Occipital artery to vertebral artery bypass for treatment of bilateral vertebral artery occlusion with QMRA as an adjunct to diagnostic assessment.

PURPOSE: Stroke, the second leading cause of death globally, often involves ischemia in the vertebrobasilar territory. This condition is underexplored, despite significant morbidity and mortality risks. The purpose of this study is to present a case of occipital artery to V3 segment vertebral artery bypass, emphasizing the role of quantitative magnetic resonance angiography (qMRA) in assessing flow and guiding surgical intervention. METHODS: A 66-year-old man with bilateral vertebral artery occlusion presented acute symptoms. qMRA was employed to evaluate flow dynamics and determine the feasibility of a flow augmentation bypass surgery. The occipital artery to left vertebral artery bypass (OA-to-VA) was performed, utilizing an inverted hockey-stick incision and an antegrade inside-out technique. The patency of the bypass was confirmed using both Doppler probe and Indocyanine green. RESULTS: Postoperative assessments, including computed tomography angiography (CTA) and qMRA, demonstrated the patency of the bypass with improved flow in the basilar artery and left vertebral artery. The patient's condition remained stable postoperatively, with residual peripheral palsy of the left facial nerve. CONCLUSION: In conclusion, the presented case illustrates the efficacy of the OA-to-VA bypass in addressing symptomatic bilateral vertebral artery occlusion. The study underscores the pivotal role of qMRA in pre- and postoperative assessments, providing noninvasive flow quantification for diagnostic considerations and long-term follow-up in patients with vertebrobasilar insufficiency.

Magnetic Resonance Imaging/Angiography Versus Catheter Angiography for Annual Follow-up of Pediatric Moyamoya Patients: A Cost Outcomes Analysis.

BACKGROUND: Digital subtraction angiography (DSA) assesses revascularization in pediatric moyamoya patients after surgery, but MRI and angiography (MRI/A) may provide comparable data. OBJECTIVE: To evaluate DSA and MRI/A with respect to clinical utility in postoperative follow-up, complication profile, and relative cost at 1 year. METHODS: All pediatric moyamoya patients who received bilateral indirect revascularization between 2011 and 2020 were retrospectively reviewed at 1 institution. Patients who underwent MRI/A-only, DSA-only, or both after 1 year were compared. RESULTS: Eighty-two patients were included. At 1 year, patients who underwent either MRI/A (n = 29) or DSA (n = 40) had no significant differences in detection rate of new at-risk hypovascular territories (6.9% vs 2.5%, P = .568) or need for subsequent revascularization beyond the mean 40 ± 24-month follow-up period (3.4% vs 5.0%, P > .9). Among patients who underwent both MRI/A and DSA (n = 13), both studies identified the same at-risk territories. No patients experienced MRI/A-related complications, compared with 3 minor DSA-related complications. The use of MRI/A yielded a 6.5-fold reduction in cost per study vs DSA at 1 year. CONCLUSION: Using DSA to follow moyamoya patients after indirect revascularization is generally safe but associated with a low rate of minor complications and a 6.5-fold greater financial cost relative to MRI/A. These data support changing practice to eliminate the use of DSA when following routine bilateral moyamoya cases in the absence of clinical symptoms or specific concerns. Using MRI/A as the primary postoperative follow-up modality in this select population provides noninferior care and greater patient access, while reducing cost and potentially decreasing risk.

Efficacy assessment of superficial temporal artery-middle cerebral artery bypass surgery in treating moyamoya disease from a hemodynamic perspective: a pilot study using computational modeling and perfusion imaging.

