(DE FGRE, Dual/FFE, DE FFE) Simultaneously acquired in and out of phase TE gradient echo images. To quantitatively measure the signal intensity differences between out of phase and in phase images the parameters should be the same except for the TE.
The chemical shift artifact appearing on the out-of-phase image allows for the detection of lipids in the liver or adrenal gland, such as diffuse fatty infiltration, focal fatty infiltration, focal fatty sparing, benign adrenocortical masses and intracellular lipids within a hepatocellar neoplasm, where spin echo and fat suppression techniques are not as sensitive. Specific pathologies that have been reported include liver lipoma, angiomyolipoma, myelolipoma, metastatic liposarcoma, teratocarcinoma, melanoma, haemorrhagic neoplasm and metastatic choriocarcinoma.

A brand name for ferumoxide (same as Feridex®)
Endoremâ„¢ is a black to reddish-brown aqueous colloid of superparamagnetic iron oxide associated with dextran for intravenous administration as a MRI contrast medium for the detection of liver lesions that are associated with an alteration in the RES.
Endoremâ„¢ is taken up by macrophages, found only in healthy liver cells but not in most tumors. Tissues such as metastases, primary liver cancer, cysts and various benign tumors, adenomas and hyperplasia retain their native signal intensity, so the contrast between normal and abnormal tissue is increased.

See also Ferumoxide.

Eovist® (other brand name Primovist™) is a organ specific MRI contrast agent for the imaging, detection and characterization of liver conditions, including liver tumors, cysts, as well as other malignant and benign lesions. It is a water-soluble ethoxybenzyl derivative of Gd-DTPA. This compound is taken up by the hepatocytes (approximately 30% of the dose goes to the hepatocytes) and is equally excreted renal and biliary in humans. Excretion of Gd-EOB-DTPA in the bile may also permit visualization of both the gall bladder and the bile ducts.
Eovist® brightens the signal of T1 weighted MR images immediately after contrast administration. Dynamic and accumulation phase imaging can also be performed after bolus injection of Eovist®. The hepatocytes uptake will increase the signal intensity of normal liver parenchyma at 10 to 20 minutes after injection. This results in improved lesion-to-liver contrast because malignant tumors (metastases, the majority of hepatocellular carcinomas) do not contain either hepatocytes or their functioning is hampered.

WARNING: Gadolinium-based contrast agents increase the risk for nephrogenic systemic fibrosis (NSF) in patients with acute or chronic severe renal insufficiency (glomerular filtration rate less than 30 mL/min/1.73m²), or acute renal insufficiency of any severity due to the hepato-renal syndrome or in the perioperative liver transplantation period.

See also Drug Development and Approval Process USA, Contrast Medium, Hepatobiliary Contrast Agents, Tumor Specific Agents and Molecular Imaging.

(FRFSE, FR-FSE) The fast relaxation fast spin echo sequence provides high signal intensity of fluids even with short repetition times, and can be used with parallel imaging techniques for short breath hold imaging or respiratory gating for free-breathing, high isotropic resolution MR imaging. After signal decay at the end of the echo train, a negative 90° pulse align spins with long T2 from the transverse plane to the longitudinal plane, leading to a much faster recovery of tissues with long T2 time to the equilibrium and thus better contrast between tissues with long and short T2.
Fast relaxation FSE has advantages also for volumetric imaging as the TR can be substantially reduced and thus the scan time. The sequence can be post processed with maximum intensity projection, surface or volume rendering algorithms to visualize anatomical details in brain or spine MRI. Cerebro spinal fluid pulsation artifacts, often problematic in the cervical or thoracic spine may be reduced by radial sampling, in particular when combined with acquisitions of the PROPELLER type.

See also Fast spin echo, Driven Equilibrium.

A brand name for ferumoxide (same as Endoremâ„¢)
Feridex® is a sterile aqueous colloid of superparamagnetic iron oxide associated with dextran for intravenous administration as a MRI contrast medium for the detection of liver lesions that are associated with an alteration in the RES.
Feridex® is taken up by macrophages, found only in healthy liver cells but not in most tumors. Tissues such as metastases, primary liver cancer, cysts and various benign tumors, adenomas and hyperplasia retain their native signal intensity, so the contrast between normal and abnormal tissue is increased. Feridex® is a black to reddish-brown aqueous colloid.
See also Ferumoxide.

In November 2008, AMAG Pharmaceuticals, Inc. decided to discontinue the manufacturing of Feridex.