolization of rete mirabile with or without the PC technique using NBCA or MG, and to compare the proximal occlusions obtained with MG or NBCA while using the PC technique in a renal arterial model. MethodsRete mirabile were embolized with (n = 4) and without (n = 4) the PC technique, using MG (n = 4) or NBCA (n = 4). A renal arterial model was then used to study the characteristics of the MG plug (n = 10) used for the PC technique, and resistance to catheter withdrawal as compared to NBCA (n = 4). Specimens were analyzed macro- and microscopically and compared to angiographic results. ResultsExtent of rete embolization with CYA agents was not significantly greater when using the PC technique. Results were similar with both types of cyanoacrylate (p = 0.657). The force necessary to withdraw the microcatheter was less with MG than with NBCA (p = 0.035). ConclusionMG was similar to NBCA in extent of rete embolization. Less traction force was necessary to withdraw trapped non-detachable microcatheters using MG compared to NBCA.

Anatomical study of the eye arterial blood supply in adult river buffalo (Bubalus bubalis).

Obtaining information about the eye arterial supply in the buffalo can be a criterion for ocular diseases diagnosis and give a morphological basis for even more researches on the related clinical surgery of this animal. The aim of the present study was to describe the course and branches of the arteries supplying the eye in the adult river buffalo (Bubalus bubalis). In this study, the heads of eight buffaloes were prepared from the public slaughterhouse and dissected to study the eye arterial supply. This research results showed that the eye blood supply in the buffalo originates from the external ophthalmic, internal ophthalmic, superficial temporal and malar arteries. The external ophthalmic artery was given rise to branches to take part in the ophthalmic rete mirabile formation and also given off lacrimal, external ethmoidal, supraorbital and ciliary arteries as well as muscular branches to supply the eye ball and extra-ocular muscles. The internal ophthalmic artery was one of the sources of lateral posterior long ciliary artery. The superficial temporal artery was detached off some branches to supply the lateral angle of inferior and superior eyelids as well as lacrimal branch to supply lacrimal gland. The malar artery was originated from the infra-orbital artery and its branches were supplied the medial angle of inferior, superior and third eyelids. There were no obvious differences between buffalo and yak regarding arteries supplying the eyes. However, there were minor differences between buffalo and oxen, sheep and goat and there were obvious differences between buffalo and camel and giraffe.

Ontogeny of regional endothermy in Pacific bluefin tuna (Thunnus orientalis)

Tunas can elevate their red (slow-twitch, oxidative) skeletal muscle, visceral and cranial temperatures significantly above the ambient water temperature (Ta) with the aid of specialized blood vessels (retia mirabilia) that conserve metabolic heat. The ontogeny of this phenomenon, known as regional endothermy, was studied in young [18.5–62.5 cm fork length (FL), 71–5350 g body mass, 2–16 months of age] Pacific bluefin tuna (Thunnus orientalis). Maximal red muscle, visceral and cranial temperatures were measured in parallel with measuring red muscle mass and the size of the red muscle and visceral retia. The maximal thermal excess (maximal tissue temperature – Ta) increased from 1.1 ± 0.3 °C (mean ± SD) to 11.1 ± 3.4 °C in the red muscle, from 0.6 ± 0.3 °C to 3.5 ± 1.4 °C in the viscera and from 0.5 ± 0.4 °C to 2.0 ± 0.6 °C in the cranium in the smallest individuals compared with the largest. Thus, red muscle endothermy was well developed, but visceral and cranial endothermy were still developing, in the largest individuals studied. The scaling coefficients, relative to body mass, for total red muscle mass (0.90 ± 0.03, mean ± SE), red muscle rete (RMR) length (0.84 ± 0.06), maximum number of RMR blood vessel rows (0.43 ± 0.04) and visceral rete cross-sectional area (0.90 ± 0.08), indicated negative allometry for total red muscle mass ( 0.33) and the area of the visceral rete (> 0.67).

Initial Experience in a Pig Model of Robotic-Assisted Intracranial Arteriovenous Malformation (AVM) Embolization.

Robotic assistance for coronary and peripheral vascular pathologies is steadily gaining popularity. However, it has yet to be applied to neurovascular intervention. To establish the feasibility of the CorPath® GRX robotic-assisted platform (Corindus Inc, Waltham, Massachusetts) for intracranial arteriovenous malformation (AVM) embolization. This robotic system was used to embolize intracranial AVMs (n=4) in 2 anesthetized pigs, under controlled conditions appropriate for clinical intervention. Initially, a catheter was manually introduced into the common carotid artery (CCA). Then, the robotic system was used to advance the catheter into the ascending pharyngeal artery (APA) towards the rete mirabilis, which was used as a model for an AVM, using 0.014 in guidewires and 2.4F/1.7F microcatheters. After doing a pre-embolization APA run, which demonstrated good visualization of the rete, dimethyl sulfoxide (DMSO) was instilled into the microcatheter. A negative roadmap was then done, and Onyx was used to embolize the rete. All 4 AVMs were completely obliterated with no complications, including no contrast extravasation, dissection, thrombosis, or other vascular injury. This study is the first to demonstrate the feasibility of a robotic-assisted platform for intracranial AVM embolization.

