Gadolinium-enhanced intracranial aneurysm wall imaging and risk of aneurysm growth and rupture: a multicentre longitudinal cohort study.

OBJECTIVES: In patients with an unruptured intracranial aneurysm, gadolinium enhancement of the aneurysm wall is associated with growth and rupture. However, most previous studies did not have a longitudinal design and did not adjust for aneurysm size, which is the main predictor of aneurysm instability and the most important determinant of wall enhancement. We investigated whether aneurysm wall enhancement predicts aneurysm growth and rupture during follow-up and whether the predictive value was independent of aneurysm size. MATERIALS AND METHODS: In this multicentre longitudinal cohort study, individual patient data were obtained from twelve international cohorts. Inclusion criteria were as follows: 18 years or older with ≥ 1 untreated unruptured intracranial aneurysm < 15 mm; gadolinium-enhanced aneurysm wall imaging and MRA at baseline; and MRA or rupture during follow-up. Patients were included between November 2012 and November 2019. We calculated crude hazard ratios with 95%CI of aneurysm wall enhancement for growth (≥ 1 mm increase) or rupture and adjusted for aneurysm size. RESULTS: In 455 patients (mean age (SD), 60 (13) years; 323 (71%) women) with 559 aneurysms, growth or rupture occurred in 13/194 (6.7%) aneurysms with wall enhancement and in 9/365 (2.5%) aneurysms without enhancement (crude hazard ratio 3.1 [95%CI: 1.3-7.4], adjusted hazard ratio 1.4 [95%CI: 0.5-3.7]) with a median follow-up duration of 1.2 years. CONCLUSIONS: Gadolinium enhancement of the aneurysm wall predicts aneurysm growth or rupture during short-term follow-up, but not independent of aneurysm size. CLINICAL RELEVANCE STATEMENT: Gadolinium-enhanced aneurysm wall imaging is not recommended for short-term prediction of growth and rupture, since it appears to have no additional value to conventional predictors. KEY POINTS: • Although aneurysm wall enhancement is associated with aneurysm instability in cross-sectional studies, it remains unknown whether it predicts risk of aneurysm growth or rupture in longitudinal studies. • Gadolinium enhancement of the aneurysm wall predicts aneurysm growth or rupture during short-term follow-up, but not when adjusting for aneurysm size. • While gadolinium-enhanced aneurysm wall imaging is not recommended for short-term prediction of growth and rupture, it may hold potential for aneurysms smaller than 7 mm.

Headache characteristics to screen for cervicocerebral artery dissection in patients with acute onset unusual headache.

OBJECTIVES: The aim of this preplanned primary analysis was to investigate the clinical manifestations of headache to screen for CAD patients with acute onset headache only. BACKGROUND: Spontaneous cervicocerebral artery dissection (CAD) with acute onset headache is not rare in clinical practice; however, it is underdiagnosed. On the other hand, subsequent infarction or subarachnoid hemorrhage mainly occurs within 1 week of headache onset. METHODS: Between April 2017 and January 2022, we conducted a single-center, cross-sectional retrospective study on 197 consecutive referred patients from neurosurgical outpatient clinics with acute onset unusual headache (stronger or longer headache than usual). All patients underwent magnetic resonance imaging to screen for secondary headache and were diagnosed based on the diagnostic protocol. We examined patient background data and the following headache characteristics: distribution, condition at the onset of headache, accompanying vomiting or nausea, worsening headache, and analgesic effects against headache. These factors were analyzed to identify independent diagnostic predictors of CAD. In this study, the rate of missing data was 41% for improvement of headache by analgesia and multiple imputation by chained equations was performed. RESULTS: A total of 93 patients (46 men and 47 women; mean age: 48 years, range: 25-73 years) were diagnosed with CAD. Univariate logistic regression analysis showed CAD was associated with current smoking, systolic blood pressure >140 mmHg, unilateral headache, worsening headache, and no headache improvement by analgesia. Unilateral, worsening headache and no headache improvement by analgesia remained independent diagnostic predictors in multivariable logistic regression after multiple imputation. No headache improvement by analgesia had the highest sensitivity (86%), while worsening headache had the highest specificity (84%). CONCLUSIONS: CAD needs to be considered in patients with unilateral, worsening headache and no headache improvement by analgesia.

