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Result : Searchterm 'Breath Hold Imaging' found in 1 term [] and 6 definitions [], (+ 14 Boolean[] results
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Fast Imaging with Steady PrecessionInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
(TrueFISP) True fast imaging with steady state precession is a coherent technique that uses a fully balanced gradient waveform. The image contrast with TrueFISP is determined by T2*//T1 properties and mostly depending on TR. The speed and relative motion insensitivity of acquisition help to make the technique reliable, even in patients who have difficulty with holding their breath.
Recent advances in gradient hardware have led to a decreased minimum TR. This combined with improved field shimming capabilities and signal to noise ratio, has allowed TrueFISP imaging to become practical for whole-body applications. There's mostly T2* weighting. With the used ultrashort TR-times T1 weighting is almost impossible. One such application is cardiac cine MR with high myocardium-blood contrast. Spatial and temporal resolution can be substantially improved with this technique, but contrast on the basis of the ratio of T2* to T1 is not sufficiently high in soft tissues. By providing T1 contrast, TrueFISP could then document the enhancement effects of T1 shortening contrast agents. These properties are useful for the anatomical delineation of brain tumors and normal structures. With an increase in SNR ratio with minimum TR, TrueFISP could also depict the enhancement effect in myoma uteri. True FSIP is a technique that is well suited for cardiac MR imaging. The imaging time is shorter and the contrast between the blood and myocardium is higher than that of FLASH.

See Steady State Free Precession.
 
Images, Movies, Sliders:
 Cardiac Infarct 4 Chamber Cine 1  Open this link in a new window
    
 
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Further Reading:
  Basics:
Accurate T1 Quantification Using a Breath-hold Inversion Recovery TrueFISP Sequence
2003   by rsna2003.rsna.org    
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Volumetric Interpolated Breath Hold ExaminationInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
(VIBE) A T1 weighted 3D FLASH breath hold technique with fat selective prepulse.
Used for dynamic liver, pancreas, pelvis, thorax, orbita imaging and MR colonoscopy.
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Further Reading:
  Basics:
The Effects of Breathing Motion on DCE-MRI Images: Phantom Studies Simulating Respiratory Motion to Compare CAIPIRINHA-VIBE, Radial-VIBE, and Conventional VIBE
Tuesday, 7 February 2017   by www.kjronline.org    
MRI techniques improve pulmonary embolism detection
Monday, 19 March 2012   by medicalxpress.com    
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Incoherent Gradient Echo (RF Spoiled)InfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
A gradient echo is generated by using a pair of bipolar gradient pulses. The gradient field is negatively pulsed, causing the spins of the xy-magnetization to dephase. A second gradient pulse is applied with the opposite polarity. During the pulsing, the spins that dephased begin to rephase and generate a gradient echo.
Spoiling can be accomplished by RF or a gradient. The incoherent RF spoiled type of a gradient echo sequence use a continuous shifting of the RF pulse to spoil the residual transverse magnetization. The phase of the RF excitation and receiver channel are varied pseudo randomly with each excitation cycle to prevent the xy magnetization from achieving steady state. T2* does not dominate image contrast, so T1 and PD weighting is practical. This method is effective and can be used to achieve a shorter TR, due to a lack of additional gradients. Spoiling eliminates the effect of the remaining xy-magnetization and leads to steady state longitudinal magnetization. These sequences can be used for breath hold, dynamic imaging and in cine and volume acquisitions.
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Segmented K-Space Data Acquisition
 
A set of k-space lines collected in a specified order but not constituting a complete coverage of k-space, thus can be used in conjunction with all ultrafast MRI techniques. Several segmental acquisitions may need to be run for complete coverage of k-space. If these lines are recorded for a single rather than multiple images, imaging time can be shortened considerably maintaining an acceptable temporal resolution.
For example, rapidly acquiring eight k-space lines per segment after each trigger until 128 lines of k-space are acquired in 16 triggers, thus makes image acquisition of multiple cardiac phases or anatomical slices possible in a breath-hold.
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Cardiovascular ImagingMRI Resource Directory:
 - Cardiovascular Imaging -
 
Cardiovascular MR imaging includes the complete anatomical display of the heart with CINE imaging of all phases of the heartbeat. Ultrafast techniques make breath hold three-dimensional coverage of the heart in different cardiac axes feasible. Cardiac MRI provides reliable anatomical and functional assessment of the heart and evaluation of myocardial viability and coronary artery disease by a noninvasive diagnostic imaging technique.
Cardiovascular MRI offers potential advantages over radioisotopic techniques because it provides superior spatial resolution, does not use ionizing radiation, has no imaging orientations constraints and contrast resolution better than echocardiography. It also offers direct visualization and characterization of atherosclerotic plaques and diseased vessel walls and surrounding tissues in cardiovascular research.
MRI perfusion approaches measure the alteration of regional myocardial magnetic properties after the intravenous injection of contrast agents and assess the extent of injury after a myocardial infarction and the presence of myocardial viability with a technique based on late enhancement. Extracellular MRI contrast agents, like Gd-DTPA, accumulate only in irreversibly damaged myocardium after a time period of at least 10 minutes.
This type of patients may also have an implanted cardiac stent, bypass or a cardiac pacemaker and special caution should be observed on the MRI safety and the contraindications. While a number of coronary stents have been tested and reported to be MRI compatible, coronary stents must be assessed on an individual basis, with the medical team weighing the risks and benefits of the MRI procedure.

Cardiac MRI overview:
•
Myocardial perfusion imaging and viability
•
Calculation of ventricular volume, myocardial mass and wall thickness
•
Functional parameters
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Description of a stenosis or aneurysma
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Anatomical display of the heart, vessels and the surrounding tissue

Cardiovascular MRI has become one of the most effective noninvasive imaging techniques for almost all groups of heart and vascular disease.
 
Images, Movies, Sliders:
 Angulation of Cardiac Planes Cine Images of Septal Infarct  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Left Circumflex Ischemia First-pass Contrast Enhancement  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Delayed Myocardial Contrast Enhancement from Infarct  Open this link in a new window
 
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• View the DATABASE results for 'Cardiovascular Imaging' (18).Open this link in a new window


• View the NEWS results for 'Cardiovascular Imaging' (6).Open this link in a new window.
 
Further Reading:
  Basics:
Cardiac MRI - Technical Aspects Primer
Wednesday, 7 August 2002
Coronary Artery Disease: Combined Stress MR Imaging Protocol-One-Stop Evaluation of Myocardial Perfusion and Function1
   by radiology.rsnajnls.org    
A Guide To Cardiac Imaging
   by www.simplyphysics.com    
  News & More:
New Imaging Technique Reveals Different Heart Motions by Age, Gender
Thursday, 10 December 2009   by www.sciencedaily.com    
MRI Resources 
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