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Contrast Enhanced MR VenographyInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - MRA -
 
(CEMRV) A 3D dynamic contrast enhanced magnetic resonance venogram with acquisition timing to account for the later arrival of the contrast agent in the venous system. The pulse sequence used, is an enhanced 3D fast gradient echo sequence, the same sequence that is used for MR angiography.

For Ultrasound Imaging (USI) see Venous Ultrasound at Medical-Ultrasound-Imaging.com.
 
Images, Movies, Sliders:
 CE-MRA of the Carotid Arteries Colored MIP  Open this link in a new window
    
SlidersSliders Overview

 PCA-MRA 3D Brain Venography Colored MIP  Open this link in a new window
    

 
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Contrast Enhanced MRIInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Enhanced MRI -
 
Contrast enhanced MRI is a commonly used procedure in magnetic resonance imaging. The need to more accurately characterize different types of lesions and to detect all malignant lesions is the main reason for the use of intravenous contrast agents.
Some methods are available to improve the contrast of different tissues. The focus of dynamic contrast enhanced MRI (DCE-MRI) is on contrast kinetics with demands for spatial resolution dependent on the application. DCE-MR imaging is used for diagnosis of cancer (see also liver imaging, abdominal imaging, breast MRI, dynamic scanning) as well as for diagnosis of cardiac infarction (see perfusion imaging, cardiac MRI). Quantitative DCE-MRI requires special data acquisition techniques and analysis software.
Contrast enhanced magnetic resonance angiography (CE-MRA) allows the visualization of vessels and the temporal resolution provides a separation of arteries and veins. These methods share the need for acquisition methods with high temporal and spatial resolution.
Double contrast administration (combined contrast enhanced (CCE) MRI) uses two contrast agents with complementary mechanisms e.g., superparamagnetic iron oxide to darken the background liver and gadolinium to brighten the vessels. A variety of different categories of contrast agents are currently available for clinical use.
Reasons for the use of contrast agents in MRI scans are:
Relaxation characteristics of normal and pathologic tissues are not always different enough to produce obvious differences in signal intensity.
Pathology that is sometimes occult on unenhanced images becomes obvious in the presence of contrast.
Enhancement significantly increases MRI sensitivity.
In addition to improving delineation between normal and abnormal tissues, the pattern of contrast enhancement can improve diagnostic specificity by facilitating characterization of the lesion(s) in question.
Contrast can yield physiologic and functional information in addition to lesion delineation.
Imaging of arteries and veins with contrast enhanced angiography (CE MRA).

Common Indications:
Brain MRI : Preoperative/pretreatment evaluation and postoperative evaluation of brain tumor therapy, CNS infections, noninfectious inflammatory disease and meningeal disease.
Spine MRI : Infection/inflammatory disease, primary tumors, drop metastases, initial evaluation of syrinx, postoperative evaluation of the lumbar spine: disk vs. scar.
Breast MRI : Detection of breast cancer in case of dense breasts, implants, malignant lymph nodes, or scarring after treatment for breast cancer, diagnosis of a suspicious breast lesion in order to avoid biopsy.

For Ultrasound Imaging (USI) see Contrast Enhanced Ultrasound at Medical-Ultrasound-Imaging.com. See also Blood Pool Agents, Myocardial Late Enhancement, Cardiovascular Imaging, Contrast Enhanced MR Venography, Contrast Resolution, Dynamic Scanning, Lung Imaging, Hepatobiliary Contrast Agents, Contrast Medium and MRI Guided Biopsy.
 
