title: Pathological manifestation of difference in washout pattern of adrenal hyperplasia on dynamic CT.
abstract: BACKGROUND
  The relationship between the washout pattern and constituent cell in adrenal hyperplasia (AH) has not been fully investigated. The purpose of this study was to elucidate the radiological or pathological factors determining the washout pattern of AH on dynamic CT.
  
  
  METHODS
  Ten patients with 14 surgically proven AHs were enrolled. Dynamic CT was scanned before (pre-contrast image) and 60 seconds (early phase) and 240 seconds (delayed phase) after administration of iodine contrast. The absolute percentage washout (APW) of each nodular lesion was calculated using the following formula: APW(%) = (TAearly-TAdelay)/(TAearly-TApre) × 100, when TApre, TAearly and TAdelay were defined as tumour attenuation values of pre-contrast, early and delayed phases, respectively. Pathologically, the clear cell ratio (CCR) constituting each nodular lesion was qualitatively assessed. Regression analysis was performed to evaluate a correlation between each pair of CCR, TApre, (TAearly-TAdelay) and APW.
  
  
  RESULTS
  There was a significant correlation between each pair of CCR, TApre and APW. CCR decreased as TApre increased (r = 0.81, P < 0.001). APW increased as CCR decreased (r = 0.80, P < 0.001) or as TApre increased (r = 0.74, P < 0.01).
  
  
  CONCLUSIONS
  The key factors of washout pattern of AH on dynamic CT were CCR and TApre. The difference in constituent cell was associated with variability in APW of AH.
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nishie
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Asayama
authors.forename: Kousei
authors.initials: K
authors.lastname: Ishigami
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kakihara
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nakayama
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ushijima
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Takayama
authors.forename: Akira
authors.initials: A
authors.lastname: Yokomizo
authors.forename: Katsunori
authors.initials: K
authors.lastname: Tatsugami
authors.forename: Junichi
authors.initials: J
authors.lastname: Inokuchi
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Fujita
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kubo
authors.forename: Shinichi
authors.initials: S
authors.lastname: Aishima
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hirakawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000000981:diagnostic imaging* / Q000378:metabolism*; D000328:Adult; D000368:Aged; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007479:Iopamidol / Q000493:pharmacokinetics*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D008954:Models, Biological; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007479:Iopamidol
keywords: adrenal hyperplasia; clear cell; compact cell; lipid; washout