<prompt> Which of the following contrast agents is preferred in a patient with a decreased renal function to avoid contrast nephropathyAcetylcystineFenoldapamMannitolLow osmolar contrast  <response>: Low osmolar contrast agents are the contrast agents of choice in patients with pre-existing renal insufficiency.Acetylcysteine and fenoldopam may also be used to reduce contrast-induced nephropathy but these are not contrast agents. Further, these drugs have limited value for their use for this indication 