title: CT attenuation of fluid in breast cysts.
abstract: OBJECTIVE
  The authors' purpose was to determine whether computed tomographic (CT) attenuation values of fluid in breast cysts could be in the range of values for soft tissue and could be correlated with protein content of the fluid.
  
  
  METHODS
  Aspirate samples from 10 simple breast cysts were analyzed for protein content, and CT attenuation values were calculated by means of a breast phantom. A corrected attenuation value for breast-cyst fluid was calculated by using sterile water as a control.
  
  
  RESULTS
  The mean corrected attenuation value for the cyst aspirate was 28.1 HU; most simple cysts have an attenuation value of only 10 HU. Protein concentration ranged from 0.9 to 2.4 g/dL. A significant, almost linear relationship was noted between protein content and attenuation value of cyst fluid (r = .85, P < .01).
  
  
  CONCLUSIONS
  The CT attenuation values of breast cysts can be in the range of those of soft tissue. This high attenuation value is correlated with the high protein content of breast-cyst fluid. Therefore, an apparent circumscribed soft-tissue mass seen within the breast at CT may represent a simple cyst.
authors.affiliation: Department of Radiology, University of Michigan, Ann Arbor 48109-0030, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Stafford-Johnson
authors.forename: M A
authors.initials: MA
authors.lastname: Helvie
authors.forename: M D
authors.initials: MD
authors.lastname: Hilborn
authors.forename: T E
authors.initials: TE
authors.lastname: Wilson
authors.forename: M M
authors.initials: MM
authors.lastname: Goodsitt
authors.forename: R O
authors.initials: RO
authors.lastname: Bude
mesh_terms: D001707:Biopsy, Needle; D001826:Body Fluids / Q000737:chemistry / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D005348:Fibrocystic Breast Disease / Q000737:chemistry / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D019047:Phantoms, Imaging; D011506:Proteins / Q000032:analysis; D013594:Syringes; D014057:Tomography, X-Ray Computed
chemical_list: D011506:Proteins