General
MRI of the abdomen can consist of
T1 or
T2 weighted spin echo,
fast spin echo (
FSE,
TSE) or
gradient echo sequences with
fat suppression and
contrast enhanced MRI techniques. The examined organs include
liver,
pancreas, spleen, kidneys, adrenals as well as parts of the stomach and intestine (see also
gastrointestinal imaging).
Respiratory compensation and
breath hold imaging is mandatory for a good
image quality.
T1 weighted sequences are more sensitive for lesion detection than
T2 weighted sequences at 0.5 T, while higher field strengths (greater than 1.0 T),
T2 weighted and spoiled
gradient echo sequences are used for focal lesion detection.
Gradient
echo in phase T1 breath hold can be performed as a dynamic series with the ability to visualize the blood distribution. Phases of
contrast enhancement include the capillary or arterial dominant
phase for demonstrating hypervascular lesions, in
liver imaging the portal venous
phase demonstrates the maximum difference between the
liver and hypovascular lesions, while the
equilibrium phase demonstrates interstitial disbursement for edematous and malignant tissues.
Out of phase gradient echo imaging for the abdomen is a lipid-type tissue sensitive sequence and is useful for the visualization of focal hepatic lesions, fatty
liver (see also
Dixon), hemochromatosis, adrenal lesions and renal masses.
The standards for abdominal
MRI vary according to clinical sites based on sequence availability and
MRI equipment.
Specific abdominal imaging coils and liver-specific
contrast agents targeted to the healthy
liver tissue improve the detection and localization of lesions.
See also
Hepatobiliary Contrast Agents,
Reticuloendothelial Contrast Agents, and
Oral Contrast Agents.
For Ultrasound Imaging (USI) see
Abdominal Ultrasound at
Medical-Ultrasound-Imaging.com.
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