title: Effect of tumor volume on the enhancement pattern of parathyroid adenoma on parathyroid four-dimensional CT.
abstract: BACKGROUND
  The purpose of this study is to assess the effect of tumor volume on the enhancement pattern of parathyroid adenoma (PTA) on four-dimensional computed tomography (4D-CT).
  
  
  METHODS
  We analyzed the enhancement patterns of PTA on four-phase 4D-CT in 44 patients. Dependency of the changes of Hounsfield unit values (ΔHU) on the tumor volumes and clinical characteristics was evaluated using linear regression analyses. In addition, an unpaired t test was used to compare ΔHU of PTAs between PTA volume ≥1 cm(3) and <1 cm(3), thyroid gland, and lymph node.
  
  
  RESULTS
  PTA volume based on CT was the strongest factor on the ΔHUPre to Arterial and ΔHUArterial to Venous and ΔHUArterial to Delayed (R (2) = 0.34, 0.25, and 0.32, respectively, P < 0.001 for both). PTA ≥1 cm(3) had statistically significant greater enhancement between the unenhanced phase and the arterial phase than PTA <1 cm(3) (mean values ± standard deviations (SDs) of ΔHUPre to Arterial, 102.7 ± 33.7 and 57.5 ± 28.8, respectively, P < 0.001). PTA ≥1 cm(3) showed an early washout pattern on the venous phase, whereas PTA <1 cm(3) showed a progressive enhancement pattern on the venous phase (mean values ± SDs of ΔHUArterial to Venous, -13.2 ± 31.6 and 14.4 ± 32.7, respectively; P = 0.009).
  
  
  CONCLUSIONS
  The enhancement pattern of PTA on 4D-CT is variable with respect to PTA volume based on CT. Therefore, the enhancement pattern of PTA on 4D-CT requires careful interpretation concerning the tumor volume, especially in cases of PTA <1 cm(3).
authors: Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Department of Radiology, Dongguk University Ilsan Hospital, Goyang-si, Republic of Korea.
authors: Eun Kyoung
authors: EK
authors: Lee
authors: Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. radiologyyun@gmail.com.|Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea. radiologyyun@gmail.com.
authors: Tae Jin
authors: http://orcid.org/0000-0001-8441-4574
authors: TJ
authors: Yun
authors: Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors: Ji-Hoon
authors: JH
authors: Kim
authors: Department of Surgery, Seoul National University Hospital, Seoul, Republic of Korea.
authors: Kyu Eun
authors: KE
authors: Lee
authors: Department of Surgery, Seoul National University Hospital, Seoul, Republic of Korea.
authors: Su-Jin
authors: SJ
authors: Kim
authors: Department of Pathology, Seoul National University Hospital, Seoul, Republic of Korea.
authors: Jae-Kyung
authors: JK
authors: Won
authors: Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors: Koung Mi
authors: KM
authors: Kang
authors: Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors: Seung Hong
authors: SH
authors: Choi
authors: Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.|Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors: Chul-Ho
authors: CH
authors: Sohn
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D047368:Tumor Burden
keywords: Four-dimensional computed tomography; Hyperparathyroidism; Parathyroid adenoma; Volume