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ACP Annual Congress 2016 Mel Rosenblatt, M.D. FACPh Connecticut Image Guided Surgery Disclosures I have no pertinent disclosures related to the material that will be presented Venography Introduction • Venography is the oldest venous imaging tool • Newer non invasive imaging modalities have supplanted venography as a diagnostic tool • CT/CTV (direct or indirect) • MRI/MRV • IVUS • Despite it’s age venograpjy still has value and basic interpretation skills are neccessary • In the modern age what is the role of venography? Venography What is it’s Role? • Diagnostic • Venography is rarely used as a diagnostic tool alone • Can be used to diagnosis DVT when other tests are negative i.e. Calf vein DVT • Diagnostic CO2 venography may be use in patients who can not have IV contrast • Adjunct to intervention • Confirms extent of occlusive disease • Monitors progress of treatment during venous lysis • IVUS may be more sensitive, but venography is still needed for stent placement • Defines extent and volume of VMs at time of embolization Venography Interpretation • X-Ray imaging is dependent on the attenuation difference between different types of tissue • Blood vessels can not be distinguished from soft tissue due to small attenuation differences • Intraluminal pathology often has similar attenuation to the blood vessels itself • A Contrast agent is needed to distinguish objects within the lumen of a vessel and to distinguish the vessel from adjacent soft tissue Venography Interpretation • The quality of imaging depends on the degree of tissue contrast at the time the picture is taken • Contrast “strength” • Contrast timing • Intraluminal pathology such as thrombus will appear as areas where contrast can not go (filling defects) • Morphologic abnormalities will appear as aberrant anatomy or enlarged lumens • Aneurysms • Venous Malformations Venography Technique for LE Thrombus • A superficial vein is cannulated on the medial aspect of the foot adjacent to the great toe • Contrast is injected and images are obtained beginning in the foot • Tourniquets are applied to force contrast into the deep venous system • More than 150 ml of 30% contrast is needed to adequately visualizes the LE veins • Contrast dilution results in poor iliac vein opacification • Occluded vein will not fill with contrast which does not confirm a DVT Venography LE DVT Venography Digital Subtraction Technique • Digital imaging with or without subtraction has replaced plain film imaging • Advantages • Rapid acquisition • Better discrimination of contrast filled structures • Disadvantages • Decreased resolution • Subtraction artifacts due to motion • Low dynamic range (“burn out” artifact or “glare”) • New flat panel detectors have a higher dynamic range reducing this effect Venography DSA Technique • Subtraction technique improves visualization of thrombus in vein • Catheter markers are easier to see in the non-subtracted image Venography DSA Technique Glare artifact prevents visualization of peripheral PA branches Reduced resolution of peripheral branches Venography Carbon Dioxide Contrast • CO2 gas can be used as a contrast medium for performing venography • Contrast allergy • Renal dysfunction • CO2 delivery systems are not standardized • Imaging resolution is limited • Complication have been reported Venography Iliac Vein Obstruction • The use of venography alone for the detection of iliac vein compression syndrome is problematic • Compared to IVUS single plane venography had poor sensitivity (45%) and negative predictive value (49%) in the detection of an obstruction of greater than 70% (P Neglén et. al. 2002) • VIDIO trial (2014-2015) • Compared IVUS to multiplanar venography • IVUS detected 88% more lesions • Venography missed lesion in 29% of patients Venography Iliac Vein Obstruction: Technique • • • • Contrast should be injected in the iliac vein Steep oblique views help to visualize narrowing Valsalva maneuver can accentuate lesion Venographic findings • Effacement • Filling of collaterals • Retrograde filling of internal iliac vein • Venography can provide some information on the physiologic impact of the lesion • Venography is needed for treatment Venography Iliac Vein Obstruction Venography Iliac Vein Obstruction 50 Y.O man Supine venogram 45 Y.O Woman with left leg swelling Supine venogram Valsalva Venography Iliac Vein Obstruction Cross pelvic collateral Venography Direct Venography • Traditional venography rarely fills focal lesions • Direct venography (varicography) of focal complex venous pathology is essential for treatment • Defines extent and lesion volume • Distinguishes between normal and abnormal venous structures • Determines effectiveness of treatment • Technique • Ultrasound is used to guide needle access into lesion • Contrast is injected under direct fluoroscopy to fill the lesion Direct Venography Venous Malformations Direct Venography Pelvic Veins Venography Conclusion • As a diagnostic tool, venography has been supplanted by cross sectional imaging modalities • Venography is an essential imaging tool to guide interventions • Iliac occlusive disease is better evaluated with IVUS but venography is still needed to treat • In the setting of complex venous anomalies direct venography (varicography) is able to define vascular anatomy better than cross sectional imaging • Direct venography is essential for treatment of complex venous lesions