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From ISOL Technology
'Ultra high field MR system, it's right close to you.
FORTE 3.0T is the new standard for the future ultra high field MR system.
If you are pushing the limits of your existing clinical MR scanner, the FORTE will surely take you to the next level of diagnostic imaging.
FORTE is the core leader of the medical technology in the 21st century. Proving effects of fMRI that cannot be measured with MRI less than 2.0T.'
Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
Short bore compact
128 x 128, 256 x 256, 512 x 512, 1024 x 1024
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Fat suppression is the process of utilizing specific MRI parameters to remove the deleterious effects of fat from the resulting images , e.g. with STIR, FAT SAT sequences, water selective (PROSET WATS - water only selection, also FATS - fat only selection possible) excitation techniques, or pulse sequences based on the Dixon method.
Spin magnetization can be modulated by using special RF pulses. CHESS or its variations like SPIR, SPAIR ( Spectral Selection Attenuated Inversion Recovery) and FAT SAT use frequency selective excitation pulses, which produce fat saturation.
Fat suppression techniques are nearly used in all body parts and belong to every standard MRI protocol of joints like knee, shoulder, hips, etc.
Image Guidance
Imaging of, e.g. the foot can induce bad fat suppression with SPIR/FAT SAT due to the asymmetric volume of this body part. The volume of the foot alters the magnetic field to a different degree than the smaller volume of the lower leg affecting the protons there. There is only a small band of tissue where the fat protons are precessing at the frequency expected, resulting in frequency selective fat saturation working only in that area. This can be corrected by volume shimming or creating a more symmetrical volume being imaged with water bags.
Even with their longer scan time and motion sensitivity, STIR (short T1/tau inversion recovery) sequences are often the better choice to suppress fat. STIR images are also preferred because of the decreased sensitivity to field inhomogeneities, permitting larger fields of views when compared to fat suppressed images and the ability to image away from the isocenter. See also Knee MRI.
Sequences based on Dixon turbo spin echo ( fast spin echo) can deliver a significant better fat suppression than conventional TSE/FSE imaging.
| | | | | | • View the DATABASE results for 'Fat Suppression' (28).
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Short name: AMI-25, generic name: Ferumoxide (SPIO)
Ferumoxides are superparamagnetic ( T2*) MRI contrast agents, so the largest signal change is on T2 and T2* weighted images. The agent distributes relatively rapidly to organs with reticuloendothelial cells primarily the liver, spleen and bone marrow.
The liver shows decreased signal intensity, as does the spleen and marrow. The agent is taken up by the normal liver, resulting in increased CNR between tumor and normal liver. Hepatocellular lesions, such as adenoma or focal nodular hyperplasia, contain reticuloendothelial cells, so they will behave similar to the liver, with decreased signal on T2 weighted images. On T1 images, there is typically some circulating contrast agent, and blood vessels show increased signal intensity.
Current MRI protocols involve T1 weighted breath-hold gradient echo images of the liver, and fast spin echo T2 weighted pictures. This requires about 15 minutes. The patient is then removed from the scanner, and the contrast agent administered. After contrast administration, the same pulse sequences are again repeated. | | | | • View the DATABASE results for 'Ferumoxide' (5).
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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. | | | | | | • View the DATABASE results for 'Flow' (113).
| | | • View the NEWS results for 'Flow' (7).
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| | | | • View the DATABASE results for 'Flow Compensation' (14).
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