title: Contrast-enhanced synthetic MRI for the detection of brain metastases.
abstract: BACKGROUND
  Synthetic magnetic resonance imaging (MRI), a technique that enables creation of various contrast-weighted images from a single MRI quantification scan, is a useful clinical tool. However, there are currently no reports examining the use of contrast-enhanced synthetic MRI for detecting brain metastases.
  
  
  OBJECTIVE
  To assess whether contrast-enhanced synthetic MRI is suitable for detecting brain metastases.
  
  
  METHODS
  Ten patients with a combined total of 167 brain metastases who underwent quantitative MRI and conventional T1-weighted inversion recovery fast spin-echo (conventional T1IR) MRI before and after administration of a contrast agent were included in the study. Synthetic T1IR and T1-weighted (synthetic T1W) images were produced after parameter quantification. Lesion-to-white matter contrast and contrast-to-noise ratio were calculated for each image. The number of visible lesions in each image was determined by two neuroradiologists.
  
  
  RESULTS
  The mean lesion-to-white matter contrast and mean contrast-to-noise ratio of the synthetic T1IR images were significantly higher than those of the synthetic T1W (P < 0.001 and P < 0.001, respectively) and conventional T1IR (P = 0.04 and P = 0.002, respectively) images. Totals of 130 and 124 metastases were detected in the synthetic T1IR images by the first and second radiologists, respectively. The corresponding numbers were 91 and 85 in the synthetic T1W images and 119 and 119 in the conventional T1IR images. Statistical significance was not found among detected numbers of lesions.
  
  
  CONCLUSIONS
  Synthetic T1IR imaging created better contrast compared with synthetic T1W or conventional T1IR imaging. The ability to detect brain metastases was comparable among these imaging.
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan; Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Akifumi
authors.initials: A
authors.lastname: Hagiwara
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hori
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Michimasa
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Christina
authors.initials: C
authors.lastname: Andica
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan; Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan.
authors.forename: Misaki
authors.initials: M
authors.lastname: Nakazawa
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan; Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan.
authors.forename: Kouhei
authors.initials: K
authors.lastname: Tsuruta
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Nao
authors.initials: N
authors.lastname: Takano
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Sato
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Hamasaki
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Kanako Kunishima
authors.initials: KK
authors.lastname: Kumamaru
authors.affiliation: Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
keywords: Magnetic resonance imaging (MRI); T1-weighted inversion recovery; brain; contrast-enhanced MRI; metastases; synthetic MRI