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Image Quality
The quality of magnetic resonance imaging is particularly dependent on image resolution (matrix, field of view, slice thickness), contrast (TE, TR), signal to noise ratio (bandwidth, signal averaging) and lack of artifacts. These MRI parameters are affected by the field homogeneity, the field strength, the coil, the pulse sequence type and imaging techniques like parallel imaging.
See also Image Contrast Characteristics.
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• Related Searches:
    • Field Homogeneity
    • High Field MRI
    • Liver Imaging
    • MRI Procedure
    • Cervical Spine MRI
Further Reading:
Guidelines for Developing Automated Quality Control Procedures for Brain Magnetic Resonance Images Acquired in Multi-Centre Clinical Trials
Tuesday, 26 April 2011   by    
Image Characteristics and Quality
  News & More:
Patient movement during MRI: Additional points to ponder
Tuesday, 5 January 2016   by    
Novel Imaging Technique Improves Prostate Cancer Detection
Tuesday, 6 January 2015   by    
NanoMRI could image single biomolecules
Monday, 29 December 2014   by    
Breast MRI more widely used now that equipment, images are better
Sunday, 21 October 2012   by    
Searchterm 'Image Quality' was also found in the following services: 
Radiology  (13) Open this link in a new windowUltrasound  (35) Open this link in a new windowMarket  (1) Open this link in a new window
Open MRIForum -
related threads
Open MRI scanners have been developed for people who are anxious or obese or for examination of small parts of the body, such as the extremities (knee, shoulder). In addition, some systems offer imaging in different positions and sequences of movements. The basic technology of an open MRI machine is similar to that of a traditional MRI device. The major difference for the patient is that instead of lying in a narrow tunnel, the imaging table has more space around the body so that the magnet does not completely surround the person being tested.
Types of constructions:
Semi open high field MRI scanners provide an ultra short bore (tunnel) and widely flared ends. In this type of MRI systems, patients lie with the head in the space outside the bore, if for example the hips are examined.
Open low field MRI machines have often a wide open design, e.g. an open C-arm scanner is shaped like two large discs separated by a large pillar. Patients have an open sided feeling and more space around them allows a wider range of positions.
Advanced open MRI scanners combine the advantages of both, the high field strength, newest gradient technology and wide open design. Even scans of patients in upright, weight-bearing positions are possible (e.g. Upright™ MRI formerly Stand-Up MRI).

Difficulties with a traditional MRI scan include claustrophobia and patient size or, for health related reasons, patients who are not able to receive this type of diagnostic test. The MRI unit is a limited space, and some patients may be too large to fit in a narrow tunnel. In addition, weight limits can restrict the use of some scanners. The open MRI magnet has become the best option for those patients.
All of the highest resolution MRI scanners are tunnels and tend to accentuate the claustrophobic reaction. While patients may find the open MRI scanners easier to tolerate, some machines use a lower field magnet and generates lower image quality or have longer scan time. The better performance of an advanced open MRI scanner allows good image quality caused by the higher signal to noise ratio with maximum patient comfort.
See also Claustrophobia, MRI scan and Knee MRI.

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MRI Resources 
Jobs - Spine MRI - Stimulator pool - Liver Imaging - Functional MRI - Knee MRI
Sensitivity EncodingInfoSheet: - Sequences - 
Types of, 
(SENSE™) A MRI technique for relevant scan time reduction. The spatial information related to the coils of a receiver array are utilized for reducing conventional Fourier encoding. In principle, SENSE can be applied to any imaging sequence and k-space trajectories. However, it is particularly feasible for Cartesian sampling schemes. In 2D Fourier imaging with common Cartesian sampling of k-space sensitivity encoding by means of a receiver array enables to reduce the number of Fourier encoding steps.
SENSE reconstruction without artifacts relies on accurate knowledge of the individual coil sensitivities. For sensitivity assessment, low-resolution, fully Fourier-encoded reference images are required, obtained with each array element and with a body coil.
The major negative point of parallel imaging techniques is that they diminish SNR in proportion to the numbers of reduction factors. R is the factor by which the number of k-space samples is reduced. In standard Fourier imaging reducing the sampling density results in the reduction of the FOV, causing aliasing. In fact, SENSE reconstruction in the Cartesian case is efficiently performed by first creating one such aliased image for each array element using discrete Fourier transformation (DFT).
The next step then is to create a full-FOV image from the set of intermediate images. To achieve this one must undo the signal superposition underlying the fold-over effect. That is, for each pixel in the reduced FOV the signal contributions from a number of positions in the full FOV need to be separated. These positions form a Cartesian grid corresponding to the size of the reduced FOV.
The advantages are especially true for contrast-enhanced MR imaging such as dynamic liver MRI (liver imaging) , 3 dimensional magnetic resonance angiography (3D MRA), and magnetic resonance cholangiopancreaticography (MRCP).
The excellent scan speed of SENSE allows for acquisition of two separate sets of hepatic MR images within the time regarded as the hepatic arterial-phase (double arterial-phase technique) as well as that of multidetector CT.
SENSE can also increase the time efficiency of spatial signal encoding in 3D MRA. With SENSE, even ultrafast (sub second) 4D MRA can be realized.
For MRCP acquisition, high-resolution 3D MRCP images can be constantly provided by SENSE. This is because SENSE resolves the presence of the severe motion artifacts due to longer acquisition time. Longer acquisition time, which results in diminishing image quality, is the greatest problem for 3D MRCP imaging.
In addition, SENSE reduces the train of gradient echoes in combination with a faster k-space traversal per unit time, thereby dramatically improving the image quality of single shot echo planar imaging (i.e. T2 weighted, diffusion weighted imaging).

