Evaluation of Gadolinium Based Contrast Agents for Portable MR Imaging Systems

Inclusion Criteria To be eligible to participate in this study, an individual must meet all the following criteria: * Age ≥18 years Clinical indication of suspected or known brain lesion(s) with focal blood-brain barrier disruption. Preferably, at least one previously documented brain lesion with focal areas of blood-brain barrier disruption categorizable as: * intra-axial tumor(s) * extra-axial tumor(s) * infection/inflammatory lesion(s) * Cleared for portable MRI (pMRI) and intravenous GBCA administration per site policy. * Adequate peripheral venous access for contrast injection. * Able to provide informed consent and comply with brief supine imaging (pre- and post-contrast) Exclusion Criteria Participants will be excluded if they meet any of the following criteria: * Metallic clips or devices in the brain or eye. * Body weight greater than 200 kg. * Inability to fit or be positioned appropriately within the Swoop® Portable MR Imaging® System. * Inability to remain still or lie flat during the imaging period. * Not cleared for GBCA administration due to known hypersensitivity, allergy, or contraindication. * Severe renal impairment (eGFR \< 30 mL/min/1.73 m²) or acute kidney injury. * History of severe reaction to any gadolinium-based contrast agent. * GBCA administration within the prior 48 hours (or alternative clearance window defined by institution) * Known or suspected pregnancy at the time of imaging. * Any medical or behavioral condition that, in the investigator's judgment, would make participation unsafe or interfere with study completion. Subjects may be selectively enrolled or excluded to ensure inclusion of radiology finding subgroups and GBCA agents.