Declining trend in the estimated annual rupture rate of unruptured cerebral aneurysms in Japan: a nationwide study.

The incidence of subarachnoid hemorrhages (SAHs) in Japan has recently decreased. However, trends in the annual rates of unruptured cerebral aneurysms (UCAs) are unclear because calculations based on follow-up periods are limited to patients with ruptured cerebral aneurysms. We aimed to clarify current trends in the estimated annual rupture rates of UCAs in Japan and to identify the most relevant contributing factors. We analyzed data from the Japanese Ministry of Health, Labour and Welfare and records of the Japan Neurosurgical Society. The estimated annual rupture rates of UCAs between 2003 and 2018 were calculated according to age-adjusted mortality rates of SAH and number of treated ruptured cerebral aneurysms (RCAs). We estimated trends in annual rupture rates using sensitivity analysis and assessed associations between estimated annual rupture rates and the prevalences of hypertension and current smoking. The estimated annual rupture rate of UCAs significantly decreased from 1.44 to 0.87% and from 0.92 to 0.76%, respectively, in terms of age-adjusted mortality rates of SAH and number of treated RCAs (p < 0.001). The range of changes in estimated annual rupture rates of UCAs was - 1.13%‒0.83%, representing a declining UCA trend of 88%. The estimated annual rupture rates of UCAs declined by 0.02-0.10% and 0.01-0.05% with every percent decrease in hypertension and current smoking prevalence, respectively. The estimated annual rupture rate of UCAs has recently decreased in Japan, possibly due to a decrease in the prevalence of hypertension rather than smoking.

Compatibility of the semijailing technique with extremely soft i-ED coils for ruptured blood blister-like and dissecting aneurysms: patient series.

BACKGROUND: Optimal treatment options for ruptured blood blister-like aneurysms (BBAs) and dissecting aneurysms (DAs) have not yet been established. Endovascular treatment may achieve vessel reconstruction with the preservation of antegrade blood flow; however, securing curative hemostasis at the fragile rupture point remains a major concern. OBSERVATIONS: Two ruptured BBAs and two ruptured DAs treated by stent-assisted coiling with the semijailing technique in the last 2 years are described herein. The devices used were braided stents and i-ED coils, which are new low-memory shape and extremely soft coils. Neither rebleeding nor ischemic complications were observed. All patients had a favorable outcome and showed no recurrence after treatment. LESSONS: All aneurysms were treated without ischemic complications or rebleeding. The good compatibility of braided stents and the new concept coils in stent-assisted coiling by the semijailing technique provides insight into these intractable hemorrhagic vascular pathologies.

Usefulness of combined bypass surgery for moyamoya disease in infants under 1 year of age: A technical case report.

Background: Among pediatric cases of moyamoya disease (MMD), cerebral ischemic symptoms often progress and worsen rapidly in infants under one year of age; therefore, it is important to treat them as early as possible. However, direct bypass surgery is often technically difficult for infants due to their small blood vessels. Here, we describe our technique to resolve the technical challenges encountered during superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass surgery in infants aged <1 year with MMD, focusing on specific procedures. Case Description: We performed bilateral STA-MCA and indirect bypass in a 1-year-old girl with MMD and cerebral infarction. Before treatment, a peripherally inserted central venous catheter (PICC) was placed to avoid ischemic attacks associated with crying, dehydration, and malnutrition. All examinations and procedures that would be stressful to the patient, such as blood examinations, were performed using PICC or under sedation. The STA-MCA diameters were 0.8 and 1.2 mm, respectively. After suturing the planned anastomosis with one stitch using an 11-0 monofilament nylon thread, the thread was lifted upward, and the arterial wall was incised. Anastomosis was performed using an 11-0 monofilament nylon thread with 2-4 stitches on each side. The operation was completed without patency problems. Postoperative blood flow improved, and the patient had a good treatment course. Conclusion: Direct bypass for MMD patients aged <1 year is technically challenging; however, the vessels can be connected if the procedure is carefully performed with consideration of the characteristics of the infant's vessels.

Pulsatility index of superficial temporal artery was associated with cerebral infarction after direct bypass surgery for moyamoya disease.

