A mathematical model to predict "low-lying" posterior communicating artery aneurysms in neurosurgical practice.

"Low-lying" posterior communicating artery (PCoA) aneurysms require great attention in surgical clipping due to their distinct anatomical characteristics. In this study, we propose an easy method to immediately recognize "low-lying" PCoA aneurysms in neurosurgical practice. A total of 89 cases with "low-lying" PCoA aneurysms were retrospectively analyzed. All patients underwent preoperative digital subtraction angiography (DSA) examinations and microsurgical clipping. Cases were classified into the "low-lying" and regular groups based on intraoperative findings. The distance- and angle-relevant parameters that reflected the relative location of the aneurysms and tortuosity of the internal carotid artery were measured using 3D-DSA images. The data were sequentially integrated into a mathematical analysis to obtain the prediction model. Finally, we proposed a novel mathematical formula to preoperatively predict the existence of "low-lying" PCoA aneurysms with great accuracy. Neurosurgeons might benefit from this model, which enables them to directly identify "low-lying" PCoA aneurysms and make appropriate surgical decisions accordingly.

Anatomical variations of sphenoid sinus in terms of volume and protrusions of optic nerve/internal carotid artery in a subgroup of Pakistani population.

Objective: To compare the volume of sphenoid sinus with protrusions of optic nerve and internal carotid artery in both males and females. METHODS: The cross-sectional study was conducted from October 2020 to February 2021 at the Radiology Department of Dow University of Health Sciences, Karachi, and comprised males and females aged 20-60 years having no sphenoid sinus bony abnormality. Sphenoid volume and optic nerve and internal carotid artery protrusions were examined in the computed tomography scans of the paranasal sinus. Based on the protrusions, the scan findings were split into four groups: Group 1 had no protrusion, Group 2 had optic nerve protrusion, Group 3 had internal carotid artery protrusion, and Group 4 had protrusions of both the optic nerve and the internal carotid artery. Data was analysed using GraphPad Prism 9. RESULTS: Of the 300 subjects, 171(57%) were males and 129(43%) were females. The overall mean age was 39.27±10.9 years. There were 147(49%) subjects in group 4, followed by 72(24%) in group 3, 42(14%) in group 2 and 39(13%) in group 1. Statistically significant difference was observed between sphenoid volume across the study groups for both male and female subjects (p<0.001). Conclusion: There was significant relationship between internal carotid artery and optic nerve protrusions and sphenoid volume.

Contrast enhancement boost improves the image quality of CT angiography derived from 80-kVp cerebral CT perfusion data.

RATIONALE AND OBJECTIVE: To investigate the impact of the contrast enhancement boost (CE-boost) technique on the image quality of CT angiography (CTA) derived from 80-kVp cerebral CT perfusion (CTP) data, and to compare it with conventional CTApeak as well as other currently employed methods for enhancing CTA images, such as CTAtMIP and CTAtAve extracted from CTP. MATERIALS AND METHODS: The data of forty-seven patients who underwent CTP at 80 kVp were retrospectively collected. Four sets of images: CTApeak, CTAtMIP, CTAtAve, and CE-boost images. The CTApeak image represents the arterial phase at its peak value, captured as a single time point. CTAtMIP and CTAtAve are 4D CTA images that provide maximum density projection and average images from the three most prominent time points. CE-boost is a postprocessing technique used to enhance contrast in the arterial phase at its peak value. We compared the average CT value, standard deviation (SD), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of the internal carotid artery (ICA) and basilar artery (BA) among the four groups. Image quality was evaluated using a 5-point scale. RESULTS: The CE-boost demonstrated and CNR in the ICA and BA (all p < 0.001). Compared with the other three CTA reconstructed images, the CE-boost images had the best subjective image quality, with the highest scores of 4.77 ± 0.43 and 4.87 ± 0.34 for each reader (all p < 0.001). CONCLUSION: Compared with other currently used techniques,CE-boost enhances the image quality of CTA derived from 80-kVp CTP data, leading to improved visualization of intracranial arteries.

[Neurovascular pathology in a patient with neurofibromatosis type 1. Case report]. / Patología neurovascular en el paciente con neurofibromatosis de tipo 1. A propósito de un caso.