BACKGROUND: Superficial temporal artery-middle cerebral artery (STA-MCA) bypass is a common surgery in treating moyamoya disease (MMD) with occluded MCA. Computational fluid dynamics (CFD) simulation might provide a simple, non-invasive, and low-cost tool to evaluate the efficacy of STA-MCA surgery. AIM: We aim to quantitatively investigate the treatment efficacy of STA-MCA surgery in improving the blood flow of MMD patients using CFD simulation. METHODS: This retrospective study included 11 MMD patients with occlusion around proximal MCA who underwent STA-MCA bypass surgery. CFD simulation was performed using patient-specific blood pressure and postoperative artery geometry. The volumetric flow rates of STA and the bypass, average flow velocity in the proximal segment of transcranial bypass, transcranial pressure drop, and transcranial flow resistance were measured and compared with a postoperative increment of cerebral blood flow (CBF) in MCA territories derived from perfusion imaging. Per-branch pressure drop from model inlet to bypass branch outlet was calculated. RESULTS: The volumetric flow rates of STA and the bypass were 80.84 ± 14.54 mL/min and 46.03 ± 4.21 mL/min. Average flow velocity in proximal bypass, transcranial pressure drop, and transcranial flow resistance were 0.19 ± 0.07 m/s, 3.72 ± 3.10 mmHg, and 6.54 ± 5.65 10-8 Pa s m-3. Postoperative mean increment of CBF in MCA territories was 16.03 ± 11.72 mL·100 g-1·min-1. Per-branch pressure drop was 10.96 ± 5.59 mmHg and 7.26 ± 4.25 mmHg in branches with and without stenosis. CONCLUSIONS: CFD simulation results are consistent with CBF observation in verifying the efficacy of STA-MCA bypass, where postoperative stenosis may influence the hemodynamics.

Seven bypasses simulation set: description and validity assessment of novel models for microneurosurgical training.

OBJECTIVE: Microsurgical training remains indispensable to master cerebrovascular bypass procedures, but simulation models for training that accurately replicate microanastomosis in narrow, deep-operating corridors are lacking. Seven simulation bypass scenarios were developed that included head models in various surgical positions with premade approaches, simulating the restrictions of the surgical corridors and hand positions for microvascular bypass training. This study describes these models and assesses their validity. METHODS: Simulation models were created using 3D printing of the skull with a designed craniotomy. Brain and external soft tissues were cast using a silicone molding technique from the clay-sculptured prototypes. The 7 simulation scenarios included: 1) temporal craniotomy for a superficial temporal artery (STA)-middle cerebral artery (MCA) bypass using the M4 branch of the MCA; 2) pterional craniotomy and transsylvian approach for STA-M2 bypass; 3) bifrontal craniotomy and interhemispheric approach for side-to-side bypass using the A3 branches of the anterior cerebral artery; 4) far lateral craniotomy and transcerebellomedullary approach for a posterior inferior cerebellar artery (PICA)-PICA bypass or 5) PICA reanastomosis; 6) orbitozygomatic craniotomy and transsylvian-subtemporal approach for a posterior cerebral artery bypass; and 7) extended retrosigmoid craniotomy and transcerebellopontine approach for an occipital artery-anterior inferior cerebellar artery bypass. Experienced neurosurgeons evaluated each model by practicing the aforementioned bypasses on the models. Face and content validities were assessed using the bypass participant survey. RESULTS: A workflow for model production was developed, and these models were used during microsurgical courses at 2 neurosurgical institutions. Each model is accompanied by a corresponding prototypical case and surgical video, creating a simulation scenario. Seven experienced cerebrovascular neurosurgeons practiced microvascular anastomoses on each of the models and completed surveys. They reported that actual anastomosis within a specific approach was well replicated by the models, and difficulty was comparable to that for real surgery, which confirms the face validity of the models. All experts stated that practice using these models may improve bypass technique, instrument handling, and surgical technique when applied to patients, confirming the content validity of the models. CONCLUSIONS: The 7 bypasses simulation set includes novel models that effectively simulate surgical scenarios of a bypass within distinct deep anatomical corridors, as well as hand and operator positions. These models use artificial materials, are reusable, and can be implemented for personal training and during microsurgical courses.

Intracranial-Intracranial Bypass for Aneurysms: Quantitative Intraoperative Assessment of Flow Preservation.

