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Susceptibility Weighted Imaging Opening new doors to clinical applications of magnetic resonance imaging 5th Edition (2006) E. Mark Haacke, PhD

Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Page 1: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

Susceptibility Weighted Imaging

Opening new doors to clinical applications of

magnetic resonance imaging 5th Edition (2006)

E. Mark Haacke, PhD

Page 2: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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SUSCEPTIBILITY WEIGHTED IMAGING (SWI)

Images courtesy of Jürgen R. Reichenbach, PhD, Klinikum der Friedrich-Schiller-University, Jena, Germany

Occult Vascular Disease such as

Cavernomas, Angiomas,

Telangiectasias

Occult venous disease implies a change in

vascularity that is hard to find, sometimes even with the aid of a contrast agent.

Here we observe that the spider-like effect of this

angioma is easily seen with the SWI technique even

without a T1 reducing contrast agent.

SWI

Conventional T1

Susceptibility Weighted Imaging (SWI) Creating New Insights in Neuro-Imaging

An Index to Clinical Applications of SWI

Diseases

• Occult Vascular Disease: Cavernomas, Angiomas, Telangiectasias Page 2 • Trauma in Both Adults and Children Page 3 • Stroke and Hemorrhage Page 5 • Sturge-Weber Disease Page 7 • Enhanced Detection of Tumors Page 9 • Visualizing Oxygen Saturation in Tumors Page 11 • Imaging Tumors Page 13 • Differentiating Calcium from Veins Page 14 • Multiple Sclerosis Page 15 • Vascular Dementia and Cerebral Amyloid Angiopathy (CAA) Page 17

Anatomical

• Labeling the Small Veins of the Brain Small Vessel Imaging Page 18 • Small Vessel Imaging Page 19 • Mineralization, Iron and Hemorrhage in the Basal Ganglia Page 20 • Phase Images of Motor Cortex and Dentate Nucleus Page 21 • Phase Unwrapping Improves SWI Images Page 22 • Phase Images of the Mid-Brain Page 23

Page 3: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Images courtesy of Karen Tong, MD, Loma Linda University, Loma Linda, CA

Trauma for Both Adults and Children The detection of microhemorrhages, shearing and diffuse axonal injury (DAI) in trauma patients is difficult. Using SWI, we can see very small lesions. SWI is extremely sensitive to bleeding in the gray matter/white matter boundaries. Here, an example of purported DAI is shown compared to a conventional gradient echo image of the same area. Perhaps by following the resolution of hemorrhage in the brain, along with spectroscopic imaging, it may be possible to better monitor the internal improvement of trauma induced coma patients.

Diffuse axonal injury (top two images) and hemorrhage in a trauma case (bottom two images) acquired at 1.5T. Conventional gradient echo images with TE=20ms (2 left images) show a hint of hemorrhage inside the ventricles and slight white matter abnormalities. The SWI TE=40 ms images show clearly hemorrhage at the junction of white and gray matter (top right, arrows) and inside the ventricles and other areas (bottom right).

Page 4: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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SUSCEPTIBILITY WEIGHTED IMAGING (SWI)

Susceptibility Weighted Imaging* (also referred to as SWI**)

We have developed a new type of contrast in MRI different from spin density, T1, or T2 imaging. This new method exploits the susceptibility differences between tissues. We refer to this method as Susceptibility Weighted Imaging*. SWI** uses a fully velocity compensated, three dimensional, rf spoiled, high-resolution, 3D gradient echo scan. Signal from substances with different susceptibilities than their neighboring tissues (such as venous blood, or hemorrhage, for example) can manifest contrast in these ways: first, tissues with different susceptibilities can be differentiated as phase filtered SWI images alone; second, the signal from objects smaller than a voxel will beat against that of its neighbor creating a powerful partial volume effect, and third phase and magnitude can be combined to absorb both effects. SWI can be run on any manufacturer’s machine at field strengths of 1.0T, 1.5T, 3.0T and higher.

