Transcranial Doppler Ultrasound (tcd) In Moyamoya Disease Of Moyamoya Disease And The Type And Mechanism Of Moyamoya Disease Of Ischemic Infarction,

Part1:Transcranial Doppler Ultrasonography (TCD) in Patients with Moyamoya DiseaseBackground and purposeMoyamoya disease (MMD) is an uncommon cerebrovascular disorder that is characterized by progressive bilateral steno-occlusion changes of the distal internal carotid artery and its proximal main branches within the circle of Wills. Although digital substraction angiography (DSA) is still the gold standard for diagnosing and staging MMD, it is an invasive procedure associated with non-negligible complications. Transcrnial Doppler ultrasonography (TCD) has been widely recognized as a noninvasive, cost-effective and reliable method to evaluate intracranial stenosis or occlusion. So far, studies regarding TCD findings on MMD are sparse.The purpose of this study was to obtain the TCD changes of basal arteries and collateral circulation in MMD patients with different angiographic stages (Suzuki's staging). Furthermore, we tried to establish TCD grades for MMD as a useful tool for the follow-up evaluation of MMD.MethodsWe reviewed 94 patients with MMD who admitted to the department of Neurosurgery in Beijing PLA 307 hospital between January 2006 and June 2009. All patients were confirmed to have MMD by DSA and then underwent TCD in Peking Union Medical College Hospital. Intracranial arterial involvements were classified into six angiographic stages (Suzuki's staging) in all 188 hemispheres. Using a 2-MHz transducer, bilateral middle cerebral arteries (MCA), anterior cerebral arteries (ACA) and posterior cerebral arteries (PCA) were detected through the temporal window, siphon internal carotid arteries (SCA) and ophthalmic artery (OA) were detected through the orbital window. The peak systolic velocity (PSV), end diastolic velocity (EDV), mean flow velocity (MFV) and pulsatility index (PI) were measured for each artery based on the TCD spectra. Characteristics of TCD spectrum parameters were analyzed compared with angiographic stages. Correlation between TCD grading and conventional Suzuki's angiographic stages was also examined.ResultsThe blood flow velocities of MCA were significantly higher (Kruskal-Willis H test, P= 0.000) in hemispheres with Suzuki's stage II, then reduced significantly from Suzuki's stage III. With the advance of Suzuki's stages, ACA and SCA (Kruskal-Willis H test, P< 0.05) blood flow velocities were reduced, PCA blood flow velocities were significantly increased (Kruskal-Willis H test, P< 0.005), while OA had no significant changes in blood flow velocities. In addition, the PI of MCA increased significantly (Kruskal-Willis H test, P= 0.001) with he advance of Suzuki's stages. Five grades based on TCD findings show a good correlation with Suzuki's stages (Spearman rank correlation analysis, r= 0.453, P= 0.000).ConclusionCharacteristic TCD changes can help clinician differentiate severity of MMD. TCD grading can be used as an adjunct to DSA in the follow-up evaluation of patients with MMD. Part 2:Changes of Ipsilateral Superficial Temporal Artery Spectrum after Encephaloduroarteriosynangiosis Using Pulse Doppler Ultrasonography in Moyamoya DiseaseBackground and purposeSurgical indirect revascularization is currently applied in some medical centers as a primary treatment for Moyamoya disease (MMD). The encephaloduroarteriosynangiosis (EDAS) procedure is most often used. The assessment of neovascularization after EDAS in patients with MMD usually requires repeated invasive cerebral angiography (DSA). The potential complications of DSA often limit its usefulness. TCD instruments with a 4-MHz pulse Doppler probe can also be used conveniently to obtain spectra for extracranial arteries, such as the superficial temporal artery (STA).In this study, we observed the changes of ipsilateral STA spectrum using pulse Doppler after EDAS. Moreover, we firstly investigated the capability of pulse Doppler imaging in predicting the extent of neovascularization after EDAS in MMD.MethodsData were collected on a consecutive series of 77 patients with MMD who underwent EDAS and postoperative follow-up cerebral angiography in Beijing PLA 307 hospital between January 2006 and December 2008. Among them, we included 43 patients (68 treated hemispheres) whose preoperative and postoperative TCD spectra were available. A 4-MHz pulse Doppler probe for extracranial arteries in a TCD instrument was used to acquire the spectrum of ipsilateral STA. The flow velocities, pulsatility index (PI) and flow velocity ratios of the postoperative to the preoperative for each operated STA were measured and calculated. The extent of postoperative revascularization based on the angiographic findings was classified as extensive and poor