Imaging Sequence Type:
- Saturation Recovery Prepared FSPGR (GE), FLASH (Siemens), T1 FFE (Philips), Field Echo (Toshiba)
- Images are typically generated over several heartbeats during a breathhold
Acquisition Mode: Multi slice, multiphase (i.e. cines at multiple slice locations showing first passage of a contrast bolus)
Image Contrast:
- Bright blood (following gadolinium contrast)
- T1-weighted
- Alternative sequences that are sometimes used include
- saturation recovery gradient-echo echo-planar imaging (EPI)
- saturation recovery steady state free precession (SSFP)
Imaging Options: Parallel imaging is usually employed to improve image temporal resolution and spatial coverage: ASSET (GE), iPAT (Siemens), SENSE (Philips), SPEEDER (Toshiba)
Clinical Utility:
- Perfusion imaging is usually performed during stress to assess for obstructive coronary artery disease.
- A perfusion defect is identified as a region of decreased myocardial signal during the first pass contrast bolus (“dark spots are bad”). In the case shown above, the patient has a severe stenosis of the mid LAD which causes diminished perfusion to the midventricular anteroseptum and the apex.
- The most common stress agents for MRI are vasodilators (e.g. adenosine or regadenoson)
- Stress perfusion imaging is usually combined with either rest perfusion imaging or late gadolinium enhancement (LGE) imaging to distinguish coronary insufficiency from myocardial scar.
- The patient is usually instructed to breath hold during image acquisition, although it is not absolutely essential.
