Mechanical thrombectomy for acute posterior cerebral artery stroke; Feasibility and predictors of outcome.

PURPOSE: The territorial involvement and the clinical benefit of endovascular therapy (EVT) of the posterior cerebral artery (PCA) occlusion may vary between patients. The purpose of this study was to investigate the feasibility of mechanical thrombectomy (MT) in isolated posterior cerebral artery occlusions (IPCAOs) and the prognostic factors of EVT. METHODS: Forty-eight patients with acute PCA occlusion who underwent EVT between Mar 2008 and Apr 2021 from 2 tertiary centers were retrospectively analyzed. Clinical characteristics, imaging and perfusion abnormalities, and angiographic and clinical outcomes were analyzed. Ischemic changes were assessed with the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS). Perfusion abnormalities were assessed using automated software for Tmax volume measurement and identification of Tmax involved in PCA eloquent areas. RESULTS: The IPCAO sites were P1 (n = 17) and P2 (n = 31). Overall successful recanalization (mTICI 2b/3) was achieved in 68.8% (33/48) and excellent outcome (90-day mRS 0-1) in 52.1% (25/48) of the patients. Excellent/non-excellent outcome was associated with male sex (p = 0.036), admission NIHSS (p = 0.002), pc-ASPECTS (p = 0.035), Tmax > 6 s involvement of the midbrain-thalamus (p = 0.008), first-line stent-retriever thrombectomy (p = 0.036), complete recanalization (p = 0.009), and modified first pass effect (FPE, p = 0.047). Tmax>6 s involvement of the midbrain-thalamus was an independent predictor for non-excellent outcome on multivariable analysis. CONCLUSION: Acute stroke from IPCAO may be successfully treated with EVT. Tmax > 6 s involvement of the midbrain-thalamus on perfusion imaging may be a predictor for clinical outcome.

Follow-up evaluation of temporomandibular joints using magnetic resonance imaging after mandibular trauma: Case series analysis of young adult males.

BACKGROUND/AIMS: A relationship between mandibular fractures and traumatic temporomandibular joint (TMJ) conditions has been suggested in many studies. Although magnetic resonance imaging (MRI) is the best option for a TMJ evaluation, few studies have evaluated the TMJ condition after a mandibular fracture using MRI follow-up. The aim of this study was to evaluate the TMJ for post-traumatic conditions following a mandibular fracture using follow-up MRI. MATERIALS AND METHODS: Fourteen TMJs of seven young adult males (aged 19-21 years) with mandibular fractures were analyzed by MRI, and 12 TMJs of six patients were evaluated by follow-up MRI after the trauma. Regarding the intensity of MRI, the pathologic condition of TMJ was classified into acute joint inflammation, marrow edema, and joint space widening. RESULTS: Thirteen joints (92.9%) showed pathologic conditions, including 11 with acute joint inflammation (84.6%), 10 with joint space widening (76.9%), and six with marrow edema (46.2%). Five out of 12 evaluated joints were injected with dexamethasone. Among these, four joints healed within one week, and one healed within one month. Among the seven untreated TMJs, four and one joint healed within one week and one month, respectively, but two joints of one patient did not improve until one month. Although that patient received arthrocentesis, the right joint showed osteoarthritis six months after the trauma. CONCLUSIONS: Most TMJs were acutely damaged due to mandibular trauma and healed within one week to one month. A follow-up examination could be considered at one month after the injury to confirm the possibility of traumatic TMJ disorder, such as osteoarthritis.

Diagnostic assessment of magnetic resonance imaging for patients with intralabyrinthine schwannoma: A systematic review.

