Posterior Cerebral Artery Territory Research Articles

Impact of early physiotherapy intervention in managing homonymous hemianopia due to posterior cerebral artery infarct—a case report

Homonymous hemianopia field loss can develop as a result of injury to any part of the retro chiasmal visual pathway and is frequently fatal for subjects. The most common cause of homonymous hemianopia in older persons is ischemic infarction of the occipital lobe and its causes are multifactorial, frequently providing a diagnostic challenge to the clinician and signaling the necessity for a thorough systemic health review. Hemianopia is a loss of half of the visual field in each eye in which the inner or nasal half of one eye and the outer or temporal half of the other eye is affected. We report a case of a 72-year-old male subject who visited our department with complaints of weakness on the right side with difficulty seeing on the right side for 3 days. After undergoing various investigations, it was found that there is an acute infarct in the posterior cerebral artery territory supplying the left medial temporal lobe, medial occipital lobe, left thalamus, and splenium of the corpus callosum. After a physiotherapeutic examination provisionally, he was diagnosed with right hemiparesis and homonymous hemianopia, and thus, we administered an early physical therapy intervention which was found to be effective.

Multi-modal Magnetic Resonance Imaging to Assess Cerebrovascular Function in Atrial Fibrillation Patients

Atrial fibrillation (AF) is associated with an increased risk of cognitive decline, dementia, and stroke. Low cerebral blood flow (CBF) and low cerebrovascular carbon dioxide reactivity (CVRCO2) are associated with poor brain health outcomes. In the current study we employed magnetic resonance imaging (MRI) to quantify resting CBF and CVRCO2 in patients with AF and age-matched normal sinus rhythm (NSR) controls. We hypothesised that both resting CBF and CVRCO2 would be lower in patients with AF. Patients with AF (n=11, 65±14 years, 2 women) and NSR (n=12, 63±9 years, 7 women) underwent arterial spin labelling (ASL) at rest, and blood oxygen level-dependent (BOLD) MRI during a single-step increase in partial pressure of carbon dioxide (measured by end-tidal carbon dioxide (PETCO2)) induced by changing the fraction of inspired CO2 to 5% (21% O2, balance N2). Region of interest time courses were extracted with grey matter, middle cerebral artery, and posterior cerebral artery territory masks. CVRCO2 was defined as the percentage change (%Δ) in BOLD signal vs %Δ in PETCO2. Baseline CBF was not different between NSR and AF in grey matter (62±17 vs. 58±10 ml/min/100g, respectively; p=0.226), middle cerebral artery (59±16 vs. 56±14 ml/min/100g; p=0.361) and posterior cerebral artery (61±17 vs 53±15 ml/min/100g; p=0.138) territories. BOLD-derived CVRC02 was not different between NSR and AF groups in grey matter (0.11±0.04 vs. 0.12±0.03 %ΔBOLD/%ΔmmHg, respectively; p=0.372), middle cerebral artery (0.09±0.04 vs. 0.10±0.03 %ΔBOLD/%ΔmmHg; p=0.405) and posterior cerebral artery (0.13±0.04 vs. 0.14±0.05 %ΔBOLD/%ΔmmHg; p=0.367) territories. Collectively, these pilot data suggest that MRI-derived cerebrovascular CO2 responsiveness is not different in patients with AF and age-matched NSR controls that have similar resting CBF. Further investigations are required to extend these preliminary findings to a larger cohort to fully elucidate the effects of AF on cerebrovascular function. Support provided by the Royal Society of New Zealand Te Apārangi Marsden Fund (19-UOA-170). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Undoubtedly unaware of homonymous hemianopia: The contribution of overconfidence to anosognosia of hemianopia

A new functional deficit caused by a stroke can be understood as a situation of uncertainty that has to prompt deficit discovery and subsequent incorporation into an altered self-perception. Anosognosia for visual field deficits is frequent after stroke. For hemiplegia, patients' performance in a riddle test provided evidence that the inability to generate and adjust beliefs in face of uncertainty contributes to anosognosia for hemiplegia. In this prospective study, the same riddles are used in patients with homonymous hemianopia due to a first-ever stroke in the posterior cerebral artery territory and in an age-matched control cohort. The riddles create a situation of uncertainty that is resolved with five successive clues which progressively delimit the target word. After each clue, patients have to guess the target word and rate their confidence in the answer's correctness. Patients were tested once during the hospital stay. According to the Bisiach score for anosognosia, 12 out of 29 patients were unaware of their visual field deficits. All patients with anosognosia for hemianopia had right hemisphere lesions. Patients with and without anosognosia did not differ significantly in global cognitive impairment, mental flexibility or memory function. Importantly, patients with anosognosia showed higher confidence ratings than patients without anosognosia and controls in the first two clues (situations of uncertainty). This was demonstrated by a significant interaction effect in a mixed ANOVA with the factors group (anosognosia, nosognosia, controls) and riddle clues. An exploratory lesion subtraction analysis showed a high proportion of deficit unawareness in patients with lesions in the right fusiform and (para)hippocampal gyri. Our findings suggest that overconfidence in situations of uncertainty might contribute to the appearance of anosognosia for hemianopia. Because this has been demonstrated before in anosognosia for hemiplegia, we suggest that overconfidence is a supra-modal contributor to deficit unawareness.