Images, Movies, Sliders:
 Delayed Myocardial Contrast Enhancement from 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

 Normal Lung Gd Perfusion MRI  Open this link in a new window
 MRI of the Brain Stem with Temoral Bone and Auditory System  Open this link in a new window
    
SlidersSliders Overview

 Breast MRI Images T1 Pre - Post Contrast  Open this link in a new window
 
Radiology-tip.comradContrast Enhanced Computed Tomography
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Medical-Ultrasound-Imaging.comContrast Enhanced Ultrasound,  Contrast Enhanced Doppler Imaging
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• View the DATABASE results for 'Contrast Enhanced MRI' (14).Open this link in a new window


• View the NEWS results for 'Contrast Enhanced MRI' (8).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    
  News & More:
FDA Approves Gadopiclenol for Contrast-Enhanced Magnetic Resonance Imaging
Tuesday, 27 September 2022   by www.pharmacytimes.com    
Effect of gadolinium-based contrast agent on breast diffusion-tensor imaging
Thursday, 6 August 2020   by www.eurekalert.org    
Artificial Intelligence Processes Provide Solutions to Gadolinium Retention Concerns
Thursday, 30 January 2020   by www.itnonline.com    
Accuracy of Unenhanced MRI in the Detection of New Brain Lesions in Multiple Sclerosis
Tuesday, 12 March 2019   by pubs.rsna.org    
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    
Novel Imaging Technique Improves Prostate Cancer Detection
Tuesday, 6 January 2015   by health.ucsd.edu    
New oxygen-enhanced MRI scan 'helps identify most dangerous tumours'
Thursday, 10 December 2015   by www.dailymail.co.uk    
All-organic MRI Contrast Agent Tested In Mice
Monday, 24 September 2012   by cen.acs.org    
A groundbreaking new graphene-based MRI contrast agent
Friday, 8 June 2012   by www.nanowerk.com    
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Phase Contrast SequenceMRI Resource Directory:
 - Sequences -
 
(PC) Phase contrast sequences are the basis of MRA techniques utilizing the change in the phase shifts of the flowing protons in the region of interest to create an image. Spins that are moving along the direction of a magnetic field gradient receive a phase shift proportional to their velocity.
In a phase contrast sequence two data sets with a different amount of flow sensitivity are acquired. This is usually accomplished by applying gradient pairs, which sequentially dephase and then rephase spins during the sequence. Both 2D and 3D acquisition techniques can be applied with phase contrast MRA.
The first data set is acquired with a flow compensated sequence, i. e. without flow sensitivity. The second data set is acquired with a flow sensitive sequence. The amount of flow sensitivity is controlled by the strength of the bipolar gradient pulse pair, which is incorporated into the sequence. Stationary tissue undergoes no effective phase change after the application of the two gradients. Caused by the different spatial localization of flowing blood to stationary tissue, it experiences a different size of the second bipolar gradient compared to the first. The result is a phase shift.
The raw data from the two data sets are subtracted. By comparing the phase of signals from each location in the two sequences the exact amount of motion induced phase change can be determined to have a map where pixel brightness is proportional to spatial velocity.
Phase contrast images represent the signal intensity of the velocity of spins at each point within the field of view. Regions that are stationary remain black while moving regions are represented as grey to white.
The phase shift is proportional to the spin's velocity, and this allows the quantitative assessment of flow velocities. The difference MRI signal has a maximum value for opposite directions. This velocity is typically referred to as venc, and depends on the pulse amplitude and distance between the gradient pulse pair. For velocities larger than venc the difference signal is decreased constantly until it gets zero. Therefore, in a phase contrast angiography it is important to correctly set the venc of the sequence to the maximum flow velocity which is expected during the measurement. High venc factors of the PC angiogram (more than 40 cm/sec) will selectively image the arteries (PCA - arteriography), whereas a venc factor of 20 cm/sec will perform the veins and sinuses (PCV or MRV - venography).

See also Flow Quantification, Contrast Enhanced MR Venography, Time of Flight Angiography, Time Resolved Imaging of Contrast Kinetics.
 
Images, Movies, Sliders:
 PCA-MRA 3D Brain Venography Colored MIP  Open this link in a new window
    

 
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• View the DATABASE results for 'Phase Contrast Sequence' (5).Open this link in a new window

 
Further Reading:
  Basics:
MR–ANGIOGRAPHY(.pdf)
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