title: MR imaging of the fetal brain at 1.5T and 3.0T field strengths: comparing specific absorption rate (SAR) and image quality.
abstract: OBJECTIVE
  Our two objectives were to evaluate the feasibility of fetal brain magnetic resonance imaging (MRI) using a fast spin echo sequence at 3.0T field strength with low radio frequency (rf) energy deposition (as measured by specific absorption rate: SAR) and to compare image quality, tissue contrast and conspicuity between 1.5T and 3.0T MRI.
  
  
  METHODS
  T2 weighted images of the fetal brain at 1.5T were compared to similar data obtained in the same fetus using a modified sequence at 3.0T. Quantitative whole-body SAR and normalized image signal to noise ratio (SNR), a nominal scoring scheme based evaluation of diagnostic image quality, and tissue contrast and conspicuity for specific anatomical structures in the brain were compared between 1.5T and 3.0T.
  
  
  RESULTS
  Twelve pregnant women underwent both 1.5T and 3.0T MRI examinations. The image SNR was significantly higher (P=0.03) and whole-body SAR was significantly lower (P<0.0001) for images obtained at 3.0T compared to 1.5T. All cases at both field strengths were scored as having diagnostic image quality. Images from 3.0T MRI (compared to 1.5T) were equal (57%; 21/37) or superior (35%; 13/37) for tissue contrast and equal (61%; 20/33) or superior (33%, 11/33) for conspicuity.
  
  
  CONCLUSIONS
  It is possible to obtain fetal brain images with higher resolution and better SNR at 3.0T with simultaneous reduction in SAR compared to 1.5T. Images of the fetal brain obtained at 3.0T demonstrated superior tissue contrast and conspicuity compared to 1.5T.
authors.forename: Uday
authors.initials: U
authors.lastname: Krishnamurthy
authors.forename: Jaladhar
authors.initials: J
authors.lastname: Neelavalli
authors.forename: Swati
authors.initials: S
authors.lastname: Mody
authors.forename: Lami
authors.initials: L
authors.lastname: Yeo
authors.forename: Pavan K
authors.initials: PK
authors.lastname: Jella
authors.forename: Sheena
authors.initials: S
authors.lastname: Saleem
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Korzeniewski
authors.forename: Maria D
authors.initials: MD
authors.lastname: Cabrera
authors.forename: Shadi
authors.initials: S
authors.lastname: Ehterami
authors.forename: Ray O
authors.initials: RO
authors.lastname: Bahado-Singh
authors.forename: Yashwanth
authors.initials: Y
authors.lastname: Katkuri
authors.forename: Ewart M
authors.initials: EM
authors.lastname: Haacke
authors.forename: Edgar
authors.initials: E
authors.lastname: Hernandez-Andrade
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
mesh_terms: D000328:Adult; D001921:Brain; D005260:Female; D005333:Fetus; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059906:Neuroimaging / Q000379:methods*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D011446:Prospective Studies; D055815:Young Adult