Causes of Leg Swelling. How good is CT for DVT? Direct CT Venography. Lower Extremity Venous Thrombosis and Leg Swelling: The Role of CT Venography

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1 Lower Extremity Venous Thrombosis and Leg Swelling: The Role of CT Venography Bart Dolmatch, MD Professor of Radiology UTSW Medical Center Dallas, TX Causes of Leg Swelling Venous thrombosis Venous stenosis Other causes Venous reflux Hypoproteinemia CHF Lymphedema Arteriovenous Fistulae Femoropopliteal Venous Thrombosis How good is CT for DVT? % sensitive % specific 1 92% Positive Predictive 2 100% Negative Predictive 2 Comparable to duplex ultrasound 1 Various refs. See Kanne JP and Lalani TA. Circulation. 2004;109[suppl 1]:I-15-I-21 2 Begemann PGC et a;. JCAT (3): CT venography for DVT Sensitive and accurate Often part of another exam Not viable except in rare situations Radiation exposure Cost Direct CT Venography Pedal IV 50-60mgI/ml (1/4 th -1/5 th dilution 300mgI/ml 3ml/sec with ankle tourniquet 3ml/sec with ankle tourniquet Delay seconds Scan foot to pelvis Collimation mm with 20-25% overlap CT Symposium 1

2 Tourniquet IV Deep Vei ns Superficial Veins Direct CT Venography Deep Femoral Vein Tributaries/Collaterals Chronically occluded Right Superficial Femoral Vein --Saphenous Vein Superficial calf vein tributaries/collaterals Applications for CT Venography Understanding Venous Disease all starts with Virchow Iliac Venous Stenosis and Thrombosis 1. May-Thurner Syndrome 2. Cockett s Syndrome Virchow observed that iliofemoral DVT 5x more likely in left leg than right McMurrich 1957: May and Thurner May R, Thurner J "The cause of the predominantly sinistral occurrence of thrombosis of the pelvic veins". Angiology (1957); 8 (5): McMurrich first described left iliac vein compression CT Symposium 2

3 May and Thurner 430 autopsies 22% of had fibrous bands ( spurs ) in the lumen of the left illiac vein. The spurs occurred at the site where the right iliac artery crosses over the left iliac vein. Hypothesized to be due to chronic compression of L iliac vein between R common iliac artery and 5 th lumbar vertebrae. May-Thurner Syndrome Women (70%), young to middle age Acute: Often due to iliofemoral DVT Chronic: Venous insufficiency and venous hypertension Lower extremity pain, venous claudication Swelling Varicose veins Venous stasis skin changes Iliofemoral DVT: Cockett s Syndrome 1967 Cockett reported first clinical series of 57 pts with acute iliofemoral DVT secondary to iliac vein compression. M-T Synd + Acute DVT = Cockett s Synd. Diagnosis of M-T and Cockett s S Ultrasound T h i ll diffi lt t i li ili i (d Technically difficult to visualize iliac veins (deep in the pelvis behind fat, bladder and bowel) 2-5% of all lower extremity DVT CT Symposium 3

4 CT Diagnosis of M-T and Cockett s S 45 of 56 patients had a detectable abnormality that was at least partly responsible for acute DVT 1 27 of 44 patients with acute iliofemoral DVT had findings of May-Thurner detectable on CT 1 1 Chung JW et al. J Vasc Interv Rad. 2004;15: C CIA (white arrow) L CIV (black arrow) VRT shows vascular anatomy. Extrinsic impression of R CIA on L CIV Don t a lot of normal people have findings of May-Thurner? Yes, often incidental and asymptomatic But in acute iliofemoral vein thrombosis It is extremely common It is permissive at least partly attributable Treatment with thrombolytics and stents relieves or improves symptoms in 75% 1 of symptomatic patients suggesting an important role in pts w/ Sx s transpelvic collateral veins 1 Raju S et al. J Vasc Surg 2006;44: Treatment of May-Thurner Open surgical bypass Repair requires major surgery with laparotomy or retroperitoneal iliac exposure Endovascular treatments Angioplasty Stenting Angioplasty or Stenting? 15 of 16 pts (follow-up 10 mos) for stenting. 3 of 3 patients with only angioplasty rethrombosed. (Kim JY, 2006) 100% stent patency after 3 years in 8 patients (Binkert et al.) 13 of 15 (87%) stent patency (follow-up 16 mo) Lamont et al. Venous stenting: The current standard of care CT Symposium 4

5 Indirect CT: Just OK! Direct CT Venography: Superior Other uses for Direct CTV: Consider when duplex isn t diagnostic and a venogram is requested Clot from SVT entering Popliteal Vein 29 yo woman Left calf pain and swelling Protein S deficiency CT Symposium 5

6 Etiology of left calf swelling? May-Thurner permissive lesion Superficial Venous Thrombosis Protein S deficiency 69yo man with Bilateral Leg Swelling and Pain Left Leg Treatment was Warfarin Right Leg Primary Adenocarcinoma of the Lung Trousseau s Syndrome Superficial thrombophlebitis Visceral Malignancy (Lung) Conclusion Indirect CT Venography Excellent for DVT diagnosis Not practical due to radiation exposure, cost Iliac venous stenosis (w/wo thrombosis) May-Thurner Syndrome Crockett s Syndrome Direct CTV is useful for eval. and follow-up When conventional Venography is needed consider direct CT Venography CT Symposium 6