OBJECTIVES: Recent advancements in high-resolution imaging have improved the diagnostic assessment of magnetic resonance imaging (MRI) for intralabyrinthine schwannoma (ILS). This systematic review aimed to evaluate the diagnostic performance of MRI for patients with ILS. METHODS: Ovid-MEDLINE and EMBASE databases were searched for related studies on the diagnostic performance of MRI for patients with ILS published up to February 10, 2020. The primary endpoint was the diagnostic performance of MRI for ILS. The quality of the enrolled studies was assessed using tailored questionnaires and the Quality Assessment of Diagnostic Accuracy Studies-2 criteria. RESULTS: Overall, 6 retrospective studies that included 122 patients with ILS from a parent population of 364 were included. The sample size, parent population and its composition, reference standard, detailed parameters of MRI, and even the diagnostic methods varied between the studies. The studies had moderate quality. The sensitivity of combination of T2WI and CE-T1WI was over 90%. Relative sensitivity of T2WI comparative to CE-T1WI ranged from 62% to 100%, and the specificity were 100%. CONCLUSIONS: MRI has acceptable diagnostic performance for ILS. There is a need for well-organized research to reduce the factors causing heterogeneity.

Diagnostic performance of neuromelanin-sensitive magnetic resonance imaging for patients with Parkinson's disease and factor analysis for its heterogeneity: a systematic review and meta-analysis.

OBJECTIVE: To determine the diagnostic performance of neuromelanin-sensitive magnetic resonance imaging discriminating between patients with Parkinson's disease and normal healthy controls and to identify factors causing heterogeneity influencing the diagnostic performance. METHODS: A systematic literature search in the Ovid-MEDLINE and EMBASE databases was performed for studies reporting the relevant topic before February 17, 2020. The pooled sensitivity and specificity values with their 95% confidence intervals were calculated using bivariate random-effects modeling. Subgroup and meta-regression analyses were also performed to determine factors influencing heterogeneity. RESULTS: Twelve articles including 403 patients with Parkinson's disease and 298 control participants were included in this systematic review and meta-analysis. Neuromelanin-sensitive magnetic resonance imaging showed a pooled sensitivity of 89% (95% confidence interval, 86-92%) and a pooled specificity of 83% (95% confidence interval, 76-88%). In the subgroup and meta-regression analysis, a disease duration longer than 5 and 10 years, comparisons using measured volumes instead of signal intensities, a slice thickness in terms of magnetic resonance imaging parameters of more than 2 mm, and semi-/automated segmentation methods instead of manual segmentation improved the diagnostic performance. CONCLUSION: Neuromelanin-sensitive magnetic resonance imaging had a favorable diagnostic performance in discriminating patients with Parkinson's disease from healthy controls. To improve diagnostic accuracy, further investigations directly comparing these heterogeneity-affecting factors and optimizing these parameters are necessary. KEY POINTS: • Neuromelanin-sensitive MRI favorably discriminates patients with Parkinson's disease from healthy controls. • Disease duration, parameters used for comparison, magnetic resonance imaging slice thickness, and segmentation methods affected heterogeneity across the studies.

Diagnostic performance of MRI of post-laminar optic nerve invasion detection in retinoblastoma: A systematic review and meta-analysis.

PURPOSE: Preoperative MRI detection of post-laminar optic nerve invasion (PLONI) offers guidance in assessing the probability of total tumor resection, an estimation of the extent of surgery, and screening of candidates for eye-preserving therapies or neoadjuvant chemotherapies in the patients with retinoblastoma (RB). The purpose of this systematic review and meta-analysis was to evaluate the diagnostic performance of MRI for detecting PLONI in patients with RB and to demonstrate the factors that may influence the diagnostic performance. METHODS: Ovid-MEDLINE and EMBASE databases were searched up to January 11, 2020, for studies identifying the diagnostic performance of MRI for detecting PLONI in patients with RB. The pooled sensitivity and specificity of all studies were calculated followed by meta-regression analysis. RESULTS: Twelve (1240 patients, 1255 enucleated globes) studies were included. The pooled sensitivity was 61%, and the pooled specificity was 88%. Higgins I2 statistic demonstrated moderate heterogeneity in the sensitivity (I2 = 72.23%) and specificity (I2 = 78.11%). Spearman correlation coefficient indicated the presence of a threshold effect. In the meta-regression, higher magnetic field strength (3 T than 1.5 T), performing fat suppression, and thinner slice thickness (< 3 mm) were factors causing heterogeneity and enhancing diagnostic power across the included studies. CONCLUSIONS: MR imaging was demonstrated to have acceptable diagnostic performance in detecting PLONI in patients with RB. The variation in the magnetic field strength and protocols was the main factor behind the heterogeneity across the included studies. Therefore, there is room for developing and optimizing the MR protocols for patients with RB.