OBJECTIVE: Direct bypass surgery by superficial temporal artery (STA) - middle cerebral artery anastomosis is an established procedure for moyamoya disease (MMD). However, some patients may develop cerebral infarction (CI) due to the watershed shift phenomenon after the surgery. This study sought to investigate the correlation between the postoperative changes of STA flow as well as cerebral blood flow (CBF) and the incidence of CI after direct bypass surgery for MMD. METHODS: We conducted a retrospective study of 62 hemispheres in 50 subjects who underwent direct bypass surgery for MMD. All subjects underwent pre- and post-operative MR imaging, ultrasound evaluation of STA, and single-photon emission computed tomography. The presence of CI was correlated with preoperative CBF, the delta difference of each value of the STA between before and after the surgery, and the postoperative increase ratio of CBF. RESULTS: All bypass procedures were patent, and CI was observed in 4 cases (6.4%). There was no significant association between the incidence of CI and both pre- and post-operative CBF. However, there was a significant difference in delta pulsatility index (PI) of the STA between cases with or without CI (-0.38±0.22 and -0.87±0.63, respectively, p=0.03). Whereas, other factors did not show any significant differences between those with or without CI. CONCLUSIONS: A relatively high postoperative PI of the STA was significantly associated with the incidence of CI after direct bypass surgery for MMD. A larger study is needed to confirm these findings.

Effectiveness of tuning an artificial intelligence algorithm for cerebral aneurysm diagnosis: a study of 10,000 consecutive cases.

Diagnostic image analysis for unruptured cerebral aneurysms using artificial intelligence has a very high sensitivity. However, further improvement is needed because of a relatively high number of false positives. This study aimed to confirm the clinical utility of tuning an artificial intelligence algorithm for cerebral aneurysm diagnosis. We extracted 10,000 magnetic resonance imaging scans of participants who underwent brain screening using the "Brain Dock" system. The sensitivity and false positives/case for aneurysm detection were compared before and after tuning the algorithm. The initial diagnosis included only cases for which feedback to the algorithm was provided. In the primary analysis, the sensitivity of aneurysm diagnosis decreased from 96.5 to 90% and the false positives/case improved from 2.06 to 0.99 after tuning the algorithm (P < 0.001). In the secondary analysis, the sensitivity of aneurysm diagnosis decreased from 98.8 to 94.6% and the false positives/case improved from 1.99 to 1.03 after tuning the algorithm (P < 0.001). The false positives/case reduced without a significant decrease in sensitivity. Using large clinical datasets, we demonstrated that by tuning the algorithm, we could significantly reduce false positives with a minimal decline in sensitivity.

Flow Redirection Endoluminal Device Flow Diverter Placement for Recurrent Dolichoectatic Vertebrobasilar Artery Aneurysm Treated with Multiple Low-Profile Visualized Intraluminal Support Stents: A Case Study.

Objective: We report a case of dolichoectatic vertebrobasilar aneurysms treated with multiple low-profile visualized intraluminal support (LVIS) stents followed by flow redirection endoluminal device (FRED) flow diverter to prevent the growth of the thrombosed aneurysm. Case Presentation: A 71-year-old man developed diplopia due to oculomotor nerve palsy after 11 years of follow-up for an enlarging thrombosed dolichoectatic vertebrobasilar artery aneurysm. He initially had a fusiform thrombosed aneurysm from the right vertebral artery to the basilar artery. This lesion was tortuous and strongly compressed the pons. A total of 11 LVISs were deployed from the right posterior cerebral artery to the right vertebral artery. Six months after surgery, there was no enlargement of the thrombosed aneurysm on MRI and the contrast leakage out of the stent was markedly reduced in DSA compared to immediately after surgery. One year and seven months after surgery, contrast leakage out of the stent was increased in DSA. The FRED was placed within the overlapped LVISs, and contrast leakage was somewhat reduced. After 2 years and 7 months from the initial treatment, the contrast leakage was still observed. However, there was no enlargement of the aneurysm and no complications related to treatments were observed. Conclusion: Treatment with multiple LVIS stents followed by FRED flow diverter treatment for dolichoectatic vertebrobasilar aneurysms (DVAs) may be one of the treatment options for controlling the growth of thrombotic aneurysms without complications, but the long-term prognosis of this case is unclear, and careful follow-up is mandatory.

