Ipsilateral Internal Carotid Artery Research Articles

Anatomical Markers Associated With the Presence of Intracranial Aneurysms in Individuals Screened for Aneurysms

BACKGROUND Hemodynamic stress is linked to the development of intracranial aneurysms (IAs) and may be influenced by anatomic variation of intracranial arteries. We assessed diameters and bifurcation angles of intracranial arteries forming the circle of Willis in a cohort of individuals screened for the presence of IAs. METHODS Individuals with and without IAs identified at screening with magnetic resonance angiography were compared. Diameters and bifurcation angles of the following arteries were measured using semiautomatic methods: A1 and A2 segments of the anterior cerebral artery, M1 and M2 segments of the middle cerebral artery, P1 segments of the posterior cerebral artery, posterior communicating artery (Pcom), internal carotid artery, vertebral artery, and basilar artery. We employed univariate general linear models to assess group differences. This included subgroup comparisons between individuals with IAs at specific locations and matched controls, and comparisons on group level between individuals with and without IAs, corrected for age and sex. RESULTS In 94 of the 1049 individuals (9.0%) included, IAs were detected. Individuals with middle cerebral artery IAs had wider ipsilateral M2–M2 bifurcation angles compared with controls (121±25° versus 97±19°; P <0.01). Individuals with anterior communicating artery IAs showed smaller angles for the A1–A2 bifurcation (106±16° versus 120±17°; P  = 0.02), while those with Pcom IAs had wider Pcom–C7 bifurcation angles (147±14° versus 127±17°; P  = 0.02) and smaller diameters below the ipsilateral internal carotid artery top (2.86±0.36 mm versus 3.10±0.33 mm; P  = 0.03) compared with controls. CONCLUSION We found associations between wider M2–M2 bifurcation angles or narrower A1–A2 bifurcation angles and IA presence, consistent with prior literature. Moreover, we uncovered previously unexplored associations, including wider Pcom–C7 bifurcation angles and smaller internal carotid artery diameters in individuals with Pcom IAs. Future research should explore the potential of these markers in predicting IAs in at‐risk populations during follow‐up screenings.

Quantitative Analysis of the Supraorbital, Transorbital Microscopic, and Transorbital Neuroendoscopic Approaches to the Anterior Skull Base and Paramedian Vasculature

Abstract Objectives Our objective was to compare transorbital neuroendoscopic surgery (TONES) with open craniotomy and analyze the effect of visualization technology on surgical freedom. Design Anatomic dissections included supraorbital craniotomy (SOC), transorbital microscopic surgery (TMS), and TONES. Setting The study was performed in a neurosurgical anatomy laboratory. Participants Neurosurgeons dissecting cadaveric specimens were included in the study. Main Outcome Measures Morphometric analysis of cranial nerve (CN) accessible lengths, frontal lobe base area of exposure, and craniocaudal and mediolateral angle of attack and volume of surgical freedom (VSF) of the paraclinoid internal carotid artery (ICA), terminal ICA, and anterior communicating artery (ACoA). Results The mean (standard deviation [SD]) frontal lobe base parenchymal exposures for SOC, TMS, and TONES were 955.4 (261.7) mm2, 846.2 (249.9) mm2, and 944.7 (158.8) mm2, respectively. Access to distal vasculature was hindered when using TMS and TONES. Multivariate analysis estimated that accessing the paraclinoid ICA with SOC would provide an 11.2- mm3 increase in normalized volume (NV) compared with transorbital corridors (p < 0.001). There was no difference between the three approaches for ipsilateral terminal ICA VSF (p = 0.71). Compared with TONES, TMS provided more access to the terminal ICA. For the ACoA, SOC produced the greatest access corridor maneuverability (mean [SD] NV: 15.6 [5.6] mm3 for SOC, 13.7 [4.4] mm3 for TMS, and 7.2 [3.5] mm3 for TONES; p = 0.01). Conclusion SOC provides superior surgical freedom for targets that require more lateral maneuverability, but the transorbital corridor is an option for accessing the frontal lobe base and terminal ICA. Instrument freedom differs quantifiably between the microscope and endoscope. A combined visualization strategy is optimal for the transorbital corridor.