INTRODUCTION: Neurovascular involvement in patients with neurofibromatosis type 1 (NF1) presents with a wide spectrum of manifestations. Its frequency is low, albeit probably underestimated. There is currently no known specific treatment, and treatment is based on recommendations with limited evidence. This report describes a case of vascular dysplasia in a patient with NF1. CASE REPORT: A 67-year-old woman with a genetic diagnosis of NF1 and a history of multiple exeresis of neurofibromas in the left cervical region. The patient presented with a painful flare-up and swelling in the region. A cervical magnetic resonance imaging was performed, which showed signs of plexiform neurinoma growth and a lesion suggestive of aneurysm in the left cervical internal carotid artery. A subsequent computed tomographic angiography confirmed the presence of a thrombosed aneurysm with associated critical stenosis, and identified three additional aneurysms in the proximal left vertebral artery. Given the asymptomatic presentation and adequate haemodynamic compensation, the patient was prescribed a conservative treatment and clinicoradiological follow-up. CONCLUSIONS: Neurovascular alterations associated with NF1 are infrequent, and the optimal treatment for them is unknown. Studies to define its true prevalence, determine its pathophysiological substrate and estimate the risk of cerebrovascular complications more precisely are needed. This could provide more robust recommendations for the population of NF1 patients, especially in asymptomatic cases.

TITLE: Patología neurovascular en el paciente con neurofibromatosis de tipo 1. A propósito de un caso.Introducción. La afectación neurovascular en pacientes con neurofibromatosis de tipo 1 (NF1) cursa con un amplio espectro de manifestaciones y su frecuencia es baja, aunque probablemente infraestimada. En la actualidad, su tratamiento específico se desconoce y se basa en recomendaciones con bajo nivel de evidencia. Se describe un caso de displasia vascular en una paciente con NF1. Caso clínico. Mujer de 67 años con diagnóstico genético de NF1 e historia de exéresis múltiple de neurofibromas en la región cervical izquierda. La paciente presentaba un cuadro de reagudización dolorosa y tumefacción en dicha región, por lo que se le realizó una resonancia magnética cervical, que mostró signos de crecimiento de neurinomas plexiformes y una lesión sugestiva de aneurisma en la arteria carótida interna izquierda cervical. Un estudio de angiotomografía computarizada posterior confirmó la presencia de un aneurisma trombosado con estenosis crítica asociada e identificó tres aneurismas adicionales en la arteria vertebral izquierda proximal. Ante la presentación asintomática y la adecuada compensación hemodinámica, se decidió tratamiento conservador y seguimiento clinicorradiológico. Conclusiones. Las alteraciones neurovasculares asociadas a la NF1 son infrecuentes y su tratamiento óptimo se desconoce. Son necesarios estudios que definan con mayor precisión su prevalencia real, su sustrato fisiopatológico y una estimación del riesgo de complicaciones cerebrovasculares. De este modo, se podrían ofrecer recomendaciones más sólidas para la población de pacientes con NF1, especialmente en los casos asintomáticos.

Spontaneous Right Intrapetrous Internal Carotid Dissection in a Patient With Active COVID-19.

Spontaneous cervical artery dissection, a nontraumatic tear in the wall of an internal carotid or vertebral artery, is a common cause of stroke, particularly in patients younger than 40 years of age; however, petrous internal carotid artery dissection is extremely rare. This case report describes a 50-year-old woman who had a spontaneous intrapetrous internal carotid dissection thought to be secondary to active SARS-CoV-2 infection; the dissection was treated successfully with a flow-diverter stent.

Anterior clinoidectomy in low lying internal carotid artery-posterior communicating artery aneurysm.

BACKGROUND: At times, a regulation internal carotid artery-posterior communicating artery junction (ICA-P-Comm) aneurysm becomes a surgical hurdle owing to its close proximity to the anterior clinoid process, an immovable ICA and a concealed dominant P-Comm artery arising from the aneurysm neck. METHOD: A 70 year old patient with a low lying ICA-P-Comm aneurysm underwent a "tailored" intradural clinoidectomy for aneurysm clipping. CONCLUSION: A tailored anterior clinoidectomy to expose "just enough" allows a proximal ICA control in a suitable area, mobility of an atherosclerotic ICA and exposes the P-Comm artery origin which are essential in safe clipping of these aneurysms.

