title: Different diagnostic values of imaging parameters to predict pseudoprogression in glioblastoma subgroups stratified by MGMT promoter methylation.
abstract: OBJECTIVE
  The aim of this study was to determine whether diffusion and perfusion imaging parameters demonstrate different diagnostic values for predicting pseudoprogression between glioblastoma subgroups stratified by O6-mythylguanine-DNA methyltransferase (MGMT) promoter methylation status.
  
  
  METHODS
  We enrolled seventy-five glioblastoma patients that had presented with enlarged contrast-enhanced lesions on magnetic resonance imaging (MRI) one month after completing concurrent chemoradiotherapy and undergoing MGMT promoter methylation testing. The imaging parameters included 10 or 90 % histogram cutoffs of apparent diffusion coefficient (ADC10), normalized cerebral blood volume (nCBV90), and initial area under the time signal-intensity curve (IAUC90). The results of the areas under the receiver operating characteristic curve (AUCs) with cross-validation were compared between MGMT methylation and unmethylation groups.
  
  
  RESULTS
  MR imaging parameters demonstrated a trend toward higher accuracy in the MGMT promoter methylation group than in the unmethylation group (cross-validated AUCs = 0.70-0.95 and 0.56-0.87, respectively). The combination of MGMT methylation status with imaging parameters improved the AUCs from 0.70 to 0.75-0.90 for both readers in comparison with MGMT methylation status alone. The probability of pseudoprogression was highest (95.7 %) when nCBV90 was below 4.02 in the MGMT promoter methylation group.
  
  
  CONCLUSIONS
  MR imaging parameters could be stronger predictors of pseudoprogression in glioblastoma patients with the methylated MGMT promoter than in patients with the unmethylated MGMT promoter.
  
  
  CONCLUSIONS
  • The glioblastoma subgroup was stratified according to MGMT promoter methylation status. • Diagnostic values of diffusion and perfusion parameters for predicting pseudoprogression were compared. • Imaging parameters showed higher diagnostic accuracy in the MGMT promoter methylation group. • Imaging parameters were independent to MGMT promoter methylation status for predicting pseudoprogression. • Imaging biomarkers might demonstrate different diagnostic values according to MGMT promoter methylation.
authors.affiliation: Department of Radiology, Catholic Kwandong University College of Medicine, Catholic Kwandong University International St. Mary's Hospital, 25, Simgok-ro 100beon-gil, Seo-gu, Incheon, 22711, Republic of Korea.
authors.forename: Ra Gyoung
authors.initials: RG
authors.lastname: Yoon
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, Republic of Korea. radhskim@gmail.com.
authors.forename: Ho Sung
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Radiology, Dankook Unversity Hospital, San 16-5, Anseo-dong, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea.
authors.forename: Wooyul
authors.initials: W
authors.lastname: Paik
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, Republic of Korea.
authors.forename: Woo Hyun
authors.initials: WH
authors.lastname: Shim
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, Republic of Korea.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, Republic of Korea.
authors.forename: Jeong Hoon
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000378:metabolism; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000235:genetics / Q000473:pathology; D059248:Chemoradiotherapy; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000235:genetics*; D045643:DNA Repair Enzymes / Q000235:genetics; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000235:genetics / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic / Q000235:genetics; D012372:ROC Curve; D012189:Retrospective Studies; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; D045643:DNA Repair Enzymes
keywords: Diffusion-weighted imaging; Glioblastoma; MGMT promoter methylation; Perfusion MR; Pseudoprogression