Download Susceptibility Weighted Imaging

Susceptibility Weighted Imaging
Opening new doors to
clinical applications of
magnetic resonance imaging
4th Edition (2006)
E. Mark Haacke, PhD
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Susceptibility Weighted Imaging (SWI)
Creating New Insights in Neuro-Imaging
An Index to Clinical Applications of SWI
Diseases
• Occult Vascular Disease: Cavernomas, Angiomas, Telangiectasias
• Trauma in Both Adults and Children
• Stroke and Hemorrhage
• Hemorrhage and Sturge-Webber Disease
• Enhanced Detection of Tumors
• Multiple Sclerosis
• Differentiating Calcium from Veins
• Vascular Dementia and Cerebral Amyloid Angiopathy
Anatomical
• Small Vessel Imaging
• Labeling the Small Veins of the Brain
• Mineralization, Iron and Hemorrhage in the Basal Ganglia
• Phase Images of Motor Cortex and Dentate Nucleus
• Phase Images of the Mid-brain
Conventional T1
SWI
Images courtesy of Juergen Reichenbach, PhD,
Klinikum der Freidrich-Schiller-Univ, Jena, Germany
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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.
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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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).
Images courtesy of Karen Tong, MD, Loma Linda University, Loma Linda, CA
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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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. Juergen 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.
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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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).
Diffusion Weighted Image
A
B
SWI at 1.5T
D
C
Figure Caption:
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.
Images courtesy of Daniel Wycliffe, MD, Loma Linda University, Loma Linda, CA
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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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. Magn Reson Imaging
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.
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. Magn Reson Imaging
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: 10391042; 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.
Jürgen 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. Schad.
NMR in Biomedicine 14: 478-483; 2001.
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
Sturge-Webber Disease
Contrast enhanced T1
weighted imaging showing the
leptomeningeal enhancement
present in Sturge-Webber
disease.
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Post-contrast SWI showing a
markedly hypointense region
in the underlying white matter
that could reflect increased
deoxyhemoglobin, increased
local venous blood volume
and / or calcification.
Images courtesy of Jiani Hu, PhD, Jaladhar Neelavalli, MS, and Czabo Juhasz, MD, Wayne
State University, Detroit, MI
Detection of Hemorrhage in Tumors with SWI
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.
Images courtesy of Vivek Sehgal, MD, Wayne State University, Detroit, MI
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Published Research and Clinical Papers (Con’t)
13. High Resolution MR-Venography of Cerebral Arteriovenous Malformations. M.M.
Essig, J.R. Reichenbach, L.L. Schad, J.J. Debus, W.A. Kaiser. Radiologe 41: 288-95; 2001.
14. Improved Detection of Hemorrhagic Shearing Lesions in Children with Posttraumatic 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. Susceptibility Weighted Imaging. E.M. Haacke, Y. Xu, Y.N. Cheng, J.R. Reichenbach.
MRM 52:612-618; 2004.
18. L’Imagerie de Susceptibilite Magnetique: Theorie et Applications. D. Haddar, E.M.
Haacke, V. Sehgal, Z. DelProposto, G. Salamon, O. Seror, N. Sellier. J Radiol 85;1901-1908;
2004.
19. 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.
20. Susceptibility Weighted Imaging to Visualize Blood Products and Improve Tumor
Contrast in the Study of Brain Masses. V. Sehgal, Z. Delproposto, D. Haddar, E.M. Haacke,
A.E. Sloan, L.J. Zamorano, G. Barger, J. Hu, Y. Xu, K.P. Prabhakaran, I.R. Elangovan, J.
Neelavalli, J.R. Reichenbach. (Accepted for Publication at JMRI – Apr 2006).
21. Imaging Cerebral Amyloid Angiopathy with Susceptibility Weighted Imaging: A
Case Report. E.M. Haacke, V. Sehgal, Z. DelProposto, S. Chaturvedi, Z. Latif, D. KidoAJNR
(Accepted for publication at AJNR for a in February 2007).
