Carotid Rete Mirabile Research Articles

A Case of Carotid Rete Mirabile Associated with Basilar Tip Aneurysm

Carotid rete mirabile (CRM) is a rare condition consisting of a physiological network between the external and internal carotid arteries in lower vertebrates. Only a few cases have been reported in humans presenting as hemorrhagic or ischemic cerebrovascular disorder. We present a case of CRM presenting as an aneurysmal subarachnoid hemorrhage and discuss the embryologic, anatomic, hemodynamic and clinical significance of this rare entity.

Histomorfologia do gânglio de Gasser, da rete mirabile carotídea e da hipófise de bovinos: estudo de 199 casos

O complexo heterogêneo de tecidos formado pelo gânglio de Gasser, rete mirabile carotídea e hipófise (GRH) de 199 bovinos foram macro e microscopicamente avaliados. Vinte e um GRH eram de casos confirmados de raiva, 19 com diagnóstico de meningoencefalite por herpesvírus bovino-5 (BoHV-5), 11 casos de febre catarral maligna (FCM), 7 tinham abscesso de pituitária, 17 apresentaram lesões de encefalopatia hepática (status spongiosus) atribuído à fibrose crônica por intoxicação por Senecio sp; e os 124 GRH restantes eram provenientes de bovinos que não apresentaram sinais neurológicos e que morreram ou foram eutanasiados por causas diversas. Nenhuma alteração histológica significativa foi observada no GRH dos 124 bovinos que não tinham sinais neurológicos, nos 17 bovinos com encefalopatia hepática, nem nos 19 bovinos afetados por meningoencefalite por BoHV-5. Alterações inflamatórias foram encontradas em 20 dos 21 casos de raiva e consistiam de proliferação de células satélites, nódulos gliais e infiltrado linfo-plasmocitário; alterações degenerativas incluíam cromatólise central, vacuolização neuronal e necrose neuronal com neuronofagia. Corpúsculos de inclusão eosinofílicos intracitoplasmáticos (de Negri) foram encontrados em 19 dos 21 casos de raiva; neurite do nervo trigêmeo em 11 casos e neuroipofisite em 4 casos. O complexo GRH de 9 de 11 casos de FCM apresentava arterite necrosante, que afetava as artérias da rete mirabile carotídea. Em 7 dos 199 GRH examinados havia abscessos de pituitária caracterizados por agregados de neutrófilos e detritos celulares circundados por infiltrado mononuclear e cápsula fibrosa. Vários achados incidentais foram observados nos 199 GRH examinados histologicamente e não foram correlacionados com alterações ligadas a doenças. Estes incluíam cistos na cavidade hipofisária, agregados de fibrina e neutrófilos no seio cavernoso da rete mirabile carotídea, leve aumento do número de células satélites ao redor dos neurônios do gânglio de Gasser e ocasional vacuolização e lipofuscinose neuronal. O exame histológico do complexo GRH é uma ferramenta importante e confiável no diagnóstico das principais encefalites em bovinos no Brasil.

Carotid Rete Mirabile Associated With Subarachnoid Hemorrhage-Case Report-

A 47-year-old man presented with carotid rete mirabile manifesting as subarachnoid hemorrhage (SAH). Computed tomography showed SAH, and angiography disclosed an abnormal vascular network around the petrous and cavernous portions of the internal carotid artery. Single photon emission computed tomography (SPECT) with technetium-99m methyl cysteinate dimer revealed reduced regional cerebral blood flow (CBF). Twelve months later, he was leading a normal life without neurological problems, hemorrhage, or ischemic manifestations. SPECT with iodine-123 N-isopropyl-p-iodoamphetamine and the acetazolamide challenge test showed the CBF had normalized.

Bilateral segmental regression of the carotid and vertebral arteries with rete compensation in a Western patient

We report a case of symptomatic symmetrical, bilateral absence of the cavernous internal carotid (ICA) and transdural vertebral artery (VA) segments with formation of a rete mirabile. There have been similar reports in Asian patients; ours is the first in the Western population. A 29- year-old woman presented with recurrent temporary blindness and an episode of minor subarachnoid haemorrhage. Angiography demonstrated absence of the C5 and C6 segments of the ICA and the C1/2 segments of the VA bilaterally, with typical carotid rete mirabile formation to reconstitute the distal flow. Comparative anatomy and embryology show retia in several species and point to their secondary origin. The anomalies of the ICA cannot be called agenesis but rather absence since they are likely to result from perinatal disappearance of the artery rather its failure to develop.

Pseudoxanthoma elasticum with carotid rete mirabile

We describe a case of Pseudoxanthoma elasticum (PXE) in a 14-year-old girl. This case is especially rare because of its association with carotid rete mirabile (CRM). Only three cases have been reported previously in the literature. Although the relation between P. elasticum and carotid rete mirabile is unclear, both disorders are believed to be major risk factors for cerebrovascular disease.

