| Backgrounds and Purpose:Moyamoya disease(MMD)is a chronic cerebrovascular disorder characterized by progressive stenosis and/or occlusion of the intracranial internal carotid artery,which can cause TIA or cerebral infarction and other common clinical symptoms.The clinical symptoms of moyamoya disease are not only related to the degree of cerebral perfusion decline caused by vascular occlusion,but also affected by all kinds of collateral compensation.Previous studies have found significant differences in clinical characteristics between pediatric and adult moyamoya disease(MMD)patients,but few studies have focused on the reason underlying these differences.In this work,we aimed to investigate the differences in leptomenimgeal collateral(LMC)status between pediatric and adult MMD patients and to analyze the effects of LMCs on clinical characteristics and therapeutic prognosis.We set the normal people as control group,we used the arterial spin labeling(ASL)technique to evaluate cerebral perfusion level and leptomenimgeal collateral compensation in the MCA territories of the patients with moyamoya disease.We sought to provide a novel MMD grading system based on collateral circulation to evaluate symptoms and predict prognosis.Methods:1.We retrospectively analyzed 214 MMD patients from January 2014 to December 2016.Sex,initial symptoms,Suzuki stages and LMC status were compared between pediatric and adult patients.LMC status was graded as good or poor depending on the retrograde flow from the posterior cerebral artery(PCA)on digital subtraction angiography(DSA).2.Adults with ischemic moyamoya disease from April 2017 to October 2017 were enrolled.All MMD patients underwent DSA,MRI and ASL-MRI examinations to evaluate the leptomenimgeal compensation and CBF and CBV of MCA territories in symptomatic hemispheres.The CBF and CBV were also compared between ischemic moyamoya disease and 20 healthy adult volunteers.3.A collateral circulation grading system with scores ranging from 1-13 was established,as follows:In the Circle of Willis system,primary collateral flow via the fetal variant posterior communicating artery(PComA)or hyperplastic PComA was scored as I,otherwise,the score was 0;(2)The leptomenimgeal system includes the following 3 parts of collateral networks:(1)the parieto-occipital branch of the posterior cerebral artery(pPCA)anastomoses to the anterior cerebral artery territory:a score of 1 was assigned if the blood supply to the cortical border zone was between the ACA and PCA territory,and a score of 2 was assigned if the blood supply was over the Central Sulcus;(2)the anterior temporal branch of the PCA anastomoses to the temporal branch of the middle cerebral artery was assigned a score of I;(3)pPCA anastomoses to the MCA a score of 1 was assigned if the pPCA anastomoses to the M4 segment of the MCA,a score of 2 was assigned if the pPCA anastomoses to the M3 segment,and a score of 3 was assigned if the pPCA anastomoses to the M2 or Ml segment.The leptomeningeal system scores were the sum of the three parts above,and the absence of leptomeningeal anastomoses was assigned a score of 0.Perforator collateral flow was scored as 6 to 1,which corresponded to Suzuki stages 1 to 6.Dynamic susceptibility contrast-magnetic resonance imaging(DSC-MRI)was employed to evaluate hemodynamic status.We assessed the association between the grading system and clinical characteristics(clinical symptoms,hemodynamic status and therapeutic prognosis).Results:1.A total of 83 pediatric and 131 adult(1:1.58)MMD patients were analyzed.Pediatric patients were more likely to experience a transient ischemic attack(81%),whereas adult patients were more likely to experience infarction(51%).Significantly better LMC status was found in the pediatric group than in the adult group(p=0.002).Regarding the different MMD stages(early,medium and advanced Suzuki stages 1-2,3-4 and 5-6,respectively),the prevalence of good LMC status was higher for pediatric patients in the early stage(p=0.047)and medium stage(p=0.001)than for adult patients in those stages,but there were no differences between patients in the advanced stage(p=0.547).Poor LMC status had a strong correlation with infarction(p<0.001 and p=0.017)and poor postoperative outcome(p=0.003 and p=0.043)in both pediatric and adult patients.2.The leptomenimgeal collaterals of PCA-MCA in patients with cerebral infarction MMD are significantly worse than that in MMD patients with TIA.Cerebral blood flow(CBF)and cerebral volume(CBV)of MMD patients with infarction were significantly lower than those of TIA-type MMD patients and normal adults.The CBF of TIA-type MMD patients was lower than that of normal adult.The CBV and CBF of PCA-MCA patients with poor soft meningeal compensation were significantly lower than those of well-compensated patients or normal adults.CBF values of patients with MMD with good PCA-MCA leptomenimgeal collateral were lower than those of normal adults.3.We analyzed 364 symptomatic hemispheres of 301 patients.Patients who had a history of disease progression were more likely to present with a lower collateral circulation grade(p<0.001).Ischemic patients who scored<8 points were more likely to present with infarction(p<0.001).Hemorrhagic patients who scored<8 points were more likely to have intraventricular hemorrhage(p<0.001).According to DSC-MRI,the scores were positively correlated with the relative cerebral blood volume and cerebral blood flow,and negatively correlated with the time to peak delay.Matsushima grades trended well in the ischemia hemispheres with a lower collateral grade(p=0.024)but not in the hemorrhagic hemispheres(p=0.646).Lower grades were correlated with higher recurrent stroke rates(p<0.001)and worse prognoses(p<0.001)during the follow-up period.Conclusions:1.Age is associated with LMC status in moyamoya disease patients,pediatric MMD patients have greater patency and a greater ability to establish good LMC status than adult MMD patients,and poor LMC status has a strong correlation with severe clinical symptoms and poor postoperative outcome.LMC status may be an important factor for the differences in clinical characteristics and prognosis between pediatric and adult MMD patients.2.The CBF in MCA territories of patients with MMD decreased than normal people,more obviously in infarction-type MMD patients than TIA-type MMD patients,and the status of leptomeningeal collateral of patients with cerebral infarction is worse than TIA-type MMD patients;ASL technology can be used to evaluates cerebral perfusion in patients with MMD.3.This new MMD collateral grading system correlated well with clinical symptoms,hemodynamic status and therapeutic prognosis,and it may facilitate risk stratification and prognosis predictions in patients with MMD. |
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