Coil Sensitivity Encoding in MR Imaging
Advantages and Disadvantages in Clinical Practice
Yasuyuki Kurihara1,
Yoshiko K. Yakushiji1,
Ichiro Tani1,
Yasuo Nakajima1 and
Marc Van Cauteren2
1 Department of Radiology, St. Marianna University School of Medicine, 2-16-1
Sugao, Miyamae-Ku, Kawasaki City, Kanagawa, 216-8511, Japan.
2 Philips Medical Systems Corporation, Philips Bldg., 13-37 Kohnan 2-chome
Minato-Ku, Tokyo, 108, Japan.
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Fig. 1A. —Coil sensitivity encoding (SENSE) procedure in MR imaging.
Conventional Fourier transformation produces fewer phase encoding steps
(R factor, 2) and results in reduction of field of view, causing
typical foldover or aliasing artifact.
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Fig. 1B. —Coil sensitivity encoding (SENSE) procedure in MR imaging.
SENSE reconstruction algorithm separates superimposed signals using
information on individual coil sensitivities and restores full field-of-view
image. R factor = SENSE reduction factor.
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Fig. 2A. —49-year-old woman with ovarian cysts. T2-weighted sagittal
spin-echo MR image (TR/TE, 3500/1100) shows blurred bowel tract and muscle
(arrows) due to respiratory motion and bowel peristalsis. Scan time
for 15 slices was 1 min 35 sec.
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Fig. 2B. —49-year-old woman with ovarian cysts. T2-weighted sagittal
spin-echo MR image (3500/1100) using coil sensitivity encoding (R
factor, 2) shows anatomic structures (arrows) more clearly than
A because of suppression of motion artifact. Scan time for 15 slices
was 53 sec.
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Fig. 3A. —61-year-old woman with Takayasu's arteritis. High-resolution
contrast-enhanced MR angiography carotid images (TR/TE, 4.0/1.0) using
two-dimensional coil sensitivity encoding technique (R factor, 4)
provide high temporal-resolution dynamic study. Maximum-intensity-projection
angiograms from three-dimensional volumes are shown acquired at 8 (A),
12 (B), 16 (C), and 20 sec (D) after injection of
gadolinium-enhanced contrast agent. Field of view is 529 x 529 mm. Each
maximum-intensity-projection image is reconstructed with 24 slices of source
images.
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Fig. 3B. —61-year-old woman with Takayasu's arteritis. High-resolution
contrast-enhanced MR angiography carotid images (TR/TE, 4.0/1.0) using
two-dimensional coil sensitivity encoding technique (R factor, 4)
provide high temporal-resolution dynamic study. Maximum-intensity-projection
angiograms from three-dimensional volumes are shown acquired at 8 (A),
12 (B), 16 (C), and 20 sec (D) after injection of
gadolinium-enhanced contrast agent. Field of view is 529 x 529 mm. Each
maximum-intensity-projection image is reconstructed with 24 slices of source
images.
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Fig. 3C. —61-year-old woman with Takayasu's arteritis. High-resolution
contrast-enhanced MR angiography carotid images (TR/TE, 4.0/1.0) using
two-dimensional coil sensitivity encoding technique (R factor, 4)
provide high temporal-resolution dynamic study. Maximum-intensity-projection
angiograms from three-dimensional volumes are shown acquired at 8 (A),
12 (B), 16 (C), and 20 sec (D) after injection of
gadolinium-enhanced contrast agent. Field of view is 529 x 529 mm. Each
maximum-intensity-projection image is reconstructed with 24 slices of source
images.
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Fig. 3D. —61-year-old woman with Takayasu's arteritis. High-resolution
contrast-enhanced MR angiography carotid images (TR/TE, 4.0/1.0) using
two-dimensional coil sensitivity encoding technique (R factor, 4)
provide high temporal-resolution dynamic study. Maximum-intensity-projection
angiograms from three-dimensional volumes are shown acquired at 8 (A),
12 (B), 16 (C), and 20 sec (D) after injection of
gadolinium-enhanced contrast agent. Field of view is 529 x 529 mm. Each
maximum-intensity-projection image is reconstructed with 24 slices of source
images.
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Fig. 4. —35-year-old man with intralobar sequestration.
High-resolution pulmonary MR angiogram using two times longer TR (8 msec) and
coil sensitivity encoding (R factor, 2) shows perfusion defect in
left lower lobe due to intra-lobar sequestration. Note increased signals from
lung parenchyma because of longer T1 recovery.
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Fig. 5A. —49-year-old woman with cervical carcinoma of uterus.
T2-weighted sagittal spin-echo MR image (TR/TE, 3500/1100) shows decreased
signal intensity in marginal areas of field of view (arrows).
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Fig. 5B. —49-year-old woman with cervical carcinoma of uterus.
T2-weighted sagittal spin-echo MR image (3500/1100) using coil sensitivity
encoding (R factor, 2) shows uniform intensity of image
(arrows).
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Fig. 6A. —27-year-old healthy male volunteer. T2-weighted axial
spin-echo MR image (TR/TE, 3000/120; turbo factor, 13) results in strong fat
intensity with J-coupling effects.
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Fig. 6B. —27-year-old healthy male volunteer. Coil sensitivity encoding
image (R factor, 2) with same TR/TE as A, turbo factor of 7,
and longer echo spacing shows suppression of bright fat signal.
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Fig. 7. —71-year-old woman with adrenal mass. Abdominal gradient-echo
MR image (TR/TE, 215/2.3) using coil sensitivity encoding (SENSE) (R
factor, 2) shows residual bright fat signal (large arrow) and
"split-line" artifact (small arrows), which causes
jump-up intensity at mid portion. Both rare artifacts could be caused by
mismatch between reference scan and SENSE data acquisition.
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Fig. 8A. —45-year-old man with liver cirrhosis. Aliasing image before
coil sensitivity encoding (SENSE) reconstruction algorithm shows foldover
beyond midline of field of view because of small field-of-view setting.
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Fig. 8B. —45-year-old man with liver cirrhosis. SENSE reconstructed
images (TR/TE, 520/20; flip angle, 20°; R factor, 2) shows
remaining folded areas (arrows).
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