INCLUSION CRITERIA:  Group A: In order to be eligible to participate in this study, an individual must meet all of the following criteria:  Provision of signed and dated informed consent form by subject Stated willingness to comply with all study procedures and availability for the duration of the study Male or female, 18 years or older Subjects undergoing a clinically indicated MRI examination. Examples of medical indications include known or suspected heart failure or cardiomyopathy, chest pain with known or suspected coronary artery disease, unexplained dyspnea, valve disease, known or suspected congenital heart disease, cardiac masses and known or suspected aortic disease, exposure to cardiotoxic drugs, and systemic illnesses with known associated cardiovascular involvement.  Group B, Healthy volunteers enrolled for developmental testing and establishing reference values for the custom pulse sequences. In order to be eligible to participate in this study, an individual must meet all of the following criteria:  Provision of signed and dated informed consent form Stated willingness to comply with all study procedures and availability for the duration of the study Male or female, 18 years or older  EXCLUSION CRITERIA:  An individual who meets any of the following criteria will be excluded from participation in this study:  - Unable to undergo magnetic resonance imaging because of:  Central nervous system aneurysm clips Implanted neural stimulator Implanted cardiac pacemaker or defibrillator Cochlear implant Ocular foreign body (e.g. metal shavings) Implanted Insulin pump Metal shrapnel or bullet  unless any of the above objects have been cleared as safe for MRI according to the assessment present as clinical routine at the site.  For examinations that include contrast injection of GBCA:  renal excretory dysfunction, estimated glomerular filtration rate <= 30 mL/min/1.73m(2) body surface area. Known allergic reactions to GBCA Subjects may still be invited for non-contrast enhanced examinations or undergo MR examination with ferumoxytol as contrast agent.  For examinations that include contrast injection of ferumoxytol  -- Known allergic reactions to ferumoxytol or to mannitol excipient  For subjects with a planned pharmacological stress test with adenosine or regadenoson the following contraindications will be considered as exclusion criteria:  Bronchospastic lung disease with ongoing wheezing or history of significant reactive airway disease Second- or third- degree atrioventricular blood, sinus node disease without a functioning MR conditional pacemaker Systolic blood pressure < 90 mmHg Uncontrolled hypertension (systolic BP > 200 mmHg or diastolic BP > 110 mmHg) Recent (< 48hr) use of dipyridamole of dipyridamole- containing medications Known hypersensitivity to adenosine or regadenoson. Unstable angina, acute coronary syndrome, or less than 2- 4 days after an acute myocardial infarction For regadenoson only: seizure disorder as regadenoson may lower seizure threshold. Aminophylline should not be used in cases of seizures associated with Regadenoson. Pregnant Women. Lactating Women for administration of GBCA unless the subjects is willing to discard the milk for 24 hours after receiving gadolinium  In addition, the following exclusion criteria pertains to Group B, healthy volunteers to be considered for reference values:  Known history major illness, including, but not limited to having a hypertension diagnosis, myocardial infarction, diabetes, hyperlipidemia, cardiomyopathy, congenital heart disease, valvular disease, cerebrovascular insult or peripheral vascular disease, symptoms of angina or dyspnea, current smoker. Decisionally impaired individuals