22. 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.
23. 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.
24. Clinical Applications of Neuroimaging with Susceptibility Weighted Imaging. V.
Sehgal, Z. Delproposto, E.M Haacke, K. Tong, N. Wycliffe, D.K. Kido, Y. Xu, J. Neelavalli,
D. Haddar, J.R. Reichenbach. JMRI 22:439-450;2005.
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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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.
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.
Images courtesy of Daniel Kido, MD, Loma Linda University, Loma Linda, CA
An Occult Tumor Example
SWI shows nicely regions of
venous vascular content and
hemorrhage in the tumor not
seen with the conventional T1
weighted post-contrast scan.
SWI
T1 Post-Contrast
Images courtesy of Vivek Sehgal, MD, Wayne State University, Detroit, MI
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International Recognition of Susceptibility Weighted Imaging
The following awards have been made for research in SWI.
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
•
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)” Juergen 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
2002
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
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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.
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
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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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
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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.)
Images courtesy of Zach Del Proposto, MD, Wayne State University, Detroit, MI
T1-weighted image (left) and overlay of the SWI image on the T1 image (right), showing that CAA in this patient is ubiquitous in the parenchyma.
Images courtesy of Zach Del Proposto, MD, Wayne State University, Detroit, MI
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Current Ongoing Research Studies
•
A National Center of Excellence in Magnetic Resonance Imaging
Supported in part by the State of Michigan, Michigan Technology Tri-Corridor (MTTC) 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
•
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.
Professors:
Doctors:
Staff:
Professors:
Doctors:
Research Collaborators
Song Lai, Ewald Moser, Juergen Reichenbach, and Lothar Schad
Markus Barth and Frank Hoogenraad
Yingbiao Xu
Clinical Collaborators
Richard Briggs, Yulin Ge, Djamel Haddar, Daniel Kido, Meng Law, Vivek
Sehgal, Karen Tong, and Daniel Wycliffe
Zach Del Proposto
Finally, we point out that the name for this method has 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 (susceptibility weighted imaging). The
method is also sometimes referred to as BOLD MR Venography and when a contrast agent is
used contrast enhanced 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 effects such as the presence of hemosiderin or iron in the form of ferritin.
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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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.
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.
SWI at 4.0T
Compare the in-vivo SWI results
above to the radiologic images from
a cadaver brain shown on the right.
Image courtesy of Georges Salamon, MD, University of California Los Angeles (UCLA),
Los Angeles, CA
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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.
Prefrontal vein
Broca’s
Septal vein
Insula
Caudate
Supra marginal gyrus
S.long.sinus
Cingulate
gyrus
Thalamo striate
vein
Insular vein
Fronto
Lateral ventricle
temporal veins
Cingular & Internal
parietal veins
Images courtesy of Jay Gorell, MD, Henry Ford Hospital, Detroit, MI
Labeled figures courtesy of Georges Salamon, MD, UCLA, Los Angeles, CA
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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.
Conventional CT Scan
SWI at 1.5T
B
B
A
A
Mineralization in the globus
pallidus (barely seen in the
accompanying CT image).
Images courtesy of Daniel Kido, MD, Loma Linda University, Loma Linda, CA
Hypertension
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.
Images courtesy of Djamel Haddar, MD, Wayne State University, Detroit, MI
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Filtered Phase Image
Phase and Alzheimer’s
Disease
The use of 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
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.
B
A
SWI at 3.0T showing the dentate nuclei.
Image courtesy of Jay Gorell, MD, Henry Ford Hospital, Detroit, MI
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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.
4
3
1
2
5
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.
Image courtesy of E. Mark Haacke, PhD, Elena Manova, BS, and Muhammad Ayaz, MS,
Wayne State University, Detroit, MI
S USCEPTIBILITY W EIGHTED I MAGING (SWI)
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
SWI image at 3.0T post caffeine showing enhanced
Appointments:
venous visibility. Image courtesy of Todd Parrish, PhD
USA
Northwestern University, Chicago, IL
•
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