| Background: Moyamoya disease(MMD) is a chronic progressive cerebrovascular obstructive disease with unknown etiology and the feature is the intima of bilateral carotid artery terminus and/or large branch vessels(Anterior Cerebral Artery(ACA) and Middle Cerebral Artery(MCA)) thicken slowly and then arterial lumina are narrowed gradually even occluded with abnormal vascular network formed in skull bass. As the disease progresses, patients will appear various clinical symptoms, such as transient ischemia attack(TIA), cerebral infarction or cerebral hemorrhage. However, currently there is no ideal cure because the cause is unknown. And medical treatment cannot prevent the disease progression or prevent the relapse of stroke. At present, surgical revascularization surgery is considered to be the main treatment method of MMD, which can relieve MMD’s symptoms and reduce the risk of relapse stroke. There are two surgical:1. the direct revascularization,which is a direct extra-intra cranial anastomosis, and the superficial temporal artery – middle cerebral artery surgery is the most common surgery; 2. the indirect revascularization, the most common surgery is encephaloduroarteriosynangiosis(EDAS). Although the methods of two surgeries are different, the main purpose both is leading external carotid arterial blood towards the brain to improve cerebral ischemic symptoms. The existed literatures show that there are no significant different in efficacy of two surgical methods. Therefore, no matter what kind of surgery, it is important to evaluate effect of operation for judging the development and prognosis of the disease.Cerebral digital subtraction angiography(DSA) is the gold standard to evaluate the efficacy of surgical revascularization, based on the size of compensatory in newborn collateral vessels. In clinical, patients usually are required to review cerebral angiography with 6-9 months after surgery to confirm the effect of surgery and decide the following treatment. However, it is an expensive invasive examination with a certain risk, and not suitable for patients to get long-term follow-up.Transcranial Doppler sonography(TCD) is noninvasive intracranial vascular ultrasound technology invented by a Norwegian physicist Aaslid, which combines pulsed Doppler technology and 2MHz emission frequency to detect hemodynamic parameter of intracranial main artery mainly in changes of blood flow velocity, direction and spectrum, and can accurately reflect pathological state of the cerebral artery narrowed and blocked. Clinicians quickly get the favor because it is non-invasive, inexpensive and convenient, and currently there is a wide use in the diagnosis of cerebrovascular disease.In MMD, TCD has great value in screening and auxiliary diagnosis. At present, applied researches on TCD evaluating surgical results are few and mostly focus on direct revascularization surgery. In indirect operations, there is a few literatures but lacked of systematic applied research.Objective: The study used transcranial doppler sonography(TCD) to detect MMD patients’ blood flow parameters of superficial temporal artery before and after the indirect revascularization, analyzed the changes and examined its consistencies with the results of DSA. Besides, it researched the value of TCD in indirect surgery efficacy evaluation and tried to establish standards of evaluating surgical results based on TCD.Methods: A retrospective analysis to MMD patients’ clinical data in our hospital neurosurgery department from April 2011 to September 2013. The diagnostic criteria are as follow:1. Meet the diagnostic criteria of MMD published in 2012. 2. All the patients were examined by TCD and DSA at preoperative and postoperative 6-9 months. 3. All the EDAS surgery were performed by the same team. 4. Complete data of TCD and DSA. The measured parameters of TCD includes pulsatility index(PI), resistance index(RI) and mean flow velocity(MFV). And according to the results of DSA, compensatory degree of newborn collateral circulation are divided into 4 grades, grade 1 for no compensation, grade 2 for newborn collateral circular area which is less than 1/3 of the middle cerebral artery area, grade 3 for newborn collateral circular area which is between 1/3 and 2/3 of the middle cerebral artery area, grade 4 for newborn collateral circular area which is more than 2/3 of the middle cerebral artery area. Then using T test to compare the changes of TCD parameters before and after surgery and calculating change rate of PI, RI and MFV, analyzing their correlation with the results of DSA based on the spearman rank correlation. In clinical, the surgery works well if DSA is classified as grade 2 and 3, and if it is 0 and 1, it is considered poor surgical results or general. Finally, when surgery works well, calculating critical of PI, RI and MFV changed rate, using receivers operating characteristic curve(ROC).Results: There were 46 patients in accordance of conditions(male 27, female 19), and among those, 40 cases were bilateral, and 6 cases were unilateral, so there were 86 cerebral hemisphere surgery in total. After surgery, PI and RI were lower while MFV was higher than before, which had significant difference(P <0.001). And according to the results of DSA ranking, grade 0 were 18 hemispheres, grade 1 were 37 hemispheres, grade 2 were 18 hemispheres and grade 3 were 13 hemispheres. At grade 0, the P value of PI, RI and MFV of superficial temporal artery before and after surgery were 0.303, 0.423 and 0.068, respectively, which were not significant. While in the other 3 grades, the P value of PI, RI and MRV were all lower than 0.001, which were significant. The changed rate of PI, RI and MRV were in good agreement with the results of DSA ranking, which PI and RI were negative correlation to DSA classification results while MRV was positive correlation, and the correlation coefficients were-0.87947(P <0.001),- 0.89066(P <0.001), and 0.71475(P <0.001), respectively. Thresholds of good surgical effect, PI decreased 36%(S=0.9677,SPE=0.8909,P<0.001),RI decreased 27%(S=0.9032,SPE=0.9455,P<0.0001),MFV increased 111%(S=0.7419,SPE=0.9273,P<0.001).Conclusion: 1. TCD can detect superficial temporal artery hemodynamics changes after MMD indirect revascularization. 2. After surgery, if superficial temporal artery PI and RI decrease while MFV increases, it supports that the operation works well and newborn intracranial collateral circulation formed. 3. The changed rate of TCD parameter and DSA grade are in good consistency, so we can determine the compensatory extent of newborn collateral circulation according to the parameter rate of change. 4. After surgery, if superficial temporal artery PI decreases more than 36%, RI decreases more than 27% while MFV increases more than 111%, it shows that the surgery effect is good. Over all, there is highly consistent between the result of TCD and DSA in evaluating the effect of MMD indirect revascularization(EDAS). And it is a convenient and effective testing method to dynamically detect EDAS efficacy for long-term and has a high value in long-term postoperative follow-up. |
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