SWI is a unique combination of some or all of the following features: • High resolution 3D gradient echo imaging • Full flow compensation in all three directions • Thin slices to avoid signal losses • Filtering of phase images to reduce unwanted field effects • Creating a phase mask image • Operating on the magnitude image with the phase mask • Taking a minimum intensity projection over neighboring slices

This special data acquisition and image processing produces an enhanced contrast magnitude image which is exquisitely sensitive to venous blood, hemorrhage and iron storage. SWI offers you the potential for: • Better diagnosis of disease • Better follow up for longitudinal studies • An opportunity to be involved in the clinical evaluation of a new concept • An opportunity to open new doors in clinical MRI *The mechanisms behind susceptibility weighted imaging are protected via US Patent 6,501,272 B1 issued 31 December, 2002. Dr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also has another patent on both data collection and processing aspects of SWI via US Patent 6,658,280 B1 issued 2 December 2003. **SWI is a trademark approved term for Susceptibility Weighted Imaging.

Page 5: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Images courtesy of Daniel Wycliffe, MD, Loma Linda University, Loma Linda, CA

Diffusion Weighted Image

SWI at 1.5T

A

B

C D

The bright region in the diffusion weighted image shows the area affected in this acute stroke example. The arrows in the SWI image may show the tissue at risk that has been affected by the stroke (A, B, C) and the location of the stroke itself (D). The reason that we are able to see the affected vascular territory could be because there is a reduced level of oxygen saturation in this tissue, suggesting that the flow to this region of the brain could be reduced post stroke. Another possible explanation is that there is an increase in local venous blood volume. In either case, this image suggests that the tissue associated with this vascular territory could be tissue at risk. Future stroke research will involve comparisons of perfusion weighted imaging and SWI to learn more about local flow and oxygen saturation.

Stroke and Hemorrhage Diffusion weighted imaging offers a powerful means to detect acute stroke. Although it is well known that gradient echo imaging can detect hemorrhage, it is best detected with SWI. In the example shown here, the diffusion image shows the region of likely cytotoxic edema whereas the SW image shows the likely localization of the stroke and the vascular territory affected (data acquired at 1.5T).

Page 6: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Published Research and Clinical Papers 1. Small Vessels in the Human Brain: MR Venography with Deoxyhemoglobin as an Intrinsic Contrast Agent. J.R. Reichenbach, R. Venkatesan, D.J. Schillinger, D.K. Kido, E.M. Haacke. Radiology 204; 272-277; 1997. 2. High-Resolution Venography of the Brain Using Magnetic Resonance Imaging. J.R. Reichenbach, M. Essig, E.M. Haacke, B.C. Lee, C. Przetak, W.A. Kaiser, L.R. Schad. MAGMA 6; 62-69; 1998. 3. Comparison of Functional Venography and EPI-BOLD-fMRI at 1.5T . K.T. Baudendistel, J.R. Reichenbach, R. Metzner, J. Schröder, L.R. Schad. MRI 16; 989-991; 1998. 4. MR High-Resolution Blood Oxygenation Level - Dependent Venography of Occult (Low-Flow) Vascular Lesions. B.C.P. Lee, K.D. Vo, D.K. Kido, P. Mukherjee, J. R. Reichenbach, W. Lin, M.S. Yoon, E.M. Haacke. AJNR 20; 1239-1242; 1999. 5. High-Resolution MR Venography of Cerebral Arteriovenous Malformations. M. Essig, J.R. Reichenbach, L.R. Schad, S.O. Schönberg, J. Debus, W.A. Kaiser. MRI 17; 1417-1425; 1999. 6. Spatial Selectivity of BOLD Contrast: Effects In and Around Draining Veins. S. Lai, G.H. Glover, E.M. Haacke. Chapter 20 in Medical Radiology. Diagnostic Imaging and Radiation Oncology, Eds. C.R.W. Moonen, P.A. Bandettini. Springer-Verlag 1999. 7. Improving High-Resolution MR Bold Venographic Imaging Using a T1 Reducing Contrast Agent. W. Lin, P. Mukherjee, H. An, Y. Yu, Y. Wang, K. Vo, B. Lee, D. Kido, E.M. Haacke. JMRI 10; 118-123; 1999. 8. High-Resolution MR Venography at 3 Tesla. J.R. Reichenbach, M. Barth, E.M. Haacke, M. Klarhöfer, W.A. Kaiser, E. Moser. JCAT 24; 949-957; 2000. 9. MR Venography of Multiple Sclerosis. I.L. Tan, R.A. van Schijndel, P.J.W. Pouwels, M.A.A. van Walderveen, J.R. Reichenbach, R. A. Manoliu and F. Barkhof. AJNR 21: 1039-1042; 2000. 10. High-resolution Blood Oxygen-Level Dependent MR Venography (HRBV): A New Technique. J.R. Reichenbach, L. Jonetz-Mentzel, C. Fitzek, E.M. Haacke, D.K. Kido, B.C.P. Lee, W.A. Kaiser. Neuroradiology 43: 364-369; 2001. 11. High-Resolution BOLD Venographic Imaging: A Window into Brain Function. J.R. Reichenbach, E. M. Haacke. NMR in Biomedicine 14: 453-467; 2001. 12. Improved Target Volume Characterization in Stereotactic Treatment Planning of Brain Lesions by Using High-Resolution BOLD MR-Venography. L.R. Schad. NMR in Biomedicine 14: 478-483; 2001.

