Holding one’s breath at the end of the exhale instead of at the end of the inhale during magnetic resonance imaging (MRI) scans of the liver can reduce respiratory motion artifacts, according to a study recently published in the American Journal of Roentgenology.

For the study, researchers from Stanford University collected both unenhanced and contrast-enhanced images of end-inspiration and end-expiration breath-holding techniques from 47 participants undergoing axial T1-weighted liver MRI. Three radiologists evaluated the quality of the images based on a rubric of one point for motion artifact-obscured to five points for no artifact involvement.  

They found that the images with the highest scores were those where the patients held their breaths at the end of an exhale. For over half of the patients, radiologists preferred end-expiration images, and end-inspiration images were highly graded for only one-fifth of the patients. The researchers note that their initial findings indicate an “involuntary relaxation of the inspiratory muscles during end-inspiratory breath-hold.”

However, technologists and radiologists had differing opinions on when is best for the patient to hold their breath. “[D]espite instructions for the MRI technologists to choose the breath-hold technique that worked better for the patient according to the unenhanced sequence acquired, our technologists may have been more comfortable with end-inspiration instructions, which may have biased them toward choosing that breath-hold technique for contrast-enhanced images,” wrote the authors.