Arterial Shrinkage

For these 50 years or longer, the diagnosis of moyamoya disease has been based on the information of the lumen of involved arteries, using cerebral angiography and MR angiography. However, this has led to some confusion in the diagnosis of the disease, such as in differentiating it from intracranial arterial stenosis caused by atherosclerosis. On the other hand, studies over the past 10 years have shown that arterial shrinkage appears specifically in affected arteries in moyamoya disease. This phenomenon may not only improve the accuracy of the diagnosis, but may also help to elucidate the still unknown etiology of the disease. In this chapter, I introduce a novel concept of arterial shrinkage specific for moyamoya disease and discuss how we should diagnose moyamoya disease more accurately than before.