Endocarditis. Endocarditis. A, Axial brain CT scan shows an isolated slight right frontal subarachnoid hyperattenuation. B, Because of clinical aggravation the next day, another brain CT was performed and demonstrated a larger right Sylvian SAH. Subsequent MR imaging showed a right middle cerebral artery infarction due to M1 occlusion (not shown), which precluded the exact identification of this SAH origin. V. Cuvinciuc et al. AJNR Am J Neuroradiol 2010;31:1355-1362 ©2010 by American Society of Neuroradiology