The Influence of Embolization of Internal Carotid Artery Aneurysms on Arterial Tortuosity: A Prospective Cohort Study

PurposeTo compare quantitative tortuosity descriptors of the internal carotid artery (ICA) after intracranial aneurysm embolization and to determine possible factors associated with its change. Materials and MethodsAn analysis of 52 patients with embolized intracranial aneurysms was performed. ICA tortuosity was assessed by digital subtraction angiograms obtained prior to the embolization and after the first follow-up examination. For each patient, tortuosity descriptors were calculated: relative length (RL), sum of angle metrics (SOAM), triangular index, product of angle distance (PAD), and inflection count metric (ICM). To represent changes in tortuosity for each descriptor, delta (Δ) value was defined as value of the descriptor prior to embolization minus value of the descriptor on follow-up examination. ResultsIn a median follow-up of 14 months, no statistically significant changes in tortuosity were observed on the nonembolized side. On the embolized side, SOAM (2.89 [SD ± 0.92] vs 2.38 [SD ± 0.94]; P < .001), PAD (5.01 [SD ± 1.83] vs 3.95 [SD ± 1.72]; P < .001), and ICM (12.18 [SD ± 4.55] vs 9.76 [SD ± 4.04]; P = .006) were significantly higher after embolization than before embolization. Median ΔRL (−0.02 [−0.045 to 0.002] vs −0.01 [−0.02 to 0.003]; P = .003), ΔPAD (0.84 [0.30–1.82] vs 0.10 [−0.001 to 1.10]; P < .001), and ΔICM (2.05 [0.42–3.50] vs 0.27 [0.02–2.16]; P = .004) were significantly higher on the embolized side. Tortuosity correlated with elapsed time after embolization. ConclusionsTortuosity of the ipsilateral ICA increased after intracranial aneurysm embolization.

Safety evaluation of sinus patency after stereotactic radiosurgery for transverse-sigmoid sinus dural arteriovenous fistulas: implications of treatment options for patients with Borden type I fistulas.

This study aimed to assess the efficacy and safety of stereotactic radiosurgery (SRS) in treating transverse-sigmoid sinus dural arteriovenous fistulas (TSS DAVFs), and to investigate post-SRS sinus patency, focusing on the risk factors associated with treated sinus occlusion. Data from 34 patients treated with SRS between January 2006 and April 2023 were analyzed. Detailed angioarchitecture was confirmed using digital subtraction angiography before SRS. Angiography of the ipsilateral internal carotid artery and vertebral artery was performed to evaluate whether the involved side of the TSS was used for normal venous drainage. TSS stenosis was defined as sinus diameter < 50% of the normal proximal diameter. DAVF shunt obliteration, TSS occlusion, neurological status, and adverse events were also evaluated. Of the 34 patients, 21 had Borden type I and 14 had Borden type II DAVFs. The median age at SRS was 64 years (interquartile range 54-71 years), and the follow-up period was 31 months (interquartile range 15-94 months). Complete shunt obliteration was achieved in 24 (70.6%) patients. The cumulative 2-, 3-, and 5-year shunt obliteration rates were 49.6%, 71.2%, and 86.0%, respectively. Borden type I had higher obliteration rates (60.5%, 83.1%, and 94.4%, respectively) than Borden type II (41.7%, 51.4%, and 75.7%, respectively; p = 0.034). TSS occlusion occurred in 5 patients (14.7%). The cumulative 1-, 5-, and 10-year TSS occlusion rates were 2.9%, 8.3%, and 23.6%, respectively, across the entire cohort. All occlusions occurred exclusively in the sinuses that were not used for normal venous drainage. Cox proportional analyses revealed that TSS stenosis and the sinus not being used for normal venous drainage were significantly associated with a greater risk of TSS occlusion after SRS (HR 9.44, 95% CI 1.01-77.13; p = 0.049). SRS is effective and safe for TSS DAVF and results in favorable shunt obliteration, symptom improvement, and low complication rates. TSS occlusion after SRS is asymptomatic and is limited to sinuses that are not used for normal venous drainage.

Association between preoperative cortical magnetic susceptibility and postoperative changes in the cerebral blood flow on cognitive improvement following carotid endarterectomy.

While patients who experience improved cognition following carotid endarterectomy (CEA) typically demonstrate restored brain perfusion after the procedure, it is worth noting that less than 50% of patients in whom postoperative cerebral blood flow (CBF) restoration is achieved actually show improved cognition after postoperatively. This suggests that factors beyond the mere restoration of CBF may play a role in postoperative cognitive improvement. Increased iron deposition in the cerebral cortex may cause neural damage, and quantitative susceptibility mapping (QSM) obtained using magnetic resonance imaging (MRI) quantifies magnetic susceptibility in the cerebral cortex, allowing for the assessment of iron deposition in vivo. The purpose of the present study was to determine whether preoperative cortical magnetic susceptibility as well as postoperative changes in CBF are associated with cognitive improvement after CEA. Brain MRI with a three-dimensional gradient echo sequence was preoperatively performed in 53 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), and QSM with brain surface correction and vein removal was obtained. Cortical magnetic susceptibility was measured in the cerebral hemisphere ipsilateral to surgery on QSM. Preoperatively and at two months after the surgery, brain perfusion single-photon emission computed tomography (SPECT) and neuropsychological assessments were conducted. Using these collected data, we evaluated alterations in CBF within the affected hemisphere and assessed cognitive improvements following the operation. A logistic regression analysis showed that a postoperative greater increase in CBF (95% confidence interval [CI], 1.06-1.90; p = 0.0186) and preoperative lower cortical magnetic susceptibility (95% CI, 0.03-0.74; p = 0.0201) were significantly associated with postoperatively improved cognition. Although sensitivity, specificity, and positive- and negative-predictive values with the cutoff value lying closest to the upper left corner of a receiver operating characteristic curve for the prediction of postoperatively improved cognition did not differ between postoperative changes in CBF and preoperative cortical magnetic susceptibility, the specificity and the positive-predictive value were significantly greater for the combination of postoperative changes in CBF and preoperative cortical magnetic susceptibility (specificity, 95% CI, 93-100%; positive-predictive value 95% CI, 68-100%) than for the former parameter alone (specificity, 95% CI, 63-88%; positive-predictive value 95% CI, 20-64%). Preoperative cortical magnetic susceptibility as well as postoperative changes in CBF are associated with cognitive improvement after CEA.