Mechanical Thrombectomy for Tandem Vertebrobasilar Stroke: Characteristics and Treatment Outcome.

Background and Purpose- Tandem vertebrobasilar strokes are not well-known causes of posterior circulation stroke. The purpose of this study was to investigate the characteristics and outcome of mechanical thrombectomy in patients with tandem vertebrobasilar stroke. Methods- Acute basilar artery occlusion patients with tandem vertebral artery (VA) stenosis/occlusion who underwent mechanical thrombectomy were retrospectively analyzed. Concomitant tandem VA steno-occlusion was defined as severe stenosis/occlusion of the extracranial VA with impaired flow. Clinical/angiographic characteristics, recanalization rate, procedure time, and clinical outcome were evaluated with comparisons according to the treatment strategy. Results- Tandem vertebrobasilar occlusion was identified in 24.6% (55 of 224) of the acute basilar artery occlusion patients. Overall successful recanalization and good clinical outcome was achieved in 87.2% (48 of 55) and 30.9% (17 of 55) of the patients. There were no significant differences in procedure time, recanalization rate, and clinical outcome in comparisons of the VA access route selection or angioplasty of the tandem VA lesion. Two patients developed short-term recurrent basilar artery occlusion when angioplasty of the tandem VA lesion was not performed. Good clinical outcome was more likely with lower baseline National Institutes of Health Stroke Scale score (odds ratio, 0.87 [95% CI, 0.787-0.961]; P=0.006) and short onset-to-recanalization time (odds ratio, 0.993 [95% CI, 0.987-0.999]; P=0.03). Conclusions- Tandem vertebrobasilar occlusion may be a frequent pathological mechanism of posterior circulation stroke. Good outcome may be achieved by strategic choice of the access route and selective angioplasty of the tandem VA lesion.

Mechanical Thrombectomy in Subtypes of Basilar Artery Occlusion: Relationship to Recanalization Rate and Clinical Outcome.

Background Acute stroke because of basilar artery occlusion (BAO) represents 1% of all ischemic strokes. However, recanalization rates and treatment outcome for the different pathologic subtypes of BAO stroke are not fully understood. Purpose To compare the recanalization rate and clinical outcomes of mechanical thrombectomy in different subtypes of BAO. Materials and Methods Eighty-two patients (46 men and 36 women; mean age, 73 years; age range, 20-90 years; mean age in men, 70 years [age range, 20-90 years]; mean age in women, 75 years [age range; 61-90 years]) with acute BAO who underwent mechanical thrombectomy between March 2010 and December 2017 were retrospectively analyzed. Patients were classified into three groups: embolism without vertebral artery (VA) steno-occlusion (group 1), embolism from tandem VA steno-occlusion (group 2), and in situ atherosclerotic thrombosis (group 3). Clinical and angiographic characteristics, recanalization rate, procedure times, and clinical outcomes were compared between groups by using the Kruskal-Wallis, Pearson χ2, and Fisher exact tests. Results The incidence of BAO according to stroke mechanism were as follows: group 1, n = 34 (41%); group 2, n = 28 (34%), group 3, n = 20 (24%). Overall, successful recanalization (modified Thrombolysis in Cerebral Infarction grade 2b or 3) was achieved in 78% (64 of 82) and favorable outcome (90-day modified Rankin Scale score, 0-2) in 37% (30 of 82) of the patients. The procedure time was shorter in group 1 than in group 2 (49 vs 66 minutes, respectively; P = .01). Group 1 showed a higher successful recanalization rate than group 3 (29 of 34 [85%] vs 11 of 20 [55%], respectively; P = .01). Good clinical outcome rate was higher in group 1 than in group 3 (18 of 34 [53%] vs four of 20 [20%], respectively; P = .02). Conclusion The outcome of mechanical thrombectomy for basilar artery occlusion differs according to the pathologic mechanism of stroke; the best outcomes and recanalization rate occurred in patients with embolism without vertebral artery steno-occlusion. © RSNA, 2019 See also the editorial by Hetts in this issue.

