Bypass Surgery For Moyamoya Disease Research Articles

Multi-parameter MRI-Based Machine Learning Model to Evaluate the Efficacy of STA-MCA Bypass Surgery for Moyamoya Disease: A Pilot Study.

Superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery represents the primary treatment for Moyamoya disease (MMD), with its efficacy contingent upon collateral vessel development. This study aimed to develop and validate a machine learning (ML) model for the non-invasive assessment of STA-MCA bypass surgery efficacy in MMD. This study enrolled 118 MMD patients undergoing STA-MCA bypass surgery. Clinical features were screened to construct a clinical model. MRI features were extracted from the middle cerebral artery supply area using 3D Slicer and employed to build five ML models using logistic regression algorithm. The combined model was developed by integrating the radiomics score (Rad-score) with the clinical features. Model performance validation was conducted using ROC curves. Platelet count (PLT) was identified as a significant clinical feature for constructing the clinical model. A total of 3404 features (851 × 4) were extracted, and 15 optimal features were selected from each MRI sequence as predictive factors. Multivariable logistic regression identified PLT and Rad-score as independent parameters used for constructing the combined model. In the testing set, the AUC of the T1WI ML model [0.84 (95% CI, 0.70-0.97)] was higher than that of the clinical model [0.66 (95% CI, 0.46-0.86)] and the combined model [0.80 (95% CI, 0.66-0.95)]. The T1WI ML model can be used to assess the postoperative efficacy of STA-MCA bypass surgery for MMD.

3D exoscopic versus microscopic superficial temporal artery to middle cerebral artery bypass surgery for moyamoya disease – a comparative series

PurposeSuperficial temporal artery to middle cerebral artery (STA-MCA) direct bypass surgery is the most common surgical procedure to treat moyamoya disease (MMD). Here, we aim to compare the performance of the 3D exoscope in bypass surgery with the gold standard operative microscope.MethodsAll direct STA-MCA bypass procedures performed at a single university hospital for MMD between 2015 and 2023 were considered for inclusion. Data were retrospectively collected from patient files and surgical video material. From 2020 onwards, bypass procedures were exclusively performed using a digital three-dimensional exoscope as visualization device. Results were compared with a microsurgical bypass control group (2015–2019). The primary endpoint was defined as total duration of surgery, duration of completing the vascular anastomosis (ischemia time), bypass patency, number of stiches to perform the anastomosis, added stiches after leakage testing of the anastomosis and the Glasgow outcome scale (GOS) at last follow-up as secondary outcome parameter.ResultsA total of 16 consecutive moyamoya patients underwent 21 STA-MCA bypass procedures. Thereof, six patients were operated using a microscope and ten patients using an exoscope (ORBEYE® n = 1; AEOS® n = 9).Total duration of surgery was comparable between devices (microscope: 313 min. ± 116 vs. exoscope: 279 min. ± 42; p = 0.647). Ischemia time also proved similar between groups (microscope: 43 min. ± 19 vs. exoscope: 41 min. ± 7; p = 0.701). No differences were noted in bypass patency rates. The number of stiches per anastomosis was similar between visualization devices (microscope: 17 ± 4 vs. exoscope: 17 ± 2; p = 0.887). In contrast, more additional stiches were needed in microscopic anastomoses after leakage testing the bypass (p = 0.035).ConclusionTaking into account the small sample size, end-to-side bypass surgery for moyamoya disease using a foot switch-operated 3D exoscope was not associated with more complications and led to comparable clinical and radiological results as microscopic bypass surgery.