Abstract WP208: Infarction Size Affects Clinical Outcomes in Emergent Carotid Artery Stenting With Mechanical Thrombectomy

Background: Management of large vessel occlusion with extensive ipsilateral internal carotid artery (ICA) occlusion is unknown. We evaluated patients who underwent emergent carotid artery stenting (CAS) of the ICA with mechanical thrombectomy (MT). Methods: We retrospectively collected baseline demographic, clinical, and radiographic data on 27 patients who presented as a stroke alert within 24 hours of symptoms and had extensive (from bifurcation to distal ICA) occlusion by computerized tomography angiography from 2019-2023 at our institution. All patients underwent CAS with MT and received dual antiplatelet therapy. We measured outcomes by: (1) development of symptomatic ICH at 24 hours, (2) mortality, (3) Modified Rankin Scale (mRS) at 90 days, and (4) change in NIHSS at 24 hours. Baseline characteristics were reported by descriptive statistics. Statistical analyses were completed using Fisher’s exact test, Wilcoxon rank sum test, and logistic regression. Differences were statistically significant at p &lt; 0.05. Results: The mean age for our cohort was 64.5 ± 10.62 and nine patients were females (33.3%). Sixteen had M1 (59.3%) while 10 had M2 occlusion (37%), 14 patients received IV tPA (51.9%), and mean NIHSS at presentation was 15.6 ± 5.99. All patients achieved TICI 2b or TICI 3 recanalization. In our cohort, patients with lower ASPECT score 7.4 ± 1.8 compared to those with higher ASPECT score 9.0 ± 1.0 were more likely to have symptomatic ICH ( p = 0.032), and higher odds of mortality OR = 0.496, 95% CI (0.261-0.945). The development of symptomatic ICH at 24 hours following procedure was associated with severe disability (mRS 4-6) at 90 days ( p = 0.032). Administration of intravenous tPA was significantly associated with improvement of 4 or more points on NIHSS at 24 hours ( p = 0.032), but not with symptomatic ICH ( p = 0.419). Age, NIHSS at presentation, systolic blood pressure, and diabetes mellitus were not associated with mortality or symptomatic ICH. Conclusion: The area of infarction at the time of presentation (ASPECT score) is an essential factor in stratifying patient selection for emergent CAS during MT in extensive internal carotid artery occlusion. Further studies are needed to evaluate infarction size for safe interventions.

Abstract WP194: Quantified Effects of Intra-Arterial Vasodilatory Therapy for Cerebral Vasospasm

Introduction: Cerebral vasospasm is a major cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). Though used routinely in clinical practice, objective metrics to evaluate effectiveness of intra-arterial vasodilatory treatment (IAT) have not been identified. To quantify effects of IAT on flow dynamics in cerebral vasospasm, we retrospectively compared Lindegaard ratios (LR) of aSAH patients pre-and post-IAT. Methods: Subjects included 24 aSAH patients undergoing IAT in the bilateral middle cerebral arteries (MCA) for cerebral vasospasm, diagnosed by standard clinical and radiographic criteria. Subjects were excluded if balloon angioplasty was performed prior to/within 2 days of the index procedure. All subjects received 10 mg IA milrinone, a non-catecholamine phosphodiesterase inhibitor drug, per MCA. Transcranial doppler (TCD) ultrasound was measured pre-IAT (D0) and at D+1 and D+2 post-IAT. LR was calculated as the ratio of mean flow velocities in the middle cerebral artery (MCA) to the ipsilateral extracranial internal carotid artery. Standard threshold for vasospasm is defined as LR&gt;3. Results: Right and left LR were aggregated, total N=48. Average pre-IAT LR was 2.96 (R 2.67/L 3.25±1.29). Post-IA LR were 2.72±1.12 and 3.15±1.55 at D+1 and D+2, respectively. Subjects with pre-IA LR&gt;3 showed an average LR decrease of 21% post-IAT D+1 (p=0.01) and an 8% decrease at D+2 (p=0.16) [Fig.1A]. Subjects with pre-IAT&lt;3 experienced an average LR increase of 28% by D+2 (p=0.02) [Fig 1B]. Conclusion: Subjects with TCD confirmed vasospasm (LR&gt;3) at D0 showed a significant improvement in cerebral blood flow one day after therapy. Subjects who did not meet TCD threshold for vasospasm (LR&lt;3) showed little change one day post-IAT but worsening cerebral blood flow by day two post-IAT. Further study is needed to determine whether LR can be used to predict benefit or objectively assess effectiveness of IAT in aSAH patients with cerebral vasospasm.

