[Advances in clinical anatomy of the transnasal approaches to the parapharyngeal segment of the internal carotid artery].

The intracranial segment of the internal carotid artery located inside the skeleton structure of skull base or inside the skull has clear anatomical landmarks and fixed anatomical structure. However, the parapharyngeal segment of the internal carotid artery located outside the cranial is surrounded by soft tissues, lacks clear and recognizable anatomical landmarks and sometimes has anatomical variation, which is closely related to transnasal endoscopic surgery. Intraoperative accidental injury can lead to serious complications or even death. Currently, clinical anatomical studies related to the parapharyngeal segment of the internal carotid artery under transnasal endoscopic surgery mainly focus on its anatomical variation and anatomical landmarks. This article reviews on these two aspects in order to provide anatomical reference for surgeons to reduce surgical risks during transnasal endoscopic surgery.

Synchronous subarachnoid haemorrhage and ischaemic stroke as a result of complete internal carotid artery occlusion.

A previously healthy man in his 60s presents with a one-day history of insidious onset headache and 'walking into doors'. He reported transient right arm pain and tingling but no weakness. A CT brain showed a right middle cerebral artery (MCA) infarct as well as a synchronous right frontal lobe convexal subarachnoid haemorrhage (cSAH). An arch to vertex CT angiogram demonstrated right MCA occlusion and complete right internal carotid artery (ICA) occlusion from its origin. Reconstitution of flow was seen within the distal right ICA at the level of the distal foramen lacerum. A repeat CT of the brain after one week showed a stable appearance of the bleeding and infarct. He was commenced on antiplatelet therapy for the treatment of the ischaemic stroke as well as secondary prevention.This is a rare case of synchronous right MCA infarct as well as a right frontal cSAH secondary to ipsilateral carotid artery occlusion.

Facilitating Repeat Intracarotid Injections in Mouse Models by a Novel Injection Site Repair Technique.

Given recent advances in the delivery of novel antitumor therapeutics using endovascular selective intraarterial delivery methods in neuro-oncology, there is an urgent need to develop methods for intracarotid injections in mouse models, including methods to repair the carotid artery in mice after injection to allow for subsequent injections. We developed a method of intracarotid injection in a mouse model to deliver therapeutics into the internal carotid artery (ICA) with two alternative procedures. During injection, the needle is inserted into the common carotid artery (CCA) after tying a suture around the external carotid artery (ECA) and injected therapeutics are delivered into the ICA. Following injection, the common carotid artery (CCA) can be ligated, which limits the number of intracarotid injections to one. The alternative procedure described in this article includes a modification where intracarotid artery injection is followed by injection site repair of the CCA, which restores blood flow within the CCA and avoids the complication of cerebral ischemia seen in some mouse models. We also compared the delivery of bone marrow-derived human mesenchymal stem cells (BM-hMSCs) to intracranial tumors when delivered through intracarotid injection with and without injection site repair following the injection. Delivery of BM-hMSCs does not differ significantly between the methods. Our results demonstrate that injection site repair of the CCA allows for repeat injections through the same artery and does not impair the delivery and distribution of injected material, thus providing a model with greater flexibility that more closely emulates intracarotid injection in humans.

Beware of epistaxis: fatal pseudoaneurysm rupture 30 years after treatment of acromegaly.

We present a fatal complication of treatment in a patient with early-onset acromegaly, treated with two transsphenoidal operations, radiotherapy, radiosurgery and pegvisomant. He was diagnosed in his 30s, and controlled from his 40s, with stable residual tumour within the left cavernous sinus. In his 60s, 30 years after surgery/radiotherapy and 14 years after radiosurgery, he developed recurrent episodes of mild epistaxis. A week later, he presented at his local hospital's emergency department with severe epistaxis and altered consciousness. He was diagnosed with a ruptured internal carotid artery (ICA) pseudoaneurysm, but unfortunately died before treatment could be attempted.ICA pseudoaneurysms are rare complications of surgery or radiotherapy and can present with several years of delay, often with epistaxis. This case highlights the importance of life-long monitoring in patients with previous pituitary interventions and early recognition of epistaxis as a herald sign of a potentially catastrophic event, thus leading to timely treatment.

