Hyperdense MCA sign

Flacke, S., et A., Middle cerebral artery (MCA) susceptibility sign at susceptibility-based perfusion MR imaging clinical importance and comparison with hyperdense MCA sign at CT. Radiology, 2000. 215(2) p. 476-82. 

Hyperdense embohc material in a more distal MCA branch, within the Sylvian fissure and oriented perpendicular rather than parallel to the axial plane of imaging, may appear as a small, rounded hyperdensity ( MCA dot sign, Fig. 2.1b). One... 

Table 3.5 NCCT predictors of poor stroke outcome Hyperdense MCA or basilar artery sign on early NCCT Parenchymal hypoattenuation >1/3 of the MCA territory ASPECTS <7...

Occasionally, the diagnosis of acute ischemia can be established by NCCT because embohc material can be visualized directly, usually in the MCA or its branches. Emboli are often more radiodense than normal brain tissue, and therefore an affected proximal MCA may appear as a linear hyperdensity ( hyperdense middle cerebral artery sign or HMCA sign, Fig. 2.1c). One study found that the HMCA sign was 100% specific for MCA occlusion, but only 27% sensitive, probably because the density of embohc material is often indistinguishable from that of the normal MCA. ... 

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