title: The value of 15-minute delayed contrast-enhanced CT to differentiate hyperattenuating adrenal masses compared with chemical shift MR imaging.
abstract: OBJECTIVE
  To investigate the diagnostic performance of 15-min delayed contrast-enhanced computed tomography (15-DECT) compared with that of chemical shift magnetic resonance (CSMR) imaging in differentiating hyperattenuating adrenal masses and to perform subgroup analysis in underlying malignancy and non-malignancy.
  
  
  METHODS
  This study included 478 adrenal masses in 453 patients examined with 15-DECT and 235 masses in 217 patients examined with CSMR. Relative percentage washout (RPW) and absolute percentage washout (APW) on 15-DECT, and signal intensity index (SII) and adrenal-to-spleen ratio (ASR) on CSMR were measured. Sensitivity, specificity and accuracy of 15-DECT and CSMR were analysed for characterisation of adrenal adenoma. Subgroup analyses were performed in patients with and without underlying malignancy. Attenuation and size of the masses on unenhanced CT correlated with the risk of non-adenoma.
  
  
  RESULTS
  RPW calculated from 15-DECT showed the highest diagnostic performance for characterising hyperattenuating adrenal masses regardless of underlying malignancy, and the sensitivity, specificity and accuracy were 91.7 %, 74.8 % and 88.1 %, respectively in all patients. The risk of non-adenoma increased approximately threefold as mass size increased 1 cm or as its attenuation value increased by 10 Hounsfield units.
  
  
  CONCLUSIONS
  15-DECT was more accurate than CSMR in characterising hyperattenuating adrenal masses regardless of underlying malignancy.
  
  
  CONCLUSIONS
  Delayed contrast-enhanced CT and chemical shift magnetic resonance (CSMR) characterise adrenal lesions. 15-min DECT is more accurate than CSMR in characterising hyperattenuating adrenal masses. Sensitivity of CSMR decreases as the CT attenuation of adenomas increases. Risk of non-adenoma is increased 2.9-fold as size increased by 1 cm. Risk of non-adenoma is increased 2.9-fold as attenuation increased by 10 HU.
authors.affiliation: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap-dong, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Koo
authors.forename: Hyuck Jae
authors.initials: HJ
authors.lastname: Choi
authors.forename: Hwa Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Sun-Ok
authors.initials: SO
authors.lastname: Kim
authors.forename: Kyoung-Sik
authors.initials: KS
authors.lastname: Cho
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D000307:Adrenal Gland Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D018246:Adrenocortical Adenoma / Q000000981:diagnostic imaging / Q000473:pathology; D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010673:Pheochromocytoma / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media