Perfusion imaging using spin-labeling methods: Contrast-to-noise comparison in functional MRI applications

In this study the performance of FLASH imaging with selective inversion pre paration for functional perfusion studies was investigated, In addition to the absolute quantification of perfusion by measurement of the longitudinal relaxation times with global (T-1glob) and selective (T-1set) inversion, t he measurement of absolute (BASE) and relative (FAIR) perfusion increases b y subtraction of appropriately weighted images was also considered, The sub ject averages of absolute perfusion obtained by the quantitative method wer e 70.7 +/- 4.0 ml/100g/min in gray matter, 10.2 +/- 3.4 ml/100g/min in whit e matter, and 89.0 +/- 3.1 ml/100g/min in visual cortex. These values, as w ell as the average increase of perfusion due to visual stimulation (44.4 +/ - 3.7 ml/100g/min), agree well with respective data reported by PET and oth er MRI studies, However, for individual subjects the standard deviations ov er single ROls inside the visual cortex lay around 100% which prevented the detection of significant activation, BASE and FAIR, on the other hand, wer e able to detect significant activation in single subjects. The measured av erage perfusion increases were 51.7 +/- 6.6 ml/100g/min and 56.5 +/- 13.8%, respectively, Magn Reson Med 46:172-182, 2001, (C) 2001 Wiley-Liss, Inc.