title: Combined chemical shift imaging with early dynamic serial gadolinium-enhanced MRI in the characterization of adrenal lesions.
abstract: OBJECTIVE
  The purpose of this study was to retrospectively evaluate early dynamic serial gadolinium-enhanced and chemical-shift imaging (CSI) MRI to distinguish benign from malignant adrenal tumors.
  
  
  METHODS
  Between July 2007 and December 2011, 205 patients with 239 adrenal lesions (177 adenomas, 54 metastases, 5 pheochromocytomas, and 3 adrenal cortical carcinomas) underwent early dynamic serial gadolinium-enhanced MRI and CSI. CSI was assessed qualitatively and by calculating the adrenal index, and enhancement patterns were evaluated qualitatively and quantitatively. Statistical analyses were performed.
  
  
  RESULTS
  Most adenomas exhibited either an arterial blush or homogeneous enhancement, whereas most metastases showed early peripheral or heterogeneous enhancement. Visualization of higher enhancement on arterial and venous phases enabled differentiation of adenomas from metastases in most cases. Moderate to high signal intensity drop on CSI was seen in 95.4% of adenomas and 14.8% of metastases. In lesions with this level of signal intensity drop, 87 of 88 lesions with a capillary blush were adenomas. Early dynamic serial imaging alone was a significant (p < 0.0001) indicator of nonadenoma (area under the curve [AUC], 0.912) with optimal sensitivity of 81% and specificity of 93% for differentiating adenomas from nonadenomas. Combined analysis (CSI and early dynamic serial imaging) was also significant (p < 0.0001 and p=0.0014, respectively) for diagnosing nonadenomas (AUC, 0.983) with optimal sensitivity of 94% and specificity of 98%.
  
  
  CONCLUSIONS
  Early dynamic serial gadolinium-enhanced MRI aids in characterization of adrenal tumors, especially lesions that are categorized as indeterminate on the basis of CSI.
authors.affiliation: 1 Department of Radiology, University of North Carolina at Chapel Hill, CB# 7510, 101 Manning Dr, Chapel Hill, NC 27599-7510.
authors.forename: Karina
authors.initials: K
authors.lastname: Rodacki
authors.forename: Miguel
authors.initials: M
authors.lastname: Ramalho
authors.forename: Brian M
authors.initials: BM
authors.lastname: Dale
authors.forename: Sofia
authors.initials: S
authors.lastname: Battisti
authors.forename: Rafael O P
authors.initials: RO
authors.lastname: de Campos
authors.forename: Antonello
authors.initials: A
authors.lastname: Giardino
authors.forename: Richard C
authors.initials: RC
authors.lastname: Semelka
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000473:pathology; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D008875:Middle Aged; D009942:Organometallic Compounds; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine
keywords: adrenal adenomas; adrenal gland; adrenal metastases; contrast-enhanced MRI