Contrast use at low field: a review.

The use of gadolinium-based contrast agents for magnetic resonance imaging at low fields (</=0.5 T) is reviewed. Magnetic resonance studies on low-field units represent an important subset of examinations performed in the United States. Although many fundamental principles of contrast usage apply both to high-field and low-field examinations, contrast enhancement is field dependent. Although diagnostic yield is not equivalent at all field strengths, contrast effect on low-field examinations at double doses (0.2 mmol/kg) of intravenous contrast approaches that on high-field (1.5 T) examinations at standard dose (0.1 mmol/kg). It is recommended that radiologists operating low-field units routinely employ what would otherwise be considered a double dose of a gadolinium chelate for neuroradiologic examinations.