Assessing donor-recipient arterial pressure dynamics in STA-MCA bypass for moyamoya disease

BackgroundIn bypass surgery for moyamoya disease (MMD), the superficial temporal artery’s (STA) pressure needs to surpass that of the cortical M4 recipient of the middle cerebral artery (MCA), boosting cerebral blood flow into the MCA and enhancing cerebral circulation. This study investigates the STA-MCA arterial pressure parameters and gradients during bypass surgery, aiming to deepen our understanding of hemodynamic shifts pre- and post-operation.MethodsDSA imaging data were prospectively collected from patients diagnosed with bilateral MMD who underwent STA-MCA bypass surgery between 2022 and 2023 and stratified according to the Suzuki stage. The mean arterial pressure (MAP) of the donor and recipient arteries was directly measured during the STA-MCA bypass procedure, and these data were statistically analyzed and evaluated.ResultsAmong 48 MMD patients, Suzuki grading revealed that 43.8% were in early stages (II and III), while 56.2% were in advanced stages (IV, V, and VI). Predominantly, 77.1% presented with ischemic-type MMD and 22.9% with hemorrhagic type. Pre-bypass assessments showed that 62.5% exhibited antegrade blood flow direction, and 37.5% had retrograde. The mean recipient artery pressure was 35.0 ± 2.3 mmHg, with a mean donor-recipient pressure gradient (δP) of 46.4 ± 2.5 mmHg between donor and recipient arteries. Post-bypass, mean recipient artery pressure increased to 73.3 ± 1.6 mmHg. No significant correlation (r = 0.18, P = 0.21) was noted between δP and Suzuki staging.ConclusionOur study elucidated that cerebral blood pressure significantly decreases beyond the moyamoya network at the distal M4 segment. Furthermore, we observed bidirectional flow in MCA territories and a significant positive pressure gradient between the STA and M4 segments. The lack of correlation between Suzuki stages and M4 pressures indicates that angiographic severity may not reflect hemodynamic conditions before surgery, highlighting the need for customized surgical approaches.

Intraoperative evaluation of local cerebral hemodynamic change by laser speckle contrast imaging for predicting postoperative cerebral hyperperfusion during STA-MCA bypass in adult patients with moyamoya disease.

Cerebral hyperperfusion (CHP) occurred frequently after direct superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery for moyamoya disease (MMD). We analyzed cortical microvascular density (CMD) and the change of cerebral blood flow (LΔCBF) using intraoperative laser speckle contrast imaging (LSCI) on 130 hemispheres of 95 consecutive adult patients with MMD. The demographic characteristics, cortical hemodynamic sources, bypass methods, intraoperative blood flow data, and relative CBF changes on single-photon emission computed tomography (SPECT) examination (SΔrCBF) were compared between the groups with and without CHP. The median values for CMD, LΔCBF, and SΔrCBF were significantly higher in the CHP group than in the non-CHP group (CMD 0.240 vs 0.206, P = 0.004; LΔCBF 2.285 vs 1.870, P < 0.001; SΔCBF 1.535 vs 1.260, P < 0.001). Multivariate analysis revealed that hemodynamic sources of recipient parasylvian cortical arteries from MCA (M-PSCAs), end-to-side (E-S) bypass method, CMD ≥ 0.217, and LΔCBF ≥ 1.985 were the risk factors for CHP. Intraoperative LSCI was useful for evaluating hemodynamics and predicting CHP in patients with MMD.

Risk Factors for Cerebral Hyperperfusion Syndrome After Combined Revascularization in Adult Patients with Moyamoya Disease.

