CT Imaging Computed Tomography/Computed Tomography Angiography/Perfusion in Acute Ischemic Stroke and Vasospasm.

Computed tomography (CT), CT angiography (CTA), and CT perfusion (CTP) play crucial roles in the comprehensive evaluation and management of acute ischemic stroke, aneurysmal subarachnoid hemorrhage (SAH), and vasospasm. CTP provides functional data about cerebral blood flow, allowing radiologists, neurointerventionalists, and stroke neurologists to more accurately delineate the volume of core infarct and ischemic penumbra allowing for patient-specific treatment decisions to be made. CTA and CTP are used in tandem to evaluate for vasospasm associated with aneurysmal SAH and can help provide an insight into the physiologic impact of angiographic vasospasm, better triaging patients for medical and interventional treatment.

Advances in Intraoperative Imaging for Vascular Neurosurgery.

Cerebrovascular surgery has many intraoperative imaging modalities available. Modern technologies include intraoperative digital subtraction angiogram, indocyanine green (ICG) angiography, relative fluorescent measurement with ICG, and ultrasound. Each of these can be used effectively in the treatment of open aneurysm and arteriovenous malformation surgeries, in addition to arteriovenous fistula surgery, and cerebral bypass surgery.

Safety and efficacy of the novel Alpha stent for the treatment of intracranial wide-necked aneurysm.

The Alpha stent is an intracranial closed-cell stent with a unique mesh design to enhance wall apposition. It recently underwent structural modifications to facilitate easier stent deployment. This study aimed to evaluate the safety and efficacy of stent-assisted coil embolization for unruptured intracranial aneurysms using the Alpha stent. Between January 2021 and November 2021, 35 adult patients with 35 unruptured intracranial aneurysms in the distal internal carotid artery were prospectively enrolled. For efficacy outcomes, magnetic resonance angiography at the 6-month follow-up was evaluated using the Raymond-Roy occlusion classification (RROC). The safety outcome evaluated the occurrence of symptomatic procedure-related neurological complications up to 6 months postoperatively. Technical success was achieved in 34/35 (97.1%). Six months postoperatively, aneurysm occlusion showed RROC I in 32/35 (91.4%) and RROC II in 3/35 (8.6%) patients. Procedure-related neurologic complications occurred in one patient (2.9%) who experienced hemiparesis due to acute lacunar infarction, which resulted in a 6-month mRS score of 1. The Alpha stent demonstrated excellent efficacy and safety outcomes in stent-assisted coil embolization of unruptured distal ICA aneurysms. The recent structural modifications allowed for easier stent delivery and deployment.Clinical trial registration number: KCT0005841; registration date: 28/01/2021.

Initial Experiences with the Trenza Embolization Device for the Treatment of Wide-Neck Intracranial Aneurysms: A 12-Patient Case Series.

The Trenza embolization device is a frame coil implant with flow-disruption properties and is a new alternative to treat challenging mid-to-large-sized broad-neck bifurcation or sidewall aneurysms. We conducted an observational single-center retrospective study of 12 consecutive patients treated for 10 unruptured and 2 ruptured 6- to 12-mm broad-neck bifurcation or sidewall aneurysms with the Trenza device during 2022-2023. The median patient age was 64 years (interquartile range, 59-70 years), 58% were women, the median largest aneurysm diameter was 9.6 mm (interquartile range, 7.5-11.9 mm), the median dome-to-neck ratio was 1.8 (interquartile range, 1.6-1.9), the most common aneurysm locations were the anterior communicating artery (33%) and basilar artery tip (33%). After a median follow-up of 6.5 months, adequate aneurysm occlusion was achieved in 83%. There were 3 major ischemic complications (25%), leading to 2 permanent neurologic deficits (17%) and 1 transient neurologic deficit (8%). There was 1 fatal rupture of a treated aneurysm 1.6 months after the index treatment. Two patients were retreated (17%). Ischemic complications occurred in patients after a too-dense coil packing at the base of the aneurysm. No technical issues related to the device were encountered. In summary, an adequate aneurysm occlusion rate was achieved using the Trenza-assisted coiling technique for otherwise challenging mid-to-large-sized broad-neck aneurysms. Ischemic complications seemed to occur following overdense coiling at the base of the aneurysm.

A deep-learning model for intracranial aneurysm detection on CT angiography images in China: a stepwise, multicentre, early-stage clinical validation study.

BACKGROUND: Artificial intelligence (AI) models in real-world implementation are scarce. Our study aimed to develop a CT angiography (CTA)-based AI model for intracranial aneurysm detection, assess how it helps clinicians improve diagnostic performance, and validate its application in real-world clinical implementation. METHODS: We developed a deep-learning model using 16 546 head and neck CTA examination images from 14 517 patients at eight Chinese hospitals. Using an adapted, stepwise implementation and evaluation, 120 certified clinicians from 15 geographically different hospitals were recruited. Initially, the AI model was externally validated with images of 900 digital subtraction angiography-verified CTA cases (examinations) and compared with the performance of 24 clinicians who each viewed 300 of these cases (stage 1). Next, as a further external validation a multi-reader multi-case study enrolled 48 clinicians to individually review 298 digital subtraction angiography-verified CTA cases (stage 2). The clinicians reviewed each CTA examination twice (ie, with and without the AI model), separated by a 4-week washout period. Then, a randomised open-label comparison study enrolled 48 clinicians to assess the acceptance and performance of this AI model (stage 3). Finally, the model was prospectively deployed and validated in 1562 real-world clinical CTA cases. FINDINGS: The AI model in the internal dataset achieved a patient-level diagnostic sensitivity of 0·957 (95% CI 0·939-0·971) and a higher patient-level diagnostic sensitivity than clinicians (0·943 [0·921-0·961] vs 0·658 [0·644-0·672]; p<0·0001) in the external dataset. In the multi-reader multi-case study, the AI-assisted strategy improved clinicians' diagnostic performance both on a per-patient basis (the area under the receiver operating characteristic curves [AUCs]; 0·795 [0·761-0·830] without AI vs 0·878 [0·850-0·906] with AI; p<0·0001) and a per-aneurysm basis (the area under the weighted alternative free-response receiver operating characteristic curves; 0·765 [0·732-0·799] vs 0·865 [0·839-0·891]; p<0·0001). Reading time decreased with the aid of the AI model (87·5 s vs 82·7 s, p<0·0001). In the randomised open-label comparison study, clinicians in the AI-assisted group had a high acceptance of the AI model (92·6% adoption rate), and a higher AUC when compared with the control group (0·858 [95% CI 0·850-0·866] vs 0·789 [0·780-0·799]; p<0·0001). In the prospective study, the AI model had a 0·51% (8/1570) error rate due to poor-quality CTA images and recognition failure. The model had a high negative predictive value of 0·998 (0·994-1·000) and significantly improved the diagnostic performance of clinicians; AUC improved from 0·787 (95% CI 0·766-0·808) to 0·909 (0·894-0·923; p<0·0001) and patient-level sensitivity improved from 0·590 (0·511-0·666) to 0·825 (0·759-0·880; p<0·0001). INTERPRETATION: This AI model demonstrated strong clinical potential for intracranial aneurysm detection with improved clinician diagnostic performance, high acceptance, and practical implementation in real-world clinical cases. FUNDING: National Natural Science Foundation of China. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

Optimizing surgical approaches for anterior communicating artery aneurysms: Development and internal validation of a novel surgical scoring system.

