title: Whole-body diffusion-weighted imaging: is it all we need for detecting metastases in melanoma patients?
abstract: OBJECTIVE
  To investigate whether whole-body diffusion-weighted imaging (WB-DWI) alone is adequate for detecting metastases in melanoma patients, or if standard WB contrast-enhanced magnetic resonance imaging (WB-ceMRI) is required.
  
  
  METHODS
  Seventy-one WB-DWI studies were performed quarterly along with whole-body MRI including contrast-enhanced sequences (WB-ceMRI) in 19 patients with advanced melanoma. The reference standard was biopsy, other imaging investigations, or changes observed on follow-up. Findings of metastasis in separate WB-DWI and WB-DWI + WB-ceMRI readings were compared using κ statistics. Additionally, the distribution of findings was examined and calculated per body region (brain, neck, chest, abdomen, liver, pelvis, subcutaneous tissues, bones) and diagnostic accuracy (DA), sensitivity, specificity, negative predictive value, and positive predictive value were calculated per patient.
  
  
  RESULTS
  The eight examinations that were positive by the reference standard contained a total of 14 metastatic findings. With almost perfect agreement between techniques (κ = 85 %, 95 % CI 70-100 %) for detection of examinations with metastatic findings, and complete agreement in extracranial metastasis detection, 10 metastases were detected using WB-DWI and 13 using WB-DWI + WB-ceMRI. WB-DWI and WB-DWI + WB-MRI had equivalent per patient DA (79 %).
  
  
  CONCLUSIONS
  WB-DWI without additional WB-ceMRI sequences is promising for the detection of extracranial metastases in melanoma patients, but contrast-enhanced MRI is required for evaluating the brain.
authors.affiliation: Department of Radiology, European Institute of Oncology, Via Ripamonti 435, 20141, Milan, Italy, giuseppe.petralia@ieo.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Petralia
authors.forename: Anwar
authors.initials: A
authors.lastname: Padhani
authors.forename: Paul
authors.initials: P
authors.lastname: Summers
authors.forename: Sarah
authors.initials: S
authors.lastname: Alessi
authors.forename: Sara
authors.initials: S
authors.lastname: Raimondi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Testori
authors.forename: Massimo
authors.initials: M
authors.lastname: Bellomi
mesh_terms: D000008:Abdominal Neoplasms / Q000175:diagnosis / Q000556:secondary; D001859:Bone Neoplasms / Q000175:diagnosis / Q000556:secondary; D001932:Brain Neoplasms / Q000175:diagnosis / Q000556:secondary; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008113:Liver Neoplasms / Q000175:diagnosis / Q000556:secondary; D008297:Male; D008545:Melanoma / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary*; D008875:Middle Aged; D009367:Neoplasm Staging; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology; D051598:Whole Body Imaging / Q000379:methods*
chemical_list: D003287:Contrast Media