Cerebral hyperperfusion syndrome (CHS) is known as a complication after bypass surgery for Moyamoya disease (MMD). However, the incidence of CHS has not been accurately reported, and there is no consensus on the risk factors associated with it. The aim of this study was to determine the risk factors associated with postoperative CHS after surgical combined revascularization used to treat adult patients with MMD. To assess the frequency and characteristics of CHS in patients with MMD after revascularization operations. Patients who received combined revascularization from Jan 2021 to Nov 2022 were retrospectively reviewed. Preoperative clinical characteristics and radiographic features were recorded. Postoperative CHS after surgery were examined. Multivariate logistic regression analyses were performed to identify the risk factors for CHS. A total of 133 patients (141 hemispheres) were included in this study. Postoperative CHS were observed in 28 hemispheres (19.8%), including focal cerebral hyperperfusion syndrome (FCHS) in 20 hemispheres (14.2%), hemorrhage in 4 (4.4%) hemispheres, seizures in 4 (4.4%) hemispheres. The results of multivariate logistic regression analysis indicated that preoperative hypertension (OR 3.940, 95% CI 1.275 ~ 12.180, p = 0.017), cerebral hemorrhage onset (OR 5.489, 95% CI 1.443 ~ 20.884, p = 0.013) and higher Hct level (OR 1.166, 95% CI 1.047 ~ 1.298, p = 0.005) were significantly associated with CHS after combined revascularization. Preoperative hypertension, cerebral hemorrhage onset, and higher Hct level were independent risk factors for CHS after combined revascularization.

Aneurysm appearing at the anastomosis site 11 years after superficial temporal artery–middle cerebral artery bypass surgery: moyamoya disease with a rapidly growing aneurysm. Illustrative case

BACKGROUND Superficial temporal artery–middle cerebral artery (STA-MCA) bypass surgery is performed to prevent ischemia and hemorrhage in patients with moyamoya disease. Only a few reports have described aneurysms appearing around the anastomosis site after bypass surgery, and the underlying mechanism remains unknown. OBSERVATIONS The present case involved a 62-year-old woman who underwent STA-MCA bypass surgery for ischemic quasi-moyamoya disease at 46 years of age. Postoperatively, she underwent annual magnetic resonance imaging examinations. At 11 years after STA-MCA bypass surgery, a 3-mm aneurysm appeared at the anastomosis site. Four years later, headache developed and the aneurysm had grown to 5 mm. Craniotomy clipping was performed to prevent rupture. The patient was discharged home 2 weeks after surgery without any apparent complications. LESSONS Long-term observation is crucial after direct bypass surgery for moyamoya disease. Measures to prevent rupture should be considered for cases involving aneurysm complications.

Flow volume mismatch dramatically affects transient neurologic symptoms after direct bypass in Moyamoya disease.

Transient neurological events (TNEs) occur after bypass surgery in Moyamoya disease (MMD); however, their pathology remains unknown. To elucidate the pathophysiology of TNEs, we investigated their relationship with perioperative superficial temporal artery (STA) blood flow volume, which was evaluated using ultrasonography. Forty-nine patients with MMD, who underwent direct bypass surgery, were included and stratified into TNE and non-TNE groups, respectively. The STA blood flow volume was evaluated at four time points (preoperatively and 2-4, 7, and 10-14days postoperatively), and a change in volume during the postoperative period was defined as a flow volume mismatch. We investigated the association between ultrasonographic findings of flow volume mismatch and TNEs and magnetic resonance imaging findings, such as the cortical hyperintensity belt (CHB) sign, using univariate and path analyses. The STA blood flow volume increased immediately postoperatively, gradually decreasing over time, in both groups. The TNE group showed a significant increase in blood flow volume 2-4days postoperatively (P = 0.042). Flow volume mismatch was significantly larger in the TNE group than in the non-TNE group (P = 0.020). In the path analysis, STA flow volume mismatch showed a positive association with the CHB sign (P = 0.023) and TNEs (P = 0.000). Additionally, the CHB sign partially mediated the association between STA flow volume mismatch and TNEs. These results suggest that significantly high STA blood flow volume changes occurring during the acute postoperative period after direct bypass surgery in MMD are correlated with TNEs and the CHB sign, suggesting involvement in the pathophysiology of TNEs.

Effect of newly developed scissors-attached micro-forceps on the recipient clamp time and occurrence of anastomotic site infarction after bypass surgery for moyamoya disease.