BACKGROUND: Intraoperative flow measurement has proven utility in extracranial-intracranial bypass, particularly in assessing the adequacy of donors by measurement of cut flow. The nature of intracranial-intracranial (IC-IC) bypass precludes cut flow measurement, but quantitative intraoperative flow measurements may evaluate augment assessment of the bypass. OBJECTIVE: To retrospectively evaluate flow measurements performed in IC-IC bypass to determine the adequacy of the constructs in preserving flow. METHODS: With institutional review board approval, we performed a retrospective review of our bypass database from 2001 to 2021 for aneurysms treated with IC-IC bypass and with intraoperative flow measurements. Patients' preoperative characteristics, bypass indications, prebypass and postbypass intraoperative flow measurements, and patient outcomes were recorded. RESULTS: Of 346 bypasses, 21 cases using 22 IC-IC bypasses were included. The median age was 55 years; 13 of 21 cases were ruptured aneurysms. Aneurysms involved posterior inferior cerebellar artery (n = 7), middle cerebral artery (n = 6), distal anterior cerebral artery (n = 5), and anterior communicating artery (n = 3). Six bypasses were end-to-side (ETS), 10 were side-to-side (STS), and 6 were excisional with reanastomosis (end-to-end, ETE). Intraoperatively, 21 of the bypasses were patent; the postbypass/prebypass flow index averaged 1.15 (±0.32): ETE (n = 6) 1.22 ± 0.34 and ETS/STS bypasses (n = 15) 1.11 ± 0.32. All intraoperatively patent bypasses were patent on postoperative angiography. One occluded on delayed angiography without clinical sequelae. CONCLUSION: Despite advances in endovascular therapy, IC-IC bypass remains essential to the treatment of large and fusiform aneurysms. We demonstrate quantitatively that IC-IC donors provide adequate direct (ETE) and redistributed (STS ETS) flow to the recipient territory. Flow measurement provides valuable information regarding the patency and adequacy of IC-IC bypass for flow preservation.

Cost-Effectiveness Analysis of Encephaloduroarteriosynangiosis Surgery for Symptomatic Intracranial Atherosclerotic Disease.

Encephaloduroarteriosynangiosis (EDAS) is a promising treatment for cerebral arterial steno-occlusive disorders, with proven efficacy in moyamoya disease and a growing interest in potential application for patients with symptomatic intracranial atherosclerotic disease, given the early results of intermediate development trials showing reduced rates of recurrence stroke and improved clinical outcomes compared with those patients treated with intense medical management (IMM) alone. Although clinical outcomes are the fundamental goal when considering patient care paradigms, a cost-effective analysis is key to obtaining a comprehensive understanding of the impact EDAS may provide to patients with atherosclerotic disease on a larger scale. Here, we evaluate the EDAS + IMM cost-effectiveness over time in the treatment of intracranial atherosclerotic disease compared with IMM alone.

Quality of life impairment in adult Moyamoya patients-preoperative neuropsychological assessment and correlation to MRI and H215O PET findings.

Moyamoya angiopathy (MMA) related cerebral perfusion deficits or infarctions might influence quality of life (QoL). This study examines preoperative QoL in adult patients with MMA and correlates these with findings obtained via diagnostic imaging. Sixty-seven adult Moyamoya patients underwent preoperative neuropsychological testing including questionnaires to determine QoL, as well as psychiatric and depressive symptoms. The results were checked for correlation with territorial hypoperfusions seen in H215O PET with acetazolamide (ACZ) challenge (cerebrovascular reserve) and infarction patterns observed in MRI. Each vascular territory was analyzed separately and correlated with QoL. Physical role function was restricted in 41.0% of cases and emotional role function in 34.4% of cases (SF-36). Obsessive-compulsive disorder (39.3%) (SCL-90-R), psychoticism (34.4%) (SCL-90-R), and depression (32.7%) (BDI-II) were also very common. Psychoticism was significantly more frequent in cases where perfusion deficits in PET CT were observed in both MCA territories (left p = 0.0124, right p = 0.0145) and infarctions in MRI were present in the right MCA territory (p = 0.0232). Depression was significantly associated with infarctions in the right MCA territory (SCL-90-R p = 0.0174, BDI-II p = 0.0246). Women were affected more frequently by depression (BDI-II, p = 0.0234). Physical role function impairment was significantly associated with perfusion deficits in the left MCA territory (p = 0.0178) and infarctions in the right MCA territory (p = 0.0428). MMA leads to impairments in different areas of QoL. Approximately one-third of all adult MMA patients suffered from depression, with women being most affected. In addition to depression, presence of executive dysfunctions and mental disorders such as psychoticism, obsessive-compulsive disorder, and impaired physical and emotional role function affected QoL. These patients showed significantly more often infarctions and perfusion deficits in the right MCA territory. Long-term studies with follow-up results are necessary to clarify a possible beneficial impact of early surgical revascularization on QoL and depression in adult MMA patients.

Arterial spin labeling as an ancillary assessment to postoperative conventional angiogram in pediatric moyamoya disease.

OBJECTIVE: Digital subtraction angiography (DSA) is commonly performed after pial synangiosis surgery for pediatric moyamoya disease to assess the degree of neovascularization. However, angiography is invasive, and the risk of ionizing radiation is a concern in children. In this study, the authors aimed to identify whether arterial spin labeling (ASL) can predict postoperative angiogram grading. In addition, they sought to determine whether patients who underwent ASL imaging without DSA had similar postoperative outcomes when compared with patients who received ASL imaging and postoperative DSA. METHODS: The medical records of pediatric patients who underwent pial synangiosis for moyamoya disease at a quaternary children's hospital were reviewed during a 10-year period. ASL-only and ASL+DSA cohorts were analyzed. The frequency of preoperative and postoperative symptoms was analyzed within each cohort. Three neuroradiologists assigned a visual ASL grade for each patient indicating the change from the preoperative to postoperative ASL perfusion sequences. A postoperative neovascularization grade was also assigned for patients who underwent DSA. RESULTS: Overall, 21 hemispheres of 14 patients with ASL only and 14 hemispheres of 8 patients with ASL+DSA were analyzed. The groups had similar rates of MRI evidence of acute or chronic stroke preoperatively (61.9% in the ASL-only group and 64.3% in the ASL+DSA group). In the entire cohort, transient ischemic attack (TIA) (p = 0.027), TIA composite (TIA or unexplained neurological symptoms; p = 0.0006), chronic headaches (p = 0.035), aphasia (p = 0.019), and weakness (p = 0.001) all had decreased frequency after intervention. The authors found a positive association between revascularization observed on DSA and the visual ASL grading (p = 0.048). The visual ASL grades in patients with an angiogram indicating robust neovascularization demonstrated improved perfusion when compared with the ASL grades of patients with a poor neovascularization. CONCLUSIONS: Noninvasive ASL perfusion imaging had an association with postoperative DSA neoangiogenesis following pial synangiosis surgery in children. There were no significant postoperative stroke differences between the ASL-only and ASL+DSA cohorts. Both cohorts demonstrated significant improvement in preoperative symptoms after surgery. Further study in larger cohorts is necessary to determine whether the results of this study are validated in order to circumvent the invasive catheter angiogram.

Assessment of Surgical Outcomes in Children and Adult Ischemic Moyamoya Disease and Its Relationship with the Pre-infarction Cerebral Perfusion Status.

AIM: To clarify perfusion differences, and to determine whether children and adults respond similarly to surgical prevention and how brain perfusion stages before surgery predict outcomes in ischaemic moyamoya disease (MMD) in children and adults. MATERIAL AND METHODS: A total of 355 patients with ischaemic MMD, including 74 children and 281 adults, were enrolled in the study. Computerized tomography perfusion (CTP) scans were used to identify the perfusion status according to a novel staging system of the pre-infarction period. The perfusion status of each hemisphere between the children and adult groups was analysed. The modified Rankin scale was used during long-term follow-up as an indicator of clinical outcomes. RESULTS: The proportions of stages 0 and IV in adults were significantly higher than those in children (p=0.09 and p=0.003, respectively). Stage III was more common in the children's group (p=0.001). The stroke data showed an increasing tendency in the infarction rate from stages I to IV. Both groups in stage 0 and in the early stages had a similar highly improved ratio after surgery; the children, however, achieved significantly better clinical outcomes in stage III and late stages. CONCLUSION: There are differences in the perfusion status between child and adult patients with MMD. The pre-infarction staging system is associated with MMD-related stroke to some extent. Children have a greater chance for improvement than adults in stage III and later stages.

Socioeconomic Inequities in the Surgical Management of Moyamoya Disease.