Subclavian Artery Stenting Under Cerebral Protection by Balloon-Guiding Catheter Inflation Inside the Aortic Arch at the Left Subclavian Artery Origin.

BACKGROUND: We describe a simple and novel technique for cerebral protection during left subclavian artery (SA) stenting by inflation of a balloon-guiding catheter inside the aortic arch at the SA origin. METHODS: A total of 12 patients with left SA stenosis underwent SA stenting with inflation of a balloon-guiding catheter inside the aortic arch at the left SA origin between January 2020 and December 2020. The SA stenting procedures under proximal protection were retrospectively reviewed to assess ischemic complications, hyperintense spots on diffusion-weighted imaging (DWI), and flow direction of left vertebral artery (VA) during balloon-guiding catheter inflation using ultrasonography (US). RESULTS: The success rate of the SA stenting procedure was 100% with no symptomatic ischemic complications. None of the 12 patients showed small hyperintense spots in DWI. In all patients, the left VA on US during balloon inflation showed retrograde blood flow. CONCLUSIONS: The left VA on US had retrograde blood flow during inflation of the balloon-guiding catheter inside the aortic arch at the SA origin. Therefore, the proximal balloon protection inside the aortic arch at the SA origin is a simple and maybe a safe technique for cerebral protection during SA stenting.

Association of Neutrophil Extracellular Traps with Plaque Instability in Patient with Carotid Artery Stenosis.

BACKGROUND: Vulnerable carotid plaques are related to cerebral thromboembolic and ischemic events. Neutrophil extracellular traps (NETs) can induce endothelial dysfunction and induce inflammation and coagulation. The aim of the present study was to investigate NETs in patients with carotid artery plaques. METHODS: Carotid plaques were collected by carotid endarterectomy (CEA) from 26 symptomatic and 8 asymptomatic patients between August 2017 and January 2021. The specimens were stained with hematoxylin-eosin and Elastica-van Gieson. Immunohistochemistry was performed staining by CD31 for identifying endothelial cells. NETs were detected by digoxigenin-labeled antihistone H3 (HH3) (citrulline R2+R8+R17). The relationships between the presence of NETs and patient profile and histopathological findings were assessed. RESULTS: HH3-positive cells were detected in 17 (asymptomatic = 2 symptomatic = 15) of 34 carotid plaques (median = 9.7/mm). The number of NETs was correlated with the number of diffusion-weighted imaging high-intensity lesions [P = 0.01], plaque rupture [P = 0.001], intraplaque hemorrhage [P = 0.02], intra luminal thrombus [P = 0.001], and thin fibrous cap [P = 0.001]. CONCLUSIONS: The presence of NETs was associated with the instability of carotid plaques, intraluminal thrombus, which may lead to subsequent cerebral infarction. Clarifying the roles of NETs in carotid plaques may improve the treatment of carotid artery disease.

The impact of high-resolution cone-beam CT findings on decision-making for the treatment of unruptured middle cerebral artery aneurysms.