Diabetic ketoacidosis with central nervous system involvement: Conventional and advanced magnetic resonance neuroimaging findings.

Diabetic ketoacidosis (DKA) is a serious complication in children with diabetes mellitus type 1 (DM1). In rare and severe cases DKA may be complicated by cerebral edema, central brain herniation and cerebral infarctions. We present the magnetic resonance imaging findings in a child with DKA and central nervous system involvement; diffusion tensor imaging (DTI) and functional MRI (fMRI) were performed to assess the white matter integrity of sensory pathways and cortical sensory processing. Conventional imaging showed bilateral uncal herniation, effacement of the perimesencephalic cisterns, wide ischemic lesions in the posterior cerebral artery (PCA) territories, sagging brainstem and Duret's hemorrhage consistent with signs of central brain herniation and intracranial hypertension. Advanced MRI showed a possible left-sided cortical reorganization for sensory function, with underlying left cortico-talamic and cortico-spinal pathways less severely impaired. Knowledge of the full framework in these conditions is of vital importance for timely patient management; advanced neuroimaging techniques may be considered as prognostic indicators in those cases with extensive involvement of eloquent brain areas.

Impact of Cerebral Revascularization on Pial Collateral Flow in Patients With Unilateral Moyamoya Disease Using Quantitative Magnetic Resonance Angiography.

Moyamoya disease (MMD) is a chronic steno-occlusive disease of the intracranial circulation that depends on neoangiogenesis of collateral vessels to maintain cerebral perfusion and is primarily managed with cerebral revascularization surgery. A quantitative assessment of preoperative and postoperative collateral flow using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA) was used to illustrate the impact of revascularization on cerebral flow distribution. A retrospective review of patients with unilateral MMD who underwent direct, indirect, or combined direct/indirect cerebral revascularization surgery was conducted between 2011 and 2020. Using NOVA, flow was measured at the anterior cerebral artery (ACA), ACA distal to the anterior communicating artery (A2), middle cerebral artery (MCA), posterior cerebral artery (PCA), and PCA distal to the posterior communicating artery (P2). Pial flow (A2 + P2) and collateral flow (ipsilateral [A2 + P2])-(contralateral [A2 + P2]) were measured and compared before and after revascularization surgery. Total hemispheric flow (MCA + A2 + P2) with the addition of the bypass graft flow postoperatively was likewise measured. Thirty-four patients with unilateral MMD underwent cerebral revascularization. Median collateral flow significantly decreased from 68 to 39.5 mL/min (P = .007) after bypass. Hemispheres with maintained measurable bypass signal on postoperative NOVA demonstrated significant reduction in median collateral flow after bypass (P = .002). Median total hemispheric flow significantly increased from 227 mL/min to 247 mL/min (P = .007) after bypass. Only one patient suffered an ipsilateral ischemic stroke, and no patients suffered a hemorrhage during follow-up. NOVA measurements demonstrate a reduction in pial collateral flow and an increase in total hemispheric flow after bypass for MMD, likely representing a decrease in leptomeningeal collateral stress on the distal ACA and PCA territories. Further studies with these measures in larger cohorts may elucidate a role for NOVA in predicting the risk of ischemic and hemorrhagic events in MMD.

Study of Cerebral Hemispheric Lateralization in Stroke and the Arterial Territories Involved in High-risk Patients

Introduction: According to WHO, Stroke is the 2nd leading cause of death and disability after Ischemic heart disease. Prevalence rate of stroke in India varies from 44.45 to 150 per lakh population. Studies have reported a higher frequency of stroke of the left hemisphere. The artery reported to be the most affected is Left Middle Cerebral artery(MCA) followed by Right Middle Cerebral artery. The aim of this study is to determine the side of cerebral hemisphere most affected by stroke and the arterial territories involved in high-risk patients aged above 35 years presenting to the tertiary healthcare centre, as well as to study the sex predilection of stroke. Materials and Methods: A cross-sectional prospective study of 50 high risk stroke patients with Diabetes Mellitus(DM) and /or Hypertension(HTN) presenting to General medicine OPD of a tertiary healthcare centre were investigated with CT/MRI for the side of the cerebral hemisphere affected and the arterial territories involved. The data was tabulated over the course of three months and statistical analysis was carried out. Results: The left cerebral hemisphere was affected in 50%, right in 40% and bilateral involvement was found in 10% patients. Slight predilection of stroke towards the left was seen, however it was not found to be statistically significant (P-value= 0.249). MCA territory was involved in 66% of the patients, Posterior Cerebral Artery(PCA) territory in 8%, Vertebrobasilar Artery(VB) territory in 8%, Anterior Cerebral Artery(ACA) territory in 6% and MCA+ACA in 4%, MCA+VB in 2% and MCA-PCA watershed in 6% patients. Conclusions: We found a slight predilection of stroke towards the left, which was however, not found to be statistically significant. We also found that Middle Cerebral Artery(MCA) territory is the most commonly involved in stroke.