BACKGROUND: Given the vasculopathic nature of moyamoya disease (MMD) and high susceptibility to ischemic events, patients with MMD often require surgical revascularization via an indirect or direct bypass, and analysis of disparities in receipt of appropriate management is critical. METHODS: The 2012-2016 Nationwide Inpatient Sample was queried for patients admitted with a diagnosis of MMD using International Classification of Diseases codes. Patient baseline demographics, hospital characteristics, and associated symptoms were collected. Patients were grouped by receipt of bypass procedure, and propensity score matching was performed to identify socioeconomic disparities between operative and nonoperative groups. RESULTS: Inclusion criteria were met by 4474 patients (827 pediatric patients and 3647 adult patients). Mean (SD) age for pediatric patients was 10.4 (4.6) years and for adult patients was 40.5 (14.4) years. Among pediatric patients, Black and Hispanic/Latino patients were less likely to undergo revascularization surgery (odds ratio [OR] 0.49, 95% confidence interval [CI] 0.21-0.78, P ≤ 0.01; OR 0.47, 95% CI 0.26-0.84, P = < 0.01, respectively); among adult patients, Black and Hispanic/Latino patients were similarly less likely to undergo bypass procedures (OR 0.60, 95% CI 0.49-0.72, P ≤ 0.01; OR 0.73, 95% CI 0.55-0.96, P = 0.01, respectively). Pediatric and adult patients in the lowest and next to lowest income quartiles were also less likely to receive operative treatment (pediatric patients: OR 0.61, 95% CI 0.40-0.94, P = 0.02; OR 0.64, 95% CI 0.42-0.98, P = 0.04, respectively; adult patients: OR 0.82, 95% CI 0.88-0.98, P = 0.03). CONCLUSIONS: Further investigation into socioeconomic disparities in adult and pediatric patients with MMD is warranted given the potential for inequities in access to appropriate intervention.

Assessment of cerebrovascular reserve with N-isopropyl-p-[123I]-iodoamphetamine time series analysis in patients with cerebrovascular disease.

ABSTRACT: Using N-isopropyl-p-[123I]-iodoamphetamine(123I-IMP) and single-photon emission computed tomography (SPECT), the relationship between cerebrovascular reserve and the 123I-IMP redistribution phenomenon was investigated.The 50 patients who matched the inclusion criteria were divided into control and ischemia groups, and the redistribution phenomenon was examined on resting images. The delayed images showed higher 123I-IMP accumulation in lesions in the middle cerebral artery(MCA) area and anterior cerebral artery(ACA) area, these watershed areas in the ischemia group than in the control group, confirming that the redistribution phenomenon exists with statistical significance (Wilcoxon test; control group vs ischemic group in the ACA area[P = .002], ACA-MCA watershed area(P = .014), MCA area(P = .025), and MCA-posterior cerebral artery(PCA) watershed area(P = .002). The patients were then divided into 4 types according to the Kuroda grading system, and the difference in the redistribution phenomenon was investigated between type III and the other 3 types.Compared with type I and type II, type III had a significantly lower rate of decrease in the radioisotope (RI) count, verifying the redistribution phenomenon (Student t test: type I vs type III in the ACA area(P = .008), ACA-MCA watershed area(P = .009), MCA area(P < .001), and MCA-PCA watershed area(P = .002); type II vs type III in the ACA area(P = .004), ACA-MCA watershed area(P = .2575), MCA area(P < .001), and MCA-PCA watershed area(P < .001). No significant difference between type III and type IV was observed in any area [(Student t test: type III vs type IV in the ACA area(P = .07), ACA-MCA watershed area(P = .38), MCA area(P = .05), and MCA-PCA watershed area(P = .24)].The redistribution phenomenon is associated with resting cerebral blood flow (CBF), but not necessarily with cerebral vascular reactivity (CVR).

Editor's Choice - Risk of Stroke before Revascularisation in Patients with Symptomatic Carotid Stenosis: A Pooled Analysis of Randomised Controlled Trials.

