When using parallel imaging techniques, what type of scan is performed prior to acquisition?

In parallel imaging techniques, a calibration scan is performed prior to the acquisition of the actual imaging data. This scan is critical because it helps establish the necessary factors, including the sensitivity profiles of the coil elements used in the MRI system. These profiles enable the reconstruction algorithms to effectively combine the data from multiple channels, enhancing the overall speed of imaging while maintaining or improving image quality. The calibration scan provides essential baseline information that is used to correct for variations and improve the accuracy of the data collected during the actual imaging sessions.

Additionally, other types of scans mentioned, like reference scan or preparation scan, although related in different contexts, do not specifically refer to the preliminary scan that establishes calibration necessary for the operational functionality of parallel imaging techniques. Thus, the calibration scan is vital for the optimal performance of parallel imaging methodologies.