This study aimed to examine the effect of newly developed scissors-attached micro-forceps in superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis for moyamoya disease (MMD). Of 179 consecutive STA-MCA anastomoses on 95 hemispheres of 71 MMD patients at the University of Fukui Hospital between 2009 and 2023, 49 anastomoses on 26 hemispheres of 21 patients were enrolled in this retrospective cohort clinical trial intraoperative indocyanine green video-angiography did not demonstrate bypass patency in three anastomoses in two patients who were excluded. Twenty-one anastomosis in 19 hemispheres of 16 patients were performed using the conventional micro-forceps (conventional group, CG), and 25 anastomoses in 22 hemispheres of 19 patients were performed using scissors-attached micro-forceps (scissors group, SG). A small infarction near the anastomotic site detected using postoperative diffusion-weighted imaging was defined as anastomotic site infarction (ASI). Factors affecting the occurrence of ASI were examined by univariate, logistic regression, and receiver operating curve (ROC) analysis. There were no significant differences in clinical parameters such as age, sex, number of sacrificed branches, number of sacrificed large branches, and number of sutures between the CG and SG. However, the clamp time and occurrence of ASI were significantly lower in the SG than in the CG. Logistic regression analysis revealed that the clamp time was the only significant factor predicting the occurrence of ASI. A receiver operating curve analysis also revealed that the clamp time significantly predicted the occurrence of ASI (area under the curve, 0.875; cutoff value, 33.2 min). The newly developed scissors-attached micro-forceps could significantly reduce the clamp time and occurrence of ASI in STA-MCA anastomosis for MMD.

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

ObjectiveDirect 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. MethodsWe 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. ResultsAll 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. ConclusionsA 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.

Superior Visualization of Neovascularization with Silent Magnetic Resonance Angiography Compared to Time-of-Flight Magnetic Resonance Angiography After Bypass Surgery in Moyamoya Disease

The evaluation of postsurgical neoangiogenesis in patients with moyamoya disease (MMD) is crucial for appropriate patient management. This study aimed to assess the visualization of neovascularization after bypass surgery using noncontrast-enhanced silent magnetic resonance angiography (MRA) with ultrashort echo time and arterial spin labeling. After bypass surgery, 13 patients with MMD were followed up for >6months between September 2019 and November 2022. They underwent silent MRA in the same session as time-of-flight magnetic resonance angiography (TOF-MRA) and digital subtraction angiography (DSA). Two observers independently rated the visualization of neovascularization in both types of MRA from 1 (not visible) to 4 (nearly equal to DSA), with reference to DSA images as the standard. The mean scores were significantly higher for silent MRA compared with TOF-MRA (3.81±0.48 and 1.92±0.70, respectively) (P<0.01). The intermodality agreements were 0.83 and 0.71 for silent MRA and TOF-MRA, respectively. TOF-MRA depicted the donor artery and recipient cortical artery after direct bypass surgery, although fine neovascularization developed after indirect bypass surgery was poorly visualized. Silent MRA could reveal the developed bypass flow signal and perfused middle cerebral artery territory, which was almost equal to the DSA images. Silent MRA achieves better visualization of postsurgical revascularization in patients with MMD than TOF-MRA. Moreover, it may have the potential to provide visualization of the developed bypass flow equivalent to DSA.

How I do it: combined bypass for adult moyamoya disease with maximal consideration of cosmetic aspects.

Combined bypass, including direct and indirect procedures, has been recognized as the maximal revascularization to prevent further hemorrhagic or ischemic stroke in adult moyamoya disease (MMD). It is also important to consider cosmetic aspects when planning combined bypass for MMD. However, there are few reports that have described the cosmetic considerations in bypass surgery for MMD. We demonstrate our surgical techniques aimed at achieving extended revascularization as well as excellent cosmetic outcomes with figures and video. Our combined bypass procedures which focus on achieving maximal cosmetic results are effective methods that require no special instruments or techniques.

Real-Time Evaluation of Cerebral Autoregulation Based on Near-Infrared Spectroscopy to Predict Clinical Outcome after Bypass Surgery in Moyamoya Disease.