Molecular cloning, expression and functional analysis of NF-kB1 p105 from sea cucumber Holothuria leucospilota

The nuclear factor-κB (NF-κB) family is evolutionary conserved and plays key roles in the regulation of numerous basic cellular processes. In this study, a sea cucumber Holothuria leucospilota NF-κB1 p105 named HLp105 was first obtained. The full-length cDNA of HLp105 is 6564 bp long, with a 219 bp 5′ untranslated region (UTR), a 2979 bp 3′ UTR, and a 3366 bp open reading frame (ORF) encoding for 1121 amino acids with a deduced molecular weight of 123.92 kDa and an estimated pI of 5.31. HLp105 protein contains the conserved domain RHD, IPT, ANK and DEATH. HLp105 mRNA can be detected in all tissues examined, with the highest level in the intestine, followed by the transverse vessel, rete mirabile, coelomocytes, respiratory tree, bolishiti, cuvierian tubules, body wall, oesophagus and muscle. Challenged by LPS or poly (I:C), the transcription level of HLp105 was apparently up-regulated in the tissues examined. Besides, Over-expression of HLp105 in HEK293T cells, the apoptosis was inhibited, and the cytokines IL-1β and TNF-α were activated. The results are important for better understanding the function of NF-κB1 p105 in sea cucumber and reveal its involvement in immunoreaction.

Liquid embolic agent Fe3O4-EVOH for endovascular arteriovenous malformation embolisation: Preliminary evaluation in an in vivo swine rete mirabile model.

Arteriovenous malformation (AVM) embolisation is in peril after the ARUBA trial. Advancements that are needed to reduce procedural risk are better control and visualisation during micro-catheter injection of liquid embolic material. The injectability, radiographic visualisation, mechanical stability and biocompatibility of the embolic agent Fe3O4-EVOH was evaluated in an in vivo swine AVM model. The swine AVM model is the rete mirabile (RM). Nine swine AVM models were embolised with the embolic agent Fe3O4-EVOH by using a 1.5 F micro-catheter. Procedure times, embolisation success (defined as complete embolisation of the nidus), volume of embolic agent and histopathology were assessed. Six swine underwent embolisation of one side rete, and three underwent embolisation of both sides. We did not experience any technical complication during embolisation of each rete. The micro-catheter was easy to retrieve. Fluoroscopic visualisation of the Fe3O4-EVOH cast was adequate. The mean embolisation time for each RM was 7.5 minutes. The median volume of the embolic agent for each RM was 0.52 mL. At one, four and eight weeks following injection, microscopic and histological analysis demonstrated minimal inflammatory changes in the perivascular tissues and permanent occlusion of the embolised vasculature. Fe3O4-EVOH embolic agent is an effective endovascular occlusion material, providing the initial in vivo characteristics of stability and biocompatibility.

Anatomical reorganization within the hand and forelimb of Perodicticus potto

Historical behavioral accounts note extraordinarily high grip strength in Perodicticus potto. Anatomical analysis of the potto’s hand and forelimb reveal several specializations that may facilitate this enhanced gripping ability, including a specialized vascular bundle (the retia mirabilia) within the wrist, a hyper‐abducted pollex, and a highly reduced second digit. The myological correlates of grip strength (i.e., the contractile potential of the hand and wrist musculature) of P. potto, however, have yet to be quantitatively evaluated. The current study contrasts the myology of the hand and forearm muscles within P. potto to a series of closely‐related strepsirrhines (Nycticebus coucang, Otolemur crassicaudatus, Hapalemur griseus, and Eulemur mongoz), as well as comparing the forearm musculature to a broader (n= 41) primate sample. Despite reports of the potto’s high grip strength, our findings demonstrate relatively below‐average force capacity (relatively low physiological cross‐sectional area) within the digital flexors of this species, which suggests that the gripping ability of this species may be less extraordinary than previously hypothesized. In addition to this observation, we report a number of unusual myological features within the potto, including the largest brachioradialis (an elbow flexor) of any taxon within our sample. Even more surprisingly, we identified an independent extensor indicis within P. potto, despite the vestigial nature of the second digit, and the absence of this muscle within ~25% of other taxa within our sample ‐ all of which possessed a more substantial second digit than the potto. These data underscore the curious nature of the potto’s antebrachial musculature, but suggest that adaptations within the potto’s forelimb may be more related to maximizing endurance grip potential than towards increasing myological force.Support or Funding InformationNational Science Foundation (IOS‐15‐57125 and BCS‐14‐40599)

Intra-arterial in-situ bevacizumab injection effect on angiogenesis. Results on a swine angiogenesis model

