CT and MRI findings of otogenic sigmoid sinus thrombophlebitis / 中国耳鼻咽喉头颈外科

ABSTRACT

OBJECTIVE To explore the CT and MRI appearances of otogenic sigmoid sinus thrombophlebitis(SST) and abscess. METHODS The HRCT, plain MRI, magnetic resonance venography(MRV), enhanced MRI findings in 11 patients with otogenic SST were retrospectively analyzed. RESULTS On CT, the bony wall of sigmoid sinus was eroded in 10 cases (10/11), and air bubbles were found in or around sigmoid sinus in 4 cases. On plain MRI, sigmoid sinus flow void effect disappeared in all 11 cases. SST manifested as high signal on T2W1 in all 11 cases, and as low signal on T1WI in 2 cases, isointense signal on T1WI in 6 cases, high signal on T1WI in 3 cases. Contrast enhancement MRI showed enhancement in wall of venous sinus, but venous sinus thrombosis did not enhanced, but showed as irregular filling defect or empty triangle. MRV showed that involved venous sinus was not visualized. CONCLUSION CT can show the erosion of the bony wall of sigmoid sinus which may indicate the SST; and if air bubbles are found around or in the sigmoid sinus, the abscess around or in the sigmoid sinus should be doubted. Conventional MRI combined with MRV are effective and noninvasive methods in the diagnosis of SST.