CT and MR imaging findings of infection-free and benign second branchial cleft cysts.

ABSTRACT

PURPOSE: The present study aimed to assess CT and MR imaging findings of infection-free and benign second branchial cleft cysts (SBCCs). METHODS: Eleven patients with histopathologically confirmed infection-free and benign SBCCs underwent preoperative contrast-enhanced CT (CECT) and/or MR imaging. We assessed qualitative (presence and extent of wall thickening, degree of contrast enhancement of the thickened wall on CECT images, and signal intensity of the thickened wall on T2-weighted images) and quantitative (maximum thickness of the thickened wall) imaging findings. RESULTS: Eccentric and smooth wall thickening was observed in 11/11 (100%) patients. The wall thickening extent (percentage of the thickened wall to the circumference of the wall) was small (1%-25%) in 4/11 (36%), moderate (26%-50%) in 6/11 (54%), extensive (51%-75%) in 1/11 (9%), and diffuse (76%-100%) in 0/11 (0%) patients. Mild homogeneous enhancement of the thickened wall on CECT images was observed in 7/7 (100%) patients. The signal intensity of the thickened wall on T2-weighted images was isointense relative to that of normal lymph nodes in 7/8 (88%) and mildly hyperintense in 1/8 (12%) patient. The maximum thickness of the thickened walls ranged from 2 to 4 (mean 3.4) mm. CONCLUSIONS: Infection-free and benign SBCCs are identifiable as cysts with eccentric and smooth wall thickening on CECT and MR images. The wall thickness was almost always less than half of the wall circumference, isointense relative to normal lymph nodes, and showed mild homogeneous enhancement.