Impaired cerebral autoregulation (CA) can cause negative outcomes in neurological conditions. Real-time CA monitoring can predict and thereby help prevent postoperative complications for neurosurgery patients, especially those suffering from moyamoya disease (MMD). We applied the concept of moving average to the correlation between mean arterial blood pressure (MBP) and cerebral oxygen saturation (SCO2) to monitor CA in real time, revealing optimal window size for the moving average. The experiment was conducted with 68 surgical vital-sign records containing MBP and SCO2. To evaluate CA, the cerebral oximetry index (COx) and coherence obtained from transfer function analysis (TFA) were calculated and compared between patients with postoperative infarction and those who without. For real-time monitoring, the moving average was applied to COx and coherence to determine the differences between groups, and the optimal moving-average window size was identified. The average COx and coherence within the very-low-frequency (VLF) range (0.02-0.07 Hz) during the entire surgery were significantly different between the groups (COx: AUROC = 0.78, p = 0.003; coherence: AUROC = 0.69, p = 0.029). For the case of real-time monitoring, COx showed a reasonable performance (AUROC > 0.74) with moving-average window sizes larger than 30 minutes. Coherence showed an AUROC > 0.7 for time windows of up to 60 minutes; however, for windows larger than this threshold, the performance became unstable. With an appropriate window size, COx showed stable performance as a predictor of postoperative infarction in MMD patients.

Bypass Surgery for Moyamoya Disease, Part 1: Special Considerations and Techniques

In this review article, the author describes the eligible patients, concept, surgical technique, and long-term outcome of the superficial temporal artery to middle cerebral artery(STA-MCA)anastomosis and the ultimate indirect bypass, called encephalo-duro-myo-arterio-pericranial synangiosis(EDMAPS)for adult moyamoya disease, in addition to the novel diagnostic criteria. The procedure dramatically improves or normalizes the cerebral blood flow immediately after surgery and thus contributes to preventing ischemic complications during and after surgery. However, the arterial wall of these patients is extremely thin and fragile; therefore, the surgeons should be trained extensively and have absolute confidence in their ability to perform this procedure. The surgeons should be aware that STA-MCA anastomosis frequently induces the hyper-perfusion phenomenon in adult patients with moyamoya due to prolonged cerebral ischemia. The extent of craniotomy determines the amount of surgical collaterals after indirect surgery; thus, a wide craniotomy including most of the frontal area, especially the medial frontal area, is critical to improve the postoperative prognosis. This procedure can markedly diminish the dangerous periventricular collateral channels and provides excellent long-term outcomes for up to 20 years after surgery. Long-term follow-ups longer than 20 years are important to monitor the patients with this unique and peculiar disease.

Strategic tunnelling of superficial temporal artery during bypass surgery for moyamoya disease.

The superficial temporal artery to middle cerebral artery bypass remains the favoured direct technique of cerebral revascularization in moyamoya angiopathy. We describe a novel technique of tunnelling the superficial temporal artery through the temporalis muscle. The temporalis muscle is raised as a flap off the temporal bone. A triangular window is created on the temporalis fascia, and a tunnel is created for the superficial temporal artery to pass through the muscle belly. This innovative technique allows passage of the superficial temporal artery to the brain without kink or compression ensuring good bypass function and improves long-term patency.

Application of FLOW 800 in extracranial-to-intracranial bypass surgery for moyamoya disease.