Page 7: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Images courtesy of Jiani Hu, PhD, Jaladhar Neelavalli, MS, and Czabo Juhasz, MD, Wayne State University, Detroit, MI

Post-contrast SWI showing a markedly hypointense region in the underlying white matter that cou ld r e f l ec t i nc r ea sed deoxyhemoglobin, increased local venous blood volume and/or calcification.

Sturge-Weber Disease

Contrast enhanced T1 weighted i m a g i n g s h o w i n g t h e leptomeningeal enhancement present in Sturge-Weber disease.

A venogram of a neonate with Sturge-Weber syndrome who did not

display neurological symptoms and where the initial conventional MR

imaging methods did not demonstrate any abnormality. The abnormal

venous vasculature in the left occipital lobe extending between the

posterior horn of the ventricle and the cortical surface is clearly visible in

the venogram. Due to the high resolution even collaterals can be

resolved.

(Image courtesy of Alexander Rauscher, Jan Sedlacik, Andreas

Deistung, Hans-Joachim Mentzel, Jürgen R. Reichenbach, FSU Jena,

Germany.)

Page 8: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Published Research and Clinical Papers (Con’t)

13. High Resolution MR-Venography of Cerebral Arteriovenous Malformations. M. Essig, J.R. Reichenbach, L.R. Schad, J.J. Debus, W.A. Kaiser. Radiologe 41: 288-95; 2001. 14. Improved Detection of Hemorrhagic Shearing Lesions in Children with Post-traumatic Diffuse Axonal Injury-Initial Results. K.A. Tong, S. Ashwal, B.A. Holshouser, L. Shutter, G. Herigault, E.M. Haacke, D.K. Kido. Radiology 227: 332-339; 2003. 15. Enhanced BOLD MR-Venography (CE-MRV) of Brain Tumors at 3 Tesla: First Clinical Experience. M. Barth, I.M. Nobauer-Huhmann, J.R. Reichenbach, V. Mlynarik, A. Schoggl, C. Matula, S. Trattnig. Investigative Radiology 38:409-414; 2003. 16. Automated Unwrapping of MR Phase Images Applied to BOLD MR-Venography at 3 Tesla. A. Rauscher, M. Barth, J.R. Reichenbach, R. Stollberger, E. Moser. JMRI 18:175–180; 2003. 17. MR imaging visualization of the cerebral microvasculature: a comparison of live and postmortem studies at 8 T. R.A. Dashner, D.W. Chakeres, A. Kangarlu, P. Schmalbrock, G. A. Christoforidis, R.M. DePhilip . AJNR 24:1881-1884; 2003. 18. Susceptibility Weighted Imaging. E.M. Haacke, Y. Xu, Y.N. Cheng, J.R. Reichenbach. MRM 52:612-618; 2004. 19. L’Imagerie de Susceptibilite Magnetique: Theorie et Applications. D. Haddar, E.M. Haacke, V. Sehgal, Z. Del Proposto, G. Salamon, O. Seror, N. Sellier. J Radiol 85;1901-1908; 2004. 20. Imaging Iron Stores in the Brain using Magnetic Resonance Imaging. E.M. Haacke, N.Y.C. Cheng, Q. Liu, J. Neelavalli, Robert Ogg, A. Khan, M. Ayaz, W. Kirsch, A. Obenaus. MRI 23:1–25; 2005. 21. Noninvasive Assessment of Vascular Architecture and Function During Modulated Blood Oxygenation Using Susceptibility Weighted MRI (SWI). A. Rauscher , J. Sedlacik, M. Barth, E.M. Haacke, J.R. Reichenbach. MRM 54: 87-95; 2005.

