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Searchterm 'Contrast Agents' was also found in the following services: 
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News  (49)  Resources  (7)  Forum  (8)  
 
Gastrointestinal Paramagnetic Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Paramagnetic substances, for example Gd-DTPA solutions, are used as MRI oral contrast agents in gastrointestinal imaging to depict the lumen of the digestive organs. Different Gd-DTPA solutions or zeolites containing gadolinium can be used e.g., for diagnosis of delayed gastric emptying, diagnosis of Crohn's disease etc.
Low concentrations of gastrointestinal paramagnetic contrast agents cause a reduction in T1 relaxation time; consequently, these agents act on T1 weighted images by increasing the signal intensity of the bowel lumen. High concentrations cause T2 shortening by decreasing the signal, similar to superparamagnetic iron oxide. Gd-DTPA chelates are unstable at the low pH in the stomach, therefore buffering is necessary for oral use.

See also Gadopentetate Gastrointestinal, Gadolinium Zeolite, Negative Oral Contrast Agents, Gastrointestinal Superparamagnetic Contrast Agents, and Ferric ammonium citrate.
 
Images, Movies, Sliders:
 MR Colonography Gadolinium per Rectum  Open this link in a new window
      

Courtesy of  Robert R. Edelman
 
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Searchterm 'Contrast Agents' was also found in the following services: 
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Radiology  (46) Open this link in a new windowUltrasound  (75) Open this link in a new window
Gastrointestinal Superparamagnetic Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Gastrointestinal (GI) superparamagnetic contrast agents are used in MRI to improve the visualization of e.g., the intestinal tract, the pancreas (see MRCP), etc. Disadvantages are susceptibility artifacts e.g., dependent on delayed imaging or large volumes resulting in artifacts in the colon and distal small bowel loops related to higher concentration of the particles and absorption of the fluid.
Different types of MRI gastrointestinal superparamagnetic contrast agents:
•
Magnetite albumin microsphere

Usually gastrointestinal superparamagnetic contrast media consist of small iron oxide crystals (ferrites), which produce a signal reduction in the stomach and bowel after oral administration. The T2 shortening caused by these particles is produced from the local magnetic field inhomogeneities associated with the large magnetic moments of superparamagnetic particles. Ferrites are iron oxides of the general formula Fe203.MO, where M is a divalent metal ion and may be mixed with Fe3O4 in different preparations. Ferrites can produce symptoms of nausea after oral administration, as well as flatulence and a transient rise in serum iron. Embedding in inert substances reduce side effects by decreasing the absorption and interaction with body tissues. Combining these contrast materials with polymers such as polyethylene glycol or cellulose, or with sugars such as dextrose, results in improved T1 and/or T2 relaxivity compared with that of the contrast agent alone.

See also Negative Oral Contrast Agents, Gastrointestinal Diamagnetic Contrast Agents, Relaxivity, and Combination Oral Contrast Agents.
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• View the DATABASE results for 'Gastrointestinal Superparamagnetic Contrast Agents' (6).Open this link in a new window

 
Further Reading:
  Basics:
Negative GI Contrast Agents
   by www.mritutor.org    
MRI Resources 
Intraoperative MRI - Resources - Open Directory Project - MR Myelography - IR - Pathology
 
Contrast MediumForum -
related threadsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
A contrast medium (or contrast agent) is a chemical substance introduced to the anatomical or functional region being imaged, to increase the differences between different tissues or between normal and abnormal tissue, by altering the relaxation times.
The chemical composition of the contrast media determines the specific usage. Similar to nuclear imaging is the intention in development of MR contrast media a high affinity to different organs or even tumors (e.g. necrosis avid contrast agent).
In 'contrast' to nuclear imaging contrast agents MR contrast media do not contain radiopharmaceuticals and the concentrations are about 100 times higher. Nuclear imaging contrast agents are direct contrast agents;; they are directly visible caused by their radioactivity. MR contrast agents affect the targeted tissue; they are indirect contrast agents.
See also Contrast Agents, the info sheet gives an overview and more in-depth information about different types of MRI contrast medium.
 
Images, Movies, Sliders:
 Breast MRI Images T1 Pre - Post Contrast  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

 
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• View the DATABASE results for 'Contrast Medium' (26).Open this link in a new window


• View the NEWS results for 'Contrast Medium' (2).Open this link in a new window.
 