Middle Cerebral Artery Ischemic Complications After Flow Diverter Deployment from Internal Carotid Artery Extending into M1 Segment.

AIM: To gain a better understanding of ischemia risk related to in-stent stenosis (ISS) or in-stent thrombosis (IST) of the middle cerebral artery (MCA) and lenticulostriate arteries after flow-diverting devices (FDD) deployment from the internal carotid artery (ICA) to proximal middle cerebral artery (M1). MATERIAL AND METHODS: Using data from a prospectively maintained database, we retrospectively evaluated patients who were treated with FDD between January 2015 and 2020 at a single academic center. Only patients with unruptured ICA aneurysms where the FDD was extended into M1 were included. RESULTS: In total, 89 patients with 94 ICA aneurysms were treated with FDD. A total of 34 patients with 36 aneurysms had FDD extending into M1. Of the 34 patients, four experienced MCA, and lenticulostriate territory ischemia. Three patients had in-stent thrombosis (IST), and one patient had severe in-stent stenosis (ISS). The overall ischemic complication rate was 17.6%, which resulted in a permanent neurological deficit in 11.7% of the patients. CONCLUSION: If the distance of the distal neck of the aneurysm to the ICA terminus (ICAT) is ≤5 mm, or if the aneurysm is located directly at the ICAT, FDD should be considered only as a last option when other treatment modalities are not suitable. In addition, in the treatment of distal ICA aneurysms, extra effort should be exerted during the procedure to deploy the FDD without extending into M1. However, when traditional microsurgical clipping and other endovascular procedures are not suitable, the use of FDD is effective in terms of high aneurysm occlusion rates and preventing aneurysm rupture.

[Clinical anatomy of the Bernasconi-Cassinari artery]. / Klinicheskaya anatomiya arterii Bernaskoni­Kassinari.

The article provides a comprehensive overview of the Bernasconi-Cassinari's artery (marginal tentorial branch of internal carotid artery, r. marginalis tentorii a. carotis internae). It includes information on the history of its discovery, anatomical features, and topography. The interrelation between the anatomical features of this artery and the presence of neurological pathology in patients is discussed, along with neurosurgical treatment methodologies.

Case of giant juvenile angiofibroma resected by external incision with temporary double balloon occlusion of the internal carotid artery by intraoperative endovascular treatment.

We report the first case of a juvenile nasal angiofibroma (JNA) fed by multiple arteries from the internal carotid artery (ICA), removed without complications by temporarily blocking the ICA with two balloons. An early adolescent with JNA underwent preoperative embolisation of feeding arteries arising from the external carotid artery (ECA) (University of Pittsburgh Medical Centre classification IV). Endoscopic resection was attempted once but discontinued due to massive bleeding (7000 mL). 17 months later, the JNA had grown to fill both nasal cavities. Repeated preoperative embolisation of the feeders from the ECA was performed, followed by surgery combined with endoscopic and external incision. Intraoperatively, two balloons were inserted into the right ICA, which were inflated at the proximal and distal sites of the feeder vessels to cut-off blood flow to the tumour. The tumour was almost completely resected with 6270 mL of blood loss and no postoperative neurological deterioration.

Splice implantation of multiple drug-eluting stents for tandem severe stenosis of the internal carotid artery: A case report.

RATIONALE: Severe stenosis of the internal carotid artery tandem affects the blood supply to the brain and threatens human life, which can be solved by interventional procedures. PATIENT CONCERNS: A 64-year-old male patient presented with a sudden onset of dizziness, palpitation, numbness, and weakness of the limbs. Imaging studies suggested multiple tandem severe stenoses from the left internal carotid artery contrast C2 to C4. DIAGNOSIS: Severe stenosis of the left internal carotid tandem. INTERVENTIONS: Multiple drug-eluting stent splicing and implantation were performed. OUTCOMES: The left internal carotid artery stenosis was released, intracranial vascular filling was significantly improved, and the patient recovered well. LESSONS: Interventional implantation of multiple drug-eluting stents relieves tandem severe stenosis of the internal carotid artery, with a wide range of applicability, high safety profile, and rapid postoperative recovery compared with endothelial debridement procedures.

