Ultrasonographic Changes after Indirect Revascularization Surgery in Pediatric Patients with Moyamoya Disease

Ultrasonographic Predictors for Post-operative Ischemic Events After Indirect Revascularization Surgeries in Patients with Moyamoya Disease

OBJECTIVE

Recurrent stroke after revascularization surgeries predicts poor outcome in patients with moyamoya disease (MMD). Early identification of patients with stroke risk paves the way for rescue intervention. This study aimed to investigate the role of ultrasound in identifying patients at risk of post-operative ischemic events (PIEs).

METHODS

This prospective study enrolled patients with symptomatic MMD who underwent indirect revascularization surgeries. Ultrasound examinations were performed preoperatively and at 3 mo post-operatively to evaluate the hemodynamic changes in extracranial and intracranial arteries on the operated side. PIE was defined as ischemic stroke or transient ischemic attack in the operated hemisphere within 1 y. The areas under receiver operating characteristic curves were compared between models for prediction of PIE.

RESULTS

A total of 56 operated hemispheres from 36 patients (mean age, 23.0 ± 18.5 y) were enrolled in this study, and 27% developed PIE. In multivariate logistic regression models, PIE was associated with lower end-diastolic velocity and flow volume (FV) of the ipsilateral external carotid artery (ECA), and lower FV of ipsilateral superficial temporal artery and occipital artery at 3 mo post-operatively (all p < 0.05). Moreover, the post-operative FV of the ipsilateral ECA was the only one factor that significantly increased the areas under receiver operating characteristic curves from 0.727 to 0.932 when adding to a clinical-angiographic model for prediction of PIE (p = 0.017). This parameter was significantly lower in hemispheres with PIE, both in adult and pediatric patients.

CONCLUSION

After indirect revascularization, surgeries in patients with symptomatic MMD, FV of ipsilateral ECA at 3 mo helps clinicians to identify patients at risk of PIE.

Ultrasound parameters associated with stroke in patients with moyamoya disease: a logistic regression analysis

Background

Moyamoya disease can lead to stroke with devastating consequences, it is necessary to find a non-invasive and effective approach to identify the occurrence of stroke. In this study, we aim to analyze the association between ultrasound parameters and ipsilateral cerebral hemisphere stroke in patients with moyamoya disease by logistic regression analysis.

Methods

In this retrospective case–control study, 88 patients with MMD (153 cerebral hemispheres) hospitalized in Beijing Tiantan Hospital, Capital Medical University from November 2020 to October 2021 were analyzed. According to the occurrence of stroke, the 153 cerebral hemispheres were divided into a stroke group and a non-stroke group. Clinical data and ultrasound parameters of the ipsilateral internal carotid artery, superficial temporal artery, maxillary artery, and posterior cerebral artery were recorded. The ultrasound parameters were divided into four groups according to interquartile range, and then they were compared between the stroke group and the non-stroke group. Those with significant differences were scored by multivariate logistic regression analysis.

Results

There were 75 cerebral hemispheres (49.0%) in the stroke group and 78 cerebral hemispheres (51.0%) in the non-stroke group. Logistic regression analysis showed that the internal diameter of the internal carotid artery, peak systolic velocity of the internal carotid artery and peak systolic velocity of the posterior cerebral artery were independently correlated factors for stroke in patients with MMD. The fourth quartile group of the above three ultrasound parameters was taken as the reference group, and the odds ratio of the first quartile group were 11.679 (95% CI 2.918–46.749, P = 0.001), 19.594 (95% CI 4.973–77.193, P < 0.001), and 11.657 (95% CI 3.221–42.186, P < 0.001), respectively.

Conclusion

Ultrasound parameters are independently correlated with ipsilateral cerebral stroke in patients with MMD. Ultrasound provides a new way to identify stroke in MMD patients. Future prospective cohort studies are needed to verify the clinical value of ultrasound in identifying patients with MMD at high risk of stroke.