22. High resolution susceptibility weighted MR-maging of brain tumors during the application of a gaseous agent. A. Rauscher, J. Sedlacik, C. Fitzek, B. Walter, A. Hochstetter, R. Kalff, W.A. Kaiser, J.R. Reichenbach. Rofo. 177(8):1065-9; 2005

23. Magnetic Susceptibility Sensitive MR Phase Imaging of the Human Brain. A. Rauscher, J. Sedlacik, M. Barth, H-J. Mentzel, J.R. Reichenbach. AJNR 26:736 742; 2005.

Page 9: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Images courtesy of Daniel Kido, MD, Loma Linda University, Loma Linda, CA

T1 Post-Contrast SWI

SWI often shows the location of the draining veins

in the tumor rather than the diffuse contrast usually seen

with conventional T1 post contrast scans.

Enhanced Detection of Tumors The development of susceptibility weighted imaging (SWI) has opened the door for improved contrast and improved detection of hemorrhage in tumors. Part of the characterization of tumors lies in understanding the angiographic behavior of lesions both from the perspective of angiogenesis and micro - hemorrhages. Aggressive tumors tend to have rapidly growing vasculature and many microhemorrhages. Hence, our ability to detect these changes in the tumor could lead to a better determination of the tumor status. The enhanced sensitivity of SWI to venous blood and blood products due to their differences in susceptibility compared to normal tissue leads to better contrast in detecting tumor boundaries and tumor hemorrhage.

An Occult Tumor Example

Images courtesy of Vivek Sehgal, MD, Wayne State University, Detroit, MI

SWI

T1 Post-Contrast

SWI shows nicely regions of venous vascular content and

hemorrhage in the tumor not seen with the conventional T1 weighted

post-contrast scan.

Page 10: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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SUSCEPTIBILITY WEIGHTED IMAGING (SWI)

Published Research and Clinical Papers (Con’t)

24. Early diagnosis of cerebral involvement in Sturge-Weber syndrome using high-resolution BOLD MR venography. H.-J. Mentzel, A. Dieckmann, C. Fitzek, U. Brandl, J.R. Reichenbach, W.A. Kaiser. Pediatr. Radiol. 35(1):85-90; 2005.

25. Clinical Applications of Neuroimaging with Susceptibility Weighted Imaging. V. Sehgal, Z. Del Proposto, E.M Haacke, K. Tong, N. Wycliffe, D.K. Kido, Y. Xu, J. Neelavalli, D. Haddar, J.R. Reichenbach. JMRI 22:439-450; 2005. 26. The Role of Voxel Aspect Ratio in Determining Apparent Phase Behavior in Susceptibility Weighted Imaging. Y. Xu, E.M. Haacke. MRI 24:155-160; 2006. 27. Contrast-enhanced, High-resolution, Susceptibility-weighted MR Imaging (CE-SWI) of the Brain: Dose-dependent Optimization at 3 Tesla and 1.5 Tesla in Healthy Volunteers. I-M. Noebauer-Huhmann, K. Pinker, M. Barth, V. Mlynarik, A. Ba-Ssalamah, W. Saringer, M. Weber, T. Benesch, S. Witoszynskyj, A. Rauscher, J. R. Reichenbach, S. Trattnig. Invest Radiol. 41:249-55; 2006 28. Imaging Cerebral Amyloid Angiopathy with Susceptibility Weighted Imaging: A Case Report. E.M. Haacke, V. Sehgal, Z. Del Proposto, S. Chaturvedi, Z. Latif, D. Kido. AJNR (Accepted for publication at AJNR to appear in February 2007).

A Little Bit of History about the Nomenclature for SWI

The name for Susceptibility Weighted Imaging (SWI) evolved from HRBV (high resolution BOLD venographic imaging) to AVID BOLD (applications of venous imaging in detecting disease) to the simpler and more generic acronym SWI. The method is also sometimes referred to as BOLD MR Venography (MRV) and when a contrast agent is used contrast enhanced (CE) MRV. However, one might consider HRBV, MRV or AVID BOLD (which all refer to the same method) as a subset of SWI focusing on veins only, whereas SWI can visualize other susceptibility effects such as the presence of hemosiderin or iron in the form of ferritin. Today SWI can refer to the processed and mIPped magnitude SWI images as well as the SWI filtered phase images which in and of themselves are important. The latter can also be mIPped to view those areas of tissue susceptibility changes across many slices.