Use of the swine carotid rete mirabile in experimental interventional neuroradiology: A renew of normal and applied anatomy

Use of the swine carotid rete mirabile in experimental interventional neuroradiology: A renew of normal and applied anatomy

The structural organization and adrenergic innervation of the carotid arterial system of the giraffe (Giraffa camelopardalis)

The sympathetic innervation of the giraffe (Giraffa camelopardalis) carotid arterial system is described in this study using the sucrose-potassium phosphate-glyoxylic acid (SPG) method. The brachiocephalic and bicarotid trunks showed a paucity of sympathetic innervation. Smooth muscle nests observed in the outer layers of the tunica media in these arteries revealed a rich network of sympathetic nerve fibres. The common carotid artery showed numerous sympathetic nerve fibres particularly in the outer muscular zone of the tunica media. The internal maxillary, ramus anastomoticus, and arteria anastomotica also revealed a rich sympathetic innervation and a deep penetration of the nerve fibres into the tunica media. It is suggested that the rich sympathetic innervation of the giraffe carotid arteries maintains a basal tonic state in the smooth muscle in the tunica media. This, in turn, may enable the animal to maintain a relatively high rate of blood flow in the carotid arteries in diastole despite the pressure run-off. It is further suggested that the muscular structure and dense sympathetic innervation of the internal maxillary and its branches to the carotid rete mirabile provide the animal with an array of mechanisms to modulate its cranial circulation particularly when it bends its head to drink.

Structure and sympathetic innervation of the intracranial arteries in the giraffe (Giraffa camelopardalis)

Fluorescence histochemistry discloses that the carotid rete mirabile in the giraffe has a poor sympathetic innervation. In contrast, the efferent artery of the rete (internal carotid artery) and the cerebral arteries show moderate sympathetic innervation. A certain degree of regional variability was noted in which the rostral arteries (anterior and middle cerebral) receive more sympathetic nerves than the caudal (posterior communicating and basilar) arteries. The sympathetic nerves on the giraffe cerebral vessels may constitute part of a host of mechanisms by which regional blood flow to the brain is regulated. Conversely, the paucity of sympathetic innervation of the carotid rete mirabile may indicate that this structure does not play an active role in vasoconstrictor responses during postural changes of the head.

Elaeophora schneideri in Moose (Alces alces) from Colorado

Two adult moose (Alces alces) from Colorado (USA) were naturally infected with Elaeophora schneideri. Both animals had patent infections indicating that moose may serve as definitive hosts. Gross and histological lesions were characterized by fibromuscular intimal proliferation within the carotid arteries and rete mirabile cerebri. This is the first report of Elaeophora schneideri in moose from Colorado.

The ferret as an animal model in cerebrovascular research.

Clinical and pathologic observations have suggested analogies between the developing nervous system of ferrets (Mustela putorius furo) and those of more traditional animal models employed in stroke research. Experimental work has demonstrated advantages of the ferret as a model of visual development. We performed in vivo cerebral angiography and postmortem neurovascular dissection of latex-injected specimens of adult ferrets. The great vessels include a cervical arterial trunk that gives rise to both carotid arteries. The anatomy of the cranial arteries is similar to that of rabbits. No carotid rete mirabile is present. There are no intracranial anastomoses between the external and internal carotid systems. We present in vivo cerebral angiograms with pathologic correlation that demonstrate that ferrets may provide the same anatomic advantages as a rabbit model for the experimental study of cerebrovascular disease, with the additional advantage of a long extracranial cervical segment of the carotid artery, affording easier access to the intracranial vasculature.

Mechanics of arteries forming the carotid rete of goat and cattle

To determine the mechanics of arteries forming the carotid rete mirabile of goat and cattle, the wall tension-circumference length relationship was recorded isometrically in isolated retial arteries of 350–600 μm in external diameter under relaxed and potassium-activated conditions. The results are compared to those of pial arteries of similar size. In relaxed retial and cerebral vessels, tension-length relationship had nonlinear characteristics and the incremental elastic modulus rose as the circumference length increased, the modulus being lower in retial than in pial arteries. However, the stiffness of the artery considered as a whole (stiffness parameter β) was similar in the two types of vessels. In activated arteries, force development was a function of length and the magnitude of the response increased until an optimal length was reached after which the response decreased with further stretch. In all stretches studied the developed force was much lower in retial arteries. The calculated active stress at the various lengths was also smaller in retial than in cerebral arteries and the maximum active stress for retial arteries was about 30–50% of that for cerebral arteries. Therefore, the passive mechanical properties of retial arteries closely resemble those of cerebral arteries but retial arteries have a small contractility. This suggests that the carotid rete mirabile of Artiodactyla has a minor role in actively controlling blood supply to the brain. Comments on the hemodynamic significance of the carotid rete are included.

