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Magnetic Resonance Imaging
systems
are able to generate high quality diagnostic images through
the use of a powerful magnetic field. |
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Hydrogen protons within the body align with the magnetic
field. By applying short radio frequency (RF)
pulses to a specific anatomical slice, the protons in
the slice absorb energy at the resonant frequency
causing them to spin perpendicular to the magnetic
field. |
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As the protons relax back into alignment with the
magnetic field, a signal is received by a RF coil that
acts as an antennae. This signal is processed by a
computer to produce diagnostic images of the anatomical
area of interest. Depending on the type of RF
pulse sequence used, either T1 or T2 weighted images are
generated. These contiguous thin slice images can
be obtained in various planes for optimum clinical
evaluation. |
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MRI offers the best of all imaging modalities because
of its superior contrast differentiation between
muscle, fat, vessels, tendons, ligaments, cartilage,
cortical bone and marrow bone space. MRI also
displays excellent delineation of tumors of soft
tissue and bone as well as vascular necrosis of bone.
High resolution knee imaging techniques provide
unparalleled detail of the menisci and ligaments.
MR imaging is very well suited for shoulder evaluation
of ligaments and tears of the rotator cuff, as well as
dislocation, without the need of invasive procedures
using injected contrast agents. MRI demonstrates
similar advantages in imaging other complex anatomy
such as the elbow, wrist, foot and ankle due to its
multi-planar capability and sensitivity to soft tissue
and bone disease processes and fractures. |
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Chest anatomy inherently offers contrast well suited
for MR imaging from structures such as fat, muscle,
lung, and flowing blood. Cardiac gating
techniques provide motion-free imaging for diagnosis
of vascular as well as non-vascular pathology by
capturing the images at the same point throughout
the cardiac cycle. A variation of this
technique enables cardiac structures to be acquired
in a cine format for evaluation of the dynamics of
blood flow, cardiac valves, and cardiac wall motion.
Dual-angle oblique capabilities along with pulse
sequences designed to accentuate flowing blood allow
imaging of the cardiac chambers in the long and
short axis. MRI is also beneficial for
evaluation of the thymus and disease processes of
the thoracic inlet due to the lack of bone artifacts
typically associated with CT imaging. |
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- Spine: |
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MRI of the spine has long been the procedure recognized as
yielding the most diagnostic information for the
evaluation of primary or metastatic tumors of the spinal
cord. MR imaging of other important anatomical
structures of the spinal cord such as the nerve and nerve
roots, neural foramina, ligament, and disc spaces is
further enhanced by exceptional resolution and contrast
without bone artifacts which are common in CT spinal
imaging. Using orthogonal and oblique slice planes,
along with various selections of tissue contrast, MR
provides a highly effective alternative to myelography and
the risks associated with intra-thecal contrast
injections. It is also useful in the post-operative
patient to distinguish between scar and recurrent disc
disease. |
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- Abdomen/Pelvis: |
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MRI of the liver offers unmatched sensitivity to pathology
compared to CT in the detection of primary and
metastatic liver tumors. Abdominal MR, which
historically was very sensitive to motion, has
been radically improved with recent software and
hardware innovations which provide faster imaging
techniques. This allows image acquisition
within a single breath hold. MRI also
provides the capability to perform high resolution
imaging of the adrenals, kidneys, pancreas and
spleen for diagnosis of tumors, infections and
vascular anomalies. MRI of the pelvis and
genitourinary system offers the advantages of
improved soft tissue discrimination and absence of
bone artifacts. Also, without the use of
ionizing radiation, MRI provides for safe imaging
of the reproductive region of adults as well as
children. |
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- Facial/Neck: |
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The superb soft tissue detail consistently
demonstrated by MR imaging allows for enhanced
evaluation of facial and neck structures.
Pre-surgical and pre-radiation treatment planning and
follow-up are enhanced by MRI's ability to delineate
anatomical boundaries. In addition, it's easy to
determine both size and extension of lesions in the
facial and neck area. MRI also excels in the
ability to determine vascular from non-vascular
anatomy without risk associated with iodinated
contrast agent use. |
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