OBJECTIVE: Current guidelines recommending rapid revascularisation of symptomatic carotid stenosis are largely based on data from clinical trials performed at a time when best medical therapy was potentially less effective than today. The risk of stroke and its predictors among patients with symptomatic carotid stenosis awaiting revascularisation in recent randomised controlled trials (RCTs) and in medical arms of earlier RCTs was assessed. METHODS: The pooled data of individual patients with symptomatic carotid stenosis randomised to stenting (CAS) or endarterectomy (CEA) in four recent RCTs, and of patients randomised to medical therapy in three earlier RCTs comparing CEA vs. medical therapy, were compared. The primary outcome event was any stroke occurring between randomisation and treatment by CAS or CEA, or within 120 days after randomisation. RESULTS: A total of 4 754 patients from recent trials and 1 227 from earlier trials were included. In recent trials, patients were randomised a median of 18 (IQR 7, 50) days after the qualifying event (QE). Twenty-three suffered a stroke while waiting for revascularisation (cumulative 120 day risk 1.97%, 95% confidence interval [CI] 0.75 - 3.17). Shorter time from QE until randomisation increased stroke risk after randomisation (χ2 = 6.58, p = .011). Sixty-one patients had a stroke within 120 days of randomisation in the medical arms of earlier trials (cumulative risk 5%, 95% CI 3.8 - 6.2). Stroke risk was lower in recent than earlier trials when adjusted for time between QE and randomisation, age, severity of QE, and degree of carotid stenosis (HR 0.47, 95% CI 0.25 - 0.88, p = .019). CONCLUSION: Patients with symptomatic carotid stenosis enrolled in recent large RCTs had a lower risk of stroke after randomisation than historical controls. The added benefit of carotid revascularisation to modern medical care needs to be revisited in future studies. Until then, adhering to current recommendations for early revascularisation of patients with symptomatic carotid stenosis considered to require invasive treatment is advisable.

Comparative Assessment of Extracranial-to-Intracranial and Intracranial-to-Intracranial In Situ Bypass for Complex Intracranial Aneurysm Treatment Based on Rupture Status: A Case Series.

BACKGROUND: Comparative outcomes of extracranial-to-intracranial (EC-IC) and intracranial-to-intracranial (IC-IC) bypass for complex aneurysm treatment based on rupture status are not well described in the literature. In this study, we compare outcomes of EC-IC and IC-IC bypass for complex intracranial aneurysm treatment based on rupture status. METHODS: A prospective neurosurgical patient database was retrospectively reviewed. Sixty-three consecutive patients with aneurysm managed with revascularization were identified between July 2014 and December 2018. RESULTS: During the study period, 41 patients with aneurysm underwent EC-IC bypass (65%; 24 [58.5%] ruptured, 17 [41.5%] unruptured) and 22 patients with aneurysm underwent IC-IC bypass (34.9%; 13 [59.1%] ruptured, 9 [40.9%] unruptured). Graft spasm occurred in 4 patients (9.8%) in the EC-IC group (all ruptured aneurysms) and all anastomoses were patent on immediate postoperative imaging. Perioperative mortality occurred in 5 patients who underwent EC-IC bypass (12.2%; 3 ruptured, 2 unruptured) EC-IC and 2 patients who underwent IC-IC bypass (9.1%; both ruptured); (P = 0.709). Bypass-related complications occurred only in patients with ruptured aneurysm (2 [8.3%] in the EC-IC group and 0 [0%] in the IC-IC group; P = 0.285). For unruptured aneurysms, the overall complication rate was lower in IC-IC compared with the EC-IC group (P = 0.006). Modified Rankin Scale scores on discharge were significantly lower in IC-IC compared with EC-IC bypass for unruptured aneurysms (P = 0.008). There was a trend for shorter temporary occlusion and hospitalization times and overall better outcomes with IC-IC compared with EC-IC bypass. CONCLUSIONS: Although often considered riskier than EC-IC bypass, IC-IC in situ bypass showd a favorable technical and safety profile for the treatment of complex, unruptured aneurysms.

Non-invasive assessment of cerebral microvascular changes for predicting postoperative cerebral hyperperfusion after surgical revascularisation for moyamoya disease: an arterial spin labelling MRI study.

