title: Preoperative assessment of thymic veins on multidetector row CT: optimization of contrast material volume.
abstract: OBJECTIVE
  Preoperative localization of the thymic veins is considered important to prevent intraoperative severe bleeding prior to video-assisted thoracoscopic thymectomy. The purpose of this study was to determine the optimal dose of contrast material for preoperative CT imaging for the detection of thymic veins on the basis of patient weight.
  
  
  METHODS
  The records of 31 patients who underwent thymectomy were examined retrospectively. All patients were scanned using an eight-channel multidetector-row computed tomography (CT) scanner at 1.25 mm collimation and a 0.625-mm reconstruction interval. CT scans were obtained after injection of 300 mg I/ml nonionic contrast material at a rate of 2 ml/s. A 90-ml contrast bolus was used for the first 16 consecutive patients (group I), and a 150-ml bolus was used for the following 15 patients (group II). The scan delay was 60 s and 90 s in groups I and II respectively. Two independent radiologists who were blinded to the surgical results evaluated the number of thymic veins observed on preoperative CT, which was later correlated with the actual number of thymic veins clipped during surgery. The responses were analyzed with respect to contrast amount by single bolus and per kilogram of body weight.
  
  
  RESULTS
  Thymic veins were correctly detected in 9 of 16 (56%) patients in group I and 14 of 15 (93%) patients in group II. Thymic vein detection was significantly better in patients who received the >or=2.0 ml/kg contrast medium compared to those who received the 1.00-1.99 ml/kg medium (P < 0.05).
  
  
  CONCLUSIONS
  An intravenous contrast material volume of 2 ml/kg (300 mg I/ml) is appropriate for the identification of thymic veins on prethymectomy CT.
authors.affiliation: Department of Radiology, Graduate School of Medicine, Osaka University, D1, 2-2 Yamadaoka, Suita, 565-0871, Japan.
authors.forename: Javzandulam
authors.initials: J
authors.lastname: Natsag
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tomiyama
authors.forename: Atsuo
authors.initials: A
authors.lastname: Inoue
authors.forename: Naoki
authors.initials: N
authors.lastname: Mihara
authors.forename: Takeshi
authors.initials: T
authors.lastname: Johkoh
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Sumikawa
authors.forename: Osamu
authors.initials: O
authors.lastname: Honda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shiono
authors.forename: Meinoshin
authors.initials: M
authors.lastname: Okumura
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D001835:Body Weight; D002277:Carcinoma / Q000150:complications / Q000000981:diagnostic imaging; D003287:Contrast Media / Q000008:administration & dosage*; D003560:Cysts / Q000150:complications / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009157:Myasthenia Gravis / Q000150:complications / Q000000981:diagnostic imaging; D011300:Preoperative Care; D012189:Retrospective Studies; D016037:Single-Blind Method; D013934:Thymectomy; D013945:Thymoma / Q000150:complications / Q000000981:diagnostic imaging; D013950:Thymus Gland / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000601:surgery; D013953:Thymus Neoplasms / Q000150:complications / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media