title: Uveal melanoma: quantitative evaluation of diffusion-weighted MR imaging in the response assessment after proton-beam therapy, long-term follow-up.
abstract: OBJECTIVE
  The purpose of this prospective study was to investigate the proton-beam-induced changes in apparent diffusion coefficient (ADC) values of ocular melanoma treated with proton-beam therapy (PBT) in patients undergoing long-term magnetic resonance imaging (MRI) follow-up and to assess whether variations in ADC constitute a reliable biomarker for predicting and detecting the response of ocular melanoma to PBT.
  
  
  METHODS
  Seventeen patients with ocular melanoma treated with PBT were enrolled. All patients underwent conventional MRI and diffusion-weighted imaging (DWI) at baseline and 1, 3, 6, and 18 months after the beginning of therapy. Tumor volumes and ADC values of ocular lesions were measured at each examination. Tumor volumes and mean ADC measurements of the five examination series were compared; correlation of ADC values and tumor regression was estimated.
  
  
  RESULTS
  Mean ADC values of ocular melanomas significantly increased already 1 month after therapy whereas tumor volume significantly decreased only 6 months after therapy. Pretreatment ADC value of ocular melanomas and early change in ADC value 1 month after therapy significantly correlated with tumor regression.
  
  
  CONCLUSIONS
  In ocular melanoma treated with PBT, ADC variations precede volume changes. Both pretreatment ADC and early change in ADC value may predict treatment response, thus expanding the role of DWI from diagnostic to prognostic.
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy. pietrofoti@hotmail.com.
authors.forename: Pietro Valerio
authors.initials: PV
authors.lastname: Foti
authors.affiliation: Department of Ophthalmology, University of Catania, Catania, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Longo
authors.affiliation: Department of Ophthalmology, University of Catania, Catania, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Reibaldi
authors.affiliation: Department of Ophthalmology, University of Catania, Catania, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Russo
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Privitera
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Corrado
authors.initials: C
authors.lastname: Spatola
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Raffaele
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Salamone
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: Farina
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Palmucci
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Musumeci
authors.affiliation: Department G.F. Ingrassia, Institute of Pathology, University of Catania, Catania, Italy.
authors.forename: Rosario
authors.initials: R
authors.lastname: Caltabiano
authors.affiliation: Unità di BioMedicina Molecolare Genomica e dei Sistemi Complessi, Genetica, Biologia Computazionale, Department G.F. Ingrassia, University of Catania, Catania, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Ragusa
authors.affiliation: Dipartimento di Oftalmologia, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Cesare
authors.initials: C
authors.lastname: Mariotti
authors.affiliation: Department of Ophthalmology, University of Catania, Catania, Italy.
authors.forename: Teresio
authors.initials: T
authors.lastname: Avitabile
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Milone
authors.affiliation: Radiodiagnostic and Radiotherapy Unit, University Hospital "Policlinico-Vittorio Emanuele", Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Giovanni Carlo
authors.initials: GC
authors.lastname: Ettorre
mesh_terms: D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D061766:Proton Therapy / Q000379:methods; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014604:Uveal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D000098943:Uveal Melanoma
keywords: Diffusion-weighted imaging; Magnetic resonance imaging; Orbit; Proton therapy; Treatment response; Uveal melanoma