Prognostic Value of Cervical Nodal Necrosis Observed in Preoperative CT and MRI of Patients With Tongue Squamous Cell Carcinoma and Cervical Node Metastases: A Retrospective Study.

OBJECTIVE. The prognosis of tongue squamous cell carcinoma (SCC) with cervical lymph node metastases is poor, and a subset of patients with aggressive disease experiences treatment failure. The current study evaluated the prognostic value of cervical nodal necrosis (CNN) observed on preoperative imaging studies of patients with tongue SCC and cervical node metastases. MATERIALS AND METHODS. We identified patients with tongue SCC who had undergone preoperative neck CT or MRI (or both) and retrospectively reviewed their demographic and clinical data. Patients with metastatic cervical lymph nodes were divided into two groups according to the presence (CNN group) or absence (non-CNN group) of necrosis, and radiologic extranodal extension (ENE) was assessed for all patients. Follow-up biopsy, imaging, and clinical examinations were used to determine survival and treatment failure. Cox proportional hazard regression analyses were performed to determine clinical, demographic, and pathologic factors for survival. RESULTS. Seventy-two patients with a mean follow-up period of 28.4 months were included. The incidence of CNN was 55.6% (40/72). In univariate analysis, patient age, evidence of CNN on preoperative imaging, radiologic ENE, clinical N classification, and overall stage were significantly associated with survival. The multivariate Cox proportional hazard model showed that patient age and CNN on preoperative imaging were independent negative prognostic factors. CONCLUSION. CNN observed on preoperative imaging studies is an independent predictor of a poor prognosis for patients with tongue SCC, and it may serve as a useful imaging biomarker for tailoring individual treatment regimens.

Futile recanalization in patients with basilar artery occlusion: assessment of the underlying etiology and the role of perfusion imaging.

BACKGROUND: Futile recanalization (FR) after endovascular therapy (EVT) is common in basilar artery occlusion (BAO). The purpose of this study was to investigate the predictors of FR in the posterior circulation with an emphasis on the role of perfusion imaging and its relation to the underlying etiology. METHODS: We included BAO patients who had pretreatment perfusion imaging and successful recanalization after EVT. Patients were dichotomized into futile and non-futile groups according to the favorable functional outcome at 90 days (modified Rankin Scale (mRS) 0-3). Perfusion abnormalities were assessed using an automated software for Tmax volume measurement and identification of hypoperfusion area based on Tmax>6 s involvement of the pons-midbrain-thalamus (PMT), cerebellum, and temporo-occipital lobe. RESULTS: Of the 134 enrolled patients, the incidence of FR was 47.8% (64/134). Multivariate logistic analysis showed that a higher National Institutes of Health Stroke Scale (NIHSS) score on admission (adjusted OR (aOR) 1.066; 95% CI 1.011 to 1.125), a longer onset-to-recanalization time (aOR 1.002; 95% CI 1.001 to 1.004), incomplete recanalization (aOR 3.909; 95% CI 1.498 to 10.200), and PMT hypoperfusion (aOR 4.444; 95% CI 1.203 to 16.415) were independent predictors of FR. In patients with embolic occlusion of etiology, PMT hypoperfusion was associated with FR (aOR 8.379; 95% CI 1.377 to 50.994), whereas intracranial atherosclerotic stenosis (ICAS)-related occlusion was not (p=0.587). CONCLUSIONS: In patients with BAO, the likelihood of FR is associated with PMT hypoperfusion on pretreatment perfusion imaging. In particular, PMT hypoperfusion may be used as an imaging predictor of FR in patients with embolic cause of BAO.

Emerging Concept of Intracranial Arterial Diseases: The Role of High Resolution Vessel Wall MRI.

