ASL (Arterial Spin Labeling) is an application that allows perfusion imaging without the use of contrast agents. With this patent, Siemens will introduce syngo ASL, powered by TIM (Total Imaging Matrix). This will allow a broad range of users in both the clinical and research settings to get access to this promising application.

ASL is an MR technique that uses the water in arterial blood as an endogenous contrast agent to non-invasively evaluate perfusion. It provides unique insight into human brain perfusion and function physiology by evaluating cerebral blood flow (CBF). ASL is capable of high spatial resolution perfusion imaging, making the technique very appealing in the evaluation of stroke, tumors, degenerative diseases, and epilepsy, but also in basic neuroscience such as studies of functional CBF changes.

Initially, the techniques used for determining cerebral blood flow were quite invasive and involved using exogenous contrast agents like 150 labeled radiotracer in Positron Emission Tomography (PET). With MRI, brain perfusion studies have been commonly performed using exogenous Gadolinium-based contrast agents. The principles behind ASL are quite similar to those utilizing exogenous contrast agents. However, ASL is completely non-invasive, and there is no radiation and no injection of contrast media necessary.

The Siemens syngo ASL implementation benefits from the TIM technology by being integrated with Parallel Imaging that reduces the acquisition time. In addition, Siemens has integrated its unique 3D PACE motion correction technique, which increases robustness in clinical and research use.