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 'Automatic Bolus Detection' 
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Result : Searchterm 'Automatic Bolus Detection' found in 1 term [] and 4 definitions []
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MRI Resources 
MRI Technician and Technologist Jobs - Universities - Shoulder MRI - Case Studies - MRA - Abdominal Imaging
 
Automatic Bolus DetectionInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
Automatic bolus detection is used to trigger the begin of the MRI scan with the time the contrast agent reaches the region of interest. The acquisition process is started once the signal is increased in this region. There are similar methods used by the scanner manufacturer (see MRI Acronyms for Automatic Bolus Detection). After injection of the contrast agent the region of interest is monitored (e.g. with a spin echo or gradient echo sequence). When the signal increases the scan is automatically triggered or the operator is informed.

See also Abdominal Imaging, Bolus Injection, Fluoroscopic Triggering, Care Bolus, and Bolus Tracking.
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Further Reading:
  Basics:
Fast Contrast Enhanced Imaging with Projection Reconstruction(.pdf)
   by ece.ut.ac.ir    
  News & More:
Abdominal MR angio: fast, reproducible, and safe
   by www.diagnosticimaging.com    
MRI Resources 
Stimulator pool - Sequences - Shoulder MRI - Examinations - Mobile MRI - Services and Supplies
 
Contrast Enhanced Magnetic Resonance AngiographyInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - MRA -
 
(CE MRA) Contrast enhanced MR angiography is based on the T1 values of blood, the surrounding tissue, and paramagnetic contrast agent.
T1-shortening contrast agents reduces the T1 value of the blood (approximately to 50 msec, shorter than that of the surrounding tissues) and allow the visualization of blood vessels, as the images are no longer dependent primarily on the inflow effect of the blood. Contrast enhanced MRA is performed with a short TR to have low signal (due to the longer T1) from the stationary tissue, short scan time to facilitate breath hold imaging, short TE to minimize T2* effects and a bolus injection of a sufficient dose of a gadolinium chelate.
Images of the region of interest are performed with 3D spoiled gradient echo pulse sequences. The enhancement is maximized by timing the contrast agent injection such that the period of maximum arterial concentration corresponds to the k-space acquisition. Different techniques are used to ensure optimal contrast of the arteries e.g., bolus timing, automatic bolus detection, bolus tracking, care bolus. A high resolution with near isotropic voxels and minimal pulsatility and misregistration artifacts should be striven for. The postprocessing with the maximum intensity projection (MIP) enables different views of the 3D data set.
Unlike conventional MRA techniques based on velocity dependent inflow or phase shift techniques, contrast enhanced MRA exploits the gadolinium induced T1-shortening effects. CE MRA reduces or eliminates most of the artifacts of time of flight angiography or phase contrast angiography. Advantages are the possibility of in plane imaging of the blood vessels, which allows to examine large parts in a short time and high resolution scans in one breath hold. CE MRA has found a wide acceptance in the clinical routine, caused by the advantages:
3D MRA can be acquired in any plane, which means that greater vessel coverage can be obtained at high resolution with fewer slices (aorta, peripheral vessels);
the possibility to perform a time resolved examination (similarly to conventional angiography);
no use of ionizing radiation; paramagnetic agents have a beneficial safety.
 
Images, Movies, Sliders:
 CE-MRA of the Carotid Arteries  Open this link in a new window
    
SlidersSliders Overview

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

 CE-MRA of the Carotid Arteries Colored MIP  Open this link in a new window
    
SlidersSliders Overview

 
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• View the DATABASE results for 'Contrast Enhanced Magnetic Resonance Angiography' (14).Open this link in a new window


• View the NEWS results for 'Contrast Enhanced Magnetic Resonance Angiography' (2).Open this link in a new window.
 
Further Reading:
  Basics:
Contrast-Enhanced MR Angiography(.pdf)
   by ric.uthscsa.edu    
CONTRAST ENHANCED MR ANGIOGRAPHY – PRINCIPLES, APPLICATIONS, TIPS AND PITFALLS(.pdf)
  News & More:
CONTRAST-ENHANCED MRA OF THE CAROTIDS(.pdf)
PERIPHERAL VASCULAR MAGNETIC RESONANCE ANGIOGRAPHY(.pdf)
CONTRAST ENHANCED MRI OF THE LIVER STATE-OF-THE-ART(.pdf)
MRI Resources 
Image Quality - NMR - Online Books - Portals - Devices - Contrast Enhanced MRI
 
Fluoroscopic TriggeringForum -
related threads
 
Fluoroscopic triggering is a method (see automatic bolus detection) used to time the start of a contrast enhanced dynamic or MRA sequence. After the bolus injection of a contrast medium, the bolus can be tracked with a real time sequence. The operator starts the sequence, when the contrast is visual identified on the monitor.
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• View the DATABASE results for 'Fluoroscopic Triggering' (2).Open this link in a new window

 
Further Reading:
  Basics:
Fast Contrast Enhanced Imaging with Projection Reconstruction(.pdf)
   by ece.ut.ac.ir    
MRI Resources 
Manufacturers - MRA - Portals - Intraoperative MRI - Process Analysis - Databases
 
MAGNETOM Aera
 
www.healthcare.siemens.com/magnetic-resonance-imaging/0-35-to-1-5t-mri-scanner/magnetom-aera/ From Siemens Medical Systems;
Received FDA clearance in 2010.
The MAGNETOM Aera is a patient friendly, comfortable 1.5 Tesla MRI system with advanced radio frequency chain.
The system is equipped with the Tim 4G and Dot system (Total imaging matrix + Day optimizing throughput), to enhance both productivity and image quality.
Tim 4G technology provides improved SNR. The standard system configuration of 48 radio frequency channels and 204 coil elements creates an imaging matrix that allows maximum use of coil elements at full field of view. Dot provides improved image consistency through new features like auto align, auto FoV and automatic bolus detection.
Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
Open bore
Head, spine, torso/ body coil, neurovascular, cardiac, neck, shoulder, knee, wrist, foot//ankle and multi-purpose flex coils. Peripheral vascular, breast, shoulder. Up to 60% more SNR with Tim 4G.
CHANNELS (min. / max. configuration)
48, 64
IMAGING TECHNIQUES
iPAT, mSENSE and GRAPPA (image, k-space), noncontrast angiography, plaque imaging, radial motion compensation, Dixon, improved workflow with Dot, Caipirinha - single digit breath-holds for 3-D body imaging.
MINIMUM TR
3-D GRE: 0.95 (256 matrix)
MINIMUM TE
3-D GRE: 0.22 (256 matrix), Ultra-short TE
FOV
0.5 - 50
BORE DIAMETER
or W x H
At isocenter: L-R 70 cm, A-P (with table) 55 cm
TABLE CAPACITY
250 kg
MAGNET WEIGHT (gantry included)
3121 kg
DIMENSION H*W*D (gantry included)
145 x 231 x 219 cm
5-GAUSS FRINGE FIELD
2.5 m / 4.0 m
CRYOGEN USE
Zero boil off rate, approx. 10 years
COOLING SYSTEM
Water
up to 200 T/m/s
MAX. AMPLITUDE
33 or 45 mT/m
3 linear with 20 coils, 5 nonlinear 2nd-order
POWER REQUIREMENTS
380 / 400 / 420 / 440 / 460 / 480 V, 3-phase + ground; 85 kVA
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MRI Resources 
Online Books - MRA - Functional MRI - Liver Imaging - Examinations - MRI Centers
 
Time Resolved Imaging of Contrast KineticsInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
(TRICKS) Time resolved imaging of contrast kinetics is a MRI technique, which increases the temporal resolution of dynamic contrast enhanced magnetic resonance angiography (CE-MRA) sequences. The K-space is divided into regions by increasing the sampling rate at the lower spatial frequencies and by reducing the sampling rate at the higher spatial frequencies. Since the time duration between two frames is shortened, it can be observed how frequently and how quickly the images are repeated at the exact same location.
TRICKS is particularly useful for dynamic vascular studies with high temporal resolution. TRICKS improves the calculation of the contrast bolus arrival and improves the characterization of arterio-venous malformations (AVMs).

See also Automatic Bolus Detection, MRA, Cardiac MRI.
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• View the DATABASE results for 'Time Resolved Imaging of Contrast Kinetics' (2).Open this link in a new window

 
Further Reading:
  Basics:
Optimal k-Space Sampling for Dynamic Contrast-Enhanced MRI with an Application to MR Renography
Thursday, 5 November 2009   by www.ncbi.nlm.nih.gov    
MRI Resources 
Abdominal Imaging - MRI Reimbursement - Developers - Online Books - Knee MRI - Non-English
 
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