“Worse than hell”: Complex Neuraxial Lesions Resulting in Tetraplegia and Blindness after Polytrauma - Case presentation

Background. Lesions of the vertebral artery (VA) may develop spontaneously or as a result of severe traumatic cervico-cephalic injuries. Most frequent VA injuries (VAI) result from blunt trauma to the spine or may be due to penetrating lesions. VAI plays a significant role in the broader context of cervical spine trauma by providing insights into the vascular aspects of spinal cord injury (SCI). Upper cervical spine fractures and accompanying subluxation, as well as transverse process fractures extending into the artery bone foramen, are associated with an elevated risk of VAI. Clinical case. A 63-year-old female patient with flaccid C4 AIS-A quadriplegia (global motor score 3/100), vertebral myelopathy, neurogenic bladder, sacral pressure sore, and blindness was transferred from the spinal neurosurgical department. The patient fell from the same level and suffered a mild brain concussion and, apparently, a minor cervical SCI on October 1, 2022. She was asymptomatic, then quickly became tetraplegic, and then blindness added on in a few days. She was operated on on October 7, 2022, for a C6 vertebral body fracture and a C5-6 dislocation. The surgical protocol consisted of anterior spinal cord decompression, dislocation reduction, and mixed anterior fusion with bone grafts and fixation screws. Following the traumatic event, a bilateral posterior cerebral artery (PCA) stroke subsequently produced blindness and partial optic atrophy in both eyes. Serial clinical and imaging examinations confirmed the diagnosis: a subacute bilateral occipital stroke and a chronic lacunar lesion in the right thalamus associated with a severe spinal cord lesion. Anticoagulation has partially improved the neurological outcomes of stroke in the PCA territory. Ethical considerations. The patient's next of kin has given written consent to the case study and to use the radiological images related to the case for academic purposes. The personal identity data was anonymized. The presentation of this clinical case has the approval of the ethics commission of TEHBA (no. 40205/01.09.2023). Discussion. The clinical example is notable for the concurrent development of two severely devastating neurological syndromes, quadriplegia, and blindness, which occurred after an initially minor cervical trauma and progressed gradually over a few days. VA lesions after cervical trauma are considered rare, and the diagnosis is difficult because the vast majority of individuals do not exhibit cerebral neurological symptoms (due to the collateral compensatory blood supply from the circle of Willis). Most of the patients with bilateral or dominant VA occlusions are symptomatic, with rapid (and possibly fatal) ischemic damage to the encephalon, cerebellum, or brainstem. The detection and tracking of evolutionary tendencies required a series of clinical tests, including fundoscopy, and imaging procedures, including native CT, MRI, and MR angiography scans of the brain and spine. Conclusions. Although VAI is a rare complication, in every polytrauma patient with head and neck trauma, VA damage should be suspected. Careful clinical and imaging monitoring through detailed serial imaging procedures must be performed for every person with severe cranio-cervical trauma. The clinical example emphasizes the importance of the interprofessional team's participation in the patient's care.

Cerebral microcirculatory pulse wave propagation and pulse wave amplitude mapping in retrospectively gated MRI

To analyze cerebral arteriovenous pulse propagation and to generate phase-resolved pulse amplitude maps from a fast gradient-echo sequence offering flow-related enhancement (FREE). Brain MRI was performed using a balanced steady-state free precession sequence at 3T followed by retrospective k-space gating. The time interval of the pulse wave between anterior-, middle- and posterior cerebral artery territories and the superior sagittal sinus were calculated and compared between and older and younger groups within 24 healthy volunteers. Pulse amplitude maps were generated and compared to pseudo-Continuous Arterial Spin Labeling (pCASL) MRI maps by voxel-wise Pearson correlation, Sørensen-Dice maps and in regards to signal contrast. The arteriovenous delays between all vascular territories and the superior sagittal sinus were significantly shorter in the older age group (11 individuals, ≥ 31 years) ranging between 169 ± 112 and 246 ± 299 ms versus 286 ± 244 to 419 ± 299 ms in the younger age group (13 individuals) (P ≤ 0.04). The voxel-wise pulse wave amplitude values and perfusion-weighted pCASL values correlated significantly (Pearson-r = 0.33, P < 0.01). Mean Dice overlaps of high (gray) and low (white matter) regions were 73 ± 3% and 59 ± 5%. No differences in image contrast were seen in the whole brain and the white matter, but significantly higher mean contrast of 0.73 ± 0.23% in cortical gray matter in FREE-MRI compared to 0.52 ± 0.12% in pCASL-MRI (P = 0.01). The dynamic information of flow-related enhancement allows analysis of the cerebral pulse wave propagation potentially providing information about the (micro)circulation on a regional level. However, the pulse wave amplitude reveals weaknesses in comparison to true perfusion-weighting and could rather be used to calculate a pulsatility index.

The ivy sign as a radiological marker for follow-up of postoperative cerebral perfusion status in adult moyamoya disease.

