A Magnetic Resonance Angiography (MRA) is a specialized type of Magnetic Resonance Imaging (MRI) used to visualize the body’s blood vessels. This non-invasive procedure uses a strong magnetic field and radio waves to create detailed images of arteries and veins, often checking for blockages, narrowing (stenosis), or aneurysms. The total experience is longer than the scan itself, so understanding the time commitment is important for planning.
How Long Does the Scan Actually Take?
The duration of the actual MRA scan—the time spent inside the magnetic bore—typically ranges from 15 to 60 minutes. A simpler non-contrast MRA of a smaller area, such as the brain, may take as little as 10 to 15 minutes. Scans requiring more detail or covering multiple vascular beds, like the arteries in both legs, will take substantially longer.
The total imaging time is divided into numerous small segments, known as sequences, each capturing specific image data. These individual sequences are often short, lasting from a few seconds to several minutes. The complexity and number of required sequences directly impact the final scan time. For example, a Time-of-Flight (TOF) MRA, a common technique for imaging brain arteries, relies on flowing blood to create contrast and is a relatively quick acquisition. If the MRA is performed in conjunction with a standard MRI of the surrounding tissue, the total time inside the machine can easily extend beyond 60 minutes.
Accounting for the Total Appointment Time
Patients should budget significantly more time than the scan duration for the entire MRA appointment, generally between 60 to 90 minutes from arrival to departure. The process begins with check-in and paperwork, followed by changing into a metal-free gown. A thorough pre-scan screening is performed to confirm there are no metal implants or foreign bodies that could interfere with the magnet.
If the MRA requires the injection of a contrast agent like Gadolinium, a technologist will need to place an intravenous (IV) line. Once positioned on the scanning table, the technologist must carefully set up the imaging coils and align the body part within the machine, which takes several minutes before the first image is acquired. After the imaging is complete and the IV is removed, there may be a short period of monitoring before the patient is cleared to leave.
Factors That Can Extend the Procedure
Several circumstances can cause an MRA procedure to take longer than the standard time estimates.
Contrast Agent Use
The decision to use a contrast agent adds time because it requires the placement of an IV line and careful timing of the injection during the scan sequence to capture the dye as it flows through the vessels.
Imaging Multiple Areas
Imaging multiple areas, such as the neck and the head, requires the technologist to move and re-position the imaging coils and adjust the scan protocol, significantly increasing the total time inside the bore.
Patient Movement and Comfort
Patient cooperation is also a variable, as any involuntary movement during image acquisition can blur the pictures, necessitating a repeat of that specific sequence. If a patient experiences discomfort or anxiety, the technologist may need to pause the scan to provide reassurance or wait for the patient to settle, which adds minutes to the procedure.
Technical Complexity
Technical complexity, such as performing a specialized multi-phase acquisition to track blood flow over time, requires a more intricate setup and a longer overall scan protocol.