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@ARTICLE{Menten:141875,
      author       = {M. J. Menten and M. F. Fast and A. Wetscherek and C. M.
                      Rank and M. Kachelrieß$^*$ and D. J. Collins and S. Nill
                      and U. Oelfke},
      title        = {{T}he impact of 2{D} cine {MR} imaging parameters on
                      automated tumor and organ localization for {MR}-guided
                      real-time adaptive radiotherapy.},
      journal      = {Physics in medicine and biology},
      volume       = {63},
      number       = {23},
      issn         = {1361-6560},
      address      = {Bristol},
      publisher    = {IOP Publ.},
      reportid     = {DKFZ-2018-02132},
      pages        = {235005},
      year         = {2018},
      abstract     = {2D cine MR imaging may be utilized to monitor rapidly
                      moving tumors and organs-at-risk for real-time adaptive
                      radiotherapy. This study systematically investigates the
                      impact of geometric imaging parameters on the ability of 2D
                      cine MR imaging to guide template-matching-driven
                      autocontouring of lung tumors and abdominal organs.
                      Abdominal 4D MR images were acquired of six healthy
                      volunteers and thoracic 4D MR images were obtained of eight
                      lung cancer patients. At each breathing phase of the images,
                      the left kidney and gallbladder or lung tumor, respectively,
                      were outlined as volumes of interest. These images and
                      contours were used to create artificial 2D cine MR images,
                      while simultaneously serving as 3D ground truth. We explored
                      the impact of five different imaging parameters (pixel size,
                      slice thickness, imaging plane orientation, number and
                      relative alignment of images as well as strategies to create
                      training images). For each possible combination of imaging
                      parameters, we generated artificial 2D cine MR images as
                      training and test images. A template-matching algorithm used
                      the training images to determine the tumor or organ position
                      in the test images. Subsequently, a 3D base contour was
                      shifted to the determined position and compared to the
                      ground truth via centroid distance and Dice similarity
                      coefficient. The median centroid distance between adapted
                      and ground truth contours was 1.56 mm for the kidney,
                      3.81 mm for the gallbladder and 1.03 mm for the lung
                      tumor (median Dice similarity coefficient: 0.95, 0.72 and
                      0.93). We observed that a decrease in image resolution led
                      to a modest decrease in localization accuracy, especially
                      for the small gallbladder. However, for all volumes of
                      interest localization accuracy varied substantially more
                      between subjects than due to the different imaging
                      parameters. Automated tumor and organ localization using 2D
                      cine MR imaging and template-matching-based autocontouring
                      is robust against variation of geometric imaging parameters.
                      Future work and optimization efforts of 2D cine MR imaging
                      for real-time adaptive radiotherapy is needed to
                      characterize the influence of sequence- and anatomical
                      site-specific imaging contrast.},
      cin          = {E020 / E025},
      ddc          = {530},
      cid          = {I:(DE-He78)E020-20160331 / I:(DE-He78)E025-20160331},
      pnm          = {315 - Imaging and radiooncology (POF3-315)},
      pid          = {G:(DE-HGF)POF3-315},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:30465542},
      doi          = {10.1088/1361-6560/aae74d},
      url          = {https://inrepo02.dkfz.de/record/141875},
}