MRI perfusion techniques development took longer than expected.

This work seeks to develop, evaluate and use new MRI methods for non-invasive quantitative assessment of myocardial perfusion and perfusion reserve (MPR), and to compare with quantitative PET imaging.

This project aims to determine the validity of quantitative MRI perfusion methods by comparison with quantitative PET imaging. First pass dynamic contrast enhanced MRI scans will be performed at rest and during hyperemia caused by either adenosine infusion or regadenoson. After custom reconstruction and post-processing the data will be fit to a compartment model and quantitative perfusion and MPR values obtained.

On another day, the subjects will have quantitative PET imaging with O-15 labeled radioactive water. This will be done at rest and hyperemia caused by either adenosine or regadenoson. A low dose CT scan will be acquired to perform attenuation correction of the PET images. The images will be reconstructed and processed as reported in the literature to provide reference standard perfusion and MPR values. These values will be compared with those obtained by MRI.

• Inclusion Criteria:

  • All participants will be over the age of 18 and able to provide consent
  • Both healthy and subjects with cardiac disease (including atrial fibrillation but not required) will be recruited.

• Exclusion Criteria:

  • Critically ill patients, patients on ventilators, patients with unstable angina or with hypotension, asthmatics, and other patients whose medical care or safety may be at risk from undergoing an MRI examination will be excluded.
  • Patients with claustrophobia will also be excluded from the study if this cannot be controlled with standard methods (valium or benadryl).
  • Patients with contraindication to MRI (pacemaker, metal implants, or certain types of heart valves),
  • pregnant patients, minors, mentally disabled patients and prisoners will be excluded from this study. (All criteria apply to patients and normal volunteers).
  • Gadolinium nephrotoxicity will be addressed by having patients with abnormal kidney function (GFR<30) excluded from the study due to the (very small) risk associated with gadolinium contrast agents. This threshold may be modified, depending on practices determined by the Radiology Department and the IRB.
  • Patients with a known allergy or contraindication to Adenosine and/or Regadenoson will be excluded from stress (hyperemia) cohorts.
  • All participants that will receive a stress agent will refrain from consuming caffeine for at least 12 hours prior to each study