title: First-pass perfusion computed tomography: initial experience in differentiating adrenal adenoma from metastasis.
abstract: OBJECTIVE
  To differentiate adrenal adenoma from metastasis in patients using perfusion computed tomography (PCT) imaging.
  
  
  METHODS
  Thirty-two patients with adrenal masses underwent first-pass PCT imaging. Of these patients, twenty-one were diagnosed with adrenal adenoma, and the others with metastases. Perfusion maps of blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability surface-area production (PS) were generated with an Advantage Windows workstation using the CT perfusion 3.0 software (General Electric Medical Systems, Milwaukee, WI). Histopathologic sections immunostained for CD34 were quantitatively evaluated for microvessel density (MVD).
  
  
  RESULTS
  The perfusion parameters such as BV, BF and PS were statistically significant different between the two groups, with adenomas showing higher mean BV (12.18 versus 3.86), BF (97.51 versus 45.99) and PS (21.73 versus 10.93) compared with metastases (p<0.05). For BV, a cutoff point of 7.30 was found to have a sensitivity of 95.2% and a specificity of 100% to differentiate between adenoma and metastasis. The sensitivity and specificity were 81.0 and 80.0%, respectively, for BF with a cutoff point of 71.96; and 85.7 and 86.7%, respectively, for PS with a cutoff point of 12.70 to differentiate adenoma and metastasis. A comparison of MVD counts from adenomas with those from metastases showed a significant difference (p<0.05). However, no significant differences were observed in the four perfusion parameters and MVD between lipid rich and lipid poor adenomas.
  
  
  CONCLUSIONS
  PCT may be useful for evaluating the neovascularization of adrenal masses and differentiating adenoma from metastasis on the basis of PCT parameters. Adenomas show higher BV, BF and PS compared with metastases. According our data, the optimal threshold BV is 7.30, resulting in a sensitivity of 95.2% and a specificity of 100% for the differentiation of adenoma from metastasis. Adrenal adenomas have similar hemodynamic profiles, which are apparently independent of the lipid content of an adenoma.
authors.affiliation: Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong, University School of Medicine, Shanghai 200025, PR China.
authors.forename: Zhong-Wei
authors.initials: ZW
authors.lastname: Qiao
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Xia
authors.forename: Yan-Bo
authors.initials: YB
authors.lastname: Zhu
authors.forename: Wei-Ping
authors.initials: WP
authors.lastname: Shi
authors.forename: Fei
authors.initials: F
authors.lastname: Miao
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000556:secondary; D018246:Adrenocortical Adenoma / Q000098:blood supply / Q000000981:diagnostic imaging*; D000328:Adult; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008833:Microcirculation; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide