To investigate the value of hyperintense vessel signs (HVS) on fluid-attenuated inversion recovery (FLAIR) sequence for assessing the patterns of collateral blood flow in adult moyamoya disease (MMD).

Forty-one adult patients with non-hemorrhagic MMD retrieved from Nanjing Stroke Registry Program between August 2008 and January 2011 were identified by digital cerebral angiography and performed the examination of FLAIR sequence in Jinling hospital. According to the different sites of HVS located in the territory of the middle cerebral artery, the patterns of HVS were classified into grades 0—3: Grade 0, absence of HVS; Grade 1, HVS limited in the cerebral sulci of temporal lobe and Sylvian fissure; Grade 2, HVS in the cerebral sulci of frontal and parietal lobe regions and Sylvian fissure; and Grade 3, HVS in the combined territories of Grade 1 and Grade 2. According to the intracerebral collateral blood flow, steno-occlusions of the arteries were classified into three types: Type 1, residual antegrade flow across steno-occlusive lesions; Type 2, retrograde flow via leptomeningeal vessels; Type 3, the combined collateral blood flow of Type 1 and Type 2. The relationship between the patterns of intracerebral collateral blood flow and the location of HVS was analyzed.

Of 41 adult patients with non-hemorrhagic MMD, there were 3 patients presented with unilateral vascular lesions and 38 with bilateral vascular lesions, so the total number of vascular lesions of the cerebral hemispheres was 79. Because three patients showed the absence of HVS in bilateral hemispheres, the total number of the presence of HVS of the cerebral hemispheres was 73. Therefore, the percentage of the presence of HVS was 92.4% (73/79) in vascular lesions of the cerebral hemispheres. Importantly, the patterns of slow collateral blood flow corresponding to Grade 1 HVS were all antegrade (7/7); the collateral patterns corresponding to Grade 2 HVS were mainly retrograde leptomeningeal flow (95.0%, 19/20); and the patterns corresponding to Grade 3 HVS were mainly slow combined collateral blood flow(84.8%, 39/46). Furthermore, with the changing sites of HVS from the cerebral sulci of temporal lobe to the cerebral sulci of frontal and parietal lobe regions, the directions of collateral flow changed with a shift from antegrade to retrograde, which was statistically significant.

The different locations of HVS can reflect the different patterns of collateral blood flow, and the locations of HVS may predict the directions of intracerebral collateral blood flow in adult MMD patients.