PURPOSE: Cerebral hyperperfusion syndrome (CHPS) can result after anastomotic surgery as the reperfusion is established in chronically ischemic cerebral territories in patients of moyamoya disease (MMD). In this study, we have evaluated the feasibility of arterial spin labelling (ASL) perfusion MRI to predict cerebral hyperperfusion syndrome based on changes of cerebral blood flow (CBF) after revascularisation surgery in patients of MMD. METHODS: Our prospective study included 25 patients with MMD who underwent superficial temporal artery-middle cerebral artery (STA-MCA) bypass with or without dural/muscle synangiosis. ASL MRI was performed before and 1-7 days after surgery. On the side planned for operation, 5-mm ROI circle was drawn on the predetermined regions in frontal lobe, temporal lobe, parietal lobe and basal ganglia in proximal and distal territories of MCA to calculate ipsilateral CBF values (CBFi). An attempt was made to select the same location on contralateral side (non-operative) (CBFc) for each measurement for calculation of hemispheric normalised CBF (nCBFh) ratios. To adjust for inter individual variation among MR imagers and CBF, additional regions of interest were drawn within the cerebellum (CBFcbl) for cerebellar CBF normalised ratios (nCBFCbl). RESULTS: Of the 25 patients (26 operated hemispheres), 5 patients showed significant immediate postoperative symptoms suggestive of CHPS. Based on our findings, sensitivity and specificity of ASL perfusion to detect CHPS were evaluated. ASL was found to have 47-100% sensitivity and 45-88% specificity to detect CHPS. We have tried to calculate the prevalence of CHPS in postoperative patients of moyamoya disease, which in our study ranged from 6.83 to 40.70%. CONCLUSION: Based on our results, we concluded that ASL perfusion is an appropriate alternative to standard nuclear medicine studies to monitor the changes in perfusion after STA-MCA bypass surgery in moyamoya patients. ASL MR perfusion can be used to identify changes in cerebral blood flow (CBF) for early detection of cerebral hyperperfusion syndrome in patients with otherwise normal conventional MRI sequences with very high sensitivity but moderate specificity.

Assessment of Transient Cerebral Hemodynamic Disturbance via Whole-Brain Computed Tomography Perfusion After Extracranial-Intracranial Bypass in Ischemic Moyamoya Disease.

OBJECTIVE: To assess the cerebral hemodynamic data associated with transient cerebral hemodynamic disturbance (TCHD), including cerebral hyperperfusion syndrome (CHS) and watershed shift ischemia (WSI), by whole-brain (WB) computed tomography perfusion (CTP) before and after revascularization for ischemic moyamoya disease. METHODS: A total of 115 consecutive patients with ischemic moyamoya disease underwent revascularization. All patients underwent WB-CTP 24 hours before operation and on the day of onset of TCHD and 6 months after revascularization. The volumes of delay time (DT) >3 seconds and mismatch and relative cerebral blood flow <30% were calculated in 3 time points. RESULTS: Of the 115 patients, 18 115 had TCHD, comprising 10 with CHS and 8 with WSI. Compared with the brain volume of DT >3 seconds before revascularization, the volume decreased significantly (P < 0.05) on the day of CHS. The volume of mismatch in 3 time points indicated no significant differences (P > 0.05). The volume of relative cerebral blood flow <30% showed obvious differences of significance among 10 patients with CHS (P < 0.05) at 3 time points. In the WSI group, the volume of DT >3 seconds, mismatch, and DT >3 seconds showed significant differences, relatively (P < 0.05), at 3 time points. At the time of onset of TCHD, DT >3 seconds and mismatch in the CHS group were dramatically lower than those in the WSI group (P < 0.05). DT >3 seconds in the no-TCHD group showed significant differences (P < 0.05) at 3 time points. CONCLUSIONS: WB-CTP could be used to assess the cerebral hemodynamic characteristics before and after revascularization. DT >3 seconds and mismatch played important roles in evaluating distinct features of TCHD.

Safety, Feasibility, and Patient-Rated Outcome of Sonolucent Cranioplasty in Extracranial-Intracranial Bypass Surgery to Allow for Transcranioplasty Ultrasound Assessment.