Imaging methods for surgical revascularization in patients with moyamoya disease: an updated review

Neuroimaging is crucial in moyamoya disease (MMD) for neurosurgeons, during pre-surgical planning and intraoperative navigation not only to maximize the success rate of surgery, but also to minimize postsurgical neurological deficits in patients. This is a review of recent literatures which updates the clinical use of imaging methods in the morphological and hemodynamic assessment of surgical revascularization in patients with MMD. We aimed to assist surgeons in assessing the status of moyamoya vessels, selecting bypass arteries, and monitoring postoperative cerebral perfusion through the latest imaging technology.

Clinical Significance of Ultrasound-Based Hemodynamic Assessment of Extracranial Internal Carotid Artery and Posterior Cerebral Artery in Symptomatic and Angiographic Evolution of Moyamoya Disease: A Preliminary Study

Objective: To investigate the hemodynamic changes using ultrasound according to digital subtraction angiography (DSA) findings and explore the association between ultrasound parameters and clinical symptoms of moyamoya disease (MMD). Methods: Hemodynamic parameters of extracranial internal carotid artery (EICA) and posterior cerebral artery (PCA) were evaluated by ultrasound. According to DSA findings, EICA parameters among Suzuki stages (stage I-II, III-IV, and V-VI), and PCA parameters among leptomeningeal system scores (score 0-2, 3-4, and 5-6) were compared, respectively. ROC analysis was performed based on the ultrasound parameters to distinguish stroke from non-stroke patients. Results: Forty patients with MMD were included in our study (16 men; median age, 37 years). The diameter (D), peak systolic velocity (PSV), end diastolic velocity (EDV) and flow volume (FV) of EICA decreased as the Suzuki stage advanced (D: P < 0.001; PSV: P < 0.001; EDV: P < 0.001; FV: P < 0.001). The PSV and EDV of PCA increased as the leptomeningeal system scores advanced (PSV: P < 0.001; EDV: P < 0.001). ROC analysis showed that the area under the curves (AUCs) based on the D and FV of EICA, the PSV and EDV of PCA and their combination were 0.688, 0.670, 0.727, 0.684, and 0.772, respectively, to distinguish stroke from non-stroke patients. Conclusions: Ultrasound parameters were related to Suzuki stages and leptomeningeal system scores. Ultrasound may be useful in predicting the occurrence of stroke in patients with MMD. Future prospective studies with large sample sizes and long-term follow-up are needed to confirm our preliminary findings.

Carotid ultrasonography predicts collateral development following combined direct and indirect revascularization surgery in adult ischemic Moyamoya disease

OBJECTIVE

The relationship between carotid ultrasonographic parameters and postoperative collateral development in adult ischemic moyamoya disease (MMD) patients who received combined direct and indirect revascularization surgery remains unclear. Herein, we investigated the postoperative changes in carotid ultrasonographic parameters in patients with adult ischemic MMD.

METHODS

We studied 28 adult ischemic MMD patients (31 hemispheres) who underwent combined revascularization surgery. Patients underwent preoperative and postoperative (within 14 days and 3, 12, and 24 months after surgery) magnetic resonance imaging and carotid ultrasonography. We defined the hemisphere in which all signal intensities of the superficial temporal, middle meningeal, and deep temporal arteries were increased compared with that before surgery on magnetic resonance angiography as well-developed collateral establishment.

RESULTS

Patients with good collateral establishment on MRA at 2-year after surgery had a lower external carotid artery (ECA) pulsatility index (PI) (P = 0.0413) and ECA/internal carotid artery (ICA) pulsatility index (PI) ratio (P = 0.0427) at 3-month post-operation. At 3-month post-operation, a cut-off ECA PI of 1.416 (sensitivity 40.0 %, specificity 92.3 %, area under the curve 0.7282, likelihood ratio 5.20, P = 0.0404) and ECA/ICA PI ratio of 0.8768 (sensitivity 50.0 %, specificity 92.31 %, area under the curve 0.7308, likelihood ratio 6.50, P = 0.0415) provided reliable values for good prediction of collateral development at 2 years after revascularization.

