When parallel imaging techniques are utilized, a low resolution __________ is acquired prior to the acquisition.

In the context of parallel imaging techniques in MRI, a low-resolution calibration scan is essential for optimizing the imaging parameters and improving overall image quality. This calibration scan involves the acquisition of data that allows the system to effectively estimate the necessary k-space information for reconstructing high-resolution images.

By using a low-resolution scan, which requires less time and fewer resources, the MRI system establishes a baseline for the parallel imaging algorithms to work with. These algorithms rely on the calibration data to reduce scan time while maintaining sufficient image quality, ultimately allowing for the acceleration of the imaging process. Thus, the calibration scan plays a pivotal role in the efficiency and effectiveness of parallel imaging, ensuring that accurate and high-quality images can be produced while minimizing the disadvantages of longer acquisition times.