Which factors contribute to increased imaging time in Phase Contrast Angiography?

In Phase Contrast Angiography, increased imaging time can be significantly influenced by the use of multiple phase encoding axes. This is because each phase encoding axis requires additional phase encoding steps, which directly prolongs the overall scan duration. Phase Contrast Imaging relies on the velocity of blood flow, and to capture this accurately, it often necessitates sampling multiple angles or directions to gather comprehensive data. Each added phase encoding direction leads to more data points being collected, thus extending the imaging time as the sequence executes multiple phase encoding gradients.

In contrast to this option, utilizing techniques like fat suppression can sometimes streamline image acquisition by reducing artifacts from fat signals, but it doesn’t inherently extend the imaging time. Limiting the field of view generally decreases scan time as it allows for faster imaging processes since fewer slices or voxels are collected. Employing shorter repetition time (TR) and echo time (TE) times typically aims to reduce imaging time; thus, it is counterproductive in the context of increasing imaging time. Understanding these fundamental relationships in MRI physics is crucial for optimizing imaging protocols in a clinical setting.