Susceptibility weighted imaging

The Susceptibility imaging ( SWI ) (English susceptibility -weighted imaging, from Latin susceptibilitas " takeover capability") is an imaging technique in medical diagnostics, especially in the field of venous vessels. It is based on the physical property of the magnetic susceptibility.

SWI is a magnetic resonance imaging method. It uses flow-compensated, high spatial resolution 3D gradient echo (GRE ) sequence in single - and multi-echo technique utilizing the different magnetic susceptibilities of the various tissues. These differences lead to a phase difference (phase ) and cause a loss of signal ( magnitude ). There is no contrast agents. With the combination of the signal and phase images an enhanced image contrast signal is generated which venous blood ( brain ) hemorrhage and hemosiderin iron deposits such as radical.

The imaging of venous blood with SWI is called the blood - oxygen -dependent imaging ( BOLD, blood -oxygen -level dependent ). Venous ( deoxygenated ) blood is less diamagnetic than arterial ( oxygenated ) blood. The procedure was therefore initially replaced as BOLD denotes However, later by the more general term susceptibility contrast imaging. The term BOLD venography is nowadays sometimes still in use. Due to the BOLD effect, the venous system can be represented well with SWI.

SWI can be used in craniocerebral trauma with high-resolution Gehirnvenographien and other clinical applications. The underlying principle was first published in 1997 and 2001 described comprehensively.

Clinical Application

The clinical application is explored in various fields of medicine: Traumatic brain injury, stroke, cerebral amyloid angiopathy (CAA ), vascular malformations ( Sturge -Weber Syndrome, Cerebral venous sinus thrombosis), multiple sclerosis, Alzheimer 's disease and brain tumor.

Devices

SWI is integrated with newer Siemens appliances, but can a device-independent at field strengths of 1.0 T, 1.5 T, 3.0 T and higher are applied by appropriate software.

Historical development

In 1997, the basic process of removing interfering phase difference artifacts was developed under the preservation of local interesting phase difference. In 2001, the SWI underlying principle of E. Mark Haacke and Jürgen R. Reichenbach has been extensively described. J. Reichenbach has worked at the University of Jena in 1996.