Objectives
Cystic lesions and abscesses of the neck contain fluids that vary in viscosity and content. The purpose of this study was to characterize the fluid areas in cystic and abscess lesions using apparent diffusion coefficients (ADCs).
Methods
Lesion-based ADCs (overall ADCs) and pixel-based ADCs (ADC mapping) of the fluid areas in cystic lesions (n = 25) and abscesses (n = 17) were determined using b values of 500 and 1000 s/mm2. The fluid areas were defined as hyperintense areas on fat-suppressed T2-weighted images and/or non-enhanced images.
Results
Cystic lesions and abscesses were categorized into two groups on the basis of the overall ADCs of the fluid areas: group A included ranulas, lymphangiomas, parotid cysts, thyroglossal duct cysts, and mucous retention cysts (2.38 × 10−3 ± 0.26 × 10−3 mm2/s; range 1.97 × 10−3–2.93 × 10−3 mm2/s), whereas group B included epidermoid cysts, branchial cleft cysts, and abscesses (0.73 × 10−3 ± 0.37 × 10−3 mm2/s; range 0.36 × 10−3–1.53 × 10−3 mm2/s). The group A cystic lesions displayed ADC mapping profiles with 85–100% areas of high or intermediate ADCs (>1.6 × 10−3 mm2/s). In contrast, the group B lesions exhibited ADC mapping profiles with 86–100% areas of low or extremely low ADCs (<1.6 × 10−3 mm2/s). Combined use of the ADCs and ADC mapping criteria effectively (85–100% accuracy) discriminated the different types of cystic lesions and abscesses in the present study cohort.
Conclusions
The fluid areas in cystic and abscess lesions of the neck can be characterized by ADCs.