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Dr. McLafferty, discussed pathology such as acute venous disease, CVD, central venous pathology, pelvic congestion, nutcracker syndrome, venous malformations, & venous anomalies. Also discussed interventions utilized by venous specialists such as thrombolysis, PTA/stenting, embolization, ablation, filters, SEPS, sclerotherapy, surgery, & artificial venous valves
 
Dr. McLafferty, talked about imaging modalities such as non-invasive testing, duplex US, CT venography, MR venography, IVUS, venography (fluoroscopy, 3D recon, improved tech & devices)
 
Venography
Direct – Access axial vein of afflicted side, contrast directly to imaged vein
Indirect – Contrast in peripheral IV, IVÞ outflow veins Þ heart Þ arteries Þ capillaries Þ AXIAL VEINS
 
CT Venography
Advantages – Speed, x-rays from many angles/3D, readily available
Disadvantages – Iodinated contrast, ionizing radiation, streak artifact & static imaging
Multiple scans are sometimes needed due to different filling times
Without homogenous mixing, filling defects may occur
Under scrutinized for eval. Of venous anomalies
 
 
MRI Venography
Strong Magnate & aligns the molecules
RF pulse changes alignment
Signal detection
Signal processing
Gadolinium
Advantages – No ionizing radiation, non-contrast techniques, achieve high venous signal
Disadvantages – Acquisition time, metallic artifact
Contraindications – Pacemaker, claustrophobia, inability to lie still
 
Magnetic Resonance Imaging (MRI)
Used to diagnose arterial venous malformations such as Klippel Trenaunay Syndrome & Parkes Weber
Get a comprehensive view of anatomic distribution
Large clusters of varicose veins may be due to congenital or AV malformations
 
Dr. McLafferty shared many images such as May Thurner Syndrome, right internal jugular vein stenosis, etc…
 
CTV/MRV before ordering direct venography
Advantages:
Pre-intervention ‘road map’
Guide approach to access
Guide therapy plan
Duplex may fail
 
Multiple techniques are possible
Excellent visualization of adjacent structures
Multiple view planes are possible
Can view smaller veins
Reconstruction algorithms can lead to overestimation and false positives
 
Magnetic Resonance Venography (MRV)
2D time of flight MRV – Long acquisition times, sensitive to patient motions, flow changes-signal voids
 
Considerations
Low dose Gd-enhanced 3D MRV – Pedal vein infusion, good rapid distribution to extracellular space which allows greater contrast of tissue
 
Science behind MRV
Venous Enhanced Subtracted Peak Arterial Approach (VESPA)
Eight series of 3D MR angiographic data are acquired during bolus injection of a gadolinium-based contrast material. A pre-contrast data set and an arterial phase data set are subtracted from tow late (equilibrium phase) data sets to create a final 3D image that never really existed: a pure venogram.
 
 
Why should you do a CTV/MRV prior to direct venography?
Pre-intervention ‘Road map’
Thorough evaluation
Guide approach to access
Guide therapy plan
Duplex may fail (Abdomen/pelvis) (Wounds, obesity, edema)
 
Diagnosing venous malformations
Can diagnose/quantify compression syndromes
            Degree of compression
            Cause of compression
            Extent of thrombus
            Identify other pathology
            Your finding may change next treatment step
 
Finally, venous interventions requiring venography are on the rise
Consider ordering a CT/MRI as part of your evaluation
Know alternate imaging/treatments
Refer to interventional radiology if appropriate
 
 

Peggy Bush, APN

 

Bush Venous Lectures: www.bushvenouslectures.com

Vein Experts: www.veinexperts.com

Varicose Vein Consulting: www.vvcllc.com