Associations between atherosclerotic luminal stenosis in the distal internal carotid artery and diffuse wall thickening in its upstream segment.

Significant atherosclerotic stenosis or occlusion in the distal internalcarotid artery(ICA) may induce diffuse wall thickening (DWT) in the upstream arterial wall. This study aimed to assess the association of atherosclerotic steno-occlusive diseases in the distal ICA with DWT in the upstream ipsilateral ICA. Individuals with atherosclerotic stenosis in the distal ICA, detected by carotid MR vessel wall imaging using 3D pre- and post-contrast T1 volume isotropic turbo spin-echo acquisition (T1-VISTA) sequence, were enrolled. The associations of vessel wall thickening, the longitudinal extent of DWT, enhancement of the upstream ipsilateral ICA, and stenosis degree in the distal ICA were examined. Totally 64 arteries in 55 patients with atherosclerotic steno-occlusive distal ICAs were included. Significant correlations were found between distal ICA stenosis and DWT in the petrous ICA (r = 0.422, p = 0.001), DWT severity (r = 0.474, p < 0.001), the longitudinal extent of DWT in the ICA (r = 0.671, p < 0.001), enhancement in the petrous ICA (r = 0.409, p = 0.001), and enhancement degree (r = 0.651, p < 0.001). In addition, high degree of enhancement was correlated with both increased wall thickness and increased prevalence of DWT in the petrous ICA (both p < 0.001). DWT of the petrous ICA is commonly detected in patients with atherosclerotic steno-occlusive disease in the distal ICA. The degree of stenosis in the distal ICA is associated with wall thickening and its longitudinal extent in the upstream segments. Diffuse wall thickening is a common secondary change in atherosclerotic steno-occlusive disease in the intracranial carotid. This phenomenon constitutes a confounding factor in the distinction between atherosclerosis and inflammatory vasculopathies, and could be reversed after alleviated atherosclerotic stenosis. • Diffuse wall thickening of the petrous internal carotid artery is commonly detected in patients with atherosclerotic steno-occlusive disease in the distal internal carotid artery. • The phenomenon of diffuse wall thickening could be reversed after stenosis alleviation. • Carotid artery atherosclerosis with diffuse wall thickening should warrant a differential diagnosis from other steno-occlusive diseases, including moyamoya diseases and Takayasu aortitis.

Absence of periictal hyperperfusion on arterial spin labeling perfusion images in a patient with posttraumatic epilepsy and underdevelopment of ipsilateral internal carotid and middle cerebral arteries

Absence of periictal hyperperfusion on arterial spin labeling perfusion images in a patient with posttraumatic epilepsy and underdevelopment of ipsilateral internal carotid and middle cerebral arteries

Carotid stenosis and cryptogenic stroke

ObjectivesCryptogenic stroke represents a type of ischemic stroke with an unknown origin, presenting a significant challenge in both stroke management and prevention. According to the Trial of Org 10,172 in Acute Stroke Treatment criteria, a stroke is categorized as being caused by large artery atherosclerosis only when there is >50% luminal narrowing of the ipsilateral internal carotid artery. However, nonstenosing carotid artery plaques can be an underlying cause of ischemic stroke. Indeed, emerging evidence documents that some features of plaque vulnerability may act as an independent risk factor, regardless of the degree of stenosis, in precipitating cerebrovascular events. This review, drawing from an array of imaging-based studies, explores the predictive values of carotid imaging modalities in the detection of nonstenosing carotid plaque (<50%), that could be the cause of a cerebrovascular event when some features of vulnerability are present. MethodsGoogle Scholar, Scopus, and PubMed were searched for articles on cryptogenic stroke and those reporting the association between cryptogenic stroke and imaging features of carotid plaque vulnerability. ResultsDespite extensive diagnostic evaluations, the etiology of a considerable proportion of strokes remains undetermined, contributing to the recurrence rate and persistent morbidity in affected individuals. Advances in imaging modalities, such as magnetic resonance imaging, computed tomography scans, and ultrasound examination, facilitate more accurate detection of nonstenosing carotid artery plaque and allow better stratification of stroke risk, leading to a more tailored treatment strategy. ConclusionsEarly detection of nonstenosing carotid plaque with features of vulnerability through carotid imaging techniques impacts the clinical management of cryptogenic stroke, resulting in refined stroke subtype classification and improved patient management. Additional research is required to validate these findings and recommend the integration of these state-of-the-art imaging methodologies into standard diagnostic protocols to improve stroke management and prevention.