Even with the advent of endovascular treatment for intracranial aneurysms, microsurgical clipping continues to play a significant role in the treatment of middle cerebral artery (MCA) aneurysms. Securing perforators around unruptured intracranial aneurysms (UIAs) is essential for minimizing procedural risks in each treatment option. Therefore, we herein investigated whether the findings of high-resolution cone-beam computed tomography (HR-CBCT) have an impact on decision-making for the treatment of MCA UIAs. Patients with MCA UIAs between October 2017 and September 2021 were consecutively recruited for this study. All patients underwent HR-CBCT and 3D-DSA before treatment. The imaging quality of both modalities to visualize the microvasculature around aneurysms was evaluated. Specific findings on the microvasculature surrounding aneurysms on HR-CBCT were investigated to facilitate microsurgical clipping. Fifty-two MCA UIAs were treated, including 43 by microsurgical clipping and 9 by endovascular approaches. The overall imaging quality of HR-CBCT was superior to that of 3D-DSA. Regarding microsurgical insights, sensitivity and specificity for the visualization of small vessels around aneurysms were 79 and 100%, respectively, using HR-CBCT, and 57 and 93%, respectively, using 3D-DSA. The presence of a low-density band between adhesive vessels and aneurysm sacs was indicative of successful and safe microsurgical dissection between these structures. HR-CBCT enabled visualization of the intracranial microvasculature around MCA UIAs at the submillimeter level in vivo. In cases in which the tight adhesion of the microvasculature to the aneurysm sac is indicated by HR-CBCT, an endovascular approach may be considered in order to avoid the risks associated with securing perforators.

Usefulness of stent placement for innominate artery stenosis via the right brachial artery under protection by balloon guide catheter: a technical case report.

A method of cerebral protection during endovascular treatment for innominate artery stenosis (IAS) has not been established. Herein, we report a case of symptomatic IAS in a 76-year-old woman. A balloon guide catheter (BGC) was inserted through the right brachial artery (BA) and guided distally to the stenosis. The BGC balloon was inflated, and stenting was performed with balloon protection of both the anterior and posterior cerebral circulation, without any complications. Stenting of the IAS with the BGC using the BA approach is useful, as it is a simple technique that can prevent distal embolization.

Diagnostic accuracy of MR vessel wall imaging at 2 weeks to predict morphological healing of vertebral artery dissection.

OBJECTIVES: The spontaneous healing of non-hemorrhagic intracranial vertebral artery dissection (VAD) may be associated with the stabilization of intramural hematoma (IMH). We previously suggested that the signal intensity of IMH increases until approximately 2 weeks in VAD with spontaneous healing. We herein investigated the diagnostic accuracy of the signal intensity of IMH at 2 weeks to predict the spontaneous healing of VAD. METHODS: From April 2017 to April 2021, we prospectively investigated patients with non-hemorrhagic VAD who underwent vessel wall imaging (VWI). Morphological healing of VAD was evaluated by MR angiography three months after its onset. The relative signal intensity (RSI) of IMH against the posterior cervical muscle on VWI was calculated. Univariate and multivariate analyses were performed on factors associated with the spontaneous healing of VAD among patient baseline data, vascular morphology at the diagnosis, and RSI parameters. RESULTS: Forty-eight patients (23 men and 25 women; mean age: 51 years, range: 34-73 years) with 50 non-hemorrhagic VAD were included in the present study. Spontaneous healing was observed in 28 VAD (56%). RSI two weeks after the onset of VAD (RSI2w) and morphological feature such as the string sign were associated with spontaneous healing, respectively. The multivariate logistic regression analysis identified RSI2w as an independent predictive factor of spontaneous healing (OR: 7.3; 95% CI, 1.9-28, p = 0.004). The cut-off value for RSI2w to predict spontaneous healing was 1.22 (AUC = 0.90, sensitivity: 91%, specificity: 82%). CONCLUSION: RSI2w predicted the spontaneous healing of non-hemorrhagic VAD 3 months after its onset.

Peptidylarginine Deiminase 4 as a Possible Biomarker of Plaque Instability in Carotid Artery Stenosis.