CONCLUSION

ECA/ICA PI ratio and ECA PI at 3-month after surgery can be one of the indicators for predicting future well-developed neovascularization on MRA and better outcome in patients with adult ischemic MMD who received combined direct and indirect revascularization surgery.

Association Between Ultrasound Parameters and History of Ischemic or Hemorrhagic Stroke in Patients With Moyamoya Disease

Objective: To explore the association between ultrasound parameters and previous ischemic or hemorrhagic stroke in patients with moyamoya disease (MMD), and develop an ultrasound-based nomogram to identify stroke in patients with MMD.

Methods: We prospectively enrolled 52 consecutive patients (92 hemispheres) with MMD at the Beijing Tiantan Hospital. Thirty-six patients (65 hemispheres) were assigned to the training dataset from September 2019 to February 2020, and 16 patients (27 hemispheres) were assigned to the validation dataset from March 2020 to July 2020. Multivariate logistic regression analysis was applied to identify ultrasound parameters associated with previous history of ipsilateral stroke in patients with MMD, and a nomogram was subsequently constructed to identify stroke in patients with MMD. The performance of the nomogram was evaluated with respect to discrimination, calibration, and clinical usefulness.

Results: Multivariate analysis indicated that the flow volume (FV) of the extracranial internal carotid artery (EICA) and the peak systolic velocity (PSV) of the posterior cerebral artery (PCA) were independently associated with ipsilateral stroke in patients with MMD, a nomogram incorporating these two parameters was constructed to identify stroke patients. The area under the receiver operating characteristic (AUROC) curves was 0.776 (95% CI, 0.656–0.870) in the training dataset and 0.753 (95% CI, 0.550–0.897) in the validation dataset suggested that the model had good discrimination ability. The calibration plot showed good agreement in both the two datasets. The decision curve analysis (DCA) revealed that the nomogram was clinically useful.

Conclusions: Ultrasound parameters of EICA and PCA are independently associated with history of previous ipsilateral ischemic or hemorrhagic stroke in patients with MMD. The present ultrasound-based nomogram might provide information to identify MMD patients with high risk of stroke. Future long-term follow-up studies are needed to prove the predictive value in other independent cohorts.

Clinical Trial Registration:http://www.chictr.org.cn/index.aspx. Unique Identifier: ChiCTR1900026075.

Choroid plexus perfusion and intracranial cerebrospinal fluid changes after angiogenesis

Recent studies have provided evidence that cortical brain ischemia may influence choroid plexus function, and such communication may be mediated by either traditional CSF circulation pathways and/or a possible glymphatic pathway. Here we investigated the hypothesis that improvements in arterial health following neoangiogenesis alter (i) intracranial CSF volume and (ii) choroid plexus perfusion in humans. CSF and tissue volume measurements were obtained from T₁-weighted MRI, and cortical and choroid plexus perfusion were obtained from perfusion-weighted arterial spin labeling MRI, in patients with non-atherosclerotic intracranial stenosis (e.g. Moyamoya). Measurements were repeated after indirect surgical revascularization, which elicits cortical neoangiogenesis near the revascularization site (n = 23; age = 41.8 ± 13.4 years), or in a cohort of participants at two time points without interval surgeries (n = 10; age = 41.7 ± 10.7 years). Regression analyses were used to evaluate dependence of perfusion and volume on state (time 1 vs. 2). Post-surgery, neither CSF nor tissue volumes changed significantly. In surgical patients, cortical perfusion increased and choroid plexus perfusion decreased after surgery; in participants without surgeries, cortical perfusion reduced and choroid plexus perfusion increased between time points. Findings are discussed in the context of a homeostatic mechanism, whereby arterial health, paravascular flow, and/or ischemia can affect choroid plexus perfusion.

Postoperative change of neuropsychological function after indirect revascularization in childhood moyamoya disease: a correlation with cerebral perfusion study

PURPOSE

The relationships between postoperative functional improvement in various cognitive domains and regional hemodynamic change have not been sufficiently studied in childhood moyamoya disease (MMD). The present study aimed to examine the cognitive benefit of indirect revascularization, the underlying biological mechanism, and factors affecting surgical outcome in childhood MMD.