BACKGROUND: The objective was to provide comprehensive preoperative information on both the aneurysm orientation and the side and method of surgical approach for optimal preoperative information and safe clipping using 3D imaging modalities. This was achieved by making an objective risk assessment on the surgical side/method and evaluating its effectiveness with internal validation. MATERIALS AND METHODS: Radiologic data of 61 ACoA aneurysm patients between 2012 and 2020 were retrospectively analyzed. A scoring system based on five criteria; ACoA aneurysm dome orientation, A1 symmetry/control, perforating artery control, A2 trace orientation, and A2 fork symmetry was developed. The system is designed to align with the most common surgical approaches in ACoA aneurysm surgery. The patients were categorized into three groups based on the scoring results to determine the most appropriate surgical method. Group I was recommended, Group II was less recommended, and Group III was least recommended. Internal validation was performed to assess the system's effectiveness. Outcomes and complication rates were statistically evaluated. RESULTS: When the scoring system was utilized, the mean score difference between the first group and the other groups was 2.71 and 4.62, respectively. There was a homogeneous distribution among the groups in terms of age, sex, WFNS, and Fisher scores. Complication occurred in three patients in Group I and nine patients each in Group II and Group III. The further the deviation from the first option, the higher the complication rate (p = 0.016), and a significant cause-effect relationship was identified (p = 0.021). The ROC curve established a cut-off value of 12.5 points for complications and outcomes. CONCLUSION: Our study introduces a new scoring system for ACoA aneurysms, enhancing the use of 3D CTA in daily practice and providing internal validation for the proposed approach. By evaluating objective criteria, this scoring system helps predict surgical risks, prevent complications, and supports personalized evaluation and selection of the surgical approach based on objective criteria.

Modification of Woven Endo-Bridge After Intracranial Aneurysm Treatment: A Methodology for Three-Dimensional Analysis of Shape and Relative Position Changes.

During follow-up of patients treated with WEB devices, shape changes have been observed. The quantitative three-dimensional measurement of the WEB shape modification (WSM) would offer useful information to be studied in association with the anatomical results and try to better understand mechanisms implicated in this modification phenomenon. We present a methodology to quantify the morphology and position of the WEB device in relation to the vascular anatomy. Three-dimensional rotational angiography (3DRA) images of seven aneurysms patients treated with WEBs were used, which also accompanied by a post-treatment 3DRA image and a follow-up 3DRA image. The device was manually segmented, obtaining the 3D models after treatment and at the follow-up. Volume, surface area, height, maximum diameter and WSM ratio of both surfaces were calculated. Position changes were evaluated measuring WEB axis and relative position between post-treatment and follow-up. Changes in WEB volume and surface area were observed with a mean modification of - 5.04 % ( ± 14.19 ) and - 1.68 % ( ± 8.29 ) , respectively. The positional variables also showed differences, mean change of device axis direction was 26.25 % ( ± 24.09 ) and mean change of distance l b was 5.87 % ( ± 10.59 ) . Inter-observer and intra-observer variability analyses did not show differences (ANOVA p > 0.05 ). This methodology allows quantifying the morphological and position changes suffered by the WEB device after treatment, offering new information to be studied in relation to the occurrence of WEB shape modification.

Synthetic interpolated DSA for radiation exposure reduction via gamma variate contrast flow modeling: a retrospective cohort study.

BACKGROUND: Digital subtraction angiography (DSA) yields high cumulative radiation dosages (RD) delivered to patients. We present a temporal interpolation of low frame rate angiograms as a method to reduce cumulative RDs. METHODS: Patients undergoing interventional evaluation and treatment of cerebrovascular vasospasm following subarachnoid hemorrhage were retrospectively identified. DSAs containing pre- and post-intervention runs capturing the full arterial, capillary, and venous phases with at least 16 frames each were selected. Frame rate reduction (FRR) of the original DSAs was performed to 50%, 66%, and 75% of the original frame rate. Missing frames were regenerated by sampling a gamma variate model (GVM) fit to the contrast response curves to the reduced data. A formal reader study was performed to assess the diagnostic accuracy of the "synthetic" studies (sDSA) compared to the original DSA. RESULTS: Thirty-eight studies met inclusion criteria (average RD 1,361.9 mGy). Seven were excluded for differing views, magnifications, or motion. GVMs fit to 50%, 66%, and 75% FRR studies demonstrated average voxel errors of 2.0 ± 2.5% (mean ± standard deviation), 6.5 ± 1.5%, and 27 ± 2%, respectively for anteroposterior projections, 2.0 ± 2.2%, 15.0 ± 3.1%, and 14.8 ± 13.0% for lateral projections, respectively. Reconstructions took 0.51 s/study. Reader studies demonstrated an average rating of 12.8 (95% CI 12.3-13.3) for 75% FRR, 12.7 (12.2-13.2) for 66% FRR and 12.0 (11.5-12.5) for 50% FRR using Subjective Image Grading Scale. Kendall's coefficient of concordance resulted in W = 0.506. CONCLUSION: FRR by 75% combined with GVM reconstruction does not compromise diagnostic quality for the assessment of cerebral vasculature. RELEVANCE STATEMENT: Using this novel algorithm, it is possible to reduce the frame rate of DSA by as much as 75%, with a proportional reduction in radiation exposure, without degrading imaging quality. KEY POINTS: • DSA delivers some of the highest doses of radiation to patients. • Frame rate reduction (FRR) was combined with bolus tracking to interpolate intermediate frames. • This technique provided a 75% FRR with preservation of diagnostic utility as graded by a formal reader study for cerebral angiography performed for the evaluation of cerebral vasospasm. • This approach can be applied to other types of angiography studies.