BACKGROUND AND PURPOSE: Neutrophil extracellular traps (NETs) exhibit pro-inflammatory and pro-thrombotic properties. However, they have only been reported as important regulators in atherosclerosis, especially in atherothrombosis. We investigated the presence of NETs and plaque instability in patients with carotid artery stenosis. MATERIAL AND METHODS: A total of 39 consecutive patients with carotid artery stenosis were evaluated. All patients underwent carotid artery stenting (CAS) with dual protection (simultaneous flow reversal + distal filter) and blood aspiration as a method of distal embolism prevention. Local arterial blood was aspirated at the stent site and peptidylarginine deiminase 4 (PAD4), which is essential for the formation of NETs, was measured. The relationships between PAD4 and the patient profile, blood examination and plaque data were investigated. RESULTS: The mean value of PAD4 in local arterial blood in CAS was 0.5 ng/ml. Bivariate analysis demonstrated that PAD4 was associated with the neutrophil to lymphocyte ratio (p = 0.007), high-density lipoprotein (p = 0.02), triglycerides to high-density lipoprotein ratio (p = 0.007), ulceration (p = 0.02) and plaque contrast enhancement on T1 black blood imaging (p = 0.03). In multiple linear regression analyses, PAD4 was correlated with the neutrophil to lymphocyte ratio (p = 0.01) and ulceration (p = 0.01, cut-off value: 0.49 odds ratio: 19.3). CONCLUSIONS: PAD4, representative of the presence of NETs, was high in carotid plaques with unstable features. The neutrophil to lymphocyte ratio in peripheral blood was suggested to be a biomarker of vulnerable plaques. Elucidating the role of NETs may aid in clarifying factors that promote the instability of carotid plaques.

Monitoring Intramural Hematoma on Vessel Wall Imaging to Evaluate the Healing of Intracranial Vertebral Artery Dissection.

OBJECTIVE: Unruptured intracranial vertebral artery dissection (VAD) generally heals spontaneously. A chronological evaluation of intramural hematoma (IMH) using T1-weighted vessel wall imaging (VWI) may provide a more detailed understanding of the pathophysiology of VAD. We herein investigated the relationship between chronological signal changes in IMH on VWI and the spontaneous healing of VAD. MATERIALS AND METHODS: We retrospectively investigated 26 patients with 27 unruptured VADs who underwent magnetic resonance (MR) imaging more than three times during the follow-up period. Morphological changes were evaluated using MR angiography (MRA). The relative signal intensity (RSI) of IMH against the posterior cervical muscle on T1-weighted VWI was calculated. The ratio of chronological RSI changes was defined as follows: maximum RSI/minimum RSI (RSI max/min). Based on the median value of RSI max/min, 27 VADs were divided into VADs with and without chronological RSI changes. Statistical analyses were performed to compare clinical and radiological findings between the two groups. RESULTS: Spontaneous healing occurred in 17 out of 27 VADs (63%). The median value of RSI max/min was 1.48. The RSI of VADs with chronological RSI changes (RSI max/min ≥ 1.48) increased until three weeks after their onset and decreased over time, while that of VADs without chronological RSI changes (RSI max/min < 1.48) showed no change. The frequency of healing was significantly higher in VADs with than without chronological RSI changes (100% vs 23%, p < 0.0001). CONCLUSIONS: Chronological signal changes in IMH on T1-weighted VWI have potential as a diagnostic imaging marker of the spontaneous healing of VAD.

Predictors of Reperfusion and 90-day Functional Outcome After Mechanical Thrombectomy for Large Vessel Occlusion Strokes.

OBJECTIVES: Whether elderly patients with adverse comorbidities or strong vascular meandering benefit from mechanical thrombectomy to the same degree as patients who participated in the pivotal randomized controlled trials on this procedure (MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, DAWN, and DEFUSE 3) remains unknown. We aimed to investigate the predictors of reperfusion and 90-day functional outcome using real-world clinical data, without excluding elderly patients with adverse comorbidities or patients in whom vascular access could not be achieved. MATERIALS AND METHODS: We retrospectively reviewed consecutive patients with acute ischemic stroke who underwent or in whom mechanical thrombectomy was attempted at Japanese Red Cross Matsue Hospital from April 2015 to June 2020. RESULTS: Altogether, 111 mechanical thrombectomies in 111 patients (average age 77.2 years) were attempted for acute ischemic stroke. Vascular access was not achieved in 8 (7.2%) cases. In the multivariable analysis, age ≥85 years (odd ratio [OR] 0.191, 95% confidence interval [CI] 0.057-0.641, p = 0.007) and presence of adverse comorbidities (OR 0.265, 95% CI 0.090-0.659, p = 0.016) were associated with failed reperfusion. The diffusion-weighted imaging (DWI)-ASPECT score ≥6 (OR 4.650, 95% CI 1.610-13.40, p = 0.005) was associated with good 90-day functional outcomes. Presence of adverse comorbidities was not a predictor, but it had a relatively strong correlation with poor functional outcome. CONCLUSIONS: Mechanical thrombectomy in elderly patients should be considered very carefully if they are aged ≥85 years, have low DWI-ASPECT score and have clear evidence of pre-existing adverse comorbidities.