Feasibility and efficiency of a new classification based on high-resolution MRI for carotid artery pseudo-occlusion and occlusion: Hybrid revascularization pilot study.

BACKGROUND AND PURPOSE: Studies on changes in the distal internal carotid artery based on high resolution magnetic resonance imaging (HRMRI) are scarce. Herein, we propose a histological classification system for patients with carotid artery pseudo-occlusion or occlusion based on preoperative HRMRI, for which we evaluated the feasibility and clinical implications. MATERIALS AND METHODS: From January 2017 to June 2021, 40 patients with Doppler ultrasound, CTA or MRA suggesting carotid artery occlusion were enrolled in this study. A new classification system based on HRMRI was established and subsequently verified by postoperative specimens. We recorded and analyzed patient characteristics, HRMRI data, recanalization rate, requirements of additional endovascular procedures, complications, and outcomes. RESULTS: Four histological classifications (type Ⅰ-Ⅳ) were identified. According to our classification system, 20 patients (50.00%) were type I, nine (22.50%) were type II, 7 (17.50%) were type III, and four (10.00%) were type Ⅳ. The success rate of recanalization was 88.89% (32/36) in type I-III patients. Four (44.44%) type Ⅱ patients and five (71.43%) type Ⅲ patients suffered from intraoperative dissection. CONCLUSION: Patients identified as types I (pseudo-occlusion) and II (thrombotic-occlusion) were able to be treated via hybrid revascularization with relatively low risk, while patients identified as type III (fibrous-occlusion) required more careful treatment. Recanalization is not suitable for patients identified as type Ⅳ. Our proposed classification system based on HRMRI data can be used as an adjunctive guide to predict the technical feasibility and success of revascularization via a hybrid technique.

[Pathological tortuosity of intracranial arteries (pure arterial malformation) - diagnosis and management tactics]. / Patologicheskaya izvitost' intrakranial'nykh arterii (arterial'naya mal'formatsiya) ­ diagnostika i taktika vedeniya.

BACKGROUND: Tortuosity of intracranial arteries is rare and usually mistaken for arteriovenous malformations. In the world literature, the term «pure arterial malformations¼ is used to refer to this disease. OBJECTIVE: To summarize the experience of the Burdenko Neurosurgery Center on diagnosis of intracranial artery tortuosity, management and treatment of these patients, as well as to review appropriate literature data. MATERIAL AND METHODS: Tortuosity of intracranial arteries was detected in 11 patients (8 women and 3 men) aged 7-48 years who underwent outpatient or inpatient examination and treatment at the Burdenko Neurosurgery Center between 2009 and 2022. We analyzed angiographic, clinical and follow-up data of these patients, as well as appropriate literature data. RESULTS: According to angiography data, all patients had moderate dilatation, elongation and tortuosity of intracranial arteries without signs of arteriovenous shunting. The most common finding was tortuosity of several segments of internal carotid artery (5 cases). Lesion of PCA, PComA, MCA and ACA was less common. In 7 cases, the walls of the deformed vessels had calcified zones. In two cases, there were saccular aneurysms in the walls of the tortuous vessels. In one case, tortuosity was combined with kinking of the left subclavian artery, in another one - tortuosity of C1 segment of the right ICA. No patient had specific clinical manifestations. The follow-up period was 1-10 years in 7 patients. There were no changes in structure of tortuosity or appearance of new aneurysms. CONCLUSION: Tortuosity of intracranial arteries is an extremely rare disease with the highest incidence in young women. This abnormality has no specific clinical manifestations and does not require surgical or conservative treatment. Tortuosity of intracranial arteries should be differentiated from arterial dolichoectasia, fusiform aneurysms and AVMs.

