David J. Manton1, Lawrence Kenning1, Ralph Noeske2, Timo Schirmer3, Gary P. Liney4, Martin Lowry1, Martin D. Pickles1, Richard Bartlett5, Christopher Rowland-Hill
1YCR Centre for MR Investigations, The University of Hull, Hull, East Yorkshire, United Kingdom; 2Applied Science Laboratory Europe, GE Healthcare, Berlin, Germany; 3Applied Science Laboratory Europe, GE Healthcare, Muenchen, Germany; 4Radiation Physics, Hull & East Yorkshire Hospitals NHS Trust, Cottingham, East Yorkshire, United Kingdom; 5Radiology Department, Hull & East Yorkshire Hospitals NHS Trust, Hull, East Yorkshire, United Kingdom
Clinical PRESS-based proton magnetic resonance spectroscopic imaging (MRSI) choline:NAA ratios demonstrated chemical shift volume of interest misregistration-induced bias from 42% too low to 66% too high over a 79 cm 2D VOI in a homogenous phantom at 3 T. A phantom-based calibration protocol was developed to allow robust in vivo bias correction where other ameliorating methods are unavailable (e.g. on clinical scanners) or impractical (e.g. with tumours lying close to the skull). Water resonant frequency changed by 25 Hz between in vivo (body temperature) and phantom (room temperature) experiments and this was taken into account when calculating the calibration map.