Impact of intravenously administered cranial bone-derived mesenchymal stem cells on functional recovery in experimental spinal cord injury.

Impairments of the central nervous system, such as stroke, brain trauma, and spinal cord injury (SCI), cannot be reversed using current treatment options. Herein, we compared the characteristics of rat cranial bone-derived mesenchymal stem cells (rcMSCs) and rat bone marrow-derived mesenchymal stem cells (rbMSCs). We also investigated the therapeutic effects of intravenously administered rcMSCs and rbMSCs in a rat model of cervical SCI (cSCI) and elucidated its undrelying mechanism. Comprehensive comparative bioinformatics analysis of rcMSCs and rbMSCs RNA sequencing revealed that genes associated with leukocyte transendothelial migration and chemokine signaling were significantly downregulated in rcMSCs. Rats were divided into three groups that received intrtravenous administration of rcMSC, rbMSC, or phosphate-buffered saline (control) 24 h after cSCI. The rcMSC-treated group showed improved functional recovery over the rbMSC-treated and control groups, and reduced lesion volume compared with the control group. The mRNA expression of nitric oxide synthase 2 at the spinal cord lesion site was significantly higher in the rcMSC-treated group than in the control and rbMSCs-treated groups, whereas that of transforming growth factor-ß was significantly higher in the rcMSC-treated group compared to that in the control group. The transcriptome data indicated that rcMSCs and rbMSCs differentially affect inflammation. The intravenous administration of rcMSCs contributed to functional recovery and lesion reduction in cSCI. The rcMSCs have the potential to induce an anti-inflammatory environment in cSCI.

A novel rat model for longitudinal electrophysiological evaluation after cold-induced brain injury.

OBJECTIVE: Cerebral contusion models of cold-induced injury are widely used in animal studies. However, owing to the difficulty of longitudinal recording of electrical stimulation transcranial motor evoked potential (tcMEP) in brain injury models of incomplete paralysis, to the authors' knowledge there have been no multimodal evaluations of cold-induced brain injury models that have included motor function and electrophysiological and histological evaluations. Therefore, in this study the authors aimed to perform a multimodal evaluation of a rat model of brain injury. METHODS: A brain injury model in female rats and a tcMEP recording technique based on the authors' previous study were established to enable multifaceted analysis, including longitudinal electrophysiological evaluation. RESULTS: The model showed incomplete paralysis of the right forelimb. Motor function showed recovery over time, and histological evaluation showed tissue changes associated with cerebral contusion. In addition, stable tcMEP waveforms were recorded before and after surgery and up to 4 weeks after injury. The tcMEP amplitude decreased significantly after injury and recovered over time. Furthermore, the amplitudes at 1, 7, and 14 days after injury were significantly lower than those at preinjury (p < 0.0006, p < 0.0007, and p < 0.0067, respectively). CONCLUSIONS: In the present study, the authors established a novel cold-induced brain injury rat model and technique that allowed for the evaluation of longitudinal tcMEP recording and demonstrated that multimodal evaluation for brain injury can be performed. This model can potentially be applied in future investigations of various therapies for brain injury.

The 5-Factor Modified Frailty Index as a More Useful Associated Factor Than Chronological Age After Unruptured Cerebral Aneurysm Surgery: A Nationwide Registry Study.