Can Internal Carotid Arteries Be Used for Noninvasive Quantification of Brain PET Studies?

Because of the limited axial field of view of conventional PET scanners, the internal carotid arteries are commonly used to obtain an image-derived input function (IDIF) in quantitative brain PET. However, time-activity curves extracted from the internal carotids are prone to partial-volume effects due to the limited PET resolution. This study aimed to assess the use of the internal carotids for quantifying brain glucose metabolism before and after partial-volume correction. Methods: Dynamic [18F]FDG images were acquired on a 106-cm-long PET scanner, and quantification was performed with a 2-tissue-compartment model and Patlak analysis using an IDIF extracted from the internal carotids. An IDIF extracted from the ascending aorta was used as ground truth. Results: The internal carotid IDIF underestimated the area under the curve by 37% compared with the ascending aorta IDIF, leading to Ki values approximately 17% higher. After partial-volume correction, the mean relative Ki differences calculated with the ascending aorta and internal carotid IDIFs dropped to 7.5% and 0.05%, when using a 2-tissue-compartment model and Patlak analysis, respectively. However, microparameters (K 1, k 2, k 3) derived from the corrected internal carotid curve differed significantly from those obtained using the ascending aorta. Conclusion: These results suggest that partial-volume-corrected internal carotids may be used to estimate Ki but not kinetic microparameters. Further validation in a larger patient cohort with more variable kinetics is needed for more definitive conclusions.

Increased Intracranial Arterial Pulsatility and Microvascular Brain Damage in Pseudoxanthoma Elasticum.

BACKGROUND AND PURPOSE: Carotid siphon calcification might contribute to the high prevalence of cerebrovascular disease in pseudoxanthoma elasticum through increased arterial flow pulsatility. This study aimed to compare intracranial artery flow pulsatility, brain volumes, and small-vessel disease markers between patients with pseudoxanthoma elasticum and controls and the association between arterial calcification and pulsatility in pseudoxanthoma elasticum. MATERIALS AND METHODS: Fifty patients with pseudoxanthoma elasticum and 40 age- and sex-matched controls underwent 3T MR imaging, including 2D phase-contrast acquisitions for flow pulsatility in the assessment of ICA and MCA and FLAIR acquisitions for brain volumes, white matter lesions, and infarctions. All patients with pseudoxanthoma elasticum underwent CT scanning to measure siphon calcification. Flow pulsatility (2D phase-contrast), brain volumes, white matter lesions, and infarctions (3D T1 and 3D T2 FLAIR) were compared between patients and controls. The association between siphon calcification and pulsatility in pseudoxanthoma elasticum was tested with linear regression models. RESULTS: Patients with pseudoxanthoma elasticum (mean age, 57 [SD, 12] years; 24 men) had significantly higher pulsatility indexes (1.05; range, 0.94-1.21 versus 0.94; range, 0.82-1.04; P = .02), lower mean GM volumes (597 [SD, 53] mL versus 632 [SD, 53] mL; P < .01), more white matter lesions (2.6; range, 0.5-7.5 versus 1.1; range, 0.5-2.4) mL; P = .05), and more lacunar infarctions (64 versus 8, P = .04) than controls (mean age, 58 [SD, 11] years; 20 men). Carotid siphon calcification was associated with higher pulsatility indexes in patients with pseudoxanthoma elasticum (ß = 0.10; 95% CI, 0.01-0.18). CONCLUSIONS: Patients with pseudoxanthoma elasticum have increased intracranial artery flow pulsatility and measures of small-vessel disease. Carotid siphon calcification might underlie the high prevalence of cerebrovascular disease in pseudoxanthoma elasticum.

Composition of encephalic arteries and origin of the basilar artery are different between vertebrates.

