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Result : Searchterm 'Image Quality' found in 1 term [] and 44 definitions []
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Searchterm 'Image Quality' was also found in the following services: 
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News  (17)  Resources  (5)  Forum  (10)  
 
Field of View
 
(FOV) Defined as the size of the two or three dimensional spatial encoding area of the image. Usually defined in units of mm². The FOV is the square image area that contains the object of interest to be measured. The smaller the FOV, the higher the resolution and the smaller the voxel size but the lower the measured signal. Useful for decreasing the scantime is a field of view different in the frequency and phase encoding directions (rectangular field of view - RFOV).
The magnetic field homogeneity decreases as more tissue is imaged (greater FOV). As a result the precessional frequencies change across the imaging volume. That can be a problem for fat suppression imaging. This fat is precessing at the expected frequency only in the center of the imaging volume. E.g. frequency specific fat saturation pulses become less effective when the field of view is increased. It is best to use smaller field of views when applying fat saturation pulses.
mri safety guidance
Image Guidance
Smaller FOV required higher gradient strength and concludes low signal. Therefore you have to find a compromise between these factors. The right choice of the field of view is important for MR image quality. When utilizing small field of views and scanning at a distance from the isocenter (more problems with artifacts) it is obviously important to ensure that the region of interest is within the scanning volume.
A smaller FOV in one direction is available with the function rectangular field of view (RFOV).

See also Field Inhomogeneity Artifact.
 
Images, Movies, Sliders:
 MRI - Anatomic Imaging of the Foot  Open this link in a new window
    
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 MRI - Anatomic Imaging of the Ankle 1  Open this link in a new window
    
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• Related Searches:
    • Frequency Encoding Gradient
    • Device
    • Signal to Noise Ratio
    • Coil Diameter
    • Phase Encoding Gradient
 
Further Reading:
  Basics:
Image Characteristics and Quality
   by www.sprawls.org    
  News & More:
Optimizing Musculoskeletal MR
   by rad.usuhs.mil    
Path Found to a Combined MRI and CT Scanner
Wednesday, 20 March 2013   by spectrum.ieee.org    
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
Filling Factor
 
A measure of the geometrical relationship of the RF coil and the object being studied. It affects the efficiency of exciting the object and detecting MR signals, thereby affecting the signal to noise ratio and image quality. Achieving a high filling factor requires fitting the coil closely to the object, thus potentially decreasing patient comfort.
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Further Reading:
  News & More:
Magnetic resonance-guided motorized transcranial ultrasound system for blood-brain barrier permeabilization along arbitrary trajectories in rodents
Thursday, 24 December 2015   by www.ncbi.nlm.nih.gov    
MRI Resources 
Liver Imaging - Claustrophobia - Knee MRI - MRI Training Courses - Brain MRI - Safety Training
 
High Field MRI
 
The principal advantage of MRI at high field is the increase in signal to noise ratio. This can be used to improve anatomic and/or temporal resolution and reduce scan time while preserving image quality. MRI devices for whole body imaging for human use are available up to 3 tesla (3T). Functional MRI (fMRI) and MR spectroscopy (MRS) benefit significantly. In addition, 3T machines have a great utility in applications such as TOF MRA and DTI. Higher field strengths are used for imaging of small parts of the body or scientific animal experiments. Higher contrast may permit reduction of gadolinium doses and, in some cases, earlier detection of disease.
Using high field MRI//MRS, the RF-wavelength and the dimension of the human body complicating the development of MR coils. The absorption of RF power causes heating of the tissue. The energy deposited in the patient's tissues is fourfold higher at 3T than at 1.5T. The specific absorption rate (SAR) induced temperature changes of the human body are the most important safety issue of high field MRI//MRS.
Susceptibility and chemical shift dispersion increase like T1, therefore high field MRI occasionally exhibits imaging artifacts. Most are obvious and easily recognized but some are subtle and mimic diseases. A thorough understanding of these artifacts is important to avoid potential pitfalls. Some imaging techniques or procedures can be utilized to remove or identify artifacts.

See also Diffusion Tensor Imaging.

See also the related poll result: 'In 2010 your scanner will probably work with a field strength of'
Medical-Ultrasound-Imaging.comMagnetic Resonance Guided Focused Ultrasound,  High Intensity Focused Ultrasound
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• View the DATABASE results for 'High Field MRI' (16).Open this link in a new window


• View the NEWS results for 'High Field MRI' (9).Open this link in a new window.
 