METHODS

Twenty-three patients with MMD aged under 20 years received neuropsychological examinations before and after indirect revascularization surgery, evaluating intellectual function, verbal and visual memory, and executive function. Among them, 13 patients had magnetic resonance perfusion (MRP) studies, in which regional cerebral perfusion was rated.

RESULTS

Postoperative improvement was observed in verbal memory performances (p = 0.02-0.03) and in cerebral perfusion at all 26 cerebral hemispheres (p = 0.003-0.005), especially in the middle cerebral artery (MCA) territories (p = 0.001-0.003). Hemodynamic improvement in the left MCA territories was significantly correlated with improvement of both verbal new learning (p = 0.01) and intellectual function (p = 0.004). Postoperative cognitive improvement of immediate recall and verbal intellectual function was associated with female sex (r = - 0.42) and symptom duration (p = - 0.03), respectively. Hemodynamic improvement in the MCA territories was related to longer follow-up intervals (p = 0.02).

CONCLUSION

The findings revealed that the selective postoperative cognitive improvement was associated with increased regional perfusion in the MCA territories, and indicate the importance of early intervention and the potential of indirect revascularization regarding long-term outcome.

Changing Ischemic Lesion Patterns and Hemodynamics of the Posterior Cerebral Artery in Moyamoya Disease

OBJECTIVE

The aim of this study was to determine how hemodynamics of the posterior cerebral artery (PCA) are associated with cerebral ischemic lesions in moyamoya disease (MMD).

METHODS

Thirty-six patients with ischemic MMD (Suzuki grade IV-V) were retrospectively analyzed. Hemodynamic parameters of the PCA were measured by transcranial color-coded sonography. We classified the range of ischemic lesions into 3 grades and perfusion levels into 3 grades according to computed tomography (CT) results. PCA steno-occlusion and leptomeningeal collaterals were confirmed by digital subtraction angiography. Ultrasonographic parameters in the PCA were compared with these radiographic findings.

RESULTS

The velocity in the involved PCA (mean flow velocity [MFV] median, 42.00 [range, 34.50-58.00] cm/s) was significantly lower than that in the normal PCA (MFV median, 95.00 [range, 76.50-119.50] cm/s) (P < .001). The velocity in the PCA increased significantly as the leptomeningeal collateral stage advanced (MFV stage 1: median, 38.50 [range, 29.75-63.50] cm/s; stage 2: median, 55.00 [range, 44.00-96.00] cm/s; stage 3: median, 94.00 [range, 54.00-118.25] cm/s; stage 4: median, 85.50 [range, 70.50-117.75] cm/s, respectively) (P < .05). Decreased PCA velocities were associated with a larger ischemic area on CT (P ≤ .001). PCA velocity had no correlation with CT perfusion level of the temporal and frontal lobes. PCA velocity had significant correlations with perfusion level in the occipital (P < .001) and parietal lobes (P < .05).

CONCLUSIONS

Our results suggest ischemic lesion patterns (as demonstrated on CT imaging) are associated with PCA velocity measurements in the advanced stage of MMD. Thus, monitoring PCA velocity in patients with advanced MMD may provide additional information to assist in managing these patients.

Improving Indirect Revascularization for Effective Treatment of Adult Moyamoya Disease: A Prospective Clinical, Cerebral Angiographic, and Perfusion Study

BACKGROUND

Indirect revascularization is simple and safe, but it is not commonly used in adult moyamoya disease owing to its unreliable effect. This prospective study aimed to evaluate the effectiveness of indirect revascularization in treating adult moyamoya disease after refinement of the surgical technique and perioperative care.

METHODS

Adult patients who underwent indirect revascularization as the primary treatment for moyamoya disease between November 2013 and January 2017 were studied. The indirect revascularization procedures included encephalo-duro-arterio-synangiosis and encephalo-myo-synangiosis in the temporal region and encephalo-pericranio-synangiosis in other hypoperfusion areas. The preoperative and postoperative clinical conditions, cerebral angiography findings, and time-to-peak prolongation areas on magnetic resonance perfusion studies were assessed to evaluate the revascularization effect. Refinements of the surgical technique included the selection of surgical area based on perfusion imaging, craniotomy size, and number of affected hemispheres, along with the inclusion of a dural flap in every procedure.

RESULTS

Nineteen patients (17 females and 2 males), and a total of 31 cerebral hemispheres, were included. The mean patient age was 32.7 ± 11.4 years. After a mean follow-up of 38.6 ± 11.5 months, all patients showed clinical improvement or stabilization. Available postoperative angiography demonstrated Matsushima grade A or B in 19 of 21 hemispheres. The mean time-to-peak prolongation index of all 31 hemispheres improved from 24.09 ± 9.83% preoperatively to 12.82 ± 6.75% at 3-6 months after surgery (P < 0.001). The complication rate was 12.9%, and all complications were transient.

CONCLUSIONS

With refinements of surgical techniques and perioperative care, indirect revascularization is more reliable and can be a viable alternative treatment for adult moyamoya disease. In our cohort, outcomes were satisfactory, with mean 38.6-month follow-up.

[Methods to assess competence of indirect cerebral revascularization in children]

The use of catheterization cerebral angiography (CCA) to assess collateral blood flow through an indirect anastomosis is traumatic for children, uses a high radiation dose, and requires anesthetic care in most cases.

AIM

we aimed to compare the capabilities of triplex ultrasound (TU) of vessels, magnetic resonance angiography (MRA), computed tomography angiography (CTA), and CCA in assessing the competence of indirect cerebral revascularization (ICR) in children.

MATERIAL AND METHODS

ICR was performed in 18 children in 24 hemispheres (24 operations). The results were evaluated by Matsushima classification-based comparison of the data of preoperative and postoperative clinical examinations, TU of the superficial temporal artery, magnetic resonance imaging (MRI) and computed tomography (CT) of vessels, and selective cerebral angiography.

RESULTS

After surgery, improvements in the neurological and neuropsychological status were assessed. Matsushima grade A collaterals were found in 12 (50%) cases, grade B collaterals were present in 3 (13%) cases, grade C collaterals were present in 7 (29%) cases, and grade D collaterals were detected in 1 (4%) case; in 1 (4%) case, the superficial temporal artery was not enhanced. MR angiography visualized 18 (75%) indirect anastomoses, CT angiography revealed 4 indirect anastomoses, and TU visualized 4 indirect anastomoses. Comparison of preoperative and postoperative TU data for the superficial temporal artery revealed significant changes in blood flow in the form of increased rate indices and a decreased resistance index; mean values of indices for each angiographic class of revascularization and significant differences in pre- and postoperative observations were calculated.

CONCLUSION

Examination of ICR competence using CCA is necessary in the presence of persistent clinical signs of chronic cerebral circulatory insufficiency, absence of increased blood flow and decreased peripheral resistance in the superficial temporal artery, and lack of anastomosis according to MRA. The most optimal techniques for postoperative examination are MRA with perfusion and diffusion maps and TU.

Color Doppler ultrasonography as an alternative tool for postoperative evaluation of collaterals after indirect revascularization surgery in Moyamoya disease

The cerebral hypoperfusion caused by chronic progressive stenosis or occlusion of intracranial arteries in moyamoya disease can be treated by direct bypass or indirect revascularization procedures. The extent of collaterals from the external carotid artery (ECA) after indirect revascularization surgery is the key point of angiographic follow-up, and the invasiveness of angiography impelled us to investigate the role of ultrasonography in the evaluation of collaterals. We hypothesized that the collaterals shown on angiography might produce corresponding hemodynamic changes in color Doppler ultrasonography. We prospectively recruited moyamoya patients who underwent indirect revascularization surgery and received both preoperative and postoperative angiography and color Doppler ultrasound studies. The collaterals on angiography were graded according to Matsushima method. A total of 21 patients (age, 17 ± 10.2 years) with 24 operated hemispheres were enrolled. Patients who showed better collateral establishment by angiography had higher end-diastolic velocity (EDV), lower resistance index (RI), and larger flow volume in the superficial temporal artery (STA) and ECA (all p < 0.05). In STA, increase of EDV greater than 13.5 cm/sec or reduction of RI greater than 0.19 after operation corresponded to 94% of Matsushima grade A+B. In ECA, post-operative EDV greater than 22 cm/sec or increase of EDV greater than 6.4 cm/sec also corresponded to 94% of Matsushima grade A+B. Our findings revealed potential roles of color Doppler ultrasonography in identifying patients with poor collaterals after indirect revascularization procedures.