Little is known about the relationship between postoperative changes in cerebral perfusion and the ivy sign representing leptomeningeal collateral burden in moyamoya disease (MMD). This study aimed to investigate the usefulness of the ivy sign in evaluating cerebral perfusion status following bypass surgery in patients with adult MMD. Two hundred thirty-three hemispheres in 192 patients with adult MMD undergoing combined bypass between 2010 and 2018 were retrospectively enrolled. The ivy sign was represented as the ivy score on FLAIR MRI in each territory of the anterior, middle, and posterior cerebral arteries. Ivy scores, as well as clinical and hemodynamic states on SPECT, were semiquantitatively compared both preoperatively and at 6 months after surgery. Clinical status improved at 6 months after surgery (p < 0.01). On average, ivy scores in whole and individual territories were decreased at 6 months (all p values < 0.01). Cerebral blood flow (CBF) postoperatively improved in three individual vascular territories (all p values ≤ 0.03) except for the posterior cerebral artery territory (PCAt), and cerebrovascular reserve (CVR) improved in those areas (all p values ≤ 0.04) except for the PCAt. Postoperative changes in ivy scores and CBF were inversely correlated in all territories (p ≤ 0.02), except for the PCAt. Furthermore, changes in ivy scores and CVR were only correlated in the posterior half of the middle cerebral artery territory (p = 0.01). The ivy sign was significantly decreased after bypass surgery, which was well correlated with postoperative hemodynamic improvement in the anterior circulation territories. The ivy sign is believed to be a useful radiological marker for postoperative follow-up of cerebral perfusion status.

Long-term prognostic value of [15O]H2O PET imaging in patients suspected for cerebral hemodynamic insufficiency

ObjectivesQuantitative regional cerebral perfusion (rCBF) measurements using [15O]H2O PET with arterial cannulation and acetazolamide (ACZ) challenge have been reserved to identify high-risk patients that are candidates for by-pass operation. We aimed to assess the prognostic value of various parameters in quantitative [15O]H2O PET measurements in patients not subsequently undergoing surgery. MethodsWe identified 32 eligible patients who underwent [15O]H2O brain PET imaging for suspicion of hemodynamic insufficiency between 2009 and 2020. Cerebrovascular events were defined as new ischemic lesions on MRI, stroke, transient ischemic attack, vascular dementia. Follow-up period was 91 months (range: 26-146). rCBF before (rCBFbase) and after (rCBFacz) ACZ challenge and the relative increase (CVR), were examined in the anterior (ACA), middle (MCA), and posterior (PCA) cerebral artery territories of the affected hemisphere, and the most recent MRI scans were scored for infarcts and white matter lesions. ResultsReceiver operating characteristic (ROC) curve analysis showed higher prognostic accuracy for rCBFacz(AUC:0.82) compared to CVR (AUC:0.72) and rCBFbase (AUC:0.77). ROC AUC, optimal thresholds (and corresponding sensitivity/specificity/accuracy) for rCBFacz after ACZ in individual territories were 0.79 and 37.8 mL 100g−1 min−1 (0.81/0.63/0.72) for the ACA, 0.84 and 32 mL 100g−1 min−1 (0.81/0.75/0.78) for the MCA, and 0.70 and 43.9 ml/(mL 100g−1 min−1 (0.81/0.43/0,62) for the PCA. Kaplan Meier survival curve showed longer event-free survival in patients with rCBFacz below cut-off (p=0.007). In multivariate analysis rCBFacz remained a significant predictor when correcting for age. ConclusionQuantitative rCBF measurements after ACZ challenge with [15O]H2O PET provided high prognostic value for future cerebrovascular events.

Posterior cerebral territory ischemia in pediatric moyamoya: Surgical techniques and long-term clinical and radiographic outcomes.

To describe a surgical technique for posterior cerebral revascularization in pediatric patients with moyamoya arteriopathy. Here, we describe the clinical characteristics, surgical indications, operative techniques, and clinical and radiographic outcomes in a series of pediatric patients with moyamoya disease affecting the posterior cerebral artery (PCA) territory. A retrospective single-center series of all pediatric patients with moyamoya disease who presented to our institute between July 2009 through August 2019 were reviewed. The clinical characteristics, surgical indications, operative techniques, and long-term clinical and radiographic outcomes of pediatric moyamoya patients with PCA territory ischemia were collected and analyzed. A total of 10 PCA revascularization procedures were performed in 9 patients, 5 female, ages 1 to 11.1years (average 5.2years). Complications included 1 stroke, with no infections, hemorrhages, seizures, or deaths. One patient had less than 1year of radiographic and clinical follow-up. In 8 of 9 patients with at least 1year of radiographic follow-up, there was engraftment of surgical vessels present in all cases. No new strokes were identified on long-term follow-up despite the radiographic progression of the disease. In the 8 cases available for analysis, the average follow-up was 50.8months with a range of 12 to 117months. PCA territory ischemia in patients with progressive moyamoya disease can be surgically treated with indirect revascularization. Here, we describe our experience with PCA revascularization procedures for moyamoya disease, including pial pericranial dural (PiPeD) revascularization and pial synangiosis utilizing the occipital artery. These surgical options may be useful for decreasing the risk of stroke in pediatric moyamoya patients with severe posterior circulation disease.