OBJECTIVE: We sought to analyze the safety and feasibility of elective sonolucent cranioplasty in the setting of extracranial-to-intracranial (EC-IC) bypass surgery to monitor bypass patency using ultrasound. METHODS: Patients who underwent direct EC-IC bypass surgery agreed to sonolucent cranioplasty at the time of surgery and received a sonolucent polymethyl methacrylate (PMMA) implant. Besides monitoring clinical outcome, all patients received transcranioplasty ultrasound (TCUS) on postoperative day 1 and at last follow-up. In addition, bypass patency was confirmed using catheter angiogram and fit of implant using computed tomography. Patient-rated outcome was assessed through phone questionnaire. RESULTS: EC-IC bypass surgery with PMMA cranioplasty was successful in all 7 patients with patent bypasses on postoperative angiogram. Direct TCUS was feasible in all patients, and bypass patency was monitored. There were no complications such as postoperative hemorrhagic/ischemic complications related to the bypass procedure in this patient population, as well as no complications related to the PMMA implant. Postoperative computed tomography showed favorable cosmetic results of the PMMA implant in both the pterional area for superficial temporal artery-middle cerebral artery bypasses and parietooccipital area for occipital artery-middle cerebral artery bypasses as confirmed by high-rated overall patient satisfaction with favorable cosmetic, pain, and sensory patient-rated outcomes. CONCLUSIONS: In this study we were able to show that this novel technique is safe, allows for patency assessment of the EC-IC bypass using bedside TCUS technique, and is cosmetically satisfying for patients.

Implications of achieving TICI 2b vs TICI 3 reperfusion in patients with ischemic stroke: a cost-effectiveness analysis.

BACKGROUND: The benefit of endovascular thrombectomy (EVT) in stroke patients with large-vessel occlusion (LVO) depends on the degree of recanalization achieved. We aimed to determine the health outcomes and cost implications of achieving TICI 2b vs TICI 3 reperfusion in acute stroke patients with LVO. METHODS: A decision-analytic study was performed with Markov modeling to estimate the lifetime quality-adjusted life years (QALY) of EVT-treated patients, and costs based on the degree of reperfusion achieved. The study was performed with a societal perspective in the United States' setting. The base case calculations were performed in three age groups: 55-, 65-, and 75-year-old patients. RESULTS: Within 90 days, achieving TICI 3 resulted in a cost saving of $3676 per patient and health benefit of 11 days in perfect health as compared with TICI 2b. In the long term, for the three age groups, achieving TICI 3 resulted in cost savings of $46,498, $25,832, and $15 719 respectively, and health benefits of 2.14 QALYs, 1.71 QALYs, and 1.23 QALYs. Every 1% increase in TICI 3 in 55-year-old patients nationwide resulted in a cost saving of $3.4 million and a health benefit of 156 QALYs. Among 65-year-old patients, the corresponding cost savings and health benefit were $1.9 million and 125 QALYs. CONCLUSION: There are substantial cost and health implications in achieving complete vs incomplete reperfusion after EVT. Our study provides a framework to assess the cost-benefit analysis of emerging diagnostic and therapeutic techniques that might improve patient selection, and increase the chances of achieving complete reperfusion.

Spontaneous Thrombosis of Giant Dissecting Fusiform Middle Cerebral Aneurysm After Double-Barrel Superficial Temporal Artery-Middle Cerebral Artery Bypass: A Case Report of Decision-Making in a Limited Resource Environment.

BACKGROUND: The treatment of giant fusiform middle cerebral artery (MCA) aneurysms remains daunting owing to their tendency to be associated with precarious end-vessel anatomy and the need for complex microsurgical techniques to appropriately address the aneurysm and the vasculature at risk. Extracranial-intracranial bypass revascularization remains a valuable tool for treating these complex lesions. In the present report, we have described a rare occurrence in which the creation of a double-barrel superficial temporal artery (STA-MCA) bypass facilitated spontaneous obliteration of the aneurysm. We have also highlighted our decision-making process, which was affected by operating in a low-to-middle income country with limited resources. CASE DESCRIPTION: A 32-year-old man had presented with recurrent ischemic events in the left MCA distribution and subsequent subarachnoid hemorrhage due to rupture of a giant complex fusiform MCA aneurysm. The patient underwent double-barrel STA-MCA bypass and was scheduled for second-stage clip reconstruction or partial trapping. Postoperative imaging studies revealed progressive thrombosis of the M1 segment, resulting in occlusion of the aneurysm without subsequent trapping or clipping. The patient recovered remarkably without further repeat hemorrhage or ischemic injury. We also reviewed the reported data. CONCLUSIONS: Double-barrel STA-MCA bypass is a potential salvage surgical technique to treat selected ruptured complex giant fusiform MCA aneurysms. In rare selected cases, the flow alteration induced by the bypass alone can potentially facilitate aneurysm thrombosis.