FBIRN Scanner Calibration Methods and Recommendations
FBIRN recommends careful scanner measurements prior to attempting to combine data across sites or MRI scanners. These can be used as Quality Assurance (QA) methods to include a site’s data in a study.
These QA scans are routinely performed and used to verify and measure the scanner stability during a typical fMRI scanning sequence. The scans are performed on a 17cm spherical phantom filled with an agar gel. The scans consist of 200 separate image volumes captured over roughly a 10 minute interval. The drift, fluctuations, signal to noise ratios, and other measures indicate the scanner’s background noise relative to its stability.
- The instructions and analysis methods are available here: Function BIRN Stability Phantom QA Procedures
- To get an agar phantom, contact here.
- Examples of QA measures from various scanners are here: [link]
Figure: Images of time series maps produced by qa_calc_fbirn.m. (A) average, (B) standard deviation, (C) noise average, (D) SFNR.
