Potential of magnetization transfer MRI for target volume definition in patients with non‐small‐cell lung cancer |
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Authors: | Johannes FT Arnold PhD Markus Kotas MD Robert W Pyzalski PhD Eberhard D Pracht PhD Michael Flentje MD Peter M Jakob PhD |
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Institution: | 1. Department of Physics, University of Würzburg, Würzburg, Germany;2. Department of Radiation Oncology, University of Würzburg, Würzburg, Germany;3. Department of Radiology, University of Wisconsin‐Madison, Madison, Wisconsin, USA |
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Abstract: | Purpose To develop a magnetization transfer (MT) module in conjunction with a single‐shot MRI readout technique and to investigate the MT phenomenon in non‐small‐cell lung cancer (NSCLC) as an adjunct for radiation therapy planning. Materials and Methods A total of 10 patients with inoperable NSCLC were investigated using a 1.5T MR scanner. MT ratio (MTR) maps of several slices throughout the tumor were assessed. Each MTR‐map was acquired within a short breathhold. Fluorodeoxyglucose positron emission tomography (FDG‐PET) investigations were performed in addition to the MRI protocol. A total of 60 structures appearing conspicuous in FDG‐PET were compared with structures appearing conspicuous in corresponding MTR maps. Quantification of similarity between both modalities was performed using similarity index calculation. Results MTR‐maps showed different contrast than FDG‐PET images. However, structures that appeared conspicuous in FDG‐PET images, either by a marked signal enhancement or signal decrease, were found to be similarly present in MTR maps. A mean similarity index of 0.65 was calculated. MTR values of suspected atelectasis were on average lower than MTR values of tumor tissue. Conclusion The proposed MT‐MRI technique provides a high MT efficiency, while being robust and fast enough for breathhold acquisition. The results obtained encourage for further exploration of MT‐MRI as an adjunct for radiotherapy planning in NSCLC. J. Magn. Reson. Imaging 2008;28:1417–1424. © 2008 Wiley‐Liss, Inc. |
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Keywords: | non‐small‐cell lung cancer magnetization transfer target volume radiotherapy planning FDG‐PET |
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