Response/Recommendation 1: The use of lower extremity venograms for routine diagnosis of lower extremity deep venous thrombosis (DVT) is not recommended. For patients with suspicion of lower leg DVT requiring imaging, venous ultrasound (VUS) is recommended as the first diagnostic modality.
Strength of Recommendation: Strong.
Response/Recommendation 2: In patients with suspicion of iliac or vena cava thrombosis, as well as inconclusive or impossible to perform VUS, computer tomography venography (CTV) or magnetic resonance venography (MRV) should be performed, based on availability and center experience.
Strength of Recommendation: Moderate.
Response/Recommendation 3: In the patients with strong suspicion for lower extremity DVT and inconclusive or impossible to perform VUS, examination of the veins below the inguinal ligament should be done with CTV, MRV or contrast phlebography.
Strength of Recommendation: Moderate.
Response/Recommendation 4: In clinical trials with a study endpoint including the presence of lower leg asymptomatic DVT, the use of contrast venography may be performed as these are required by the regulatory bodies.
Strength of Recommendation: Moderate.
Rationale: In the current DVT diagnostic algorithm, the initial imaging method of patients with high clinical suspicion for lower leg DVT remains the VUS1–3. High accuracy of the sonographic examination-based strategy was confirmed in several studies and meta-analyses as well as emphasized in several guideline documents1–10.
Historically, traditional contrast venography, based on direct lower leg intravenous contrast injection, was used as the first objective imaging modality and for many years had been considered the “gold standard” for diagnosis of DVT11,12. Before the modern VUS era, due to limitations concerning other available diagnostic methods, including plethysmography, thermography, continuous-wave Doppler examination or isotopic studies, phlebography became another standard diagnostic imaging method to confirm DVT13–18. The rates of diagnosed DVT by bilateral venography in orthopaedic surgery studies became the reference values for further research on DVT prophylaxis efficacy in orthopaedic surgery. Chen et at., reported a 21.9% DVT incidence (with proximal DVT rate – 4%) after arthroscopic posterior cruciate ligament reconstruction19. In a study by Kim et al., 26% of the bilateral venograms turned out to be positive for DVT in patients after total hip arthroplasty (THA)20. Clarke et al., in a venography-based study dedicated to hip and knee arthroplasty patients not receiving thromboprophylaxis, found a 32% DVT rate after THA (proximal DVT – 16%) and 66% DVT rate after total knee replacement (TKA) (proximal DVT – 16%)21. A systematic review of the prospective clinical studies on DVT prevalence, with the use of contrast venography, in patients undergoing elective hip or knee surgery documented the presence of DVT in the operated leg in 16.7% of THA patients and in 33.8% of TKA patients. At the same time, DVT presence in the contralateral leg was noted in 4-5% of the cases22.
Contrast phlebography, together with venous thromboembolism (VTE) symptom evaluation, became another standard efficacy outcome evaluation method in a number of clinical trials including thromboprophylaxis trials in major orthopaedic surgery, as well as other specialties23–26. The common use of contrast venography in VTE prophylaxis trials reflects not only its accuracy in diagnosing DVT in the symptomatic patients, but also the possibility of diagnosing the presence of asymptomatic DVT27,28.
In contrast to diagnosis oriented on the symptomatic leg, implementation of bilateral phlebography allows one to evaluate the presence of asymptomatic thrombosis in both extremities. Besides high sensitivity, including in the diagnosis of asymptomatic DVT cases, the advantages of direct contrast venography include the possibility of visualizing calf vein DVT as well as non-occlusive thrombotic changes29–33.
Several studies, using contrast venography as the reference method, confirmed the efficacy of VUS in the diagnosis of DVT. However, the reported high sensitivity of the VUS shown in the femoro-popliteal segment decreases in below the knee veins34–38. It should be mentioned that the presence of symptomatic as well as asymptomatic DVT, including below the knee and non-occlusive DVT, frequently became the endpoint for clinical trials, especially in trials dedicated to VTE prophylaxis. Barnes et al., in a study based on combined B-mode/duplex Doppler scanning and venography, compared the results of routine postoperative screening for DVT in 158 THA patients. With a 12% incidence of proximal DVT (and total DVT rate of 30% including calf vein DVT), the duplex scan had a sensitivity of 79%, specificity of 98%, and accuracy of 97%, in relation to venography as the reference method39.