Abstract 18886: Rare but Fatal: Thrombus Formation and Cerebral Infarction Following Atrial Fibrillation Ablation

Introduction: Atrial fibrillation (AF) ablation has become increasingly common as a first line treatment for young, healthy patients and recurrent AF. While the procedures are effective and safe with a mortality rate of &lt;0.1%, it can be associated with fatal complications. Case Presentation: A 74-year-old male with a history of AF status post epicardial ablation, ascending and thoracic aortic aneurysm, hypertension, dilated cardiomyopathy, sick sinus syndrome and alcohol use presented with left hemiparesis and left sided facial droop. He had undergone radiofrequency ablation about 3 weeks prior. Initial evaluation for stroke with computed tomography (CT) of head and CT angiography (CTA) of head/neck was negative. He was intubated for airway protection. Upon insertion of the nasogastric tube, it had dark blood concerning for an upper gastrointestinal bleed. The hospital course was complicated by sinus bradycardia and severe hypotension requiring dopamine and norepinephrine infusions. Repeat CTA head/neck demonstrated new evolving infarcts in the left middle cerebral artery (MCA), left posterior cerebral artery and right MCA territories. During an esophagogastroduodenoscopy to rule out atrioesophageal fistula, patient had a vasovagal episode which resolved with epinephrine. Subsequent transesophageal echocardiogram (TEE) demonstrated an echogenic long protruding thrombus extending across the iatrogenic atrial septal defect from the right atrium to the posterior wall of the left atrium, attached near the ostium of the right lower pulmonary vein. Repeat CT head multiple new areas concerning for developing infarctions and pneumocephalus. Given his overall grim prognosis, the patient was transitioned to comfort care. Conclusions: As ablative procedures for management of AF become more prevalent, it is imperative to maintain a high clinical suspicion for rare but fatal complications which require prompt diagnosis and early aggressive management.

Abstract 089: A Case of Complicated Dissection: Vertebral Artery Sacrifice for Recurrent Stroke Prevention

Introduction Posterior circulation strokes account for 20% of ischemic strokes (1). Optimal management for posterior circulation strokes has been studied less than for anterior circulation strokes (2). Endovascular parent vessel sacrifice is an established technique used to treat vascular pathologies. There is limited evidence for parent artery sacrifice for recurrent strokes and there is no current guideline for standard of care. Methods '‐ Results 51‐year‐old gentleman with history of tobacco use presented with left homonymous hemianopsia, onset 1.5 hours prior to arrival. CT brain showed no bleed and patient received IV tissue‐plasminogen activator (tPA). CT angiography (CTA) demonstrated occlusion of the right posterior cerebral artery (PCA) and dissection of the left vertebral artery (V2 segment) with distal reconstitution. He underwent emergent thrombectomy for right P2 thrombus with complete reperfusion TICI 3 (Thrombolysis in Cerebral Infarction Score). Less than 24 hours later, he developed a right homonymous hemianopsia, and was found to have a new occlusion of the left P1 segment of the left PCA. Emergent thrombectomy was performed with complete reperfusion (TICI3). MRI brain demonstrated bilateral PCA territory infarcts. Within 12 hours of the second thrombectomy, his neurological exam deteriorated, and interval imaging revealed a basilar trunk thrombus, for which he underwent a successful endovascular thrombectomy complete reperfusion (TICI3). His antiplatelet regimen was optimized with Aspirin. Heparin was considered as treatment but was not provided because of the hemorrhagic conversion of his ischemic strokes. Given the persistent recurrence of thromboemboli in the posterior circulation despite being on optimal medical management, and evidence of hemorrhagic conversion, a decision was made to perform endovascular coil embolization of the left vertebral artery V2 segment at the site of dissection. Angiographic imaging demonstrated antegrade blood flow through the dissection as the source of recurrent embolic strokes. Six Stryker Target coils were deployed spanning the region of dissection within the left V2 segment via a right radial access with the guide catheter in the right vertebral artery. Post coil embolization angiographic runs demonstrated complete occlusion of the left vertebral V2 segment at the region of dissection which was confirmed via a left vertebral injection from a left femoral arterial access. There was preservation of ascending cervical collaterals beyond the dissection with patency of the contralateral vertebral artery supplying the intracranial circulation. Following embolization, repeat imaging showed no new infarcts and no new or worsening hemorrhage. He was continued on Aspirin monotherapy. It is notable that though his neurological exam deteriorated during each recurrent thromboembolic event, his neurologic exam at the time of discharge significantly improved with NIHSS of 3. He is currently being followed at our neuroscience institute. Conclusion Cervical arterial dissections pose increased risk for ischemic strokes (3). Vertebral artery dissection accounts for approximately 2%, of which, 10‐25% occur in middle‐aged and younger patients (4). This is a case of a young patient that exemplifies a successful role for vertebral artery sacrifice with coil embolization to prevent recurrent thromboembolic posterior circulation strokes. However controlled studies are needed for safety and efficacy of these interventions.