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Further Reading:
  News & More:
Image Characteristics and Quality
Searchterm 'Image Quality' was also found in the following services: 
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AIRIS II™InfoSheet: - Devices -
Types of Magnets, 
etc.MRI Resource Directory:
 - Devices -

From Hitachi Medical Systems America Inc.;
the AIRIS II, an entry in the diagnostic category of open MR systems, was designed by Hitachi Medical Systems America Inc. (Twinsburg, OH, USA) and Hitachi Medical Corp. (Tokyo) and is manufactured by the Tokyo branch. A 0.3 T field-strength magnet and phased array coils deliver high image quality without the need for a tunnel-type high-field system, thereby significantly improving patient comfort not only for claustrophobic patients.

Device Information and Specification
CONFIGURATION Vertical Field, Open MRI
SURFACE COILS QD Head, MA Head and Neck, QD C-Spine, MA or QD Shoulder, MA CTL Spine, QD Knee, Neck, QD TMJ, QD Breast, QD Flex Body (4 sizes), Small and Large Extrem., QD Wrist, MA Foot and Ankle (WIP), PVA (WIP)
SYNCHRONIZATION Cardiac gating, ECG/peripheral, respiratory gating (2 modes)
IMAGING MODES Single, multislice, volume study
TR SE: 30 - 10,000msec GE: 20 - 10,000msec IR: 50 - 16,700msec FSE: 200 - 16,7000msec
TE SE : 10 - 250msec IR: 10 -250msec GE: 5 - 50 msec FSE: 15 - 2,000
SINGLE/MULTI SLICE 0.05 sec/image (256 x 256)
FOV 5cm to 42 cm continuous
SLICE THICKNESS 2D: 2 - 100 mm; 3D: 0.5 - 5 mm
DISPLAY MATRIX 1280 x 1024
PIXEL INTENSITY Level Range: -2,000 to +4,000
MAGNET TYPE Self-shielded, permanent
or W x H
110 x 43 cm
H*W*D 79 x 111 x 73 cm
POWER REQUIREMENTS 208/220/240 V, single phase
5 GAUSS FRINGE FIELD 2.0 m lateral, 2.5 m vert./long
SHIMMING Auto shimming, 3-axis/patient, and volume shim


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Searchterm 'Image Quality' was also found in the following services: 
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Abdominal ImagingMRI Resource Directory:
 - Abdominal Imaging -
General MRI of the abdomen can consist of T1 or T2 weighted spin echo, fast spin echo (FSE, TSE) or gradient echo sequences with fat suppression and contrast enhanced MRI techniques. The examined organs include liver, pancreas, spleen, kidneys, adrenals as well as parts of the stomach and intestine (see also gastrointestinal imaging). Respiratory compensation and breath hold imaging is mandatory for a good image quality.
T1 weighted sequences are more sensitive for lesion detection than T2 weighted sequences at 0.5 T, while higher field strengths (greater than 1.0 T), T2 weighted and spoiled gradient echo sequences are used for focal lesion detection. Gradient echo in phase T1 breath hold can be performed as a dynamic series with the ability to visualize the blood distribution. Phases of contrast enhancement include the capillary or arterial dominant phase for demonstrating hypervascular lesions, in liver imaging the portal venous phase demonstrates the maximum difference between the liver and hypovascular lesions, while the equilibrium phase demonstrates interstitial disbursement for edematous and malignant tissues.
Out of phase gradient echo imaging for the abdomen is a lipid-type tissue sensitive sequence and is useful for the visualization of focal hepatic lesions, fatty liver (see also Dixon), hemochromatosis, adrenal lesions and renal masses. The standards for abdominal MRI vary according to clinical sites based on sequence availability and MRI equipment. Specific abdominal imaging coils and liver-specific contrast agents targeted to the healthy liver tissue improve the detection and localization of lesions.
See also Hepatobiliary Contrast Agents, Reticuloendothelial Contrast Agents, and Oral Contrast Agents.

For Ultrasound Imaging (USI) see Abdominal Ultrasound at
Images, Movies, Sliders:
 MR Colonography Gadolinium per Rectum  Open this link in a new window

Courtesy of  Robert R. Edelman
 Anatomic Imaging of the Liver  Open this link in a new window

 CE MRA of the Aorta  Open this link in a new window
SlidersSliders Overview


• View the DATABASE results for 'Abdominal Imaging' (11).Open this link in a new window

• View the NEWS results for 'Abdominal Imaging' (3).Open this link in a new window.
Further Reading:
Abdominal MRI at 3.0 T: The Basics Revisited
Wednesday, 20 July 2005   by    
Usefulness of MR Imaging for Diseases of the Small Intestine: Comparison with CT
2000   by    
  News & More:
RSI-MRI imaging technology can effectively differentiate aggressive prostate cancer
Thursday, 2 June 2016   by    
Computer-aided detection and diagnosis for prostate cancer based on mono and multi-parametric MRI: A review - Abstract
Tuesday, 28 April 2015   by    
MRI for differentiating ovarian endometrioid adenocarcinoma from high-grade serous adenocarcinoma
Wednesday, 29 April 2015   by    
MRI identifies 'hidden' fat that puts adolescents at risk for disease
Tuesday, 27 February 2007   by    
Nottingham scientists exploit MRI technology to assist in the treatment of IBS
Thursday, 9 January 2014   by    
New MR sequence helps radiologists more accurately evaluate abnormalities of the uterus and ovaries
Thursday, 23 April 2009   by    
MRI Resources 
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