Despite the fact that phlebography was considered to be the “gold standard” for diagnosis of DVT, the possibility of inadequate results (evaluation) when using this technique remains significant, reaching as high as 6 to 20%40–43. Important points of concern include limited intra- and inter-observer agreement on venography results, as well as the lack of proper filling of the entire lower leg venous system (especially when injecting contrast into the foot vein for proximal deep vein segment visualization)43–49.
The technical progress of the ultrasound (US) technology as well as an improvement in diagnostic protocols based on compression US as well as duplex Doppler examination increased sensitivity and specificity of the sonographic examination in DVT diagnosis. Simultaneously, the invasiveness of phlebography related to the contrast injection as well as significant exposure to radiation, together with an improvement in the alternative methods nowadays limits the use of phlebography in daily practice. Besides the adverse effects related to phlebography performance, potential contraindications should also be mentioned, including contrast allergies as well as potential for renal impairment50–52.
Taking into account the clinical practice as well as method limitations, standard venography is now rarely used in daily clinical practice and its practical implementation in DVT patient management concerns mostly patients undergoing acute DVT catheter-directed thrombolysis or endovascular revascularization as well as chronic post-thrombotic venous obstruction treatment. In cases of proximal (including iliac) venous thrombosis suspicion and non-conclusive results of the US examination, CTV or MRV imaging is currently preferred to contrast phlebography53. The use of bilateral direct contrast venography remains an interesting option in clinical trials evaluating symptomatic and asymptomatic lower leg DVT.
CTV is efficacious in the diagnosis of proximal lower leg DVT54. CTV also more clearly demonstrates thrombus extension into the veins above the inguinal ligament or inferior vena cava than conventional contrast venography55,56. The costs of CTV examination, as well as its availability together with the invasiveness of the CTV study (contrast injection, radiation exposure) limit its use as a diagnostic measure to cases with diagnostic problems as well as inconclusive results of previous imaging studies, especially if proximal DVT is suspected. The use of CTV as the screening method for lower leg DVT in clinical studies on thromboprophylaxis is still rather rare57.
An important clinical subject related to CTV as a diagnostic method is the possibility of simultaneous lower leg CTV performance in patients undergoing computer tomography pulmonary artery angiography (CTPAA) because of pulmonary embolism (PE) suspicion. As suggested in several studies dedicated to this topic, CTV simultaneously performed with CTPAA offers limited value for detecting DVT and should not be performed as a routine screening test58.
Looking for less invasive and simplified diagnostic options of the venous system in patients with suspected PE undergoing CTPAA, the use of lower leg sonographic examination instead of the CTV was also proposed. In the Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) study, CTV performed after CTPAA showed that lower extremity imaging detects about 7% more patients requiring anticoagulation than CTPAA alone59. In 711 patients of the same study (PIOPED II) the accuracy of the CTV was compared with compression US. According to results, there was 95.5% concordance between CTV and sonography for DVT diagnosis or exclusion, and the sensitivity and specificity of combined computed tomographic angiography (CTA) and CTV were equivalent to those of combined CTA and sonography59.
Despite promising results, the role of MRV in lower leg DVT diagnosis is still under evaluation. According to a meta-analysis, similar sensitivity and specificity of MRV and VUS is suggested (especially in the femoropopliteal segment)60. Due to the heterogenicity of the studies, as well as differences in magnetic resonance imaging (MRI) diagnostic protocols, the promising results of the available studies have to be repeated and confirmed in a large number of patients and diagnostic centers. Another option is an identification of DVT by means of direct thrombus imaging61. MRI can also be used to assess the characteristic of the thrombosis to help differentiate between acute, subacute and chronic changes62. Due to the costs as well as method availability, there is, for now, no argument supporting the replacement of US with MRV as a first-line imagining modality in the patients with DVT suspicion. As an alternative diagnostic tool, MRV can be considered for patients in whom venous US is not possible to perform or the results are inconclusive63. Similar to CTV, one of the important advantages of the MRV study is the potential for pelvic vein or retroperitoneal vein visualization, which is not always correctly seen and assessed in the VUS examination.