The relationship between bone health and type of intracranial internal carotid calcifications in patients with ischemic stroke.

INTRODUCTION: Vascular calcifications, primarily in the aorta and its proximal branches, are commonly observed among subjects with impaired bone health. In this study, we sought to determine if a comparable association holds true for the calcifications in the intracranial internal carotid arteries (IICA), in general and also for particular calcification patterns. METHODS: A consecutive series of ischemic stroke patients were prospectively enrolled into the study, where computed tomography angiography source images were used to determine the presence and type of IICA calcifications, and dual-energy X-ray absorptiometry was used to determine the bone mineral density in the left femoral neck region. IICA calcifications were categorized as none, intimal, medial, and mixed types based on previously validated classification schemes. Their relationships with femoral bone T-scores were evaluated by bivariate and multivariate analyses. RESULTS: Femoral neck T-score was highest among patients without any vascular calcifications (n=65), when compared to the bone density measures among patients with any type of calcification (n=185) (p<0.001). After adjustment for age, gender, vascular risk factors, and serum biomarkers related to bone health, the T-score remained significantly associated only with the pattern of intimal calcification [OR 0.63 (0.42 - 0.95), p=0.028]. CONCLUSIONS: Our findings suggest that the intracranial vasculature, in particular the internal carotid arteries, is not immune to the interplay between suboptimal bone health and vascular calcifications. This association was most robust for an intimal type of IICA calcification pattern, while no such relationship could be demonstrated for other types of vascular calcifications.

Anatomical variations of the extracranial internal carotid artery: prevalence, risk factors, and imaging insights from CT-angiography.

PURPOSE: To determine the prevalence of different extracranial internal carotid artery (EICA) variations in CT angiography (CTA) of the neck and its predisposing factors. METHODS: In this retrospective study from 2021 to 2023 conducted in the radiology department of Shafa Hospital, Kerman, Iran, all patients who had undergone neck CTA were included. Expert radiologists blindly examined each CTA image for the following: EICA variations-coiling, kinking, straight morphology, and tortuosity-and the distance between the internal carotid artery and the apex of the epiglottis and the C2 lower margin. RESULTS: Of the 106 patients, the mean age was 55.9 ± 16.9 years. 64.2% were men, and 35.8% were women. Considering each patient's bilateral anatomy, the reported 70.28% (149/212) frequency of EICA variations of all arteries. Tortuosity, kinking, and coiling variation were found in 61.8%, 4.2%, and 4.2% of arteries, respectively. Also, 54.72%, 1.89%, and 0.94% of the participants had bilateral tortuosity, kinking, and coiling, respectively. There was a significant relationship between the prevalence of EICA variations and female sex, age, and hypertension. CONCLUSION: The frequency of EICA variations in arteries and patients was 70.28% and 73.58%, respectively. Tortuosity was the most common variation. Female sex, old age, and hypertension were significant risk factors for EICA variations.

Accuracy of duplex ultrasonography versus angiotomography for the diagnosis of extracranial internal carotid stenosis.

INTRODUCTION: Internal carotid artery (ICA) stenosis causes about 15% of ischemic strokes. Duplex ultrasonography (DUS) is the first line of investigation of ICA stenosis, but its accuracy varies in the literature and it is usual to complement the study with another more accurate exam when faced with significant stenosis. There is a lack of studies that compare DUS with angiotomography (CTA) in the present literature. METHODS: we performed an accuracy study, which compared DUS to CTA of patients in a tertiary hospital with a maximum interval of three months between tests. Patients were selected retrospectively, and two independent and certified vascular surgeons evaluated each image in a masked manner. When there was discordance, a third evaluator was summoned. We evaluated the diagnostic accuracy of ICA stenosis of 50-94% and 70-94%. RESULTS: we included 45 patients and 84 arteries after inclusion and exclusion criteria applied. For the 50-94% stenosis range, DUS accuracy was 69%, sensitivity 89%, and specificity 63%. For the 70-94% stenosis range, DUS accuracy was 84%, sensitivity 61%, and specificity 93%. There was discordance between CTA evaluators with a change from clinical to surgical management in at least 37.5% of the conflicting reports. CONCLUSION: DUS had an accuracy of 69% for stenoses of 50-94% and 84% for stenoses of 70-94% of the ICA. The CTA analysis depended directly on the evaluator with a change in clinical conduct in more than 37% of cases.

