The “Dot CT Sign” Indicates MCA Branch Occlusion
To the Editor:
The hyperdense sylvian fissure MCA “dot” sign1 has been described as a CT marker of acute ischemia seen in 16% of a series of patients presenting with acute ischemic stroke. It is thought to represent thromboembolic occlusion of the distal MCA branches within the sylvian fissure; however, the authors of the original study1 acknowledged they had no vascular imaging to confirm this. To our knowledge, such a study has not been reported.
We cared for a 48-year-old woman who presented with the sudden onset of right arm dysesthesias and expressive dysphasia, fluctuating over the course of 3 hours before fully resolving. Treatment was with antiplatelet agents. The “dot sign” was noted on CT, and another “dot” was noted on DWI indicating infarction (Figure). The MRA indicated an occlusion in a distal MCA branch, supporting the original hypothesis.1