1. Bates SM, Jaeschke R, Stevens SM, et al. Diagnosis of DVT: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e351S-e418S. doi:10.1378/chest.11-2299
2. Needleman L, Cronan JJ, Lilly MP, et al. Ultrasound for Lower Extremity Deep Venous Thrombosis: Multidisciplinary Recommendations From the Society of Radiologists in Ultrasound Consensus Conference. Circulation. 2018;137(14):1505-1515. doi:10.1161/CIRCULATIONAHA.117.030687
3. Kakkos SK, Gohel M, Baekgaard N, et al. Editor’s Choice – European Society for Vascular Surgery (ESVS) 2021 Clinical Practice Guidelines on the Management of Venous Thrombosis. Eur J Vasc Endovasc Surg Off J Eur Soc Vasc Surg. 2021;61(1):9-82. doi:10.1016/j.ejvs.2020.09.023
4. Cogo A, Lensing AW, Koopman MM, et al. Compression ultrasonography for diagnostic management of patients with clinically suspected deep vein thrombosis: prospective cohort study. BMJ. 1998;316(7124):17-20. doi:10.1136/bmj.316.7124.17
5. Schellong SM, Schwarz T, Halbritter K, et al. Complete compression ultrasonography of the leg veins as a single test for the diagnosis of deep vein thrombosis. Thromb Haemost. 2003;89(2):228-234.
6. Agnelli G, Volpato R, Radicchia S, et al. Detection of asymptomatic deep vein thrombosis by real-time B-mode ultrasonography in hip surgery patients. Thromb Haemost. 1992;68(3):257-260.
7. Kassaï B, Boissel J-P, Cucherat M, Sonie S, Shah NR, Leizorovicz A. A systematic review of the accuracy of ultrasound in the diagnosis of deep venous thrombosis in asymptomatic patients. Thromb Haemost. 2004;91(4):655-666. doi:10.1160/TH03-11-0722
8. Gibson NS, Schellong SM, Kheir DYE, et al. Safety and sensitivity of two ultrasound strategies in patients with clinically suspected deep venous thrombosis: a prospective management study. J Thromb Haemost JTH. 2009;7(12):2035-2041. doi:10.1111/j.1538-7836.2009.03635.x
9. Kraaijpoel N, Carrier M, Le Gal G, et al. Diagnostic accuracy of three ultrasonography strategies for deep vein thrombosis of the lower extremity: A systematic review and meta-analysis. PloS One. 2020;15(2):e0228788. doi:10.1371/journal.pone.0228788
10. Ageno W, Camporese G, Riva N, et al. Analysis of an algorithm incorporating limited and whole-leg assessment of the deep venous system in symptomatic outpatients with suspected deep-vein thrombosis (PALLADIO): a prospective, multicentre, cohort study. Lancet Haematol. 2015;2(11):e474-480. doi:10.1016/S2352-3026(15)00190-8
11. Bauer G. A venographic study of thromboembolic problems. Acta Chir Scand. 1940;84(Suppl 61):1-75.
12. Haeger K, Nylander G. Acute phlebography. Triangle Sandoz J Med Sci. 1967;8(1):18-26.
13. Moser KM, Brach BB, Dolan GF. Clinically suspected deep venous thrombosis of the lower extremities. A comparison of venography, impedance plethysmography, and radiolabeled fibrinogen. JAMA. 1977;237(20):2195-2198.
14. Watz R, Ek I, Bygdeman S. Noninvasive diagnosis of acute deep vein thrombosis. A comparison between thermography, plethysmography and phlebography. Acta Med Scand. 1979;206(6):463-466. doi:10.1111/j.0954-6820.1979.tb13547.x
15. Sandler DA, Martin JF, Duncan JS, et al. Diagnosis of deep-vein thrombosis: comparison of clinical evaluation, ultrasound, plethysmography, and venoscan with X-ray venogram. Lancet Lond Engl. 1984;2(8405):716-719. doi:10.1016/s0140-6736(84)92625-4
16. Høgevold HE, Høiseth A, Reikerås O. Deep vein thrombosis after total hip replacement. A venographic study. Acta Radiol Stockh Swed 1987. 1990;31(6):571-573.