Chronologic Evaluation of Cerebral Hemodynamics by Dynamic Susceptibility Contrast Magnetic Resonance Imaging After Indirect Bypass Surgery for Moyamoya Disease

OBJECTIVE

Although indirect bypass surgery is an effective treatment option for patients with ischemic-onset moyamoya disease (MMD), the time point after surgery at which the patient's hemodynamic status starts to improve and the time point at which the improvement reaches a maximum have not been known. The objective of the present study is to evaluate the hemodynamic status time course after indirect bypass surgery for MMD, using dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI).

METHODS

We retrospectively analyzed the cases of 25 patients with MMD (37 sides; mean age, 14.7 years; range, 3-36 years) who underwent indirect bypass surgery and repeated DSC-MRI measurement within 6 months after the operation. The difference in the mean transit time (MTT) between the target regions and the control region (cerebellum) was termed the MTT delay, and we measured the MTT delay's chronologic changes after surgery.

RESULTS

The postoperative MTT delay was 1.81 ± 1.16 seconds within 1 week after surgery, 1.57 ± 1.01 at weeks 1-2, 1.55 ± 0.68 at weeks 2-4, 1.32 ± 0.68 at months 1-2, 0.95 ± 0.32 at months 2-3, and 0.77 ± 0.33 at months 3-6. Compared with the preoperative value (2.11 ± 0.98 seconds), the MTT delay decreased significantly from 2 to 4 weeks after surgery (P < 0.05).

CONCLUSIONS

The amelioration of cerebral hemodynamics by indirect bypass surgery began soon after surgery and gradually reached a maximum at 3 months after surgery. DSC-MRI detected small changes in hemodynamic improvement, which are suspected to be caused by the initiation of angiogenesis and arteriogenesis in the early postoperative period.

Enlarged Encephalo-Duro-Myo-Synangiosis Treatment for Moyamoya Disease in Young Children

OBJECTIVE

To retrospectively evaluate the midterm therapeutic effect of enlarged encephalo-duro-myo-synangiosis (EDMS) for moyamoya disease (MMD) in young children.

METHODS

Seventy-seven children diagnosed with MMD by digital subtraction angiography (DSA) or magnetic resonance angiography (MRA) were treated between January 2011 and December 2014 in our center. Their clinical features, imaging, and operative reports were analyzed.

RESULTS

Four patients presented with intracerebral hemorrhage, whereas 73 presented with ischemic symptoms. Revascularization procedures were performed unilaterally on 11 left hemispheres and 9 right hemispheres, and 57 had bilateral surgeries. The average length of surgery was 143 ± 24 minutes, with 28 ± 9 mL of blood loss. The mean period of follow-up was 28.43 ± 15.31 months. Cerebral blood flow increased 3 months after the operations in the previously affected regions. Collateralization from the deep temporal artery, superficial temporal artery, and the middle meningeal artery was found by DSA or MRA. In cases where single-photon emission computed tomography was obtained, it demonstrated better perfusion postoperatively. The ischemic symptoms were relieved in 118 (88.06%) hemispheres, and remained stable in 5 (3.73%) hemispheres. There were 12 radiographic cerebral infarctions (8.96%) within 1 month postoperatively.

CONCLUSIONS

Enlarged EDMS is safe and effective for MMD in young children. Extensive and multilayered revascularization could significantly preserve neurologic function. The long-term effect on posterior circulation disease development needs further investigation.