Necessary to continue imaging spontaneous cervical artery dissecting pseudoaneurysms after one year?

BACKGROUND AND PURPOSE: The value of long-term serial imaging of dissecting pseudoaneurysm (dPSA) is poorly characterized. This study investigated the long-term radiographic evolution of dPSA. METHODS: We performed a query in our institutional craniocervical artery dissection registry to identify cases with spontaneous dPSA who had at least one year of follow-up with serial angiographic imaging. We performed Wilcoxon rank-sum pairwise comparison test to determine if there was a significant change in the aneurysm size over time. RESULTS: This observational cohort study included 76 patients (46 females; 64 dPSA in the internal carotid artery [ICA] and 12 in the vertebral artery [VA]) with a median age of 49.5 years (range 24-77). The initial median dPSA size was 8 mm (interquantile range(iqr) = 5.88-11mm), and the final median dPSA size was 7 mm (iqr = 4-11 mm). Most patients had either no change or reduction in dPSA size in the serial follow-up, with no significant change over time. All the patients had favorable outcomes at the last follow-up, and most patients were symptom-free from dPSA (92 %). Two patients (2.6%) experienced recurrent ischemic strokes in the same territory as the initial ischemic stroke without any change in dPSA size. CONCLUSION: Further serial scans for dPSA after one year may be deferred in the absence of interim clinical symptoms as most dPSA either remains stable or decreases in size. Recurrent stroke, although a rare event, was not associated with an increase in dPSA size.

Territory-Related Functional Connectivity Changes Associated with Verbal Memory Decline in Patients with Unilateral Asymptomatic Internal Carotid Stenosis.

BACKGROUND AND PURPOSE: Verbal memory decline is a common complaint of patients with severe asymptomatic stenosis of the internal carotid artery (aICS). Previous publications explored the associations between verbal memory decline and altered functional connectivity (FC) after aICS. Patients with severe aICS may show reduced perfusion in the ipsilateral territory and redistribution of cerebral blood flow to compensate for the deficient regions, including expansion of the posterior and contralateral ICA territories via the circle of Willis. However, aICS-related FC changes in anterior and posterior territories and the impact of the sides of stenosis were less explored. This study aims to investigate the altered FC in anterior and posterior circulation territories of patients with left or right unilateral aICS and its association with verbal memory decline. MATERIALS AND METHODS: We enrolled 15 healthy controls (HCs), 22 patients with left aICS (aICSL), and 33 patients with right aICS (aICSR) to receive fMRI, Mini-Mental State Examination (MMSE), the Digit Span Test (DST), and the 12-item Chinese version of Verbal Learning Tests. We selected brain regions associated with verbal memory within anterior and posterior circulation territories. Territory-related FC alterations and verbal memory decline were identified by comparing the aICSL and aICSR groups with HC groups (P < .05, corrected for multiple comparisons), respectively. Furthermore, the association between altered FC and verbal memory decline was tested with the Pearson correlation analysis. RESULTS: Compared with HCs, patients with aICSL or aICSR had significant impairment in delayed recall of verbal memory. Decline in delayed recall of verbal memory was significantly associated with altered FC between the right cerebellum and right middle temporal pole in the posterior circulation territory (r = 0.40, P = .03) in the aICSR group and was significantly associated with altered FC between the right superior medial frontal gyrus and left lingual gyrus in the anterior circulation territory (r = 0.56, P = .01) in the aICSL group. CONCLUSIONS: Patients with aICSL and aICSR showed different patterns of FC alterations in both anterior and posterior circulation territories, which suggests that the side of aICS influences the compensatory mechanism for decline in delayed recall of verbal memory.

How I do it: operative nuances of the Encephalo-Duro-Mio-Synangiosis (EDMS) technique for pediatric moyamoya disease and syndrome.