Preliminary findings on diagnostic performance of computed tomography perfusion images for intracranial arterial stenosis: a retrospective study.

OBJECTIVES: Computed tomographic perfusion (CTP) can play an auxiliary role in the selection of patients with acute ischemic stroke for endovascular treatment. However, data on CTP in non-stroke patients with intracranial arterial stenosis are scarce. We aimed to investigate images in patients with asymptomatic intracranial arterial stenosis to determine the detection accuracy and interpretation time of large/medium-artery stenosis or occlusion when combining computed tomographic angiography (CTA) and CTP images. METHODS: We retrospectively reviewed 39 patients with asymptomatic intracranial arterial stenosis from our hospital database from January 2021 to August 2023 who underwent head CTP, head CTA, and digital subtraction angiography (DSA). Head CTA images were generated from the CTP data, and the diagnostic performance for each artery was assessed. Two readers independently interpreted the CTA images before and after CTP, and the results were analyzed. RESULTS: After adding CTP maps, the accuracy (area under the curve) of diagnosing internal carotid artery (R1: 0.847 vs. 0.907, R2: 0.776 vs. 0.887), middle cerebral artery (R1: 0.934 vs. 0.933, R2: 0.927 vs. 0.981), anterior cerebral artery (R1: 0.625 vs. 0.750, R2: 0.609 vs. 0.750), vertebral artery (R1: 0.743 vs. 0.764, R2: 0.748 vs. 0.846), and posterior cerebral artery (R1: 0.390 vs. 0.575, R2: 0.390 vs. 0.585) occlusions increased for both readers (p < 0.05). Mean interpretation time (R1: 72.4 ± 6.1 s vs. 67.7 ± 6.4 s, R2: 77.7 ± 3.8 s vs. 72.6 ± 4.7 s) decreased when using a combination of both images both readers (p < 0.001). CONCLUSIONS: The addition of CTP images improved the accuracy of interpreting CTA images and reduced the interpretation time in asymptomatic intracranial arterial stenosis. These findings support the use of CTP imaging in patients with asymptomatic intracranial arterial stenosis.

[Radiation Dose Reduction through the Optimization of Mask Images in Cerebral Angiography].