Abstract 104: Fetal Posterior Cerebral Artery (PCA) Occlusion from Occluded Cavernous ICA Stent

Introduction Posterior Cerebral Artery (PCA) is a medium vessel occlusion (MVO) which is 5‐10% of all acute ischemic events. Safety and efficacy of mechanical thrombectomy in posterior circulation MVO is unclear compared to medical treatment only (1). There is concern that fragility of distal, smaller vessels may have an increased risk of procedural complications (e.g., arterial dissection and or perforations). More people are getting flow divertors over the years and rate of flow diverter of ICA occlusion is 0.05%‐0.08% (2). Here we present a case of embolic fetal PCA stroke with ICA stent occlusion. Methods We report a case of fetal origin posterior cerebral artery occlusion from ICA with literature search of Pubmed. Results 77 years old female with left cavernous‐ICA stent presented from a rehab facility with complaints of word finding difficulty, confusion, right hemiparesis, right sided neglect, and visual disturbance. In the emergency department (ED), her NIHSS was 28. ED presentation was 2.5 hrs after the last known well (LKW). Of note, patient had a with left cavernous‐ICA stent placement a month before the presentation and was noncompliant to antiplatelets. CT head was negative for intracranial bleeding and ASPECT score was 7. CT angiography head and neck was obtained, showing new complete interval occlusion of the intracranial extradural left ICA with reconstitution of distal branches through anterior communicating artery. Patient received IV thrombolytics, intubated for airway protection and was transferred to a comprehensive stroke center for possible mechanical thrombectomy. Time of the arrival was approximately 6 hours after the LKW, reexamination was hindered by the sedation and intubation but was concerning for possible PCA occlusion rather than ICA occlusion. As the localization of ischemic area was unclear, CT perfusion (CTP) was obtained. CTP showed 27 ml penumbra without core infarct in left PCA territory. As fetal origin of left PCA from ICA is occluded, without ability to access through occluded stent, noted risk of left ICA complications with attempts to recanalize stent for noted PCA hypoperfusion outweigh the benefits. With the exam improvement post thrombolytics administration and small penumbra, mechanical thrombectomy was not indicated. Conclusion In acute large vessel occlusion, utility of CT perfusion (CTP) usually recommended after 6 hours from last well known. In this case, patient presented within the 6 hours but the reexamination post thrombolytics was not localizing to suggest large vessel occlusion (LVO) and the territory at risk was unclear. We described a left intracranial ICA flow diversion occlusion without anterior circulation ischemia and left PCA ischemia demonstrated. In this case, CTP was employed to differentiate the territory at risk for triage to appropriate intervention, to differentiate the LVO vs MVO.

Memory, Executive, and Intellectual Functions in Adults with Moyamoya Disease

Cognitive function can decline in adults with moyamoya disease (MMD). Memory, which is an essential but complex and multifaceted function, underpins executive and intellectual functions. However, the relationship between memory and executive or intellectual functions in adults with MMD has not been well studied. The relationship between memory and cerebral blood flow has also not been elucidated. This study investigated correlations between memory, executive function, and intellectual function, and associations between cerebral blood flow and memory in adults with MMD. Memory, executive function, and intellectual function were assessed using the Wechsler Memory Scale-Revised (WMS-R), Frontal Assessment Battery (FAB), and Wechsler Adult Intelligence Scale (WAIS) third or fourth edition, respectively, in 31 adults with MMD. Cerebral blood flow was measured with iodine 123I-iodoamphetamine single-photon emission computed tomography. WMS-R scores correlated significantly with total FAB and WAIS scores before and after revascularization. Cerebral blood flow in the left posterior cerebral artery territory correlated positively with WMS-R and WAIS scores pre- and postoperatively. Postoperative cerebrovascular reserves of the right cerebellum, pons, and vermis were positively associated with visual memory, and postoperative cerebrovascular reserve of the pons was also associated with general memory. Memory function correlates with executive and intellectual functions in adults with MMD. The FAB, which requires about 10min to administer, might be useful to screen for memory dysfunction. Memory might be vulnerable to hypoperfusion in the posterior cerebral artery territory among adults with MMD. Postoperative cerebrovascular reserve might help predict memory dysfunction in adults with MMD.

Walk Your Dizzy Patients! Gait Assessment as a Screening Tool for Posterior Circulation Stroke (S3.001)

