Magnetic Resonance Imaging (MRI) Practice Test

What type of sequences are used in dynamic enhanced MRA of the mesenteric arteries?

1. Incoherent gradient echo

2. Spin echo

3. Fast spin echo

4. Gradient echo

The correct answer is: Incoherent gradient echo

Dynamic enhanced magnetic resonance angiography (MRA) of the mesenteric arteries primarily employs incoherent gradient echo sequences. This choice is correct because incoherent gradient echo sequences are particularly sensitive to changes in signal intensity that occur rapidly, which is essential for capturing the dynamic flow of contrast material through the mesenteric arteries. These sequences utilize the characteristics of gradient echoes to provide high-resolution images with a fast acquisition time, allowing for the effective visualization of blood vessels as the contrast agent is injected. In contrast, spin echo and fast spin echo sequences are generally more suited for static imaging and may not capture the rapid changes seen during the dynamic phase of contrast enhancement as effectively. They can be useful for other forms of imaging but are less optimal for dynamic assessments. Gradient echo sequences can be used in MRA as well, but incoherent gradient echo sequences grant improved contrast and temporal resolution specifically necessary for visualizing the vascular flow dynamics in situations like mesenteric MRA.