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 de
lineation 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 de
lineation.
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.
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