Stenting for Innominate Artery Stenosis Under Double-Filter Protection of the Anterior and Posterior Circulation via the Right Brachial Artery.

Several protocols for angioplasty and stenting for stenosis of an innominate artery (IA) are reported, but the protocols are sometimes complicated and have disadvantages. We report a case of IA stenosis presenting ischemic symptoms in a 58-year-old woman. Stenting for the IA stenosis was performed through the right femoral artery. The cerebral protection was placed via the right brachial artery, with a filter at the right internal carotid artery and another filter at the right vertebral artery. The symptomatic IA stenosis was resolved without any complications. Regardless of the direction of blood flow, simultaneous protection of both the anterior and posterior cerebral circulation is necessary during IA stenting. Double-filter protection can provide excellent cerebral protection during an IA stenting procedure.

Pediatric pial arteriovenous fistula located at the bottom of the callosal sulcus presenting with intraventricular hemorrhage: a case report and literature review.

BACKGROUND: A pial arteriovenous fistula (pAVF) is a rare condition characterized by a direct connection between a cerebral artery and cerebral vein without an intervening nidus. The prognosis is poor in untreated cases with hemorrhagic manifestations, indicating that surgical treatment is desirable. We describe a successful endovascular treatment for a pediatric case of ruptured pAVF located at the bottom of the sulcus. CLINICAL DESCRIPTION: An 11-year-old girl presented with severe headache and mild disturbance of consciousness. Head computed tomography showed hemorrhage in the callosal sulcus and ventricle. Cerebral angiography showed an arteriovenous shunt without a nidus. The branching artery from the pericallosal artery was connected directly to the thalamostriate vein without varix, and the shunt point was located at the bottom of the callosal sulcus. The patient was diagnosed with pAVF involving a single feeder and single drainer. Emergency endovascular transarterial embolization was performed using 20% N-butyl cyanoacrylate, and the shunt disappeared completely without complications. The patient was discharged with no neurological deficits. CONCLUSION: Endovascular treatment is feasible, safe, and effective for pediatric cases of deeply located pAVF.

In-hospital mortality and poor outcome after surgical clipping and endovascular coiling for aneurysmal subarachnoid hemorrhage using nationwide databases: a systematic review and meta-analysis.

There has never been evidence for aneurysmal subarachnoid hemorrhage (aSAH) by endovascular coiling compared to surgical clipping with all grade. The present study and meta-analysis aimed to clarify the in-hospital mortality and poor outcome in the nationwide databases of patients with all grade aSAH between them. The outcome of modified Rankin scale (mRS) at discharge was investigated according to the comprehensive nationwide database in Japan. The propensity score-matched analysis was conducted among patients with aSAH in this database registered between 2010 and 2015. Meta-analysis of studies was conducted based on the nationwide databases published from 2007 to 2018. According to this propensity score-matched analysis, no significant association for poor outcome of mRS > 2 was shown between surgical clipping and endovascular coiling (47.7% vs 48.3%, p = 0.48). However, significantly lower in-hospital mortality was revealed after surgical clipping than endovascular coiling (7.1% vs 12.2%, p < 0.001). Meta-analysis of propensity score-matched analysis in the nationwide database showed no significant association for poor outcome at discharge between them (odds ratio [OR], 1.08; 95% confidence interval [CI], 0.93 to 1.26; p = 0.31). Meta-analysis of propensity score-matched analysis for in-hospital mortality was lower after surgical clipping than after endovascular coiling, however, without significant difference (OR, 0.74; 95% CI, 0.52 to 1.04; p = 0.08). Further prospective randomized controlled study with all grade aSAH should be necessary to validate the in-hospital mortality and poor outcome.

