| Background and ObjectiveSince MMD was first reported in1957in Japan, digital subtraction angiography has long been considered as the gold standard in diagnosis and evaluation of MMD. However, given that DSA is the invasive test and carries some risks, many studies places an emphasis on noninvasive imaging tool for the diagnosis and the clinical evaluationof MMD in recent years, of which the commonest one was MRI. We aim to evaluate the diagnosis value and clinical significance of MRI on MMD.MethodsClinical features and MRI of a total of98cases of MMD were retrospectively analyzed carefully. Ivy sign was scored according to the distribution and the signal intensity. All cases were confirmed separately by Suzuki classification and smog-like bllod vessel degree as well as dilatation of small artery, the incidence rate of cerebral ischemia and hemorrhage wereanalyzed statistically.ResultsAmong the total of187cerebral hemispheres with vascular lesions, ivy sign, presenting with leptomeningeal high signal on FLAIR sequence, was confirmed in125(66.8%) hemispheres, mostly located in the frontal and parietal lobes. A ccording to the grades0-3which the patterns of ivy sign were classified into, the collateral patterns corresponding to Grade I were mostly antegrade(15/16,93.6%), the patterns of collateral blood flow correspongding to Grade2were mainly retrograde(40/44,90.9%), and the patterns corresponding to Grade3were majorly slow combined collateral blood flow(90/99,93.8%). No statistical difference of Suzuki classification was found between the cerebral hemorrhage and ischemia, but the occurrence of cerebral hemorrhage was higher than that of ischemia in MMD patients with Suzuki classification â…¢-â…£. There was statistical difference between periods of smog-like bllod vessel degree for occurrence of cerebral hemorrhage and ischemia, and the occurrence of cerebral hemorrhage was higher than that of ischemia in MMD patients with period2-4of smog-like blood vessel degree. No statistic difference on dilatation of small artery was found between cerebral hemorrhage and ischemia, but the occurrence of cerebral hemorrhage was higher than that of ischemia in MMD patients when the dilatated artery was the same one.ConclusionIvy sign has its important value in the diagnosis of MMD. The different parts of ivy sign can reflect the different collateral patterns of blood flow. The present study also demonstrate no significant correlation betwwen the incidence rate of cerebral hemorrhage or ischemia and Suzuki classification in patients with MMD; the patients with MMD with higher degerr of smog-like blood vessel and dilatation of major cerebral small artery may have higher incidence rate of cerebral hemorrhage. |
