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MRI Resources 
Lung Imaging - Process Analysis - Pacemaker - Functional MRI - Pediatric and Fetal MRI -
 
Short Repetition TechniquesInfoSheet: - Sequences -
Intro, Overview, 
Types of, 
etc.
 
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• View the DATABASE results for 'Short Repetition Techniques' (2).Open this link in a new window

Short T1 Inversion RecoveryInfoSheet: - Sequences -
Intro, Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(STIR) Also called Short Tau (t) (inversion time) Inversion Recovery. STIR is a fat suppression technique with an inversion time t = T1 ln2 where the signal of fat is zero (T1 is the spin lattice relaxation time of the component that should be suppressed). To distinguish two tissue components with this technique, the T1 values must be different. Fluid Attenuation Inversion Recovery (FLAIR) is a similar technique to suppress water.
Inversion recovery doubles the distance spins will recover, allowing more time for T1 differences. A 180° preparation pulse inverts the net magnetization to the negative longitudinal magnetization prior to the 90° excitation pulse. This specialized application of the inversion recovery sequence set the inversion time (t) of the sequence at 0.69 times the T1 of fat. The T1 of fat at 1.5 Tesla is approximately 250 with a null point of 170 ms while at 0.5 Tesla its 215 with a 148 ms null point. At the moment of excitation, about 120 to 170 ms after the 180° inversion pulse (depending of the magnetic field) the magnetization of the fat signal has just risen to zero from its original, negative, value and no fat signal is available to be flipped into the transverse plane.
When deciding on the optimal T1 time, factors to be considered include not only the main field strength, but also the tissue to be suppressed and the anatomy. In comparison to a conventional spin echo where tissues with a short T1 are bright due to faster recovery, fat signal is reversed or darkened. Because body fluids have both a long T1 and a long T2, it is evident that STIR offers the possibility of extremely sensitive detection of body fluid. This is of course, only true for stationary fluid such as edema, as the MRI signal of flowing fluids is governed by other factors.

See also Fat Suppression and Inversion Recovery Sequence.
 
Images, Movies, Sliders:
 Sagittal Knee MRI Images STIR  Open this link in a new window
      

 
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• View the DATABASE results for 'Short T1 Inversion Recovery' (3).Open this link in a new window

 
Further Reading:
  Basics:
Can Short Tau Inversion Recovery (STIR) Imaging Be Used as a Stand-Alone Sequence To Assess a Perianal Fistulous Tract on MRI? A Retrospective Cohort Study Comparing STIR and T1-Post Contrast Imaging
Wednesday, 17 January 2024   by www.cureus.com    
  News & More:
Generating Virtual Short Tau Inversion Recovery (STIR) Images from T1- and T2-Weighted Images Using a Conditional Generative Adversarial Network in Spine Imaging
Wednesday, 25 August 2021
Short tau inversion recovery (STIR) after intravenous contrast agent administration obscures bone marrow edema-like signal on forefoot MRI
Tuesday, 13 July 2021   by www.springermedizin.de    
MRI Resources 
Service and Support - Software - Mobile MRI - RIS - MRCP - Chemistry
 
Short T1-Relaxation Gastrointestinal AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.
 
Protons in -CH2- groups, e.g., contained in fatty emulsions, mineral or vegetable oil or sucrose polyester, have a fast relaxation and short T1 time. These agents with short T1-relaxation, if used in gastrointestinal imaging, produce bright signal intensities in the intestine on T1 weighted sequences. Palatable oil emulsions can produce appropriate contrast opacification of the stomach as well as the small bowel, but caused by absorption in the distal small bowel these materials are not suitable for use in MRI colonoscopy.

See also Positive Oral Contrast Agents and Gastrointestinal Paramagnetic Contrast Agents.
 
Images, Movies, Sliders:
 MR Colonography Gadolinium per Rectum  Open this link in a new window
      

Courtesy of  Robert R. Edelman
 
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• View the DATABASE results for 'Short T1-Relaxation Gastrointestinal Agents' (2).Open this link in a new window

Shot
 
Shots are split phase encoding steps (sub-acquisitions).
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• View the NEWS results for 'Shot' (3).Open this link in a new window.

• View the DATABASE results for 'Shot' (46).Open this link in a new window

 
Further Reading:
  News & More:
Utility of the FIESTA Pulse Sequence in Body Oncologic Imaging: Review
June 2009   by www.ajronline.org    
Shoulder MRI
 
MRI of the shoulder with its excellent soft tissue discrimination, and high spatial resolution offers the best noninvasive way to study the shoulder. MRI images of the bone, muscles and tendons of the glenohumeral joint can be obtained in any oblique planes and projections. MRI gives excellent depiction of rotator cuff tears, injuries to the biceps tendon and damage to the glenoid labrum. Shoulder MRI is better than ultrasound imaging at depicting structural changes such as osteophytic spurs, ligament thickening, and acromial shape that may have predisposed to tendon degeneration.
A dedicated shoulder coil and careful patient positioning in external rotation with the shoulder as close as reasonably possible to the center of the magnet is necessary for a good image quality. If possible, the opposite shoulder should be lifted up, so that the patient lies on the imaged shoulder in order to rotate and fix this shoulder to reduce motion during breathing.
Axial, coronal oblique, and sagittal oblique proton density with fat suppression, T2 and T1 provide an assessment of the rotator cuff, biceps, deltoid, acromio-clavicular joint, the glenohumeral joint and surrounding large structures. If a labral injury is suspected, a Fat Sat gradient echo sequence is recommended. In some cases, a direct MR shoulder arthrogram with intra-articular injection of dilute gadolinium or an indirect arthrogram with imaging 20 min. after intravenous injection may be helpful.

See also Imaging of the Extremities.
 
Images, Movies, Sliders:
 Anatomic Imaging of the Shoulder  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 
Radiology-tip.comradArthrography
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Medical-Ultrasound-Imaging.comLow Intensity Pulsed Ultrasound,  Musculoskeletal and Joint Ultrasound
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• View the NEWS results for 'Shoulder MRI' (1).Open this link in a new window.

• View the DATABASE results for 'Shoulder MRI' (3).Open this link in a new window

 
Further Reading:
  News & More:
The Spectrum of Shoulder Pathologies on Magnetic Resonance Imaging: A Pictorial Review
Wednesday, 6 September 2023   by www.cureus.com    
MRI costs wide-ranging
Thursday, 14 April 2011   by www.chieftain.com    
MRE Could Provide A Definitive Diagnosis For People With Muscle Pain, Study Shows
Friday, 30 November 2007   by www.sciencedaily.com    
Peer-Reviewed Study Concludes The FONAR UPRIGHT™ MRI Could Serve as the “Standard Procedure of Care” for Pediatric Shoulder Malady
Wednesday, 30 May 2007   by www.fonar.com    
MRI Resources 
Calculation - - Societies - Jobs - Brain MRI - DICOM
 
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MRI is trending to low field magnets :
reduced costs will lead to this change 
AI will close the gap to high field 
only in remote areas 
is only temporary 
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