BACKGROUND: Although chronological age is associated with mortality and morbidity after surgery for unruptured cerebral aneurysms (UCAs), there is little evidence regarding an association between the simplified 5-factor modified frailty index (mFI-5) and postoperative outcomes based on age group. OBJECTIVE: To investigate the association of the mFI-5 score with worse outcomes, mortality, and complications in patients after surgery for UCA by chronological age groups using a Japanese national database. METHODS: This study included 32 902 patients with UCAs enrolled in a Japanese national database between 2011 and 2015. Age group (younger than 65 years, 65-74 years, and 75 years or older), sex, UCA location, treatment, medications, Barthel Index (BI), medical history, mFI-5 score, and in-hospital mortality and complications were evaluated. We identified risk factors for worsening BI score, in-hospital mortality, and overall postoperative complications in each age group. RESULTS: In total, 14 465 patients were enrolled in this study. Multivariable analysis showed that elderly groups and patients with an mFI-5 score ≥2 items were associated with worsening BI scores (odds ratio 1.95; 95% CI 1.52-2.51) and in-hospital complications (odds ratio 1.79; CI 1.49-2.15), despite having no association with in-hospital mortality. Multivariable analysis by age groups showed that the mFI-5 score ≥2 items was associated with in-hospital complications in all age groups, unlike chronological age in patients younger than 74 years. CONCLUSION: The mFI-5 score was a more useful associated factor of in-hospital complications than chronological age in patients younger than 74 years undergoing surgery for UCA.

Establishment of longitudinal transcranial stimulation motor evoked potentials monitoring of the forelimbs and hindlimbs in an ischemic stroke rat model.

Evaluation of motor function ischemic stroke rat models includes qualitative assessments such as the modified neurological severity score (mNSS). However, mNSS cannot evaluate the function of forelimbs and hindlimbs separately. We quantitatively assessed motor function in a middle cerebral artery occlusion (MCAO) rat model of ischemic stroke. We recorded transcranial stimulation motor evoked potentials (tcMEPs) from MCAO rats and measured the changes in onset latency and amplitude at the forelimbs and hindlimbs up to 28 days after stroke. All MCAO subjects showed hemiparesis. The amplitudes of tcMEPs in both fore- and hindlimbs were inversely correlated with mNSS scores, but the amplitudes in the forelimbs improved later than those in the hindlimbs. The onset latency of tcMEPs in the forelimbs and hindlimbs remained almost unchanged during the follow-up period. Our results showed the differences in tcMEPs amplitude recovery times between the forelimbs and hindlimbs after MCAO, which emphasizes the importance of separately evaluating forelimbs and hindlimbs in post-ischemic stroke models. This minimally invasive and longitudinal quantitative method could be useful for further research on diseases and neurogenesis.

Natural history of acute unruptured vertebral basilar artery dissection: Temporal changes in imaging findings and contributory factors.

OBJECTIVES: To investigate temporal changes in imaging findings of conservatively treated acute unruptured vertebral basilar artery dissection (VBAD) and its contributing factors. METHODS: Fifty-three patients who underwent conservative treatment for 64 cases of acute VBAD diagnosed between January 2006 and March 2019 with follow-up of at least 12 months after onset were retrospectively investigated. Statistical analyses of age, sex, medical history, pattern of onset, lesion site, imaging findings and changes over time, regular medication, and outcomes were performed. RESULTS: Changes in the vascular morphology of the lesion site during the follow-up period were observed in only 23 (43 %) patients (median time until change: 19 days). Univariate analysis of factors contributing to morphological changes at the dissection site showed that changes were significantly more likely in younger patients (p = 0.011). Patients taking antiplatelet drugs had a significantly greater rate of deterioration at the dissection site (p = 0.028) than others. On multivariate analysis, age was an independent factor contributing to changes at the dissection site, and taking antiplatelet drugs, particularly clopidogrel, was an independent factor contributing to deterioration. No patient developed intracranial hemorrhage, cerebral infarction, or worsening of neurological symptoms during follow-up. CONCLUSIONS: Morphological changes at the dissection site are more likely in younger patients with acute unruptured VBAD and those taking antiplatelet drugs. However, chances of intracranial hemorrhage, cerebral infarction, or worsening of neurological symptoms during conservative therapy are low; therefore, acute unruptured VBAD may be considered a benign condition.

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.

Longitudinal electrophysiological changes after mesenchymal stem cell transplantation in a spinal cord injury rat model.