Intracranial arterial disease (ICAD) is a heterogeneous condition characterized by distinct pathologies, including atherosclerosis. Advances in magnetic resonance technology have enabled the visualization of intracranial arteries using high-resolution vessel wall imaging (HR-VWI). This review summarizes the anatomical, embryological, and histological differences between the intracranial and extracranial arteries. Next, we review the heterogeneous pathophysiology of ICAD, including atherosclerosis, moyamoya or RNF213 spectrum disease, intracranial dissection, and vasculitis. We also discuss how advances in HR-VWI can be used to differentiate ICAD etiologies. We emphasize that one should consider clinical presentation and timing of imaging in the absence of pathology-radiology correlation data. Future research should focus on understanding the temporal profile of HR-VWI findings and developing quantitative interpretative approaches to improve the decision-making and management of ICAD.

Automated Detection of Steno-Occlusive Lesion on Time-of-Flight MR Angiography: An Observer Performance Study.

BACKGROUND AND PURPOSE: Intracranial steno-occlusive lesions are responsible for acute ischemic stroke. However, the clinical benefits of artificial intelligence (AI)-based methods for detecting pathologic lesions in intracranial arteries have not been evaluated. We aimed to validate the clinical utility of an AI model for detecting steno-occlusive lesions in the intracranial arteries. MATERIALS AND METHODS: Overall, 138 TOF-MRA images were collected from 2 institutions, which served as internal (n = 62) and external (n = 76) test sets, respectively. Each study was reviewed by 5 radiologists (2 neuroradiologists and 3 radiology residents) to compare the usage and nonusage of our proposed AI model for TOF-MRA interpretation. They identified the steno-occlusive lesions and recorded their reading time. Observer performance was assessed by using the area under the jackknife free-response receiver operating characteristic curve (AUFROC) and reading time for comparison. RESULTS: The average AUFROC for the 5 radiologists demonstrated an improvement from 0.70 without AI to 0.76 with AI (P = .027). Notably, this improvement was most pronounced among the 3 radiology residents, whose performance metrics increased from 0.68 to 0.76 (P = .002). Despite an increased reading time by using AI, there was no significant change among the readings by radiology residents. Moreover, the use of AI resulted in improved interobserver agreement among the reviewers (the intraclass correlation coefficient increased from 0.734 to 0.752). CONCLUSIONS: Our proposed AI model offers a supportive tool for radiologists, potentially enhancing the accuracy of detecting intracranial steno-occlusion lesions on TOF-MRA. Less experienced readers may benefit the most from this model.

Cutting Balloon Angioplasty for Severe In-Stent Restenosis after Carotid Artery Stenting: Long-Term Outcomes and Review of Literature.

PURPOSE: Cutting balloon-percutaneous transluminal angioplasty (CB-PTA) is a feasible treatment option for in-stent restenosis (ISR) after carotid artery stenting (CAS). However, the longterm durability and safety of CB-PTA for ISR after CAS have not been well established. MATERIALS AND METHODS: We retrospectively reviewed medical records of patients with ISR after CAS who had been treated with CB-PTA from 2012 to 2021 in our center. Detailed information of baseline characteristics, periprocedural and long-term outcomes, and follow-up imaging was collected. RESULTS: During 2012-2021, a total of 301 patients underwent CAS. Of which, CB-PTA was performed on 20 lesions exhibiting severe ISR in 18 patients following CAS. No patient had any history of receiving carotid endarterectomy or radiation therapy. These lesions were located at the cervical segment of the internal carotid artery (n=16), proximal external carotid artery (n=1), and distal common carotid artery (n=1). The median time interval between initial CAS and detection of ISR was 390 days (interquartile range 324-666 days). The follow-up period ranged from 9 months to 9 years with a median value of 21 months. Four patients (22.2%) were symptomatic. The average of stenotic degree before and after the procedure was 79.2% and 34.7%, respectively. Out of the 18 patients receiving CB-PTA, 16 (88.9%) did not require additional stenting, and 16 (88.9%) did not experience recurrent ISR during the follow-up period. Two patients who experienced recurrent ISR were successfully treated with CB-PTA and additional stenting. No periprocedural complication was observed in any case. CONCLUSION: Regarding favorable periprocedural and long-term outcomes in our single-center experience, CB-PTA was a feasible and safe option for the treatment of severe ISR after CAS.

