
MR Angiogram of the descending aorta, kidneys and renal arteries |
The evolution of MR angiography (MRA),
CT angiography (CTA), and ultrasound angiography techniques have been significant
developments, and they are replacing x-ray angiography as
the preferred diagnostic tool for the detection of plaques and blockages (stenoses) in the
blood vessels. This is due to the fact that conventional angiography is more invasive,
significantly more time consuming, more expensive than MRA, CTA and ultrasound
angiography. Thus, conventional angiography is being increasingly used only as a
therapeutic tool to aid, for instance, in angioplasty procedures, which are helpful in
removing plaque obstructions in the neck vessels or for opening clogged coronary arteries.
MR is also developing a tremendous
potential for not only showing the structure or anatomy of the body, but also the function
or workings of the body. For instance, some leading MR companies have commercially
available systems (with echo Planar Imaging or EPI capabilities) that can show brain
function, thus making the early detection of deadly stroke more
possible. Functional MR (f-MR) can be used to even glimpse at the neural activity of the
brain itself, for example, during pattern recognition study. f-MR can also show the
function of the cardiac muscle (myocardium). Other MR procedures can depict the coronary
vessels or create movie-like scenes of the beating heart. While these functional studies
are not yet commonplace, even at many large university medical centers, use of these
functional studies and their promising benefits may proliferate in the coming years as
they become easier and less expensive to perform.
New,
Patient Friendly MR System Designs

A mother reads to her daughter during an Open MR examination |
MRI, like CT, requires the patient to
lie still on a special table inside the scanning gantry for ten to thirty minutes.
However, during the conventional "high-field" MR exam, patients must lie
completely still for shorter durations of five t o ten minutes at a time. The CT exam may
only require patient cooperation for a few seconds to a few minutes at a time. Due to the
longer examination times of MR and the closed nature of the cylindrical magnet used in
traditional "high-field" MR equipment (0.5 to 1.5 Tesla magnetic field
strength), some patients who undergo MR may experience claustrophobic anxiety.

The MR technologist consoles a senior prior to an MR examination on a new "short bore
system" |
Technical innovation is bringing new,
"friendlier" MR designs like "open MR" and "short-bore MR",
into routine clinical use. The new "open" or "C-shaped" MR systems
(0.2 to 0.3 Tesla field strength) are typically open on all sides and improve a person's
MR experience by lessening claustrophobia. Also becoming available are new versions of
conventional "high-field" (cylindrical) MR systems with shorter magnets and more
patient friendly (wider and shorter) aperture designs. These new "short-bore"
systems promise to also further minimize patient anxiety about MR examination.
Updated: June 10, 2008
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