Carotid and vertebral rete mirabile in man presenting with intraparenchymal hemorrhage: a case report

Revised concept of rete-like collateral formation: Rete mirabile does not exist in humans

The carotid rete is a physiological network between the external and internal carotid arteries (ICA) in lower vertebrates. However, true carotid rete does not exist in humans. This review aimed to contrast the physiological function of human "rete-like collaterals" with that of lower vertebrate "rete mirabile". An explanation for the development of rete-like collaterals in human intracranial arteries was also discussed. The rete mirabile (carotid, vertebral, spinal, and thoracic) in lower vertebrates has a specific physiological role and does not form vasculature for the same purpose in humans. Therefore, the term "rete mirabile" should not be used for cases reported in humans. Instead, "rete-like collaterals" is preferred. In the literature, rete-like or arterial anastomosis was observed in the ICA cavernous portion and the intradural arteries. Based on the hypothesis of the segmental concept, it applies to the ICA and intracranial arteries. Whether in the ICA, middle cerebral artery, posterior cerebral artery, or posterior inferior cerebellar artery, the segmental concept is the same and should be considered to have formed secondary collaterals after segmental regress or dysgenesis of affected arteries. Summarily, the significance of this review lies in its reevaluation of vascular structures previously described as "carotid rete" in humans to a true and preferred term, "rete-like collaterals". It also provides insights into the historical context and potential genetic factors associated with the formation of arteries in humans, contributing to a better understanding of human vascular anatomy.

Unilateral cervical and petrosal segment agenesis of the internal carotid artery with rete mirabile

The carotid rete mirabile (RM) is a physiological network between the internal and external carotid arterial systems. In this paper, an extremely rare case is presented, in which internal-external carotid artery anastomoses and a dilated ascending pharyngeal artery, due to unilateral agenesis of the cervical and petrous segments of the internal carotid artery (ICA), is presented.

Rete mirabile of the ICA: Report of three cases

Carotid rete mirabile is an arterial meshwork, occurring at the cavernous portion of the internal carotid artery (ICA). Rete mirabile in humans is not present during normal development of the intracranial circulation and hence is considered as a collateral pathway that develops as a consequence of segmental agenesis of the ICA. We report three cases of this rare entity encountered at our institute.

Rete mirabile associated with pial arteriovenous fistula: imaging features with literature review

A rete mirabile is a vascular network of intercommunicating small arteries or arterioles that replace the definitive adult artery supplying the brain. It supplies the brain in lower mammals but is not seen in normal human embryological development. A 26-year-old man presented with worsening tinnitus that was interfering with his sleep. On CT and digital subtraction angiography he was found to have a temporal lobe pial arteriovenous fistula with bilateral carotid and vertebral rete mirabile. The patient was offered open surgical and endovascular treatment options for pial arteriovenous fistula but he refused both and opted for conservative medical management. At 6-month follow-up he continued to have pulsatile tinnitus but was otherwise neurologically normal. We present the first described association of rete mirabile with pial arteriovenous fistula and discuss its clinical presentation and imaging features, with a review of the literature for bilateral carotid and vertebral rete mirabile.

Bilateral segmental agenesis of carotid and vertebral arteries with rete mirabile and the prominent anterior and posterior spinal arteries as compensations

Agenesis of carotid or vertebrobasilar arteries with rete formation is rare. The anterior spinal artery or posterior spinal arteries supplying the posterior circulation with steno-occlusion or agenesis of bilateral vertebral arteries is also uncommon. Here, we describe a very rare case of concomitant segmental agenesis of bilateral carotid and vertebral arteries with collateral compensations from the prominent anterior spinal artery and posterior spinal arteries, as well as some transdural arterial networks which were considered a rete mirabile. We discuss its embryological and anatomic significance.

Bilateral carotid and vertebral rete mirabile presenting with a prominent anterior spinal artery mimicking a spinal dural AV fistula at MRI

Bilateral carotid and vertebral rete mirabile (CVRM) is a very rare condition. We report a new case of CVRM initially detected by magnetic resonance imaging (MRI) of the cervical spine. MRI demonstrated tortuous vascular signal voids limited to the anterior cerebrospinal fluid space mimicking spinal dural arteriovenous fistula. A diagnosis of CVRM was confirmed on the basis of angiographic findings of rete formation associated with bilateral aplasia of the cavernous internal carotid and vertebral arteries without abnormal arteriovenous connection.

Asymptomatic carotid rete mirabile and contralateral carotid agenesis: a case report

Carotid rete mirabile (CRM) is a physiological network between the external carotid artery (ECA) and internal carotid artery (ICA) in lower mammals. It is a transdural arterial network centered at the parasellar area, in anatomical localization of intracavernous or petrous segment of ICA, associated with hypoplasia or absence of the cervical or petrous segment of ICA. It clinically presents as hemorrhagic or ischemic cerebrovascular disorder. Carotid rete mirabile have an angiographic frequency of 0.01%. The authors present a new case of right ICA agenesis supported by primary collateral channels associated with left hypoplasic ICA and CRM. It is an unusual entity and we highlight the role of CRM in cerebral hemodynamic in this asymptomatic vascular patient. Our aim is detail the angiographic features and diagnosis criteria of CRM.

A new pattern of arterial rete compensation of segmental basilar agenesis associated with carotid retia mirabilia: a case report (2010: 1b)

The carotid rete mirabile is a transdural arterial network centered at the parasellar area, in place of the intracavernous internal carotid artery (ICA), associated with hypoplasia or absence of the cervical and petrous ICA. Rare cases of vertebral rete mirabile associated with segmental agenesis of transdural vertebral arteries have been reported before. The authors present a new case of carotid rete mirabilia associated with segmental basilar agenesis compensated by a previously unknown pattern of arterial rete. Collateral flow, its efficacy and differential diagnosis are discussed.