17. Kristo DA, Perry ME, Kollef MH. Comparison of venography, duplex imaging, and bilateral impedance plethysmography for diagnosis of lower extremity deep vein thrombosis. South Med J. 1994;87(1):55-60. doi:10.1097/00007611-199401000-00012
18. Zhang H, Mao P, Wang C, et al. Incidence and risk factors of deep vein thrombosis (DVT) after total hip or knee arthroplasty: a retrospective study with routinely applied venography. Blood Coagul Fibrinolysis Int J Haemost Thromb. 2017;28(2):126-133. doi:10.1097/MBC.0000000000000556
19. Chen D, Li Q, Rong Z, et al. Incidence and risk factors of deep venous thrombosis following arthroscopic posterior cruciate ligament reconstruction. Medicine (Baltimore). 2017;96(22):e7074. doi:10.1097/MD.0000000000007074
20. Kim Y-H, Oh SH, Kim JS. Incidence and natural history of deep-vein thrombosis after total hip arthroplasty. A prospective and randomised clinical study. J Bone Joint Surg Br. 2003;85(5):661-665.
21. Clarke MT, Green JS, Harper WM, Gregg PJ. Screening for deep-venous thrombosis after hip and knee replacement without prophylaxis. J Bone Joint Surg Br. 1997;79(5):787-791. doi:10.1302/0301-620x.79b5.7627
22. Lee AYY, Gent M, Julian JA, et al. Bilateral vs. ipsilateral venography as the primary efficacy outcome measure in thromboprophylaxis clinical trials: a systematic review. J Thromb Haemost JTH. 2004;2(10):1752-1759. doi:10.1111/j.1538-7836.2004.00915.x
23. Dechavanne M, Ville D, Berruyer M, et al. Randomized trial of a low-molecular-weight heparin (Kabi 2165) versus adjusted-dose subcutaneous standard heparin in the prophylaxis of deep-vein thrombosis after elective hip surgery. Haemostasis. 1989;19(1):5-12. doi:10.1159/000215882
24. Moser G, Krähenbühl B, Donath A. [Prevention of deep venous thrombosis (TVP) and pulmonary embolism. Comparison of heparin (3 x 5000 IU/day), heparin (2 x 5000 IU/day) + 0.5 mg dihydroergot, and physiotherapy (intermittent compression stockings + physical exercise). Value of Doppler diagnosis in systematic detection of TVP compared with phlebography and scanning of the legs using labelled fibrinogen]. Helv Chir Acta. 1980;47(1-2):145-149.
25. Haentjens P. Thromboembolic prophylaxis in orthopaedic trauma patients: a comparison between a fixed dose and an individually adjusted dose of a low molecular weight heparin (nadroparin calcium). Injury. 1996;27(6):385-390. doi:10.1016/0020-1383(96)00042-3
26. Jørgensen PS, Warming T, Hansen K, et al. Low molecular weight heparin (Innohep) as thromboprophylaxis in outpatients with a plaster cast: a venografic controlled study. Thromb Res. 2002;105(6):477-480. doi:10.1016/s0049-3848(02)00059-2
27. Warwick D, Harrison J, Whitehouse S, Mitchelmore A, Thornton M. A randomised comparison of a foot pump and low-molecular-weight heparin in the prevention of deep-vein thrombosis after total knee replacement. J Bone Joint Surg Br. 2002;84(3):344-350. doi:10.1302/0301-620x.84b3.12372
28. Rong Z, Xu Z, Sun Y, et al. Deep venous thrombosis in the nonoperated leg after primary major lower extremity arthroplasty: a retrospective study based on diagnosis using venography. Blood Coagul Fibrinolysis Int J Haemost Thromb. 2015;26(7):762-766. doi:10.1097/MBC.0000000000000323
29. Cowell GW, Reid JH, Simpson AJ, Murchison JT. A profile of lower-limb deep-vein thrombosis: the hidden menace of below-knee DVT. Clin Radiol. 2007;62(9):858-863; discussion 864-865. doi:10.1016/j.crad.2007.01.027
30. Kälebo P, Anthmyr BA, Eriksson BI, Zachrisson BE. Phlebographic findings in venous thrombosis following total hip replacement. Acta Radiol Stockh Swed 1987. 1990;31(3):259-263.
31. Ascani A, Radicchia S, Parise P, Nenci GG, Agnelli G. Distribution and occlusiveness of thrombi in patients with surveillance detected deep vein thrombosis after hip surgery. Thromb Haemost. 1996;75(2):239-241.