Early venous filling after reperfusion therapy in acute ischemic stroke.

BACKGROUND AND PURPOSE: Early venous filling after endovascular mechanical thrombectomy in acute ischemic stroke (AIS) is a specific finding that may serve as a biomarker for intracranial hemorrhage. However, the pathophysiology of early venous filling and postoperative hemorrhage remains unclear. The aim of this study was to investigate correlation between early venous filling and various factors involving patient demographics and perioperative imaging. METHODS: We prospectively analyzed 35 patients with AIS due to cardioembolism (CE) who underwent successful acute revascularization (TICI ≥2). Ischemic lesions were scored by magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI). Outcomes were assessed using the modified Rankin Scale (mRS) 90 days after stroke onset. Blood flow analysis was evaluated by MRI with arterial spin labeling (ASL). Early venous filling was assessed by digital subtraction angiography (DSA). Univariate analysis was performed to investigate correlations between early venous filling and patient demographics and imaging findings. RESULTS: Early venous filling was observed in 22 of 35 (66%) patients after reperfusion therapy. There was a significant correlation between early venous filling and DWI-ASPECTS (6.2 vs 8.8, p=0.0003), outcome (5 vs 9, p=0.006), hyperperfusion (17 vs 1, p< 0.0001), and hemorrhagic transformation (17 vs 1, p=0.005). CONCLUSIONS: This comprehensive study revealed that early venous filling after reperfusion therapy is associated with postoperative hyperperfusion. Early venous filling may be a marker of the process of hyperperfusion, leading to hemorrhage and an unfavorable outcome. Detection of early venous filling may be an important finding on DSA for subsequent intensive perioperative management.

Blood Flow Pattern Analysis for Carotid Plaque Evaluation.

BACKGROUND AND PURPOSE: Previous studies suggested that turbulent flow is closely related to plaque vulnerability. Two-dimensional (2D) flow analysis is a novel modality that enables real-time blood flow analysis by picturing particle movement in the contrast medium. We evaluated flow patterns in the carotid plaque to investigate the correlation between blood flow and plaque vulnerability. MATERIAL AND METHODS: A total of 36 consecutive patients with cervical carotid artery stenosis were evaluated. The flow pattern of carotid artery stenosis was evaluated using 2D real-time flow analysis in the digital subtraction angiography (DSA). The flow pattern was classified into either turbulent or laminar flow as vectors. Plaque vulnerability was evaluated on MR plaque imaging. Univariate analysis was performed to assess the correlation between the flow pattern and plaque features. RESULTS: The turbulent pattern was identified in 28 of 36 plaques (77.8%). Turbulence around plaques was significantly associated with Gadolinium enhancement (P = .0004). The maximum degree of stenosis (P = .0005) and concomitant ulceration (P = .02) were significantly associated with the turbulent pattern. There was no relationship between the turbulent pattern and clinical neurological symptoms. CONCLUSIONS: In the present study, the majority of carotid plaques exhibited a turbulent flow pattern, which was significantly associated with Gadolinium enhancement on MR plaque imaging and morphologic factors. Thus, real-time flow analysis may clarify the pathophysiology of plaque instability and the formation of ulceration.

Magnetic resonance vessel wall imaging predicts morphological deterioration in unruptured intracranial artery dissection.

OBJECTIVE: The mechanism involved in progression of unruptured intracranial artery dissection (IAD) is poorly understood. We investigated the relationship between contrast enhancement of dissecting lesions on magnetic resonance vessel wall imaging (MR-VWI) and unruptured IAD progression on the hypothesis that this finding might predict its instability. METHODS: A total of 49 unruptured IADs were investigated retrospectively. Three-dimensional T1-weighted fast spin-echo sequences were obtained before and after injection of contrast medium, and the dissecting lesion/pituitary stalk contrast enhancement ratio (CRstalk) was calculated. Unruptured IAD progression was defined as morphological deterioration; progressive dilatation or stenosis. The relations between unruptured IAD progression and potential risk factors were statistically investigated. RESULTS: Morphological deterioration was demonstrated in eleven of 49 unruptured IADs (22 %). The CRstalk value and male predominance was significantly higher in progressed IADs than stable ones (1.0 vs. 0.65; p = 0.0035, 82% vs 37%; p= 0.015, respectively). On stepwise multivariable logistic regression analysis, the CRstalk value was independently associated with unruptured IAD progression with odds ratio of 102.5 (95% CI, 2.59-4059, P=0.0013). The optimal cutoff value of CRstalk to estimate IADs with progression was 0.87 (sensitivity, 0.82; specificity, 0.74). Multimodalic images showed contrast enhancement on VWI corresponded to residual stagnant flow in dissecting lesions. CONCLUSIONS: Quantitative analysis of contrast enhancement on VWI could predict instability of unruptured IADs. Contrast enhancement in dissecting lesions would be a clue to understand the mechanism of unruptured IAD progression.

Vessel Wall Imaging of Evolving Unruptured Intracranial Aneurysms.

Background and Purpose- Unruptured intracranial aneurysms (UIAs) have various scenarios of growth and rupture. Magnetic resonance vessel wall imaging can detect aneurysmal wall thickening with inflammation and neovascularization. This study was performed to explore the vessel wall imaging findings of UIAs with consecutive follow-up. Methods- A total of 60 aneurysms with serial angiography over 2 years (mean period, 49 months, range, 24-192 months) were evaluated by vessel wall imaging. UIAs were morphologically categorized into 3 patterns: stable, whole sac expansion, or daughter sac formation. Aneurysm wall enhancement (AWE) was evaluated after administration of gadolinium. Results- Thirty-three of the 60 UIAs (55%) demonstrated no morphological changes, whereas 16 UIAS (27%) showed whole sac expansion and 11 UIAs (18%) demonstrated daughter sac formation. AWE was significantly less frequent in stable UIAs compared with UIAs showing morphological changes ( P<0.01). Aneurysms with daughter sac formation showed a significantly higher frequency of AWE than those demonstrating whole sac expansion. In the majority of UIAs with daughter sac formation, AWE was detected in the main aneurysm and not in the developing component. Conclusions- UIAs demonstrate various modes of growth. The pattern of AWE might be useful for identifying unfavorable morphological changes of UIAs.

Neointimal formation after carotid artery stenting: phantom and clinical evaluation of model-based iterative reconstruction (MBIR).

OBJECTIVES: The objective of this study was to investigate the usefulness of model-based iterative reconstruction (IR) for detecting neointimal formations after carotid artery stenting. METHODS: In a cervical phantom harbouring carotid artery stents, we placed simulated neointimal formations measuring 0.40, 0.60, 0.80 and 1.00 mm along the stent wall. The thickness of in-stent neointimal formations was measured on images reconstructed with filtered-back projection (FBP), hybrid IR (AIDR 3D), and model-based IR (FIRST). The clinical study included 43 patients with carotid stents. Cervical computed tomography (CT) images obtained on a 320-slice scanner were reconstructed with AIDR 3D and FIRST. Five blinded observers visually graded the likelihood of neointimal formations on AIDR 3D and AIDR 3D plus FIRST images. Carotid ultrasound images were the reference standard. We analysed results of visual grading by using a Jack-knife type receiver observer characteristics analysis software. RESULTS: In the phantom study, the difference between the measured and the true diameter of the neointimal formations was smaller on FIRST than FBP or AIDR 3D images. In the clinical study, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of AIDR 3D were 58%, 88%, 83%, 67% and 73%, respectively. For AIDR 3D plus FIRST images they were 84%, 78%, 80%, 82% and 81%, respectively. The mean area under the curve was significantly higher on AIDR 3D plus FIRST than AIDR 3D images (0.82 vs 0.72; p < 0.01). CONCLUSIONS: The model-based IR algorithm helped to improve diagnostic performance for the detection of neointimal formations after carotid artery stenting. KEY POINTS: • Neointimal formations can be visualised more accurately with model-based IR. • Model-based IR improves the detection of neointimal formations after carotid artery stenting. • Model-based IR is suitable for follow up after carotid artery stenting.