Page 11: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Venogram of a tumor patient with the overlaid SWI signal increase during carbogen breathing. Tumor response to carbogen breathing is spatially heterogeneous with an inactive necrotic tumor center (long arrow) and an active periphery (short arrows). Image courtesy of Alexander Rauscher, Jürgen R. Reichenbach, FSU Jena, Germany.

Images courtesy of Alexander Rauscher, Jan Sedlacik, Jürgen R. Reichenbach, FSU Jena, Germany.

Visualizing Oxygen Saturation in Tumors

Cerebral blood flow changes caused by exogenous substances have an impact on the oxygenation level of venous blood. These changes can be detected with the help of SWI. Regions with unusual blood supply, like brain tumors, aneurysms and ischemia, can be characterized and separated from healthy tissue. Breathing normal air has a better visualization of the veins (left image) than breathing oxygen (middle image) because of the higher de-oxyhemoglobin lack. On the other hand, carbogen (5% CO2, 95% O2) breathing induces an increase in venous blood oxygenation which leads to a reduction of field inhomogeneities around the vessels. Consequently, the contrast between veins and surrounding parenchyma is reduced (right image).

Page 12: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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International Recognition of Susceptibility Weighted Imaging

1998 • Marie-Sklodowska-Curie Prize “Visualization of Cerebral Venous Structures Using High

Resolution MRI” J.R. Reichenbach, L.R. Schad, M. Essig, E.M. Haacke, W.A. Kaiser

2000 • Poster Prize of the XXVI Congress of European Society of Neuroradiology 2000

"High-Resolution Blood Oxygen Level Dependent MR Venography" J.R. Reichenbach, L. Jonetz-Mentzel, C. Fitzek, H.J. Mentzel, E.M. Haacke, W.A. Kaiser. ESNR 2000 XXVI Congress and XI Advanced Course, September 10-13, 2000, Oslo, Norway

2002 • The ECR 2002 European Congress of Radiology: Scientific Exhibition Award ECR

2002 Cum Laude "Clinical Applications of High-Resolution BOLD Venography" J.R. Reichenbach, C. Fitzek, L. Jonetz-Mentzel, D. Sauner, H.J. Mentzel, E.M. Haacke, W.A. Kaiser. ECR 2002 European Congress of Radiology, March 1-5, 2002, Vienna, Austria. Eur Radiol 2002; 12(2), Suppl. 1:459

• The ECR 2002 Research & Education Fund: Nycomed Amersham Research Fellowship Grant "High-Resolution Venographic BOLD Imaging of the Human Brain and Its Application to Brain Lesions" J.R. Reichenbach. ECR 2002 European Congress of Radiology, March 1-5, 2002, Vienna, Austria

• The German Röntgen Society awarded the Walter-Friedrich-Award “High Resolution

Angiography of the Human Brain-Development and Trial of a New Method of Magnetic Resonance Tomography (BOLD-Angiography)” Jürgen R. Reichenbach's Habilitation

• The Derek Harwood-Nash Award for the Best Paper in Pediatric Neuroradiology was

presented by the American Society of Pediatric Neuroradiology at the Annual Meeting in Vancouver, Canada "Improved Detection of Hemorrhagic Shearing Injuries in Children with Post-Traumatic Diffuse Axonal Injury Using Susceptibility Weighted Imaging: Correlation with Severity and Outcome" Karen A. Tong, MD

2004 • The 2004 International Society of Magnetic Resonance in Medicine (ISMRM) Gold

Medal Award for Significant Contribution to Research in the Field of Magnetic Resonance in Medicine, Biology, and Related Fields awarded to E.M. Haacke, PhD. 12th Annual ISMRM, May 15-21, 2004, Kyoto, Japan

• The 2004 Toshiba Research Award of the German Society for Medical Physics

(Deutsche Gesellschaft für Medizinische Physik, DGMP) for the paper Non invasive Assessment of Vascular Architecture and Function During Modulated Blood Oxygenation Using Susceptibility Weighted MRI awarded during the 35th Annual Meeting to Alexander Rauscher, PhD

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Images courtesy of Vivek Sehgal, MD, Wayne State University, Detroit, MI

A pre-contrast T1 weighted scan of a brain metastasis which doesn’t show any hint of hemorrhage.