The surgical treatment of moyamoya disease is heavily reliant upon a real-time understanding of cerebral hemodynamics. The application of FLOW 800 allows the surgeon to semiquantify the degree of perfusion to the cerebral cortex following extracranial-to-intracranial (EC-IC) bypass surgery. The authors present three illustrative cases demonstrating common intraoperative findings prior to and following anastomosis using FLOW 800. All patients were diagnosed by catheter angiogram with moyamoya disease and noninvasive imaging demonstrating hemispheric hypoperfusion. Superficial temporal artery (STA)–to–middle cerebral artery (MCA or M4) bypasses were performed to augment intracranial perfusion. The patients tolerated the procedures well and were discharged without event in stable neurological condition.The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21191

Five-Day Bed Rest Reduces Postoperative Intracerebral Hemorrhage After Direct Bypass for Moyamoya Disease

Postoperative intracerebral hemorrhage (ICH) after direct bypass surgery for Moyamoya disease could contribute to neurologic deterioration. The aim of this study was to evaluate the effectiveness of 5-day bed rest in reducing the occurrence of postoperative ICH. This study included 122 consecutive hemispheres in 87 Japanese adult MMD patients, composed of 80 control hemispheres from historical data and 42 hemispheres after 5-day bed rest. They all underwent direct bypass surgery. The incidence of postoperative ICH and neurologic deterioration assessed via the modified Rankin Scale were investigated and statistically analyzed. Postoperative ICH was observed in 9 out of the 80 (11.3%) control patients, but not in the 42 patients with 5-day bed rest. The incidence of postoperative ICH and neurologic deterioration via the modified Rankin Scale were significantly different between the 2 groups (P= 0.0268 and 0.0078, respectively). Univariate logistic analysis revealed that 5-day bed rest significantly reduced the incidence of postoperative ICH (P= 0.0048). Five-day bed rest after direct bypass surgery dramatically can reduce the incidence of postoperative ICH and neurologic deterioration after direct bypass surgery.

Risk factors for postoperative ischemic complications in pediatric moyamoya disease

BackgroundIschemic events are the most common postoperative complication in bypass surgery for moyamoya disease (MMD), but the risk factors for pediatric MMD remain unclear. The goal of the study was to investigate the risk factors for postoperative ischemic complications in pediatric MMD patients.MethodsWe retrospectively reviewed a consecutive series of pediatric MMD cases at Beijing Tiantan Hospital, Capital Medical University from June 2010 through June 2019. Preoperative clinical variables and radiographic findings were recorded, and logistic regression analysis was carried out to identify the risk factors for postoperative ischemic events.ResultsA total of 533 operations in 336 patients were included in this study. Postoperative complications occurred after 51 operations (9.6%), including 40/447 indirect bypass procedures, 9/70 direct bypass procedures, and 2/16 combined bypass procedures. Postoperative ischemic events were the most common complication and occurred in 30 patients after 31 procedures (8.9% per patient; 5.8% per operation), including 26/447 indirect bypass procedures, 4/70 direct bypass procedures, and 1/16 combined bypass procedures, and the incidence of these events did not differ significantly between indirect and non-indirect bypass (5.8% vs 5.8%; p = 0.999). Multivariate logistic regression analyses revealed that older age at operation (OR 1.129, 95% CI 1.011–1.260, p = 0.032) and posterior cerebral artery involvement (OR 2.587, 95% CI 1.030–6.496, p = 0.043) were significantly associated with postoperative ischemic events.ConclusionWe speculate that older age at operation and posterior cerebral artery involvement are risk factors for postoperative ischemic events in pediatric MMD patients.

Retinal Vasculature Changes after Bypass Surgery for Moyamoya Disease

A 48-year-old woman with slurred speech was diagnosed with Moyamoya disease. Digital subtraction angiography disclosed left ophthalmic artery originating from the internal carotid artery (Fig A, arrow), and supplied by orbital branches of the middle meningeal and facial artery (Fig A, arrowhead). Preoperative examinations showed normal superficial vascular complex (SVC) in the left eye (OS) on OCT angiography (Fig B). She underwent left extracranial-intracranial bypass from the superficial temporal artery to the middle cerebral artery.

Evaluation of Hemodynamic Change by Indocyanine Green-FLOW 800 Videoangiography Mapping: Prediction of Hyperperfusion Syndrome in Patients with Moyamoya Disease.