Intracranial arterial anatomy is lacking for most mammalian and non-mammalian model species, especially concerning the origin of the basilar artery (BA). Enhancing the knowledge of this anatomy can improve animal models and help understanding anatomical variations in humans. We have studied encephalic arteries in three different species of birds and eight different species of mammals using formalin-fixed brains injected with arterial red latex. Our results and literature analysis indicate that, for all vertebrates, the internal carotid artery (ICA) supplies the brain and divides into two branches: a cranial and a caudal branch. The difference between vertebrates lies in the caudal branch of the ICA. For non-mammalian, the caudal branch is the origin of the BA, and the vertebral artery (VA) is not involved in brain supply. For mammals, the VA supplies encephalic arteries in two different ways. In the first type of organization, mostly found in ungulates, the carotid rete mirabile supplies the encephalic arteries, the caudal branch is the origin of the BA, and the VA is indirectly involved in carotid rete mirabile blood supply. The second type of encephalic artery organization for mammals is the same as in humans. The caudal branch of the ICA serves as the posterior communicating artery, and the BA originates from both VAs. We believe that knowledge of comparative anatomy of encephalic arteries contributes to a better understanding of animal models applicable to surgical or radiological techniques. It improves the understanding of rare encephalic variations that may be present in humans.

Diagnostic Performance of Carotid Ring Sign on CT-Angiography in Internal Carotid True Occlusion.

BACKGROUND: To differentiate between pseudo occlusion (PO) and true occlusion (TO) of internal carotid artery (ICA) is important in thrombectomy treatment planning for patients with acute ischemic stroke. Although delayed contrast filling has been differentiated carotid PO from TO, its application has been limited by the implementations of multiphasic computed tomography angiography. In this study, we hypothesized that carotid ring sign, which is readily acquired from single-phasic CTA, can sufficiently differentiate carotid TO from PO. METHODS: One thousand four hundred and twenty patients with anterior circulation stroke receiving endovascular therapy were consecutively recruited through a hospital- and web-based registry. Two hundred patients with nonvisualization of the proximal ICA were included in the analysis after a retrospective screening. Diagnosis of PO or TO of the cervical segment of ICA was made based on digital subtraction angiography. Diagnostic performances of carotid ring sign on arterial-phasic CTA and delayed contrast filling on multiphasic computed tomography angiography were evaluated and compared. RESULTS: One-hundred twelve patients had ICA PO and 88 had TO. Carotid ring sign was more common in patients with TO (70.5% versus 6.3%; P<0.001), whereas delayed contrast filling was more common in PO (94.9% versus 7.7%; P<0.001). The sensitivity and specificity of carotid ring sign in diagnosing carotid TO were 0.70 and 0.94, respectively, whereas sensitivity and specificity of delayed contrast filling was 0.95 and 0.92 in judging carotid PO. CONCLUSIONS: Carotid ring sign is a potent imaging marker in diagnosing ICA TO. Carotid ring sign could be complementary to delayed contrast filling sign in differentiating TO from PO, in particular in centers with only single-phasic CTA.

[Carotid Artery Stenting].

Currently, stricter indications for carotid artery stenosis are required owing to improvements in multifaceted medical treatment, including the intensive management of risk factors for atherosclerosis and lifestyle changes. High-risk factors for carotid artery stenting, such as vulnerable plaques, severe calcification, pseudo-occlusion, and difficult access, should be evaluated before endovascular intervention. Therefore, we need to understand the characteristics of each device to achieve maximum risk reduction for carotid artery stenting.

Orbital infarction syndrome following mechanical thrombectomy in internal carotid artery occlusion: a case report.