Transcranial electrically stimulated motor-evoked potentials (tcMEPs) are widely used to evaluate motor function in humans and animals. However, the relationship between tcMEPs and the recovery of paralysis remains unclear. We previously reported that transplantation of mesenchymal stem cells to a spinal cord injury (SCI) rat model resulted in various degrees of recovery from paraplegia. As a continuation of this work, in the present study, we aimed to establish the longitudinal electrophysiological changes in this SCI rat model after mesenchymal stem cell transplantation. SCI rats were established using the weight-drop method. The model rats were transvenously transplanted with two types of mesenchymal stem cells (MSCs), one derived from rat cranial bones and the other from the bone marrow of the femur and tibia bone, 24 h after SCI. A phosphate-buffered saline (PBS) group that received only PBS was also created for comparison. The degree of paralysis was evaluated over 28 days using the Basso-Beattie-Bresnahan (BBB) scale and inclined plane task score. Extended tcMEPs were recorded using a previously reported bone-thinning technique, and the longitudinal electrophysiological changes in tcMEPs were investigated. In addition, the relationship between the time course of recovery from paralysis and reappearance of tcMEPs was revealed. The appearance of the tcMEP waveform was earlier in MSC-transplanted rats than in PBS-administered rats (earliest date was 7 days after SCI). The MEP waveforms also appeared at approximately the same level on the BBB scale (average score, 11 points). Ultimately, this study can help enhance our understanding of the relationship between neural regeneration and tcMEP recording. Further application of tcMEP in regenerative medicine research is expected.

Abdominal Aortic Calcification Volume Is Associated with Wall Enhancement of Unruptured Intracranial Aneurysm.

OBJECTIVE: Inflammatory atherosclerotic remodeling of unruptured intracranial aneurysms (UIAs) wall, which could be detected as aneurysm wall enhancement (AWE) in MR vessel wall imaging (VWI), plays a pivotal role in pathophysiology of progression to rupture. On the other hand, abdominal aortic calcification reflects the extent of systemic atherosclerosis, which in turn predicts the risk of atherosclerotic cardiovascular as well as cerebrovascular diseases. This study sought to investigate whether the abdominal aortic calcification was associated with increased wall enhancement of UIAs in VWI. METHODS: This retrospective study reviewed subjects who underwent evaluation using 3T MR-VWI of UIAs and abdominal CT before endovascular treatments for UIAs between 2018 to 2020. Abdominal aortic calcification volume (ACV) was quantitatively measured from abdominal CT scans between renal arteries and bifurcation. The presence of AWE was correlated with patient profile, aneurysm morphology, and the ACV. RESULTS: A total of 42 patients with 50 UIAs were included. AWE was detected in 19 (38.0%) UIAs. Maximum diameter (9.2 ± 5.0 mm vs 5.3 ± 1.5 mm, P < 0.01) and the ACV (8.2 ± 6.0 mL vs 4.7 ± 4.6 mL, P = 0.038) were significantly higher in UIAs with AWE than those without AWE. CONCLUSIONS: The ACV was significantly associated with increased wall enhancement of UIAs. Systemic atherosclerosis might be a risk factor for the instability of UIAs. Future studies examining the effect of medications for systemic atherosclerosis on the extent of AWE in UIAs is warranted.

Changes in Short-Term Outcomes After Discharge in Patients with Aneurysmal Subarachnoid Hemorrhage: A Multicenter, Prospective, Observational Study.

OBJECTIVE: The objective of the study was to clarify the prevalence of and factors associated with changes in patients' outcomes between discharge and 3 months after the onset of aneurysmal subarachnoid hemorrhage (aSAH). Additionally, the World Federation of Neurosurgical Societies (WFNS) and modified WFNS (mWFNS) scales were compared. METHODS: The data of curatively treated patients with aSAH, collected prospectively in the mWFNS scale study between January 2010 and December 2012, were analyzed retrospectively. The improvement or decline in the modified Rankin Scale (mRS) scores between discharge and 3 months after onset was determined. A multivariable logistic regression analysis was performed to identify factors, such as age and WFNS and mWFNS grades, associated with changes in the outcome. RESULTS: The mRS scores improved in 28.3% and declined in 2.5% of the patients. WFNS and mWFNS grades Ⅱ-V on admission were significantly associated with improved mRS scores at 3 months after onset. Older age (age: 65-74 years vs. age <65 years, odds ratio: 6.59, 95% confidence interval: 1.28-34.01; age ≥75 years vs. age <65 years, odds ratio: 17.67, 95% confidence interval: 2.11-148.26) and WFNS grade III were significantly associated with a decline in mRS scores at 3 months after onset. CONCLUSIONS: The optimal timing for postdischarge assessment of outcomes may be at 3 months after onset, especially in older patients with aSAH. The mWFNS scale is presumed to more accurately assess the outcomes of patients with aSAH than the WFNS scale, as demonstrated in this study.

