title: Additional MR contrast dosage for radiologists' diagnostic performance in detecting brain metastases: a systematic observer study at 3 T.
abstract: OBJECTIVE
  To evaluate the diagnostic performance of a double-dose administration of gadolinium for brain metastases at 3 T in a systematic observer test.
  
  
  METHODS
  Postcontrast MR images of 39 patients (total 104 metastases) were obtained by 3D T1-weighted sequences with both standard and cumulative double dose contrast administration. An observer test involving 9 radiologists (5 board-certified radiologists and 4 residents) was performed, and their diagnostic performance with the two doses was compared by means of sensitivity, false-positives, reading time, and a figure-of-merit.
  
  
  RESULTS
  Compared to the standard dose, the double dose showed higher sensitivity (P < 0.0001), higher false-positive/case (P < 0.05), longer reading time (P < 0.05), and higher figure-of-merit (P < 0.0001). Particularly in small lesions (< 5 mm), sensitivity with the double dose (61.5%, P < 0.0001) was approximately twice as high as that with the standard dose (29.5%). Artifacts and blood vessels were the most common imaging findings resulting in false-positives.
  
  
  CONCLUSIONS
  The double dose improved detection for metastases smaller than 5 mm at 3 T and thus resulted in better diagnostic performance of radiologists. However, a higher dose might result in prolonged reading time and increased false-positives, presumably due to increased vessel signals and frequency of flow-related artifacts.
authors: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan, togao@radiol.med.kyushu-u.ac.jp.
authors: Osamu
authors: O
authors: Togao
authors: Akio
authors: A
authors: Hiwatashi
authors: Koji
authors: K
authors: Yamashita
authors: Kazufumi
authors: K
authors: Kikuchi
authors: Takashi
authors: T
authors: Yoshiura
authors: Hiroshi
authors: H
authors: Honda
mesh_terms: D016477:Artifacts; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006571:Heterocyclic Compounds; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium