By: Constantino S.Peña
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When is MR Venography Useful? What makes it so Operator Dependent?
1. When is MR Venography Useful?
What makes it so Operator
Dependent ?
Constantino S.Peña
Interventional Radiologist
Medical Director, Vascular Imaging
Baptist Cardiac & Vascular Institute, Miami, Florida
Clinical Associate Professor of Medicine,
University of South Florida
And
Florida International University
Herbert Wertheim School of Medicine
2. Why MR Venography?
Evaluate Central Veins-
SVC, IVC, Pelvis
Patency and extrinsic compression
Allows for a 4 Dimensional Flow
evaluation- Time Resolved Imaging
Lack of Ionizing Radiation
Does not utilize Iodinated contrast
15. 4D Vascular MRA
Acquiring multiple 3D Volume datasets sequentially
Modified 3D Gradient sequence with parallel and/or
Keyhole imaging is used to achieve a high temporal
frame rate;
An initial mask is obtained
Morphology and time information acquired
Low dose of contrast agent used
22. Why is MR Venography
Operator Dependent?
What is the clinical question?
What is the best way to study?
What type of sequence and contrast
material?
24. Techniques for MRV
Indirect MRV- (recirculation)
Injecting upper extremity vein
Allowing first pass through the arterial
tree
Imaging venous system during venous
phase
Direct MRV
Injecting extremity of choice with dilute
contrast material
28. Future Technique
Direct Thrombus Imaging
Endogenous contrast from methemoglobin
T1W sequences
High signal seen up to 6months in DVT
Limitation in the abdomen (run additional PCV)
20 minutes whole body scan
29. When is CT Venography
better?
Evaluation of metal stent
Renal failure (Hemodialysis)
Pacemaker/AICD
30. Summary
MR Venography has a role in the diagnosis and
surveillance of “central venous” disease.
Indications include: SVC/IVC patency,
compressive syndromes, portal vein or visceral
vein patency. Usually performed when
treatment is being considered
MR Venography eliminates radiation risk
associated with CTV but is limited in terms of
heavy metal evaluation (bones and metal)
Off-label use of blood pool MR agents will
likely allow first pass as well as steady imaging
to improve resolution and evaluation of
compressive effects
Future MR imaging with Direct thrombus
imaging may deliver a manner to assess for
VTE without radiation or contrast agents