according to the area perfused by the collaterals from STA in the middle cerebral artery (MCA) territory. The pulse Doppler parameters and the extent of revascularization after EDAS on angiography were compared.ResultsThe flow velocities of the ipsilateral STA was significantly increased (t test, P= 0.000), while PI was significantly decreased (t test, P= 0.000) after surgery. Fifty of sixty-eight sides (73.5%) that underwent EDAS showed extensive collateralization on cerebral angiograms. The flow velocities were significantly higher and PI was significantly lower in patients with extensive collaterals than in those with poor collaterals. Postoperative values of the PI and the EDV ratio were significantly correlated with the postoperative angiographic grading (Spearman rank correlation analysis, r=-0.456 and r=0.532, respectively; P= 0.000). The optimal threshold values of the operated STA for the group with extensive formation of collaterals were PI≤0.95 and EDV ratio≥1.25. Application of combined PI and EDV ratio could further improve the accuracy of predicting the extent of revascularization to 83.3%for specificity. And the sensitivity was calculated as 80.0%, the positive predictive value as 93.0%, the negative predictive value as 60%, and the positive likelihood ratio as 4.0.ConclusionChanges of ipsilateral STA spectrum after EDAS could be detected by pulse Doppler ultrasonography in MMD, which are in good agreement with the DSA fingdings. TCD is a useful tool for the follow-up evaluation of post-EDAS revascularization in patients with MMD. Part 3:Lesion Patterns and Mechanism of Acute Cerebral Infarctions in Patients with Moyamoya Disease: A Diffusion-Weighted Imaging StudyBackground and purposeMoyamoya disease (MMD) is an important cause of non-atherosclerotic intracranial arterial occlusive disease. Ischemic events are the most common clinical manifestations of MMD. But patterns and mechanisms of acute ischemic stroke in patients with MMD remain unclear. Diffusion-weighted imaging (DWI) is a sensitive method that facilitates early stroke pattern identification.We sought to investigate the lesion patterns of acute cerebral infarctions using DWI and to discuss the mechanisms of stroke in patients with MMD.MethodsWe reviewed 92 acute ischemic stroke patients with MMD who admitted to the department of Neurosurgery in Beijing PLA 307 hospital between January 2004 and June 2009. DWI was performed within 1 week of onset and all patients were confirmed to have MMD by digital substraction angiography (DSA). The distribution of acute infarcts on DWI was categorized as anterior circulation infarction (including cortical infarct, border zone infarct, and perforating artery infarct), posterior circulation infarction or infacrction involved both anterior and posterior circulation. Acute lesion patterns were classified as single and multiple. Multiple ischemic lesions were defined as noncontiguous lesions on DWI. The distribution characteristics and patterns of acute infaction on DWI were analyzed. The correlation between stroke patterns and age of onset (divided into<16 years and≥16 years) as well as the correlation between stroke patterns and Suzuki's angiographic stages were also studied. ResultsSixteen (17.39%) patients had bilateral hemispheres involvement, a total of 108 hemispheres were finally included in the final analyses. Anterior circulation infarctions were found in 83 of 108 hemispheres (76.85%), posterior circulation infarctions were found in 14 hemispheres (12.96%), and in other 11 hemispheres (10.19%) infarctions were found involved both anterior and posterior circulation. Among patients with anterior circulation infarction, border zone was the most common infarction location (63/108,58.33%), followed by the cortical infarction (54/108,50.00%) and penetrating artery infarction (21/108,19.44%). Multiple acute infarcts were the most common pattern (58/83,69.88%). Concomitant border zone and cortical infarcts (21/58,36.2%), multiple border zone infarcts (14/58,24.1%) and multiple cortical infarcts (11/58,19.0%) were identified more often. For single infarcts, cortical territorial infarcts were the most common (12/25,48.0%). No isolated cortical infarcts were found. The majority of penetrating artery infarcts>2cm (14/20,70.0%). Correlations were not found neither between stroke patterns and age of onset nor between stroke patterns and DSA staging.ConclusionBilateral hemispheres or both anterior and posterior circulation could be involved in patients with MMD. A variety of infarction patterns may occur in MMD. Border zone is the most common infarction location, and multiple infarcts are the most common pattern. Stroke mechanisms in patients with MMD are similar with that in atherosclerotic carotid artery (ICA) and middle cerebral artery (MCA) diseases.