Further Reading:
  Basics:
Analysis of MRI contrast agents
Thursday, 17 November 2022   by www.sciencedaily.com    
Contrast Agents: Safety Profile
   by www.clinical-mri.com    
Questions and Answers on Gadolinium-Based Contrast Agents
Friday, 9 January 2009   by www.fda.gov    
  News & More:
CT contrast reaction raises MRI contrast risk
Tuesday, 22 February 2022   by www.sciencedaily.com    
Polysaccharide-Core Contrast Agent as Gadolinium Alternative for Vascular MR
Monday, 8 March 2021   by www.diagnosticimaging.com    
GE Healthcare expands MRI contrast media product range in Europe with launch of macrocyclic agent ClariscanTM
Wednesday, 1 March 2017   by www.businesswire.com    
Lawson scientists develop commercial imaging product for PET/MRI scanners
Wednesday, 9 December 2015   by www.news-medical.net    
New oxygen-enhanced MRI scan 'helps identify most dangerous tumours'
Thursday, 10 December 2015   by www.dailymail.co.uk    
Contrast MRIs cause claims, concern, over residual metal in brain
Tuesday, 8 December 2015   by www.afr.com    
A Manganese Alternative to Gadolinium for MRI Contrast.
Friday, 4 December 2015   by www.ncbi.nlm.nih.gov    
Searchterm 'Contrast Agents' was also found in the following services: 
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News  (49)  Resources  (7)  Forum  (8)  
 
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    
Searchterm 'Contrast Agents' was also found in the following services: 
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Radiology  (46) Open this link in a new windowUltrasound  (75) Open this link in a new window
Liver ImagingForum -
related threadsMRI Resource Directory:
 - Liver Imaging -
 
Liver imaging can be performed with sonography, computed tomography (CT) and magnetic resonance imaging (MRI). Ultrasound is, caused by the easy access, still the first-line imaging method of choice; CT and MRI are applied whenever ultrasound imaging yields vague results. Indications are the characterization of metastases and primary liver tumors e.g., benign lesions such as focal nodular hyperplasia (FNH), adenoma, hemangioma and malignant lesions (cancer) such as hepatocellular carcinomas (HCC). The decision, which medical imaging modality is more suitable, MRI or CT, is dependent on the different factors. CT is less costly and more widely available; modern multislice scanners provide high spatial resolution and short scan times but has the disadvantage of radiation exposure.
With the introduction of high performance MR systems and advanced sequences the image quality of MRI for the liver has gained substantially. Fast spin echo or single shot techniques, often combined with fat suppression, are the most common T2 weighted sequences used in liver MRI procedures. Spoiled gradient echo sequences are used as ideal T1 weighted sequences for evaluating of the liver. The repetition time (TR) can be sufficiently long to acquire enough sections covering the entire liver in one pass, and to provide good signal to noise. The TE should be the shortest in phase echo time (TE), which provides strong T1 weighting, minimizes magnetic susceptibility effects, and permits acquisition within one breath hold to cover the whole liver. A flip angle of 80° provides good T1 weighting and less of power deposition and tissue saturation than a larger flip angle that would provide comparable T1 weighting.
Liver MRI is very dependent on the administration of contrast agents, especially when detection and characterization of focal lesions are the issues. Liver MRI combined with MRCP is useful to evaluate patients with hepatic and biliary disease.
Gadolinium chelates are typical non-specific extracellular agents diffusing rapidly to the extravascular space of tissues being cleared by glomerular filtration at the kidney. These characteristics are somewhat problematic when a large organ with a huge interstitial space like the liver is imaged. These agents provide a small temporal imaging window (seconds), after which they begin to diffuse to the interstitial space not only of healthy liver cells but also of lesions, reducing the contrast gradient necessary for easy lesion detection. Dynamic MRI with multiple phases after i.v. contrast media (Gd chelates), with arterial, portal and late phase images (similar to CT) provides additional information.
An additional advantage of MRI is the availability of liver-specific contrast agents (see also Hepatobiliary Contrast Agents). Gd-EOB-DTPA (gadoxetate disodium, Gadolinium ethoxybenzyl dimeglumine, EOVIST Injection, brand name in other countries is Primovist) is a gadolinium-based MRI contrast agent approved by the FDA for the detection and characterization of known or suspected focal liver lesions.
Gd-EOB-DTPA provides dynamic phases after intravenous injection, similarly to non-specific gadolinium chelates, and distributes into the hepatocytes and bile ducts during the hepatobiliary phase. It has up to 50% hepatobiliary excretion in the normal liver.
Since ferumoxides are not eliminated by the kidney, they possess long plasmatic half-lives, allowing circulation for several minutes in the vascular space. The uptake process is dependent on the total size of the particle being quicker for larger particles with a size of the range of 150 nm (called superparamagnetic iron oxide). The smaller ones, possessing a total particle size in the order of 30 nm, are called ultrasmall superparamagnetic iron oxide particles and they suffer a slower uptake by RES cells. Intracellular contrast agents used in liver MRI are primarily targeted to the normal liver parenchyma and not to pathological cells. Currently, iron oxide based MRI contrast agents are not marketed.
Beyond contrast enhanced MRI, the detection of fatty liver disease and iron overload has clinical significance due to the potential for evolution into cirrhosis and hepatocellular carcinoma. Imaging-based liver fat quantification (see also Dixon) provides noninvasively information about fat metabolism; chemical shift imaging or T2*-weighted imaging allow the quantification of hepatic iron concentration.

