TY - JOUR T1 - CT and MRI of Pediatric Skull Lesions with Fluid-Fluid Levels JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. DO - 10.3174/ajnr.A3712 AU - S.A. Nabavizadeh AU - L.T. Bilaniuk AU - T. Feygin AU - K.V. Shekdar AU - R.A. Zimmerman AU - A. Vossough Y1 - 2013/08/22 UR - http://www.ajnr.org/content/early/2013/08/22/ajnr.A3712.abstract N2 - SUMMARY: Fluid-fluid levels can occur whenever different fluid densities are contained within a cystic or compartmentalized lesion, usually related to the evolution of hematoma or necrosis. Review of the literature demonstrated that throughout the skeletal system, the most common etiology for fluid-fluid levels is aneurysmal bone cyst, but there are no dedicated studies of the pediatric calvaria, to our knowledge. In this report, we present clinicopathologic characteristics and CT and MR imaging of 11 patients with pediatric skull mass lesions demonstrating fluid-fluid levels. MR imaging demonstrated more fluid-fluid levels compared with CT in all cases. The etiologies of skull lesions with fluid-fluid levels were Langerhans cell histiocytosis in 4 (36.6%), aneurysmal bone cysts in 3 (27.2%), cephalohematoma in 3 (27.2%), and metastatic neuroblastoma in 1 (9%). Radiologists should be aware of the other etiologies of calvarial lesions with fluid-fluid levels in the pediatric skull. Abbreviations ABCaneurysmal bone cystFFLfluid-fluid levelLCHLangerhans cell histiocytosis ER -