32. Nillius AS, Nylander G. Deep vein thrombosis after total hip replacement: a clinical and phlebographic study. Br J Surg. 1979;66(5):324-326. doi:10.1002/bjs.1800660508
33. Björgell O, Nilsson PE, Jarenros H. Isolated nonfilling of contrast in deep leg vein segments seen on phlebography, and a comparison with color Doppler ultrasound, to assess the incidence of deep leg vein thrombosis. Angiology. 2000;51(6):451-461. doi:10.1177/000331970005100602
34. Mani R, Regan F, Sheridan J, Batty V. Duplex ultrasound scanning for diagnosing lower limb deep vein thrombosis. Dermatol Surg Off Publ Am Soc Dermatol Surg Al. 1995;21(4):324-326. doi:10.1111/j.1524-4725.1995.tb00182.x
35. Heijboer H, Büller HR, Lensing AW, Turpie AG, Colly LP, ten Cate JW. A comparison of real-time compression ultrasonography with impedance plethysmography for the diagnosis of deep-vein thrombosis in symptomatic outpatients. N Engl J Med. 1993;329(19):1365-1369. doi:10.1056/NEJM199311043291901
36. Mitchell DC, Grasty MS, Stebbings WS, et al. Comparison of duplex ultrasonography and venography in the diagnosis of deep venous thrombosis. Br J Surg. 1991;78(5):611-613. doi:10.1002/bjs.1800780528
37. Markel A, Weich Y, Gaitini D. Doppler ultrasound in the diagnosis of venous thrombosis. Angiology. 1995;46(1):65-73. doi:10.1177/000331979504600109
38. Fürst G, Kuhn FP, Trappe RP, Mödder U. [The diagnosis of deep venous thromboses of the leg. Color-Doppler sonography versus phlebography]. ROFO Fortschr Geb Rontgenstr Nuklearmed. 1990;152(2):151-158. doi:10.1055/s-2008-1046842
39. Barnes CL, Nelson CL, Nix ML, McCowan TC, Lavender RC, Barnes RW. Duplex scanning versus venography as a screening examination in total hip arthroplasty patients. Clin Orthop. 1991;(271):180-189.
40. Kälebo P, Ekman S, Lindbratt S, et al. Percentage of inadequate phlebograms and observer agreement in thromboprophylactic multicenter trials using standardized methodology and central assessment. Thromb Haemost. 1996;76(6):893-896.
41. Naidich JB, Feinberg AW, Karp-Harman H, Karmel MI, Tyma CG, Stein HL. Contrast venography: reassessment of its role. Radiology. 1988;168(1):97-100. doi:10.1148/radiology.168.1.3289098
42. Lensing AW, Büller HR, Prandoni P, et al. Contrast venography, the gold standard for the diagnosis of deep-vein thrombosis: improvement in observer agreement. Thromb Haemost. 1992;67(1):8-12.
43. McLachlan MS, Thomson JG, Taylor DW, Kelly ME, Sackett DL. Observer variation in the interpretation of lower limb venograms. AJR Am J Roentgenol. 1979;132(2):227-229. doi:10.2214/ajr.132.2.227
44. Hull RD, Hirsh J, Carter CJ, et al. Diagnostic efficacy of impedance plethysmography for clinically suspected deep-vein thrombosis. A randomized trial. Ann Intern Med. 1985;102(1):21-28. doi:10.7326/0003-4819-102-1-21
45. Björgell O, Nilsson PE, Benoni G, Bergqvist D. Symptomatic and asymptomatic deep vein thrombosis after total hip replacement. Differences in phlebographic pattern, described by a scoring of the thrombotic burden. Thromb Res. 2000;99(5):429-438. doi:10.1016/s0049-3848(00)00274-7
46. Kalodiki E, Nicolaides AN, Al-Kutoubi A, Cunningham DA, Mandalia S. How “gold” is the standard? Interobservers’ variation on venograms. Int Angiol J Int Union Angiol. 1998;17(2):83-88.
47. Couson F, Bounameaux C, Didier D, et al. Influence of variability of interpretation of contrast venography for screening of postoperative deep venous thrombosis on the results of a thromboprophylactic study. Thromb Haemost. 1993;70(4):573-575.
48. Kilpatrick TK, Lichtenstein M, Andrews J, Gibson RN, Neerhut P, Hopper J. A comparative study of radionuclide venography and contrast venography in the diagnosis of deep venous thrombosis. Aust N Z J Med. 1993;23(6):641-645. doi:10.1111/j.1445-5994.1993.tb04719.x
49. Wille-Jørgensen P, Borris L, Jørgensen LN, et al. Phlebography as the gold standard in thromboprophylactic studies? A multicenter interobserver variation study. Acta Radiol Stockh Swed 1987. 1992;33(1):24-28.
50. Lensing AW, Prandoni P, Büller HR, Casara D, Cogo A, ten Cate JW. Lower extremity venography with iohexol: results and complications. Radiology. 1990;177(2):503-505. doi:10.1148/radiology.177.2.2217792
51. AbuRahma AF, Powell M, Robinson PA. Prospective study of safety of lower extremity phlebography with nonionic contrast medium. Am J Surg. 1996;171(2):255-260. doi:10.1016/S0002-9610(97)89562-1
52. Berge T, Bergqvist D, Efsing HO, Hallböök T, Lindblad B, Lindhagen A. Complications of phlebography: a randomised comparison between an ionic and a non-ionic contrast medium. Clin Radiol. 1981;32(5):595-598. doi:10.1016/s0009-9260(81)80197-3
53. Karande GY, Hedgire SS, Sanchez Y, et al. Advanced imaging in acute and chronic deep vein thrombosis. Cardiovasc Diagn Ther. 2016;6(6):493-507. doi:10.21037/cdt.2016.12.06
54. Baldt MM, Zontsich T, Stümpflen A, et al. Deep venous thrombosis of the lower extremity: efficacy of spiral CT venography compared with conventional venography in diagnosis. Radiology. 1996;200(2):423-428. doi:10.1148/radiology.200.2.8685336
55. Lim K-E, Hsu W-C, Hsu Y-Y, Chu P-H, Ng C-J. Deep venous thrombosis: comparison of indirect multidetector CT venography and sonography of lower extremities in 26 patients. Clin Imaging. 2004;28(6):439-444. doi:10.1016/S0899-7071(03)00319-X
56. Kim T, Murakami T, Hori M, Kumano S, Sakon M, Nakamura H. Efficacy of multi-slice helical CT venography for the diagnosis of deep venous thrombosis: comparison with venous sonography. Radiat Med. 2004;22(2):77-81.
57. Chang MJ, Song MK, Kyung MG, Shin JH, Chang CB, Kang S-B. Incidence of deep vein thrombosis before and after total knee arthroplasty without pharmacologic prophylaxis: a 128-row multidetector CT indirect venography study. BMC Musculoskelet Disord. 2018;19(1):274. doi:10.1186/s12891-018-2166-8
58. Reichert M, Henzler T, Krissak R, et al. Venous thromboembolism: additional diagnostic value and radiation dose of pelvic CT venography in patients with suspected pulmonary embolism. Eur J Radiol. 2011;80(1):50-53. doi:10.1016/j.ejrad.2010.12.101
59. Goodman LR, Stein PD, Matta F, et al. CT venography and compression sonography are diagnostically equivalent: data from PIOPED II. AJR Am J Roentgenol. 2007;189(5):1071-1076. doi:10.2214/AJR.07.2388
60. Sampson FC, Goodacre SW, Thomas SM, van Beek EJR. The accuracy of MRI in diagnosis of suspected deep vein thrombosis: systematic review and meta-analysis. Eur Radiol. 2007;17(1):175-181. doi:10.1007/s00330-006-0178-5
61. Mendichovszky IA, Priest AN, Bowden DJ, et al. Combined MR direct thrombus imaging and non-contrast magnetic resonance venography reveal the evolution of deep vein thrombosis: a feasibility study. Eur Radiol. 2017;27(6):2326-2332. doi:10.1007/s00330-016-4555-4
62. Arnoldussen C, Strijkers R, Lambregts D, Lahaye M, de Graaf R, Wittens C. Feasibility of identifying deep vein thrombosis characteristics with contrast enhanced MR-Venography. Phlebology. 2014;29(1 suppl):119-124. doi:10.1177/0268355514529697
63. Gehl HB, Bohndorf K, Günther RW. [MR-angiography (MRA) in deep leg and pelvic venous thrombosis: a comparison with phlebography]. ROFO Fortschr Geb Rontgenstr Nuklearmed. 1990;153(6):654-657. doi:10.1055/s-2008-1033459