BACKGROUND: Moyamoya disease, a progressive occlusive arteriopathy mainly affecting the supraclinoid internal carotid artery, leads to abnormal "Moyamoya vessels" and ischemic events in children due to decreased cerebral blood flow. Surgery, especially indirect revascularization, is suggested for pediatric Moyamoya cases. METHOD: We present the Encephalo-Duro-Mio-Synangiosis (EDMS) technique, illustrated with figures and videos, based on 14 years' experience performing 71 surgeries by the senior author (SGJ) and the Moyamoya Interdisciplinary Workteam at "Prof. Dr. J. P. Garrahan" Pediatric Hospital. CONCLUSION: EDMS is a simple and effective treatment for Moyamoya disease, enhancing procedure precision and safety, reducing associated risks, complications, and improving clinical outcomes.

Measuring global cerebrovascular pulsatility transmission using 4D flow MRI.

Pulse wave encephalopathy (PWE) is hypothesised to initiate many forms of dementia, motivating its identification and risk assessment. As candidate pulsatility based biomarkers for PWE, pulsatility index and pulsatility damping have been studied and, currently, do not adequately stratify risk due to variability in pulsatility and spatial bias. Here, we propose a locus-independent pulsatility transmission coefficient computed by spatially tracking pulsatility along vessels to characterise the brain pulse dynamics at a whole-organ level. Our preliminary analyses in a cohort of 20 subjects indicate that this measurement agrees with clinical observations relating blood pulsatility with age, heart rate, and sex, making it a suitable candidate to study the risk of PWE. We identified transmission differences between vascular regions perfused by the basilar and internal carotid arteries attributed to the identified dependence on cerebral blood flow, and some participants presented differences between the internal carotid perfused regions that were not related to flow or pulsatility burden, suggesting underlying mechanical differences. Large populational studies would benefit from retrospective pulsatility transmission analyses, providing a new comprehensive arterial description of the hemodynamic state in the brain. We provide a publicly available implementation of our tools to derive this coefficient, built into pre-existing open-source software.

Ischemic stroke due to stylocarotid artery syndrome: a case report and review.

Stylocarotid artery syndrome (SAS) is a rare variant of Eagle's syndrome that may lead to transient ischemic attack or stroke. The underlying pathophysiological mechanism involves compression of the internal carotid artery by an elongated styloid process (ESP), potentially resulting in vascular occlusion or dissection. An ESP exceeding 2.5 cm is deemed elongated, with a length of 3.0 cm considered clinically significant. Although the prevalence of ESP ranges from 4.0% to 7.3%, symptomatic cases are rare; symptoms are present in only approximately 4.0% of individuals with an ESP. Unlike the typical symptoms of Eagle's syndrome, SAS may not cause pharyngeal discomfort, the sensation of a foreign body in the throat, dysphagia, or facial pain. This absence of characteristic symptoms as well as the development of central nervous system symptoms often leads patients to seek care from neurologists instead of otolaryngologists, increasing the likelihood of misdiagnosis or underdiagnosis. We herein report a unique case of ischemic stroke caused by SAS and present a literature review on cases of SAS-associated ischemic stroke published in the past decade. The reporting of this study conforms to the CARE guidelines.

Distal normal vessel diameter might be associated with silent brain infarcts after stenting for symptomatic carotid stenosis.

BACKGROUND: Carotid artery stenting (CAS) has been the standard treatment for carotid stenosis because it is less invasive; however, the risk of periprocedural thromboembolism is high. We investigated the predictors for silent brain infarcts (SBIs), focusing on embolic protection in CAS. METHODS: This study was single-center retrospective study, and we obtained baseline demographics and clinical, laboratory, and periprocedural variables of patients who underwent CAS. Also, methods used for embolic protection (no EPD, distal EPD, or proximal balloon guiding catheter) during CAS were obtained. Distal normal vessel diameter was defined as the diameter of cervical internal carotid artery where the artery wall becomes parallel. Diffusion-weighted imaging was performed before and after procedure to detect SBIs. The primary outcome was stented territory SBIs, and the secondary outcomes were any territories SBIs and stented territory SBIs in cases with EPD. RESULTS: A total of 196 CAS procedures with mean age 69.1 ± 9.9 years were included. After CAS, stented territory SBIs occurred in 53 (27.0 %) cases and any territories SBIs in 60 (30.6 %) cases. Univariable analyses revealed that distal normal vessel diameter (odds ratio = 1.71, 95 % confidence interval = 1.20-2.43, P = 0.003) was associated with the occurrence of stented territory SBIs after CAS. After adjusting for potential variables, larger distal normal vessel diameter (1.61 [1.10-2.36], P = 0.014) increased the occurrence of SBIs after CAS. Consistent results were obtained when the outcome was any territories SBIs or stented territory SBIs in cases with EPD. CONCLUSIONS: Distal normal vessel diameter was a predictor for the occurrence of SBI after CAS. The passable pore size of EPDs may vary depending on vessel diameter, and may impact the occurrence of SBIs.

