title: A comparative study of fused FDG PET/MRI, PET/CT, MRI, and CT imaging for assessing surrounding tissue invasion of advanced buccal squamous cell carcinoma.
abstract: OBJECTIVE
  This study aimed to evaluate the diagnostic value of fused fluorodeoxyglucose positron emission tomography and magnetic resonance imaging (PET/MRI) compared with PET/computed tomography (CT), MRI, and CT in assessing surrounding tissue invasion of advanced buccal squamous cell carcinoma (BSCC).
  
  
  METHODS
  PET/CT and MRI were performed in 17 consecutive patients with suspected masticator space invasion of BSCC from CT images. Attenuation-corrected PET and head and neck MRI datasets were registered. For pathologic correlation, 4 regions of interest were examined, including the maxilla, mandible, pterygoid, and masseter muscle. The tumor maximal diameter, measured by different imaging modalities, was correlated with pathology results.
  
  
  RESULTS
  All PET/MRI fusions were verified as well matched using specific anatomic criteria. For pathology results, 1 patient had inflammation only, 1 had spindle cell cancer, and 15 had squamous cell cancer. Of 64 regions of interest, 20 (31.3%) harbored tumor invasion. The likelihood ratio was highest in fused PET/MRI (42.56) compared with PET/CT (25.02), MRI (22.94), and CT (8.6; all P < 0.05). The sensitivity and specificity of fused PET/MRI were also highest among the 4 modalities (90.0%/90.9%, 80.0%/84.1%, 80.0%/79.5%, and 55.0%/81.8%, respectively). The level of confidence was higher in fused PET/MRI or MRI than in PET/CT or CT (85.9%, 85.9%, 70.3%, 73.4%, respectively). The maximal lesion size was 3.0 to 6.0 cm in the pathology specimen. Regression analysis showed better agreement between fused PET/MRI and pathology results.
  
  
  CONCLUSIONS
  Fused PET/MRI is more reliable for focal invasion assessment and tumor size delineation in advanced BSCC compared with PET/CT, MRI, and CT. PET/CT has the lowest confidence level, which may limit its use in the clinical setting.
authors.affiliation: Department of Nuclear Medicine, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Huang
authors.forename: Chi-Yen
authors.initials: CY
authors.lastname: Chien
authors.forename: Wei-Che
authors.initials: WC
authors.lastname: Lin
authors.forename: Fu-Min
authors.initials: FM
authors.lastname: Fang
authors.forename: Pei-Wen
authors.initials: PW
authors.lastname: Wang
authors.forename: Chun-Chung
authors.initials: CC
authors.lastname: Lui
authors.forename: Yung-Cheng
authors.initials: YC
authors.lastname: Huang
authors.forename: Bor-Tau
authors.initials: BT
authors.lastname: Hung
authors.forename: Min-Chien
authors.initials: MC
authors.lastname: Tu
authors.forename: Chiung-Chih
authors.initials: CC
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology*; D003710:Demography; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D015588:Observer Variation; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18