Factors contributing to restenosis after carotid artery stenting and the usefulness of magnetic resonance plaque imaging: A study of 308 consecutive patients.

PURPOSE: Carotid artery stenting (CAS) is an alternative treatment strategy to carotid endarterectomy. However, post-intervention in-stent restenosis (ISR) remains a complication. The timing, frequency, and prognostic factors of ISR are unclear. The incidence and timing of post-CAS ISR were investigated, including plaque imaging to investigate the prognostic factors. METHODS: We retrospectively investigated 308 patients diagnosed with carotid stenosis who underwent CAS between April 2008 and April 2020. The patients also underwent carotid ultrasonography (US) at 1, 3, 6, and 12 months postinterventionally and every 6 months thereafter. Contributory factors in patients with ISR were also investigated. RESULTS: The percentage value of ISR was 4.9% (15/308). The median time from the procedure to ISR was 7 months. The ISR rate was higher for patients with a plaque/muscle ratio of ≤ 2.30 on T2-weighted imaging (T2WI) on black-blood magnetic resonance imaging (BB MRI) (p = 0.022). A plaque/muscle ratio of ≤ 2.30 on BB MRI T2WI was identified as an independent risk factor for ISR. A comparison of the incidence of ISR and the plaque/muscle ratio level on MRI T2WI was also significant (p < 0.001). In T2WI imaging of BB MRI, the cutoff value for detecting ISR from the Plaque/Muscle ratio was 1.310 [area under the curve (AUC) = 0.935, Sensitivity = 100%, specificity = 85.2%]. CONCLUSIONS: The incidence of post-CAS ISR was 4.9%, at a median time of 7 months after stenting. Plaque/muscle ratio on T2WI in pre-intervention MRI plaque imaging may be a useful predictor of post-intervention ISR.

Transplantation of rat cranial bone-derived mesenchymal stem cells promotes functional recovery in rats with spinal cord injury.

Cell-based therapy using mesenchymal stem cells (MSCs) is a novel treatment strategy for spinal cord injury (SCI). MSCs can be isolated from various tissues, and their characteristics vary based on the source. However, reports demonstrating the effect of transplanted rat cranial bone-derived MSCs (rcMSCs) on rat SCI models are lacking. In this study, we determined the effect of transplanting rcMSCs in rat SCI models. MSCs were established from collected bone marrow and cranial bones. SCI rats were established using the weight-drop method and transplanted intravenously with MSCs at 24 h post SCI. The recovery of motor function and hindlimb electrophysiology was evaluated 4 weeks post transplantation. Electrophysiological recovery was evaluated by recording the transcranial electrical stimulation motor-evoked potentials. Tissue repair after SCI was assessed by calculating the cavity ratio. The expression of genes involved in the inflammatory response and cell death in the spinal cord tissue was assessed by real-time polymerase chain reaction. The transplantation of rcMSCs improved motor function and electrophysiology recovery, and reduced cavity ratio. The expression of proinflammatory cytokines was suppressed in the spinal cord tissues of the rats that received rcMSCs. These results demonstrate the efficacy of rcMSCs as cell-based therapy for SCI.

Transient Cerebral Vasospasm After Carotid Artery Stenting: A Case Report and Literature Review.

BACKGROUND: Cerebral embolism after carotid artery stenting (CAS) is a well-known complication, but cerebral ischemia owing to cerebral vasospasm after CAS is rare and has seldom been reported. We describe a patient with transient ischemic complications owing to reversible cerebral vasospasm of the middle cerebral artery after CAS. CASE DESCRIPTION: A 74-year-old man presented with right hemiparesis caused by acutely scattered brain infarction in the left cerebral hemisphere. Magnetic resonance angiography showed severe stenosis of the left cervical internal carotid artery origin. CAS under a distal filter protection was performed without any intraprocedural complications, but 12 hours later, the patient had aphasia and Gerstmann syndrome. Urgent magnetic resonance imaging revealed no evidence of an intracranial hemorrhage or new cerebral infarction. However, magnetic resonance angiography showed diffuse vasospasm of the left middle cerebral artery. His symptoms and imaging findings improved gradually with conservative treatment. The patient was discharged without new neurologic deficit or recurrent attack 3 weeks after CAS. CONCLUSIONS: In a patient with delayed neurologic symptoms after CAS, the possibility of cerebral vasospasm should be kept in mind to select appropriate treatment.

Lessons from Vessel Wall Imaging of Intracranial Aneurysms: New Era of Aneurysm Evaluation beyond Morphology.

Recent basic studies have clarified that aneurysmal wall inflammation plays an important role in the pathophysiology of intracranial aneurysms. However, it remains an interdisciplinary challenge to visualize aneurysm wall status in vivo. MR-vessel wall imaging (VWI) is a current topic of advanced imaging techniques since it could provide an additional value for unruptured intracranial aneurysms (UIAs) risk stratification. With regard to ruptured intracranial aneurysms, VWI could identify a ruptured aneurysm in patients with multiple intracranial aneurysms. Intraluminal thrombus could be a clue to interpret aneurysm wall enhancement on VWI in ruptured intracranial aneurysms. The interpretation of VWI findings in UIAs would require much caution. Actually aneurysm wall enhancement in VWI was significantly associated with consensus morphologic risk factors. However, aneurysmal wall with contrast enhancement oftentimes associated with atherosclerotic, degenerated and thickened wall structure. It remains ill defined if thin wall without wall enhancement (oftentimes invisible in VWI) could be actually safe or look over wall vulnerability. We reviewed currently available studies, especially focusing on VWI for intracranial aneurysms and discussed the clinical utility of VWI.

Vessel Wall Imaging Predicts the Presence of Atherosclerotic Lesions in Unruptured Intracranial Aneurysms.

BACKGROUND: Recent studies have suggested that magnetic resonance vessel wall imaging (VWI) can visualize thickened intracranial aneurysm wall. We aimed to investigate correlations between VWI findings and intraoperative aneurysm wall features based on the hypothesis that VWI can visualize atherosclerotic changes in unruptured intracranial aneurysm (UIA) walls. METHODS: A total of 36 microsurgically treated UIAs were retrospectively reviewed. All aneurysms underwent VWI before microsurgical clipping, and fusion images with time-of-flight magnetic resonance angiography were created to localize aneurysm wall enhancement (AWE) lesions. Intraoperatively, 2 neurosurgeons who were blinded to the VWI findings evaluated the aneurysm wall features, giving each aneurysm an atherosclerosis score on a 5-point scale (5: yellowish, 4: whitish, 3: normal, 2: slightly reddish, 1: reddish). We defined atherosclerotic lesions as those having average scores ≥4. We evaluated the rate of correspondence between AWE lesions and atherosclerotic lesions, and the factors associated with AWE. RESULTS: Sixteen of the 36 UIAs (44%) were identified as AWE. The sensitivity, specificity, positive predictive value, and negative predictive value of correspondence between AWE lesions and atherosclerotic lesions were 79%, 94%, 94%, and 80%, respectively. The average atherosclerosis scores (4.2 ± 0.5 vs. 2.7 ± 0.9; P < 0.001) were significantly higher in aneurysms with AWE. Twelve of 16 UIAs with wall enhancement had wall thinning adjacent to the part with AWE. CONCLUSIONS: AWE lesions corresponded with intraoperatively confirmed atherosclerotic lesions of UIAs. Detecting these lesions would be valuable in exploring UIAs with wall degeneration.