BACKGROUND: Orbital ischemic syndrome is a rare entity. The clinical signs typically demonstrate acute loss of visual acuity, chemosis, proptosis, ptosis, and total ophthalmoparesis. We report a case of a man who suffered an acute internal carotid artery occlusion and developed orbital ischemic syndrome after a mechanical thrombectomy. CASE PRESENTATION: A 57-year-old Vietnamese (Kinh ethnicity) man was brought to the emergency room with complaints of a speech disturbance, facial palsy, and severe weakness of the left arm and leg, which had started 4 hours earlier, after waking up. The National Institutes of Health Stroke Scale 12 (NIHSS 12) revealed the neurological score at admission. A head computed tomography scan showed no intracranial bleeding and an Alberta Stroke Program Early Computed Tomography Score (ASPECTS) of 8 on the right brain. Computed tomography angiography showed an occlusion of the right internal carotid artery. After that, a mechanical thrombectomy was performed, and the internal carotid artery was completely reperfused. After 10 hours, he experienced orbital pain, proptosis, ptosis, chemosis, and ophthalmoplegia of the right orbit. He also had acute loss of visual acuity, and fundoscopic examination revealed papilledema, no retinal hemorrhage, and no bruit in orbital auscultation. Intraocular pressure in the right eye was measured at 50.5 mmHg. Computed tomography angiography showed no carotid-cavernous fistula, but slight enlargement of the right medial and lateral rectus muscles. He was treated with steroids and hyperosmolar agents and recovered 7 days later, but had persistent loss of visual acuity in the right eye. CONCLUSION: Orbital ischemic syndrome is a rare complication after mechanical thrombectomy treatment in acute ischemic stroke that can lead to loss of visual acuity.

Stenting for Traumatic Pseudoaneurysms of the Cervical Internal Carotid Artery: Case Report and Systematic Review.

BACKGROUND: The optimal stenting approach for traumatic pseudoaneurysms (PSA) of the extracranial internal carotid artery (ICA) remains underinvestigated. We present a case of a traumatic pseudoaneurysm of the extracranial ICA managed with stenting and review of prior published similar cases. METHODS: The systematic review followed PRISMA-S guidelines and included studies that investigated traumatic pseudoaneurysms of the extracranial ICA managed by stent placement. Statistical analysis assessed the association between the type of injury and stent type, dual antiplatelet therapy (DAPT) duration, and clinical presentation, and the association between stent type and DAPT duration. RESULTS: Our search yielded 82 publications with 135 patients with extracranial ICA PSA treated with stenting. The odds of neck hematoma presentation was 12.2 times greater for patients with penetrating rather than blunt injuries (P = 0.000002). Covered stents had 2.02 times higher odds of use for penetrating rather than blunt injuries compared to bare metal stents. (P = 0.0029). Shorter duration DAPT was seen with bare metal stents having 1.25 higher odds of DAPT duration less than one month compared to covered (P = 0.001). CONCLUSIONS: In traumatic extracranial ICA pseudoaneurysms, covered stents are used more commonly for penetrating injuries compared to blunt injuries. Penetrating injuries are more strongly associated with the presentation of a hematoma compared to blunt injuries. Stent type may influence the recommended DAPT duration. Surgeons should consider these findings when selecting stent type and DAPT duration with patients presenting with traumatic extracranial ICA pseudoaneurysm.

Retropharyngeal abscess due to Fusobacterium necrophorum complicated by progressive internal carotid artery stenosis and multiple cranial nerve palsies.

BACKGROUND: A case of retropharyngeal abscess complicated by both artery and nerve injury has rarely been reported. METHODS: A 36-year-old woman suddenly presented with right eye visual loss, dilated pupil, reduced direct light reflex, ptosis and ocular motility disorder on the side of inflammation progression, and was diagnosed with retropharyngeal abscess due to Fusobacterium necrophorum. The patient was treated only with antibiotics and, no further surgery was necessary but tracheotomy. Four months later, MRA showed right ICA occlusion and left ICA stenosis. MRI revealed continuous spread of inflammation due to the abscess from the retropharyngeal to the intracranial space. RESULTS: These severe complications would be attributed to an endothelial damage to the arterial wall and an ischemic neuropathy caused by inflammation and thrombogenesis due to Fusobacterium necrophorum. CONCLUSIONS: This case should provide a better understanding of the mechanism of vascular and cranial nerve injury due to retropharyngeal infections, and highlights the need for early antibiotic therapy and repeated vascular evaluation.