title: Comparison of accelerated T1-weighted whole-brain structural-imaging protocols.
abstract: Imaging in neuroscience, clinical research and pharmaceutical trials often employs the 3D magnetisation-prepared rapid gradient-echo (MPRAGE) sequence to obtain structural T1-weighted images with high spatial resolution of the human brain. Typical research and clinical routine MPRAGE protocols with ~1mm isotropic resolution require data acquisition time in the range of 5-10min and often use only moderate two-fold acceleration factor for parallel imaging. Recent advances in MRI hardware and acquisition methodology promise improved leverage of the MR signal and more benign artefact properties in particular when employing increased acceleration factors in clinical routine and research. In this study, we examined four variants of a four-fold-accelerated MPRAGE protocol (2D-GRAPPA, CAIPIRINHA, CAIPIRINHA elliptical, and segmented MPRAGE) and compared clinical readings, basic image quality metrics (SNR, CNR), and automated brain tissue segmentation for morphological assessments of brain structures. The results were benchmarked against a widely-used two-fold-accelerated 3T ADNI MPRAGE protocol that served as reference in this study. 22 healthy subjects (age=20-44yrs.) were imaged with all MPRAGE variants in a single session. An experienced reader rated all images of clinically useful image quality. CAIPIRINHA MPRAGE scans were perceived on average to be of identical value for reading as the reference ADNI-2 protocol. SNR and CNR measurements exhibited the theoretically expected performance at the four-fold acceleration. The results of this study demonstrate that the four-fold accelerated protocols introduce systematic biases in the segmentation results of some brain structures compared to the reference ADNI-2 protocol. Furthermore, results suggest that the increased noise levels in the accelerated protocols play an important role in introducing these biases, at least under the present study conditions.
authors: Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland; Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. Electronic address: pavel.falkovskiy@epfl.ch.
authors: Pavel
authors: P
authors: Falkovskiy
authors: German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
authors: Daniel
authors: D
authors: Brenner
authors: Siemens AG, Healthcare Sector, Erlangen, Germany.
authors: Thorsten
authors: T
authors: Feiweier
authors: Siemens AG, Healthcare Sector, Erlangen, Germany.
authors: Stephan
authors: S
authors: Kannengiesser
authors: Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland; Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors: Bénédicte
authors: B
authors: Maréchal
authors: Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland; Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors: Tobias
authors: T
authors: Kober
authors: Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland; Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors: Alexis
authors: A
authors: Roche
authors: Mayo Clinic, Department of Radiology, MN, Rochester, United States.
authors: Kaely
authors: K
authors: Thostenson
authors: Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland.
authors: Reto
authors: R
authors: Meuli
authors: Mayo Clinic, Department of Radiology, MN, Rochester, United States.
authors: Denise
authors: D
authors: Reyes
authors: German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
authors: Tony
authors: T
authors: Stoecker
authors: Mayo Clinic, Department of Radiology, MN, Rochester, United States.
authors: Matt A
authors: MA
authors: Bernstein
authors: Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors: Jean-Philippe
authors: JP
authors: Thiran
authors: Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Siemens Medical Solutions USA, Inc., Boston, MA, USA.
authors: Gunnar
authors: G
authors: Krueger
mesh_terms: D000328:Adult; D016477:Artifacts; D019985:Benchmarking; D001921:Brain / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D055815:Young Adult