The objective of this study is to characterize the safety, efficacy and pharmacokinetic profiles of Optimark at the standard clinical dose of 0.1 mmol/kg in the pediatric patient population.

Pediatric patients referred for magnetic resonance imaging (MRI) of the liver or central nervous system (CNS) will be stratified by age to one of two groups (2 through 11 and 12 through 18 years of age).

Inclusion Criteria:

• 2 thru 18 years of age
• referred for MRI of the liver or CNS
• if female and of child-bearing potential, must have negative pregnancy test within 24 hours of study drug administration
• if applicable, agree to use medically accepted method of contraception throughout the study
• if necessary, patients entering the PK subgroup must be willing to be housed within the investigational facility for a minimum of 24 hours following drug administration
• understand the requirements of the study and provide written consent to participate, agree to abide by the study requirements

Exclusion Criteria:

• previously entered into this study or a previous study using Optimark
• received investigational drug within 30 days of admission into this study or plan to participate in a clinical study prior to the end of this study's monitoring period. (patients on a research protocol using an approved drug ar acceptable)
• medical condition, serious intercurrent illness, or extenuating circumstance that would significantly decrease study compliance and all prescribed follow up
• known or suspected abnormal renal function for age or requiring dialysis during the study period
• pregnant or breastfeeding
• scheduled to undergo any contrast-enhanced examination within 7 days prior to baseline examination or during the course of this study period
• condition that is a contraindication to MRI (i.e., cardiac pacemaker, epicardial pacemaker leads, cochlear implants, ferromagnetic aneurysm clip, ferromagnetic halo device, or other condition that would preclude patient proximity to a strong external magnetic field)
• experienced a previous hypersensitivity reaction to a gadolinium-based contrast agent
• recent history of hemolytic anemia, sickle cell anemia, or other hemoglobinopathy
• undergone a surgical procedure within one week prior to study admission or are planned to undergo a surgical procedure during study participation (central line placement is acceptable)
• history of significant claustrophobia
• weighs less than 25 lbs (11 kgs)