<h3>Objective:</h3> To determine if objective gait abnormality (OGA) might be used as a cost-effective screening tool in the acute presentation of posterior circulation stroke (PSC). <h3>Background:</h3> The National Institutes of Health Stroke Scale (NIHSS) is less robust for patients with PCS due to lack of inclusion of signs and symptoms localizing to the posterior fossa. We previously showed that OGA was the most common presenting feature in this population. Our present hypothesis was that association with OGA would be greater in PCS patients than posterior stroke mimics, especially in those presenting with dizziness or subjective gait abnormality (SGA). <h3>Design/Methods:</h3> We completed a case-control study to determine odds of OGA in PCS patients and mimics, reported with confidence intervals(CI), sensitivity(SE), specificity(SP), positive predictive value(PPV), and negative predictive value(NPV). We defined PCS cases as acute ischemic strokes isolated to the posterior cerebral, basilar, or vertebral artery territories. Mimics were defined as acutely vertiginous patients from other causes. <h3>Results:</h3> We identified 82 PCS patients (average age=67, 51% female) and 104 mimics (average age=63, 51%female) with gait assessment on arrival. OGA was documented in 69/82(84.1%) PCS cases vs. 18/104(17.3%) mimics (OR=25.4, CI=11.62–55.35, SE84%, SP82%, PPV79%, NPV87%). Stratified by dizziness, OGA was documented in 38/44(86%) PCS cases vs. 18/104(17.3%) mimics (OR=30.3, CI=11.13–82.23, SE86%, SP83%, PPV68%, NPV94%). Stratified by SGA, OGA was documented in 48/52(92%) PCS cases vs. 16/74(21.6%) mimics (OR=43.5, CI=13.63–138.83, SE92%, SP78%, PPV75%, NPV94%). <h3>Conclusions:</h3> Patients at NYU Langone Hospitals with PCS were 25.4× more likely to have OGA than mimics, and 30.3× or 43.5× more likely to have OGA when presenting with dizziness or SGA. While SP and PPV remained low (&lt;90%), NPV rose to 94% in patients with dizziness and SGA on admission. Gait assessment can be used as a cost-effective screening tool to rule out PCS on arrival. Prospective studies should be accomplished prior to recommendation. <b>Disclosure:</b> Dr. Smith has nothing to disclose. Dr. Valdes has received research support from a T32 NIH Grant. Dr. Torres has nothing to disclose. Dr. Melmed has nothing to disclose.

Middle cerebral artery dynamic cerebral autoregulation is impaired by infarctions in the anterior but not the posterior cerebral artery territory in patients with mild strokes.

The aim of this study was to ascertain whether dynamic cerebral autoregulation (CA) in the middle cerebral artery (MCA) is disturbed by cerebral infarctions outside the MCA territory. We estimated transfer function parameters gain and phase from simultaneous recordings of spontaneous oscillation in blood pressure and MCA cerebral blood flow velocity in 10 consecutive patients with isolated anterior cerebral artery (ACA) infarctions and in 22 consecutive patients with isolated posterior cerebral artery (PCA) infarctions. All ACA infarctions were in the motor, premotor, or supplementary motor cortex areas and presented with pronounced leg hemiparesis. Twenty-eight age- and sex-matched healthy subjects served as controls. Compared to controls, phase was significantly reduced in the MCA ipsilateral to the lesion site and in the contralateral MCA (unaffected hemisphere) in the very low (0.02-0.07 Hz) and low (0.07-0.15 Hz) frequency ranges in the ACA infarctions but not in the PCA infarctions. Gain was reduced only in the very low frequency range in the MCA contralateral to the ACA lesion site. Systemic factors were unrelated to phase and gain results. Bilateral impairment of MCA dynamic CA in patients with a unilateral ACA infarction is frequent.

Prevalence and Incidence of Carotid-Fetal-Posterior Syndrome

Introduction: Carotid-fetal-posterior (CFP) syndrome is a posterior cerebral artery (PCA) territory ischemic stroke/TIA caused by symptomatic ≥50% carotid stenosis or occlusion via fetal posterior communicating artery. We aimed to assess the incidence of CFP syndrome and prevalence of CFP syndrome among symptomatic ≥50% carotid stenosis or occlusion as these are unknown. Methods: We reassessed consecutive CTAs from 4,042 persons and included locally admitted patients with ≥50% carotid stenosis or occlusion. These were assessed for symptoms and signs of possible posterior circulation stroke/TIA (suspicion of CFP syndrome). Among these, those with unilateral PCA territory stroke/TIA, ipsilateral stenosis, and fetal/fetal-type PCA were considered CFP syndrome. Results: We included 208 locally admitted patients with ≥50% carotid stenosis or occlusion; 33 (16%) patients had suspicion of CFP syndrome, of which 3 (9%) had CFP syndrome. The prevalence of CFP syndrome was 2.9% of symptomatic ≥50% carotid stenosis or occlusion; incidence was 4.23 per 1,000,000 person-years. Also, we found a lower prevalence of CFP syndrome (0.9%, p = 0.047) among referred patients with symptomatic ≥50% carotid stenosis or occlusion than among locally admitted patients with symptomatic ≥50% carotid stenosis or occlusion. Discussion/Conclusion: CFP syndrome has a low incidence and low prevalence among symptomatic carotid stenosis cases. Given lower prevalence of CFP syndrome among referred cases than local, CFP syndrome seems susceptible to underdiagnosis. On the other hand, few cases with suspicion of CFP syndrome had CFP syndrome, why CFP syndrome also seems susceptible to overdiagnosis if detailed assessment is not employed.

Spreading depolarization and angiographic spasm are separate mediators of delayed infarcts.