Abstract 093: Carotid Stump Syndrome: an Insidious Source of Recurrent Ischemic Strokes

Introduction Carotid stump syndrome (CSS) is a paradoxical phenomenon that occurs when there are repeated ischemic events in the carotid vascular territory despite demonstrated occlusion of the ipsilateral internal carotid artery (ICA). It is thought to be caused by turbulent blood flow in the patent stump of the occluded ICA creating microemboli which reach the brain through anastomotic channels and retrograde flow. We present a case of recurrent infarctions in setting of known ipsilateral ICA occlusion, who was diagnosed with carotid stump syndrome. Methods A male veteran in his 60s with a medical history of DVTs on apixaban, PVD, and ischemic stroke with residual right‐sided weakness, presented with worsening right‐sided weakness and difficulty with ambulation. Two months prior to the presentation he was diagnosed with acute infarcts in left frontal, parietal, and temporal lobes due to thromboembolism from left ICA occlusion. On presentation his neurological exam revealed right‐sided hemiparesis. MRI brain showed multiple acute and chronic cortical and subcortical infarcts in the left frontotemporoparietal lobes and lack of flow void in the left distal ICA. To further evaluate the dynamics of blood flow patient underwent a cerebral angiogram which confirmed the diagnosis of complete occlusion of left ICA and demonstrated reconstitution of the intracranial ICA through retrograde filling via the ophthalmic artery and anastomotic branches with the internal maxillary artery (IMax). For secondary prevention he was started on statin and aspirin while his home Apixaban was continued. Surgical and endovascular treatment approaches were discussed but the patient declined any intervention. In his four months follow up clinic visit he had no further concerns of recurrent strokes or new symptoms. Results Carotid stump syndrome is a rare cause of cerebral and retinal ischemia; however, it must be considered in patients with recurrent ischemic strokes and chronic ipsilateral ICA occlusion. Due to the patent proximal, or perhaps in some cases distal, carotid stump, there’s turbulent flow and hence the thrombus formation can occur. Hemodynamic and embolic factors attribute towards the microembolization from the proximal carotid stump through the external carotid artery (ECA), into the facial artery and IMax and their distal branches which anastomose with the ophthalmic artery, causing the emboli to end up in the major branches of the carotid terminus. If a distal stump is symptomatic, then the microemboli can readily end up in the distal ICA branches. In addition to medical management with DAPT or anticoagulation and high intensity statin, our literature review supports endovascular or surgical interventions due to reportedly good outcomes. Interventional approaches may include ECA‐ICA stenting with a covered stent or stent‐assisted coil embolization of the proximal stump. Surgical procedures include an endarterectomy on the ipsilateral ECA or contralateral ICA to increase collateral circulation. ECA‐ICA bypass is another option. Conclusion Carotid stump syndrome is a rare and underrecognized cause of recurrent ischemic strokes, though it is a potentially treatable entity. The therapeutic goals include medical management along with endovascular or surgical treatment whenever possible.

Non-arteritic anterior ischemic optic neuropathy associated with ipsilateral hypoplastic internal carotid artery.

Vascular insufficiency of the optic nerve head is the cause of non-arteritic ischemic optic neuropathy (NAION). Carotid artery abnormalities are now considered as a predisposing factor for developing NAION. In this report, we present a case of NAION associated with ipsilateral internal carotid artery hypoplasia. A 69-year-old female was referred for evaluating the cause of vision loss in her left eye. The patient was diagnosed with left NAION, however, the magnetic resonance imaging (MRI) showed a considerably smaller left internal carotid artery (ICA) than the right side. The magnetic resonance angiography (MRA) confirmed the disparity as well as perfusion abnormalities of intracranial carotid arteries. The diagnosis of left ICA hypoplasia was made and verified by depicting a left side small carotid canal on the computed tomography (CT) scan. This report suggests that ICA hypoplasia could be associated with NAION.

