title: Quiet T1-weighted imaging using PETRA: initial clinical evaluation in intracranial tumor patients.
abstract: OBJECTIVE
  To compare the lesion contrast and signal to noise ratio (SNR) obtained with T1-weighted pointwise encoding time reduction with radial acquisition (PETRA) to those of Magnetization-Prepared RApid Gradient-Echo (MPRAGE) for contrast-enhanced imaging of primary and metastatic intracranial tumors, and to investigate whether PETRA is able to reduce acoustic noise for improved patient comfort.
  
  
  METHODS
  Fifteen patients with intracranial tumors underwent 3 Tesla MRI including inversion-prepared PETRA and MPRAGE. The two sequences had comparable scan times, spatial resolution and spatial coverage. "Tumor conspicuity" was rated qualitatively by two radiologists, while enhancing lesion-to-white matter contrast to noise ratio (CNR) and white-matter SNR were analyzed quantitatively using paired t-tests. The acoustic noise generated by each sequence was measured.
  
  
  RESULTS
  Qualitative rating of "tumor conspicuity" by two radiologists resulted in nearly identical average scores for the two sequences. Quantitative analyses revealed that (i) there was no significant difference between the mean CNR values of the two sequences (P = 0.57), (ii) the mean SNR of PETRA was significantly higher than that of MPRAGE (P < 0.01), and (iii) the mean sound level of PETRA was significantly lower than that of MPRAGE (P < 0.01).
  
  
  CONCLUSIONS
  Inversion-prepared PETRA was found to be viable as a quiet alternative to MPRAGE for contrast-enhanced T1-weighted studies of intracranial tumors.
authors.affiliation: Department of Radiology, Tokyo Metropolitan Ebara Hospital, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ida
authors.forename: Toshiki
authors.initials: T
authors.lastname: Wakayama
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Nielsen
authors.forename: Takayuki
authors.initials: T
authors.lastname: Abe
authors.forename: David M
authors.initials: DM
authors.lastname: Grodzki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D059629:Signal-To-Noise Ratio
chemical_list: D003287:Contrast Media
keywords: PETRA (pointwise encoding time reduction with radial acquisition); contrast-enhanced T1-weighted; intracranial brain tumor; point-wise, pointwise; quiet; ultra-short TE, ultrashort TE