Which of the following is most likely to cause zipper artifacts?

• A. Patient movement
• B. Scanner room door being left open during acquisition
• C. Incorrect coil selection
• D. Low bandwidth

Answer: (B)

Zipper artifacts in MRI are typically caused by external factors that introduce noise or interference into the imaging process. In this context, the situation where the scanner room door is left open during acquisition is most likely to lead to these artifacts. An open door can allow radio frequency (RF) signals from outside the scanning area, such as from electronic devices or even ambient RF noise, to interfere with the data being collected. This can result in variations in the signal that manifest as zipper artifacts on the resulting images, showing along the frequency encoding direction.

This phenomenon occurs because zipper artifacts are primarily created when there is a disruption in the homogeneity of the magnetic field or when unwanted signals overlap with the imaging frequencies. An open door can introduce these unwanted signals, thus directly correlating with the emergence of zipper artifacts.

Other factors, while they can impact image quality, are less directly connected to the specific cause of zipper artifacts. For instance, patient movement can lead to motion artifacts that may blur the image but does not create zipper-like lines. Incorrect coil selection can affect the sensitivity and signal quality but again does not specifically relate to zipper artifacts. Low bandwidth can result in general image artifacts, but it is not specifically tied to zipper artifacts created from external interference. Therefore, the