Figure 9e. Carotid artery involvement in an 18-month-old boy with acute left otomastoiditis but no neurologic symptoms. (a) Axial CT scan of the temporal bone obtained at admission shows mastoid disease without evidence of complications. Cranial CT also showed no evidence of complications. Owing to persistent fever and otorrhea, a second CT examination was performed 3 days later. (b) Axial CT scan shows abnormal enhancement of the left sigmoid sinus (arrow). MR imaging was performed the same day. (c) Axial MR venogram shows thrombosis of the left lateral and sigmoid sinuses. (d) Coronal gadolinium-enhanced T1-weighted MR image shows associated pachymeningeal enhancement. (e, f) Axial gadolinium-enhanced T1-weighted MR image (e) and coronal MR angiogram (f) show unsuspected markedly decreased flow in the left internal carotid artery. The patient was quickly treated with surgical mastoid drainage and broad-spectrum antibiotics. (g, h) Follow-up coronal MR images obtained 1 week (g) and 2 weeks (h) later show slow recovery of normal flow in the left carotid artery.