The goal of this interventional study (clinical trial) is to learn if different breath-holding techniques, with and without extra oxygen, can improve the quality of abdominal Magnetic Resonance Imaging (MRI) images in healthy adults, ages 18-75.

The main questions it aims to answer are:

• Does breath-holding at end-expiration improve image quality in abdominal MRI scans?
• Does adding oxygen while breath-holding further reduce motion artifacts in abdominal MRI scans?

Researchers will compare breath-holding with and without oxygen to see if using oxygen improves image quality during MRI scans.

Participants will:

• Be pre-screened for MRI safety and trained on breath-hold procedures
• Have one non-contrast abdominal MRI scan at the University of California San Francisco (UCSF) China Basin Imaging Center
• Use two different breath-holding techniques during the scan, with and without oxygen
• Complete one study visit lasting about 45 minutes to 1 hour

This is a within-subject, randomized crossover interventional study conducted at UCSF China Basin Imaging Center using a 3 Tesla Magnetic Resonance Imaging (3T MRI scanner). The study aims to optimize abdominal MRI protocols by evaluating the impact of breath-holding techniques, with and without oxygen supplementation, on motion artifacts and overall image quality.

Each participant will undergo non-contrast abdominal MRI scans using two breath-hold conditions: (1) Functional Residual Capacity (FRC)/end-expiration without oxygen and (2) FRC/end-expiration with preoxygenation. The order of these conditions will be randomized to control for potential order effects, and each participant will serve as their own control to reduce inter-individual variability.

T2-weighted and Magnetic Resonance Cholangiopancreatography (MRCP) sequences will be acquired during each breath-hold trial. MRI-compatible pulse oximetry will be used to monitor oxygen saturation and pulse rate throughout scanning. A radiology research nurse will be present if additional monitoring is needed based on the participant's pre-screening or intra-scan findings. Participants will receive training on breath-hold procedures prior to imaging to improve consistency and comfort during scanning.

Two board-certified radiologists, blinded to the breath-hold condition, will independently assess each image set for motion artifacts and overall image quality using a standardized 5-point grading system. The grading will range from very poor (1) to very good (5) based on sharpness, visibility of anatomical details, and presence of blurring or signal loss.

Inter-rater reliability will be evaluated using the Intraclass Correlation Coefficient (ICC). Statistical analyses will include repeated measures ANOVA to compare image quality scores across breath-holding conditions. Descriptive analyses will assess breath-hold durations and participant characteristics (e.g., age, gender) in relation to image quality and safety outcomes, including oxygen saturation and self-reported comfort.

This study involves minimal risk, does not utilize contrast agents, and is intended to support the development of motion-reduced, efficient liver MRI protocols, particularly for living liver donor evaluation. Data collected during the study will not be used for clinical decision-making.

Inclusion Criteria:

• Subject must be within 18-75 years of age;
• Subject must be able to hear and understand instructions without assistive devices;
• Subject must provide written informed consent;
• Subject has the necessary mental capacity to understand instructions, and is able to comply with protocol requirements;
• Subject is able to remain still for duration of imaging procedure (approximately 30-45 minutes)

Exclusion Criteria:

• Subjects with a weight greater than 499 lbs;
• Subjects that have metallic/conductive or electrically/magnetically active implants without Magnetic Resonance (MR) Safe or Magnetic Resonance (MR) Conditional labeling, with the exception of dental devices/fillings, surgical clips, and surgical staples determined to be safe for MRI scanning by a physician investigator;
• Subjects that have implants with MR Unsafe labeling;
• Subjects that have implants labeled as MR Conditional by the manufacturer for which the allowable conditions are not expected to be achieved by the MR environment or scan protocol;
• Subjects who have a contraindication to MRI per the screening policy of the participating site;
• Subjects with any respiratory or cardiovascular condition that could compromise safe breath holding;
• Subjects who are female and pregnant