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| | | | | |  | Searchterm 'Pulse Sequence' was also found in the following services: | | | | |
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News & More:
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| | | Searchterm 'Pulse Sequence' was also found in the following service: | | | | |
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Flow phenomena are intrinsic processes in the human body. Organs like the heart, the brain or the kidneys need large amounts of blood and the blood flow varies depending on their degree of activity. Magnetic resonance imaging has a high sensitivity to flow and offers accurate, reproducible, and noninvasive methods for the quantification of flow. MRI flow measurements yield information of blood supply of of various vessels and tissues as well as cerebro spinal fluid movement.
Flow can be measured and visualized with different pulse sequences (e.g. phase contrast sequence, cine sequence, time of flight angiography) or contrast enhanced MRI methods (e.g. perfusion imaging, arterial spin labeling).
The blood volume per time (flow) is measured in: cm3/s or ml/min. The blood flow-velocity decreases gradually dependent on the vessel diameter, from approximately 50 cm per second in arteries with a diameter of around 6 mm like the carotids, to 0.3 cm per second in the small arterioles.
Different flow types in human body:
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Behaves like stationary tissue, the signal intensity depends on T1, T2 and PD = Stagnant flow |
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Flow with consistent velocities across a vessel = Laminar flow |
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Laminar flow passes through a stricture or stenosis (in the center fast flow, near the walls the flow spirals) = Vortex flow |
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Flow at different velocities that fluctuates = Turbulent flow |
See also Flow Effects, Flow Artifact, Flow Quantification, Flow Related Enhancement, Flow Encoding, Flow Void, Cerebro Spinal Fluid Pulsation Artifact, Cardiovascular Imaging and Cardiac MRI.
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• View the DATABASE results for 'Flow' (113).
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• View the NEWS results for 'Flow' (7).
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• View the DATABASE results for 'Fluid Attenuation Inversion Recovery' (5).
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| | | Searchterm 'Pulse Sequence' was also found in the following services: | | | | |
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From Esaote S.p.A.;
Esaote introduced the new G-SCAN at the RSNA in Dec. 2004. The G-SCAN covers almost all musculoskeletal applications including the spine. The tilting gantry is designed for scanning in weight-bearing positions. This unique MRI scanner is developed in line with the Esaote philosophy of creating high quality MRI systems that are easy to install and that have a low breakeven point.
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Device Information and Specification (Under Development) |
| CLINICAL APPLICATION |
Musculoskeletal, extremity |
| CONFIGURATION |
Open MRI |
| SURFACE COILS |
Spine, extremity, shoulder, flex coil, knee dual phased array, ankle//foot dual phased array, hand//wrist dual phased array |
| PULSE SEQUENCES |
SE, GE, IR, STIR, TSE, 3D CE, GE-STIR, 3D GE, ME, TME, HSE |
| IMAGING MODES |
Single, multislice, volume study, fast scan, multi slab, cine |
| FOV |
100 up to 350 mm, 25 mm displayed |
| DISPLAY MATRIX |
512 x 512 |
| MEASURING MATRIX |
256 x 256 maximum |
| MAGNET TYPE |
Permanent |
BORE DIAMETER
or W x H |
33 cm H, open |
| POWER REQUIREMENTS |
100/110/200/220/230/240 |
| FIELD STRENGTH |
0.25 T |
| STRENGTH |
25 mT/m |
| 5-GAUSS FRINGE FIELD, radial/axial |
180 cm |
| SHIMMING |
Passive |
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• View the DATABASE results for 'G-SCAN' (3).
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| | | Searchterm 'Pulse Sequence' was also found in the following service: | | | | |
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Quick Overview
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Artifact Information |
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Ghosting, ghost
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| DESCRIPTION |
Displaced reduplications of image in phase encoding direction
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Motion, heartbeat, respiration |
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Triggering, breath hold, pharmaceuticals to reduce bowel motion |
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Ghosting artifacts are in the most cases caused by movements (e.g., respiratory motion, bowel motion, arterial pulsations, swallowing, and heartbeat) and appear in the phase encoding direction.
Image Guidance
Ghosting artifacts can be reduced by respiratory and cardiac triggering, the use of breath holding pulse sequences, flow compensation or presaturation pulses, depending on their origin. To reduce bowel motion also pharmaceuticals, such as glucagon or scopolamine are useful. This will decrease artifacts from both peristalsis and breathing.
See also Motion Artifact, Phase Encoded Motion Artifact, Cardiac Motion Artifact, and Artifact Reduction - Motion. |
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• View the DATABASE results for 'Ghosting Artifact' (5).
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