title: Accuracy and reliability of thyroid volumetry using spiral CT and thyroid volume in a healthy, non-iodine-deficient Chinese adult population.
abstract: OBJECTIVE
  The purpose of this study was to assess the accuracy and reliability of thyroid volumetry using spiral CT and to investigate thyroid volumes for a healthy, non-iodine-deficient adult population in southwestern region of China.
  
  
  METHODS
  Spiral CT was performed in phantoms and adult subjects with normal thyroid, and the volumes were measured by observers with 5 years or more of CT experience. The phantom volumes and the thyroid volumes of all subjects were noted.
  
  
  RESULTS
  For the thyroid phantoms, there was no significant difference between the true and CT calculated volumes (t = 0.862, P = 0.399), and the correlation was excellent (ICC = 0.9995, P = 0.000). In the subjects for reliability analysis, the intraobserver or interobserver differences for CT volumetric measurement of thyroid were not significant (P > 0.05). The intraobserver or interobserver correlations were very high (ICC > 0.99, P < 0.001). In the subjects for population analysis, the median of the thyroid volumes was 11.45 cm(3). The nonparametric Mann-Whitney U-test showed no significant difference for the thyroid volume between sexes (U = 4388.00, Z = -1.118, P = 0.264). The nonparametric Kruskall-Wallis test showed no significant difference in all age groups (χ(2) = 13.466, P = 0.062). There was a slight negative correlation between the thyroid volume and age (r(s) = -0.166, P = 0.019).
  
  
  CONCLUSIONS
  The accuracy and reliability of multi-slice spiral CT in measuring thyroid volume are very high. The thyroid volumes are not significantly difference between genders or among decades for the healthy, non-iodine-deficient adult population in southwestern region of China.
authors.affiliation: Department of Radiology, The Second Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Yuzhong District, Chongqing 400010, People's Republic of China. shujiannc@163.com
authors.forename: Jian
authors.initials: J
authors.lastname: Shu
authors.forename: Jiannong
authors.initials: J
authors.lastname: Zhao
authors.forename: Dajing
authors.initials: D
authors.lastname: Guo
authors.forename: Yindeng
authors.initials: Y
authors.lastname: Luo
authors.forename: Weijia
authors.initials: W
authors.lastname: Zhong
authors.forename: Weibo
authors.initials: W
authors.lastname: Xie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007455:Iodine / Q000172:deficiency; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013961:Thyroid Gland / Q000000981:diagnostic imaging*; D036542:Tomography, Spiral Computed / Q000295:instrumentation / Q000379:methods*; D055815:Young Adult
chemical_list: D007455:Iodine