With this magnetic resonance angiography technique flowing blood appears dark.
MR black blood techniques have been developed for cardiovascular imaging to improve segmentation of myocardium from the blood pool. Black blood MRA techniques decrease the signal from blood with reference to the myocardium and make it easier to perform cardiac chamber segmentation.
ECG gated spin echo sequences with presaturation pulses for magnetization preparation will show strong intravascular signal loss due to flow effects when appropriate imaging conditions including spatial presaturation are used. The sequence use the flow void effect as blood passes rapidly through the selected slice.
For dark blood preparation, a pair of nonselective and selective 180° inversion pulses are used, followed by a long inversion time to null signal from inflowing blood. A second selective inversion pulse can also be applied with short inversion time to null the fat signal. These in cardiac imaging used black blood techniques are referred to as double inversion recovery T1 measurement turbo spin echo or fast spin echo, and double-inversion recovery STIR.

Blood pool agents (intravascular contrast agents) remain in the blood for a prolonged time compared with conventional contrast agents, which diffuse quickly into the interstitial space. Magnetic resonance angiography (MRA), cardiovascular imaging, or contrast enhanced MRIs are possible over an hour or more. This advantage over conventional MRI contrast media allows also higher resolution MRA of several territories using respiratory or cardiac gating techniques with a single contrast bolus.
Different types of blood pool contrast agents:
Blood pool MRI contrast agents with their longer intravascular circulation can be designed to be targeted to necrotic myocardium, to assess myocardial viability, or tumor directed to provide better diagnostic information for various tumors. A disadvantage of the use of blood pool agents for MRA is that the separation of arteries and veins is more difficult because they are present in both and the overlapping of those vessels is disturbing. This can be solved by e.g. different MIP segmentation algorithms.

See also Necrosis Avid Contrast Agent, Tumor Specific Agents, Feruglose, Gadofosveset Trisodium (Vasovist), Ultrasmall Superparamagnetic Iron Oxide and Contrast Medium.

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Short name: Code 7228, generic name: Ferumoxytol, central moiety: Fe
Code 7228 is the code name for a substance in the development pipeline (AMAG Pharmaceuticals, Inc.) for use as a contrast agent in magnetic resonance angiography (MRA). Ferumoxytol, as a true blood pool agent, resides in the vascular space for an extended period of time and does not leak out into adjacent tissues like currently used gadolinium-based contrast agents. The product is being evaluated in MRA applications for the detection of blood flow in the heart muscle, in exploratory studies for the diagnosis of vulnerable plaque and as a next generation lymph node agent.
Code 7228 is currently in approval phase for use as an iron replacement therapeutic in chronic kidney disease patients receiving erythropoetin.
It is presently contemplated that Ferumoxytol will compete with the contrast agents Vasovist™ from EPIX Pharmaceuticals, Inc. and NC100150 Injection from Nycomed Amersham.

Combidex® is the brand name (same as Sinerem®) for an ultrasmall superparamagnetic iron oxide (USPIO) in the development pipeline to detect metastatic disease in lymph nodes. Metastatic lymph nodes show less uptake of this MRI contrast agent, which results in less signal decrease and allows the differentiation of normal lymph nodes from normal-sized, metastatic nodes. Combidex® has also potential to be used as a functional molecular imaging agent.
In March 2005, AMAG Pharmaceuticals Inc received an approvable letter from the U.S. Food and Drug Administration with respect to Combidex subject to certain conditions.
See also Ferumoxtran, Drug Development and Approval Process USA, Molecular Imaging and Classifications, Characteristics, etc.