Johannes Tran-Gia1, Sotirios Bisdas2, Herbert Köstler3, Uwe Klose4. 1. Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany; Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany. Electronic address: Tran_J@ukw.de. 2. Department of Diagnostic and Interventional Neuroradiology, Eberhard Karls University, Tübingen, Germany; Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, University College London Hospitals, London, United Kingdom. 3. Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany. 4. Department of Diagnostic and Interventional Neuroradiology, Eberhard Karls University, Tübingen, Germany.
Abstract
PURPOSE: To present a technique for dynamic T1 mapping. MATERIALS AND METHODS: A recently proposed model-based reconstruction entitled IR-MAP allows T1 mapping of a single slice from a single radial inversion recovery Look-Locker FLASH acquisition. To enable dynamic T1 mapping, multiple of these acquisitions are consecutively performed, each followed by a waiting period of 3s for relaxation. Next, IR-MAP is used to reconstruct an individual T1 map for each of these acquisitions. Finally, T1 errors caused by insufficient relaxation between subsequent IR pulses are iteratively corrected. RESULTS: The functionality of the proposed setup was validated in a phantom and in seven healthy volunteers. Systematic deviations between subsequent T1 maps originating from insufficient relaxation periods were effectively corrected. Additionally, the approach was successfully applied to monitor the T1 dynamic in a patient with primary lymphoma after the intravenous injection of contrast agent. CONCLUSION: The proposed setup enables dynamic T1 mapping of a single slice with a spatial resolution of 1.6 mm × 1.6 mm × 3 mm and a temporal resolution of one parameter map every 9 s. It therefore represents a new opportunity to track changes in T1 over time, as it is desirable in many applications such as dynamic contrast-enhanced MRI.
PURPOSE: To present a technique for dynamic T1 mapping. MATERIALS AND METHODS: A recently proposed model-based reconstruction entitled IR-MAP allows T1 mapping of a single slice from a single radial inversion recovery Look-Locker FLASH acquisition. To enable dynamic T1 mapping, multiple of these acquisitions are consecutively performed, each followed by a waiting period of 3s for relaxation. Next, IR-MAP is used to reconstruct an individual T1 map for each of these acquisitions. Finally, T1 errors caused by insufficient relaxation between subsequent IR pulses are iteratively corrected. RESULTS: The functionality of the proposed setup was validated in a phantom and in seven healthy volunteers. Systematic deviations between subsequent T1 maps originating from insufficient relaxation periods were effectively corrected. Additionally, the approach was successfully applied to monitor the T1 dynamic in a patient with primary lymphoma after the intravenous injection of contrast agent. CONCLUSION: The proposed setup enables dynamic T1 mapping of a single slice with a spatial resolution of 1.6 mm × 1.6 mm × 3 mm and a temporal resolution of one parameter map every 9 s. It therefore represents a new opportunity to track changes in T1 over time, as it is desirable in many applications such as dynamic contrast-enhanced MRI.
Authors: Felix Lugauer; Jens Wetzl; Christoph Forman; Manuel Schneider; Berthold Kiefer; Joachim Hornegger; Dominik Nickel; Andreas Maier Journal: MAGMA Date: 2018-01-25 Impact factor: 2.310
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