PURPOSE: To verify the effectiveness of optimizing the number of mask images in DSA for radiation dose reduction during cerebral angiography. METHODS: A total of 60 angiography sessions in 2 times for 30 patients performed by the same operator were included in this study. In order to compare the effects of optimization to change the injection delay time of DSA from 1 s to the shortest possible time, the number of mask images, the number of imaging frames, and radiation doses between sessions were compared and analyzed retrospectively. RESULTS: In one DSA run, the number of mask images was decreased from 6 (5-7) to 3 (2-3) frames (p<0.01)/57.1% (median [IQR]/reduction rate), the number of imaging frames was decreased from 34 (32-36) to 32 (29-34) frames (p<0.01)/7.9%, and the radiation dose was decreased from 33 (23-47) to 30 (21-40) mGy (p<0.01)/8.3%. In magnification angiography, the reductions rate was significantly increased. In one angiography session, the number of mask images was decreased from 45 (35-72) to 19 (16-34) frames (p<0.01)/54.6%, the number of imaging frames was decreased from 242 (199-385) to 211 (181-346) frames (p<0.01)/8.3%, the radiation dose of DSA was decreased from 295 (190-341) to 242 (167-305) mGy (p<0.01)/11.6%, and the total radiation dose was decreased from 369 (259-418) to 328 (248-394) mGy (p<0.01)/7.5%. CONCLUSION: Using the shortest possible injection delay time for the number of mask image optimization was an effective radiation dose reduction method.

Trend of cerebral aneurysms over the past two centuries: need for early screening.

OBJECTIVE: Cerebral aneurysms (CAs) are linked to variations in the cerebral basal arterial network (CBAN). This study aimed to find the optimal age for screening to detect brain arterial variations and predict aneurysms before rupture. DESIGN: An observational, quantitative and retrospective research. SETTING: The study analysed 1127 cases of CAs published from 1761 to 1938. Additionally, CT angiography images of 173-patients at the Royal Adelaide Hospital (RAH), South Australia between 2011 and 2019 were examined for the presence and the location of aneurysms in CBAN. PARTICIPANTS: The data were collected from patients at RAH and 407 published sources, including males and females across the entire age range, up to 100 years old. OUTCOME MEASURES AND RESULTS: Data, CAs cases, from 1761 to 1938 included (526 males, 573 females and 28 unknown sexes). The age of these patients varied from 18 months to 89 years (mean age=42, SD=18). Approximately 11.5% of the CAs occurred in patients aged <20 years. Among the 1078 aneurysms whose location was reported, 76% were located in the internal carotid (IC), middle cerebral (MC) and anterior communicating artery complex (AcomAC) regions, while the remaining 24% were in the vertebrobasilar region. Among 173 patients from RAH aged between 18 and 100 years (male=83 and female=90, mean age=60, SD=16), 94% of the CAs were found in the IC, MC and AcomAC regions. The pattern of aneurysm occurrence, as indicated by values at the 25th, 50th and 75th percentiles, along with the minimum and maximum patient ages, has remained consistent from 1761 to 2019. CONCLUSION: The distribution pattern of CAs in relation to sex, age and locations in the CBAN, remained steady over the last 260 years resulting in risk of strokes early in life. Therefore, early screening for CBAN segment variations is advised for stroke prevention if possible.

Hemoglobin in large vessel occlusion: Look further than collaterals.

BACKGROUND: Abnormal hemoglobin (Hb) levels lead to poorer outcomes in ischemic stroke, though the mechanisms remain elusive. We aimed to study the role of Hb on imaging and clinical outcomes, namely on collaterals as it is a known mediator of infarct growth. METHODS: Retrospective cohort study of patients with large vessel occlusion ischemic stroke admitted to our center. Demographics, clinical and imaging variables were collected, particularly baseline hemoglobin, presence of anemia and collateral score. Collaterals were scored from 0 to 3 and defined as poor if 0-1. Multivariable analyses were performed for collateral score and clinical outcomes (3-month mortality and good prognosis). RESULTS: We included 811 patients, 215 (26.5 %) with anemia. Patients with anemia were older, had more comorbidities and more severe strokes. Hemoglobin levels and anemia were not associated with collateral score (OR 0.97, 95 % CI 0.89-1.05, p = 0.414 and OR 0.89, 95 % CI 0.64-1.24, p = 0.487, respectively) nor with poor collaterals (OR 0.96, 95 % CI 0.88-1.05, p = 0.398 and OR 0.86, 95 % CI 0.60-1.23, p = 0.406, respectively). Hb levels were associated with 3-month mortality (OR 0.85, 95 % CI 0.76-0.96, p = 0.008). CONCLUSION: Hemoglobin or anemia were not found to be associated with collateral status. Our results raise further questions regarding the pathophysiology of anemia and outcomes in ischemic stroke, highlighting the need for future research.

