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Result : Searchterm 'Image Quality' found in 1 term [] and 44 definitions []
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News  (17)  Resources  (5)  Forum  (10)  
 
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:
    • Image Contrast Characteristics
    • Resolution
    • Matrix
    • MRI Procedure
    • Lung Imaging
 
Further Reading:
  Basics:
Image Characteristics and Quality
   by www.sprawls.org    
  News & More:
Impact of Magnetic Field Inhomogeneity on the Quality of Magnetic Resonance Images and Compensation Techniques: A Review
Saturday, 1 October 2022   by www.dovepress.com    
Researchers design 'intelligent' metamaterial to make MRIs affordable and accessible
Tuesday, 5 November 2019   by phys.org    
Patient movement during MRI: Additional points to ponder
Tuesday, 5 January 2016   by www.healthimaging.com    
Novel Imaging Technique Improves Prostate Cancer Detection
Tuesday, 6 January 2015   by health.ucsd.edu    
Searchterm 'Image Quality' was also found in the following services: 
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Radiology  (13) Open this link in a new windowUltrasound  (35) 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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• View the DATABASE results for 'Open MRI' (37).Open this link in a new window


• View the NEWS results for 'Open MRI' (16).Open this link in a new window.
 
Further Reading:
  Basics:
Open MRI scanners reduce anxiety in patients
Thursday, 8 September 2011   by www.mtbeurope.info    
  News & More:
Safety of Bedside Portable Low-Field Brain MRI in ECMO Patients Supported on Intra-Aortic Balloon Pump
Friday, 18 November 2022   by www.mdpi.com    
Esaote Obtains EC MDR Certification for the New Magnifico Open Total-body Magnetic Resonance System
Sunday, 5 December 2021   by www.itnonline.com    
World's First Portable MRI Cleared by FDA
Monday, 17 February 2020   by www.medgadget.com    
How Much Does an Open MRI Cost?
Tuesday, 1 January 2019   by health.costhelper.com    
Radiographer's Lego Open MRI Product Idea Reaches New Milestone
Monday, 11 November 2019   by www.itnonline.com    
MRI Resources 
Implant and Prosthesis pool - Cochlear Implant - Health - Contrast Agents - Non-English - Movies
 
Sensitivity EncodingInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
(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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• View the DATABASE results for 'Sensitivity Encoding' (12).Open this link in a new window

 
Further Reading:
  News & More:
Image Characteristics and Quality
   by www.sprawls.org    
Searchterm 'Image Quality' was also found in the following services: 
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News  (17)  Resources  (5)  Forum  (10)  
 
AIRIS II™InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.hitachimed.com/products/airis_2.asp 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
CLINICAL APPLICATION
Whole body
CONFIGURATION
Vertical Field, Open MRI
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)
PULSE SEQUENCES
SE, GE, GR, IR, FIR, STIR, FSE, ss-FSE, FLAIR, EPI -DWI, SE-EPI, ms - EPI, SSP, MTC, SARGE, RSSG, TRSG, MRCP, Angiography: CE, 2D/3D TOF
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
2D: 2 - 100 mm; 3D: 0.5 - 5 mm
1280 x 1024
MEASURING MATRIX
512 x 512
PIXEL INTENSITY
Level Range: -2,000 to +4,000
Sub millimeter
MAGNET TYPE
Self-shielded, permanent
BORE DIAMETER
or W x H
110 x 43 cm
MAGNET WEIGHT
15,700 kg
H*W*D
79 x 111 x 73 cm
POWER REQUIREMENTS
208/220/240 V, single phase
COOLING SYSTEM TYPE
Air-cooled
STRENGTH
15 mT/m
2.0 m lateral, 2.5 m vert./long
Auto shimming, 3-axis/patient, and volume shim
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• View the DATABASE results for 'AIRIS II™' (2).Open this link in a new window

Searchterm 'Image Quality' was also found in the following services: 
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Radiology  (13) Open this link in a new windowUltrasound  (35) Open this link in a new window
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 Medical-Ultrasound-Imaging.com.
 
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

 
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• 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:
  Basics:
Abbreviated MRI Protocols for the Abdomen
Friday, 22 March 2019   by pubs.rsna.org    
Abdominal MRI at 3.0 T: The Basics Revisited
Wednesday, 20 July 2005   by www.ajronline.org    
Usefulness of MR Imaging for Diseases of the Small Intestine: Comparison with CT
2000   by www.ncbi.nlm.nih.gov    
  News & More:
Assessment of Female Pelvic Pathologies: A Cross-Sectional Study Among Patients Undergoing Magnetic Resonance Imaging for Pelvic Assessment at the Maternity and Children Hospital, Qassim Region, Saudi Arabia
Saturday, 7 October 2023   by www.cureus.com    
Higher Visceral, Subcutaneous Fat Levels Predict Brain Volume Loss in Midlife
Wednesday, 4 October 2023   by www.neurologyadvisor.com    
Deep Learning Helps Provide Accurate Kidney Volume Measurements
Tuesday, 27 September 2022   by www.rsna.org    
CT, MRI for pediatric pancreatitis interobserver agreement with INSPPIRE
Friday, 11 March 2022   by www.eurekalert.org    
Clinical trial: Using MRI for prostate cancer diagnosis equals or beats current standard
Thursday, 4 February 2021   by www.eurekalert.org    
Computer-aided detection and diagnosis for prostate cancer based on mono and multi-parametric MRI: A review - Abstract
Tuesday, 28 April 2015   by urotoday.com    
Nottingham scientists exploit MRI technology to assist in the treatment of IBS
Thursday, 9 January 2014   by www.news-medical.net    
New MR sequence helps radiologists more accurately evaluate abnormalities of the uterus and ovaries
Thursday, 23 April 2009   by www.eurekalert.org    
MRI identifies 'hidden' fat that puts adolescents at risk for disease
Tuesday, 27 February 2007   by www.eurekalert.org    
MRI Resources 
Education pool - IR - Software - Hospitals - Implant and Prosthesis pool - Musculoskeletal and Joint MRI
 
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