Background and purposeIn this study we tested the effect of antiangiogenics on a swine angiogenesis model that shares some brain AVM histological characteristics. The objective was to determine bevacizumab effects on retia volumes and on vessels’ wall. Materials and methodsFifteen pigs were divided into 3 groups: Five animals served as controls (group A), 5 animals underwent endovascular left external and common carotid artery occlusion (group B) and 5 animals underwent the same procedure and had an intra-arterial in-situ injection of bevacizumab (groupC) 2 months after the occlusion. A DSA associated with 3D-rotational angiography was performed at day 0 and at 3 months in all groups in order to measure rete mirabile volumes. The animals were sacrificed at 3 months and the retia were harvested for pathological and immunohistochemistry examinations. ResultsAll VEGF-A receptors were blocked at the site of injection and there was a local enhanced endothelial proliferation and apoptosis. The volume of the retia remained unchanged after the bevacizumab injection. Retia vessels presented comparable media thickness, higher endothelial proliferation and apoptosis after the anti-VEGF injection. ConclusionA single in-situ injection of bevacizumab in this swine angiogenesis model showed no change in retia volume and an extensive blockage of VEGF receptors at the site of injection one month later. Rete mirabile vessels presented comparable media thickness, higher endothelial proliferation and apoptosis after the anti-VEGF injection, suggesting that bevacizumab antiangiogenic effect does not fragilize vessel wall. More studies are needed to confirm these preliminary insights of in-situ antiangiogenic effect on vascular malformations.

Intralobar Pulmonary Sequestration with Rete Mirabile as Part of Its Systemic Artery

Intralobar sequestration (ILS) is a complex lung lesion where part of a lower lobe lacks communication with the tracheobronchial tree and receives an aberrant arterial blood supply from the systemic circulation. That systemic artery is usually large, originating from the thoracic aorta or the abdominal aorta and its upper branches. We describe a case of ILS where a large systemic artery coming up from below the diaphragm is formed by the convergence of many very small serpiginous arteries coming up from the area of the celiac trunk and common hepatic artery: a kind of “rete mirabile”. This peculiar morphology was not described before.

Angiographic study of the transdural collaterals at the anterior cranial fossa in patients with Moyamoya disease.

Unlike its parietal, temporal, and occipital counterparts, the frontal lobe has a broad basal surface directly facing the anterior cranial fossa dura mater which could permit establishment of transdural collaterals (TDCs) with the frontal lobe. Studies on the TDCs from the anterior cranial fossa in moyamoya disease (MMD) are scarce and inadequately investigated. A retrospective study of 100 hemispheres in 50 patients who were diagnosed with MMD by catheter angiography between January 2015 and June 2019 was performed in our institution. TDCs through the anterior ethmoid artery (AEA) or posterior ethmoid artery (PEA) were divided into 3 types respectively based on their respective angioarchitecture. Furthermore, we also studied TDCs to the temporal, parietal, and occipital lobes and collaterals from the posterior circulation to the territory of the anterior cerebral artery. TDCs through the AEA and PEA were identified in 89 (89/100, 89%) and 73 (73/100, 73%) of the hemispheres. The vascularization state of the frontal lobe was good in 89 (89/100, 89%) hemispheres. Rete mirabile and TDCs through the PEA were statistically different among patients with different Suzuki stages. No statistical difference was noted in TDCs through the AEA, frontal TDCs from other sources, and the vascularization state of the frontal lobe with regard to different Suzuki stages. TDCs through the AEA and PEA at the anterior cranial fossa play a very important role in compensating the ischemic frontal lobe. The frontal lobe could be well compensated in most of the patients with TDCs at the anterior cranial fossa.

Neuroendovascular-specific engineering modifications to the CorPath GRX Robotic System.

The aim of this study was to evaluate new, neuroendovascular-specific engineering and software modifications to the CorPath GRX Robotic System for their ability to support safer and more effective cranial neurovascular interventions in a preclinical model. Active device fixation (ADF) control software, permitting automated manipulation of the guidewire relative to the microcatheter, and a modified drive cassette suitable for neuroendovascular instruments were the respective software and hardware modifications to the current CorPath GRX robot, which was cleared by the FDA for percutaneous coronary and peripheral vascular intervention. The authors then trialed the modified system in a live porcine model with simulated neuroendovascular pathology. Femoral access through the aortic arch to the common carotid artery was accomplished manually (without robotic assistance), and the remaining endovascular procedures were performed with robotic assistance. The system was tested for the enhanced ability to navigate and manipulate neurovascular-specific guidewires and microcatheters. The authors specifically evaluated the movement of the wire forward and backward during the advancement of the microcatheter. Navigation of the rete mirabile and an induced aneurysm within the common carotid artery were successful. The active device fixation feature enabled independent advancement and retraction of the guidewire and working device relative to the microcatheter. When ADF was inactive, the mean forward motion of the guidewire was 5 mm and backward motion was 0 mm. When ADF was active, the mean forward motion of the guidewire was 0 mm and backward motion was 1.5 mm. The modifications made to the robotic cassette enabled the system to successfully manipulate the microcatheter and guidewire safely and in a manner more suited to neuroendovascular procedures than before. There were no occurrences of dissection, extravasation, or thrombosis. The robotic system was originally designed to navigate and manipulate devices for cardiac and peripheral vascular intervention. The current modifications described here improved its utility for the more delicate and tortuous neurovascular environment. This will set the stage for the development of a neurovascular-specific robot.