title: Feasibility and evaluation of dual-source transmit 3D imaging of the orbits: Comparison to high-resolution conventional MRI at 3T.
abstract: OBJECTIVE
  To prospectively compare the image quality and diagnostic performance of orbital MR images obtained by using a dual-source parallel transmission (pTX) 3D sequence (Sampling Perfection with Application optimized Contrasts using different flip angle Evolution, SPACE) with the image quality of conventional high-resolution standard protocol for clinical use in patients at 3T.
  
  
  METHODS
  After obtaining institutional review board approval and patient consent, 32 patients with clinical indication for orbital MRI were examined using a high-resolution conventional sequences and 3D pTX SPACE sequences. Quantitative measurements, image quality of the healthy orbit, incidence of artifacts, and the subjective diagnostic performance to establish diagnosis was rated. Statistical significance was calculated by using a Student's t-test and nonparametric Wilcoxon signed rank test.
  
  
  RESULTS
  Length measurements were comparable in the two techniques, 3D pTX SPACE resulted in significant faster image acquisition with higher spatial resolution and less motion artifacts as well as better delineation of the optic nerve sheath. However, estimated contrast-to-noise and signal-to-noise and overall image quality as well as subjective scores of the conventional TSE imaging were rated significantly higher. The conventional MR sequences were the preferred techniques by the readers.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of 3D pTX SPACE of the orbit resulting in a rapid acquisition of isotropic high-resolution images. Although no pathology was missed in 3D pTX SPACE, conventional MRI techniques showed the higher diagnostic confidence in our study, presumably due to the higher signal-to-noise and contrast-to-noise ratios. We observed high-resolution TSE imaging to be the preferred technique, 3D pTX SPACE cannot replace conventional MRI so far.
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076, Germany. Electronic address: achim.seeger@gmx.de.
authors.forename: Achim
authors.initials: A
authors.lastname: Seeger
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076, Germany. Electronic address: maximilian.schulze@med.uni-tuebingen.de.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schulze
authors.affiliation: University Eye Hospital, Department of Ophthalmology, Eberhard-Karls-University, Schleichstrasse 12, Tübingen 72076, Germany. Electronic address: fschuettauf@uni-tuebingen.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Schuettauf
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076, Germany. Electronic address: uwe.klose@med.uni-tuebingen.de.
authors.forename: Uwe
authors.initials: U
authors.lastname: Klose
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076, Germany. Electronic address: ulrike.ernemann@med.uni-tuebingen.de.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ernemann
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076, Germany. Electronic address: till-karsten.hauser@med.uni-tuebingen.de.
authors.forename: Till-Karsten
authors.initials: TK
authors.lastname: Hauser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016477:Artifacts; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000473:pathology*; D009916:Orbital Diseases / Q000175:diagnosis*; D011446:Prospective Studies; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: MRI; Orbit; Parallel transmit; Reduced FOV; SPACE; pTX