Abstract 059: The Tenzing‐Dotter Technique for Endovascular Management of Atherosclerotic Cervical ICA Tandem Large Vessel Occlusions

Introduction The endovascular treatment of acute ischemic stroke due to atherosclerotic occlusion/near‐occlusion of the cervical internal carotid artery (ICA) and a concurrent intracranial large vessel occlusion (LVO) remains challenging, and the optimal approach remains unclear. Options include initial angioplasty and/or stenting of the cervical lesion followed by intracranial thrombectomy versus Dotter navigation of catheters through the cervical lesion to first target the intracranial LVO. We describe a novel Tenzing‐Dotter technique which utilizes a Tenzing device for the Dotter delivery of large bore (0.070”) and super‐large bore (0.088”) catheters through cervical atherosclerotic lesions to gain access to the intracranial circulation in tandem LVO patients. Methods We performed a retrospective review our single center experience of atherosclerotic tandem occlusion patients in which the Route 92 Medical Tenzing ® 7 (T7®) and Tenzing ® 8 (T8®) delivery catheters were used to Dotter‐deliver large bore or super‐large bore catheters, respectively, through the cervical ICA lesion to gain access to the intracranial circulation. We reviewed clinical, radiographic and procedural data to describe the safety and efficacy of this approach. Results Twenty patients were identified that that atherosclerotic occlusion/near‐occlusion of the cervical ICA and a single symptomatic intracranial LVO. The mean age was 65 (44 – 89), and 40% were female. The mean NIHSS was 14 (7‐25) and 40% were treated initially with intravenous thrombolytics. The ipsilateral cervical ICA was occluded in 11 of 20 patients (55%) and nearly‐occluded (degree of stenosis 90‐99%) in 9 of 20 patients (45%). The intracranial occlusions were carotid terminus (5), M1 middle cerebral artery (14) and M2 middle cerebral artery (1). Seven patients were treated with Tenzing 7 paired with a large bore catheter (6 with Medtronic React 71 and 1 with Route 92 Medical Hipoint 70), while 13 were treated with Tenzing 8 paired with a super‐large bore catheter (11 with Route 92 Medical Hipoint 88 catheter and 2 with Route 92 Medical Freeclimb 88 catheter). In all cases, successful navigation of the paired catheter through the cervical lesion was achieved in 100% of patient using the Tenzing‐Dotter delivery technique. The mean time from groin puncture to successful Tenzing‐Dotter delivery was 11 minutes, and the mean time from groin puncture to device delivery to the intracranial occlusion was 15 minutes. TICI 2B or greater reperfusion (self‐adjudicated) as achieved in 100% of patients, with a mean time to best TICI of 21 minutes. The degree of cervical ICA stenosis following thrombectomy improved from 96.5% to 67.4%. No symptomatic intracranial hemorrhage or cervical arterial dissections were noted. Conclusion The Tenzing‐Dotter technique, in which a Route 92 Medical Tenzing ® delivery catheter is utilized to Dotter navigate a large or super‐large bore catheter through an occluded or nearly‐occluded cervical atherosclertotic lesion, may be a promising technique for safe and fast access to the intracranial circulation in patients presenting with tandem large vessel occlusion acute ischemic strokes.

Microsurgical strategies for small unruptured dorsal internal carotid artery aneurysms.

This study aimed to develop microsurgical strategies based on the anatomical relationship between dorsal internal carotid artery (ICA) aneurysms, the falciform ligament (FL), and the anterior clinoid process (ACP). Between 2017 and 2022, 25 patients with unruptured dorsal ICA aneurysms (less than 4 mm in diameter) underwent microsurgical direct clipping. These cases involved the left ICA (n=17) and the right ICA (n=8), with a mean aneurysm size of 3.3 mm (range, 2.5 to 4 mm). We used computed tomography angiography (CTA) and digital subtraction angiography to elucidate the anatomical relationship between dorsal ICA aneurysms and other structures. All procedures involved an ipsilateral pterional approach with securement of the ipsilateral cervical ICA for proximal control. Among the 25 dorsal ICA aneurysms, 8 (32%) were clipped without the FL being incised. Another 5 (20%) were clipped solely after the FL was cut. For the remaining 12 cases, the aneurysms were successfully clipped following FL incision and partial ACP removal. Patients exhibited favorable postoperative recoveries with good outcomes, and postoperative CTA revealed complete aneurysm clipping without any residual remnants. Conclusions: We were able to perform clipping without removing the ACP in 13 patients (52%), and in 8 of these (32%), the clipping was carried out directly without cutting the FL. Microsurgery, coupled with proximal control of the cervical ICA, can serve as a viable alternative for patients with small dorsal ICA aneurysms, especially when endovascular treatment options are limited, and 3D CTA confirms a clear anatomical relationship with the ACP.

Paraclinoid internal carotid artery aneurysm with delayed stent occlusion after deployment of a flow diverter stent involving the orifice of the anterior cerebral artery: illustrative case.

In-stent thrombotic occlusion is a serious ischemic complication that can also result in ischemia in the distal perfusion territory and the territory of side branches for the artery in which the flow diverter (FD) stent is deployed. A 49-year-old female with a large paraclinoid internal carotid artery (ICA) aneurysm was treated with an FD involving the orifice of the anterior cerebral artery (ACA). The antiplatelet dose was reduced because of an increased clopidogrel response postintervention. The patient developed aphasia 2 months later. Emergency magnetic resonance imaging and digital subtraction angiography of the brain indicated FD stent occlusion and a small infarct in the distal vascular territory of the ipsilateral ICA, but the anterior choroidal artery (AChoA) territory was preserved by collateral flow. Emergency superficial temporal artery to middle cerebral artery anastomosis was performed, and she was discharged without neurological deficit 2 weeks after the second operation. In-stent occlusion after FD deployment involving the orifice of the ACA can cause severe cerebral ischemia that requires an adequate antiplatelet effect and careful follow-up. The AChoA territory can be preserved by collateral blood flow even in cases of in-stent occlusion.

Transorbital Microsurgery: An Anatomical Description of a Minimally Invasive Corridor to the Anterior Cranial Fossa and Paramedian Structures

Abstract Objectives Transorbital neuroendoscopic surgery (TONES) has ignited interest in the transorbital access corridor, increasing its use for single and multi-portal skull base interventions. However, the crowding of a small corridor and two-dimensional viewing restrict this access portal. Design Cadaveric qualitative study to assess the feasibility of transorbital microsurgery (TMS). Setting Anatomical dissection steps and instrumentation were recorded for homogeneous methodology. Participants Six cadaveric specimens were systematically dissected using TMS to the anterior cranial fossa and paramedian structures. Main Outcome Measures Anatomical parameters of the TMS craniectomy were established, and the visible and accessible neuroanatomy was highlighted. Results A superior lid crease incision achieved essential orbital rim exposure and preseptal dissection. The orbital roof craniectomy is defined by three boundaries: (1) frontozygomatic suture to the frontosphenoid suture, (2) frontal sinus and cribriform plate, and (3) frontal sinus and orbital rim. The mean (standard deviation) craniectomy was 440 mm2 (78 mm2). Exposing the ipsilateral optic nerve and internal carotid artery obviated the need for frontal lobe retraction to identify the A1–M1 bifurcation as well as near-complete visualization of the M1 artery. Conclusion TMS is a feasible corridor for intracranial access. Mobilization of orbital contents is imperative for maximal intracranial access and protection of the globe. TMS enables access to the frontal lobe base, ipsilateral optic nerve, and most of the ipsilateral anterior circulation. This cosmetically satisfactory approach causes minimal destruction of the anterior skull base with satisfactory exposure of the anterior cranial fossa floor without sinus invasion.

Development of a rabbit human glioblastoma model for testing of endovascular selective intra-arterial infusion (ESIA) of novel stem cell-based therapeutics.

Endovascular selective intra-arterial (ESIA) infusion of cellular oncotherapeutics is a rapidly evolving strategy for treating glioblastoma. Evaluation of ESIA infusion requires a unique animal model. Our goal was to create a rabbit human GBM model to test IA infusions of cellular therapies and to test its usefulness by employing clinical-grade microcatheters and infusion methods to deliver mesenchymal stem cells loaded with an oncolytic adenovirus, Delta-24-RGD (MSC-D24). Rabbits were immunosuppressed with mycophenolate mofetil, dexamethasone, and tacrolimus. They underwent stereotactic xenoimplantation of human GBM cell lines (U87, MDA-GSC-17, and MDA-GSC-8-11) into the right frontal lobe. Tumor formation was confirmed on magnetic resonance imaging, histologic, and immunohistochemistry analysis. Selective microcatheter infusion of MSC-D24 was performed via the ipsilateral internal carotid artery to assess model utility and the efficacy and safety of this approach. Twenty-five rabbits were implanted (18 with U87, 2 MDA-GSC-17, and 5 MDA-GSC-8-11). Tumors formed in 68% of rabbits (77.8% for U87, 50.0% for MDA-GSC-17, and 40.0% for MDA-GSC-8-11). On MRI, the tumors were hyperintense on T2-weighted image with variable enhancement (evidence of blood brain barrier breakdown). Histologically, tumors showed phenotypic traits of human GBM including varying levels of vascularity. ESIA infusion into the distal internal carotid artery of 2 ml of MSCs-D24 (107 cells) was safe in the model. Examination of post infusion specimens documented that MSCs-D24 homed to the implanted tumor at 24 hours. The intracranial immunosuppressed rabbit human GBM model allows testing of ESIA infusion of novel therapeutics (eg, MSC-D24) in a clinically relevant fashion.

The Positional Relationship between Lacunae and White Matter Hyperintensity in Patients with Cerebral Small Vessel Disease.

