After making the final xenon-129 pre-scan adjustments and ensuring the subject is ready for the xenon-129 dose, proceed to perform the xenon-129 ventilation scan. First, load the xenon-129 ventilation sequence from the prepared protocol. Ensure all pulse sequence parameters are as desired and set proper scan execution settings.
Select the field of view, or FOV size, and center location based on the localizer results. Aim for the center of the FOV to coincide with the center of the lungs in all three dimensions and the FOV to be large enough to comfortably contain the entire chest cavity, including the entirety of both lungs. Bring the xenon-129 dose bag intended for the ventilation scan from the polarization measurement station into the scanner room.
Hold or place the dose bag near the subject. Avoid regions near the bore opening where the magnetic field strength changes rapidly. Assist the subject in inhaling the xenon-129 dose from the bag, following the already-coached inhalation procedure.
Execute the scan immediately upon hearing the signal go"from the individual assisting the subject. Monitor the subject while the scan proceeds. Following the scan, monitor the subject's heart rate and SPO2 using the pulse oximeter and monitor for transient central nervous system effects via verbal communication with the subject.
If no significant deviations from baseline occur, then after waiting for at least two minutes, another xenon-129 dose can be administered. The ventilation images from a healthy individual are shown here. A high xenon-129 signal can be observed throughout the lungs in these images, and no ventilation impairment is evident in this individual.
This figure depicts an individual with alpha-1 antitrypsin deficiency in which severe ventilation impairment can be easily detected by observing the patchy appearance of the xenon-129 images. Similarly, severe ventilation impairment can be seen in this figure depicting an individual with severe cystic fibrosis. The images shown here depicts an individual with chronic obstructive pulmonary disease in which more subtle ventilation defects can be noted.
