Evaluation of a New MRI Technique to Reduce Breathing-Related Artifacts in Brain Imaging

This study aims to improve the quality of brain magnetic resonance imaging (MRI) scans by testing a new imaging method that reduces distortions caused by breathing. During respiration, small movements of the chest and diaphragm can lead to subtle changes in the magnetic field within the head. These changes can introduce artifacts in certain MRI techniques, particularly susceptibility-weighted imaging (SWI), which is used to visualize veins, small hemorrhages, and iron deposits. The investigated method measures breathing-related magnetic field variations during MRI acquisition using two very short navigator signals, referred to as free induction decay (FID) navigators. These signals are used to perform dynamic off-resonance correction during image reconstruction, reducing image blurring and distortion. The method does not increase scan time and does not affect standard clinical imaging. In this study, patients scheduled for routine clinical brain MRI are asked to provide informed consent for use of their raw MRI data for research purposes. For each participant, two sets of SWI images are generated from the same acquisition: one using standard reconstruction and one using the free induction decay navigator-based dynamic off-resonance correction method (FID-DORK). The objective is to assess whether the corrected images provide improved image quality and diagnostic reliability. The study includes adult patients undergoing routine clinical MRI at Karolinska University Hospital. Image quality is evaluated using both visual assessment by neuroradiologists and quantitative measures of image variation. No additional imaging procedures, contrast agents, or scan time are required. All research data are pseudonymized prior to analysis. The hypothesis is that the dual free induction decay navigator-based correction method (FID-DORK) improves the diagnostic quality of high-resolution three-dimensional echo-planar imaging susceptibility-weighted imaging brain MRI by reducing breathing-related artifacts.

Inclusion Criteria: * Adult patients (18 years or older) * Undergoing a routine clinical brain MRI at Karolinska University Hospital * Able to understand the study information and provide written informed consent * Sequence parameters and scan protocol compatible with the research acquisition (3D-EPI SWI) Exclusion Criteria: * Patients unable to give informed consent * Standard contraindications to MRI (e.g., non-MRI safe implants, severe claustrophobia) * Clinical conditions requiring urgent imaging where research consent is not feasible * Significant motion or incomplete scans preventing creation of research images (rare)