Lacunae and white matter hyperintensity (WMH) are two crucial imaging biomarkers of cerebral small vessel disease (CSVD). Multiple studies have revealed a close relationship between WMH and lacunae and found that a double penumbra existed at the edge of WMH that affects lacunae formation. The study aimed to explore the spatial distribution characteristics and possible influencing factors of lacuna in relation to white matter hyperintensity in patients with CSVD. A total of 480 CSVD patients with WMH and with or without lacunae were included. Data about blood biochemical indicators, cerebrovascular CT angiography, 24-hour ambulatory blood pressure and ambulatory electrocardiogram, brain magnetic resonance imaging, and transcranial Doppler ultrasound were gathered from all subjects. They were categorised into four groups based on the spatial interaction between lacunae and WMH. Univariate analyses and multiple logistic regression analyses were used to compare the differences in traditional vascular risk factors, heart rate and blood pressure indicators, arterial pulsatility index (PI) values, and arterial stenosis among different groups. The average age of 480 patients was (58.63 ± 11.91) years, with 347 males (72.3%). Univariate analysis indicated that age, fasting blood glucose, triglycerides, total cholesterol, highdensity lipoprotein, 24-hour and daytime and night systolic and diastolic blood pressure, nocturnal heart rate, heart rate variability, PI values of ipsilateral and contralateral MCA (middle cerebral artery) and ICA (Internal carotid artery) of the lacunae, Fazekas score of PWMH (periventricular white matter hyperintensities), the proportion of MCA or ICA with stenosis rate over 50% on the ipsilateral side of the lacunae were significantly different between different groups (p < 0.05). High fasting blood glucose (OR=1.632, 95% CI= (1.128, 2.361), p =0.009), (OR=1.789, 95%CI= (1.270, 2.520), p = 0.001), (OR=1.806, 95% CI= (1.292, 2.524), p =0.001) was identified as a risk factor for lacunae formation by logistic regression analysis. High fasting blood glucose can be considered a risk factor for lacunae formation in patients with WMH. The more severe the PWMH and the higher the nocturnal heart rate, the more likely the lacunae, as well as PWMH, overlap completely. Ipsilateral arteriosclerosis and stenosis are independent risk factors for no contact between lacunae and PWMH.

Unilateral rete mirabile in multiple intracranial arteries with ipsilateral agenesis of the internal carotid artery: a case report

BackgroundRete mirabile of the cerebral artery is a rare anomaly, with most previous cases occurring in the middle cerebral artery or internal carotid artery. Here, we present the first report of unilateral rete mirabile in multiple intracranial arteries with ipsilateral internal carotid artery agenesis.Case presentationA 64-year-old Japanese woman was brought to the emergency department of our hospital in a deep coma. Computed tomography of the head showed severe intraventricular hemorrhage with subarachnoid hemorrhage. Computed tomography angiography showed not only congenital left internal carotid artery agenesis, but also rete mirabile of the left posterior communicating artery, the left posterior cerebral artery, and the left anterior cerebral artery. This unilateral vessel anomaly complex may have contributed to the formation of a peripheral aneurysm arising from a perforating branch of the pericallosal artery, which ruptured. The patient underwent urgent bilateral external ventricular drainage, but deteriorated and was declared brain dead.ConclusionsWe report the first case of unilateral rete mirabile in multiple intracranial arteries. Because the cerebral arteries in patients with rete mirabile may be vulnerable, close attention should be paid to the development of cerebral aneurysms.

Focal drug-resistant temporal lobe epilepsy associated with an ipsilateral anterior choroidal artery aneurysm: illustrative case.

The occurrence of both an intracranial aneurysm and epilepsy, especially drug-resistant epilepsy (DRE), is rare. Although the overall incidence of aneurysms associated with DRE is unclear, it is thought to be particularly infrequent in the pediatric population. Surgical ligation of the offending aneurysm has been reported in conjunction with resolving seizure activity, although few cases have cited a combined approach of aneurysm ligation and resection of an epileptogenic focus. We present the case of a 14-year-old female patient with drug-resistant temporal lobe epilepsy and an ipsilateral supraclinoid internal carotid artery aneurysm. Seizure semiology, electroencephalography monitoring, and magnetic resonance imaging all indicated a left temporal epileptogenic focus, in addition to an incidental aneurysm. The authors recommended a combined surgery involving resection of the temporal lesion and surgical clip ligation of the aneurysm. Near-total resection and successful ligation were achieved, and the patient has remained seizure free since surgery at 1 year postoperatively. In patients with focal DRE and an adjacent intracranial aneurysm, a combined surgical approach involving both resection and surgical ligation can be used. Several surgical timing and neuroanesthetic considerations should be made to ensure the overall safety and efficacy of this procedure.