Development of Collateral Vessels after Anterior Circulation Large Vessel Occlusion in Pediatric Arterial Ischemic Stroke Relates to Stroke Etiology: A Longitudinal Study.

BACKGROUND AND PURPOSE: The characteristics of large vessel occlusion (LVO) in the acute phase of pediatric arterial ischemic stroke and their natural history according to stroke etiology are poorly explored. This studied aimed at describing the prevalence and the radiological evolution of LVO in pediatric AIS. MATERIALS AND METHODS: This single-center retrospective study included consecutive non-neonate children with acute arterial ischemic stroke, intracranial proximal LVO in the anterior circulation (MCA, anterior cerebral artery, and/or ICA), and clinical and imaging follow-up for at least 18 months, during a 9-year period. RESULTS: Intracranial LVO was observed in 24.8% of patients with anterior circulation arterial ischemic stroke and adequate follow-up (n = 26/105), with a median age of 4.2 years (IQR 0.8-9), sex ratio 1.16. The main stroke etiology associated with LVO was unilateral focal cerebral arteriopathy (n = 12, 46%). During follow-up, a specific pattern of unilateral poststroke anastomotic bridge was observed in 8/26 patients, with the poststroke development of nonperforating collaterals forming a bridge in bypass of the LVO site with visible distal flow, within a median delay of 11 months. The development of unilateral poststroke anastomotic bridge was only observed in patients with unilateral focal cerebral arteriopathy. No patient with this pattern experienced stroke recurrence or further progressive vascular modifications. CONCLUSIONS: After stroke, the development of unilateral poststroke anastomotic bridge is specifically observed in children with focal cerebral arteriopathy, appearing in the first year after stroke. This clinical-radiologic pattern was not associated with stroke recurrence or arterial worsening, differentiating it from progressive intracranial arteriopathy, such as Moyamoya angiopathy.

Vertebral Artery Access Considerations in Coil Embolization of Small Superior Cerebellar Artery Aneurysm.

BACKGROUND: Coiling of small superior cerebellar artery aneurysms (sSCAAs) is challenging. We aimed to describe anatomic considerations in the vertebral and basilar artery (VA and BA) morphology for decision making in the coiling of sSCAAs. METHODS: Eleven patients with sSCAAs (<5 mm) treated at our institution between April 2015 and February 2022 were included to show our concept of deciding access routes in the coiling of sSCAAs. The access route was decided on the basis of VA characteristics, BA curvature, and aneurysm laterality. Adequate aneurysm occlusion on angiography (Raymond-Roy grading scale I and II), good outcome (modified Rankin Score 0-2) at the last follow-up, and adverse outcomes were evaluated. RESULTS: Simple coiling (n = 2), a balloon-assisted technique (n = 3), and stent-assisted technique (n = 6) were selected. At the last follow-up (median 13.0 months), adequate aneurysm occlusion and good outcome were obtained in all 9 patients (n = 10). Adverse outcomes were not observed. When VA dominance was equal, in the straight BA, the microcatheter insertion into the ipsilateral VA to the aneurysm was favorable to form a "fulcrum" on the contralateral side and obtain microcatheter stability. When an aneurysm was on the concave aspect of the curved BA, microcatheter insertion into the ipsilateral VA was favorable. As for the convex aspect's aneurysm location, the microcatheter insertion into the contralateral VA can be favored. Further, we described the VA origin classification as it relates to ease of access from a transradial approach. CONCLUSIONS: Vertebrobasilar morphology may be important in deciding access routes in the coiling of sSCAAs.

Electromagnetic tomographic cerebral angiography.

World Health Organization stated that "Cardiovascular diseases (CVDs) are the leading cause of death globally. Angiography is an important method in diagnostic of CVD. Standard-of-Care methods of angiography, such as X-Ray or CT- or MRI- angiography methods, being accurate and widely adopted in clinical practice, are bulky, expensive and energy in-efficient. X-ray and CT- angiography methods are also potentially hazardous as techniques require the use of ionizing contrast agents. Electromagnetic tomography (EMT) is an emerging medical imaging modality. EMT is applicable for safe functional imaging but suffers from a limited spatial resolution because of relatively large wavelength of electromagnetic radiation as compared to sizes of biological targets of particular interest, such as, for example blood vessels. Novel approach and method, presented in the study is capable to overcome such limitations and provide a mean for a dynamic, on-line EMT angiography. New method of EMT angiography was presented in application to cerebral angiography. Achieved imaging results clearly demonstrate applicability of the method for detecting small cerebral vessels of the diameter as small as 1.3 mm and to distinguish vessels with different dimensions. The technical challenges in the development of angiography capable EMT systems are assessed and discussed.

Non-aneurysmal subarachnoid hemorrhage in aplastic or twig-like middle cerebral artery: A case report and literature review.

BACKGROUND: Aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare vascular anomaly that can cause hemorrhagic and ischemic stroke. Ap/T-MCA can induce aneurysms due to the fragility of the vessel wall, consequently leading to subarachnoid hemorrhage. Herein, we report a case of Ap/T-MCA with subarachnoid hemorrhage without an aneurysm. CASE PRESENTATION: A 67-year-old man presented to our hospital with a sudden onset of headache. Computed tomography of the head revealed subarachnoid hemorrhage (SAH) in the left Sylvian fissure; however, no aneurysm was observed on digital subtraction angiography. Following conservative treatment, follow-up imaging showed no aneurysm or no recurrent stroke. CONCLUSION: Non-aneurysmal SAH is a possible indication of vessel wall fragility in Ap/T-MCA; however, a standardized treatment strategy for this condition remains to be established.

Double microcatheter reduction using partially deployed Atlas stents in treating a large dysplastic MCA bifurcation aneurysm with Y stent assisted coiling.

Treatment of large dysplastic middle cerebral artery (MCA) aneurysms can be challenging.1 2 Catheterization of M2 branches at hyperacute angles often requires an 'around the world' approach/microcatheter reduction, which can be accomplished with rapid pull,3 balloon anchor,4 and stent anchor5 techniques. In this video video 1, Atlas stents (Stryker) are used for double microcatheter reduction along with Y stent assisted coil embolization (Video 1). Steps include (1) catheterization of the more difficult M2 branch with 'around the world' maneuver; (2) reduction/stent deployment; (3) similar catheterization of the second M2 branch; (4) microcatheter reduction/stent deployment; (5) coil embolization (jailed). Important nuances include: (1) low threshold for a staged procedure; (2) awareness of the possibility of stent twisting; (3) jailed coiling. Final views show adequate treatment of the aneurysm dome with stent protection of the dysplastic neck without thromboembolic complications. Given the residual near the base, close angiographic follow-up is important. neurintsurg;16/3/228/V1F1V1Video 1 Technical video demonstrating double stent reduction technique.

Computed tomography angiography in the diagnosis of brain death: Implementation and results in Germany.

BACKGROUND: Computed tomography angiography (CTA) has been investigated as a confirmatory study (CS) for the diagnosis of brain death (BD). International consensus regarding its use, study parameters, and evaluation criteria is lacking. In the German BD guideline, a CTA protocol was first introduced in 2015. METHODS: The authors obtained a comprehensive dataset of all BD examinations in adults from the German organ procurement organization to investigate implementation, results, and impact of CTA on BD determination during the first 4 years. RESULTS: In 5152 patients with clinically absent brain function, 1272 CTA were reported by 676 hospitals. Use of CTA increased from 17.2% of patients in the first year to 29.7% in the final year. CTA replaced other CS such as electroencephalography without increasing overall CS frequency. Technical failure was rare (0.9%); 89.3% of studies were positive. Negative results (9.8%) were more frequent with secondary brain injury, longer duration of the clinical BD syndrome, or unreliable clinical assessment. Median time to diagnosis was longer with CTA (2.6 h) versus other CS (1.6 h). CTA had no differential impact on the rate of confirmed BD and did not improve access of small hospitals to CS for BD determination. CONCLUSIONS: CTA expands the range of available CS for the diagnosis of BD in adults. Real-world evidence from a large cohort confirms usability of the German CTA protocol within the guideline-specified context.