Objective Hyperperfusion syndrome (HPS) after bypass surgery for moyamoya disease (MMD) mainly results from redistribution of blood flow, which leads to poor outcomes, while effective methods to predict HPS are still lacking. Indocyanine green (ICG) videoangiography can assess regional cerebral blood flow changes semiquantitatively with the application of FLOW 800 software. The purpose of this study was to investigate whether the intraoperative evaluation of local hemodynamic changes around anastomotic sites using FLOW 800 videoangiography mapping can predict the incidence of HPS and clinical outcomes. Methods Of the patients who were diagnosed with MMD in our hospital between August 2018 and December 2019, who underwent superficial temporal artery-middle cerebral artery bypass surgeries, we investigated 65 hemispheres (in 62 patients) in which intraoperative ICG analysis was performed using FLOW 800 (Zeiss Meditec, Oberkochen, Germany) to evaluate the local cerebral hemodynamics before and after anastomosis. Regions of interest were set at more than 2 points on the brain surface according to the location and situation of recipient arteries in the surgical area. Peak cerebral blood volume (CBV), regional cerebral blood flow (CBF), and time to peak (TTP) were calculated from the selected points. As the data were available intraoperatively, anastomoses were performed in a suitable area. According to the occurrence of HPS, patients were divided into the asymptomatic and symptomatic groups, from which hemodynamic parameters were compared. Furthermore, ROC analysis was performed to determine the diagnostic accuracy of change rates in CBV, CBF, and TTP (i.e., ΔCBV, ΔCBF, and ΔTTP) for predicting HPS. Results Data from the 62 patients were analyzed, and all patients were closely assessed during hospitalization after the procedures. The values of ΔCBV and ΔCBF were significantly higher in the symptomatic group (p < 0.01), while ΔTTP is slightly lower in the symptomatic group with no statistical differences (p = 0.72). Hemodynamic parameters including ΔCBV and ΔCBF, calculated by FLOW 800, had high sensitivity and specificity according to the ROC curve (ΔCBV: AUC = 0.743, 95% CI, 0.605–0.881, p = 0.002; ΔCBF: AUC = 0.852, 95% CI, 0.750–0.954, p < 0.01), which could be used as predictors for HPS. Conclusions Intraoperative ICG-FLOW 800 videoangiography mapping is a safe method which can reflect hemodynamic characteristics in the surgical area for MMD, the findings of which correlate with the occurrence of HPS. Parameters including ΔCBV and ΔCBF are proven to be efficient in the prediction of HPS.

Hemodynamic study about cortical hyperintensity belt sign after direct bypass surgery for moyamoya disease

Transient neurological events (TNEs) are observed after direct bypass surgery in patients with moyamoya disease (MMD). Although a correlation between cortical hyperintensity belt signs (CHBs) and TNEs has been reported, the pathophysiology of CHBs is still unknown. The purpose of this study was to reveal the pathophysiology of CHBs by using dynamic susceptibility contrast-magnetic resonance imaging. Thirty patients with MMD were included in this study. We provided scores (0–2) for the existence of CHBs on postoperative FLAIR images. We placed the ROI for the presented area of CHBs in the images of cerebral blood flow, CBV, and MTT. We calculated the change of the hemodynamic parameters (increase ratio, IR) and analyzed the relationship between IRs, CHB scores, and TNEs. TNEs were observed in 15 cases (50%) and CHBs were detected in 28 cases (93%). TNEs showed significantly higher CHB scores than those without (p < 0.05). The group of CHB score 2 showed a significantly higher CBV IR than the group with of score 0 (p < 0.05). Patients with TNEs showed a significantly higher CBV IR than those without (p < 0.05). As for the cut-off level to predict an appearance of TNEs, the CBV IR was 1.36 by the Receiver Operating Characteristic analysis, and the sensitivity and specificity were 80% respectively. We hypothesize that the pathophysiology of the CHBs are vasogenic edemas because the postoperative CBV increase correlated with the CHBs.