Further Reading:
  Basics:
Next-generation 7 T scanner ramps the resolution of brain MR imaging
Wednesday, 17 January 2024   by physicsworld.com    
A paired dataset of T1- and T2-weighted MRI at 3 Tesla and 7 Tesla
Thursday, 27 July 2023   by www.nature.com    
CLINICAL WHOLE BODY MRI AT 3.0 T(.pdf)
2001
Musculoskeletal MRI at 3.0 T: Relaxation Times and Image Contrast
Sunday, 1 August 2004   by www.ajronline.org    
  News & More:
How safe is 7T MRI for patients with neurosurgical implants?
Thursday, 17 November 2022   by healthimaging.com    
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    
7-T clinical MRI of the shoulder in patients with suspected lesions of the rotator cuff
Friday, 7 February 2020   by eurradiolexp.springeropen.com    
A 100-hour MRI scan captured the most detailed look yet at a whole human brain
Monday, 8 July 2019   by www.sciencenews.or    
T2-Weighted Liver MRI Using the MultiVane Technique at 3T: Comparison with Conventional T2-Weighted MRI
Friday, 16 October 2015   by www.ncbi.nlm.nih.gov    
Ultra-high-field MRI reveals language centres in the brain in much more detail
Tuesday, 28 October 2014   by medicalxpress.com    
Turbo-FLASH Based Arterial Spin Labeled Perfusion MRI at 7 T
Thursday, 20 June 2013   by www.plosone.org    
High-Resolution, Spin-Echo BOLD, and CBF fMRI at 4 and 7 T(.pdf)
October 2002   by otg.downstate.edu    
Vascular Filters of Functional MRI: Spatial Localization Using BOLD and CBV Contrast
Searchterm 'Image Quality' was also found in the following services: 
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News  (17)  Resources  (5)  Forum  (10)  
 
Image Resolution
 
The image resolution is the level of detail of an image and a measurement of image quality. Higher resolution means more image detail, for example when two structures 1 mm apart are distinguishable in an image, this picture has a higher resolution than an image where they are not to distinguish.
More data points in an MR image (with same FOV) will decrease the pixel size, but not accurately improve the resolution because the different MRI sequences influence the contrast and the discernment of different tissues. With high contrast and optimal signal to noise ratio, the image resolution is depend on FOV and number of data points of a picture, but T2* effects have an additional influence.
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• View the DATABASE results for 'Image Resolution' (9).Open this link in a new window


• View the NEWS results for 'Image Resolution' (1).Open this link in a new window.
 
Further Reading:
  Basics:
The Basics of MRI
   by www.cis.rit.edu    
  News & More:
Optimizing Musculoskeletal MR
   by rad.usuhs.mil    
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
Infinion 1.5TPanorama 0.2InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
From Philips Medical Systems; www.medical.philips.com/main/products/mri/products/infinion1.5t/features/ Philips Infinion 1.5 T is designed to maximize the efficiency and quality of patient care. Developed with the patient in mind, the Infinion is the shortest and most open 1.5T scanner available. The unique 'ultra short' 1.4 m magnet assures patient comfort and acceptance without compromising image quality and clinical performance.
Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
Ultra short bore
Head, head / neck, integrated C-spine, L/T spine array, small large GP coils, body flex array, torso pelvis array, breast array, endocavitary, shoulder array, lower extremity, hand / wrist, cardiac, PV array
SYNCHRONIZATION
ECG/peripheral, respiratory gating
PULSE SEQUENCES
SE, TSE, SS TSE, EPI, IR, STIR, FLAIR, FFE, TFE, T1 TFE, T2 TFE, Presat, Fatsat, MTC, Diff-opt., Angiography: PCA, MCA, TOF
IMAGING MODES
Single slice, single volume, multi slice, multi volume
TR
3.1 msec minimum
TE
0.9 msec minimum
SINGLE/MULTI SLICE
80 images/sec std.; up to320 opt.@256
FOV
0.4 - 56 cm
2D: 0.3 mm; 3D: 0.2 mm
1024 x 1024
MEASURING MATRIX
8 x 8 to 1024 x 1024
PIXEL INTENSITY
256 gray scale
BORE DIAMETER
or W x H
60 cm diameter (patient)
MAGNET WEIGHT
4100 kg w/cryogen's
H*W*D
233 (lead fitted) x 198 x 140 cm
POWER REQUIREMENTS
400/480 V
COOLING SYSTEM TYPE
Closed loop, chilled water
CRYOGEN USE
0.06 L/hr helium
STRENGTH
30 mT/m
5-GAUSS FRINGE FIELD
3.0 m / 5.0 m
Passive/active
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• View the DATABASE results for 'Infinion 1.5T™' (2).Open this link in a new window

MRI Resources 
Abdominal Imaging - Equipment - IR - MRI Technician and Technologist Career - Collections - Contrast Agents
 
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