Hyperperfusion after Endovascular Reperfusion Therapy for Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Patients with acute ischemic stroke (AIS) may display prolonged neurological deficits and conscious disturbance even after successful endovascular thrombectomy. We hypothesized that hemodynamic change after reperfusion might influence outcomes. This study investigated the factors causing hyperperfusion and outcomes. METHODS: We retrospectively analyzed 27 patients with AIS who underwent successful acute revascularization (TICI: Thrombolysis in Cerebral Infarction 2b + 3). Changes of the neurological status were precisely assessed by using the National Institutes of Health Stroke Scale (NIHSS). Ischemic lesions were scored by MRI with diffusion-weighted imaging (DWI), and blood flow in the middle cerebral artery territory was assessed by MRI with arterial spin labeling. Univariate analysis was performed to investigate correlations between hyperperfusion and demographic factors or the functional prognosis. RESULTS: Thirteen of the 27 (48%) patients developed hyperperfusion after reperfusion. A significant correlation was seen between hyperperfusion and the improvement of NIHSS at 24 hours (P < .0001), the duration of disturbance of consciousness (days) (P < .0001), DWI-ASPECTS (P = .001), hemorrhagic transformation (P = .007), and mRS less than or equal to 2 at 90 days (P = .007). CONCLUSIONS: The present findings suggested that some patients with AIS will develop hyperperfusion after successful acute revascularization. The status of hyperperfusion could prolong conscious disturbance and affect outcomes. Since the mechanism of hyperperfusion after revascularization depends on stroke etiology, diagnosing the type of ischemic stroke in the acute stage is important for managing postoperative treatment.

Decreased Antiatherogenic Protein Levels are Associated with Aneurysm Structure Alterations in MR Vessel Wall Imaging.

OBJECTIVE: Thickened intracranial aneurysm wall with atherosclerotic remodeling is a part of its degenerative scenario. Current magnetic resonance (MR)-vessel wall imaging enables the detection of atherosclerotic wall thickening as aneurysm wall enhancement. The purpose of this study was to examine the correlation between identified atherosclerotic remodeling in vessel wall imaging, and systemic atherosclerosis-related risk factors. METHODS: A total of 39 aneurysms in 38 consecutive patients scheduled to undergo microsurgical clipping or endovascular coiling of intracranial aneurysms were prospectively evaluated. All patients underwent aneurysm MR-vessel wall imaging and the presence of aneurysm wall enhancement on contrast-enhanced vessel wall imaging was evaluated. The relationship between aneurysm wall enhancement and patient demographic data, aneurysm morphology and atherosclerosis-related risk factors including blood laboratory data were assessed. RESULTS: Aneurysm wall enhancement was detected in 19 of 39 intracranial aneurysms (48.7%). The maximum diameter of the intracranial aneurysm (P < .01), apolipoprotein A2 (P < .01) and apolipoprotein C2 (P = .01) was significantly associated with the presence of aneurysm wall enhancement. In multivariate logistic regression analyses, the maximum diameter of the intracranial aneurysm (odds ratio: 1.67, 95% confidence interval: 1.17-3.05) and decreased apolipoprotein A2 (odds ratio: 0.62, 95% confidence interval: 0.34-0.97) was significantly correlated with aneurysm wall enhancement. CONCLUSIONS: Rather than atherosclerotic factors, antiatherogenic proteins reduction was associated with aneurysm wall enhancement in vessel wall imaging. To elucidate antiatherogenic factors might to help find out promoting factor of unruptured intracranial aneurysms instability.