In DISCHARGE-1, a recent Phase III diagnostic trial in aneurysmal subarachnoid haemorrhage patients, spreading depolarization variables were found to be an independent real-time biomarker of delayed cerebral ischaemia. We here investigated based on prospectively collected data from DISCHARGE-1 whether delayed infarcts in the anterior, middle, or posterior cerebral artery territories correlate with (i) extravascular blood volumes; (ii) predefined spreading depolarization variables, or proximal vasospasm assessed by either (iii) digital subtraction angiography or (iv) transcranial Doppler-sonography; and whether spreading depolarizations and/or vasospasm are mediators between extravascular blood and delayed infarcts. Relationships between variable groups were analysed using Spearman correlations in 136 patients. Thereafter, principal component analyses were performed for each variable group. Obtained components were included in path models with a priori defined structure. In the first path model, we only included spreading depolarization variables, as our primary interest was to investigate spreading depolarizations. Standardised path coefficients were 0.22 for the path from extravascular bloodcomponent to depolarizationcomponent (P = 0.010); and 0.44 for the path from depolarizationcomponent to the first principal component of delayed infarct volume (P < 0.001); but only 0.07 for the direct path from bloodcomponent to delayed infarctcomponent (P = 0.36). Thus, the role of spreading depolarizations as a mediator between blood and delayed infarcts was confirmed. In the principal component analysis of extravascular blood volume, intraventricular haemorrhage was not represented in the first component. Therefore, based on the correlation analyses, we also constructed another path model with bloodcomponent without intraventricular haemorrhage as first and intraventricular haemorrhage as second extrinsic variable. We found two paths, one from (subarachnoid) bloodcomponent to delayed infarctcomponent with depolarizationcomponent as mediator (path coefficients from bloodcomponent to depolarizationcomponent = 0.23, P = 0.03; path coefficients from depolarizationcomponent to delayed infarctcomponent = 0.29, P = 0.002), and one from intraventricular haemorrhage to delayed infarctcomponent with angiographic vasospasmcomponent as mediator variable (path coefficients from intraventricular haemorrhage to vasospasmcomponent = 0.24, P = 0.03; path coefficients from vasospasmcomponent to delayed infarctcomponent = 0.35, P < 0.001). Human autopsy studies shaped the hypothesis that blood clots on the cortex surface suffice to cause delayed infarcts beneath the clots. Experimentally, clot-released factors induce cortical spreading depolarizations that trigger (i) neuronal cytotoxic oedema and (ii) spreading ischaemia. The statistical mediator role of spreading depolarization variables between subarachnoid blood volume and delayed infarct volume supports this pathogenetic concept. We did not find that angiographic vasospasm triggers spreading depolarizations, but angiographic vasospasm contributed to delayed infarct volume. This could possibly result from enhancement of spreading depolarization-induced spreading ischaemia by reduced upstream blood supply.

Abstract Number ‐ 111: Endovascular embolization of traumatic vessel injury using n‐butyl cyanoacrylate: A case series

Introduction There is limited evidence on the use of N‐butyl cyanoacrylate (n‐BCA) liquid embolic in endovascular embolization of traumatic face and neck vessel injuries. We sought to investigate the safety and effectiveness of n‐BCA in treating traumatic vessel injuries. Methods In a prospectively maintained database, we retrospectively analyzed consecutive patients who presented with a vessel injury caused by either a penetrating or blunt injury in a large academic Level 1 trauma center between April 2021 and July 2022. We included patients aged ≥ 18 years with any vessel injury in the face and neck circulation. The primary endpoint was effectiveness of n‐BCA by immediate control of the active bleeding post‐embolization. Results A total of 10 patients required neuro‐endovascular embolization of traumatic vessel injury via n‐BCA. The mean age of patients was 41.10 (95%CI 28.41, 53.79), with a male predominance (n = 8, 80.0%). The mean Glasgow Coma Scale score on presentation was 10 (95% CI 6.20, 14.40). One patient had concomitant brain injury having subdural and subarachnoid hemorrhages. The mean score for Biffl classification was 5.00. Eight patients suffered penetrating gunshot wound injuries, and two patients suffered blunt injuries. Injured vessels included facial artery (n = 4, 40.0%), buccal branch artery (n = 2, 20.0%), internal maxillary artery (n = 2, 20.0%), cervical segment of the internal carotid artery (n = 1, 10.0%), and the V2 segment of the vertebral artery (n = 1, 10.0%). All patients were successfully treated with 2:1 n‐BCA to ethiodol with immediate extravasation control. Balloon guide catheter was used in 3 patients (30.0%). There was no recurrence of bleeding via vessel imaging or need for retreatment. One patient died in‐hospital (10.0%). Most patients were discharged home (n = 5, 50.0%), one discharged home with day rehab (n = 1, 10.0%), and one to an acute rehab facility (n = 1, 10.0%). One patient developed a right posterior cerebral artery territory infarct with hemorrhagic transformation post‐embolization. Conclusions To the best of our knowledge, this is the first study demonstrating the safety and effectiveness of n‐BCA liquid embolic in traumatic vessel injuries, especially penetrating gunshot wound injuries. Further research is needed to investigate the safety and efficacy in this population.