title: Ocular adnexal lymphoma: diffusion-weighted mr imaging for differential diagnosis and therapeutic monitoring.
abstract: OBJECTIVE
  To describe the magnetic resonance (MR) imaging and diffusion-weighted (DW) imaging features of ocular adnexal lymphomas (OALs), to determine the diagnostic accuracy of apparent diffusion coefficient (ADC) for discriminating OALs from other orbital mass lesions, and to assess whether variations in ADC constitute a reliable biomarker of OAL response to therapy.
  
  
  METHODS
  Institutional ethical committee approval and informed consent were obtained. In this prospective study, 114 white subjects (65 females and 49 males) were enrolled. Thirty-eight patients with histopathologically proved OAL underwent serial MR and DW imaging examination of the orbits. ADCs of OALs were compared with those of normal orbital structures, obtained in 18 healthy volunteers, and other orbital mass lesions, prospectively acquired in 58 patients (20 primary non-OAL neoplasms, 15 vascular benign lesions, 12 inflammatory lesions, 11 metastases). Interval change in ADC of OALs before and after treatment was analyzed in 29 patients. Analysis of covariance and a paired t test were used for statistical analysis.
  
  
  RESULTS
  Baseline ADCs in OALs were lower than those in normal structures and other orbital diseases (P < .001). An ADC threshold of 775 x 10(-6) mm(2)/sec resulted in 96% sensitivity, 93% specificity, 88% positive predictive value, 98.2% negative predictive value, and 94.4% accuracy in OAL diagnosis. Following appropriate treatment, 10 (34%) of 29 patients showed OAL volumetric reduction, accompanied (n = 7) or preceded (n = 3) by an increase in ADC (P = .005). Conversely, a further reduction of ADC was observed in the seven patients who experienced disease progression (P < .05).
  
  
  CONCLUSIONS
  ADC permits accurate diagnosis of OALs. Interval change in ADC after therapy represents a helpful tool for predicting therapeutic response.
authors.affiliation: Department of Neuroradiology and Neuroradiology Research Unit, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy. politi.letterio@hsr .it
authors.forename: Letterio S
authors.initials: LS
authors.lastname: Politi
authors.forename: Reza
authors.initials: R
authors.lastname: Forghani
authors.forename: Claudia
authors.initials: C
authors.lastname: Godi
authors.forename: Antonio G
authors.initials: AG
authors.lastname: Resti
authors.forename: Maurilio
authors.initials: M
authors.lastname: Ponzoni
authors.forename: Stefania
authors.initials: S
authors.lastname: Bianchi
authors.forename: Antonella
authors.initials: A
authors.lastname: Iadanza
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ambrosi
authors.forename: Andrea
authors.initials: A
authors.lastname: Falini
authors.forename: Andrés J M
authors.initials: AJ
authors.lastname: Ferreri
authors.forename: Hugh D
authors.initials: HD
authors.lastname: Curtin
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Scotti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009918:Orbital Neoplasms / Q000175:diagnosis* / Q000188:drug therapy*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents