What is arterial spin labeling perfusion?

Arterial spin labeling ( ASL ) is a magnetic resonance (MR) imaging technique that enables the measurement of brain perfusion noninvasively at the tissue level. Benefiting from the contrast of inflowing magnetically labeled blood, ASL obviates an exogenous contrast agent.

Can arterial spin labeling detect white matter perfusion signal?

Since the invention of arterial spin labeling (ASL) it has been acknowledged that ASL does not allow reliable detection of a white matter (WM) perfusion signal. However, recent developments such as pseudo-continuous labeling and background suppression have improved the quality.

How does arterial spin Labelling work?

Arterial spin labelling utilizes the water molecules circulating with the brain, and using a radiofrequency pulse, tracks the blood water as it circulates throughout the brain. After a period of time in microseconds (enough to allow the blood to circulate through the brain), a ‘label’ image is captured.

What is perfusion sequence in MRI?

Perfusion MRI or perfusion-weighted imaging (PWI) is perfusion scanning by the use of a particular MRI sequence. The acquired data are then post-processed to obtain perfusion maps with different parameters, such as BV (blood volume), BF (blood flow), MTT (mean transit time) and TTP (time to peak).

How is arterial spin labeling ( ASL ) used in MRI?

Synopsis Arterial spin labeling (ASL) will soon be available as a routine clinical perfusion imaging sequence for a significant number of MRI scanners. The ASL perfusion technique offers similar information as conventional dynamic susceptibility sequences; however, it does not require intravenous contrast and can be quantified.

How is arterial spin labeling MR perfusion used?

It is a non-invasive and non-ionising MRI technique that measures tissue perfusion (blood flow), by using magnetically-labeled arterial blood water protons as an endogenous tracer. ASL is a very suitable technique to use pediatrics, in which the use of radioactive tracers may be restricted.

How is magnetic labeling used in ASL perfusion?

A number of techniques have been described to achieve ASL perfusion, classified based on the magnetic labeling process 2: The main idea in ASL is to obtain a labeled image or tagged image and a control image, in which the static tissue signals are identical but the magnetization of the inflowing blood is different.

How does an MRI measure cerebral blood flow?

Instead it exploits the ability of MRI to magnetically label arterial blood below the imaging slab. The parameter most commonly derived is cerebral blood flow (CBF) . It is a non-invasive and non-ionizing MRI technique that measures tissue perfusion (blood flow), by using magnetically-labeled arterial blood water protons as an endogenous tracer.