May-Thurner syndrome is caused by blockade of local venous flow due to local vascular intimal proliferation, caused by repeated pulsatile compression of the iliac or iliofemoral vein between the iliac artery and the lumbar spine. In this case, we confirmed May-Thurner syndrome using lower extremity computed tomographic angiography and venography. However, on venography, it was impossible to distinguish the left iliac vein from the collateral vein; a thrombus was also seen, although some of the thrombus was not seen clearly. These problems were overcome with use of intravascular ultrasound. We report on intravascular ultrasound guided treatment of May-Thurner syndrome.

Introduction
 Case report
 Discussion
 References

• Hoon Kang(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Jung Il Hyung(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Chung Kang(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Dong In Nam(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Sang Sun Lee(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Hong Ju An(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Ho Yeong Song(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Sang Cheol Cho(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Won Yu Kang(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital) Corresponding author
• Sun Ho Hwang(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)
• Wan Kim(Division of Cardiology, Department of Internal Medicine, Gwangju Veterans Hospital)