The present invention relates to formulations for use in medical or diagnostic procedures comprising a stabilizing agent alone or in combination with an osmotic agent. In one embodiment, the stabilizing agent is a natural hydrocolloid, preferably locust bean gum, and the osmotic agent is a sugar-based compound, preferably mannitol. The present invention also relates to formulations and methods for distending an anatomic segment. The present invention further relates to formulations and methods for delineating an anatomic segment on a diagnostic image, for example. The formulations of the present invention are especially suitable for use with diagnostic imaging procedures including, but not limited to, magnetic resonance imaging (MR), computer assisted tomography (CT), and CT-PET (position emission tomography), as well as other medical and therapeutic uses.