@phdthesis{MendesPereira2019,
  author    = {Mendes Pereira, Lenon},
  title     = {Morphological and Functional Ultrashort Echo Time (UTE) Magnetic Resonance Imaging of the Human Lung},
  doi       = {10.25972/OPUS-18317},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183176},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {In this thesis, a 3D Ultrashort echo time (3D-UTE) sequence was introduced in the Self-gated Non-Contrast-Enhanced Functional Lung Imaging (SENCEFUL) framework. The sequence was developed and implemented on a 3 Tesla MR scanner. The 3D-UTE technique consisted of a nonselective RF pulse followed by a koosh ball quasi-random sampling order of the k-space. Measurements in free-breathing and without contrast agent were performed in healthy subjects and a patient with lung cancer. A gating technique, using a combination of different coils with high signal correlation, was evaluated in-vivo and compared with a manual approach of coil selection. The gating signal offered an estimation of the breathing motion during measurement and was used as a reference to segment the acquired data into different breathing phases. Gradient delays and trajectory errors were corrected during post-processing using the Gradient Impulse Response Function. Iterative SENSE was then applied to determine the fully sampled data. In order to eliminate signal changes caused by motion, a 3D image registration was employed, and the results were compared to a 2D image registration method. Ventilation was assessed in 3D and regionally quantified by monitoring the signal changes in the lung parenchyma. Finally, image quality and quantitative ventilation values were compared to the standard 2D-SENCEFUL technique. 3D-UTE, combined with an automatic gating technique and SENCEFUL MRI, offered ventilation maps with high spatial resolution and SNR. Compared to the 2D method, UTE-SENCEFUL greatly improved the clinical quality of the structural images and the visualization of the lung parenchyma. Through-plane motion, partial volume effects and ventilation artifacts were also reduced with a three-dimensional method for image registration. UTE-SENCEFUL was also able to quantify regional ventilation and presented similar results to previous studies.},
  subject      = {Kernspintomografie},
  language  = {en}
}