title: Characterization of orbital masses by multiparametric MRI.
abstract: OBJECTIVE
  DWI and dynamic contrast enhanced (DCE) MR imaging are techniques that allow insight to tumor vascularity and cellularity. We evaluated the diagnostic performance of multiparametric MRI (mp-MRI) in distinguishing benign from malignant orbital masses using standard anatomic imaging (sAI), DWI and DCE.
  
  
  METHODS
  This prospective IRB approved study with written informed consent included 65 patients. mp-MRI at 3 Tesla including DWI and DCE was performed in all patients. Parametric maps were generated for obtaining the perfusion parameters including K(trans), kep, ve and iAUC and time-signal intensity curves were recorded to determine the curve pattern. Two radiologists rated the likelihood of malignancy on a five-point scale in three separate, randomized reading sessions (initially only sAI, afterwards sAI+either DWI or DCE and finally sAI+DWI+DCE). Data was statistically analyzed.
  
  
  RESULTS
  33 Patients had malignant orbital masses and 32 patients had benign orbital masses (reference standard histopathology in 35 cases and clinical follow-up in 30 patients). The mean ADC of malignant masses differed significantly from the mean (SD) ADC of benign masses (0.825 [0.437]×10(-3)mm(2)/s and 1.257 [0.576]×10(-3)mm(2)/s, respectively) (p=0.001). K(trans), kep and iAUC were significantly higher in malignant masses (p<0.01). The reading of sAI only resulted in a moderate specificity but poor sensitivity in differentiating benign from malignant lesions. Adding DWI and DCE images improved specificity and sensitivity considerably, being the highest for the combined reading of all sequences.
  
  
  CONCLUSIONS
  mp-MRI is a helpful tool in differentiating malignant orbital lesions from benign masses and should therefore be included in the routine diagnostic protocol for orbital imaging.
authors.affiliation: Department of Radiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany.
authors.forename: Sa-Ra
authors.initials: SR
authors.lastname: Ro
authors.affiliation: Department of Radiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany. Electronic address: patrick.asbach@charite.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Asbach
authors.affiliation: Department of Neuroradiology, Charité-Universitätsmedizin Berlin, Campus Charité Mitte, Charitéplatz 1, 10117 Berlin, Germany.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Siebert
authors.affiliation: Department of Ophthalmology, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Eckart
authors.initials: E
authors.lastname: Bertelmann
authors.affiliation: Department of Radiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamm
authors.affiliation: Department of Radiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Erb-Eigner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000473:pathology; D009918:Orbital Neoplasms / Q000473:pathology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media
keywords: Diffusion weighted imaging; Dynamic contrast enhanced imaging; Multiparametric MRI; Orbital MRI; Orbital masses