Comparison of two automated CT perfusion software packages in patients with ischemic stroke presenting within 24 h of onset.

Background: We compared the ischemic core and hypoperfused tissue volumes estimated by RAPID and JLK-CTP, a newly developed automated computed tomography perfusion (CTP) analysis package. We also assessed agreement between ischemic core volumes by two software packages against early follow-up infarct volumes on diffusion-weighted images (DWI). Methods: This retrospective study analyzed 327 patients admitted to a single stroke center in Korea from January 2021 to May 2023, who underwent CTP scans within 24 h of onset. The concordance correlation coefficient (ρ) and Bland-Altman plots were utilized to compare the volumes of ischemic core and hypoperfused tissue volumes between the software packages. Agreement with early (within 3 h from CTP) follow-up infarct volumes on diffusion-weighted imaging (n = 217) was also evaluated. Results: The mean age was 70.7 ± 13.0 and 137 (41.9%) were female. Ischemic core volumes by JLK-CTP and RAPID at the threshold of relative cerebral blood flow (rCBF) < 30% showed excellent agreement (ρ = 0.958 [95% CI, 0.949 to 0.966]). Excellent agreement was also observed for time to a maximum of the residue function (T max) > 6 s between JLK-CTP and RAPID (ρ = 0.835 [95% CI, 0.806 to 0.863]). Although early follow-up infarct volume showed substantial agreement in both packages (JLK-CTP, ρ = 0.751 and RAPID, ρ = 0.632), ischemic core volumes at the threshold of rCBF <30% tended to overestimate ischemic core volumes. Conclusion: JLK-CTP and RAPID demonstrated remarkable concordance in estimating the volumes of the ischemic core and hypoperfused area based on CTP within 24 h from onset.

Prediction of treatment response after stereotactic radiosurgery of brain metastasis using deep learning and radiomics on longitudinal MRI data.

We developed artificial intelligence models to predict the brain metastasis (BM) treatment response after stereotactic radiosurgery (SRS) using longitudinal magnetic resonance imaging (MRI) data and evaluated prediction accuracy changes according to the number of sequential MRI scans. We included four sequential MRI scans for 194 patients with BM and 369 target lesions for the Developmental dataset. The data were randomly split (8:2 ratio) for training and testing. For external validation, 172 MRI scans from 43 patients with BM and 62 target lesions were additionally enrolled. The maximum axial diameter (Dmax), radiomics, and deep learning (DL) models were generated for comparison. We evaluated the simple convolutional neural network (CNN) model and a gated recurrent unit (Conv-GRU)-based CNN model in the DL arm. The Conv-GRU model performed superior to the simple CNN models. For both datasets, the area under the curve (AUC) was significantly higher for the two-dimensional (2D) Conv-GRU model than for the 3D Conv-GRU, Dmax, and radiomics models. The accuracy of the 2D Conv-GRU model increased with the number of follow-up studies. In conclusion, using longitudinal MRI data, the 2D Conv-GRU model outperformed all other models in predicting the treatment response after SRS of BM.

Brain Frailty and Outcomes of Acute Minor Ischemic Stroke With Large-Vessel Occlusion.

BACKGROUND AND PURPOSE: The influence of imaging features of brain frailty on outcomes were investigated in acute ischemic stroke patients with minor symptoms and large-vessel occlusion (LVO). METHODS: This was a retrospective analysis of a prospective, multicenter, nationwide registry of consecutive patients with acute (within 24 h) minor (National Institutes of Health Stroke Scale score=0-5) ischemic stroke with anterior circulation LVO (acute minor LVO). Brain frailty was stratified according to the presence of an advanced white-matter hyperintensity (WMH) (Fazekas grade 2 or 3), silent/old brain infarct, or cerebral microbleeds. The primary outcome was a composite of stroke, myocardial infarction, and all-cause mortality within 1 year. RESULTS: In total, 1,067 patients (age=67.2±13.1 years [mean±SD], 61.3% males) were analyzed. The proportions of patients according to the numbers of brain frailty burdens were as follows: no burden in 49.2%, one burden in 30.0%, two burdens in 17.3%, and three burdens in 3.5%. In the Cox proportional-hazards analysis, the presence of more brain frailty burdens was associated with a higher risk of 1-year primary outcomes, but after adjusting for clinically relevant variables there were no significant associations between burdens of brain frailty and 1-year vascular outcomes. For individual components of brain frailty, an advanced WMH was independently associated with an increased risk of 1-year primary outcomes (adjusted hazard ratio [aHR]=1.33, 95% confidence interval [CI]=1.03-1.71) and stroke (aHR=1.32, 95% CI=1.00-1.75). CONCLUSIONS: The baseline imaging markers of brain frailty were common in acute minor ischemic stroke patients with LVO. An advanced WMH was the only frailty marker associated with an increased risk of vascular events. Further research is needed into the association between brain frailty and prognosis in patients with acute minor LVO.

A Review of Endovascular Treatment for Posterior Circulation Strokes.

Mechanical thrombectomy for acute posterior circulation strokes (PCSs) is recommended based on evidence from anterior circulation strokes (ACSs). Two recent randomized controlled trials showed that endovascular treatment (EVT) leads to better functional outcomes than those of the best medical care. However, many studies have shown that patients undergoing PC-EVT have a higher rate of futile recanalization than those undergoing AC-EVT. The characteristics and outcomes of PC-EVT may differ according to the pathological mechanisms, including cardioembolism, intracranial atherosclerosis, and tandem vertebrobasilar occlusion. We reviewed PC-EVT outcomes reported in recent studies and discussed technical considerations for maximizing treatment efficacy according to the etiology of a PCS.

Effect of a vertical incision on postoperative swelling after an impacted mandibular third molar extraction: two cases with split-mouth designed magnetic resonance imaging analysis.

This study examined the effects of a vertical incision on postoperative edema after third molar extraction. The study design was that of a comparative split-mouth approach. Evaluation was performed via magnetic resonance imaging (MRI). Two patients with homogeneous bilateral impacted mandibular third molars were enrolled. These patients underwent facial MRI within 24 hours after simultaneous extraction surgery. Modified triangular flap and enveloped flap incisions were made. Postoperative edema was evaluated by MRI and was assessed according to anatomical space. The two pairs of homogeneous extractions demonstrated that vertical incisions were associated qualitatively and quantitatively with extensive postoperative edema. The edema associated with these incisions spread toward the buccal space, beyond the buccinator muscle. In conclusion, a vertical incision with mandibular third molar extraction was related to edema in the buccal space and the fascial space, which contributed to clinical facial swelling.

Basilar tip morphology: impact on mechanical thrombectomy for acute distal basilar artery occlusion.

BACKGROUND: The morphology of the basilar artery tip (BAT) varies between patients. The morphologic anatomy of the BAT could affect the efficacy of mechanical thrombectomy (MT). METHODS: 108 patients with acute distal basilar artery occlusion (dBAO) who underwent MT from January 2013 to December 2021 were retrospectively analyzed. These patients were divided into two groups based on their BAT morphology: those with symmetrical cranial or caudal fusion of the BAT (symmetric group) and those with asymmetrical fusion of the BAT (asymmetric group). Morphological variables and angiographic and clinical outcomes were compared between the two groups. RESULTS: Of the 108 enrolled patients, 42 were in the asymmetric group. Compared with the symmetric group, the asymmetric group had significantly larger BAT diameter (mean 3.5±1.0 mm vs 4.3±1.1 mm, P=0.001) and basilar artery tip/trunk ratio (1.2±0.2 vs 1.7±0.2, P<0.001). The asymmetric group showed a significantly lower rate of complete reperfusion (71.2% vs 40.5%, P=0.002) and first pass effect (FPE) (51.5% vs 21.4%, P=0.002) than the symmetric group. The BAT asymmetry was an independent predictor of failed FPE (OR 0.299, 95% CI 0.098 to 0.918, P=0.035) and failed complete reperfusion (OR 0.275, 95% CI 0.087 to 0.873, P=0.029). CONCLUSIONS: The efficacy of MT for dBAO differs according to the anatomic morphology of the BAT. The asymmetric BAT was frequently encountered in dBAO patients and was independently associated with a reduced likelihood of complete reperfusion and FPE.

