title: Malignant pleural mesothelioma: visual assessment by using pleural pointillism at diffusion-weighted MR imaging.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of the visual assessment of malignant pleural mesothelioma (MPM) on magnetic resonance (MR) images by using two known visual markers (mediastinal pleural thickness and shrinking of the lung) and a newly introduced one (pleural pointillism).
  
  
  METHODS
  With the approval of the local ethics committee, 100 consecutive patients (mean age, 61.4 years; age range, 18-87 years; 75 men, 25 women) suspected of having MPM pleural abnormalities underwent positron emission tomography/computed tomography and MR imaging, including diffusion-weighted (DW) MR imaging, followed by explorative thoracoscopy or guided biopsy with histopathologic confirmation. Because visual assessment is still the preferred method of image interpretation, the diagnostic accuracy of mediastinal pleural thickening, shrinking lung (hemithorax volume decrease due to fibrosis), and pleural pointillism were examined. Pleural pointillism was denoted by the presence of multiple, hyperintense pleural spots on high-b-value DW images. Histopathologic findings in the surgical specimen served as the reference standard. McNemar tests with Bonferroni correction were used to assess differences in accuracy among the three examined markers.
  
  
  RESULTS
  Of 100 patients, 33 had benign pleural alterations, and 67 had malignant pleural diseases (MPDs); 57 of 67 had MPM. A total of 78 patients received a correct diagnosis (benign vs malignant) on the basis of mediastinal pleural thickening (sensitivity, 81%; specificity, 73%; accuracy, 78%); and 66 patients, on the basis of shrinking lung (sensitivity, 60%; specificity, 79%; accuracy, 66%). The correct diagnosis was indicated on the basis of pleural pointillism in 88 patients (sensitivity, 93%; specificity, 79%; accuracy, 88%).
  
  
  CONCLUSIONS
  Visual assessment of pleural pointillism on high-b-value DW images is useful to differentiate MPD from benign alterations, performing substantially better than mediastinal pleural thickness and shrinking lung, and might obviate unnecessary invasive procedures for MPM.
authors.affiliation: From the Departments of Radiology (J.C., F.D.K., W.D.W., I.R., S.D., J. Verschakelen), Thoracic Surgery (P.N., P.D.L., D.V.R.), Pneumology (C.D., J. Vansteenkiste, A.D., K.N.), and Pathology (E.V.), University Hospitals Leuven, Herestraat 49, B-3000 Leuven, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Coolen
authors.forename: Frederik
authors.initials: F
authors.lastname: De Keyzer
authors.forename: Philippe
authors.initials: P
authors.lastname: Nafteux
authors.forename: Walter
authors.initials: W
authors.lastname: De Wever
authors.forename: Christophe
authors.initials: C
authors.lastname: Dooms
authors.forename: Johan
authors.initials: J
authors.lastname: Vansteenkiste
authors.forename: Aurélie
authors.initials: A
authors.lastname: Derweduwen
authors.forename: Ilse
authors.initials: I
authors.lastname: Roebben
authors.forename: Eric
authors.initials: E
authors.lastname: Verbeken
authors.forename: Paul
authors.initials: P
authors.lastname: De Leyn
authors.forename: Dirk
authors.initials: D
authors.lastname: Van Raemdonck
authors.forename: Kristiaan
authors.initials: K
authors.lastname: Nackaerts
authors.forename: Steven
authors.initials: S
authors.lastname: Dymarkowski
authors.forename: Johny
authors.initials: J
authors.lastname: Verschakelen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008654:Mesothelioma / Q000473:pathology*; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult