title: Clinical values of of gemstone spectral CT in diagnosing thyroid disease.
abstract: OBJECTIVE
  To quantitatively evaluate the diagnostic value of gemstone spectral CT in thyroid disease.
  
  
  METHODS
  A total of 123 patients with thyroid diseases were enrolled in the retrospective study. All the patients underwent spectral CT scan, and 39 of them underwent dual-phase enhanced scan. Iodine concentration (IC) and normalized IC (NIC) were compared between benign and malignant nodules. The optimal threshold to predict malignancy was obtained by receiver operating characteristic curve (ROC). Multivariate ROC analysis was performed to evaluate the efficacy of combining the IC (NIC) and conventional morphological characteristics.
  
  
  RESULTS
  Ten diffuse diseases and 113 nodular diseases were confirmed by clinical laboratory examination and histopathology. In total, 122 nodules (87 benign and 35 malignant) were detected, 41 nodules in enhanced cases. The IC and NIC<formula>_{VP}</formula> of malignant nodules were significantly lower than benign nodules in noncontrast and venous phase (VP) (P=0.000). The optimal IC and NIC<formula>_{VP}</formula> threshold was 0.68 mg/mL and 0.38, achieving 74.3% and 76.9% sensitivity, 66.7% and 80.0% specificity, respectively. For multivariate analysis, the area under ROC (AUC) was 0.88 and 0.94 in noncontrast and VP, respectively. Sensitivities of 77.1% and 84.6%, and specificities of 84.5% and 88.0% were achieved.
  
  
  CONCLUSIONS
  Gemstone spectral CT can generally evaluate the abnormal iodine content in thyroid disease. Lower iodine can help differentiating malignant from benign nodules. A comprehensive analysis combining spectrum parameters and morphological characteristics is suggested in differential diagnosis.
authors.affiliation: Department of Radiology, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Hong-Wen
authors.initials: HW
authors.lastname: Li
authors.affiliation: Department of Radiology, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Xing-Wang
authors.initials: XW
authors.lastname: Wu
authors.affiliation: Department of Radiology, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Radiology, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Wen-Dong
authors.initials: WD
authors.lastname: Liu
authors.affiliation: GE China CT Research Center, Beijing, China.
authors.forename: Na
authors.initials: N
authors.lastname: Gao
mesh_terms: D000328:Adult; D000465:Algorithms; D003287:Contrast Media; D005260:Female; D006801:Humans; D007455:Iodine; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007455:Iodine
keywords: Thyroid disease; computed tomography; gemstone spectral imaging