CTA Supplemented by CTP Increases Interrater Reliability and Endovascular Treatment Use in Patients with Aneurysmal SAH.

BACKGROUND AND PURPOSE: Cerebral vasospasm is a common complication of aneurysmal SAH and remains a risk factor for delayed cerebral ischemia and poor outcome. The interrater reliability of CTA in combination with CTP has not been sufficiently studied. We aimed to investigate the reliability of CTA alone and in combination with CTP in the detection of cerebral vasospasm and the decision to initiate endovascular treatment. MATERIALS AND METHODS: This is a retrospective single-center study including patients treated for aneurysmal SAH. Inclusion criteria were a baseline CTA and follow-up imaging including CTP due to suspected vasospasm. Three neuroradiologists were asked to grade 15 intracranial arterial segments in 71 cases using a tripartite scale (no, mild <50%, or severe >50% vasospasm). Raters further evaluated whether endovascular treatment should be indicated. The ratings were performed in 2 stages with a minimum interval of 6 weeks. The first rating included only CTA images, whereas the second rating additionally encompassed CTP images. All raters were blinded to any clinical information of the patients. RESULTS: Interrater reliability for per-segment analysis of vessels was highly variable (κ = 0.16-0.61). We observed a tendency toward higher interrater reliability in proximal vessel segments, except for the ICA. CTP did not improve the reliability for the per-segment analysis. When focusing on senior raters, the addition of CTP images resulted in higher interrater reliability for severe vasospasm (κ = 0.28; 95% CI, 0.10-0.46 versus κ = 0.46; 95% CI, 0.26-0.66) and subsequently higher concordance (κ = 0.23; 95% CI, -0.01-0.46 versus κ = 0.73; 95% CI, 0.55-0.91) for the decision of whether endovascular treatment was indicated. CONCLUSIONS: CTA alone offers only low interrater reliability in the graduation of cerebral vasospasm. However, using CTA in combination with CTP might help, especially senior neuroradiologists, to increase the interrater reliability to identify severe vasospasm following aneurysmal SAH and to increase the reliability regarding endovascular treatment decisions.

Automated evaluation of collateral circulation for outcome prediction in acute ischemic stroke.

INTRODUCTION: The assessment of collateral circulation in acute ischemic stroke management is essential. Modern tools, such as Brainomix's e-CTA, powered by artificial intelligence, provide detailed insights into collateral assessment. This retrospective study aims to identify factors contributing to favorable collateral status and compare outcomes between patients with good collaterals (grade 3) and fair collaterals (grade 0-2). METHOD: This retrospective study included 97 patients admitted to the Stroke Unit at the Hospital de Clínicas of the Federal University of Paraná, Brazil, from September 2021 to January 2023. Comparative analyses involved demographic factors, cardiovascular risk factors, and the combined outcome of mortality and moderate to severe disability at discharge, 30-day, and 90-day follow-ups. RESULTS: Among the 97 cases, 58.8 % showed 'good collaterals' with a grade 3 status. Variables affecting collateral status included age (p = 0.042), neutrophil-lymphocyte ratio (p = 0.005), and initial NIHSS scores (p<0.001). The presence of good collaterals according to e-CTA reduced the odds of death and moderate-severe disability at discharge (p = 0.003; OR 0.27) and at 30 days (p = 0.015; OR 0.33), although this effect diminished at the 90-day mark after multivariate analysis. DISCUSSION: Automated collateral assessment through e-CTA is a valuable tool in acute ischemic stroke evaluation. Good e-CTA collateral score serve as a promising imaging biomarker, guiding informed clinical decisions during Stroke Unit hospitalizations. This study highlights the relationship between collaterals and stroke outcomes and underscores the potential for AI-driven tools to enhance stroke care management.