PURPOSE: To rapidly calculate and validate subject-specific field maps based on the three-dimensional shape of the bilateral breast volume. MATERIALS AND METHODS: Ten healthy female volunteers were scanned at 3 Tesla using a multi-echo sequence that provides water, fat, in-phase, out-of-phase, and field map images. A shape-specific binary mask was automatically generated to calculate a computed field map using a dipole field model. The measured and computed field maps were compared by visualizing the spatial distribution of the difference field map, the mean absolute error, and the 80% distribution widths of frequency histograms. RESULTS: The 10 computed field maps had a mean absolute error of 38 Hz (0.29 ppm) compared with the measured field maps. The average 80% distribution widths for the histograms of all of the computed, measured, and difference field maps are 205 Hz, 233 Hz, and 120 Hz, respectively. CONCLUSION: The computed field maps had substantial overall agreement with the measured field maps, indicating that breast MRI field maps can be computed based on the air-tissue interfaces. These estimates may provide a predictive model for field variations and thus have the potential to improve applications in breast MRI.
PURPOSE: To rapidly calculate and validate subject-specific field maps based on the three-dimensional shape of the bilateral breast volume. MATERIALS AND METHODS: Ten healthy female volunteers were scanned at 3 Tesla using a multi-echo sequence that provides water, fat, in-phase, out-of-phase, and field map images. A shape-specific binary mask was automatically generated to calculate a computed field map using a dipole field model. The measured and computed field maps were compared by visualizing the spatial distribution of the difference field map, the mean absolute error, and the 80% distribution widths of frequency histograms. RESULTS: The 10 computed field maps had a mean absolute error of 38 Hz (0.29 ppm) compared with the measured field maps. The average 80% distribution widths for the histograms of all of the computed, measured, and difference field maps are 205 Hz, 233 Hz, and 120 Hz, respectively. CONCLUSION: The computed field maps had substantial overall agreement with the measured field maps, indicating that breast MRI field maps can be computed based on the air-tissue interfaces. These estimates may provide a predictive model for field variations and thus have the potential to improve applications in breast MRI.
Authors: Nicky H G M Peters; Lambertus W Bartels; Sara M Sprinkhuizen; Koen L Vincken; Chris J G Bakker Journal: J Magn Reson Imaging Date: 2009-03 Impact factor: 4.813
Authors: Ananth J Madhuranthakam; Martin P Smith; Huanzhou Yu; Ann Shimakawa; Scott B Reeder; Neil M Rofsky; Charles A McKenzie; Jean H Brittain Journal: J Magn Reson Imaging Date: 2012-01-13 Impact factor: 4.813
Authors: Lori R Arlinghaus; Richard D Dortch; Jennifer G Whisenant; Hakmook Kang; Richard G Abramson; Thomas E Yankeelov Journal: Tomography Date: 2016-12