Using the SWI method, there is evidence of blood products which have been confirmed by pathology.

Detection of Hemorrhage in Tumors with SWI

Identifying Tumor Boundaries with SWI

There is some evidence that the boundaries of the SWI of tumors may be an indication of an increase in vascular content in those areas. An example is given below that shows a very poorly defined large tumor pre-contrast injection T1 weighted image followed by the SW image. The dark boundaries appear to predict where the tumor will enhance (arrows). Sure enough this is almost exactly where we see the bright edges in the post-contrast T1 weighted image.

Left hand side - pre-contrast T1 weighted image; Middle - SWI; Right hand side - post-contrast T1 weighted image. Arrows indicate boundaries seen with SWI without a contrast agent that then appear to predict the enhancement seen post-contrast.

Page 14: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Differentiating Calcium from Veins Calcium is difficult to differentiate from blood in either CT or MRI. However, in SWI, the phase of calcium is opposite to that of hemorrhage or veins. The dark spots in the SWI filtered phase image in the tumor region are believed to be calcium. Contrast this to the bright signal in the phase from veins (note Siemens uses a left handed system which means that paramagnetic material will have a positive phase). Biopsy has shown that this lesion contains high levels of calcium.

CT SWI Magnitude

CT SWI Filtered Phase

Images courtesy of Jiani Hu, PhD, Wayne State University, Detroit, MI

Top left and bottom left: CT image showing calcifications in the tumor. Top right: magnitude SWI image. Bottom right: SWI filtered phase image.

Page 15: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Multiple Sclerosis Multiple Sclerosis (MS) is usually studied with FLAIR and contrast enhanced T1 imaging. However, SWI reveals not only the venous connectivity in some lesions but also presents evidence of iron in some lesions. This key new information may help understand the physiology of MS. The SWI filtered phase images shown below were acquired at 3T.

Images courtesy of E. Mark Haacke, PhD, Wayne State University, Detroit, MI. Data courtesy of Yulin Ge, MD and Meng Law, MD, New York University, New York, NY.

SWI appears to add at least seven (7) new perspectives to imaging MS. Specifically, SWI sees lesions:

• connected by vessels • with dark centers • not seen with FLAIR • with iron deposition • of the gray matter

Also, we find that there are lesions: • seen on FLAIR but not on SWI

and that there is: • increased iron in the basal ganglia

Page 16: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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SUSCEPTIBILITY WEIGHTED IMAGING (SWI)

Current Ongoing Research Studies • A National Center of Excellence in Magnetic Resonance Imaging

Supported in part by the State of Michigan - Grant #085P5200251 • Neural Correlates and Modifiers of Cognitive Aging

Supported in part by the National Institutes of Health - Grant #AG011230 • The Role of SWI in High Resolution fMRI Studies

Supported in part by the National Institutes of Health - Grant #HL62983 • Iron Metabolism Alterations in Alzheimer’s Disease

Supported in part by the National Institutes of Health - Grant #AG20948 • Clinical Implementation of SWI

Supported in part by Siemens Medical Solutions, Inc.

• Improved Characterization of Tumors in MRI Using SWI National Institutes of Health Grant, In Review

• Development and validation of new methods for the non-invasive assessment of the venous architecture at high spatial resolution using SWI Jürgen R. Reichenbach; German Research Foundation (DFG, RE 1123/7-1 and 7-2)

• Development and validation of an MR-method for the non-invasive measurement of

cerebral physiological parameters at high spatial resolution. Alexander Rauscher, Jürgen R. Reichenbach, Interdisciplinary Center for Clinical Studies (IZKF) Jena, Germany; Start-up Grant S10

• Detecting Hemorrhage and Diffuse Axonal Injury in Trauma

National Institutes of Health Program Project Grant, In Preparation

References to Research Papers Using SWI We wish to thank all those involved in what can only be called a major international collaboration by the following people, to whom goes my utmost thanks and appreciation for their participation in and promotion of this research and its clinical applications.