[Functional assessment of internal carotid artery tortuosity in patients with multifocal atherosclerosis]. / Vazhnost' dinamicheskoi funktsional'noi otsenki patologicheskoi izvitosti vnutrennikh sonnykh arterii u bol'nykh s mul'tifokal'nym aterosklerozom.

The review is devoted to diagnosis and treatment of internal carotid artery tortuosity. The authors consider modern classification, epidemiology and diagnostic options using neuroimaging or ultrasound-assisted functional stress tests depending on medical history and complaints. In addition to standard Doppler ultrasound, rotational and orthostatic tests are advisable due to possible changes of local shape and hemodynamic parameters following body position changes, especially in patients with concomitant atherosclerotic stenosis. Thus, a personalized approach is especially important for treatment and diagnostics of internal carotid artery tortuosity.

Acute Glaucoma Following Internal Carotid Artery Stenting: A Rare But Serious Complication of Ocular Ischemic Syndrome.

Acute glaucoma following carotid artery recanalization is a rare but severe complication of underlying ocular ischemic syndrome. We present a case of a 71-year-old woman with ocular ischemic syndrome and severe stenosis of the right internal and external carotid artery undergoing carotid artery stenting. Immediate postprocedural angiography showed pronounced reperfusion of the ophthalmic artery. Subsequently, the patient developed vision-threatening acute glaucoma despite treatment with acetazolamide. Monitoring of intraocular pressure is important in patients who are at risk of developing ocular ischemic syndrome because of internal carotid artery stenosis. Interventionalists should also assess the degree of vascular collateralization from the external carotid artery.

Assessment of Dynamic Cerebral Autoregulation During Long-Term Exposure to High Altitude in Normal Subjects by Ultrasonography.

PURPOSE: To evaluate changes in dynamic cerebral autoregulation (CA) during short-term and long-term exposure to high altitude with ultrasonography, and also study the sex differences in the response of CA to altitude. METHODS: We assessed the differences in dynamic CA and measured with Doppler ultrasound of the bilateral internal carotid artery (ICA), vertebral artery (VA), and middle cerebral artery (MCA) and the values of basic information within 48 hours and at 2 years after arrival at Tibet in 65 healthy Han young Chinese volunteers, meanwhile, we compared the resistance index (RI) and pulsatility index (PI) of the right MCA at inhale oxygen 8 minutes when a newcomer with 2 years after arrival at Tibet. RESULTS: With 2 years of altitude exposure, the SaO2 of all subjects was above 90%, the mean PEF, DAP, and HR values decreased, HGB increased compared within 48 hours in same-gender groups. Comparisons of cerebral hemodynamics between before 2 years and after 2 years within male and female groups, the mean RI and PI values of bilateral MCA after 2 years were significantly higher than before 2 years, at the same time, the mean RI and PI values of bilateral ICA were significant differences (P < .05) between male groups, with regard to female groups, showed that the mean RI and PI values of bilateral VA were significant differences (P < .05). Comparisons of Right MCA hemodynamics between after oxygen uptake 8 minutes and 2 years, the mean RI and PI values were no significant difference within male and female groups (P > .05). CONCLUSIONS: Acute mountain sickness could result from an alteration of dynamic autoregulation of cerebral blood flow, but the impaired autoregulation may be corrected with the extension of time, furthermore, the response of CA to altitude in males and females are different.