A Nationwide Web-Based Survey of Neuroradiologists' Perceptions of Artificial Intelligence Software for Neuro-Applications in Korea.

OBJECTIVE: We aimed to investigate current expectations and clinical adoption of artificial intelligence (AI) software among neuroradiologists in Korea. MATERIALS AND METHODS: In April 2022, a 30-item online survey was conducted by neuroradiologists from the Korean Society of Neuroradiology (KSNR) to assess current user experiences, perceptions, attitudes, and future expectations regarding AI for neuro-applications. Respondents with experience in AI software were further investigated in terms of the number and type of software used, period of use, clinical usefulness, and future scope. Results were compared between respondents with and without experience with AI software through multivariable logistic regression and mediation analyses. RESULTS: The survey was completed by 73 respondents, accounting for 21.9% (73/334) of the KSNR members; 72.6% (53/73) were familiar with AI and 58.9% (43/73) had used AI software, with approximately 86% (37/43) using 1-3 AI software programs and 51.2% (22/43) having up to one year of experience with AI software. Among AI software types, brain volumetry software was the most common (62.8% [27/43]). Although 52.1% (38/73) assumed that AI is currently useful in practice, 86.3% (63/73) expected it to be useful for clinical practice within 10 years. The main expected benefits were reducing the time spent on repetitive tasks (91.8% [67/73]) and improving reading accuracy and reducing errors (72.6% [53/73]). Those who experienced AI software were more familiar with AI (adjusted odds ratio, 7.1 [95% confidence interval, 1.81-27.81]; P = 0.005). More than half of the respondents with AI software experience (55.8% [24/43]) agreed that AI should be included in training curriculums, while almost all (95.3% [41/43]) believed that radiologists should coordinate to improve its performance. CONCLUSION: A majority of respondents experienced AI software and showed a proactive attitude toward adopting AI in clinical practice, suggesting that AI should be incorporated into training and active participation in AI development should be encouraged.

Association between blood pressure and endovascular treatment outcomes differs by baseline perfusion and reperfusion status.

We hypothesized that the association between BP and endovascular treatment (EVT) outcomes would differ by baseline perfusion and recanalization status. We identified 388 ICA or M1 occlusion patients who underwent EVT ≤ 24 h from onset with successful recanalization (TICI ≥ 2b). BP was measured at 5-min intervals from arrival and during the procedure. Systolic BPs (SBP) were summarized as dropmax (the maximal decrease over two consecutive measurements), incmax (the maximal increase), mean, coefficient of variation (cv), and standard deviation. Adequate baseline perfusion was defined as hypoperfusion intensity ratio (HIR) ≤ 0.5; infarct proportion as the volume ratio of final infarcts within the Tmax > 6 s region. In the adequate perfusion group, infarct proportion was closely associated with SBPdropmax (ß ± SE (P-value); 1.22 ± 0.48, (< 0.01)), SBPincmax (1.12 ± 0.33, (< 0.01)), SBPcv (0.61 ± 0.15 (< 0.01)), SBPsd (0.66 ± 0.08 (< 0.01)), and SBPmean (0.71 ± 0.37 (0.053) before recanalization. The associations remained significant only in SBPdropmax, SBPincmax, and SBPmean after recanalization. SBPincmax, SBPcv and SBPsd showed significant associations with modified Rankin Scale score at 3 months in the pre-recanalization period. In the poor perfusion group, none of the SBP indices was associated with any stroke outcomes regardless of recanalization status. BP may show differential associations with stroke outcomes by the recanalization and baseline perfusion status.