2. syngo GRAPPA
Powered by Tim
GRAPPA is a Siemens exclusive, k-space
based parallel imaging technique. GRAPPA
is important clinically because GRAPPA
can be applied through the entire body,
head-to-toe at smaller FoV’s without
artifacts. All Tim matrix coils, array coils
and various combinations of coil elements
are compatible with GRAPPA. Both 2D
and 3D scans can utilize GRAPPA to speed
acquisition and/or resolution.
Clinical Role
1. Higher Speed:
a) GRAPPA with Tim matrix coils
gives maximum freedom in
selecting the slice orientation
and acceleration factors.
b) Speed can be utilized to improve
temporal resolution in dynamic
studies and cardiac exams.
c) Reducing scan times and
breath-hold periods particularly
for uncooperative patients and
Figure 1: Primary sclerosing cholangitis. 2 min. 3D MRCP with iPAT factor 4.
Institute of Clinical Radiology, University Hospitals, Grosshadern, children can eliminate certain
Ludwig-Maximilians-University, Munich, Germany. movement artifacts (Figure 1).
2. Better resolution and anatomical
coverage:
a) The time saved with speed can be
utilized for high resolution scans
achieved in the same scan times
(Figures 2A–2C).
b) Alternatively, the anatomical
coverage (increase TR and # of
slices) can be increased keeping
the time the same.
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3. Figure 2A: 3D WE TrueFISP, GRAPPA 2. Figure 2B: Fat Sat, GRAPPA 2, 2:12, 3.5, 8 cm. Figure 2C: GRAPPA 2, 2:00, 2 mm, 9 cm.
Figure 3A: Without GRAPPA – more distortions. Figure 3B: With GRAPPA – less distortions.
3. Reduction of artifacts:
Figure 4:
a) Using GRAPPA permits MR GRAPPA 2, 3D Fat Sat
parameter changes like TE and VIBE, 120 slices in
bandwidth that help reduce 16 sec breath-hold,
susceptibility artifacts particularly 2 mm partitions.
for EPI based sequences. This is Courtesy of NYU,
MAGNETOM Avanto.
beneficial in the orbital, nasal sinus
and posterior fossa regions in the
brain.
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