See also Abdominal Imaging, Primovistâ„¢, Liver Acquisition with Volume Acquisition (LAVA), T1W High Resolution Isotropic Volume Examination (THRIVE) and Bolus Injection.

For Ultrasound Imaging (USI) see Liver Sonography at Medical-Ultrasound-Imaging.com.
 
Images, Movies, Sliders:
 Anatomic Imaging of the Liver  Open this link in a new window
      

 MRI Liver T2 TSE  Open this link in a new window
    
 
Radiology-tip.comradAbdomen CT,  Biliary Contrast Agents
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Medical-Ultrasound-Imaging.comLiver Sonography,  Vascular Ultrasound Contrast Agents
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• View the DATABASE results for 'Liver Imaging' (13).Open this link in a new window


• View the NEWS results for 'Liver Imaging' (10).Open this link in a new window.
 
Further Reading:
  Basics:
Comparison of liver scintigraphy and the liver-spleen contrast in Gd-EOB-DTPA-enhanced MRI on liver function tests
Thursday, 18 November 2021   by www.nature.com    
Liver Imaging Today
Friday, 1 February 2013   by www.healthcare.siemens.it    
Elastography: A Useful Method in Depicting Liver Hardness
Thursday, 15 April 2010   by www.sciencedaily.com    
Iron overload: accuracy of in-phase and out-of-phase MRI as a quick method to evaluate liver iron load in haematological malignancies and chronic liver disease
Friday, 1 June 2012   by www.ncbi.nlm.nih.gov    
  News & More:
Utility and impact of magnetic resonance elastography in the clinical course and management of chronic liver disease
Saturday, 20 January 2024   by www.nature.com    
Even early forms of liver disease affect heart health, Cedars-Sinai study finds
Thursday, 8 December 2022   by www.eurekalert.org    
For monitoring purposes, AI-aided MRI does what liver biopsy does with less risk, lower cost
Wednesday, 28 September 2022   by radiologybusiness.com    
Perspectum: High Liver Fat (Hepatic Steatosis) Linked to Increased Risk of Hospitalization in COVID-19 Patients With Obesity
Monday, 29 March 2021   by www.businesswire.com    
EMA's final opinion confirms restrictions on use of linear gadolinium agents in body scans
Friday, 21 July 2017   by www.ema.europa.eu    
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    
EORTC study aims to qualify ADC as predictive imaging biomarker in preoperative regimens
Monday, 4 January 2016   by www.eurekalert.org    
MRI effectively measures hemochromatosis iron burden
Saturday, 3 October 2015   by medicalxpress.com    
Total body iron balance: Liver MRI better than biopsy
Sunday, 15 March 2015   by www.eurekalert.org    
MRI Resources 
Stimulator pool - Jobs pool - MRI Technician and Technologist Jobs - MRI Centers - Liver Imaging - Patient Information
 
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