title: Zoomed echo-planar diffusion tensor imaging for MR tractography of the prostate gland neurovascular bundle without an endorectal coil: a feasibility study.
abstract: The purpose of this study was to assess the feasibility of zoomed echo-planar imaging (EPI) diffusion tensor imaging (DTI) with 2-channel parallel transmission (pTx) for MR tractography of the periprostatic neurovascular bundle (NVB) without an endorectal coil, and to compare its performance to that of conventionally acquired DTI.
  
  
  
  8 healthy males (28.9 ± 4.6 years) underwent pelvic phased-array coil prostate MRI on a 3T system using both zoomed-EPI DTI (z-DTI) with 2-channel pTx and conventional single-shot spin-echo EPI DTI (c-DTI) acquisitions with 6 encoding directions and b-values of 0 and 1000 s/mm(2). Fractional anisotropy (FA) maps and tractography analysis incorporating 3D visualization of the NVB were performed from each acquisition. Fiber tract counts, estimated signal-to-noise ratio (eSNR), and image quality measures of the FA maps and NVB tractography were compared. Quantitative and image quality measures were compared using Wilcoxon signed rank tests.
  
  
  
  3 of 8 subjects had no tracts detected with c-DTI acquisition, while all 8 had tracts detected with z-DTI. z-DTI acquisition yielded significantly more fiber tracts (c-DTI: 77 ± 116 tracts; z-DTI: 430 ± 228 tracts; p = 0.019) and higher eSNR (c-DTI: 2.9 ± 1.2; z-DTI: 13.17 ± 9.9; p = 0.014). Relative to c-DTI acquisitions, z-DTI FA maps showed significantly reduced artifact (p = 0.008) and reduced anatomic distortion of the prostate (p = 0.010), while z-DTI tractography showed significantly better overall visual quality (p = 0.011), tract symmetry (p = 0.010), tract coherence (p = 0.011), and subjective similarity to the actual NVB (p = 0.011).
  
  
  
  Zoomed-EPI DTI acquisition for tractography of the prostate gland NVB improves quantitative and qualitative measures of image and tract fiber quality, allowing tractography of the NVB at 3T without using an endorectal coil.
authors.affiliation: Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA. Justin.Ream@nyumc.org.
authors.forename: Justin M
authors.initials: JM
authors.lastname: Ream
authors.affiliation: Siemens Healthcare, New York, NY, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Glielmi
authors.affiliation: Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA.
authors.forename: Mariana
authors.initials: M
authors.lastname: Lazar
authors.affiliation: Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA.|Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Naomi
authors.initials: N
authors.lastname: Campbell
authors.affiliation: Imaging and Therapy Division, Siemens AG Healthcare Sector, Erlangen, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Pfeuffer
authors.affiliation: Imaging and Therapy Division, Siemens AG Healthcare Sector, Erlangen, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Schneider
authors.affiliation: Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Rosenkrantz
mesh_terms: D000328:Adult; D000465:Algorithms; D016880:Anisotropy; D056324:Diffusion Tensor Imaging; D017352:Echo-Planar Imaging; D005240:Feasibility Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D009413:Nerve Fibers, Myelinated; D011467:Prostate / Q000098:blood supply / Q000294:innervation*; D011468:Prostatectomy; D059629:Signal-To-Noise Ratio
keywords: Diffusion tensor imaging; MR tractography; Parallel transmission; Prostate gland