Research Collaborators Professors: Markus Barth, Song Lai, Ewald Moser, Jürgen R. Reichenbach, and Lothar R. Schad Doctors: Alexander Rauscher and Frank Hoogenraad Staff: Jan Sedlacik and Yingbiao Xu

Clinical Collaborators Professors: Richard Briggs, Yulin Ge, Djamel Haddar, Daniel Kido, Meng Law, Vivek Sehgal, Karen Tong, and Daniel Wycliffe Doctors: Zach Del Proposto

Page 17: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Vascular Dementia and Cerebral Amyloid Angiopathy (CAA) Conventional gradient echo T2*-weighted image (left, TE=20ms) resolution shows some low-signal foci associated with CAA. On the other hand, SWI image (center, with a resolution of 0.5mm x 0.5mm x 2.0mm, projected over 8mm) shows many more associated low-signal foci. Phase images were used to enhance the effect of the local hemosiderin build up. An example phase image (right) with yet higher resolution of 0.25mm x 0.25mm x 2.0mm shows a clear ability to localize multiple CAA-associated foci. (All images collected on a Siemens 1.5T Sonata.)

T1-weighted image (left) and overlay of the SWI image on the T1 image (right), show-ing that CAA in this patient is ubiquitous in the parenchyma.

Images courtesy of Zach Del Proposto, MD, Wayne State University, Detroit, MI

Images courtesy of Zach Del Proposto, MD, Wayne State University, Detroit, MI

Page 18: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Images courtesy of Jay Gorell, MD, Henry Ford Hospital, Detroit, MI Labeled figures courtesy of Georges Salamon, MD, UCLA, Los Angeles, CA

Insula Broca’s

Supra marginal gyrus

Caudate

Lateral ventricle

Cingulate gyrus

Septal vein

Insular vein

Prefrontal vein

Thalamo striate vein

Cingular & Internal

parietal veins

Fronto

temporal veins

S.long.sinus

The Advantages of High Field SWI The images from higher field strengths are generally of higher quality than the lower field strengths because of the increased SNR. The higher the field strength, the better the results, the better the signal-to-noise, and the better the coverage in a fixed period of time. On the other hand, we can trade-off signal-to-noise to obtain even higher resolution. Here we show an example from a General Electric 3T system where the vessels are now labeled; these images serve as an important educational tool. Vascularization at the level of: Caudate, Striatum, Orbito-frontal, and Temporo-parietal areas.

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Small Vessel Imaging Imagine the ability to image vessels smaller than a voxel, as small as deep white matter vessels. With SWI this is now possible for venous blood. Using 1.5T systems you can visualize veins on the order of a few hundred microns with 1 mm3 resolution in imaging times of roughly 5 to 10 minutes. Using 3.0T or 4.0T systems, imaging time can be reduced or resolution increased to create images competitive to radiologic cadaver brain images.

Image courtesy of Georges Salamon, MD, University of California Los Angeles (UCLA), Los Angeles, CA

Exquisite representation of small veins in the brain for both the medial and peripheral drainage systems in the brain.

Data courtesy of Yingbiao Xu, Wayne State University, Detroit, MI. Processing performed using SPIN software from the MRI Institute for Biomedical Research.

Compare the in-vivo SWI results above to the radiologic images from a cadaver brain shown on the right.

SWI at 4.0T

Page 20: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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SUSCEPTIBILITY WEIGHTED IMAGING (SWI)

Mineralization, Iron and Hemorrhage in the Basal Ganglia The standard method to evaluate mineralization in the basal ganglia has been using Computed Tomography (CT). Now SWI offers a more sensitive means to pick up abnormalities in iron and calcium in these regions.

Images courtesy of Daniel Kido, MD, Loma Linda University, Loma Linda, CA

Conventional CT Scan

A

Mineralization in the globus pallidus (barely seen in the ac-companying CT image).

An example of hemorrhages in the

basal ganglia and other parts of the brain. SWI can show effects on the

order of a few cubic millimeters.

Hypertension

B A B

Images courtesy of Djamel Haddar, MD, Wayne State University, Detroit, MI

SWI at 1.5T

Page 21: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Phase and Alzheimer’s Disease

The use of SWI filtered phase images can show not only the presence of veins and hemorrhage but also may be an indicator of iron content (see arrows highlighting the motor cortex). The contrast between the gray matter and the CSF or white matter is presumably due to the increased iron content in the gray matter. It is thought that iron around beta amyloid plaque or other sources of iron may be an indication of the early development of Alzheimer’s disease. This image was collected at 3.0T at Northwestern University.