The Control of Panting and Sweating in the Black Bedouin Goat: A Comparison of Two Modes of Imposing a Heat Load

The black Bedouin goat uses both panting and sweating as modes of evaporative heat loss. The control of panting and sweating was studied by examining the body temperature distribution under heat loads which produced equivalent levels of evaporative heat loss, namely, solar radiation and high air temperature conditions. Heat exposure induced by high air temperature resulted in a proportionally greater respiratory water loss than did outdoor exposure to solar radiation; the greater respiratory cooling was related to higher hypothalamic and arterial temperatures but lower skin temperatures. However, solar radiation resulted in a higher temperature of the skin under the irradiated fur, and this was associated with a greater cutaneous moisture loss. Thus, the mode of evaporation was concluded to be appropriate to the thermal stimulus: higher nasal temperature resulted in a predominant panting response, and high skin temperature invoked greater sweating. The gradient between arterial and hypothalamic temperature was not necessarily correlated with panting, providing evidence that blood flow through the countercurrent heat exchanger, the carotid rete mirabile, was utilized only when hypothalamic temperature rose above a critical level.

Pseudoxanthoma elasticum associated with carotid rete mirabile. Case report.

PSEUDOXANTHOMA ELASTICUM ASSOCIATED WITH CAROTID RETE MIRABILE CASE REPORTANDREW H. KOO, M.D. and THOMAS H. NEWTON, M.D.Audio Available | Share

Pseudoxanthoma elasticum. Association with bilateral carotid rete mirabile and unilateral carotid-cavernous sinus fistula.

Pseudoxanthoma elasticum in a 20-year-old man was complicated by right-sided proptosis, conjunctival vascular dilation, and subretinal bleeding from preexisting angioid streaks. Angiography showed multiple anomalies of major systemic arteries, including bilateral carotid rete mirabile and right carotid-cavernous sinus fistula. Electrothrombosis of the right cavernous sinus obliterated the fistula, restored cerebral perfusion by the right carotid system, and promoted prompt resolution of the presenting signs.

Bilateral carotid vertebrobasilar rete mirabile. Case report.

✓ A case of bilateral internal carotid artery hypoplasia with bilateral carotid rete mirabile is described in which the intracranial circulation was fed predominantly by external carotid anastomosis, the vertebrobasilar system, and the internal carotid system.

Carotid rete mirabile — An unusual example associated with diffuse bilateral cerebral telangiectasia

The authors report a case of bilateral internal carotid occlusive disease in a 10 year old girl exhibiting telangiectatic anastomoses between the external carotid system and the leptomeningeal vessels on the surface of the brain. It would appear that this patient is an example of an unusual form of progressive cerebral arterial occlusion.

Pulse attenuation and countercurrent heat exchange in the internal spermatic artery of some Australian marsupials.

The unusual complexity of the testicular blood vessels of eutherian mammals has been shown to have haemodynamic and thermoregulatory significance. The pulse wave of pressure passing down the long, coiled internal spermatic artery of the ram (Waites & Moule, 1960), dog (Blombery, Gow & Waites, unpublished observations) and rat (Setchell, 1969) is attenuated to a small oscillation, but mean blood pressure is only marginally reduced. A similar pressure-damping action was described for the carotid rete mirabile of the dolphin (Nagel, Morgane, McFarland & Galliano, 1968). There is also plentiful evidence for countercurrent heat exchange between neighbouring arteries and veins (see Waites, 1969). As the spermatic veins closely surround the internal spermatic artery, Harrison & Weiner (1949) proposed that heat exchange was occurring between the counterflowing blood streams. This was confirmed by measuring the thermal gradients in the testicular circulation of dogs (Dahl & Herrick, 1959) and rams (Waites & Moule, 1961). The internal spermatic artery of most marsupials divides into many parallel branches which intermingle in the spermatic cord with a similar number of parallel veins (Harrison, 1948, 1949, 1951; Barnett & Brazenor, 1958). One might expect that this different way of increasing vascular surface area, by branching rather than elongation, would have similar haemodynamic and thermal consequences, but experiments to examine this have apparently not been performed. Six adult tammar wallabies (Macropus eugenii Desmarest) weighing between 5-4 and 9 kg, and two adult red kangaroos (Megaleia rufa Desmarest), weighing 36 and 42 kg, were anaesthetized with pentobarbitone sodium. Rectal tempera¬ ture, recorded with a thermocouple, was maintained with an electric blanket at the values recorded immediately after anaesthesia. The testes were exposed and copper constantan thermocouples (45 S.W.G. mounted in the tips of 25 S.W.G. hypodermic needles) were immediately inserted into the testis, and into a testicular vein and a testicular artery on the surface of one testis. Two to four arteries run along the epididymal margin and a similar number of veins along the free margin (Setchell, 1969). It was thus possible to insert the needle into one vessel and push it as far as a junction with another so that blood was flowing past the site of measurement. The arterial thermocouple was within

Functions of the mammalian carotid rete mirabile.

ALTHOUGH a carotid rete mirabile is present in many mammals, notably the artiodactyla, its function is uncertain. Many workers have suggested that the rete may regulate the cerebral blood-flow1,2, but emphasis has usually been laid on its effect on the arteries rather than the veins. However, an alternative possibility is that the rete is concerned primarily with assisting the venous return from the interior of the cranium, which is especially liable to be embarrassed in animals that feed with the head dependent. Enhancement of the blood-flow in veins is known to be a function of certain retia mirabilia elsewhere3.