Oxygen-enhanced MRI of the lung: Optimized calculation of difference images
Dietrich O, Fasol U, Peller M, Losert C, Schoenberg S, Nikolaou K, Reiser M
Ludwig Maximilian University of Munich
The purpose of this study was to analyze how the calculated relative signal increase (&[Delta]Srel) in oxygen-enhanced lung MRI depends on the intermediary signal observed immediately after switching the gas supply. 420 repetitions (1:air, 2:O2, 3:air, 4:O2) were continuously acquired in 10 healthy volunteers. Data was post-processed discarding between 0 and 19 repetitions after each change of gas supply before calculating &[Delta]Srel. The averaged &[Delta]Srel increases from 9.4% to 17.4% with increasing number of discarded acquisitions; the ratio of &[Delta]Srel and spatial standard deviation of &[Delta]Srel has a maximum at 5 to 8 discarded acquisitions.