Image courtesy of E. Mark Haacke, PhD, Wayne State University, Detroit, MI

Dentate Nucleus

SWI Filtered Phase Image

After filtering the phase, it becomes possible to see contrast between iron laden tissues and surrounding tissues. Here we see the contrast not otherwise visible on the T1 weighted images. The arrows show (A) the dentate nucleus and (B) the right cerebellar hemisphere.

Image courtesy of Jay Gorell, MD, Henry Ford Hospital, Detroit, MI

SWI at 3.0T showing the dentate nuclei.

A

B

Phase Imaging SWI was originally developed with the aim to visualize the cerebral venous architecture by exploiting both the magnitude and phase information. However, the pure phase images also contain a wealth of information that may not be assessed using the magnitude images or the SWI venograms. Phase changes induced by different tissue iron content, for instance, lead to good image contrast in phase imaging. By appropriately processing the phase images to remove background field effects, local tissue susceptibility can be enhanced in what we refer to as "SWI filtered phase images". These can be viewed and mIPped similar to the usual SWI magnitude processed images.

Page 22: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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SUSCEPTIBILITY WEIGHTED IMAGING (SWI)

Images courtesy of Stephan Witoszynskyj, Alexander Rauscher, Jürgen R. Reichenbach, and Markus Barth, FSU Jena (Germany) and FC Donders Centre for Cognitive Neuroimaging, Nijmegen (The Netherlands).

Unwrapped and SWI high pass filtered phase image. Heme (veins) and non-heme iron (basal ganglia) produce good image contrast and even the thalamic nuclei and the substructure of the striata can be identified. Image courtesy of Alexander Rauscher, Jan Sedlacik, Andreas Deistung, Hans-Joachim Mentzel, Jürgen R. Reichenbach, FSU Jena, Germany.

Unwrapping Improves SWI Images

Susceptibility weighted image generated with homodyne filtering (left) and improved phase unwrapping (right) in image space. Strong field gradients in the frontal area lead to artifacts in venograms processed with the usual homodyne filtering. These do not appear in the venogram generated with phase unwrapping applied prior to homodyne filtering.

Page 23: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

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Phase Images of the Mid-Brain SWI filtered phase images reveal subtle variations in iron content in the human midbrain. This new contrast mechanism observed here at 1.5T even predicts where reductions in T2* occur at high field and hence predict contrast seen at high field. Further, the iron content seen here corresponds to vascular density or seen in India Ink stained cadaver brain studies suggesting a natural affiliation of iron and the vascular network.

Image courtesy of E. Mark Haacke, PhD, Elena Manova, BS, and Muhammad Ayaz, MS, Wayne State University, Detroit, MI

4

2 1

5

3

1. Red Nucleus 2. Substantia Nigra, Pars Compacta 3. Substantia Nigra, Pars Reticulata

4. Crus Cerebri 5. Medial Geniculate

Recent research also suggests that such iron depositions are associated with the vasculature, especially in elderly patients. This iron may correspond to hemosiderin from the ongoing presence of micro-hemorrhaging in the aging process.

Page 24: Susceptibility Weighted ImagingDr. E. Mark Haacke is the primary inventor of SWI along with his fellow co-inventors both Dr. Jürgen R. Reichenbach and Dr. Yi Wang. Dr. Haacke also

For more information about:

Susceptibility Weighted Imaging

contact:

Name: E. Mark Haacke, PhD*

Email: [email protected]

Tel: 313-745-1395

Tel: 313-758-0065

Website: http://www.swi-mri.com

Appointments:

USA

• Professor of Radiology and Biomedical Engineering Wayne State University, Detroit, Michigan

• Professor of Radiology

Loma Linda University, Loma Linda, California

• Professor of Physics

Case Western Reserve University, Cleveland, Ohio

CANADA

• Professor of Electrical and Computer Engineering

McMaster University, Hamilton, Ontario

*Dr. Haacke is the Director of:

• The MR Research Facility at Wayne State University, Detroit, Michigan, USA

• The MRI Institute for Biomedical Research in Detroit, Michigan, USA

• The Imaging Laboratory of the School of Biomedical Engineering at McMaster University, Hamilton, Ontario, CANADA

SWI image at 3.0T post caffeine showing enhanced

venous visibility. Image courtesy of Todd Parrish, PhD

Northwestern University, Chicago, IL