Imaging of Plaque With Magnetic Resonance Imaging (MRI)

For those patients undergoing cardiac catheterization, an 8French sheath will be introduced
via a femoral artery approach. This size sheath allows us to visualize the distal aorta
while performing the intra vascular ultrasound ( IVUS). For these patients, if a femoral
venous sheath is also positioned for clinical purposes, then this access will also be
utilized to introduce the MRI coil. This imaging approach will allow us to compare the
feasibility of intravascular MRI imaging from: a) the artery; b) the vein; c) a combination
of both.

For those patients not scheduled to undergo a clinically indicated cardiac catheterization,
only a 6French sheath will be introduced via a femoral artery approach. In these patients,
no femoral venous sheath will be introduced and the arterial access will not be upsized to a
8French sheath.

Two tablespoons of blood will be drawn from each patient to assess inflammatory markers such
as C-Reactive Protein (CRP) as well as to confirm a negative pregnancy test for female
patients of childbearing age.

Using 20cc of non-ionic contrast, an angiogram of the distal aorta and the ilio-femoral
region will be performed and recorded on disc (5mins). Thereafter, an approved guidewire and
intravascular ultrasound catheter will be positioned in the same arteries via the same
access route, and ultrasound images of the arterial segment will be recorded (10mins.). The
guidewire and the ultrasound coil will then be removed. Finally, an intravascular MRI wire
will be advanced through the same arterial access and/or the previously indicated venous
access under X-ray control and positioned in the desired atherosclerotic segment in the
region of the distal aorta or at the ilio-femoral area. The MRI wire(s) will be secured in
place by Tegaderm and the femoral sheath(s) will be sutured in stable position. The patient
will then be transported to the MRI scanner, positioned in the scanner and images recorded
over a period not exceeding 60 minutes. During the transport and throughout the MRI
scanning, the patient will be monitored via an MRI-compatible cardiac monitor. During the
time that the intravascular MRI coil is within the femoral sheath, it will be continuously
perfused with heparinized saline and the patient will receive weight- adjusted (12 U/kg)
intravenous heparin for systemic anticoagulation to prevent thrombosis. To obtain the MRI
images, the patients will receive gadolinium contrast as per routine radiology protocols
(0.1-0.2 mmol/kg). After recording the MRI images, the MRI coil(s) and the femoral sheath(s)
will be removed from the artery and/or the vein as per usual care.

Inclusion Criteria:

- Male and female adults (aged 25-80) seen at the Brigham and Women's Hospital (BWH)
clinic who have known arterial disease who consent to cannulation of the femoral
artery for this research.

- Patients in the prespecified age group who are scheduled to undergo a clinically
indicated heart or peripheral catheterization at the BWH catheterization (cath) lab
who will have a tube (sheath) already positioned in their femoral artery

- Patient must be in stable condition with regard to symptoms, vital signs and the
monitored electrocardiogram

Exclusion Criteria:

- Unstable symptoms, vital signs or electrocardiogram after the heart cath

- Any complications during the heart cath (eg., bleeding, angina, arrhythmias,
technical difficulties cannulating the femoral artery)

- Creatinine >2.0mg/dl

- Pregnancy

- Contraindications to anticoagulation

- Patients with a metal implant, pacemaker, cardiac defibrillator, metal fragments in
the eye, bullets/metal objects in the body